Construction of zinc–organic frameworks by flexible aliphatic dicarboxylates plus 2-(1H-imidazolyl-1-methyl)-1H-benzimidazole ligand

Three new Zn(II) complexes, [Zn(ox)(imb)] (1), [Zn₂(mal)₂(imb)₂] (2), and [Zn(suc)(imb)]·H₂O (3) (imb = 2-(1H-imidazolyl-1-methyl)-1H-benzimidazole, H₂ox = oxalic acid, H₂mal = malonic acid, H₂suc = succinic acid), have been synthesized and structurally characterized. Complex 1 is a 3-D framework with a 4-connected diamond topology with the topological notation of 6⁶. Complex 2 exhibits 2-D layers with (6,3) networks. Complex 3 displays a 3-D framework constructed through unusual 2-D → 3-D parallel interpenetration of corrugated 2-D (6,3) networks. IR spectra, PXRD patterns, thermogravimetric curves, and photoluminescence spectra are addressed.     

Synthesis,crystal structures,and fluorescence properties of (RS)-2-methylglutarato Zn(II), Cd(II) complexes

Reactions of fresh M(OH)₂ (M = Zn²⁺, Cd²⁺) precipitate and (RS)-2-methylglutaric acid (H₂MGL), 2,2′-bipyridine (bipy), or 1,10-phenanthroline (phen) in aqueous solution at 50°C afforded four new metal–organic complexes [Zn₂(bipy)₂(H₂O)₂(MGL)₂] (1), [Zn₂(phen)₂(H₂O)(MGL)₂] (2), [Cd(bipy)(H₂O)(MGL)] · 3H₂O (3), and [Cd(phen)(H₂O)(MGL)] · 2H₂O (4), which were characterized by single crystal X-ray diffraction, IR spectra, TG/DTA analysis as well as fluorescence spectra. In 1, the [Zn(bipy)(H₂O)]²⁺ moieties are linked by R- and S-2-methylglutarate anions to build up the centrosymmetric dinuclear [Zn₂(bipy)₂(H₂O)₂(MGL)₂] molecules. In 2, the 1-D ribbon-like chains [Zn₂(phen)₂(H₂O)(MGL)₂] _n can be visualized as from centrosymmetric dinuclear [Zn₂(phen)₂(H₂O)₂(MGL)₂] units sharing common aqua ligands. Both 3 and 4 exhibit 1-D chains resulting from [Cd(bipy)(H₂O)]²⁺ and [Cd(phen)(H₂O)]²⁺, respectively, bridged alternately by R- and S-2-methylglutarate anions in bis-chelating fashion. The intermolecular and interchain π···π stacking interactions form supramolecular assemblies in 1 and 1-D chains in 2–4 into 2-D layers. The hydrogen bonded lattice H₂O molecules are sandwiched between 2-D layers in 3 and 4. Fluorescence spectra of 1–4 exhibit LLCT π → π* transitions.     

Two 3-D metal-organic frameworks constructed by 2-methyl or 2-ethyl imidazole dicarboxylates

Two polymeric frameworks, [Zn₅(MIDC)₂(HMIDC)₂(phen)₅] _n (1) (H₃MIDC?=?2-methyl-1H-imidazole-4,5-dicarboxylic acid, phen?=?1,10-phenanthroline) and {[Ca₂(HEIDC)₂(H₂O)]?·?H₂O} _n (2) (H₃EIDC?=?2-ethyl-1H-imidazole-4,5-dicarboxylic acid), have been solvothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Compound 1 exhibits a 3-D structure constructed from 2-D layer motifs joined by µ ₂-HMIDC^2? or µ ₃-MIDC^3? ligands. Compound 2 also presents a 3-D framework, generated from 1-D chains linked by HEIDC^2? ligands by two different µ₅-modes. The thermal and solid-state photoluminescence properties of both the complexes have been determined.     

Syntheses and structures of copper benzene-1,4-dioxydiacetate complexes with 4,4′-bipyridine and 1,10-phenanthroline

Two new copper complexes, [Cu₂(BDOA)(4,4′-bpy)₂] ? 2H₂O (1) and [Cu(BDOA)(phen)] (2) (H₂BDOA = benzene-1,4-dioxydiacetic acid; 4,4′-bpy = 4,4′-bipyridine; phen = 1,10-phenanthroline), were synthesized and characterized by IR, elemental analysis, and single-crystal X-ray diffraction. Complex 1 exhibits a 2-D three-connected network structure with 6³ topology. Complex 2 displays a 1-D chain structure. Furthermore, the 3-D supramolecular networks of 1 and 2 are constructed via rich hydrogen bonds. Thermal stability of 1 is discussed in this article.     

Synthesis,characterization, and crystal structures of two Ag (I) coordination polymers based on biphenyl-2,2′,4,4′-tetracarboxylate

In this article, [Ag₈(btc)₂(2,2′-bpy)₂] _n (1) and [Ag₄(btc)(phen)₂] _n (2) (H₄btc?=?biphenyl-2,2′,4,4′-tetracarboxylic acid, 2,2′-bpy?=?2,2′-bipyridine, phen?=?1,10-phenanthroline) have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectra, thermogravimetric analyses, and single-crystal X-ray diffraction. Complex 1 shows a 3-D framework containing a 2-D bilayer network constructed from (btc)^4? with Ag (I), whereas 2 features a 2-D supramolecular bilayer network. The differences of the two complexes demonstrate that nitrogen-containing chelating ligands have a significant effect on the formation and structure of the resulting complexes. Electrochemistry properties of 1 were also studied.     

Saccharin complexes of zinc(II) with phenanthroline and 2,9-dimethyl-1,10-phenanthroline: synthesis and characterization

The saccharinato complexes [Zn(phen)₂(sac)(H₂O)]sac (1) and [Zn(sac)(dmp)(H₂O)](sac) (2), where phen = 1,10-phenanthroline, dmp = 2,9-dimethyl-1,10-phenanthroline, and sac =saccharinato ion/ligand, were synthesized by the reaction of [Zn(sac)₂(H₂O)₄] · 2H₂O with ligands and have been characterized by elemental analysis, IR, and ¹H NMR spectroscopies. Conductivity of complexes was measured in DMSO. Compound 1 is characterized by single crystal X-ray diffraction and compared with some isomorphous zinc-saccharinate complexes reported previously. Complex 1 crystallizes in the triclinic system, space group P 1 , with Z = 2, and consists of alternating slightly distorted octahedral [Zn(phen)₂(sac)(H₂O)]⁺ and noncoordinated saccharinate. The zinc bound aqua is hydrogen bonded to an oxygen of carbonyl in the saccharinate ligand and the SO₂ group in the saccharinate counter-ion from an adjacent molecule. Intermolecular and intramolecular hydrogen bonds and C–H ··· O and C–H ··· N short contacts lead to a 3-D network.     

Syntheses,crystal structures and characterization of divalent transition metal sulfonate complexes with O-phenanthroline

Two new complexes, [Zn(phen)₂(H₂O)₂]2L·H₂O (1) and [Cu(phen)(L)(H₂O)₂]L·3H₂O (2), where HL?= 4-aminobenzenesulfonic acid and phen = o-phenanthroline, have been synthesized and their crystal structures determined by X-ray diffraction. In the complexes the Cu(II) and Zn(II) atoms revealed two different coordination environments. Complex 1 consists of a cation [Zn(phen)₂(H₂O)₂]²⁺, in which Zn(II) is six-coordinated by four nitrogen atoms from two o-phenanthroline molecules and by two water molecules. Complex 2 has two crystallographically unique Cu(II) ions, where Cu(II) ion is five-coordinate with two nitrogen atoms of o-phenanthroline, two water molecules and one sulfonate oxygen atom. The electrochemical behavior and FT-IR of the two compounds have also been studied in detail.     

Three new coordination complexes based on 2-methyl-4, 5-imidazoledicarboxylic acid varying from zero- to two-dimensionality

Reaction of 2-methyl-imidazole-4,5-dicarboxylic acid (H₃MIDC) with different salts (Zn and Mn) has led to three new H _n MIDC–metal complexes varying from zero- to two-dimensional structures under hydrothermal and solvothermal conditions. The complex [Zn(H₂MIDC)₂(H₂O)₂] (1) is a 0-D complex constructed by H₂MIDC^? and Zn centers and the complex [Mn(HMIDC)(H₂O)₂]?·?H₂O (2) is a polymeric 1-D chiral chain constructed by HMIDC^2? and Mn centers connected into a 3-D supramolecular framework with a 1-D channel. The complex [Zn₃(MIDC)₂(H₂O)₂(DMF)₂]?·?0.5H₂O (3) shows a 2-D puckered structure composed of MIDC^3? and Zn. The differences of the three complexes demonstrate that reaction solvent and temperature have important effects on the structure of these complexes. Complex 3 shows strong fluorescence in the solid state at room temperature.     

Solvent-modulated zincII networks with different stacking arrangements

Two Zn^II complexes, [Zn₂(L)₂(DMF)(H₂O)₂]·DMF (1) and [Zn(L)(DEF)]·DEF (2), were synthesized by solvothermal reactions using 4,4′-(2,3,5,6-tetramethylbenzene1,4-diyl)dibenzoic acid (H₂L) and Zn(NO₃)₂·6H₂O in different solvents of DMF, ethanol, and water for 1 and N,N-diethylformamide (DEF) for 2. The L^2? with different coordination modes connect [Zn₂(COO)₂] secondary building units (SBUs) to generate a wavy 2-D (4,4) network of 1 while in 2 there are paddlewheel [Zn₂(COO)₄] SBUs which are connected by L^2? to form a planar 2-D (4,4) network. The 2-D layered structures show different stacking arrangements and are further linked by hydrogen bonding or C–H?π interactions to give 3-D architectures. The different structures and stacking arrangements of 1 and 2 result from different reaction solvents. Photoluminescence properties of the complexes were investigated.     

Syntheses and crystal structures of two supramolecular isomers of manganese(II) with 3,5-bis(isonicotinamido)benzoate

Two new supramolecular isomeric complexes [Mn(BBA)₂(H₂O)₂] _n · 4nH₂O (1) and [Mn(BBA)₂(H₂O)₂] · 4H₂O (2) were obtained by hydrothermal reactions of MnCl₂ · 4H₂O with 3,5-bis(isonicotinamido)benzoic acid (HBBA) under different ratio of NaOH/HBBA. Complex 1 is a 1-D zigzag chain in which the Mn(II) is six-coordinate with distorted octahedral geometry. The 1-D chains are further connected by hydrogen bonds to give a 3-D supramolecular framework. Complex 2 is a monomeric molecular complex, assembled through intermolecular hydrogen bonds into a 3-D supramolecular network. Reaction conditions have remarkable influence on the structures of the complexes. The thermal and non-linear optical properties of the complexes were studied.     

Metal complexes of indole-3-acetic acid: synthesis,crystal structures,and Pb2+ chemosensing by cation-exchange reaction

Two binuclear complexes [Cu₂(IA)₄(DMSO)₂]·CH₃OH (1), [Cd₂(IA)₂(phen)₂I₂] (2), and one 1-D {[Pb₂(IA)₄]·CH₃OH}_n (3) (IAH = indole-3-acetic acid, phen = 1,10-phenanthroline) have been prepared and characterized by single crystal X-ray diffraction. Both 1 and 2 are binuclear wherein the central Cu ions are bridged by IA in 1, while Cd ions are bridged by I^? in 2. Complex 3 has a 1-D chain structure based on secondary building units (SBUs) of [Pb₂(IA)₄]. The three complexes show strong fluorescence emissions, and chemosensor behaviors for metal cations are investigated in mixed DMF/H₂O (1?:?9 v/v) solvent. The results reveal that 2 shows effective sensing to Pb²⁺. The mechanism of the detection to Pb²⁺ can be attributed to cation-exchange reaction between cadmium and lead ions.     

Synthesis and characterization of Pb(II) compounds constructed from N-tosyl-L-glutamic acid

{[Pb(tsgluo)]?·?H₂O} _n (1), [Pb₂(tsgluo)₂(phen)₂] (2), and [Pb₂(tsgluo)₂(bipy)₂] (3) (H₂tsgluo?=?N-p-tolylsulfonyl-L-glutamate, phen?=?1,10-phenanthroline, bipy?=?2,2′-pyridine) have been synthesized in the absence or presence of phen or 2,2′-bipy and structurally characterized by elemental analysis, IR, and X-ray crystallography. Single-crystal X-ray analyses reveal that tsgluo exhibits two coordination modes to link lead ions. Complex 1 gives a 2-D layer structure while 2 and 3 exhibit monomolecular structures; 3 is further connected into a double-chain structure by hydrogen bonds. Phen and 2,2′-bipy are very important for the crystal structure. Fluorescence of the compounds is also discussed.     

A mesitylene-bridged bis-benzimidazolyl ligand and six metal coordination compounds

The mesitylene-bridged bis-benzimidazolyl ligand 1,3-bis(benzimidazol-1′-yl-methyl)mesitylene (L) and six metal complexes, [Cu₉L₆(OH)₇Cl₈] (1), [Co₂L₄(NO₃)(H₂O)₂](NO₃)₃ (2), [Zn₂L₂Cl₄] (3), [CdL₂(NO₃)₂]_n (4), [MnL(L_A)(CH₃OH)]_n (5), and [CoLCl₂]_n (6) (L_A = terephthalate), have been prepared and characterized. Complex 1 is a football-like cluster formed by six Ls, nine Cu(II) ions, eight chlorides, and seven hydroxides, in which the size of the football is about 13.9 × 15.4 Å. Complex 2 contains a cage-like ball formed by four Ls and two Co(II) ions, in which the external and internal sizes of the ball are about 12.2 × 14.6 Å and 6.5 × 10.7 Å, respectively. In this complex, one nitrate is fixed in the middle of the cage through two Co–O bonds. The 24-membered metallomacrocycle of 3 is formed by two Ls and two Zn(II) ions. In 4, 2-D layers with 48-membered metallomacrocycles are formed via Ls and Cd(II) ions. In 5, L and terephthalate ions (L_A) participate in coordination with Mn(II) to afford 2-D network layers. The 1-D polymeric chain of 6 is formed via L and Co(II) chloride moieties. In the crystal packing of 1–6, 2-D supramolecular layers and 3-D supramolecular frameworks are formed via intermolecular weak interactions, including hydrogen bonds, π–π interactions, and C–H?π contacts. The conformations of metal complexes from L are described. Additionally, the fluorescence emission spectra of L and 1–6 are reported.     

Syntheses,crystal structures,and luminescent properties of three metal coordination polymers based on adipic acid and 2-(pyridine-3-yl)-(1H)-benzimidazole

Three new metal coordination polymers constructed from adipic acid and 2-(pyridin-3-yl)-(1H)-benzimidazole ligands, [M(ADP)(3PBI)₂(H₂O)₂]·2H₂O (M = Ni and Co for 1 and 2, respectively) and [Cd(ADP)(3PBI)(H₂O)] (3) [ADP = adipic acid dianion; 3PBI = 2-(pyridin-3-yl)-(1H)-benzimidazole], have been synthesized by hydrothermal reactions and were characterized by X-ray single-crystal diffraction, elemental analyses, IR, powder X-ray diffraction, and thermogravimetry. Complexes 1 and 2 are isostructural. Both form a 1-D linear chain structure, which is further assembled into a 3-D supramolecular framework by π?π stacking and hydrogen bonding interactions. Complex 3 possesses a binuclear unit and displays a 2-D layer which is further extended to a 3-D supramolecular architecture via hydrogen bonding and other weak packing interactions. The luminescent properties of 3 were investigated in the solid state at room temperature.     

Multiple modulator-induced syntheses,crystal structures,and luminescent properties on hippuric acid and bovine serum albumin of Ln(III) complexes with 2,2′-oxybis(benzoic acid)

Six new coordination complexes, Ln₂(2,2′-oba)₂(phen)₂(ox)(H₂O)₂ (Ln = Eu 1, Tb 2), Ln₄(2,2′-oba)₆(phen)₂ (Ln = Eu 3, Tb 4), Eu₄(2,2′-oba)₆(phen)₂(H₂O) (5), and K[Eu(2,2′-oba)₂(phen)₂] (6) [2,2′-H₂oba = 2,2′-oxybis(benzoic acid), phen = 1,10-phenanthroline, H₂ox = oxalic acid] were synthesized by hydrothermal reactions with the same compound molar ratios but different modulatory reagents (MRs). Complexes 1–5 have different 1-D chain structures and 6 shows a mononuclear structure. These complexes form diverse 3-D supramolecular networks through hydrogen bonds. The interaction between these complexes and hippuric acid (HA) or bovine serum albumin (BSA) was investigated by fluorescence spectral analysis. Interestingly, the hippuric acid could quench the luminescence of these complexes while the fluorescence of BSA could be quenched by these complexes. Results suggested that the complexes may be potential luminescent testing reagents for HA or BSA by significant fluorescence quenching of Ln³⁺ or BSA, respectively, through a static and dynamic quenching process.     

Synthesis,structures, catalytic,and anticancer activities of some coordination compounds involving two new triazole derivatives

Five N-heterocyclic carboxylate-based coordination complexes, [Co(L¹)₂(H₂O)₂]·2H₂O (1), [Cd(L¹)₂(H₂O)₂]·2H₂O (2), [Co(L²)(H₂O)₃] (3), [Ni(L²)(H₂O)₃] (4), and [Cu₂(L²)₂(H₂O)₂] (5), have been synthesized and characterized by elemental analysis, IR spectroscopy, Powder X-ray diffraction, thermogravimetric analyses, and single-crystal X-ray crystallography, where HL¹ is 2-((5-amino-1H-1,2,4-triazol-3-yl)thio)acetic acid and H₂L² is 2-((5-amino-1-(carboxymethyl)-1H-1,2,4-triazol-3-yl)thio)acetic acid. In these complexes, the hydrogen bonds (H-bonds) play an important role in their packing structures. Complex 1 has nine H-bonds showing a 3-D sqc38 topology. Complex 2 has 17 H-bonds exhibiting a 3-D hxl network. Complexes 3 and 4 are isomorphic, both of which possess ten H-bonds to present a 3-D btc topology. Complex 5 with eight H-bonds forms a 2-D sq1 structure. In addition, complex 3 catalyzes the decolorization of methyl orange. Meanwhile, 1, 3, and 5 show certain anticancer activities to inhibit the growth of HepG2 cells.     

Zinc(ΙΙ) complexes with 5,6-dihydro-1,4-dithiin-2,3-dicarboxylic anhydrate and different N-donors: syntheses,crystal structures,and emission properties

Two new Zn^II complexes, {[Zn(L)(phen)(H₂O)]?·?H₂O}_∞ (1) and {[Zn(L)(4bpy)(H₂O)]?·?H₂O}_∞ (2) (L?=?5,6-dihydro-1,4-dithiin-2,3-dicarboxylate, phen?=?1,10-phenanthroline, and 4bpy?=?4,4′-bipyridine), have been prepared by in situ reaction of Zn(ClO₄)₂?·?6H₂O with 5,6-dihydro-1,4-dithiin-2,3-dicarboxylic anhydrate in the presence of lithium hydroxide, together with incorporating chelating phen or bridging 4bpy as co-ligands. Their structures were determined by single-crystal X-ray diffraction. Complex 1 takes a 1-D helical structure that is further assembled into a 2-D network by O–H?···?O, C–H?···?O hydrogen bonds, and weak S?···?S interactions, and then an overall 3-D supramolecular framework was formed by π?···?π stacking interactions. Complex 2 possesses a 2-D (4,4)-layered structure. The structural difference between 1 and 2 can be attributed to the different N-donor auxiliary co-ligands. Both 1 and 2 are photoluminescent materials whose emission properties are closely related to their intrinsic structure.     

Supramolecular networks constructed by cationic copper(II) complexes incorporating hybrid water–anionic polymeric assemblies

Two complexes, [Cu₂(TFSA)(2,2′-bpy)₄]?·?TFSA?·?8H₂O (1) and {[Cu(4,4′-bpy)(H₂O)₂]?·?TFSA?·?6H₂O} _n (2) (H₂TFSA?=?tetrafluorosuccinic acid, 2,2′-bpy?=?2,2′-bipyridine, and 4,4′-bpy?=?4,4′-bipyridine), have been synthesized and structurally characterized by X-ray structural analyses. Complex 1 is a binuclear molecule bridged by TFSA ligands; 2 is a 1-D chain bridged by 4,4′-bpy ligands. The asymmetric units of the two complexes are composed of cationic complexes [Cu₂(TFSA)(2,2′-bpy)₄]²⁺ (1) and [Cu(4,4′-bpy)(H₂O)₂]²⁺ (2), free TFSA anion, and independent crystallization water molecules. A unique 2-D hybrid water–TFSA anionic layer by linkage of {[(H₂O)₈(TFSA)]^2?} _n fragments consisting of 1-D T6(0)A2 water tape and TFSA anionic units by hydrogen bonds in 1 was observed. Unique 2-D hybrid water–TFSA anionic layer generated by the linkage of {[(H₂O)₆(TFSA)]^2?} _n fragments consisting of cyclic water tetramers with appended water molecules and TFSA anionic units, and 1-D metal–water tape [Cu–H₂O?···?(H₂O)₆?···?H₂O^?] _n in 2 were found. 3-D supramolecular networks of the two complexes consist of cationic complexes and water–TFSA anionic assemblies connected by hydrogen bonds.     

Supramolecular Assemblies via Hydrogen Bonding and π-π Stacking Interactions: Crystal Structures of [Co(phen)(H2O)4]L·0.5H2O and [CO2(phen)2(H2O)2L2] with H2L = Adipic Acid

Reaction of freshly-prepared CoCO₃, phenanthroline monohydrate and adipic acid (H₂L) in CH₃OH/H₂O produced a mixture of [Co(phen)(H₂O)₄]L·0.5H₂O (1) and [CO₂(phen)₂(H₂O)₂L₂] (2). Complex 1 crystallizes in the orthorhombic space group Pbcn with cell dimensions a = 23.380(2), b = 12.347(1), c = 12.821(1) Å, and D _calc = 1.390 g/cm³ for Z = 8, and complex 2 in the triclinic space group P1; with cell dimensions a = 8.203(1), b = 9.809(1), c = 11.827(1) Å, α = 70.34(1), β = 74.81(1), γ = 71.54(1)° and D _calc = 1.592 g/cm³ for Z = 1. Complex 1 consists of [Co(phen)(H₂O)₄]²⁺ complex cations, adipate anions and crystal H₂O molecules. The Co atoms are each octahedrally coordinated by one chelating phen ligand and four water molecules with d(Co-O) = 2.041-2.097 Å and d(Co-N) = 2.144, 2.160 Å. Through hydrogen bonds, the [Co(phen)(H₂O)₄]²⁺ complex cations and adipate anions are interconnected into 2D layers, whose assembly could be ascribed to weak π-π stacking interactions between interdigitating phen ligands. Complex 2 is composed of centrosymmetric dinuclear [Co₂(phen)₂(H₂O)₂L₂) molecules, in which the Co atoms are each coordinated by two N atoms of one chelating phen ligand and four O atoms of one H₂O molecule and two adipato ligands to form distorted octahedra with d(Co-O) = 2.027-2.248 Å and d(Co-N) = 2.112, 2.162 Å. The centrosymmetric molecules are assembled via intermolecular hydrogen bonds and π-π interactions into 2D layers.     

Syntheses,structures, and properties of four coordination compounds constructed from asymmetric semi-rigid V-shaped multicarboxylate ligand

Four new compounds, [Mn(HL)(phen)₂(H₂O)] (1), [Ni(HL)(phen)₂(H₂O)] (2), [Zn(HL)(4,4′-bipy)_1.5(H₂O)] _n ?·?2nH₂O (3) and [Zn₂(HL)₂(H₂O)₆] (4), have been synthesized from an asymmetric semi-rigid V-shaped multicarboxylate 4-(4-carboxy-phenoxy)-phthalic acid (H₃L) with 1,10-phenanthroline (phen), or 4,4′-bipyridine (4,4′-bipy) as auxiliary ligands. Single-crystal X-ray diffraction analysis reveals that 1, 2 and 4 have 0-D structures with 3-D supramolecular frameworks formed by intermolecular hydrogen bonds. Compound 3 shows a 1-D infinite ribbon bridged by 4,4′-bipy, which further forms a 3-D supramolecular architecture by π–π stacking interactions and hydrogen bonds. Thermal stabilities of 1–4 and luminescence properties of 3 and 4 have also been investigated.