Synthesis and reactions of 4-vinyl pyridine derivatives of ruthenium(II)

4-Vinyl pyridine (4-Vp) reacts with RuHClCO(PPh₃)₃ (I) in THF to give RuHClCO(PPh₃)₂(4-Vp) (II, which reacts with sodium derivatives of bidentate chelating ligands to afford substitution products, [RuH(CO)(PPh₃)₂(L)]. The bindentate ligands used are 2-hydroxybenzaldehyde, 2-hydroxy-3-methoxybenzaldehyde, trifluorothenoylacetone and 8-hydroxyquinoline. Insertion reactions of the Ru---H bond of II with activated olefins such as acrylonitrile [giving RuCl(CO)(CH₃CHCN)(PPh₃)₂(4-Vp)], 2-vinyl pyridine, dimethyl fumarate and monobromodiethyl fumarate have been carried out to obtain chelated Ru---C bonded complexes. RuCl₂(PPh₃)₃ reacts with an excess of 4-Vp to give an octahedral ruthenium addition complex containing two vinyl pyridine ligands. The dimer [RuClCO(CH₃CHCN)(PPh₃)(4-Vp)]₂ is obtained by the reaction of [RuClCO(CH₃CHCN)(PPh₃)₂]₂ with an excess of 4-Vp. Stereochemical assignments have been made for these new complexes on the basis of IR and ¹H NMR data.     

Adsorption of pyridine on the Lewis acid sites of microcrystalline γ-alumina: a quantum chemical cluster model study

Adsorption of pyridine on Lewis acid sites of microcrystalline γ-alumina was studied by quantum chemical cluster model approach at B3LYP and HF/6-31++G(d,p) levels of theory considering both the standard and the counterpoise-corrected potential energy surfaces (PESs). Harmonic vibrational frequency shifts of pyridine ν₈ and ν₁₉ internal mode components calculated at both levels of theory seem to excellently reproduce the experimental observations, the results for standard and counterpoise-corrected PESs being essentially identical. The interaction energies of pyridine with various clusters representing microcrystalline γ-Al₂O₃ were also calculated and the natural bond orbital and atoms in molecules analyses were performed.     

Copper(II), nickel(II) and cobalt(II) complexes of 4-cyanobenzonic acid: syntheses, crystal structures and spectral properties

Three new metal complexes, Cu(4-Hcba)₂(4-cba)₂(Py)₂ (4-Hcba=4-cyanobenzoic acid) 1 and M[H(4-cba)₂]₂(Py)₂ (M=Ni 2, Co 3), have been prepared by the treatment of 4-Hcba with the respective metal nitrate M(NO₃)₂ (M=Cu, Ni, Co) in the presence of pyridine (Py). Single-crystal X-ray diffraction analyses (3 is isostructural to 2) show that the obtained complexes are of isolated mononuclear and the metal atoms have distorted octahedral coordination environment. Two different types of intramolecular hydrogen bonds exist: asymmetrical O–HO for 1 and symmetrical OHO for 2 and 3. The crystal packing between the molecular complexes is controlled mainly by T-shaped C–Hπ interactions between pyridine and phenyl rings. Preliminary discussions on IR, UV–VIS and fluorescent spectra have also been carried out.     

Synthesis,properties and application of novel 5,6,5,6-tetracyclic pyrazine/pyrrole-fused unsymmetric bis(BF2) fluorescent dyes: BOPYPYs

Novel 5,6,5,6-tetracyclic pyrazine/pyrrole-fused unsymmetric bis(BF₂) fluorescent dyes (BOPYPYs) were synthesized by reaction of pyrrole-2-carboxaldehyde with 1-(pyrazin-2-yl) hydrazine in the presence of Et₃N-BF₃·Et₂O for the first time.     

波浪形一维链状镉配合物的合成、结构及分子识别性能

以四水合硝酸镉(Cd(NO_3)_2·4H_2O)与2-(邻溴)苯基-4,5-咪唑二羧酸(o-BrPhH_3IDC)和草酸铵通过水热反应,合成了一个波浪形一维链状配合物{[Cd(o-BrPhH_2IDC)_2(H_2O)]·H_2O}_n(1)。并通过元素分析、傅里叶变换红外光谱、热重分析和单晶X射线衍射等技术手段对配合物1进行了表征。结果表明,配合物1为正交晶系,Pbca空间群。配合物1在316 nm波长激发下,在356 nm处有最大的荧光发射峰。配合物1对小分子具有识别性能,乙腈使配合物荧光强度明显增强,甲醇、乙醇使配合物荧光强度明显减弱,而吡啶处理后的样品在356 nm附近的发射峰消失,显示对吡啶有识别作用。     

RCOO-取代的镍(Ⅱ)配合物单组分高效催化乙烯均聚和共聚反应

合成并表征了含RCOO-基团的单核(Ni¹~Ni²)及双核(Ni³)镍配合物[(2,6-R₂-C₆H₃)—N=C(H)—(3-Ph-5-PhCOO-2-O-C₆H₂)-κ²-N,O]Ni(CH₃)(pyridine)](R=iPr;3,5-tBu₂C₆H₃),并用于催化乙烯均聚和共聚反应。 作为单组分催化剂,这些配合物可以有效地催化乙烯聚合得到中等相对分子质量的支化聚乙烯(PE)。 供电性的PhCOO—基团促进了催化剂Ni¹的引发,从而在低温下比Ni⁰活性更高。 引入大位阻的2,6-(3,5-二叔丁基苯基)苯胺基团,催化剂Ni²在5×10⁵ Pa下的活性高达1.8×10⁶ g PE mol^-1·Ni^-1·h^-1,是活性最高的水杨醛亚胺中性镍催化剂之一。 与相应的单核催化剂相比,双核催化剂Ni³对三苯基膦具有更好的耐受性。 这些催化剂可催化乙烯与1,5-己二烯、1,7-辛二烯、6-溴-1-己烯或10-十一烯酸甲酯的共聚合,制备功能化聚乙烯。     

Structural varieties in double salts of silver acetylide containing ancillary anions and terminal ligands

New double salts Ag₂C₂·6AgO₂CCHF₂ (1), [HPyCH₂OH][Ag₉(C₂)(CF₃CO₂)₉(HPyCH₂OH)(H₂O)]·0.5H₂O (PyCH₂OH=4-(hydroxymethyl)pyridine) (2), Ag₂C₂·5CF₃SO₃Ag·2MeCN·2H₂O (3) and Ag₂C₂·8CF₃SO₃Ag·2EtCN·3H₂O (4) have been synthesized by dissolving Ag₂C₂ in an aqueous solution of the corresponding silver salt followed by the addition of an ancillary ligand. Complex 1 has a three-dimensional structure in which unprecedented basket-like silver cages are inter-connected by difluoroacetate ligands. In 2, centrosymmetric (C₂)₂@Ag₁₄ double cages with each half taking the shape of a triangulated dodecahedron are linked through additional silver atoms to generate an infinite chain, and unsupported silver(I)–silver(I) interactions exist between neighboring chains. Of the two independent 4-(hydroxymethyl)pyridinium ions in 2, one acts in the O-ligating mode, which is observed for the first time, while the other merely serves to provide charge balance and space-filling. Both 3 and 4 are layer-type structures in which the basic building unit is a distorted monocapped octahedron and monocapped trigonal prism, respectively.     

Au@SiO2膜/Ti电极吸附吡啶的表面增强拉曼光谱研究

基于壳层隔绝纳米粒子增强拉曼光谱技术,合成了Au@SiO₂纳米粒子,并对其进行了相关表征. 结果表明,包裹的二氧化硅层连续、致密,Au@SiO₂膜/Ti电极上可获得金属钛电极上吸附吡啶分子的高质量表面增强拉曼光谱（SERS）信号. 通过Pt、Ni电极的测试,证实该信号源于吸附在基底表面的吡啶分子. 此外,Au@SiO₂膜/Ti电极上吸附吡啶分子的现场SERS光谱研究表明,在-0.1 V ~ -0.6 V电位区间,吡啶分子平躺吸附,从-0.6 V起吸附的吡啶分子由平躺逐转变为垂直,而当电位为-1.2 V时,电极表面析氢,吡啶脱附.     

Reactivity of carbon monoxide towards high valent molybdenum complexes

Reaction of carbon monoxide (3 atm) with Mo(O)₂(mes)₂ (mes = MESITYL = C₆H₂Me₃-2,4,6) in pyridine at room temperature affords dimesityl ketone 1 (5%) and 1,1′-bis(mesitoyl)-1,1′,4,4′-tetrahydro-4,4′-bipyridine 2 (25%), the molecular structure of which has been determined by an X-ray diffraction study. The formation of 2 represents the first example of N-acylation of a pyridine by CO mediated by a transition metal complex. It has been shown that the relative ratio of 1 and 2 is dependent on the reaction conditions and that the presence of pyridine is essential for the formation of 1. Reactions of CO with the isoelectronic complex Mo(N^tBu)₂mes₂ contrast sharply with Mo(O)₂mes₂ and, under the same conditions, no dihydropyridine is formed, the sole identified products being 1 (60%) and mesityltertiobutyl amide HN(^tBu)COmes (40%). In light of the experimental results and of extended Hückel calculations on dioxo and diimido d⁰ molybdenum complexes, a tentative mechanism for the formation of 2 is proposed which involves oxycarbene-like intermediates in the case of the more electrophilic dioxo molybdenum species.     

Luminescent rhenium(I) polypyridine fluorous complexes as novel trifunctional biological probes

We present the synthesis, characterization, and photophysical properties of three luminescent rhenium(I) polypyridine fluorous complexes [Re(Me(2)bpy)(CO)(3)(L)](PF(6)) (Me(2)bpy = 4,4'-dimethyl-2,2'-bipyridine; L = 3-amino-5-(N-((3-perfluorooctyl)propyl)aminocarbonyl)pyridine (py-Rf-NH(2)) (1), 3-isothiocyanato-5-(N-((3-perfluorooctyl)propyl)aminocarbonyl)pyridine (py-Rf-NCS) (2), 3-ethylthioureidyl-5-(N-((3-perfluorooctyl)propyl)aminocarbonyl)pyridine (py-Rf-TU-C(2)H(5)) (3)). The isothiocyanate complex 2 has been used to label bovine serum albumin (BSA) and glutathione (GSH). The photophysical properties of the resultant bioconjugates have been studied. The isolation of the luminescent fluorous rhenium-GSH conjugate from a mixture of 20 amino acids has been demonstrated using fluorous solid-phase extraction (FSPE). Additionally, the cytotoxicity of complexes 1 and 3 toward HeLa cells has been examined by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide (MTT) assay. The cellular uptake properties of complex 3 have also been investigated by laser-scanning confocal microscopy.     

不同晶体结构MnO2纳米催化剂低温NH3-SCR性能研究

为了探究催化剂的结构和催化活性的关系,采用水热法制备了四种不同晶体结构的MnO₂纳米催化剂（α-MnO₂、β-MnO₂、γ-MnO₂和δ-MnO₂）,并考察了其低温NH₃-SCR活性。结果表明,不同晶体结构催化剂的活性不同,依次为γ-MnO₂ > α-MnO₂ > β-MnO₂ > δ-MnO₂,γ-MnO₂表现出最高的催化活性,NO_x转化率在150-260℃超过90%。随后,通过X射线衍射（XRD）、扫描电子显微镜（SEM）、N₂吸附-脱附、热重（TG）、红外光谱（FT-IR）、程序升温还原（H₂-TPR）及吡啶吸附红外光谱（Py-FTIR）等表征手段对催化剂的结构和性质进行分析。结果表明,α-MnO₂和β-MnO₂为纳米棒,γ-MnO₂和δ-MnO₂为纳米针,催化剂的比表面积并不是影响低温NH₃-SCR活性的主导因素。γ-MnO₂具有适宜的孔道结构、较强的氧化还原能力、丰富的化学氧含量和Lewis酸酸性位点,是其具有最高低温NH₃-SCR活性的原因。     

Reactions of Lewis bases with tetrakisdiphenylamide uranium(IV)

The coordinatively unsaturated uranium(IV) complex U[N(C₆H₅)₂]₄ has been prepared via the stoichiometric reaction of diphenylamine with [(Me₃Si)₂N]₂ H₂. U[N(C₆H₅)₂]₄ coordinates Lewis bases such as Et₂O, THF, pyridine or (EtO)₃PO, based on electronic absorption spectroscopy and ¹H NMR studies. Exchange between U[N(C₆H₅)₂]₄ and U[N(C₆H₅)₂]₄(L), where L is THF or pyridine, is rapid on the NMR time-scale between 307 and 323 K. Measurement of equilibrium constants for L = THF provides ΔH and ΔS values of −60 kJ mol⁻¹ and −1.8 × 10² J K⁻¹ mol⁻¹, respectively. U[N(C₆H₅)₂]₄ coordinates and binds (EtO)₃PO much more tightly (K_eq = & > 10⁴ M⁻¹) than THF or pyridine with the exchange rate between U[N(C₆H₅)₂]₄ and U[N(C₆H₅)₂]₄[OP(OEt)₃] being close to the NMR time-scale.     

Fluorous phase-transfer activation of catalysts: application of a new rate-enhancement strategy to alkene metathesis

Reactions of the bis(pyridine) complex (H2IMes)(Py)2(Cl)2Ru(=CHPh) and fluorous phosphines P(CH2CH2R(fn))3 (n = a, 6; b, 8; c, 10; R(fn) = (CF2)(n-1)CF3) give (H2IMes)(P(CH2CH2R(fn))3)(Cl)2Ru(=CHPh) (2a-c, 64-73%), which are analogs of Grubbs' second generation catalyst and effective alkene metathesis catalysts under organic monophasic and fluorous/organic biphasic conditions. The latter give rate accelerations, which are believed to arise from phase transfer of the dissociated fluorous phosphine.     

三嗪-吡唑钌配合物的合成、结构及光催化活性

光催化具有无污染、安全高效等优点,已成为环保领域的研究热点。 本文选择2,4-二(3,5-二甲基吡唑)-6-二乙基胺-1,3,5-三嗪(L₁)和2, 6-二[3-(5-甲基吡唑基)]吡啶(L₂)为配体、以RuCl₃为金属源,合成了3种配合物[Ru(L₁)Cl₃](1)、[Ru(L₂)₂]·Cl₃(2)和[Ru(L₂)₂]·(H₂BTC)·(HBTC)·H₂O(3),同时进行了IR、UV-Vis、TG及X射线衍射等表征,并对配合物在光催化降解罗丹明B方面进行了探讨,结果表明,配合物13均具有一定程度的光降解效果,降解效果分别为46.8%、44.7%和40.4%。 相同条件下,加入H₂O₂后的配合物13的降解效果比金属盐、配体及H₂O₂单独存在时的降解效果好。     

Unambiguous cis-coordination of mono- and bi-dentate Lewis bases to Ni(SN)2 Schiff-base complexes derived from S-alkyl dithiocarbazate

The bidentate Schiff-base ligand, HL¹, prepared by condensation of equivalent molar amount of o-nitrobenzaldehyde with S-benzyl dithiocarbazate, yielded the neutral square-planar complex, NiL¹₂ (1) in the presence of Ni(OAc)₂·4H₂O. Addition of pyridine to (1) and phenanthroline (phen) to NiL (3) afforded the adducts NiL¹₂(py)₂·1.5H₂O (2) and NiL(phen) (4), respectively, where H₂L is a known quadridentate (NS)₂ ligand. Single crystal X-ray analysis of (2) and (4) showed that the pyridine rings and phen occupy cis-positions in the octahedral adducts. In both cases, one N–Ni bond in the parent Ni(NS)₂ complexes is severely perturbed, thus facilitating cis-addition of the Lewis bases. The present results together with those reported previously show that cis-addition is preferred in the addition reaction of Ni(NS)₂ Schiff-base complexes derived from S-alkyl dithiocarbazate. Addition of pyridine and 2,2′-bipyridine to NiL (3) is also discussed.     

NiP/SAPO-11催化脂肪酸甲酯加氢脱氧及产物的异构化

采用过量浸渍法制备了不同镍负载量的Ni P/SAPO-11催化剂,并用N2吸附-脱附、吡啶红外光谱、NH3-TPD、H2-TPR等技术对催化剂的物理化学性能进行了测试。脂肪酸甲酯催化加氢脱氧及产物异构化反应在固定床反应器上进行,液体产品分别用GC-MS和GC进行定性和定量分析。结果表明,在温度为340℃,压力为2.0 MPa,氢气流量为60 m L/min,重时空速为2.5 h-1的操作条件下,当Ni负载量为3%(质量分数)时,原料转化率可以达到97.8%,C15-18的收率84.5%,异构化率14.0%。     

The reaction of tetrahydridododecacarbonyltetrarhenium(0) with pyridine and some nitrogen-containing bases

The reactions of H₄Re₄(CO)₁₂ with some nitrogen-containing bases L in chloroform at room temperature were investigated. For L = pyridine, γ-picoline and piperidine, two types of products, namely [H₄Re₃(CO)₉L]⁻[LH]⁺ and H₃Re₃(CO)₉L₃, were isolated. When L = -picoline, 4-CN-pyridine, imidazole or 2,4-dimethylimidazole, [H₄Re₃(CO)₉L]⁻[LH]⁺ is the only product with a yield close to 75%. The structure of H₃Re₃(CO)₉L₃ (L = pyridine) (1) and [H₄Re₃(CO)₉L]⁻[LH]⁺ (L = -picoline) (3) were determined by the X-ray diffraction method. For 1, the three rhenium atoms form an equilateral triangle with edge-bridging hydrides. Each rhenium is coordinated by three carbonyl groups and an axial pyridine. The three pyridines are not all on the same side of the triangular plane to reduce the steric repulsion which is obvious from bond angles and distances data. In 3, the three rhenium atoms form an isosceles with two hydride-bridged Re---Re single bonds and an Re---Re double bond bridged by two hydrides. Each rhenium is coordinated by three CO groups, and -picoline is coordinated to rhenium in the axial position.     

Addition of a Reformatsky reagent to N-anthracene-9-sulfonyl and related imines: Synthesis of protected β-amino acids

The Reformatsky reagent tert-butoxycarbonylmethylzinc bromide adds in high yields to N-sulfonylimines, e.g. 1a–1d, derived by condensation of benzaldehyde dimethyl acetal with methanesulfonamide, toluene-4-sulfonamide, 4-(methoxycarbonyl)benzenesulfonamide and sulfamide: the products are protected β-amino acids 2a–2d. N-Deprotection occurs reductively (Na-naphthalene; low yields) for 2b and 2c or hydrolytically (refluxing aq. pyridine; 76% yield of amino acid 3a after acid hydrolysis of the t-butyl ester) for the sulfamide derivatives 2d. Anthracene-9-sulfonamide (6) is readily available by sulfonation and chlorination of anthracene, and condenses with aldehydes [RCHO; R = Ph, 4-FC₆H₄, 4-MeOC₆H₄, 4-NCC₆H₄, 2-furyl, (E)-styryl], e.g. in the presence of TiCl₄/Et₃N, to yield imines 7a–7f, which after addition of tert-butoxycarbonylmethylzinc bromide give protected amino acids 8a–8f; however, 8f cyclizes to the sultam 9 via a spontaneous intramolecular Diels-Alder reaction. Reductive cleavage of the N-anthracene-9-sulfonyl group is much easier than for traditional N-sulfonyl protecting groups, as demonstrated by the deprotection of 8a and 8c using aluminium amalgam.     

Etude des reactions de srn1—partie 10 : Action de sulfanions sur les halogenures d''aryle fonctionnalises. synthese directe de benzothiophenes et thienopyridines

Functionalized aromatic halides Ar₁XY (Ar₁ = C₆H₄, Y = OCH₃, CONH₂, CN, COCH₃, CHO, COC₆H₅) undergo S_RN1 reactions with sulphur anions ^-SR, either simple (R=C₂H₅, CH₂C₆H₅) or functionalized (R = (CH₂)₂OH, (CH₂)₂CO₂Et, CH₂CO₂Et). Products Ar₁YS^- formed from the fragmentation of the radical anion Ar₁YSR^- are related to the redox potential of the aryl moiety Ar₁Y and with the energy of the bond S-R. In the heterocyclic series (Ar₂ = pyridine, Ar₃ = quinoline) a similar relationship appears but a competitive S_N(Ar) reaction occurs for pyridine substrates bearing an electron withdrawing group. A direct synthesis of benzothiophen via S_RN1 reaction and an improved synthesis of thienopyridines based on the S_N(Ar) reaction are reported.     

Coordination-driven self-assembly of palladium(Ⅱ)-based metallacalixarenes as anion receptors using flexible pyridine-bridged diimidazole ligands

Two types of palladiu m(Ⅱ)-based metallacalixarenes[ML]²⁺and[ML₂]²⁺have been synthesized through coordination-driven self-assembly from a series of flexible pyridine-bridged diimidazole ligands[2,6-bis((1 H-imidazol-1-yl)methyl)pyridine(L¹),2,6-bis((1 H-benzo[d]imidazol-1-yl)methyl)pyridine(L²),2,6-bis((1 H-naphtho[2,3-d]imidazol-1-yl)methyl)pyridine(L³)],with palladium(II)-based building blocks[Pd(BF₄)₂(M¹-BF_4)and(tmeda)Pd(NO₃)₂(M²-NO₃)(tmeda=N,N,N',N'-tetramethyl-ethylenediamine)].All complexes were characterized by NMR spectroscopy(¹H NMR and¹³C NMR),mass spectrometry(CSIMS,ESI-HRMS)and elemental analysis.The single crystal X-ray diffraction analysis of[M¹L²_2](NO₃)₂,[M¹L³_2](NO₃)₂,[M¹L³_2](PF_6)_2 and[M~2 L³](NO₃)₂further confirmed the uniquely single bowl-shape and double bowl-shape structures.The anion binding properties within the metallacalixarenes as receptors were also investigated by NMR titration experiments in DMSO.