Thiolate coordination in binuclear oxomolybdenum(V) complexes. The x-ray crystal structures of the alkylammonium salts of [Mo 2O 2(OCH 3)(SCH 2CH 2CH 2S) 3] − and [Mo 2O 2(SCH 2CO 2) 4] 2−

Abstract

Reaction of [ n-Bu 4N] 2[Mo 2O 7] with propane-1,3-dithiol in methanol yields the triply-bridged binuclear complex [ n-Bu 4N][Mo 2O 3(OCH 3)(SCH 2CH 2CH 2S) 3] ( 1). Complex 1 exhibits the confacial bioctahedral geometry characteristic of this class of complexes. In contrast, the reaction of [ n-Bu 4N] 4[Mo 8O 26] with 2-mercaptoacetic acid and triethylamine in methanol results in the isolation of a complex [Et 3NH] 2[Mo 2O 2(SCH 2CO 2) 4] ( 2), representing the first example of a new class of binuclear molybdenum(V) species. The structure is characterized by a ‘ trans-planar’ [Mo 2O 2S 2(thiolate)] 4+ core and an unusually long Mo ⋯ Mo distance of 3.078(1) Å. Crystal data. Complex 1: triclinic space group P 1 , a = 9.310(2), b = 11.328(2), c = 19.954(3) Å, α = 74.93(1), β = 78.19(1), γ = 81.53(1)°, V = 1979.2(10) Å 3, Z = 2, D calc, = 1.369 g cm 3−; structure solution and refinement based on 5292 reflections, R = 0.0570. Complex 2: monoclinic space group P2 1/ n, a = 10.861(4), b = 13.559(4), c = 11.011(4) Å, β = 104.14(2)°, V = 1572.1(11) Å 3, Z = 2, D calc, = 1.664 g cm −3; 2133 reflections, R = 0.0560.