Search results for "Supramolecular"
showing 10 items of 830 documents
Columnar supramolecular architecture of crystals of 2-(4-Iodophenyl)-1,10-phenanthroline derived from values of intermolecular interaction energy
2011
Using results of X-ray diffraction study supramolecular architecture of crystals of 2-(4-iodophenyl)-1,10-phenanthroline has been analyzed on the basis of quantum-chemical calculations of intermolecular interactions energy. It is demonstrated that these crystals have three levels of organization. Molecules form stacked dimers with the highest binding energy (first level). These dimers represent basic unit of infinite columns stabilized by stacking interactions between dimers (second level). The energy of intermolecular interactions between neighbouring stacked columns is very close. This does not allow to figure out any layers in the crystal. Therefore crystals of this compound have columna…
Unexpected magnetic topology in the heterobimetallic [ReIVBr4(μ-ox)CuII(bpy)2] compound
2011
Abstract A novel oxalato-bridged rhenium(IV)-copper(II) compound, namely [ReIVBr4(μ-ox)CuII(bpy)2] (1), has been obtained by reacting (PPh4)2[ReBr4(ox)] with Cu(CF3SO3)2 and 2,2′-bpy in CH3CN, and its crystal structure determined by single-crystal X-ray diffraction. Intermolecular Br⋯Br interactions and nonbonding Cu⋯Br type contacts between the heterobimetallic dinuclear units lead to a two-dimensional supramolecular structure. Compound 1 behaves magnetically as a [ReIVCuII]2 tetranuclear species with weak antiferromagnetic interactions through the oxalato bridge and intermolecular Br⋯Br contacts.
Intermolecular interactions in dictating the self-assembly of halogen derivatives of bis-(N-substituted oxamato)palladate(ii) complexes
2016
Three palladium(II) complexes of formula (n-Bu4N)2[Pd(4-Fpma)2] (1), (n-Bu4N)2[Pd(4-Clpma)2]·4H2O (2) and (n-Bu4N)2[Pd(4-Brpma)2]·4H2O (3) [n-Bu4N+ = tetra-n-butylammonium cation, 4-Fpma = N-4-fluorophenyloxamate, 4-Clpma = N-4-chlorophenyloxamate and 4-Brpma = N-4-bromophenyloxamate] have been prepared and their structures determined by single crystal X-ray diffraction. Each palladium(II) ion in 1–3 is four-coordinate with two oxygen and two nitrogen atoms from two fully deprotonated oxamate ligands building PdO2N2 square planar surroundings, the oxamate ligands exhibiting trans (1 and 2) and cis (3) dispositions. The fluoro substituent and the organic counterion in 1 are involved in C–H⋯F…
Selective Formation of S4- and T-Symmetric Supramolecular Tetrahedral Cages and Helicates in Polar Media Assembled via Cooperative Action of Coordina…
2020
We report on the synthesis and self-assembly study of novel supramolecular monomers encompassing quadruple hydrogen-bonding motifs and metal-coordinating 2,2'-bipyridine units. When mixed with metal ions such as Fe2+ or Zn2+, the tetrahedron cage complexes are formed in quantitative yields and full diastereoselectivity, even in highly polar acetonitrile or methanol solvents. The symmetry of the complexes obtained has been shown to depend critically on the flexibility of the ligand. Restriction of the rotation of the hydrogen-bonding unit with respect to the metal-coordinating site results in a T-symmetric cage, whereas introducing flexibility either through a methylene linker or rotating be…
Organotin(IV) trifluoromethanesulfonates chemistry: Isolation and characterization of a new di-n-butyl derivative presenting a Sn3O3 core
2012
Abstract Reaction of the dimeric hydroxo di-n-butylstannane trifluoromethanesulfonato complex [n-Bu2Sn(OH)(H2O)(CF3SO3)]2 (1) with a mixture of anthracene (C14H10, Ant) and phenazine (C12H8N2, Phz) in dichloromethane at room temperature yielded the novel di-n-butyltin(IV) trifluoromethanesulfonate salt {[n-Bu2Sn(H2O)]2O·n-Bu2Sn(OH)2}(CF3SO3)2 (2), together with the co-crystallization of phenazinium trifluoromethanesulfonate salts ([C12H9N2][CF3SO3], PhzH) collected in the solid state in two distinct self-assembled architectures, 3 and 4, showing π–π stacking interactions, and involving the intercalation of free molecules of phenazine and anthracene, respectively. Complex 2 is a cationic tri…
"Comment on ""Non-symmetric substituted ureas locked in an (E,Z) conformation: an unusual anion binding via supramolecular assembly"" by M. Olivari, …
2014
We propose another point of view on the type of hydrogen bonded complexes that were described in this journal (M. Olivari et al., New J. Chem., 2013, 37, 663). The main difference is the molecular geometry and breakage of the intramolecular hydrogen bond during association. The current comment is to highlight mentioned aspects and to point out that in some cases the interpretation may not be straightforward due to the simultaneous effects associated with complexation.
Self-assembly mechanism of nanoparticles of Ni-based Prussian Blue analogues at the air/liquid interface: a synchrotron X-ray reflectivity study.
2015
Prussian Blue analogue (PBA) nanoparticles can be self-assembled at air/liquid interfaces to build novel materials with interesting magnetic features. Herein, we study the influence of the size of PBA Cs0.4 Ni[Cr(CN)6 ]0.9 and K0.25 Ni[Fe(CN)6 ]0.75 nanoparticles on the self-assembly behavior by synchrotron X-ray reflectivity. Both nanoparticles show similar Z-potential values. The phospholipid dipalmitoylphosphatidylcholine and the amino surfactant dimethyldioctadecylammonium have been used as Langmuir monolayers to anchor the PBA nanoparticles and study the interplay of forces directing the self-assembly of the nanoparticles at the surfactant/liquid interface. Whereas Cs0.4 Ni[Cr(CN)6 ]0.…
Communication between iron(II) building blocks in cooperative spin transition phenomena
2003
[EN] In the present article we discuss the cooperative nature of the spin crossover phenomenon in iron(II) complexes, providing a perspective of the state of the art in this area. The first aspect we discuss is the role of the intermolecular interactions, more precisely the ¿-interactions, in mononuclear complexes. We show that by playing with the nature of the ligands, aliphatic, aromatic, or extended aromatic, it is possible to create stronger cohesive forces and receive a more cooperative response from the compound. In the next step the singular family of bipyrimidine-bridged iron(II) dinuclear compounds is presented as the simplest example of polynuclear spin crossover complexes exhibit…
Functionalization of Graphene with Molecules and/or Nanoparticles for Advanced Applications
2019
Graphene is considered the material of the third millennium, due to its extraordinary electronic and mechanical properties, and due to the possibility to modulate its conductivity, flexibility, elasticity, transparency, and biocompatibility by bottom-up approach. The possibility to gather the proper- ties of graphene and graphene oxide with those of functional moieties or nanoparticles is herein reviewed. The synthetic approaches proposed, either covalent or noncovalent, are aimed to tune appropriately graphene’s properties for the realization of materials for advanced uses, such as bio- medical applications, sensors, catalysis, and energy devices. In particular, methods based on covalent l…
Interaction of aminomethylated resorcinarenes with rhodamine B
2009
The interaction of aminomethylated resorcinarenes with a red xanthene dye, rhodamine B, was investigated in chloroform, methanol and chloroform–methanol solutions using UV-vis, NMR and fluorescence spectroscopy. Aminomethylated resorcinarenes 1 and 2 shift the rhodamine B equilibrium from the zwitterion to the lactone form unlike reference compounds 3 and 4, which do not contain tertiary amino groups at the upper rim, giving an example of how supramolecular hosts can influence the equilibrium of rhodamine B isomers.