Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalyse

The crystal structures of ds-(«-Bu4N)2[ReBr4(NCS)2] (1) (triclinic, space group Pi, a = 11.475(6), b = 20.096(16), c = 22.144(11) A, a = 110.56(6), ß = 92.97(5), 7 = 99.77(7)°, Z = 4), m-(n-Bu4NMReBr4(NCSe)i] (2) (triclinic, space group PI, a = 11.527(3), b = 20.237(7), c = 22.07(2) Ä, a = 110.05(4), ß = 93.86(6), 7 = 99.49(4)°, Z = 4) and cis-{nBu4N)2[ReBr4(NCS)(NCSe)] (3) (triclinic, space group PI, a = 11.488(2), b = 20.164(6), c = 22.158(5) A, a = 110.44(2), ß = 93.34(2), 7 = 99.626(18)°. Z = 4) have been determined by single crystal X-ray diffraction analysis. Based on these molecular parameters the low tem­ perature (10 K) IR and Raman spectra of the (n-Bu4N) salts have been assigned by normal coordinate analysis. The valence force constants are fd(ReN) = 1.70 (1), 1.70 (2) and 1.72 (3), fd(ReBr) = 1.36 (1), 1.30 (2) and 1.36 mdyn/Ä (3).