214962-08-0Relevant academic research and scientific papers
The synthesis and studies towards the self-replication of bis(capped porphyrins)
Thordarson, Pall,Marquis, Annie,Crossley, Maxwell J.
, p. 1216 - 1225 (2003)
Connecting two facially-protected porphyrins was expected to lead to an equal mixture of laterally-bridged doubly-protected bis-porphyrins; one in which the two porphyrin units were protected on the same face (syn) and one with the two porphyrin units protected on opposite faces (anti). Addition of a co-factor (bidentate ligand) was expected to lead predominantly to the syn-bis-porphyrin by a templated self-replication process. This concept was explored using Baldwin's capped porphyrin. Bis(capped porphyrins) were synthesised in several steps starting from zinc(II) capped porphyrin 2. Nitration of 2 followed by reduction and photo-oxidation yields a mixture of zinc(II) porphyrin-diones 7 and 8 that can be separated by HPLC. The condensation of 2 molar eq. of zin(II) porphyrin-7,8-dione 8 with 1,2,4,-5-benzenetetramine leads to the formation of a 1 : 1 mixture of syn- and anti-dizinc(II) bis(7,8-capped porphyrins), 11 and 12, respectively, that have almost identical spectroscopic properties. These two geometric isomers were distinguished by significant differences in their molecular recognition properties. Likewise the syn- and anti-dizinc(II) bis(2,3-capped porphyrins), 9 and 10, respectively, are synthesised from the related zinc(II) capped porphyrin-2,3-dione 7, and were also identified using molecular recognition studies. The molecular recognition properties of these bis(capped porphyrins) were utilised in studies of self-replicating porphyrin systems. The results show that tetraazaanthraceno-bis-porphyrins 9-12 can catalyse their own formation but self-replication was not observed. These results highlight the potential that these interesting hosts could have as templates in supramolecular chemistry, synthesis and catalysis.
A new synthetic approach to porphyrin-α-diones and a -2,3,12,13-tetraone: Building blocks for laterally conjugated porphyrin arrays
Promarak, Vinich,Burn, Paul L.
, p. 14 - 20 (2007/10/03)
We report the first use of the Dess-Martin periodinane (DMP) for the oxidation of an arylamine to an α-dione. The methodology is illustrated by the preparation of free-base and metal chelated porphyrin-α-diones in up to 52% yield by oxidation of 2-aminoporphyrins with the DMP. We also found that DMP could be used to oxidise a 2,3-diaminoporphyrin to a porphyrin-α-dione in good yield with other free-base diaminoporphyrin isomers forming a trans-porphyrintetraone in 20% yield.
A study on the oxidation of 2-hydroxyporphyrins to porphyrin-α-diones
Beavington, Richard,Rees, Philip A.,Burn, Paul L.
, p. 2847 - 2851 (2007/10/03)
Porphyrin-α-diones have been used for the preparation of extended rigidly oriented porphyrin systems. Copper 2, free-base 3, and zinc 4 2-hydroxyporphyrins have been prepared by an improved method and treated with a range of oxidants to form the corresponding porphyrin-α-diones, 5, 6, and 7 in yields of up to 94%. We have found that the free-base 2-hydroxyporphyrin 3 was easily oxidised and usually gave the best yields of porphyrin-α-dione. In this study the most effective general oxidant was determined to be the Dess-Martin periodinane which oxidised all three 2-hydroxyporphyrins to their respective porphyrin-α-diones in good yields.
