Marina S. Molchanova

Computer-aided search for high-density energetic compounds among hydrogen-free heterocycles

Abstract Our general strategy of a computer-aided search for compounds with the desired physicochemical properties includes three principal stages. The first stage is the selection of possible compositions (molecular formulas) and formulation of structural requirements that may ensure the necessary properties of target compounds. The second stage is computer generation of all molecules that conform to the set of structural constraints formulated at the first stage. The third stage includes the estimation of properties for the resultant compounds and selection of the most promising structures, which may be the targets of a subsequent synthetic search. This strategy was successfully applied to search for high-density energetic compounds among nitrogen-containing hydrogen-free aromatic heterocycles structurally similar to the highly stable energetic compound known as TACOT. A number of hypothetical substances with calculated energy content and density higher than those of TACOT were predicted, and certain qualitative structure–property relationships (which may assist in a further search for compounds with similar properties within other classes) were revealed among them. Some of the predicted compounds may be proposed for synthesis, experimental study and possibly for practical use.

General methodology and computer program for the exhaustive restoring of chemical structures by molecular connectivity indexes. Solution of the inverse problem in QSAR/QSPR

Abstract The first attempt to attack an intriguing inverse problem in QSAR/QSPR is presented. The special technique to the exhaustive targeted search of the structures with a given value of molecular connectivity index is described. The general methodology and the combinatorial algorithm are considered. The selection criteria for the correct generation of graphs and multigraphs with the given distribution of edge types or vertex types are developed. The RING program for the exhaustive generation of structures with the given connectivity index is described, and several examples of its successful application are discussed. A demo version of RING is included in this issue.

Computer generation of chemical structures using the gem program

A new program for generating chemical structures starting from the given molecular formula is described. The generation includes two stages. The first step is exhaustive combinatorial enumeration of molecular graphs with the given gross formula by the GEM structural generator. At the second step, these molecular graphs in the form of connectivity matrices are converted to 3D models by the MOLGEO program. The possible applications of this software are discussed.