RESUMO
The noteworthy structural feature of the title complex, poly[acetonitrile-tetra-µ(2)-thio-cyanato-barium(II)digold(I)], {[Au(2)Ba(SCN)(4)(CH(3)CN)]}(n), is that the bis-(thio-cyanato)-aurate(I) anion adopts both monomeric and trimeric motifs. The trimer unit has an Auâ¯Au distance of 3.1687â (3)â Å. In both the monomeric and trimeric units, the Au(I) atoms are also bonded to two S atoms. Within the trimeric unit, the Au(I) atoms exist in differing environments; one Au atom has a T-shaped three-coordinate geometry while the other has a square-planar four-coordinate geometry. The Au(I) atom of the monomer adopts a linear two-coordinate geometry. The extended structure can be described as a three-dimensional coordination polymer consisting of chains of Ba atoms bridged by thio-cyanate N atoms. These chains are cross-linked via the gold monomeric and trimeric units.
RESUMO
In the title compound, [Au(2)Ba(NCS)(4)(C(20)H(24)O(6))](n), the dithio--cyanato-aurate(I) anion adopts a dimeric structure with an Auâ¯Au distance of 3.1109â (10)â Å; both Au(I) atoms are also bonded to two S atoms. The Ba(II) ion adopts an irregular BaN(3)O(6) geometry, arising from the crown ether and three adjacent thio-cyanate N atoms; the extended structure of the complex can be described as a one-dimensional coordination polymer generated by the Baâ¯N inter-actions (two on the endo side and one on the exo side of the crown ether) running parallel to the b axis, with an anti-parallel arrangement of ribbons in the unit cell.
RESUMO
A series of bis(thiocyanato)gold(I) complexes with Au-Au interactions show luminescence in the range from 500 to 670 nm. The series of salts correlates emission energy with the reciprocal of the Au-Au distance. As the Au-Au distance increases, the emission energy decreases. The ligand system provides no framework for the Au-Au interaction. The emission energy seems totally determined by the Au-Au distance.
RESUMO
A library of tripodal amine ligands with two oxime donor arms and a variable coordinating or noncoordinating third arm has been synthesized, including two chiral ligands based on l-phenylalanine. Their Ni(II) complexes have been synthesized and characterized by X-ray crystallography, UV-vis absorption, circular dichroism, and FTIR spectroscopy, mass spectrometry, and room-temperature magnetic susceptibility. At least one crystal structure is reported for all but one Ni/ligand combination. All show a six-coordinate pseudo-octahedral coordination geometry around the nickel center, with the bis(oxime)amine unit coordinating in a facial mode. Three distinct structure types are observed: (1) for tetradentate ligands, six-coordinate monomers are formed, with anions and/or solvent filling out the coordination sphere; (2) for tridentate ligands, six-coordinate monomers are formed with Ni(II)(NO(3))(2), with one monodentate and one bidentate nitrate filling the remaining coordination positions; (3) for tridentate ligands, six-coordinate, bis(mu-Cl) dimers are formed with Ni(II)Cl(2), with one terminal and two bridging chlorides filling the coordination sphere. The UV-vis absorption spectra of the complexes show that the value of 10 Dq varies according to the nature of the third arm of the ligand. The trend based on the third arm follows the order alkyl/aryl < amide < carboxylate < alcohol < pyridyl < oxime.