Models for the basis of enantioselection in palladium mediated C-H activation reactions

Models are proposed to account for the basis of enantioselection in cyclopalladation reactions, which result in the formation of planar chiral palladacycles. This analysis is extended to a palladium catalysed enantioselective C-H activation reaction proceeding via the intermediacy of a chiral palladacycle. (C) 2010 Elsevier Ltd. All rights reserved

Synthesis, characterization and catalytic activity in Suzuki-Miyaura coupling of palladacycle complexes with n-butyl-substituted N-heterocyclic carbene ligands

A series of monomeric palladacycle complexes bearing n-butyl-substituted N-heterocyclic carbenes, namely [Pd(NHC)X(dmba)] (dmba: dimethylbenzylamine and [Pd(NHC)X(ppy)]; NHC: 1-n-butyl-3-substituted benzylimidazol-2-ylidene; ppy: 2-phenylpyridine), were prepared either by transmetallation from the corresponding silver carbene complexes or by the reaction of the corresponding acetate-bridged palladacycle dimer with N-heterocyclic carbene ligands in high yields. The palladium(II) complexes were characterized using elemental analyses, APCI-MS, H-1 NMR and C-13 NMR spectroscopies. These complexes are efficient in the Suzuki-Miyaura coupling reaction between phenylboronic acid and aryl bromides

Cysteamine-palladium complex ([Pd(mu-OAc)(ppy)](2), ppy:2-phenylpyridine, PhMe)-modified peroxidase biosensor immobilized on a gold electrode

WOS: 000345208600007PubMed ID: 23885923A new peroxidase biosensor was developed using cysteamine-palladium complex-modified gold electrode. The principle of the measurements is based on monitoring increase in the oxidation potential of palladium complex (at + 0.47 V vs Ag/AgCl) using amperometric detection. In the optimization studies of the biosensor, effects of enzyme amount, palladium complex amount, and duration of SAM formation on biosensor responses were investigated to optimize the bioactive layer. The biosensor has a fast response time of less than 10 s to hydrogen peroxide (H2O2), with a linear range of 5.0 x 10(-6) to 150 x 10(-6) M and a detection limit of 3.38 x 10(-6) M

Synthesis, X-ray structures, and catalytic activities of (kappa(2)-C,N)-palladacycles bearing imidazol-2-ylidenes

WOS: 000266638700008Quaternisation of methylimidazole (1) by methyl substituted benzyl bromides afforded imidazolium salts (2) which were converted to (kappa(2)-C, N)-palladacycles bearing imidazol-2-ylidenes 6 or 7, by either in situ deprotonation or via Ag-NHC intermediate (3), using the bridged palladacycles 4 or 5, respectively. The palladacycles 6 and 7 were characterized by elemental analysis; NMR spectroscopy and the molecular structure of 6c and 7c were determined by X-ray crystallography. The complexes 6 and 7 display high activity in Suzuki-Miyaura coupling of a range of aryl bromides. (C) 2009 Elsevier B.V. All rights reserved.TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [104T203]; Adnan Menderes UniversityAdnan Menderes University [FEF-07006, FEF-07013, FBE-08001]Funding of our research from the TUBITAK (Project No.: 104T203) and Adnan Menderes University (Project Nos.: FEF-07006, FEF-07013 and FBE-08001) is gratefully acknowledged

Crystallographic and conformational analysis of 1,3-bis(2,4-dimethoxyphenyl)imidazolidine-2-thione

WOS: 000240142800002The molecular and crystal structures of the title compound, C19H22N2O4S, were determined by single crystal X-ray diffraction technique. The title compound crystallizes in space group F d d 2, with a = 30.785(3) angstrom, b = 10.6455(9) angstrom, c = 11.0036(8) angstrom, Z = 8, D-calc = 1.379(2) g cm(-3), mu(Mo-K-alpha) = 0.207 mm(-1), and its crystal system is orthorhombic. The structure was solved by direct methods and refined to a final R = 0.042 for 1530 reflections with I > 2 sigma (I). There is a half-independent molecule in the asymmetric unit. The title molecule has twofold rotational symmetry along with the C-S bond. Classically no hydrogen bond is found in the crystal structure. The crystal structure is stabilized by pi-pi stacking and edge to face (C-H...pi-ring) interactions. To elucidate conformational features and steric hindrances of the title molecule, selected torsion angle is varied from -180 degrees to +180 degrees in every 10 degrees and thus molecular energy profile is calculated by PM3 semi-empirical method

The synthesis and structural characterization of a N-heterocyclic carbene-substituted palladacycle

WOS: 000247730600011Reaction of {[Pd(dmba)(mu-Cl)](2)} (dmba=(CH3)(2)NCH2C6H4) with ail ill situ generated N-heterocyclic carbene (NHC=1,3-dimesitylimidazolidin-2-ylidene) afforded crystals containing [chloro-(1,3-dimesitylimidazolidin-2-ylidene)(N,N-dimethylaminobenzyl-C-1,N) palladium(II)] (VII). Molecular and crystal structures of the title compound have been determined by single crystal X-ray diffraction technique. Complex VII crystallizes in space group Pi, with a=13.685(3) angstrom, b = 13.590(2) angstrom, c - 16.229(3) angstrom, alpha = 87.162(13)degrees, beta=70.514(15)degrees, y=84.153(16)degrees, Z=4, D-Calcd=1.367g cm(-3). There are two independent molecules in the asymmetric unit

Preparation and crystal structure of binuclear chloro{6-[[chloro(triphenylphosphine)platinum](mesitylimino)methyl]pyridin-2-yl}bis(triphenylphosphine)platinum(II)

WOS: 000261912300011Treatment of N,N'-bis(mesityl)pyridine-2,6-carboxyimidoyldichloride, 1, in toluene solution with [Pt(PPh3)(4)] at 100 degrees C afforded a novel platinacyclic compound, 3, in 63% yield, instead of the expected compound 2. The molecular and crystal structures of the title compound, 3, have been determined by the single crystal X-ray diffraction technique. The coordination geometries around the Pt atoms are distorted square-planar. In the crystal structure, the molecules are linked by a pair of C-H center dot center dot center dot N hydrogen bonds into a centrosymmetric dinner with an R-2(2) (16) ring, centred at (1/2,1/2,1/2). (C) 2008 Elsevier Ltd. All rights reserved.Faculty of Arts and Sciences, Ondokuz Mayis University, TurkeyOndokuz Mayis University [F279]; Dokuz Eylul UniversityDokuz Eylul University [04.KB.FEN.100]The authors acknowledge the Faculty of Arts and Sciences, Ondokuz Mayis University, Turkey, for the use of the Stoe IPDS-II diffractometer (purchased under Grant No. F279 of the University Research Fund) and Dokuz Eylul University Research Funds (Project No.: 04.KB.FEN.100)

Enamines of 1,3-dimethylbarbiturates and their symmetrical palladium(II) complexes: synthesis, characterization and biological activity

Three 1,3-dimethylbarbiturate-enamine derivatives and their symmetrical palladium(II) complexes were prepared and characterized by spectroscopic methods. In addition, the structures of the complexes were determined by single-crystal X-ray diffraction. The X-ray diffraction studies revealed the geometry around the Pd(II) atom in each complex is almost perfectly square-planar. Also, the ligands and their palladium(II) complexes were tested for antifungal and antibacterial activity against various clinical and food-borne microorganisms, revealing promising biological activities