A. N. Utenyshev

Structural studies of 1,3-oxazolidine-containing spiropyrans

New 3’-(4-chlorophenyl)-5’,5’-dimethyl-2’-oxospiro[(2H)-chromene-2,4’-1,3-oxazolidine] was synthesized to study the donor influence of the chlorine atom at the N-phenyl substituent on the structure and photochromic properties of 1,3-oxazolidine-containing spiropyrans. Photochemical properties of synthesized 1,3-oxazolidine derivatives were studied at room temperature in toluene. The X-ray diffraction parameters for the new compound were compared with the data obtained earlier for similar spiropyrans.

Synthesis, structure, and properties of a new representative of the family of calix[4]arene-containing [MnII2MnIII2]-clusters

A new representative of calix[4]arene-containing tetranuclear manganese complexes of the [MnII2MnIII2] type was obtained. According to the data of magnetoochemical studies, the complex exhibits properties of molecular magnet at the temperature below 5 K. Parameters of the exchange interaction and the activation energy were determined. The influence of the peripheral environment on the magnetic properties of the tetranuclear manganese framework in the structure of the complex was revealed.

Synthesis and structure of 1-[(3-hydroxybenzo[b]thiophen-2-yl)methylidene]-3-oxo-5-phenyl-1-pyrazolidinium-2-ide

Potentially tautomeric azomethine imine, 1-[(3-hydroxybenzo[b]thiophen-2-yl)methylidene]-3-oxo-5-phenyl-1-pyrazolidinium-2-ide has been prepared. According to X-ray diffraction, 1H, 13C, and 15N NMR and electronic spectroscopy, the compound exists as 3-hydroxybenzothiophene structure containing intermolecular hydrogen bond between the hydroxy group and the carbonyl oxygen of the pyrazolidone ring in crystal state. Quantum chemical calculations predict the possibility of OH and NH tautomeric forms.

MOLECULAR STRUCTURES OF NEW 2-(QUINOLINE-2-YL)-1,3-TROPOLONES

The molecular structures of 5,7-di(tert-butyl)-2-(6,8-dimethyl-4-piperidinoquinoline-2-yl)-3-hydroxytropone and 5,7-di(tert-butyl)-2-(5,8-dimethyl-4-piperidinoquinoline-2-yl)-3-hydroxytropone are determined by the single crystal X-ray diffraction analysis.

Benzenoid-quinoid tautomerism of azomethines and their structural analogs 56. Azomethine imines, derivatives of salicylic and 2-hydroxynaphthoic aldehydes

A study by IR, electronic and NMR (1Н and 13С) spectroscopy together with X-ray structure analysis and quantum chemical calculations using DFT B3LYP/6-31G(d,p) determined N,N´-cyclic azomethine imines — 1-(2-hydroxyphenylmethylidene)-3-oxo-5-phenylpyrazolydin-1-ium-2-yde (1) и 1-[(2-hydroxynaphthalene-1-yl)methylidene]-3-oxo-5-phenylpyrazolydin-1-ium-2-yde (2) — to exist in solutions as isomers with an intramolecular hydrogen bond between the hydroxyl group and the nitrogen of the pyrazolidone ring. Compound 1 undergoes photoexcitation in the wavelength range 363—320 nm followed by luminescence with an anomalous Stokes shift that is caused by the intramolecular excited state proton transfer mechanism (ESIPT effect).

Thiacalix[4]arene-containing M2Ln2 complexes (M = MnII, CoII; Ln = EuIII, PrIII): synthesis, structure, and magnetic properties

Three new representatives of thiacalix[4]arene-containing tetranuclear 3d-4f metal complexes with the M2Ln2 fragment (M = MnII, CoII; Ln = EuIII, PrIII) were synthesized. Their molecular and crystal structures were studied by X-ray diffraction analysis. According to the magnetochemical measurements, the complexes exhibit the paramagnetic properties with weak antiferromagnetic interactions at low temperatures (T < 30–50 K). The influence of the environment of the rare-earth elements on the spin-orbital coupling and magnetic properties of the complexes was found.

Synthesis, structure, and biological activity of the cis-[4-amino-2,2,6,6-tetramethylpiperidine-N,N′]dichloropalladium(ii) complex

A previously unknown palladium complex was synthesized by the reaction of 4-amino-2,2,6,6-tetramethylpiperidine with PdCl2. The X-ray diffraction study showed that the complex formed by 4-amino-2,2,6,6-tetramethylpiperidine with PdCl2 is a chelate, in which the bidentate ligand adopts a boat conformation with the nitrogen atoms occupying cis positions at the palladium atom. The resulting cis-[4-amino-2,2,6,6-tetramethylpiperidine-N,N′]dichloro-palladium(ii) complex exhibits strong antimetastatic activity against experimental B16 melanoma at moderate toxicity.

Synthesis of oxalic acid derivatives and their antitumor activity in experiments in vivo

A series of amino acid derivatives of oxalic acid were obtained. In combination therapy with conventional cytostatics used in lower doses, the new compounds substantially increase the efficacy of the drugs in the treatment of experimental P388 murine leukemia and some its drug-resistant strains.

Specific Features of the Molecular Structure of A New 3-(Benzo[d]Oxazole-2-Yl)- 1-(2-(1,3,3-Trimethylindoline-2-Ylidene) Ethylidene)Naphthalene-2(1H)-One Zinc Chloride Complex

X-ray diffraction is used to determine the structure of a new 3-(benzo[d]oxazole-2-yl)-1-(2-(1,3,3- trimethylindoline-2-ylidene)ethylidene)naphthalene-2(1H)-one zinc chloride complex 1. It is demonstrated that the ligand molecule in complex 1 has a trans–trans–cis conformation in which the indoline nitrogen atom is oriented in the same direction as the chelate ring, which could promote an additional coordination with the complexing atom.

Dependence of Properties and Exchange Coupling Constants on the Charge in the Mn2On and Fe2On Series

The geometrical structure and properties of the neutral and singly charged Mn2O nq and Fe2O nq clusters ( q = 0, ±1) are computed using density functional theory with the generalized gradient approximation in the range 1 ≤ n ≤ 7. The geometrical structures and spin multiplicities of the corresponding species in all six series are similar except for a few exceptions. Antiferromagnetic coupling of total spin magnetic moments of the metal atoms in the lowest total energy states is observed for the majority of species in all six series when n = 1-5; correspondingly, the computed magnetic exchange coupling constants are mostly negative. The states of Mn2O nq and Fe2O nq are nonmagnetic or weakly ferromagnetic when n > 5 except for Mn2O7+ where the ground state is antiferromagnetic. The computed adiabatic electron affinities and ionization energies of the neutral species in both series are quite close to one another and increase as n increases. However, the binding energies of a single oxygen atom and of an O2 dimer decrease as n increases and the Mn2O7+ and Fe2O7+ cations are barely stable with respect to the O2 abstraction. The most stable and least stable species at a given n are the anions and the cations, respectively. The electric dipole polarizability per atom decreases sharply when n moves from 1 to 4 and then remains nearly constant for larger n values in the anion series, whereas it is close to the asymptotic value already at n = 2 in the neutral series.