The formation of supramolecular arrays in copper sulfimide complexes via aerial CO2 fixation; the X-ray crystal structures of [Cu(Ph2SNH)4]2(HCO3)2(trans-O2CCHCHCO2)·4H2O, Cu(Ph2SNH)2(η2-CO3) and Cu(Ph2SNH)2(η2-CO3)·H2O

Abstract

Copper fumarate reacts with Ph₂SNH, 1, in water–methanol, in the presence of air, to give [Cu(Ph₂SNH)₄]₂(HCO₃)₂(trans-O₂CCHCHCO₂)(H₂O)₄, 2. X-Ray crystallography reveals that within the structure of 2 the sulfimide N–H groups are linked into hydrogen-bonded arrays by the C–O units of both the fumarate anion and of the [(HCO₃)₂]²⁻ dimer (which results from fixation of aerial CO₂). A similar reaction using copper sulfate results in Cu(Ph₂SNH)₂(η²-CO₃), 3, in ca. 10% yield; higher yields may be obtained by addition of Na₂CO₃ to the starting mixture. The structure of 3 again consists of an array, in this case generated by interaction of the sulfimides with the uncoordinated C–O of the carbonate ligand. The hydrate Cu(Ph₂SNH)₂(η²-CO₃)·H₂O, 3a, can also be crystallised and reveals a honeycomb structure generated by hydrogen-bond linkages from water molecules.