Rapid Solid-Phase Syntheses of Conjugated Homooligomers and [AB] Alternating Block Cooligomers of Precise Length and Constitution

Abstract

A new iterative divergent/convergent solid-phase synthesis of precisely defined oligomers is described. The starting monomer is affixed to the solid support so that both ends are free for growth. The polymer-supported n-mer bearing alpha,omega-terminal iodides is divided into two portions. The smaller portion is converted to the polymer-supported (n + 2)-mer by coupling an alpha,omega-dialkyne to the two iodide ends. The larger portion is liberated from the polymer support and then coupled with the polymer-supported portion to form a polymer-supported (3n + 2)-mer with new alpha,omega-terminal iodide end groups. The process is then repeated. The solid-supported material thereby grows in two directions, unlike the common approach of unidirectional growth. This polymer-supported strategy serves as a pseudo high dilution system so that unwanted polymerization does not ensue. Therefore, after each iteration, the oligomer length is more than tripled, making this a rapid growth methodology for precise oligomer syntheses. The methodology is demonstrated by the synthesis of a 17-mer oligo(1,4-phenylene ethynylene) of approximately 120 Å length in seven steps with an overall 20% yield. This solid-supported divergent/convergent tripling protocol is also used for the synthesis of an [AB] alternating block 23-mer containing oligo(1,4-phenylene ethynylene)s and oligo(2,5-thiophene ethynylene)s in an overall 21% yield. The length of the 23-mer is approximately 160 Å.

Synthesis and self-assembly of novel porphyrin molecular wires

“…The length of polymer wire can be controlled by the solid-phase reaction [19,20]. For example, it can be achieved by oxidized-coupling of a porphyrin, in which one side of its acetylene is fixed by a solid phase, to diethynylporphyrin, in which one side is free from TMS protection.…”

Giant meso–meso‐Linked Porphyrin Arrays of Micrometer Molecular Length and Their Fabrication

“…[12] This method, when combined with solid-phase synthesis, furnished a block-alternating 23-mer consisting of oligo(1,4-phenylene ethynylene)s and oligo(2,5-thiophene ethynylene)s, the molecular length of which reached about 160 . [13] Conversely, oligo-and polythiophenes have been actively exploited for molecular devices, such as organic conductive materials, electroluminescence (EL) devices, organic lightemitting diodes (OLEDs), field-effect transistors (FETs), and so forth. [14][15][16][17] Roncali et al reported the synthesis and characterization of monodisperse soluble oligothienylenevinylenes with chain lengths up to 10 nm.…”

Organic Chemistry of Polyanilines: Tailoring Properties to Technological Applications~!2008-08-19~!2008-09-11~!2008-11-28~!

“…Combinatorial synthesis could be carried out in solution, but the simplicity of workout with immobilized substrates makes it the method of choice. Indeed, the solid phase synthesis has been used to synthesise conjugated molecules of precise length [70][71][72]. The low solubility of conducting polymers in most solvents makes them ideal to perform combinatorial chemistry reactions on the polymer.…”