Synthesis, structure, and condensed-phase reactivity of [Ag3(μ3-H)(μ3-BH4)LPh3](BF4) (LPh = bis(diphenylphosphino)amine) with CS2. Issue 41 (3rd October 2018)

• Record Type: Journal Article
• Authors: Ma, Howard Z.; White, Jonathan M.; Mulder, Roger J.; Reid, Gavin E.; Canty, Allan J.; O'Hair, Richard A. J.
• Is Part Of: Dalton transactions. Volume 47:Issue 41(2018)
• Page Start: 14713
• Page End: 14725
• Publication Date: 2018-10-03
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c8dt02437e
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Electrospray ionisation mass spectrometry (ESI-MS) was used to monitor the reaction of AgBF4, bis(diphenylphosphino)amine (dppa = (Ph2 P)2 NH = L Ph ) and NaBH4 in acetonitrile. Abstract : Electrospray ionisation mass spectrometry (ESI-MS) was used to monitor the reaction of AgBF4, bis(diphenylphosphino)amine (dppa = (Ph2 P)2 NH = L Ph ) and NaBH4 in acetonitrile and thereby direct the synthesis of the silver nanocluster [Ag3 (μ3 -H)(μ3 -BH4 )L Ph 3 ](BF4 ), 3b·BF4, formed via reaction of AgBF4, bis(diphenylphosphino)amine (dppa = (Ph2 P)2 NH = L Ph ) and NaBH4 in acetonitrile. The X-ray structure of3b·BF4 highlights that the cation adopts a planar trinuclear Ag3 geometry surrounded by three dppa ligands and coordinated on the bottom face by a μ3 -hydride and on the top face by a μ3 -BH4 . The solution phase structure of3b·BF4 was characterised by multinuclear NMR and DOSY NMR, which showed that the borohydride anion remains bound in the [Ag3 (μ3 -H)(μ3 -BH4 )L Ph 3 ] + cluster cation in solution. ESI-MS and in situ 1 H and HSQC NMR spectroscopy reveals that3b·BF4 reacts with CS2 in solution at the BH4 site to yield [Ag3 (H)(S2 CH)L Ph 3 ] +, 4b, which has to date eluded structural characterisation via X-ray crystallography due to lack of formation of suitable crystals. The gas-phase ion chemistry of [Ag3 (H)(S2 CH)L Ph 3 ] + was examined under multistage mass spectrometry conditions using collision-induced dissociation (CID) and compared to that of the previously examined copper analogue, [Cu3 (H)(S2 CH)L Ph 3 ] + . While both cluster cations fragment via ligand loss, the CID spectra of the resultant [M3 (H)(S2 CH)L Ph 2 ] + are different. Unlike [Cu3 (H)(S2 CH)L Ph 2 ] +, which solely undergoes loss of thioformaldehyde to give [Cu3 (S)L Ph 2 ] +, [Ag3 (H)(S2 CH)L Ph 2 ] + gives a richer CID spectrum with fragmentation channels that include ligand loss, CH2 S loss and reductive elimination of dithioformic acid. DFT calculations exploring rearrangement and fragmentation of the model systems [M3 (H)(S2 CH)L Me 2 ] + ((Me2 P)2 NH = dmpa = L Me ) were used to suggest plausible mechanisms and examine the energetics of the three competing channels: ligand loss, CH2 S loss and reductive elimination of dithioformic acid.