Self-assembly of homochiral porous solids based on 1D cadmium(II) coordination polymers

A family of homochiral 1D cadmium(II) coordination polymers based on the (S)-2,2'-dimethoxy-1,1'-binaphthyl-3,3'-bis(4-vinylpyridine) (L) bridging ligand were synthesized from the same building blocks under slightly different conditions, and characterized by single-crystal X-ray crystallography. While [CdL(DMF)4](ClO4)2 x EtOH x 0.5H2O (1) adopts a 1D zigzag chain structure, [CdL2(ClO4)2] x 3EtOH x H2O (2) and [CdL2(ClO4)(H2O)] (ClO4) x 1.5(o-C6H4Cl2) x 3EtOH x 6H2O (3) both exhibit 1D polymeric structures that are built from 38-membered macrocycles. These 1D coordination polymers further pack into chiral porous frameworks via pi...pi interactions with a large percentage of void spaces that are occupied by solvent molecules and counterions.     

Two new cadmium(II) coordination polymers with bis(benzimidazole) ligands

Two new cadmium(II) coordination polymers, {[Cd(L1)(tbta)]·H₂O} _n (1) and [Cd(L2)(tbta)] _n (2) (L1 = 1,4-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene, H₂tbta = tetrabromoterephthalic acid and L2 = 1,4-bis(2-methylbenzimidazol-1-ylmethyl)benzene) are obtained under hydrothermal conditions and structurally characterized by single crystal X-ray diffraction methods, IR spectroscopy, TGA and elemental analysis. The L1 and L2 ligands differ by subtle variation of substituents at semi-rigid bis(benzimidazole) bakcbones. Complex 1 features a 3D threefold interpenetrating dia array with a 4-connected 6⁶ topology. Complex 2 displays a 2D {4⁴.6²} sql/Shubnikov tetragonal plane network. Complexes 1 and 2 possess high thermal stabilities and promising fluorescence behavior in the solid state.     

Assembly,crystal structures,and luminescent properties of three new thiocyanate-bridging mercury(II) coordination polymers

Two ligands, 2-{5,5-dimethyl-3-[2-(pyridin-3-yl)-ethenyl]cyclohex-2-enylidene}propanedinitrile (L1) and 2-{5,5-dimethyl-3-[2-(pyridin-2-yl)-ethenyl]cyclohex-2-enylidene}propanedinitrile (L2), were synthesized. By reaction of mercury thiocyanate with L1 and L2, respectively, coordination polymers [Hg(L1)(μ_1,3-SCN)₂]_n (1), [Hg(L1)₂(μ_1,3-SCN)₂]_n (2), and [Hg(L2)(μ_1,3-SCN)(SCN)]_n (3) with different structures and topologies were obtained. In 1, the thiocyanate shows μ_1,3-SCN bridging coordination, and adjacent Hg(II) ions are bridged by two μ_1,3-SCN ions to form an infinite chain with the remaining position of five-coordinate Hg(II) occupied by L1. In 2, the thiocyanate has the same coordination as 1. However, Hg(II) has octahedral coordination with two L1 involved in coordination. An unusual feature of 3 is the presence of two types of thiocyanates, one has a S-terminal ligand and the other has a μ_1,3-SCN bridge. The mercury(II) in 3 is four-coordinated by L2 and three thiocyanates. Luminescent properties and thermal stabilities of 1–3 were studied.     

Hydrothermal synthesis,crystal structure and photoluminescence of two homochiral zinc(II) coordination polymers

Metal–organic frameworks (MOFs) have potentially useful applications and an intriguing variety of architectures and topologies. Two homochiral coordination polymers have been synthesized by the hydrothermal method, namely poly[(μ‐N‐benzyl‐L‐phenylalaninato‐κ⁴O,O′:O,N)(μ‐formato‐κ²O:O′)zinc(II)], [Zn(C₁₆H₁₆NO₂)(HCOO)]_n, (1), and poly[(μ‐N‐benzyl‐L‐leucinato‐κ⁴O,O′:O,N)(μ‐formato‐κ²O:O′)zinc(II)], [Zn(C₁₃H₁₈NO₂)(HCOO)]_n, (2), and studied by single‐crystal X‐ray diffraction, elemental analyses, IR spectroscopy and fluorescence spectroscopy. Compounds (1) and (2) each have a two‐dimensional layer structure, with the benzyl or isobutyl groups of the ligands directed towards the interlayer interface. Photoluminescence investigations show that both (1) and (2) display a strong emission in the blue region.     

Synthesis,structures, and fluorescence of two cadmium(II) coordination polymers with a semirigid bis-benzimidazole

Compounds [CdLCl₂] _n (1) and {[Cd(L)₂(ClO₄)]·ClO₄} _n (2), where L?=?1,3-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene, have been synthesized by hydrothermal method, and characterized by element analysis, IR spectra, Powder XRD, and X-ray crystallographic diffraction. Cd(II) in 1 and 2 are both trigonal bipyramidal. Different cadmium salts of chloride and perchlorate lead to different configurations of [Cd₂L₂]²⁺, trans-form in 1 but trans and cis-forms in 2. The 1-D beaded chains of 1 are further linked to generate a 3-D supramolecular architecture by strong π–π stacking interactions as well as intermolecular C–H?···?Cl hydrogen bonds. In 2, the 1-D beaded chains are further assembled by intermolecular C–H?···?O hydrogen bonds to form a 2-D layer. Solid-state fluorescent properties of 1 and 2 were investigated at room temperature.     

Syntheses,structures, and photoluminescence of three cadmium(II) coordination polymers with flexible bis(benzimidazole) ligands

Three cadmium(II) coordination polymers, [CdBr₂(L₁)] _n (1), [CdI₂(L₂)] _n (2), and Cd₂Br₄(L₃)₂ (3), where L₁?=?1,3-bis(5,6-dimethylbenzimidazole)propane, L₂?=?1,4-bis(5,6-dimethylbenzimidazole)butane, and L₃?=?1,6-bis(5,6-dimethylbenzimidazole)hexane, have been synthesized by hydrothermal methods and characterized by elemental analyses, IR spectra, TGA, PXRD, and X-ray crystallographic diffraction. Complex 1 contains a 1-D helical chain in which CdBr₂ units are linked by L₁. For 2, each CdI₂ is connected by two different conformations of L₂ to form a 1-D zigzag chain. For 3, each CdBr₂ is linked by L₃ bridges to afford a binuclear structure. These results indicate that the spacer length of the ligands play important roles in assembly of Cd(II) coordination polymers. Thermogravimetric analyses and solid-state luminescent properties of the complexes have also been investigated.     

Syntheses, structures and luminescent properties of zinc(II) and cadmium(II) coordination complexes based on new bis(imidazolyl)ether and different carboxylate ligands

A series of mixed-ligand coordination complexes, namely [Zn(CA)(2)(BIE)] (1), [Zn(OX)(BIE)].H(2)O (2), [Zn(2)(m-BDC)(2)(BIE)(2)] (3), [Cd(m-BDC)(BIE)] (4), [Cd(5-OH-m-BDC)(BIE)] (5), [Zn(5-OH-m-BDC)(BIE)] (6), [Zn(2)(p-BDC)(2)(BIE)(2)].2.5H(2)O (7), [Cd(3)(p-BDC)(3)(BIE)] (8), [Cd(3)(BTC)(2)(BIE)(2)].0.5H(2)O (9) and [Zn(BTCA)(0.5)(BIE)] (10), where CA = cinnamate anion, OX = oxalate anion, m-BDC = 1,3-benzenedicarboxylate anion, 5-OH-m-BDC = 5-OH-1,3-benzenedicarboxylate anion, p-BDC = 1,4-benzenedicarboxylate anion, BTC = 1,3,5-benzenetricarboxylate anion, BTCA = 1,2,3,4-butanetetracarboxylate anion, and BIE = 2,2'-bis(1H-imidazolyl)ether, were synthesized under hydrothermal conditions. In 1, a pair of BIE ligands bridge adjacent Zn(II) atoms to give a centrosymmetric dimer. In 2 and 3, BIE ligands connect Zn(II)-carboxylate chains to form hexagonal honeycomb 6(3)-hcb and square 4(4)-sql layers, respectively. In 4 and 5, m-BDC and 5-OH-m-BDC bridge Cd(II) atoms to give dimeric units, respectively, which are further linked by BIE ligands to form sql nets. In 6, the BIE ligands extend the Zn(II)-carboxylate chains into 2D sinusoidal-like sql nets. The undulated sql nets polycatenate each other in the parallel manner with DOC (degree of catenation) = 2, yielding a rare 2D --> 3D parallel polycatenation net. In 7, the BIE and p-BDC ligands link the Zn(ii) atoms to give a rare 3-fold interpenetrated 3-connected 10(3)-ths net. 8 contains unusual edge-sharing polyhedral rods formed by [Cd(3)(CO(2))(6)] clusters. Each rod is connected by the benzene rings of p-BDC in four directions into a simple alpha-Po topology. In 9, two kinds of different 2D Cd-BTC layers are alternately linked to each other by sharing Cd(ii) centers to form a 3D framework, which is further linked by two kinds of BIE ligand to produce a complicated 3D polymeric structure. 10 possesses a unique (3,4)-connected 3D framework with (8(3))(2)(8(5).10) topology. The structural differences described indicate the importance of carboxylate ligands and metals in the framework formation of coordination complexes. The infrared spectra, thermogravimetric and luminescent properties were also investigated in detail for the compounds.     

Syntheses, structures and luminescent properties of new lanthanide-based coordination polymers based on 1,4-benzenedicarboxylate (bdc)

Reaction of 1,4-benzenedicarboxylic acid (1,4-H(2)BDC) with EuCl(3).6H(2)O in MeOH in the presence of Et(3)N and MeCN gives a mixture of the 3-D metal-organic-framework (MOF) materials [Eu(2)(1,4-BDC)(3)(MeOH)(4)].8MeOH () and 2-D [Eu(1,4-BDC)(MeOH)(4)].Cl.MeOH.0.25H(2)O (). Similar reactions afforded the isomorphous Gd () and Tb () analogs of . Reaction of 1,4-H(2)BDC with Ln(NO(3))(3).6H(2)O under similar conditions gave [Ln(BDC)NO(3)(MeOH)(2)].MeCN.H(2)O (Ln = Eu () and Gd ()), which have 2-D framework structures. The structures of were determined by single crystal X-ray crystallographic studies and the luminescence properties of and in DMF solution were determined.     

New heterometallic coordination polymers based on zinc(II) complexes with Schiff-base ligands and dicyanometallates: synthesis,crystal structures,and luminescent properties

Four new d¹⁰ heterometallic coordination polymers have been obtained using three Schiff-base ligands, zinc(II) nitrate, and dicyanometallates: ₁^∞[{Zn₃(Salen)₂}{μ-Au(CN)₂}₂] (1); ₁^∞[Zn(Saldmen){μ-Ag(CN)₂}]·2H₂O (2); ₁^∞[Zn(Salampy){μ-Ag(CN)₂}] (3); ₁^∞[Zn(Salampy){μ-Au(CN)₂}] (4). The Schiff bases are obtained from condensation of salicylaldehyde with ethylenediamine (H₂Salen); N,N-dimethyl-ethylenediamine (HSaldmen) and, respectively, 2-aminomethyl-pyridine (HSalampy). The dicyanometallates are K[Ag(CN)₂] and K[Au(CN)₂]. The compounds were characterized by X-ray single-crystal diffraction, infrared spectroscopy, UV–vis spectroscopy, and elemental analysis. In compound 1, the homotrimetallic units, {Zn₃(salen)₂}²⁺, are connected by two [Au(CN)₂]^? bridges, forming a 1-D double chain. In compounds 2–4, the crystal structures show polymeric zigzag chains generated by the mononuclear zinc(II) nodes and [M(CN)₂]^? spacers. The luminescence properties of the new heterometallic polymers have also been investigated.     

Synthesis,structure and luminescent properties of a new two-dimensional (4,4) network cadmium coordination polymer with dicyanamide and benzimidazole ligands

The new cadmium coordination polymer [Cd(bim)₂(dca)₂]_n (1), (bim?=?benzimidazole, dca?= dicyanamide) was synthesized and characterized by IR, thermogravimetric analysis and luminescent properties. The coordination geometry of cadmium atom is distorted octahedral, coordinated equatorially by four nitrogen atoms from four dicyanamide ligands, and axially by two nitrogen atoms from two benzoimidazoles. Each dca ligand links two cadmium(II) atoms and 1 forms a two-dimensional (4,4) network.     

Syntheses, structures, and properties of zinc(II), cadmium(II), cobalt(II), and manganese(II) coordination polymers with tetraiodoterephthalate

The coordination chemistry of a rigid periodinated ligand, 2,3,5,6-tetraiodo-1,4-benzenedicarboxylic acid (H₂BDC-I₄), with a series of transition metal ions has been explored to afford five new coordination polymers {[M(BDC-I₄)(MeOH)₄](H₂BDC-I₄)(MeOH)₂} _n (M?=?Zn^II for 1, Cd^II for 2, Co^II for 3 and Mn^II for 4) and {[Mn(BDC-I₄)(MeOH)₄](DMF)} _n (5). All these complexes have been characterized by elemental analysis, IR spectroscopy, thermogravimetric (TG) analysis, and X-ray crystallography. Single-crystal X-ray diffraction reveals that complexes 1?C4 are isostructural and have a one-dimensional chain structure. Upon the addition of the solvent DMF, the infinite linear chain array in 4 is converted to a 1-D wave-like chain motif in 5 with a different space group ( $ P\overline{1} $ for 4 and P2₁/c for 5). The difference between structures 1?C4 and 5 can be attributed to the coordination mode of carboxylate changing from trans to cis fashion. The Zn^II and Cd^II complexes 1 and 2 display similar emissions in the solid state, which essentially are intraligand transitions.     

Manganese(II), nickel(II), and cadmium(II) coordination polymers with tetrafluoroterephthalate: syntheses,crystal structures,and luminescence properties

Three new coordination polymers, [Mn(BDC-F₄)(DMF)₂(H₂O)₂] _n (1), [Ni(BDC-F₄)(DMF)(EtOH)] _n (2), and [Cd(BDC-F₄)(DMF)(EtOH)] _n (3), have been synthesized by assembling transition metal salts with the rigid ligand tetrafluoroterephthalic acid (H₂BDC-F₄) in mixed EtOH/DMF solvent at pH ca. 2. For complex 1, the octahedral coordination geometry of the Mn^II center is provided by two oxygen atoms from two dianionic BDC-F₄ ligands, two DMF ligands and two aqua ligands, giving a 1-D linear chain array. For complex 2, the Ni^II center is coordinated by two dianionic BDC-F₄ ligands, two EtOH ligands and two DMF ligands, resulting in a 1-D chain structure. For complex 3, the Cd^II center is coordinated by four dianionic BDC-F₄ ligands, one EtOH ligand and one DMF ligand, generating a 2-D layered structure. The results suggest that both the metal and the solution pH play an important role in the formation of the complexes. The spectroscopic, thermal, and luminescence properties of the complexes have been investigated.     

Hydrothermal synthesis,crystal structures,and photoluminescent properties of two cadmium(II) coordination polymers derived from dicarboxylates and N-donor ligands

Two metal coordination polymers, [Cd(ipa)(L₁)(H₂O)]_n (1) and [Cd(ipa)(L₂)]_n (2) [H₂ipa?=?isophthalic acid, L₁?=?3,5-bis(imidazole-1-yl)pyridine and L₂?=?3,5-bis(benzoimidazo-1-ly)pyridine], have been synthesized and structurally characterized by IR, elemental analysis, XRD, and X-ray single-crystal diffraction. Complex 1 shows a twofold cds topological net and 2 features a 3-D pcu topological net. Luminescent properties of 1 and 2 were investigated in the solid state at room temperature.     

Two mixed-valence copper(I,II) imidazolate coordination polymers: metal-valence tuning approach for new topological structures

A new metal-valence tuning synthetic approach has been utilized to generate two new mixed-valence Cu(I,II) coordination polymers Cu(2)(im)(3) and Cu(3)(im)(4)(Him = imidazole), which are an unprecedented uninodal 4-connected 4.8(5) topological net and a 4-connected (4,4) net, respectively.     

Syntheses,crystal structures and luminescent properties of two new Zn(II) coordination polymers based on a dicarboxylate and different imidazole-containing ligands

To investigate the effect of different imidazole-containing ligands on the structure of coordination polymers, two new Zn(II) coordination polymers based on 1,4-cyclohexanedicarboxylic acid (H₂cda) and two different imidazole-containing ligands, [Zn(cda)(bib)_0.5]_n (1) and [Zn(cda)(bmib)_0.5]_n (2) (bib = 1,4-bis(imidazol-1-yl)benzene and bmib = 1,4-bis(2-methylimidazol-3-ium-yl)benzene), have been synthesized and characterized by single-crystal X-ray diffraction. Complex 1 shows a 3-D structure with point symbol (4.8².10³).(4.8²). Complex 2 displays a 2-D layer structure with an –AB– stacking sequence.     

Synthesis and characterization of zinc(II), copper(II) and cadmium(II) coordination polymers with tetrachloroterephthalate-based ligands

Three complexes, namely Zn(BDC-Cl₄)(py)₃ (1), Cu(BDC-Cl₄)(py)₃ (2) and Cd(BDC-Cl₄)(py)₃ (3) (BDC-Cl₄ = 2,3,5,6-tetrachloro-1,4-benzenedicarboxylate, py = pyridine) have been synthesized. Complexes (1) and (2) have been obtained using solvothermal methods. Both have a five-coordinate geometry with two bridging monodentate tetrachloroterephthalate ligands and three pyridine ligands coordinated to the Zn(II) or Cu(II) atom. The tetrachloroterephthalate ligands bridge the adjacent Zn(II) or Cu(II) centers, giving zigzag chains. Complex (3) has also been crystallized, each Cd(II) atom is six-coordinated to three carboxylate oxygen atoms and three pyridyl nitrogen atoms. Two types of tetrachloroterephthalate ligand, featuring monodentate and bidentate carboxylates, connect the Cd(II) centers to form zigzag chains. All three complexes have been subjected to thermogravimetric analysis.     

Synthesis and structural characterization of two dimensional cadmium(II) coordination polymers

Reactions of Cd(NO₃)₂?·?4H₂O with NH₄SCN, ppz (ppz?=?piperazine) and bpa (bpa?=?bis(4-pyridyl)ethane) in CH₃OH afforded the cavity-containing rectangular grids {Cd(SCN)₂(ppz)} _n (1) and {Cd(NCS)₂(bpa)} _n (2). The ppz ligand in 1 is coordinated to the metal through both nitrogen atoms to form the 1-D zig-zag chain structure and distorted {CdN₄S₂} octahedral coordination geometry at each Cd center is completed by pairs of bidentate thiocyanato ligands. Complex 2 has the 2-D arrangement constructed through 1-D double μ(N,S) end-to-end bridging thiocyanato groups bridging Cd(II) chains interconnected through disordered bpa ligands.     

Two azido-bridged cobalt(II) coordination polymers with nicotinate co-ligand: synthesis, structures and magnetic properties

By utilizing nicotinic acid as a co-ligand, two new azido-bridged cobalt(II) complexes with the formulae [Co(2)(N(3))(nic)(2)Cl(H(2)O)](n) (1) and [Co(N(3))(nic)](n) (2) (nic = nicotinate) have been synthesized under solvothermal condition and structurally characterized. Complex 1 exhibits a rare three-dimensional (3D) Kagomé topology with [Co4] units as connecting nodes. Complex 2 is also a 3D structure which contains 1D Co(II)-μ-1,1-azido chains as rod-shaped SBUs. Magnetic data analysis shows that ferromagnetic coupling intra-[Co4]-cluster and antiferromagnetic interaction inter-[Co4]-cluster exists in complex 1, while complex 2 exhibits metamagnetism with a critical field of 5.5 kOe.     

Syntheses and structures of five cadmium(II) coordination polymers from 1,2-bis(1,2,4-triazol-1-yl)ethane

Five structually distinct coordination polymers [Cd(bte)₃](NO₃)_{2 n} (1), [Cd(bte)₂(H₂O)₂](NO₃)_{2 n} (2), [Cd(bte)(NO₂)₂] _n (3), [Cd(bte)₂(H₂O)₂](H₂O)₂(ClO₄)_{2 n} (4) and [Cd(bte)(NCS)₂]_n (5) (bte = 1,2-bis(1,2,4-triazol-1-yl)ethane) have been synthesized and characterized. The structures of 1, 2, 3, 4 and 5 consist of a double interpenetrating three-dimensional -poloniumn cubic network, a two-dimensional (4,4) network, a two-dimensional rhombic network, a one-dimensional double chain containing 18-membered [Cd₂(bte)₂] rings and a two-dimensional rhombic network containing eight-membered [Cd₂(SCN)₂] rings, respectively.     

Synthesis, structure, and fluorescence of the novel cadmium(II)-trimesate coordination polymers with different coordination architectures

Three novel complexes, Cd3tma2*13H2O (1), Cd3tma2*dabco*2H2O (2), and Cd3Htma3*8H2O (3) (tma = trimesate), of cadmium(II)-trimesate coordination polymers are obtained from hydrothermal reaction. 1 (C18H32O25Cd3) crystallizes in the monoclinic C2/c space group [a = 18.985(2) A, b = 7.3872(6) A, c = 20.432(2) A, = 97.1660(10), and Z = 4]. 2 (C24H22N2O14Cd3) crystallizes in the monoclinic P2(1)/c space group [a = 10.1323(2) A, b = 19.5669(5) A, c = 13.15880(10) A, = 108.9810(10), and Z = 4]. 3 (C27H28O26Cd3) belongs to the trigonal P31c space group [a = 15.7547(3) A, b = 15.7547(3) A, c = 7.93160(10) A, and Z = 2]. The Cd(II) centers in the three complexes are bridged by tma ligands in the coordination fashion of unidentate, bridging unidentate, bidentate, chelating bis-bidentate, chelating/bridging bis-bidentate, or chelating/bridging bidentate to form the T-shaped molecular bilayer motif for 1, chicken-wire-like motif for 2, and honeycomb-like porous structure for 3, respectively, in which the T-shaped molecular bilayer motif and chicken-wire-like motif are further interlinked in interdigitating or alternating fashion to construct the different coordination architectures. These three complexes exhibit strong fluorescent emission bands at 355 nm (lambda(ex) = 220 nm) for 1, 437 nm (lambda(ex) = 365 nm) for 2, and 353 nm (lambda(ex) = 218 nm) for 3 in the solid state at room temperature.