Syntheses and crystal structures of complexes [L′O(H2O)V(µ-O)WO2L]Cl(ClO4) and [L′(acac)MoIII(µ-O)MoVIO2L′][BPh4]2(L,L′= 1,4,7-triazacyclononane and its 1,4,7-trimethyl derivative; acac = pentane-2,4-dionate)

Abstract

Reaction of an equimolar mixture of [VCl₃L′] and [WO₃L]·3H₂O in MeOH–water (4 : 1) in the presence of air affords upon addition of NaClO₄ blue [L′O(H₂O)V^IV(µ-O)W^VIO₂L]Cl(ClO₄)1(L′= 1,4,7-trimethyl-1,4,7-triazacyclononane; L = 1,4,7-triazacyclononane). Crystals of 1 are monoclinic, space group P2₁/c, with a= 9.401(8), b= 20.61(1), c= 13.53(1)Å, β= 102.47(7)°, and Z= 4. The complex is an asymmetric, heterodinuclear species consisting of vanadyl VOL′(OH₂) and cis-LW^VIO₂ units which are asymmetrically bridged by an oxygen. A suspension of [Mo^IIIBr₃L′] and excess of sodium penta-2,4-dionate(acac) in water reacts in the presence of air with formation of the asymmetric mixed-valence species [L′(acac)Mo^III(µ-O)Mo^VIO₂L′]²⁺. The bis(tetraphenylborate) salt 2 crystallizes in the monoclinic space group P2₁/a with a= 18.589(9), b= 18.30(1), c= 20.432(9)Å, β= 104.73(4)° and Z= 4. The L′Mo^III(acac) and cis-L′MoO₂ units are linked by an asymmetric µ-oxo bridge with Mo^III–O_oxo and Mo^VI–O_oxo distances of 2.034(4) and 1.808(4)Å, respectively.