Electrochemical interactions in binuclear molybdenum and tungsten nitrosyl complexes incorporating saturated n-alkanediolate bridging ligands.: Crystal structures of [Mo(NO)(TpMe2)I{O(CH2)2OCOCH3}] and [W(NO)(TpMe2)I2] • 0.5I2 • 0.5C6H5CH3

A series of bimetallic ([{M(NO)(Tpe(Me2))X}(2) (Q)] [Tp(Me2) = tris(3,5-dimethylpyrazolyl)borate; M = Mo, X Cl, Q = O(CH2)(n)O, n = 3, 5, 6, or OCH2(CF2)(3)CH2O; M = Mo, X = I, n = 3 or 4; M = W, X = Cl, n = 3-6, or OCH2(CF2)(3)CH2O; M = W, X = Br, n = 2]), and a number of monometallic complexes ([M(NO)(Tp(Me2))X(QH)] [M = Mo, X = Cl, Q = O(CH2)(n)O, n = 3, or OCH2(CF2)(3)CH2O; M = W, X = Br, n = 2]) were prepared. The heterobimetallic complex [[Mo(NO)(Tp(Me2))Br}O(CH2)(2)O{W(NO)(Tp(me2))Br}] was also obtained. All compounds were characterised by elemental and mass analyses, H-1 NMR and IR spectroscopy. Electrochemical studies (CV and DPV) of the bimetallic species reveal that the metal-metal interactions decrease by ca. 100 mV per CH2 group with increased length for C-2 to C-4 bridges and become undetectable for complexes with bridges longer than C-4. The substitution of fluorine into the C-5 bridge causes the effect to become measurable due to easier polarisation of the sigma-bond framework. The crystal structures of [Mo(NO)(Tpme2)I{O(CH2)(2)OCOCH3}] and [W(NO)(Tp(Me2))I-2] center dot 0.5I(2) center dot 0.5C(6)H(5)CH(3) were determined. (c) 2007 Elsevier Ltd. All rights reserved.