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rac-2-[(Diphenylphosphino)methyl]ferrocenecarboxylic acid (1) was prepared in a good yield from rac-2-(N,N-dimethylaminomethyl)bromoferrocene (2) via rac-2-(hydroxymethyl)bromoferrocene (4) and rac-2-[(diphenylphosphino)methyl]bromoferrocene (5), and further converted to the respective phosphine oxide (6), phosphine sulfide (7) and methyl ester (8). The phosphines 1 and 8 were studied as ligands in rhodium complexes. The reaction of di-μ-chloro-bis[chloro-(η5-pentamethylcyclopentadienyl)rhodium(III)] with the stoichiometric amounts of 1 and 8 yielded the corresponding mononuclear complexes with P-monodentate ligands: [RhC2(η5-C5Me5)(L-κP)], 9 and 10, respectively. Attempted deprotonation of 9 with LiBu or KOt-Bu gave intractable mixtures, in which the parent complex 9 as the major component was accompanied by two new compounds, likely the diastereoizomeric phosphinocarboxylate complexes. A defined O,P-chelating phosphinocarboxylate complex, [SP-4-2]-carbonyl-[rac-2-{(diphenylphosphino)methyl}ferrocenecarboxylato-κ2O,P]-tricyclohexylphosphinerhodium(I) (12), was obtained from the displacement of acetylacetonate(1−) (acac) ligand in [Rh(acac)(CO)(PCy3)] (Cy = cyclohexyl) with acid 1. The structures of 1, 6 · CHCl3, and 7 · 1/2 CH2Cl2, 10, and hydrated complexes 9 and 12 were determined by single-crystal X-ray diffraction.

The ortho-palladated dimer trans-[{Pd(μ-Cl)(C6H4CHNMe2-κ2C1,P)}2] (1) reacts with methyl 1′-(diphenylphosphino)ferrocenecarboxylate (2) under bridge cleavage to afford [SP-4-4]-[PdCl(C6H4CH2NMe2-κ2C1,P){Fe(η5-C5H4PPh2-κP)(η5-C5H4CO2Me)}] (3) while a reaction between the cationic complexes [Pd(C6H4CHNMe2-κ2C1,P)(MeCN)2]X (4, X = ClO4 (a) and BF4 (b)) with 2 gives the products of replacement of one acetonitrile ligand trans to nitrogen, [SP-4-3]-[Pd(C6H4CHNMe2- κ2C1,P){Fe(η5-C5H4PPh2-κP(η5-C5H4CO2Me)}(MeCN)]X (5a, 5b). The crystal structures of 4a and 5a have been determined by X-ray crystallography. Compounds 3, 5b and other in situ generated complexes with the related ferrocene phosphines were tested as catalysts in Suzuki–Miyaura coupling of 4-bromotoluene and phenylboronic acid.

Deprotonation of racemic [2-(diphenylphosphino)ferrocenyl]acetonitrile (1) with NaN(SiMe3)2 in THF followed by reaction with electrophiles MeI and Ph2PCl affords the substituted nitriles, 2-[2-(diphenylphosphino)ferrocenyl]propionitrile (2a) and 2-(diphenylphosphino)-[2-(diphenylphosphino)ferrocenyl]acetonitrile (2b), respectively. Whereas the former reaction yields a 15:1 mixture of isomers differing in configuration at the alkylated α-carbon from which the major diastereoisomer can be isolated by simple recrystallization, the latter gives 2b as a single diastereoisomer. The dominating product of the methylation reaction was characterized by X-ray diffraction analysis as (S,Rp/R,Sp)-2a, which is in accordance with the possible access of the electrophile towards deprotonated 1.

Amide coupling of (Sp)-2-(diphenylphosphanyl)ferrocene-1-carboxylic acid with appropriate terminal amines mediated by 1-hydroxybenzotriazole and a carbodiimide affords multi-donor amides terminally functionalized with planar-chiral (Sp)-2-(diphenylphosphanyl)ferrocen-1-yl moieties in good to excellent yields. Palladium catalysts based on these ligands efficiently promote asymmetric allylic alkylation of 1,3-diphenylallyl acetate with in situ generated dimethyl malonate anion to give the C-alkylated product with ees up to 93% at room temperature. Copyright © 2010 John Wiley & Sons, Ltd.

The title compound, [Ti(C(10)H(15))(C(20)H(26)Si)], was obtained from the reaction of [Ti{η(5):η(1)-C(5)Me(4)(CH(2))}(η(5)-C(5)Me(5))] with the alkynylsilane PhC(2)SiMe(2)H. The complex crystallizes with two independent mol-ecules in the asymmetric unit, which differ in the conformation of the propenyl unit, resulting in their having opposite helicity. No inter-molecular inter-actions or inter-actions involving the Si-H bond are present. The observed geometrical parameters are unexceptional compared to known structures of the same type.

A series of supported catalysts is prepared by treatment of SBA-15-type mesoporous molecular sieve bearing [triple chemical bond]SiCH(2)CH(2)CH(2)NHCH(2)CH(2)NEt(2) groups with palladium(II) acetate. These catalysts are studied in Suzuki biaryl couplings and in Heck reactions to establish the influence of metal loading and innocent surface modifications (trimethylsilylation). The Suzuki reaction proceeded efficiently with model and practically relevant substrates; the catalyst performance increasing with an increasing degree of metalation (decreasing N/Pd ratio). Catalyst poisoning tests revealed that the reaction takes place in the liquid phase with the catalyst serving as a reservoir of active metal species and also as a stabilizing support once the reaction is performed. In the Heck reactions, on the other hand, the catalyst performance strongly changed with the reaction temperature and with the N/Pd ratio. The material with the lowest metal loading (0.01 mmol palladium per gram of material, N/Pd ratio ca. 100:1) proved particularly attractive in the Heck coupling, being highly active at elevated temperatures, recyclable, and capable of acting as a bifunctional catalyst (i.e., functioning without any external base.

The isomeric ferrocene phosphine-carboxamides, 1-(diphenylphosphino)-1'-{[N-(2-pyridyl)-methyl]carbamoyl}ferrocene (1) and 1-(diphenylphosphino)-1'-{[N-(4-pyridyl)methyl]carbamoyl}ferrocene (2) have been studied as ligands in group-12 metal bromide complexes. The reactions of 1 with CdBr2 x 4H2O and HgBr(2) at 1:1 mole ratio gave the discrete tetracadmium complex [Cd2(micro-Br)2(-1kappa2O,N2)2[micro-1kappa2O,N2:2kappaP-(C5H4N)CH2NHC(O)fcPPh2-CdBr3]2] (7; fc = ferrocene-1,1'-diyl) and the halogeno-bridged dimer [[Hg(micro-Br)Br(-kappaP)]2] (8), respectively. In the presence of acetic acid, the CdBr2-1 system furnished a zwitterionic complex featuring protonated 1 as the P-monodentate donor, [CdBr3[Ph2PfcC(O)NHCH2(C5H4NH)-kappaP]] x H2O (6 x H2O). Under neutral conditions, compound , whose terminal donor groups are better arranged for the formation of extended assemblies, gave rise to one-dimensional coordination polymers [MBr2[micro(P,N)-]](n) (M = Cd, 4; M = Hg, ). The crystal structures of 2 x H2O, its corresponding phosphine oxide (3 x H2O), and complexes 4, 5, 6 x H2O, and have been determined, revealing extensive hydrogen bonding interactions in the solid state.

Neutral [Pd(?P,?O-P~O)(?3C,C,C-carbocycloenyl)] complexes, where P~O is a chiral or achiral chelating phosphanylferrocenecarboxylate ligand, were synthesized and characterized by multinuclear NMR spectroscopy. The crystal structure of a representative complex was determined by single- crystal X-ray diffraction analysis. In all complexes, the palladium(II) ion is located at the centre of a square plane formed by the P and O donor atoms from an anionic P~O- ligand, a ?-carbon atom and a C-C double bond from a carbocycloenyl ligand. Neutral methyl complexes with the formulas [PdCl(Me)(?P,?H-P~OH)] and [Pd(Me)(OTs)(?P,?HP~ OH)] were also synthesized and characterized. On the basis of IR, NMR and MS-FAB data, the methyl complexes are proposed to be formulated with the fourth coordination position occupied by an agostic O-H···Pd interaction from a free carboxylic acid moiety [P~OH = 1-(diphenylphosphanyl)ferrocenecarboxylic acid] or a solvent molecule. Selected complexes were employed as catalyst precursors for CO-ethyl- Introduction The organometallic chemistry of functionalized phosphanes modified with an additional (non-phosphane) donor group is attracting considerable attention, predominantly because of its successful and varied applications in homogeneous catalysis.[1] As a contribution to this area, some of us have designed and synthesized several phoshanylferrocenecarboxylic acid ligands (Scheme 1) and studied their ability to coordinate to transition metals, with the ultimate goal of utilizing the obtained compounds in cataly- [a] Istituto di Chimica dei Composti Organometallici (ICCOMCNR), Area di Ricerca CNR di Firenze, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy Fax: +39-0555-225-203 E-mail: werner.oberhauser@iccom.cnr.it [b] ICCOM-CNR, Sezione di Pisa, c/o Dipartimento di Chimica e Chimica Industriale, Via Risorgimento 35, 56126 Pisa, Italy [c] Charles University in Prague, Faculty of Science, Department of Inorganic Chemistry, Hlavova 2030, 12840 Prague, Czech Republic Fax: +420-221951253 E-mail: stepnic@natur.cuni.cz Eur. J. Inorg. Chem. 2008, 441-452 © 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 441 ene copolymerization in MeOH in the presence of an excess of p-toluenesulfonic acid. In all cases, low molecular weight semialternating polyketones were produced. The catalytic activities were rather low and the extra-ethylene insertion reached a maximum value of 4.3%. An operando high-pressure NMR experiment with [Pd(Me)(S)2(?P-P~OH)]OTs (S = solvent, adventitious water) precursor showed that this monocationic PdII alkyl complex is readily converted into a catalytically inactive binuclear carbonyl-bridged PdI compound, which, however, regenerates catalytically active PdII- H species by reaction with TsOH and that ?-chelates of the formula [Pd(CH2CH2C(O)P)(S)(?P-P~OH)]OTs (P = propagating polyketone chain) are catalyst resting states. For the first time, ?-chelate propagating species have been intercepted in a CO-olefin copolymerization assisted by catalysts devoid of a chelating ligand.

The title compound, [Fe(C(5)H(5))(C(30)H(32)O(7)P)], which is an inter-mediate in the synthesis of (R(p))-2-(diphenyl-phos-phino)ferrocene-1-carboxylic acid, crystallizes in the common chiral space group P2(1)2(1)2(1). In general, the mol-ecular geometry is very similar to that of the corresponding 2,1'-bis-(diphenyl-phosphino) congener. The ferrocene unit assumes a regular geometry with the proximal bulky substituents efficiently avoiding mutual spatial contacts. In the crystal, the mol-ecules participate in weak intra- and inter-molecular C-H⋯O inter-actions.

Functional group transformations at the group 4 metallocene framework have been demonstrated, which have provided relatively straightforward access to otherwise synthetically challenging derivatives. The pendant nitrile group in Ti and Zr metallocene complexes of the type [(η(5)-C5Me5)(η(5)-C5H4CMe2CH2CN)MCl2] was converted into an intramolecularly bound ketimido moiety by alkylation, which took place not only at the nitrile, but also at the metal centre. The choice of an alkylating reagent (alkyl/aryl lithium, Grignard reagent) was crucial: e.g., 2 equiv. of MeMgBr effected the alkylation only at the metal, yielding selectively complexes [(η(5)-C5Me5)(η(5)-C5H4CMe2CH2CN)MMe2], while the use of PhMgBr, PhLi, or MeLi instead gave selectively the ketimido complexes. Organyl lithium reagents were, however, not compatible with the titanocene derivatives. The metal-bound ketimides were subsequently cleaved off by the reaction with HCl, which afforded metallocene dichlorides with a pendant imino group. These compounds were easily protonated again at the nitrogen atom to produce a cationic iminium moiety. Aqueous hydrolysis of the imine or its respective hydrochloride proved to be viable in the case of Zr and it finally afforded a pendant ketone group attached to the zirconocene framework.

The title compound, [Ti(C10H15)(C20H26Si)], was obtained from the reaction of [Ti{η5:η1-C5Me4(CH2)}(η5-C5Me5)] with the alkynylsilane PhC2SiMe2H. The complex crystallizes with two independent mol­ecules in the asymmetric unit, which differ in the conformation of the propenyl unit, resulting in their having opposite helicity. No inter­molecular inter­actions or inter­actions involving the Si—H bond are present. The observed geometrical parameters are unexceptional compared to known structures of the same type.

A novel polar dppf derivative possessing only planar chirality, 1′,2-bis(diphenylphosphino)-ferrocene-1-carboxylic acid (Hdpc), has been synthesised in racemic form and resolved into enantiomers via esters with D-glucose diacetonide ((Rp)- and (Sp)-3). (Rp)-Hdpc was further converted to a series of N-substituted amides that were studied as ligands for Pd-catalysed enantioselective allylic alkylation of racemic (E)-1,3-diphenylprop-2-en-1-yl acetate or ethyl carbonate with malonate esters, showing high activity and good enantioselectivity (er up to 10 : 90). The catalytic results were correlated with the structural data (X-ray diffraction and solution NMR) for (η3-allyl)palladium(II) complex (Rp)-[Pd(η3-1,3-Ph2C3H3){Fe(η5-C5H3-1-(C(O)NHCH2Ph)-2-(PPh2-κP))(η5-C5H4PPh2-κP)}]ClO4 (16) as a model of the plausible reaction intermediate. A further study into the coordination properties of Hdpc led to isolation of chelate complex [PdCl2(Hdpc-κ2P,P′)] (12). The crystal structures of rac-Hdpc, methyl ester of (Rp)-Hdpc, glycoside (Rp)-3, and 12·Me2CO suggested a close structural relationship between dppf and Hdpc.