UV absorption spectra of pentachlorophenol and amine hydrogen bonded complexes in the solid state

UV absorption spectra of thin polycrystalline layers of pentachlorophenol adducts with tertiary amines were studied. The position of the long wavelength absorption band and its half width were correlated with ΔρΚa. In the inversion (critical) range where the proton transfer takes place absorption ascribed to both non-proton-transfer (HB) and proton-transfer (PT) states is observed. The results presented in this paper together with those published so far seem to indicate a broad asymmetrical single minimum potential for the proton motion with a shoulder close to the zero vibrational level or a double mimimum with a low barrier

A ring conformation of androstan-3-one

<p>For solid-state structures of androstan-3-one derivatives presented in Cambridge structural database (CSD), the puckering parameters for the six-membered rings were calculated to investigate the ring conformation. It was found that for the A-ring, except for typical chair conformation, the boat conformation appears very often. This conformation is also possible for the rings B and C. There are a few compounds with boat conformation of A- and B- or A- and C-ring, but simultaneous boat conformation of B- and C-ring has not been found. The methyl substituents at 10 and 13 position of the androstane-3-one as well as carbonyl group at the 3-carbon atom play a significant role in the stabilisation of the structure of androstan-3-one.</p> <p></p

Structure and Spectroscopic Behaviour of Adduct of 2,6-dichloro-4-nitrophenol with 2,4,6-trimethylpyridine

2,4,6-trimethylpyridinium 2,6-dichloro-4-nitrophenolate crystallizes in monoclinic system, space group Ρ2$\text{}_{1}$/c, a = 7.534(2), b = 26.673(5), c = 8.452(2) Å, β = 116.16(3)°, Z = 4. The planar molecules are arranged in the lattice as antiparallel oriented pairs with the symmetry centre. The O$\text{}^{-}$···Η-Ν$\text{}^{+}$ hydrogen bonds are relatively long, 2.686(4) Å. The C-O bond length, 1.250(4) A, indicates an extended charge separation. The IR and UV-VIS spectra in KBr pellets confirm the ion pairs to be present in the solid state