PREPARATION, CRYSTAL-STRUCTURE, AND NORMA L-COORDINATE ANALYSIS OF LINKAGE ISOMERIC PENTACHLORORHODANORHENATES(IV)

By treatment of [ReCl5I](2-) with (SCN)(2) in dichloromethane the link age isomers [ReCl5(NCS)](2-) and [ReCl5(SCN)](2-) are formed which hav e been separated by ion exchange chromatography on diethylaminoethyl c ellulose. The X-ray structure determination on single crystals of (n-B u(4)N)(2)[ReCl5(NCS)] (monoclinic, space group P2(1)/n, a = 10.728(5), b = 11.572(5), c = 35.414(5), beta = 91.896(5)degrees, Z = 4) and (n- Bu(4)N)(2)[ReCl5(SCN)] (monoclinic, space group P2(1)/c, a = 15.447(5) , b = 31.140(5), c = 19.459(5), beta = 109.660(5)degrees, Z = 8) revea ls that the thiocyanate group is bonded with the Re-N-C angle of 170.6 degrees or Re-S-C angles of 104.4 degrees and 106.3 degrees. The IR a nd Raman spectra of both linkage isomers are assigned by normal coordi nate analysis using the molecular parameters of the X-ray determinatio n. The valence force constants are f(d)(ReN) = 1.72 and f(d)(ReS) = 1. 30 mdyn/Angstrom.