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1.
Dr. Suman Maji Dr. Jason C.‐M. Lee Yu‐Jhang Lu Dr. Chang‐Li Chen Mu‐Cheng Hung Dr. Peter P.‐Y. Chen Prof. Steve S.‐F. Yu Prof. Sunney I. Chan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(13):3955-3968
The dioxygen activation of a series of CuICuICuI complexes based on the ligands ( L ) 3,3′‐(1,4‐diazepane‐ 1,4‐diyl)bis(1‐{[2‐(dimethylamino)ethyl](methyl)amino}propan‐2‐ol) ( 7‐Me ) or 3,3′‐(1,4‐diazepane‐1,4‐diyl)bis(1‐{[2‐(diethylamino)ethyl](ethyl)amino}propan‐2‐ol) ( 7‐Et ) forms an intermediate capable of mediating facile O‐atom transfer to simple organic substrates at room temperature. To elucidate the dioxygen chemistry, we have examined the reactions of 7‐Me , 7‐Et , and 3,3′‐(1,4‐diazepane‐1,4‐diyl)bis[1‐(4‐methylpiperazin‐1‐yl)propan‐2‐ol] ( 7‐N‐Meppz ) with dioxygen at ?80, ?55, and ?35 °C in propionitrile (EtCN) by UV‐visible, 77 K EPR, and X‐ray absorption spectroscopy, and 7‐N‐Meppz and 7‐Me with dioxygen at room temperature in acetonitrile (MeCN) by diode array spectrophotometry. At both ?80 and ?55 °C, the mixing of the starting [CuICuICuI( L )]1+ complex ( 1 ) with O2‐saturated propionitrile (EtCN) led to a bright green solution consisting of two paramagnetic species: the green dioxygen adduct [CuIICuII(μ‐η2:η2‐peroxo)CuII( L )]2+ ( 2 ) and the blue [CuIICuII(μ‐O)CuII( L )]2+ species ( 3 ). These observations are consistent with the initial formation of [CuIICuII(μ‐O)2CuIII( L )]1+ ( 4 ), followed by rapid abortion of this highly reactive species by intercluster electron transfer from a second molecule of complex 1 to give the blue species 3 and subsequent oxygenation of the partially oxidized [CuIICuICuI( L )]2+ ( 5 ) to form the green dioxygen adduct 2 . Assignment of 2 to [CuIICuII(μ‐η2:η2‐peroxo)CuII( L )]2+ is consistent with its reactivity with water to give H2O2 and the blue species 3 , as well as its propensity to be photoreduced in the X‐ray beam during X‐ray absorption experiments at room temperature. In light of these observations, the development of an oxidation catalyst based on the tricopper system requires consideration of the following design criteria: 1) rapid dioxygen chemistry; 2) facile O‐atom transfer from the activated cluster to substrate; and 3) a suitable reductant to rapidly regenerate complex 1 to accomplish efficient catalytic turnover. 相似文献
2.
Direct Evidence for a [4+2] Cycloaddition Mechanism of Alkynes to Tantallacyclopentadiene on Dinuclear Tantalum Complexes as a Model of Alkyne Cyclotrimerization 下载免费PDF全文
Keishi Yamamoto Dr. Hayato Tsurugi Prof. Dr. Kazushi Mashima 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(32):11369-11377
A dinuclear tantalum complex, [Ta2Cl6(μ‐C4Et4)] ( 2 ), bearing a tantallacyclopentadiene moiety, was synthesized by treating [(η2‐EtC?CEt)TaCl3(DME)] ( 1 ) with AlCl3. Complex 2 and its Lewis base adducts, [Ta2Cl6(μ‐C4Et4)L] (L=THF ( 3 a ), pyridine ( 3 b ), THT ( 3 c )), served as more active catalysts for cyclotrimerization of internal alkynes than 1 . During the reaction of 3 a with 3‐hexyne, we isolated [Ta2Cl4(μ‐η4:η4‐C6Et6)(μ‐η2:η2‐EtC?CEt)] ( 4 ), sandwiched by a two‐electron reduced μ‐η4:η4‐hexaethylbenzene and a μ‐η2:η2‐3‐hexyne ligand, as a product of an intermolecular cyclization between the metallacyclopentadiene moiety and 3‐hexyne. The formation of arene complexes [Ta2Cl4(μ‐η4:η4‐C6Et4Me2)(μ‐η2:η2‐Me3SiC?CSiMe3)] ( 7 b ) and [Ta2Cl4(μ‐η4:η4‐C6Et4RH)(μ‐η2:η2‐Me3SiC?CSiMe3)] (R=nBu ( 8 a ), p‐tolyl ( 8 b )) by treating [Ta2Cl4(μ‐C4Et4)(μ‐η2:η2‐Me3SiC?CSiMe3)] ( 6 ) with 2‐butyne, 1‐hexyne, and p‐tolylacetylene without any isomers, at room temperature or low temperature were key for clarifying the [4+2] cycloaddition mechanism because of the restricted rotation behavior of the two‐electron reduced arene ligands without dissociation from the dinuclear tantalum center. 相似文献
3.
George E. Cutsail Nicole L. Gagnon Andrew D. Spaeth William B. Tolman Serena DeBeer 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(27):9212-9217
Valence‐to‐Core (VtC) X‐ray emission spectroscopy (XES) was used to directly detect the presence of an O?O bond in a complex comprising the [CuII2(μ‐η2:η2‐O2)]2+ core relative to its isomer with a cleaved O?O bond having a [CuIII2(μ‐O)2]2+ unit. The experimental studies are complemented by DFT calculations, which show that the unique VtC XES feature of the [CuII2(μ‐η2:η2‐O2)]2+ core corresponds to the copper stabilized in‐plane 2p π peroxo molecular orbital. These calculations illustrate the sensitivity of VtC XES for probing the extent of O?O bond activation in μ‐η2:η2‐O2 species and highlight the potential of this method for time‐resolved studies of reaction mechanisms. 相似文献
4.
Isaac Garcia‐Bosch Dr. Xavi Ribas Dr. Miquel Costas 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(7):2113-2122
Reactions of the unsymmetric dicopper(II) peroxide complex [CuII2(μ‐η1:η1‐O2)(m‐XYLN3N4)]2+ ( 1 O2 , where m‐XYL is a heptadentate N‐based ligand), with phenolates and phenols are described. Complex 1 O2 reacts with p‐X‐PhONa (X=MeO, Cl, H, or Me) at ?90 °C performing tyrosinase‐like ortho‐hydroxylation of the aromatic ring to afford the corresponding catechol products. Mechanistic studies demonstrate that reactions occur through initial reversible formation of metastable association complexes [CuII2(μ‐η1:η1‐O2)(p‐X‐PhO)(m‐XYLN3N4)]+ ( 1 O2 ?X‐PhO) that then undergo ortho‐hydroxylation of the aromatic ring by the peroxide moiety. Complex 1 O2 also reacts with 4‐X‐substituted phenols p‐X‐PhOH (X=MeO, Me, F, H, or Cl) and with 2,4‐di‐tert‐butylphenol at ?90 °C causing rapid decay of 1 O2 and affording biphenol coupling products, which is indicative that reactions occur through formation of phenoxyl radicals that then undergo radical C? C coupling. Spectroscopic UV/Vis monitoring and kinetic analysis show that reactions take place through reversible formation of ground‐state association complexes [CuII2(μ‐η1:η1‐O2)(X‐PhOH)(m‐XYLN3N4)]2+ ( 1 O2 ?X‐PhOH) that then evolve through an irreversible rate‐determining step. Mechanistic studies indicate that 1 O2 reacts with phenols through initial phenol binding to the Cu2O2 core, followed by a proton‐coupled electron transfer (PCET) at the rate‐determining step. Results disclosed in this work provide experimental evidence that the unsymmetric 1 O2 complex can mediate electrophilic arene hydroxylation and PCET reactions commonly associated with electrophilic Cu2O2 cores, and strongly suggest that the ability to form substrate?Cu2O2 association complexes may provide paths to overcome the inherent reactivity of the O2‐binding mode. This work provides experimental evidence that the presence of a H+ completely determines the fate of the association complex [CuII2(μ‐η1:η1‐O2)(X‐PhO(H))(m‐XYLN3N4)]n+ between a PCET and an arene hydroxylation reaction, and may provide clues to help understand enzymatic reactions at dicopper sites. 相似文献
5.
Xuting Wang Dr. Yanxia Zhao Shida Gong Prof. Bin Liu Prof. Qian‐Shu Li Prof. Ji‐Hu Su Prof. Biao Wu Prof. Xiao‐Juan Yang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(38):13302-13310
Reactions of the dimeric cobalt complex [(L?Co)2] ( 1 , L=[(2,6‐iPr2C6H3)NC(Me)]2) with polyarenes afforded a series of mononuclear and dinuclear complexes: [LCo(η4‐anthracene)] ( 2 ), [LCo(μ‐η4:η4‐naphthalene)CoL] ( 3 ), and [LCo(μ‐η4:η4‐phenanthrene)CoL] ( 4 ). The pyrene complexes [{Na2(Et2O)2}{LCo(μ‐η3:η3‐pyrene)CoL}] ( 5 ) and [{Na2(Et2O)3}{LCo(η3‐pyrene)}] ( 6 ) were obtained by treating precursor 1 with pyrene followed by reduction with Na metal. These complexes contain three potential redox active centers: the cobalt metal and both α‐diimine and polyarene ligands. Through a combination of X‐ray crystallography, EPR spectroscopy, magnetic susceptibility measurement, and DFT computations, the electronic configurations of these complexes were studied. It was determined that complexes 2 – 4 have a high‐spin CoI center coupled with a radical α‐diimine ligand and a neutral polyarene ligand. Whereas, the ligand L in complexes 5 and 6 has been further reduced to the dianion, the cobalt remains in a formal (I) oxidation state, and the pyrene molecule is either neutral or monoanionic. 相似文献
6.
The title coordination polymer, poly[[aqua(μ5‐1,1′‐biphenyl‐2,2′,5,5′‐tetracarboxylato)bis[μ2‐1,4‐bis(1H‐imidazol‐1‐yl)benzene]dicadmium(II)] dihydrate], {[Cd2(C16H6O8)(C12H10N4)2(H2O)]·2H2O}n, was crystallized from a mixture of 1,1′‐biphenyl‐2,2′,5,5′‐tetracarboxylic acid (H4bpta), 1,4‐bis(1H‐imidazol‐1‐yl)benzene (1,4‐bib) and cadmium nitrate in water–dimethylformamide. The crystal structure consists of two crystallographically independent CdII cations, with one of the CdII cations possessing a slightly distorted pentagonal bipyramidal geometry. The second CdII centre is coordinated by carboxylate O atoms and imidazole N atoms from two separate 1,4‐bib ligands, displaying a distorted octahedral CdN2O4 geometry. The completely deprotonated bpta4− ligand, exhibiting a new coordination mode, bridges five CdII cations to form one‐dimensional chains viaμ3‐η1:η2:η1:η2 and μ2‐η1:η1:η0:η0 modes, and these are further linked by 1,4‐bib ligands to form a three‐dimensional framework with a (42.64)(4.62)(43.65.72) topology. The structure of the coordination polymer is reinforced by intermolecular hydrogen bonding between carboxylate O atoms, aqua ligands and crystallization water molecules. The solid‐state photoluminescence properties were investigated and the complex might be a candidate for a thermally stable and solvent‐resistant blue fluorescent material. 相似文献
7.
Xiancui Zhu Yuzhe Jiang Jun Chen Shaowu Wang Zeming Huang Shan Zhu Xu Zhao Wenrun Yue Jun Zhang Weikang Wu Xiangyang Zhong 《中国化学》2020,38(5):478-488
A series of dinuclear rare‐earth metal alkyl complexes {[μ‐η2:η1:η1‐3‐( L NCH)(CH2SiMe3)Ind]RE(CH2SiMe3)(THF)}2 ( L 1 = 2‐tBuC6H4, RE = Y, Gd, Dy, Er, Yb; L 2 = 2,4,6‐Me3C6H2, RE = Dy, Er; Ind = indolyl) and {[μ‐η2:η1:η1‐3‐( L NCH2)Ind]RE(CH2SiMe3)(THF)}2 ( L 1, RE = Y, Dy, Er, Yb; L 2, RE = Er, Yb) bearing 3‐arylamido functionalized indolyl ligands having diverse bonding modes with metal ions were synthesized either by the insertion reaction of the imino group to the RE—C bond or by the alkane elimination reaction. In the preparation of above complexes, rare‐earth metal alkyl complexes [μ‐η5:η1:η1‐3‐( L 2NCH)(CH2SiMe3)Ind]Gd(CH2SiMe3)(THF)}2 with a μ‐η5:η1:η1 coordination mode to the gadolinium ion and {[μ‐η3:η1:η1‐3‐( L 2NCH2)Ind]Dy(CH2SiMe3)(THF)}2 with a μ‐η3:η1:η1 coordination mode to the dysprosium ion were unexpectedly isolated. The reactions of 3‐( L 2N=CH)Ind with Er(CH2SiMe3)3(THF)2 at room temperature, generated a tetranuclear imino‐indolyl erbium intermediate {[μ‐η1:η1‐3‐( L 2N=CH)Ind]Er(CH2SiMe3)2(THF)}4, which can transform into the amido functionalized indolyl erbium complex in hot toluene. Moreover, the reactivities of the newly synthesized ytterbium complex with N‐heterocyclic compounds were investigated, affording the corresponding products of the mixed pyridyl‐indolyl, imidazolyl‐indolyl, and ortho‐metalated complexes. The yttrium complexes showed a high regioselectivity and steroselectivity for the isoprene polymerization with 1,4‐trans selectivity up to 91.7% and 1,4‐cis selectivity up to 96.1% in the presence of cocatalysts, respectively. 相似文献
8.
The addition of [(L)4Ca(I)Mes] (Lewis base L=thf, Et2O) to mesityl copper(I) and the transmetalation reaction of mesityl copper(I) with activated calcium are suitable pathways for the synthesis of dimesityl cuprates(I) of calcium. However, the structures of the calcium cuprates(I) depend on the preparative procedure. The transmetalation reaction leads to the formation of [Mes‐Cu‐Mes]? anions whereas the addition yields dinuclear [(Mes‐Cu)2(μ‐Mes)]? anions. The solvent‐separated counterions are [Ca(thf)6]2+ and [(thf)5CaI]+, respectively. In contrast to these findings, the addition of [(L)4Ca(I)Mes] to mesityl copper(I) in an Et2O/toluene mixture led to formation of tetrameric solvent‐free iodocalcium dimesityl cuprate(I) [ICa(μ‐η1,η6‐Mes2Cu)]4, representing a rare example of a heavy Normant‐type organocuprate. 相似文献
9.
Philipp von Grebe Dr. Pablo J. Sanz Miguel Prof. Dr. Bernhard Lippert 《无机化学与普通化学杂志》2012,638(11):1691-1698
Acid‐base and ligating properties of three bis(substituted)pyrazine (pz) and pyrimidine (pym) ligands (pyrazine‐2, 5‐dicarboxylic acid, 2, 5‐pzdcH2, 2, 3‐bis(pyridine‐2‐yl)pyrazine, 2, 3‐bppz, pyrimidine‐4, 6‐dicarboxylic acid, 4, 6‐pmdcH2) toward cis‐PtIIa2 (a = NH3, a2 = en, a2 = 2, 2′‐bpy) have been studied. Combinations of pz‐N/pym‐N with donor atoms of the substituents lead to 5‐membered platinum chelates, but exclusive N, N‐coordination through the pyridyl substituents of 2, 3‐bppz can lead to a 7‐membered platinum chelate with a characteristic L‐shape of the resulting cation. It is observed for PtII(2, 2′‐bpy), yet not for PtII(en), and is a consequence of differences in sterical interactions between the 2, 3‐bppz ligand and the coligands of PtII. 相似文献
10.
Michael Kampf Rainer Richter Lothar Hennig Andreas Eidner Jens Baldamus Reinhard Kirmse 《无机化学与普通化学杂志》2004,630(15):2677-2686
Synthesis, Structures, NMR and EPR Investigations on Transition Metal Complexes of monofluorosubstituted Acylselenourea Ligands The syntheses and the structures of the ligand N, N‐diethyl‐N′‐(2‐fluoro)benzoylselenourea HEt2mfbsu and the complexes [Ni(Et2mfbsu)2] and [Zn(Et2mfbsu)2] as well as of the ligand N, N‐diisobutyl‐N′‐(2‐fluoro)benzoylselenourea HBui2mfbsu and the complexes [NiII(Bui2mfbsu)2] and [PdII(Bui2mfbsu)2] are reported. The ligands coordinate bidendately forming bischelates. The PdII and NiII complexes are cis coordinated; in [ZnII(Et2mfbsu)2] the ligands are tetrahedrally arranged. The structure of the also obtained bis[diisobutylamino‐(2‐fluorobenzoylimino)methyl]diselenide is reported. The CuII complexes of both selenourea ligands could not be isolated. They were obtained as oils. Their EPR spectra, however, confirm the presence of CuII bischelates unambiguously. Detailed NMR investigations ‐ 1H‐, 13C‐ and 19F‐COSY, HMBC and HMQC ‐ on [MII(Et2mfbsu)2] (M = NiII, ZnII) allow an exact assignment of all signals to the magnetically active nuclei of the complexes. 相似文献
11.
Xiao‐Min Hao Gang Chen Chang‐Sheng Gu Ji‐Wei Liu 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(7):712-714
In the title coordination polymer, {[Cd(C6H8O4S)(C13H14N2)]·H2O}n, the CdII atom displays a distorted octahedral coordination, formed by three carboxylate O atoms and one S atom from three different 3,3′‐thiodipropionate ligands, and two N atoms from two different 4,4′‐(propane‐1,3‐diyl)dipyridine ligands. The CdII centres are bridged through carboxylate O atoms of 3,3′‐thiodipropionate ligands and through N atoms of 4,4′‐(propane‐1,3‐diyl)dipyridine ligands to form two different one‐dimensional chains, which intersect to form a two‐dimensional layer. These two‐dimensional layers are linked by S atoms of 3,3′‐thiodipropionate ligands from adjacent layers to form a three‐dimensional network. 相似文献
12.
Dr. Bhupendra Goswami Dr. Thomas J. Feuerstein Dr. Ravi Yadav Dr. Ralf Köppe Dr. Sergei Lebedkin Prof. Dr. Manfred M. Kappes Prof. Dr. Peter W. Roesky 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(13):4401-4411
The synthesis of calcium complexes ligated by three different chiral iminophosphonamide ligands, L- H ( L =[Ph2P{N(R)CH(CH3)Ph}2]), L′ -H ( L′ =[Ph2P{NDipp}{N(R)CH(CH3)Ph}]), (Dipp=2,6-iPr2C6H3), and L′′ -H ( L′′ =[Ph2P{N(R)CH(CH3)naph}2]), (naph=naphthyl) is presented. The resulting structures [ L 2Ca], [ L′ 2Ca], and [ L′′ 2Ca] represent the first examples of enantiopure homoleptic calcium complexes based on this type of ligands. The calcium complexes show blue–green photoluminescence (PL) in the solid state, which is especially bright at low temperatures. Whereas the emission of [ L′′ 2Ca] is assigned to the fluorescence of naphthyl groups, the PL of [ L 2Ca] and [ L′ 2Ca] is contributed by long-lived phosphorescence and thermally activated delayed fluorescence (TADF), with a strong variation of the PL lifetimes over the temperature range of 5–295 K. Furthermore, an excellent catalytic activity was found for these complexes in hydroboration of ketones at room temperature, although no enantioselectivity was achieved. 相似文献
13.
Yongfeng Yang Tao Li Yanmei Chen 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(10):903-907
The title compound, poly[[diaqua‐1κ2O‐tetrakis(μ3‐pyridine‐2,3‐dicarboxylato)‐2:1:2′κ10N,O2:O2′,O3:O3′;2:1:2′κ8O3:O3′:N,O2‐diiron(III)strontium(II)] dihydrate], {[Fe2Sr(C7H3O4)4(H2O)2]·2H2O}n, which has triclinic (P) symmetry, was prepared by the reaction of pyridine‐2,3‐dicarboxylic acid, SrCl2·6H2O and Fe(OAc)2(OH) (OAc is acetate) in the presence of imidazole in water at 363 K. In the crystal structure, the pyridine‐2,3‐dicarboxylate (pydc2−) ligand exhibits μ3‐η1,η1:η1:η1 and μ3‐η1,η1:η1,η1:η1 coordination modes, bridging two FeIII cations and one SrII cation. The SrII cation, which is located on an inversion centre, is eight‐coordinated by six O atoms of four pydc2− ligands and two water molecules. The coordination geometry of the SrII cation can be best described as distorted dodecahedral. The FeIII cation is six‐coordinated by O and N atoms of four pydc2− ligands in a slightly distorted octahedral geometry. Each FeIII cation bridges two neighbouring FeIII cations to form a one‐dimensional [Fe2(pydc)4]n chain. The chains are connected by SrII cations to form a three‐dimensional framework. The topology type of this framework is tfj . The structure displays O—H...O and C—H...O hydrogen bonding. 相似文献
14.
En‐Cui Yang Pei‐Xia Dai Xiu‐Guang Wang Bin Ding Xiao‐Jun Zhao Prof. Dr. 《无机化学与普通化学杂志》2007,633(4):615-620
To survey the influence of aza‐aromatic co‐ligands on the structure of Cadmium(II) sulfonates, three Cd(II) complexes with mixed‐ligand, [CdII(ANS)2(phen)2] ( 1 ), [CdII(ANS)2(2,2′‐bipy)2] ( 2 ) and [CdII(ANS)2(4,4′‐bipy)2]n ( 3 ) (ANS = 2‐aminonaphthalene‐1‐sulfonate; phen = 1,10‐phenanthroline; 2,2′‐bipy = 2,2′‐bipyridine; 4,4′‐bipy = 4,4′‐bipyridine) were synthesized by hydrothermal methods and structurally characterized by elemental analyses, IR spectra, and single crystal X‐ray diffraction. Of the three complexes, ANS consistently coordinates to Cd2+ ion as a monodentate ligand. While phen in 1 and 2,2′‐bipy in 2 act as N,N‐bidentate chelating ligands, leading to the formation of a discrete mononuclear unit; 4,4′‐bipy in 3 bridges two CdII atoms in bis‐monodentate fashion to produce a 2‐D layered network, suggesting that the conjugate skeleton and the binding site of the co‐ligands have a moderate effect on molecular structure, crystal stacking pattern, and intramolecular weak interactions. In addition, the three complexes exhibit similar luminescent emissions originate from the transitions between the energy levels of sulfonate anions. 相似文献
15.
Dr. Jean‐François Lefebvre Dr. Mamadou Lo Dr. Jean‐Paul Gisselbrecht Dr. Olivier Coulembier Dr. Sébastien Clément Dr. Sébastien Richeter 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(46):15652-15660
We report herein a detailed study of the use of porphyrins fused to imidazolium salts as precursors of N‐heterocyclic carbene ligands 1 M . Rhodium(I) complexes 6 M – 9 M were prepared by using 1 M ligands with different metal cations in the inner core of the porphyrin (M=NiII, ZnII, MnIII, AlIII, 2H). The electronic properties of the corresponding N‐heterocyclic carbene ligands were investigated by monitoring the spectroscopic changes occurring in the cod and CO ancillary ligands of [( 1 M )Rh(cod)Cl] and [( 1 M )Rh(CO)2Cl] complexes (cod=1,5‐cyclooctadiene). Porphyrin–NHC ligands 1 M with a trivalent metal cation such as MnIII and AlIII are overall poorer electron donors than porphyrin–NHC ligands with no metal cation or incorporating a divalent metal cation such as NiII and ZnII. Imidazolium salts 3 M (M=Ni, Zn, Mn, 2H) have also been used as NHC precursors to catalyze the ring‐opening polymerization of L ‐lactide. The results clearly show that the inner metal of the porphyrin has an important effect on the reactivity of the outer carbene. 相似文献
16.
The axial halogen atoms as well as the equatorial η2-C2H4 and σ,σ′-N,N′ chelate bonded t-BuNCHCHNt-Bu ligands in pentacoordinate [PtCl2(η2-C2H4)(t-BuNCHCHNt-Bu)] can be displaced with retention of the trigonal bipyramidal structure. Halogen—halogen exchange is initiated by formation of an ionic intermediate [PtCl(η2-C2H4)(t-BuNCHCHNT-Bu)]Cl. The reversible exchange of the equation ligands with olefins or bidentate diimine or diamine ligands (NN) is proposed to proceed via pentacoordinate intermediates [PtCl2(η2-C2H4)(η2-olefin)(t-BuNCHCHNt-Bu)] and [PtCl2(η2-C2H4)(t-BuNCHCHNt-Bu)(N-N)], respectively in which the α-diimine is σ-N monodentate bonded. Selective coodination of cis-olefins (maleic anhydride, dimethylmalonate, methylacrylate or acrolein) has been observed. Some relevant 1H and 13C NMR data for the novel pentacoordinate PtII-olefin complexes are given. 相似文献
17.
Dr. Weiyin Yi Jie Zhang Prof. Dr. Fangjun Zhang Yin Zhang Dr. Zhenxia Chen Prof. Dr. Xigeng Zhou 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(36):11975-11983
A series of unusual chemical‐bond transformations were observed in the reactions of high active yttrium? dialkyl complexes with unsaturated small molecules. The reaction of scorpionate‐anchored yttrium? dibenzyl complex [TpMe2Y(CH2Ph)2(thf)] ( 1 , TpMe2=tri(3,5‐dimethylpyrazolyl)borate) with phenyl isothiocyanate led to C?S bond cleavage to give a cubane‐type yttrium–sulfur cluster, {TpMe2Y(μ3‐S)}4 ( 2 ), accompanied by the elimination of PhN?C(CH2Ph)2. However, compound 1 reacted with phenyl isocyanate to afford a C(sp3)? H activation product, [TpMe2Y(thf){μ‐η1:η3‐OC(CHPh)NPh}{μ‐η3:η2‐OC(CHPh)NPh}YTpMe2] ( 3 ). Moreover, compound 1 reacted with phenylacetonitrile at room temperature to produce γ‐deprotonation product [(TpMe2)2Y]+[TpMe2Y(N=C?CHPh)3]? ( 6 ), in which the newly formed N?C?CHPh ligands bound to the metal through the terminal nitrogen atoms. When this reaction was carried out in toluene at 120 °C, it gave a tandem γ‐deprotonation/insertion/partial‐TpMe2‐degradation product, [(TpMe2Y)2(μ‐Pz)2{μ‐η1:η3‐NC(CH2Ph)CHPh}] ( 7 , Pz=3,5‐dimethylpyrazolyl). 相似文献
18.
Xiu‐Yan Wang Jia‐Jun Wang Seik Weng Ng 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(12):m401-m404
The ZnII compounds, μ‐4,4′‐ethylenedibenzoato‐bis[acetatoaqua(dipyrido[3,2‐a:2′,3′‐c]phenazine)zinc(II)] dihydrate, [Zn2(C2H3O2)2(C16H10O4)(C18H10N4)2(H2O)2]·2H2O, (I), and catena‐poly[[[aqua(pyrazino[2,3‐f][1,10]phenanthroline)zinc(II)]‐μ‐4,4′‐ethylenedibenzoato] N,N‐dimethylformamide hemisolvate], {[Zn(C16H10O4)(C14H8N4)(H2O)]·0.5C3H7NO}n, (II), display very different structures because of the influence of the N‐donor chelating ligands. In (I), the coordination geometry of each ZnII centre is distorted octahedral, involving two N atoms from one dipyrido[3,2‐a:2′,3′‐c]phenazine (L1) ligand, and four O atoms from one bis‐chelating acetate anion, one bridging 4,4′‐ethylenedibenzoate (bpea) ligand and one water molecule. Adjacent ZnII atoms are bridged by one bpea ligand to form a dinuclear complex, and the dinuclear species is centrosymmetric. Two types of π–π interactions between neighbouring dinuclear species have been found: one is between the L1 ligands, and the second is between the L1 and bpea ligands. In this way, an interesting two‐dimensional supramolecular layer is formed. The layers are further linked by O—H...O and O—H...N hydrogen bonds, generating a three‐dimensional supramolecular network. In (II), each ZnII atom is square‐pyramidally coordinated by two N atoms from one pyrazino[2,3‐f][1,10]phenanthroline ligand, three O atoms from two different bpea ligands and one water molecule. The two bpea dianions are situated across inversion centres. The bpea dianions bridge neighbouring ZnII centres, giving a one‐dimensional chain structure in the ab plane. As in (I), two types of π–π interactions between neighbouring chains complete a three‐dimensional supramolecular structure. The results indicate that the structures of the N‐donor chelating ligands are the dominant factors determining the final supramolecular structures of the two compounds. 相似文献
19.
Synthesis and Structures of the Zinc‐ and Cadmium‐N‐Acylthiourea Complexes The synthesis and crystal structures of the N,N‐Diisobutyl‐N′‐benzoylthiourea complexes [Zn(Bui2btu)2] and [Cd(Bui2btu)2(HBui2btu)] are reported. The complexes of ZnII and CdII have different molecular structures. Whereas ZnII forms a bischelate with tetrahedral coordination, three ligands coordinate in a trigonal‐bipyramidal manner in the CdII complex. 相似文献
20.
Ya-Hui Liu Li-Ping Lu Miao-Li Zhu Feng Su 《Acta Crystallographica. Section C, Structural Chemistry》2016,72(4):358-362
Coordination polymers (CPs) built by coordination bonds between metal ions/clusters and multidentate organic ligands exhibit fascinating structural topologies and potential applications as functional solid materials. The title coordination polymer, poly[diaquabis(μ4‐biphenyl‐3,4′,5‐tricarboxylato‐κ4O3:O3′:O4′:O5)tris[μ2‐1,4‐bis(1H‐imidazol‐1‐yl)benzene‐κ2N3:N3′]dicopper(II)dicopper(I)], [CuII2CuI2(C15H7O6)2(C12H10N4)3(H2O)2]n, was crystallized from a mixture of biphenyl‐3,4′,5‐tricarboxylic acid (H3bpt), 1,4‐bis(1H‐imidazol‐1‐yl)benzene (1,4‐bib) and copper(II) chloride in a water–CH3CN mixture under solvothermal reaction conditions. The asymmetric unit consists of two crystallographically independent Cu atoms, one of which is CuII, while the other has been reduced to the CuI ion. The CuII centre is pentacoordinated by three O atoms from three bpt3− ligands, one N atom from a 1,4‐bib ligand and one O atom from a coordinated water molecule, and the coordination geometry can be described as distorted trigonal bipyramidal. The CuI atom exhibits a T‐shaped geometry (CuN2O) coordinated by one O atom from a bpt3− ligand and two N atoms from two 1,4‐bib ligands. The CuII atoms are extended by bpt3− and 1,4‐bib linkers to generate a two‐dimensional network, while the CuI atoms are linked by 1,4‐bib ligands, forming one‐dimensional chains along the [20] direction. In addition, the completely deprotonated μ4‐η1:η1:η1:η1 bpt3− ligands bridge one CuI and three CuII cations along the a (or [100]) direction to form a three‐dimensional framework with a (103)2(10)2(42.6.102.12)2(42.6.82.10)2(8) topology via a 2,2,3,4,4‐connected net. An investigation of the magnetic properties indicated a very weak ferromagnetic behaviour. 相似文献