Three coordination polymers constructed from bis(imidazol-l-yl-methyl)benzene: syntheses, structures, and third-order nonlinear optical properties

Crystal structures and investigation of the third-order nonlinear optical properties of four coordination polymers by using the Z-scan technique

Four coordination polymers with different structures are reported. They exhibit different third-order nonlinear optical activities.

Crystal structure of catena-(bis(μ2-1, 2-bis(imidazole-1-ylmethyl)benzene-κN:N′)-dichlororido-nickel(II)), C28H28Cl2N8Ni

C28H28Cl2N8Ni, monoclinic, P21/c, a = 8.521(5) Å, b = 10.255(6)) Å, c = 15.414(9) Å, β = 91.209(9)°, V = 1346.6(13) Å3, Z = 2, R gt(F) = 0.0360, wR ref(F 2) = 0.0916, T = 296(2) K.

Crystal structure of poly-[(μ6-benzene-1,2,4,5-tetracarboxylato)-(μ2-1,2-bis(imidazol-1-ylmethyl)benzene)dicobalt(II)], Co2C24H16N4O8

Co2C24H16N4O8, triclinic, P1̅ (no. 2), a = 7.3859(13) Å, b = 9.5719(17) Å, c = 16.442(3) Å, α = 77.450(3)°, β = 85.065(3)°, γ = 84.844(3)°, V = 1127.4(3) Å3, Z = 2, R gt(F) = 0.0457, wR ref(F2) = 0.1058, T = 296(2) K.

Nonlinear optical properties, upconversion and lasing in metal–organic frameworks

The building block modular approach that lies behind coordination polymers (CPs) and metal–organic frameworks (MOFs) results not only in a plethora of materials that can be obtained but also in a vast array of nonlinear optical properties that could be aimed at.

Structure and third-order nonlinear optical properties of the two-dimensional CoIIcoordination polymer [Co(1,2-BIB)(PA)]n{1,2-BIB is 1,2-bis[(1H-imidazol-1-yl)methyl]benzene and H2PA is phthalic acid}

The design of nonlinear optical (NLO) materials with large NLO responses has been a challenge for materials scientists and chemists. Recently, organic polymers have received attention regarding their NLO properties and fast nonlinear response, and clusters involving delocalizeddπ–pπ systems and conjugateddπ–pπ systems are expected to be a new class of NLO materials. Metal–organic coordination polymers combine the advantages of the organic and inorganic species. Thus far, tuning the third-order NLO properties of these materials has been a significant challenge. A two-dimensional coordination polymer, namely poly[(μ-benzene-1,2-dicarboxylato-κ3O1,O1′:O3){μ-1,2-bis[(1H-imidazol-1-yl)methyl]benzene-κ2N3:N3′}cobalt(II)], [Co(C8H4O4)(C14H14N4)]n, was synthesized by hydrothermal methods. In the structure, the CoIIion is pentacoordinated by two N atoms from two different 1,2-bis[(1H-imidazol-1-yl)methyl]benzene (1,2-BIB) ligands and three O atoms from two symmetry-related benzene-1,2-dicarboxylate (isophthalate, PA) anions. The pentacoordinated CoIIions are linked by PA ligands to form a chain structure parallel to thecaxis. Adjacent chains are further connected by 1,2-BIB ligands to produce a two-dimensional layered structure. The compound exhibits strong third-order nonlinear absorption and nonlinear refraction effects as a thin film. The third-order susceptibility χ(3)is calculated to be 1.07 × 10−8esu, which is much larger than the values found for pure inorganic semiconductors and some polymers.

Biphenyl-2,4,6,3',5'-pentacarboxylic acid as a tecton for six new Co(II) coordination polymers: pH and N-donor ligand-dependent assemblies, structure diversities and magnetic properties

Six new Co(ii)-based mixed-ligand coordination polymers, namely, [Co2(H3bppc)2(2,2'-bpy)4]·H2O (), [Co2(Hbppc)(2,2'-bpy)2(H2O)]·H2O (), [Co(H2bppc)(H-bpp)]·2H2O (), [Co3(μ3-OH)(bppc)(dps)(CH3CH2OH)]·4H2O (), [Co2(bppc)(bib)(H2O)4]·(H2-bib)0.5·(H2O)3 (), and [Co2(Hbppc)(bix)2]·2H2O (), (H5bppc = biphenyl-2,4,6,3',5'-pentacarboxylic acid, 2,2'-bpy = 2,2'-bipyridine, bpp = 1,3-bis(4-pyridyl)propane, dps = 4,4'-sulfanediyldipyridine, bib = 1,4-bis(imidazol-1-yl)benzene, bix = 1,4-bis(imidazol-1-ylmethyl)benzene), have been obtained under solvothermal conditions. exhibits a 3D supramolecular framework based on a [Co2(H3bppc)2(2,2'-bpy)4] unit. has a (3,4)-connected dmc net with a (4·8(2))(4·8(5)) topology containing alternate binuclear metal clusters and single metal centres. shows a 3D supramolecular architecture constructed from ladder-like arrays decorated with H-bpp. exhibits a binodal (5,7)-connected 3D network based on trinuclear [Co3(μ3-OH)](5+) units with an unusual (3·4(6)·5(2)·6)(3(2)·4(6)·5(7)·6(5)·7) topology. features a (4,6)-connected 3D fsc open framework with binuclear [Co2(H2O)(COO)](3+) units as nodes, and H2-bib and water molecules located in the voids of its framework by hydrogen bonds. possesses a 3D net containing unusual 2D polyrotaxane sheets. Topological analysis reveals that has a (3,4,4)-connected 3D network with a (4·6·7(4))(4·6·7)(6·7(2)·10(2)·11) topology. The structural difference of and is due to the different pH values of the reaction system. Though complexes were synthesised under similar reaction conditions, the carboxylic groups of H5bppc were partially deprotonated in , and and fully deprotonated in and . Complexes display diverse structures depending on different N-donor ligands and the coordination modes of the multicarboxylate ligand. Variable-temperature magnetic susceptibility measurements reveal that complexes show antiferromagnetic interactions.