Preferential intermolecular recognition is observed when copolymer 3 formed from a solution containing 1, 2, and 4 (see scheme). This halogen-bonded also obtained crystallization of mixture 1 2. Thus halogen bonding can be more effective than hydrogen bonding, which responsible for the formation 5 4, in driving self-assembly organic derivatives.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructure of .beta.-Isotactic Polypropylene: A Long-Standing Structural PuzzleStefano V. Meille, Dino R. Ferro, S. Brueckner, Andrew J. Lovinger, and Frank PaddenCite this: Macromolecules 1994, 27, 9, 2615–2622Publication Date (Print):April 1, 1994Publication History Published online1 May 2002Published inissue 1 April 1994https://pubs.acs.org/doi/10.1021/ma00087a034https://doi.org/10.1021/ma00087a034research-articleACS PublicationsRequest reuse...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTγ-Isotactic polypropylene. A structure with nonparallel chain axesStefano V. Meille, S. Bruckner, and W. PorzioCite this: Macromolecules 1990, 23, 18, 4114–4121Publication Date (Print):September 1, 1990Publication History Published online1 May 2002Published inissue 1 September 1990https://pubs.acs.org/doi/10.1021/ma00220a014https://doi.org/10.1021/ma00220a014research-articleACS PublicationsRequest reuse permissionsArticle...

Halogen bonds, attractive intermolecular interactions between perfluoroalkyl bromides and bromide ions, are present in cocrystals of (−)-sparteinium hydrobromide (1) (S)-1,2-dibromohexafluoropropane (2; shown schematically), result enantiopure infinite supramolecular helices. The perfluorocarbon–hydrocarbon self-assembly allows the resolution racemic 2.

We describe the results of quantum chemical calculations (DFT and MP2) on intermolecular interactions involving ammonia halofluoromethanes. The equilibrium C−X···N geometries are linear X···N distances shorter than sum van der Waals radii. binding energies CF3X···NH3 increase from 2 to 6 kcal/mol following sequence X = Cl, Br, I. Also, progressive introduction F atoms in methyliodides raises interaction energy for CH3I CF3I. Therefore, halogen bonding perfluorinated alkylhalides appropriate...

Halogenbrücken können effektiver sein als Wasserstoffbrücken, wenn es um die Selbstassoziation organischer Verbindungen geht: Aus einer Lösung, 1, 2 und 4 enthält, entsteht das Halogen-verbrückte Copolymer 3 (das auch bei der Kristallisation Mischung aus 1 erhalten wird) nicht etwa 5 sich durchaus in Abwesenheit von bildet).

High molecular mass and high regioregularity favor the more common polymorph (form I) of poly(3-alkylthiophenes) substantially extend toward temperatures existence domain 2D mesomorphic phase, which these systems access above 70−80 °C. Morphological observations indicate that in thin films form I planar polythiophene main chains lie roughly edge-on parallel to film surface, while side are approximately orthogonal substrate. Evidence relative second II), easily obtained with...

We present the results of a thorough molecular modeling study several alkylthiophene-based oligomers and polymers. In particular, we consider two polymers whose limit-ordered crystal structures have been recently reported by our group, on basis powder X-ray data analysis: poly(3-(S)-2-methylbutylthiophene) (P3MBT) form I' poly(3-butylthiophene) (P3BT). first describe development series general purpose force fields for simulation these related systems. The incorporate ab initio calculations...

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTPerfluorocarbon−Hydrocarbon Self-Assembling. 1D Infinite Chain Formation Driven by Nitrogen···Iodine InteractionsVincenzo Amico, Stefano Valdo Meille, Eleonora Corradi, Maria Teresa Messina, and Giuseppe ResnatiView Author Information C.N.R. - Centro Studio Sostanze Organiche Naturali Dipartimento di Chimica, Politecnico via Mancinelli 7, I-20131 Milano Scienze Chimiche, Università viale A. Doria 6, 95125 Catania, Italy Cite this: J. Am....

The role of polymer side chains in conferring selectivity to a sensing organic thin-film transistor is investigated. Alkyl- and alkoxy-substituted regioregular polythiophenes are used as active layers, set volatile compounds carrying different chemical functionalities employed analytes. responses both polymer-based quartz crystal microbalance sensors evaluated compared; the mechanisms involving weak interactions between analyte polymers' discussed well.

We present the characterization of LiX-doped room-temperature ionic liquids (ILs) based on N-butyl-N-methyl pyrrolidinium (PYR14) cation with two fluorinated anions: (trifluoromethanesulfonyl)-(nonafluorobutanesulfonyl)imide (X═IM14) and bis(pentafluoroethanesulfonyl)imide (X═BETI). The new data are also compared previous results PYR14TFSI (bis(trifluoromethanesulfonyl)imide). Their local organization has been investigated via NMR nuclear Overhauser effect (NOE) experiments for {(1)H-(19)F}...

Abstract The non‐parallel chain structure determined for γ‐phase isotactic polypropylene (γ‐iPP) is confirmed by Rietveld analysis highly high molecular mass iPP crystallized at 200 MPa. new refinement shows that: (i) stereoregularity or crystallization pressure do not significantly influence the lattice dimensions; (ii) defect inclusion in γ‐iPP crystals unlikely. α and γ forms have nearly identical bulk internal energy density, but α‐iPP should be normally kinetically favored over which...

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTStereoselective Additions of α-Lithiated Alkyl-p-tolylsulfoxides to N-PMP(fluoroalkyl)aldimines. An Efficient Approach Enantiomerically Pure Fluoro Amino CompoundsPierfrancesco Bravo, Alessandra Farina, Valery P. Kukhar, Andrey L. Markovsky, Stefano V. Meille, Vadim A. Soloshonok, Alexander E. Sorochinsky, Fiorenza Viani, Matteo Zanda, and Carmela ZappalàView Author Information C.N.R.−Centro di Studio per le Sostanze Organiche Naturali,...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe structure of poly(D-(-)-.beta.-hydroxybutyrate). A refinement based on the Rietveld methodSergio Bruckner, S. V. Meille, L. Malpezzi, A. Cesaro, Navarini, and R. TomboliniCite this: Macromolecules 1988, 21, 4, 967–972Publication Date (Print):April 1, 1988Publication History Published online1 May 2002Published inissue 1 April 1988https://pubs.acs.org/doi/10.1021/ma00182a021https://doi.org/10.1021/ma00182a021research-articleACS...

The first solvent-free crystal structure of PCBM, an organic semiconductor widely used in nanocrystalline films plastic solar cells, is reported and its relevance to structure–property relationships discussed. PCBM structure, obtained from o-dichlorobenzene solvates by solvent abstraction, was solved using powder diffraction, demonstrating this possibility for functionalized fullerenes.

We present a computational analysis of electron transport within several crystalline fullerene derivatives. Different polymorphs are characterized by one-, two- or three-dimensional charge networks.

Alkoxy‐substituted thiophenes have been shown to yield polymers with a reduced bandgap. An X‐ray investigation of two symmetrical pentoxy‐substituted 2,2′‐bithienyls is reported, and their structure packing described. It suggested that the extra rigidity stability alkoxythiophene oligomers accounts for lower solubility higher melting points compared alkyl‐substituted analogues.

Abstract Partially modified retro‐ (PMR) and retro‐inverso (PMRI) ψ[NHCH(CF 3 )]Gly peptides, a conceptually new class of peptidomimetics, have been synthesized in wide structural diversity variable length by aza‐Michael reaction enantiomerically pure α‐amino esters peptides with geometrically N ‐4,4,4‐trifluorocrotonoyl‐oxazolidin‐2‐ones. The factors underlying the observed moderate to good diastereocontrol investigated. conformations model PMR‐ψ[NHCH(CF tripeptides studied solution 1 H NMR...