Three different theoretical approaches were used for the study of the geometry changes of some coordinated organic ligands. It was shown that the quantum-chemical calculations with variation of the interatomic distances of these ligands may serve as a good approximation for the adequate description of the pseudo Jahn-Teller's effect (PJTE) in them. The theoretical results of these calculations and the one parametric theory of the vibronic activation are in a good agreement with the known experimental data. The ability to describe the geometry changes, caused by coordination, opens a new way for the explanation of the selectivity of catalytic action. The last problem is very important for various needs of homogeneous catalysis.