The effect of immediate environment on bond strength of different bond types-A valence bond study.

The ability to design catalysis largely depends on our understanding of the electrostatic effect of the surrounding on the bonds participating in the reaction. Here, we used a simplistic model of point charges (PCs) to determine a set of rules guiding how to construct PC-bond arrangement that can strengthen or weaken different chemical bonds. Using valence bond theory to calculate the in situ bond energies, we show that the effect of the PC mainly depends on the bond's dipole moment irrespective of its type (being covalent or charge shift).

Hydrolytically Stable and Cytotoxic [ONO]Ti(IV)-Type Octahedral Complexes.

A new family of titanium(IV) complexes based on [ONON] diaminobis(phenolato) ligands with Me, Br, Cl, and F ortho substitutions was synthesized and characterized. X-ray structures of three derivatives revealed homoleptic LTi-type compounds that exhibit an octahedral geometry without binding of the dangling amine unit. DFT calculations demonstrated that the preference of an LTi complex is not driven by solvent or ligand substitutions but rather by entropic effects.