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Hydroxyderivatives of vitamin D3, including classical 1,25(OH)

The X-ray single crystal investigation revealed that Pd 2+ ion is bonded to tch ligands only via amine nitrogen atoms, forming with two chloride ions a quasi-square metal environment. The crystal slowly looses dmf molecules transforming into complex which can also be obtained by mixing the PdCl 2 and tch water solutions. Both compounds, together with their bromo derivatives, have been intensively investigated by vibrational spectroscopy methods employing the palladium isotope substitution, deuteration and theoretical calculations on the DFT level. All those attempts resulted in complete assignment of the observed bands, in terms of potential energy distribution.

Green crystals of the [Cu(taa)2(dmf)]2 (where taa denotes 2-thiopheneacetate anion) complex crystallize from the dmf solution of another polymeric [Cu2(taa)4]n complex. Obtained compound was investigated by X-ray diffraction methods, which revealed that the complex consists of centrosymmetric dimers where the bidentate 2-thiopheneacetate anions form syn, syn bridges between copper(II) ions. The coordination polyhedron of each metal ion is completed by the dmf molecule. The complex structure is well reflected in the infrared spectrum, where the assignment of the bands originating from the Cu–COO and Cu–dmf vibrations was confirmed with the aid of metal isotope substitution.

The crystal structure of a novel polymeric copper(II) complex with 2-thiopheneacetic acid is presented and the vibrational spectra are discussed. The copper(II) atoms and coordinating carboxylate oxygen atoms form the [Cu2O8] dinuclear units typical for other carboxylates of this metal. The units are directly linked via two, relatively short Cu–O interactions and form polymeric chains along the b axis. A structural two- and threefold disorder has been found for the thiophene rings. The IR and Raman spectra of the title complex and free ligand are interpreted with help from literature data and deuteration effects. The absorption bands that are related to Cu–Cu core vibrations have been localized by a 63Cu–65Cu labelling technique.

Vibrational spectra of tetrakis(acetato)diaquadicopper(II) complex have been deeply examined in order to provide a detailed description of dynamics of [Cu 2 O 8 C 4 ] core being a typical structural unit of most copper(II) carboxylates. Low frequency bands related to significant motions of metal atoms were detected by metal isotope substitution. Observed spectra and isotope shifts were reproduced in DFT calculations. For clear presentation of computed normal vibrations, a D 4h symmetry approximation was successfully applied. Basing on observed isotope shifts and calculation results, all skeletal vibrations have been analyzed including normal mode with the largest Cu ⋯ Cu stretching amplitude assigned to Raman band at 178 cm −1 .