首例含4, 4'-联吡啶和乙酸锌的光致变色化合物

采用一种新方法得到一维配位聚合物[Zn(CH₃COO)₂(4,4'-bipy)]_n(1)。配合物1的晶体结构和荧光性质已经有详细报道,但光致变色性质还没有相关的研究工作发表。通过研究化合物1在光照前后的紫外吸收光谱和顺磁共振谱,表明化合物1具有电子转移光致变色性能。实验结果验证了我们提出的利用非光致变色单元设计电子转移光致变色材料的新方法是有效可行的。     

由酰胺四酸配体构建的一个微孔三维金属有机骨架化合物及其高效可逆碘吸附性能

合成并表征了一个由酰胺键修饰并带有π-电子内壁的微孔三维金属有机骨架化合物[Cu₅(L)₂(H₂O)₅] (1) (H₄L=5,5'-((1H-pyrazole-3,5-dicarbonyl)bis(azanediyl))diisophthalic))。拓扑分析表明1为(3,3,4,4,6)-连接类型的网络结构,同时通过氮气和二氧化碳气体吸附验证了其孔道性质。同时1可以作为碘分子吸附的良好主体(1.94 mmol·g^-1,室温),并在碘分子的可逆吸附中具有出色的表现。     

4d-4f异金属配位聚合物的合成、结构和荧光性质

在水热反应条件下成功地合成了3个4d-4f异金属化合物{[LnAg₂(QA)₄(H₂O)₅](ClO₄)}_n(Ln=Nd(1),Tb(2),Eu(3);HQA=3-喹啉羧酸)。用单晶衍射分析,元素分析和粉末衍射分析对晶体结构进行了表征。化合物1~3同构,在bc平面形成二维层结构,抗衡离子ClO₄^-与二维层通过氢键作用形成三维超分子结构。研究了配合物2和3的荧光性质。     

由酰胺四酸配体构建的一个微孔三维金属有机骨架化合物及其高效可逆碘吸附性能

合成并表征了一个由酰胺键修饰并带有π-电子内壁的微孔三维金属有机骨架化合物[Cu₅(L)₂(H₂O)₅](1)(H₄L=5,5'-((1H-pyrazole-3,5-dicarbonyl)bis(azanediyl))diisophthalic))。拓扑分析表明1为(3,3,4,4,6)-连接类型的网络结构,同时通过氮气和二氧化碳气体吸附验证了其孔道性质。同时1可以作为碘分子吸附的良好主体(1.94mmol·g^-1,室温),并在碘分子的可逆吸附中具有出色的表现。     

含联苯三羧酸及二咪唑基吡啶配体的两个锌配位聚合物的合成、结构及荧光性质

以3,3’,5-联苯三羧酸(biphenyl-3,3’,5-tricarboxylicacid,H₃bpta)、2,6-二(1-咪唑基)吡啶(2,6-bis(imidazole-1-yl)pyridine,bip)、Zn(NO₃)₂·6H₂O和ZnCl₂为原料,在水热条件下合成了配位聚合物{[Zn₃(H₂O)₇(bpta)₂]·5H₂O}_n(1)和{[Zn₂Cl(bpta)(bip)₂]·2H₂O}_n(2)。并利用红外、元素分析和X-射线单晶衍射等对其结构进行表征。X-射线单晶衍射分析表明：化合物1属于单斜晶系,C2/c空间群,a=3.3171(11)nm,b=1.4957(5)nm,c=0.6951(2)nm,β=91.50°,Z=4;化合物2属于单斜晶系,P2/c 空间群,a=1.9604(4)nm,b=1.0357(2)nm,c=1.9987(4)nm,β=101.97(3)°,Z=4。化合物1通过bpta桥联Zn(Ⅱ)形成1D链,通过配位水与羧基氧之间的氢键作用构筑成3D结构。化合物2中bip桥联Zn(Ⅱ)构成1D螺旋链状结构,进一步通过bpta桥连形成2D网状结构。此外,对化合物1和2进行了热稳定性分析和荧光性质研究。     

一个晶态铅配位聚合物的合成、晶体结构、剥离及荧光性质

通过水热反应合成了1个二维层状结构的铅配位聚合物,[Pb(4-NPA)(H₂O)]_n(1)(4-H₂NPA=4-硝基邻苯二甲酸)。对化合物1进行了红外光谱、元素分析、热重性质以及单晶、粉末X射线衍射表征。在化合物1中,有机配体4-NPA₂-阴离子采用(κ¹-κ¹)(κ²-κ²)-μ₄桥连方式连接了4个Pb(Ⅱ)离子形成一维链状结构,该链状结构再通过1个羧酸基团形成一个二维无机层结构。利用"自上而下"的方法将该化合物在甲醇中进行了剥离实验。此外,我们还研究了化合物1的块状样品、剥离样品以及分散在甲醇中的样品的荧光性质。     

苯基多羧酸及含氮配体构筑的三维框架结构锌配位聚合物的合成、晶体结构和荧光性质

以醋酸锌、5-溴-1,2,4-苯基三羧酸(BTCAH₃)和4,4’-联吡啶(4,4’-bipy)为原料,在水热条件下合成了1个三维框架结构化合物[Zn₃(BTCA)₂(4,4’-bipy)₂](1),利用红外光谱、元素分析、热重、X-粉末衍射以及X-单晶衍射对该化合物进行了表征。化合物1是单斜晶系,C2/c空间群。在化合物1中,锌离子通过BTCA^3-配体的羧酸氧原子形成一个具有3-节点、4-连接的三维框架结构。4,4’-联吡啶配体在框架结构中连接锌离子。另外,研究了该化合物的热稳定性和固体荧光性质。     

单相Mn基白光金属有机骨架的合成及荧光性能

通过溶剂热法利用1,3,5-均苯三甲酸(H₃btc)与金属盐MnCl₂·4H₂O 反应,制备了一例新型白光金属有机骨架： (Me₄N)₃[Mn₃(btc)₂(Hbtc)(CH₃COO)]·7CH₃OH (1)。通过单晶X射线衍射和红外光谱对该化合物表征,并对其热稳定性及白色荧光性质进行研究。实验结果表明： 在紫外光激发下,化合物1具有发光现象并在287、355、375 nm的激发光波长下分别发射出红光、白光及蓝光。在390 nm(λ_ex=320 nm)处观察到配体H₃btc的强发射带,这是由配体中心的电子跃迁引起的,即π→π^*或π^*→n电子跃迁。化合物1在455和675 nm(λ_ex=355 nm)下显示双峰发射,与H₃btc相比显示红移,这可能是配体到金属电荷转移(LMCT)的结果。通过CIE色度坐标将化合物1的发射光谱可视化后发现白光色度坐标为(0.286,0.256)。     

基于半刚性四面体四齿配体构筑的Zn(Ⅱ)/Cd(Ⅱ)配位聚合物及其性质

在水热的条件下,利用四(4-吡啶氧甲基)甲烷(L₁)或四(3-吡啶氧甲基)甲烷(L₂)、1,4-萘二甲酸(1,4-NDC)和d¹⁰金属离子发生自组装反应合成了2个化合物{[Cd₂(L₁)(1,4-NDC)₂]·2H₂O}_n(1)和{[Zn₂(L₂)(1,4-NDC)₂]·DMF·3H₂O)}_n(2)。单晶结构表明化合物1是通过L₁配体与一维链[Cd(1,4-NDC)]_n相连构建而成的三维骨架化合物,而化合物2是一对螺旋链与另外的一维链相互垂直交联而形成二维网络结构。更为重要的是,通过引入2种不同空间位阻的配体,研究了辅助配体对金属有机配位聚合物结构多样性的影响。另外,它们的荧光性质也做了相应的探讨。     

两种N-2-嘧啶基-4-氨基苯磺酰Co(Ⅱ)配合物的合成、晶体结构及电催化性能研究

水热法合成两种新的Co(Ⅱ)化合物[Co(SD)₂(2,2’-bpy)](1)和{[Co(SD)₂(4,4’-bpy)]·4H₂O}_n(2)(SD=N-2-嘧啶基-4-氨基苯磺酰,2,2’-bpy=2,2’-联吡啶,4,4’-bpy=4,4’-联吡啶),并通过元素分析、红外光谱、X射线粉末衍射、热重分析、循环伏安法进行结构和性能表征。单晶X-ray衍射分析表明化合物1是三斜晶系,空间群为P1;化合物2是单斜晶系,空间群为C2/c。电催化实验发现化合物1和2对H₂O₂、HCHO都具有良好的电催化活性。     

三维多孔配位聚合物{[Zn2(mal)2(4,4'-bipy)(H2O)2]•2(H2O)0.25}∞ (mal＝丙二酸根)的合成、结构及性质研究

ZnO, 丙二酸及4,4'-bipy按物质的量之比1∶3∶0.3溶于H₂O和DMF混合溶剂中(体积比4∶1), 形成的无色溶液在50 ℃反应 3 d, 得到了标题化合物{[Zn₂(mal)₂(4,4'-bipy)(H₂O)₂]•2(H₂O)_0.25}_∞ (mal＝丙二酸根), 对其进行了元素分析、红外光谱和X射线衍射表征, 测定了晶体结构. 该聚合物属单斜晶系, P2₁/n空间群, a＝0.71215(16) nm, b＝1.8685(4) nm, c＝0.73890(17) nm, β＝91.486(5)°, V＝0.9829(4) nm³, Z＝4, D_c＝1.811 g/cm³, M_r＝268.03, F(000)＝542, μ＝25.02 cm^－1. 最终偏离因子R₁＝0.0499, wR₂＝0.1374. 该化合物中Zn原子和三个丙二酸根中的4个O原子、一个水分子和4,4'-bipy的一个N原子配位, 形成的ZnNO₅八面体通过4,4'-bipy和丙二酸根桥联, 组成一种新颖的三维多孔结构, 其孔道中充填游离水分子. 此外还研究了该聚合物的热性质.     

Synthesis and Thermal Decomposition of Mixed 2,4'-bipyridine-oxalato Complexes With Mn(II), Co(II), Ni(II) and Cu(II)

The mixed 2,4'-bipyridine-oxalato complexes of the formulae M(2,4'-bipy)₂ C₂ O₄ 2H₂ O (M (II)=Mn, Co, Ni, Cu; 2,4'-bipyridine=2,4'-bipy or L ; C₂ O^2– ₄ =ox) have been prepared and characterized. IR data show that the 2,4'-bipy coordinated with these metals(II) via the least hindered (4')N atom; that oxalate group acts as bidentate chelating ligand. Room temperature magnetic moments are normal for the orbital singlet states. The thermal decomposition of these complexes was investigated by TG, DTA and DTG in air. The endothermic or exothermic character of the decomposition of ML₂ (ox)2H₂ O was discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Synthesis and Thermal Studies of 2,4'-bipyridyl Complexes of Manganese(II) Salts

2,4'-Bipyridyl (2,4'-bipy or L) complexes of Mn(II) with the formulae MnL₂X₂·2H₂O (X_–=Cl, Br, NCS, NO₃), MnLSO₄·5H₂O and MnL₄(ClO₄)₂·2H₂O were synthesized and characterized via the IR spectra and magnetic, and conductivity measurements. The nature of the Mn(II)-ligand coordination is discussed. The thermal decompositions of these compounds were studied in air atmosphere. The mode of decomposition depends on the anion present, but the final product in all cases is Mn₃O₄. Some of the intermediates (MnL₂Cl₂, MnLCl₂, MnL₂Br₂, MnL₂(NCS)₂ and MnLSO₄) formed during the pyrolysis are isomeric with 2,2'-bipy and 4,4'-bipy complexes.This revised version was published online in November 2005 with corrections to the Cover Date.     

含新颖一维金属氧簇阳离子的聚金属氧簇化合物[{M(2,2'-bipy)}5O14]4- [2,2'-H2bipy]2(As2W18O62)2•8H2O (M＝Mo, W)的合成、晶体结构与表征

以Na₂WO₄•2H₂O, Na₂MoO₄•2H₂O, Na₂HAsO₄•7H₂O和2,2'-bipyridine为原料, 在水热条件下制得了含一维阳离子的聚金属氧簇化合物: [{M(2,2'-bipy)}₅O₁₄]₄[2,2'-H₂bipy]₂(As₂W₁₈O₆₂)₂•8H₂O (M＝Mo/W; 2,2'-bipy＝2,2'-bipyridyl), 并用元素分析, IR, TG和单晶X-ray衍射等手段进行了表征. 标题化合物属于单斜晶系, C2/c空间群, a＝4.1721(5) nm, b＝2.4629(5) nm, c＝1.7541(5) nm, β＝91.119(3)°, V＝18.021(5) nm³, Z＝2, R₁＝0.0629, wR₂＝0.1605 [I＞2σ(I)]. 标题化合物的阳离子链由五元金属氧簇构筑块[{M(2,2'-bipy)}₅O₁₄]^2＋通过氧原子桥联而成, 构筑块[{M(2,2'-bipy)}₅O₁₄]^2＋中的五个金属原子呈畸变的“A”字型排布, 阳离子展现出新颖的一维锯齿链状结构.     

Sensitivity and Resolution Development of Spiropyran‐based Molecular Photoswitches

The phenylazo moiety and its donor‐ and acceptor‐substituted derivatives are studied as effective auxochromes to improve their sensitivity and resolution for distinguishing between the spiro (SP; OFF) and mero (ON) forms in molecular photoswitching applications. Thus, 13 azospiropyran derivatives were synthesized and their spectroscopic and photokinetic behaviors were studied. The quality of photochromic reactions of the synthesized photochromic compounds were compared using a dose–response model. Interestingly, by replacing the nitro group in 6‐nitrospiropyran (ε = 0.42 × 10⁴ M^?1 cm^?1) with a simple phenylazo moiety, the SP form is still colorless and the color intensity of the merocyanine (MC) form is improved desirably by extending the conjugation length ( 1a , ε = 1.35 × 10⁴ M^?1 cm^?1). The presence of a hydrophilic OH group or a CH₃ group at the para position of phenylazo moiety revealed more or less the same photochromic properties as 1a . The OCH₃ group substituted at position 6 of the phenylazo moiety at the para position of the azobenzene moiety effectively increased the photochromic properties with the maximum k‐value for SP to MC switching. Meanwhile, Cl, Br, COOH, and NO₂ groups at the para position of the azobenzene moiety revealed the reduction in photochromic properties compared to 1a .     

An organic photochromic compound: (2S)‐2′‐ethoxy‐1,3,3‐trimethyl‐6′‐(piperidin‐1‐yl)spiro[indoline‐2,3′‐3′H‐naphtho[2,1‐b][1,4]oxazine]

In the course of our synthesis of hybrid photochromic compounds, the unexpected new organic photochromic title compound, C₂₉H₃₃N₃O₂, (I), was obtained. It is a derivative of the parent spirooxazine 1,3,3‐trimethyl‐6′‐(piperidin‐1‐yl)spiro[indoline‐2,3′‐3′H‐naphtho[2,1‐b][1,4]oxazine], (II). The 2′‐ethoxy group gives (I) different photochromic properties from its parent spirooxazine (II).     

Thermal Studies on Some Lanthanide Complexes

The new mixed ligand complexes with the formulae Zn(2-bipy)(ox), Zn(4-bipy)_1.5 (ox)H₂ O, Zn(2,4'-bipy)₂ (ox)2H₂ O, Cd(2-bipy)(ox)2H₂ O, Cd(4-bipy)₂ (ox) and Cd(2,4'-bipy)(ox)2H₂ O (2-bipy, 4-bipy, 2,4'-bipy=2,2'-, 4,4'- and 2,4'bipyridine, ox=oxalate) were prepared. The thermal decompositions of these compounds were studied by means of TG, DTG and DTA in air. During heating the complexes decompose via different intermediate products to ZnO and CdO. The Zn(II) complexes are thermally more stable than the corresponding Cd(II) complexes. The influence of nitrogen atom position in the bipyridine isomers and nature of central atom on the thermal behaviour of these complexes was discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

A fourfold interpenetrating cadmium(II) metal–organic framework based on 2,4,6‐tris(pyridin‐4‐yl)‐1,3,5‐triazine with reversible photochromic properties

2,4,6‐Tris(pyridin‐4‐yl)‐1,3,5‐triazine (tpt), as an organic molecule with an electron‐deficient nature, has attracted considerable interest because of its photoinduced electron transfer from neutral organic molecules to form stable anionic radicals. This makes it an excellent candidate as an organic linker in the construction of photochromic complexes. Such a photochromic three‐dimensional (3D) metal–organic framework (MOF) has been prepared using this ligand. Crystallization of tpt with Cd(NO₃)₂·4H₂O in an N,N‐dimethylacetamide–methanol mixed‐solvent system under solvothermal conditions afforded the 3D MOF poly[[bis(nitrato‐κ²O,O′)cadmium(II)]‐μ₃‐2,4,6‐tris(pyridin‐4‐yl)‐1,3,5‐triazine‐κ³N²:N⁴:N⁶], [Cd(NO₃)₂(C₁₈H₁₂N₆)]_n, which was characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis and single‐crystal X‐ray diffraction. The X‐ray diffraction crystal structure analysis reveals that the asymmetric unit contains one independent Cd^II cation, one tpt ligand and two coordinated NO₃^? anions. The Cd^II cations are connected by tpt ligands to generate a 3D framework. The single framework leaves voids that are filled by mutual interpenetration of three independent equivalent frameworks in a fourfold interpenetrating architecture. The compound shows a good thermal stability and exhibits a reversible photochromic behaviour, which may originate from the photoinduced electron‐transfer generation of radicals in the tpt ligand.     

Photochromic liquid crystalline structures containing azobenzene moieties

Novel liquid crystalline photochromic materials of the type 4-R-C₆H₄-N=N-C₆H₄-O(CH₂)_n-N(CH₂CH₂OH)₂, where R is NO₂, H, CN, O-n-C₈H₁₇, phenyl, 4-O₂NC₆H₄, were prepared. Some of them are photoconductive. These materials were used for the preparation of light-sensitive polymers in which the photoactive moieties were attached to polyurethane chain. Photochromism of these compounds is based on trans-cis isomerization of azobenzene group. An example of the photochromic activity is presented on solid solution of one material (R = O-n-C₈H₁₇, n = 5) in poly(methyl methacrylate) matrix.