The trisubstituted-triazole approach to extended functional naphthalocyanines

Abstract

Recently, a novel modular approach to octatriazole-derived phthalocyanines (Pcs; 1) was developed and optimized in our group; herein, the pool of the functional Pc materials was expanded for an additional candidate (2), a fused derivative of 1. Compared with 1, the aromaticity in 2 is extended by an additional four benzene and eight triazole rings and, in addition, the triazole units and the Pc core co-create four functional, in-plane cavities. Various methods to link the unsubstituted carbon atoms of the neighboring triazoles in 1 to afford atomically flat naphthalocyanine (Nc) analogs (2), containing eight fused triazole moieties, were studied. Several synthetic routes were designed, among them the trisubstituted-triazole approach, which was found to be the most suitable route. The crucial steps of this approach, the copper-catalyzed azide-haloalkyne cycloaddition and the intramolecular homocoupling reactions, were first studied on a model system; subsequently, this methodology was applied in the synthesis of the desired Nc 2. The increased core size and the π-electron deficient structure predict this class of Ncs to possess very strong aggregation properties. Moreover, owing to the presence of four tridentate half-cavities, the final properties of the molecule or the assembly can, in principle, be further tuned by doping with metals or guest molecules.

Catalytic and Computational Studies of N-Heterocyclic Carbene or Phosphine-Containing Copper(I) Complexes for the Synthesis of 5-Iodo-1,2,3-Triazoles

“…Similar calculations with [CuCl(IPr)] as catalyst revealed that the barrier in this case slightly higher ([11]#, 28.4 kcal/ mol), but this transition state is considerably stabilized when compared to [13]# as well as compared to its regioisomer leading to the formation of a 4-I-triazole 2a ([12]#, 34.1 kcal/ mol) (see Scheme 8 and Table 7).…”

“…Tris-triazoles, and TTTA in particular, remain the most popular ligands for this reaction, 11 and the only ones that have found application in larger systems, such as the functionalization of polymers 12 and preparation of phthalocyanines. 13 Despite its efficiency, important drawbacks remain for the general use of this family of ligands in this transformation. First of all, contrary to copper salts, tris-triazole compounds are extremely expensive.…”

5-Iodo-1H-1,2,3-triazoles as Versatile Building Blocks

“…This strategy was used as a key step in the synthesis of new planar octatriazole-derived naphthalocyanine (Nc) 124 functionalized by TIPS-protected ethynyl groups. 50 The intramolecular homocoupling was performed with 1,2bis(5-iodotriazol-4-yl)-4,5-dimethoxybenzene 122 affording the desired polyaromatic ditriazole compound 123 in 45% yield. The latter was converted into final Nc 124 in four steps (Scheme 31).…”

“…However the term CuAHAC (Cu-catalyzed azide-haloalkyne cycloaddition) is also in use. 49,50 Cu (I) R R Cu (I) "I + "-source amine…”