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

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.

Microwave-assisted synthesis and sublimation enthalpies of hemiporphyrazines

It was established that microwave irradiation solvent-free processing of 2,6- diaminopyridine or 1,3-phenylenediamine with phthalonitrile or 4-tert-butylphthalonitrile led to corresponding hemiporphyrazines with sufficiently high yields and a huge reduction in the time required for synthesis, from 8–12 h to 20 min. The data of IR and UV-vis spectroscopies and elemental analysis of the final products were found to be similar to those described in literature. The obtained hemiporphyrazines were characterized by 1H and [Formula: see text]C NMR data. We applied the Knudsen effusion method with mass spectrometric control of vapor composition. The mass spectrometric investigations established that the macrocyclic compounds give a stable stream of particles and their enthalpies of sublimation were estimated by the second law of thermodynamics.

Strategies for the attachment of organic functional groups to silicon surfaces and measurement of vapor pressure of ionic liquids

Surface modifications of silicon surfaces have been studied for several decades. There are several approaches for attaching organic molecules with specific functionalities to these surfaces, utilizing both the selectivity of organic molecules, and the electronic properties of silicon. In this thesis we describe two strategies for attaching a fluorophore to chemically modified Si (100) surfaces as the base of a chemical sensor. The Si surfaces are characterized using X-ray Photoelectron Spectroscopy (XPS) and these results were presented and discussed. Ionic liquids represent a relatively new group of compounds that are thermally stable with very low vapor pressures. These unique properties enable ionic liquids to be used in a variety of applications. As the family of ionic liquids keeps growing, there is a need for vapor pressure and thermodynamic data for the vast majority of ionic liquids. In this thesis, the Knudsen effusion method is used to determine the vapor pressure of several ionic liquids in the temperature range of 380 to 420K. The relationship between the structure of ionic liquids and vapor pressure was discussed based on the vapor pressure data. "