Quantum chemical studies of propene, ethylene, acetylene and dihydrogen reactivity in the insertion reaction into the titanium‐alkyl bond

Abstract

SUMMARYUsing the ab initio method of SCF MO LCAO") in a valency-splitted basis of the Gaussian functions we have studied the addition of various monomers (C3H8, C2H4, C2H2) and dihydrogen to the titanium-alkyl bond in the complex H2TiCH,. The structure of transition states in the insertion reaction, heats of x-complex formation and activation energies for the insertion of the coordinated monomers have been calculated. The calculation results show that the reactivity decreases in the order C2H2 > C2H, > C3HB > Hi?. According to the results obtained, the energy of the n*-antibonding orbital of monomers can serve as an index of relative reactivity in the insertion reaction into the metal-alkyl bond.

Models of macromolecular chains based on Classical and Quantum Mechanics: comparison with Gaussian models

“…On the other hand, Eqs. (28) and (38) differ clearly from one another. This gave rise to a paradox (even before making any attempt to include quantum effects and the uncertainty principle!…”

“…However, it does not seem that Eqs. (38) and (39) imply the Gaussian distribution for the individual bond lengths (that is, Eq. (10)).…”

“…[13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] as samples of recent studies, not based upon Quantum Mechanics and to ref. [30][31][32][33][34][35][36][37][38][39][40] as examples of quantum mechanical ones. For a full variety of cases in Polymer Science, it may be not easy or, even, extremely difficult, to set up quantum-mechanical formulations: then, the probabilistic or Classical Mechanics approaches may well be the only available tools, in practice.…”

Hindered macromolecular chains: A quantum mechanical model

“…The proof of Eqs. (30), (31), (32), (33) and (34) will be reported, in outline, in Appendix 2. For definiteness, we shall give below the explicit expression for T,, for N = 3:…”

“…(43), (31),(32),(33), and(34) can be compared to the alternative quantum partition function, Z, , obtained issue of rotational invariance with another multiplicative potential V,,o, which, essentially, has the same properties and order of magnitude as V,. That is, V,,o does not contain any differential operator with respect to any angle, but it contains all terms of orderh z M .…”