Structural Transformations in Crystalline Oligomers of Polyparaphenylene

1988 ◽  
Vol 134 ◽  
Author(s):  
Kenneth N. Baker ◽  
Howard C. Knachel ◽  
Albert V. Fratini ◽  
W. Wade Adams
Keyword(s):  
Solid State ◽  
Low Temperature ◽  
Crystal Structures ◽  
Conformational Change ◽  
Room Temperature ◽  
State Transition ◽  
Structural Transformations ◽  
Thermal Contraction ◽  
Crystal Data ◽  
Solid State Transition

ABSTRACTWe report the room and low temperature crystal structures of the unsubstituted pquinquephenyl (PQP) and p-sexiphenyl (PSP), and substituted 22,45 -diphenyl-pquinquephenyl (DPQP), 22,65-diphenyl-p-septiphenyl (DPSP), and 1,2,4-triphenylbenzene (TPB) polyparaphenylene oligomers. The unsubstituted oligomers exhibit a solid state transition when cooled from room temperature to 110K, as indicated by a change in crystallographic space group. No transition is observed for the substituted oligomers other than the usual thermal contraction of the unit cell. The transition observed for the unsubstituted oligomers is interpreted in terms of a conformational change from an “averaged” planar structure to a static non-planar one. Comparisons of room temperature and low temperature crystal data are presented.

Solid-State Transition of Poly(butylene terephthalate) Induced by Mechanical Deformation

1980 ◽  
Vol 13 (1) ◽  
pp. 137-145 ◽  
Author(s):  
Kohji Tashiro ◽  
Yuzo Nakai ◽  
Masamichi Kobayashi ◽  
Hiroyuki Tadokoro
Keyword(s):  
Solid State ◽  
State Transition ◽  
Mechanical Deformation ◽  
Butylene Terephthalate ◽  
Solid State Transition

Effect of Solid State Transition on the Physical Stability of Suspensions Containing Bupivacaine Lipid Microparticles

2005 ◽  
Vol 10 (2) ◽  
pp. 309-318 ◽  
Author(s):  
Luk Chiu Li ◽  
Lihua Zhu ◽  
Jing-Feng Song ◽  
Jone-Shin Deng ◽  
Rubi Bandopadhyay ◽  
...  
Keyword(s):  
Solid State ◽  
State Transition ◽  
Physical Stability ◽  
Solid State Transition ◽  
Lipid Microparticles

Dimethyl-, Disilyl- and Digermylsulfide: Different Intermolecular Contacts in the Solid State

2004 ◽  
Vol 59 (6) ◽  
pp. 635-638 ◽  
Author(s):  
Norbert W. Mitzel ◽  
Udo Losehand
Keyword(s):  
Solid State ◽  
Low Temperature ◽  
Crystal Structures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Intermolecular Contacts

The compounds (H3C)2S, (H3Si)2S and (H3Ge)2S have been crystallised in situ on a diffractometer and their crystal structures determined by low-temperature X-ray diffraction. The molecules are present as monomers in the crystals. The aggregation of the molecules through secondary intermolecular contacts in the crystal is different: (H3C)2S is weakly associated into dimers by S···S contacts, whereas (H3Si)2S and (H3Ge)2S form Si···S and Ge···S contacts in an ice-analogous aggregation motif. Important geometry parameters are (H3C)2S: C-S 1.794(av) Å , C-S-C 99.2(1)°; (H3Si)2S: Si- S 2.143(1) Å , Si-S-Si 98.4°; (H3Ge)2S Ge-S 2.223(2) and 2.230(2) Å , Ge-S-Ge 98.2(1)◦.

Structure of TlSr2PrCu207−x by Rietveld analysis

1994 ◽  
Vol 9 (3) ◽  
pp. 194-199
Author(s):  
Hoong-Kun Fun ◽  
Ping Yang ◽  
Rusli Othman ◽  
Tsong-Jen Lee ◽  
Chiou-Chu Lai ◽  
...  
Keyword(s):  
Low Temperature ◽  
Crystalline Structure ◽  
Powder Diffraction ◽  
Room Temperature ◽  
Goodness Of Fit ◽  
Rietveld Analysis ◽  
Crystal Data ◽  
X Ray ◽  
Tetragonal System

The crystalline structure of new TlSr2PrCu207−x was obtained at room temperature (300 K) and low temperature (100 K) from X-ray powder diffraction with CuKα radiation using Rietveld analysis. TlSr2PrCu207−x has an isotypical structure with TlBa2CaCu207 (1212). At 300 K, crystal data: Tl0.864Sr2PrCu2O6.75, Mr=727.811, the tetragonal system, P4/mmm, a =3.85404(5) Å, c = 12.1046(2) Å, V=179.80 Å3, Z=1, Dx =6.7218 g cm−3, μ =1143.922 cm−1 (λ = 1.54051 Å), F(000)=317.0, the structure was refined with 28 parameters to Rwp=5.29%, Rp = 3.65% for 3551 step intensities and Rb=7.40%, Rf=639% for 155 peaks, “goodness of fit” 5=3.05. At 100 K, crystal data: Tl0.858Sr2PrCu2O6.61, Mr=724.345, the tetragonal system, P4/mmm, a =3.84872(6) Å, c = 12.0771(3) Å, V=178.89 Å3, Z=1, Dx=6.7235 g cm−3, μ=1146.939 cm−1 (λ= 1.54051 Å), F(000) = 315.4, the structure was refined with 26 parameters to Rwp=6.70%, Rp=5.11% for 2926 step intensities and Rb=7.83%, Rf=6.70% for 131 peaks, “goodness of fit” S = 1.75.

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