Synthesis of Two Isomeric Ferrocene Phosphanylcarboxylic Acids and their PdII Complexes with and without Auxiliary ortho-Metalated C,E-Ligands (E = N and S).

Two homologous ferrocene phosphanylcarboxylic acids, viz., 1'-[(diphenylphosphanyl)methyl]ferrocene-1-carboxylic acid (HL1) and [1'-(diphenylphosphanyl)ferrocenyl]acetic acid (HL2), were synthesized and studied as ligands in PdII complexes. The addition of these hybrid donors to [PdCL2(MeCN)2] led to the bis-phosphane complexes trans-[PdCL2(HL1-κP)2] and trans-[PdCL2(HL2-κP)2]. In contrast, the reactions of HL1 and HL2 with the PdII acetylacetonate (acac) complexes [(LYC)Pd(acac)], where LYC = 2-[(dimethylamino-κN)methyl]phenyl-κC1 (LNC) and 2-[(methylthio-κS)methyl]phenyl-κC1 (LSC), proceeded under proton transfer and replacement of the acac ligand, giving rise to O,P-bridged phosphanylcarboxylate dimers [LYCPd(μ(P,O)- L1)]2 and molecular chelates [LYCPd(L2-κ2O,P)]2, respectively. The analogous reactions involving 1'-(diphenylphosphanyl)-1-ferrocenecarboxylic acid (Hdpf) provided the macrocyclic tetramer [LNCPd(μ(P,O)-dpf)]4 and the dimer [LSCPd(μ(P,O)-dpf)]2. The reactions of HL1 with [Pd(acac)2] only led to an ill-defined, insoluble material, whereas those with HL2 produced a separable mixture of the bis-chelate complexes trans-[Pd(L2-κ2O,P)2], cis- [Pd(L2-κ2O,P)2], and [Pd(acac)(L2-κ2O,P)]. [ABSTRACT FROM AUTHOR]