Ligand‐Field Control and Hydrogen Bonding as Design Elements in the Assembly and Crystallization of Poly(azolyl)borate‐Metal Complexes: Chelate Complexes Versus Coordination Polymers and Symmetrical Versus Distorted Grid Sheets

Abstract

Abstract The 1‐ and 2‐D coordination polymers [Mn{HB(C 2 H 2 N 3 ) 3 } 2 (H 2 O) 2 ].4H 2 O ( 11 ) and [Ni{H 2 B(CHN 4 ) 2 } 2 ‐(NH 3 ) 2 ] ( 13 ), respectively, and the chelate complex [Ni{H 2 B(C 2 H 2 N 3 ) 2 } 2 (H 2 O) 2 ] · 2H 2 O ( 12 ) were synthesized and structurally characterized. The compounds contain ambidentate poly(azolyl)borato ligands (azolyl = triazolyl or tetrazolyl), which can chelate or bridge metal centers. The metal–ligand structures in 11 – 13 differ from the known coordination modes of the poly(azolyl)borates towards other metal centers. We describe how a change in the metal and/or the conditions of crystallization affects the ligand‐field stabilization energy and favors one type of nitrogen donor atom over the other for the poly(triazolyl)borato ligands. The crystal structures of 11 and 12 contain additional water of crystallization; this leads to hydrogen‐bonded solvent substructures. In the case of the bis(triazolyl)borato ligands. The crystal structures of 11 and 12 contain additional water of crystallization; this leads to hydrogen‐bonded solvent substructures. In the case of the bis(tetrazolyl)borato ligand the water substructure is shown to function as a “reinforcing bar” that symmetrizes the metal–ligand grid sheet.