Hydride Transfer to Gold: Yes or No? Exploring the Unexpected Versatility of Au···H‐M Bonding in Heterobimetallic Dihydrides

Rocchigiani, Luca, Klooster, Wim, Coles, Simon J., Hughes, David, Hrobarik, Peter and Bochmann, Manfred (2020) Hydride Transfer to Gold: Yes or No? Exploring the Unexpected Versatility of Au···H‐M Bonding in Heterobimetallic Dihydrides. Chemistry - A European Journal, 26 (37). pp. 8267-8280. ISSN 0947-6539

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Abstract

The potential for coordination and H-transfer from Cp2MH2 (M = Zr, W) to gold(I) and gold(III) complexes was explored in a combined experimental and computational study. [(L)Au]+ cations react with Cp2WH2 giving [(L)Au(κ2-H2WCp2)]+ (L = IPr ( 1 ), cyclic (alkyl)(amino)carbene ( 2) , or phosphines PPh3 (3) and Dalphos-Me (4) [IPr = 1,3-bis(diisopropylphenyl)imidazolylidene; Dalphos-Me = di(1-adamantyl)-2-(dimethylamino)phenyl-phosphine], while [Au(DMAP)2]+ (DMAP = p-dimethylaminopyridine) affords the C2-symmetric [Au(κ-H2WCp2)2]+ (5) . The Dalphos complex 4 can be protonated to give the bicationic adduct 4H , showing Au(I)…H+-N hydrogen bonding. The gold(III) Lewis acid [(C^N-CH)Au(C6F5)(OEt2)]+ binds Cp2WH2 to give an Au-H-W σ-complex. By contrast, the pincer species [(C^N^C)Au]+ adds Cp2WH2 by a purely dative W→Au bond, without Au···H interaction. The biphenyl-based chelate [(C^C)Au]+ forms [(C^C)Au(µH)2WCp2]+, with two 2-electron-3-centre W-H…Au interactions and practically no Au-W donor acceptor contribution. In all these complexes strong but polarised W-H bonds are maintained, without H-transfer to gold. On the other hand, the reactions of Cp2ZrH2 with gold complexes led in all cases to rapid H-transfer and formation of gold hydrides. Relativistic DFT calculations were used to rationalize the striking reactivity and bonding differences in these heterobimetallic hydride complexes along with an analysis of their characteristic NMR parameters and UV-Vis absorption properties.

Item Type: Article
Uncontrolled Keywords: bridging ligands,density functional calculations,gold,hydrides,tungsten,catalysis,organic chemistry ,/dk/atira/pure/subjectarea/asjc/1500/1503
Faculty \ School: Faculty of Science > School of Chemistry
Related URLs:
Depositing User: LivePure Connector
Date Deposited: 29 Feb 2020 08:35
Last Modified: 21 Sep 2020 00:01
URI: https://ueaeprints.uea.ac.uk/id/eprint/74346
DOI: 10.1002/chem.202000016

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