Molecular and crystal structures of dibenzenehemiporphyrazine complexes with dimethylformamide

The crystal structures of the 1 : 1 and 1 : 2 complexes between dibenzenehe miporphyrazine (I) and dimethylformamide (compounds II and III, respectivel y) are determined by X-ray diffraction. In both compounds, the macrocycle h as a saddlelike shape. In III, the conformation of the macrocycle approxima tes the C-2v symmetry, which agrees closely with the results of quantum-che mical calculations for isolated molecule I and complex II. The ring conform ation in crystal II is distorted under the effect of intermolecular interac tions, as is evidenced by short intermolecular contacts. The complexes are stabilized by intermolecular N-H...O and C-H...O hydrogen bends between the hydrogen atoms situated inside the cavity of the macrocycle and the oxygen atoms of the dimethylformamide molecules. (C) 2001 MAIK "Nauka/lnterperiod ica".