Synthesis, crystal structure and magnetic behavior of a croconato bridged Cu(ii) complex: effect of C–H⋯O interaction in controlling the coordination bond formation in organic–inorganic hybrid

A 2-D croconato bridged complex of Cu(II), [{Cu(C5O5)(bpee)}·0.5H2O]n (1) [bpee, trans-1,2-bis(4-pyridyl)ethylene] has been synthesized by in situ hydrothermal reaction and characterized by X-ray diffraction analysis, variable temperature magnetic susceptibility measurement and EPR study. The structure determination reveals that the adjacent 2-D sheets are extended to 3-D supramolecular architecture through π–π and trifurcated C–H⋯O interactions, which inhibit the oxygen atom of croconate from forming the usual bridging mode.