A sulfur-templated Ni–Ni′ coordination polymer that relies on a polarizable nickel nitrosyl hub

Abstract

The templating properties of a diaza-nickel-cis-dithiolate towards triphenylphosphine gold(I), yielding a transoid [Ni(N₂S₂)·2Au(PPh₃)] complex (T. A. Pinder, S. K. Montalvo, A. M. Lunsford, C.-H. Hsieh, J. H. Reibenspies and M. Y. Darensbourg, Dalton Trans., 2014, 43, 138–144) suggested that a suitable analogue of d¹⁰-Au(I), i.e., {Ni(NO)}¹⁰, could generate a tetrahedral nickel node for a [Ni(N₂S₂)·2Ni(NO)(X)]_n coordination polymer. Monomeric precursors, derived from Feltham's [(Ph₃P)₂Ni(NO)(Cl)] (R. D. Feltham, Inorg. Chem., 1964, 3, 116–119) produced the bidentate/sulfur-chelated [Ni(N₂S₂)·Ni(NO)(X)] species with loss of PPh₃. Exchange of Cl⁻ by azide, N₃⁻, in the {Ni(NO)}¹⁰ synthon led to the balance of electrophilicity at Ni(NO) and non-covalent (H-bonding and van der Waals) interactions that stabilized the extended chain of bridging sulfurs, in transoid connectivities, between a square planar Ni^II and a tetrahedral Ni, the latter within the electronic and spin-delocalized {Ni(NO)}¹⁰ system. This study defines a new path that creates coordination polymers using metallodithiolates, the success of which, in this case, depends on the highly polarizable {Ni(NO)}¹⁰ unit.