On-Surface Assembly of Hydrogen- and Halogen-Bonded Supramolecular Graphyne-Like Networks

Demonstrated here is a supramolecular approach to fabricate highly ordered monolayered hydrogen- and halogen-bonded graphyne-like two-dimensional (2D) materials from triethynyltriazine derivatives on Au(111) and Ag(111). The 2D networks are stabilized by N⋅⋅⋅H−C(sp) bonds and N⋅⋅⋅Br−C(sp) bonds to the triazine core. The structural properties and the binding energies of the supramolecular graphynes have been investigated by scanning tunneling microscopy in combination with density-functional theory calculations. It is revealed that the N⋅⋅⋅Br−C(sp) bonds lead to significantly stronger bonded networks compared to the hydrogen-bonded networks. A systematic analysis of the binding energies of triethynyltriazine and triethynylbenzene derivatives further demonstrates that the X₃-synthon, which is commonly observed for bromobenzene derivatives, is weaker than the X₆-synthon for our bromotriethynyl derivatives.     

On‐Surface Assembly of Hydrogen‐ and Halogen‐Bonded Supramolecular Graphyne‐Like Networks

Demonstrated here is a supramolecular approach to fabricate highly ordered monolayered hydrogen‐ and halogen‐bonded graphyne‐like two‐dimensional (2D) materials from triethynyltriazine derivatives on Au(111) and Ag(111). The 2D networks are stabilized by N???H?C(sp) bonds and N???Br?C(sp) bonds to the triazine core. The structural properties and the binding energies of the supramolecular graphynes have been investigated by scanning tunneling microscopy in combination with density‐functional theory calculations. It is revealed that the N???Br?C(sp) bonds lead to significantly stronger bonded networks compared to the hydrogen‐bonded networks. A systematic analysis of the binding energies of triethynyltriazine and triethynylbenzene derivatives further demonstrates that the X₃‐synthon, which is commonly observed for bromobenzene derivatives, is weaker than the X₆‐synthon for our bromotriethynyl derivatives.     

Supramolecular Assembly of Metal Complexes by (Aryl)I⋅⋅⋅d [PtII] Halogen Bonds

The theoretical data for the half-lantern complexes [{Pt( )(μ- )}₂] [ 1 – 3 ; is cyclometalated 2-Ph-benzothiazole; is 2-SH-pyridine ( 1 ), 2-SH-benzoxazole ( 2 ), 2-SH-tetrafluorobenzothiazole ( 3 )] indicate that the Pt ⋅⋅⋅ Pt orbital interaction increases the nucleophilicity of the outer d orbitals to provide assembly with electrophilic species. Complexes 1 – 3 were co-crystallized with bifunctional halogen bonding (XB) donors to give adducts ( 1 – 3 )₂ ⋅ (1,4-diiodotetrafluorobenzene) and infinite polymeric [ 1⋅ 1,1′-diiodoperfluorodiphenyl]_n. X-ray crystallography revealed that the supramolecular assembly is achieved through (Aryl)I ⋅⋅⋅ d [Pt^II] XBs between iodine σ-holes and lone pairs of the positively charged (Pt^II)₂ centers acting as nucleophilic sites. The polymer includes a curved linear chain ⋅⋅⋅ Pt₂ ⋅⋅⋅ I(arene^F)I ⋅⋅⋅ Pt₂ ⋅⋅⋅ involving XB between iodine atoms of the perfluoroarene linkers and (Pt^II)₂ moieties. The ¹⁹⁵Pt NMR, UV/Vis, and CV studies indicate that XB is preserved in CH(D)₂Cl₂ solutions.     

Influence of intermolecular interactions on the formation of tetra(carbomethoxy)-tetrathiafulvalene assemblies.

We study the assemblies that tetra(carbomethoxy)tetrathiafulvalene (TCM-TTF) forms in solution and when deposited on a surface depending on intermolecular interactions and on the interactions with the substrate and the solvent. Its organization on graphite and mica substrates was studied by atomic force microscopy, and different molecular assemblies were observed depending on the prevailing interactions. The promotion of molecule-molecule interactions gave rise to the formation of molecular fibers. The investigation of the influence of the solvent-molecule interactions on TCM-TTF molecular organizations was carried out by UV/Vis spectroscopy, and a new TCM-TTF polymorph was obtained by changing the nature of the solvent. Finally, an explanation for all these phenomena, supported by computational modeling, is put forward.     

Structure-defining interactions in the salt cocrystals of [(Me5C5)2Fe]+I3−–XC6H4OH (X = Cl,I): weak noncovalent vs. strong ionic bonding

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Self-Assembly of Coordinative Supramolecular Polygons with Open Binding Sites

The design and synthesis of coordinative supramolecular polygons with open binding sites is described. Coordination-driven self-assembly of 2,6-bis(pyridin-4-ylethynyl)pyridine with 60° and 120° organoplatinum acceptors results in quantitative formation of a supramolecular rhomboid and hexagon, respectively, both bearing open pyridyl binding sites. The structures were determined by multinuclear (³¹P and ¹H) NMR spectroscopy and electrospray ionization (ESI) mass spectrometry, along with a computational study.     

Hydrogen Bonded 3D Molecular Self Assembly Constructed from [(Ni(nicotinamide)2(thiocyanate)2(H2O)2] Complex Showing Spin Canted Anti-ferromagnetic Character

A new three-dimensional nickel(Ⅱ) hydrogen-bonded molecular self assembly containing [(Ni(nicotinamide)2(thiocyanate)2(H2O)2] complex has been synthesized and characterized by single-crystal X-ray diffraction,FTIR spectroscopy,thermal analysis and magnetic measurements.Structural analysis reveals that the complex crystallizes in triclinic space group P1(crystal data a = 7.5574,b = 8.2683,c = 9.0056 ?,α = 73.010,β = 69.698,γ = 66.51) and exhibits a distorted octahedral coordination sphere.Most interesting point in its structure is the involvement of sulphur atom of thiocyanate moiety in the trifurcated hydrogen bonding to build up the hydrogen-bonded self assembly.The magnetic behavior as determined by squid magnetometer(2~300 K temp.range) reveals dominating antiferromagnetic interaction followed by spin canting behavior below 20 K.     

Supramolecular Assembly of a Molecularly Engineered Protein and Polymer

Programmable assembly of biomolecules is a fast growing research area that aims to emulate nature's elegance in creating numerous hierarchical self-assembled structures, which are responsible for unimaginably difficult biological functions. Protein assembly is a particularly challenging task, owing to their structural diversity, conformational heterogeneity, and high molecular weight. This article reveals the ability of a supramolecular structure-directing unit (SSDU) to regulate the entropically favourable supramolecular assembly of a covalently conjugated protein (bovine serum albumin (BSA)) to produce well-defined protein-decorated micelles with remarkably high thermal stability, suppression of the thermal denaturation of the protein, and retention of enzymatic activity. Furthermore, a SSDU-appended thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) co-assembles with the SSDU–BSA conjugate because, in both cases, assembly was primarily driven by specific molecular recognition between the SSDUs. However, the resulting supramolecular protein–polymer conjugate exhibits distinctly different polymersome structure to that of the micellar particle produced by the protein-SSDU conjugate. In this case, the enzymatic activity can be significantly suppressed above the lower critical solution temperature of supramolecularly conjugated PNIPAM, possibly due to collapse of the de-solvated polymer chains on the protein surface.     

Rational Modification of the Hierarchy of Intermolecular Interactions in Molecular Crystal Structures by Using Tunable Halogen Bonds

A family of 16 isomolecular salts (3‐XpyH)₂[MX′₄] (3‐XpyH=3‐halopyridinium; M=Co, Zn; X=(F), Cl, Br, (I); X′=Cl, Br, I) each containing rigid organic cations and tetrahedral halometallate anions has been prepared and characterized by X‐ray single crystal and/or powder diffraction. Their crystal structures reflect the competition and cooperation between non‐covalent interactions: N? H???X′? M hydrogen bonds, C? X???X′? M halogen bonds and π–π stacking. The latter are essentially unchanged in strength across the series, but both halogen bonds and hydrogen bonds are modified in strength upon changing the halogens involved. Changing the organic halogen (X) from F to I strengthens the C? X???X′? M halogen bonds, whereas an analogous change of the inorganic halogen (X′) weakens both halogen bonds and N? H???X′? M hydrogen bonds. By so tuning the strength of the putative halogen bonds from repulsive to weak to moderately strong attractive interactions, the hierarchy of the interactions has been modified rationally leading to systematic changes in crystal packing. Three classes of crystal structure are obtained. In type A (C? F???X′? M) halogen bonds are absent. The structure is directed by N? H???X′? M hydrogen bonds and π‐stacking interactions. In type B structures, involving small organic halogens (X) and large inorganic halogens (X′), long (weak) C? X???X′? M interactions are observed with type I halogen–halogen interaction geometries (C? X???X′ ≈ X???X′? M ≈155°), but hydrogen bonds still dominate. Thus, minor but quite significant perturbations from the type A structure arise. In type C, involving larger organic halogens (X) and smaller inorganic halogens (X′), stronger halogen bonds are formed with a type II halogen–halogen interaction geometry (C? X???X′ ≈180°; X???X′? M ≈110°) that is electrostatically attractive. The halogen bonds play a major role alongside hydrogen bonds in directing the type C structures, which as a result are quite different from type A and B.     

Self‐Assembly of a Highly Organized,Hexameric Supramolecular Architecture: Formation,Structure and Properties

Two derivatives, ³ L and ⁹ L , of a ditopic, multiply hydrogen‐bonding molecule, known for more than a decade, have been found, in the solid state as well as in solvents of low polarity at room temperature, to exist not as monomers, but to undergo a remarkable self‐assembly into a complex supramolecular species. The solid‐state molecular structure of ³ L , determined by single‐crystal X‐ray crystallography, revealed that it forms a highly organized hexameric entity ³ L ₆ with a capsular shape, resulting from the interlocking of two sets of three monomolecular components, linked through hydrogen‐bonding interactions. The complicated ¹H NMR spectra observed in o‐dichlorobenzene (o‐DCB) for ³ L and ⁹ L are consistent with the presence of a hexamer of D₃ symmetry in both cases. DOSY measurements confirm the hexameric constitution in solution. In contrast, in a hydrogen‐bond‐disrupting solvent, such as DMSO, the ¹H NMR spectra are very simple and consistent with the presence of isolated monomers only. Extensive temperature‐dependent ¹H NMR studies in o‐DCB showed that the L ₆ species dissociated progressively into the monomeric unit on increasing th temperature, up to complete dissociation at about 90 °C. The coexistence of the hexamer and the monomer indicated that exchange was slow on the NMR timescale. Remarkably, no species other than hexamer and monomer were detected in the equilibrating mixtures. The relative amounts of each entity showed a reversible sigmoidal variation with temperature, indicating that the assembly proceeded with positive cooperativity. A full thermodynamic analysis has been applied to the data.     

Influence of Fluorine Substitution on Nonbonding Interactions in Selected Para-Halogeno Anilines

A series of 4-halogeno aniline derivatives was studied employing combined theoretical and experimental methods (i. e. crystal structure analysis and vibrational spectroscopies). This simplified model system was selected to shed light on the impact of fluorine substitution on the formation of noncovalent interactions such as halogen bonds (XBs) and hydrogen bonds (HBs), which are key interactions in fluorinated/halogenated drug-protein complex formation. Comparative analysis of three previously reported and five newly determined crystal structures indicated that, in most cases, 2-fluoro and 2,6-difluoro substitution of 4-X anilines increases the ability of adjacent amine to form strong N−H⋅⋅⋅N HBs. Additionally, fluorine substituents in the difluorinated derivatives are competitive and attractive HB and XB acceptors and increase the probability of halogen-halogen contacts. A peculiar observation was made for 4-iodoaniline and 2,6-difluoro-4-iodoaniline, which form distinct interaction patterns compared to the corresponding 4-Cl and 4-Br analogs. The observed intramolecular N−H⋅⋅⋅F interactions lead to additional NH bands in the FT-IR spectra.     

Concentration‐Dependent Hydrogen‐Bonding Effects on the Dimethyl Sulfoxide Vibrational Structure in the Presence of Water,Methanol, and Ethanol

The effects of hydrogen bonding between dimethyl sulfoxide (DMSO) and the co‐solvents water, methanol, and ethanol on the symmetric and antisymmetric CSC stretching vibrations of DMSO are investigated by means of Raman spectroscopy. The Raman spectra are recorded as a function of co‐solvent concentration and reflect changes in structure and polarizability as well as hydrogen‐bond donor and acceptor ability. In all cases studied a nonideal mixing behavior is observed. The spectra of the DMSO/water system show blue‐shifted CSC stretching modes. The antisymmetric frequencies are always further blue‐shifted than the symmetric stretching ones. The DMSO/methanol system also features blue‐shifted CSC stretching frequencies but at high mole fractions a pronounced red shifting is observed. In the binary DMSO/ethanol system, the co‐solvent also gives rise to blue shifts of the CSC stretching frequencies but restricted to mole fractions between x=0.38 and 0.45. The different magnitudes and occurrences of both blue‐ and red‐shifted spectral lines are comprehensively and critically discussed with respect to the existing literature concerning wavenumbers and Raman intensities in both absolute and normalized values. In particular, the normalized Raman intensities show a higher sensitivity for the nonideal mixing behavior because they are independent of the mole fraction.     

Understanding the Supramolecular Self‐Assembly of the Fullerene Derivative PCBM on Gold Surfaces

We report a DFT study on the self‐assembly of the fullerene derivative PCBM on the Au(111) surface. Recent STM experiments (Angew. Chem. 2007 , 119, 8020–8023^[1]) show a coverage‐dependent transition of the adsorption and self‐assembly of PCBM on this surface. To understand the origin of this observation, we compute the geometries and relative energies of ten PCBM dimers and four tetramers. The calculations show that the self‐assembly of PCBM at high coverage is mainly controlled by hydrogen bonding between the PCBM tails. Due to the large size of the fullerene cage, the hydrogen bonds are formed far away from the surface; hence they are very similar to those found in the gas phase. This picture successfully explains the observed site‐insensitive adsorption at high coverage and the 2D arrangement of PCBM on the surface.     

Synthesis and Crystal Structure of a Novel Three-dimensional Supramolecular Compound [（AgI3）（4-HBPFA）2（H2O）]

1 INTRODUCTION In recent years, the rational design and synthesisof metal-directed supramolecular frameworks throughintermolecular hydrogen bonds, π-π stacking interac-tion or other weak interactions have received muchattention because of their interesting molecular topo-logies and various potential applications in catalysis,superconductor, magnetism, nonlinear optics, sen-sors and molecular recognition[1～4]. On the otherhand, the attachment of mono- or polypyridyl frag-ments to a ferr…     

Synthesis and Crystal Structure of 4-Nitro-2- [（2-diethylaminoethylimino）methyl]phenol

1 INTRODUCTION Schiff base ligands have played an important role in the development of coordination chemistry as they readily form stable complexes with most metal ions[1～4]. These complexes are very interesting in many fields, such as catalysis and enzymatic reac- tions[5, 6], magnetism and molecular architectures[7～9]. The complexes derived from the similar tridentate Schiff base ligand 2-[(2-dimethylaminoethylimino)- methyl]phenol[10, 11] and its derivatives[12～14] have been widely …     

Controlling the Length of Cooperative Supramolecular Polymers with Chain Cappers

The design and the characterization of supramolecular additives to control the chain length of benzene-1,3,5-tricarboxamide (BTA) cooperative supramolecular polymers under thermodynamic equilibrium is unraveled. These additives act as chain cappers of supramolecular polymers and feature one face as reactive as the BTA discotic to interact strongly with the polymer end, whereas the other face is nonreactive and therefore impedes further polymerization. Such a design requires fine tuning of the conformational preorganization of the amides and the steric hindrance of the motif. The chain cappers studied are monotopic derivatives of BTA, modified by partial N-methylation of the amides or by positioning of a bulky cyclotriveratrylene cage on one face of the BTA unit. This study not only clarifies the interplay between structural variations and supramolecular interactions, but it also highlights the necessity to combine orthogonal characterization methods, spectroscopy and light scattering, to elucidate the structures and compositions of supramolecular systems.     

The Impact of Halogen Substituents on the Synthesis and Structure of Co-Crystals of Pyridine Amides

Strategies for co-crystal synthesis tend to employ either hydrogen- or halogen-bonds between different molecules. However, when both interactions are present, the structural influence that they may exert on the resulting assembly is difficult to predict a priori. To shed some light on this supramolecular challenge, we attempted to co-crystallize ten aliphatic dicarboxylic acids (co-formers) with three groups of target molecules; N-(pyridin-2-yl)picolinamides (2Pyr-X), N-(pyridin-2-yl)nicotinamides (3Pyr-X), N-(pyridin-2-yl)isonicotinamides (4Pyr-X); X=Cl/ Br/ I. The structural outcomes were compared with co-crystals prepared from the non-halogenated targets. As expected, none of the reactions with 2Pyr-X produced co-crystals due to the presence of a very stable intramolecular N-H···N hydrogen bond. In the 3Pyr series, all six structures obtained showed the same synthons, –COOH···N(py) and –COOH···N(py)-NH, that were found in the non-halogenated parent 3Pyr and were additionally accompanied by structure directing X···O(OH) interactions (X=Br/I). The co-crystals of the unhalogenated parent 4Pyr co-crystals assembled via intermolecular –COOH···N(py) and –COOH···N(py)-NH synthons. Three of the analogues 4Pyr-X co-crystals displayed only COOH···N(py) and –COOH···N(py)-NH interactions. The three co-crystals of 4Pyr-X with fumaric acid (for which no analogues structures with 4Pyr are known) formed –COOH···N(py)-NH and –NH···O=C hydrogen bonds and showed no structure-directing halogen bonds. In three co-crystals of 4Pyr-I in which –COOH···N(py)-NH hydrogen bond was present, a halogen-bond based –I···N(py) synthon replaced the –COOH···N(py) motif observed in the parent structures. The structural influence of the halogen atoms increased in the order of Cl < Br < I, as the size of σ-holes increased. Finally, it is noteworthy that isostructurality among structures of the homomeric targets was not translated to structural similarities between their respective co-crystals.