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1.
Selenoquinones Stabilized by Ruthenium(II) Arene Complexes: Synthesis,Structure, and Cytotoxicity
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Dr. Julien Dubarle‐Offner Catherine M. Clavel Geoffrey Gontard Prof. Paul J. Dyson Dr. Hani Amouri 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(19):5795-5801
A new series of monoselenoquinone and diselenoquinone π complexes, [(η6‐p‐cymene)Ru(η4‐C6R4SeE)] (R=H, E=Se ( 6 ); R=CH3, E=Se ( 7 ); R=H, E=O ( 8 )), as well as selenolate π complexes [(η6‐p‐cymene)Ru(η5‐C6H3R2Se)][SbF6] (R=H ( 9 ); R=CH3 ( 10 )), stabilized by arene ruthenium moieties were prepared in good yields through nucleophilic substitution reactions from dichlorinated‐arene and hydroxymonochlorinated‐arene ruthenium complexes [(η6‐p‐cymene)Ru(C6R4XCl)][SbF6]2 (R=H, X=Cl ( 1 ); R=CH3, X=Cl ( 2 ); R=H, X=OH ( 3 )) as well as the monochlorinated π complexes [(η6‐p‐cymene)Ru(η5‐C6H3R2Cl)][SbF6]2 (R=H ( 4 ); R=CH3 ( 5 )). The X‐ray crystallographic structures of two of the compounds, [(η6‐p‐cymene)Ru(η4‐C6Me4Se2)] ( 7 ) and [(η6‐p‐cymene)Ru(η4‐C6H4SeO)] ( 8 ), were determined. The structures confirm the identity of the target compounds and ascertain the coordination mode of these unprecedented ruthenium π complexes of selenoquinones. Furthermore, these new compounds display relevant cytotoxic properties towards human ovarian cancer cells. 相似文献
2.
Otilia Mó Al Mokhtar Lamsabhi Manuel Yáñez Gavin S. Heverly‐Coulson Russell J. Boyd 《Journal of computational chemistry》2013,34(29):2537-2547
The reactions of XSeSX, XSeSY, and YSeSX (X, Y = CH3, NH2, OH, F) with F? and CN? nucleophiles have been investigated by means of B3PW91/6‐311+G(2df,p) and G4 calculations. In systems where the two substituents are not identical (XSeSY), the more stable of the two possible isomers corresponds to those in which the most electronegative substituent is attached to Se. Nucleophilic attack takes place at Se, independent of the nature of the nucleophile, with the only exception being XSeSF (X = CH3, NH2, OH), in which case the attack occurs at S. In agreement with recent results for disulfide and diselenide linkages, the mechanisms leading to Se—S bond cleavage are not always the more favorable ones because for highly electronegative substituents the most favorable process is fission of the chalcogen‐substituent bond. These dissimilarities in the observed reactivity pattern as a function of the electronegativity of the substituents are due to the fact that the σ‐type Se—S antibonding orbital, which for low‐electronegative substituents is the lowest unnoccupied molecular orbital (LUMO), becomes strongly destabilized when the electronegativity of the substituent increases, and is replaced by an antibonding π‐type Se‐X (or S‐X) orbital. In contrast, however, with what has been found for disulfide and diselenide derivatives, the observed reactivity does not change with the nature of the nucleophile. The activation strain model provides interesting insight into these processes, showing that in most cases the activation barriers are the consequence of subtle differences in the strain or in the interaction energies. © 2013 Wiley Periodicals, Inc. 相似文献
3.
The seleno‐bis (S‐glutathionyl) arsinium ion, [(GS)2AsSe]?, which can be synthesized from arsenite, selenite and glutathione (GSH) at physiological pH, fundamentally links the mammalian metabolism of arsenite with that of selenite and is potentially involved in the chronic toxicity/carcinogenicity of inorganic arsenic. A mammalian metabolite of inorganic arsenic, dimethylarsinic acid, reacts with selenite and GSH in a similar manner to form the dimethyldiselenoarsinate anion, [(CH3)2As(Se)2]?. Since dimethylarsinic acid is an environmentally abundant arsenic compound that could interfere with the mammalian metabolism of the essential trace element selenium via the in vivo formation of [(CH3)2As(Se)2]?, a chromatographic method was developed to rapidly identify this compound in aqueous samples. Using an inductively coupled plasma atomic emission spectrometer (ICP‐AES) as the simultaneous arsenic‐ and selenium‐specific detector, the chromatographic retention behaviour of [(CH3)2As(Se)2]? was investigated on styrene–divinylbenzene‐based high‐performance liquid chromatography (HPLC) columns. With a Hamilton PRP‐1 column as the stationary phase (250 × 4.1 mm ID, equipped with a guard column) and a phosphate‐buffered saline buffer (0.01 mol dm?3, pH 7.4) as the mobile phase, [(CH3)2As(Se)2]? was identified in the column effluent according to its arsenic:selenium molar ratio of 1 : 2. With this stationary phase/mobile phase combination, [(CH3)2As(Se)2]? was baseline‐separated from arsenite, selenite, dimethylarsinate, methylarsonate and low molecular weight thiols (GSH, oxidized GSH) that are frequently encountered in biological samples. Thus, the HPLC–ICP‐AES method developed should be useful for rapid identification and quantification of [(CH3)2As(Se)2]? in biological fluids. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
4.
An ion‐neutral complex (INC)‐mediated hydride transfer reaction was observed in the fragmentation of protonated N‐benzylpiperidines and protonated N‐benzylpiperazines in electrospray ionization mass spectrometry. Upon protonation at the nitrogen atom, these compounds initially dissociated to an INC consisting of [RC6H4CH2]+ (R = substituent) and piperidine or piperazine. Although this INC was unstable, it did exist and was supported by both experiments and density functional theory (DFT) calculations. In the subsequent fragmentation, hydride transfer from the neutral partner to the cation species competed with the direct separation. The distribution of the two corresponding product ions was found to depend on the stabilization energy of this INC, and it was also approved by the study of substituent effects. For monosubstituted N‐benzylpiperidines, strong electron‐donating substituents favored the formation of [RC6H4CH2]+, whereas strong electron‐withdrawing substituents favored the competing hydride transfer reaction leading to a loss of toluene. The logarithmic values of the abundance ratios of the two ions were well correlated with the nature of the substituents, or rather, the stabilization energy of this INC. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
5.
Stable ‐ESiMe3 Complexes of CuI and AgI (E=S,Se) with NHCs: Synthons in Ternary Nanocluster Assembly
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Mahmood Azizpoor Fard Tetyana I. Levchenko Carolyn Cadogan William J. Humenny Prof. Dr. John F. Corrigan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(13):4543-4550
As a part of efforts to prepare new “metallachalcogenolate” precursors and develop their chemistry for the formation of ternary mixed‐metal chalcogenide nanoclusters, two sets of thermally stable, N‐heterocyclic carbene metal–chalcogenolate complexes of the general formula [(IPr)Ag?ESiMe3] (IPr=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene; E=S, 1 ; Se, 2 ) and [(iPr2‐bimy)Cu?ESiMe3]2 (iPr2‐bimy=1,3‐diisopropylbenzimidazolin‐2‐ylidene; E=S, 4 ; Se, 5 ) are reported. These are prepared from the reaction between the corresponding carbene metal acetate, [(IPr)AgOAc] and [(iPr‐bimy)CuOAc] respectively, and E(SiMe3)2 at low temperature. The reaction of [(IPr)Ag?ESiMe3] 1 with mercury(II) acetate affords the heterometallic complex [{(IPr)AgS}2Hg] 3 containing two (IPr)Ag?S? fragments bonded to a central HgII, representing a mixed mercury–silver sulfide complex. The reaction of [(iPr2‐bimy)Cu‐SSiMe3]2, which contains a smaller N‐heterocyclic‐carbene, with mercuric(II) acetate affords the high nuclearity cluster, [(iPr2‐bimy)6Cu10S8Hg3] 6 . The new N‐heterocyclic carbene metal–chalcogenolate complexes 1 , 2 , 4 , 5 and the ternary mixed‐metal chalcogenolate complex 3 and cluster 6 have been characterized by multinuclear NMR spectroscopy (1H and 13C), elemental analysis and single‐crystal X‐ray diffraction. 相似文献
6.
The novel thiodiphosphate, [Na(12‐crown‐4)2]2[P2S6] · CH3CN, bis[di(12‐crown‐4)sodium] hexathiodiphosphate(V) acetonitrile solvate ( 1 ) has been synthesized by the reaction of Na2[P2S6] with 12‐crown‐4 in dry acetonitrile. The title compound crystallizes in the tetragonal space group P42/mbc (no. 135), with a = 15.184(1) Å, c = 21.406(2) Å and Z = 4 and final R1 = 0.0671 and wR2 = 0.0809. The crystal structure is characterized by discrete sodium‐bound crown‐ether sandwich cations, [Na(12‐crown‐4)2]+ and [P2S6]2? ions with D2h symmetry. Sodium ion is coordinated by the eight oxygen atoms of two crown‐ether molecules to form a square antiprisma. Solvent molecules of CH3CN are statistically disordered. Distances and angles of the [P2S6]2? unit are similar to those in [K(18‐crown‐6)]2 [P2S6] · 2 CH3CN, and in K2[P2S6] and Cs2[P2S6]. The FT‐Raman and FT‐IR spectrum of the title compound has been recorded and interpreted, especially with respect to the P2S6 group and in comparison to the few known metal hexathiodiphosphates(V). 相似文献
7.
《应用有机金属化学》2017,31(11)
A series of new cyclopentadienyl molybdenum compounds bearing substituted phenanthroline ligands [(η5‐C5H4CH2C6H4X‐4)Mo(CO)2(N,NL)][BF4] (X = F, Cl, Br; N,NL = phen, 5‐NH2‐phen, 4,7‐Ph2‐phen) was prepared and characterized using infrared and NMR spectroscopies. Crystal structures of [(η5‐C5H4CH2C6H4F‐4)Mo(CO)2(NCMe)2][BF4], [(η5‐C5H4CH2C6H4X‐4)Mo(CO)2(phen)][BF4] (X = F, Cl, Br) and [(η5‐C5H4CH2C6H4Cl‐4)Mo(CO)2(4,7‐Ph2‐phen)][BF4]⋅(4,7‐Ph2‐phen)⋅HBF4 were determined using X‐ray diffraction analysis. Biological studies revealed a strong cytotoxic effect of the chelating ligands. Although the cytostatic effect of the halogen in the side chain of the cyclopentadienyl ring is negligible, it could be used for future post‐modification of these types of cytotoxic active molybdenum‐based compounds. 相似文献
8.
Niklas Rinn Dr. Jens P. Eußner Willy Kaschuba Dr. Xiulan Xie Prof. Dr. Stefanie Dehnen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(9):3094-3104
Reactions of R1SnCl3 (R1=CMe2CH2C(O)Me) with (SiMe3)2Se yield a series of organo‐functionalized tin selenide clusters, [(SnR1)2SeCl4] ( 1 ), [(SnR1)2Se2Cl2] ( 2 ), [(SnR1)3Se4Cl] ( 3 ), and [(SnR1)4Se6] ( 4 ), depending on the solvent and ratio of the reactants used. NMR experiments clearly suggest a stepwise formation of 1 through 4 by subsequent condensation steps with the concomitant release of Me3SiCl. Furthermore, addition of hydrazines to the keto‐functionalized clusters leads to the formation of hydrazone derivatives, [(Sn2(μ‐R3)(μ‐Se)Cl4] ( 5 , R3=[CMe2CH2CMe(NH)]2), [(SnR2)3Se4Cl] ( 6 , R2=CMe2CH2C(NNH2)Me), [(SnR4)3Se4][SnCl3] ( 7 , R4=CMe2CH2C(NNHPh)Me), [(SnR2)4Se6] ( 8 ), and [(SnR4)4Se6] ( 9 ). Upon treatment of 4 with [Cu(PPh3)3Cl] and excess (SiMe3)2Se, the cluster fragments to form [(R1Sn)2Se2(CuPPh3)2Se2] ( 10 ), the first discrete Sn/Se/Cu cluster compound reported in the literature. The derivatization reactions indicate fundamental differences between organotin sulfide and organotin selenide chemistry. 相似文献
9.
《Journal of organometallic chemistry》1986,303(2):167-178
The electron impact mass spectra of the [1]titanocenophane dihalides (CH3)2Si(C5H4)2TiX2 (X = Cl, Br, I) and of [(CH3)3EC5H4]2TiCl2 complexes (E = C, Si, Ge) are described. The fragmentation of the compounds is highly influenced by the substituents at the cyclopentadienyl rings and shows several interesting rearrangements, e.g. elimination of (CH3)2SiX2 in the case of the [1]titanocenophane complexes. 相似文献
10.
Simon H. Stelzig Matthias Tamm Robert M. Waymouth 《Journal of polymer science. Part A, Polymer chemistry》2008,46(18):6064-6070
Monocyclopentadienyl titanium imidazolin‐2‐iminato complexes [Cp′Ti(L)X2] 1a (Cp′ = cyclopentadienyl, L = 1,3‐di‐tert‐butylimidazolin‐2‐imide, X = Cl), 1b (X = CH3); 2 (Cp′ = cyclopentadienyl, L = 1,3‐diisopropylimidazolin‐2‐imide, X = Cl); 3 (Cp′ = tert‐butylcyclopentadienyl, L = 1,3‐di‐tert‐butylimidazolin‐2‐imide, X = Cl), upon activation with methylaluminoxane (MAO) were active for the polymerization of ethylene and propylene and the copolymerization of ethylene and 1‐hexene. Catalysts derived from imidazolin‐2‐iminato tropidinyl titanium complex 4 = [(Trop)Ti(L)Cl2] (Trop = tropidinyl, L = 1,3‐di‐tert‐butylimidazolin‐2‐imide) were much less active. Narrow polydispersities were observed for ethylene and propylene polymerization, but the copolymerization of ethylene/hexene led to bimodal molecular weight distributions. The productivity of catalysts derived from the dialkyl complex 1b activated with [Ph3C][B(C6F5)4] or B(C6F5)3 were less active for ethylene/hexene copolymerization but yielded ethylene/hexene copolymers of narrower molecular weight distributions than those derived from 1a/MAO. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6064–6070, 2008 相似文献
11.
Runhai Chen Guorui Qin Shihui Li Alison J. Edwards Ross O. Piltz Iker Del Rosal Laurent Maron Dongmei Cui Jianhua Cheng 《Angewandte Chemie (International ed. in English)》2020,59(28):11250-11255
Hydrogenolysis of alkyl‐substituted cyclopentadienyl (CpR) ligated thorium tribenzyl complexes [(CpR)Th(p‐CH2‐C6H4‐Me)3] ( 1 – 6 ) afforded the first examples of molecular thorium trihydrido complexes [(CpR)Th(μ‐H)3]n (CpR=C5H2(tBu)3 or C5H2(SiMe3)3, n=5; C5Me4SiMe3, n=6; C5Me5, n=7; C5Me4H, n=8; 7 – 10 and 12 ) and [(Cp#)12Th13H40] (Cp#=C5H4SiMe3; 13 ). The nuclearity of the metal hydride clusters depends on the steric profile of the cyclopentadienyl ligands. The hydrogenolysis intermediate, tetra‐nuclear octahydrido thorium dibenzylidene complex [(Cpttt)Th(μ‐H)2]4(μ‐p‐CH‐C6H4‐Me)2 (Cpttt=C5H2(tBu)3) ( 11 ) was also isolated. All of the complexes were characterized by NMR spectroscopy and single‐crystal X‐ray analysis. Hydride positions in [(CpMe4)Th(μ‐H)3]8 (CpMe4=C5Me4H) were further precisely confirmed by single‐crystal neutron diffraction. DFT calculations strengthen the experimental assignment of the hydride positions in the complexes 7 to 12 . 相似文献
12.
Influence of Cyclopentadienyl Ring‐Tilt on Electron‐Transfer Reactions: Redox‐Induced Reactivity of Strained [2] and [3]Ruthenocenophanes
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Dr. Andrew D. Russell Prof. Joe B. Gilroy Prof. Kevin Lam Dr. Mairi F. Haddow Prof. Jeremy N. Harvey Prof. William E. Geiger Prof. Ian Manners 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(49):16216-16227
In contrast to ruthenocene [Ru(η5‐C5H5)2] and dimethylruthenocene [Ru(η5‐C5H4Me)2] ( 7 ), chemical oxidation of highly strained, ring‐tilted [2]ruthenocenophane [Ru(η5‐C5H4)2(CH2)2] ( 5 ) and slightly strained [3]ruthenocenophane [Ru(η5‐C5H4)2(CH2)3] ( 6 ) with cationic oxidants containing the non‐coordinating [B(C6F5)4]? anion was found to afford stable and isolable metal?metal bonded dicationic dimer salts [Ru(η5‐C5H4)2(CH2)2]2[B(C6F5)4]2 ( 8 ) and [Ru(η5‐C5H4)2(CH2)3]2[B(C6F5)4]2 ( 17 ), respectively. Cyclic voltammetry and DFT studies indicated that the oxidation potential, propensity for dimerization, and strength of the resulting Ru?Ru bond is strongly dependent on the degree of tilt present in 5 and 6 and thereby degree of exposure of the Ru center. Cleavage of the Ru?Ru bond in 8 was achieved through reaction with the radical source [(CH3)2NC(S)S?SC(S)N(CH3)2] (thiram), affording unusual dimer [(CH3)2NCS2Ru(η5‐C5H4)(η3‐C5H4)C2H4]2[B(C6F5)4]2 ( 9 ) through a haptotropic η5–η3 ring‐slippage followed by an apparent [2+2] cyclodimerization of the cyclopentadienyl ligand. Analogs of possible intermediates in the reaction pathway [C6H5ERu(η5‐C5H4)2C2H4][B(C6F5)4] [E=S ( 15 ) or Se ( 16 )] were synthesized through reaction of 8 with C6H5E?EC6H5 (E=S or Se). 相似文献
13.
The asymmetric reduction of benzophenones p-X-C6H4-CO-C6H5 (X = CH3, OCH3, Br, CF3) and p-CF3-C6H4-CO-C6H4-p'-Z (Z = CH3, Br) by chiral Grignard reagents p-Y-C6H4-CH(C2H5)CH2MgCl (Y = OCH3, CF3) gives benzhydrols of optical purities which can reach 37%. The absolute configuration of the alcohol depends on the nature of substituents. The substituent effect is discussed through donor-acceptor interactions between the aromatic nuclei in the diastereoisomeric transition states. 相似文献
14.
Sangeeta Yadav Ouissam ElBakouri Kjell Jorner Hui Tong Christian Dahlstrand Miquel Sol Henrik Ottosson 《化学:亚洲杂志》2019,14(10):1870-1878
Due to the reversal in electron counts for aromaticity and antiaromaticity in the closed‐shell singlet state (normally ground state, S0) and lowest ππ* triplet state (T1 or T0), as given by Hückel's and Baird's rules, respectively, fulvenes are influenced by their substituents in the opposite manner in the T1 and S0 states. This effect is caused by a reversal in the dipole moment when going from S0 to T1 as fulvenes adapt to the difference in electron counts for aromaticity in various states; they are aromatic chameleons. Thus, a substituent pattern that enhances (reduces) fulvene aromaticity in S0 reduces (enhances) aromaticity in T1, allowing for rationalizations of the triplet state energies (ET) of substituted fulvenes. Through quantum chemical calculations, we now assess which substituents and which positions on the pentafulvene core are the most powerful for designing compounds with low or inverted ET. As a means to increase the π‐electron withdrawing capacity of cyano groups, we found that protonation at the cyano N atoms of 6,6‐dicyanopentafulvenes can be a route to on‐demand formation of a fulvenium dication with a triplet ground state (T0). The five‐membered ring of this species is markedly Baird‐aromatic, although less than the cyclopentadienyl cation known to have a Baird‐aromatic T0 state. 相似文献
15.
The New Mixed Valent Chalcogenoindates MIn7X9 (M = Rb, Cs; X = S, Se): Structural Chemistry, X‐Ray and HRTEM Investigations Systematic X‐ray and HRTEM investigations on the ternary systems alkali metal (or thallium)–indium–chalcogen proved the existence of mixed valent solids with the simultaneous occurrence of indium species in different states of oxidation. Additionally to the earlier described solids MIn5S7 (M: Na, K, Tl: isotypic to InIn5S7 = In6S7 and TlIn5S7) and KIn5S6 (isotyp to TlIn5S6) in the actual work we present with MIn7X9 (M: Rb, Cs; X: S, Se) a new structure type which also contains indium in the states of oxidation +3 and +2. The formal state of oxidation In2+ corresponds to (In2)4+ ions. A reasonable ionic formulation of these structures is given by: MIn5S7 = M+ 3[In3+] [(In2)4+] 7[S2–] (M = Na, K, Tl), MIn5S6 = M+ [In3+] 2[(In2)4+] 6[S2–] (M = K, Tl), MIn7X9 = M+ 3[In3+] 2[(In2)4+] 9[S2–]. The three structure types show common two dimensional structure elements which contain ethane analogous In2X6 units and cis and trans edge sharing double octahedron chains. The main interest of this work is a crystalchemical discussion taking into account the new compounds MIn7X9 and the results of special HRTEM investigations on MIn7X9. The HRTEM investigations aim on the identification and subsequent preparation of new phases which initially might be visible as nano size crystals or inclusions in the HRTEM only. 相似文献
16.
Herbert Schumann Esther C. E. Rosenthal Jrg Demtschuk Stefan Mühle 《无机化学与普通化学杂志》2000,626(10):2161-2166
Organometallic Compounds of the Lanthanides. 139 Mixed Sandwich Complexes of the 4 f Elements: Enantiomerically Pure Cyclooctatetraenyl Cyclopentadienyl Complexes of Samarium and Lutetium with Donor‐Functionalized Cyclopentadienyl Ligands The reactions of [K{(S)‐C5H4CH2CH(Me)OMe}], [K{(S)‐C5H4CH2CH(Me)NMe2}] and [K{(S)‐C5H4CH(Ph)CH2NMe2}] with the cyclooctatetraenyl lanthanide chlorides [(η8‐C8H8)Ln(μ‐Cl)(THF)]2 (Ln = Sm, Lu) yield the mixed cyclooctatetraenyl cyclopentadienyl lanthanide complexes [(η8‐C8H8)Sm{(S)‐η5 : η1‐C5H4CH2CH(Me)OMe}] ( 1 a ), [(η8‐C8H8)Ln{(S)‐η5 : η1‐C5H4CH2CH(Me)NMe2}] (Ln = Sm ( 2 a ), Lu ( 2 b )) and [(η8‐C8H8)Ln{(S)‐η5 : η1‐C5H4CH(Ph)CH2NMe2}] (Ln = Sm ( 3 a ), Lu ( 3 b )). For comparison, the achiral compounds [(η8‐C8H8)Ln{η5 : η1‐C5H4CH2CH2NMe2}] (Ln = Sm ( 4 a ), Lu ( 4 b )) are synthesized in an analogous manner. 1H‐, 13C‐NMR‐, and mass spectra of all new compounds as well as the X‐ray crystal structures of 3 b and 4 b are discussed. 相似文献
17.
Organotin–Oxido Cluster‐Based Multiferrocenyl Complexes Obtained by Hydrolysis of Ferrocenyl‐Functionalized Organotin Chlorides
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Zhiliang You Robert Möckel Jakob Bergunde Prof. Dr. Stefanie Dehnen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(42):13491-13496
Three organotin–oxido clusters were formed by hydrolysis of ferrocenyl‐functionalized organotin chloride precursors in the presence of NaEPh (E=S, Se). [RFcSnCl3?HCl] ( C ; RFc = CMe2CH2C(Me)?N?N?C(Me)Fc) and [SnCl6]2? formed {(RFcSnCl2)3[Sn(OH)6]}[SnCl3] ( 3 a ) and {(RFcSnCl2)3[Sn(OH)6]}[PhSeO3] ( 3 b ), bearing an unprecedented [Sn4O6] unit, in a one‐pot synthesis or stepwise through [(RFcSnCl2)2Se] ( 1 ) plus [(RFcSnCl2)SePh] ( 2 ). A one‐pot reaction starting out from FcSnCl3 gave [(FcSn)9(OH)6O8Cl5] ( 4 ), which represents the largest Fc‐decorated Sn/O cluster reported to date. 相似文献
18.
In the homopolymerisation of propene by the cyclopentadienyl‐amide titanium catalyst systems [η5,η1‐C5H4(CH2)2NR]TiCl2/MAO and [η5,η1‐C5H4(CH2)2NR]Ti(CH2Ph)2/B(C6F5)3 (R = tBu, iPr, Me), the catalyst with the smallest substituent (Me) on the amido moiety consistently gives the highest polymer molecular weight. This differs from the trend usually observed in related catalysts with tetramethylcyclopentadienyl‐amide ancillary ligands, where larger amide substituents result in higher molecular weights. Based on the present information a hypothesis is formulated in which an increased cation‐anion interaction for the less sterically hindered catalyst is responsible for disfavouring chain transfer relative to chain growth. 相似文献
19.
Christoph Aubauer Konstatin Karaghiosoff Thomas M. Klaptke Gernot Kramer Axel Schulz Jan Weigand 《无机化学与普通化学杂志》2001,627(11):2547-2552
1,3‐Dipentafluorophenyl‐2,2,2,4,4,4‐hexazido‐1,3‐diaza‐2,4‐diphosphetidine ( 1 ) was synthesized by the reaction of [(C6F5)NPCl3]2 with trimethylsilyl azide in CH2Cl2 and characterized by multinuclear NMR and vibrational spectroscopy. The molecular structure of the compound was determined by single‐crystal X‐ray structure analysis. [(C6F5)NP(N3)3]2 crystallizes in the monoclinic space group P21/n with a = 9.6414(2), b = 7.4170(1) and c = 15.9447(4) Å, β = 94.4374(9)°, with 2 formula units per unit cell. The bond situation in [(C6F5)NP(N3)3]2 has been studied on the basis of NBO analysis. The antisymmetric stretching vibration of the azide groups is discussed. The structural diversity of 1 and 1,3‐diphenyl‐2,2,2,4,4,4‐hexazido‐1,3‐diaza‐2,4‐diphosphetidine in solution and in the solid state depending on the aryl substituent at the nitrogen atom is discussed. 相似文献
20.
Tetrafluorobo‐Synthesis and Deprotonation of a Phosphinomethylimidazolium Salt. On the π‐Electron Delocalization im Aminovinyl Phosphanes [1] The ylidic olefin 1, 3, 4, 5‐tetramethyl‐2‐methyleneimidazoline ( 1 , Im=CH2) reacts with chlorodiphenylphosphane to give the phosphane salt [(Im‐CH2)PPh2]Cl ( 6 ) from which the vinylphosphane Im=CHPPh2 ( 8 ) is obtained by deprotonation. 8 reacts with HBF4 etherate to give the tetrafluoroborate salt [(Im‐CH2)‐PPh2] BF4 ( 7 ). The crystal structures of 7 and 8 are determined and discussed. In 8 , π‐electron delocalisation is indicated both by structural data and temperature dependent n.m.r. spectroscopy 相似文献