Boron(III) Carbazosubphthalocyanines: Core‐Expanded Antiaromatic Boron(III) Subphthalocyanine Analogues

Abstract

Condensation of 1,8-diamino-3,6-dichlorocarbazole with aseries of disubstituted 1,3-diiminoisoindolines,followed by treatment with BF 3 ·OEt 2 led to the formation of the corresponding core-expanded boron(III) subphthalocyanine analogues.T hese air-stable p-conjugated boron(III) carbazosubphthalocyanines possess two boron-containing seven-membered-ring units and a16p-electron skeleton, and represent the first examples of antiaromatic boron(III) subphthalocyanine analogues as supported by spectroscopic and theoretical studies.T he molecular structure of one of these compounds was unambiguously determined by single-crystal X-ray diffraction analysis.I nc ontrast to typical boron(III) subphthalocyanines,whichadopt acone-shaped structure,the p skeleton of this compound is almost planar.

Recent advances in subphthalocyanines and related subporphyrinoids

“…Carbazosubporphyrazines 321–324 (Scheme 28) contain a 16 π-electron, antiaromatic core, 550 which has been assembled in two steps. The first step consists in a condensation reaction in ethanol of a diiminoisoindoline derivative and a carbazole-1,8-diamine, in a 2 : 1 ratio, to afford a three-unit intermediate 317–320 .…”

“…547 More recently, one of the pyrrole rings has been replaced by azepine (314, 315 and 316) 548,549 and carbazole rings (317-320). 550 314 and 315 contain 14 p-electron aromatic cores, which have been assembled in crossover cyclotrimerization reactions of tetrafluorophthalonitrile with 2,2 0 -biphenyldicarbonitrile and 4,5-phenan- threnedicarbonitrile, respectively, in the presence of BCl 3 at 180 1C in 1-chloronaphthalene (Scheme 26). 548 Under these conditions, an unprecedented replacement of the axial chloride by fluoride took place, presumably sourced from tetrafluorophthalonitrile.…”

Recent Advances in Heterocyclic Nanographenes and Other Polycyclic Heteroaromatic Compounds

“…In 2019, Kobayashi and Ng reported a series of air-stable boron(III) carbazosubphthalocyanines, which can be seen as core-expanded subphthalocyanine (SubPc) analogues. 625 The synthesis of 333.3a – d was achieved by the condensation of 1,3-diiminoisoindolines 333.1a – d and diamine 333.2 , followed by boron-induced complexation and cyclization ( Scheme 333 ). The choice of BF 3 ·Et 2 O instead of other Lewis acidic boron sources such as BCl 3 and BBr 3 was needed to obtain the desired product, stabilized by the axial fluoride ligand.…”

“…In 2019, Kobayashi and Ng reported a series of air-stable boron­(III) carbazosubphthalocyanines, which can be seen as core-expanded subphthalocyanine (SubPc) analogues . The synthesis of 333.3a – d was achieved by the condensation of 1,3-diiminoisoindolines 333.1a – d and diamine 333.2 , followed by boron-induced complexation and cyclization (Scheme ).…”

“… a Reagents and conditions: (a) (1) EtOH, reflux, (2) BF 3 ·Et 2 O, DBU, 1-chloronaphthalene, 150 °C. …”