Darstellung, Kristallstruktur und Infrarotspektrum von [MoNCl3 · POCl3]4/Preparation, Crystal Structure and Infrared Spectrum of [MoNCl3 · POCl3]4

Abstract

Abstract [MoNCl3 · POCl3]4 is prepared both by the reaction of MoNCl3 with POCl3 as well as by the reaction of MoCl5 with NCl3 in the presence of POCl3. [MoNCl3 · POCl3]4 crystallizes in the monoclinic space group P21/c with 2 tetrameric molecules in the unit cell. The crystal structure was solved by X-ray diffraction methods (R = 0.033, 1821 observed reflections). The structure consists of planar and almost square Mo4N4-eight-membered rings with alternating Mo-N bond lengths. The distorted octahedral environment of the molybdenum atoms is completed by three terminal Cl-ligands and by the oxygen atom of a POCl3 molecule, which is coordinated trans to the Mo ≡ N triple bond. The IR spectrum is discussed with respect to the vibrational spectra of the isoelectronic niobium complex [NbOCl3 · POCl3]4.