CH4,CO2和O2制合成气反应中载体对Ni催化剂抗氧化性能的影响

在ＣＨ４、ＣＯ２ 催化氧化制合成气反应中, Ｎｉ／Ａｌ２Ｏ３ 催化剂在高温下生成ＮｉＡｌ２Ｏ４ 尖晶石,是导致催化剂失活的一个重要因素． 通过向载体（Ａｌ２Ｏ３）中添加各种氧化物, 使得催化剂的抗氧化性能得到改善． 并运用ＴＰＲ、ＸＲＤ对催化剂进行表征, 发现催化剂的抗氧化性顺序为： Ｎｉ／ＣａＯ－Ａｌ２Ｏ３ ＞ Ｎｉ／ＭｇＯ－Ａｌ２Ｏ３ ＞ Ｎｉ／ＣｅＯ２－Ａｌ２Ｏ３ ＞ Ｎｉ／Ｌａ２Ｏ３－Ａｌ２Ｏ３ ＞ Ｎｉ／Ｙ２Ｏ３－Ａｌ２Ｏ３ ＞ Ｎｉ／ＴｉＯ２－Ａｌ２Ｏ３＞ Ｎｉ／Ａｌ２Ｏ３＞ Ｎｉ／Ｆｅ２Ｏ３－Ａｌ２Ｏ３．     

若干镧系络合物的空间群

摘要 藉助模拟强度精修将九个镧系络合物晶体结构的空间群作了修正 .（ 1） NaN[Nd(DMSO)5(H2O)3]Cl3· 3H2O从 P1修正为 P;（ 2） Er(ClO4)3· 6(CH3)2NC(O)N(CH3)2从 P修正为 R;（ 3） Nd(O3SCF3)3· DMF· 6H2O从 P1修正为 R3m;(4)[NaNCCH3][Nd{S2CN(CH2CH3)2}4]从 P修正为 C 2/c;(5)[(CH3)2NCS2]3La· 2DMSO从 Cc修正为 C 2/c;（ 6） Yb(C9H7)2· 2THF从 Cc修正为 C 2/c;（ 7） [(C6H5)3Ge]2Yb· 4THF从 P21修正为 P 2;(8)TlPr(C36H44N4)2从 Pna2,修正为 Pnma;(9)[CuLaSm(C4O4)4(H2O)16]· 2H2O从 P2修正为 P2.（ 8）、（ 9）两个络合物结构从非心修正到有心时,不仅改进了键长与键角值,而且影响到分子结构特征的描述 .     

Evidence for strong tantalum-to-boron dative interactions in (silox)3Ta(BH3) and (silox)3Ta(eta2-B,Cl-BCl2Ph) (silox = tBu3SiO)1

Treatment of (silox)3Ta (1, silox = tBu3SiO) with BH3.THF and BCl2Ph afforded (silox)3Ta(BH3) (2) and (silox)3Ta(eta2-B,Cl-BCl2Ph) (3), which are both remarkably stable Ta(III) compounds. NMe3 and ethylene failed to remove BH3 from 2, and no indication of BH3 exchange with BH3.THF-d8 was noted via variable-temperature 1H NMR studies. Addition of BH3.THF to (silox)3TaH2 provided the borohydride-hydride (silox)3HTa(eta3-BH4) (5), and its thermolysis released H2 to generate 2. Exposure of 2 to D2 enabled the preparation of isotopologues (silox)3Ta(BH3-nDn) (n = 0, 2; 1, 2-D; 2, 2-D2; 3, 2-D3) for isotopic perturbation of chemical shift studies, but these failed to distinguish between "inverse adduct" (i.e., (silox)3Ta-->BH3) or (silox)3Ta(eta2-B,H-BH3) forms of 2. Computational models (RO)3Ta(BH3) (R = H, 2'; SiH3, 2SiH SiMe3, 2SiMe, and SitBu3, 2SiBu) were investigated to assess the relative importance of steric and electronic effects on structure and bonding. With small R, eta2-B,H structures were favored, but for 2SiMe and 2SiBu, the dative structure proved to be similar in energy. The electonic and vibrational features of both structure types were probed. The IR spectrum of 2 was best matched by the eta2-B,H conformer of 2SiBu. In related computations pertaining to 3, small R models favored the oxidative addition of a BCl bond, while with R = SitBu3 (3SiBu), an excellent match with its X-ray crystal structure revealed the critical steric influence of the silox ligands.     

Influence of support on resistance to carbon-deposition of catalyst for CH4, CO2 with O2 to synthesis gas

In the reaction of catalytic oxidation of CH4,CO2 with O2 to synthesis gas, carbon-deposition is an important factor for deactivation. By adding different oxides to Ni/AI2O3 catalyst, its resistance to carbon-deposition was improved. The experimental results indicate that the order of resistance to carbon-deposition is as follows: Ni/CaO-AI2O3>Ni/MgO-AI2O3>Ni/ TiO2-AI2O3>Ni/CeO2-AI2O3>Ni/La2O3-AI2O3>Ni/Y2O3-AI2O3>Ni/Fe2O3-AI2O3>Ni/AI2O3. The catalysts were characterized by CO2-TPD, O2-TPD and XPS methods. Here the relation between the order of resistance to carbon-deposition and performance of catalyst is discussed.     

Preparation of tungsten alkyl alkylidene alkylidyne complexes and kinetic studies of their formation

An equilibrium mixture of alkyl alkylidyne W(CH2SiMe3)3(CSiMe3)(PMe3) (1a) and its bis(alkylidene) tautomer W(CH2SiMe3)2(=CHSiMe3)2(PMe3) (1b) has been found to undergo an alpha-hydrogen abstraction reaction in the presence of PMe3 to form alkyl alkylidene alkylidyne W(CH2SiMe3)(=CHSiMe3)(CSiMe3)(PMe3)2 (2). In the presence of PMe3, the formation of 2 follows first-order kinetics, and the observed rate constant was found to be independent of the concentration of PMe3. The activation parameters for the formation of 2 are Delta H = 28.3(1.7) kcal/mol and Delta S = 3(5) eu. In the presence of PMe2Ph, an equilibrium mixture of W(CH2SiMe3)3(CSiMe3)(PMe2Ph) (3a) and its bis(alkylidene) tautomer W(CH2SiMe3)2(=CHSiMe3)2(PMe2Ph) (3b) was similarly converted to W(CH2SiMe3)(=CHSiMe3)(CSiMe3)(PMe2Ph)2 (4). The observed rate of this reaction was also independent of the concentration of PMe2Ph. These observations suggest a pathway in which the tautomeric mixtures 1a,b and 3a,b undergo rate-determining, alpha-hydrogen abstraction, followed by phosphine coordination, resulting in the formation of the alkyl alkylidene alkylidyne complexes 2 and 4.     

Structural and kinetic study of reversible CO2 fixation by dicopper macrocyclic complexes. From intramolecular binding to self-assembly of molecular boxes

A study of the reversible CO2 fixation by a series of macrocyclic dicopper complexes is described. The dicopper macrocyclic complexes [Cu2(OH)2(Me2p)](CF3SO3)2, 1(CF3SO3)2, and [Cu2(mu-OH)2(Me2m)](CF3SO3)2, 2(CF3SO3)2, (Scheme 1) containing terminally bound and bridging hydroxide ligands, respectively, promote reversible inter- and intramolecular CO2 fixation that results in the formation of the carbonate complexes [{Cu2(Me2p)}2(mu-CO3)2](CF3SO3)4, 4(CF3SO3)4, and [Cu2(mu-CO3)(Me2m)](CF3SO3)2, 5(CF3SO3)2. Under a N2 atmosphere the complexes evolve CO2 and revert to the starting hydroxo complexes 1(CF3SO3)2 and 2(CF3SO3)2, a reaction the rate of which linearly depends on [H2O]. In the presence of water, attempts to crystallize 5(CF3SO3)2 afford [{Cu2(Me2m)(H2O)}2(mu-CO3)2](CF3SO3)4, 6(CF3SO3)4, which appears to rapidly convert to 5(CF3SO3)2 in acetonitrile solution. [Cu2(OH)2(H3m)]2+, 7, which contains a larger macrocyclic ligand, irreversibly reacts with atmospheric CO2 to generate cagelike [{Cu2(H3m)}2(mu-CO3)2](ClO4)4, 8(ClO4)4. However, addition of 1 equiv of HClO4 per Cu generates [Cu2(H3m)(CH3CN)4]4+ (3), and subsequent addition of Et3N under air reassembles 8. The carbonate complexes 4(CF3SO3)4, 5(CF3SO3)2, 6(CF3SO3)4, and 8(ClO4)4 have been characterized in the solid state by X-ray crystallography. This analysis reveals that 4(CF3SO3)4, 6(CF3SO3)4, and 8(ClO4)4 consist of self-assembled molecular boxes containing two macrocyclic dicopper complexes, bridged by CO32- ligands. The bridging mode of the carbonate ligand is anti-anti-mu-eta1:eta1 in 4(CF3SO3)4, anti-anti-mu-eta2:eta1 in 6(CF3SO3)4 and anti-anti-mu-eta2:eta2 in 5(CF3SO3)2 and 8(ClO4)4. Magnetic susceptibility measurements on 4(CF3SO3)4, 6(CF3SO3)4, and 8(ClO4)4 indicate that the carbonate ligands mediate antiferromagnetic coupling between each pair of bridged CuII ions (J = -23.1, -108.3, and -163.4 cm-1, respectively, H = -JS1S2). Detailed kinetic analyses of the reaction between carbon dioxide and the macrocyclic complexes 1(CF3SO3)2 and 2(CF3SO3)2 suggest that it is actually hydrogen carbonate formed in aqueous solution on dissolving CO2 that is responsible for the observed formation of the different carbonate complexes controlled by the binding mode of the hydroxy ligands. This study shows that CO2 fixation can be used as an on/off switch for the reversible self-assembly of supramolecular structures based on macrocyclic dicopper complexes.     

四氯乙烯光解活泼自由基及其与烃或醇的夺氢反应的ESR研究

本文用自由基捕捉剂2,3,5,6-四甲基亚硝基苯(ND)与ESR相结合的方法研究了四氯乙烯光解活泼自由基及其与烃或醇的夺氢反应, 结果表明:1. Cl_2C=CCl_2光解首先产生Cl_2C=CCl及Cl, 而又可进一步加成为Cl_2C-CCl_3.2. 对于CH_3(CH_2)_nOH(n=3,7)及(CH_3)_2CH(CH_2)_nOH(n=1,2)而言, Cl_2C=CCl(或Cl)分别夺取其α-碳及叔碳上的氢, 以形成CH_3(CH_2)_(n-1)CHOH及(CH_3)_2C(CH_2)_nOH, 并为ND所捕获。3. Cl_2C=CCl(或Cl)分别夺取CH_3(CH_2)_nCH3(n=3,4,5,6), C_6H_5-CH_2CH_3及(CH_3)_2CH(CH_2)_nCH_3(n=1,4), (C_2H_5)_2CHCH_3, C_6H_5CH(CH_3)_2中亚甲基及叔碳上的氢, 以形成CH_3(CH_2)_mCH(CH_2)_(n-m-1)CH_3, C_6H_5CHCH_3及(CH_3)_2C(CH_2)_nCH_3, (C_2H_5)_2CCH_3, C_6H_5C(CH_3)_2.     

Syntheses of ketonated disulfide-bridged diruthenium complexes via C-H bond activation and C-S bond formation

The alpha-C-H bonds of 3-methyl-2-butanone, 3-pentanone, and 2-methyl-3-pentanone were activated on the sulfur center of the disulfide-bridged ruthenium dinuclear complex [(RuCl(P(OCH3)3)2)2(mu-S2)(mu-Cl)2] (1) in the presence of AgX (X = PF6, SbF6) with concomitant formation of C-S bonds to give the corresponding ketonated complexes [(Ru(CH3CN)2(P(OCH3)3)2)(mu-SSCHR1COR2)(Ru(CH3CN)3(P(OCH3)3)2)]X3 ([5](PF6)3, R1 = H, R2 = CH(CH3)2, X = PF6; [6](PF6)3, R1 = CH3, R2 = CH2CH3, X = PF6; [7](SbF6)3, R1 = CH3, R2 = CH(CH3)2, X = SbF6). For unsymmetric ketones, the primary or the secondary carbon of the alpha-C-H bond, rather than the tertiary carbon, is preferentially bound to one of the two bridging sulfur atoms. The alpha-C-H bond of the cyclic ketone cyclohexanone was cleaved to give the complex [(Ru(CH3CN)2(P(OCH3)3)2)(mu-SS-1- cyclohexanon-2-yl)(Ru(CH3CN)3(P(OCH3)3)2)](SbF6)3 ([8](SbF6)3). And the reactions of acetophenone and p-methoxyacetophenone, respectively, with the chloride-free complex [(Ru(CH3CN)3(P(OCH3)3)2)2(mu-S2)]4+ (3) gave [(Ru(CH3CN)2(P(OCH3)3)2)(mu-SSCH2COAr)(Ru(CH3CN)3(P(OCH3)3)2)](CF3SO3)3 ([9](CF3SO3)3, Ar = Ph; [10](CF3SO3)3, Ar = p-CH3OC6H4). The relative reactivities of a primary and a secondary C-H bond were clearly observed in the reaction of butanone with complex 3, which gave a mixture of two complexes, i.e., [(Ru(CH3CN)2(P(OCH3)3)20(mu-SSCH2COCH2CH3)(Ru(CH3CN)3(P(OCH3)3)2)](CF3SO3)3 ([11](CF3SO3)3) and [(Ru(CH3CN)2(P(OCH3)3)2)(mu-SSCHCH3COCH3)(Ru(CH3CN)3(P(OCH3)2)](CF3SO3)3 ([12](CF3SO3)3), in a molar ratio of 1:1.8. Complex 12 was converted to 11 at room temperature if the reaction time was prolonged. The relative reactivities of the alpha-C-H bonds of the ketones were deduced to be in the order 2 degrees > 1 degree > 3 degrees, on the basis of the consideration of contributions from both electronic and steric effects. Additionally, the C-S bonds in the ketonated complexes were found to be cleaved easily by protonation at room temperature. The mechanism for the formation of the ketonated disulfide-bridged ruthenium dinuclear complexes is as follows: initial coordination of the oxygen atom of the carbonyl group to the ruthenium center, followed by addition of an alpha-C-H bond to the disulfide bridging ligand, having S=S double-bond character, to form a C-S-S-H moiety, and finally completion of the reaction by deprotonation of the S-H bond.     

Redox chemistry of the acetato-bridged clusters [M3(mu3-O)n(mu-O2CCH3)6(H2O)3]2+ (M = Mo, W, n = 1, 2): reversible redox between mono-micro3-oxo d8 M(III)2M(IV) and d9 M(III)3 forms

A cyclic voltammogram of aqueous 0.1 mol dm(-3) triflic acid solutions of the d6 bioxo-capped M-M bonded cluster [Mo3(mu3-O)2(O2CCH3)6(H2O)3]2+ at a glassy carbon electrode at 25 degrees C gives rise to an irreversible 3e- cathodic wave to a d9 Mo(III)3 species at -0.8 V vs. SCE which on the return scan gives rise to two anodic waves at +0.05 V vs. SCE (E(1/2), 1e- reversible to d8 Mo(III)2Mo(IV)) and +0.48 V vs. SCE (2e- irreversible back to d6 Mo(IV)3). The number of electrons passed at each redox wave has been confirmed by redox titration and controlled potential electrolysis which resulted in 90% recovery of [Mo3(mu3-O)2(O2CCH3)6(H2O)3]2+ following electrochemical re-oxidation at +0.8 V. A corresponding CV study of the d8 monoxo-capped W(III)2W(IV) cluster [W3(mu3-O)(O2CCH3)6(H2O)3]2+ gives rise to a reversible 1e- cathodic process at -0.92 V vs. SCE to give the d9 W(III)3 species [W3(mu3-O)(O2CCH3)6(H2O)3]+; the first authentic example of a W(III) complex with coordinated water ligands. However the cluster is too unstable (O2/water sensitive) to allow isolation. Comparisons with the cv study on [Mo3(mu3-O)2(O2CCH3)6(H2O)3]2+ suggest irreversible reduction of this complex to monoxo-capped [Mo(III)3(mu3-O)(O2CCH3)6(H2O)3]+ followed by reversible oxidation to its d8 counterpart [Mo3(mu3-O)(O2CCH3)6(H2O)3]2+ (Mo(III)2Mo(IV)) and finally irreversible oxidation back to the starting bioxo-capped cluster. Exposing the d9 Mo(III)3 cluster to air (O2) however gives a different final product with evidence of break up of the acetate bridged framework. Corresponding redox processes on d6 [W3(mu3-O)2(O2CCH3)6(H2O)3]2+ are too cathodic to allow similar generation of the monoxo-capped W(III)3 and W(III)2W(IV) clusters at the electrode surface.     

Synthesis, characterization, and reactivity of ferrous and ferric oxo/peroxo pivalate complexes in relation to Gif-type oxygenation of substrates

This study examines structural features and aspects of reactivity of Gif-type reagents, which depend on O2/Zn to mediate oxidation of hydrocarbons. The reagents investigated derive from the use of iron complexes with the anion of the weak carboxylic acid Me3CCO2H (pivalic acid (PivH)) in pyridine/PivH. In these solutions, the known compound [Fe3O(O2CCMe3)6(py)3] is reduced by Zn to generate yellow-green [FeII(O2CCMe3)2(py)4], which readily reverts to [Fe3O(O2CCMe3)6(py)3], and eventually to [Fe3O(O2CCMe3)6(py)3]+, upon exposure to dioxygen. All three species are equally well suited to mediate Gif-like oxygenation of substrates supported by O2/Zn. [FeIII3O(O2CCMe3)6(L)3]+ (L = H2O, py) is converted by H2O2 to afford the hexairon(III) peroxo compounds [Fe6(O2)(O)2(O2CCMe3)12(L)2] (L = Me3CCO2H, py), which feature a [Fe6(eta 2-mu 4-O2)(mu 3-O)2] core previously documented in the closely related [Fe6(O2)(O)2(O2CPh)12(H2O)2]. A similar peroxo species, [Fe6(O2)(O)2(O2CCMe3)2(O2CCF3)10(H2O)2], is obtained upon replacing all pivalate ligands by trifluoroacetate groups with the exception of those pivalates that bridge between the two [Fe3O(O2CCF3)5(H2O)]2+ units. The structure of the [Fe6(O2)(O)2] core in these peroxo species is found to range from a recliner to a butterfly-type conformation. Reduction of [Fe6(O2)(O)2(O2CCMe3)12(HO2CCMe3)2] with NaBH4 generates [Na2Fe4(O)2(O2CCMe3)10(L)(L')] (L = CH3CN, L' = Me2CO; L = L' = Me3CCO2H), which feature a [Na2Fe4(O)2] core possessing a bent butterfly conformation of the [Fe4(O)2] unit. Oxidation of the same peroxo complex by CeIV or NOBF4 regenerates the oxo-bridged [Fe3O(O2CCMe3)6(solv)3]+ (solv = EtOH, H2O, thf). Employment of the sterically encumbered 2-Me-5-Etpyridine provides the tetrairon compound [Fe4(O)2(O2CCMe3)8(2-Me-5-Etpy)2], which can be readily transformed upon treatment with H2O2 to the asymmetric peroxo complex [Fe6(O2)(O)2(O2CCMe3)12(2-Me-5-Etpy)2]. The peroxo-containing complexes oxidize both cis-stilbene and adamantane in either benzene or py/PivH, but only under forceful conditions and at very low yields. The low reactivity and high selectivity (tert/sec = 8) obtained in the oxidation of adamantane suggests that the present type of peroxo species is not directly involved in catalytic Gif-type oxygenations of adamantane.     

CrO3在γ-Al2O3和SiO2载体表面的分散状态

用X光衍射(XRD)方法研究了CrO_3/SiO_2和CrO_3/γ-Al_2O_3体系。用相定量外推法测定活性组份在载体表面的最大分散量。在干燥气氛中将CrO_3与载体混合, 并在低于CrO_3熔点的温度下烘烤制备样品, 实验得到CrO_3在SiO_2或者γ-Al_2O_3表面的最大分散量都随温度的升高而增大。CrO_3在SiO_2表面的最大分散量由101 ℃的0.27gCrO_3/g SiO_2到170 ℃的0.38g CrO_3/g SiO_2; CrO_3在γ-Al_2O_3表面的最大分散量由120 ℃的0.22g CrO_3/g γ-Al_2O_3到171 ℃的0.42g CrO_3/g γ-Al_2O_3。CrO_3在SiO_2或γ-Al_2O_3表面的最大分散量超过密置单层量, 可由易聚合形成同多酸根来解释。     

Anisole-diphenoxide ligands and their zirconium dichloride and dialkyl complexes

Linear triphenol H3[RO3] (2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-R-phenol; R = Me, tBu) was found to undergo selective mono-deprotonation and mono-O-methylation. Deprotonation of H3[RO3] with 1 equiv of nBuLi resulted in the formation of Li{H2[RO3]}(Et2O)2 (R = Me (1a), tBu (1b)), in which the central phenol unit was lithiated. Treatment of H3[RO3] with methyl p-toluenesulfonate in the presence of K2CO3 in CH3CN gave the corresponding anisol-diphenol H2[RO2O] (2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-R-anisole; R = Me (2a), tBu (2b)). Reaction of H2[RO2O] with 2 equiv of nBuLi gave the dilithiated derivatives Li2[RO2O]. The lithium salts were reacted with ZrCl4 in toluene/THF to obtain the dichloride complex [RO2O]ZrCl2(thf) (R = Me (3a), tBu (3b)). 3b underwent dimerization along with a loss of THF to generate {[tBuO2O]ZrCl2}2 (4), whereas 4 was dissolved in THF to regenerate the monomer 3b. Alkylation of 3 with MeMgBr, PhCH2MgCl, and Me3SiCH2MgCl gave [MeO2O]ZrMe2(thf) (5), [RO2O]Zr(CH2Ph)2 (R = Me (6a), tBu (6b)), and [tBuO2O]Zr(CH2SiMe3)2 (7), respectively. Reaction of 3b with LiBHEt3 produced the hydride-bridged dimer [Li2(thf)4Cl]{[tBuO3]Zr}2(micro-H)3} (8), in which demethylation of the dianionic [tBuO2O] ligand took place to give the trianionic [tBuO3] ligand. The X-ray crystal structures of 1b, 2a, 3a, 4, 6a, and 7 were reported.     

Synthesis of 3-hexahelicenol and its transformation to 3-hexahelicenylamines,diphenylphosphine, methyl carboxylate,and dimethylthiocarbamate

A nonphotochemical synthetic route to 3-hexahelicenol is reported. It involves a key [2+2+2] cycloisomerization of CH(3)O-substituted triyne that is readily available from 1-methoxy-3-methylbenzene and 1-bromo-2-(bromomethyl)naphthalene. Further functional group transformations led to 3-CO(2)CH(3), 3-NH(2), 3-PPh(2), and 3-SC(O)N(CH(3))(2) substituted hexahelicenes.     

Diruthenium dithiolato cyanides: basic reactivity studies and a post hoc examination of nature's choice of Fe versus Ru for hydrogenogenesis

The reaction of Ru2(S2C3H6)(CO)6 (1) with 2 equiv of Et4NCN yielded (Et4N)2[Ru2(S2C3H6)(CN)2(CO)4], (Et4N)2[3], which was shown crystallographically to consist of a face-sharing bioctahedron with the cyanide ligands in the axial positions, trans to the Ru-Ru bond. Competition experiments showed that 1 underwent cyanation >100x more rapidly than the analogous Fe2(S2C3H6)(CO)6. Furthermore, Ru2(S2C3H6)(CO)6 underwent dicyanation faster than [Ru2(S2C3H6)(CN)(CO)5]-, implicating a highly electrophilic intermediate [Ru2(S2C3H6)(mu-CO)(CN)(CO)5]-. Ru2(S2C3H6)(CO)6 (1) is noticeably more basic than the diiron compound, as demonstrated by the generation of [Ru2(S2C3H6)(mu-H)(CO)6]+, [1H]+. In contrast to 1, the complex [1H]+ is unstable in MeCN solution and converts to [Ru2(S2C3H6)(mu-H)(CO)5(MeCN)]+. (Et4N)2[3] was shown to protonate with HOAc (pKa = 22.3, MeCN) and, slowly, with MeOH and H2O. Dicyanide [3]2- is stable toward excess acid, unlike the diiron complex; it slowly forms the coordination polymer [Ru2(S2C3H6)(mu-H)(CN)(CNH)(CO)4]n, which can be deprotonated with Et3N to regenerate [H3]-. Electrochemical experiments demonstrate that [3H]- catalyzes proton reduction at -1.8 V vs Ag/AgCl. In contrast to [3]2-, the CO ligands in [3H]- undergo displacement. For example, PMe3 and [3H]- react to produce [Ru2(S2C3H6)(mu-H)(CN)2(CO)3(PMe3)]-. Oxidation of (Et4N)2[3] with 1 equiv of Cp2Fe+ gave a mixture of [Ru2(S2C3H6)(mu-CO)(CN)3(CO)3]- and [Ru2(S2C3H6)(CN)(CO)5]-, via a proposed [Ru2]2(mu-CN) intermediate. Overall, the ruthenium analogues of the diiron dithiolates exhibit reactivity highly reminiscent of the diiron species, but the products are more robust and the catalytic properties appear to be less promising.     

Regioselective synthesis of indenols via nickel-catalyzed carbocyclization reaction

2-Halophenyl ketones 1a-e (1a, o-IC(6)H(4)COCH(3)) undergo carbocyclization with alkyl propiolates (2a, CH(3)(CH(2))(4)C[triple bond]CCO(2)CH(3); 2b, TMSC[triple bond]CCO(2)Et 2c, CH(3)C[triple bond]CCO(2)CH(3); 2d, CH(3)OCH(2)C[triple bond]CCO(2)CH(3); 2e, CH(3)(CH(2))(3)C[triple bond]CCO(2)CH(3); 2f, PhC[triple bond]CCO(2)CH(3); and 2g, (CH(3))(3)C[triple bond]CCO(2)CH(3)) in the presence of Ni(dppe)Br(2) and zinc powder in acetonitrile at 80 degrees C to afford the corresponding indenol derivatives 3a-m with remarkable regioselectivity in good to excellent yields. The nickel-catalyzed carbocyclization reaction was successfully extended to other simple disubstituted alkynes. Thus, the reaction of 2-halophenyl ketones 1a-e with disubstituted alkynes (2h, PhC[triple bond]CPh; 2i, CH(3)C(6)H(4)C[triple bond]CC(6)H(4)CH(3); 2j, CH(3)CH(2)C[triple bond]CCH(2)CH(3); 2k, PhC[triple bond]CCH(3); 2l, TMSC[triple bond]CCH(3); and 2m, PhC[triple bond]C(CH(2))(3)CH(3)) proceeded smoothly to afford the corresponding indenols 4a-t in good to excellent yields. For unsymmetrical alkynes 2k-m, the carbocyclization gave two regioisomers with regioselectivities ranging from 1:2 to 1:12 depending on the substituents on the alkyne and on the aromatic ring of halophenyl ketone. A possible mechanism for this nickel-catalyzed carbocyclization reaction is also proposed.     

NF3 decomposition over some metal oxides in the absence of water

NF3 decomposition in the absence of water over Al2O3, Fe2O3, Co3O4 and NiO, and transition metal oxides (Fe2O3, Co3O4 and NiO) coated Al2O3 reagents was investigated. The results show that Al2O3 is an active reagent for NF3 decomposition with 100% conversion lasting for 8.5 h at 400 ℃. Fe2O3, Co3O4 and NiO coated Al2O3 reagents are superior to bare Al2O3, and 5%Co3O4/Al2O3 has a high reactivity with NF3 full conversion maintaining for 10.5 h. It is suggested that the presence of transition metal oxide is beneficial to the reactivity of Al2O3, and results in a significant enhancement in the fluorination of Al2O3.     

Metal-templated diyne cyclodimerization and cyclotrimerization

Reaction of [Pt(CH3)2(COD)] (COD = 1,5-cyclooctadiene) with Ph2PCCCCPPh2 led to a mixture of [{Pt(CH3)2}2(mu-Ph2PC4PPh2)2] (1) and [{Pt(CH3)2}3(mu-Ph2PC4PPh2)3] (2). Reaction of [PtCl2(COD)] with Ph2PCCCCPPh2 led to a mixture of the thermally unstable compounds [{PtCl2}2(mu-Ph2PC4PPh2)2] (3) and [{PtCl2}3(mu-Ph2PC4PPh2)3] (4) which transform into [{PtMe2}2{mu-C8(PPh2)4}] (5) and [{PtMe2}3{mu3-C12(PPh2)6}] (6) containing 8-membered diene-diyne and 12-membered triene-triyne rings, respectively. Compound 2 can be converted to [{PtMe2}3{C12(PPh2)6}] (7) by heating with CuCl at 80 degrees C, while 1 can be heated without significant cycloaddition.     

纤维状TiO2／Bi2O3光催化剂的制备及其光催化性能

研究了SrCo0．7Fe0．2Mo0．103-δ（SCFM）材料的相组成、微观结构、热膨胀系数、氧渗透性能和化学稳定性,其结果和文献中的SrCo0．8Fe0.2O3-δ（SCF）做了对比．通过EDTA-citric混合方法成功获得了纯相SCFM材料．SCFM材料在500-1050℃显示出比SCF材料更低的热膨胀系数（24×10^-6-29×10^-6／K）,表明其具有一种更稳定的结构,尽管由于Mo掺杂造成其透氧率比SCF材料低,但是SCFM的透氧率仍然维持在一个较高水平．证实SCF中的Mo掺杂能够阻止晶格中的有序-无序转变,提高了其在CO2下的化学稳定性．     

多氟代烃类的反应II: 氟氯烯烃与三氯化铝的反应

研究了以CFCl2CF2CF=CF2(1)和CFCl2CF=CFCF2(2)为原料与三氯化铝的反应.结果获得重排产品CCl2=CF2CF2CF3(3).结果支持了从1到3的分子间重排反应的机理.在激烈条件下,3进一步与氯化铝反应得到CCl2=CFCCl2CF3(4),CCl2=CClCCl2CF3(5),CCl2=CClCCl2CClF(6),CCl2=CClCCl2CFCCl2(7)和CCl2=CClCCl2CCl3(8).由分离所得产品的结构可推断化合物3中氟原子被氯原子取代的稳定性按以下次序:CF3->CF=>=-CF2CF=.反应条件对产品得率的影响也被讨论了.     

Synthesis of CuII-RuII-CuII trinuclear complexes via redox reaction of copperI across thiosemicarbazones coordinated to rutheniumII

Pyridine-2-carbaldehyde thiosemicarbazones [C5H4N1-C(H)N2-N3H-C(S)-N4HR, R = H, L1H2; CH3, L2H2-Me; CH2CH3, L3H2-Et] with Ru(PPh3)3Cl2 have formed mononuclear RuII precursors for the generation of trinuclear complexes. The reaction of 2 mol each of L1H2, L2H2-Me, or L3H2-Et with Ru(PPh3)3Cl2 in the presence of Et3N has yielded mononuclear complexes [Ru(N3,S-L1H)2(PPh3)2] (1), [Ru(N3,S-L2H-Me)2(PPh3)2] (2), and [Ru(N3,S-L3H)2(PPh3)2] (3). The addition of 2 equiv of copperI chloride solution to complex 1 in acetonitrile has formed a novel trinuclear complex, (Ph3P)2RuII(L1)2CuII2Cl2 (4), in which the pendant amino group (-N4H2) loses one hydrogen along with the oxidation of CuI to CuII. In this complex, RuII is bonded to two P, two S, and two N3 atoms, while each CuII is coordinated to N1, N2, N4, and Cl atoms. Reaction with copper(I) bromide yielded a similar trinuclear complex, (Ph3P)2Ru(L1)2CuII2Br2 (5). From precursors 2 and 3, analogous complexes (Ph3P)2RuII(L2-Me)2CuII2Cl2 (6), (Ph3P)2RuII(L2-Me)2CuII2Br2 (7), (Ph3P)2RuII(L3-Et)2CuII2Cl2 (8), and (Ph3P)2RuII(L3-Et)2CuII2Br2 (9) have been synthesized. These complexes have been characterized using analytical, spectroscopic, and electrochemical techniques. Single-crystal X-ray crystallography has been carried out for precursor 2 and all of the trinuclear complexes, 4-9. X-band electron spin resonance and UV-vis spectra have confirmed the presence of CuII. The cyclic voltammetry studies support the RuII/RuIII redox behavior of this metal in trinuclear complexes.