Heteronuclear Rhodium, Palladium, Platinum, and Gold Organoimido Complexes from Dinuclear Organoamido Rhodium Precursors

Abstract

Treatment of the organoamido complexes [Rh(2)(mu-4-HNC(6)H(4)Me)(2)(L(2))(2)] (L(2) = 1,5-cyclooctadiene (cod), L = CO) with nBuLi gave solutions of the organoimido species [Li(2)Rh(2)(mu-4-NC(6)H(4)Me)(2)(L(2))(2)]. Further reaction of [Li(2)Rh(2)(mu-4-NC(6)H(4)Me)(2)(cod)(2)] with [Rh(2)(mu-Cl)(2)(cod)(2)] afforded the neutral tetranuclear complex [Rh(4)(mu-4-NC(6)H(4)Me)(2)(cod)(4)] (2), which rationalizes the direct syntheses of 2 from [Rh(2)(mu-Cl)(2)(cod)(2)] and Li(2)NC(6)H(4)Me. Reactions of [Li(2)Rh(2)(mu-4-NC(6)H(4)Me)(2)(CO)(4)] with chloro complexes such as [Rh(2)(mu-Cl)(2)(CO)(4)], [MCl(2)(cod)] (M = Pd, Pt), and [Ru(2)(mu-Cl)(2)Cl(2)(p-cymene)(2)] afforded the homo- and heterotrinuclear complexes PPN[Rh(3)(mu-4-NC(6)H(4)Me)(2)(CO)(6)] (5; PPN=bis(triphenylphosphine)iminium), [(CO)(4)Rh(2)(mu-4-NC(6)H(4)Me)(2)M(cod)] (M = Pd (6), Pt(7)) and [(CO)(4)Rh(2)(mu-4-NC(6)H(4)Me)(2)Ru(p-cymene)] (8), while the reaction with [AuCl(PPh(3))] gave the tetranuclear compound [(CO)(4)Rh(2)(mu--4-NC(6)H(4)Me)(2)[Au(PPh(3))](2)] (9). The structures of complexes 6, 8, and 9 were determined by X-ray diffraction studies. The anion of 5 reacts with [AuCl(PPh(3))] to give the butterfly cluster [[Rh(3)(mu-4-NC(6)H(4)Me)(2)(CO)(6)]Au(PPh(3))] (10), in which the Au atom is bonded to two rhodium atoms. Reaction of the anion of 5 with [Rh(cod)(NCMe)(2)](BF(4)) gave the tetranuclear complex [Rh(4)(mu-4-NC(6)H(4)Me)(2)(CO)(6)(cod)] (11) in which the Rh(cod) fragment is pi-bonded to one of the arene rings, while the reaction of the anion of 5 with [PdCl(2)(cod)] afforded the heterotrinuclear complex 6 through a metal exchange process.

Intervalent Bis(μ‐aziridinato)MIIMI Complexes (M=Rh, Ir): Delocalized Metallo‐Radicals or Delocalized Aminyl Radicals?

“…+ ) and the hydride compound [(cod)(H)IrA C H T U N G T R E N N U N G (m-az) 2 IrA C H T U N G T R E N N U N G (cod)] ( [6] + ). Addition of small amounts of acetonitrile to dichloromethane solutions of [3] + and [4] + triggers a fast disproportionation reaction in both cases to produce equimolecular amounts of the starting materials 3 and 4 and metalÀmetal bonded M II ÀM II species.…”

“…[4] A survey of the literature on this topic made us aware of the absence of data about the redox behavior of dinuclear Rh I and Ir I amido derivatives. Dinuclear amido complexes of these metals are well-known, [5] and some of them have been reported as useful precursors for the synthesis of imido complexes, [6] for the transfer of the amido group to olefins, [7] and in catalyzed CÀC bond formation reactions. [8] Further, studies of the oxidative addition reactions of halocarbons allowed the synthesis of Ir I /Ir III derivatives [9] and the detection of S N 2 profiles in the activation of chloro compounds.…”

“…Addition of ligands, such as acetonitrile, to dichloromethane solutions of [6]PF 6 did not lead to insertion of hydride into the metal-olefin bond, neither to hydrogen transfer to the neighboring nitrogen atom to form aziridine. Nevertheless, solutions of complex [6]PF 6 in [D 6 ]acetone show a slow disappearance of the resonance corresponding to the hydride due to an exchange with deuterium.…”

“…(M= Rh, 3; Ir, 4), in both dichloromethane and acetonitrile suggest that the formation of the cationic com- 6 , suitable for X-ray diffraction studies, were obtained. The structure of one of the independent cations [3] + is shown in Figure 6 (for the isostructural complex [4]PF 6 see the Supporting Information) and selected bond lengths and angles are given in Table 3 (the data of the second independent molecule within brackets).…”

“…Nevertheless, solutions of complex [6]PF 6 in [D 6 ]acetone show a slow disappearance of the resonance corresponding to the hydride due to an exchange with deuterium. The acidic character of this hydride in complex [6] + is clearly shown by the quantitative transformation into complex 4 by treatment with hexamethyltetraamine (hmta).…”