Facile syntheses, isomeric structures, and chemical reactivity of diruthenium(I) complexes [Ru2(CO)4(MeCN)4L2]X2 (L = MeCN, PPh3, PPh2(allyl), PMe3; X- = PF6-, BF4-). A convenient route to 1,2-diamides and 1,2-dithiolates

Article abstract of DOI:10.1021/om00001a071

Alkylating agents such as Et₃O⁺X^- (X^- = PF₆^- or BF₄^-) readily remove the bridging acetate groups of [Ru₂(CO)₄(O₂CMe)₂L₂] at ambient temperature to give the versatile complexes [Ru₂(CO)₄(NCMe)₄L₂]X₂ (L = MeCN (1), PPh₃ (2), PPh₂(allyl) (3), and PMe₃ (4)). The crystal structures of 3 and 4 were determined by X-ray crystallography: [3][BF₄]₂, a = 20.292(6), b = 17.223(7), c = 15.186(3), β = 113.324(18)°, V = 4873(3) A?³, monoclinic C2/c, Z = 4, refined to R = 0.045, R_w = 0.048, and GOF = 2.27. [4][BF₄]₂, a = 12.570(4), b = 14.251(5), c = 18.773(6) A?, β = 104.96(3)°, V = 3251(9) A?³, monoclinic P2₁/n, Z = 4, refined to R = 0.044, R_w = 0.044, and GOF = 1.53. Although 3 adopts a trans-staggered structure, 4 is in a cis-staggered geometry. The high reactivity of 1-4 is demonstrated via the cation-anion annihilation between 2²⁺ and the doubly deprotonated anion, (E-E)^2-, to give [Ru₂(CO)₄-{μ-η²,η ²-(E-E)}(PPh₃)₂] ((E-E)^2- = 1,2-(NH)₂C₆H₄^2- (7); 2,3-(NH)₂C₁₀H₆^2- (8); 1,2-(NH)₂-4,5-Cl₂C₆H₂^2- (9); 1,2-(NH)₂-4,5-Me₂C₆H₂ (10); 9,10-(NH)₂C₁₄H₈ (11); and 1,2-S₂C₆H₄^2- (12)). The structures of 7-12 were also confirmed by an X-ray single-crystal structure of 12: a = 11.155(1), b = 21.302(2), c = 10.183(2) A?, α = 93.65(1), β = 113.43(1), γ = 101.19(1)°, V = 2151.2(6) A?³, triclinic P1, Z = 2, refined to R = 0.038, R_w = 0.046, and GOF = 2.81. The Ru-Ru distances are 2.8647(11) A? in 3, 2.861(1) A? in 4, and 2.6767(5) A? in 12.