https://journals.sagepub.com/doi/pdf/10.1366/000370203321165133

Quantitative analysis using Raman spectrometry.

Polydiacetylenes (PDAs) are of great interest due to their π-conjugated backbone related properties, such as linear and nonlinear optical properties. As a consequence, design and preparation of PDAs assume enormous importance today. This review deals with one aspect of PDA, that is, design and preparation of the diacetylene monomers and their polymers, PDAs having conjugated side groups. The aim of such an investigation is to produce materials which exhibit large third-order nonlinear optical susceptibilities and which consequently, can be obtained in a form to be customised for optical devices.

Novel polydiacetylenes for optical materials: beyond the conventional polydiacetylenes

The bis(aryl)diacetylenes 1,4-bis(3-quinolyl)-1,3-butadiyne (1), 1,4-bis(4-isoquinolyl)-1,3-butadiyne (2), and 1,4-bis(3-pyridyl)-1,3-butadiyne (3) form strongly halogen bonded complexes with organ...

Crystal Engineering through Halogen Bonding. 2. Complexes of Diacetylene-Linked Heterocycles with Organic Iodides

The symmetric diacetylenes, 2,4-hexadiynylene dibenzoate 4 and 2,4-hexadiynylene bis(pentafluorobenzoate) 5, as well as the unsymmetric 6-(pentafluorobenzoyloxy)hexa-2,4-diynyl benzoate 6 were prepared and investigated with respect to their reactivity toward topochemical polymerization in the crystalline state. The 1:1 cocrystal 4.5 was successfully polymerized to the corresponding poly(diacetylene) copolymer 7, as evidenced by solid-state (13)C NMR and Raman spectroscopy, as well as single-crystal structure analysis of the monomer-polymer cocrystal. Thus, perfluorophenyl-phenyl interactions were utilized as complementary supramolecular synthons in the cocrystallization of two different diacetylene monomers and their unprecedented conversion into a strictly alternating diacetylene copolymer.

Alternating diacetylene copolymer utilizing perfluorophenyl-phenyl interactions.

We prepared partly crystalline polydiacetylenes (PDAs) by the solid-state polymerization of substituted benzyl 10,12-alkyldiynoates followed by the dissolution of the resulting polymers in refluxing 1,2-dichlorobenzene and subsequent reprecipitation. The obtained PDAs were soluble in organic solvents, such as chloroform and tetrahydrofuran, at room temperature. They showed thermochromism not only in the bulk and polymer matrices but also in solution. The UV–vis absorption spectrum of PDAs in solutions changed depending on the temperature along with a large hysteresis. The thermochromic properties were dependent on the structure of the PDAs, that is, the length of the alkyl side chains and also the structure of the substituent on the phenyl group. We have found that aggregates are formed in the solution when the temperature decreased on the basis of the NMR and dynamic light scattering measurement results.

Thermochromism of Polydiacetylenes in the Solid State and in Solution by the Self-Organization of Polymer Chains Containing No Polar Group

Changes in the FT-Raman spectrum of 1,4-bis(3-quinolyl)buta-1,3-diyne (DQ) as a function of γ-ray dosage is used to monitor the degree of monomer to polymer conversion in a solid-state to polymerization reaction. The relative intensities of the characteristic C≡C peaks in the nonresonant FT- Raman spectra provide a nondestructive quantitative means to measure the conversion from monomer to polymer

Kinetics of diacetylene polymerization : an FT-Raman study

Diacetylenes are known to undergo solid-state topochemical polymerisation to give polydiacetylenes. The reactivity of the monomer is controlled by the arrangement of the molecules in the crystal lattice wherein certain parametric conditions must be met for 1,4-addition to proceed. In the present paper, we investigated the structure–reactivity relationship of a class of diacetylene monomers. Heteroaryl moieties such as thiophene, benzo[b]thiophene and quinoline as one or both directly bound side groups of a diacetylene backbone were used. Thus various symmetrical as well as unsymmetrical diacetylenes were prepared and characterised. The solid-state polymerisation behaviour of these diacetylenes was studied in the light of their single-crystal X-ray structure. It was found that in order to react in the solid state, the diacetylenes must have the required lattice parameters. However, even when the required lattice parameters are met, the diacetylene monomers do not necessarily undergo solid-state 1,4-addition polymerisation, implying the existence of further controlling factors to determine reactivity.

Heteroaryl functionalised diacetylenes: preparation and solid-state reactivity

Solutions of poly[1,4-bis(3-quinolyl)buta-1,3-diyne] (PDQ) have shown the lowest energy electronic transitions of all the reported poly(diacetylene)s. Unusual solvato- and thermochromic behavior of PDQ in various polar and nonpolar environments is discussed. The role of hydrogen bonding appears crucial to the solution and chromic behavior in these solutions. π-Conjugation between the polymer backbone and the cross-conjugated heteroaromatic side groups appears to lead to chain segments with unusually extensive electron delocalization. Stable (over a period of 2 years), dark green, true solutions in phenol-acetonitrile (nonsolvent) (λ max = 733 nm) are obtained

Unusually Low Energy Electronic Transitions in Poly(diacetylene) Solutions: Solvato- and Thermochromic Behavior of Poly(1,4-bis(3-quinolyl)buta-1,3-diyne)

La polymerisation en phase solide par irradiation UV-visible ou gamma ou par recuit est partielle et donne des polymeres cristallins. La spectrometrie de reflexion suggere que les groupes aromatiques lateraux sont conjugues avec les electrons π de la chaine. La conductivite electrique du polymere dope par l'iode atteint 10 −6 S/cm

Synthesis and solid-state polymerization of a diaryldiacetylene - 1,4-bis(3-quinolyl)-1,3-butadiyne

Topochemical reactivity of some conjugated diacetylenes with πconjugating substituents upon exposure to γ-radiation, UV-visible radiation and upon thermal annealing is described. Few of the diacetylenes undergo solid state polymerization to provide corresponding polydiacetylenes. The reflectance spectra of the resultant polydiacetylenes showed significant backbone-sidegroup electron coupling. The third-order nonlinear susceptibility of two of the polydiacetylenes obtained were evaluated using Maker's fringe technique. The third-order nonlinear susceptibility, χ(3) value obtained for the two samples were in the order of 10−11 esu for the fully polymerized polydiacetylene films. These values are comparable to the values reported previously for PDAs with aromatic sidegroups.

Satya S. Talwar

Papers

Kinetics of diacetylene polymerization : an FT-Raman study

Heteroaryl functionalised diacetylenes: preparation and solid-state reactivity

Unusually Low Energy Electronic Transitions in Poly(diacetylene) Solutions: Solvato- and Thermochromic Behavior of Poly(1,4-bis(3-quinolyl)buta-1,3-diyne)

Synthesis and solid-state polymerization of a diaryldiacetylene - 1,4-bis(3-quinolyl)-1,3-butadiyne

Solid state polymerization of diacetylenes with π-conjugating substituents for third-order nonlinear optical properties