新型手性双核Salen配合物的合成与表征

采用新型Salen中间体I(由3，5-二叔丁基水杨醛、2，6-二酰基-4-甲基苯酚、(R，R)环己二胺为原料合成)合成了4个新型手性双核Salen配合物[Zn₂L·3H₂O (2)、Cu₂L·H₂O (3)、CO₂L (4)、Ni₂L (5)]，(L是由中间体I和邻苯二胺合成的手性二聚Salen配体)。用¹H NMR、FTIR、UV-Vis、CD光谱对配体和配合物进行了表征，详细讨论了红外光谱、电子吸收光谱、圆二色光谱的性质。采用激子耦合理论解释了此类手性化合物圆二色谱的Cotton效应和Cotton裂分，Cotton裂分的方向依赖于环己二胺的构象，(R，R)环己二胺决定了Salen化合物的手征性为负。     

手性自旋转换铁(Ⅱ)席夫碱配合物的合成、结构及其磁性研究

通过高氯酸亚铁,4-(咪唑-2-甲醛)丁腈和光学纯苯乙胺衍生物的自组装成功合成了2个纯手性单核自旋转换铁(Ⅱ)化合物fac-Λ-[Fe(R-L1)₃](ClO₄)₂(1),fac-Λ-[Fe(R-L₂)₃](ClO₄)₂(2).利用X-射线单晶衍射、元素分析(EA)、红外光谱(IR)、核磁共振氢谱(¹H NMR)、紫外光谱(UV)、圆二光谱(CD)等手段对配合物结构进行了表征.X-射线单晶衍射表明在化合物1和2中,铁(Ⅱ)金属中心与3个不对称双齿手性席夫碱配体中的6个氮原子配位形成八面体配位环境.每个结构基元中包含1个[Fe(L)₃]²⁺阳离子和2个高氯酸根阴离子.由于铁(Ⅱ)中心周围手性配体的螺旋协调配位使[Fe(L)₃]²⁺形成单一手性Λ构型.Fe(Ⅱ)N键长表明配合物1和2中的铁(Ⅱ)在低自旋状态.在[Fe(L)₃]²⁺中,相邻配体中的苯环和咪唑环形成分子内π-π相互作用.配合物1和2通过分子间C-H…π相互作用形成三维超分子结构.CD光谱证实配合物1和2在溶液中的光学活性.磁性测试表明配合物1和2分别在232和250 K发生自旋转换.由于配合物1和2具有相同的手性空间群和类似的堆积方式和分子间相互作用,导致1和2表现出不同自旋转换温度的原因主要是取代基效应.     

基于N-乙酰-L-酪氨酸构筑的两例纯手性钴(Ⅱ)配合物的合成、结构及性质

利用手性配体N-乙酰-L-酪氨酸(Hacty)与钴盐通过溶液法合成了2例纯手性配合物{[Co(acty)(bpp)₂(H₂O)₂](NO₃)·2H₂O}_n(1)和{[Co₂(acty)₂(bpe)₃(H₂O)₃](ClO₄)₂·4H₂O}_n(2)(bpp=1,3-联(4-吡啶)丙烷,bpe=1,2-联(4-吡啶)乙烷),并对它们进行了元素分析(EA)、红外光谱(IR)、紫外光谱(UV)、热重(TG)、粉末X射线衍射(PXRD)及X射线单晶衍射测定。配合物1属于单斜晶系P2₁空间群,六配位的Co(Ⅱ)离子被bpp配体连接形成一维右手螺旋链结构。配合物2属于三斜晶系P1空间群,六配位的双核Co(Ⅱ)离子被bpe配体连接形成一维带状链结构。在氢键的作用下,它们均形成三维超分子结构,深入讨论了不同构型的含N辅助配体对配合物结构的影响。此外,测定了2例手性配合物的圆二色(CD)光谱。     

由V-型双咪唑和芳香羧酸根配体共同构筑的Zn(Ⅱ)配位聚合物的合成,结构与性能

在溶剂热条件下,将一个V-型双咪唑配体1,1'-(5-甲基-1,3-亚苯基)二(1H-咪唑)(Bim)与其它V-型辅助配体(具有不同的对称性和功能基团的芳香羧酸)一起与金属盐ZnSO₄·6H₂O进行反应,分别得到2个新的配位聚合物{[Zn(Bim)(Bra)₂]·CH₃OH}_n(1)和{[Zn(Bim)(Mpa)]·H₂O}_n(2)(Bra^-=5-溴烟酸根,Mpa^2-=5-甲基间苯二甲酸根)。采用红外光谱、元素分析、X射线粉末衍射、X射线单晶衍射和热重分析对配合物进行了表征。配合物1是由配体Bim桥联形成的一维链状结构并进一步通过链间的π…π、C-H…π和Br…π作用堆积成一个三维超分子。在2中,Zn(Ⅱ)离子通过Mpa^2-桥联形成左手和右手螺旋链,这些具有不同手性的螺旋链进一步通过Bim联接形成具有(4,4)拓扑结构的内消旋的二维层。相邻的二维层之间的交错对插、层间配体分子Bim的咪唑环和苯环的双重π…π作用最终形成了三维超分子。固态荧光测试结果表明:在室温条件下,配体Bim和配合物1~2均出现了有趣的多重发射峰,而且在配合物1中四配位的Zn(Ⅱ)离子中心能显著地敏化配体Bim的高强度发射峰。     

由V-型双咪唑和芳香羧酸根配体共同构筑的Zn(Ⅱ)配位聚合物的合成,结构与性能

在溶剂热条件下,将一个V-型双咪唑配体1,1'-(5-甲基-1,3-亚苯基)二(1H-咪唑)(Bim)与其它V-型辅助配体(具有不同的对称性和功能基团的芳香羧酸)一起与金属盐ZnSO₄·6H₂O进行反应,分别得到2个新的配位聚合物{[Zn(Bim)(Bra)₂]·CH₃OH}_n(1)和{[Zn(Bim)(Mpa)]·H₂O}_n(2)(Bra^-=5-溴烟酸根,Mpa^2-=5-甲基间苯二甲酸根)。采用红外光谱、元素分析、X射线粉末衍射、X射线单晶衍射和热重分析对配合物进行了表征。配合物1是由配体Bim桥联形成的一维链状结构并进一步通过链间的π…π、C-H…π和Br…π作用堆积成一个三维超分子。在2中,Zn(Ⅱ)离子通过Mpa^2-桥联形成左手和右手螺旋链,这些具有不同手性的螺旋链进一步通过Bim联接形成具有(4,4)拓扑结构的内消旋的二维层。相邻的二维层之间的交错对插、层间配体分子Bim的咪唑环和苯环的双重π…π作用最终形成了三维超分子。固态荧光测试结果表明:在室温条件下,配体Bim和配合物1~2均出现了有趣的多重发射峰,而且在配合物1中四配位的Zn(Ⅱ)离子中心能显著地敏化配体Bim的高强度发射峰。     

基于双齿咪唑席夫碱配体的两个手性自旋转换铁(Ⅱ)配合物

以含有苯环和咪唑环的手性双齿席夫碱为配体, 合成了2个纯手性单核自旋转换铁(Ⅱ)配合物fac-Δ -[Fe(S-L₁)₃][ClO₄]₂ (1), mer-Λ -[Fe(R-L₂)₃][ClO₄]2· Et₂O (2)(L₁=1-对氯苯基-N-(1-正丙烯基-¹H-咪唑-2-亚甲基)乙胺; L₂=1-苯基-N-(1-异丙烯基-1H-咪唑-2-亚甲基)乙胺)。利用X-射线单晶衍射、元素分析(EA)、红外光谱(IR)、核磁共振氢谱(¹H NMR)、紫外光谱(UV)、圆二光谱(CD)等手段对配合物结构进行了表征。X-射线单晶衍射表明在配合物1和2中, 铁(Ⅱ)金属中心与3个不对称双齿手性席夫碱配体中的6个氮原子配位形成八面体配位环境。配合物1中每个结构基元中包含1个[Fe(L_n)₃]²⁺阳离子和2个高氯酸根阴离子。而配合物2中每个结构基元中包含2个[Fe(L_n)₃]²⁺阳离子、4个高氯酸根阴离子和1个乙醚分子。由于铁(Ⅱ)中心周围手性配体的螺旋协调配位使[Fe(L_n)₃]²⁺形成单一构型。Fe(Ⅱ)-N键长表明配合物1中的铁(Ⅱ)在低自旋状态, 而配合物2中的铁(Ⅱ)在高自旋状态。在[Fe(L_n)₃]²⁺中, 相邻配体中的苯环和咪唑环形成分子内π-π相互作用。配合物1和2通过分子间C-H…π和C-Cl…π相互作用形成超分子结构。CD光谱证实配合物1和2在溶液中的光学活性。磁性测试表明配合物1和2分别在372 K和146 K发生自旋转换。由于配合物1和2具有不同的堆积方式和分子间相互作用, 导致1和2表现出不同的自旋转换温度。     

基于N-乙酰-L-酪氨酸构筑的两例纯手性钴(Ⅱ)配合物的合成、结构及性质

利用手性配体N-乙酰-L-酪氨酸(Hacty)与钴盐通过溶液法合成了2例纯手性配合物{[Co(acty)(bpp)₂(H₂O)₂](NO₃)·2H₂O}_n (1)和{[Co₂(acty)₂(bpe)₃(H₂O)₃](ClO₄)2·4H₂O}_n (2)(bpp=1,3-联(4-吡啶)丙烷,bpe=1,2-联(4-吡啶)乙烷),并对它们进行了元素分析(EA)、红外光谱(IR)、紫外光谱(UV)、热重(TG)、粉末X射线衍射(PXRD)及X射线单晶衍射测定。配合物1属于单斜晶系P2₁空间群,六配位的Co(Ⅱ)离子被bpp配体连接形成一维右手螺旋链结构。配合物2属于三斜晶系P1空间群,六配位的双核Co(Ⅱ)离子被bpe配体连接形成一维带状链结构。在氢键的作用下,它们均形成三维超分子结构,深入讨论了不同构型的含N辅助配体对配合物结构的影响。此外,测定了2例手性配合物的圆二色(CD)光谱。     

基于双齿咪唑席夫碱配体的两个手性自旋转换铁(Ⅱ)配合物

以含有苯环和咪唑环的手性双齿席夫碱为配体, 合成了2个纯手性单核自旋转换铁(Ⅱ)配合物fac-Δ-[Fe(S-L₁)₃][ClO₄]₂ (1), mer-Λ-[Fe(R-L₂)₃][ClO₄]₂·Et₂O (2)(L₁=1-对氯苯基-N-(1-正丙烯基-1H-咪唑-2-亚甲基)乙胺;L₂=1-苯基-N-(1-异丙烯基-1H-咪唑-2-亚甲基)乙胺)。利用X-射线单晶衍射、元素分析(EA)、红外光谱(IR)、核磁共振氢谱(¹H NMR)、紫外光谱(UV)、圆二光谱(CD)等手段对配合物结构进行了表征。X-射线单晶衍射表明在配合物1和2中, 铁(Ⅱ)金属中心与3个不对称双齿手性席夫碱配体中的6个氮原子配位形成八面体配位环境。配合物1中每个结构基元中包含1个[Fe(L_n)₃]²⁺阳离子和2个高氯酸根阴离子。而配合物2中每个结构基元中包含2个[Fe(L_n)₃]²⁺阳离子、4个高氯酸根阴离子和1个乙醚分子。由于铁(Ⅱ)中心周围手性配体的螺旋协调配位使[Fe(L_n)₃]²⁺形成单一构型。Fe(Ⅱ)-N键长表明配合物1中的铁(Ⅱ)在低自旋状态, 而配合物2中的铁(Ⅱ)在高自旋状态。在[Fe(L_n)₃]²⁺中, 相邻配体中的苯环和咪唑环形成分子内π-π相互作用。配合物1和2通过分子间C-H…π和C-Cl…π相互作用形成超分子结构。CD光谱证实配合物1和2在溶液中的光学活性。磁性测试表明配合物1和2分别在372 K和146 K发生自旋转换。由于配合物1和2具有不同的堆积方式和分子间相互作用, 导致1和2表现出不同的自旋转换温度。     

基于5-(4-(2,6-二(2-吡嗪基)-4-吡啶基)苯氧基)间苯二甲酸的Mn(Ⅱ)和Ca(Ⅱ)配位聚合物的合成与晶体结构

采用对苯二甲酸为模板剂, 溶剂热法合成了2个以5-(4-(2, 6-二(2-吡嗪基)-4-吡啶基)苯氧基)间苯二甲酸(H₂L)为配体的金属-有机配位聚合物:{[MnL] ·0.5H₂O}_n (1), {[CaL(H₂O)₂]·H₂O}_n (2)。通过X-射线单晶衍射, 元素分析和红外光谱进行了结构表征。结构分析表明, 1具有(3, 3)-连接的不同手性型二维层面结构, 这些交替出现的单手性左旋型和右旋型二维平面通过配体的吡啶环与吡嗪环间π…π堆积作用构成了三维超分子结构;2是通过L^2-配体羧基桥连接相邻的Ca(Ⅱ)金属中心, 形成一条平行于b轴方向的一维链结构。研究了配位聚合物的热稳定性和2的荧光性质。     

基于半胱氨酸衍生物的两个手性多核金属簇合物的结构和磁性质

采用具有手性的半胱氨酸衍生物配体L-硫代脯氨酸(LTP)分别和高氯酸钴、高氯酸锰反应得到配合物[Co(LTP)₂]_n(1)和[Mn(LTP)₂]_n(2)。用X-射线衍射对这2个化合物的晶体结构进行了测定,结果表明4个LTP配体采用μ₂-N₁O₂:O₃的配位模式将八面体配位构型的金属离子连接起来构成二维结构。磁性测定表明2个化合物中金属离子之间有弱的反铁磁相互耦合作用。     

The versatile, efficient, and stereoselective self-assembly of transition-metal helicates by using hydrogen-bonds

A diverse range of dinuclear double-stranded helicates in which the ligand strand is built up by using hydrogen-bonding has been synthesized. The helicates, formulated as [Co(2)(L)(2)(L-H)(2)X(2)], readily self-assemble from a mixture of a suitable pyridine-alcohol compound (L; for example, 6-methylpyridine-2-methanol, 1), and a CoX(2) salt in the presence of base. Nine such helicates have been characterized by X-ray crystallography. For helicates derived from the same pyridine-alcohol precursor, a remarkable regularity was found for both the molecular structure and the crystal packing arrangements, regardless of the nature of the ancillary ligand (X). A notable exception was observed in the solid-state structure of [Co(2)(1)(2)(1-H)(2)(NCS)(2)] for which intermolecular nonbonded contacts between the sulfur atoms (SS=3.21 A) lead to the formation of 1D chains. Helicates derived from (R)-6-methylpyridine-2-methanol (2) are soluble in solvents such as CH(3)CN and CH(2)Cl(2), and their self-assembly could be monitored in solution by (1)H NMR, UV/Vis, and CD titrations. No intermediate complexes were observed to form in a significant concentration at any point throughout these titrations. The global thermodynamic stability constant of [Co(2)(2)(2)(2-H)(2)(NO(3))(2)] was calculated from spectrophotometric data to be logbeta=8.9(8). The stereoisomerism of these helicates was studied in some detail and the self-assembly process was found to be highly stereoselective. The chirality of the ligand precursors can control the absolute configuration of the metal centers and thus the overall helicity of the dinuclear assemblies. Furthermore, the enantiomers of rac-6-methylpyridine-2-methanol (3) undergo a self-recognition process to form exclusively homochiral helicates in which the four pyridine-alcohol units possess the same chirality.     

Supramolecular coordination chemistry in aqueous solution: lanthanide ion-induced triple helix formation

The self-assembly of dinuclear triple helical lanthanide ion complexes (helicates), in aqueous solution, is investigated utilizing laser-induced, lanthanide luminescence spectroscopy. A series of dinuclear lanthanide (III) helicates (Ln(III)) based on 2,6-pyridinedicarboxylic acid (dipicolinic acid, dpa) coordinating units was synthesized by linking two dpa moieties using the organic diamines (1R,2R)-diaminocyclohexane (chxn-R,R) and 4,4'-diaminodiphenylmethane (dpm). Luminescence excitation spectroscopy of the Eu3+ 7F0-->5D0 transition shows the apparent cooperative formation of neutral triple helical complexes in aqueous solution, with a [Eu2L3] stoichiometry. Eu3+ excitation peak wavelengths and excited-state lifetimes correspond to those of the [Eu(dpa)3]3- model complex. CD studies of the Nd(III) helicate Nd2(dpa-chxn-R,R)3 reveal optical activity of the f-f transitions, indicating that the chiral linking group induces a stable chirality at the metal ion center. Molecular mechanics calculations using CHARMm suggest that the delta delta configuration at the Nd3+ ion centers is induced by the chxn-R,R linker. Stability constants were determined for both ligands with Eu3+, yielding identical results: log K = 31.6 +/- 0.2 (K in units of M-4). Metal-metal distances calculated from Eu3+-->Nd3+ energy-transfer experiments show that the complexes have metal-metal distances close to those calculated by molecular modeling. The fine structure in the Tb3+ emission bands is consistent with the approximate D3 symmetry as anticipated for helicates.     

CD spectra of polynuclear complexes of diimine ligands: theoretical and experimental evidence for the importance of internuclear exciton coupling

We have recently reported on dinuclear complexes Lambda,Lambda-[Co(2)L(2)Cl(2)]CoCl(4) of two novel chiral ligands (1a and 1b) which contain pyridyl-imine chelate groups (Telfer, S. G.; Sato, T.; Kuroda, R. Chem. Commun. 2003, 1064-1065). The absolute configuration of the cobalt(II) centers was unambiguously assigned by X-ray crystallography. However, the sign of the exciton couplets in their CD spectra was opposite to that expected on the basis of the stereochemistry of the metal centers. We present a rationalization of these anomalous spectra in terms of an "internuclear" exciton coupling model which takes into account the coupling of chromophores located on different metal centers. We have performed a series of semiempirical (ZINDO) calculations which provide quantitative support to this model. These findings show that the absolute configuration of the metal centers in a polynuclear complex may be incorrectly assigned on the basis of CD data if internuclear coupling effects are not taken into consideration. We summarize the CD spectral data of number of other chiral polynuclear complexes from the literature, including dinuclear complexes bridged by the 2,2'-bipyrimidine ligand, complexes of the HAT ligand, and dinuclear triple-stranded helicates. The amplitude of the CD spectra of many of these complexes is not additive with the number of chromophores. These anomalous spectra can be accounted for by taking internuclear coupling effects into consideration.     

The Versatile,Efficient, and Stereoselective Self‐Assembly of Transition‐Metal Helicates by Using Hydrogen‐Bonds

A diverse range of dinuclear double‐stranded helicates in which the ligand strand is built up by using hydrogen‐bonding has been synthesized. The helicates, formulated as [Co₂(L)₂(L‐H)₂X₂], readily self‐assemble from a mixture of a suitable pyridine–alcohol compound (L; for example, 6‐methylpyridine‐2‐methanol, 1 ), and a CoX₂ salt in the presence of base. Nine such helicates have been characterized by X‐ray crystallography. For helicates derived from the same pyridine–alcohol precursor, a remarkable regularity was found for both the molecular structure and the crystal packing arrangements, regardless of the nature of the ancillary ligand (X). A notable exception was observed in the solid‐state structure of [Co₂( 1 )₂( 1 ‐H)₂(NCS)₂] for which intermolecular nonbonded contacts between the sulfur atoms (S???S=3.21 Å) lead to the formation of 1D chains. Helicates derived from (R)‐6‐methylpyridine‐2‐methanol ( 2 ) are soluble in solvents such as CH₃CN and CH₂Cl₂, and their self‐assembly could be monitored in solution by ¹H NMR, UV/Vis, and CD titrations. No intermediate complexes were observed to form in a significant concentration at any point throughout these titrations. The global thermodynamic stability constant of [Co₂( 2 )₂( 2 ‐H)₂(NO₃)₂] was calculated from spectrophotometric data to be logβ=8.9(8). The stereoisomerism of these helicates was studied in some detail and the self‐assembly process was found to be highly stereoselective. The chirality of the ligand precursors can control the absolute configuration of the metal centers and thus the overall helicity of the dinuclear assemblies. Furthermore, the enantiomers of rac‐6‐methylpyridine‐2‐methanol ( 3 ) undergo a self‐recognition process to form exclusively homochiral helicates in which the four pyridine–alcohol units possess the same chirality.     

Diastereoselective self-assembly of double- and triple-stranded helicates from a D-isomannide derivative

Difunctionalization of D-isomannide yielded a bis(bipyridine) ligand bearing four stereogenic centers whose diastereoselective self-assembly to enantiomerically pure dinuclear helicates upon coordination to different metal ions was investigated by NMR and CD spectroscopic as well as ESI mass spectrometric methods.     

Two Discrete Cu-Complexes Constructed from a Multidentate N-Containing Dinucleating Ligand

Two comparable discrete complexes [CuⅡ(CH3CN)2L2]·2(ClO4) 1 and [CuI2I2L2]·(DMF)2 2 were successfully synthesized by the reaction of CuⅡ and CuⅠ salts with a novel dinucleating ligand 2,5-bis(3-pyridinylmethylthio)-1,3,4-thiadiazole)(L),respectively.Complex 1 presents a single nuclear structure while 2 has a dimeric structure where two CuI ions are doubly bridged by halide ions in a μ2-fashion.Both discrete molecules were outspreaded into a one-dimensional supramolecular chain via aromatic interactions such as C-H…π and π…π interactions.     

1,3-二(4-吡啶基)-丙烷与邻苯二甲酸构筑的过渡金属配合物的合成、结构和荧光性质

以1,3-二(4-吡啶基)-丙烷(bpp)和邻苯二甲酸(1,2-H2bdc)为配体,通过水热法合成了过渡金属配合物M2(1,2-bdc)2(bpp)2·2H2O[M=Co(1),Ni(2)]和Cd(1,2-bdc)(bpp)·H2O(3).配合物1和2属单斜晶系P21空间群,具有相似的三维骨架结构.配合物中存在2种配位环境相似的金属中心,每个金属中心采取六配位的畸变八面体构型,与来自2个1,2-bdc配体的3个氧原子和2个bpp配体的2个氮原子以及1个水分子配位.1,2-bdc配体采取单齿/双齿螯合的配位模式将金属离子连接成M1-(1,2-bdc)-M2右手螺旋链.bpp配体采取Trans-Gauche(TG)构型,连接相邻的金属离子形成M1-(bpp)-M1链和M2-(bpp)-M2链.这3种链交织在一起构筑成具有{65.8}拓扑的三维结构.配合物3属单斜晶系P21/c空间群,具有单节点的双层二维结构.Cd(Ⅱ)离子采取七配位的畸变五角双锥体构型,与来自2个1,2-bdc配体的4个氧原子,2个bpp配体的2个氮原子和1个水分子配位.1,2-bdc配体采取双齿螯合/双齿螯合的配位模式将Cd(Ⅱ)离子连接成Cd-(1,2-bdc)-Cd链.bpp配体采取TG构型,连接相邻的Cd(Ⅱ)离子,形成Cd-(bpp)-Cd链.这2种链通过共享Cd(Ⅱ)离子交错排列构筑成二维结构.配合物3显示出强的荧光,最大发射位于408 nm处,对应于配体的π*-π跃迁.不同有机小分子对配合物3的荧光强度有不同程度的影响,苯胺对其有显著的猝灭作用,基于荧光猝灭机理,配合物3可用于选择性检测苯胺分子.     

新型环状金属Pt(Ⅱ)配合物:合成、晶体结构及光谱性质

合成了一种新的环状金属配体4-甲氧甲酰基-6-(4-甲基苯基)-2,2’-联吡啶(HL)及它的单核与双核Pt(Ⅱ)配合物[Pt(L)PPh₃](ClO₄)(1)与[Pt₂L₂(μ-dppm)](ClO₄)₂(2)(dppm=二(二苯基磷)-甲烷),并研究了它们的结构及光物理性质.配合物2的晶体结构分析表明,中心金属离子Pt(Ⅱ)呈扭曲平面正方形构型,桥配体dppm连接两个金属中心,0.3375 nm的Pt——Pt距离表明双核配合物中存在金属-金属相互作用.两配合物在～450 nm处的肩峰归属于金属到配体的电荷转移(MLCT)吸收,在固体及溶液中均观测到强烈的光致磷光发射.配合物1在固态时620 nm的低能发射归属为³(π-π)跃迁,并暗示配合物1晶体结构中存在分子间配体-配体相互作用,然而在溶液中仅观察到³MLCT发射光谱,但配合物2在固态及溶液中都观察到明显的金属和金属相互作用到配体的电荷转移(³MMLCT)发射.     

1，2-环己二羧酸及芳香含氮配体的双核镉、锰配合物的合成和晶体结构

用水热法合成了两种新的配合物[Cd2(e,e-trans-chdc)2(bipy)2(H2O)2].H2O(1)和[Mn2(e,a-cis-chdc)2(phen)2(H2O)2].2H2O(2)(chdc=1,2-环己二羧酸,bipy=2,2′-联吡啶和phen=1,10-邻菲咯啉),用X-射线单晶衍射分析确定了配合物的晶体结构。配合物1和2均为双核分子。配合物1中,2个镉髤离子由2个1,2-环己二羧酸根以e,e-trans配位方式桥联,每个镉髤离子与1个2,2′-联吡啶的2个氮原子、2个1,2-环己二羧酸根的4个氧原子及1个水分子中的氧原子配位,形成了单帽变形三棱柱构型。配合物2中,2个锰髤离子由2个1,2-环己二羧酸根以e,a-cis配位方式桥联,每个锰髤离子与1个1,10-邻菲咯啉的2个氮原子、2个1,2-环己二羧酸根的3个氧原子及1个水分子中的氧原子配位,形成了畸变的八面体构型。配合物1和2分子之间都存在π-π堆积和O-H…O、C-H…O弱作用,进而将双核分子连接成三维超分子网络结构。配合物的荧光均来自于配体的荧光。     

Anion-dependent formation of helicates versus mesocates of triple-stranded M2L3 (M = Fe2+, Cu2+) complexes

A series of dinuclear triple-stranded complexes, [Fe(2)L(3)?X]X(6) [X = BF(4)(-) (1), ClO(4)(-) (2)], [Fe(2)L(3)?SO(4)](2)(SO(4))(5) (3), [Fe(2)L(3)?Br](BPh(4))(6) (4), Fe(2)L(3)(NO(3))Br(6) (5), and [Cu(2)L(3)?NO(3)](NO(3))(6) (6), which incorporate a central cavity to encapsulate different anions, have been synthesized via the self-assembly of iron(II) or copper(II) salts with the N,N'-bis[5-(2,2'-bipyridyl)methyl]imidazolium bromide (LBr) ligand. X-ray crystallographic studies (for 1-4 and 6) and elemental analyses confirmed the cagelike triple-stranded structure. The anionic guest is bound in the cage and shows remarkable influence on the outcome of the self-assembly process with regard to the configuration at the metal centers. The mesocates (with different configurations at the two metal centers) have formed in the presence of large tetrahedral anions, while helicates (with the same configuration at both metal centers) were obtained when using the relatively smaller spherical or trigonal-planar anions Br(-) or NO(3)(-).