scholarly journals A new co-crystal dinuclear/trinuclear ZnII–ZnII/ZnII–SmIII–ZnII complex with a salen-type Schiff base ligand

2018 ◽  
Vol 74 (12) ◽  
pp. 1862-1866
Author(s):  
Mamour Sarr ◽  
Mayoro Diop ◽  
Elhadj Ibrahima Thiam ◽  
Mohamed Gaye ◽  
Aliou Hamady Barry ◽  
...  
Keyword(s):  
Nitrogen Atom ◽  
Electrostatic Interactions ◽  
Solvent Molecule ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Tetrahedral Geometry ◽  
Pyramidal Geometry ◽  
Dinuclear Unit ◽  
Square Pyramidal Geometry ◽  
Oxygen Atoms

In the pentanuclear title complex, [SmZn2(C22H18N2O4)2(NCS)2(C3H7NO)2][Zn2(C22H18N2O4)(NCS)3]·C3H7NO·0.32H2O, namely bis{μ2-6,6′-dimethoxy-2,2′-[phenylene-1,2-diylbis(nitrilomethanylylidene)]diphenolato}-1κ4 O,N,N′,O′:2κ3 O,O′,O 6;2κ3 O,O′,O 6:3κ4 O,N,N′,O′-bis(dimethylformamide-2κO)dithiocyanato-1κN,3κN-2-samarium(III)-1,3-dizinc(II) {μ2-6,6′-dimethoxy-2,2′-[phenylene-1,2-diylbis(nitrilomethanylylidene)]diphenolato-1κ4 O,N,N′,O′:2κ2 O,O′}trithiocyanato-1κN;2κ2 N,N-dizinc(II) dimethylformamide monosolvate 1.32-hydrate, a dinuclear unit and a trinuclear unit co-exist. One of the ZnII centers in the dinuclear unit as well as the two ZnII centers in the trinuclear unit are located in the inner N2O2 cavity of the ligand and are coordinated to the nitrogen atom of one thiocyanate moiety, giving rise to a square-pyramidal geometry. The second ZnII center in the dinuclear unit is coordinated to the two phenolate oxygen atoms of the ligand and to two thiocyanate groups via the nitrogen atom in a tetrahedral geometry. The SmIII ion is eight-coordinated by four phenolate O atoms from the two ligand molecules, two methoxy O atoms from the two ligand molecules and two O atoms from the DFM solvent molecule. In the dinuclear unit, the two methoxy oxygen atoms remain uncoordinated while in the trinuclear unit, for each ligand one methoxy oxygen is coordinated and the other one remains uncoordinated. In the crystal, the trinuclear cationic units and dinuclear anionic units are assembled into infinite layers. These layers are held together via electrostatic interactions, forming a three-dimensional structure. In the dinuclear unit, the C and S atoms of one of the thiocyanate groups are disordered over two sets of sites in a 0.680 (4)(4):0.320 (4) ratio.

scholarly journals Syntheses and crystal structures of a new pyrazine dicarboxamide ligand, N 2,N 3-bis(quinolin-8-yl)pyrazine-2,3-dicarboxamide, and of a copper perchlorate binuclear complex

2020 ◽  
Vol 76 (3) ◽  
pp. 332-338
Author(s):  
Dilovan S. Cati ◽  
Helen Stoeckli-Evans
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Copper Atom ◽  
Binuclear Complex ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Three Dimensional Structure ◽  
Pyramidal Geometry ◽  
Difference Fourier ◽  
Square Pyramidal Geometry

The title pyrazine dicarboxamide ligand, N 2,N 3-bis(quinolin-8-yl)pyrazine-2,3-dicarboxamide (H2L1), C24H16N6O2, has a twisted conformation with the outer quinoline groups being inclined to the central pyrazine ring by 9.00 (6) and 78.67 (5)°, and by 79.94 (4)° to each other. In the crystal, molecules are linked by C—H...O hydrogen bonds, forming layers parallel to the (10\overline{1}) plane, which are in turn linked by offset π–π interactions [intercentroid distances 3.4779 (9) and 3.6526 (8) Å], forming a supramolecular three-dimensional structure. Reaction of the ligand H2L1 with Cu(ClO4)2 in acetonitrile leads to the formation of the binuclear complex, [μ-(3-{hydroxy[(quinolin-8-yl)imino]methyl}pyrazin-2-yl)[(quinolin-8-yl)imino]methanolato]bis[diacetonitrilecopper(II)] tris(perchlorate) acetonitrile disolvate, [Cu2(C24H15N6O2)(CH3CN)4](ClO4)3·2CH3CN or [Cu2(HL1−)(CH3CN)4](ClO4)3·2CH3CN (I). In the cation of complex I, the ligand coordinates to the copper(II) atoms in a bis-tridentate fashion. A resonance-assisted O—H...O hydrogen bond is present in the ligand; the position of this H atom was located in a difference-Fourier map. Both copper(II) atoms are fivefold coordinate, being ligated by three N atoms of the ligand and by the N atoms of two acetonitrile molecules. The first copper atom has a perfect square-pyramidal geometry while the second copper atom has a distorted shape. In the crystal, the cation and perchlorate anions are linked by a number of C—H...O hydrogen bonds, forming a supramolecular three-dimensional structure.

A hydrostable and twofold interpenetrating three-dimensional zinc–organic framework with rob topology based on 4,4′-oxydibenzoate and 3,3′-dimethyl-4,4′-bipyridine ligands

2016 ◽  
Vol 72 (5) ◽  
pp. 373-378 ◽  
Author(s):  
Feng-Lan Liang ◽  
De-Yun Ma ◽  
Liang Qin
Keyword(s):  
Title Compound ◽  
Three Dimensional ◽  
New Class ◽  
Pyramidal Geometry ◽  
Potential Applications ◽  
Metal Organic ◽  
Ph Range ◽  
Square Pyramidal Geometry ◽  
Bright Blue Fluorescence ◽  
Bright Blue

Metal–organic frameworks (MOFs) are a new class of porous materials that have received widespread attention due to their potential applications in gas storage and/or separation, catalysis, luminescence, and so on. The title compound, poly[[(μ2-3,3′-dimethyl-4,4′-bipyridine-κ2N:N′)bis(μ4-4,4′-oxydibenzoato-κ4O:O′:O′′:O′′′)dizinc] tetrahydrate], {[Zn2(C14H8O5)2(C12H12N2)]·4H2O}n, has been prepared by the solvothermal assembly of Zn(NO3)2·6H2O, 4,4′-oxydi(benzoic acid) and 3,3′-dimethyl-4,4′-bipyridine. The two ZnIIatoms adopt the same five-coordinated distorted square-pyramidal geometry (i.e.ZnO4N), bonding to four O atoms from four different 4,4′-oxydibenzoate (oba) ligands and one N atom from a 3,3′-dimethyl-4,4′-bipyridine (dmbpy) ligand. The supramolecular secondary building unit (SBU) is a paddle-wheel [Zn2(COO)4] unit and these units are linked by oba ligands within the layer to form a two-dimensional net parallel to thebaxis, with the dmbpy ligands pointing alternately up and down, which is further extended by dmbpy ligands to form a three-dimensional framework withrobtopology. The single net leaves voids that are filled by mutual interpenetration of an independent equivalent framework in a twofold interpenetrating architecture. The title compound shows thermal stability up to 673 K and is stable in aqueous solutions in the pH range 5–9. Excitation and luminescence data observed at room temperature show that it emits a bright-blue fluorescence.

scholarly journals Crystal structure ofL-tryptophan–fumaric acid–water (1/1/1)

2015 ◽  
Vol 71 (9) ◽  
pp. o661-o662 ◽  
Author(s):  
M. Lydia Caroline ◽  
S. Kumaresan ◽  
P. G. Aravindan ◽  
M. Peer Mohamed ◽  
G. Mani
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Fumaric Acid ◽  
Solvent Molecule ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Acid Molecule ◽  
Water Solvent ◽  
Compound C ◽  
Tryptophan Molecule

In the title compound, C11H12N2O2·C4H4O4·H2O, the L-tryptophan molecule crystallized as a zwitterion, together with a neutral fumaric acid molecule and a water solvent molecule. In the crystal, the three components are linked by a series of N—H...O, O—H...O and C—H...O hydrogen bonds, forming slabs lying parallel to (001). The slabs are connected by O—H...O hydrogen bonds, involving inversion-related fumaric acid groups, leading to the formation of a three-dimensional structure.

Understanding Bacterial Ice Nucleation

2021 ◽  
Author(s):  
Ralph Schwidetzky ◽  
Max Lukas ◽  
Anna T. Kunert ◽  
Ulrich Pöschl ◽  
Janine Fröhlich-Nowoisky ◽  
...  
Keyword(s):  
Electrostatic Interactions ◽  
Affinity Purification ◽  
Hydration Shell ◽  
Three Dimensional ◽  
American Chemical Society ◽  
Chemical Society ◽  
Ice Nucleation ◽  
Dimensional Structure ◽  
Protein Activity ◽  
Ice Nucleators

<p>Bacterial ice-nucleating proteins (INPs) promote heterogeneous ice nucleation better than any known material. On the molecular scale, bacterial INPs are believed to function by organizing water into ice‑like patterns to enable the formation of embryonic crystals. However, the details of their working mechanism remains largely elusive. Here, we report the results of comprehensive evaluations of environmentally relevant effects such as changes in pH, the presence of ions and temperature on the activity, three-dimensional structure and hydration shell of bacterial ice nucleators using ice affinity purification, high-throughput ice nucleation assays and surface-specific sum-frequency generation spectroscopy.</p><p> </p><p>[1] Lukas, Max, et al. "Electrostatic Interactions Control the Functionality of Bacterial Ice Nucleators." Journal of the American Chemical Society 142.15 (2020): 6842-6846.</p><p>[2] Lukas, Max, et al. "Interfacial Water Ordering Is Insufficient to Explain Ice-Nucleating Protein Activity." The Journal of Physical Chemistry Letters 12 (2020): 218-223.</p>

Synthesis of Dendridic NLO Chromophores for the Improvement of Order in Electro-optics

2004 ◽  
Vol 846 ◽  
Author(s):  
Jessica Sinness ◽  
Olivier Clot ◽  
Scott R. Hammond ◽  
Nishant Bhatambrekar ◽  
Harrison L. Rommel ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Electrostatic Interactions ◽  
Dipole Moments ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Quantum Calculations ◽  
Electro Optic ◽  
The Matrix ◽  
Macroscopic Domain ◽  
Nlo Chromophores

ABSTRACTPrevious research in organic electro-optics has shown dramatic increases in the hyperpolarizablity of NLO chromophores. However, this large microscopic activity has not been translated to the macroscopic domain. The polymeric electro-optic (E-O) materials continue to lack the high noncentrosymmetric order of the poled chromophores within the matrix necessary for high E-O response (r33). This deficiency of order represents one major obstacle that must be overcome before E-O device commercialization can be achieved. This lack of order is partially due to the large dipole moments of high μβ chromophores, which cause the chromophores to align in a centrosymmetric fashion through intermolecular electrostatic interactions. However, quantum calculations show that when the aspect ratio between the width and length of the chromophore system is adjusted to be greater than 1.4:1 by adding bulky side groups around the center of the chromophore, it would prevent side on pairing of the chromophores. This would cause a decrease in the large areas of centrosymmetric aggregation and thus allow for easier poling of the system. Here we report the synthesis of a nanoscale NLO architecture in which dendritic moieties have been incorporated around the center of the chromophore to give a three dimensional structure in order to achieve the 1.4:1 aspect ratio and maximize the macroscopic order of the system.

Assembly states of the nucleosome assembly protein 1 (NAP-1) revealed by sedimentation velocity and non-denaturing MS

2011 ◽  
Vol 436 (1) ◽  
pp. 101-112 ◽  
Author(s):  
Masanori Noda ◽  
Susumu Uchiyama ◽  
Adam R. McKay ◽  
Akihiro Morimoto ◽  
Shigeki Misawa ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Electrostatic Interactions ◽  
Analytical Ultracentrifugation ◽  
Three Dimensional ◽  
Sedimentation Velocity ◽  
Dimensional Structure ◽  
Histone H2a ◽  
Nucleosome Assembly ◽  
Nucleosome Assembly Protein ◽  
Nucleosome Assembly Protein 1

Proteins often exist as ensembles of interconverting states in solution which are often difficult to quantify. In the present manuscript we show that the combination of MS under nondenaturing conditions and AUC-SV (analytical ultracentrifugation sedimentation velocity) unambiguously clarifies a distribution of states and hydrodynamic shapes of assembled oligomers for the NAP-1 (nucleosome assembly protein 1). MS established the number of associated units, which was utilized as input for the numerical analysis of AUC-SV profiles. The AUC-SV analysis revealed that less than 1% of NAP-1 monomer exists at the micromolar concentration range and that the basic assembly unit consists of dimers of yeast or human NAP-1. These dimers interact non-covalently to form even-numbered higher-assembly states, such as tetramers, hexamers, octamers and decamers. MS and AUC-SV consistently showed that the formation of the higher oligomers was suppressed with increasing ionic strength, implicating electrostatic interactions in the formation of higher oligomers. The hydrodynamic shapes of the NAP-1 tetramer estimated from AUC-SV agreed with the previously proposed assembly models built using the known three-dimensional structure of yeast NAP-1. Those of the hexamer and octamer could be represented by new models shown in the present study. Additionally, MS was used to measure the stoichiometry of the interaction between the human NAP-1 dimer and the histone H2A–H2B dimer or H3–H4 tetramer. The present study illustrates a rigorous procedure for the analysis of protein assembly and protein–protein interactions in solution.

scholarly journals Tetraaquabis(N,N-dimethylformamide-κO)zinc(II) bis[(2-{3-[2-(carboxylatomethoxy-κ2 O,O′)phenyl]pyrazol-1-yl-κN 2}acetato-κO)chloridozincate(II)]

2012 ◽  
Vol 68 (6) ◽  
pp. m817-m817
Author(s):  
Jie Yang ◽  
Lei Shen ◽  
Cheng Ji ◽  
Xiao-Feng Shen ◽  
Gao-Weng Yang
Keyword(s):  
Three Dimensional ◽  
Dimensional Structure ◽  
Distorted Octahedral Geometry ◽  
Inversion Center ◽  
Asymmetric Unit ◽  
Pyramidal Geometry ◽  
Acetate Ligand ◽  
Dimensional Network ◽  
Distorted Octahedral ◽  
Cl Atom

The asymmetric unit of the title compound, [Zn(C3H7NO)2(H2O)4][Zn(C13H10N2O5)Cl]2, is composed of a single anion and half a cation. The ZnII atom in the monoanion has a distorted triganol–pyramidal geometry, being coordinated by three O atoms and one N atom from one 2-{3-[2-(carboxylatomethoxy)phenyl]pyrazol-1-yl}acetate ligand and one Cl atom. In the dication, the ZnII atom is located on an inversion center and is coordinated by six O atoms in a slightly distorted octahedral geometry. In the crystal, the ions are linked by O—H...O hydrogen bonds, forming a two-dimensional network lying parallel to the ab plane. There are also C—H...O and C—H...Cl interactions present, which lead to the formation of a three-dimensional structure.

Preparation and X-Ray Structure of 4-N,N′-Bis(trimethylsilyl)- amino-3,5-diisopropylphenylselenium Trichloride

1999 ◽  
Vol 54 (9) ◽  
pp. 1170-1174 ◽  
Author(s):  
Arto Maaninen ◽  
René T. Boeré ◽  
Tristram Chivers ◽  
Masood Parvez
Keyword(s):  
Nitrogen Atom ◽  
Phenyl Ring ◽  
Electrophilic Aromatic Substitution ◽  
Aromatic Substitution ◽  
Space Group ◽  
X Ray ◽  
Triclinic System ◽  
Pyramidal Geometry ◽  
Square Pyramidal Geometry

The reaction of SeCl4 or SeCl2 with N,N′-bis(trimethylsilyl)-2,6-diisopropylaniline occurs not at the nitrogen atom but by electrophilic aromatic substitution at C-4 of the phenyl ring to give [(CH3)3Si]2NC6H2 (iPr2)SeCl3 , which crystallizes as the chloro-bridged dimer in the triclinic system, space group P1̅, a - 10.2598(17), b = 13.665(3), c = 9.7838(10) Å, a = 90.056(13), ß = 102.439(11), γ = 70.922(14)°, V = 1262.3(4) Å3, Z= 1. The dimer contains an essentially planar Cl2Se(μ-Cl)2SeCl2 unit, with trans apical (Me3Si)2NC6H2(iPr)2 groups, resulting in approximately square pyramidal geometry at Se. The bridging Se-Cl distances are unequal at 2.587(2) and 2.749(2) Å.

[2,5-Bis(2,2′-bipyridyl-6-yl)-3,4-diazahexa-2,4-diene]dichloridomanganese(II): from a mononuclear compound to a three-dimensional supramolecular framework through C—H...Cl hydrogen bonds and π–π stacking interactions

2014 ◽  
Vol 70 (7) ◽  
pp. 718-721
Author(s):  
Zhengliang Lu ◽  
Yuanchao Zhao ◽  
Baolian Chen ◽  
Ximing Huang ◽  
Chunhua Fan
Keyword(s):  
Hydrogen Bonds ◽  
Three Dimensional ◽  
Stacking Interactions ◽  
Dimensional Chain ◽  
Supramolecular Framework ◽  
One Dimensional ◽  
Pyramidal Geometry ◽  
Π Stacking ◽  
Square Pyramidal Geometry ◽  
Multifunctional Ligand

The title compound, [MnCl2(C24H20N6)], has been synthesized and characterized based on the multifunctional ligand 2,5-bis(2,2′-bipyridyl-6-yl)-3,4-diazahexa-2,4-diene (L). The MnIIcentre is five-coordinate with an approximately square-pyramidal geometry. TheLligand acts as a tridendate chelating ligand. The mononuclear molecules are bridged into a one-dimensional chain by two C—H...Cl hydrogen bonds. These chains are assembled into a two-dimensional layer through π–π stacking interactions between adjacent uncoordinated bipyridyl groups. Furthermore, a three-dimensional supramolecular framework is attained through π–π stacking interactions between adjacent coordinated bipyridyl groups.

Aromatic interactions in proteins, DNA and synthetic receptors

1993 ◽  
Vol 345 (1674) ◽  
pp. 77-85 ◽  
Keyword(s):  
Electrostatic Interactions ◽  
Three Dimensional ◽  
Interaction Model ◽  
Dimensional Structure ◽  
Π Interactions ◽  
Aromatic Stacking ◽  
Dna Base ◽  
Conformational Preferences ◽  
Out Of Plane ◽  
Dna Base Pair

Non-covalent interactions between aromatic molecules (π-π interactions) play a major role in biological molecular recognition. A simple theoretical model which accounts for the geometric properties of π-π interactions is described. The key feature of this model is that it specifically allows for out-of-plane π-electron density in the calculation of electrostatic interactions. Experimental evidence for the validity of the model comes from studies of the geometric distribution of phenylalanine-phenylalanine interactions in protein X-ray crystal structures. The model has also been used to design a synthetic molecular receptor which recognizes p -benzoquinone using H-bonds and edge-to-face π-π interactions. Aromatic stacking interactions provide the crucial link between sequence and three-dimensional structure in double-helical DNA. The π-π interaction model has been used to calculate the conformational preferences of all ten DNA base-pair steps and the results provide new insight into the molecular basis of sequence-dependent DNA structure.

Sign in / Sign up

Export Citation Format

Share Document