Structure and photophysical and electrochemical properties of a copper porphyrin complex with a three-dimensional framework

2020 ◽  
Vol 76 (2) ◽  
pp. 133-138
Author(s):  
Wen-Tong Chen

Porphyrins and metalloporphyrins can generally show attractive structural motifs and interesting properties. A new copper porphyrin, namely poly[[μ-chlorido-[μ5-5,10,15,20-tetrakis(pyridin-4-yl)-21H,23H-porphine]tricopper(I)] [aquadichloridocopper(II)]], {[Cu3(C40H24N8)Cl][CuCl2(H2O)]} n (1), was synthesized by the self-assembly of copper chloride with 5,10,15,20-tetrakis(pyridin-4-yl)-21H,23H-porphine under solvothermal conditions. The structure of this copper porphyrin was characterized by single-crystal X-ray crystallography and elemental analysis. The porphyrin macrocycle shows a distorted saddle geometry, with the four pyrrole rings slightly distorted in an alternating mode either upwards or downwards. The copper ions show three-coordinated triangular and four-coordinated square-planar geometries. Every copper–porphyrin unit connects to 12 others via four μ4-bridging Cu2Cl moieties to complete the three-dimensional framework of compound 1, with isolated CuCl2(H2O) units located in the voids. This copper porphyrin displays a red photoluminescence. Electrochemical measurements showed that compound 1 has two redox waves (E 1/2 = −160 and 91 mV).

2019 ◽  
Vol 75 (1) ◽  
pp. 8-14 ◽  
Author(s):  
Zhen Chen ◽  
Yanwen Sun ◽  
Zi-an Liu ◽  
Ning Wang ◽  
Xue Yang ◽  
...  

In recent years, coordination polymers constructed from multidentate carboxylate ligands and N-containing ligands have attracted much attention since these ligands can adopt a rich variety of coordination modes which can lead to crystalline products with intriguing structures and interesting properties. A new coordination polymer, namely poly[[diaqua[μ-2,7-bis(1H-imidazol-1-yl)fluorene-κ2 N 3:N 3′][μ-5,5′-methylenebis(3-carboxy-2,4,6-trimethylbenzoato)-κ2 O 1:O 1′]zinc(II)] hemihydrate], {[Zn(C23H22O8)(C19H14N4)(H2O)2]·0.5H2O} n , 1, was prepared by the self-assembly of Zn(NO3)2·6H2O with 5,5′-methylenebis(2,4,6-trimethylisophthalic acid) (H4BTMIPA) and 2,7-bis(1H-imidazol-1-yl)fluorene (BIF) under solvothermal conditions. The structure of 1 was determined by elemental analysis, single-crystal X-ray crystallography, powder X-ray diffraction, IR spectroscopy and thermogravimetric analysis. Each ZnII ion is six-coordinated by two O atoms from two H2BTMIPA2− ligands, by two N atoms from two BIF ligands and by two water molecules, forming a distorted octahedral ZnN2O4 coordination geometry. Adjacent ZnII ions are linked by H2BTMIPA2− ligands and BIF ligands, leading to the formation of a two-dimensional (2D) (4,4)-sql network, and intermolecular hydrogen-bonding interactions connect the 2D layer structure into the three-dimensional (3D) supramolecular structure. Each 2D layer contains two kinds of helices with the same direction, which are opposite in adjacent layers. The luminescence properties of complex 1 in the solid state have also been investigated.


2019 ◽  
Vol 75 (7) ◽  
pp. 990-995 ◽  
Author(s):  
Wenlong Lan ◽  
Zhen Zhou ◽  
Fu-Chao Jia ◽  
Xiaoyun Hao ◽  
Yong Dou ◽  
...  

A new coordination polymer (CP), namely poly[(μ-4,4′-bipyridine)(μ3-3,4′-oxydibenzoato)cobalt(II)], [Co(C14H8O5)(C10H8N2)] n or [Co(3,4′-obb)(4,4′-bipy)] n (1), was prepared by the self-assembly of Co(NO3)2·6H2O with the rarely used 3,4′-oxydibenzoic acid (3,4′-obbH2) ligand and 4,4′-bipyridine (4,4′-bipy) under solvothermal conditions, and has been structurally characterized by elemental analysis, IR spectroscopy, single-crystal X-ray crystallography and powder X-ray diffraction (PXRD). Single-crystal X-ray diffraction reveals that each CoII ion is six-coordinated by four O atoms from three 3,4′-obb2− ligands, of which two function as monodentate ligands and the other as a bidentate ligand, and by two N atoms from bridging 4,4′-bipy ligands, thereby forming a distorted octahedral CoN2O4 coordination geometry. Adjacent crystallographically equivalent CoII ions are bridged by the O atoms of 3,4′-obb2− ligands, affording an eight-membered Co2O4C2 ring which is further extended into a two-dimensional [Co(3,4′-obb)] n sheet along the ab plane via 3,4′-obb2− functioning as a bidentate bridging ligand. The planes are interlinked into a three-dimensional [Co(3,4′-obb)(4,4′-bipy)] n network by 4,4′-bipy ligands acting as pillars along the c axis. Magnetic investigations on CP 1 disclose an antiferromagnetic coupling within the dimeric Co2 unit and a metamagnetic behaviour at low temperature resulting from intermolecular π–π interactions between the parallel 4,4′-bipy ligands.


1984 ◽  
Vol 37 (7) ◽  
pp. 1395 ◽  
Author(s):  
BF Hoskins ◽  
IAS Mcdonald

The crystal and molecular structure of the 1-propylimidazolate bridged binuclear complex, LPd2(primid) has been determined by single-crystal X-ray diffraction techniques at 20�C; disordered ethanol molecules are also present in the lattice. The quinquedentate ligand L3- is formally the trianion α,α'-{(2-mercapto-4-methylbenzene-1,3-diyl)di(methylidyne)di(azino)bis(cyclohexane-methanol)ato(3 -). Crystals of LPd2 (primid) are triclinic, P1, with a 7.078(2), b l3.615(3), c 17365(3) �, α 78.52(2), β 80.21(2) and γ 83.83(2)�. The structure was solved by conventional Fourier methods and refined by full-matrix least-squares procedures to convergence with R and Rw 0.053 obtained for the 4133 statistically significant structure amplitudes. The ligand sidearms are essentially equivalent with both palladium centres displaying similar distorted square-planar geometries, the separation being 3.605 �. The propylimidazolate bridging group is comfortably accommodated within the binuclear framework and displays a geometry typical of metal complexes of imidazole and its derivatives. Coordination to the palladium centres occurs through C4 and N3, a bridging mode not previously characterized by X-ray crystallography, and one which illustrates the remarkable stability and flexibility of the binuclear LPd2+ core.


2016 ◽  
Vol 69 (5) ◽  
pp. 524 ◽  
Author(s):  
J. Wolfram Wielandt ◽  
Simon Petrie ◽  
Nathan L. Kilah ◽  
Anthony C. Willis ◽  
Rian D. Dewhurst ◽  
...  

Square-planar halide complexes in which four trimethylphosphine-stabilized diphenyl-stibenium or -bismuthenium ions surround a central halide ion in discrete centrosymmetrical structures of C4h symmetry have been isolated and their structures determined by X-ray crystallography. The structures are stabilized by electrostatic interactions between the halide ion and four positively charged trimethylphosphine-stabilized diphenyl-stibenium or -bismuthenium ions, as well as four edge-to-face phenyl–phenyl embraces above and below the plane containing the nine main group elements. The parent halide-free trimethylphosphine-stabilized diphenyl-arsenium, -stibenium, and -bismuthenium hexaflurophosphate complexes have also been prepared and structurally characterized.


Author(s):  
S. Cusack ◽  
J.-C. Jésior

Three-dimensional reconstruction techniques using electron microscopy have been principally developed for application to 2-D arrays (i.e. monolayers) of biological molecules and symmetrical single particles (e.g. helical viruses). However many biological molecules that crystallise form multilayered microcrystals which are unsuitable for study by either the standard methods of 3-D reconstruction or, because of their size, by X-ray crystallography. The grid sectioning technique enables a number of different projections of such microcrystals to be obtained in well defined directions (e.g. parallel to crystal axes) and poses the problem of how best these projections can be used to reconstruct the packing and shape of the molecules forming the microcrystal.Given sufficient projections there may be enough information to do a crystallographic reconstruction in Fourier space. We however have considered the situation where only a limited number of projections are available, as for example in the case of catalase platelets where three orthogonal and two diagonal projections have been obtained (Fig. 1).


1988 ◽  
Vol 21 (4) ◽  
pp. 429-477 ◽  
Author(s):  
W. Kühlbrandt

As recently as 10 years ago, the prospect of solving the structure of any membrane protein by X-ray crystallography seemed remote. Since then, the threedimensional (3-D) structures of two membrane protein complexes, the bacterial photosynthetic reaction centres of Rhodopseudomonas viridis (Deisenhofer et al. 1984, 1985) and of Rhodobacter sphaeroides (Allen et al. 1986, 1987 a, 6; Chang et al. 1986) have been determined at high resolution. This astonishing progress would not have been possible without the pioneering work of Michel and Garavito who first succeeded in growing 3-D crystals of the membrane proteins bacteriorhodopsin (Michel & Oesterhelt, 1980) and matrix porin (Garavito & Rosenbusch, 1980). X-ray crystallography is still the only routine method for determining the 3-D structures of biological macromolecules at high resolution and well-ordered 3-D crystals of sufficient size are the essential prerequisite.


2007 ◽  
Vol 62 (9) ◽  
pp. 1133-1138 ◽  
Author(s):  
Veli T. Kasumov ◽  
Ibrahim Uçar ◽  
Ahmet Bulut ◽  
Fevzi Kösal

The coordination chemistry of N-(2,6-di-methylphenyl)-2-hydroxy-3-methoxybenzaldimine (1) with Cu(II) has been investigated by X-ray crystallography, electronic and EPR spectroscopies, as well as by electro- and magnetochemistry. The title complex 2 crystallizes in the orthorhombic space group P212121 (a = 8.1538, b = 17.7466, c =19.8507 Å). The mononuclear square-planar molecules 2 featuring trans-N2O2 coordination are connected via weak intermolecular C-H· · ·π interactions into infinite chains parallel to the a axis. Although the intermolecular Cu· · ·Cu separations within individual chains and between chains are very long (8.154 and 9.726 Å ), the exchange interaction parameter G = 2.03 < 4, estimated from solid state EPR spectra, suggests the existence of long-distance superexchange pathways between adjacent Cu(II) centers. The electronic and electrochemical features of the compound are also discussed.


2002 ◽  
Vol 30 (4) ◽  
pp. 521-525 ◽  
Author(s):  
O. S. Makin ◽  
L. C. Serpell

The pathogenesis of the group of diseases known collectively as the amyloidoses is characterized by the deposition of insoluble amyloid fibrils. These are straight, unbranching structures about 70–120 å (1 å = 0.1 nm) in diameter and of indeterminate length formed by the self-assembly of a diverse group of normally soluble proteins. Knowledge of the structure of these fibrils is necessary for the understanding of their abnormal assembly and deposition, possibly leading to the rational design of therapeutic agents for their prevention or disaggregation. Structural elucidation is impeded by fibril insolubility and inability to crystallize, thus preventing the use of X-ray crystallography and solution NMR. CD, Fourier-transform infrared spectroscopy and light scattering have been used in the study of the mechanism of fibril formation. This review concentrates on the structural information about the final, mature fibril and in particular the complementary techniques of cryo-electron microscopy, solid-state NMR and X-ray fibre diffraction.


CrystEngComm ◽  
2017 ◽  
Vol 19 (38) ◽  
pp. 5755-5763 ◽  
Author(s):  
Feng Liu ◽  
Wei Gao ◽  
Xiu-Mei Zhang ◽  
Jie-Ping Liu ◽  
En-Qing Gao

Four coordination polymers with a new pyridyl-dicarboxylate ligand were synthesized under solvothermal conditions and studied by means of X-ray crystallography, topological analyses, luminescence and magnetic analyses.


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