Synthesis, structure, spectral properties and theoretical studies of two half-sandwich titanium-complexes with adamantoxy ligands

0474121 - ÚFCH JH 2018 RIV NL eng J - Článek v odborném periodiku
Varga, Vojtěch - Mach, Karel - Pinkas, Jiří - Kubišta, Jiří - Szarka, K. - Gyepes, R.
Synthesis, structure, spectral properties and theoretical studies of two half-sandwich titanium-complexes with adamantoxy ligands.
Journal of Molecular Structure. Roč. 1142, AUG 2017 (2017), s. 248-254. ISSN 0022-2860. E-ISSN 1872-8014
Grant CEP: GA ČR(CZ) GAP207/12/2368; GA ČR(CZ) GA14-08531S
Institucionální podpora: RVO:61388955
Klíčová slova: half-sandwich complex * ionic complex * solid-state structure
Obor OECD: Inorganic and nuclear chemistry
Impakt faktor: 2.011, rok: 2017

Two novel half-sandwich Ti complexes, both incorporating two adamantoxy (OAd) ligands coordinated to their central atoms were synthesized. The complexes were characterized by H-1, C-13, F-19 NMR, El-MS and IR spectroscopy and by single-crystal X-ray diffraction. In both complexes, the coordination environment is pseudo-tetrahedral and is assembled of two O-coordinated adamantoxy and one eta(5)-coordinated permethylcyclopentadienyl ligand. The fourth ligand in complex 1 is a methyl group coordinated through a regular sigma-bond, whereas in complex 2 the same.coordination site is occupied by the methyl group of the balancing (C6F5)(3)BMe- anion. DFT computations complemented with NBO analyses of 2 have unveiled, that in addition to the electrostatic interactions occurring between the half-sandwich titanocene moiety and the anionic ligand, delocalization of one methyl C-H bond into the available acceptor orbital on the central atom takes place. AIM analyses of 2 have revealed the presence of a Bond Critical Point between the metal atom and the anionic methyl group. These results prove foundation for the description of 2 as a zwitterionic complex coupled with a concurrent Ti...C-H agostic interaction in its molecule. The comparison of 2 with its analogous complex equipped with two Ot-Bu ligands instead of both OAd has suggested only a minor change in the extent of the agostic interaction, despite significant geometric differences between the two complexes.
Trvalý link: http://hdl.handle.net/11104/0271236