共查询到20条相似文献,搜索用时 562 毫秒
1.
Ram N. Patel Manoj K. Kesharwani Anurag Singh Dheerendra K. Patel Mukesh Choudhary 《Transition Metal Chemistry》2008,33(6):733-738
Three new polyamine Ni(II) complexes, namely [Ni(trien)(phen)](BF4)2
1, [Ni(trien)(bipy)](ClO4)2
2 and [Ni(trien)(en)](ClO4)2
3 [trine = triethylenetetramine, phen = 1,10-phenanthroline, bipy = 2,2′-bipyridyl, en = ethylenediamine] have been synthesized
and characterized by physico-chemical and spectroscopic methods. Complexes 1 and 2 crystallize in monoclinic space group P21/c, and possess a distorted octahedral geometry. Significant hydrogen bonding interactions are found in both complexes. 相似文献
2.
K. Srikanth V. R. Marathe Manoj K. Mishra 《International journal of quantum chemistry》2002,89(6):535-549
ZINDO/S calculations on cis‐Ru(4,4′‐dicarboxy‐2,2′‐bipyridine)2(X)2 and cis‐Ru(5,5′‐dicarboxy‐2,2′‐bipyridine)2(X)2 complexes where X = Cl?, CN?, and NCS? reveal that the highest occupied molecular orbital (HOMO) of these complexes has a large amplitude on both the nonchromophoric ligand X and the central ruthenium atom. The lowest‐energy metal to ligand charge transfer (MLCT) transition in these complexes involves electron transfer from ruthenium as well as the halide/pseudohalide ligand to the polypyridyl ligand. The contribution of the halide/pseudohalide ligand(X) to the HOMO affects the total amount of charge transferred to the polypyridyl ligand and hence the photoconversion efficiency. The virtual orbitals involved in the second MLCT transition in 4,4′‐dicarboxy‐2,2′‐bipyridine complexes have higher electron density on the ? COOH group compared to the lowest unoccupied molecular orbital and hence a stronger electronic coupling with the TiO2 surface and higher injection efficiency at shorter wavelengths. In comparison, the virtual orbitals involved in the second MLCT transition in 5,5′‐dicarboxy‐2,2′‐bipyridine complexes have lesser electron density on the ? COOH group, leading to a weaker electronic coupling with the TiO2 surface and therefore lower efficiency for electron injection at shorter wavelengths for these complexes. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002 相似文献
3.
A Noble‐Metal‐Free Nickel(II) Polypyridyl Catalyst for Visible‐Light‐Driven Hydrogen Production from Water
下载免费PDF全文
![点击此处可从《Chemphyschem》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Yong‐Jun Yuan Dr. Hong‐Wei Lu Ji‐Ren Tu Dr. Yong Fang Dr. Zhen‐Tao Yu Dr. Xiao‐Xing Fan Prof. Zhi‐Gang Zou 《Chemphyschem》2015,16(14):2925-2930
The complex [Ni(bpy)3]2+ (bpy=2,2′‐bipyridine) is an active catalyst for visible‐light‐driven H2 production from water when employed with [Ir(dfppy)2(Hdcbpy)] [dfppy=2‐(3,4‐difluorophenyl)pyridine, Hdcbpy=4‐carboxy‐2,2′‐bipyridine‐4′‐carboxylate] as the photosensitizer and triethanolamine as the sacrificial electron donor. The highest turnover number of 520 with respect to the nickel(II) catalyst is obtained in a 8:2 acetonitrile/water solution at pH 9. The H2‐evolution system is more stable after the addition of an extra free bpy ligand, owing to faster catalyst regeneration. The photocatalytic results demonstrate that the nickel(II) polypyridyl catalyst can act as a more effective catalyst than the commonly utilized [Co(bpy)3]2+. This study may offer a new paradigm for constructing simple and noble‐metal‐free catalysts for photocatalytic hydrogen production. 相似文献
4.
Huilu Wu Jin Kong Yanhui Zhang Furong Shi Yuchen Bai Xiaoli Wang 《Phosphorus, sulfur, and silicon and the related elements》2013,188(4):519-529
Abstract A six-coordinate picrate nickel(II) complex based on the V-shaped ligand 1,3-bis(1-benzylbenzimidazol-2-yl)-2-thiapropane (L), with the composition [Ni(L)2](pic)2, has been synthesized and characterized systematically. The crystal structure of the Ni(II) complex is a six-coordinated octahedron, which is considerably close to ideal octahedral geometry with N4S2 donors of the two ligands. Biological activities of compounds were investigated using electronic absorption spectroscopy, fluorescence spectroscopy, and viscosity measurements. The results suggested that both ligand L and Ni(II) complex bind to DNA in an intercalative binding mode, and DNA-binding affinity of the Ni(II) complex is stronger than that of ligand L. [Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental files: Additional figures.] 相似文献
5.
Narayanaswamy Srinivasan Panneerselvam Valarmathi Subbiah Thirumaran Samuele Ciattini 《Transition Metal Chemistry》2010,35(7):815-819
Three complexes of a dithiocarbamate ligand (dbpdtc = benzyl(4-(benzylamino)phenyl)dithiocarbamate), namely [Ni(dbpdtc)2] (1), [Ni(dbpdtc)(NCS)(PPh3)] (2) and [Ni(dbpdtc)(PPh3)2]ClO4 (3) have been prepared. The complexes were characterized by IR, electronic spectroscopy and cyclic voltammetry. A single-crystal
X-ray structural analysis was carried out for complex 1 and showed that the nickel is in a distorted square planar environment with a NiS4 chromophore. For the two mixed ligand complexes, the thioureide ν
C–N values were shifted to higher wavenumbers compared to [Ni(dbpdtc)2], suggesting increased strength of the thioureide bond due to the presence of the π-accepting phosphine. Electronic spectral studies suggest square planar geometries for the complexes. Cyclic voltammetry showed
easier reduction of nickel(II) to nickel(I) in the mixed ligand complexes compared to [Ni(dbpdtc)2]. 相似文献
6.
M. Badea R. Olar D. Marinescu G. Vasile S. Stoleriu 《Journal of Thermal Analysis and Calorimetry》2005,80(3):679-682
Summary This paper reports the investigation of the thermal stability of two new complexes with allylacetoacetate anion, Cu(C7H9O3)2 (1) and Ni(C7H9O3)2(OH2)2 (2), respectively. The bonding and stereochemistry of the complexes have been characterized by IR, electronic and EPR spectra. The main decomposition steps were evidenced. The two complexes exhibit a different thermal behaviour. Thus, the copper complex suffers an oxidative degradation of allylacetoacetate ligand leading to copper carbonate, which is decomposed to copper oxide. The Ni(II) complex lose the water molecules first and then the organic ligand decomposition occurs. An intermediary malonaldehyde complex seems to be obtained. Complex (1) presents in vitro antimicrobial activity. 相似文献
7.
Understanding and Practical Use of Ligand and Metal Exchange Reactions in Thiolate‐Protected Metal Clusters to Synthesize Controlled Metal Clusters
下载免费PDF全文
![点击此处可从《Chemical record (New York, N.Y.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Yoshiki Niihori Sakiat Hossain Sachil Sharma Bharat Kumar Wataru Kurashige Yuichi Negishi 《Chemical record (New York, N.Y.)》2017,17(5):473-484
It is now possible to accurately synthesize thiolate (SR)‐protected gold clusters (Aun(SR)m) with various chemical compositions with atomic precision. The geometric structure, electronic structure, physical properties, and functions of these clusters are well known. In contrast, the ligand or metal atom exchange reactions between these clusters and other substances have not been studied extensively until recently, even though these phenomena were observed during early studies. Understanding the mechanisms of these reactions could allow desired functional metal clusters to be produced via exchange reactions. Therefore, we have studied the exchange reactions between Aun(SR)m and analogous clusters and other substances for the past four years. The results have enabled us to gain deep understanding of ligand exchange with respect to preferential exchange sites, acceleration means, effect on electronic structure, and intercluster exchange. We have also synthesized several new metal clusters using ligand and metal exchange reactions. In this account, we summarize our research on ligand and metal exchange reactions. 相似文献
8.
9.
《Journal of Coordination Chemistry》2012,65(2):205-213
A new terephthalato-bridged binuclear nickel(II) complex with a tetraazamacrocyclic compound as the terminal ligand, [Ni 2 (cth) 2 (µ-TPHA)](ClO 4 ) 2 (1) [cth= rac -5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane] has been synthesized and characterized. According to X-ray crystallographic studies on the solvated species 1·2CH 3 OH, each Ni(II) ion lies in a distorted octahedral environment, and the terephthalato ligand bridges two Ni(II) ions in a bis bidentate fashion. Cryomagnetic measurements revealed Curie-Weiss behaviour with è = m 1.4 K. Such behaviour may be due to a very weak intramolecular superexchange interaction through the extended bridge, a weak intermolecular exchange interaction or the local zero-field splitting of Ni(II) ions. 相似文献
10.
Plamen Kirilov Hubert Matondo Patricia Vicendo Jean‐Christophe Garrigues Michel Baboulne Hoang‐Phuong Nguyen Isabelle Rico‐Lattes 《应用有机金属化学》2006,20(2):125-129
The synthesis of a number of new 2,2′‐bipyridine ligands functionalized with bulky amino side groups is reported. Three homoleptic polypyridyl ruthenium (II) complexes, [Ru(L)3]2+ 2(PF6?), where L is 4,4′‐dioctylaminomethyl‐2,2′‐bipyridine (Ru4a), 4,4′‐didodecylaminomethyl‐2,2′‐bipyridine (Ru4b) and 4,4′‐dioctadodecylaminomethyl‐2,2′‐bipyridine (Ru4c), have been synthesized. These compounds were characterized and their photophysical properties examined. The electronic spectra of three complexes show pyridyl π → π* transitions in the UV region and metal‐to‐ligand charge transfer bands in the visible region. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
11.
Ramin Zibaseresht 《合成通讯》2020,50(6):904-915
AbstractThe novel bipyridine–terpyridine–phenazine ligand 6-pyrid-(tetrapyrido[2,3-a:2′,3′-c:3′′,2′′-h:2′′′,3′′′-j]phenazine (I) was prepared by condensation reaction of 5,6-diamino-l,10-phenanthroline (4) and 2-(pyrid-2′-yl)-1,10-phenanthroline-5,6-dione (6) and characterized using conventional methods. Poor solubility of the ligand led us to the preparation of its Ru(II) complexes to investigate the change in its solubility for further characterizing the ligand on the metal ion. [Ru(ttp)(I)](PF6)2 complex was prepared using the reaction of the ligand (I) and [Ru(ttp)Cl3] complex, where ttp is 4′-(4-Methylphenyl)-2,2′:6′,2′′-terpyridine. A different route for the preparation of [Ru(ttp)(I)](PF6)2 was introduced. Synthesis of the ligand (I) on the complex by a condensation reaction of [Ru(ttp)(6)](PF6)2, where ligand (6) is 2-(pyrid-2′-yl)-1,10-phenanthroline-5,6-dione, with 5,6-diamino-l,10-phenanthroline (4) was conducted. The spectroscopic measurements of both products which have been obtained through the two different routes were compared. We observed that the NMR, LC-MS, and UV spectra of the both products were identical. 相似文献
12.
《Journal of Coordination Chemistry》2012,65(3):167-173
Abstract Crystals of [Zn(trien)I]I (trien=triethylenetetramine C6N4H18) are orthorhombic. The space group is P212121, with four molecules in the unit cell of dimensions a=11.97(1), b=13.72(1), c=8.12(1)Å. A total of 2029 independent reflections was measured with a Siemens A.E.D. automatic diffractometer using MoKα radiation. The structure was refined by full-matrix least-squares to a conventional R factor of 0.041 for 1435 observed reflections. The coordination around the central zinc atom is square pyramidal with the zinc atom 0.71 Å above the plane of the four nitrogen atoms of the ligand molecule. The values of coordination bond lengths, Zn-N(prim) 2.13 Å, Zn-N(sec) 2.19 Å, Zn-I 2.59 Å fall all in the range expected for covalent bonds. The molecular structure is discussed in comparison with that of [Cu(trien)SCN]CNS. 相似文献
13.
Summary A series of new cobalt(III) complexes of general formula [Co(AA)(trien)]Xn (where AA = tropolone, acetoacetanilide, ethylacetoacetate, biguanide, 2-guanidinobenzimidazole, propylenediamine, picolylamine, 2,2-dipyridyl, 3-aminopyridine, picolinic acid and quinaldinic acid, trien = triethylenetetramine, X=Cl–, Br–, I– and n=2–3) have been synthesized and characterized by elemental analysis, electronic and i.r. spectra, equivalent weight, conductance and magnetic measurements. The electronic spectra of the complexes exhibit one or two ligand field bands atca. 20000 and 29000 cm–1 due to the1
A
1g
1
T
1g
and1
A
1g
1
T
2g
transitions respectively. Conductance measurements indicate the triunivalent nature of [Co(tropolone)(trien)]I3, [Co(picolylamine)(trien)]I3, [Co(3-aminopyridine)(trien)]I3, [Co(2,2-dipyridyl)(trien)]Cl3, [Co(biguanide)(trien)]I3, [Co(propylenediamine)(trien)]I3 and biunivalent nature of [Co(picolinate)(trien)]Cl2, [Co(quinaldinate)(trien)]Cl2, [Co(acetoacetanilido)(trien)]Cl2, and [Co(ethylacetoacetato)(trien)]I2. Equivalent weight determination by the ion-exchange resin (H+ form) method gives the values of molecular weights which are consistent with the theory. The complexes are diamagnetic. 相似文献
14.
《Journal of Coordination Chemistry》2012,65(13):1527-1536
Template reactions of salicylaldehyde or pentanedione with 3-aminopropanethiol (Hapt) in the presence of Ni(II) ions are described. When salicylaldehyde was used, a dinuclear Ni(II) complex [Ni(bit′)]2 (2) (H2bit′?=?2-(3′-mercaptopropyliminomethyl)phenol) was obtained instead of the reported trinuclear one [Ni(bit)]3 (1) (H2bit?=?2-(2′-mercaptoethyliminomethyl)phenol) containing 2-aminoethanethiol (Haet). Starting from pentanedione, the expected dinuclear complex [Ni(pit′)]2 (H2pit′?=?2-(3′-mercaptopropylimino)pentanol) was not obtained, nor was [Ni(pit)]2 (3) (H2pit?=?2-(2′-mercaptoethylimino)pentanol). The complex was found to be a trinuclear Ni(II) complex [Ni{Ni(apt)2}2]2+ (4), as confirmed by elemental analysis, electronic and NMR spectra. Complexes 1 and 3 were also synthesized and their 13C, 1H–1H and 13C–1H?NMR spectra are discussed in detail. The X-ray crystal structure of 2 shows that two Ni(II) ions are connected by the thiolate donor atom from each ligand, resulting in a four-membered ring. Differences in reactivity and properties is due to the presence of an additional methylene group in the aminoalkane arm of the ligand. 相似文献
15.
The hydrothermal reactions of Ni(II), 1,2,3‐benzenetricarboxylic acid (1,2,3‐H3btc) and 4,4′‐bipyridine (4,4′‐bpy)/1,2‐bis(4‐pyridyl)ethane (bpa) yield two layered nickel(II) coordination polymers, [Ni2(1,2,3‐btc)(OAc)‐(4,4′‐bpy)2(H2O)]·2H2O ( 1 ) and [Ni(ip)(bpa)] ( 2 ) (ip=isophthalate), respectively. Both complexes are 2‐D coordination network based on 1‐D Ni‐carboxylate chains. The 1,2,3‐btc ligand adopts 3‐bridging mode in complex 1 , but transformed to isophthalate (ip) ligand through decarboxylation in 2 . The formation of the two complexes indicates that hydrothermal conditions andin‐situ ligand reaction have significant effect on constructing coordination polymers. 相似文献
16.
《Journal of Coordination Chemistry》2012,65(4):660-669
Tris(N-ethylbenzimidazol-2-ylmethyl)amine (Etntb), [Mn(Etntb)(DMF)(H2O)](pic)2 (1), and [Ni(Etntb)(DMF)(H2O)](pic)2 (2) (pic?=?picrate) have been synthesized and characterized by elemental analyses, molar conductivities, UV–Visible spectra, and IR spectra. Single-crystal X-ray diffraction revealed that the complexes have the same arrangement with distorted octahedral coordination geometries. DNA-binding properties of the free ligand, 1, and 2 have been investigated by electronic absorption, fluorescence, and viscosity measurements. The results suggest that the ligand and its complexes bind DNA via intercalation, and their binding affinity for DNA follows the order 2?>?1?> ligand. 相似文献
17.
《Journal of Coordination Chemistry》2012,65(13):2220-2228
A new series of Cu(II), Ni(II), and Co(II) complexes have been synthesized from 3-formylchromoniminopropylsilatrane (C19H24O5N2Si) (2) and 3-formylchromoniminopropyltriethoxysilane (1). Silatrane ligand (C19H24O5N2Si) (2) has been synthesized by the reaction between 3-aminopropyltriethoxysilane and 3-formylchromone followed by a treatment with triethanolamine. The nature of bonding and the geometry of the complexes have been deduced from elemental analyses, magnetic susceptibility, infrared, electronic, 1H NMR, 13C NMR, and ESR spectral studies. The electronic absorption spectra and magnetic susceptibility measurements of the complexes indicate square planar geometry for Cu(II) and Ni(II) and tetrahedral geometry for Co(II). The redox behavior of copper complexes was studied by cyclic voltammetry. The biological activity of the ligand and metal complexes has been studied on Klebsiella pneumoniae, Staphylococcus aureus, Escherichia Coli, and Bacillus subtilis by the well diffusion method using acetonitrile as solvent. The zone of inhibition values were measured at 37°C for 24 h. Antimicrobial screening tests show better results for the metal complexes than the ligand. 相似文献
18.
《Journal of Coordination Chemistry》2012,65(1-4):321-334
Abstract Acid dissociation constants for two conformational isomers of dicyclohexylcyclam, cis-anti-cis, (P) and cis-syn-cis, (N) have been determined at 25, 35 and 40°C, and thermodynamic data are estimated. It was found that (N) shows very different behaviour from (P). Stability constants of (P) and (N) toward Ni(II), Cu(II) and Zn(II) have been determined by pH-titration at 25°C by using a ligand exchange reaction. It is found that the (P) complex is more stable for Ni(II) and the (N) complex is more stable for Cu(II). Contributions of the cyclohexyl group to the macrocyclic effect (ME) have been also estimated by considering basicity corrections. It is found that substitution of the cyclohexyl group in cyclam increases ME only for the Ni(II) complex of (P). 相似文献
19.
Timothy J. Hubin Nathaniel W. Alcock Howard J. Clase Daryle H. Busch 《Supramolecular chemistry》2013,25(2):261-276
Abstract The novel high spin Ni2+ complexes of the topologically constrained tetraazamacrocycles (1–4) [4,11-dimethyl-1,4,8,11 - tetraazabicyclo[6.6.2]hexadecane (1); 4,10-dimethyl-1,4,7,10-tetraazabicyclo[6.5.2]pentadecane (2); 4,10-dimethyl-1,4,7,10-tetraazabicyclo[5.5.2]tetradecane (3); racemic-4,5,7,7,11,12,14,14-octamethyl-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane (4)] show striking properties. Potentiometric titrations of the ligands 2 and 4 revealed them to be proton sponges, as reported earlier for 1 [1]. Ligand 3 is less basic, losing its last proton with a pK = 11.3(2). Despite high proton affinities, complexation reactions in the absence of protons successfully yielded Ni2+ complexes in all cases. The X-ray crystal structures of Ni(1)(acac)+, Ni(3)(acac)+ and Ni(1)(OH2)2 2+ demonstrate that the ligands enforce a distorted octahedral geometry on Ni2+ with two cis sites occupied by other ligands. Magnetic measurements and electronic spectroscopy on the corresponding Ni(L)Cl2 (L = 1–3) complexes reveal that all are high spin and six-coordinate with typical magnetic moments. In contrast, [Ni(4)Cl+] is five-coordinate with a slightly higher magnetic moment and its own characteristic electronic spectrum. The extra methyl groups on ligand 4 define a shallow cavity, sterically allowing only one chloride ligand to bind to the nickel(II) ion. 相似文献
20.
Michael Nussbaum Dr. Oliver Schuster Prof. Dr. Martin Albrecht 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(51):17517-17527
A ditopic benzobis(carbene) ligand precursor was prepared that contained a chelating pyridyl moiety to ensure co‐planarity of the carbene ligand and the coordination plane of a bound octahedral metal center. Bimetallic ruthenium complexes comprising this ditopic ligand [L4Ru‐C,N‐bbi‐C,N‐RuL4] were obtained by a transmetalation methodology (C,N‐bbi‐C,N=benzobis(N‐pyridyl‐N′‐methyl‐imidazolylidene). The two metal centers are electronically decoupled when the ruthenium is in a pseudotetrahedral geometry imparted by a cymene spectator ligand (L4=[(cym)Cl]). Ligand exchange of the Cl?/cymene ligands for two bipyridine or four MeCN ligands induced a change of the coordination geometry to octahedral. As a consequence, the ruthenium centers, separated through space by more than 10 Å, become electronically coupled, which is evidenced by two distinctly different metal‐centered oxidation processes that are separated by 134 mV (L4=[(bpy)2]; bpy=2,2′‐bipyridine) and 244 mV (L4=[(MeCN)4]), respectively. Hush analysis of the intervalence charge‐transfer bands in the mixed‐valent species indicates substantial valence delocalization in both complexes (delocalization parameter Γ=0.41 and 0.37 in the bpy and MeCN complexes, respectively). Spectroelectrochemical measurements further indicated that the mixed‐valent RuII/RuIII species and the fully oxidized RuIII/RuIII complexes gradually decompose when bound to MeCN ligands, whereas the bpy spectators significantly enhance the stability. These results demonstrate the efficiency of carbenes and, in particular, of the bbi ligand scaffold for mediating electron transfer and for the fabrication of molecular redox switches. Moreover, the relevance of spectator ligands is emphasized for tailoring the degree of electronic communication through the benzobis(carbene) linker. 相似文献