A second solvatomorph of poly[[μ4- N, N'-(1,3,5-oxadiazinane-3,5-di-yl)bis-(carbamoyl-methano-ato)]nickel(II)dipotassium]: crystal structure, Hirshfeld surface analysis and semi-empirical geometry optimization

Abstract

The title compound, poly[tri-aqua-bis-[μ₄-N,N'-(1,3,5-oxadiazinane-3,5-di-yl)bis(carbamoyl-methano-ato)]dinickel(II)tetra-potassium], [K₄Ni₂(C₇H₆N₄O₇)₂(H₂O)₃] _n , is a second solvatomorph of poly[(μ₄-N,N'-(1,3,5-oxadiazinane-3,5-di-yl)bis-(carbamoyl-methano-ato)nickel(II)dipotassium] reported previously [Plutenko et al. (2021 ▸). Acta Cryst. E77, 298-304]. The asymmetric unit of the title compound includes two structurally independent complex anions [Ni(C₇H₆N₄O₇)]^2-, which exhibit an L-shaped geometry and consist of two almost flat fragments perpendicular to one another: the 1,3,5-oxadiazinane fragment and the fragment including other atoms of the anion. The central Ni atom is in a square-planar N₂O₂ coordination arrangement formed by two amide N and two carboxyl-ate O atoms. In the crystal, the title compound forms a layered structure in which layers of negatively charged complex anions and positively charged potassium cations are stacked along the a-axis direction. The polymeric framework is stabilized by a system of hydrogen-bonding inter-actions in which the water mol-ecules act as donors and the carb-oxy-lic, amide and water O atoms act as acceptors.

Keywords: Hirshfeld surface analysis; SHAPE analysis; crystal structure; hydrazide-based ligand; nickel(II) complex; pseudomacrocyclic ligand; semi-empirical geometry optimization; template reaction.