| Abstract: | Preparation and characterization of bondisomeric bromorhodanorhenates(IV) The new compounds ReBr5(SCN)]2?, ReBr5(NCS)]2?, cis/tr.-ReBr4(NCS)(SCN)]2?, cis-ReBr4(NCS)2]2?, mer-ReBr3(NCS)3]2? are prepared from ReBr6]2? by ligand exchange with NaSCN, KSCN, or (SCN)2 in organic solvents and isolated by ion exchange chromatography on DEAE cellulose. The bondisomers are significantly distinguished by the frequencies of inner ligand vibrations: vCN(S) > vCN(N), vCS(N) > vCS(S), δNCS δSCN. The electronic absorption spectra measured at 10 K exhibit in the region 5700 to 15300 cm?1 all intraconfigurational transitions (t2g3) splitted into 8 Kramers doublets by lowered symmetry (C4v, C2v, Cs) and spin orbit coupling. The O–O-transitions are deduced form vibrational fine structure and confirmed by electronic Raman bands in some cases. The magnetic moments are in the range of 3.0 to 3.9 B.M. |
