Synthesis, Structure, and Coordination Properties of 1,1′-Bis(bis(trifluoromethyl)phosphino)ferrocene, dfmpf

Synthesis, transition metal chemistry and catalytic reactions of ferrocenylbis(phosphonite), [Fe{C5H4P(OC6H3(OMe-o)(C3H5-p))2}2]

The new metalloligand ferrocenylbis(phosphonite), [Fe(C5H4PR2)2 (R = OC6H3(OMe-o)(C3H5-p))], (2), is synthesized by the reaction of bis(dichlorophosphino)ferrocene Fe(C5H4PCl2)2 (1) with 4-allyl-2-methoxyphenol. The reactions of 2 with H2O2 and elemental sulfur or selenium afforded bischalcogenides, [Fe{C5H4P(E)(OC6H3(OMe-o)(C3H5-p))2}2] (3, E = O; 4, E = S; 5, E = Se), in good yield. The bis(phosphonite) reacts with group 6 metal carbonyls and group 10 metal dichloride precursors to produce the chelate complexes [{M(CO)4}Fe{C5H4P(OC6H3(OMe-o)(C3H5-p))2}2}] (6, M = Mo; 7, M = W) and [(MCl2)Fe{C5H4P(OC6H3(OMe-o)(C3H5-p))2}2] (8, M = Pd; 9, M = Pt). The palladium(ii) complex [(PdCl2)Fe{C5H4P(OC6H3(OMe-o)(C3H5-p))2}2] (8) is an efficient catalyst for the Suzuki-Miyaura cross-coupling reactions (TON up to 1.5 × 10(5)). The reaction of 2 with one equivalent of [RuCl2(η(6)-p-cymene)]2 yielded the binuclear complex [{Ru2Cl4(η(6)-p-cymene)2}Fe{C5H4P(OC6H3(OMe-o)(C3H5-p))2}2] (12) in good yield. Treatment of 2 with copper chloride in a 1 : 1 or 1 : 2 molar ratio resulted in the formation of a binuclear complex, [{(CuCl)Fe{C5H4P(OC6H3(OMe-o)(C3H5-p))2}2}2] (13), whereas a similar reaction of 2 with CuBr and CuI in a 1:2 or 1:2.5 molar ratio yielded the novel butterfly-like deca-nuclear complexes [Cu5(μ-X)5{Fe{C5H4P(OC6H3(OMe-o)(C3H5-p))2}2}2]2 (14, X = Br; 15, X = I). The reaction of 2 with two equivalents of [AuCl(SMe2)] afforded the digold complex [(AuCl)2Fe{C5H4P(OC6H3(OMe-o)(C3H5-p))2}2] (16), with the ligand exhibiting bridged-bidentate mode of coordination. Additionally, some complexes were studied by cyclic voltammetry. The crystal structures of complexes 8, 9, 12, 15 and 16 were determined using X-ray diffraction studies.

Diastereoselective synthesis and coordination chemistry of enantiopure keto-bis-(2-phosphametallocene)s

Enantiopure 2-(chlorocarbonyl)phosphametallocenes [MCp*(2-{COCl}-3,4-Me(2)-5-Ph-PC(4))] (M = Fe, Ru) react with phospholide anions to give 2-phosphametallocene-2'-acylphospholides K[MCp*(2-CO-2'-{3',4'-Me(2)-5'-PhPC(4)}-3,4-Me(2)-5-Ph-PC(4))] (M = Fe, Ru) and these have been converted into keto-bis-(2-phosphametallocene)s through reaction with [FeClCp*(tmeda)]; templation of this process with CuBr gives rise to the C(2)- (or pseudo-C(2)- when M = Ru) symmetric form of [{MCp*(3,4-Me(2)-5-Ph-PC(4))}(2)-2,2'-(CO)] (M = Fe, Ru; Fe, Fe) with high (>95%) diastereoselectivity. X-Ray structures of these ligands coordinated to [RuCp*Cl] and [PtCl(2)] centres show that the spatial orientation of the very flexible keto-bis-(2-phosphametallocene) structure is highly responsive to the coordination sphere of the chelated platinum or ruthenium centre.

Heterometallic platinum(II) compounds with β-aminoethylferrocenes: synthesis, electrochemical behaviour and anticancer activity

A new family of heterometallic compounds 3-6 containing ferrocenyl and platinum(II) centers has been synthesized by reaction of 1-β-aminoethylferrocene (1) and 1,1'-bis(β-aminoethyl)ferrocene (2) with Pt(II) precursors. Using K(2)[PtCl(4)] as the Pt(II) source, the cis-square-planar neutral compounds [Fe{η(5)-C(5)H(4)(CH(2))(2)NH(2)}(2)PtCl(2)] (3) and [{Fe(η(5)-C(5)H(4)(CH(2))(2)NH(2))(η(5)-C(5)H(5))}(2)PtCl(2)] (5) were obtained. Reaction of cis-[PtCl(2)(dmso)(2)] with 1 and 2 resulted in the displacement of dmso and chloride ligands from the platinum coordination sphere, affording the cationic and neutral compounds [Fe{η(5)-C(5)H(4)(CH(2))(2)NH(2)}(2)Pt(dmso)Cl]Cl (4) and [Fe(η(5)-C(5)H(4)(CH(2))(2)NH(2))(η(5)-C(5)H(5))Pt(dmso)Cl(2)] (6). Compounds 3-6 were thoroughly characterized using multinuclear ((1)H, (13)C, (195)Pt) NMR, IR spectroscopy, ESI mass spectrometry and elemental analysis. Single-crystal X-ray analysis of heterometallic 6 confirmed the cis geometry of the molecule and revealed that the platinum atom is held in a perfect square-planar geometry. The electrochemical behaviour of the heterometallic compounds 3-6, which has been examined by cyclic (CV) and square wave (SWV) voltammetries in dichloromethane and dmso solution, is characterized by the reversible one-electron oxidation of the ferrocene moieties. The results of the biological activity studies revealed that the organometallic complex 5 is active against all cell lines with GI(50) values in the range 1.7-2.3 μM. When compared to the standard anticancer drug cisplatin, heterotrimetallic 5, possessing two aminoethylferrocenyl units coordinated to the Pt(II) center, showed a greater activity profile in the colon cancer cell line. Cell cycle studies revealed that the new mixed compound exhibits a mechanism of action different to cisplatin.