Oligomers, nonlinear optics

Optical properties of cyanines can be usefiil for both chiral substituents/environments and also third-order nonlinear optical properties in polymer films. Methine-chain substituted die arbo cyanines have been prepared from a chiral dialdehyde (S)-(+)-2-j -butylmalonaldehyde [127473-57-8] (79), where the chiral properties are introduced via the chiral j -butyl group on the central methine carbon of the pentamethine (die arbo cyanine) chromophore. For a nonchiral oxadicarbocyanine, the dimeric aggregate form of the dye shows circular dichroism when trapped in y-cyclodextrin (80). Attempts to prepare polymers with carbocyanine repeat units (linked by flexible chains) gave oligomers with only two or three repeat units (81). However, these materials... 

One of the advances in the field of PET is the design of molecular devices, in which D and A pairs are ingeniously linked by covalent bridges (B) to form D-B-A dyads. Electron transfers between D and A across B in a controlled manner may thus display useful functionalities, such as molecular rectifiers [25], switches [26], biosensors [27], photovoltaic cells [28], and nonlinear optical materials [29]. Spacers that have been utilized are versatile, including small molecules, such as cyclohexane [30], adamantane [31], bicyclo[2.2.2]octane [32], steroids [33], and oligomers of... 

Recently, Pt-TEE molecular scaffolding yielded PTA oligomers with [Pt(PEt3)2] as spacer units [44]. Both the linear and nonlinear optical properties of these compounds revealed an... 

The extended rod structures and flexible phenol/formaldehyde oligomers offer interesting opportunities in the development of nonlinear optical (NLO) materials and Bakelite modifiers, respectively. 

Carbon-carbon bond coupling reactions that link alkynyl ligands are potentially important reactions for the preparation of alkyne oligomers (372) and nonlinear optical materials, as well as carbocyclic and heterocyclic compounds (373, 374). As a metal-mediated strategy to these... 

J.M. Andre and B. Champagne, in J.L. Bredas (Ed.), Nonlinear optical hyperpolarizabilities and electronic properties of oligomers and polymers the polyene story, from dyes to conducting and NLO systems, Conjugated oligomers, polymers, and dendrimers From polyacetylene to DNA, Bibliotheque Scientifique Francqui, De Boeck Universite, 1999, pp. 349-394. 

One of the main properties of interest in the field of conjugated polymers is the study of their dynamic nonlinear optical (NLO) response [112, 113]. It is a major challenge to obtain reliable dynamics of interacting electron systems. While for short oligomers there exist reasonable approximations for computing these properties [114], for longer chains even within model Hamiltonian approximations, the dynamic NLO coefficients had proved elusive. Yet most interest lies in the longer chains since the dynamic NLO properties exhibit dominant finite-size effects. 

B. Kirtman, Int. J. Quantum Chem., 43, 147 (1992). Nonlinear Optical Properties of Conjugated Polyenes from Ab Initio Finite Oligomer Calculations. 

B. Kirtman and B. Champagne, Int. Rev. Phys. Chem., 16, 389 (1997). Nonlinear Optical Properties of Quasilinear Conjugated Oligomers, Polymers and Organic Molecules. 

K-Conjugated polymers and oligomers are organic materials with many interesting and useful properties [1, 2], Examples of this class of materials include polyacetylene, polythiophene, polypyrrole, poly(phenylenevinylene) and their derivatives. Electronic conductivity, luminescence and nonlinear optical behavior are all observed in these materials and these properties have been exploited in applications such as electroluminescent devices (polymer light-emitting devices or PLEDs), electrostatic coatings, electrochromic windows, chemical sensors and memory devices [3-9]. 

Kirtman, B. 1992. Nonlinear optical properties of conjugated polymers from ab initio finite oligomer calculations. International Journal of Quantum Chemistry 43 (1) 147. 

Electroactive polymers and oligomers have been shown by several research goups to exhibit enhanced nonlinear optical (NLO) properties [64-67]. The intense oscillating electric field associated with a coherent laser beam causes a polarization reponse in the 7r-electron... 

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