Tuning the Dynamic Fragility of Acrylic Polymers by Small Molecules: The Interplay of Molecular Structure

Soft Matter ◽  
2021 ◽  
Author(s):  
Yuanbiao Liu ◽  
Gaopeng Shi ◽  
Guozhang Wu

This report studied changes in dynamic fragility (m) of poly(butyl methacrylate) (PBMA) by introducing guest hindered phenols capable of forming double or triple intermolecular hydrogen bonds (inter-HBs) per molecule with...

1993 ◽  
Vol 71 (9) ◽  
pp. 1443-1449 ◽  
Author(s):  
Monique Perrin ◽  
Alain Thozet ◽  
Pilar Cabildo ◽  
Rosa Ma Claramunt ◽  
Eduard Valenti ◽  
...  

The title compound C12N6H14, 1, crystallizes in the space group P21/n (a = 8.222(2) Å, b = 27.336(8) Å, c = 5.574(2) Å, α = 90.00°, β = 100.97(4)°, γ = 90.00°), Z = 4, d = 1.308 g cm−3. The conformation about the N—C bonds linking the pyrazole rings can be defined as EZ, with "pyridine-like" nitrogen atoms in an anti disposition [Formula: see text] and "pyridine-like" and "pyrrole-like" nitrogen atoms in a syn disposition [Formula: see text] with regard to the central pyrazole. Intermolecular hydrogen bonds between the central and the terminal pyrazole ring of configuration Z form centrosymmetric dimers. They pack in sheets nearly parallel to the (−2 3 1) plane. Its tautomerization barrier has been determined in methanol-d4; the value, 11.9 kcal mol−1, is similar to those of 3,5-dimethyl-4-chloropyrazole (12.8 kcal mol−1) and 3,5-dimethyl-4-nitropyrazole (12.1 kcalmol−1). These values together with the shape of the conformational potential surface (calculated using the AM1 Hamiltonian) suggest that, in compound 1, prototropy and rotation about the N—C bonds linking the three pyrazole rings take place simultaneously.


1972 ◽  
Vol 50 (15) ◽  
pp. 2407-2412 ◽  
Author(s):  
M. N. G. James ◽  
G. J. B. Williams

A previously unknown alkaloid of molecular formula C15H20O2N2 was isolated from the dried root bark of EleagnusCommutata (Wolf willow or Silverberry). An X-ray analysis was undertaken to complete the structural characterization of the molecule. Columnar crystals obtained from diethyl ether have the unit cell constants, a = 13.1949(10) Å, b = 9.4525(6) Å, c = 12.1186(6) Å, β = 109°47(1)′ and belong to space group P21/c. The structure was solved using an automated symbolic addition procedure and refined by block-diagonal least-squares to weighted and unweighted R factors of 6.25% and 4.30%, respectively. The previous structural studies were shown to be essentially correct except for the incorrect placement of the phenolic hydroxyl on C(5) of the oxindole nucleus. The correct molecular structure is implied by the systematic name given. The —OH group engages in two intermolecular hydrogen bonds with the two nitrogen atoms, but the carbonyl moiety is not involved in any such interactions.


2013 ◽  
Vol 683 ◽  
pp. 357-360
Author(s):  
Hai Xing Liu ◽  
Jing Zhong Xiao ◽  
Ping Yang ◽  
Zhang Xue Yu ◽  
Qing Hua Zhang ◽  
...  

A novel ytterbium chloride phenanthroline [YbCl4]·[C12H8N2]·(H2O) has been synthesized from a single solution reaction and the crystal structure has been determined by means of single-crystal X-ray diffraction. The Yb atom is coordinated by six Cl atoms. The plane quadrilateral is formed by two Cl2 and two Yb atoms. Molecules form O—H…Cl , O—H…O , O—H…N intramolecular and intermolecular hydrogen bonds and stabilized the molecular structure.


2012 ◽  
Vol 9 (2) ◽  
pp. 87
Author(s):  
Mohd Abdul Fatah Abdul Manan ◽  
M. Ibrahim M. Tahir ◽  
Karen A. Crouse ◽  
Fiona N.-F. How ◽  
David J. Watkin

The crystal structure of the title compound has been determined. The compound crystallized in the triclinic space group P -1, Z = 2, V = 1839 .42( 18) A3 and unit cell parameters a= 11. 0460( 6) A, b = 13 .3180(7) A, c=13. 7321 (8) A, a = 80.659(3 )0, b = 69 .800(3 )0 and g = 77 .007 (2)0 with one disordered dimethylsulfoxide solvent molecule with the sulfur and oxygen atoms are distributed over two sites; S101/S102 [site occupancy factors: 0.6035/0.3965] and 0130/0131 [site occupancy factor 0.3965/0.6035]. The C22-S2 l and C 19-S20 bond distances of 1. 779(7) A and 1. 788(8) A indicate that both of the molecules are connected by the disulfide bond [S20-S21 2.055(2) A] in its thiol form. The crystal structure reveals that both of the 5-bromoisatin moieties are trans with respect to the [S21-S20 and CI 9-Nl 8] and [S20-S21 and C22-N23] bonds whereas the benzyl group from the dithiocarbazate are in the cis configuration with respect to [S21-S20 and C19-S44] and [S20-S21 and C22-S36] bonds. The crystal structure is further stabilized by intermolecular hydrogen bonds of N9-H35···O16 formed between the two molecules and N28-H281 ···O130, N28-H281 ···O131 and C4 l-H4 l l ···O 131 with the solvent molecule.


2021 ◽  
Vol 44 (1) ◽  
pp. 213-217
Author(s):  
Waly Diallo ◽  
Hélène Cattey ◽  
Laurent Plasseraud

Abstract Crystallization of [(Ph3Sn)2SeO4] ⋅ 1.5H2O in methanol leads to the formation of [{(Ph3Sn)2SeO4} ⋅ CH3OH] n (1) which constitutes a new specimen of organotin(IV) selenate derivatives. In the solid state, complex 1 is arranged in polymeric zig-zag chains, composed of alternating Ph3Sn and SeO4 groups. In addition, pendant Ph3Sn ⋅ CH3OH moieties are branched along chains according to a syndiotactic organization and via Sn-O-Se connections. From a supramolecular point of view, intermolecular hydrogen bonds established between the selenate groups (uncoordinated oxygen) and the hydroxyl functions (CH3OH) of the pendant groups link the chains together.


APL Materials ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 031102
Author(s):  
Hui Ye ◽  
Wang-Hua Hu ◽  
Wei-Jian Xu ◽  
Ying Zeng ◽  
Xiao-Xian Chen ◽  
...  

1986 ◽  
Vol 64 (1) ◽  
pp. 142-147 ◽  
Author(s):  
Suzanne Deguire ◽  
François Brisse ◽  
Jacques Ouellet ◽  
Rodrigue Savoie

A stoichiometric complex of formula (COOH)2•2H2O•18-crown-6 has been obtained from oxalic acid and the macrocyclic polyether 18-crown-6. The crystals of the complex have a monoclinic unit cell and belong to the P21/c space group. The components in the adduct are linked through hydrogen bonds in a polymer-like fashion: -crown–H2O–HOOCCOOH–OH2–crown–, where the oxalic acid molecules are present in two distinct disordered orientations. The infrared and Raman spectra of the complex are also reported and interpreted.


2015 ◽  
Vol 71 (4) ◽  
pp. 262-265 ◽  
Author(s):  
Subramanya Pingali ◽  
James P. Donahue ◽  
Florastina Payton-Stewart

Tetrahydroberberine (systematic name: 9,10-dimethoxy-5,8,13,13a-tetrahydro-6H-benzo[g][1,3]benzodioxolo[5,6-a]quinolizine), C20H21NO4, a widely distributed naturally occurring alkaloid, has been crystallized as a racemic mixture about an inversion center. A bent conformation of the molecule is observed, with an angle of 24.72 (5)° between the arene rings at the two ends of the reduced quinolizinium core. The intermolecular hydrogen bonds that play an apparent role in crystal packing are 1,3-benzodioxole –CH2...OCH3and –OCH3...OCH3interactions between neighboring molecules.


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