利用TiO2/SO42-光触媒催化还原CO2之参数影响与反应路径探讨

将改良式溶胶-凝胶法制备的酸性触媒TiO2/SO24-涂布于不锈钢网上,并利用自行设计之批次式光催化反应器,在三组近紫外灯管(波长为365nm,光强度为2.0mW/cm2)照射下,进行CO2光催化还原反应操作参数(还原剂种类、CO2初始浓度和反应温度)之影响研究.结果显示,使用氢气为还原剂可获得最高的光催化还原速率,光还原反应之主要气态产物为CO和甲烷,其次为微量的乙烯与乙烷.同时,光催化还原速率亦随着CO2初始浓度及反应温度的提高而增加.FT-IR光谱分析发现,TiO2/SO42-光触媒表面有甲酸、甲醇、碳酸盐、甲酸盐及甲酸甲酯等产物之存在.TiO2/SO42-光触媒催化还原CO2有两种可能反应路径,其中一种反应路径生成CO,CH4,C2H4及C2H6等气态产物;而另一种反应路径则生成CO23a-ds,CH3OHads,HCOOa-ds,HCOOHads,HCOHads与HCOOCH3ads等吸附在光触媒表面的产物.     

酶促合成油酸香茅醇酯的超临界连续反应-分离过程

将固定床动态酶促反应过程和超临界二氧化碳萃取分离过程相耦合,设计并建立了一套超临界相反应分离一体化的实验装置。在该装置上初步考察了反应压力和温度对脂肪酶催化油酸甲酯和外消旋香茅醇酯交换反应的影响。结果表明,我们所建立的反应装置能有效地实现反应分离一体化过程;当体系压力接近二氧化碳的临界压力时反应速率最高;9MPa压力下反应温度为328K时反应转化率最高,而在14MPa压力下反应转化率在308K～328K之间随着温度的升高而增大。     

Synthesis and spectroscopic studies of some new metal carbonyl derivatives of 1-(2-pyridylazo)-2-naphthol

Interaction of 1-(2-pyridylazo)-2-naphthol (PAN) with [Mo(CO)₆] in air resulted in formation of the tricarbonyl oxo-complex [Mo(O)(CO)₃(PAN)], 1. The dicarbonyl complex [Ru(CO)₂(PAN)], 3, was obtained from the reaction of [Ru₃(CO)₁₂] with PAN. In presence of triphenyl phosphine (PPh₃), the reaction of PAN with either Mo(CO)₆ or Ru₃(CO)₁₂ gave [Mo(CO)₃(PAN)(PPh₃)], 2, and [Ru(CO)₂(PAN)(PPh₃)], 4. All the complexes were characterized by elemental analysis, mass spectrometry, IR, and NMR spectroscopy. The thermal properties of the complexes were also investigated by thermogravimetry.     

Reaction of the radical pair NO2* and CO3*- with 2-[6-(4'-amino)phenoxy-3H-xanthen-3-on-9-yl]benzoic acid (APF)

The fluorogenic indicator 2-[6-(4'-amino)phenoxy-3H-xanthen-3-on-9-yl]benzoic acid (APF) is used widely to detect and measure reactive nitrogen and oxygen species such as peroxynitrite, ONOO-, both in vivo and in vitro. We present in this work the results of a combined computational and experimental study to provide insights into the mechanism of the reaction of APF with the radical products of ONOO- reaction with CO2, namely NO2* and CO3*-. The experimental study on the inhibition of APF oxidation by HCO3- suggests that a direct reaction of APF with nitrosoperoxycarbonate, ONOOCO2-, is unlikely. The mechanism of APF action on NO2* and CO3*- was investigated using gas-phase and solvent modeled calculations at the MPW1K/6-311+G(d)//MPW1K/6-31G(d) level of theory. Our computational results suggest that two-electron oxidation of APF takes place in two rapid one-electron oxidation steps, the first being a proton-coupled electron transfer (PCET) between APF and NO2*, followed by addition of CO3*- and subsequent decomposition of the adduct to yield fluorescein.     

Synthesis of 2-substituted 3-aroylindenes via palladium-catalyzed carbonylative cyclization of diethyl 2-(2-(1-alkynyl)phenyl)malonates with aryl halides

[reaction: see text] The palladium-catalyzed reaction of readily accessible diethyl 2-(2-(1-alkynyl)phenyl)malonates with aryl halides under a balloon pressure of CO produced 2-substitued 3-aroylindenes in good yields. The reaction is believed to proceed via cyclization of the alkyne containing a proximate nucleophilic center promoted by an acylpalladium complex.     

Catalytic CO oxidation by free Au2-: experiment and theory

Temperature-dependent rf-ion trap mass spectrometry and first-principles simulations reveal the detailed reaction mechanism of the catalytic gas-phase oxidation of CO by free Au(2)(-) ions in the presence of O(2). A metastable intermediate with a mass of Au(2)CO(3)(-) was observed at low temperatures. Two alternative structures corresponding to digold carbonate or peroxyformate are predicted for this intermediate. Both structures are characterized by low activation barriers for the formation of CO(2). These combined experimental and theoretical investigations provide a comprehensive understanding of the kinetics, energetics, and atomic arrangements along the reaction path, thus allowing a formulation of the catalytic cycle for the oxidation reaction.     

Hypervalent organobismuth(iii) carbonate, chalcogenides and halides with the pendant arm ligands 2-(Me2NCH2)C6H4 and 2,6-(Me2NCH2)2C6H3

R2BiOH (1) [R = 2-(Me2NCH2)C6H4] and (R2Bi)2O (2) are formed by hydrolysis of R2BiCl with KOH. Single crystals of were obtained by air oxidation of (R2Bi)2. The reaction of R2BiCl and Na2CO3 leads to (R2Bi)2CO3 (3). 3 is also formed by the absorption of CO2 from the air in solutions of 1 or 2 in diethyl ether or toluene. (R2Bi)2S (4) is obtained from R2BiCl and Na2S or from (R2Bi)2 and S8. Exchange reactions between R2BiCl and KBr or NaI give R2BiX [X = Br (5), I (6)]. The reaction of RBiCl2 (7) with Na2S and [W(CO)5(THF)] gives cyclo-(RBiS)2[W(CO)5]2 (8). cyclo-(R'BiS)2 (9) [R' = 2,6-(Me2NCH2)2C6H3] is formed by reaction of R'BiCl2 and Na2S. The structures of were determined by single-crystal X-ray diffraction.     

HYDROGENATION OF CO_2 OVER A YBa_2Cu_3O_(6～7) CATALYST

研究了ＹＢａＣｕ３Ｏ６～７超导催化剂上ＣＯ２的加氢制醇反应。考察了温度、压力和空速等条件对催化剂反应性能的影响。反应的主要产物是甲醇、ＣＯ和少量甲醚。利用ＸＰＳ、ＸＲＤ和ＡＦＭ等技术对催化剂的结构、铜的存在状态和反应活性位进行表征发现，在反应过程中，ＹＢａ２Ｃｕ３Ｏ６～７由ｏｒｔｈｏｍｂｉｃ相转变为ｔｅｔｒａｇｏｎａｌ相。反应活性位可能是Ｃｕ（Ｉ）物种。反应后催化剂颗粒的分散程度明显提高     

基于1-(2-吡啶甲基)-1, 2, 4-三唑的金属有机化合物的合成及反应研究

本文合成了1-（2-吡啶甲基）-1,2,4-三唑（L）,并研究了其与有机锡和羰基钼（钨）的配位反应,合成了通过三唑4位氮原子以单齿形式配位的有机锡衍生物L₂SnR₂Cl₂（R=Me,n-Bu或Ph）和羰基金属配合物LM（CO）₅（M=Mo或W）,以及N,N螯合双齿配位的四羰基金属配合物LM（CO）₄。当用氯化苄处理L时,制得了相应的三唑盐,该盐用氧化银处理后与M（CO）₅THF或M（CO）₄（NHC₅H₁₀）₂（NHC₅H₁₀为哌啶）反应,得到了基于三唑的氮杂环卡宾衍生物L’M（CO）₅和L’M（CO）₄（L’=1-（2-吡啶甲基）-4-苄基-1,2,4-三唑-5-碳烯）。X-射线单晶衍射分析表明,在L’M（CO）₅中氮杂环卡宾配体L’表现为通过卡宾碳配位的单齿配体;而在L’M（CO）₄中,L’表现为通过卡宾碳和吡啶氮原子配位的螯合[C,N]双齿配体。     

基于1-(2-吡啶甲基)-1,2,4-三唑的金属有机化合物的合成及反应研究(英文)

合成了1-(2-吡啶甲基)-1,2,4-三唑(L)并研究了其与有机锡和羰基钼(钨)的配位反应,合成了通过三唑4位氮原子以单齿形式配位的有机锡衍生物L2SnR2Cl2(R=Me,n-Bu或Ph)和羰基金属配合物LM(CO)5(M=Mo或W),以及N,N螯合双齿配位的四羰基金属配合物LM(CO)4。当用氯化苄处理L时,制得了相应的三唑盐,该盐用氧化银处理后与M(CO)5THF或M(CO)4(NHC5H10)2(NHC5H10为哌啶)反应,得到了基于三唑的氮杂环卡宾衍生物L′M(CO)5和L′M(CO)4(L′=1-(2-吡啶甲基)-4-苄基-1,2,4-三唑-5-碳烯)。X-射线单晶衍射分析表明,在L′M(CO)5中氮杂环卡宾配体L′表现为通过卡宾碳配位的单齿配体;而在L′M(CO)4中,L′表现为通过卡宾碳和吡啶氮原子配位的螯合[C,N]双齿配体。     

SURFACE STUDIES ON A YBa_2Cu_3O_(6～7) CATALYST FOR CO_2 HYDROGENATION TO METHANOL

研究了ＹＢａ２Ｃｕ３Ｏ６～７超导催化剂上ＣＯ２的加氢反应。应用ＴＰＤ、ＴＰＲ、ＳＥＭ和原位ＦＴＩＲ等技术对催化剂进行表征发现，ＣＯ２极易吸附到ＹＢａ２Ｃｕ３Ｏ６～７催化剂的氧空位上。反应过的催化剂易被还原。反应的中间物种是醛基和甲酸根。根据ＦＴＩＲ结果提出甲醇是ＣＯ２和Ｈ２反应的直接产物，ＣＯ２＋Ｈ２→ＣＨ３ＯＨ＋Ｈ２Ｏ和ＣＯ２＋Ｈ２→ＣＯ＋Ｈ２Ｏ是体系中存在的平行反应     

(S)-(2-(2'-Pyridyl)ethyl)cysteamine and (S)-(2-(2'-pyridyl)ethyl)-d,l-homocysteine as ligands for the "fac-[M(CO)(3)](+)" (M = Re, (99m)Tc) core

The reaction of fac-[NEt(4)](2)[Re(CO)(3)Br(3)] with (S)-(2-(2'-pyridyl)ethyl)cysteamine, L(1), in methanol leads to the formation of the cationic fac-[Re(CO)(3)(NSN)][Br] complex, 1, with coordination of the nitrogen of the pyridine, the sulfur of the thioether, and the nitrogen of the primary amine. When fac-[NEt(4)](2)[Re(CO)(3)Br(3)] reacts with the homocysteine derivative (S)-(2-(2'-pyridyl)ethyl)-d,l-homocysteine, L(2), the neutral fac-Re(CO)(3)(NSO) complex, 2, is produced with coordination of the nitrogen of the primary amine, the sulfur of the thioether, and the oxygen of the carboxylate group, while the pyridine ring remains uncoordinated. The analogous technetium-99m complexes, 1' and 2', were also prepared quantitatively by the reaction of L(1) and L(2) with the fac-[(99m)Tc(CO)(3)(H(2)O)(3)](+) precursor at 70 degrees C in water. Given that both (S)-(2-(2'-pyridyl)ethyl)cysteamine and homocysteine can be easily N- or S-derivatized by a bioactive molecule of interest, both the NSN or NSO ligand systems could be used to develop target-specific radiopharmaceuticals for diagnosis and therapy.     

Regio- and stereocontrolled synthesis of novel 3-sulfonamido-2,3,4,5-tetrahydro-1,5-benzothiazepines from 2-(bromomethyl)- or 2-(sulfonyloxymethyl)aziridines

2-(Bromomethyl)-1-sulfonylaziridines were converted into novel 3-sulfonamido-2,3,4,5-tetrahydro-1,5-benzothiazepines upon treatment with 2-aminothiophenol in THF in the presence of K2CO3. Starting from 3-substituted 2-(sulfonyloxymethyl)aziridines, a regio- and stereocontrolled synthesis of trans-2-phenyl- and trans-4-(phenyl or propyl)-3-sulfonamido-2,3,4,5-tetrahydro-1,5-benzothiazepines was developed in good yields via two different reaction pathways, depending on the nature of the sulfonyloxy group.     

Synthesis of 3-(aminomethylene)-2-oxoindolines by palladium-catalyzed annulation of 3-chloro-2-iodo-N-arylacrylamides with amides or amines

A new palladium-catalyzed C-H bond activation-annulation-amination tandem method was presented for selectively synthesizing 3-(aminomethylene)-2-oxoindolines. In the presence of Pd(dba)(2), xantphos (L8), AgOAc and Na(2)CO(3), a variety of 3-chloro-2-iodo-N-arylacrylamides underwent the reaction with amides or amines to afford the corresponding 3-(aminomethylene)-2-oxoindolines in moderate to good yields.     

Unprecedented migration of a methyl group in 2-(2',6'-dimethylphenylazo)-4-methylphenol mediated by ruthenium

An unprecedented chemical transformation of 2-(2',6'-dimethylphenylazo)-4-methylphenol has been observed upon its reaction with [Ru(PPh(3))(2)(CO)(2)Cl(2)] whereby the methyl group at the 2' position migrates to the 4' or 6' position.     

Vibrational predissociation spectrum of the carbamate radical anion, C(5)H(5)N-CO(2)(-), generated by reaction of pyridine with (CO(2))(m)(-)

We report the vibrational predissociation spectrum of C(5)H(5)N-CO(2)(-), a radical anion which is closely related to the key intermediates postulated to control activation of CO(2) in photoelectrocatalysis with pyridine (Py). The anion is prepared by the reaction of Py vapor with (CO(2))(m)(-) clusters carried out in an ionized, supersonic entrainment ion source. Comparison with the results of harmonic frequency calculations establishes that this species is a covalently bound molecular anion derived from the corresponding carbamate, C(5)H(5)N-CO(2)(-) (H(+)). These results confirm the structural assignment inferred in an earlier analysis of the cluster distributions and photoelectron spectra of the mixed Py(m)(CO(2))(n)(-) complexes [J. Chem. Phys. 2000, 113 (2), 596-601]. The spectra of the (CO(2))(m)(-) (m = 5 and 7) clusters are presented for the first time in the lower energy range (1000-2400 cm(-1)), which reveal several of the fundamental modes that had only been characterized previously by their overtones and combination bands. Comparison of these new spectra with those displayed by Py(CO(2))(n)(-) suggests that a small fraction of the Py(CO(2))(n)(-) ions are trapped entrance channel reaction intermediates in which the charge remains localized on the (CO(2))(m)(-) part of the cluster.     

Substitution, cage functionalization, and oxidation of the charge-compensated triruthenium monocarbollide cluster complex [1-SMe2-2,2-(CO)2-7,11-(mu-H)2-2,7,11-{Ru2(CO)6}-closo-2,1-RuCB10H8

The compound [1-SMe2-2,2-(CO)2-7,11-(mu-H)2-2,7,11-{Ru2(CO)6}-closo-2,1-RuCB10H8] 1a reacts with PMe3 or PCy3(Cy = cyclo-C6H11) to give the structurally different species [1-SMe2-2,2-(CO)2-7,11-(mu-H)2-2,7,11-{Ru2(CO)5(PMe3)}-closo-2,1-RuCB10H8] 4 and [1-SMe2-2,2-(CO)2-11-(mu-H)-2,7,11-{Ru2(mu-H)(CO)5(PCy3)}-closo-2,1-RuCB10H8]5, respectively. A symmetrically disubstituted product [1-SMe2-2,2-(CO)2-7,11-(mu-H)2-2,7,11-{Ru2(CO)4(PMe3)2}-closo-2,1-RuCB10H8] 6 is obtained using an excess of PMe3. In contrast, the chelating diphosphines 1,1'-(PPh2)2-Fe(eta-C5H4)2 and 1,2-(PPh2)2-closo-1,2-C2B10H10 react with 1a to yield oxidative-insertion species [1-SMe2-2,2-(CO)2-11-(mu-H)-2,7,11-{Ru2(mu-H)(micro-[1',1'-(PPh2)2-Fe(eta-C5H4)2])(CO)4}-closo-2,1-RuCB10H8] 7 and [1-SMe2-2,2-(CO)2-11-(mu-H)-2,7,11-{Ru2(mu-H)(CO)4(1',2'-(PPh2)2-closo-1',2'-C2B10H10)}-closo-2,1-RuCB10H8] 8, respectively. In toluene at reflux temperatures, 1a with Bu(t)SSBu(t) gives [1-SMe2-2,2-(CO)2-7-(mu-SBu(t))-11-(mu-H)-2,7,11-{Ru2(mu-H)(mu-SBu(t))(CO)4}-closo-2,1-RuCB10H8] 9, and with Bu(t)C [triple bond] CH gives [1-SMe2-2,2-(CO)2-7-{mu:eta2-(E)-CH=C(H)Bu(t)}-11-{mu:eta2-(E)-CH=C(H)Bu(t)}-2,7,11-{Ru2(CO)5}-closo-2,1-RuCB10H8] 10. In the latter, two alkyne groups have inserted into cage B-H groups, with one of the resulting B-vinyl moieties involved in a C-H...Ru agostic bond. Oxidation of 1a with I2 or HgCl2 affords the mononuclear ruthenium complex [1-SMe2-2,2,2-(CO)3-closo-2,1-RuCB10H10] 11.     

Catalytic involvement of CO2 in the mutagenesis caused by reactions of ONOO(-) with guanine

The catalytic role of CO2 in reactions of ONOO- with guanine, leading to the formation of the mutagenic species 8-oxoguanine (8-oxoG) and 8-nitroguanine anion (8-nitroG-), was investigated by considering the reactions of nitrosoperoxycarbonate anion (ONOOCO2-), an adduct of ONOO- and CO2, with guanine at the B3LYP/6-31G** and B3LYP/AUG-cc-pVDZ levels of density functional theory in gas phase. In order to study bulk solvent effect, single-point energy calculations in aqueous media were carried out for all the species occurring in the reactions at the B3LYP/AUG-cc-pVDZ level of theory, by use of the polarizable continuum model (PCM). Vibrational frequency analysis was performed, and zero-point-energy (ZPE)-corrected total energies and Gibbs free energy changes at 298.15 K were obtained. The genuineness of the calculated transition states was confirmed by visually examining the vibrational modes and also by intrinsic reaction coordinate (IRC) calculations. The reaction between ONOOCO2- and guanine occurring through four different mechanisms leads to the formation of 8-oxoG or its anion, while the reaction between the same two species occurring through a different scheme leads to the formation of 8-nitroG-. It has been shown that the presence of a water molecule along with ONOOCO2- would not affect the reaction mechanisms significantly. Structures of the reactant complexes, product complexes and barrier energies involved in the reactions reveal that CO2 acts as a catalyst for the reaction between ONOO- and guanine. The cause of the catalytic action of CO2 is mainly due to intermediacy of the CO3 radical anion and NO2 radical into which ONOOCO2- is fragmented while reacting with guanine. The relative stabilities of the different product complexes suggest that the mutation caused by ONOO- in the presence of CO2 would mainly involve 8-oxoG.     

The inter-conversions of platinum carbonyl dianionic clusters, [Pt3(CO)6](n)2- (n = 2-5), in THF and acetonitrile. A combined in situ FTIR spectroscopic and BTEM study leading to the characterization of the new [H(4-x)Pt15(CO)19]x- (x = 2-4) clusters

The inter-conversions of platinum carbonyl dianionic clusters, ([Pt(3)(CO)(6)](n)(2-), n = 2-5), have been studied in THF and acetonitrile using in situ FTIR spectroscopy. These inter-conversions were facilitated by the addition (or removal) of molecular hydrogen. The individual reactions, namely reductions and oxidations of [Pt(3)(CO)(6)](n)(2-) were fast and reversible. BTEM analysis of the data provided the pure component spectra of the individual species without the need for physical separation. It is shown, for the first time, that the species [Pt(3)(CO)(6)](n)(2-) (n = 2) can be formed from the reduction of [Pt(3)(CO)(6)](n)(2-) (n = 3-5) by hydrogen alone in acetonitrile. Also, detection of dissolved CO(2) in solution suggests that a room-temperature water gas shift reaction occurs. This has been shown to arise from nucleophilic attack of water on a coordinated CO of [Pt(3)(CO)(6)](n)(2-) which leads to the formation of [HPt(15)(CO)(19)](3-) and [H(2)Pt(15)(CO)(19)](2-). The parent tetraanion, [Pt(15)(CO)(19)](4-), has been isolated in high yields by reaction of [Pt(3)(CO)(6)](n)(2-) (n = 2, 3) with NaOH at 60 °C and has been structurally characterized by X-ray analysis.     

Isolation of (CO)1- and (CO2)1- radical complexes of rare earths via Ln(NR2)3/K reduction and [K2(18-crown-6)2]2+ oligomerization

Deep-blue solutions of Y(2+) formed from Y(NR(2))(3) (R = SiMe(3)) and excess potassium in the presence of 18-crown-6 at -45 °C under vacuum in diethyl ether react with CO at -78 °C to form colorless crystals of the (CO)(1-) radical complex, {[(R(2)N)(3)Y(μ-CO)(2)][K(2)(18-crown-6)(2)]}(n), 1. The polymeric structure contains trigonal bipyramidal [(R(2)N)(3)Y(μ-CO)(2)](2-) units with axial (CO)(1-) ligands linked by [K(2)(18-crown-6)(2)](2+) dications. Byproducts such as the ynediolate, [(R(2)N)(3)Y](2)(μ-OC≡CO){[K(18-crown-6)](2)(18-crown-6)}, 2, in which two (CO)(1-) anions are coupled to form (OC≡CO)(2-), and the insertion/rearrangement product, {(R(2)N)(2)Y[OC(═CH(2))Si(Me(2))NSiMe(3)]}[K(18-crown-6)], 3, are common in these reactions that give variable results depending on the specific reaction conditions. The CO reduction in the presence of THF forms a solvated variant of 2, the ynediolate [(R(2)N)(3)Y](2)(μ-OC≡CO)[K(18-crown-6)(THF)(2)](2), 2a. CO(2) reacts analogously with Y(2+) to form the (CO(2))(1-) radical complex, {[(R(2)N)(3)Y(μ-CO(2))(2)][K(2)(18-crown-6)(2)]}(n), 4, that has a structure similar to that of 1. Analogous (CO)(1-) and (OC≡CO)(2-) complexes of lutetium were isolated using Lu(NR(2))(3)/K/18-crown-6: {[(R(2)N)(3)Lu(μ-CO)(2)][K(2)(18-crown-6)(2)]}(n), 5, [(R(2)N)(3)Lu](2)(μ-OC≡CO){[K(18-crown-6)](2)(18-crown-6)}, 6, and [(R(2)N)(3)Lu](2)(μ-OC≡CO)[K(18-crown-6)(Et(2)O)(2)](2), 6a.