The nickel(II) complex of
meso-dimethylaminoprop-1-enyloctaethylporphyrin (2c) was
converted by quaternization and thermolysis into a pair of novel isomeric
macrocyclic complexes (3) and (4). These have a fused six-membered ring, and
an exocyclic double bond on the neighbouring β-position, and have been
named ‘australochlorins’. Heating these compounds in acetic acid
leads to the known nickel(II) octaethylbenzochlorin (1) and a novel
β-(1-acetoxyethyl)benzochlorin (5). Trifluoroacetic acid promotes the
regioselective formation of benzochlorin/porphyrin species from the
mononickel(II) complexes of the acrolein derivatives of
bis(octaethylporphyrinyl)ethane and trans-ethene.
The formation of complexes of f3-formyl-heptaethylporphyrin and f3-(2-formylvinyl)-heptaethylporphyrin in addition to the expected mesoformylporphyrin was detected when formylating the platinum complex of actaethyIporphyrin by the Wilsmeier reaction. A possible mechanism is proposed for the unusual formation of similar compounds.The platinum and palladium complexes of porphyrins and chlorins are of considerable interest and are used in various combinations as highly sensitive phosphorescent labels. They are applied widely as sensitive elements (sensors) in instruments for detecting oxygen and oxygen-dependent biochemical processes [2][3][4][5][6].The aim of this work was to create functionalized porphyrin phosphorescent labels capable of being bound to substrates. We have therefore attempted to synthesize the platinum and palladium complexes of octaalkylporphyrins containing promising groups and a mesoformyl group by the widely known Vilsmeier reaction (for more detail see reviews in [7, 8]).As was shown in [9], Pt complexes are the most difficult of all the metalloporphyrins to undergo the Vilsmeier reaction. Nonetheless, complex (I) was successfully obtained in very high yield (-75%) [9] by the prolonged heating (24 h) at 50~ of porphyrin (II) and the Vilsmeier complex (DMF/POCI 3) in dichloroethane, which is practically no different from the yields on formylating the classical copper and nickel complexes. However, the overall spectral characteristics (such as ~e PMR spectrum) of the isolated product were not given.
I-IV, IX, X V-VIII, XI-XVII, V R -CliO; II, XIV R -H; III, XV R -CH -N+Me2(OPOCI2)-; IV R -CH -NMe; VI R -CH -CH-CHO; VII R -CH2OH; VIII R -CH -CHCH2OH; IX R -CH -N+Me2V; X R -CH2NMe2; XI R -CH -CH-CH2OCOCH3; XII R -CHCICH3; XIII R -CH -CH2; XVI R -CH -CH--CH -N+Me2(OPOCI)2 -When repeating this reaction under the conditions given in [9] (and under other more forcing conditions) we were unable to reproduce the published results. On following the procedure of [9] precisely, the yield of complex (I) was no more than 10-25% and the yield of initial porlfhyrin (II) approached 50-60%. In addition, other reaction products were present in
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