Pyrrole‐Modified Subporphyrins Bearing a Sulfur‐Containing Heterocyclic Unit

Abstract

As new pyrrole‐modified subporphyrins (PMSubPs) bearing a sulfur‐containing heterocyclic unit, dithiazolosubporphyrin 5, dithiazinosubchlorin 6, and oxodithiazinosubchlorin 7 were synthesized from α‐fluorosubchlorophin 2 via α’‐selective nitration with Cu(NO3)2 followed by double SN2 reaction with methyl 3‐mercaptopropionate as a key step. Oxidation of 5 with H2O2 in the presence of a tungsten catalyst afforded S,S‐dioxodithiazolosubporphyrin 8 and nitration of 5 with Cu(NO3)2·3H2O gave β‐nitrodithiazolosubporphyrin 9 or β,β‐dinitrodithiazolosubporphyrins 10a and 10b depending on reaction conditions. In the solid‐states, the dithiazole units in 8 and 9 are almost planar but the dithiazine unit in 6 and the 2‐oxodithiazine unit in 7 are non‐planar. Compared to subchlorophin 1, dithiazolosubporphyrin 5 possesses a significantly reduced diatropic ring current and a greatly perturbed absorption spectrum showing largely split Q‐like bands at 501 and 660 nm. These perturbed electronic and optical properties of 5 are considerably attenuated in 6 and 7 and completely vanished in 8, suggesting the importance of disulfide bond for the large perturbation.

Recent advances in subphthalocyanines and related subporphyrinoids

“…The latter was transformed into the Subseco-chlorin 656 , and subsequently decarboxylated to 657 . 614 Most importantly, the dioxo- and Subseco-chlorins have been used in a variety of chemical transformations to give different core modified SubP analogues, 614 such as subporpholactone 664 , subporpholactama 665 , imidazoloSubP 666 , 662 dithiazoloSubchlorin 667 , dithiazinoSubchlorin 668 , oxodithiazinoSubchlorin 669 , dioxodithiazinoSubchlorin 670 , 663 and quinoxalino-fused SubPs 671–674 , 664 as described in Scheme 59 and Table 28.…”

Mono- and Dinitro-BN-Naphthalenes: Formation and Characterization

“…BN aromatics have been widely investigated in recent years since the materials pos sess attractive physical and chemical properties and hold potential applications in the light-emitting polymer [1][2][3][4][5][6][7][8][9][10][11][12], semiconductor [13][14][15][16][17], and other research fields [18][19][20][21][22][23][24][25][26][27][28][29] however, there have been relatively few reports on the synthesis of nitrated BN aromatics Thus far, only five mononitro-BN aromatics have been reported [30,31]. Dewar and their co-workers [30, in 1959, reported the first nitration of a BN aromatic, BN-phenanthrene (BNP), yielding a mixture of mononitro-substituted BNPs (1).…”

“…BN aromatics have been widely investigated in recent years since the materials possess attractive physical and chemical properties and hold potential applications in the light-emitting polymer [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ], semiconductor [ 13 , 14 , 15 , 16 , 17 ], and other research fields [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ]; however, there have been relatively few reports on the synthesis of nitrated BN aromatics. Thus far, only five mononitro-BN aromatics have been reported [ 30 , 31 ].…”