title: An unusual co-crystal [(μ2-dcpm)Ag2(μ2-O2CH)(η2-NO3)]2·[(μ2-dcpm)2Ag4(μ2-NO3)4] and its connection to the selective decarboxylation of formic acid in the gas phase.
abstract: ESI/MS of an acetonitrile solution containing a mixture of AgNO3:  bis(dicyclohexylphosphino)methane (dcpm, L) : NaO2CH in a molar ratio of 2 : 1 : 1 gave an abundant peak due to [LAg2(O2CH)]+and a minor peak assigned as [L2Ag4(O2CH)3]+. When this acetonitrile solution was frozen and layered with diethyl ether and left undisturbed for six days, crystalline material suitable for X-ray crystallography was identified and separated from amorphous solids. Single crystal X-ray diffraction revealed an unusual co-crystal consisting of two discrete tetranuclear silver clusters [(μ2-dcpm)Ag2(μ2-O2CH)(η2-NO3)]2·[(μ2-dcpm)2Ag4(μ2-NO3)4]. While all of the coordinated formates in [LAg2(O2CH)]+and [L2Ag4(O2CH)3]+can be decarboxylated in the gas-phase under conditions of collision induced dissociation, only the hydride [LAg2(H)]+thus formed reacts with formic acid via protonation and liberation of H2to regenerate to formate, thereby closing a catalytic cycle for the selective decomposition of formic acid.
authors.affiliation: School of Chemistry and Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, Melbourne, Victoria 3010, Australia. rohair@unimelb.edu.au.
authors.forename: Athanasios
authors.initials: A
authors.lastname: Zavras
authors.affiliation: School of Chemistry and Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, Melbourne, Victoria 3010, Australia. rohair@unimelb.edu.au.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: White
authors.affiliation: School of Chemistry and Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, Melbourne, Victoria 3010, Australia. rohair@unimelb.edu.au.
authors.forename: Richard A J
authors.identifier: http://orcid.org/0000-0002-8044-0502
authors.initials: RA
authors.lastname: O'Hair
mesh_terms: D056831:Coordination Complexes / Q000737:chemistry*; D003460:Crystallization; D018360:Crystallography, X-Ray; D005561:Formates / Q000737:chemistry*; D005740:Gases; D008958:Models, Molecular; D012834:Silver / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D056831:Coordination Complexes; D005561:Formates; D005740:Gases; C030544:formic acid; D012834:Silver