Dual reactivity pattern of Mn(I) carbyne complexes Cp(CO)2Mn+ ≡C–R (R = Ar, Alk) vs. dppm: Subtle balance between double intramolecular nucleophilic addition and nucleophilic addition followed by migratory CO insertion

Publication date: Available online 28 December 2017 Source:Journal of Organometallic Chemistry Author(s): Dmitry A. Valyaev, Kamil I. Utegenov, Vassily V. Krivykh, Jérémy Willot, Nikolai A. Ustynyuk, Noël Lugan The Mn(I) cationic carbyne complexes [Cp(CO)2Mn+≡C–R]BX4 (R = Ph, Tol, Me, Bn; X = F, Cl, Ph) react with bis(diphenylphosphino)methane to afford selectively either cyclic λ5-1,3-diphosphetium semi-ylides [RC–P+Ph2CH2P+Ph2)]BPh4 ([R 4]BPh4; R = Ph, Tol), or Mn(I) complexes [Cp(CO)Mn(η3-(P,C,C)-Ph2PCH2P+Ph2C(R)=C=O)]BX4 ([R 5]BX4; R = Me, X = Ph; R = Bn, X = F) featuring unprecedented phosphonioketene ligands depending on the nature of the carbyne substituent, aryl or alkyl, respectively. The selective formation of these products is tentatively rationalized through the key formation of a transient cationic Mn(I) phosphoniocarbene complexes [Cp(CO)2Mn=C(R)PPh2 +CH2PPh2]BX4 bearing a pendent phosphine moiety. The molecular structures of semi-ylide [Ph 4]BPh4 and complex [Bn 5]BF4 were elucidated by single-crystal X-ray diffraction. Graphical abstract

Source: Journal of Organometallic Chemistry - December 29, 2017 Category: Chemistry Source Type: research