Versatile reactivity of dioxaneferrocenylimine palladacycles by controlled acid hydrolysis. Crystal and molecular structure of [Pd{CpFe[η5-C5H2{CH(OMe)2}C(H)N-2,4,6-Me3C6H2]}(Cl)(PPh2Et)]

• Published in: Journal of organometallic chemistry Vol. 740; pp. 92 - 97
• Main Authors: Martínez, Javier, Mariño, Marta, Caamaño, Marcelo, Pereira, Ma Teresa, Ortigueira, Juan M., Gayoso, Eduardo, López-Torres, Margarita, Vila, José M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.09.2013
• Subjects: Acetal; Crystal structure; Ferrocene; Palladium; Phosphine; Schiff base; Schiff base; Acetal; Palladium; Phosphine; Ferrocene; Crystal structure
• ISSN: 0022-328X; 1872-8561
• DOI: 10.1016/j.jorganchem.2013.05.007

Treatment of a or b with Li2[PdCl4] in methanol at room temperature for 48 h, gave the tetrametallic chlorine bridged complexes [Pd{CpFe[η5-C5H2{C(H)O(CH2)3O}C(H)NR]}(μ-Cl)]2, 1a and 1b, containing a cyclic acetal on the metallated cyclopentadienyl ring. The reactions of 1a and 1b with the Ph2P(CH2)nPPh2 diphosphines in a 1:1 ratio gave the tetrametallic species [{Pd{CpFe[η5-C5H2{C(H)O(CH2)3O}C(H)NR]}(Cl)}2(μ-Ph2P(CH2)nPPh2)], 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[η5-C5H2{C(H)O(CH2)3O}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[η5-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. Controlled acid hydrolysis of a dioxane ring yields either functionalized ferrocenylimine palladacycles with a non-coordinated formyl group, or an acetal derivative. [Display omitted] •Dinuclear and tetranuclear functionalized palladium(II)/ferrocene complexes with bridging diphosphines and monodentate phosphines.•Discussion of the hydrolysis procedure to induce the varied functionalized compounds.•First X-ray crystallographic study of a cyclopalladated ferrocenylimine bearing an acetal moiety.