Publications by authors named "Houyu Zhang"

33 Publications

Prognostic Prediction of Cytogenetically Normal Acute Myeloid Leukemia Based on a Gene Expression Model.

Front Oncol 2021 27;11:659201. Epub 2021 May 27.

State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China.

Acute myeloid leukemia (AML) refers to a heterogeneous group of hematopoietic malignancies. The well-known European Leukemia Network (ELN) stratifies AML patients into three risk groups, based primarily on the detection of cytogenetic abnormalities. However, the prognosis of cytogenetically normal AML (CN-AML), which is the largest AML subset, can be hard to define. Moreover, the clinical outcomes associated with this subgroup are diverse. In this study, using transcriptome profiles collected from CN-AML patients in the BeatAML cohort, we constructed a robust prognostic Cox model named NEST (Nine-gEne SignaTure). The validity of NEST was confirmed in four external independent cohorts. Moreover, the risk score predicted by the NEST model remained an independent prognostic factor in multivariate analyses. Further analysis revealed that the NEST model was suitable for bone marrow mononuclear cell (BMMC) samples but not peripheral blood mononuclear cell (PBMC) samples, which indirectly indicated subtle differences between BMMCs and PBMCs. Our data demonstrated the robustness and accuracy of the NEST model and implied the importance of the immune dysfunction in the leukemogenesis that occurs in CN-AML, which shed new light on the further exploration of molecular mechanisms and treatment guidance for CN-AML.
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http://dx.doi.org/10.3389/fonc.2021.659201DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8190396PMC
May 2021

Self-Assembly of Metallo-Supramolecules with Dissymmetrical Ligands and Characterization by Scanning Tunneling Microscopy.

J Am Chem Soc 2021 01 4;143(2):1224-1234. Epub 2021 Jan 4.

College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, Guangdong 518055, China.

Asymmetrical and dissymmetrical structures are widespread and play a critical role in nature and life systems. In the field of metallo-supramolecular assemblies, it is still in its infancy for constructing artificial architectures using dissymmetrical building blocks. Herein, we report the self-assembly of supramolecular systems based on two dissymmetrical double-layered ligands. With the aid of ultra-high-vacuum, low-temperature scanning tunneling microscopy (UHV-LT-STM), we were able to investigate four isomeric structures corresponding to four types of binding modes of ligand with two major conformations complexes . The distribution of isomers measured by STM and total binding energy of each isomer obtained by density functional theory (DFT) calculations suggested that the most abundant isomer could be the most stable one with highest total binding energy. Finally, through shortening the linker between inner and outer layers and the length of arms, the arrangement of dissymmetrical ligand could be controlled within one binding mode corresponding to the single conformation for complexes .
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http://dx.doi.org/10.1021/jacs.0c12508DOI Listing
January 2021

Crystal Engineering of a Hydrazone Molecule toward High Elasticity and Bright Luminescence.

J Phys Chem Lett 2020 Nov 15;11(21):9178-9183. Epub 2020 Oct 15.

State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, China.

Flexible luminescent crystals have attracted increasing attention on account of the potential application value in optical material fields. How to design crystals with high elasticity and bright luminescence is an urgent duty that material researchers want to effectuate. Crystal engineering could achieve different crystal materials with various functions based on one molecular structure. Therefore, crystal engineering provides a potential strategy to improve the properties of flexible crystals. In this paper, we gave a pioneer work to improve the properties of flexible luminescent crystals by designing on crystal structure. By disclosing the relationship of structure-property, our work extracted the advantages (elasticity or bright emission) of two inferior crystals and obtained three elastic bending crystals with outstanding emission behaviors. Notably, our work not only achieves the fabrication of flexible crystals based on crystal engineering aspect but also provides good candidates for flexible optical waveguiding materials.
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http://dx.doi.org/10.1021/acs.jpclett.0c02623DOI Listing
November 2020

Targeting of apoptosis gene loci by reprogramming factors leads to selective eradication of leukemia cells.

Nat Commun 2019 12 6;10(1):5594. Epub 2019 Dec 6.

State Key Laboratory of Experimental Hematology, Beijing, China.

Applying somatic cell reprogramming strategies in cancer cell biology is a powerful approach to analyze mechanisms of malignancy and develop new therapeutics. Here, we test whether leukemia cells can be reprogrammed in vivo using the canonical reprogramming transcription factors-Oct4, Sox2, Klf4, and c-Myc (termed as OSKM). Unexpectedly, we discover that OSKM can eradicate leukemia cells and dramatically improve survival of leukemia-bearing mice. By contrast, OSKM minimally impact normal hematopoietic cells. Using ATAC-seq, we find OSKM induce chromatin accessibility near genes encoding apoptotic regulators in leukemia cells. Moreover, this selective effect also involves downregulation of H3K9me3 as an early event. Dissection of the functional effects of OSKM shows that Klf4 and Sox2 play dominant roles compared to c-Myc and Oct4 in elimination of leukemia cells. These results reveal an intriguing paradigm by which OSKM-initiated reprogramming induction can be leveraged and diverged to develop novel anti-cancer strategies.
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http://dx.doi.org/10.1038/s41467-019-13411-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6898631PMC
December 2019

Helical supramolecular polymer nanotubes with wide lumen for glucose transport: towards the development of functional membrane-spanning channels.

Chem Sci 2019 Oct 30;10(37):8648-8653. Epub 2019 Jul 30.

State Key Laboratory of Supramolecular Structure and Materials , College of Chemistry , Jilin University , Qianjin Street , Changchun , China . Email:

The manipulation of strong noncovalent interactions provides a concise and versatile strategy for constructing highly ordered supramolecular structures. By using a shape-persistent building block consisting of phenanthroline derivatives and two quadruply hydrogen-bonding AADD moieties, a type of precise helical supramolecular polymer (HSP) nanotube has been developed. The helical conformation of the supramolecular polymers has been proved various techniques, showing significantly expanded topologies of supramolecular polymers. From the production of new topological structures of supramolecular polymers, predictable properties and functions have arisen. In this study, the helical folding of supramolecular polymers gave rise to the generation of specific wide lumen structures that can be directly visualized TEM, and the resulting HSP nanotubes can puncture the lipid bilayer membrane to facilitate the transportation of glucose.
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http://dx.doi.org/10.1039/c9sc02336dDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6844296PMC
October 2019

Solvation-Enhanced Intermolecular Charge Transfer Interaction in Organic Cocrystals: Enlarged C-C Surface Close Contact in Mixed Packing between PTZ and TCNB.

ACS Omega 2019 Jun 17;4(6):10424-10430. Epub 2019 Jun 17.

State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry and College of Physics, Jilin University, Changchun 130012, P. R. China.

The mixed π-π packing of the donor (D) and acceptor (A) molecules is the highlighting feature of the intermolecular interactions following charge transfer (CT) issues in organic cocrystal systems. There is an inverse relationship between the D-A interplanar distance and the intermolecular CT interaction. However, the D-A C-C surface close contact (relative areas) on the intermolecular CT interactions in organic cocrystal systems is rarely investigated. Herein, we designed and constructed a novel cocrystal and its solvate cocrystal. The structural and electrostatic potential analyses suggest that the solvation destroys the N-H···N hydrogen bond interaction between phenothiazine (PTZ) and 1,2,4,5-tetracyanobenzene (TCNB), which causes the TCNB molecules to have a 90° rotation along the normal axis of the PTZ plane. Thus, the D-A C-C surface close contact is enlarged, strengthening the intermolecular π-π stacking interactions and intermolecular CT interaction between PTZ and TCNB, which are further evidenced by the absorption and Raman spectroscopic analyses. This study provides rare evidence of the enlarged C-C surface close contact in the mixed packing between D and A that greatly contributes to the intermolecular CT interaction in a D-A cocrystal system. It also provides a deeper understanding of the role of solvation in the structure-property relationship of organic cocrystal materials.
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http://dx.doi.org/10.1021/acsomega.9b01083DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6648522PMC
June 2019

Rigidified and expanded N-annulated perylenes as efficient donors in organic sensitizers for application in solar cells.

Phys Chem Chem Phys 2019 May 9;21(20):10488-10496. Epub 2019 May 9.

State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China.

A class of N-annulated perylene (NP)-based organic dyes used in dye-sensitized solar cells has been investigated by means of quantum chemical calculations. The NPs are rigidified with thiophene or benzene rings in both a one-sided and two-sided manner on a 5- or 6-member ring and are considered as electron donors in dyes. To gain a better understanding of the effect of such modulation of NP moieties on the dye performance, the geometrical and electronic structures, the optical absorption and intramolecular charge transfer properties of the dyes and dye-TiO complexes are analyzed in detail to establish the structure-property relationship. The calculated results indicate that the rigidified NP moieties could improve light-harvesting capacities, modulate the energy levels of frontier orbitals, accelerate intramolecular charge transfer by decreasing the aromaticity of the π-system, decreasing the reorganization energy and avoiding electon trapping in the possible multiple electron transfer pathways, and facilitate charge separation with a lower coulombic attractive energy. In particular, the bilateral dyes via a 6-member immobilization would be promising candidates with excellent performance. We hope that our calculations could give a more in-depth physical insight on the structure-property relationship and provide guidance for the exploration of high-performance NP-based dyes.
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http://dx.doi.org/10.1039/c9cp00779bDOI Listing
May 2019

Fluorescence Regulation and Photoresponsivity in AIEE Supramolecular Gels Based on a Cyanostilbene Modified Benzene-1,3,5-Tricarboxamide Derivative.

Chemistry 2019 Jan 4;25(1):315-322. Epub 2018 Dec 4.

State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China.

Supramolecular interactions play an important role in regulating the optical properties of molecular materials. Different arrangements of identical molecules can afford a more straightforward insight into the contributions of supramolecular interactions. Herein, a novel gelator, BTTPA, composed of a benzene-1,3,5-tricarboxamide (BTA) central unit functionalized with three cyanostilbenes is designed, which forms two kinds of gels in DMSO/water mixtures. Depending on the water volume content, the gels exhibit quite different aggregation-induced emission enhancement (AIEE) properties, with one emitting a green emission (G-gel), and the second emitting a blue emission (B-gel). The main reason for this difference is that water affects H-bonding and π-π interactions, further resulting in disparate packing modes of gelators. In addition, only the G-gel displays gel-to-sol transition accompanied with fluorescence switching according to the trans-cis photoisomerization of cyanostilbene under UV light irradiation. The B-gel does not exhibit any change because of its tight hexagonal packing arrangement. Such packing modes restricted the space in which molecules were located and inhibited the transformation of configuration of cyanostilbene. These phenomena underline the incomparable status of packing modes and molecular configuration in regulating fluorescence properties and photoresponse behavior in organic solid-state luminescent materials.
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http://dx.doi.org/10.1002/chem.201804135DOI Listing
January 2019

Quantum-Chemical Insights into the Phosphorescence Efficiencies of Blue-Emitting Platinum Complexes with Phenylene-Bridged Pincer Ligands.

Inorg Chem 2018 Oct 21;57(19):12174-12186. Epub 2018 Sep 21.

State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry , Jilin University , Changchun 130012 , P. R. China.

Blue phosphorescent platinum complexes with phenylene-bridged pincer ligands, [Pt(dmib)Cl] [1; dmib = m-bis(methylimidazolyl)benzene], [Pt(mizb)Cl] [2; mizb = bis( N-methylimidazolium)benzene], and [Pt(dpzb)Cl] [3; dpzb = m-bis(3,5-dimethylpyrazolyl)benzene], have been investigated theoretically to rationalize the marked differences of their phosphorescence efficiencies. On the basis of density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations, the geometrical and electronic structures, absorption and emission properties, and radiative and nonradiative processes are analyzed in detail. The emission from the emissive lowest triplet state (T) originates from a mixture of metal-to-ligand charge-transfer (MLCT) and intraligand charge-transfer (ILCT) states. The calculated radiative decay rate constants of T of the complexes are comparable and in the same order of magnitude with the experimental measurements. Therefore, the potential energy profiles for the deactivation processes from T via temperature-independent and -dependent pathways are explored to reveal the effect of nonradiative decay on phosphorescence. The calculated results indicate that the very weak emission of 3 could be ascribed to the deactivation process via the metal-centered (MC) state, which can be readily accessible via a spontaneous process from the T state. This work provides more in-depth insight into the nature of the emissive excited state, shielding light on a better understanding of the excited-state behavior of phosphorescent platinum complexes.
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http://dx.doi.org/10.1021/acs.inorgchem.8b01828DOI Listing
October 2018

Investigation of supramolecular interaction in 4, 4'-bipyridine crystal by hydrostatic pressure spectroscopies.

Spectrochim Acta A Mol Biomol Spectrosc 2018 Sep 4;202:70-75. Epub 2018 May 4.

State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, Jilin University, Changchun, PR China 130012.

The luminescence and structural changes of 4, 4'-bipyridine in the crystal and powder forms under the effect of high pressure applied by a diamond anvil cell has been investigated through the fluorescence and Raman spectroscopies. In its single crystal structure, the 4, 4'-bipyridine molecules are paralleled arranged with the identifiable CH⋯N and π⋯π interactions among molecules. However, in the powder form, these intermolecular interactions nearly diminish. The 4, 4'-bipyridine crystal shows the obvious bathochromic-shifting of the emission band, which is different from the powder sample that displays a fixed luminescent band during compression. Additionally, the Raman bands of them both show shifts to higher wavenumbers as different degrees. The detailed peak assignments are performed based on the theoretical calculation through B3LYP method. Comparisons in spectral behaviors between the crystal and powder under compression show the crystal form exhibits a superior mechanochromic performance relative to the powder one, because the intermolecular interactions in the crystal form play dominating roles and they can be easily tuned along with pressure in such a highly ordered structure compared to the powder form. The relation investigation between property and supramolecular interactions not only makes deeper understanding in the mechanochromic mechanisms of 4, 4'-bipyridine, but also gives a helpful reference for the molecular designs of coordination polymers and co-crystals with 4, 4'-bipyridine involved.
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http://dx.doi.org/10.1016/j.saa.2018.05.014DOI Listing
September 2018

Counteranion-Mediated Intrinsic Healing of Poly(ionic liquid) Copolymers.

ACS Appl Mater Interfaces 2018 Jan 4;10(2):2105-2113. Epub 2018 Jan 4.

State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Changchun 130012, P. R. China.

Fabrication of self-healing/healable materials using reversible interactions that are governed by their inherent chemical features is highly desirable because it avoids the introduction of extra groups that may present negative effects on their functions. The present study exploits the inherently featured electrostatic interactions of the ion pairs in polymeric ionic liquids (PILs) as the driving force to fabricate healable PIL copolymers. The healable PIL copolymers are fabricated through the copolymerization of the IL monomers with ethyl acrylate followed by the replacement of Br counteranions with bulkier ones such as bis(trifluoromethanesulfonyl)imide (TFSI). Without modifying the chemical structures of the PIL moieties, the healing performance of the as-prepared PIL copolymers can be effectively mediated by their counteranions. The PIL copolymers that do not possess healability when paired with Br counteranions become healable after exchanging the Br counteranions with larger-sized ones (e.g., TFSI). The PIL copolymers paired with bulky counteranions exhibit enhanced chain mobility and highly reversible ion-pair interactions, which facilitate the healing process. The PIL copolymers paired with TFSI anions can completely heal the damage/cut upon heating at 55 °C for 7.5 h. Meanwhile, the counteranions with larger sizes not only benefit the healing performance of the PIL copolymers but also enhance their ion conductivity. The ion conductivity of the PIL copolymers paired with TFSI is an order of magnitude higher than that of the PIL copolymers paired with Br. Therefore, the as-prepared healable PIL copolymers are potentially useful as solid electrolytes in PIL-based energy devices to improve their safety and reliability.
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http://dx.doi.org/10.1021/acsami.7b16880DOI Listing
January 2018

ESIPT-active organic compounds with white luminescence based on crystallization-induced keto emission (CIKE).

Chem Commun (Camb) 2017 Jul;53(55):7832-7835

State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China.

Structurally simple pyrazole derivatives that exhibit excited-state intramolecular proton transfer (ESIPT) were synthesized. While these compounds displayed deep violet fluorescence in solution, in the crystalline state they showed white emission from the enol and keto forms.
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http://dx.doi.org/10.1039/c7cc03758aDOI Listing
July 2017

1,3-Diaryl-β-diketone Organic Crystals with Red Amplified Spontaneous Emission.

Chempluschem 2016 Dec 28;81(12):1320-1325. Epub 2016 Sep 28.

State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China.

In this study, 1-[4-(dimethylamino)phenyl]-3-(1-hydroxynaphthalen-2-yl)propane-1,3-dione (DPHND) was designed and synthesized to construct red-emissive organic solids. Although DPHND was weakly yellow fluorescent in organic solvents, its emission intensity showed a significant enhancement when a relatively large amount of poor solvent was added, and displayed typical aggregation-induced enhanced emission (AIEE). Notably, the crystals formed by a solution-diffusion approach showed bright red fluorescence (λ =621 nm), which was greatly redshifted by about 60 nm compared with that in solution. Molecules in crystals took a planar conformation and formed a herringbone packing structure, which effectively avoided π⋅⋅⋅π interactions, and hence contributed to the enhancement of the fluorescent quantum yield. The fluorescence spectrum of the long striplike crystals of DPHND gradually narrowed accompanied by a dramatic enhancement of the intensity when the pump energy of the laser beam was increased (355 nm), which indicated that these red-emissive crystals displayed typical amplified spontaneous emission (ASE). In addition, DPHND with an extended π-conjugated structure clearly improved its thermostability compared with the previously reported analogues, which may pave the way for its application in future electrically driven organic solid-state lasers.
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http://dx.doi.org/10.1002/cplu.201600451DOI Listing
December 2016

Highly efficient blue solid emitters and tautomerization-induced ON/OFF fluorescence switching based on structurally simple 3(5)-phenol-1H-pyrazoles.

Chem Commun (Camb) 2016 Nov;52(89):13128-13131

State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, 2699 Qianjin Avenue, Changchun, P. R. China.

3(5)-Phenyl-1H-pyrazoles are employed in this study to develop highly efficient organic crystalline solids with deep-blue ESIPT fluorescence as well as provide novel experimental insight into the mechanism of ESIPT fluorescence and generate an intriguing fluorescence "ON/OFF" switching.
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http://dx.doi.org/10.1039/c6cc07300jDOI Listing
November 2016

On the properties of Se⋯N interaction: the analysis of substituent effects by energy decomposition and orbital interaction.

J Mol Model 2016 Jan 11;22(1):29. Epub 2016 Jan 11.

State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, Jilin University, Changchun, 130012, People's Republic of China.

The nature and strength of intermolecular Se⋯N interaction between selenium-containing compounds HSeX (X = CH3, NH2, CF3, OCH3, CN, OH, NO2, Cl, F), and NH3 have been investigated at the MP2/aug-cc-pVDZ level. The Se⋯N interaction is found to be dependent on the substituent groups, which greatly affect the positive electrostatic potential of Se atoms and the accepting electron ability of X-Se σ(∗) antibonding orbital. Energy decomposition of the Se ⋯N interaction reveals that electrostatic and induction forces are comparable in the weak-bonded complexes and induction becomes more significant in the complexes with strong electron-withdrawing substituents. Natural bond orbital (NBO) analysis indicates that the primary source of the induction is the electron transfer from the N lone pair to the X-Se σ(∗) antibonding orbital. The geometry of the complex and the interaction directionality of NH3 to X-Se bond can be regarded as a consequence of the exchange-repulsion. The topological analysis on the electron density reveals the nature of closed-shell interaction in these X-Se⋯N contacts. The Se⋯N interaction in the complexes with the strong electron-withdrawing substituent has a partly covalent character.
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http://dx.doi.org/10.1007/s00894-015-2901-0DOI Listing
January 2016

Reversible Piezofluorochromic Property and Intrinsic Structure Changes of Tetra(4-methoxyphenyl)ethylene under High Pressure.

J Phys Chem A 2015 Sep 20;119(35):9218-24. Epub 2015 Aug 20.

State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry and ‡State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Changchun 130012, People's Republic of China.

During the past decade, luminescent mechanochromism has received much attention. Despite the garnered attention, only a few studies have reported the effect of internal molecular structure change on the performance of mechanochromic fluorescence. Here, we chose tetra(4-methoxyphenyl)ethylene (TMOE) as a model molecule to study the correlation between structure and fluorescence property under a hydrostatic pressure produced by a diamond anvil cell (DAC). TMOE is a methoxy-substituted tetraphenylethylene (TPE) derivative and has a nearly centrosymmetric structure and a natural propeller shape. Ultraviolet-visible absorption and fluorescence spectra of TMOE and TPE in solution proved that the presence of methoxy groups in TMOE is responsible for the difference in fluorescence emissions of TMOE and TPE. Under a hydrostatic pressure, the in situ fluorescence spectra of TMOE at different concentrations show that the fluorescence intensity gradually weakens, accompanied by an obvious redshift. The Raman peak intensities decrease gradually, and the peaks disappear eventually with the pressure increasing. These spectral changes are attributed to the changes in the intramolecular conformation, that is, the strengthening of the weak C-H···O hydrogen bonds in TMOE molecules, which is caused by the twisted dihedral angle between the benzene ring and the carbon rigid plane of ethylene. Density functional theory simulation further confirms that the decreased dihedral angle could weaken Raman peak intensity, which is consistent with our experimental results.
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http://dx.doi.org/10.1021/acs.jpca.5b02362DOI Listing
September 2015

Organic Crystals with Near-Infrared Amplified Spontaneous Emissions Based on 2'-Hydroxychalcone Derivatives: Subtle Structure Modification but Great Property Change.

Angew Chem Int Ed Engl 2015 Jul 3;54(29):8369-73. Epub 2015 Jun 3.

State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Qianjin Street, Changchun (P. R. China).

A series of highly efficient deep red to near-infrared (NIR) emissive organic crystals 1-3 based on the structurally simple 2'-hydroxychalcone derivatives were synthesized through a simple one-step condensation reaction. Crystal 1 displays the highest quantum yield (Φf) of 0.32 among the reported organic single crystals with an emission maximum (λem) over 710 nm. Comparison between the bright emissive crystals 1-3 and the nearly nonluminous compounds 4-7 clearly gives evidence that a subtle structure modification can arouse great property changes, which is instructive in designing new high-efficiency organic luminescent materials. Notably, crystals 1-3 exhibit amplified spontaneous emissions (ASE) with extremely low thresholds. Thus, organic deep red to NIR emissive crystals with very high Φf have been obtained and are found to display the first example of NIR fluorescent crystal ASE.
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http://dx.doi.org/10.1002/anie.201503914DOI Listing
July 2015

The facile realization of luminescence based on one yellow emissive four-coordinate organoboron material.

Chem Commun (Camb) 2015 May;51(36):7701-4

State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China.

The orange emissive powders of a boron-containing compound generate red, green, and blue luminescence after compressing, heating, and volatile acid fuming, respectively. Thus, stimulus-induced emissions have been facilely realized based on one organic π-conjugated material for the first time, to the best of our knowledge.
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http://dx.doi.org/10.1039/c5cc01113bDOI Listing
May 2015

2-(2-Hydroxyphenyl)benzimidazole-based four-coordinate boron-containing materials with highly efficient deep-blue photoluminescence and electroluminescence.

Inorg Chem 2015 Mar 25;54(6):2652-9. Epub 2015 Feb 25.

State Key Laboratory of Supramolecular Structure and Materials, International Joint Research Laboratory of Nano-Micro Architecture Chemistry, College of Chemistry, Jilin University , Changchun 130012, P. R. China.

Two novel four-coordinate boron-containing emitters 1 and 2 with deep-blue emissions were synthesized by refluxing a 2-(2-hydroxyphenyl)benzimidazole ligand with triphenylborane or bromodibenzoborole. The boron chelation produced a new π-conjugated skeleton, which rendered the synthesized boron materials with intense fluorescence, good thermal stability, and high carrier mobility. Both compounds displayed deep-blue emissions in solutions with very high fluorescence quantum yields (over 0.70). More importantly, the samples showed identical fluorescence in the solution and solid states, and the efficiency was maintained at a high level (approximately 0.50) because of the bulky substituents between the boron atom and the benzimidazole unit, which can effectively separate the flat luminescent units. In addition, neat thin films composed of 1 or 2 exhibited high electron and hole mobility in the same order of magnitude 10(-4), as determined by time-of-flight. The fabricated electroluminescent devices that employed 1 or 2 as emitting materials showed high-performance deep-blue emissions with Commission Internationale de L'Eclairage (CIE) coordinates of (X = 0.15, Y = 0.09) and (X = 0.16, Y = 0.08), respectively. Thus, the synthesized boron-containing materials are ideal candidates for fabricating high-performance deep-blue organic light-emitting diodes.
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http://dx.doi.org/10.1021/ic502815qDOI Listing
March 2015

Exchange narrowing and exciton delocalization in disordered J aggregates: simulated peak shapes in the two dimensional spectra.

J Chem Phys 2013 Jul;139(3):034313

State Key Laboratory of Supramolecular Structure and Materials, Jilin University, 2699 Qianjin Street, Changchun 130012, People's Republic of China.

Delocalized excitons in elementary linear J aggregates of two-level molecules absorb a photon into the low-energy edge of an exciton band. Absorption of a second photon is blue-shifted as the lowest energy state is occupied. This setup of states leads to a double-peak feature in a set of two dimensional photon echo spectra for excitonic bands. The delocalization properties of excitons, thus, strongly affect the peak lineshapes and their relative amplitudes. Simulations of various two dimensional spectra of a linear J aggregate are presented and possible schemes to quantitatively characterize the peak profiles are suggested. This allows to relate observable peak lineshapes to the exciton delocalization.
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http://dx.doi.org/10.1063/1.4812927DOI Listing
July 2013

Theoretical investigation of electronic structure and charge transport property of 9,10-distyrylanthracene (DSA) derivatives with high solid-state luminescent efficiency.

Phys Chem Chem Phys 2013 Feb 15;15(7):2449-58. Epub 2013 Jan 15.

State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun 130012, PR China.

The electronic structure and charge transport property of 9,10-distyrylanthracene (DSA) and its derivatives with high solid-state luminescent efficiency were investigated by using density functional theory (DFT). The impact of substituents on the optimized structure, reorganization energy, ionization potential (IP) and electronic affinity (EA), frontier orbitals, crystal packing, transfer integrals and charge mobility were explored based on Marcus theory. It was found that the hole mobility of DSA was 0.21 cm(2) V(-1) s(-1) while the electron mobility was 0.026 cm(2) V(-1) s(-1), which were relatively high due to the low reorganization energies and high transfer integrals. The calculated results showed that the charge transport property of these compounds can be significantly tuned via introducing different substituents to DSA. When one electron-withdrawing group (cyano group) was introduced into DSA, DSA-CN exhibited hole mobility of 0.14 cm(2) V(-1) s(-1) which was on the same order of that of DSA. However, the electron mobility of DSA-CN decreased to 8.14 × 10(-4) cm(2) V(-1) s(-1) due to the relatively large reorganization energy and disadvantageous transfer integral. The effect of electron-donating substituents was investigated by introducing methoxy group and tertiary butyl into DSA. DSA-OCH(3) and DSA-TBU showed much lower charge mobility than DSA resulting from the steric hindrance of substituents. On the other hand, both of them exhibited balanced transport properties (for DSA-OCH(3), the hole and electron mobility was 0.0026 and 0.0027 cm(2) V(-1) s(-1); for DSA-TBU, the hole and electron mobility was 0.045 and 0.012 cm(2) V(-1) s(-1)) because of their similar transfer integrals for both hole and electron. DSA and its derivatives were supposed to be one of the most excellent emissive materials for organic electroluminescent applications because of their high charge mobility and high solid-state luminescent efficiency.
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http://dx.doi.org/10.1039/c2cp41876bDOI Listing
February 2013

Theoretical study of isomerism/phase dependent charge transport properties in tris(8-hydroxyquinolinato)aluminum(III).

J Phys Chem A 2011 Aug 3;115(33):9259-64. Epub 2011 Aug 3.

Fundamental Department, Chinese People's Armed Police Force Academy, Langfang 065000, Hebei, People's Republic of China.

The charge carrier transporting ability in the polymorphism of tris(8-hydroxyquinolinato)aluminum(III) (Alq(3)) has been studied using density functional theory (DFT) and Marcus charge transport theory. α- and β-Alq(3) composed of mer-Alq(3) molecules have stronger electron-transporting property (n-type materials) compared with their hole-transporting ability. In contrast, γ- and δ-Alq(3) formed by fac-Alq(3) molecules possess stronger hole-transporting character than their electron-transporting ability. The detailed theoretical calculations indicate the reason lies in the differences of HOMO and LUMO distribution states of the two kinds of isomers, and the different molecular packing modes of charge-transporting pathways for different phases.
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http://dx.doi.org/10.1021/jp202976mDOI Listing
August 2011

A multifunctional fluorescence probe for the detection of cations in aqueous solution: the versatility of probes based on peptides.

J Fluoresc 2011 Sep 11;21(5):1921-31. Epub 2011 May 11.

State Key Laboratory of Supramolecular Structure and Materials, Jilin University, No. 2699, Qianjin Street, Changchun 130012, China.

We synthesized a tetra-functional fluorescence probe based on dansyl and peptide motif, dansyl-Gly-Trp (DGT, 1), that efficiently bound several metal ions and showed distinguishing optical properties. The probe 1 could respond to Hg(2+) with enhanced and blue-shifted fluorescence emission but to Cu(2+) with obvious fluorescence quenching. In addition, 1 was sensitive to pH ranging from 2.0 to 5.0 and precipitated in the presence of Pb(2+) at neutral conditions. The combination of these intrinsic properties with the selective responses to different chemical inputs allows this system to be implemented as an ionic switch. Furthermore, 1 could penetrate the cell membrane and accumulated well in intracellular region. The underlying mechanisms of the probe to different kind of metal ion were explored successfully by using either (1)H NMR, NOESY, electron paramagnetic resonance (EPR) or FT-IR spectra. In addition, to investigate the binding model of 1/Hg(2+) and 1/Cu(2+), simulations were also performed by using density functional theory (DFT) and reasonable binding configurations were achieved for these two complexes.
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http://dx.doi.org/10.1007/s10895-011-0891-6DOI Listing
September 2011

π-π interaction of quinacridone derivatives.

J Comput Chem 2011 Jul 3;32(10):2055-63. Epub 2011 May 3.

State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun 130012, People's Republic of China.

The π–π stacking interactions play an important role in molecular assemblies of quinacridone derivatives (QAs). In our previous work (Sun et al., J Phys Chem A 2008, 112, 11382), we have shown that quinacridone derivatives can be self-associated as dimers in solution by means of NMR study. Herein, we perform theoretical studies on the molecular interaction in the dimers of QAs to illustrate π–π interactions in terms of their strength, geometrical preference, substituent effect, and physical nature. Density functional theory (DFT-D) was adopted to calculate potential energy surfaces. The detailed analysis on the intermolecular interaction in diversity of dimeric configurations reveals that the displaced conformations with specific geometries in both parallel and antiparallel stacking manners can be stabilized, which are in agreement with NMR experimental findings.
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http://dx.doi.org/10.1002/jcc.21782DOI Listing
July 2011

Bipolar host molecules for efficient blue electrophosphorescence: a quantum chemical design.

J Phys Chem A 2010 Jan;114(2):965-72

State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun 130012, PR China.

On the basis of density functional theory (DFT) calculations, a new series of bipolar host molecules for efficient blue electrophosphorescence devices are designed by linkage of hole-transporting moiety carbazole (CZ) and electron-transporting unit diphenylphosphoryl (ph(2)P horizontal lineO) to the core molecules with high triplet energies. The electronic structures in the ground states, cationic and anionic states, and lowest triplet states of the designed molecules have been studied with emphasis on triplet energies, spin density distributions, ionization potentials, electron affinities, and the influence of molecular topology. Designed bipolar host molecules possess the following features: (1) relatively higher highest occupied molecular orbital (HOMO) for hole injection and, relatively lower lowest unoccupied molecular orbital (LUMO) for electron injection; (2) HOMO and LUMO separation and localization in the respective hole- and electron-transporting moieties; (3) dramatic bond length changes in ionic states occurring at different parts of the bipolar molecules with respect to their neutral states; (4) keeping higher triplet energy. The DFT results provide deep insight into the nature of bipolar molecules and show that the designed molecules are feasible to meet the requirements of the host materials for blue triplet emissions.
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http://dx.doi.org/10.1021/jp904610sDOI Listing
January 2010

The origin of the improved efficiency and stability of triphenylamine-substituted anthracene derivatives for OLEDs: a theoretical investigation.

Chemphyschem 2008 Dec;9(17):2601-9

State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun 130012, PR China.

Herein, we describe the molecular electronic structure, optical, and charge-transport properties of anthracene derivatives computationally using density functional theory to understand the factors responsible for the improved efficiency and stability of organic light-emitting diodes (OLEDs) with triphenylamine (TPA)-substituted anthracene derivatives. The high performance of OLEDs with TPA-substituted anthracene is revealed to derive from three original features in comparison with aryl-substituted anthracene derivatives: 1) the HOMO and LUMO are localized separately on TPA and anthracene moieties, respectively, which leads to better stability of the OLEDs due to the more stable cation of TPA under a hole majority-carrier environment; 2) the more balanceable hole and electron transport together with the easier hole injection leads to a larger rate of hole-electron recombination, which corresponds to the higher electroluminescence efficiency; and 3) the increasing reorganization energy for both hole and electron transport and the higher HOMO energy level provide a stable potential well for hole trapping, and then trapped holes induce a built-in electric field to prompt the balance of charge-carrier injection.
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http://dx.doi.org/10.1002/cphc.200800513DOI Listing
December 2008

Theoretical characterization of a typical hole/exciton-blocking material bathocuproine and its analogues.

J Phys Chem A 2008 Sep 27;112(38):9097-103. Epub 2008 Aug 27.

State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun 130012, Jilin, People's Republic of China.

The structural, electronic, and carrier transport properties of bathocuproine (BCP), which is a typical hole/exciton-blocking material applied in organic light-emitting diodes (OLEDs), have been investigated based on density functional theory (DFT) and ab initio HF method. The detail characterizations of frontier electronic structure and lowest-energy optical transitions have been studied by means of time-dependent density functional theory (TD-DFT). Five BCP analogues, o-phenanthroline (1), 2,9-dimethyl-1,10-phenanthroline (2), 2,9-diphenyl-1,10-phenanthroline (3), 4,7-diphenyl-1,10-phenanthroline (4), and 2,9-bis(trifluoromethyl)-1,10-phenanthroline (5) have also been studied in order to select more suitable candidates of efficient hole-blocking materials. The calculated results showed that rigid planar structures, conjugate degrees, and substitute groups play crucial roles in the hole/exciton-blocking and electron-transport properties of these materials. The calculated geometries, ionization energies (IP), and energy gap between the singlet ground state and triplet excited state (E(T1)) were well in agreement with the experimental results. On the basis of the incoherent transport model, the calculated electron mobility of BCP is 1.79 x 10(-2) cm(2)/(V s), which is comparable to experimental results of 1.1 x 10(-3) cm(2)/(V s). The electron mobilities for compounds 1, 4, and 5 are 3.45 x 10(-2), 2.90 x 10(-2), and 1.40 x 10(-2) cm(2)/(V s), respectively. The calculated results indicated that compounds 1, 4, and 5 may be more effective hole/exciton-blocking materials than BCP.
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http://dx.doi.org/10.1021/jp804308eDOI Listing
September 2008

Cruciform oligo(phenylenevinylene) with a bipyridine bridge: synthesis, its rhenium(I) complex and photovoltaic properties.

Chem Commun (Camb) 2008 Sep 30(33):3912-4. Epub 2008 Jun 30.

State Key Laboratory for Supramolecular Structure and Materials, Jilin University, Changchun, PR China.

A cruciform-shaped oligo(phenylenevinylene) (OPV) with a phosphorescent rhenium(I) chromophore incorporated at the centre and grafted triphenylamines around the periphery was designed as a new organic photovoltaic material, in which the chelation of rhenium(I) to the cruciform successfully constructs a three-dimensional intramolecular charge transfer system and extends the exciton lifetime; as a result, the rhenium-OPV complex shows a power conversion efficiency almost two times that of the metal ion-free parent compound.
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http://dx.doi.org/10.1039/b804995eDOI Listing
September 2008

Theoretical studies of blue-emitting iridium complexes with different ancillary ligands.

J Phys Chem A 2008 Sep 15;112(36):8387-93. Epub 2008 Aug 15.

State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun 130012, People's Republic of China.

The structural and electronic properties of two heteroleptic iridium complexes Ir(dfppy)2(pic) (FIrpic) and Ir(dfppy)2(acac) (FIracac) have been investigated theoretically, where dfppy = 2-(2,4-difluorophenyl) pyridine, pic = picolinic acid, and acac = acetoylacetonate. The geometries of ground and excited states are optimized at PBE0/LANL2DZ and CIS/LANL2DZ levels, respectively. Time-dependent density functional theory (TDDFT) method is employed to explore the absorption and emission properties. In the ground state, the highest-occupied molecular orbital has a significant mixture of metal Ir(d) and dfppy(pi), the lowest-unoccupied orbital locates primarily on pi* of pic for FIrpic and pi* of dfppy for FIracac. The luminescence of each complex originates from the lowest triplet excited state, which is assigned to the mixing of metal-to-ligand charge transfer and intraligand charge transfer characters. The effects of ancillary ligands pic and acac on absorption and emission spectra are observed by analysis of TDDFT results. The connection between the nature of excited states and the behavior of the complexes with different ancillary ligands is elucidated.
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http://dx.doi.org/10.1021/jp8026429DOI Listing
September 2008

Thermal cycloaddition facilitated by orthogonal pi-pi organization through conformational transfer in a swivel-cruciform oligo(phenylenevinylene).

Angew Chem Int Ed Engl 2007 ;46(18):3245-8

Key Laboratory for Supramolecular Structure and Materials of the Ministry of Education, Jilin University, Changchun 130012, PR China.

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http://dx.doi.org/10.1002/anie.200603878DOI Listing
July 2007
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