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Wenbin Lin

Publications and source records attributed to Wenbin Lin.

46 records · Page 3Linked to original sources
PubMed2002

Well-defined enantiopure 1,1'-binaphthyl-based oligomers: synthesis, structure, photophysical properties, and chiral sensing.

A series of well-defined enantiopure 1,1'-binaphthyl-based oligomers linked through their 6,6'-positions, ranging from quaternaphthol to decanaphthol, have been synthesized by Suzuki and Stille coupling reactions. These novel oligonaphthyls have been characterized by (1)H and (13)C[(1)H] NMR spectroscopy and high-resolution mass spectrometry. A combination of X-ray structural and CD studies suggests that these oligonaphthyls adopt zigzag but not helical conformations. As the chain length increases, the compounds show enhanced fluorescence. The fluorescence intensity of oligonaphthols is almost 2 orders of magnitude higher than that of 1,1'-bi-2-naphthol and can be effectively and enantioselectively quenched with trans-1,2-diaminocyclohexane with an enantioselectivity factor of 1.24. The present work thus demonstrates the potential of constructing chiral sensory materials based on well-defined enantiopure oligonaphthols.

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PubMed2002

Nonlinear optically active polymeric coordination networks based on metal m-pyridylphosphonates.

A family of polymeric coordination networks based on meta-pyridylphosphonate bridging ligands has been synthesized and characterized by single-crystal X-ray crystallography. Compounds [M(2)(L-Et)(4)(mu-H(2)O)] (M = Mn, 1; Co, 2; Ni, 3; L-Et = ethyl-4-[2-(3-pyridyl)ethenyl]phenylphosphonate) were obtained by hydro(solvo)thermal reactions between diethyl-4-[2-(3-pyridyl)ethenyl]phenylphosphonate (L-Et(2)) and corresponding metal salts, while [Cd(L-H)(2)], 4 (L-H is monoprotonated 4-[2-(3-pyridyl)ethenyl]phenylphosphonate), was obtained by a hydro(solvo)thermal reaction between (L-H(2)).HBr and Cd(CF(3)SO(3))(2).6H(2)O. Compounds 1-3 are isostructural and crystallize in noncentrosymmetric space group Fdd2, and they adopt a complicated 3D framework structure composed of [M(2)(L-Et)(4)(mu-H(2)O)] building units, while compound 4 adopts a centrosymmetric 3D network structure resulted from linking 1D sinusoidal cadmium phosphate chains with L-H bridging ligands. Consistent with their polar structures, compounds 1-3 exhibit powder second harmonic generation signals larger than that of potassium dihydrogen phosphate.

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PubMed2002

A novel coordination polymer containing both interdigitated 1D chains and interpenetrated 2D grids.

A hydro(solvo)thermal reaction between zinc perchlorate and ethyl ester of a new pyridinecarboxylate bridging ligand of approximately 17.6 A in length yields a unique coordination polymer which contains both interdigitated infinite 1D chains and interpenetrated 2D rhombohedral grids [Zn(2.5)(L)(4)(mu(3)-OH)] x (H(2)O)(5), 1, where L is 3-[[4-(4-pyridylethenyl)phenyl]ethenyl]benzoate. The 1D chains contain mu(3)-bridged hydroxy groups and have a [Zn(4)(mu(3)-OH)(2)(L)(6)] stoichiometry, while the 2D grids have a Zn(L)(2) formula and diagonal distances of 31.7 and 25.2 A. Crystal data for 1: monoclinic space group P2/c, a = 15.686(2) A, b = 12.6103(16) A, c = 38.999(5) A, beta = 98.397(2) degrees, and Z = 4.

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PubMed2002

Chiral hybrid metal-organic dendrimers.

[structure: see text] New chiral terpyridines containing Frechét-type dendrons have been readily synthesized by coupling dendritic benzyl bromide and 4'-[6-(2,2'-dihydroxy-1,1'-binaphthyl)]-2,2':6'2' '-terpyridine. These chiral dendritic terpyridines were used to efficiently construct high molecular weight hybrid metal-organic dendrimers based on the Ru(II)-bis(terpy) linkage. Preliminary fluorescence measurements show generation-dependent fluorescence quenching behavior of 3,5-dimethoxybenzyl peripherals by the [Ru(terpy)(2)](2+) unit.

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PubMed2002

A chiral molecular square with metallo-corners for enantioselective sensing.

A family of chiral molecular squares based on fac-Re(CO)3Cl metallocorners and enantiopure atropisomeric bipyridine bridging ligands (L1-4) have been synthesized in high yields by refluxing ClRe(CO)5 and L1-4 in 1:1 molar ratio. These novel chiral metallocycles have been characterized by 1H and 13C{1H} NMR, UV-vis, luminescence, and circular dichroism (CD) spectroscopies, FAB mass spectrometry, and microanalysis. Molecular square 4 which contains four 1,1'-bi-2-naphthol functionalities exhibits interesting enantioselective luminescence quenching by 2-amino-1-propanol. This research illustrates the potential of generating novel functional materials based on supramolecular chemistry.

Circular Dichroism↗
PubMed2002

New rigid angular dicarboxylic acid for the construction of nanoscopic supramolecules: from a molecular rectangle to a 1-D coordination polymer.

A new rigid angular bridging ligand, 7-oxa-dibenzofluorene-3,11-dicarboxylic acid (H(2)L), was synthesized by cyanation of known rac-6,6'-dibromo-1,1'-bi-2-naphthol followed by ring closure and hydrolysis with concentrated sulfuric acid and used for the self-assembly of nanoscopic molecular rectangle [Cu(4)(L)(4)(Py)(8)].2DMF.10H(2)O, 1, and 1-D coordination polymer [Co(2)(L)(2)(Py)(4)].2DMF.2H(2)O, 2. Both 1 and 2 contain open channels occupied by DMF and water guest molecules. Crystal data for 1:[?] triclinic, space group P(-)1, a = 8.869(2) A, b = 16.437(3) A, c = 21.586(4) A, alpha = 78.18(3), beta = 79.19(3), gamma = 83.66(3), U = 3017.0(11) A(3), and Z = 1. Crystal data for 2: triclinic, space group P(-)1, a = 8.254(2) A, b = 12.154(2) A, c = 15.348(3) A, alpha = 95.34(3), beta = 93.38(3), gamma = 94.37(3), U = 1525.1(5) A(3), and Z = 1.

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PubMed2002

Crystal engineering of NLO materials based on metal--organic coordination networks.

Crystal engineering, the ability to predict and control the packing of molecular building units in the solid state, has attracted much attention over the past three decades owing to its potential exploitation for the synthesis of technologically important materials. We present here the development of crystal-engineering strategies toward the synthesis of noncentrosymmetric infinite coordination networks for use as second-order nonlinear optical (NLO) materials. Work performed mainly in our laboratory has demonstrated that noncentrosymmetric solids based on infinite networks can be rationally synthesized by combining unsymmetrical bridging ligands and metal centers with well-defined coordination geometries. Specifically, coordination networks based on 3D diamondoid and 2D grid structures can be successfully engineered with a high degree of probability and predictability to crystallize in noncentrosymmetric space groups. We have also included noncentrosymmetric solids based on 1D chains and related helical structures for comparison.

Journal Article↗
PubMed1999

Nanoporous, Interpenetrated Metal-Organic Diamondoid Networks.

Reactions of Cd(NO(3))(2).4H(2)O with 4-cyanopyridine in the presence of ethanol or pyrazine guest molecules under hydro(solvo)thermal conditions afford two new cadmium coordination polymers, [Cd(isonicotinate)(2)(EtOH)][EtOH], 1, and [Cd(isonicotinate)(2)(H(2)O)][pyrazine], 2. The Cd centers in both 1 and 2 are seven-coordinate with distorted pentagonal bipyrimidal structures via coordination to two pyridyl nitrogen atoms, one oxygen atom from a solvent molecule, one chelating carboxylate, and one semichelating carboxylate group. The bridging isonicotinate groups link each Cd center to four adjacent Cd centers, resulting in three-dimensional polymeric networks based on doubly interpenetrated diamondoid structures. One molecule of ethanol or pyrazine is also included in 1 or 2, respectively, to fill the void space left within the solid after the twofold interpenetration. Thermogravimetric analyses (TGA) showed that the included and coordinated ethanol molecules in 1 could be removed stepwise at 100 and 160 degrees C, respectively. After the removal of the guest ethanol molecules, the resulting nanoporous solid exhibits the same X-ray powder diffraction (XRPD) pattern as 1. Guest ethanol molecules can be reintroduced into the evacuated sample of 1 via exposure to ethanol vapor at room temperature. Further heating results in the loss of coordinated ethanol molecules and the collapse of the polymeric network structure. On the other hand, XRPD shows that removal of pyrazine in 2 is accompanied by the loss of the coordinated water molecules and, consequently, the collapse of the polymeric network structure. These results demonstrate that nanopores can be designed based on interpenetrated coordinated networks. Crystal data for 1: orthorhombic space group Pbca, a = 12.691(1) Å, b = 15.545(1) Å, c = 18.342(1) Å, and Z = 8. Crystal data for 2: orthorhombic space group Pbca, a = 12.081(1) Å, b = 15.323(2) Å, c = 19.705(3) Å, and Z = 8.

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