CRYSTAL STRUCTURE OF A NEW COORDINATION POLYMER, {[Ni₂Cl₂(L)(CH₃OH)₂(H₂O)2]Cl₂} _n , FROM X-RAY POWDER DATA. A. Neels, B. Mathez Neels and H. Stoeckli-Evans, Département de Chimie-Physique II, Université de Neuchâtel, Switzerland. A. Clearfield and D. M. Poojary, Department of Chemistry, Texas A & M University, USA.

Coordination metal complexes with polymeric structures are of special interest in the development of new materials. Molecular ferromagnets and non-linear optical materials are the most important applications of such coordination polymers.

2,5-Bis(2-pyridyl)pyrazine (L) has been used as molecular bridge between metal centers. Some binuclear complexes and a two-dimensional polymer with 3d transition metals are characterized by their single-crystal X-ray structure [1].

[[Ni₂Cl₂(L)(CH₃OH)₂(H₂O)2]Cl₂} _n (1), a new one-dimensional coordination polymer, was obtained in micro-crystalline form. The structure was determined ab initio from X-ray powder diffraction data. The compound belong to the triclinic space group P1 with a = 8.7014(4)Å, b = 10.1465(5)Å, c = 8.0303(3)Å, [[alpha]] = 116.095(2)deg.,

[[beta]] = 112.713(3)deg., [[gamma]]= 64.056(3)deg.. The final agreement factors are R_wp = 0.124, R_p = 0.095, and R_F = 0.045

The octahedral coordination of the nickel atom is achieved by two nitrogens of the ligand 2,5-bis(2-pyridyl)pyrazine, two chlorines and two oxygens of the coordinated solvent molecules. The bridging nature of chloride ions and bis-bidentate ligands (L) leads to a one-dimensional polymer.

[1] Neels,A., Stoeckli-Evans,H.; Escuer,A.; Vicente,R.; Inorg. Chem. 34(1995) 1964.