Normal coordinate analysis of titanium(IV) halide: monoethylenediamine complexes

Abstract

A partial normal coordinate analysis was performed for the Ti(en)X, complexes, assuming gnlrclze configuration of the ligand and o\.erall symmetry of C, for the complex. Comparison of the calculated frequencies with the available experimental data supports the assumption of the chelate struct~ire for the conlplexes and also confir~sls the previous assignnients for the Ti-N stretching frequencies. Some new assignments are proposed in the 900-300 cm-' region.Canadian Journal of Chemistry, 47, 167 (1969) IntroductionThe preparation and infrared spectra of the compounds Ti(en)C1, and Ti(en)Br, have bee11 reported recently (1). The spectra were found to be qualitatively consistent with a chelate structure with the ethylenediamine in the ga~tche configuration. Assignments were made for both metal-nitrogen and metal-halide vibrational modes in the complex.In this paper we report the results of a vibrational analysis based on the proposed chelate structure for the Ti(en)Cl, and Ti(en)Br, molecules.Results The skeleton of the proposed structure is shown in Fig. 1. In the model the ethyle~ledia-mine ligand has been coordinated in the cis configuration. This increased the symmetry of the complex from C, to C,,. All the initial calculations were done for a molecule of this symmetry. However, in order to clarify certain assignments the final calculations were done for the ligand in the gauche configuration and hence