MNDO calculations on hydrogen bonding complexes of cyanides and isoeyanides, and of acetylene and diacetylene: Use of modified cote-repulsion potential

Abstract

Some H-bonded complexes are studied with the MNDO/H method, proposed originally by Burstein and Issaev (BI).The advantage of using BI potential is that, with the same general form of the core-potential function one can calculate the H-bonding energy of all pairs X ... H (X=N, O, F, C) by changing only the values of the parameters in different situations. The sets of parameters chosen for carbon are seen to perform well for the isocyanides as well as for the unsaturated π-systems (acetylene and diacetylene), but generality in this aspect needs to be established after further application to various types of compounds. As carbon exhibits different types of bonding in different environments, it is unlikely that the same set of parameters would perform equally well in all situations. A bond order dependent parameter may provide a more general solution to this problem.