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Quality characteristics of olive products significantly depend on cultivar (cv), among other factors. In this study, seven traditional, noncommercial Greek cultivars, along with the commercial Spanish Arbequina cv., were examined for the phenolic antioxidant dynamic of their leaves. Polar extracts (aqueous, methanol, and ethanol) were analyzed for Total Phenol (TP), Flavonoid (TFL), Hydroxycinnamic Acid Derivatives (THAD), Flavonol (TFLVN) contents, DPPH radical scavenging ability, and Ferric Reducing Capacity (FRAP). Selective characteristics of olive leaf methanol extracts for all cultivars were re-examined on a second sampling period. Olive leaf is considered a rich source of phenolic antioxidants total phenol content reaching 29.3 &plusmn, 1.3, 30.6 &plusmn, 0.4, and 27.0 &plusmn, 1.1 mg caffeic acid/g dry leaf for aqueous, methanol, and ethanol extracts, respectively) and all cultivars were considered of equal bioactive dynamic. TP data derived from Folin&ndash, Ciocalteu and another spectrophotometric assay employed presented a high correlation for all examined cases (R2 = 71.5&ndash, 86.9%). High correlation (R2 = 0.92) was also found between TP and FRAP findings of aqueous extracts. Olive leaf is considered a promising source of phenolic antioxidants irrelevant to cultivar and therefore even cultivars less effective for oil or table olive production could be efficiently exploited for the bioactive dynamic of their leaves.

A systematic study of the cellular uptake of emissive complexes as a function of their lipophilicity is presented. Here a series of amphiphilic rhenium fac-tricarbonyl bisimine complexes bearing axial substituted imidazole or thiazole ligands, [Re(bpy)(CO)3(ImCnHm)]+ {n = 1 m = 3 (1+), n = 4 m = 9 (2+), n = 8 m = 17 (3+), n = 12 m = 25 (4+), n = 16 m = 33 (5+), n = 2 m = 3 (6+); bpy = 2,2'-bipyridine, Im = imidazole} and [Re(bpy)(CO)3(L)]+ {L = 1-mesitylimidazole, ImMes (7+), 4,5-dimethylthiazole, dmt (8+) and 4-methyl-5-thiazole-ethanol, mte (9+)} is reported. The X-ray crystal structures of 2+, 8+ and 9+ confirm the geometry and expected distribution of ligands and indicated that the plane of the imidazole/thiazole ring is approximately parallel to the long axis of the bipy ligand. Luminescence studies revealed excellent properties for their use in cell imaging with visible excitation and broad emission profiles. Their uptake in two distinct species has been examined by fluorescence imaging of the diplomonad fish parasite Spironucleus vortens (S. vortens) and rod-shaped yeast Schizosaccharomyces pombe (Schiz. pombe) as a function of their lipophilicity. The uptake of the complexes was highest for the more lipophilic 2+-5+ in both S. vortens and Schiz. pombe in which the long alkyl chain aids in crossing bilipid membranes. However, the increased lipophilicity of longer chains also resulted in greater toxicity. Localisation over the whole cell varied with differing alkyl chain lengths with complex 2+ preferentially locating to the nucleus of S. vortens, 3+ showing enhanced nuclear partitioning in Schiz. pombe, and 4+ for the remaining cell wall bound in the case of S. vortens. Interestingly, complexes of intermediate lipophilicity such as 7+ and 8+ showed reasonable uptake, proved to be non-toxic, and were capable of crossing exterior cell walls and localising in the organelles of the cells.

Cationic Ir(III) systems supported by a bis(expanded NHC) framework and featuring both agostic C-H and cis alkyl/hydride ligand sets have been targeted by protonation of the corresponding bis(alkyl) hydride complexes. Remarkably, the steric shielding afforded by the NHC substituents is such that these and related putative 14-electron cations are air and moisture stable. In solution, degenerate fluxional exchange is brought about by reversible σ-bond activation within the agostic alkyl C(sp3)-H bond; a non-dissociative mechanism is implied by the activation parameters ΔH‡ = 8.8(0.4) kcal mol-1 and ΔS‡ = -12.2(1.7) eu. © 2012 American Chemical Society.

The synthesis and silver(I) and gold(I) coordination chemistry of a new chiral, bidentate N-heterocyclic carbene (NHC) dehydrohexitol derivative (3) are reported. The imidazolium salt [H23][PF6]2 reacts with Ag2O and Au(tht)Cl (tht = tetrahydrothiophene) precursors to form the isostructural 18-membered metallamacrocyclic dimers [Ag2(μ-3)2][PF6]2 and [Au2(μ-3)2][PF6]2 and the monocarbene complex [(AuCl)2(μ-3)]. Single-crystal X-ray structures have been determined for the bis-imidazolium precursor [H23][PF6]2 and corresponding Ag(I) and Au(I) complexes of ligand 3. Comparison between the X-ray-derived structures and solution-phase NMR data for [Ag2(μ-3)2][PF6]2 and [Au2(μ-3)2]- [PF6]2 demonstrate that the complexes adopt a conformation in solution different from that found in the solid state, implying a conformational flexibility of the metallamacrocycle in solution. Both [(AuCl)2(μ-3)] and [Au2(μ-3)2][PF6]2 are emissive in the solid state at ca. 380 nm (λex = 295 nm). Time-resolved luminescence measurements indicate different excited-state lifetimes for the two species, with [(AuCl)2(μ-3)] measured at 35 ns and [Au2(μ-3)2][PF6]2 at 379 ns. The chiroptical properties of the silver and goldNHCcomplexes have been studied by circular dichroism (CD).

The performances of a number of RhI and IrI complexes of type [M(NHC)(COD)Cl] in the transfer hydrogenation of ketones were tested under a variety of reaction conditions, and with a variety of substrates, allowing comparison of Rh- and Ir-NHC complexes, and also comparison of the influence of the NHC ligand on catalytic performance. Notably, of the RhI and IrI complexes with symmetrically substituted NHCs only those bearing cyclohexyl substituents were active, with RhI complexes of saturated 5-, 6- and 7-NHCs with N-Mes substituents, [Rh(5,6,7-Mes)(COD)Cl], showing no activity in transfer hydrogenation under the test conditions. RhI and IrI complexes of unsymmetrical o-methoxyphenyl donor-functionalised NHCs (df-NHC) with differing carbene ring sizes were also tested in transfer hydrogenations, with the RhI complexes displaying no catalytic activity. However, the corresponding df-NHC IrI complexes were found to be extremely effective catalysts. Catalyst tests also demonstrated the excellent stability of these complexes.

An unsaturated seven-membered amidinium salt 7 decomposes in the presence of metal salts under basic conditions. However, 7 readily forms a Diels–Alder cycloadduct with CpH from which the RhI complexes may be prepared. Thus, structurally elaborate, sterically crowded carbene ligand complexes bearing peripheral unsaturated functionality are available in a short versatile synthesis.

The rhodium complexes [Rh(NHC)(COD)Cl] and cis-[Rh(NHC)(CO)2Cl] of seven-membered N-heterocyclic carbenes (NHC) bearing aromatic N-substituents (mesityl, xylyl and o-tolyl) were synthesised, and a comparison of their steric and electronic properties with those of the analogous five- and six-membered NHC complexes was made on the basis of infrared and solid-state data. The X-ray structures for the complexes Rh(6-Mes)(COD)Cl, Rh(7-Mes)(COD)Cl and Rh(7-oTol)(COD)Cl were determined.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

The addition of aromatic formamidines to dihaloalkanes proceeds in air under mildly basic conditions and in polar solvents to afford the corresponding amidinium salts in high yields. To demonstrate the wide scope of this methodology, several five-, six-, and seven-membered saturated N-heterocyclic amidinium salts have been prepared. The free carbenes 7-Mes, 7-Xyl, 7-Pri, 6-Mes, and 6-Xyl have also been isolated as stable white solids, and for the first time the solid state structures of free seven-membered N-heterocyclic carbenes have been determined (7-Mes and 7-Xyl). The syntheses and characterization of their Ag(I) halide complexes are also described and the X-ray structures for Ag(6-Pri)Br, Ag(7-Mes)Br, Ag(7-Xyl)I, and Ag(Xyl7-Mes)Br determined. On the basis of NMR data the silver halide species form either neutral, Ag(NHC)X, or ionic, [Ag(NHC)2][AgX2] complexes in solution. A feature of the expanded ring carbenes is the extremely large NCN angle (≥120°) and the consequential steric impact of the N-substituents on the metal center. For the free seven-membered ring carbenes the 13C NMR shifts are 258−260 ppm, well down field from those observed for the six- and five-membered ring carbenes.

The synthesis of the novel seven-membered N-heterocyclic carbene (NHC) 1,3-dicyclohexyl-1,3-diazepan-2-ylidene (3) and its 5,6-dioxolane derivative 4 is reported and their coordination chemistry with Rh(I), Ir(I), and Pt(0) discussed. The M(cod)(3)Cl, where M = Rh and Ir, complexes display a high rotation barrier at room temperature about the M−CNHC bond, whereas for the M(CO)2(3)Cl and Pt(nbe)2(3) complexes rapid rotation of the carbene ligand is observed at ambient temperature. The infrared ν(CO) values of the Rh(I) and Ir(I) derivatives M(CO)2(3)Cl give a measure of the donor ability of the new carbene ligands. The crystal structures of the amidinium salts 3·HPF6 and 4·HPF6 together with those of M(cod)(3)Cl [M = Rh, Ir], Ir(cod)(4)Br, Ir(CO)2(3)Cl, and Pt(nbe)2(3) are reported. Both the salts and the coordinated carbene ligands exhibit extremely large NCN angles; for the complexes the angles are in the range 115.5(3)° [Pt(3)] to 122(11)° [Ir(4)].

Complexes of the type [Ir(ddppm)(COD)]X were prepared and tested in the asymmetric hydrogenation of a range of imine substrates. Contrary to known iridium catalysts, the ddppm complexes formed efficient catalysts under an atmospheric hydrogen pressure, whereas at higher pressures the catalytic activity of the system was drastically reduced. Depending upon the reaction conditions, N-arylimines, Ar′NCMeAr, were hydrogenated to the corresponding secondary amines in high yields and enantioselectivities (80–94% ee). In contrast to the [BF4]− and [PF6]− complexes, coordinating anions such as chloride did not form active Ir-ddppm hydrogenation catalysts. The cationic Ir-ddppm hydrogenation system performed well in chlorinated solvents, whereas coordinating solvents deactivated the system. Dimeric and trimeric Ir(III) polyhydride complexes were formed from the reaction of [Ir(ddppm)(COD)]PF6 with molecular hydrogen at atmospheric pressure and were found to inhibit catalytic activity.

The chiral P,S ligand 1-(diphenylphosphino)butane-2-thiol, L1H, and its thioether methyl derivative L1Me have been synthesized. L1H reacts with divalent Ni, Pd and Pt salts to form phosphinothiolato complexes of general formula [M(L1)Cl]2 (1, M = Ni), (2, M = Pd), M(L1)2 (3, M = Ni), (4, M = Pd), (5, M = Pt) and M(L1)(PR3)X, (6, M = Pd, R = Ph, X = Cl), (7, M = Pd, R = nBu, X = Cl), (8, M = Pt, R = Ph, X = H). Single crystal X-ray crystallography reveals a ‘butterfly’ shape for the dimeric structures of nickel and palladium complexes, 1 and 2 respectively. The P,S chelate ring, according to solid state structural data and NMR analysis, adopts a preferred δ skew-conformation for the S isomer and a λ conformation for the R isomer. Complex 6 dissociates in chloroform solutions to form the dimeric species 2 and free PPh3. Thermodynamic parameters for this process have been calculated.

High hydrostatic pressure-treated strawberry jam samples were examined with respect to their textural and colour properties, the aim being to establish the relationship between pectin concentration, texture and colour. Samples were prepared with varying amounts of pectin (0.1, 0.5, 2.5, 5, 7.5 and 10% w/w) and were processed using the same parameters (400 MPa, for 5 min at 25°C). After preparation, the samples were rheologically tested using a cone and plate configuration on a Creep Viscometry Oscillation rheometer. A colour spectrophotometer was used to monitor (at 505 nm) the changes in colour during storage. Comparing these experimental samples with commercially available samples of high pressure and traditional strawberry jams, it was found that the best texture was achieved when the pectin concentration was between 2.5 and 5% w/w. With increasing pectin concentration, the storage and loss moduli (indicators of liquid- and solid-like characteristics) were increased. Colour was found to be affected by the increasing pectin concentration, as the absorbance intensity was decreased, suggesting a relation between pectin and anthocyanin degradation.

The zerovalent complexes Pd(Ph2Ppy)31 and Pd(Ph2Ppy)2(dba) 2, where Ph2Ppy is diphenyl-2-pyridylphosphine and dba = trans,trans-dibenzylideneacetone, have been synthesized and characterised. Reactions of 1 with alkynes have been studied and the dimethyl acetylenedicarboxylate complex Pd(Ph2Ppy)2(η2-DMAD) 3, where DMAD is dimethyl acetylenedicarboxylate, isolated and structurally characterised. The complexes trans-Pd(Ph2Ppy)2(PhC[double bond, length half m-dash]CH2)X, X = CF3CO2−4 or Cl−5, and trans-Pd(Ph2Ppy)2{CO(CH3)C[double bond, length half m-dash]CH2}Cl 6 result from oxidative addition of phenylacetylene/CF3CO2H, phenylacetylene/Et3NHCl and methacryloyl chloride respectively to 1, and the crystal structure of 4 is presented. The alkenyl ligand is bound to palladium through the α carbon in 4. Insertions into the M–C bond of the vinyl complexes have been studied. No isolable insertion product is obtained with carbon monoxide although the complex is active for the catalytic alkoxycarbonylation of phenylacetylene to 2-phenylpropenoate. Propadiene inserts into the Pd–C bond in 4 to give the cationic π-allyl complex [Pd(Ph2Ppy)2{η3-C3H4C(Ph)[double bond, length half m-dash]CH2}][CF3CO2] 7. The complex Pd(Ph2Ppy)3 is found to catalyse the vinylation of Ph2Ppy to the corresponding 2-propenylphosphonium trifluoromethanesulfonate.

The alkoxycarbonyl complexes Pd(Ph2Ppy)2(CO2R)(OAc) where Ph2Ppy is 2-pyridyldiphenylphosphine and R = Me 1, Et 2, i-Pr 3 have been prepared from Pd(OAc)2 and Ph2Ppy in ethanol solution under an atmosphere of CO. Increasing the CO pressure favours the formation of palladium carbonyl species. In the presence of 2 mol equivalents of CF3CO2H, the complex Pd(Ph2Ppy)2(CO2CH3)(CF3CO2) 4 is isolated from methanol. Pd(Ph2Ppy)2(CO2CH3)Cl 5 has been obtained by the reaction of Pd(Ph2Ppy)2Cl2 with NaOCH3 in the presence of CO. 1 and 5 have been crystallographicaly characterised as trans isomers, a geometry confirmed for all the complexes by 13C NMR. The reactivity of the complexes toward alkynes and propadiene has been investigated and the π-allyl complex [Pd(Ph2Ppy)2{η3-C3H4C(CH3)[double bond, length half m-dash]CH2}][O2CCF3] 8 isolated and structurally characterised.

The stoichiometric reaction of diphenyl-2-pyridylphosphine (Ph2PC5H4N-2) and palladium(II) acetate afforded the palladium(I) dimer [Pd2(µ-Ph2PC5H4N)2(OAc)2] 1. Attempts to isolate the monomer, [Pd(µ-Ph2PC5H4N)2(OAc)2], from 2∶1 stoichiometry reactions (Ph2PC5H4N∶Pd), resulted only in the isolation of 1. When >3 mole equivalents of Ph2PC5H4N were used the zerovalent palladium complex [Pd(Ph2PC5H4N)3] was isolated. Other palladium(I) dimers with carboxylic or sulfonic anionic ligands have been prepared by a metathesis reaction of the co-ordinated acetates. The complexes 1 and [Pd2(µ-Ph2PC5H4N)2(O2CCF3)2] 2 have been structurally characterised as head-to-tail dimers. The mononuclear complex [Pd(Ph2PC5H4N)2(O2CCF3)2] has been obtained by reaction of Ph2C5H4N with [Pd(CH3CN)2(O2CCF3)2]. Complex 1 reacts with dimethyl acetylenedicarboxylate to give [Pd2(µ-Ph2PC5H4N)2(OAc)2(µ-MeO2CCCCO2Me)], while attempts to isolate an A-frame carbonyl complex were unsuccessful.

This report summarizes the literature from 2009 relevant to the chemistry of the group 10 transition elements. Novel coordination and organometallic compounds of these elements are presented and selected applications in the areas of catalysis, bioinorganic/medicinal chemistry are discussed.

Convenient syntheses of mono- and bis-imidazolium 1,3,5-triazine derivatives bearing piperidine and morpholine substituents are reported. In situ deprotonation of the mono-imidazolium salts and reaction with Ag2O or Au(tht)Cl (tht = tetrahydrothiophene) precursors affords the corresponding Ag(NHC)Cl and Au(NHC)Cl carbene complexes. In the presence of Ag(I) or Au(I) salts the bis-imidazolium pincers eliminate the imidazolium group to afford -OMe or -NMe2 substituted triazines depending on the solvent used. In solution, the Ag(I) and Au(I) complexes show a barrier to rotation about the Ctriazine-Namine bonds, with calculated ΔG(≠) barriers in the region of 70 kJ mol(-1). Single crystal X-ray structures of several of the proligands and their corresponding Ag(I) and Au(I) complexes were obtained. These universally reveal an extended, rigidly planar π-conjugated network between the triazine core, imidazolium/imidazolylidene substituents and exocyclic amine functions, to which the origin of the rotational barrier observed in solution is attributed. Only very weak Ntriazine-metal interactions are observed in the solid state, as indicated by small deviations of the CNHC-Ag-Cl bond angles from 180° and also supported by DFT calculations on the Ag(NHC)Cl complex (NHC = 4,6-dipiperidinyl-2-methylimidazolylidene triazine). Preliminary antimicrobial susceptibility studies against five microorganisms (methicillin resistant Staphylococcus aureus NCTC 13277, S. aureus NCTC 6571, Pseudomonas aeruginosa NCTC 10662, Proteus mirabilis NCTC 11938 and Candida albicans ATCC 90028) show that the above triazine-based Ag-NHC complexes are active antimicrobial and antifungal agents.

The reaction of diamino-ligated dimethylpalladium(I1) complexes [Pd(Me)z(N-N)] (N-N = tmeda, bpy) with an equimolar amount of 1,1,1,3,3,3-hexafluoro-2-propanol r (substituted) phenols affords the new complexes [Pd(Me)(OR)(N-N)] (N-N = tmeda, R = CH(CF3)z (l), C6H5 (3), CsH4-4-NOz (4), CsH4-2-OH (11)); N-N = bpy, R = CH(CF3)2 (2)). These methylpalladium(I1) alkoxides and aryloxides are isolated in high yields as yelloworange solids and are remarkably thermally stable. Monoor bidentate ligands can substitute the tmeda ligand in 1 to afford a variety of methylpalladium alkoxide complexes [Pd(Me)(OCH(CF3)z)L2] (Lz = bpy (2), Ph2PCHzCH2NMez (12), dppe (13), 2PMe3 (14)). Crystals of 1,3, and 4 have been subjected to X-ray diffraction studies. Crystals of 1 are monoclinic, space group P2l/c, with unit-cell dimensions a = 8.2054(5) A, b = 17.2310(9) A, c = 11.1191(12) A, P = 105.701(7)", and Z = 4. Crystals of 3 are orthorhombic, space group Pbca, with unit-cell dimensions a = 10.572(2) A, b = 16.446(2) A, c = 17.029(3) A, and Z = 8. Crystals of 4 are orthorhombic, space group Pbca, with unit-cell dimensions a = 11.918(5) A, b = 12.089(3) A, c = 22.684(7) A, and Z = 8. The molecular structures of these complexes show them to be square-planar species, and in 1 the Cp-H unit of the fluorinated alkoxide is directed toward the palladium center (H-..Pd = 2.89(3) A), in what can be interpreted as the incipient stage of a P-hydrogen elimination. The palladium alkoxide or aryloxide complexes 1-4 when treated with 1 equiv of the corresponding alcohol or (substituted) phenol afford O-H-**O hydrogen-bonded adducts [Pd(Me)(OR)(N-N)]-HOR (N-N = tmeda, R = CH(CF3)2 (5) , C6H5 (7), C&-4-N02 (8); N-N = bpy, R = CH(CF3)z (6), C6H5 (9)). The X-ray molecular structures of [Pd(Me)(OC6H5)(tmeda)].HOCsHs (7) and [Pd(Me)(oCsH4-4-N02)(tmeda)]*HOC6H4-4-Noz (8) reveal that the aromatic alcohol is associated with the oxygen atom of the aryloxide through 0-H-0 hydrogen bonding. Crystals of 7 are monoclinic, space group P21/c, with unit-cell dimensions a = 15.5556(13) A, b = 11.0416(10) A, c = 12.0211(11) A, P = 91.343(8)", and Z = 4. Crystals of 8 are monoclinic, space group P2l/c, with unit-cell dimensions a = 8.7029(5) A, b = 15.6384(11) A, c = 16.5188(9) A, P = 90.096(5)", and Z = 4. Comparison of the solid state structures of [Pd(Me)(OCsH4-4-NOz)(tmeda)I (4) and its HOc6H4-4-No~ adduct (8) reveal that an electron-withdrawing substituent on the aryloxide ring leads to geometric changes in the Pd-0-C unit. Proton NMR for 5-9 and the X-ray structural data of 7 and 8 indicate that the O-H--.O hydrogen bonding in these adducts is strong both in solution and in the solid state. The thermodynamic parameters for the alkoxide-alcohol exchange in the adduct [Pd(Me)(OCH(CF3)2)(tmeda)].HOCH(CFs)z (5) have been determined with NMR spin saturation transfer techniques and provide evidence for a five-coordinate species being the key intermediate in this intramolecular exchange reaction. Furthermore, the thermodynamic parameters for adduct formation, obtained by the Scatchard method, quantify the O-H...O hydrogen bond as being strong.

The butyl and isopropyl derivatives (4I, 5Br) of chiral pool derived bis-imidazolium dehydrohexitol salts have been prepared. The ditopic N-heterocyclic carbenes 4 and 5 form dinuclear Ag(I) and Pt(II) complexes. All compounds were fully characterised by multinuclear NMR spectroscopy. The bis-imidazolium salt 4I and platinum complexes cis-[Pt(2)(μ-2)(dmso)(2)Cl(4)] and cis-[Pt(2)(μ-4)(dmso)(2)Cl(4)] were characterised by X-ray crystallography. In the case of the Pt(II) complexes, the carbene ring is positioned in a sterically preferred orientation, approximately perpendicular to the platinum coordination plane. The (1)H, (13)C, (15)N and (195)Pt NMR spectra of the platinum complexes show the presence of rotamers due to hindered rotation about the carbene-metal bond.

This report summarizes the literature from 2009 relevant to the chemistry of the group 10 transition elements. Novel coordination and organometallic compounds of these elements are presented and selected applications in the areas of catalysis, bioinorganic/medicinal chemistry are discussed.

The synthesis of new functionalised 6- and 7-membered NHC (N-heterocyclic carbene) precursors bearing anisidyl or pyridine N-substituents, both symmetrically and non-symmetrically substituted is reported. Their corresponding rhodium(i) and iridium(i) complexes, M(COD)(NHC)Cl, were also prepared and characterised. The unusual Rh(iii)/Rh(i) salt, [Rh(eta(2)-NHC-py)(2)Cl(2)][Rh(COD)Cl(2)], was obtained with one of the pyridyl-functionalised NHC ligands. Single-crystal X-ray analyses have been obtained for the majority of the complexes and NHC salts. The activity of these complexes was tested in the hydrogenation of a range of substrates with molecular hydrogen, including 1-cyclooctadiene and 2-methyl styrene, where they show enhanced activity and stability in comparison to non-functionalised NHC analogues, operating under exceptionally mild conditions (ambient temperature and atmospheric pressure).

The synthesis of the benzyl phosphinothioether derivatives Ph(2)PCH(2)CH(Et)SR and their corresponding palladium complexes are reported, where R = CH(2)Ph, R = CH(2)-3,5-Me-C(6)H(3) and R = 1-CH(2)C(10)H(7)(5). Crystallographic data obtained for the complexes Pd(3)Cl(2) and Pd(4)Cl(2) show intra- and inter-molecular pi-pi interactions between the aromatic rings on the P and S substituents, and NOE experiments for Pd(4)Cl(2) show that these interactions persist in solution. The performance of the phosphinothioether palladium complexes in aryl-aryl cross-coupling reactions is compared with that of the corresponding complex of the parent phosphinothiolato ligand Ph(2)PCH(2)CH(Et)S(-)(1). High turnover numbers up to 2000000 are reported for the coupling of bromobenzene, using the palladium dimer [Pd(1)I](2) as the catalyst precursor. Kinetic studies show a linear dependence of the reaction on catalyst loading. The effect of other variables on the cross-coupling reaction, such as temperature, solvent and base, is also reported.

The synthesis of the novel C2-symmetric diphosphine 1,4:3,6-dianhydro-2,5-bis(diphenylphosphino)-D-mannitol (ddppm) from D-isomannide is reported and its performance in asymmetric hydrogenations discussed.

Reaction of N-ligated methylpalladium(II) alkoxide and aryloxide complexes [Pd(Me)(OR)(N ∼ N)] (R = Ph, CH(CF3)2; N ∼ N tmeda (N,N,N′,N′-tetramethylethylenediamine) or bpy (2,2′-bipyridyl)) with carbon monoxide produces the corresponding methylesters in high yields. The insertion takes place either into the PdMe bond (aryloxide complexes) or into the PdOR bond (alkoxide complexes). Methylalladium(II) methoxide complexes [Pd(Me)(OMe)(N∼N)] (N ∼ N = tmeda, bpy) have been generated in situ by aryloxide- or alkoxide-methanol exchange reactions for which the equilibrium constants have been determined. The bpy-ligated methylpalladium methoxide complex undergoes insertion of CO producing either a methylpalladium methoxycarbonyl complex [Pd(ME(CO2Me)(bpy)] at −60°C) or an acylpalladium methoxycarbonyl complex [Pd(COMe)(CO2Me)(bpy)] (at −25°C); both carbonylated species could be isolated nd characterized at low temperature.