The reactivities of Mo cluster——A selective substitution reaction of the bridging(dtp)ligand and the crystal structure of{Mo_3S_4(μ-O_2CR)(dtp)_3(Py)}

The reaction of trinuclear molybdenum cluster{Mo_3S_4(μ-dtp)(dtp)_3(H_2O)}1[dtp= S_2P(OEt)_2]with RCO_2Na(R=H,CH_3)in the presence of Py gave the black compounds{Mo_3S_4(μ- O_2CR)(dtp)_3(Py)}(2,R=H,3,R=CH_3).Both compounds are characterized by X-ray crystallo- graphy.It is shown that crystals 2 and 3 belong to space group P with Z=2 and a=10.519(2),b= 12.121(2),c=15.757(2),α=93.27(1),β=94.63(1),γ=105.22(1)°,V=1925~3 for crystal 2,whereas a=9.556(2),b=14.067(7),c=15.914(9),α=101.41(4),β=101.44(4),γ=74.26(3)°,V=1994~3 for crystal 3.The final R factors are 0.041 and 0.048 for crystal 2 and 3 respectively.The structure analysis indicates that(O_2CR)^- ligand selectively substitutes the bridging(dtp)ligand.This type of Mo_3 cluster molecule where structure contains two species of bidentate ligand is for the first time to be obtained by us.