9 results match your criteria prepare carboranes

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Metal-catalyzed cross-coupling chemistry with polyhedral boranes.

Chem Commun (Camb) 2019 Jan;55(4):430-442

Department of Chemistry & Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, California 90095, USA.

Over the past several decades, metal-catalyzed cross-coupling has emerged as a very powerful strategy to functionalize carbon-based molecules. More recently, some of the cross-coupling methodologies have been adapted to inorganic compounds including boron-rich clusters. The development of this chemistry relies on the ability to synthesize halogenated boron-rich clusters which can serve as electrophilic cross-coupling partners with nucleophilic substrates in the presence of a metal catalyst. Read More

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January 2019

Chelating N-heterocyclic carbene-carboranes offer flexible ligand coordination to Ir, Rh and Ru: effect of ligand cyclometallation in catalytic transfer hydrogenation.

Dalton Trans 2016 Oct;45(40):15818-15827

School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK.

Imidazolium salts linked by an ethyl tether to closo-dicarbadodecaboranes were reacted with [IrCp*Cl], [RhCp*Cl] or [Ru(p-cymene)Cl] in the presence of AgO to prepare complexes of the type [MCp*(NHC)Cl] (M = Ir, Rh; NHC = N-heterocyclic carbene) or [Ru(p-cymene)(NHC)Cl]. When the NHC contained an N-Bu substituent, C-H activation of the Bu and subsequent alkyl coordination was observed at Ir. Coordination of the closo-dicarbadodecaborane moiety to Ir was possible to give 7-membered metallacycles, coordinated through the carbenic carbon of the NHC and either a carbon atom or a boron atom of the carborane. Read More

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October 2016

Supercarborane radical anions with 2n + 3 electron counts: a combined experimental and theoretical study.

Inorg Chem 2015 Feb 26;54(4):1965-73. Epub 2015 Jan 26.

Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong , Shatin, New Territories, Hong Kong, China.

The synthesis, structure, spectroscopic characterization, and density functional theory (DFT) calculations of several 13-vertex carborane radical anions were described. Reactions of 13-vertex closo-carboranes with 1 equiv of finely cut sodium metal in tetrahydrofuran at room temperature afforded the corresponding sodium salts of carborane radical anions as dark-red crystals in very good yield. They represent a rare class of clusters having 2n + 3 framework electrons, which lie between the two well-established and abundant closed 2n + 2 (closo) and open 2n + 4 (nido) skeleton systems. Read More

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February 2015

High yielding synthesis of carboranes under mild reaction conditions using a homogeneous silver(I) catalyst: direct evidence of a bimetallic intermediate.

Angew Chem Int Ed Engl 2014 May 2;53(20):5156-60. Epub 2014 Apr 2.

Department of Chemistry and Chemical Biology, McMaster University, 1280 Main St W., Hamilton, Ont., L8S 4M1 Canada; Department of Chemistry, Faculty of Science, Tanta University, 31527 Tanta (Egypt).

Methods used to prepare functionalized carboranes generally require heating to high temperatures, and thus limits the range of derivatives which can be prepared directly from alkynes. We show here that by using a homogeneous silver(I) catalyst it is now possible to prepare carboranes in good to excellent yield at temperatures below 40 °C, including at room temperature. The process is general and provides an important new synthetic strategy for the preparation of functionalized boron clusters. Read More

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Preparation and evaluation of carborane-derived inhibitors of prostate specific membrane antigen (PSMA).

Dalton Trans 2014 Apr;43(13):4950-61

Department of Chemistry and Chemical Biology, McMaster University, 1280 Main St. West, Hamilton, Ont., CanadaL8S 4M1.

A series of C-hydroxy carborane derivatives of (S)-2-(3-((S)-5-amino-1-carboxypentyl)ureido)-pentanedioic acid were prepared as a new class of boron rich inhibitors of prostate specific membrane antigen (PSMA), which is overexpressed on prostate cancer tumours and metastases. Closo-, nido- and iodo-carborane conjugates were prepared and screened in vitro where the water soluble iodinated cluster had the highest affinity with an IC50 value (73.2 nM) that was comparable to a known PSMA inhibitor 2-(phosphonomethyl)-pentanedioic acid (PMPA, 63. Read More

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Synthesis, characterisation, and biodistribution of radioiodinated C-hydroxy-carboranes.

Chemistry 2012 Aug 16;18(35):11071-8. Epub 2012 Jul 16.

Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario, Canada.

The synthesis, radiolabelling and biodistribution of iodinated C-hydroxy-nido-carborane ligands is described. Microwave heating by using NaF in aqueous ethanol was used to prepare {sodium [7-hydroxy-7,8-dicarba-nido-undecaborate], nido-carboranol} and {sodium [7-hydroxy-7,8-dicarba-nido-undecaborate-8-carboxylic acid], nido-salborin} in 97 and 90 % yield, respectively. Radioiodination of these nido-carboranes was completed by using both (125)I and (123)I, and the products were obtained in high radiochemical purity (>99 %) and yield (72 to 87 %). Read More

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Microwave-assisted synthesis of 3,1,2- and 2,1,8-Re(I) and 99mTc(I)-metallocarborane complexes.

Inorg Chem 2006 Jul;45(15):5727-9

Departments of Chemistry and Medical Physics & Applied Radiation Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4M1.

Microwave heating was used to prepare eta5-rhenium carborane complexes in aqueous reaction media. For carboranes bearing sterically demanding substituents, isomerization of the cage from 3,1,2 to 2,1,8 derivatives occurred concomitantly with complexation. Microwave heating was equally effective at the tracer level using technetium-99m, affording access to a new class of synthons for designing novel molecular imaging agents. Read More

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Synthesis, NMR, and X-ray crystallographic analysis of C-hydrazino-C-carboxycarboranes: versatile ligands for the preparation of BNCT and BNCS agents and (99m)Tc radiopharmaceuticals.

Inorg Chem 2002 May;41(10):2731-7

Department of Chemistry, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1, Canada.

Protected hydrazine derivatives of ortho-, meta-, and para-carboranes were synthesized in good to excellent yields by reacting the mono-lithio salts of the respective carboranes with di-tert-butyl azodicarboxylate (DBAD). Subsequent deprotonation of the remaining carborane CH group, followed by the addition of CO(2)(g), resulted in the formation of bifunctional C-hydrazino-C-carboxycarboranes in good to excellent overall yields. Crystal structures of the monosubstituted ortho-carborane, 1-[(N,N'((tert-butyloxy)carbonyl)hydrazino)]-1,2-dicarba-closo-dodecaborane (8) [a = 21. Read More

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Carboranes as ligands for the preparation of organometallic Tc and Re Radiopharmaceuticals. Synthesis of [M(CO)(3)(eta-2,3-C(2)B(9)H(11))](-) and rac-[M(CO)(3)(eta-2-R-2,3-C(2)B(9)H(10))](-) (M = Re, (99)Tc; R = CH(2)CH(2)CO(2)H) from [M(CO)(3)Br(3)](2-).

Inorg Chem 2002 Feb;41(4):628-30

Department of Chemistry, McMaster University, Hamilton, Ontario, Canada L8S 4M1.

A new and high yielding method for the synthesis of [M(CO)(3)(eta(5)-2,3-C(2)B(9)H(11))](-) and the bifunctional metal complexes, rac-[M(CO)(3)(eta(5)-2-R-2,3-C(2)B(9)H(10))](-) (R = CH(2)CH(2)CO(2)H), from [M(CO)(3)Br(3)](2)(-) (M = Re, (99)Tc) was developed. The general approach entailed the addition of nido-[(C(2)B(9)H(12))(-)], or the acid substituted analogue, to [M(CO)(3)Br(3)](2)(-) (M = Re, (99)Tc) in the presence of TlOEt in THF. It was also possible to prepare the reported products in water using sodium carbonate in place of TlOEt. Read More

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February 2002
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