Ti(η5-1-SiMe3-C9H6)(Cl)2(OR): Structure and bonding

Treatment of Ti(eta(5)-1-SiMe3C9H6)Cl-3 (1) with LiOR (2a, R = 2,6-tBu2C6H3; 2b, R = 2,6-Ph2C6H3; 2c, R = (C3H7)-C-i; 2d, R= (C4H9)-C-t ) in a 1:1 M ratio produced half-sandwich compounds Ti(eta(5)-1-SiMe3C9H6)Cl-2 (OR) (3a, R = 2,6-(Bu2C6H3)-Bu-t; 3b, R = 2,6-Ph2C6H3; 3c, R = (C3H7)-C-i; 3d, R = (C4H9)-C-t) in high yield. Compounds 3c,d were also accessible, when 1 was reacted with a onefold excess of HOR (2c, R = (C3H7)-C-i; 2d, R = (C4H9)-C-t) in refluxing benzene. The molecular structure of 3b in the solid state was determined by single-crystal X-ray diffraction studies, confirming the piano-stool geometry. Quantum chemical calculations at the B3LYP/6-31g(d)+LANL2DZ level of theory were carried out for 1 and 3a-d in order to better understand and rationalize the nature of bonding and thus demonstrate the effect of different substituents on the structural and electronic properties in these compounds. The studies reveal a high electron density on the Ti(IV) ion for 3c and 3d as compared to 3a and 3b, and also showed the possibility of controlling and fine tuning the electron density on the Ti(IV) ion through the introduction of different alkyloxy or aryloxy substituents. (C) 2018 Elsevier B.V. All rights reserved.