Electrochemically induced transformations of bi- and trinuclear heterometallic vinylidene complexes containing Re, Pd and Fe

Abstract

Redox-induced transformations of bi-(Cp(CO) 2 RePd(μ-C=CHPh)(PPh 3) 2 (2), Cp(CO) 2 RePd(μ-C=CHPh)(P-P) [P-P =  2-Ph 2 P(CH 2) 2 PPh 2 (dppe) (3),  2-Ph 2 P(CH 2) 3 PPh 2 (dppp) (4)], Cp(CO) 2 ReFe(μ-C=CHPh)(CO) 4 (5) and trinuclear (Cp(CO) 2 ReFe 2 (μ 3-C=CHPh)(CO) 6 (6), CpReFePd(µ 3-C=CHPh)(CO) 5 (P-P) [P-P = dppe (7), dppp (8)] heterometallic vinylidene complexes derived from Cp(CO) 2 Re=C=CHPh (1) were investigated by electrochemical methods. The oxidation processes of clusters 7 and 8 were studied by EPR spectroscopy. The electrochemical properties of clusters 7 and 8 were shown to depend on the nature of the chelate diphosphine ligand at the palladium center in contrast to complexes 3 and 4. The oxidation of complexes 2-4 was found to result in the Re-Pd, Pd-С 1 bond cleavage and formation of rhenium complex 1 and Pd-containing fragments. The oxidation of 7 and 8 resulted in the formation of the radical cations 7 +• and 8 +• , which gradually transformed into a number of intermediate products: Cp(CO) 2 RePd(μ-C=CHPh)(P-P), [Fe(CO) 3 ] +• , [CpReFe 2 (µ 3-C=CHPh)(CO) 6 ] +• and others. The final products of their oxidation in both cases were triangular clusters (CO) 8 Fe 2 Pd(P-P) [P-P = dppe (9), dppp (10)] and rhenium complex 1. The molecular structure of cluster 7 was established by X-ray diffraction analysis.

Chemistry of vinylidene complexes. XXV. Synthesis and reactions of binuclear µ-vinylidene RePt complexes containing phosphite ligands. Spectroscopic, structural and electrochemical study

“…The bis-vinylidene rhenium complex was shown to be generated only under the treatment of Cp(CO) 2 Re=C=CHPh with [(η 5 -C 5 H 5 ) 2 Fe]BF 4 /triethylamine couple in dichloromethane at room temperature [39]. Moreover, the controlled potential electrolysis at a Pt-electrode of µ-vinylidene RePt and RePd complexes with chelate diphosphine ligands resulted in only the formation of Cp(CO) 2 Re=C=CHPh, the second pathway yielding the rhenium cation-radical [Cp(CO) 2 Re=C=CHPh] +• and its dehydrodemirization product Cp(CO) 2 Re=C=C(Ph)-C(Ph)=C=Re(CO) 2 Cp wasn't observed at all [28,38,41]. Therefore, the formation of Cp(CO) 2 Re=C=C(Ph)-C(Ph)=C=Re(CO) 2 Cp under the electrochemical conditions can be explained by specific behavior of the generated cation radicals [Cp(CO) 2 Re=C=CHPh] +• and the platinum fragments on the surface of the platinum electrode.…”

EPR Spectroscopy Study of the Radical Cation Cluster (η⁵-C₅H₅)(CO)₅ReFePt(μ₃-C=CHPh)(η²-Ph₂P(CH₂)₂PPh₂)

“…[P-P = Ph 2 P(CH 2 ) n PPh 2 , n = 2 (dppe), 3 (dppp)], выявить и охарактеризовать их относительно устойчивые катион-радикалы [10,11].…”

Electrochemical Study of Phenylvinylidene Clusters Containing ReFePt Metal Cores and Chelate Diphosphine Ligands

“…Ранее нами изучены редокс-свойства фенилвинилиденовых Pd-содержащих трехъядерных кластеров CpReFePd(µ 3 -C=CHPh)(CO) 5 (P-P) [P-P = Ph 2 P(CH 2 ) n PPh 2 , n = 2 (dppe), 3 (dppp)] и их биядерных предшественников Cp(CO) 2 RePd(μ-C=CHPh)(P-P), а также биядерных Pt-содержащих комплексов Cp(CO) 2 RePt(μ-C=CHPh)(P-P) с хелатными дифосфиновыми лигандами P-P = dppe, dppp [25][26][27]. Дальнейшие превращения образующихся анион-радикалов 1 Список литературы…”