Oxidative Dinuclear Addition of a Pd^I–Pd^I Moiety to Arenes: Generation of μ-η³:η³-Arene-Pd^II₂ Species

Abstract

We report the oxidative dinuclear addition of a Pd(I)-Pd(I) bond to arenes. The oxidative dinuclear addition products, which have a bi-π-allyl-type arene dipalladium(II) structure, were obtained from [2.2]paracyclophane, anthracene, tetracene, and pentacene. A systematic study of the reaction of [Pd(2)(CH(3)CN)(6)][BF(4)](2) with benzene and polyacenes showed that the larger polyacenes, tetracene and pentacene, afforded the oxidative dinuclear addition products, while benzene, naphthalene, and anthracene gave the π-sandwich Pd(I)-Pd(I) complexes.

A ladder polysilane as a template for folding palladium nanosheets

“…The synthesis of relatively small transition metal nanosheets has attained some success in organometallic and inorganic chemistry [6][7][8][9] . Among them, a novel methodology to synthesize Pd 3 to Pd 5 nanosheets was developed by Murahashi et al [10][11][12][13][14][15][16] using (poly)cyclic aromatic hydrocarbons as a template for the arrangement of Pd atoms in a two-dimensional sheet structure. The sandwich compound, [Pd 5 (naphthacene) 2 ] 2 þ , is the largest palladium nanosheet reported to date 10 .…”

Dinuclear palladium(I) sandwich complexes of furan and toluene

“…We recently reported the bridging p-coordination of pyrrole or indole to a dicationic Pd I -Pd I moiety derived from [Pd 2 (CH 3 CN) 6 ][BF 4 ] 2 (1) [5] (3) are stable in solution at ambient temperature, while the p-adducts of non-chelating, parent pyrrole or indole to mononuclear Pd II or Pd 0 moieties have not been isolated so far. As a part of our study on the bridging p-coordination of weakly coordinating arenes and hetero-arenes [4,5], here, we employed furan as the bridging substrate. Addition of furan (2 equiv) to 1 in CD 3 NO 2 at ambient temperature showed no sign of furan coordination in the 1 H NMR spectra.…”

“…3). A related dicationic bis-benzene dipalladium complex [Pd 2 (m-benzene) 2 (CH 3 CN) 2 ][BF 4 ] 2 was recently prepared directly from 1 in the presence of a large excess of benzene [4], but its structure has not been determined by X-ray structural analysis. A single crystal of 5 or 5 0 suitable for X-ray analysis was obtained by recrystallization from CH 3 NO 2 /toluene at -30 8C.…”

“…Representatively, the homoleptic nitrile dipalladium(I) complexes [Pd 2 (CH 3 CN) 6 ][X] 2 (1, X = BF 4 ; 1 0 , X = PF 6 ) have been developed as the substitutionally labile Pd-Pd complexes for studying coordination modes and reaction patterns of unsaturated substrates at a dinuclear palladium center [2,3]. By employing 1, indeed, several new coordination modes or reaction patterns have been recently disclosed in our laboratory, such as dinuclear palladation of arenes [4] and the bridging p-coordination of pyrrole and indole [5]. Agapie et al reported the bridging p-coordination of thiophene and furan to a diphosphinearene supported Pd I -Pd I moiety [6].…”

Bridging Coordination of Vinylarenes to Pd3‐ or Pd4 Cluster Sites

“…[3,4] However,c oordination behavior of vinylarenes to the bridging sites of Pd clusters has been virtually unexplored.O ur group recently developed organo-Pd 3 or Pd 4 clusters, which enable binding of substrates at their reactive Pd 3 -o rP d 4 clusters ites. [11][12][13][14][15][16][17][18] Notably,t he arene-Pd 3 -COT clusters undergo areneexchange reactions under gentle heating conditions, [5,6] althoughk nown m 3 -arene M 3 clusterso fo ther transition metals are inert towarda rene-exchange.T he half-sandwich Pd 4 sheet cluster supported by ab ackside COT ligand (Scheme 1) also providesaunique Pd 4 clusters ite, which accommodates naph-thalenei na nu nusual oxidative p-addition mode. [11][12][13][14][15][16][17][18] Notably,t he arene-Pd 3 -COT clusters undergo areneexchange reactions under gentle heating conditions, [5,6] althoughk nown m 3 -arene M 3 clusterso fo ther transition metals are inert towarda rene-exchange.T he half-sandwich Pd 4 sheet cluster supported by ab ackside COT ligand (Scheme 1) also providesaunique Pd 4 clusters ite, which accommodates naph-thalenei na nu nusual oxidative p-addition mode.…”