Crystal Structures of trans‐[Ta₆Cl₁₂(OH)₄(H₂O)₂] · 10 H₂O and (NMe₄)₂[Ta₆Cl₁₂(OH)₆] · 21 H₂O

Abstract

The compounds trans‐[Ta6Cl12(OH)4 (H2O)2] · 10 H2O 1, (NMe4)2[Ta6Cl12(OH)6] · 21 H2O 2 and Na2[Ta6Cl12(OH)6] · 16 H2O 3 containing octahedral tantalum chloro clusters were isolated from alkaline methanol/water solutions of [Ta6Cl12]4+. Crystal structures were solved for 1 and 2. Crystal data: 1, monoclinic, space group P21/c (No. 14), a = 938.5(2) pm, b = 1220.3(2) pm, c = 1391.7(4) pm, β = 103.87(2)°, V = 1547.5(6) × 106 pm3, Z = 2; 2, rhombohedral, space group R3 (No. 148), a = 1201.4(2) pm, c = 3110.8(6) pm, V = 3888.5(12) × 106 pm3, Z = 3; 3, cubic F lattice, a = 1451(2) pm, V = 3055(13) × 106 pm3, Z = 4. The cluster in 1 contains the neutral, mixed‐coordinated trans‐[Ta6Cl12(OH)4 (H2O)2] cluster with TaOH and TaOH2 distances of 210.4(5) pm and 214.5(5) pm, respectively. One coordinated H2O molecule from one cluster and a coordinated OH− group from a neighbouring cluster form H3O2− intercluster bridges with the O …︁ HO distance 253.7(7) pm. Twelve TaCl (bridging) distances range from 244.1(2) to 245.2(2) pm. The structure of 2 is built of [Ta6Cl12(OH)6]2− anions, NMe4+ cations and water molecules, the latter linked to the anions by hydrogen bonds.

A Family of Octahedral Rhenium Cluster Complexes [Re6Q8(H2O)n(OH)6 - n]n - 4 (Q = S, Se; n = 0−6): Structural and pH−Dependent Spectroscopic Studies

“…Earlier, similar exceptionally short intermolecular hydrogen bonds were found in the related octahedral aquahydroxo cluster complexes NEt 4 [Nb 6 C1 12 (OH) 3 (H 2 O) 3 ]·3H 2 O and trans -[Ta 6 Cl 12 (OH) 4 (H 2 O) 2 ]·10H 2 O, where strong hydrogen bonds are formed between the coordinated water molecule of one cluster complex and the coordinated OH - group from a neighboring one, with O···O distances equal to 2.54 Å. Their values are very close to the intercluster hydrogen bond lengths found in the rhenium aquahydroxo complexes 1 and 2 presented here and fall in the range of exceptionally short intermolecular hydrogen bonds usually formed between the OH - ligand coordinated to one metal atom and the H 2 O ligand coordinated to another metal atom, thus forming the bridging ligand H 3 O 2 - , as discussed by Bino et al − …”

[Ta6Cl12(PrCN)6][(Ta6Cl12)Cl6]·2PrCN, A Compound with Homonuclear Mixed-Charge Cluster Units [Ta6Cl12]2+ and [Ta6Cl12]4+

“…When the [Ta 6 Cl 12 L 6 a ] 4+ unit is terminally ligated with oxygen donor ligands (L a ), the geometry of the cluster is dependent on the nature of the oxygen donor atoms and the particular hydrogen bonding system involved. Usually, the shortest Ta−O a bonds are associated with long Ta−Ta bond distances . In the absence of any hydrogen bonds involving N atoms from coordinated PrCN molecules, as well as in the presence of only very weak intermolecular contacts involving crystalline PrCN [N(4)···H(10c)−C(10)#1 of 3.337 Å], the interatomic distances observed for the title compound represent the geometry for [Ta 6 Cl 12 ] 2+ and [Ta 6 Cl 12 ] 4+ units free of the influence of hydrogen bonding effects.…”

Reduced Zirconium Halide Clusters in Aqueous Solution

“…The chemistry of centered hexazirconium halide clusters has been extended into solution via reactions in which clusters are excised from solid-state precursors. − Until recently, however, solvents for such reactions were limited to aprotic organic solvents with high dielectric constant (e.g., acetonitrile and sulfolane) and ionic liquids (AlCl 3 /1-ethyl-3-methylimidazolium chloride, AlCl 3 /ImCl). On the other hand, the structurally related niobium and tantalum halide cluster unit, [M 6 Cl 12 ] n + (M = Nb, Ta; n = 2, 3, 4), are stable in deoxygenated water, and their aqueous chemistry has been explored. − …”