Supramolecular Network Structure Research Articles

Chlorine anion–π and π−–π− interactions in two tetrazolyl derivative based Cu2+ complexes and quantum chemical calculations

Two bis(tetrazolyl)amine (H2BTA) and 5,5′-azotetrazolate (AT) based Cu2+ supramolecular complexes [Cu(H2BTA)Cl2(H2O)]·2H2O (1) and [Cu2(AT)2(pn)3]·2H2O (2) (pn=1,3-diaminopropane) have been synthesized and characterized by single crystal X-ray diffraction analysis. In 1, each Cu2+ ion displays a tetragonal pyramidal structure and an anion–π of Cl−–π interaction has been observed. The Cl−–π binding interaction together with O–H···Cl, N–H···Cl, N–H···O and O–H···N four hydrogen bonds link the complex units and lattice water molecules to form a 3D supramolecular network structure. In 2, the Cu2+ ions show an elongated octahedral structure and a 1D chain structure bridged by μ2-trans-AT2− ligands is found. An unusual face-to-face π−–π− stacking interaction between trans-AT2− anions in 2 is found. Complex 2 also exhibits a 3D supramolecular structure in which the π−–π− stacking, O–H···N and N–H···O hydrogen bonding and electrostatic interactions are responsible for the stabilization of the complex. The aqueous solution of 2 shows photochromic property. The Cl−–π and π−–π− interaction energies in 1 and 2 were calculated at MP2 level using gaussian 09 suite and demonstrated.

Supramolecular chemistry of the ligand N,N’-bis(2-diphenylphosphinoethyl)phthalamide and its complexes with gold(I) and silver(I)

The dicarboxamide–diphosphine ligand N,N′-bis(2-diphenylphosphinoethyl)phthalamide, dpppa, which is prepared from 2-diphenylphosphinoethylamine and phthaloyl chloride, forms the binuclear gold(I) complex [Au2Cl2(μ-dpppa)], 1, and polymeric complex [{Ag2(μ-O2CCF3)2(μ-dpppa)}n], 2. The ligand and both complexes 1 and 2 undergo further association through hydrogen bonding to give supramolecular polymer or network structures.

Ferrocene–Tryptophan Conjugate: An Example of a Redox-Controlled Reversible Supramolecular Nanofiber Network

In this study, the tryptophan derivative of ferrocene-1,1′-dicarboxylic acid self-assembles in toluene to form a supramolecular nanofibrillar network structure. The ferrocene bioconjugate based nanofibers are responsive toward oxidation/reduction and show thermo and redox reversibility. Interestingly, redox-induced reversible morphological transformations between nanofiber and spheroid were observed. The self-assembly was characterized by 1H NMR spectroscopy, FT-IR spectroscopy, UV–vis spectroscopy, circular dichroism (CD), and transmission electron microscopy (TEM).

New photocatalyst for the degradation of organic dyes based on [Co2(1,4-BDC)(NCP)2]n·4nH2O

Abstract One metal–organic framework, [Co2(1,4-BDC)(NCP)2]n·4nH2O (1) (1,4-H2BDC denotes benzene-1,4-dicarboxylic acid, HNCP denotes 2-(4-carboxyphenyl)imidazo(4,5-f)(1,10)phenanthroline), has been hydrothermally synthesized and characterized via single crystal X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis and diffuse-reflectance UV–vis spectrum study. Compound 1 shows a 2D layer structure, which is further extended into a 3D supramolecular network structure through π–π stacking interactions. The photocatalytic study on compound 1 indicates that it is an active catalyst for the degradation of orange G, rhodamine B, methylene blue and methyl violet.

Cooperation of Hydrogen-Bond and Charge-Transfer Interactions in Molecular Complexes in the Solid State

Abstract Our recent studies for the development of conducting charge-transfer complexes with well-defined assembled structures based on the cooperation of hydrogen-bond and charge-transfer interactions are described. We have designed and synthesized hydrogen-bonded charge-transfer complexes based on (1) tetrathiafulvalene derivatives having nucleobases, aminobenzo and imidazole moieties, and (2) tetracyanoquinodimethane radical anion salts with hydrogen-bond-functionalized phenalenyl and protonated oligo(imidazole) cations. The directional and site-selective hydrogen-bonds formed various supramolecular network structures, constructing segregated columns as the conduction path. Furthermore, the high polarity of hydrogen-bonds caused strong donor–acceptor or cation–anion electrostatic interactions modulating the ionicity of component molecules and the electronic structure of conduction columns. Such electronic modulation effects in addition to controlling the molecular arrangement realized the first purely organic molecular metal based on a hydrogen-bonded charge-transfer complex in the p-chloranil complex of an imidazole-functionalized tetrathiafulvalene derivative. The proton-donating/accepting ability of the hydrogen-bonding sites afforded the simultaneous proton- and charge-transfer complexes, demonstrating an important prompt for the realization of cooperative proton–electron-transfer systems.

Racemic metal phosphonates based on 1-phosphonomethyl-2-benzimidazol-piperidine

Based on racemic 1-phosphonomethyl-2-benzimidazol-piperidine (pbpH2), three metal phosphonate compounds with the formula M(pbp)(H2O)2·3H2O [M = Ni(1), Co(2)] and Cu(pbp)·2H2O (3) have been synthesised and structurally determined. All of the compounds contain chiral chains, in which adjacent M(II) ions are linked solely by O–P–O bridges. In compounds 1 and 2, linear chains of the opposite handedness are fused by hydrogen bonds forming racemic double chains. The double chains are further connected by hydrogen bond interactions into a three-dimensional (3D) supramolecular network structure. In compound 3, helical chains with the opposite helicity are arranged alternately in the structure leading to a racemic 3D network. π–π stacking and hydrogen bond interactions are found to exist between the chains. Magnetic studies reveal that dominant antiferromagnetic interactions are propagated in 1–3 between the magnetic centers via the O–P–O pathways.

New halo(pseudohalo)cadmates templated by protonatated N-heterocyclic/diamine molecules

At ambient temperature, with various mono(di)protonated N-heterocyclic or diamine molecules as the cations, seven new halo(pseudohalo)cadmates [H2(bpee)][Cd(SCN)4] (bpee = 1,2-bis(4-pyridyl)ethene) 1, [H2(bpyp)][CdBr2(SCN)2] (bpyp = 1,2-bis(4-pyridyl)propane) 2, [H2(mbcha)][Cd3Br2(SCN)6] (mbcha = 4,4′-methylenebis(cyclohexylamine)) 3, [(Hdabco)2Cd3(SCN)8] (dabco = 1,4-diazabicyclo[2,2,2]octane) 4, [H2(bp)][Cd(SeCN)4] (bp = 4,4′-bipiperidine) 5 [H2(pdma)][Cd(SeCN)4]·2H2O (pdma = 1,4-phenylenedimethanamine) 6 and [H2(4,4′-dtdpy)][Cd2Br6] (dtdpy = dithioidipyridine) 7 were obtained. X-ray analysis revealed that (i) compound 1 possesses a three-dimensional (3D) supramolecular network structure with the one-dimensional (1D) channels, constructed from the inorganic [Cd(SCN)4]2− chains by weak S⋯S interactions. The H2(bpee)2+ molecules occupy the space of the channels; (ii) with H2(mbcha)2+ as the cation, the anion [Cd3Br2(SCN)6]2− of compound 3 exhibits a 1D ribbon structure, which can be described as a lengthways packing of planar bi-bridged trimers; (iii) compound 4 is the first example of the cation-controlled 3D thiocyanatocadmate with a composition [Cd3(SCN)8]2−; (iv) with H2(4,4′-dtdpy)2+ as the cation, the anion [Cd2Br6]2− of compound 7 also shows a 1D ribbon structure. This ribbon can be described as a transverse stacking of two planar bi-bridged single chains; (v) the ribbons of compounds 3 and 7 can be visualized as a slice of the two dimensional (2D) CdX2 layer; (vi) in compounds 2, 3, 5, 6 and 7, the organic molecules as the linkers extend the inorganic anionic moieties into various 2D supramolecular layer networks.

Syntheses, structures and magnetic properties of two heterometallic carbonates: K2Li[Cu(H2O)2Ru2(CO3)4X2]·5H2O (X = Cl, Br)

Self-assembly of Ru2(CO3)43− units and Cu2+ ions in the presence of halogen (Cl− or Br−) has resulted in two novel isomeric layered structural heterometallic carbonates, K2Li[Cu(H2O)2Ru2(CO3)4X2]·5H2O [X = Cl (1), Br (2)]. X-ray structural analysis reveals that complexes 1 and 2 contain a similar square-grid negative layer [Cu(H2O)2Ru2(CO3)4X2]n5n−, in which each Ru2(CO3)4X25− unit is linked by four Jahn–Teller distorted Cu(H2O)22+ ions in a cross mode and vice versa. The adjacent negative layers are connected by K–O, Li–O bonds, and hydrogen bonding, which led to the formation of a supramolecular 3D network structure. The two complexes show ferromagnetic coupling between the Ru2 dimer and the Cu2+ ion. Detailed magnetism measurement demonstrates that complex 1 exhibits soft magnetic ordering below 2.9 K coexistent with domain movement, and complex 2 shows long-range ferromagnetic ordering below 3.8 K.

Synthesis, Characterization, and Crystal Structure of a Supramolecular CoII Complex Containing Salen-Type Bisoxime

A supramolecular CoII complex, [CoL(H2O)2], bearing Salen-type bisoxime chelate ligand 4,4′,6,6′-tetrachloro-2,2′-[ethylenedioxybis(nitrilomethylidyne)]diphenol (H2L), has been synthesized and structurally characterized by elemental analyses, IR spectra, UV–vis spectra, and X-ray diffraction techniques. The crystal structure of [CoL(H2O)2] indicates that the CoII complex consists of one CoII atom, one L2– unit, and two coordinated water molecules. The CoII complex exhibits slightly distorted octahedral geometry with the Salen-type bisoxime ligand forming the basal N2O2 coordination plane and two oxygen atoms from the coordinated water molecules in the axial positions. An infinite 1D metal–water chain and 2D supramolecular network structure were formed by intermolecular O-H···O, O-H···Cl, and C-H···O hydrogen bonding and π-π stacking interactions. 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.

Mixed-solvothermal synthesis, structures, luminescent and surface photovoltage properties of four new transition metal diphosphonates with a 3D supramolecular structure

Four new transition metal(II) diphosphonates with a 3D supramolecular structure, M(hedpH2)3·3NH2(CH3)2NH(CH3)3·3H2O (M = Mn (1), Co (2), Ni (3), Zn (4); hedpH4 = 1-hydroxyethylidenediphosphonate acid) have been synthesized under mixed-solvothermal conditions and structurally characterized. Compounds 1–4 are isomorphous and adopt a three-dimensional supramolecular network structure containing {M(hedpH2)3}4− cluster units. The interconnection of {MO6} and {CPO3} polyhedra via corner-sharing forms a {M(hedpH2)3}4− cluster, and these isolated clusters are extended by hydrogen bonds to form a two-dimensional layer structure, which are further connected through hydrogen bonding interactions to give rise to a 3D supramolecular structure. Surface photovoltage spectroscopy (SPS) of compounds 1–4 indicates that it possesses positive SPV response in the range of 300–600 nm and shows p-type semiconductor characteristic. Luminescence properties of the four compounds have also been studied.

A series of novel gallium and indium borates constructed from [B5O8(OH)2]3− clusters and metal complex linkers

Four novel gallium and indium borates, [M(en)2][B5O8(OH)2]·H2O (M=Ga (1), In (2); en=ethylenediamine), [In(dap)2][B5O8(OH)2]·H2O (3, dap=1,2-diaminopropane), [In(dien)][B5O8(OH)2] (4, dien=diethylenetriamine), have been hydrothermally synthesized and characterized by IR spectra, elemental analyses, powder X-ray diffraction, single crystal X-ray diffraction, and thermogravimetric analyses. Compounds 1, 2 and 3 are isostructural and consist of one-dimensional (1-D) chains built up from [B5O8(OH)2]3− clusters and Ga-/In-complex linkers. The structure of compound 4 features a 1-D chain containing 8-member rings built by [B5O8(OH)2]3− clusters and {In2O4} dimeric cluster linkers which have never observed in the structural chemistry of borates to date. The H-bonding interactions between adjacent chains lead to 3-D supramolecular network structure.

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.

Oxidation of Dimethylplatinum(II) Complexes with a Dioxirane: The Viability of Oxoplatinum(IV) Intermediates

The complexes [PtMe2(NN)] (NN = 2,2′-bipyridine = bipy, 1a; NN = di-2-pyridylamine = dpa, 1b; NN = di-2-pyridyl ketone = dpk, 1c) react with dimethyldioxirane in moist acetone to give the hydroxoplatinum(IV) complexes [Pt(OH)2Me2(NN)] (NN = bipy, 2a; NN = dpa, 2b, or [Pt(OH)Me2(dpkOH)], 3). Complex 2a crystallizes as the hydrate 2a·7H2O, which has a complex supramolecular network structure formed through hydrogen bonding between PtOH groups and water molecules. Attempts to trap a potential oxoplatinum(IV) intermediate in these reactions were unsuccessful, and computational studies suggest that oxoplatinum(IV) intermediates are improbable. It is suggested that oxygen atom transfer from the dioxirane to platinum is coupled to proton addition to give the hydroxoplatinum group directly.

A tetradentate bisoxime and its supramolecular nickel(II) cluster: synthesis, crystal structure, and spectral properties

Salen-type bisoxime 5,5′-dimethoxy-2,2′-[(ethylenedioxy)bis(nitrilomethylidyne)]diphenol (H2L) and its trinuclear Ni(II) cluster {[(NiL)(n-BuOH)]2(μ-OAc)2Ni} · n-BuOH have been synthesized and structurally characterized. The structure of H2L adopts an L-shape conformation where the two salicylaldoxime moieties are well separated. In the trinuclear Ni(II) cluster, two acetates coordinate to three Ni(II)'s through Ni–O–C–O–Ni bridges, four μ-phenoxos from two [NiL(n-BuOH)] units also coordinate to Ni(II), and two n-butanols coordinate to two terminal Ni(II)'s forming a distorted octahedral geometry. The Ni–O–C–O–Ni and μ-phenoxo bridges play important roles in assembling Ni(II) and the ligands. H2L forms a rectangle-like large cave structure through O–H ··· N, C–H ··· O, and C–H ··· π hydrogen-bond interactions, whereas its trinuclear Ni(II) cluster exhibits a 3-D supramolecular network structure through intermolecular O–H ··· O, C–H ··· O, and C–H ··· π hydrogen-bond interactions.

Synthesis, crystal structures and luminescent properties of two one-dimensional cadmium(II) coordination polymers generated from polydentate Schiff-base ligand

Two new one-dimensional coordination polymers {[CdL2(H2O)2](NO3)2(H2O)6}n (1) and {[CdLI2](H2O)(CH3OH)}n (2) have been synthesized and characterized by IR, elemental analysis, TG technique, XRPD and complete single crystal structure analyses, where L is bis(pyridin-4-ylmethylene)biphenyl-2,2′-dicarbohydrazide. The Cd(II) atom has a distorted octahedral coordination geometry with N4O2 donors from four ligands and two water molecules in 1 and a distorted tetrahedral coordination geometry with NOI2 donors from two ligands and two I− anions in 2, respectively. Polymer 1 shows a 1D framework structure containing bimetallic 42-membered quadrangular ring units. The adjacent 1D chains are interacted forming a 3D supramolecular network structure through multiform hydrogen bond interactions. In comparison with 1, polymer 2 is a new rampart-type chain and each chain is interacted with each other through hydrogen bond interactions to lead a 2D layer. The luminescent properties of the polymers 1 and 2 were investigated in the solid state at room temperature.

A new two dimensional copper (II) coordination complex with sulphonamide: Synthesis, crystal structure and DNA binding study

Abstract A novel copper (II) complex, [Cu(HL)2] (where, HL = 3-(4-(sulphonamine)phenylimino)-1-phenylbut-1-en-1-ol) has been synthesized and characterized by IR, UV–vis, magnetic susceptibility measurement and single crystal X-ray crystallographic studies. The crystal data confirm the square planarity of the prepared complex having an orthorhombic space group Pca2 (1). Molecular packing of the complex is stabilized by N―H…O hydrogen bonding and weak N―H…O, C―H…Cg π-ring intermolecular interactions, hence forming a two dimensional supramolecular network structure. CT-DNA binding studies have been carried out by monitoring electronic absorption titrations, luminescence titrations, a DNA melting, cyclic voltametry and viscosity measurement studies. An intercalative mode of DNA binding is suggested for the prepared copper (II) complex.

Construction of two Novel 2D Coordination Frameworks with the Ligand H3nbtc: Synthesis, Crystal Structures, and Luminescence

AbstractTwo novel 2D coordination polymers, namely, {[Cu2(L)2][Cu(H2O)3]}n (1) and {Pb3(O2N‐btb)2}n (2) (O2N‐H3btb = 5‐nitro‐benzene‐1, 2, 3‐tricarboxylic acid, L = 5‐nitro‐2‐oxidoisophthalate), were synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectroscopy, X‐ray diffraction, and thermogravimetric analysis. Compound 1 is an infinite 2D layer exhibiting an extended 3D supramolecular network structure. O–H···O hydrogen bonding interactions play a key role in forming the final 3D supramolecular framework. It is noted that 5‐nitro‐benzene‐1, 2, 3‐tricarboxylic acid (O2N‐H3btb) was in situ transformed to 5‐nitro‐2‐oxidoisophthalate in 1. Compound 2 is a 2D microporous lead‐containing metal‐organic framework made up of interconnected Pb‐carboxylate chains, involving three independent lead atoms with three different coordination arrangements. Furthermore, the solid‐state photoluminescence and lifetime characteristics of 2 reveal intense blue luminescence.

“Liquid-like” type (COO−)2(H2O)10 anion water clusters in three-dimensional supramolecular structure of cucurbit[6]uril

The three-dimensional (3D) supramolecular network structure of the guest 1,1′-(hexane-1,6-diyl)dipyridinium-4-carboxylate inner salt (HBPC) and the host cucurbit[6]uril (CB[6]) is self-assembled through an intricate array of hydrogen-bonding interactions involving the contributions of two-dimensional (2D) infinite network (COO−)2(H2O)10 anion water clusters and (H2O)2 water clusters. These water clusters are notably have the liquid-like water characteristics in the solid and are reversibly dehydrated and rehydrated, while the pseudorotaxane retains its integrity in the process, and is stable up to 390 °C.

Four new cobalt(ii) coordination complexes: thermochromic switchable behavior in the process of dehydration and rehydration

Four cobalt(II) coordination complexes, {[Co11(L1)6(HL1)2(H2O)28]·12H2O}n (1), [Co4(H2L1)4(HL1)2(H2O)8]·2H3L1·2H2O (2), {[Co(H2L3)(H2O)3]·2H2O}n (3) and [Co(HL1)(4,4′-bpy)(H2O)2]n (4), (H3L1 = 2,4,6-tri(3-carboxyphenylthio)-1,3,5-triazine, H4L3 = 2,4-bis(3-carboxyphenylthio)-6-(4-carboxyphenylamino -1,3,5-triazine, 4,4′-bpy = 4,4′-bipyridine), was synthesized hydrothermally and characterized by single-crystal X-ray diffraction, powder X-ray diffraction, IR, thermal analysis, UV-vis spectroscopy and magnetic measurements. Complex 1 shows a 2D layer structure composed of three types of secondary building units (SBUs), [M1], [M3] and [M4] bridged by [HL1]2− and [L1]3− linkers. While complex 2 is a tetranuclear compound and further forms a 3D supramolecular network structure based on eight types of hydrogen-bonding interactions between the molecules. The 2D framework of complex 3 can be described as 1D infinite chains interconnected by [H2L3]2− ligands. Furthermore, the hydrogen-bonding interactions between the adjacent layers along the ac plane makes the 2D layer structure extend to a 3D network. The structure of complex 4 can be illustrated as a 1D zigzag infinite chain with 4,4′-bipyridine as the secondary ligand. Additionally, the π⋯π stacking interactions can be observed between the adjacent chains. An aquo-accessible thermochromic change in complexes 1–4 was induced by means of the reversible dehydration and rehydration of the crystals. Magnetic measurements showed antiferromagnetic coupling between the Co2+ ions in all of the four complexes.

Organogels formed in various organic solvents by different alkyl L-phenylalanine dihydrazide derivatives

A new group of organogelators, L-phenylalanine dihydrazide derivatives were synthesized, which can self-assemble in various organic solvents and turned them into thermally reversible physical supramolecular organogels at extremely low concentrations (<2 wt %). Scanning electron microscopy measurements revealed that the gelator self-assembled into different supramolecular network structures in different solvents. FT-IR spectroscopy studies revealed that intermolecular hydrogen bonding between N-H and C=O of amide group and hydrophobic interaction of the alkyl groups were the driving forces for the formation of the gels. Based on the data of XRD and molecular modeling, one possible packing mode for the formation of organogelator aggregates was proposed.