Aminolysis of [Cp*Ru(μ-OEt)]2 (Cp* = η5-C5Me5) with sulfonamides: Synthesis of neutral, zwitterionic, and anionic Cp*Ru terminal sulfonamido complexes

• Aminolysis of [Cp*Ru(μ-OEt)]2 with sulfonamides has been studied.
• The first terminal sulfonamido derivatives of the Cp*Ru fragment have been isolated.
• Anionic complexes of the type [Cp*Ru(sulfonamido)2]– are readily accessible.

The reaction of [Cp*Ru(μ-OEt)]2 (1) with sulfonamides affords terminal sulfonamido complexes via alkoxo-sulfonamido exchange and either symmetrical or unsymmetrical cleavage of the dimeric structure. The neutral phosphine-ligated monomeric complexes [Cp*Ru(NHTs)(PR3)n] (R = Cy, n = 1; R = Me, n = 2) are obtained by sequential treatment of 1 with TsNH2 and PR3 in THF. When the above reaction is conducted in the absence of PR3, a formally zwitterionic dinuclear complex [Cp*Ru−(NHTs)(μ-κ1:η6-NHTs)Ru+Cp*] is isolated. When the aminolysis of 1 with TsNH2 is conducted in toluene, trapping of a Cp*Ru+ fragment by a solvent molecule occurs to give the fully ionic complex salt [Cp*Ru(η6-toluene)][Cp*Ru(NHTs)2] (4a). The 16-electron anionic bis(tosylamido) complex in 4a reacts with CO or CNtBu, yielding the neutral 18-electron complexes [Cp*Ru(NHTs)(L)2] (L = CO, CNtBu) and a free tosylamide anion, the latter of which is isolated in the form of the complex salt [Cp*Ru(η6-toluene)][NHTs]. Mesylamido and N,N′-ditosylethylenediamido complexes analogous to 4a have also been synthesized.

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