Fluorescence Properties Of Complexes Research Articles

Assembly of anion-controlled cadmium(II) coordination polymers based on flexible bis(imidazole) derivative

Four Cd(II) metal–organic complexes, namely, [Cd(Cl)2(bbdmbm)] (1), [Cd(NO3)(N3)(bbdmbm)1.5] (2), [Cd(BBA)2(bbdmbm)(H2O)] (3), [Cd(DNBA)2(bbdmbm)] (4), (bbdmbm=1,1-(1,4-butanediyl)bis(5,6-dimethylbenzimidazole), HBBA=4-bromobenzoic acid, and HDNBA=3,5-dinitrobenzoic acid) have been obtained from hydrothermal reactions of different Cd(II) salts with the mixed ligands of bbdmbm and five anions (Cl−, NO3−, N3−, BBA and DNBA). Single crystal X-ray diffraction analyses reveal that the four complexes exhibit different structures. Complex 1 possesses a one-dimensional (1D) helical chain, which is finally extended into a two-dimensional (2D) supramolecular structure through π–π stacking interactions. Complex 2 shows a 1D ladderlike chain bridged by bbdmbm ligands with two kinds of coordination conformations. Complex 3 is a 1D coordination polymer and is ultimately extended into a 2D supramolecular network through H-bonding interactions. Complex 4 displays a dinuclear cluster, which is finally packed into a three-dimensional (3D) supramolecular framework through three kinds of π–π stacking interactions. The Cd(II) exhibits four different coordination modes in complexes 1–4, respectively. The results indicate that the anion ligands with different steric hindrance and size play important roles in the coordination modes of Cd(II) and construction of the title complexes, leading to the structural diversity. In addition, the conformations of bbdmbm ligand also show some effect on the final structures. Fluorescence properties of complexes 1–4 are reported in this paper.

A comparison of the coordination preference of Cd, Zn, Cu(II) with flexible homophthalic acid and rigid bipyridine ligands

The mild hydrothermal reaction of Cd, Zn, or Cu(II) acetate salts with the deprotonated flexible linker homophthalic acid (H 2hmph) and the rigid molecule 4,4′-bipyridine (bpy) produced the following complexes, featured structurally by the assembly of various metal carboxylate subunits cohered further by the bpy ancillary ligand: {[Cd 2(hmph) 2(bpy)(H 2O) 2]·H 2O} n ( 1) manifests cadmium carboxylate zigzag chain motifs, containing the alternation of a hmph-bridged Cd 2(hmph) 2 dimer and an edge-shared Cd 2N 4O 10 dimer, connected further by the bpy ligands to form a layered structure with a large 50-membered ring; [Zn(hmph)(bpy)] n ( 2) processes hmph-bridged Cd 2(hmph) 2 dimer motifs inter-linked further by the bpy ligands to generate mutually embedded layered structures with square (4,4) grids; and {[Cu(hmph)(bpy)]·H 2O} n ( 3) consists of copper carboxylate helix motifs, featuring hmph-bridged CuN 2O 4 octahedra cross-linked further by the bpy ligands into a twofold-interpenetrating 3D chiral framework with a homochiral topology of a quartz dual net. This well-defined synthetic system was proposed to highlight the fact that organic linkers display markedly different coordination preferences at specific metal ions. In addition, the fluorescence properties of complexes 1 and 2 were rationalized in terms of the local ligand environments in the crystal structures, and magnetic properties of complex 3 are also given.

Three new two-dimensional metal-organic coordination polymers derived from bis(pyridinecarboxamide)-1,4-benzene ligands and 1,3-benzenedicarboxylate: Syntheses and electrochemical property

Three new metal-organic coordination polymers, [Co( 3- bpcb)(1,3-BDC)]·H 2O ( 1), [Co( 4- bpcb)(1,3-BDC)]·2H 2O ( 2) and [Cu( 4- bpcb)(1,3-BDC)] 2·0.5( 4- bpcb) ( 3), have been hydrothermally synthesized using N, N′-bis(3-pyridinecarboxamide)-1,4-benzene ( 3- bpcb) or N, N′-bis(4-pyridinecarboxamide)-1,4-benzene ( 4- bpcb) and 1,3-benzenedicarboxylate (1,3-H 2BDC) mixed ligands and characterized by elemental analyses, IR, TG, XRPD and single-crystal X-ray diffraction. Complexes 1– 2 exhibit the similar two-dimensional (2D) network with different undulation degrees and dimensions, owing to different N positions from the 3- bpcb and 4- bpcb ligands. 1,3-BDC ligand in complexes 1 and 2 shows two coordination modes. The adjacent 2D layers for 1– 2 are further linked by hydrogen bonding interactions to form a three-dimensional (3D) supramolecular network. Complex 3 possesses infinite 3-fold interpenetrating 2D network composed of three kinds of Cu- 4- bpcb one-dimensional (1D) chains and 1,3-BDC ligands, in which 1,3-BDC only shows one coordination mode. The 2D network is further extended into 3D supramolecular framework by hydrogen bonding interactions. The non-coordinated 4- bpcb ligands existing in the 2D network connect with adjacent 2D layers through the hydrogen bonding interactions. In addition, the electrochemical behaviors and the fluorescence property of complexes 1– 3 have been reported.

Hydrothermal syntheses, structures and luminescent properties of Zn(ii) coordination polymers assembled with benzene-1,2,3-tricarboxylic acid involving in situ ligand reactions

Five Zn(II) coordination polymers, [Zn(1,2,3-Hbtc)(1,4-bix)]·0.5(1,4-bix)·H2O (1), [Zn(mocip)(1,4-bix)] (2), [Zn3(1,2,3-btc)2(4,4′-bpy)2(H2O)2]2·7H2O (3), [Zn3(1,2,3-btc)2(bbi)3]2·3H2O (4) and [Zn(dmcaip)(1,3-bix)]·DMF (5), were prepared by hydro(solvo)thermal reactions of ZnO with 1,2,3-H3btc (1,2,3-H3btc = 1,2,3-benzenetricarboxylic acid) in the presence of different N-donor ligands (1,4-bix = 1,4-bis(imidazol-1-ylmethyl)benzene, 4,4′-bpy = 4,4′- bipyridine, bbi = 1,1′-(1,4-butanediyl)bis(imidazole), 1,3-bix = 1,3-bis(imidazol-1-ylmethyl)benzene, H2mocip = 2-(methoxycabonyl)isophthalic acid and H2dmcaip = 2-(dimethylcarbamoyl)isophthalic acid). Their crystal structures were determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses and IR spectra. Complex 1 has a one-dimensional (1D) infinite tubular structure, whereas 2 exhibits two-dimensional (2D) supramolecular networks assembled from 1D chains and 1,4-bix. The three-dimensional (3D) framework of 3 can be described as a trinodal 4-connected (42·64)2(65·8)(42·64)2 topology, which consists of 2D [Zn3(1,2,3-btc)2] layers and 4,4′-bpy pillars. Complex 4 features a 5-nodal (3,4)-connected 3D coordination net with a (6·74·8)2(62·72·82)(6·72)2 topology. Complex 5 has a rare 1D double meso-helical supramolecular structure. Interestingly, in the complexes 2 and 5, the starting 1,2,3-H3btc reagents are converted into new ligands (mocip2− in 2 and dmcaip2− in 5) under solvothermal conditions via in situ ligand reactions. Moreover, thermal stabilities, X-ray powder diffraction and the fluorescent properties of complexes 1–5 have been investigated.

Ancillary ligand-mediated syntheses and fluorescence properties of zinc(ii) complexes based on flexible benzene dicarboxylic acid

This work presents a well-defined synthetic system exemplifying the effect of N-donor ancillary ligands on the formation of complex architectures in a zinc(II)-H2hmph-H2O system by the mild hydrothermal route (H2hmph = homophthalic acid). The single-crystal X-ray diffractions reveal that structure variation of isolated three complexes spans the range of dimensionalities from 2D lamella [Zn(hmph)(bpe)]n (1), 2D thick-layer [Zn(hmph)(bpp)]n (2) to 3D microporous framework {[Zn2(hmph)(trz)2]·H2O}n (3), showing the marked sensitivity of the structures to the flexibility of varied N-donor ancillary ligands (bpe = 1,2-di(4-pyridyl)ethylene, bpp = 1,3-di(4-pyridyl)propane, and Htrz = 1,2,4-triazole). The structures of three complexes can be considered as the assembly of various chain-like structure motifs. The 2D lamella structure of 1 features hmph-bridged binuclear zinc(II) chains joined by less flexible trans-bpe ligands, whereas the 2D thick-layer of 2 manifests hmph-bridged mononuclear zinc(II) chains cross-linked further by flexible bpp legands along two different directions. The alternate opposite chiral helixes, featuring rigid trz-bridged mononuclear zinc(II), and additional binuclear zinc(II) units are cohered together by hmph linkers yielding a 3D microporous coordination network of 3 with new framework topology. It is shown that the structures, packing densities, and thermal stabilities of all these complexes are markedly sensitive to the molecule size, conformation, and flexibility of varied N-donor ancillary ligands. Furthermore, fluorescence properties of complexes 1–3 are also investigated.

Synthesis, Characterization and Fluorescent Property of Two Mixed Ligand Coordination Polymers Constructed from 4-Cyclohexene-1,2-dicarboxylate and Nitrogen-Containing Ligands

Two new coordination polymers [Cd(1,2′-cy)(btx)0.5H2O]n 1 and {[Ni(1,2-cy)(2,2′-bipy)(H2O)2]·3H2O}n 2 (1,2′-cy=4-cyclohexene-1,2-dicarboxylate, btx=1,4-bis(triazol-1-ylmethyl)benzene, 2,2′-bipy=2,2′-bipyridine) had been synthesized. Their structures were characterized by elemental analysis, IR, TG and X-ray single-crystal diffraction analysis. Crystal data for complex 1: Triclinic, space group P-1, a = 6.4303(13) A, b = 10.399(2) A, c = 11.713(2), α = 83.04(3)°, β = 81.87(3)°, γ = 83.84(3)°, and Z = 2. For complex 2: Orthorhombic, space group Pbcn, a = 15.613(3) A, b = 13.970(3) A, c = 21.290(4) A, and Z = 4. Complex 1 exhibits an interesting two-dimensional wavelike covalent layer structure. When Ni salt was replaced by Cd salt, and reacts with 1,2′-cy and 2,2′-bipy, one-dimensional chain-like complex 2 was obtained. Furthermore, the fluorescent property of complex 1 was reported. Two new coordination polymers [Cd(1,2′-cy)(btx)0.5H2O]n 1 and {[Ni(1,2-cy)(2,2′-bipy)(H2O)2]·3H2O}n 2 (1,2′-cy=4-cyclohexene-1,2-dicarboxylate, btx=1,4-bis(triazol-1-ylmethyl)benzene, 2,2′-bipy=2,2′-bipyridine) had been synthesized. Their structures were characterized by elemental analysis, IR, TG and X-ray single-crystal diffraction analysis. Crystal data for complex 1: Triclinic, space group P-1, a = 6.4303(13) A, b = 10.399(2) A, c = 11.713(2), α = 83.04(3)°, β = 81.87(3)°, γ = 83.84(3)°, and Z = 2. For complex 2: Orthorhombic, space group Pbcn, a = 15.613(3) A, b = 13.970(3) A, c = 21.290(4) A, and Z = 4. Complex 1 exhibits an interesting two-dimensional wavelike covalent layer structure. When Ni salt was replaced by Cd salt, and reacts with 1,2′-cy and 2,2′-bipy, one-dimensional chain-like complex 2 was obtained. Furthermore, the fluorescent property of complex 1 was reported.

Syntheses, structural characterizations and properties of 12-MC-4 organotin(IV) metallacrowns: [12-MC RSn(IV)N(shi)-4] and [12-MC RSn(IV)N(Clshi)-4] (R = Et, Bu, Ph; H 3shi = salicylhydroxamic acid; H 3Clshi = 5-chlorosalicylhydroxamic acid)

Five 12-MC-4 organotin(IV) metallacrowns(MCs) with the types of [12-MC RSn(IV)N(shi)-4] (R = Et ( 1), Bu ( 2), Ph ( 3); H 3Shi = salicylhydroxamic acid) and [12-MC RSn(IV)N(Clshi)-4] (R = Et ( 4), Bu ( 5), H 3Clshi = 5-chlorosalicylhydroxamic acid) have been synthesized and characterized by elemental analyses, IR and TGA. X-ray single-crystal diffraction analyses were also carried out and showed that all complexes 1– 5 contain a neutral 12-membered metallacrown ring which is formed by the succession of four repeating units of –[Sn–N–O]–, indicating the substituents on the tin(IV) atom are uninfluential in coordination of organotin(IV) centers with hydroxamic acid. Fluorescence properties of complexes 1– 5 have been investigated, where complex 3 displays strong fluorescence emissions in the blue region. In addition, antitumor activities of complexes 4 and 5 have also been tested, and both the complexes exhibit weak activity towards human hepatocellular carcinoma cell line (Bel-7402) and Hela cell line.

Coordination Behavior of 5,6-Substituted 1,10-Phenanthroline Derivatives and Structural Diversities by Coligands in the Construction of Lead(II) Complexes

Eight new Pb(II) metal−organic coordination polymers, {[Pb(3-PDIP)2(1,4-bdc)]·4H2O}n (1), [Pb(3-PDIP)2(bpea)]n (2), [Pb(HOIP)(pyc)2]2 (3), [Pb(HOIP)(1,3-bdc)]n (4), {[Pb(4-PDIP)(glu)]·H2O}n (5), {[Pb(4-PDIP)(1,4-bdc)]·2H2O}n (6), [Pb(4-PDIP)(1,3-bdc)]n (7), and [Pb(4-PDIP)(4,4′-bpdc)]n (8) (3-PDIP = 2-(3-pyridine) imidazo[4,5-f]1,10-phenanthroline, HOIP = 2-(4-hydroxylbenzene) imidazo[4,5-f]1,10-phenanthroline, 4-PDIP = 2-(4-pyridine) imidazo[4,5-f]1,10-phenanthroline, 1,4-H2bdc = benzene-1,4-dicarboxylic acid, H2bpea = biphenylethene-4,4′-dicarboxylic acid, Hpyc = pyridyl-2-carboxylic acid, 1,3-H2bdc = benzene-1,3-dicarboxylic acid, H2glu = glutaric acid, 4,4′-H2bpdc = biphenyl-4,4′-dicarboxylic acid), have been hydrothermally synthesized and structurally characterized. Complexes 1, 2, 4, and 6 possess one-dimensional (1D) chain structures. 3 is a mononuclear structure, and two separated molecules are connected by noncovalent interactions to generate an interesting double layer. 5 and 7 feature two-dimensional networks with (4,4) topology. Finally, complexes 1−7 are extended into three-dimensional (3D) supramolecular frameworks. 8 shows a 2-fold interpenetrating 3D framework with a rare self-penetrated topology. Three 5,6-substituted 1,10-phenanthroline derivatives exhibit two types of coordination modes and play important roles in the formation of supramolecular frameworks. The diverse structures of eight complexes may result from the different coordination behaviors of 1,10-phenanthroline derivatives, the coordination geometry of Pb(II) ion, and the coligands. Moreover, the fluorescence properties of complexes 5−8 have been investigated.

One‐ and Two‐Dimensional PbII Complexes Constructed from N‐Donor Chelating Ligands with Extended π‐System and Organic Dicarboxylates

AbstractTwo new coordination polymers [Pb(TIP)(1,3‐bdc)]n (1) and [Pb(Dpq)(fum)]n (2) (TIP = 2‐(2‐thienyl)imidazo[4,5‐f]1,10‐phenanthroline, Dpq = dipyrido[3,2‐d:2′,3′‐f]quinoxaline, 1,3‐H2bdc = benzene‐1,3‐dicarboxylic acid, fum = fumaric acid) were synthesized by hydrothermal reactions and were characterized by elemental analyses, IR spectroscopy and single‐crystal X‐ray diffraction. Complex 1 is a one‐dimensional (1D) chain, which is bridged by 1,3‐bdc ligands. This is further extended into a three‐dimensional (3D) supramolecular structure by hydrogen bonding interactions. Compound 2 exhibits a two‐dimensional (2D) network structure, which is further stacked by π–π interactions to form a 3D supramolecular framework. The most important feature of these two complexes is that the N‐donor ligands with an extended π‐system play a crucial role in the formation and stabilization of the final supramolecular frameworks. Moreover, the fluorescence property of complex 1 was also investigated in the solid state at room temperature.

A series of Zn(ii) coordination complexes derived from isomeric phenylenediacetic acid and dipyridyl ligands: syntheses, crystal structures, and characterizations

A series of new metal–organic frameworks (MOFs), [Zn(1,2-pda)(bipy)(H2O)2]n (1), [Zn(1,3-pda) (bipy)(H2O)]n·nH2O (2), [Zn(1,4-pda)(bipy)]n·nCH3OH (3), [Zn(1,2-pda)(dpe)]n·3nH2O (4), and [Zn(1,3-pda)(bpa)]n·2nH2O (5) [H2pda = phenylenediacetic acid, bipy = 4,4′-bipyridine, dpe = 1,2-di(4-pyridyl)ethylene, bpa = 1,2-bis(4-pyridyl)ethane] have been synthesized and structurally characterized. The structure determination reveals that complex 1 is a 2D layered network and exhibits a typical (4,4) topological net, which further assembles into a 3D two-fold interpenetrated pcu topology when hydrogen bonding interactions are considered. Complex 2 shows a 2D (5,2)-connected topological network via hydrogen bonding interactions based on the 1D double-chains. For complex 3, when the 1,4-pda ligands act as a three-connected node, the 2D double-layered structure displays a unique (5,3)-connected topology with a Schlafli symbol (42,67,8)(42,6). Complex 4 features a rare 3D three-fold interpenetrated diamondoid framework (dia, 66 topology) with (2.2.1) Hopf links and (6.3.3) Torus links, and the helical water chains are encased in the 1D neighboring channels. Complex 5 is a 2D corrugated net with a Schlafli symbol (44,62), and the puckered nature of the layers assembles them to interpenetrate in an unusual 2D → 3D parallel fashion. Particularly, a discrete tetramer water cluster, (H2O)4, is located in the crystal lattice of 5. The structural differences demonstrate that the backbones of the phenylenediacetic acids are a key point to form the final metal–ligand coordination polymers. Moreover, the fluorescent properties of complexes 1–5 were studied in the solid state at room temperature.

A series of metal–organic coordination polymers assembled with disulfide ligand involving in situ cleavage of S–S under co-ligand intervention

A series of new metal–organic coordination complexes, [Zn(cpds)(H2O)2]n (1), {[Zn(cpds)(4,4′-bipy)]·6H2O}n (2), {[Zn(cpds)(bpe)]2·0.5(bpe)·4H2O}n (3), [Cu(cpds)(2,2′-bipy)(CH3OH)]2·2H2O (4), {[Cu(cpds)(4,4′-bipy)(H2O)2]·2.24H2O}n (5), {[Cu(6-sinic)(4,4′-bipy)0.5]·CH3OH·H2O}n (6), [Cd2(6-mna)2(phen)]n (7), and {[Cd(cpds)(bpe)]·2.2H2O}n (8) were prepared by self-assembly of disulfide derivative of the nicotinate, 6,6′-dithiodinicotinic acid (H2cpds) with transition metal ions in the absence of different N-donor ligands (4,4′-bipy = 4,4′-bipyridine, 2,2′-bipy= 2,2′-bipyridine, phen = 1,10-phenanthroline, bpe = 1,2-bis(4-pyridyl)ethene, 6-sinic = 6-sulfinto-nicotinate, 6-mna = 6-mercaptonicotinic acid). X-Ray structure analyses of 1–8 reveal their structure ranging from the discrete unit (0D) (4), one-dimensional (1D) (1, 5), two-dimensional (2D) (7), non-interpenetrating 3D porous coordination polymers (6, 8), 2-fold interpenetrated structure (2) to a 5-fold interpenetrating framework (3), which mainly due to the differences in the bridging modes of cpds2− and the effect of the secondary ligands. Interestingly, in the complexes 6 and 7, the starting H2cpds reagent is converted into new ligands (6-sinic in 6 and 6-mna in 7) under solvothermal condition viain situ cleavage of S–S bond. In addition, thermogravimetric analyses, X-ray powder diffractions and the fluorescent properties of complexes 1, 2, 3, 7, 8 have been investigated.

Crystal structures, luminescent and thermal properties of a new series of lanthanide complexes with 4-ethylbenzoic acid

A series of lanthanide complexes with the 4-ethylbenzoic acid ligand (4-eba), [Ln(4-eba)3(phen)]2 (Ln = Nd (1), Sm (2), Eu (3), Tb (4), Dy (5) and Ho (6); phen = 1,10-phenanthroline), have been synthesized and structurally characterized by single-crystal X-ray diffraction. In the isostructural complexes 1–4, two Ln3+ ions are connected together by four bridging 4-eba ligands, with two of them in a bidentate-bridging mode and the other two in a bidentate chelating-bridging mode, and each Ln3+ is also chelated by one 4-eba group and one phen ligand, giving a coordination number of nine. In complex 5, however, two eight-coordinated Dy3+ ions are held together only by two bidentate-bridging 4-eba ligands, and another two 4-eba ligands coordinate to one Dy3+ ion in a chelating mode. In complex 6, each Ho3+ ion is eight-coordinated to four bidentate-bridging 4-eba ligands, one chelating 4-eba group and one chelating phen ligand. Thermal analysis of the six complexes is discussed by TG-DTG and IR techniques. The activation energy E values of the first decomposition stage for complexes 1–6 are calculated by integral isoconversional non-linear (NL-INT) and Ozawa iteration methods, respectively. The fluorescent properties of complexes 3 and 4 are also studied.

Metal–organic coordination architectures of bis(1,2,4-triazole) ligands bearing different spacers: syntheses, structures and luminescent properties

In our continuous efforts to explore the effects of metal ions, ligands and counter anions on the structures and properties of metal–organic complexes, six transitional metal complexes with two structurally related ligands, 1,4-bis(1,2,4-triazol-1-ylmethyl)naphthalene (L1) and 4,4′-bis(1,2,4-triazol-1-ylmethyl)biphenyl (L2), [Cd(L1)2(NO3)2(H2O)]∞ (1), [Hg(L1)0.5(Br)2] (2), {[Mn(L1)2Cl2](H2O)8}∞ (3), {[Cu(L1)2Cl2](H2O)8}∞ (4), {[Cd(L2)2(CH3OH)2(NO3)2](H2O)}∞ (5) and [Cd(L2)3(CH3OH)2(ClO4)2(CHCl3)]∞ (6), were synthesized and structurally characterized. 1 has an infinite two-dimensional (2D) network structure and the 2D network further assembled into a 3D interpenetrating structure, 2 is a dinuclear structural molecule, 3 and 4 are neutral molecules with 1D chain structures and the same packing modes, and 5 and 6 have a similar structure, consisting of a 1D neutral coordination chain, but the coordination geometry around the CdII ion in 6 is different from that in 5. The results indicated that the structural differences among them are attributable to the difference of metal ions, counter-anions and ligands frameworks. All the complexes are air stable at room temperature. L1 and L2 adopt trans–gauche as well as gauche–gauche conformation with the shortest N⋯N distance between the two donors in all complexes. Furthermore, the fluorescent properties of complexes 1, 5, 6 and all ligands have been investigated and discussed.

Synthesis, characterization and property study of new coordination polymers constructed from flexible dicarboxylates and bidentate nitrogen mixed ligands

Five new coordination polymers, [Cd(1,2′-cy) 0.5(bix)H 2O] n ( 1), [Cd 2(1,2′-cy) 2(1,10′-phen) 2(H 2O) 2] ( 2), {[Co(1,2-cy)(2,2′-bipy)(H 2O) 2]·2H 2O} n ( 3) {[Cd(succ)(1,10′-phen)H 2O]·H 2O} n ( 4), and {[Cd(succ)(2,2′-bipy)H 2O]·2H 2O} n ( 5) (1,2-cy = 4-cyclohexene-1,2-dicarboxylate, succ = succinic acid, bix = 1,4-bis(imidazol-1-ylmethyl)benzene, 1,10′-phen = 1,10-phenanthroline, 2,2′-bipy = 2,2′-bipyridine), have been synthesized and characterized by single-crystallographic X-ray diffraction. Complex 1 shows a two-dimensional covalent layer structure. Complex 2 exhibits a two-dimensional supramolecular layer network composed from discrete fundamental units. Complex 3 exhibits a one-dimensional covalent chain-like structure, which further extends to a two-dimensional supramolecular structure with hydrogen bonding and π-π interactions respectively. Complexes 4 and 5 show three-dimensional supramolecular networks composed from one-dimensional chain-like covalent structures. Furthermore, the magnetic property of complex 3 and fluorescent properties of complexes 1, 2, 4 and 5 have also been studied.

Synthesis, characterization and properties of series coordination polymers constructed from a biphenyl dicarboxylate and nitrogen-containing mixed ligands

A series of coordination polymers have been prepared by the combination of flexible ligand 1,1′-biphenyl-2,2′-dicarboxylic acid (H 2dpa) and different types of nitrogen-containing ligands, with various metal ions such as Co(II), Zn(II) and Cd(II). The single-crystal structure analyses reveal that the above complexes possess different structure features with the introduction of different nitrogen-containing ligands. When auxiliary linear ligand 4,4′-bipyridine (4,4′-bpy) is introduced, two-dimensional layered complex, [Co 2(dpa) 2(4,4′-bpy) 2(H 2O)] n ( 1) is formed. Whereas if chelating ligand, 1,10-phenanthroline (1,10′-phen) and 2,2′-bipyridine (2,2′-bpy) are introduced, one-dimensional complex [Zn(dpa)(1,10′-phen)] n ( 2) and discrete complexes [Co 2(dpa) 2(2,2′-bpy) 2(H 2O) 2] ( 3), [Co 3(dpa) 3(1,10′-phen) 6(H 2O) 2] ( 4), [Cd(dpa)(1,10′-phen) 2][(H 2dpa) 2(H 2O) 2] ( 5) are synthesized. To our interest, 1 and 2 crystallize in homochiral spacegroup. Furthermore, the magnetic property of complex 1 and the fluorescent properties of complexes 2 and 5 are studied.

Fluorescence properties of novel rare earth complexes using carboxyl-containing polyaryletherketones as macromolecular ligands

The fluorescence properties of a series of rare earth (Re 3+ = Eu 3+, Tb 3+) polymeric complexes (PEK-Re 3+-HLs) using three high- T g novel carboxyl-containing polyaryletherketones (PEK) as macromolecular ligands and small molecules (HL) such as 1,10-phenanthroline (Phen), dibenzoylmethane (DBM) and 8-hydroxyquinoline (HQ) as co-ligands were investigated by means of fluorescence excitation and emission spectroscopy as well as fluorescence lifetime measurement methods. Among them, PEK-1-Re 3+-Phens, in which the Re 3+ ions were coordinated simultaneously with Phen and PEK-1 containing both carboxyl and bulky isopropyl groups on the polymer backbone, exhibited strong fluorescence intensities, long lifetimes, and good film-formation properties. The smooth films of PEK-1-Eu 3+-Phen and PEK-1-Tb 3+-Phen, cast from their DMF solutions, could emit bright red and green light under the UV lamp of 365 nm, respectively, which characteristics are of great significance for their potential applications in the large area display material fields. The excellent fluorescence properties of complexes in this study were attributed to the synergistic effects of PEK-1 ligand and Phen co-ligand. Especially, the rigid twisted structure and the bulky isopropyl substituents on PEK-1 backbone forced the coordinated rare earth ion moieties apart, and thus the probability of non-radiative decay rate of Re 3+ ions at the excited levels were decreased to a large extent.

Assembly of novel phenanthroline-based cobalt(II) coordination polymers by selecting dicarboxylate ligands with different spacer length: From 1-D chain to 3-D interpenetrated framework

Abstract Three novel CoII coordination polymers [Co(Dpq)2(1,4-NDC)0.5] · (1,4-HNDC) (1), [Co(Dpq)(2,6-NDC)] (2), and [Co2(Dpq)2(BPEA)4(H2O)] · H2O (3) have been obtained from hydrothermal reaction of cobalt nitrate with the mixed ligands dipyrido[3,2-d:2′,3′-f]quinoxaline (Dpq) and three dicarboxylate ligands with different spacer length [1,4-naphthalene-dicarboxylic acid (1,4-H2NDC), 2,6-naphthalene-dicarboxylic acid (2,6-H2NDC) and biphenylethene-4,4′-dicarboxylic acid (BPEA)]. All these complexes are fully structurally characterized by elemental analysis, IR, and single-crystal X-ray diffraction analysis. Single-crystal X-ray analysis reveal that complex 1 is infinite one-dimensional (1-D) chains bridged by 1,4-NDC ligands, which are extended into a two-dimensional (2-D) supramolecular network by π–π interactions between the Dpq molecules. Complex 2 is a distorted three-dimensional (3-D) PtS network constructed from infinite Co–O–C rod units. Complex 3 has a 5-fold interpenetrated 3-D structure with diamondoid topology based on dinuclear [Co2(CO2)2(μ2-OH2)N4O2] units and BPEA molecules. The different structures of complexes 1–3 illustrate the influence of the length of dicarboxylate ligands on the self-assembly of polymeric coordination architectures. In addition, the thermal properties of complexes 1–3 and fluorescent properties of complexes 2 and 3 have been investigated in the solid state.

Assembly of Supramolecular Networks with the Inclusion of Water Chains, Cyclic Hepta and Octa Water Clusters

AbstractThree new supramolecular compounds were synthesized and characterized with the formula of [Zn4(picO)4(phen)4]·11.25H2O (1), [Zn4(picO)4(2,2′‐bpy)4(H2O)4]·12H2O (2), and [Zn3(picO)3(bpe)5(H2O)3]n·8.5nH2O (3) (H2picO = 6‐hydroxypicolinic acid; phen = 1,10‐phenanthroline; 2,2′‐bpy = 2,2′‐bipyridine; bpe = 1,2‐bis(4‐pyridyl)ethane). For complexes 1 and 2, picO ligands adopt tridentate, tetradentate and bidentate coordination modes to link zinc(II) ions into dimers, which are extended into 3D supramolecular structures through hydrogen bonds. Water chains with cyclic page‐like octamer and boat‐like heptamer water clusters are included, respectively. Complex 3 is of a 2D brick‐wall structure. Triple interpenetration occurs, and there are still cyclic chair‐like octamer water clusters in the channels. The fluorescent properties of complexes 1‐3 have also been investigated.

Synthesis, characterization and fluorescent properties of lanthanide complexes with two aryl amide ligands

Two aryl amide ligands, N-(p-tolyl)-2-(quinolin-8-yloxy)acetamide (L1 ) and N-(4-chlorophenyl)-2-(quinolin-8-yloxy)acetamide (L2 ), were synthesized. With these ligands, two series of lanthanide(III) complexes were prepared, Ln(L n )2(NO3)3 (n = 1, 2; Ln = La, Sm, Eu, Gd, Dy), and characterized by the elemental analyses, molar conductivity, 1H NMR spectra, IR spectra and TG-DTA. The fluorescence properties of the complexes and the triplet state energies of the ligands were studied in detail. In addition, the quantum yields of both Eu(III) complexes and Eu(L0)2(NO3)3 [where L0 is N-(phenyl)-2-(quinolin-8-yloxy)acetamide] 1 were calculated. The results indicate that among the lowest triplet energies (T) of the three ligands, that of L2 is most suitable to the resonance level (5D1) of Eu(III) ion. Furthermore, Eu(L2)2(NO3)3 has the highest fluorescence intensity and quantum yield of the three Eu(III) complexes.

Metal Coordination Architectures of 2,3‐Bis(triazol‐1‐ylmethyl)quinoxaline: Effect of Metal Ion and Counterion on Complex Structures

AbstractA series of complexes, [ZnLCl2]2 (1), [ZnL2(NO3)2]∞ (2), [MnL2(NO3)2]∞ (3), {[ZnL2(H2O)2](ClO4)2(CH3COCH3)2}∞ (4), {[MnL2(H2O)2](ClO4)2(CH3COCH3)2}∞ (5), {[CdL2(H2O)2]‐(ClO4)2(H2O)6}∞ (6), and {[AgL](ClO4)(H2O)1.5}∞ (7), based on the flexible ligand 2,3‐bis(triazol‐1‐ylmethyl)quinoxaline (L) were synthesized and characterized by elemental analyses, IR spectroscopy, thermogravimetric analyses, and single‐crystal X‐ray diffraction. Complex 1 is a dinuclear macrocyclic molecular, which is further linked into a 1D supramolecular chain by intermolecular C–H···Cl weak interactions. The metal centers in 2 and 3 coordinate two NO3– anions, and the flexible ligand bridges M(NO3)2 [M = ZnII or MnII] units to form 1D chain structures. Complexes 4, 5, and 6 show a 2D network structure with (4,4) topology. As expected, complex 7 has a 1D strand chain structure that is different than other MII complexes (4, 5, and 6) with the same ligand. These chains are further extended into a 2D supramolecular network by O···Ag···O weak interactions. In all these complexes, the ligand bridges in a similar mode; however, the complexes have different structures ranging from a dinuclear structure to a 2D network mainly due to the differences in the coordination geometries of the metal centers and counterions. These results reveal that the coordination geometry of metal ions and the coordinating abilities of the counterions play important roles in defining the overall structure of metal–organic frameworks. In addition, the fluorescent properties of complexes 1, 2, 4, 6, 7, and ligand L and the EPR spectra of complex 5 were also investigated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)