两种Cu(Ⅱ)配合物的合成和结构表征

选取1,9-二(2-氟代苯基)-2,5,8一三氮杂壬烷与铜(Ⅱ)的苯甲酸盐和硝酸盐,合成了两个新的配合物[Cu(C18H23F2N3)(C7H5O2)(H2O)](C7H5O2)·2(H2O)(1)和[Cu(C18H23F2N3)(NO3)2]·(H2O)1/2(2),并获得其单晶,测定了晶体结构.单晶衍射数据显示化合物(1)属三斜晶系Pi空间群,化合物(2)属单斜晶系Cc空间群.     

两种Cu(II)配合物的合成和结构表征(英文)

选取1,9—二(2—氟代苯基)—2,5,8—三氮杂壬烷与铜(Ⅱ)的苯甲酸盐和硝酸盐,合成了两个新的配合物[Cu(C18H23F2N3)(C7H5O2)(H2O)](C7H5O2)·2(H2O)(1)和[Cu(C18H23F2N3)(NO3)2]·(H2O)1/2(2),并获得其单晶,测定了晶体结构.单晶衍射数据显示化合物(1)属三斜晶系Pi空间群,化合物(2)属单斜晶系Cc空间群     

二(N~3-水杨酰吡啶-2-羰基氨基腙基-κ~3N~1,N~2,O)合镍(Ⅱ)·二甲基甲酰胺的合成与晶体结构(英文)

配合物[Ni(spa)2](Hspa=N3-水杨酰吡啶-2-羰基氨基腙)用Hspa与Ni(Ac)2.4H2O反应制备.标题化合物的单晶X射线研究表明,Ni原子是位于两个三齿配体中的吡啶氮原子,氨基腙上的氮原子和甲氨酰基中的氧原子配位的畸变八面体形式中.该晶体属三斜晶系,P1空间群;a=1.063 58(3)nm,b=1.193 80(3)nm,c=1.26 354(3)nm,α=70.109 0(10)°,β=81.722 0(10)°,γ=87.476 0°,V=1.492 87(7)nm3,Z=2,Mr=642.32(C29H29N9O5Ni),Dc=1.429g.cm-3,μ=0.705 mm-1,F(000)=668,对于I>2σ(I)的4 487个反射点,R=0.030 8,Rw=0.080 4.在晶体结构中,存在两个羟基的O—H…N分子内氢键,此外两个N—H…O分子间氢键连接相邻的配合物形成一条平行于c轴的链,另一个N—H…O分子间氢键连接溶剂DMF分子.     

[M(S-S)(N-N)]配合物分子内荷移跃迁性能及其影响因素研究

测量了新近合成的配合物[M(S-S)(N-N)]在溶剂吡啶、乙醇和氯仿中的电子吸收光谱,比较了二亚胺上不同取代基形成的镍配合物在DMSO和DMF中的电子吸收光谱.并从分子轨道理论角度探讨了这类配合物电子吸收光谱中主要谱带的电子跃迁特性.着重研究了标题配合物分子内配体间荷移跃迁吸收带(LL'CT)与配合物构型、中心离子、配体取代基电子效应和溶剂极性之间的内在本质关系.     

Buckminsterfullerenes: a non-metal system for nitrogen fixation

In all nitrogen-fixation processes known so far--including the industrial Haber-Bosch process, biological fixation by nitrogenase enzymes and previously described homogeneous synthetic systems--the direct transformation of the stable, inert dinitrogen molecule (N2) into ammonia (NH3) relies on the powerful redox properties of metals. Here we show that nitrogen fixation can also be achieved by using a non-metallic buckminsterfullerene (C60) molecule, in the form of a water-soluble C60:gamma-cyclodextrin (1:2) complex, and light under nitrogen at atmospheric pressure. This metal-free system efficiently fixes nitrogen under mild conditions by making use of the redox properties of the fullerene derivative.     

B3N3H6与HF、 HCl和H2O形成的氢键和双氢键

运用量子化学从头算方法分别研究B₃N₃H₆与HF、 HCl和H₂O分子间形成的双氢键B—H…H—X与传统氢键N—H…X与X—H…X(X=F,Cl,O). 结果表明, 双氢键作用使B—H和H—X键长增大, 伸缩振动频率红移; 而传统氢键的作用使N—H和H—X键长增大, 频率红移. 电子密度拓扑性质分析表明, 这些相互作用具有氢键的基本特征. 自然键轨道分析表明, 超共轭和重杂化理论可以解释这些双氢键和氢键的形成机制.     

一个基于5-(2-吡啶基)-3,3′-联(1H-1,2,4-三氮唑)和均四苯甲酸的锌(II)超分子配合物的合成、晶体结构与荧光性质(英文)

在单核化合物[Zn(C9H7N7)(C10H4O8)(H2O)3]·3H2O中,Zn(II)金属中心离子分别和4个氧和2个氮原子配位,其中4个氧原子来自于一个去质子的均四苯甲酸(H2BTCA)和3个配位水分子,氮原子来自5-(2-吡啶基)-3,3'-联(1H-1,2,4-三氮唑)(H2pbt)配体.在这个结构中,相邻的单核单元之间通过分子内和分子间的O-H···O和NH···O氢键作用连接成二维超分子结构,且三唑环与苯环之间以及相邻吡啶环之间存在芳香堆积作用.此外,还研究了标题配合物的固态荧光性质.     

Molecular mechanism of anaerobic ammonium oxidation

Two distinct microbial processes, denitrification and anaerobic ammonium oxidation (anammox), are responsible for the release of fixed nitrogen as dinitrogen gas (N(2)) to the atmosphere. Denitrification has been studied for over 100 years and its intermediates and enzymes are well known. Even though anammox is a key biogeochemical process of equal importance, its molecular mechanism is unknown, but it was proposed to proceed through hydrazine (N(2)H(4)). Here we show that N(2)H(4) is produced from the anammox substrates ammonium and nitrite and that nitric oxide (NO) is the direct precursor of N(2)H(4). We resolved the genes and proteins central to anammox metabolism and purified the key enzymes that catalyse N(2)H(4) synthesis and its oxidation to N(2). These results present a new biochemical reaction forging an N-N bond and fill a lacuna in our understanding of the biochemical synthesis of the N(2) in the atmosphere. Furthermore, they reinforce the role of nitric oxide in the evolution of the nitrogen cycle.     

铜（Ⅱ）与芳酰腙及咪唑三元配合物的合成及晶体结构

合成了芳酰腙、咪唑和铜（路再生）的三元配合物[CuL（Himdz）]（H2L=2-羟基萘甲醛苯甲酰腙,Himdz=咪唑）,并通过单晶x射线衍射法确定了配合物结构．配合物的晶体结构分析表明,中心金属通过酰腙配体的酚基氧原子、亚胺基氮原子、去质子酰胺氧原子以及咪唑的氮原子形成平面四方形的N2O2配位环境．在晶胞中,配合物通过N-H…N分子间氢键作用形成一维链状结构．     

异佛尔酮类镉配合物的晶体结构及荧光性质

将(E)-2-(3-(4-(1H-三唑-1-基)苯乙烯基)-5,5-二甲基环己基-2-烯亚基)丙二腈(L)与Cd(OAc)2、CdI2自组装制备了配合物[CdL2(OAc)2]·2H2O(1)和CdL2I2(2)。运用X射线单晶衍射仪测定了配合物1和2的结构。配合物1为三斜晶系,中心Cd原子采取六配位模式,即与2个配体的氮原子、2个CH3COO-和2个H2O分子中的氧原子形成一个拉长的近似正八面体。而配合物2为单斜晶系,Cd原子采用四配位模式,与2个配体的氮原子和2个I-形成V型分子。这些分子通过分子间的氢键和π-π相互作用形成多维超分子结构。荧光和热重分析表明,1和2具有较强的荧光和较好的热稳定性。     

C6H5NH-H□X分子间氢键的理论研究

在B3LYP／6-311＋＋G（3df,2p）理论水平上,对C6H5NH-H□X（X=H2O,HCOH,CH3COCH3,NH3,CH2NH和HCN）氢键体系进行几何结构优化与振动频率计算,在所得稳定构型的基础上进行自然键轨道分析和热力学性质研究．结果表明,C6H5NH-H□X体系存在较弱的N—H□O与N—H□N氢键,氢键的形成使H—N伸缩振动频率明显红移．在298．15K和标准状态下,C6H5NH-H□X体系分子在气相的形成过程是一个放热、熵减的非自发过程．     

1,5-双(5-溴水杨醛)缩二氨基硫脲二丁基锡配合物的合成,晶体结构和杀菌活性研究

利用1,5-双(5-溴水杨醛)缩二氨基硫脲席夫碱与二丁基氧化锡为原料,在苯-甲苯混合溶剂中回流反应合成了一种新的有机锡席夫碱配合物,分子式为C23H18Br2N4O2SSn,用元素分析、红外光谱、核磁共振谱对目标化合物结构进行了表征,并用X-射线单晶衍射对其结构进行了确证.晶体结构解析表明,标题配合物的晶体属单斜晶系,P21/c空间群,每个独立单元中含有两个分子结构单元,晶胞参数:a=17.9191(9)(A),b=18.791(1)(A),c=17.9453(9)(A),a=115.447(1)埃琕=5456.2(5)(A)3,Z=4,Dcalc=1.709g/cm3.分子间经典的N-H…N氢键使分子相互结合形成了二聚体,后者再通过范德华作用力结合堆积形成完成的晶体结构.抑菌活性测定结果表明,标题化合物及其类似物的抑菌活性具有较大的选择性,对苏云金杆菌(B.thuringiensis)和枯草杆菌(B.Subtilis)的抑菌能力较高,而对大肠杆菌(E.Coli)和金黄色葡萄球菌(S.Aureus)的抑菌能力较低.     

Towards uranium catalysts

The forefront of research into the complexes of uranium reveals chemical transformations that challenge and expand our view of this unique element. Certain ligands form multiple bonds to uranium, and small, inert molecules such as nitrogen and carbon dioxide become reactive when in complex with the metal. Such complexes provide clues to the catalytic future of uranium, in which the applications of the element extend far beyond the nuclear industry. Most excitingly, the ability of uranium to use its outermost f electrons for binding ligands might enable the element to catalyse reactions that are impossible with conventional, transition-metal catalysts.     

镧和钕胞嘧啶配合物的量子化学研究

用量子化学ＩＮＤＯ方法研究了Ｌａ和Ｎｄ胞嘧啶配合物的电子结构和化学键，结果表明稀土对配位键的主要贡献来自其５ｄ轨道，６ｓ、６ｐ次之，４ｆ轨道几乎不参与成键，配位键为共价性。胞嘧啶的成键作用不只限于配位原子，而是扩展到配体整体，电子向稀土中心迁移是依靠共轭作用。     

取代基和配体的负离子效应对(TPFC)Mn(V)O轴向配位作用的影响

采用密度泛函理论(DFT)的BP86方法对系列位取代的锰(Ⅴ)-氧咔咯((TPFC)MnⅤO)配合物与咪唑的轴向配位作用，以及无位取代的(TPFC)MnⅤO与轴向配体4-甲基咪唑和吡咯的轴向配位性质进行理论研究。计算结果显示位取代基吸电子性质和轴向配体负离子效应均能缩短配位键长并增大结合能，显著增强(TPFC)MnⅤO配合物轴向配位作用。通过自然键轨道(NBO)分析发现影响其轴向配位作用的主要因素是轴向配体上氮原子的孤对电子轨道LP(N)与锰原子的孤对电子轨道LP(Mn,4s)和锰氧反键轨道*(MnO)间的二级微扰稳定化能E(2)，取代基吸电子效应和轴向配体负离子效应均能导致E(2)值增大，显著增强(TPFC)MnⅤO的轴向配位作用。     

Half-sandwich rhodium polychalcogenide complexes and a carbon insertion into Te-Te bond

Treatment of CptRh(PMe3)Cl2(1) (Cpt = 5(- tBu2C5H3) with [Et4N]2Se6 in DMF solution leads to the formation of cyclo-tetraselenido half-sandwich rhodium complexes CptRh(PMe3)(Se4) (2). The elimination of 2 with excess of nBu3P results in cyclo-diselenido rhodium complex CptRh(PMe3)(Se2) (3). 1 reacts with [nBu4N]2Te5 in DMF solution to yield cyclo-ditellurido rhodium complex CptRh (PMe3)(Te2) (4) in which carbon atom from CH2Cl2 can be inserted into Te-Te bond to form CptRh(PMe3)(TeCH2Te) (5). The new complexes 2-5 have been characterized by their IR, EI-MS, and 1H, 13C, 31P, 103Rh NMR spectra as well as elemental analysis.     

带羟乙基臂的单核钯(II)配合物的合成与晶体结构

以2-[二(2-氨基乙基)氨基]乙醇为配体,合成了带羟乙基臂的单核Pd(II)配合物:{PdI[(H2NCH2CH2)2NCH2CH2OH]}I。X-射线单晶衍射分析显示该配合物的晶体属于单斜晶系,P21/n空间群。配合物的分子由一个一价阳离子{PdI[(H2NCH2CH2)2NCH2CH2OH]}+和一个负一价的碘离子组成。Pd(II)离子与一个二乙烯三胺单元的三个氮原子以及一个碘原子配位。三个Pd-N键的键长在2.032(10)到2.068(4)之间。Pd(II)离子与三个氮原子及一个碘原子的配位环境构成一个扭曲的平面四边形构型,N1、N2、N3平面与N2、Pd1I、1平面之间的夹角为17.4(0.3)°。     

Unicellular cyanobacteria fix N2 in the subtropical North Pacific Ocean

Fixed nitrogen (N) often limits the growth of organisms in terrestrial and aquatic biomes, and N availability has been important in controlling the CO2 balance of modern and ancient oceans. The fixation of atmospheric dinitrogen gas (N2) to ammonia is catalysed by nitrogenase and provides a fixed N for N-limited environments. The filamentous cyanobacterium Trichodesmium has been assumed to be the predominant oceanic N2-fixing microorganism since the discovery of N2 fixation in Trichodesmium in 1961 (ref. 6). Attention has recently focused on oceanic N2 fixation because nitrogen availability is generally limiting in many oceans, and attempts to constrain the global atmosphere-ocean fluxes of CO2 are based on basin-scale N balances. Biogeochemical studies and models have suggested that total N2-fixation rates may be substantially greater than previously believed but cannot be reconciled with observed Trichodesmium abundances. It is curious that there are so few known N2-fixing microorganisms in oligotrophic oceans when it is clearly ecologically advantageous. Here we show that there are unicellular cyanobacteria in the open ocean that are expressing nitrogenase, and are abundant enough to potentially have a significant role in N dynamics.     

含噁唑啉环的苯并咪唑卡宾配体的设计合成及其在催化加成反应中的应用研究

以L-苯丙氨酸和苯并咪唑为原料,首次设计合成了一类具有新型结构的含噁唑啉环的苯并咪唑卡宾配体.首先将氨基酸还原和氨基酰化保护,然后将保护产物与苯并咪唑偶联,并构筑噁唑环,最后合成季铵盐等5步反应高效合成了6种具有中心手性的氮杂卡宾配体（NHC）6（A～F）.利用1 HNMR和13CNMR对相关产物进行了表征,同时利用二维核磁共振技术对重要的中间体5进行了结构表征,结果表明成功合成了目标配体,并确定化合物5为R-构型.研究了其对吲哚与C=O、C=N加成反应的催化性能,在C—C键的构筑中,将氮杂环卡宾配体6分别与Pd（Ⅱ）、Cu（Ⅱ）和Ag（Ⅰ）络合,得出最优反应条件为：6F为配体,二氯甲烷为溶剂、氧化银为碱、醋酸钯为金属,最高收率可达91%.在进一步的C—N键构筑的研究中,筛选出最优配体为6A,最高收率为89.4%.