Diversity of polymeric structures for copper complexes of the extended-reach siloxypyridine ligands [iPr2SiO(CH2)npy]2O (n=0, 1, 3)

The structures of six copper(II) complexes formed by the siloxypyridine ligands [iPr2SiO(CH2)npy]2O (n=0, 1, 3), and of a copper(I) iodide complex of (iPr2SiOpy)2O, have been determined. In all cases polymeric structures are produced, but with a diversity of structural types. Chains of 24-membered macrocycles are present in Cu[(iPr2SiOpy)2O]2Br2. The structure of Cu4[(iPr2SiOpy)2O]2I4 also comprises chains of macrocycles but with Cu4I4 polyhedra as the connecting ‘node’ points. In [Cu2(OAc)4{(iPr2SiOCH2py)2O}] dinuclear Cu2(OAc)4 units are linked into chains by the (iPr2SiOCH2py)2O ligands. Chains of 28-membered macrocycles are formed by [Cu{(iPr2SiOCH2py)2O}2(H2O)2](NO3)2, with further cross-linking by hydrogen bonding between the aqua ligands and the nitrate anions. Two crystalline forms of [Cu2{(iPr2SiOCH2py)2O}3Br4] were obtained, one comprising ‘tapes’ of contiguous 28- and 112-membered macrocycles and the other interpenetrating folded sheets of 84-membered macrocycles. Chains of 36-membered macrocycles are formed by [Cu{(iPr2SiOCH2CH2CH2py)2O}2(NO3)2].