Abstract

Treatment of a or b with Li-2[PdCl4] in methanol at room temperature for 48 h, gave the tetrametallic chlorine bridged complexes [Pd{CpFe[eta(5)-C5H2{C(H)O(CH2)(3)O}C(H)=NR]}(mu-Cl)](2), 1a and 1b, containing a cyclic acetal on the metallated cyclopentadienyl ring. The reactions of 1a and 1b with the Ph2P(CH2)(n)PPh2 diphosphines in a 1:1 ratio gave the tetrametallic species [{Pd{CpFe[eta(5)-C5H2{C(H) O(CH2)(3)O}C(H)=NR]}(Cl)}(2)(mu-Ph2P(CH2) nPPh(2))], n = 1-4 as appropriate, 2a-5a and 2b-5b, with the diphosphine in a bridging mode and terminal chlorine ligands. Treatment of 1a and 1b with monophosphines yielded the dimetallic compounds [Pd{CpFe[eta(5)-C5H2{C(H)O(CH2)(3)O}C(H)=NR]}(Cl)(L)] (L = PPh3, PPh2Me, PPh2Et) 6a-8a and 6b-7b. Reaction of the phosphine derivatives with aqueous acetic acid gave the corresponding functionalized compounds with transformation of the 1,3-dioxane ring into a formyl group on the metallated ring 9a-15a and 9b-14b. Reaction of 8a with acetic acid in methanol gave [Pd{CpFe[eta(5)-C5H2{CH(OMe)(2)}C(H)=N-2,4,6-Me3C6H2]}(Cl)(PPh2Et)] 16a, after a transacetalization reaction with an acetal moiety -CH(OMe)(2) on the metallated five-membered ring. The molecular structure of compound 16a has been determined by X-ray diffraction analysis. (C) 2013 Elsevier B. V. All rights reserved.