From dendrimers to fractal polymers and beyond

O advento da química dendrítica tem facilitado a pesquisa de materiais por permitir o controle preciso do posicionamento do componente funcional na arquitetura macromolecular. Os protocolos sintéticos iterativos usados para construção dos dendrímeros foram desenvolvidos baseados no desejo de elaborar moléculas extremamente ramificadas, com alta massa molecular, massa exata e funcionalidade planejada. Arborols, inspirados em árvores e precursores de macromoléculas utilitárias, conhecidas hoje como dendrímeros, foram os primeiros exemplos a empregar blocos de construção de ramificação-C 1→3; Características físicas dos Arborols, incluindo a sua forma globular, excelente solubilidade, e agregação, combinam-se para revelar o potencial supramolecular inerente (isto é, a micela unimolecular) destas espécies únicas. A arquitetura que é característica dos materiais dendríticos também exibe qualidades fractais com base em estruturas repetitivas, ramificadas e auto-similares. Assim, o design fractal e os aspectos supramoleculares destas construções são sugestivas de um campo maior de materiais fractais que incorporam geometrias repetidas. O uso de terpiridina-M2+-terpiridina (onde, M = Ru, Zn, Fe, etc) em conjunto com algoritmos matemáticos tais como as formas da base do Triângulo de Seirpinski, tem permitido o início da exploração da construção de materiais fractais. A propensão da auto-criação de moléculas fractais para arquiteturas de ordem superior adiciona outra dimensão para essa nova arena de materiais e construção de compostos.The advent of dendritic chemistry has facilitated materials research by allowing precise control of functional component placement in macromolecular architecture. The iterative synthetic protocols used for dendrimer construction were developed based on the desire to craft highly branched, high molecular weight, molecules with exact mass and tailored functionality. Arborols, inspired by trees and precursors of the utilitarian macromolecules known as dendrimers today, were the first examples to employ predesigned, 1 → 3 C-branched, building blocks; physical characteristics of the arborols, including their globular shapes, excellent solubilities, and demonstrated aggregation, combined to reveal the inherent supramolecular potential (e.g., the unimolecular micelle) of these unique species. The architecture that is a characteristic of dendritic materials also exhibits fractal qualities based on self-similar, repetitive, branched frameworks. Thus, the fractal design and supramolecular aspects of these constructs are suggestive of a larger field of fractal materials that incorporates repeating geometries and are derived by complementary building block recognition and assembly. Use of terpyridine-M2+-terpyridine (where, M = Ru, Zn, Fe, etc) connectivity in concert with mathematical algorithms, such as forms the basis for the Seirpinski gasket, has allowed the beginning exploration of fractal materials construction. The propensity of the fractal molecules to self-assemble into higher order architectures adds another dimension to this new arena of materials and composite construction

Synthesis of Potential Agrochemicals and Reactions of Vinamidinium and Azavinamidinium Salts with Organometallic/Borane Reagents and Activated Nitrales

This report discusses research which was conducted in two areas: the synthesis of potential agrochemicals and the study of vinamidinium and azavinamidinium salt chemistry. Four classes of compounds were synthesized and characterized in the study of new potential agrochemicals. These compounds include diacylhydrazines, semicarbazides, 2,5-disubstituted-1,3,4-oxadiazoles and bis-2,5-disubstituted-1,3,4-oxadiazoles. The reaction of [3-(dimethylamino)-2-azaprop-2-en-1-ylidene] dimethylammonium chloride (Gold\u27s reagent) with organometallic/borane reagents was examined in efforts to find convenient syntheses for N,N-dimethylamino substituted alkyl and aryl compounds. Additionally, the reaction of 1,5-diazapentadienium chloride (Nair\u27s reagent) with nitrile activated alkanes was examined to find a convenient synthesis of 3-substituted pyridines. Subsequent intramolecular ring closure of the dienaminonitriles was unsuccessful. Finally, this report reveals the experimental procedures and conditions used for the synthesis of these products and offers explanations of the data as well as recommendations for future research

Detection and functionalization of dendrimers

A method of detecting unreacted termini within a dendritic structure is achieved by exposing a dendrimer to a single generating compound capable of bonding to and tagging a deprotected but uncoupled termini. A signal generated by the signal generating compound to an otherwise uncoupled termini provides detection of the unreacted termini

Lock and key micelles

A lock unimolecular micelle includes at least one engineered acceptor specifically binding a ligand (or specifically a âkeyâ unimolecular micelle) thereto. A key unimolecular micelle comprises a core molecule and a plurality of branches extending therefrom, at least one of the branches including a shank portion extending therefrom having a terminal moiety at an end thereof for binding to a complimentary acceptor of a lock unimolecular micelle. Together, the lock and key micelles form a unit, either irreversibly or reversibly bound wherein the lock micelles is a soluble receptor engineered to specifically bind to the specifically engineered key micelle

Lock and key micelles

A lock unimolecular micelle includes at least one engineered acceptor specifically binding a ligand (or specifically a key unimolecular micelle) thereto. A key unimolecular micelle comprises a core molecule and a plurality of branches extending therefrom, at least one of the branches including a shank portion extending therefrom having a terminal moiety at an end thereof for binding to a complimentary acceptor of a lock unimolecular micelle. Together, the lock and key micelles form a unit, either irreversibly or reversibly bound wherein the lock micelles is a soluble receptor engineered to specifically bind to the specifically engineered key micelle

T-butyl cascade polymers

A method for forming cascade polymers specifically utilizing the amine monomer of the formula The monomer is made by initially reacting nitromethane and CH2═CHCO2—TBu by nucleophilic addition to form the triester nitrotrialkanoate of the formula and then reducing the nitrosubstituent to afford the said amine monomer