Millagahamada G. Ranasinghe

Long-lived photoinduced charge separation in a bridged C60-porphyrin dyad

Abstract Long-range photoinduced energy and electron transfer have been investigated in a novel dyad containing a zinc tetraarylporphyrin (PZn) donor and a C60 acceptor separated by a saturated norbornylogous bridge nine sigma bonds in length (PZn-9σ-C60). In non-polar solvents singlet-singlet energy transfer from PZn to C60 is observed but in benzonitrile efficient (> 90%) charge separation occurs with a rate constant of 1 × 1010 sec−1 to yield PZn.+-9σ-C60.−. The charge separated state exhibits a remarkably long lifetime for a dyad of 420 ns. This behaviour is discussed with reference to the energetics, dynamics and orbital symmetry properties of the states involved.

A synthetic strategy for the construction of a novel series of buckminsterfullerene (C60) Ball-and-Chain molecules containing the porphyrin chromophore

Abstract A general method is described for synthesizing rigid “Ball-and-Chain” bichromophoric systems of the type C 60 -{rigid bridge}-porphyrin 2 .

MONO- AND DIALKYLATION OF ISOPROPYL PHOSPHINATE-A SIMPLE PREPARATION OF ALKYLPHOSPHINATE ESTERS1

Abstract Base-catalysed alkylation of isopropyl phosphinate with primary alkyl halides under mild conditions affords the corresponding alkyl phosphinate esters in fair to excellent yields.

Phosphitylation via the Mitsunobu reaction

Treatment of a dialkyl phosphite with triphenylphosphine and diisopropyl azodicarboxylate in toluene, followed by addition of an alcohol, results in the formation of the corresponding trialkyl phosphite. Similarly, dialkyl phosphonites can be synthesised from monoalkyl phosphites (alkyl phosphinates).

Synthesis of high refractive index acrylic copolymers

A series of brominated carbazole-containing monomers with a polymerizable acrylic or methacrylic functionality were synthesized and characterized. These monomers were polymerized thermally and characterized by differential scanning calorimetry (DSC) and refractive index via Brewsters angle. The monomer 4-(1,3,6,8-tetrabromo-9-carbazolyl)-1-butyl acrylate (4b) was copolymerized with methyl methacrylate (M2) yielding the reactivity ratiosr1= 1.08 and r2= 0.93; these values were used in the Skeist procedure to predict compositional drift with conversion. The Alfrey–Price Q and e values for (4b) were 0.86 and 0.46, respectively. The copolymers were all colourless and transparent, despite the absence of an azeotrope for this comonomer pair, and their refractive indices were found to lie between those of the constituent homopolymers. Copolymers rich in methyl methacrylate (MMA) were found to be soluble, yet those rich in 4b were found to be intractable.

A STEREOSELECTIVE SYNTHESIS OF TWO 2-DEOXY-3-PHOSPHASUGARS EPIMERIC AT PHOSPHORUS

Abstract A synthetic route to 2-deoxy-3-phosphasugar derivatives utilising a stereoselective addition of a phosphinate to an aldehyde is described.