A NOVEL ROUTE TO DINUCLEAR HETEROLEPTIC RHODIUM(III) COMPLEXES OF 1,4,7-TRITHIACYCLONONANE

Abstract

New mono- and dinuclear Rh(III) complex cations of 1,4,7-trithiacyclononane (9S3), [Rh(9S3)(PPh(3))(I)(2)](+) and [(9S3)Rh(mu-SPh)(3)MCp*](2+) (M = Ph, Ir; Cp* = C-5(CH3)(5)), were prepared from the set of reaction systems utilizing [Rh(9S3)(CO)(PPh(3))](+) (1) as a synthon. Oxidative decarbonylation reaction of 1 with I-2 in CH2Cl2 gave the mononuclear diiodo cation as a perchlorate salt in good yield. In the presence of excess benzenethiol and NEt(3), [Rh(9S3)(PPh(3))(I)(2)](+) (2) in CH3CN undergoes substitution reaction, resulting in the formation of red insoluble neutral species 3 with the empirical formula of Rh(9S3)(SPh)(3).CH3CN. Treatment of 3 with [Cp*MCl(2)](2) (M = Rh, Ir)/AgClO4 in CH3CN afforded the above mentioned dinuclear cations. The compounds 2ClO(4) (A) and [(9S3)Rh(mu-SPh)(3)IrCp*](CLO(4))(2).0.5CH(3)CN.0.5Ch(2)Cl (B) were characterized by single-crystal X-ray diffraction studies. The compound A [B] crystallizes in the monoclinic space group P2(l)/a [P2(l)/n] with a = 15.416(3) [24.554(5)] Angstrom, b = 13.440(1) [15.706(2)] Angstrom, c 13.987(2) [11.725(1)] Angstrom, beta = 91.14(1) [98.36(2)] deg, V = 2897.4 [4473.6] Angstrom(3), Z = 4 [4], D-c = 2.05 [1.78] g cm(-3). Data were collected on an Enraf-Nonius CAD4 diffractometer, using Mo K alpha radiation, to maximum 2 theta = 48 [46] deg, giving 3850 [4669] unique reflections, and the structures were solved by heavy atom method for A [B]. The final discrepancy indices for A [B] were R (R(w)) = 0.038 (0.030) [0.067 (0.059)] for 3432 [2591] independent reflections with F > 6 sigma(F). The cation structures of A and B reveal the endo-tridentate ligating nature of 9S3 to Rh with varying Rh-S distances. Compound A adopts a cis geometry for two iodide groups around the octahedral Rh center. In the cation of B, a (Cp*Ir)(2+) moiety interacts with the Rh(9S3)(SPh)(3) unit, a unit suggested in 3, via three mu-SPh bridges, forming a heterodinuclear species with Ir...Rh interatomic distance of 3.244 Angstrom.