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131.
Linda GötzkeKerstin Gloe Katrina A. JolliffeLeonard F. Lindoy Axel HeineThomas Doert Anne JägerKarsten Gloe 《Polyhedron》2011,30(5):708-714
The interaction of di(2-picolyl)amine (1) and its secondary N-substituted derivatives, N-(4-pyridylmethyl)-di(2-picolyl)amine (2), N-(4-carboxymethyl-benzyl)-di(2-picolyl)amine (3), N-(4-carboxybenzyl)-di(2-picolyl)amine (4), N-(1-naphthylmethyl)-di(2-picolyl)amine (5), N-(9-anthracenylmethyl)-di(2-picolyl)amine (6), 1,4-bis[di(2-picolyl)aminomethyl]benzene (7), 1,3-bis[di(2-picolyl)aminomethyl]benzene (8) and 2,4,6-tris[di(2-picolyl)amino]triazine (9) with Ni(II) and/or Zn(II) nitrate has resulted in the isolation of [Ni(1)(NO3)2], [Ni(2)(NO3)2], [Ni(3)(NO3)2], [Ni(4)(NO3)2]·CH3CN, [Ni(5)(NO3)2], [Ni(6)(NO3)2], [Ni2(7)(NO3)4], [Ni2(8)(NO3)4], [Ni3(9)(NO3)6]·3H2O, [Zn(3)(NO3)2]·0.5CH3OH, [Zn(5)(NO3)2], [Zn(6)(NO3)2], [Zn(8)(NO3)2] and [Zn2(9)(NO3)4]·0.5H2O. X-ray structures of [Ni(4)(NO3)2]·CH3CN, [Ni(6)(NO3)2] and [Zn(5)(NO3)2] have been obtained. Both nickel complexes exhibit related distorted octahedral coordination geometries in which 4 and 6 are tridentate and bound meridionally via their respective N3-donor sets, with the remaining coordination positions in each complex occupied by a monodentate and a bidentate nitrato ligand. For [Ni(4)(NO3)2]·CH3CN, intramolecular hydrogen bond interactions are present between the carboxylic OH group on one complex and the oxygen of a monodentate nitrate on an adjacent complex such that the complexes are linked in chains which are in turn crosslinked by intermolecular offset π-π stacking between pyridyl rings in adjacent chains. In the case of [Ni(6)(NO3)2], two weak CH?O hydrogen bonds are present between the axial methylene hydrogen atoms on one complex and the oxygen of a monodentate nitrate ligand on a second unit such that four hydrogen bonds link pairs of complexes; in addition, an extensive series of π-π stacking interactions link individual complex units throughout the crystal lattice. The X-ray structure of [Zn(5)(NO3)2] shows that the metal centre once again has a distorted six-coordinated geometry, with the N3-donor set of N-(1-naphthylmethyl)-di(2-picolyl)amine (5) coordinating in a meridional fashion and the remaining coordination positions occupied by a monodentate and a bidentate nitrato ligand. The crystal lattice is stabilized by weak intermolecular interactions between oxygens on the bound nitrato ligands and aromatic CH hydrogens on adjacent complexes; intermolecular π-π stacking between aromatic rings is also present. 相似文献
132.
Analysis of dye degradation products and assessment of the dye purity in dye‐sensitized solar cells 下载免费PDF全文
133.
Dominik Grtner Andr Luiz Stein Sabine Grupe Johannes Arp Axel JacobivonWangelin 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(36):10691-10695
Stable C O linkages are generally unreactive in cross‐coupling reactions which mostly employ more electrophilic halides or activated esters (triflates, tosylates). Acetates are cheap and easily accessible electrophiles but have not been used in cross‐couplings because the strong C O bond and high propensity to engage in unwanted acetylation and deprotonation. Reported herein is a selective iron‐catalyzed cross‐coupling of diverse alkenyl acetates, and it operates under mild reaction conditions (0 °C, 2 h) with a ligand‐free catalyst (1–2 mol %). 相似文献
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136.
Synthesis,Structure, and Reactivity of Diazene Adducts: Isolation of iso‐Diazene Stabilized as a Borane Adduct 下载免费PDF全文
Dipl.‐Chem. Fabian Reiß Prof. Dr. Axel Schulz Dr. Alexander Villinger 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(37):11800-11811
This work describes the synthesis and full characterization of a series of GaCl3 and B(C6F5)3 adducts of diazenes R1?N?N?R2 (R1=R2=Me3Si, Ph; R1=Me3Si, R2=Ph). Trans‐Ph?N?N?Ph forms a stable adduct with GaCl3, whereas no adduct, but instead a frustrated Lewis acid–base pair is formed with B(C6F5)3. The cis‐Ph?N?N?Ph ? B(C6F5)3 adduct could only be isolated when UV light was used, which triggers the isomerization from trans‐ to cis‐Ph?N?N?Ph, which provides more space for the bulky borane. Treatment of trans‐Ph?N?N?SiMe3 with GaCl3 led to the expected trans‐Ph?N?N?SiMe3 ? GaCl3 adduct but the reaction with B(C6F5)3 triggered a 1,2‐Me3Si shift, which resulted in the formation of a highly labile iso‐diazene, Me3Si(Ph)N?N; stabilized as a B(C6F5)3 adduct. Trans‐Me3Si?N?N?SiMe3 forms a labile cis‐Me3Si?N?N?SiMe3 ? B(C6F5)3 adduct, which isomerizes to give the transient iso‐diazene species (Me3Si)2N?N ? B(C6F5)3 upon heating. Both iso‐diazene species insert easily into one B?C bond of B(C6F5)3 to afford hydrazinoboranes. All new compounds were fully characterized by means of X‐ray crystallography, vibrational spectroscopy, CHN analysis, and NMR spectroscopy. All compounds were further investigated by DFT and the bonding situation was assessed by natural bond orbital (NBO) analysis. 相似文献
137.
Gabasch H Knop-Gericke A Schlögl R Penner S Jenewein B Hayek K Klötzer B 《The journal of physical chemistry. B》2006,110(23):11391-11398
The adsorption and thermal desorption of Zn and ZnO on Pd(111) was studied in the temperature range between 300 and 1300 K with TDS, LEED, and CO adsorption measurements. At temperatures below 400 K, multilayer growth of Zn metal on the Pd(111) surface takes place. At a coverage of 0.75 ML of Zn, a p(2 x 2)-3Zn LEED structure is observed. Increasing the coverage to 3 ML results in a (1 x 1) LEED pattern arising from an ordered Zn multilayer on Pd(111). Thermal desorption of the Zn multilayer state leads to two distinct Zn desorption peaks: a low-temperature desorption peak (400-650 K) arising from upper Zn layers and a second peak (800-1300 K) originating from the residual 1 ML Zn overlayer, which is more strongly bound to the Pd(111) surface and blocks CO adsorption completely. Above 650 K, this Zn adlayer diffuses into the subsurface region and the surface is depleted in Zn, as can be deduced from an increased amount of CO adsorption sites. Deposition of >3 ML of Zn at 750 K leads to the formation of a well-ordered Pd-Zn alloy exhibiting a (6 x 4 square root 3/3)rect. LEED structure. CO adsorption measurements on this surface alloy indicate a high Pd surface concentration and a strong reduction of the CO adsorption energy. Deposition of Zn at T > 373 K in 10(-6) mbar of O2 leads to the formation of an epitaxial (6 x 6) ZnO overlayer on Pd(111). Dissociative desorption of ZnO from this overlayer occurs quantitatively both with respect to Zn and O2 above 750 K, providing a reliable calibration for both ZnO, Zn, and oxygen coverage. 相似文献
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139.
Damir A. Safin Maria G. Babashkina Michael Bolte Axel Klein 《Phosphorus, sulfur, and silicon and the related elements》2013,188(12):2426-2432
The reaction of O,O′-diisopropylphosphoric acid isothiocyanate (iPrO)2P(O)NCS with 2-methylaniline 2-MeC6H4NH2, 2,6-dimethylaniline 2,6-Me2C6H3NH2, or 2,4,6-trimethylaniline 2,4,6-Me3C6H2NH2 leads to the N-phosphorylated thioureas RNHC(S)NHP(O)(OiPr)2 (R = 2-MeC6H4?, HLI ; 2,6-Me2C6H3?, HLII ; 2,4,6-Me3C6H2?, HLIII ). Reaction of the potassium salts of HLI –III with Ni(II) in aqueous EtOH leads to [Ni(LI–III-N,S)2] ([NiLI–III 2 ]) chelate complexes. The compounds obtained were investigated by 1H, 31P{1H} NMR spectroscopy and microanalysis. The molecular structure of the thiourea HLIII was elucidated by single crystal X-ray diffraction analysis. Single crystal X-ray diffraction studies showed that HLIII forms both intra- and intermolecular hydrogen bonds, which in turn leads to the formation of polymeric chains. One of the intermolecular hydrogen bonds is of the type N?H…S. Moreover, the formation of intermolecular C?H…η6-phenyl interactions was established. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. 相似文献
140.
Filipe E. Antunes Luís Alves Claudia Duarte Björn Lindman Björn Klotz Axel Böttcher 《Journal of Dispersion Science and Technology》2013,34(9):1368-1372
Physical properties of aqueous solutions of hydrophobically modified crosslinked polyacrylic acids change quite extensively as the polymer is charged up. A study is carried out concerning the similarities between two polymer ionization processes, that is, by pH increment and anionic surfactant addition. The two processes charge the polymer by distinctly different mechanisms. At sufficiently high pH the carboxylic groups of the polymer are virtually all ionized and the polymer is, therefore, fully charged. The effective repulsion among the charged groups due to the entropy of the counterions promotes an increased stiffness as well as an expansion of the polymer particles. We investigate here how the ionization and swelling will be if, instead of high pH, the polymer is at low pH conditions but associated to ionic surfactants. Surfactants associate to the polymer both in a noncooperative way by the binding of individual surfactant molecules and in a cooperative way as micelles since the polymer promotes surfactant self-assembly. This binding leads to a highly charged polymer-surfactant complex and leads to an osmotic swelling as well. The swelling and the gelation were monitored by rheology and dynamic light scattering, of polymer solutions by varying the pHs and adding ionic surfactants at low pH. The results show that ionization by surfactants and by pH lead to approximately the same gelation degree, as can be seen by similar viscosity values. Both processes result in dramatic viscosity increases, up to 8 orders of magnitude. More hydrophobic surfactants, with longer alkyl chain, are shown to be more efficient as enhancers of swelling and gelation. The network that is formed at high pH or at sufficiently high concentration of surfactant can be weakened or even disrupted if monovalent or divalent salts are added, demonstrating the role of counterion entropy. 相似文献