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The synthesis and photophysical study of a series of solution-processible phosphorescent iridium complexes are described. These covalently bound materials show improvements in efficiency over simple blends and will form the basis of future investigations into energy-transfer processes occurring in light-emitting diodes.

The key steps involved in the enantioselective synthesis of (+)-laurencin (1), achieved in 27 stages from (R)-malic acid (20), involved methylenation of lactone (49), intramolecular hydrosilation of enol ether (14) and a carbon homologation of diol (13). This gave a key ethyl substituted cyclic ether (59). 49 was obtained through Claisen ring expansion, alpha-hydroxylation and Yamaguchi lactonization. The synthesis of 1 was completed with an elaboration of the (E)-pentenynyl side chain and introduction of bromine.

Poly(p-phenylenevinylene) (PPV) based conjugated polymers have characteristic portions of high and low HOMO-LUMO gap energy which is chemically and electronically regulated using molecular engineering techniques. Two conjugated poly(arylenevinylene) related to PPV and MEH-PPV are used as light-emitting compounds in electroluminescent devices. Methoxy withdrawing groups in precursor polymers heated to a temperature of 220 degrees celsius effect the synthesis of these conjugated polymers. Partially conjugated polymers characterized by regions of high and low HOMO-LUMO gap energy is obtained during thermal treatment of precursor polymers. These partially conjugated polymers are 30 times more efficient than PPV in exhibiting electroluminescence.

An acid-sensitive semiperfluoroalkyl resorcinarene, soluble in hydrofluoroethers (HFEs), is developed and used is organic electronics. The orthogonality to common organic electronic materials has enabled multilevel patterning as shown by the fabrication of overlaid patterns.

An alkylative cyclization route to defect-free, 9,9-dioctyl-9H-fluorene is described. The polyfluorenes exhibited minimal green emission attributable to fluorene formation when prepared by Yamamoto and Suzuki polymerization of detect-free monomers.

The rational design, synthesis and characterization of a serives of novel perfluorinated dendrons are described. Perfluorinated tails are attached to the periphery in order to provide solubility in supercritical carbon dioxide and also to enhance the hydrophobicity and the stability of self-assembled monolayers.

An investigation was carried out about the nature of Dexter triplet energy transfer between bonded systems of a red phosphorescent iridium complex and a conjugated polymer, polyfluorene by using electrophosphorescent organic light-emitting diodes. The results indicate that the incorporation of a -[(C[H.sub.2]).sub.8]- chain between the polymer host and phosphorescent guest is an important design principle for achieving higher efficiencies in those electrophosphorescent organic light-emitting diodes for which the triplet energy levels of the host and guest are similar.

The total synthesis of octalactins A and B is achieved in 15 steps and 10% overall yield from commercially available materials. Key steps include the Paterson-Aldol reaction for the rapid assembly of the carbonate, methylenation of cyclic carbonate and subsequent Claisen rearrangement of the corresponding alkenyl-substituted cyclic ketene acetal to provide the core unsaturated medium-ring lactone and the use of enzyme-mediated acetate deprotection in the presence of a medium-ring lactone.

The preparation of 2,7-functionalized dibenzosilole monomers and their Suzuki cross-coupling to prepare poly(9,9-dihexyl-2,7-dibenzosilole) is reported. A comparison of the physical and optoelectronics properties of polydibenzosilole with those of an analogous polyfluorene and an alternating copolymer of the two is presented.

Research was conducted to determine a new synthesis of (-)-histrionicotoxin (HTX). A sequence of intramolecular pericyclic processes, which includes hydroxylamine-alkyne cyclization and intramolecular (3 + 2) cycloaddition, was used to develop the core ring system. Results reveal the potential of the intermediate to act as a common precursor of the other HTX family members and to provide a realistic alternative source for the products.

Organic semiconductors consisting of conjugated oligomers or polymers are suitable in photodiodes, light emitting device and other related applications because of their optoelectronic properties. An innovative approach in designing and synthesizing organic semiconductors may also enhance its thin film transistor applications. It can be achieved through the use of thiophene derivatives.

The synthesis of seven-membered lactam beta-turn mimetics, cis- (1a) and trans-N-methylamides (2a) follows with self-association of 1a in a head-to-tail order and formation of a type VI beta-turn constrained conformation of 2 in the crystal. A self-recognition is observed among the relatively unconstrained secondary amides and preoriented secondary lactam.

A Claisen realignment methodology to the key lactone is used in an enantioselective synthesis of (+)-laurencin in 26 stages from dimethyl(R)-malate. Laurencin is isolated from Laurencia glandulifera. The major processes include extremely high-yielding displacement of the secondary alcohol by bromide. The reagent controlled diastereoselective enolate oxidation and stereocontrolled introduction of the pentenynyl side chain.

Researchers applied flexible Claisen realignment technique in the preparation of the core nine-membered and unsaturated lactone 8 and its elaboration to 1, resulting in the alteration of the structure of ascidiatrienolides A to the ten-membered lactone structure 2. A crucial Stille coupling reaction was used to develop the delicate triene side chain.