Stereospecific Polymerization in Urea Canal Complexes<sup>1</sup>

White, Donald R.

doi:10.1021/ja01506a031

Cited by 173 publications

(60 citation statements)

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“…The length of a molecule being included in the adduct should not play any role in that case. As examples of polymer adducts in which the included molecules exist as side additive groups of a polymer chain, the products of polymerization of urea and thiourea adducts with some monomers [7,8] can be mentioned. These polymer adducts readily dissociate when undergoing water action, resulting in free molecules of the polymer.…”

Section: Discussionmentioning

confidence: 99%

On the Structure of Beta-Cyclodextrin Polymer Adducts

Maciejewski¹,

Durski²

1981

Journal of Macromolecular Science: Part A - Chemistry

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Section: Discussionmentioning

confidence: 99%

On the Structure of Beta-Cyclodextrin Polymer Adducts

Maciejewski¹,

Durski²

1981

Journal of Macromolecular Science: Part A - Chemistry

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“…Several diyne and diene monomers undergo solidstate polymerization, leading to polymers with controlled chemical and stereostructures. [41][42][43][44][45][46][47] However, there has been no clear examples of solid-state polymerization of vinyl monomers, except for the reactions using solid matrices (inclusion polymerization) [48][49][50][51][52] and the DBF polymerization described here. 17 Although the details are still under investigation, cationic initiators can also effectively polymerize DBF.…”

Section: Dpe Dbf Styrenementioning

confidence: 99%

Synthesis, structure and function of π-stacked polymers

Nakano

2010

Polym J

127

101

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Macromolecular conformation often has a significant effect on the properties of polymeric materials, and hence, conformational control in synthesizing a polymer is an important goal in polymer science. As a new conformational motif of vinyl polymers having side-chain p-electronic groups, we have introduced a 'p-stacked structure' in which side-chain chromophores are regularly stacked on top of each other and main-chain C-C bonds have a nearly all-trans, zigzag conformation. p-Stacked polymers can be prepared by vinyl polymerization of dibenzofulvene (DBF) and its derivatives. On the basis of the controlled structure, poly(DBF) and its derivatives exhibit unique photophysical and electronic properties as vinyl polymers. In addition, introduction of chirality to p-stacked polymers was also achieved. In this review, the synthesis of poly(DBF) and its derivatives and their structural analyses and properties are described. Polymer Journal (2010) 42, 103-123; doi:10.1038/pj.2009 Keywords: charge transport; chirality; dibenzofulvene; helix; photophysical properties; p-stacked structureIn designing functional organic materials with desired properties, spatial arrangement control of constituent molecules is an important factor because molecules in a regulated assembly often indicate properties different from those in solution or in gas phase because of specific intermolecular interactions. Effective molecular assembly control can be achieved by arrangement of functional molecules as a part of a polymer chain with a regulated conformation and configuration in which the polymer backbone functions as a structural template or scaffold. This is possible either by polymerizing functional molecules as monomers or by attaching functional molecules through a chemical reaction to a polymer chain. In the former case, the functional molecules to be aligned need to have a polymerizable moiety such as a vinyl group; they are a part of monomers and become constituents of a polymer chain as a part of monomeric units, typically as side-chain groups. The monomer structure itself may significantly contribute to the formation of a regulated polymer chain structure through intermolecular repulsion or attraction. An advantage of these polymer-based methods over other methodologies developed mainly for low-molecular-weight compounds based on the accumulation of relatively weak forces is that molecular orders formed along a polymer chain are generally stable due to covalent bonds. Moreover, using a polymer chain, a very tight or close packing of molecules (monomeric units), which is not plausible for the method based on weak intermolecular attractions, is possible when the enthalpy gain in covalent bond formation by polymerization or by polymer reaction outweighs the loss in free energy in packing molecules tightly into a small space around the polymer chain.Although these polymer-based methods generally require more synthetic efforts than intermolecular-force-based methods, a wider variety of molecular orders may be possible on the basis of re...

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“…White [3] found a syndiotactic poly(vinyl chloride) (s-PVC) was obtained when VC monomer was polymerized in the urea canal complex (see Figure 1). It was the first attempt to control the steric configuration of tetrahedral (sp 3 ) backbone carbon atoms, utilizing inclusion polymerization. [1] Infrared absorption bands of the g-ray irradiated urea canal-type polymer were sharper than those of the normal polymer and the unique spectral patterns observed between 625-588 cm À1 demonstrated that the g-irradiated PVC achieved a highly stereoregular structure.…”

Section: Introductionmentioning

confidence: 99%

Why is Stereoregular Polyacrylonitrile Obtained by Polymerization in Urea Canals Isotactic?

Yang

El‐Shafei

Schilling³

et al. 2007

Macro Theory & Simulations

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Because stereoregular i‐PAN is obtained from the constrained polymerization of acrylonitrile monomer in expandable urea clathrates, we studied the inclusion compounds formed between guest AN and PANs and host cyclodextrins whose rigid channel diameters are in the range of the canals in urea clathrates. ICs of AN were successfully formed with α‐ and γ‐CDs but did not yield PANs, and only ICs between γ‐CD, and a‐ and i‐PANs were formed in solution. Modeling of AN and s‐ and i‐PAN‐CD‐ICs were performed using PM3 parameters to estimate their stabilities. We conclude that the polymerization of AN in urea clathrate channels produces predominantly i‐PAN as a consequence of its improved fit compared with s‐PAN.

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Stereospecific Polymerization in Urea Canal Complexes¹

Cited by 173 publications

References 1 publication

On the Structure of Beta-Cyclodextrin Polymer Adducts

On the Structure of Beta-Cyclodextrin Polymer Adducts

Synthesis, structure and function of π-stacked polymers

Why is Stereoregular Polyacrylonitrile Obtained by Polymerization in Urea Canals Isotactic?

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Stereospecific Polymerization in Urea Canal Complexes1

Cited by 173 publications

References 1 publication

On the Structure of Beta-Cyclodextrin Polymer Adducts

On the Structure of Beta-Cyclodextrin Polymer Adducts

Synthesis, structure and function of π-stacked polymers

Why is Stereoregular Polyacrylonitrile Obtained by Polymerization in Urea Canals Isotactic?

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Stereospecific Polymerization in Urea Canal Complexes¹