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María Andérez-Fernández, Lydia K Vogt, Steffen Fischer, Wei Zhou, Haijun Jiao, Marcel Garbe, Saravanakumar Elangovan, Kathrin Junge, Henrik Junge, Ralf Ludwig, Matthias Beller
For the first time, structurally defined manganese pincer complexes catalyze the dehydrogenation of aqueous methanol to hydrogen and carbon dioxide, which is a transformation of interest with regard to the implementation of a hydrogen and methanol economy. Excellent long-term stability was demonstrated for the Mn-PNPiPr catalyst, as a turnover of more than 20 000 was reached. In addition to methanol, other important hydrogen carriers were also successfully dehydrogenated.
December 2, 2016: Angewandte Chemie
Esther Moya, Luis Gerardo Natera, Carlomagno Cardenas, Emanuele Astarita, Vittorio Bellotti, Manel Ribas
Many of the described labral-reconstruction procedures are purely arthroscopic. This approach only allows segmentary reconstructions. For more extensive reconstructions, surgical dislocation of the hip still represents the more suitable approach. We present an arthroscopy-assisted procedure combined with an anterior mini-open approach, which could be considered for reconstruction of nonrepairable labral lesions located in the posterior aspect of the acetabulum and massive reconstructions in cases of global-pincer femoroacetabular impingement and protrusio acetabuli...
October 2016: Arthroscopy Techniques
Ulukan İnan, Selim Harmanşa, Hakan Ömeroğlu
OBJECTIVES: This study aims to assess the experience gained in a single institution in the treatment of mixed type femoroacetabular impingement (FAI) using safe surgical hip dislocation (SSHD) technique. PATIENTS AND METHODS: In this study, 22 hips of 21 patients (7 males, 14 females; mean age 33.8±10.6 years; range 19-52 years) treated by SSHD technique in our clinic between October 2009 and October 2014 were retrospectively evaluated. Preoperative and final Harris hip scores (HHS) and alpha angles were compared...
December 2016: Eklem Hastalıkları Ve Cerrahisi, Joint Diseases & related Surgery
Ben Yiu-Wing Wong, Hok-Lai Wong, Yi-Chun Wong, Mei-Yee Chan, Vivian Wing-Wah Yam
A new class of cyclometalated tetradentate alkynylgold(III) complexes has been successfully synthesized by post-synthetic modification. Through the judicious design and choice of pincer ligands, post-synthetic cyclization could be achieved to produce the robust and structurally rigid class of tetradentate gold(III) C^N^C^C complexes with high photoluminescence quantum yields of up to 0.49 in solution and 0.78 in doped thin films at room temperature, at least an order of magnitude higher than those of the structurally related uncyclized tridentate alkynylgold(III) analogues...
November 29, 2016: Angewandte Chemie
Ava Behnia, Paul D Boyle, Mahmood A Fard, Johanna M Blacquiere, Richard J Puddephatt
The combination of a palladium(ii) precursor with a diimine-phenol ligand and an oxidant (H2O2 or O2) under different conditions has, serendipitously, given both a molecular square and a molecular tetrahedron by self-assembly of building blocks comprising palladium(ii) centres coordinated to the oxidised forms of the ligand.
November 28, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Dirong Gong, Xuequan Zhang, Kuo-Wei Huang
A new family of cobalt complexes (CoCl2-H, CoCl2-Me, CoCl2-iPr, CoBr2-H, CoBr2-Me, CoBr2-iPr, CoI2-H, CoI2-Me, and CoI2-iPr) supported by a PN(3) ligand (6-(N,N'-di-t-butylphosphino)-2-pyrazol-yl-aminopyridine) have been prepared and fully characterized by FT-IR, elemental analysis, and X-ray analysis. The X-ray analysis reveals a trigonal bipyramidal conformation in the solid state for all representative complexes, CoCl2-H, CoBr2-H, CoBr2-iPr and CoI2-Me. The cobalt center is chelated by the PN(3) ligand through the pyridinyl nitrogen, the pyrazol nitrogen and the phosphorus donor, with a long Co-P bond distance indicating a labile character...
November 24, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Qiang-Qiang Ma, Ting Liu, Shujun Li, Jie Zhang, Xuenian Chen, Hairong Guan
Highly efficient catalytic reduction of CO2 with catecholborane has been developed by using bis(phosphinite) pincer ligated palladium thiolate complexes. Turnover frequencies up to 1780 h(-1) have been achieved at room temperature under an atmospheric pressure of CO2. These thiolate complexes represent the most efficient homogeneous catalysts known to date for the reduction of CO2 to methanol under mild conditions.
November 23, 2016: Chemical Communications: Chem Comm
Yusuke Kawamura, Kenji Ikeda, Shunichiro Fujiyama, Tetsuya Hosaka, Masahiro Kobayashi, Satoshi Saitoh, Hitomi Sezaki, Norio Akuta, Fumitaka Suzuki, Yoshiyuki Suzuki, Yasuji Arase, Hiromitsu Kumada
OBJECTIVE: The aim of this study was to clarify the usefulness of a no-touch pincer ablation procedure that uses bipolar electrodes to prevent intra-subsegmental tumor recurrence after radiofrequency ablation (RFA) for patients with hepatocellular carcinoma (HCC). METHODS: We studied 303 consecutive patients with HCC (single nodule and tumor diameter of ≤30 mm) who received RFA between January 2005 and April 2015; 268 patients received touch ablation using a monopolar or bipolar RFA device, and 35 received no-touch ablation using a bipolar RFA device...
November 15, 2016: Hepatology Research: the Official Journal of the Japan Society of Hepatology
Katsuhiko Takeuchi, Hiro-Omi Taguchi, Ippei Tanigawa, Shota Tsujimoto, Tsukasa Matsuo, Hiromasa Tanaka, Kazunari Yoshizawa, Fumiyuki Ozawa
The Pt(0) complex [Pt(PPh3 )(Eind2 -BPEP)] with a pyridine-based PNP-pincer-type phosphaalkene ligand (Eind2 -BPEP) has a highly planar geometry around Pt with ∑(Pt)=358.6°. This coordination geometry is very uncommon for formal d(10) complexes, and the Pd and Ni homologues with the same ligands adopt distorted tetrahedral geometries. DFT calculations reveal that both the Pt and Pd complexes are M(0) species with nearly ten valence electrons on the metals whereas their atomic orbital occupancies are evidently different from one another...
November 9, 2016: Angewandte Chemie
Lucy Currie, Julio Fernandez-Cestau, Luca Rocchigiani, Benoît Bertrand, Simon J Lancaster, David L Hughes, Helen Duckworth, Saul T E Jones, Dan Credgington, Thomas J Penfold, Manfred Bochmann
A new family of cyclometallated gold(III) thiolato complexes based on pyrazine-centred pincer ligands has been prepared, (C^N(pz) ^C)AuSR, where C^N(pz) ^C=2,6-bis(4-Bu(t) C6 H4 )pyrazine dianion and R=Ph (1), C6 H4 tBu-4 (2), 2-pyridyl (3), 1-naphthyl (1-Np, 4), 2-Np (5), quinolinyl (Quin, 6), 4-methylcoumarinyl (Coum, 7) and 1-adamantyl (8). The complexes were isolated as yellow to red solids in high yields using mild synthetic conditions. The single-crystal X-ray structures revealed that the colour of the deep-red solids is associated with the formation of a particular type of short (3...
November 9, 2016: Chemistry: a European Journal
Doaa Domyati, Sydney L Hope, Reza Latifi, Micah D Hearns, Laleh Tahsini
Six new Cu(I) complexes with pincer N-heterocyclic carbene (NHC) ligands of the type 2,6-bis(3-alkylimidazol-2-ylidene)pyridine, I(R)(CNC), and 2,6-bis(3-alkylimidazol-2-ylidene)methylpyridine, I(R)(C^N^C), where R = Me, Et, and (i)Pr have been synthesized using Cu precursors and bis(imidazolium) salts. All of these compounds, namely, [Cu2(IMe(CNC))2](PF6)2, 1; [Cu2(IEt(CNC))2](PF6)2, 2; [Cu2(I(i)Pr(CNC))2](PF6)2, 3; [Cu(IMe(C^N^C))](PF6), 4; [Cu(IEt(C^N^C))](PF6), 5; and [Cu(I(i)Pr(C^N^C))](PF6), 6, have been characterized by (1)H and (13)C NMR spectroscopies, elemental analysis, solution conductivity, and electrochemical studies...
November 3, 2016: Inorganic Chemistry
Alex J Kosanovich, Wei-Chun Shih, Rodrigo Ramírez-Contreras, Oleg V Ozerov
A novel PNN-type pincer ligand has been accessed via imine reduction with LiAlH4 to provide the phosphine diamino proligand, PN(H)N(H) (1). The ligand, 1, as well as PN(H)P can be metallated directly, via N-H cleavage, with L2ReOX2(OEt) precursors to access six-coordinate (PNP)ReOCl2 (2) and (PNN(H))ReOX2 (3-Cl, X = Cl; 3-Br, X = Br) in good yield. 3-Cl and 3-Br undergo dehydrohalogenation upon treatment with NEt3, furnishing the five-coordinate phosphine/diamido PNN-type compounds (PNN)ReOX (4-Cl, X = Cl; 4-Br, X = Br) in excellent yield, presenting as a mixture of rotameric diasteromers...
November 3, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Leila Tabrizi, Hossein Chiniforoshan
Three new ruthenium(ii) complexes of NCN pincer and phenylcyanamide derivative ligands of the formula [Ru(L)(Ph2phen)(3,5-(NO2)2pcyd)], 1, [Ru(L)(Me2phen)(3,5-(NO2)2pcyd)], 2, and [Ru(L)(Cl2phen)(3,5-(NO2)2pcyd)], 3 (HL: 5-methoxy-1,3-bis(1-methyl-1H-benzo[d]imidazol-2-yl)benzene, 3,5-(NO2)2pcyd: 3,5-(NO2)2pcyd, Ph2phen: 4,7-diphenyl-1,10-phenanthroline, Me2phen: 4,7-dimethyl-1,10-phenanthroline, Cl2phen: 4,7-dichloro-1,10-phenanthroline) have been synthesized and studied as potential photosensitizers (PSs) in photodynamic therapy (PDT)...
November 2, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Yu-Peng Zhou, Miriam Karni, Shenglai Yao, Yitzhak Apeloig, Matthias Driess
The synthesis, reactivity, and electronic structure of the unique germylone iron carbonyl complex [SiNSi]Ge(0) →Fe(CO)4 is reported. The compound was obtained in 49 % yield from the reaction of the bis(N-heterocyclic silylenyl)pyridine pincer ligand SiNSi (1,6-C5 NH3 -[EtNSi(N(t) Bu)2 CPh]2 ) with GeCl2 ⋅(dioxane) to give the corresponding chlorogermyliumylidene chloride precursor [SiNSi]Ge(II) Cl(+)  Cl(-) , which was further reduced with K2 Fe(CO)4 . Single-crystal X-ray diffraction analysis of [SiNSi]Ge→Fe(CO)4 revealed that the Ge(0) center adopts a trigonal-pyramidal geometry with a Si-Ge-Si angle of 95...
November 2, 2016: Angewandte Chemie
Faan-Fung Hung, Shui-Xing Wu, Wai-Pong To, Wai-Lun Kwong, Xiangguo Guan, Wei Lu, Kam-Hung Low, Chi-Ming Che
Two classes of cationic palladium(II) acetylide complexes containing pincer-type ligands, 2,2':6',2″-terpyridine (terpy) and 2,6-bis(1-butylimidazol-2-ylidenyl)pyridine (C^N^C), were prepared and structurally characterized. Replacing terpy with the strong σ-donating C^N^C ligand having two N-heterocyclic carbene units results in the Pd(II) acetylide complexes to display phosphorescence at room temperature and stronger intermolecular interactions in the solid state. X-ray crystal structures of [Pd(terpy)(CΞCPh)]PF6 (1) and [Pd(C^N^C)(CΞCPh)]PF6 (7) reveal that the complex cations are arranged in a one-dimensional stacking structure with pair-like PdII∙∙∙PdII contacts of 3...
October 31, 2016: Chemistry, An Asian Journal
Marc Perez, Saravanakumar Elangovan, Anke Spannenberg, Kathrin Junge, Matthias Beller
For the first time an easily accessible and well-defined manganese N,N,N-pincer complex catalyzes the transfer hydrogenation of a broad range of ketones with good to excellent yields. This cheap earth abundant-metal based catalyst provides access to useful secondary alcohols without the need of hydrogen gas. Preliminary investigations to explore the mechanism of this transformation are also reported.
October 28, 2016: ChemSusChem
Miguel Peña-López, Patrick Piehl, Saravanakumar Elangovan, Helfried Neumann, Matthias Beller
A novel catalytic hydrogen-autotransfer protocol for the atom-efficient α-alkylation of ketones with readily available alcohols is presented. The use of manganese complexes bearing non-innocent PNP pincer ligands enabled the functionalization of a broad range of valuable ketones, including 2-oxindole, estrone 3-methyl ether, and testosterone. Mechanistic investigations suggest the participation of an intramolecular amidate-assisted alcohol-dehydrogenation process.
October 27, 2016: Angewandte Chemie
Omer Kirshenboim, Sebastian Kozuch
Halogen bonds (XB) are no longer newcomers in the chemistry family. However, XB in hypervalent halogens has not been thoroughly studied. We provide a molecular orbital explanation of the shape and strength of XBs in hypervalent halogens and other species, focusing on the charge transfer and electrostatic aspects of these bonds. Our results show that σ-holes (and subsequently the XBs associated with them) can be easily divided and bent by the influence of equatorial substituents. Inductive effect of both the equatorial and axial groups can affect these distortions, but also the angle between the equatorial ligands has a large influence on the shape of the σ-holes and the molecular orbitals acting as electron acceptor...
October 26, 2016: Journal of Physical Chemistry. A
Anja H Greif, Peter Hrobárik, Jochen Autschbach, Martin Kaupp
Previous relativistic quantum-chemical predictions of unusually large (1)H and (13)C NMR chemical shifts for ligand atoms directly bonded to a diamagnetic uranium(vi) center (P. Hrobárik, V. Hrobáriková, A. H. Greif and M. Kaupp, Angew. Chem., Int. Ed., 2012, 51, 10884) have been revisited by two- and four-component relativistic density functional methods. In particular, the effect of the exchange-correlation response kernel, which had been missing in the previously used two-component version of the Amsterdam Density Functional program, has been examined...
October 26, 2016: Physical Chemistry Chemical Physics: PCCP
David W Shaffer, Indrani Bhowmick, Arnold L Rheingold, Charlene Tsay, Brooke N Livesay, Matthew P Shores, Jenny Y Yang
We describe the structural and electronic impacts of modifying the bridging atom in a family of Co(ii) pincer complexes with the formula Co(t-Bu)2P(E)Py(E)P(t-Bu)2Br2 (Py = pyridine, E = CH2, NH, and O for compounds 1-3, respectively). Structural characterization by single crystal X-ray diffraction indicates that compounds 1 and 3 are 5-coordinate complexes with both bromides bound to the Co(ii) ion, while compound 2 is square planar with one bromide in the outer coordination sphere. The reduction potentials of 1-3, characterized by cyclic voltammetry, are consistent with the increasing electron-withdrawing character of the pincer ligand as the linker (E) between the pyridine and phosphine arms becomes more electronegative...
October 24, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
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