Inorganic Chemistry, Vol.46, No.21, 8939-8949, 2007
On the reactivity toward ketones of new methyl amino complexes of Rh(III) and Ag(I). Synthesis of ortho-rhodiated acetophenone methyl imine complexes
MeNH2 reacts with silver salts AgX (2:1) to give [Ag(NH2Me)(2)]X [X = TfO = CF3SO3 (1 center dot TfO) and ClO4 (1.ClO4)]. Neutral mono(amino) Rh(III) complexes [Rh(Cp*)Cl-2(NH2R)] [R = Me (2a), To = C6H4Me-4 (2b)] have been prepared by reacting [Rh(Cp*)Cl(mu-CI)](2) with RNH2 (1:2). The following cationic methyl amino complexes have also been prepared: [Rh(Cp*)Cl(NH2Me)(PPh3)]TfO (3-TfO), from [Rh(CP*)Cl-2(PPh3)] and 1 center dot TfO (1:1); [Rh(Cp*)Cl(NH2R)(2)]X, where R = Me, X = Cl, (4a-Cl), from [Rh(Cp*)Cl(mu-Cl)](2) and MeNH2 (1:4), or R = Me, X = ClO4 (4a center dot ClO4), from 4a center dot Cl and NaClO4 (1:4.8), or R = To, X = TfO (4b center dot TfO), from [Rh(CP*)Cl(mu-Cl)](2), ToNH(2) and TITfO (1:4:2); [Rh(Cp*)(NH2Me)((t)Bubpy)](TfO)(2) ((t)Bubpy = 4,4'-di-tert-butyl-2,2'-bipyridine, 5-TfO), from 2a, TITfO and (t)Bubpy (1: 2:1); [Rh(Cp*)(NH2Me)(3)](TfO)(2) (6 center dot TfO) from [Rh(CP*)Cl(mu-Cl)](2) and 1 center dot TfO (1:4). 2-6 constitute the first family of methyl amino complexes of rhodium. 1 and 4a center dot ClO4 react with acetone to give, respectively, the methyl imino complexes [Ag{N(Me)=CMe2}(2)]X [X = TfO (7 center dot TfO), ClO4 (7 center dot ClO4)], and [Rh(Cp*)Cl(Me-imam)]ClO4 [8 center dot ClO4, Meimam = N,N'-N(Me)=C(Me)CH2C(Me)(2)NHMe]. 7 center dot X (X = TfO, ClO4) are new members of the small family of methyl acetimino complexes of any metal whereas 8 center dot ClO4 results after a double acetone condensation to give the corresponding bis(methyl acetimino) complex and an aldol-like condensation of the two imino ligands. The acetimino complex [Ag(NH=CMe2)(2)]ClO4 reacts with [Rh(Cp*)Cl(imam)]ClO4 [1:1, imam = N,N'-NH=C(Me)CH2C(Me)(2)NH2] to give [Rh(Cp*)(imam)(NH=CMe2)](ClO4)(2) (9a center dot ClO4). 8 center dot ClO4 reacts with AgClO4 (1:1) in MeCN to give [Rh(Cp*)(Me-imam)(NCMe)](ClO4)(2) (9b center dot ClO4), which in turn reacts with XyNC (Xy = C6H3Me2-2,6) or with MeNH2 (1:1) to give [Rh(Cp*)(Me-imam)L](ClO4)(2) [L = XyNC (9c center dot ClO4), MeNH2 (9d center dot ClO4)]. 6 center dot TfO reacts with acetophenone to give [Rh(Cp*){C,N-C6H4C(Me)=N(Me)-2}(NH2Me)]TfO (10a-TfO), the first complex resulting from such a condensation and cyclometalation reaction. In turn, 10a center dot TfO reacts with isocyanides RNC (1:1) at room temperature to give [Rh(Cp*){C,N-C6H4C(Me)=NMe-2}(CNR)]TfO [R = Bu-t (10b center dot TfO), Xy (10c center dot TfO)], or 1:12 at 60 degrees C to give [Rh(Cp*){C,N-C(=NXy)C6H4C(Me)=N(Me)-2}(CNXy)]TfO (11 center dot TfO). The crystal structures of 9a center dot ClO4-acetone-d(6), 9c center dot ClO4, and 10a center dot TfO have been determined.