The x-ray crystal structure of NaK3[Mo(CN)7]· 2H2O and the structure of its anion in aqueous solution

The Heptacyanotungstate(IV) Anion: A New 5 d Transition‐Metal Member of the Rare Heptacyanometallate Family of Anions

“…Similar distortions were noted for K 4 19] In the solid, state compound 1 exhibits two sharp and strong n(CN) stretches at 2110 and 2079 cm À1 (Figure S2 a) confirming that the geometry of the [W IV (CN) 7 ] 3À anion is close to the ideal pentagonal bipyramid (IR selection rules for D 5h allow only two vibrations:A 2 '' and E 1 '). Similar distortions were noted for K 4 19] In the solid, state compound 1 exhibits two sharp and strong n(CN) stretches at 2110 and 2079 cm À1 (Figure S2 a) confirming that the geometry of the [W IV (CN) 7 ] 3À anion is close to the ideal pentagonal bipyramid (IR selection rules for D 5h allow only two vibrations:A 2 '' and E 1 ').…”

Synthesis and Redox‐Induced Structural Isomerization of the Pentagonal Bipyramidal Complexes [W(CN)5(CO)2]3− and [W(CN)5(CO)2]2−

“…Consistent with D 5h symmetry in solution, the 13 C NMR spectrum of the 13 CN-labeled complex in CDCl 3 exhibits a single resonance centered at d = 134.5 ppm with splitting indicative of a 183 W-13 C coupling constant of 69.7 Hz (see Figure S4). As expected for a pentagonal bipyramidal complex of tungsten(II) with a low-spin d 4 Figure 1, right).…”

“…The mean W À C ax distance was found to be approximately 0.2 shorter than the mean WÀC eq distance, consistent with the stronger p-acceptor ligand occupying the axial sites. Note that this is a significant axial contraction when compared with [Mo(CN) 7 ] 4À [13] and [Re(CN) 7 ] 3À [7] which show no differences between the axial and equatorial bonds within experimental error. For each molecule, the distortion away from a perfect pentagonal bipyramidal coordination of the W II center occurs amongst the cyanide ligands, one of which (the rightmost in Figure 1) is raised above the mean equatorial plane by approximately 108, and one of which (the foremost) is pushed below the plane by [8] for two crystallographically independent molecules in 1: W-C(O) 1.99(2), W-C(N) 2.17(3), C eq -W-C eq 73(1), C ax -W-C ax 177.5(4), W-C-O 177(1), W-C-N 177(2).…”

“…Herein, we demonstrate the use of a mixed cyanide/carbonyl ligand set [10] 3À in the asymmetric unit, each adopting a slightly distorted pentagonal bipyramidal geometry (see Figure 1, left). [12] In both molecules, the two carbonyl groups were tentatively assigned to the axial sites on the basis of comparisons of thermal ellipsoids, W À C and W···O/N distances, and refinement residual factors. 3À [7] which show no differences between the axial and equatorial bonds within experimental error.…”

“…X-ray analysis of a single crystal of 1 revealed two molecules of [W(CN) 5 (CO) 2 ] 3À in the asymmetric unit, each adopting a slightly distorted pentagonal bipyramidal geometry (see Figure 1, left). [12] In both molecules, the two carbonyl groups were tentatively assigned to the axial sites on the basis of comparisons of thermal ellipsoids, W À C and W···O/N distances, and refinement residual factors. The mean W À C ax distance was found to be approximately 0.2 shorter than the mean WÀC eq distance, consistent with the stronger p-acceptor ligand occupying the axial sites.…”