Tungsten Nitride Chloride-P0Cl3 Solvate, Preparation, IR, Crystal Structure

W o l f g a n g L i e b e l t , K u r t D e h n i c k e Fachbereich Chemie der Philipps-Universität Marburg, D-3550 Marburg/Lahn Z. Naturforsch. 84b, 942-948 (1979); eingegangen am 26. März 1979 Tungsten Nitride Chloride-P0Cl3 Solvate, Preparation, IR, Crystal Structure Tungsten nitride chloride-POCl3 solvate, [WNC13 • P0C13]4 • 2 POCl3 is prepared by the reaction of WNCI3 with excess POCI3. With equimolar amounts of POCI3 in dichloromethane suspension the complex [WNCI3 • P0C13]4 • 2 CH2CI2 is formed, which is easily decomposed leaving pure [WNCI3 • POCl3]4. The IR spectra of these complexes were recorded and assigned. A new preparative route to WNCI3 from tungsten hexachloride and iodine azide is described. [WNCI3 • P0C13]4 • 2 POCl3 crystallizes in the triclinic space group P 1 with two tetrameric units per unit cell. The crystal structure was solved by X-ray diffraction methods (Ä = 0,087; 3085 observed reflexions). The structure consists of planar and almost square W4N4-eight-membered rings with alternating W-N bond lengths. The distorted octahedral environment of the tungsten atoms is completed by three terminal Cl-ligands and by the oxygen atom of a POCI3 molecule, which is coordinated trans to the W = N triple bond. The two additional POCI3 molecules are weakly linked to two of the four POCI3 solvate molecules, giving rise to an increase of the W 0 bond lengths to these donor groups.