The Influence of the Solvation on the Bonding of Molecular Complexes of Diatomic Halogens With Nitrogen-Containing Donors and Their Stability With Respect to the Heterolytic Halogen-Halogen Bond Splitting.

In the framework of SMD approach a systematic computational study of structural, electronic and thermodynamic properties of molecular complexes of Cl, ICl and I with series of N-containing Lewis bases in solvents of different polarity was carried out. Results indicate that molecular complexes of Cl with strong and medium-strong LB undergo spontaneous ionization in the acetonitrile solution. The increase of the solvent polarity can change the nature of interaction in X'XLB systems from molecular X'X ← LB donor-acceptor complexes to 3-center 4-electron bound X'→X ← LB in solvents of medium polarity and to the contact ion pairs X'→[XLB] in polar solvents.

Facile heterolytic bond splitting of molecular chlorine upon reactions with Lewis bases: Comparison with ICl and I.

Formation of molecular complexes and subsequent heterolytic halogen-halogen bond splitting upon reactions of molecular Cl with nitrogen-containing Lewis bases (LB) are computationally studied at M06-2X/def2-TZVPD and for selected compounds at CCSD(T)/aug-cc-pvtz//CCSD/aug-cc-pvtz levels of theory. Obtained results are compared with data for ICl and I molecules. Reaction pathways indicate, that in case of Cl∙LB complexes the activation energies for the heterolytic Cl-Cl bond splitting are lower than the activation energies of the homolytic splitting of Cl molecule into chlorine radicals.

Structures and stability of I and ICl complexes with pyridine: Ab initio and DFT study.

Theoretical investigation of thermodynamic stability and bonding features of possible isomers of the molecular and ionic complexes of pyridine with molecular iodine and iodine monochloride IX (X = I,Cl) is presented. M06-2X DFT functional is found to provide bond distances and dissociation energies which are close to those obtained at high-level ab initio CCSD(T)/aug-cc-pvtz//CCSD/aug-cc-pvtz benchmark computations for the most stable isomers, formed via donation of a lone pair of nitrogen atom of pyridine to the iodine atom. These isomers are by 23-33 kJ mol (in case of I) and by 39-56 kJ mol (in case of ICl) more stable than other molecular complexes.

Hydrogen Activation by Frustrated and Not So Frustrated Lewis Pairs Based on Pyramidal Lewis Acid 9-Boratriptycene: A Computational Study.

Structural features and reactivity of frustrated Lewis pairs (FLPs) formed by pyramidal group 13 Lewis acids based on 9-bora and 9-alatriptycene and bulky phosphines P Bu, PPh, and PCy are considered at the M06-2X/def2-TZVP level of theory. Classic FLP is formed only in the B(CMe)CH/P Bu system, while both FLP and donor-acceptor (DA) complex are observed in the B(CF)CF/P Bu system. Formation of DA complexes was observed in other systems; the B(CH)CH·P Bu complex features an elongated DA bond and can be considered a "latent" FLP.

Lewis acid stabilized group 13-15 element analogs of ethylene.

Stabilization of hydrogen-substituted group 13-15 compounds H EE'H (E = B, Al, Ga; E' = P, As, Sb) by Lewis acids is considered at B3LYP/def2-TZVP, B3LYP-D3/def2-TZVP and M06-2X/def2-TZVP levels of theory. It is shown, that for many Lewis acids additional reactivity beyond the DA complex formation with H EE'H monomer is expected. In case of complexation with E(C F ) , F/H exchange reactions with group 13 bound hydrides are predicted to be exothermic and accompanied by the activation energies which are smaller than dissociation of the complex into components.