The solvothermal reaction of 1-(3,5-dicarboxybenzyl)-4,4′-bipyridinium chloride (H2L+Cl–) with different anionic Zn(II) salts leads to three diverse metal–viologen complexes, formulated as {[Zn(HL)Cl2]2·2H2O} (1), {[Zn3(L)2(H2O)8]·2(SO4)·2(H2O)}n (2), and {[Zn(L)H2O]·NO3·H2O}n (3). Single-crystal X-ray analyses revealed that complex 1 displays dinuclear structure. Complex 2 features a 2D layered structure, which consists of four-fold interpenetrating stacked layers with sulfate ions locating between the sheets. Complex 3 shows a 3D two-fold interpenetrating framework with nitrate anions interspersing the void space of the framework, and it features an uninodal three-connected ThSi2 (ths) topology. The structural disparities reveal that the different geometries of counterions, coordination modes, and conformations of ligand L–, together with the deprotonation degree of aromatic carboxylate, have great influence on the formation of various structures. Interestingly, complexes 1–3 are all photoactive to UV–visible light and undergo obvious and reversible color transformations from light yellow to blue/green. Structural analyses indicated that not only the carboxylate-O donor and N acceptor of the bipyridinium moiety can provide an effective electron transfer pathway for photochromic behavior, but the Cl → L electron transfer in complex 1 also has a crucial effect on the photochromic behavior of it.

•Eight transition metal MOFs were synthesized based on a bipyridinium carboxylate ligand.•They exhibit five kinds of different structural types.•The structures range from 1D chain to 3D 2-fold interpenetrating frameworks.•Reaction temperatures and coordination modes of the ligand have a crucial influence on the architectures.•Solid-state photoluminescent properties of complexes 1–4 were investigated.Based on a bipyridinium carboxylate ligand 1-(3,5-dicarboxy)-benzyl-1,2-di(pyridine-4-yl)ethylene chloride (H2L+Cl−), eight transition metal coordination polymers, namely, {[Zn(L)Cl]⋅4H2O}n (1), {[Zn(L)H2O]⋅NO3⋅2H2O}n (2), {[Zn(L) (H2O)]⋅(NO3)0.5⋅(Cl)0.5⋅2H2O}n (3), {[Cd(L)(H2O)(NO3)]⋅2H2O}n (4), {[Cd1.5(L) (Cl)2]⋅2H2O}n (5), {[Cu(L)(H2O)]⋅NO3⋅H2O}n (6), {[Cu(HL)2(H2O)2]·Cl2·6H2O}n (7) and {[Ni(L)(H2O)Cl]⋅4H2O}n (8) have been synthesized and characterized by single-crystal X-ray diffraction analyses. Complexes 1 and 8 display 2D wave-like layer structures with a 3-connected 63 topology. Complexes 2 and 6 demonstrate 3D 2-fold interpenetrating frameworks with uninodal, 3-connected (10,3)-d utp-topology. Another pair of 3D 2-fold interpenetrating frameworks 3 and 4 possess 3-connected, uninodal 103 ThSi2 (ths)-topology. Complex 5 shows a 2D layer structure based on the extending of trinuclear Cd(II) subunits. Complex 7 presents 1D double-chain structure, in which the central Cu(II) ions are connected by the partially deprotonated ligand HL. Additionally, powder X-ray diffractions (PXRD) and thermogravimetric analyses of complexes 1–8, as well as the solid-state luminescent properties of d10 metal complexes 1–4 at room temperature have also been discussed.In this paper, based on a bipyridinium carboxylate ligand 1-(3,5-dicarboxy)-benzyl-1,2-di(pyridine-4-yl)ethylene chloride (H2L+Cl−), eight coordination polymers with five different architectures have been obtained. The result indicated that the structural characteristics of the H2L+ and the reaction temperature simultaneously play important roles in the final structures. Additionally, powder X-ray diffraction (PXRD) and thermogravimetric analyses of complexes 1–8, as well as the solid-state luminescent properties of d10 metal complexes 1–4 at room temperature have also been discussed.Download high-res image (306KB)Download full-size image

Three series of lanthanide coordination polymers, {[Ln(L)(H2O)2]·NO3·2H2O }n (Ln = La 1, Pr 2), {[Ln2(L)2(NO3)(H2O)2]·Cl·6H2O}n (Ln = Nd 3), {[Ln(L)(H2O)2]·Cl·3H2O}n (Ln = Sm 4, Eu 5, Gd 6, Tb 7, Dy 8, Ho 9, Er 10, Tm 11, Yb 12, and Lu 13) (H3L = 4-carboxy-1-(3,5-dicarboxy-benzyl)-pyridinium chloride), have been successfully synthesized under hydro(solvo)thermally conditions. Single-crystal X-ray diffraction analyses revealed that compounds 1–3 all crystallize in triclinic space group P1̅, but they display different three-dimensional structures with diverse dinuclear subunits. In contrast, compounds 4–13 display the same layer structures in the triclinic space group P1̅. The structural difference of these two classes of compounds is derived from the effect of lanthanide contraction. Powder X-ray diffraction (PXRD) and thermogravimetric analyses of compounds 1–13 have also been investigated and discussed in detail. The solid-state luminescent properties of compounds 4, 5, 7, and 8 were characterized, and the results revealed that they exhibit characteristic Sm(III), Eu(III), Tb(III), and Dy(III) emissions in the pink, red, green, and yellow light regions, respectively. More interestingly, the luminescence colors of the Tb(1–x)(L):xEu can easily be tuned from green to green-yellow, yellow, orange, and red-orange due to the energy transfer from Tb3+ to Eu3+ ions by adjusting the doping concentration of Eu3+ ions.

•Three coordination complexes based on mercapto-thiadiazole ligand were gained.•Complex 1 shows an in situ transformation of 4-Hptt into Hddc.•Complex 2 features a 2D grid layer.Three coordination complexes, namely, [Co(ddc)3] (1), [Zn(4-ptt)2·H2O]n (2) and [Pb(4-ptt)2]n (3), (Hddc = N,N-dimethyldithiocarbamic acid; 4-Hptt = 5-(4-pyridyl)-1,3,4-thiadiazole-2-thione) have been successfully synthesized under the same reaction conditions but tuned by different metal salts. Notably, in situ ligand reaction exists in the formation of complex 1, in which the ligand 4-Hptt reacted with DMF to generate the ligand Hddc. The X-ray single diffraction analysis reveals that 2 features a 2D layer structure, constructed from Zn(II) ions and 4-Hptt ligand. Complex 3 exhibits a 1D chain with 4-Hptt bridged four-coordinated Pb(II). Complexes 1–3 were characterized by elemental analyses, IR. The possible mechanism of the formation of Hddc for complex 1 has been discussed, and in addition, solid-state luminescent properties of polymers 2, 3 and ligand (4-Hptt) have also been investigated.One mononuclear complex [Co(ddc)3] (1), a 2D grid layer [Zn(4-ptt)2·H2O]n (2) and a 1D chain [Pb(4-ptt)2]n (3) were obtained. Notably, complex 1 shows an in situ transformation of 4-Hptt into Hddc. The possible mechanism of the formation of Hddc for complex 1 has been discussed, and solid-state luminescent properties of polymers 2, 3 and ligand (4-Hptt) have also been investigated.

•Solvothermal reactions were used to prepare four intriguing network with versatile 3-pttH ligand.•Complexes 1 and 2 feature similar novel two-fold interpenetrating 3D framework with 66-dia topology.•The mercapto-thiadiazole ligand can build complicated and intriguing networks.•Complex 1 displays good solid-state fluorescence property.By combining one kind of N-/S-containing rigid ligand with metal ions Zn(II), Co(II), Ni(II) and Pb(II), we have solvothermally synthesized four mercapto-thiadiazole based coordination polymers: [Zn(3-ptt)2]n (1), [Co(3-ptt)2]n (2), [Ni(3-ptt)2]n (3) and [Pb(3-ptt)2] (4) (3-pttH = 2-(3-pyridine)-1H-1,3,4-thiadiazole-5-thioketone). As a result of various coordination modes of the versatile 3-ptt, four complexes exhibit structural diversity. 1 and 2 exhibit similar novel twofold interpenetrating 3D supramolecular framework with 66-dia topology embodying two types of left- and right-handed single-helical chains, 3 displays an attractive interconnected 1D chain structure and 4 presents a mononuclear structure. We also investigated their thermogravimetric (TG) and luminescent properties. Complexes 1 and 4 show different luminescence properties in solid state at room temperature and may be suitable as a candidate for potentially photoactive material.Constructed from mercapto-thiadiazole ligand, two twofold penetrated 3D complexes [Zn(3-ptt)2]n (1) and [Co(3-ptt)2]n (2), an interconnected 1D complex [Ni(3-ptt)2]n (3) and one mononuclear complex [Pb(3-ptt)2] (4) were obtained. The thermal stabilities of complexes 1–4 and luminescence properties of the complexes and ligand in the solid state have also been investigated in detail.