Inhaltsu È bersicht. Bei der Umsetzung von [(Mo 6 I i 8 )I a 6 ] 2± mit (SCN) 2 in Dichlormethan bei ±20 °C entsteht das Hexaisothiocyanato-Clusteranion [(Mo 6 I i 8 )(NCS) a 6 ] 2± . Die Ro È ntgenstrukturanalyse an einem Einkristall von (n-Bu 4 N) 2 [(Mo 6 I i 8 )(NCS) a 6 ] ´2 Me 2 CO (monoklin, Raumgruppe P2 1 /c, a = 13,168(5), b = 11,964(5), c = 24,636(5) A Ê , b = 104,960(5)°, Z = 2) zeigt, daû ausschlieûlich u È ber die Stickstoffatome gebundene Rhodanidgruppen mit Mo±N-Absta È nden von 2,141±2,150 A Ê , Mo±N±C-Winkeln von 166± 178°und N±C±S-Winkeln von 174±180°vorliegen. In den Schwingungsspektren beobachtet man die fu È r N-gebundenes Rhodanid charakteristischen Innerligandschwingungen in den Bereichen 2073±2054 (m CN ), 846±844 (m CS ) und 480± 462 cm ±1 (d NCS ). Synthesis, Crystal Structure, and Vibrational Spectra of (n-Bu 4 N) 2 [(Mo 6 I i 8 )(NCS) a 6 ] Abstract. By treatment of [(Mo 6 I i 8 )I a 6 ] 2± with (SCN) 2 in dichloromethane at ±20 °C the hexaisothiocyanato cluster anion [(Mo 6 I i 8 )(NCS) a 6 ] 2± is formed. The X-ray structure determination of (n-Bu 4 N) 2 [(Mo 6 I i 8 )(NCS) a 6 ] ´2 Me 2 CO (monoclinic, space group
P2 1 /c, a = 13.168(5), b = 11.964(5), c = 24.636(5) A Ê , b = 104.960(5)°, Z = 2) shows, that the thiocyanate groups are coordinated exclusively via N atoms with Mo±N bond lengths of 2.141±2.150 A Ê , Mo±N±C angles of 166±178°and N±C±S-angles of 174±180°. The vibrational spectra exhibit characteristic innerligand vibrations at 2073± 2054 (m CN ), 846±844 (m CS ) and 480±462 cm ±1 (d NCS ).