Polymerization of Mo V : Synthesis and Characterization of a Dinuclear Mo V and a Hexanuclear Mixed‐Valence Mo V /Mo VI Complex

1,3,5‐Trideoxy‐1,3,5‐tris(dimethylamino)‐ cis ‐inositol (tdci = L) reacts with MoCl 5 in a mixture of MeOH/water at 80 °C to yield the pale purple syn ‐[Mo 2 O 4 H(L) 2 ]Cl 3 · 14.5H 2 O ( 1 Cl 3 · 14.5H 2 O). Crystal data: space group P 2 1 / n , a = 8.797(2) Å, b = 25.439(5) Å, c = 23.077(5) Å, β = 90.44(3)°, V = 5164(2) Å 3 , Z = 4 for C 24 H 84 Cl 3 Mo 2 N 6 O 24.5 . In solutions of the dinuclear 1 3+ , which were exposed to air for several weeks, slow formation of deep red crystals containing a novel, hexanuclear, mixed‐valence complex of composition [Mo 4 O 8 (L) 2 (MoO 4 ) 2 ] · ≈27H 2 O ( 2· ≈27H 2 O) was observed. The tetranuclear core of complex 2 was unambiguously identified by MS‐FAB spectrometry, and the entire structure was characterized by a crystal‐structure analysis: space group P 2 1 / c , a = 12.224(2) Å, b = 15.986(3) Å, c = 14.220(3) Å, β = 98.95(3)°, and V = 2744.9(9) Å 3 , Z = 2 for C 24 H 109 Mo 6 N 6 O 49.5 . The structure of the hexanuclear mixed‐valence complex 2 contains the well‐known [Mo 4 O 8 ] 4+ core in which two of the four Mo V centers bond to Mo VI O 4 units by corner sharing. The remaining two Mo V centers are each chelated by a tdci ligand. Cyclic voltammetry confirmed an irreversible reduction and oxidation of 1 3+ at a potential of about –1.15 V and +0.54 V vs. NHE, respectively. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)