[Mo₆Cl₈]X^a(2−)‐Komplexe mit Pseudohalogeniden in X^a‐Position

Abstract

Komplexe vom Typ A2[Mo6Cl8i]X6a · aq und A′2[Mo6Cl8i]X6a wurden hergestellt (A = NH4+, K+ und A2 = CsH3O++; A′ = (C6H5)4As+, (n‐Bu)4N+, (CH3)4N+; X = (NCO)−, (NCS)−, (NCSe)− und N3−). Die Verbindungen wurden analytisch und röntgenographisch, sowie IR‐, 14N‐NMR‐ und UV‐spektroskopisch charakterisiert. Cyanat ist über Sauerstoff an Molybdän gebunden, während Selenocyanat über Stickstoff an Molybdän koordiniert ist. Bei Xa = (NCS)− wurde sowohl N‐ als auch S‐Koordination beobachtet. Partielle Xa‐Besetzung liegt in der Verbindung‐[(CH3)4N]2[Mo6Cl8]Cl3(NCS)3 vor. Im UV konnten MoXi‐ und MoXa‐Charge‐Transfer‐Wechselwirkungen gesondert beobachtet werden.

Synthesis, Characterization, and Substitution Chemistry of [Bu4N]2[W6Cl8(OSO2CF3)6]. A Versatile Precursor for Axially Substituted Clusters Containing the {W6Cl8}4+ Core

“…The triphenylphosphine oxide complex 8 has a ν(PO) stretching band at 1063 cm -1 , which is shifted to lower energy relative to the ν(PO) band at 1189 cm -1 of free triphenylphosphine oxide. The ν(CN) band of the thiocyanate cluster 5 is lowered in energy relative to free thiocyanate, from 2053 cm -1 in KSCN to 2047 cm -1 in 5 , which can be attributed to N-bonding of the ligand to tungsten . The ν(CN) band in 6 is also shifts from 2072 cm -1 in KNCSe to 2042 cm -1 in 6 , indicating that the selenocyanate ligand is also bound to tungsten through the nitrogen atom.…”

“…The ν(CN) band of the thiocyanate cluster 5 is lowered in energy relative to free thiocyanate, from 2053 cm -1 in KSCN to 2047 cm -1 in 5, which can be attributed to N-bonding of the ligand to tungsten. 49 The ν(CN) band in 6 is also shifts from 2072 cm -1 in KNCSe to 2042 cm -1 in 6, indicating that the selenocyanate ligand is also bound to tungsten through the nitrogen atom. The cyanate cluster 7 exhibits an increase in the energy of the ν(CN) band, from 2162 cm -1 in NaNCO to 2217 cm -1 in the cluster, which is indicative of N-bonding, as observed in a variety of other cyanate complexes.…”

Substitution and Redox Chemistry of [Bu4N]2[Ta6Cl12(OSO2CF3)6]

“…This 14 cm -1 frequency shift to higher energy contrast with the observations for [Mo 6 Cl 8 (NCS) 6 ] 2- where the two ν(CN) bands shift by 13 and 35 cm -1 to lower energy. The NCS - ligands of [Mo 6 Cl 8 (NCS) 6 ] 2- are also nitrogen bound as determined by IR, 15 N NMR, and X-ray crystallography . The average M−N−C angle for the molybdenum cluster is 171° versus 162° for the tantalum cluster.…”