Two-dimensional Supramolecular Architecture Research Articles

Noncoordinating Anions as Key Modulators of Supramolecular Structures, Optical and Electrical Properties in Nickel(II) Complexes.

This study explores the synthesis, structural characterization, and examination of two nickel(II) complexes, [Ni(N 3 L 1 )2](NO3)2 (complex 1) and [Ni(N 3 L 1 )2](ClO4)2 (complex 2), using the newly synthesized organic heterocyclic chelating ligand N 3 L 1 [4-imidazole-2,6-di(pyrazinyl)pyridine]. Through single-crystal X-ray diffraction, we have detailed the crystal structures of these complexes, highlighting their distorted octahedral geometries and diverse supramolecular interactions including π···π stacking, anion···π, and hydrogen bonding. These interactions crucially influence the formation of distinct one- and two-dimensional supramolecular architectures. Density functional theory (DFT) calculations were utilized to probe these noncovalent interactions, revealing insights into their stereoelectronic influence and stability in the solid state. Additionally, the electronic properties of the complexes were explored through their electrical characterizations in Schottky diodes, which suggest the potential of these complexes in Schottky diode based electronic devices applications. Notably, complex 2, incorporating perchlorate anions, exhibited better electrical properties than complex 1. This work aims to elucidate the role of noncoordinating counteranions in the structural integrity and photophysical behavior of these complexes, while also providing a structure-function correlation through detailed theoretical analysis.

Fabrication of a parallel interpenetrating 2D hydrogen-bonded zig-zag Zn(II) coordination polymer: Characterization and band gap study

A Zn(II) based coordination polymer (CP) [Zn2(cis,cis-muco)2(bpe)2(H2O)2] (1) (H2cis,cis-muco = cis,cis-muconic acid and bpe = 1,2-bis(4-pyridyl)ethylene) has been synthesized by slow diffusion method at room temperature. The structure determination by single crystal X-ray diffraction (SCXRD) technique reveals that compound 1 consists of one-dimensional (1D) zig-zag chain with distorted tetrahedral Zn(II) center. The 1D chain forms two-dimensional (2D) supramolecular architecture by means of ample hydrogen bonding interactions. Hirshfeld surface analysis effectively measures the strength of non-covalent interactions present in compound 1. Density functional theory (DFT) computation method is used to observe the semiconducting nature of compound 1 by HOMO-LUMO band-gap calculation, which is in well agreement with the value obtained experimentally by optical study. Thus the synthesized compound 1 may be utilized in the fabrication of semiconducting device.

Six nickel-lanthanoid heterometallic complexes based on 2,5-dichlorobenzoate and phen: Syntheses, structures and magnetic properties

Six new zero-dimensional (0D) Ni(II)-Ln(III) heterometallic complexes, [Ln2Ni2(2,5-DCB)10(phen)2] [Ln = Nd (1), Sm (2), Eu (3), Gd (4), Tb (5) and Dy (6), 2,5-HDCB = 2,5‑dichlorobenzoic acid, phen = 1,10-phenanthroline], have been successfully synthesized by the reactions of Ln(NO3)3·6H2O, Ni(NO3)2·6H2O, 2,5‑dichlorobenzoic acid, NaOH and 1,10-phenanthroline under solvothermal conditions. All of these complexes have been characterized by single-crystal X-ray diffraction, elemental analysis, FT-IR spectroscopy, powder X-ray diffraction (PXRD) and thermogravimetric analysis (TGA) and differential thermoanalysis (DTA). Complexes 1–6 are isomorphous and have a linear tetranuclear cluster structure formed by the 2,5-DCB anions linking the Ni(II) and Ln(III) ions. The adjacent tetranuclear molecules are further extended into a two-dimensional (2D) supramolecular architecture by the π–π interactions. The magnetic properties of 1, 2 and 4–6 were investigated in detail. Complex 6 displays a field-induced single-molecule magnet (SMM) behavior with a Ueff value of 10 K.

Crystal structure and Hirshfeld surface analysis of 3-({4-[(4-cyano-phen-oxy)carbon-yl]phen-oxy}carbon-yl)phenyl 4-(benz-yloxy)-3-chloro-benzoate.

The title compound, C35H22ClNO7, is a non-liquid crystal with a bent-shaped mol-ecule. The dihedral angles between adjacent aromatic rings in the mol-ecule (starting from the cyano-benzene ring) are 72.61 (2), 87.69 (4), 64.08 (2) and 88.23 (2)°, indicating that adjacent rings are close to perpendicular to each other. In the crystal, the mol-ecules are linked by weak C-H⋯N and C-H⋯π inter-actions, thereby forming a two-dimensional supra-molecular architecture in the ac plane. The most important contributions to the crystal packing arise from H⋯H (59.3%), S⋯H (27.4%) and O⋯H (7.5%) inter-actions, as determined by a Hirshfeld surface analysis.

Monte Carlo simulations of the self-assembly of hierarchically organized metal-organic networks on solid surfaces

The coordination-driven self-assembly of two-dimensional (2D) supramolecular architectures is a convenient method of rational construction of one-atom-thick nanomaterials with desired topology, intriguing physicochemical properties and high cognitive value. In this work, we use coarse-grained Monte Carlo (MC) computer simulations to study the self-assembly of functional bridging ligands with mononuclear metal centers on a triangular lattice. Particularly, we focus on the role of anisotropic, reversible ligand → metal coordinate bonds in the bottom-up formation of hierarchically organized metal-organic networks composed of star-shaped and rod-like linkers (representing real organic molecules) and trivalent metal atoms. In our model π aromatic ligands were modeled in a simplified way as a collection of flat, rigid, and interconnected segments with properly encoded short-ranged interactions. Depending on the composition of the investigated overlayers, we observed the spontaneous formation a cascade of openwork (co)crystals with a hierarchical structure, controllable chirality and scalable morphological properties like porosity, connectivity, density, etc. Our theoretical findings can pave the way for the experimental fabrication of the novel surface-confined metal-organic networks (SMONs) in which anisotropic coordinate bonds play a decisive role.

Crystal structure and Hirshfeld surface analysis of bis-[(eth-oxy-methane-thio-yl)sulfanido](N,N,N',N'-tetra-methyl-ethane-1,2-di-amine)-mercury(II).

The title four-coordinate mononuclear complex, [Hg(C3H5OS2)2(C6H16N2)] or [Hg(C3H5OS2)2(tmeda)] (tmeda: N,N,N',N'-tetra-methyl-ethane-1,2-di-amine), has a distorted tetra-hedral geometry. The HgII ion is coordinated to two N atoms of the N,N,N',N'-tetra-methyl-ethylenedi-amine ligand and two S atoms from two ethylxanthate xanthate ligands. In the crystal, mol-ecules are linked by weak C-H⋯S hydrogen bonds, forming a two-dimensional supra-molecular architecture in the ab plane. The most important contributions for the crystal packing are from H⋯H (59.3%), S⋯H (27.4%) and O⋯H (7.5%) inter-actions.

Synthesis and crystal structure of one new Pb(II) complex constructed by 1,10-phenanthroline and two carboxylate ligands

Abstract The complex [Pb(phen)(4-NB)(CH3COO)] of lead(II) was prepared and characterized by means of elemental analysis, FT-IR, and single crystal X-ray analysis, where phen = 1,10-phenanthroline, 4-NB = 4-nitrobenzoate. The single crystal X-ray analysis indicates that the complex is a monomeric species, including two carboxylate ligands, and adopts a hemidirected structure. It is further extended by intermolecular C−H⋯O hydrogen bonds, π–π interactions and secondary Pb⋯O interactions to form two-dimensional supramolecular architecture.

Spectral studies and crystal structures of molybdenum(VI) complexes containing pyridine or picoline as auxiliary ligands: interaction energy calculations and free radical scavenging studies

Three cis-MoO2 complexes [MoO2(CAB)(py)] (1), [MoO2(CAB)(3-pic)] (2) and [MoO2(CAB)(4-pic)] (3) which vary in the nature of the heterocyclic bases in the auxiliary coordination site derived from an ONO donor aroylhydrazone (H2CAB) have been synthesized and characterized by various physicochemical methods. The single-crystal X-ray diffraction studies reveal that the complexes adopt a distorted octahedral N2O4 coordination sphere around the Mo(VI) center in which the ONO donor atoms of hydrazone moiety and one oxido oxygen constitute the NO3 basal plane and the axial position by the other oxido oxygen and nitrogen atom of coordinated pyridine molecule in [MoO2(CAB)(py)] (1) or picoline molecule in [MoO2(CAB)(3-pic)] (2) and [MoO2(CAB)(4-pic)] (3). The hydrogen bonding interaction generates a two-dimensional supramolecular sheet-like architecture in [MoO2(CAB)(py)] (1) and [MoO2(CAB)(3-pic)] (2), whereas a three-dimensional network was observed in [MoO2(CAB)(4-pic)] (3). The interaction energy calculations reveal that the dispersion energy component dominates over other components and [MoO2(CAB)(3-pic)] (2) is found to be energetically more stable. Furthermore, the aroylhydrazone shows free radical scavenging activity, whereas the complexes are inactive.

Simultaneous Spin-Crossover Transition and Conductivity Switching in a Dinuclear Iron(II) Coordination Compound Based on 7,7',8,8'-Tetracyano-p-quinodimethane.

Invited for the cover of this issue are Ryuta Ishikawa and Satoshi Kawata at Fukuoka University and co-workers at Osaka University, Tohoku University, and Kumamoto University, Japan, collaborating within the research project "SOFT CRYSTALS". The image depicts the thermally induced simultaneous switching of magnetism and electrical conductivity in a two-dimensional supramolecular architecture composed of dinuclear FeII spin-crossover complexes and partially charged 7,7',8,8'-tetracyano-p-quinodimethanide radicals. 10.1002/chem.201903934.

A new one-dimensional Cd(II) coordination polymer with a two-dimensional supramolecular architecture: synthesis, structural characterization and fluorescence properties

Abstract A new coordination polymer [Cd(C10H8N2)2 (C10H4O8)] n (C10H8N2 = 2,2′-bipyridine and C10H4O8 = 2,5-dicarboxybenzene-1,4-dicarboxylate) has been hydrothermally synthesized and characterized by elemental analysis, infrared spectroscopy, thermal gravimetric analysis and single-crystal X-ray diffraction. Crystal structural analysis reveals that the CdII cation is coordinated by two 2,5-dicarboxybenzene-1,4-dicarboxylate ligands and two 2,2′-bipyridine molecules, forming a distorted octahedral CdN4O2 coordination geometry. The 2,5-dicarboxybenzene-1,4-dicarboxylate ligands link the CdII cations to generate a one-dimensional metal-organic structure running along the [0 1 0] direction. Adjacent chains are further connected by carboxyl-carboxyl O–H···O hydrogen bonds, resulting in a two-dimensional supermolecular architecture running parallel to the (1 0 0) plane in the solid state. The fluorescence properties of the complex were investigated.

Synthesis, structure characterization, photoluminescence properties and TD-DFT calculations for two new borates.

Due to their rich structural chemistry and wide variety of applications, borate materials have provided a rich area of research. In a continuation of this research, diethylammonium bis(2-oxidobenzoato-κ2O1,O2)borate, C4H12N+·BO4(C7H4O)2-, (1), and propylammonium bis(2-oxidobenzoato-κ2O1,O2)borate, C3H10N+·BO4(C7H4O)2-, (2), have been synthesized by the reaction of boric acid with salicylic acid under ambient conditions. In both structures, the B atom exhibits a slightly distorted tetrahedral environment formed by the bidentate coordination of two salicylate anions via the O atoms of the central carboxylate and oxide groups. In the crystals of salts (1) and (2), mixed cation-anion layers lying parallel to the (101) plane are formed through N-H...O, C-H...O and C-H...π/N-H...O hydrogen-bonding interactions, resulting, in each case, in a two-dimensional supramolecular architecture in the solid state. The photoluminescence properties of the salts were studied using the as-synthesized samples and reveal that salts (1) and (2) both display a strong blue-light emission, with maxima at 489 and 491 nm, respectively. In DFT/TD-DFT (time-dependent density functional theory) studies, the blue emission appears to be derived from an intramolecular charge transfer (ICT) excited state. In addition, IR and UV-Vis spectroscopies were used to investigate the title salts.

A one-dimensional Cd(II) coordination polymer with a two-dimensional supramolecular architecture through halogen···halogen interaction

ABSTRACTA new cadmium coordination polymer, formulated as [Cd(L)(phen)]n, were prepared by hydrothermal reactions based on 3,4-dibromothiophene-2,5-dicarboxylic acid (H2L) and 1,10-phenanthroline (phen) mixed organic linkers. In the complex, adjacent Cd2+ ions are linked by L2− anions to form a one-dimensional (1D) [CdL]n chain with [Cd2(COO)2] as the secondary building unit (SBU). These adjacent chains are further stacked together by direct C−Br···Br halogen bonds interactions, generating a two-dimensional (2D) supramolecular structure. From the viewpoint of topology, the 2D supramolecular network can be rationalized to a 3,4-connected 3,4L13 net with {4.62}2{42.62.82} topology.

A new one-dimensional NiII coordination polymer with a two-dimensional supra-molecular architecture.

A new one-dimensional NiII coordination polymer of 1,3,5-tris-(imidazol-1-ylmeth-yl)benzene, namely catena-poly[[aqua-(sulfato-κO)hemi(μ-ethane-1,2-diol-κ2O:O')[μ3-1,3,5-tris-(1H-imidazol-1-ylmeth-yl)benzene-κ3N3,N3',N3'']nickel(II)] ethane-1,2-diol monosolvate monohydrate], {[Ni(SO4)(C18H18N6)(C2H6O2)0.5(H2O)]·C2H6O2·H2O} n , was synthesized and characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. The NiII cation is coordinated by three N atoms of three different 1,3,5-tris-(imidazol-1-ylmeth-yl)benzene ligands, one O atom of an ethane-1,2-diol mol-ecule, by a sulfate anion and a water mol-ecule, forming a distorted octa-hedral NiN3O3 coordination geometry. The tripodal 1,3,5-tris-(imidazol-1-ylmeth-yl)benzene ligands link the NiII cations, generating metal-organic chains running along the [100] direction. Adjacent chains are further connected by O-H⋯O hydrogen bonds, resulting in a two-dimensional supermolecular architecture running parallel to the (001) plane. Another water mol-ecule and a second ethane-1,2-diol mol-ecule are non-coordinating and are linked to the coordinating sulfate ions via O-H⋯O hydrogen bonds.

A bismuth-based fluorous metal-organic framework for efficient degradation of Congo red

Abstract A new bismuth-based fluorous metal-organic framework, [Bi(OOCC6F5)3(C10H8N2)(H2O)2], (OOCC6F5 = pentafluorobenzoate, C10H8N2 = 2,2′-bipyridine)(1) is synthesized by a hydrothermal method. Compound 1 crystalizes in the P21/c space group, exhibiting a two-dimensional supramolecular architecture by intermolecular C H⋯F C interactions between the hydrogen atoms in 2,2′-bipyridine and fluorine atoms in adjacent perfluorophenyl rings. In addition, compound 1 shows excellent properties of degradation Congo red in the absence of UV–vis radiation. Moreover, adsorption kinetics study suggested that the adsorption of Congo red belongs to first-order reaction kinetics. Our results indicated that bismuth-based FMOFs could be promising candidates for the development of efficient degradation of organic dye.

A threefold interpenetrated two-dimensional zinc(II) supramolecular architecture based on 3-nitrobenzoic acid and 4,4'-bipyridine.

With regard to crystal engineering, building block or modular assembly methodologies have shown great success in the design and construction of metal-organic coordination polymers. The critical factor for the construction of coordination polymers is the rational choice of the organic building blocks and the metal centre. The reaction of Zn(OAc)2·2H2O (OAc is acetate) with 3-nitrobenzoic acid (HNBA) and 4,4'-bipyridine (4,4'-bipy) under hydrothermal conditions produced a two-dimensional zinc(II) supramolecular architecture, catena-poly[[bis(3-nitrobenzoato-κ(2)O,O')zinc(II)]-μ-4,4'-bipyridine-κ(2)N:N'], [Zn(C7H4NO4)2(C10H8N2)]n or [Zn(NBA)2(4,4'-bipy)]n, which was characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis and single-crystal X-ray diffraction analysis. The Zn(II) ions are connected by the 4,4'-bipy ligands to form a one-dimensional zigzag chain and the chains are decorated with anionic NBA ligands which interact further through aromatic π-π stacking interactions, expanding the structure into a threefold interpenetrated two-dimensional supramolecular architecture. The solid-state fluorescence analysis indicates a slight blue shift compared with pure 4,4'-bipyridine and HNBA.

Synthesis, Crystal Structure, Physical Properties and Theoretical Calculations of a New One-Dimensional Ni(II) Coordination Polymer Constructed by 1,10-Phenanthroline Derivative Ligand and Sulfate

A new Ni(II) coordination polymer constructed by 1,10-phenanthroline derivative 2-(2-chloro-6-fluorophenyl)-1H-imidazo[4,5-f][1, 10]phenanthroline (L) and inorganic sulfate anion, namely, [Ni(L)(SO4)(H2O)2]n (1), has been successfully synthesized under hydrothermal condition. In compound 1, each sulfate functions in bidentate bridging coordination mode and links two Ni(II) atoms to generate a one-dimensional chain structure. The adjacent chains are joined together by aromatic π–π interactions between L ligands to yield a two-dimensional supramolecular layer. The O–H···O and N–H···O hydrogen bonding interactions between sulfate oxygen atoms, coordination water molecules and nitrogen atoms of L ligands further stabilize the two-dimensional supramolecular architecture of 1. Moreover, the magnetic property of 1 was investigated. In addition, natural bond orbital analysis was performed by the B3LYP/LANL2DZ method in Gaussian 09 Program. The calculation results show the obvious covalent interaction between the coordinated atoms and Ni(II) ion.

Crystal structure of bis-[μ-bis-(di-phenyl-phosphan-yl)methane-κ(2) P:P']-μ-chlorido-chlorido-1κCl-(1-phenyl-thio-urea-2κS)disilver aceto-nitrile hemisolvate.

In the dinuclear title complex, [Ag2Cl2(C7H8N2S)(C25H22P2)2]·0.5CH3CN, each AgI ion displays a distorted tetra­hedral coordination geometry with two P atoms from two bis­(di­phenyl­phosphan­yl)methane (dppm) ligands, one bridging chloride ion, one terminal chloride ion and one terminal S atom from the N,N′-phenyl­thio­urea (ptu) ligand. The dppm ligands and the bridging chloride ion force the two Ag atoms into close proximity, with a short Ag⋯Ag separation of 3.2064 (2) Å. In the crystal, complex mol­ecules are linked by N—H⋯Cl hydrogen bonds forming a dimer. The dimers are linked via weak C— H⋯Cl hydrogen bonds forming a two-dimensional supra­molecular architecture in the yz plane. In addition, an intra­molecular N—H⋯Cl hydrogen bond is observed.

Synthesis, characterisation and fluorescence property of a new one-dimensional polymer constructed from 5-nitroisophthalic acid

A new metal-organic coordination polymer [Zn(5-nip)(2,2′-bipy)]·1·5H2O (1) (5-nip = 5-nitroisophthalic acid; 2,2′-bipy = 2,2′-bipyridine) was synthesised by using hydrothermal reaction of 5-nip, Zn(NO3)2·6H2O as well as 2,2′-bipy. Combined with the characterisation of elemental analysis, infrared spectrum, thermogravimetric analysis and X-ray single crystal diffractometer, it shows that the complex exhibits an infinite one-dimensional zigzag chain that was constructed with repeated units of [Zn(5-nip)(2,2′-bipy)]·1·5H2O. In each units, the metal Zn(II) centre was coordinated by 2,2′-bipy and 5-nip ligands with five-coordinated number. While the 5-nip ligands link the Zn(II) centre to generate a one-dimensional zigzag chain. In addition, the complex 1 extends to a two-dimensional supramolecular architecture through π–π stacking and hydrogen bonds. The complex shows fluorescence at ambient temperature.

A dihydrogen phosphate anionic network as a host lattice for cations in 1-methylpiperazine-1,4-diium bis(dihydrogen phosphate) and 2-(pyridin-2-yl)pyridinium dihydrogen phosphate-orthophosphoric acid (1/1).

In the salt 1-methylpiperazine-1,4-diium bis(dihydrogen phosphate), C5H13N2(2+)·2H2PO4(-), (I), and the solvated salt 2-(pyridin-2-yl)pyridinium dihydrogen phosphate-orthophosphoric acid (1/1), C10H9N2(+)·H2PO4(-)·H3PO4, (II), the formation of O-H...O and N-H...O hydrogen bonds between the dihydrogen phosphate (H2PO4(-)) anions and the cations constructs a three- and two-dimensional anionic-cationic network, respectively. In (I), the self-assembly of H2PO4(-) anions forms a two-dimensional pseudo-honeycomb-like supramolecular architecture along the (010) plane. 1-Methylpiperazine-1,4-diium cations are trapped between the (010) anionic layers through three N-H...O hydrogen bonds. In solvated salt (II), the self-assembly of H2PO4(-) anions forms a two-dimensional supramolecular architecture with open channels projecting along the [001] direction. The 2-(pyridin-2-yl)pyridinium cations are trapped between the open channels by N-H...O and C-H...O hydrogen bonds. From a study of previously reported structures, dihydrogen phosphate anions show a supramolecular flexibility depending on the nature of the cations. The dihydrogen phosphate anion may be suitable for the design of the host lattice for host-guest supramolecular systems.

A one-dimensional cobalt(II) coordination polymer based on 2,4'-oxydibenzoic acid: poly[[[diaquabis[2-(4-carboxyphenoxy)benzoato-κO(1)]cobalt(II)]-μ-4,4'-bipyridine-κ(2)N:N'] dihydrate

The reaction of CoSO4 with 2,4-oxydibenzoic acid (H2oba) and 4,4'-bipyridine (bipy) under hydrothermal condition yielded a new one-dimensional cobalt(II) coordination polymer, {[Co(C14H9O5)2(C10H8N2)(H2O)2]·2H2O}n, which was characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, magnetic properties and single-crystal X-ray diffraction. The Co(II) ions are connected by bipy ligands into infinite one-dimensional chains. The Hoba(-) ligands extend out from the two sides of the one-dimensional chain. O-H···O hydrogen bonding extends these chains into a two-dimensional supramolecular architecture.