A Hexanuclear Niobium Cluster Compound With Intra‐Cluster Chelate Ligands: [Nb₆(OC₂H₄NH₂)₁₂]I₃

Abstract

From the reaction of [Nb6I11] with 2‐aminoethanol in pyridine the cluster compound [Nb6(OC2H4NH2)12]I3 has been obtained and the single‐crystal X‐ray structure determined. It represents the first example of a group VB metal cluster compound with hexanuclear, octahedral metal atom core, which carries intra‐cluster chelate ligands. With the formation of this unprecedented cluster cation we report for the first time a transformation of a 6–8 to a 6–12 type cluster unit. The formation of the cluster cation goes along with a one‐electron oxidation of the cluster starting material. Furthermore, it adds a second entry to the so far very small group of M6 cluster compounds with organic ligands on the inner cluster sites.

Alcoholate and Mixed Alcoholate/Iodide Supported Hexanuclear Niobium Cluster Compounds with a Mixed Face-Bridged/Edge-Bridged Cluster Pair Example

“…1 is highly reactive towards air oxygen and water and also insoluble in most solvents. Furthermore, 1 H and 13 C NMR as well as IR measurements would not answer this question. Neutron diffraction would be the method of choice, but has not been applied because of the difficulties to access this method.…”

“…1 H-NMR ([D6]DMSO (H 2 O), 300 MHz, 300 K, ppm): δ = 3.17 (s, 72H, CH 3 OH), 4.08 (s, 24H, CH 3 OH). 13 C{1H} NMR ([D6]DMSO (H 2 O), 300 MHz, 300 K, ppm): δ = 48.56 (s, CH 3 OH).…”

“…Cluster compounds are known, which consist either of isolated (discrete) units or units that are linked through bridging ligands [12,13]. Solution-based chemical reactions allow for an exchange of ligands [14].…”

“…In most of these compounds, the six positions of the outer ligand sphere are primarily exchanged as a result of the ligand substitution. For M = Nb or Ta a large number of new compounds [M 6 X 12 L 6 ] with L = nitriles [15][16][17], amines [13,18,19], alcohols [14,17,20,21], water [22][23][24][25][26], etc. have been prepared and characterized.…”