Flexible Bis Research Articles

Syntheses, Structures, and Properties of Two New Co(II) Coordination Frameworks Based on R-Isophthalate (R = –CH3 or –OCH3) and Two Flexible Bis(imidazol) Coligands

Two new coordination polymers, {[Co(CH3-ip)(1,4-bib)]· 2H2O} n (1) and {[Co(CH3O-ip)(1,6-bih)]} n (2) (CH3-H2ip = 5-methylisophthalic acid, CH3O-H2ip = 5-methoxyisophthalic acid, 1,4-bib = 1, 4-bis(imidazol-1-yl)butane, 1,6-bih = 1,6-bis(imidazol-1-yl)hexane), have been obtained under hydrothermal conditions. Complexes 1 and 2 were determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis and IR spectroscopy. Complex 1 shows a two-dimensional (2D) corrugated layer containing left and right-handed helical chains. Compound 2 exhibits a 2-fold parallel interpenetrated 2D → 2D net. Furthermore, thermogravimetric properties of 1 and 2 were also investigated. Supplemental materials are available for this article. Go to the publisher's online edition of Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry to view the supplemental file.

Tuning Different Kinds of Entangled Networks Formed by Isomers of Bis(1,2,4-triazol-1-ylmethyl)benzene and a Flexible Tetracarboxylate Ligand

In order to tune the Zn(II) coordination polymer architectures, three position isomers, 1,4- (pbtmb), 1,3- (mbtmb), and 1,2-bis(1,2,4-triazol-1-ylmethyl)benzene (obtmb), and flexible tetracarboxylate ligand, 5,5′-(1,4-phenylenebis(methylene))bis(oxy)diisophthalic acid (H4L1), were used to assemble compounds with different kinds of entangled networks, namely, {[Zn2(L1)(pbtmb)2]·4H2O}n (1), {[Zn2(L1)(mbtmb)2]·4H2O}n (2), and [Zn2(L1)(obtmb)2]n (3). Flexible bis(triazole) ligands present diverse conformations in these compounds. Compound 1 shows a 4-fold interpenetrating three-dimensional architecture with 4-connected mog (moganite) topology. Compound 2 displays a 2D + 2D → 3D polycatenation network simplified as new 4-connected topology with the Schlafli notation of {4,64;8}2{42,64}. Compound 3 is a 2D polythreading structure, in which two layed networks interpenetrate in a (2D/2D) parallel fashion. The powder X-ray diffraction, thermal stabilities, and the photoluminescence of 1–3 have also been investigated.

Preparation and crystal structure of a triple parallel interpenetrated copper coordination polymer based on a flexible bis(imidazole) ligand

A Cu(II) coordination polymer, [Cu(L)(bdc)] n (L = 1,4-bis(imidazole)butane, bdc = 1,3-benzenedicarboxylate) has been hydrothermally synthesized and characterized by elemental analysis, IR spectrum, thermogravimetric analysis, and single-crystal X-ray diffraction. The complex is a rare example of a threefold parallel interpenetrated coordination bonding network based on undulant [Cu4(μ 2-L)2(μ 2-bdc)2] parallelograms with 44-sql layer. The heterogeneous catalytic activity of the complex was tested for the degradation of Congo red azo dye in a Fenton-like process in which the degradation efficiency reached 94 % after 100 min. Kinetic analysis indicates that the degradation rate of the dye can be approximated by pseudo-first-order kinetics.

Nano-dimensional square grid, helix chain, interpenetrated double layer, and chain of ring structures in new cobalt(II) metal–organic polymers based on 4,4′-oxybis-(benzoic acid) and 1,n-bis(imidazol-l-yl-methyl)benzene (n = 2, 3, 4)

Four cobalt(II) coordination polymers, [Co2(oba)2(1,2-bix)2]n (1), [Co(oba)(1,3-bix)]n (2), {[Co4(oba)4(1,4-bix)4]·6H2O}n (3), and {[Co6(oba)6(1,4-bix)6]·2H2oba·3DMF·11H2O}n (4), where H2oba = 4,4′-oxybis(benzoic acid), DMF = N,N-Dimethyl formamide, and 1,n-bix = 1,n-bis(imidazol-l-yl-methyl)benzene (n = 2, 3, 4), have been synthesized. These compounds were structurally characterized by single-crystal X-ray crystallography, IR spectroscopy, and thermogravimetric analysis. Compound 1 exhibits a 2-D nano square grid (4,4) network, while 2 features a 2-D structure with two distinct left- and right-handed helical chains. Compound 3 possesses a doubly interpenetrated double-layered framework structure. The structure of 4 is comprised of 1-D chains of rings. The structural differences reveal that the flexible dicarboxylate and neutral bis(imidazole) are effective building blocks in constructing coordination polymers with diverse architectures.

Hydrothermal synthesis, crystal structural, and thermal properties of a 1D zinc coordination polymer based on benzoate and flexible bis(benzimidazole) ligands

A new coordination polymer, [Zn(PhCOO)2(Bbbm)]n (I), where Bbbm = 1,1′-(1,4-butanediyl)bis-1H-benzimidazole, has been synthesized under hydrothermal conditions and characterized by elemental analysis, IR, TG and X-ray single-crystal diffraction. The complex crystallizes in the monoclinic system with space group P21/n, the unit cell parameters: a = 10.815(3), b = 20.516(6), c = 12.802(4) A, β = 102.025(3)°, V = 2778.2(14) A3, Z = 4. In this structure, the Zn2+ ion is in a distorted tetrahedral geometry, one-dimensional linear chain is constructed by Bbbm ligand with bis(monodentate) coordination mode.

Construction of Two New Metal–Organic Entangled Frameworks Via Varying Flexible Bis(Imidazole)-based Auxiliary Ligands

Two new metal–organic entangled frameworks, namely [Cd(FA)0.5(bix)1.5(H2O)] n ·nNO3 (1) and [Cd(FA)(bib)(H2O)2] n (2) (FA = fumaric acid, bix = 4,4′-bis(imidazol-1-ylmethyl)benzene, bib = 1,4-bis(imidazolyl)butane), have been successfully hydrothermally synthesized through mixed ligands strategy. Single crystal X-ray diffraction analysis reveal that 1 is a 2D → 3D polycatenated framework, while 2 is a triply interpenetrated 4-connected dia topological net. Moreover, both compounds exhibit intense luminescence emission at room temperature.

Syntheses, structures and properties of three cobalt coordination polymers based on flexible bis(triazole) and 5-nitroisophthalate coligands

Three coordination polymers {[Co(bte)(NO2-1,3-bdc)(H2O)]⋅H2O}n (1), {[Co(btp)(NO2-1,3-bdc)(H2O)]⋅2H2O}n (2) and {[Co2(btb)2(NO2-1,3-bdc)2]⋅2H2O}n (3) were synthesized by the different spacer lengths and conformational flexibilities bte, btp, btb and the rigid NO2-1,3-bdc. 1 forms an independent 1D MONT and a (1D→2D) interdigitated array. In 2, two identical undulated (4,4) networks are parallel stacking to give a double-layer. In 3, the btb ligands connect the [Co2(NO2-1,3-bdc)2]n ladders to construct an unusual 3D network with point symbol 46⋅67⋅82 based on [Co2(COO)2] unit. The thermal stability and the UV–vis spectra of 1, 2 and 3 were investigated.

A series of Cu(ii) and Cd(ii) coordination polymers constructed by 3,5-dinitrosalicylic acid and flexible bis(triazole) ligands containing different spacers

A series of coordination polymers based on 3,5-dinitrosalicylic acid (H2sal) and nine flexible bis(triazole) ligands, namely, [Cu4(sal)4(L1)2(H2O)]·2H2O (1), [Cu4(sal)4(L2)2(H2O)] (2), [Cu2(sal)2(L3)(H2O)] (3), [Cu2(sal)2(L4)(H2O)] (4), [Cu5(sal)4(OH)2(L5)2(H2O)3]·H2O (5), [Cu(sal)(L6)] (6), [Cu2(sal)2(L7)] (7), [Cu(sal)(L8)]·0.5H2O (8), [Cd2(sal)2(L1)(H2O)2] (9), [Cd2(sal)2(L7)3] (10) and [Cd4(sal)4(L9)4] (11), where L1 = 1,2-bis(1,2,4-triazol-1-yl)ethane, L2 = 1,3-bis(1,2,4-triazol-1-yl)propane, L3 = 1,4-bis(1,2,4-triazol-1-yl)butane, L4 = 1,5-bis(1,2,4-triazol-1-yl)pentane, L5 = 1,5-bis(1,3,4-triazol-1-yl)pentane, L6 = 1,6-bis(1,2,4-triazol-1-yl)hexane, L7 = 1,10-bis(1,2,4-triazol-1-yl)decane, L8 = 1,4-bis((1H-1,2,4-triazol-1-yl)methyl)benzene and L9 = 1,1′-(2,2′-oxybis(ethane-2,1-diyl))bis(1H-1,2,4-triazole), have been synthesized and characterized by single crystal X-ray diffraction, elemental analyses, IR spectra, PXRD spectra and TG analysis. Compounds 1 and 4 possess one-dimensional (1D) double chains. Compounds 2, 3 and 5 show two-dimensional (2D) 44 networks. Compound 6 displays a three-dimensional (3D) uninodal eight-connected self-penetrating framework with the 42068 topology. Compound 7 reveals a 2D 2-fold interpenetrating 44-sql network. Compounds 8 and 9 display 2D undulated layers. Compound 10 shows a 1D chain. Compound 11 reveals a discrete tetranuclear cluster. The UV-vis spectra and optical energy gap of 1–11 have also been investigated in detail.

Metallomacrocycles as anion receptors: combining hydrogen bonding and ion pair based hosts formed from Ag(i) salts and flexible bis- and tris-pyrimidine ligands

Two self-assembled hosts are formed from Ag(I) salts and bis-pyrimidyl ligands and X-ray characterized. Both are able to incorporate two anions into the structure combining hydrogen bonding and electrostatic interactions.

Seven structural versatile coordination polymers based on a flexible bis(triazole) and polycarboxylate co-ligands: syntheses, structures and properties

Seven coordination polymers {[Mn(tmtz)0.5(OH-bdc)(H2O)2]·2.75H2O}n (1), [Mn(tmtz)1.5(1,3-bdc)]n (2), [Mn(tmtz)(1,4-bdc)]n (3), [Co(tmtz)(oba]n (4), {[Co4(tmtz)2(bptc)2(H2O)7]·3.5H2O}n (5), {[Ni(tmtz)1.5(1,3-bdc)]·0.5H2O}n (6), [Ni(tmtz)(oba)(H2O)]n (7) (tmtz = 1,4-bis(1,2,4-triazol-1-ylmethyl)-2,3,5,6-tetramethylbenzene, OH-bdc = 5-hydroxy-1,3-benzenedicarboxylate, 1,3-bdc = 1,3-benzenedicarboxylate, 1,4-bdc = 1,4-benzenedicarboxylate, H2oba = 4,4′-oxybis(benzoic acid), bptc = 3,3′,4,4′-benzophenonetetracarboxylate) have been synthesized and structurally characterized. 1 exhibits a 1D ladder structure and a 3D supramolecular architecture. 2 and 6 have similar 5-connected 2D networks through the 1,3-bdc ligand connecting [M(tmtz)1.5]n 1D ladders, with the point symbol (48·62). 3 has a (4,6)-connected 3D fsc network with a point symbol of (44·62)(44·610·8). 4 shows a 1D tubular-like chain. 5 exhibits a complicated (3,4,4)-connected 3D network with a point symbol of (4·10·12)2(4·83·10·12)2(82·102·122). Such a (3,4,4)-connected 3D network is unprecedented to the best of our knowledge. 7 displays a 2D (4,4) network which crystallizes in the chiral orthorhombic space group P212121. The results indicate that the central metal ions, polycarboxylate and flexible triazole co-ligands have a great effect on the formation and the structures of the coordination polymers. The thermal stability and luminescence were investigated. The crystal structures and solid-state circular dichroism (CD) spectra measurements confirmed the occurrence of the spontaneous resolution of 7 and demonstrated that the resulting crystal of 7 is a racemic mixture.

Entangled Zn(ii)/Cd(ii) coordination complexes based on a flexible bis(methylbenzimidazole) ligand and different dicarboxylates

Eight entangled coordination complexes, formulated as [M(hbmb)0.5(o-phda)]n [M = Zn (1), Cd (2)], {[M(hbmb)(p-phda)]·H2O}n [M = Zn (3), Cd (4)], [M(hbmb)0.5(oba)]n [M = Zn (5), Cd (6)], {[M(hbmb)(sdba)]m}n [M = Zn, m = 2 (7); m = 1, Cd (8)] (H2phda = phenylenediacetic acid, H2oba = 4,4′-oxybis(benzoic acid), H2sdba = 4,4′-sulfonyldibenzoic acid), have been prepared by hydrothermal reactions of the flexible ligand 1,1′-(1,6-hexane)bis-(2-methylbenzimidazole)) (hbmb) with metal ions in the presence of various dicarboxylate coligands. Isostructural complexes 1 and 2 reveal 6-connected self-penetrating three-dimensional (3D) frameworks with (44·610·8)-roa topologies. 3 and 4 display 4-fold interpenetrating 3D frameworks with 66-dia topologies. 5 and 6 exhibit 3D 2-fold interpenetrating 6-connected frameworks with (412·63)-pcu topologies. Both 7 and 8 are 3D frameworks constructed through unusual 2D → 3D parallel interpenetration of corrugated 2D (4,4) nets, of which 7 shows a 4-connected (44·62)2 topology and 8 presents a 4-connected 44·62 topology. A systematic structural comparison of four pairs of complexes shows that the frameworks can be tuned by various dicarboxylate coligands and changeable conformations of the hbmb ligand. In addition, the chemical stability, thermal stability and photoluminescent properties of complexes 1–8 have also been investigated.

A series of Zn(ii) and Cd(ii) coordination polymers based on flexible bis-[(pyridyl)-benzimidazole] ligand and different carboxylates: syntheses, structures, and photoluminescent properties

Eight new coordination polymers, namely, [Zn(m-bdc)(L)] (1), [Zn(NH2–bdc)(L)] (2), [Zn3(p-bdc)3(L)]·2H2O (3), [Zn3(btc)2(L)(H2O)]·H2O (4), [Cd(o-bdc)(L)(H2O)] (5), [Cd(m-bdc)(L)] (6), [Cd(p-bdc)(L)(H2O)] (7) and [Cd2(btda)(L)]·H2O (8) (m-H2bdc = 1,3-benzenedicarboxylic acid, NH2–H2bdc = 5-NH2–1,3-benzenedicarboxylic acid, p-H2bdc = 1,4-benzenedicarboxylic acid, H3btc = 1,3,5-benzenetricarboxylic acid, o-H2bdc = 1,2-benzenedicarboxylic acid, btda = 3,3′,4,4′-benzophenonetetracarboxylic dianhydride and L = 1,1′-(1,4-butanediyl)-bis[2-(3-pyridyl)benzimidazole]), have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction. Compounds 1 and 2 display bilayer structures. The neighboring layers of 2 are further linked by hydrogen-bonding interactions to form a 3D supramolecular architecture. Compound 3 shows a 3D 8-connected (36·410·511·6) topology. Compound 4 exhibits a 3D (3,4)-connected (5·7·8)2(42·6·72·8)2(42·52·6·7)2(72·84) net. Compound 5 reveals a layer. The layers are further connected by π–π interactions to give rise to a 3D supramolecular architecture. Compound 6 shows a 3D framework with (3,5)-connected (42·6)(4·102)2(43·6·84·102) topology. The structure of compound 7 is a 3D (3,4)-connected framework with (4·82)(4·9·10)2(42·82·92·104) topology. Compound 8 displays a 3D (3,4)-connected (4·102)2(42·82·102)(42·84)2 topology. Their photoluminescent behaviours have been investigated in detail.

Controlling interpenetration in metal–organic frameworks by tuning the conformations of flexible bis(triazole) ligands

Solvothermal syntheses afforded two new MOFs {[Zn2(L1)(btmbb)(H2O)4]·2H2O}n (1) and [Zn2(L1)(btmbb)2]n (2) [5,5′-(1,4-phenylenebis(methylene))bis(oxy)diisophthalic acid (H4L1), and 4,4′-bis((1H-1,2,4-triazol-1-yl)methyl)biphenyl (btmbb)]. Single crystal X-ray analyses reveal that compound 1 shows an example of a 2D non-interpenetrating network, while compound 2 is a 2D polythreading interpenetrating structure, in which two layered networks interpenetrate in a (2D/2D) parallel fashion. The different conformation of the flexible ligand might be the main factor resulting in these non-interpenetrated/interpenetrated structures. The powder X-ray diffraction, thermal stabilities, and the photoluminescence of 1–2 have also been investigated.

Two unusual 3D and 2D zinc coordination polymers containing 2D or 1D [Zn2(btec)]n based on flexible bis(triazole) and rigid benzenetetracarboxylate co-ligands

In order to investigate the influence of flexible bis(triazole) ligands on the motifs, two zinc coordination polymers {[Zn2(bte)(btec)(H2O)4]•2H2O}n (1) and {[Zn2(btp)2(btec)]•10H2O}n (2) were synthesized by the self-assembly reaction of 1,2,4,5-benzenetetracarboxylate (btec), 1,2-bis(1,2,4-triazol-1-yl)ethane (bte), or 1,3-bis(1,2,4-triazol-1-yl)propane (btp). In 1, the bte ligands connect the 2D [Zn2(btec)]n networks to generate an unusual (3,4)-connected 3D network. The Schläfli symbol of the 3D network is (6•102)(62104). In 2, each btp ligand links two [Zn2(btec)]n 1D belts to form a (4,4)-connected 2D network with the 1D channels ca. 8.0 × 10.0 Å2 along the a-axis. The btp ligands of each 2D network interpenetrate into two adjacent identical 2D networks to form a 3D supramolecular network in 2. The luminescences and thermal stabilities of 1 and 2 were also investigated.

1.1]Ferrocenophanes and Bis(ferrocenyl) Species with Aluminum and Gallium as Bridging Elements: Synthesis, Characterization, and Electrochemical Studies

Salt-metathesis reactions between dilithioferrocene (Li(2)fc·2/3tmeda) and intramolecularly coordinated aluminum and gallium species RECl(2) [R = 5-Me(3)Si-2-(Me(2)NCH(2))C(6)H(3); E = Al (2a), Ga (2b); and R = (2-C(5)H(4)N)Me(2)SiCH(2); E = Al (3a), Ga (3b)] gave respective [1.1]ferrocenophanes ([1.1]FCPs). Those obtained from 2a and 2b, respectively, were isolated as analytically pure compounds and fully characterized including single-crystal X-ray structure determinations [4a (Al): 43%; 4b (Ga): 47%]. Bis(ferrocenyl) compounds of the type REFc(2) [R = 5-Me(3)Si-2-(Me(2)NCH(2))C(6)H(3); E = Al (5a), Ga (5b); and R = (2-C(5)H(4)N)Me(2)SiCH(2); E = Al (6a), Ga (6b)] and R(2)SiFc(2) [R = Me (7(Me)); Et (7(Et))] were prepared, starting from respective element dichlorides and lithioferrocene (LiFc). Molecular structures of 6a, 7(Me), and 7(Et) were solved by single-crystal X-ray analyses. One of the two Fc moieties of 6a was bent toward the open coordination site of the aluminum atom. The measured dip angles α* of the two independent molecules in the asymmetric unit were 11.9(5) and 13.3(5)°, respectively. The redox behavior of [1.1]FCPs 4 and bis(ferrocenyl) species 5, 6, 7, and (Mamx)EFc(2) [Mamx = 2,4-tBu(2)-6-(Me(2)NCH(2))C(6)H(2); E = Al (8a), Ga (8b)] were investigated with cyclic voltammetry. While all gallium and silicon compounds gave meaningful and interpretable data, all aluminum compounds were problematic with the exception of 8a. Aluminum species, compared to respective gallium species, are more sensitive and, presumably, fluoride ions or residual water from the electrolyte and solvent are causing degradation. The splitting between the formal potentials for bis(ferrocenyl) species was significantly smaller (5b, 6b, and 8b: ΔE°' = 0.138-0.159 V) than that of the [1.1]FCP 4b (ΔE°' = 0.309 V). These results were explained by assuming an electrostatic interaction between the two iron centers; differences between bis(ferrocenyl) species and [1.1]FCPs are likely due to a more effective solvation of Fe-containing moieties in the more flexible bis(ferrocenyl) species.

Aromatic Polycarboxylate-Tuned Assembly of Three New 2D Copper(II) Complexes Derived from a Flexible Bis(pyridylamide) Ligand

Three new 2D copper(ii) complexes [Cu(NIPH)(L)] (1), [Cu(BDC)(L)(H2O)] (2), and [Cu(HBTC)(L)]·2H2O (3) were hydrothermally synthesized by self-assembly of aromatic polycarboxylates (H2NIPH = 5-nitroisophthalic acid, H2BDC = 1,3-benzenedicarboxylic acid, H3BTC = 1,3,5-benzenetricarboxylic acid) and the flexible bis(pyridylamide) ligand L (L = N,N′-di(3-pyridyl)succinamide), and structurally characterized by single crystal X-ray diffraction, and elemental, IR, and thermogravimetric analyses. Compound 1 is a 2D coordination polymer based on tri-flexural helix chains (left-, right-handed [Cu-L]n helix chains, and left-handed Cu-NIPH helix chain). Compound 2 exhibits a 2D wavelike polymeric layer structure constructed from a 1D [Cu-L]n sinusoidal chain and a 1D [Cu-BDC]n V-like chain. Compound 3 possesses a 2D double-layer network formed from 1D [Cu-L]n zigzag chains and 1D [Cu-HBTC]2n double chains. The fluorescent properties of the three compounds and the electrochemical behaviour of compound 2-bulk-modified carbon paste electrode were also studied.

Synthesis, Crystal Structures and Fluorescence Properties of Two One-Dimensional Cadmium(II) Coordination Polymers Containing Flexible Bis(benzimidazole) Ligands

Two one-dimensional Cd(II) coordination polymers constructed by ribbon-like molecules, {[Cd(L1)2(NO3)]·NO3}n (1) (L1 = 1,3-bis(5,6-dimethylbenzimidazol-1-yl)benzene) and [Cd(L2)2(NO3)2]n (2) (L2 = 1,3-bis(benzimidazol-1-yl)benzene) have been obtained through assembly of the two structurally similar flexible bis(benzimidazole)-based ligands and cadmium nitrate tetrahydrate. The cadmium(II) centers display different coordination environments with trigonal-bipyramidal geometry in 1, and a octahedral geometry in 2. Weak C–H···O interactions in 1 result in a two-dimensional supramolecular layer; two π–π interactions are present in 2 forming a three-dimensional supramolecular network structure. The solid state fluorescence properties of 1 and 2 were investigated.

The Role of the Coordination Modes of a Flexible Bis(pyridylamide) Ligand in the Topology of 2D Copper(II) Complexes

Two new two-dimensional copper(II) coordination polymers, [Cu(L)(BDC)]_H2O (1) and [Cu2(L)0:5(SIP)(OH)(H2O)] 2H2O (2) [L=N;N0-bis(3-pyridylamide)-1,6-hexane, H2BDC=1,3- benzenedicarboxylic acid, H3SIP=5-sulfoisophthalic acid (3,5-dicarboxybenzenesulfonic acid)], have been synthesized hydrothermally by self-assembly of the flexible bis-pyridyl-bis-amide ligand L and the aromatic polycarboxylate ligands H2BDC or H3SIP. X-Ray diffraction analysis reveals that complex 1 displays a metal-organic coordination layer with a binodal (3,5)-connected {42.67.8}{42.6} topology, in which the L ligands adopt a m2-bridging mode (via ligation of the pyridyl nitrogen atoms). Complex 2 also exhibits a layered network based on tetranuclear copper clusters [Cu4(μ3-OH)2(H2O)2(O2C-)4], L ligands and SIP anions, showing a binodal (4,8)-connected network with {414.610.84}{44.62} topology, in which the L ligands adopt a μ6-bridging coordination mode (via ligation of the pyridyl nitrogen and carbonyl oxygen atoms). Adjacent layers in 1 and 2 are further linked by hydrogen bonding interactions to form three-dimensional supramolecular frameworks. The electrochemical behavior of the two complexes in bulk-modified carbon paste electrodes has been investigated

Structure-directing role of anionic ligands in the assembly of Cd(II) coordination polymers based on SO42−/3,5-dicarboxybenzenesulfonate and flexible bis(benzimidazole) derivatives

Three new Cd(II) coordination polymers, [Cd(hbdmbm)(SO4)]n (1), {[Cd3(hbdmbm)4(5-SSPIA)2]·(H2O)2}n (2) and [Cd3(bbdmbm)4(5-SSPIA)2]n (3), based on different O-containing anionic ligands and flexible bis(benzimidazole) derivatives (hbdmbm=1,1′-(1,6-hexanediyl)bis(5,6-dimethylbenzimidazole), bbdmbm=1,1′-(1,4-butanediyl)bis(5,6-dimethylbenzimidazole), 5-SSPIA=sodium 3,5-dicarboxybenzenesulfonate), have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Structure analysis illustrates that complex 1 possesses a 2D (4, 4) network constructed from the binuclear [Cd(SO4)]2 secondary building unit (SBU) and the hbdmbm. Complex 2 shows a 2D/3D crossed 3D framework with Schläfli symbol of (63)2(65·8)(68·82)2. In 2, Cd(II) ions are connected by hbdmbm ligands to construct a 3D framework showing a topological octagon geometry, and also linked by 5-SSPIA to construct a 2D layer with polygon geometry, in which 5-SSPIA anions act as three-connected nodes. Complex 3 shows more complicated 3D framework with Schläfli symbol (4·64·8)(4·82)(42·53·63·7·8)(42·53·6)(5·6·7·82·9), which contains two kinds of SBUs built by 5-SSPIA and bbdmbm. 5-SSPIA anions act as three-connected nodes and four-connected nodes in 3. The structure-directing role of anionic ligands and the effects of conformations of N-donor ligands on the final structures are discussed. In addition, fluorescence properties of complexes 1–3 are also reported in this paper.

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.