Synthesis, Characterization, and Ethylene Oligomerization and Polymerization by 2-Quinoxalinyl-6-iminopyridine Chromium Chlorides

2008 ◽  
Vol 61 (5) ◽  
pp. 397 ◽  
Author(s):  
Saliu A. Amolegbe ◽  
Maliha Asma ◽  
Min Zhang ◽  
Gang Li ◽  
Wen-Hua Sun

A series of chromium(iii) complexes ligated by N^N^N tridentate 2-quinoxalinyl-6-iminopyridine were synthesized and characterized by elemental analysis and infrared spectroscopy. Single-crystal X-ray diffraction analysis for the structure of complex C3 reveals a distorted octahedral geometry. When methylaluminoxane was employed as the co-catalyst, the chromium complexes showed high activities for ethylene oligomerization and polymerization. The distribution of oligomers obtained followed Schulz–Flory rules with high selectivity for α-olefins. Both steric and electronic effects of coordinated ligands affected the catalytic activities as well as the properties of the catalytic products. The parameters of the reaction conditions were also investigated to explore the optimum catalytic potentials of these complexes.

2010 ◽  
Vol 63 (1) ◽  
pp. 109 ◽  
Author(s):  
Liwei Xiao ◽  
Min Zhang ◽  
Rong Gao ◽  
Xiaoping Cao ◽  
Wen-Hua Sun

A series of tridentate N,N,N-nickel complexes bearing 2-(1H-2-benzimidazolyl)-6-(1-(arylimino)ethyl)pyridines was synthesized and characterized by elemental and IR spectroscopic analysis. The molecular structures of representative complexes were determined by single-crystal diffraction, and these were found to have a six-coordinate distorted octahedral geometry around the Ni centre. On treatment with Et2AlCl, all nickel complexes exhibited good catalytic activities up to 106 g mol–1(Ni) h–1 for ethylene oligomerization with major dimerization. The steric and electronic effects on catalytic activities of metal complexes as well as the influence of various reaction parameters were carefully investigated.


2019 ◽  
Vol 75 (7) ◽  
pp. 951-959 ◽  
Author(s):  
Zahra Mardani ◽  
Mohammad Hakimi ◽  
Keyvan Moeini ◽  
Fabian Mohr

The reaction between 2-[2-(aminoethyl)amino]ethanol and pyridine-2-carbaldehyde in a 1:2 molar ratio affords a mixture containing 2-({2-[(pyridin-2-ylmethylidene)amino]ethyl}amino)ethanol (PMAE) and 2-[2-(pyridin-2-yl)oxazolidin-3-yl]-N-(pyridin-2-ylmethylidene)ethanamine (POPME). Treatment of this mixture with copper(II) chloride or cadmium(II) chloride gave trichlorido[(2-hydroxyethyl)({2-[(pyridin-2-ylmethylidene)amino]ethyl})azanium]copper(II) monohydrate, [Cu(C10H16N3O)Cl3]·H2O or [Cu(HPMAE)Cl3]·H2O, 1, and dichlorido{2-[2-(pyridin-2-yl)oxazolidin-3-yl]-N-(pyridin-2-ylmethylidene)ethanamine}cadmium(II), [CdCl2(C16H18N4O)] or [CdCl2(POPME)], 2, which were characterized by elemental analysis, FT–IR, Raman and 1H NMR spectroscopy and single-crystal X-ray diffraction. PMAE is potentially a tetradentate N3O-donor ligand but coordinates to copper here as an N2 donor. In the structure of 1, the geometry around the Cu atom is distorted square pyramidal. In 2, the Cd atom has a distorted octahedral geometry. In addition to the hydrogen bonds, there are π–π stacking interactions between the pyridine rings in the crystal packing of 1 and 2. The ability of PMAE, POPME and 1 to interact with ten selected biomolecules (BRAF kinase, CatB, DNA gyrase, HDAC7, rHA, RNR, TrxR, TS, Top II and B-DNA) was investigated by docking studies and compared with doxorubicin.


1982 ◽  
Vol 37 (7) ◽  
pp. 863-871 ◽  
Author(s):  
William S. Sheldrick

AbstractThe stable ternary copper(II) complexes of ATP and ADP, [Cu(H2ATP)(phen)]2 · 7 H2O (2) and [Cu4(HADP)2(bipy)4(H2O)2(NO3)2] · 2 NO3 (3), have been isolated from aqueous solution at respective pH values of 2.8 and 4.0. Their structures have been established by single crystal X-ray diffraction. Tridentate coordination of each of the Cu atoms by ono α-, one β- and one γ-phosphate O atom of one ATP molecule is observed in 2. The binding Oα atoms occupy axial positions in a distorted octahedral geometry at Cu and the Cu- Oα interactions are weak. The other axial position is occupied by a γ-phosphate O atom of the second ATP molecule, leading to a dimeric structure. The basic structure of 3 is similar with, in this case, bidentate coordination of each of the central Cu atoms by one α- and one β-phosphate O atom of ono ADP molecule. In this case, however, the third terminal β-phosphate O atoms each bind a further Cu atom. All four Cu atoms in 3 display square pyramidal coordination. The structures of 2 and 3 are stabilised by intramolecular stacking of adenine and phenanthroline/bipyridyl systems. The significance of these structures as models for enzyme-metal ion-nucleoside polyphosphate complexes is discussed.


2020 ◽  
Vol 856 ◽  
pp. 218-223
Author(s):  
Piyarat Trikittiwong ◽  
Jedsada Maliwong

Palladium chloride impregnated on Al2O3-pillared clay (Pd/Al-PILC) was synthesized by intercalation of aluminium (III) chloride into clay interlayers and calcined at 500°C for 1 h. Subsequently, impregnated with PdCl2 and calcination at 450°C for 4 h. The modified clay catalyst was characterized by X-ray diffraction (XRD) for investigated atomic spacing of catalysts and N2 adsorption and desorption method (BET) for investigated surface area and pore volume of catalysts. The catalytic activities of Pd/Al-PILC was utilized for the reduction of nitrobenzene for synthesis aniline. The effect of various reaction factors, such as reaction time, reaction temperature, solvent system and the amount of catalyst were studied in order to optimize the reaction conditions. Aniline was prepared conveniently and efficiently via the reduction of nitrobenzene in the presence of a catalytic amount 40%Pd/Al-PILC of substrate in reflux temperature at 70°C for 4 h under extremely mild conditions.


2010 ◽  
Vol 65 (9) ◽  
pp. 1106-1112
Author(s):  
Amitabha Datta ◽  
Sébastien Pillet ◽  
Nien-Tsu Chuang ◽  
Hon Man Lee ◽  
Jui-Hsien Huang

Two new cyano-bridged trinuclear heterometallic complexes [Ca2(phen)4(ClO4)(H2O)3- Fe(CN)6]・H2O (1) and [Ca2 (phen)4(CH3COO)(H2O)3Fe(CN)6]・2H2O (2) (where phen = 1,10- phenanthroline) have been synthesized and characterized by single-crystal X-ray diffraction techniques, IR spectroscopy and thermogravimetric analysis. The structure of complex 1 features a central [Fe(CN)6]3− unit that links a monocation [Ca(phen)2(H2O)(ClO4)]+ and a dication [Ca(phen)2- (H2O)2]2+ via two trans cyanide bridges. Similarly, complex 2 also features a central [Fe(CN)6]3− unit that links a monocation [Ca(phen)2(H2O)(CH3COO)]+ and a dication [Ca(phen)2(H2O)2]2+ via two trans cyanide bridges. In 1 and 2, both Ca centers are seven-coordinated and achieve a pentagonal- bipyramidal geometry whereas the Fe center in both the complexes possesses a distorted octahedral geometry. Intra- and intermolecular hydrogen bonding networks are present in 1 and 2 that impart the overall molecular stability to both the systems.


2016 ◽  
Vol 72 (9) ◽  
pp. 697-700
Author(s):  
Yingying Wang ◽  
Meixia Wen ◽  
Zhongjun Gao ◽  
Ning Sheng

Polynuclear complexes are an important class of inorganic functional materials and are of interest particularly for their applications in molecular magnets. Multidentate chelating ligands play an important role in the design and syntheses of polynuclear metal clusters. A novel linear tetranuclear CoIIcluster, namely bis{μ3-(E)-2-[(2-oxidobenzylidene)amino]phenolato}bis{μ2-(E)-2-[(2-oxidobenzylidene)amino]phenolato}bis(1,10-phenanthroline)tetracobalt(II), [Co4(C14H11NO2)4(C12H8N2)2], was prepared under solvothermal conditions through a mixed-ligand synthetic strategy. The structure was determined by X-ray single-crystal diffraction and bulk purity was confirmed by powder X-ray diffraction. The complex molecule has a centrosymmetric tetranuclear chain-like structure and the four CoIIions are located in two different coordination environments. The CoIIions at the ends of the chain are in a slightly distorted octahedral geometry, while the two inner CoIIions are in five-coordinate distorted trigonal bipyramidal environments. A magnetic study reveals ferromagnetic CoII...CoIIexchange interactions for the complex.


2016 ◽  
Vol 71 (8) ◽  
pp. 869-874 ◽  
Author(s):  
Gao-Feng Wang ◽  
Xiao Zhang ◽  
Shu-Wen Sun ◽  
Hong Sun ◽  
Xia Yang ◽  
...  

AbstractTwo Mn(II) complexes, {[Mn(BIPMO)2Cl2] · 2(H2O)}n (1) and {[Mn(BIPMO)2(SCN)2] · 2(CH3OH)}n (2) (BIPMO = bis(4-(1H-imidazol-1-yl)phenyl)methanone) with V-shaped BIPMO ligands, were synthesized and characterized by IR spectroscopy and elemental analyses along with their single-crystal X-ray diffraction analyses. The Mn(II) ions in 1 and 2 are both six-coordinated to four nitrogen atoms of four BIPMO ligands and two anions (Cl− for 1, and SCN− for 2) to form a distorted octahedral geometry.


2017 ◽  
Vol 72 (1) ◽  
pp. 83-87 ◽  
Author(s):  
Gao-Feng Wang ◽  
Xiao Zhang ◽  
Zhao-Rong Liu ◽  
Yu-Chun Wang ◽  
Hong-Shi Jiang ◽  
...  

AbstractTwo complexes, {Mn(hfac)2(BIPMO)}n (1), {Cu(hfac)2(BIPMO)}n (2) [hfac=1,1,1,5,5,5-hexafluoro-pentane-2,4-dionato(–), BIPMO=bis(4-(1H-imidazol-1-yl)phenyl)methanone], with the V-shaped ligands were synthesized and characterized by infrared spectroscopy, elemental analyses, along with single-crystal X-ray diffraction analyses. The X-ray diffraction studies have shown that the metal ions in 1 and 2 are both six-coordinated to two nitrogen atoms of two BIPMO ligands and four oxygen atoms of two hfac ligands to form a distorted octahedral geometry. Each BIPMO ligand acts as a bridging ligand to link two adjacent metal(II) atoms to form a helical chain in the crystal structure.


2021 ◽  
Vol 16 (2) ◽  
pp. 260-266
Author(s):  
Li-Hua Wang ◽  
Fan-Yuan Kong ◽  
Xi-Shi Tai

A new six-coordinated Mn(II) coordination polymer, [Mn(L1)(L2)2]n (L1 = 2-aminopyrimidine, HL2 = 3-bromo-2-hydroxybenzaldehyde) was synthesized by 3-bromo-2-hydroxybenzaldehyde, NaOH, 2-aminopyrimidine and manganese(II) acetate dihydrate. The Mn(II) coordination polymer was structural characterized by elemental analysis and single crystal X-ray diffraction. The results show that each Mn(II) ion is six-coordinated with two phenolic hydroxyl O atoms from two 3-bromo-2-hydroxybenzaldehyde ligands (O1 and O4), two formyl group O atoms from two 3-bromo-2-hydroxybenzaldehyde ligands (O2 and O3), and two N atoms from two 2-aminopyrimidine molecules (N1A and N2), and forms a distorted octahedral coordination geometry. The Mn(II) coordination polymer displays a 1D chained structure by the bridge effect of 2-aminopyrimidine N atoms. The catalytic activities of Mn(II) coordination polymer and Pd@Mn(II) coordination polymer for hydrogenation of 1,3-butadiene have been investigated. The Pd@Mn(II) coordination polymer catalyst shows the good catalytic activity and selectivity in  the hydrogenation of 1,3-butadiene. The 1,3-butadiene conversion is 61.3% at 70 °C, and the selectivity to total butene is close to 100%. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 


2013 ◽  
Vol 11 (1) ◽  
pp. 116-122 ◽  
Author(s):  
Amitabha Datta ◽  
Jui-Hsien Huang ◽  
Jack Clegg ◽  
Pei-Hsin Liu ◽  
Sheng-Jie Chuang

AbstractA tridentate hydrazone precursor, N′-[1-(pyridin-2-yl)ethylidene]acetohydrazide (L) (1:1 refluxed product of acetichydrazide and 2-acetylpyridine), produced two octahedral CuII and NiII derivatives, [CuL2]·NO3 (1) and [NiL2]·ClO4·H2O (2). Both are subjected to X-ray diffraction system, and structural investigation shows that the central metal atom (CuII or NiII) adopts a distorted octahedral geometry with N4O2 donor sets by coordination of a pair of independent hydrazone precursors. Besides X-ray study, IR and UV-vis spectra, thermal analysis and room temperature magnetic moments are utilized for establishing significant characteristics of both complexes. It is apparent that the M-Npyridine bonds are slightly longer than the M-Nimino bonds, Cu1-N1 and Cu1-N4 [2.300(2) and 2.038(2) Å] for 1 and Ni1-N1 and Ni1-N4 [2.075(2) and 2.084(1) Å] for 2, Cu1-N2 and Cu1-N5 [2.062(1) and 1.932(1) Å] for 1 and Ni1-N2 and Ni1-N5 [2.008(2) and 1.975(2) Å] for 2, respectively. As per our observation, the effective magnetic moment value (µeff) is found to be 1.77 B.M. for 1 and 3.06 BM for 2, respectively.


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