Molecular Structure, Thermodynamic and Spectral Characteristics of Metal-Free and Nickel Complex of Tetrakis(1,2,5-thiadiazolo)porphyrazine

Abstract

The Knudsen effusion method with mass spectrometric control of the vapor composition was used to study the possibility of a congruent transition to the gas phase and to estimate the enthalpy of sublimation of metal-free tetrakis(1,2,5-thiadiazolo)porphyrazine and its nickel complex (H2TTDPz and NiTTDPz, respectively). The geometrical and electronic structure of H2TTDPz and NiTTDPz in ground and low-lying excited electronic states were determined by DFT calculations. The electronic structure of NiTTDPz was studied by the complete active space (CASSCF) method, following accounting dynamic correlation by multiconfigurational quasi-degenerate second-order perturbation theory (MCQDPT2). A geometrical structure of D2h and D4h symmetry was obtained for H2TTDPz and NiTTDPz, respectively. According to data obtained by the MCQDPT2 method, the nickel complex possesses the ground state 1A1g, and the wave function of the ground state has the form of a single determinant. Electronic absorption and vibrational (IR and resonance Raman) spectra of H2TTDPz and NiTTDPz were studied experimentally and simulated theoretically.

Molecular and Electronic Structures of Macrocyclic Compounds Formed at Template Synthesis in the M(II)—Thiocarbohydrazide—Diacetyl Triple Systems: A Quantum-Chemical Analysis by DFT Methods

“…Interest in metal macrocyclic compounds and prediction of their physicochemical characteristics (including the calculation of molecular and electronic structures using quantum-chemical calculations of various levels) continues to be consistently high on the part of researchers, as evidenced by a number of recent works, in particular, [27][28][29][30][31][32][33][34][35][36][37][38][39][40], and this article is just one of many devoted to the above topics. In summary, we would like to emphasize that the above-mentioned data of quantum-chemical calculations performed using three different variants of density functional theory, namely, B3PW91/TZVP, M06/TZVP, and OPBE/TZVP chemistry models, unambiguously predict the possibility of the existence of macrocyclic metal complexes Ni(II), Cu(II), and Zn(II) with macrocyclic tetradentate ligand, double-deprotonated form 3,10-dithio-6,7,13,14-tetramethyl-1,2,4,5,8,9,11,12-octaazacyclotetradecatetraene-1,5,7,12 (L 2− ) with the ratio M(II): L 2− = 1:1, resulting from template synthesis in the ternary systems M(II)-thiocarbohydrazide-diacetyl (M = Ni, Cu, Zn).…”

Vaporization Processes and Accurate Molecular Structure of a Number of Organic and Inorganic Compounds Promising for Use in Technologies Involving the Gas Phase

“…Строение и энергетика металлокомплексов порфиразина, их аннелированных и замещенных производных В цикле статей [29][30][31][32][33][34][35][36] рассмотрено влияние природы металла и периферийных заместителей на структуру и спектральные свойства комплексов порфиразинов с переходными металлами и представителями лантанидов.…”

“…Масс-спектрометрические исследования процессов сублимации соединений тетратиадиазолопорфиразина H2TTDPz и тетратиадиазолопорфиразината никеля NiTTDPz показывают, что NiTTDPz образует устойчивые потоки частиц в интервале температур T = 632-717 К, а сублимация H2TTDPz сопровождается частичным разложением [34].…”

“…Влияние природы металла (Ca, Ni или Zn) и лиганда (порфиразин или тиадиазол-аннелированный порфиразин) на геометрическое, электронное строение и электронные спектры поглощения комплексов MPz и MTTDPz (M = Ca, Ni, Zn) изучено с использованием расчетов методами DFT и TDDFT на уровне B3LYP/pcseg-2 [31,34]. На основании результатов анализа распределения электронной плотности методами NBO и QTAIM обнаружено существенное различие в природе химических связей Ca-Np и Zn-Np: при переходе от Ca(d 0 ) к Zn(d 10 ) наблюдается существенное уменьшение вклада ионной составляющей и увеличение вклада ковалентной.…”

Molecular Structure of Nickel Octamethylporphyrin—Rare Experimental Evidence of a Ruffling Effect in Gas Phase

“…As many transition metal species are of a multireference character, the applicability of a single determinant DFT approach is questioned for porphyrin metal complexes. Nevertheless, our recent study [ 16 ] concludes that the ground state of nickel(II) complex with tetrakis(1,2,5-thiadiazolo)porphyrazine is clearly single-reference. This suggests that the DFT approach is most likely valid for other nickel(II) macroheterocycles.…”