颜色可区分的氰桥五边形带经亲铜作用聚集的异金属多形体

水热条件下,环境友好的K₂[Ni(CN)₄]能缓慢水解形成cis-[Ni(CN)₂(H₂O)₄]单元和氰基配体,并进一步与金属铜(Ⅰ)原子组装形成异金属的五边形带。这些五边形带通过亲铜聚集作用形成二维有色的超分子多形体[(CuCN)₂Ni(CN)₂(H₂O)₄](1和2)。研究发现,低温条件下形成了密集态的深蓝色的化合物1,然而高温反应条件形成疏松态的紫色化合物2,这一现象与高温高压的反应条件形成密集态的物质这一规律相违背。结构的进一步分析发现五边形环尺寸的微小改变和二维超分子层间距离的差异是引起这一反常的原因。除此之外,这两个新的化合物也是少见的由亲铜性聚集作用诱导的着色异常的多形体的例子,显示了从深蓝色到紫色的颜色改变。磁性研究证实了平面正方形的[Ni(CN)₄]^2-中的金属镍(Ⅱ)转换成了有着基态自旋S=1的八面体配位几何中心。     

含大环[Ni([15]aneN5]2+氰基桥联四核簇合物的合成、结构和磁性质

用1,4,7,10,13-五氮十五烷(cpad)作为端基配体,合成了2个同构化合物[{Ni(cpad)}₃M(CN)₆]₂[M(CN)₆](ClO₄)₃·6H₂O (M=Cr³⁺,1;Fe³⁺,2),其中[M(CN)₆]^3-通过氰基桥联配位,4个[Ni(cpad)]²⁺阳离子形成四核簇[{Ni(cpad)}₃M(CN)₆]³⁺,游离的[M(CN)₆]^3-和ClO₄^-为平衡阴离子。晶体参数如下：1,三方晶系,P3c1空间群,a=1.5144 1(18) nm,c=3.080 7(6) nm,V=6.118 9(15) nm³,Z=2;2,三方晶系,P3c1空间群,a=1.4976 2(17) nm,c=3.087 8(5) nm,V=5.997 6(14) nm³,Z=2。变温磁化率显示在四核簇内氰基桥联的金属离子之间存在铁磁相互作用。     

氰基桥联的Fe2Ni双之字链的合成与磁性

利用四氰基构筑单元和不同位阻的吡啶类配体,合成了3例氰基桥联的Fe₂^ⅢNi^Ⅱ链状化合物。化合物{[Fe（bpy）（CN）₄]₂[Ni（bp）₂]·2H₂O}_n（1）（bpy=2,2''-联吡啶;bp=4-苯基吡啶）,{[Fe（bpy）（CN）₄]₂[Ni（papy）₂]·H₂O}_n（2）（papy=4-（苯基氮烯）吡啶）和{[Fe（bpy）（CN）₄]₂[Ni（azp）]·4H₂O}_n（3）（azp=1,2-二（吡啶-4-基）二氮烯）均为双之字型的链状结构。磁性测试表明化合物1~3均表现为链内的铁磁相互作用。化合物1表现出单链磁体行为,有效能垒为10.9 K。     

咪唑-芳香多羧酸金属有机骨架化合物的合成、结构及性质

以5-(1H-咪唑)异酞酸(H₂L)为配体,在水热条件下合成了3个金属有机框架化合物:[PrL(HL)(H₂O)₂]·H₂O(1),Er(H_0.5L)₂(2)和[CoL(H₂O)₂]·H₂O(3)。单晶X-射线衍射测试结果表明,3个化合物都属于单斜晶系,P2₁/c空间群。化合物1中,Pr³⁺为九配位,而化合物2和3中,Er³⁺和Co²⁺均为六配位。在镧系配合物1和2中,配体中氮原子未参与配位。1为2D折叠形结构,2为3D框架结构。在过渡金属配合物3中,氮原子与Co²⁺配位,这有助于形成平面二维结构。化合物1和3通过分子间π-π堆积,进一步形成3D结构。3个化合物均展现出较好的热稳定性。     

含樟脑衍生物氰基桥联双金属配合物的合成、结构及磁性质

采用樟脑衍生物为配体，分别合成了氰基桥联Cu(Ⅱ)-Fe(Ⅲ)-Cu(Ⅱ)三核配合物[{Cu(D,L-La)₂}₂Fe(CN)₆](ClO₄) (1)和Mn(Ⅲ)-Fe(Ⅲ)双核配合物[Mn(D,L-Lb)(DMF)(Tp)Fe(CN)₃]·(H₂O)₆ (2)。晶体结构分析表明，化合物1中Cu(Ⅱ)离子处于五配位的配位环境，分别和1个D-La，1个L-La及[Fe(CN)₆]^3-中的1个氰基配位，2个Cu(Ⅱ)离子通过[Fe(CN)₆]^3-桥联。通过分子间氢键作用，化合物1形成二维超分子网络结构。化合物2中，[(Tp)Fe(CN)₃]^-通过其中的1个氰基与[Mn(D，L-Lb)]⁺桥联，其中Mn(Ⅲ)离子为六配位，分别和四齿配体Lb的2个氧原子和2个氮原子、DMF的1个氧原子及[(Tp)Fe(CN)₃]^-中的氰基氮原子配位。磁性研究表明，在化合物1中，Cu(Ⅱ)离子与Fe(Ⅲ)离子之间表现出铁磁相互作用，用哈密顿函数H=-2J(S₁·S₂+S₂·S₃)对其χ_MT-T曲线进行拟合，得到1的朗日因子g为2.190，交换常数J为0.55 cm^-1。     

有机杂化硫代碲酸盐化合物（H2en）TeS3和[Ni（en）3]TeS3的溶剂热合成与表征

用低温溶剂热法合成了2种分立结构的有机杂化硫代碲（Ⅳ）酸盐化合物（H₂en）TeS₃（1）和[Ni（en）₃]TeS₃（2）（en=乙二胺）,通过X-射线单晶衍射,红外光谱,元素分析等手段对它们的结构进行了表征。晶体结构解析结果表明：2个化合物均属单斜晶系,空间群分别为P2₁和P2₁/c。化合物1和2具有孤立三角锥[TeS₃]^2-阴离子,化合物1的平衡阳离子为双质子化乙二胺[H₂en]²⁺,阴离子基团[TeS₃]^2-和阳离子基团[H₂en]²⁺之间通过N-H…S氢键连接。化合物2的阳离子基团为过渡金属Ni与乙二胺的配合物[Ni（en）₃]²⁺。另外,对该2种晶体进行了紫外-可见漫反射光谱测试和热重分析。     

两例具有大磁滞的氰根桥联{Fe2ⅢNiⅡ}单链磁体

我们利用具有不同对称性的同分异构体,通过改变分子间氢键网络,操控单链磁体行为,成功合成了2 例化合物：[Ni^Ⅱ(L1)][Fe^Ⅲ(Tp)(CN)₃]₂·3.5H₂O (1)和[Ni^Ⅱ(L2)][Fe^Ⅲ(Tp)(CN)₃]₂·3H₂O (2),其中Tp=hydrotris(pyrazolyl)borate,L1=3,4-bis(1H-imid-azol-1-yl)thiophen,L2=1,2-bis(1H-imidazol-1-yl)thiophen)。磁性研究表明,1和2表现为具有不同矫顽场的单链磁体行为。1的矫顽场为8.41 kOe,而2的矫顽场为3.84 kOe。     

基于[(Tp)Fe(CN)3]-氰基桥联双核配合物的合成、结构和磁性研究

采用[TpFe^Ⅲ(CN)₃]^-作为构筑基块，合成并表征了一个氰基桥联双核配合物[(Tp)Fe^Ⅲ(CN)₃Cu^Ⅱ(bpy)₂]ClO₄·CH₃OH (1)。对化合物1进行了晶体结构分析，其晶胞参数为a=0.904 26(5) nm，b=1.352 56(7) nm，c=1.556 02(8) nm，α=106.08(1)°，β=95.79(1)°，γ=91.01(1)°，P1空间群。在这个化合物中，[TpFe^Ⅲ(CN)₃]通过其中1个氰基与[Cu(bpy)₂]²⁺桥联，而另外2个氰基未参与配位。磁性研究表明，在化合物1中，Cu(Ⅱ)与Fe(Ⅲ)离子之间表现为铁磁相互作用。用哈密顿函数H=-2JS_FeS_Cu对其χ_MT-T曲线进行了拟合，得到1的朗德因子g=2.34和交换常数J=5.52 cm^-1。     

以T型三羧酸配体构筑的具有2D→3D穿插结构的金属有机框架的合成、结构及性质

采用溶剂热合成法,利用T型三羧酸配体3,4',5-联苯三羧酸(H₃BPT=biphenyl-3,4',5-tricarboxylic acid)制备并表征了2个2D→3D穿插结构的金属有机框架结构,{[Ni₃(BPT)₂(bpe)₂(H₂O)₆]·2DMF·7H₂O}n (1)和{[Ni₃(BPT)₂(bpea)₂(H₂O)₆]·2DMF·5H₂O}n (2)(bpe=1,2-bis(4-pyridyl)ethylene,bpea=1,2-bis(4-pyridyl)ethane,DMF=N,N-dimethylformamide).在这2个化合物中,BPT配体和含氮配体bpe或bpea共同连接相邻的Ni(Ⅱ)中心,形成(3,4)-连接的(6³)(6⁵.8)二维双层结构.相邻双层结构间相互穿插,形成具有聚轮烷结构的2D→3D互锁结构.气体吸附性质表明,化合物1对CO₂和N₂具有一定的吸附能力.     

含硅铁键环状化合物[Me2Si-η5-C5H4Fe(CO)(PPh3)][Me2Si-η5-C5H4Fe- (CO)2－n(PPh3)n] (n＝0或1)的合成与结构

鉴于含硅-过渡金属键化合物作为催化剂具有重要的应用价值, 在我们最近发现的化合物(η⁵,η⁵-C₅H₄Me₂SiSi-Me₂C₅H₄)Fe₂(CO)₄ (1)的硅硅键和铁铁键复分解重排反应可以有效地合成含有两个硅铁键的环状化合物[Me₂Si-η⁵-C₅H₄- Fe(CO)₂]₂ (2)的基础上, 对该硅铁键环状化合物的三苯基膦取代衍生物[Me₂Si-η⁵-C₅H₄-Fe(CO)(PPh₃)][Me₂Si-η⁵-C₅H₄Fe(CO)_2－n(PPh₃)_n] (3: n＝0, 5: n＝1)的合成方法进行了研究. 发现化合物1在三苯基膦存在下的复分解重排反应是合成单三苯基膦取代产物3的最好方法; 而双三苯基膦取代化合物5则可通过光照条件下2与三苯基膦发生羰基取代反应而得到, 产物中含有的顺反异构体可利用制备薄层色谱法分离. 利用X射线衍射法测定了化合物3的分子结构, 考察了三苯基膦配体的存在对分子结构的影响以及三苯基膦与铁形成的配位键的稳定性.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.