Structural Investigation of Langmuir-Blodgett Films on Self-Assembly Modified Au Substrates

To improve the homogeneity and stability of single-layer azobenzene LB films on gold, self-assembled monolayers (SAMs) of terminally substituted alkyl thiol, HS(CH₂)₂-X(X=NH2,OH, COOH and CH₂SO₃Na, respectively), were used to modify the substrates before LB film deposition. It was found that single-layer C₈C₃ LB films on these modified substrates were more uniform and stable. Reflecion-Absorption(RA) FTIR measurements on these films indicated that at the LB/SAMs interface, ionic bonds. have formed for the modification with -NH₂ while hydrogen bonding occurred for modifications with -OH. -COOH and -SO₃Na,respectively. It can be concluded that the ionic or hydrogen bonding at the LB/SAM interface is responsible for the improvement in homogeneity and stability. It was believed that the less defected films after the time aging were most probably due to the ionic bond and hydrogen bonding mentioned above.     

Tricarbonylrhenium(I) complexes of phosphine-derivatized amines, amino acids and a model peptide: structures, solution behavior and cytotoxicity

Modified Mannich reactions of amines, amino acids and a model peptide with Ph₂PH and CH₂O gave bis(diphenylphosphinomethyl)amines (Ph₂PCH₂)₂NR [R=Ph (1), CH₂CH₂OH (2), CH₂COOCH₂Ph (3), CH₂CONHCH₂COOCH₂Ph (4), CH₂COOH (5)] and (Ph₂PCH₂)₂NCH₂CH₂N(CH₂PPh₂)₂ (6). Reaction with [ReBr₃(CO)₃]²⁻ under mild conditions led to [ReBr(CO)₃]{(Ph₂PCH₂)₂NR} [R=Ph (7), CH₂CH₂OH (8), CH₂COOCH₂Ph (9), CH₂CONHCH₂COOCH₂Ph (10), CH₂COOH (11)] and [ReBr(CO)₃(Ph₂PCH₂)₂NCH₂]₂ (12). All new complexes have been characterized by NMR and IR spectroscopy and for 7, 9 and 10, single-crystal X-ray diffraction analyses. Electrospray mass spectrometric studies show that the rhenium–phosphine chelates are very stable, especially in neutral methanolic solution. Hydrolysis of the ester and amide linkages slowly occur in acidic and basic solutions over several weeks; displacement of the bromide ligand also occurs in basic medium. Cytotoxicity testing of 7–10 and 12 showed that all the complexes are active against specific tumor cell lines, especially MCF-7 breast cancer and HeLa-S³ suspended uterine carcinoma.     

Unexpected structural analogy between early and late 3d transition metal alkoxide carboxylates: Synthesis and single crystal X-ray study of Ni6(OH)2(OR)6(OCOR)2, R = C2H4NMe2, R = H, CH3

Modification of the liquid Ni(OR^N)₂, R^N = C₂H₄NMe₂, with stoichiometric or sub-stoichiometric amounts of carboxylic acids, HCOOH or CH₃COOH, results in formation of crystalline heteroleptic complexes Ni₆(OH)₂(OR^N)₆(OCOR)₂, R = H (1), CH₃ (3) with the core structure closely analogous to that observed earlier for hexanuclear titanium (IV) alkoxide carboxylates and derived from hexagonal packing of the donor atoms.     

Oxidation of non-activated C---H bonds in hydrocarbons and steroids

CrO₃ in CH₂Cl₂/CH₃COOH/(CH₃CO)₂O oxidizes hydrocarbons to alcohols and ketones, 5-androstane and 3β-acetoxy-5-androstane are converted to 5-androst-14-en-16-ones.     

Hydrolysis and polycondensation of ethyl silicates. 1. Effect of pH and catalyst on the hydrolysis and polycondensation of tetraethoxysilane (TEOS)

The effect of pH and of catalysts on the course of the hydrolysis and condensation of tetraethoxysilane (TEOS) in water—ethanol solution was studied with the aid of chromatography, potentiometry and gelation tests. Strong acids (HCl, HClO₄, HNO₃, H₂SO₄, p-toluenesulphonic acid), weak acids (Cl₃CCOOH, (COOH)₂, ClCH₂COOH, CH₃COOH, HCOOH) and LiOH were used as catalysts. The rate of hydrolysis depended on the pH of the solution and not on the chemical structure of the catalyst. The hydrolysis was both acid and base catalysed and its rate was at a minimum at pH 7.0.

The rate of condensation of the reaction products of the hydrolysis of TEOS (water—ethanol solutions of ethoxyhydroxysiloxanes) was at a minimum at a pH of about 2.0. The condensation was both acid and base catalysed and was markedly accelerated by both HF and H₃PO₄.     

Ion scattering and X-ray photoelectron spectroscopy of copper overlayers vacuum deposited onto mercaptohexadecanoic acid self-assembled monolayers

Metal overlayers deposited in vacuum onto self-assembled monolayer (SAM) systems serve as models for more complex metalized polymers. Metals (M) deposited onto SAMs with different organic functional end groups exhibit a wide range of behavior, ranging from strong chemical interactions with the end group to complete penetration of the metal through the SAM. In this work, we have characterized the interactions of Cu with the ---COOH of mercaptohexadecanoic acid (MHA, HOOC(CH₂)₁₅SH) SAMs self assembled on gold films by using X-ray photoelectron spectroscopy (XPS) to examine the chemical interactions, and a combination of XPS and ion scattering spectroscopy (ISS) to deduce the growth mode and penetration rate of the deposited Cu. We found that submonolayer amounts of Cu react with HOOC, whereas the rest of the Cu remains metallic and penetrates beneath the SAM surface to the SAM  Au interface. Considerable amounts of Cu (5 nm or more) will penetrate beneath the SAM layer, which is ca. 2.5 nm thick, despite the submonolayer presence of Cu at the SAM surface. The penetration rate depends strongly on the Cu deposition rate. Depositing copper onto MHA at 220 K or less, or using faster Cu deposition rates, results in slower or even completely suppressed penetration of the Cu through the SAM layer, whereas exposure to X-rays greatly enhances the penetration rate of large amounts of Cu through the SAM layer. The reacted copper is, based on the XPS 2p and LMM peaks, in the +2 oxidation state, but cannot be identified with a simple, stoichiometric oxide such as Cu₂O, CuO, or Cu (OH)₂.     

胜利褐煤Ca~(2+)负载量对其平衡复吸水含量的影响

以胜利褐煤为研究对象,利用XRF、FT-IR等手段,采用灰分、pH值、不同相对蒸气压下的复吸水含量等参数,研究了Ca2+的离子效应对褐煤在不同相对蒸气压下复吸水含量的影响。研究结果表明,煤中Ca2+的负载量随用于交换的钙离子溶液浓度的增大而增加。煤中Ca2+的负载量对煤样的平衡复吸水含量影响较大,Ca2+负载量越大,煤样的平衡复吸水含量越大。相对蒸气压高于92%平衡复吸水含量的主要控制因素为游离水分子与游离水分子之间的相互作用力。相对蒸气压在11%~92%平衡复吸水含量的主要控制因素为金属水簇Ca+(H2O)n与毛细管之间的毛细管作用力。     

分子自组装法制备具有可控浸润性的铜表面

通过简单浸泡的方法在铜基底上制备出了具有微纳米复合结构的氧化铜, 再利用混合硫醇溶液[含HS(CH₂)₉CH₃和 HS(CH₂)₁₁OH]对浸泡后的表面进行修饰, 通过控制溶液中HS(CH₂)₁₁OH的浓度, 制备出一系列具有不同浸润性的铜表面, 实现表面从超疏水到超亲水的有效调控. 研究发现, 表面浸润的可控性源于表面复合结构与不同化学组成的协同作用, 微纳米复合结构的存在为表面浸润性的调节提供了必要的条件.     

Theoretical interpretation of the infrared lineshape of liquid and gaseous acetic acid

We have applied a model used recently [P. Blaise, M.J. Wojcik, O. Henri-Rousseau, J. Chem. Phys. 122 (2005) 64306] to unpolarized ν_X–H infrared lineshapes of cyclic (CH₃COOH)₂ in liquid and gaseous phases and (CD₃COOH)₂ in gaseous phase and taking into account the IR A_g forbidden transition. This model incorporates (i) the anharmonic coupling between the high frequency mode and the H-bond bridge, (ii) the Davydov coupling between the excited states of the two moieties, (iii) the quantum direct and indirect dampings. The approach reproduces satisfactorily the main features of the experimental lineshapes by using a minimum number of independant parameters.     

单个MoS2纳米片氢析出催化特性研究

MoS₂作为高效的电催化氢析出(HER)催化剂已有大量文献报道. 实验和DFT计算结果都表明MoS₂的高氢析出活性来源于边缘,而其基面是催化惰性的。为了进一步验证此结论,本文利用巯基羧酸在恒电位下自组装单层修饰的纳/微米电极固定不同尺寸的单个纳米片状,对MoS₂氢析出催化活性与其尺寸的关系进行研究,发现纳米片状MoS₂具有较高的催化活性,同时较小尺寸的MoS₂氢析出活性更高,说明MoS₂的边缘的增多对其催化活性有巨大提升,即证明了边缘部分具有更高的氢析出催化活性.     

Mononuclear Pt(II) and Pd(II) 1,4-dithiolato complexes. Crystal structures of [Pt((−) DIOS) (PPh3)2] and [Pd(S(CH2) 4S)(Ph2P(CH2) 3PPh2)]. Application in styrene hydroformylation

Addition of 1,4-dithiols to dichloromethane solutions of [PtCl₂(P-P)] (P-P = (PPh₃)₂, Ph₂P(CH₂)₃PPh₂, Phd₂P(CH₂)₄PPh₂; 1,4-dithiols = HS(CH₂)₄SH, (−)DIOSH₂ (2,3-O-isopropylidene-1,4-dithiol-l-threitol), BINASH₂ (1,1′-dinaphthalene-2,2′-dithiol)) in the presence of NEt₃ yielded the mononuclear complexes [Pt(1,4-dithiolato)(P-P)]. Related palladium(II) complexes [Pd(dithiolato)(P-P)] (P-P=Ph₂P(CH₂)₃PPh₂, Ph₂P(CH₂)₄PPh₂; dithiolato = ⁻S(CH₂)₄S⁻, (−)-DIOS) were prepared by the same method. The structure of [Pt((−)DIOS)(PPh₃)₂] and [Pd(S(CH₂)₄S)(Ph₂P(CH₂)₃PPh₂)] complexes was determined by X-ray diffraction methods. Pt—dithiolato—SnC1₂ systems are active in the hydroformylation of styrene. At 100 atm and 125°C [Pt(dithiolate)(P-P)]/SnCl₂ (Pt:Sn = 20) systems provided aldehyde conversion up to 80%.     

醋酸钯和四氯对苯醌催化氧化低浓度煤矿瓦斯制甲醇

利用自制的实验系统进行了醋酸溶液中低浓度瓦斯催化氧化制甲醇研究。实验结果表明,以Pd(OAc)₂为催化剂,反应体系中添加对苯醌或四氯对苯醌可改善甲烷活化环境,四氯对苯醌对瓦斯催化氧化过程的作用效果好于对苯醌。四氯对苯醌用量、反应压力和反应温度对瓦斯催化氧化具有重要影响。甲醇生成量随四氯对苯醌用量、反应压力和反应温度升高而增加。CH₃OH是通过反应过程中产生的H₂O₂与CH₄相互作用形成的。CH₃COOCH₃一部分是由Pd²⁺直接氧化CH₄得到的;另一部分是由CH₃OH与反应溶剂CH₃COOH通过酯化反应形成的。     

Preparation and X-ray characterization of two-coordinate Cu(I) complex of aliphatic thiolato ligand: Effect of steric bulk on coordination features

We have synthesized in a single-step procedure from available copper(I) precursor at RT two Cu(I) thiolato clusters of the formula [Cu₄(μ-SCH(CH₃)₂)₆]²⁻ and [Cu₅(μ-SC(CH₃)₃)₆]⁻ as revealed by X-ray crystallography, where increased steric bulk leads to a bigger cage with some two-coordinate metal centers. In addition, we identified a mononuclear two coordinate thiolato complex with the bulkier ligand, of the formula NEt₄[Cu(SC(CH₃)₃)₂]. This is only the second example of such a complex of an aliphatic ligand that is structurally characterized. The X-ray structure reveals an S–Cu–S angle of 176.7–179.5°, with Cu–S distances of 2.14 Å.     

Studies on α-Methacrylate Copper(Ⅱ) Complexes with Imidazole

Two complexes of α-methacrylate copper(Ⅱ) with imidazole, Cu[CH₂=C(CH₃)COO]₂· (imH)₂(1) and Cu ₂[CH₂C(CH₃)COO]₄(imH)₂(2) were prepared and characterized. The single crystal X-ray diffraction study of complex 1 showed that the copper(Ⅱ) atom in the symmetric centre of the square planar environment was coordinated by two monodentate α methacrylate groups and two imidazole ligands that were in trans position with each other. Each molecular unit is linked with four neighbouring units by means of hydrogen bond interactions, forming a two-dimensional supermolecular compound( d_N…O =0.278 1 nm). Complex 1 crystallizes in monoclinic, space group P2₁/n with a =1.023 94(12) nm, b =0.842 94(8) nm, c =1.079 35(10) nm, β=117.231(7)°, Z =2. The forming mechanism of the complexes was discussed.     

New heterometallic copper zinc alkoxides: synthesis, structure properties and pyrolysis to Cu/ZnO composites

The copper compound [(THF)KCu(O^tBu)₃]_∞ 1 was obtained by interaction of a 1:1 mixture of ZnCl₂/CuCl₂ with KO^tBu. Bi- and trifunctional aminoalcohols were used to synthesize the intramolecularly donor stabilized Cu(II) alkoxides Cu(OCH(R)CH₂NMe₂)₂ (3: R=Me, 4: =CH₂NMe₂) where 4 was structurally characterized. Lewis acid–base adduct formation with (Me₃Si)₃CZnCl gave the heterodinuclear compounds (Me₃Si)₃CZnCl · Cu(OCH(R)CH₂NMe₂)₂ (5: R=Me, 6: R=CH₂NMe₂), which were characterized by X-ray single-crystal structure analysis. The two metal centers Cu and Zn of 5 and 6 are bridged by two oxygen atoms to form a Cu–O–Zn core. Pyrolysis of compounds 5 and 6 in dry argon or a H₂/N₂ mixture at atmospheric pressure forms metallic copper and zinc oxide, whereas pyrolysis under O₂/Ar forms additionally oxidized copper species. Elemental analysis of the pyrolysis products showed carbon and nitrogen contamination. Scanning electron microscopy and energy dispersive X-ray analysis were performed to get information on the morphology and the chemical composition of the pyrolysis products.     

Studies on the Halogen Substituted β-Amino Acids and Their Cu(Ⅱ) Coordination Complexes in Crystallography

Halogen substituted β-amino acids, D,L-3-amino-3-(4-fluoro)phenylpropionic acid(D,L-HL1, 1) and D,L-3-amino-3-(4-bromo)phenylpropionic acid(D,L-HL2, 2), as well as their Cu(Ⅱ) coordination complexes[Cu(L1)₂(CH₃OH)₂]·2CH₃OH(3) and[Cu(L2)₂(CH₃OH)₂]·2CH₃OH(4) were investigated and their single crystal structures were discussed in details. Supramolecular helical chains were found in β-amino acids 1 and 2 while there was no helix in their coordination complexes 3 and 4. The formation of supramolecular helixes could be due to the hydrogen bonds between terminal-NH³⁺ and adjacent-COO^- in β-amino acids 1 and 2. While, this kind of hydrogen bonds could not be observed in their Cu(Ⅱ) coordination complexes 3 and 4, in which central-symmetrical dimers could be formed via coplanar coordinated bonds(N-Cu-O) between-NH₂ and-COO^-.     

A highly stable and luminescent mononuclear Cu(I) bis-{5-tert-butyl-3-(6-methyl-2-pyridyl)-1H-1, 2, 4-triazole} complex

A new emissive mononuclear homoleptic Cu(I) complex of 5-tert-butyl-3-(6-methyl-2-pyridyl)-1H-1,2,4-triazole (bmptzH),[Cu(bmptzH)₂](ClO₄) (1), has been synthesized by treatment of [Cu(PPh₃)₂(CH₃CN)₂](ClO₄) or[Cu(CH₃CN)₄](ClO₄) with the bmptzH ligand. It is revealed that complex 1 displays a distorted N₄ tetrahedral arrangement formed by two bmptzH chelates, in which bmptzH adopts a neutral bidentate chelating coordination mode using the N atom of the pyridyl ring and the 4-N not 2-N atom of the 1,2,4-triazolyl ring. It is shown that complex 1 is highly stable and exhibits good luminescence properties in solution and solid states at room temperature due to the introduction of a methyl group at the ortho-position of the pyridyl ring.     

Chemie polyfunktioneller moleküle : LXXXVII. Synthese und reaktionsverhalten von 4-methyl-1,2,6-tristiba-tricyclo[2.2.1.0]heptan (Sb3-nortricyclan) gegenüber chrom-, molybdän- und wolframhexacarbonyl

The reaction of CH₃C(CH₂Cl)₃ and NaSb(C₆H₅)₂ in liquid ammonia leads to Sb₂(C₆H₅)₄ (I). Using CH₃C(CH₂Br)₃ instead of CH₃C(CH₂Cl)₃ results in the formation of I and CH₃C[CH₂Sb(C₆H₅)₂]₃ (II). Treatment of II with gaseous HCl in dry CH₂Cl₂ yields CH₃C(CH₂SbCl₂)₃ (III) under elimination of benzene. The reduction of III with Na in THF gives the first all-cis-organocyclotristibane (Sb₃-nortricyclane) CH₃C(CH₂Sb)₃ (IV) which forms the new CH₃C(CH₂Sb)₃M(CO)₅ complexes (Va---Vc) with M(CO)₅THF (M = Cr, Mo, W).     

Structural tuning of coordination polymers by 4-connecting metal node and secondary building process

Due to variation in ligand's conformation, metal node's connecting geometry, and secondary building process by anions, bat-like, dumbell-like, diamondoid, or pillar-layer topologies are achieved.     

多碳醇类化合物的合成

本文由正-二十四烷酸与五氯化磷反应,得到的二十四烷酰氯在氯仿中和三乙胺存在下与1-吗啉-1-环己烯反应所得中间体,经酸性水解,碱性开环和酸化,得到7-氧代-三十烷酸,而据文献报导[7],正-二十四烷酞氯与1-吗啉-1-环己烯反应结果,得到的仍然是原料二十四烷酸。作者采用上述方法合成了五种新的7-氧代烷酸R-C(=O)-(CH²)⁵-COOH(R=n-C₁₄H₂₉,n-C₁₆H₃₃,n-C₁₈H₃₇,n-C₂₁H₄₃和n-C₂₃H₄₇)。所制得的7-氧代三十烷酸经黄鸣龙改良的开息纳尔-武尔夫还原,再经四氢锂铝还原,即得三十烷醇。