David C. W. Reid

Controlling the Structure of Supramolecular Porphyrin Arrays

Cis/trans isomerization of the alkene in these pyridine-functionalized porphyrins results in a reorganization of the molecular architecture: the polymeric trans form of 1 transforms into the dimeric cis form when irradiated with UV light. A cis/trans mixture of isomers is obtained when the pure compounds are treated with iodine.

Diastereoselective addition of 2-trimethylsilyloxyfuran to (S)-(+)-2-(p-tolylsulfinyl)-1,4-benzoquinone

Abstract The uncatalyzed addition of 2-trimethylsilyloxyfuran to ( S )-(+)-2-( p -tolylsulfinyl)-1,4-benzoquinone 1 afforded a 3.4:1 ratio of the diastereomeric adducts 2:3 . Acetonitrile was found to be the optimum solvent whilst the use of Lewis acid catalysts afforded lower overall yields.

A convenient synthesis of trimeric porphyrins with systematically variable geometry

Abstract A facile synthesis of trimeric porphyrins is reported. The geometry of the terminal porphyrins relative to the central macrocycle can be varied without significant changes to the synthetic procedure. This procedure also enables systematic control over the metallation states of the trimeric porphyrins.

STEUERUNG DER STRUKTUR SUPRAMOLEKULARER PORPHYRINAGGREGATE

Durchcis/trans-Isomerisierung der Alkeneinheit in den pyridinfunktionalisierten Porphyrinen 1 wird ihr molekularer Aufbau reorganisiert: trans-1 liegt im Festkorper polymer vor und reagiert bei Bestrahlung mit UV-Licht zum dimeren cis-1. Durch Behandeln der reinen Verbindungen mit Iod wird ein cis/trans-Isomerengemisch erhalten.

ADDITION OF CYCLOPENTADIENE AND 2-TRIMETHYLSILYLOXYFURAN TO QUINONES BEARING A MENTHYL ESTER CHIRAL AUXILIARY

Abstract Addition of cyclopentadiene to 2-carbomethoxy-1,4-benzoquinone 9 afforded Diels-Alder adduct 10 using the Lewis acids ZnCl2 and ZnBr2 whereas the fragmenatation product 11 was the major product when using SnCl4 and TiCl4. Addition of cyclopentadiene to 1,4-benzoquinone 8 bearing a menthyl ester at C-2 afforded Diels-alder adduct 12 in moderate diastereomeric excess using ZnCl2 and ZnBr2 as Lewis acids. Use of TiCl4 and SnCl4 afforded the fragmentation product 13 also in moderate diastereomeric excess. Addition of 2-trimethylsilyloxyfuran to chiral naphthoquinone 4 and benzoquinone 8 afforded furofuran adducts 14 and 15 respectively as a 1:1 mixture of diastereomers.

Building large porphyrin arrays: pentamers and nonamers

A building block approach towards porphyrin arrays is used to construct pentameric and nonameric porphyrin arrays in one step.

The synthesis of specifically metallated heterobimetallic dimeric porphyrins

A series of conjugated mixed metal heteroporphyrin dimers has been prepared using Wittig chemistry. They can be synthesized from a double Wittig reaction between porphyrin phosphonium salts and phthalaldehydes, or from stepwise Wittig reactions. This allows both symmetrical and unsymmetrical dimers to be prepared with complete control of porphyrin metallation.

The Supramolecular Assembly of Porphyrin Arrays

The self-assembly of porphyrin arrays containing three, seven or eleven porphyrins results from the interaction of the bis-pyridyl porphyrin 1 with the zinc porphyrins 2, 3, or 4, respectively.

Spectroscopic properties of porphyrin dimers incorporating phenylenevinylene linkers

A series of free-base, zinc and mixed free-base-zinc porphyrin dimers were investigated using electrochemistry, electronic absorption, resonance Raman and emission studies. The spectroelectrochemistry of these compounds was also examined. The electronic absorption and resonance Raman data suggest that the two porphyrins in the dimer are behaving as independent chromophores with limited communication. However, emission studies show that energy transfer occurs between the two units. The linking unit is seen to have limited influence on the properties of chromophores.