3. V. N. Eremenko, T. Ya. Velikanova, L. V. Artyukh, and S. V. ~ Shabanova, Izv. Akad. Nauk SSSR, Inorg. Mater., 10, No. 7, 1249-1254 (1974). 4. V. N. Eremenko, T. Ya. Velikanova, and S. V. Shabanova, Refractory Carbides and Their Alloys [in Russian], Naukova Dumka, Kiev (1973), pp. 84-89. 5. A. L. Ivanovskii, V. I. Anisimov, and V. A. Gubanov, Metallofizika (Akad. Nauk Ukr. SSR, Otd. Fiz.), 9, No. 3, 83-87 (1987). 6. A. Oswald, R. Zeller, and P. H. Dederichs, Ber. Kernforschungsanlage Juelich, 2015 (1985). 7. V. P. Zhukov and V. A. Gubanov, Solid State Commun., 56, No. i, 51-58 (1985). 8. V. A. Gubanov, ~. Z. Kurmaev, and A. L. Ivanovskii, Quantum Chemistry of Solid Bodies [in Russian], Nauka, Moscow (1984). 9. V. A. Gubanov, V. P. Zhukov, and A. L. Ivanovskii, Zh. Strukt. Khim., 27, No. 6, 139- 147 (1986). i0. P. Marksteiner, P. Weinberger, A. Neckel, et al., Phys. Rev. B, 33, No. 2, pp. 812-821, No. 10, pp. 6709-6718 (1986). QUANTUM-CHEMICAL ANALYSIS OF ACID-BASE PROPERTIES OF METAL COMPLEXES OF AZAPORPHYRINS BY THE INDO METHOD K. A. Kon'kov, G. M. Zhidomirov, O, L. Kaliya, V. I. Khleskov, and Yu. V. Ivanov UDC 539.194;535.34 Calculations of monoprotonated forms of complexes of tetraazaporphyrin with Cu, Ni, Co, Fe were carried out by the LCAO MO method in an INDO valence approximation. The possible positions of the proton with respect to the com- plex were analyzed. Good agreement was obtained between the theoretical and experimental values of the energies of the long-wave electronic transitions. An explanation has been proposed for the dependence of the basicity of the complex on the nature of the complex forming metal. In addition to their common application as pigments and dyes, azaporphyrins (AP), and particularly, tetraazaporphyrins (TAP), phthalocyanins (Pc) and their substituted derivatives and structural analogs are widely used as catalysts of chemical and electrochemical processes, materials for quantum electronics and electrophotography, active media for transformation of solar energy, as well as many other current technological fields. It should be noted, how- ever, that the degree of knowledge of the electronic structure of AP, the forms of its exis- tence in solutions, and mutual transformations of their forms gravely lags behind the practical problems encountered. One of the most important aspects in AP chemistry is their acid-base properties, since strong acids are often important components on the compositions in technical applications of AP. However, in the treatment of the manifestation of these properties, there are contra- dictory points of view that requiretheoretical approbation. According to one hypothesis (the postulates of which are most fully covered in [i]), the metallocomplexes of AP are weak organic bases and are once protonated even in concentrated solutions of strong acids at one of the nitrogen meso-atoms. The long-way e Q-band in the absorption spectrum of sulfuric acid solutions of AP, resembling in form a similar band in organic solvents, but shifted by more than i00 nm with respect to it, is in particular ascribed to this monoprotonated form. The authors of this hypothesis recently modified it by taking the position that the remaining meso-atoms of nitrogen are bound in this form with the acid molecules by stable hydrogen bonds [2]. Scientific Research Institute of Organic Intermediates and Dyes. Translated from Zhurnal Strukturnoi Khimii, Vol. 30, No. 2, pp. 25-80, March-April, 1989. Original article submitted June i, 1987. 0022-4766/89/3002-0189512.50 ?9 1989 Plenum Publishing Corporation 189
