The syntheses of metallomacrocycles containing unsymmetrical bridging ligands and the crystal structures of DL -[Mo{HB(3,5-Me2C3HN2)3}(NO)(OC6H4CH2CH2O-4)]2·2CH2Cl2 and DL -[W{HB(3,5-Me2C3HN2)3}(NO)(OC6H3NO2-4-CH2CH2O-3)]2· CH2Cl2;

Abstract

Metallomacrocycles containing {M(NO)(Tp^Me2)} [Tp^Me2 = HB(3,5-Me₂C₃HN₂)₃; M = Mo or W] have been synthesized by direct reaction between [M(NO)(Tp^Me2)I₂] and a heterotopic ligand HE–E′H {1,x-HOC₆H₄XOH (x = 3, X = CO; x = 3 or 4, X = CH₂ or CH₂CH₂)} in the presence of NEt₃. Only DL and meso isomers were isolated from the reactions where M = Mo, x = 4 and X = CO or CH₂CH₂ but both DL and meso and syn and anti isomers from the other reaction mixtures. Stereo-controlled synthetic routes to syn and anti isomers containing the OC₆H₄CH₂O-3 bridging ligand were developed through formation of [M(NO)(Tp^Me2)(OC₆H₄CHO-3)]₂ (M = Mo or W) followed by reduction to [M(NO)(Tp^Me2)(OC₆H₄CH₂OH-3)]₂ and subsequent reaction with [M′(NO)(Tp^Me2)I₂] (M′ = W or Mo) to give [{M(NO)(Tp^Me2)}(μ-OC₆H₄CH₂O-3)₂{M′(NO)(Tp^Me2)}]. The trinuclear complex [{Mo(Tp^Me2)(NO)}(μ-OC₆H₄CH₂O-3)₂{W(Tp^Me2)(NO)}₂(μ-1,3-OC₆H₄O)] was obtained from the reaction of [Mo(NO)(Tp^Me2)(OC₆H₄CH₂OH-3)]₂ with the binuclear complex [{W(NO)(Tp^Me2)I}₂(μ-1,3-O₂C₆H₄)]. The crystal structures of DL -[Mo(Tp^Me2)(NO)(OC₆H₄CH₂CH₂O-4)]₂ and [W(Tp^Me2)(NO)(OC₆H₃NO₂-4-CH₂CH₂O-3)]₂ were established.