Synthesis and X-ray Crystal Structure of Polymeric and Dimeric Copper(I) Cyanide Complexes Incorporating A Bicyclic Guanidine Ligand
journal contribution
posted on 2023-06-07, 21:20authored byMartyn Coles, Peter B Hitchcock
1,3,4,6,7,8-Hexahydro-2H-pyrimido[1,2-a]pyrimidine (hppH) reacts with copper(I) cyanide to afford the polymeric chain [(hppH)CuCN]¿ (1), consisting of distorted trigonal planar copper atoms linked by cyanide bridges. Attempts to isolate molecular species by repeating the reaction in the presence of triphenylphosphine gave a dimeric complex of the general formula [Cu2(CN)2(PPh3)4(hppH)] (2). The solid-state structure of 2 is consistent with a zwitterionic complex, comprising of [Cu(+)(PPh3)2(hppH)] and [Cu(¿)(CN)2(PPh3)2] metal centres, linked by a cyanide bridge. Variable temperature NMR studies suggest that the formation of higher oligomers may occur in solution at low temperature.