RESUMO
Internal dynamics of 17- and 21-substituted progesterone derivatives was studied by the methods NMR, inelastic incoherent neutron scattering (IINS) and quantum chemical calculations. Comparison of the computer simulation of the phonon density of states (PDS) spectrum performed by the density functional theory (DFT) method with the spectrum obtained after a transformation of the experimental results permits an interpretation of subsequent modes. Only for 17OH prg the second moment of NMR line decreases to 10 G2 near room temperature, most probably because of the oscillations about direction of inter-molecular hydrogen bond. Significant mobility of protons in this compound is also confirmed by a low intensity of the elastic peak in INS and broadening of this spectrum.
Assuntos
Transferência de Energia , Espectroscopia de Ressonância Magnética/métodos , Modelos Moleculares , Difração de Nêutrons/métodos , Progesterona/análogos & derivados , Progesterona/química , Simulação por Computador , Elasticidade , Hidróxidos/química , Conformação Molecular , Prótons , Pontos Quânticos , TemperaturaRESUMO
The molecular structure of free radicals formed in gamma-irradiated orthorhombic single crystals of hydrated testosterone was investigated by Electron Nuclear Double Resonance (ENDOR) spectroscopy. Only one kind of radical was observed, which is formed by addition of hydrogen atom to oxygen atom O(3). We observed interaction of the unpaired electron, which is delocalized on the carbons C(3), C(4) and C(5), with one alpha-proton in position 4 and with four unequivalent beta-protons connected with the carbon atoms C(2) and C(6). The matrices of the hyperfine couplings and the g-factor of the radical are given.
Assuntos
Testosterona/química , Testosterona/efeitos da radiação , Cristalização , Espectroscopia de Ressonância de Spin Eletrônica/métodos , Raios gamaRESUMO
The molecular structure of free radicals formed in certain gamma-irradiated steroid hormones and cholesterol determined by electron spin resonance (ESR) and electron nuclear double resonance studies has been reviewed. The influence of intermolecular interactions and hydrogen bonds on the structure of the radicals formed, as well as the effect of substitution of hydroxyl group on the alpha-hyperfine splitting tensor have also been analyzed.
Assuntos
Espectroscopia de Ressonância de Spin Eletrônica/métodos , Esteroides/química , Esteroides/efeitos da radiação , Colesterol/química , Colesterol/efeitos da radiação , Cristalização , Radicais Livres/análise , Radicais Livres/efeitos da radiação , Raios gama , Ligação de Hidrogênio , Estrutura MolecularRESUMO
The molecular structure of free radicals formed in gamma-irradiated monoclinic and orthorhombic single crystals of hydrated testosterone were investigated by EPR spectroscopy. Two different types of radical were observed. In the monoclinic form, the radical arises by the loss of a hydrogen atom from the carbon atom C(2), whereas, in the orthorhombic form, it arises by addition of a hydrogen atom to the oxygen atom O(3). The hyperfine spectrum of the radical formed in the monoclinic single crystal originates from the interaction of the unpaired electron with one alpha-proton in position 2 and two non equivalent beta-protons in position 1. In the orthorhombic single crystal, we observed interaction of the unpaired electron, which is delocalized on the carbons C(3), C(4) and C(5) with one alpha-proton in position 4 and with four nonequivalent beta-protons connected with the carbon atoms C(2) and C(6). The hyperfine tensors of the coupling and the g-tensor of the radicals are given.
