Structural Particularities of Monodeprotonated Hemihexaphyrazine Complexes with Y, La, and Lu according to Quantum Chemical Calculations

• Published in: Russian journal of inorganic chemistry Vol. 67; no. 3; pp. 350 - 361
• Main Authors: Zhabanov, Yu. A., Giricheva, N. I., Islyaikin, M. K.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.03.2022; Springer Nature B.V
• Subjects: Absorption spectra; Chemistry; Chemistry and Materials Science; Coordination compounds; Density distribution; Electronic structure; Hydrogen atoms; Inorganic Chemistry; Ligands; Mathematical analysis; Molecular structure; Nitrogen atoms; Oxidation; Planar structures; Quantum chemistry; Theoretical Inorganic Chemistry; Thiadiazoles; macroheterocycles; molecular structure; porphyrinoids; coordination bond; DFT calculations
• ISSN: 0036-0236; 1531-8613
• DOI: 10.1134/S0036023622030172

The molecular structure of mononuclear noncentrosymmetric complexes of Y, La, and Lu with the ABABAB-type six-membered porphyrinoid hemihexaphyrazine H 3 Hhp of the composition MH 2 Hhp was studied using the DFT method. It was determined that the macrocyclic ligand of these complexes has a planar structure. The electronic density distribution in the MH 2 Hhp molecules was studied by QTAIM calculations and NBO analysis. It was shown that, in each complex, three coordination bonds are formed among the M atom and the nitrogen atom of the pyrrole fragment and two nitrogen atoms of the neighboring thiadiazole fragments. The H 2 Hhp ligand is quasi-tridentate, although the complexes MH 2 Hhp are formed by the substitution of only one hydrogen atom. It was demonstrated that the electronic structure of the complexes MH 2 Hhp is inconsistent with the conventional concepts of the oxidation states of the metal and the ligand in such structures (M I+ H 2 Hhp I– ). Calculations by the TDDFT method determined that the electronic absorption spectra of the complexes MH 2 Hhp contain absorption bands in the IR region, and that the complexes can have pronounced donor properties.