[Ti{η5-1-(SiMe3)-3-(R)-C9H5}Cl2(OEt)] half-sandwich complexes: Synthesis, solid-state structure, hirshfeld surface analysis and theoretical studies.

• Synthesis of titanium indenyls with alkyloxy ligands. • Single-crystal structure analysis confirms a piano-stool arrangement at titanium. • Structural and electronic analysis using DFT calculations provides significant insights into the complexes molecular orbitals and the molecular electrostatic surface potentials. Indenyl-titanium trichloride complexes of type [Ti{η5-1-(SiMe 3)-3-(R)-C 9 H 5 }Cl 3 ] (R = SiMe 3 (3a); R = t Bu (3b)) were obtained by treatment of Li[1-(SiMe 3)-3-(R)-C 9 H 5 ] (R = SiMe 3 (1a); R = t Bu (1b)) with titanium tetrachloride (2) in a 1:1 molar ratio in the presence of isopropanol and SOCl 2. Compounds [Ti{η5-1-(SiMe 3)-3-(R)-C 9 H 5 }Cl 2 (OEt)] (R = SiMe 3 (4a); R = t Bu (4b)) are accessible by reacting 1a,b (R = SiMe 3 (1a); R = t Bu (1b)) with TiCl 4 (2) in the presence of ethanol and SOCl 2 , or when 3a,b were treated with equimolar amounts of EtOH in refluxing benzene. Spectroscopic methods and single crystal X-ray diffraction analysis confirmed the piano-stool geometry of 3a and 4b in the solid state. Hirshfeld surface analysis using 2D fingerprint plots of 3a and 4b were conducted to elaborate non-covalent, intermolecular interactions existing in the solid state, which accounted for the strengthening of the crystal lattice. The molecular structures of the 3 and 4 were further investigated by quantum-chemical calculations. The geometries of the compounds were optimized at the B3LYP/6-31G(d)+LANL2DZ level of theory, and their related molecular parameters including frontier orbital energy gap and molecular electrostatic surface potential have also been calculated to better understand their properties. [Display omitted] [ABSTRACT FROM AUTHOR]