Self-assembly of Pd(II) pyrazolyl complexes to 1-D hydrogen-bonded coordination polymers

This work describes the synthesis and characterization of two novel Pd(II) pyrazolyl complexes of the type [PdX2(HdmPz)2]n {X=SCN− (1), N3 − (2); HdmPz=3,5-dimethylpyrazole} that self-assemble through NH⋯NCS or NH⋯NNN hydrogen bonds to yield infinite one-dimensional chains, as confirmed by single crystal X-ray study on 1. The expected solid state polymeric structure for 2 is slowly broken up in CHCl3 solution, leading to an equilibrium mixture of cis and trans-[Pd(N3)2(HdmPz)2] monomers, as demonstrated by time-dependent IR and NMR studies.