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(CzH,N3)3},(H20),1 ' 4H,O (11) and [Ni{H,B(CHN,)2},-(NH3),] (13), respectively, and the chelate 2 H 2 0 (12) were synthesized and structurally characterized. The compounds contain ambidentate poly(azoly1)borato ligands (azolyl = triazolyl or tetrazolyl), which can chelate or bridge metal centers. The metal -ligand structures in 11 -13 difcomplex "i~H2B(CZH,N,),J,(H20~21~ fer from the known coordination modes of the poly(azoly1)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(triazoly1)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(tetrazoly1)borato ligand the water substructure is shown to function as a "reinforcing bar" that symmetrizes the metal-ligand grid sheet.

Metal derivatives of tetrazoles

“…132 Apparently, spectroscopic data alone are inadequate to draw this conclusion, as the vibration frequency of the C=S fragment bound to nitrogen atoms has not been reliably assigned as yet. 316 A number of MT based on tetrazolyldihydroborate anions have been synthesised; they were formed as salts 207 338 341 ± 343 The reaction of compound 208 with nickel(II) 342 and copper(II) 343 salts in water results in loose amorphous precipitates, which can be dissolved in ammonia and then crystallised as polymeric complexes [M{H 2 B(CHN 4 ) 2 } 2 (NH 3 ) 2 ] n (211; M = Cu, Ni). 341,342 The structures of the resulting complexes were investigated by various spectroscopic methods and X-ray diffraction.…”

“…316 A number of MT based on tetrazolyldihydroborate anions have been synthesised; they were formed as salts 207 338 341 ± 343 The reaction of compound 208 with nickel(II) 342 and copper(II) 343 salts in water results in loose amorphous precipitates, which can be dissolved in ammonia and then crystallised as polymeric complexes [M{H 2 B(CHN 4 ) 2 } 2 (NH 3 ) 2 ] n (211; M = Cu, Ni). 341,342 The structures of the resulting complexes were investigated by various spectroscopic methods and X-ray diffraction. It was shown 338 that the dihydrobis(1-methyl-5-thiotetrazol-4-yl)borate anion is coordinated as a bidentate ligand (k 2 -S,S) in complex 209a and as a tridentate ligand (k 3 -S,S,HB) in complex 209b, i.e., rather strong Ni_H7B interaction is manifested.…”

Spin Crossover Studies on Bis{hydro‐tris(1,2,4‐triazolyl)borato}iron(II)

“…Secondly, the water matrix may also slightly modify the energy separation between the low-and high-spin state through (exodentate) N´´´H±O bonding which in turn influences slightly the ligand-field strength of the nitrogen donor atoms. The existence of such N´´´H±O hydrogen bridge bonding has been proven by the single-crystal X-ray structures of 1 and related molecules which showed the incorporation of six water molecules of crystallization, two of which were hydrogen bonded to the complex fragment [14,17].…”

“…Magnetic dilution was achieved by cocrystallization of 1 with the isostructural diamagnetic zinc complex [14] from a solution containing both Fe 2+ and Zn 2+ ions.…”

An Unusual Hydrogen-Bonded Network Associated with Metal-Organic Chains: Structure and Crystal Packing of the Coordination Polymer [Cd(terephthalate)(H2O)3].4H2O

“…The molecular recognition phenomena responsible for the assembly of these polymers and the inherent beauty of their crystal structures are additional factors attracting workers to this ®eld. For instance, aromatic %±% interactions (Goodgame et al, 1995), host±guest solvent interactions (Janiak, Scharmann, Gunther et al, 1995) or hydrogen bonding (Mao et al, 1996;Bertelli et al, 1997;Yaghi et al, 1996) can play an important role in the stabilization of coordination polymers.…”