Search results for "Intermolecular"
showing 10 items of 396 documents
“Tail–Tail Dimerization” of Ferrocene Amino Acid Derivatives
2010
Acid anhydrides of N-protected 1'-aminoferrocene-1-carboxylic acid (Fca) have been prepared and spectroscopically characterized (protection group Boc, Fmoc, Ac; 4a―4c). The structure of the Boc-derivative 4a has been determined by single-crystal X-ray crystallography. An intramolecular N― H···O hydrogen bond involving the carbamate units results in a ring structure containing the two ferrocene units, the anhydride moiety, and the hydrogen bond. In the crystal, the individual molecules are connected by intermolecular N-H···O hydrogen bonds of the carbamate unit. Experimental and theoretical studies suggest that the ring motif is also a dominant species in solution. Electronic communication a…
Recognition of N-Alkyl- and N-Aryl-Acetamides by N-Alkyl Ammonium Resorcinarene Chlorides
2014
N-alkyl ammonium resorcinarene chlorides are stabilized by an intricate array of intra- and intermolecular hydrogen bonds that leads to cavitand-like structures. Depending on the upper-rim substituents, self-inclusion was observed in solution and in the solid state. The self-inclusion can be disrupted at higher temperatures, whereas in the presence of small guests the self-included dimers spontaneously reorganize to 1:1 host-guest complexes. These host compounds show an interesting ability to bind a series of N-alkyl acetamide guests through intermolecular hydrogen bonds involving the carbonyl oxygen (C=O) atoms and the amide (NH) groups of the guests, the chloride anions (Cl(-)) and ammoni…
Sublimable Single Ion Magnets Based on Lanthanoid Quinolinate Complexes: The Role of Intermolecular Interactions on Their Thermal Stability
2018
We report the design, preparation, and characterization of two families of thermally robust coordination complexes based on lanthanoid quinolinate compounds: [Ln(5,7-Br2q)4]− and [Ln(5,7-ClIq)4]−, where q = 8-hydroquinolinate anion and Ln = DyIII, TbIII, ErIII, and HoIII. The sodium salt of [Dy(5,7-Br2q)4]− decomposes upon sublimation, whereas the sodium salt of [Dy(5,7- ClIq)4]−, which displays subtly different crystalline interactions, is sublimable under gentle conditions. The resulting film presents low roughness with high coverage, and the molecular integrity of the coordination complex is verified through AFM, MALDI-TOF, FT-IR, and microanalysis. Crucially, the single-molecule magnet …
Polymeric alloys: Model materials for the understanding of the statistical thermodynamics of mixtures
1997
Polymeric materials find industrial applications that are comparable to those of metals and ceramics.1 In addition to the great variability via the synthesis of various monomers and the choice of the degree of polymerization (N), alloying of polymers finds increasing attention for combining favorable materials properties.1,2 But polymeric (binary) alloys (A,B) of flexible polymers with chain lengths NA, NB are also most interesting for testing theoretical concepts: changing NA, NB one controls the entropy of mixing, keeping intermolecular forces invariant. Variation of these control parameters thus allows stringent tests of the theories on miscibility, unmixing etc. Furthermore, the large s…
Role of C–H···Au and Aurophilic Supramolecular Interactions in Gold–Thione Complexes
2014
The role of noncovalent gold–hydrogen and aurophilic interactions in the formation of extended molecular systems of gold complexes was studied. Three new gold compounds with a heterocyclic thione ligand N-methylbenzothiazole-2-thione (mbtt), namely, [AuCl(mbtt)] (1), [AuBr(mbtt)] (2), and [Au(mbtt)2][AuI2]1–n[I3]n (3), were synthesized and characterized. The halide ligand had a considerable effect on the complex structures and thus to noncovalent contacts. Intermolecular C–H···Au and aurophilic Au···Au contacts were the dominant noncovalent interactions in structures 1–3 determining the supramolecular arrays of the gold complexes. In 1 and 2, unusual intermolecular C–H···Au gold–hydrogen co…
Intermolecular hydrogen bonding H···Cl in crystal structure of palladium(II)-bis(diaminocarbene) complex
2018
Abstract The reaction of bis(isocyanide)palladium complex cis-[PdCl2(CNXyl)2] (Xyl=2,6-Me2C6H3) with excess of 4,5-dichlorobenzene-1,2-amine in a C2H4Cl2/MeOH mixture affords monocationic bis(diaminocarbene) complex cis-[PdClC{(NHXyl)=NHC6H2Cl2 NH2}{C(NHXyl)=NHC6H2Cl2NH2}]Cl (3) in moderate yield (42%). Complex 3 exists in the solid phase in the H-bonded dimeric associate of two single charged organometallic cations and two chloride anions according to X-ray diffraction data. The Hirshfeld surface analysis for the X-ray structure of 3 reveals that the crystal packing is determined primarily by intermolecular contacts H–Cl, H–H, and H–C. The intermolecular hydrogen bonds N–H···Cl and C–H···C…
Structure Formation of Polymeric Building Blocks: Complex Polymer Architectures
2013
This chapter describes macromolecules with a complex structure, their defined aggregation in solution, their adsorption to surfaces, and their possible aggregation on surfaces. The term “complex structure” implies that the macromolecules show different, distinct structural elements or building blocks on a supra-atomic length scale. Key to understanding the complex structure of macromolecules, their aggregation, and adsorption to surfaces are intra- and intermolecular interactions such as van der Waals, electrostatic, π–π interactions, and hydrogen bonds.
The role of intermolecular forces in contact electrification on polymer surfaces and triboelectric nanogenerators
2019
This research was supported by the European Regional Development Fund within the project ‘‘Hybrid energy harvesting systems’’ 1.1.1.1./16/A/013.
Synthesis and solid state structures of macromolecular cylindrical brushes with varying side chain length
2004
Abstract Cylindrical brushes with a macromolecular backbone and well-defined side chains of different length (4≤ P n sc ≤38) were synthesized by polymerization of macromonomers. The effect of side chain length on the intermolecular order has been investigated by means of X-ray scattering on the melt-extruded samples. The increase of the side chain molar mass results in an increase of the intermolecular distance d according to d ∼( M n sc ) 0.476 . The contour length of the cylindrical brush polymers per main chain monomer unit, l m , was determined to slightly vary with side chain molar mass M n sc according to l m ∼( M n sc ) 0.059 . The resulting values are much less than the maximum exte…
Analysis of plasticization and reprocessing effects on the segmental cooperativity of polylactide by dielectric thermal spectroscopy
2021
Abstract In the present study, the dielectric properties of both neat and plasticized polylactide submitted to repeated extrusion and injection processes to simulate recycling were analysed. The dielectric relaxation spectrum, consisting of β and α relaxation, revealed the relevance of both acryl-PEG based plasticization and thermo-mechanical degradation induced by repeated extrusion and grinding-injection reprocessing cycles on polylactide (PLA). The β-relaxation has its origin in the intramolecular local motions of pendant groups of the PLA backbone, while the α-relaxation is representative of the intermolecular large-scale segmental motions of the PLA backbone. The addition of acryl-PEG …