(Acetato-κO)aqua(1H-imidazole- N³)(picolinato- κ²N,O)copper (II) 0.87-hy-drate: a Z' > 1 structure

Abstract

The crystal structure of the title compound, [Cu(C₆H₄NO₂)(C₂H₃O₂)(C₃H₄N₂)(H₂O)]•0.87H₂O, has a square-pyramidal-coordinated Cu^II centre (the imidazole is trans to the picolinate N atom, the acetate is trans to the picolinate –CO₂ group and the aqua ligand is in a Jahn-Teller-elongated apical position) and has two symmetry-independent mol¬ecules in the unit cell (Z' = 2), which are connected through complementary imidazole-picolinate N-H O hydrogen bonding. The two partially occupied solvent water mol¬ecules are each disordered over two positions. The disordered solvent water mol-ecules, together with pseudo¬symmetry elements, support the notion that a crystal structure with multiple identical chemical formula units in the structural asymmetric unit (Z' > 1) can represent a crystal `on the way', that is, a kinetic intermediate form which has not yet reached its thermodynamic minimum. Neighbouring mol¬ecules form π-π stacks between their imidazole and picolinate N-hetero¬cycles, with centroid-centroid distances in the range 3.582 (2)-3.764 (2) Å.