Structural study on syndiotactic polystyrene: 4. Formation and crystal structure of molecular compound with iodine

Chatani, Yôzô; Inagaki, Toru; Shimane, Yukio; Shikuma, Haruo

doi:10.1016/0032-3861(93)90007-w

Cited by 173 publications

(185 citation statements)

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“…It has been reported in the literature that syn-PS was observed in four crystalline forms, namely a, b, g, and d. [23] However, the polymorphic behavior of syn-PS became complicated by the fact that it is possible to produce clathrated forms when the a, g, and d crystalline forms are treated with either THF, halogenated, or aromatic solvents. [24] According to these reported results, we chose three representative diblock copolymer samples with different styrene contents (Table 2, runs 2, 7, and 9) for X-ray powder diffraction analysis (WXRD). As shown in Figure 6a, the X-ray powder profile of (cis-1,4-PBD)-block-(syn-PS) diblock copolymer, which has a low styrene molar fraction (Table 2, run 2, x S = 12.7 mol %), displays broad and very low intensity signals at 2q = 7.8, 10.0, 17.4, 19.9, 23.1, and 28.18, indicating a low crystallinity.…”

Section: Runmentioning

confidence: 99%

A Lutetium Allyl Complex That Bears a Pyridyl‐Functionalized Cyclopentadienyl Ligand: Dual Catalysis on Highly Syndiospecific and cis‐1,4‐Selective (Co)Polymerizations of Styrene and Butadiene

Jian

Tang

Cui

2010

Chemistry A European J

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A novel linked-half-sandwich lutetium-bis(allyl) complex [(C(5)Me(4)-C(5)H(4)N)Lu(η(3)-C(3)H(5))(2)] (1) attached by a pyridyl-functionalized cyclopentadienyl ligand was synthesized and fully characterized. Complex 1 in combination with [Ph(3)C][B(C(6)F(5))(4)] exhibited unprecedented dual catalysis with outstanding activities in highly syndiotactic (rrrr>99%) styrene polymerization and distinguished cis-1,4-selective (99%) butadiene polymerization, respectively. Strikingly, this catalyst system exhibited remarkable activity (396 kg copolymer (mol(Lu) h)(-1)) for the copolymerization of butadiene and styrene. Irrespective of whether the monomers were fed in concurrent mode or sequential addition of butadiene followed by styrene, diblock copolymers were obtained exclusively, which was confirmed by a kinetics investigation of monomer conversion of copolymerization with time. In the copolymers, the styrene incorporation rate varied from 4.7 to 85.4 mol%, whereas the polybutadiene (PBD) block was highly cis-1,4-regulated (95%) and the polystyrene segment remained purely syndiotactic (rrrr>99%). Correspondingly, the copolymers exhibited glass transition temperatures (T(g)) around -107 °C and melting points (T(m)) around 268 °C; typical values for diblock microstructures. Such copolymers cannot be accessed by any other methods known to date. X-ray powder diffraction analysis of these diblock copolymers showed that the crystallizable syndiotactic polystyrene (syn-PS) block was in the toluene δ clathrate form. The AFM micrographs of diblock copolymer showed a remarkable phase-separation morphology of the cis-1,4-PBD block and syn-PS block. This represents the first example of a lutetium-based catalyst showing both high activity and selectivity for the (co)polymerization of styrene and butadiene.

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Section: Runmentioning

confidence: 99%

A Lutetium Allyl Complex That Bears a Pyridyl‐Functionalized Cyclopentadienyl Ligand: Dual Catalysis on Highly Syndiospecific and cis‐1,4‐Selective (Co)Polymerizations of Styrene and Butadiene

Jian

Tang

Cui

2010

Chemistry A European J

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“…[11][12][13][14] Polymer films, which are able to detect, amplify, and memorize the chirality of several volatile organic molecules have been recently reported. [11][12][13][14] These chiral sensing films are based on syndiotactic polystyrene (s-PS), a stereoregular polymer, [15][16][17][18][19][20][21][22] with a very complex polymorphic behavior, [19][20][21][22] which involves two crystalline phases (a 23,24 and b 25,26 ) with transplanar chains and three crystalline phases (g, [27][28][29] d, [30][31][32] and e [33][34][35] ), as well as many different cocrystalline phases with low-molecular-mass guest molecules, [36][37][38][39][40][41][42][43] with s(2/1)2 helices. Recently, the origin of this chiral sensitivity has been elucidated by Infrared Reflection Absorption Spectroscopy (IRRAS), Vibrational Circular Dichroism (VCD), and X-ray diffraction measurements.…”

Section: Introductionmentioning

confidence: 99%

Induced vibrational circular dichroism and polymorphism of syndiotactic polystyrene

2010

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The intense circular dichroism (CD) phenomena, as induced in amorphous samples of syndiotactic polystyrene (s-PS) by cocrystallization with nonracemic volatile guest molecules (carvone and limonene), have been investigated by Vibrational Circular Dichroism (VCD) measurements and X-ray diffraction characterizations. Moreover, the stability of these CD phenomena after thermal and solvent treatments, leading to different polymorphic crystalline phases of s-PS, has been studied. The CD phenomena remain stable not only after guest extraction but also after thermal annealing procedures leading to the helical γ phase or to the transplanar α phase. The CD phenomena are instead reduced for the solvent treatments involving at least partial dissolution and crystallization that lead to the helical ε phases and even lost for thermal treatments involving melting and crystallization that lead to the β phase. The reported results indicate that the intense CD phenomena observed for s-PS films are due to a supramolecular chirality associated with the native cocrystal morphology.

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“…[1,2] The crystal structure of clathrate phase embedding toluene, [3] iodine, [4] or 1,2-dichloroethane [5] are in fact very similar.…”

Section: Introductionmentioning

confidence: 99%

²H NMR Study of Aromatic Guest Dynamics in Clathrate Phases of Syndiotactic Polystyrene

Albunia

Graf

Guerra

et al. 2005

Macro Chemistry & Physics

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Summary: 2H NMR solid‐state spectra of aromatic molecules (benzene, toluene, chlorobenzene, naphthalene) included in clathrate phases of syndiotactic polystyrene (s‐PS) or absorbed in the amorphous phase of s‐PS, have been recorded and analyzed for a broad range of temperature (230–360 K). The dynamic processes accessible to aromatic molecules absorbed in s‐PS clathrate phases are essentially temperature independent for the whole temperature range under investigation. Moreover, the molecular re‐orientations reflected in the NMR line‐shapes are similar to those accessible to the same molecules when absorbed in polystyrene amorphous phase at temperatures substantially lower than the polymer glass transition temperature. A simulation procedure for 2H NMR line‐shape analysis has been used to establish models for the dynamic processes of the different aromatic guest molecules.Solid‐state 2H NMR spectrum of naphtalene‐d8 in the amorphous phase of a semi‐crystalline s‐PS film (A), in the s‐PS clathrate phase (B) and the simulated spectrum for a static CD bond (C).magnified imageSolid‐state 2H NMR spectrum of naphtalene‐d8 in the amorphous phase of a semi‐crystalline s‐PS film (A), in the s‐PS clathrate phase (B) and the simulated spectrum for a static CD bond (C).

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Structural study on syndiotactic polystyrene: 4. Formation and crystal structure of molecular compound with iodine

Cited by 173 publications

References 9 publications

A Lutetium Allyl Complex That Bears a Pyridyl‐Functionalized Cyclopentadienyl Ligand: Dual Catalysis on Highly Syndiospecific and cis‐1,4‐Selective (Co)Polymerizations of Styrene and Butadiene

A Lutetium Allyl Complex That Bears a Pyridyl‐Functionalized Cyclopentadienyl Ligand: Dual Catalysis on Highly Syndiospecific and cis‐1,4‐Selective (Co)Polymerizations of Styrene and Butadiene

Induced vibrational circular dichroism and polymorphism of syndiotactic polystyrene

²H NMR Study of Aromatic Guest Dynamics in Clathrate Phases of Syndiotactic Polystyrene

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Structural study on syndiotactic polystyrene: 4. Formation and crystal structure of molecular compound with iodine

Cited by 173 publications

References 9 publications

A Lutetium Allyl Complex That Bears a Pyridyl‐Functionalized Cyclopentadienyl Ligand: Dual Catalysis on Highly Syndiospecific and cis‐1,4‐Selective (Co)Polymerizations of Styrene and Butadiene

A Lutetium Allyl Complex That Bears a Pyridyl‐Functionalized Cyclopentadienyl Ligand: Dual Catalysis on Highly Syndiospecific and cis‐1,4‐Selective (Co)Polymerizations of Styrene and Butadiene

Induced vibrational circular dichroism and polymorphism of syndiotactic polystyrene

2H NMR Study of Aromatic Guest Dynamics in Clathrate Phases of Syndiotactic Polystyrene

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²H NMR Study of Aromatic Guest Dynamics in Clathrate Phases of Syndiotactic Polystyrene