Conformational isomerism of the seven-membered heterocycle in a single crystal of [η2-Ph2P(O)(CH2)2C(O)NМе2]TiF4 adduct

• Published in: Doklady. Chemistry 2016-09, Vol.470 (1), p.255-259
• Main Authors: Il’in, E. G., Parshakov, A. S., Aleksandrov, G. G., Yarzhemskii, V. G., Danilov, V. V., Bodrin, G. V., Goryunov, E. I., Nifantev, E. E.
• Format: Article
• Language: English
• Subjects: Atomic structure; Chelates; Chemical bonds; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Crystal structure; Crystallography; Geometry; Industrial Chemistry/Chemical Engineering; Molecular structure; Quantum chemistry; Single crystals
• ISSN: 0012-5008; 1608-3113
• DOI: 10.1134/S0012500816090068

The crystal structure of TiF 4 [(Ph 2 P(O)CH 2 CH 2 C(O)NMe 2 )] chelate ( I ) was studied by X-ray crystallography, which revealed four crystallographically independent complex molecules of similar structure ( 1 – 4 ). It was found that the molecules are only slightly different in the bond lengths between the coordinated atoms and the central titanium ion and considerably different in the geometry of the seven-membered TiOPCCCO chelate ring. The geometry of the chelate rings was found to be almost identical in each pair of complexes 1 , 2 ( A ) and 3 , 4 ( B ), and a conclusion was drawn on the presence of two conformational isomers ( A and B ) of the chelate complex. Quantum chemical calculations of the relative thermodynamic stability of molecules 1 – 4 were performed, and their geometry optimization led to one theoretical structure. The comparison of the chelate ring geometry in the theoretical structure and in conformers A and B revealed that the conformation of the theoretical chelate ring coincides with that of conformer A .