Hydrothermal synthesis,crystal structure and characterization of a new 1-D supramolecular ladder based on a binuclear CdII complex [Cd2L4(3,5-DNBA)2](H2O) with L as a bridging ligand (L=3-(2-pyridyl)pyrazole; 3,5-DNBA=3,5-dinitrobenzoate)

A new 1-D cadmium(II) mixed ligand dimer supramolecular ladder [Cd₂ L ₄(3,5-DNBA)₂]H₂O (1), (L?=?3-(2-pyridyl)pyrazole and 3,5-DNBA?=?3,5-dinitrobenzoate) was synthesized by hydrothermal methods. X-ray structural analysis of complex 1 revealed that two cadmium(II) cores are bridged by two deprotonated pyrazole groups of L, leading to dinuclear cadmium(II) [Cd₂ L ₄(3,5-DNBA)₂]. The dimers are joined by hydrogen-bonding interactions between two different cadmium(II) dimers to form a one-dimensional ladder-like framework and stabilized by weak π–π interactions. Moreover, the fluorescence spectrum of compound 1 exhibits blue fluorescent emission in the solid state at room temperature.     

Cobalt (II) coordination polymers based on 3,5-dinitrobenzoate and flexible bis(benzimidazole) derivatives bearing different spacer lengths and substituents

Three new Co^II coordination polymers, namely [Co(DNBA)₂(pbdmbm)] (1), [Co₂(H₂O)₂(DNBA)₂(ebdmbm)₂] (2) and [Co₂(DNBA)₂(pbbm)₂] (3) have been obtained by hydrothermal reactions of Co^II with flexible bis(benzimidazole) ligands [1,1′-(1,3-propanediyl)bis(5,6-dimethylbenzimidazole) (pbdmbm), 1,1′-(1,2-ethanediyl)bis(5,6-dimethylbenzimidazole) (ebdmbm), 1,1′-(1,3-propanediyl)bis(benzimidazole) (pbbm)] plus 3,5-dinitrobenzoic acid (HDNBA). The complexes have been characterized by single crystal X-ray diffraction, elemental analyses, IR and TG. Complexes 1 and 3 exhibit one-dimensional chains composed of Co^II centers bridged by flexible bis(benzimidazole) ligands. Complex 2 is a three-dimensional NaCl-type supramolecular framework constructed from binuclear units, which are formed by two Co^II centers and two ebdmbm ligands. The spacer length and substituents on the bis(benzimidazole) ligands are crucial for the construction of these structures. The photoluminescence properties of the complexes and the cyclic voltammetry behavior of complex 1 are described.     

Novel polyoxometalate-templated, 3-D supramolecular networks based on lanthanide dimers: synthesis,structure, and fluorescent properties of [Ln2(DNBA)4(DMF)8][Mo6O19] (DNBA = 3,5-dinitrobenzoate)

The spherical Lindquist type polyoxometalate, Mo(6)O(19)(2)(-), has been used as a noncoordinating anionic template for the construction of novel three-dimensional lanthanide-aromatic monocarboxylate dimer supramolecular networks [Ln(2)(DNBA)(4)(DMF)(8)][Mo(6)O(19)] (Ln = La 1, Ce 2, and Eu 3, DNBA = 3,5-dinitrobenzoate, DMF = dimethylformamide). The title compounds are characterized by elemental analyses, IR, and single-crystal X-ray diffractions. X-ray diffraction experiments reveal that two Ln(III) ions are bridged by four 3,5-dinitrobenzoate anions as asymmetrically bridging ligands, leading to dimeric cores, [Ln(2)(DNBA)(4)(DMF)(8)](2+); [Ln(2)(DNBA)(4)(DMF)(8)](2+) groups are joined together by pi-pi stacking interactions between the aromatic groups to form a two-dimensional grid-like network; the 2-D supramolecular layers are further extended into 3-D supramolecular networks with 1-D box-like channels by hydrogen-bonding interactions, in which hexamolybdate polyanions reside. The compounds represent the first examples of 3-D carboxylate-bridged lanthanide dimer supramolecular "host" networks formed by pi-pi stacking and hydrogen-bonding interactions encapsulating noncoordinating "guest" polyoxoanion species. The fluorescent activity of compound 3 is reported.     

Structural diversity for three Zn(II) coordination polymers from 4-nitrobenzene-1,2-dicarboxylate and bispyridyl ligand

Three Zn(II) complexes, [Zn₂(bpp)₂(FNA)₂]·H₂O (1), [Zn(bpp)(FNA)]·H₂O (2), and Zn₂(bpp)₂(FNA)₂ (3) (bpp = 1,3-bi(4-pyridyl)propane, H₂FNA = 4-nitrobenzene-1,2-dicarboxylic acid), were synthesized and characterized by single-crystal and powder X-ray diffraction methods, IR spectroscopy, TG analyses, elemental analyses, and fluorescent analysis. In 1, the Zn(II) ions are linked by FNA anions and bpp into 2-D layers. The Zn(II) ions in 2 are bridged by FNA anions into chiral chains, which are interlinked by bpp into 3-D metal–organic framework with (6⁵·8) CdS topology. Complex 3 features 1-D zigzag chains, which are interconnected by bpp ligands to give a 3-D framework with (6·7⁴·8)(6⁴·7·8) topology. Complexes 2 and 3 exhibit significant ferroelectric behavior (for 2 remnant polarization Pr = 0.050 μC cm^?2, coercive field Ec = 1.13 kV cm^?1, saturation of the spontaneous polarization Ps = 0.239 μC cm^?2; for 3 Pr = 0.192 μC cm^?2, Ec = 4.64 kV cm^?1, Ps = 0.298 μC cm^?2).     

A hydrogen-bonded,one-dimensional complex of cadmium(II) ions with 3,5-dinitrobenzoate and radicals: synthesis,characterization and crystal structure

A novel one-dimensional complex, [Cd(NIT4py)₂(DTB)₂(H₂O)₂] (1), (where NIT4py is 2-(4′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide and DTB is 3,5-dinitrobenzoate) has been synthesized and characterized by elemental analyses, IR and electronic spectra, single-crystal X-ray diffraction and magnetic measurements. The Cd(II) ion lies in a distorted octahedral environment with two nitrogen atoms from two NIT4py ligands and two oxygen atoms from two DTB molecules in the basal plane, and two oxygen atoms from two water molecules in axial positions. [Cd(NIT4py)₂(DTB)₂(H₂O)₂] units are connected to form one-dimensional chains by intermolecular hydrogen bonds. The complex exhibits intramolecular antiferromagnetic interactions.     

Intramolecular charge transfer complexes. 16. Copolymers of N,N-dimethyl-p-aminobenzyl methacrylate with acryloyl- and methacryloyl-β-hydroxyethyl-3,5-dinitrobenzoate

A new electronodonor monomer, N,N-dimethyl-p-aminobenzyl methacrylate (DMABM), was synthesized and radical copolymerized with two electronoacceptor monomers, acryloyl- (DNBA) and methacryloyl-(DNBM) β-hydroxyethyl-3,5-dinitrobenzoate, in order to obtain intramolecular charge-transfer-complex copolymers. Also, the small-molecular models of poly(DMABM), poly(DNBA), and poly(DNBM), the respective acetates, were synthesized and used to measure the values of ionization potential I_p of the donor and the electronic affinity E_a of the acceptor. They are I_p = 7.15 eV and E_a = 1.41 eV. The lower value of I_p as compared with that of carbazole derivatives is taken as evidence of a nonterminal mechanism of copolymerization. Also, from the ¹H-NMR and electronic spectra, the intramolecular complexation is discussed in terms of total transfer of the electron from donor to acceptor structural units.     

A disparate 3-D silver(I) coordination polymer of pyridine-3,5-dicarboxylate and pyrimidine with strong intermetallic interactions: X-ray crystallography,photoluminescence and antimicrobial activity

A polymeric silver(I) complex, [Ag₄(μ-pydc)₂(μ-pm)₂]_n (1) (pydc = pyridine-3,5-dicarboxylate and pm = pyrimidine), has been synthesized and characterized by elemental analysis, IR spectroscopy, thermal analysis, and single-crystal X-ray diffraction. X-ray crystallographic data of 1 revealed that pydc exhibits two different coordinaton modes that play a key role in the construction of the 3-D crystal network including Ag–carboxylate clusters in which close Ag–Ag distances exist. The magnitudes of close Ag–Ag interactions in second-order energy (E²) have been revealed by natural bond orbital analysis performed with single point energy calculation using the experimental geometry of 1. Furthermore, the luminescent properties of 1 show strong fluorescence with two emission maxima in the visible region. Also, 1 has antifungal activity on Candida albicans (MIC value, 4 μg mL^?1) and good antibacterial activity on micro-organisms (MIC value, 64–256 μg mL^?1).     

Thermal decompositions of scandium(III) 2,4-dinitrobenzoate, 3,5-dinitrobenzoate, 2,4-dichlorobenzoate and 3,4-diaminobenzoate in air atmosphere

The thermal decompositions of scandium 2,4-dinitrobenzoate, 3,5-dinitrobenzoate, 2,4-dichlorobenzoate and 3,4-diaminobenzoate were studied. On heating, the carboxylates decompose in two steps. The hydrated complexes first lose crystallization water and are transformed to Sc₂O₃. The dehydration of the complexes is accompanied by an endothermic effect and decomposition of the anhydrous or monohydrate complezes by strong exothermic effects. Scandium 2,4-dinitrobenzoate and 3,5-dinitrobenzoate decompose explosively.     

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.     

Syntheses,Crystal Structures,and Thermal Properties of Energetic Semicarbazide Salt,Manganese(II) Salt,and Coordination Compound of 3,5‐Dinitrobenzoic Acid

Nitro compounds have been actively researched as driven by their potential to be high‐performing energetic materials. Herein, three new nitro compounds including semicarbazide 3,5‐dinitrobenzoate, (SCZ)(DNBA), manganese 3,5‐dinitrobenzoate dihydrate, [Mn(DNBA)₂(H₂O)₂]_n, and bis(semicarbazide) manganese(II) 3,5‐dinitrobenzoate, Mn(SCZ)₂(DNBA)₂, were synthesized and characterized by elemental analysis, IR spectroscopy, and single‐crystal X‐ray diffraction analysis. The results indicated that the above mentioned compounds are ionic, polymeric, and molecular in nature, respectively. Moreover, their thermal decomposition properties were assessed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Their non‐isothermal reaction kinetics parameters, critical temperature of thermal explosion (T_bp), entropy of activation (ΔS^≠), enthalpy of activation (ΔH^≠), and free energy of activation (ΔG^≠) of the exothermic decomposition process were also calculated. Results suggest that there was a relationship between the structure and thermal stability.     

Crystal structures and magnetic properties of three cobalt(II)–organic frameworks with nanoscale channels

Three cobalt(II) coordination polymers, {[Co(nip)(4,4′-bpy)] · 3H₂O} _n (1), [Co(nip)(bpe)] _n (2), and [Co(nip)(bpp)(H₂O)] _n (3), were hydrothermally synthesized by the reaction of cobalt nitrate hexahydrate and nip with 4,4′-bpy, bpe, and bpp [nip = 5-nitro-1,3-benzenedicarboxylato, 4,4′-bpy = 4,4′-bipyridine, bpe = 1,2-bis(4-pyridyl)ethane, bpp = 1,3-bis(4-pyridyl)propane], respectively. Co(II) displays different coordination in the three complexes, resulting in different structures with nanoscale channels. Compounds 1 and 2 form 2-D layer structures, but 3 has a two-fold interpenetrated 3-D framework. The magnetic properties associated with their crystal structures were investigated.     

Rhenium(IV) and rhenium(V) complexes with 3,5-dimethylpyrazole

Mono-and dinuclear Re^IV and Re^V complexes with 3,5-dimethylpyrazole (Me₂pzH) were synthesized. The cis-[Re₂O₃Cl₄(3,5-Me₂pzH)₄] complex (cis-1) was prepared by the reaction of NH₄ReO₄ with K[HB(Me₂pz)₃] in concentrated HCl or by refluxing of [ReCl₃(MeCN)(PPh₃)₂] with Me₂pzH in air. The bromide complex trans-[Re₂O₃Br₄(3,5-Me₂pzH)₄] (trans-2) was synthesized by passing dry HBr through a solution of [Re₂O₃Br₂(μ-3,5-Me₂pz)₂(3,5-Me₂pzH)₂] (4) in chloroform. The pyrazolate-bridged complex [Re₂O₃Cl₂(μ-3,5-Me₂pz)₂(3,5-Me₂pzH)₂] (3) was prepared from (Et₄N)₂[ReOCl₅] or Cs₂[ReOCl₅] and Me₂pzH. The corresponding bromide and iodide complexes [Re₂O₃X₂(3,5-Me₂pz)₂(3,5-Me₂pzH)₂] · C₆H₆ (X = Br (4) or I (5)) were synthesized by the reactions of (NH₄)₂[ReBr₆] or K₂[ReI₆], respectively, with Me₂pzH. The [ReO(OMe)(3,5-Me₂pzH)₄]Br₂ · · 3,5-Me₂pzH · 4H₂O complex (6) was obtained as a by-product in the synthesis of complex 4. The reaction of [ReNCl₂(PPh₃)₂] with Me₂pzH was accompanied by hydrolytic denitration giving rise to the mixed-ligand complex [Re₂O₃Cl₂(μ-3,5-Me₂pz)₂(3,5-Me₂pzH)(PPh₃)] (7). The reaction of (NH₄)₂[ReBr₆] with a Me₂pzH melt gave the trans-[ReBr₄(3,5-Me₂pzH)₂] · · Me₂CO complex (8). The structures of complexes 2 and 4–8 were established by X-ray diffraction. All compounds were characterized by elemental analysis, electronic absorption spectroscopy, ¹H NMR and IR spectroscopy, mass spectrometry, and cyclic voltammetry. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 52–59, January, 2006.     

Three Mn(II) complexes with 1,3-bis(4-pyridyl)propane and their supramolecular nets

Three complexes, [Mn(bpp)₄(H₂O)₂](ClO₄)₂?·?1.5H₂O (1), [Mn(bpp)₃Br₂]?·?2H₂O (2), and [Mn(bpp)₂(H₂O)₂](ClO₄)?·?I?·?H₂O?·?bpp (3) (bpp?=?1,3-bis(4-pyridyl)propane), were synthesized and structurally characterized by single-crystal X-ray diffraction. Complex 1 is mononuclear where M(II) is coordinated to a monodentate TT-bpp, three monodentate TG-bpp, and two water molecules. Complex 2 possesses a single-stranded helical chain formed from MnN₄Br₂ octahedra by a single TT-bpp, with pendant monodentate TG-bpp ligands. Complex 3 consists of a ribbon-type double-stranded chain formed from MnN₄O₂ octahedra by double TG-bpp ligands. 2-D supramolecular architectures of 1–3 are formed by hydrogen bonds. The fluorescence of the three complexes comes from the π*–π transition of the ligand.     

Three Cu(II) (R)-2-chloromandelato complexes generated from dipyridyl-type ligands with different spacer lengths: syntheses,crystal structures,and ferroelectric properties

Three Cu(II) complexes, Cu₂(bpy)(H₂O)(Clma)₂ (1), Cu₂(bpe)(H₂O)₂(Clma)₂ (2), and Cu(bpp)(Clma) (3), were synthesized (HClma = (R)-2-Chloromandelic acid, bpy?=?4,4′-dipyridine, bpe?=?1,2-di(4-pyridyl)ethylene, bpp?=?1,3-di(4-pyridyl)propane). Complexes 1, 2, and 3 are constructed from 1-D coordination arrays generated from Cu₂(H₂O)(Clma)₂, Cu₂(H₂O)₂(Clma)₂, and Cu₂(Clma)₂ moieties and linked through bpy, bpe, and bpp co-ligands, respectively. 1 and 2 are assembled into 3-D supramolecular networks via O–H?O hydrogen bonds with topology of (6³)(6⁹·8) and (4¹²·6³), respectively, and 3 is assembled into a 3-D architecture through C–H?O hydrogen bonds with topology of (4³·6³)(4³)(4⁴·6⁵·8)(4⁶·6⁶·8³). Compounds 1, 2, and 3 crystallized in acentric space groups P2₁, P1, and P2₁, which exhibit significant ferroelectricity (remnant polarization Pr?=?0.008?μC?cm^?2, coercive field Ec?=?21.4?kV?cm^?1, the spontaneous saturation polarization Ps?=?0.167?μC?cm^?2 for 1, Pr?=?0.183?μC?cm^?2, Ec?=?1.69?kV?cm^?1, and Ps?=?0.021 μC?cm^?2 for 3). Results from infrared and thermal analyses are also discussed.     

Syntheses and characterization of three lanthanide(III) complexes containing pyridine-3,5-dicarboxylic acid and oxalic acid ligands

Direct reaction of pyridine-3,5-dicarboxylic acid (H₂PDA) and oxalic acid (H₂ox) with Ln(ClO₄)₃ · nH₂O under hydrothermal conditions gave three 3-D coordination networks, [Ln(PDA)(ox)_0.5(H₂O)₂] · H₂O [Ln = La(1), Nd(2), and Eu(3)]. The complexes were characterized by elemental analysis (EA), X-ray single-crystal diffraction, infrared spectroscopy (IR), and thermogravimetric analysis (TGA). Single crystal X-ray diffractions shows that the compounds are isomorphous and have 3-D framework structures, in which pyridine-3,5-dicarboxylates (PDA^2?) link lanthanides to give 2-D layers, which are further fabricated into a 3-D network via bis-bidentate oxalate bridging. Luminescence of 3 is investigated.     

Two lanthanide luminescent coordination compounds based on 3,5-pyrazoledicarboxylate and oxalic acid

Two isostructural 3-D complexes [Ln(pdc)(ox)_0.5(H₂O)₂]?H₂O (Ln = Tb(1), Eu(2); pdc = 3,5-pyrazoledicarboxylate; ox = oxalate) have been synthesized under hydrothermal conditions. Both are characterized by single crystal X-ray diffraction, elemental analysis, and IR. Compounds 1 and 2 possess a 3-D framework with 1-D rectangular channels built from 2-D, brick-like networks, and pdc ligands. The photoluminescence and lifetimes of 1 and 2 in the solid state have been studied.     

Synthesis and structure of trans-diaquabis(dimethylsulfoxide)bis(3,5-dinitrobenzoato)copper(II)

Single crystal of [Cu(DMSO)₂(3,5-DNB)₂(OH₂)₂], where DMSO-dimethylsulfoxide, 3,5-DNB-3,5-dinitrobenzoate, has been synthesized and its crystal structure is determined. Crystals belong to monoclinic symmetry, space group is P2₁/n, Z = 2, a = 10.911(4) Å, b = 5.362(2) Å, c = 22.673(7) Å, β = 92.06(2)°, V = 1325.8(1) ų, T = 293 K. Final value of R = 0.040 was obtained for 1804 independent reflections with I > 3σ(I). The structure is built from complex molecules.     

Cadmium(II), manganese(II) and zinc(II) compounds

Three new compounds, [Cd(μ ₃ -Hpdh)(μ₂-Cl)] _n (1), Mn(Hpdh)₂(H₂O)₂ (2) and Zn(Hpdh)₂ (H₂O)₂ (3) (H₂pdh =?pyridine-2,3-dicarbo-2,3-hydrazide), have been synthesized and characterized by elemental analysis, IR spectra, TG and single-crystal X-ray diffraction. Under hydrothermal conditions, H₂pdh is generated by an in situ acylation of H₂pda (H₂pda =?pyridine-2,3-dicarboxylic acid) with hydrazine hydrate. Complex 1 features a 2D layer structure constructed by a dinuclear Cd(II) building block. In complexes 2 and 3, hydrogen bonding interactions connect mononuclear structures into 3D supramolecular frameworks.