Utilizing the S N Ar reaction in examining the kinetics and subphthalocyanine potential of 4-bromo-5-nitro-phthalonitrile

Phthalocyanines and subphthalocyanines with novel peripheral functional groups are highly desirable for exploring their potential for widespread use across several research fields. Synthesis of the precursor phthalocyanines has been limited due to selectivity. A precursor, 4-bromo-5-nitro-phthalonitrile, is of interest due to its potential to undergo an S N Ar reaction. The S N Ar reaction, inherently selective, can replace bromine and nitro groups with novel nucleophiles. While some substitutions have been explored, this study examined reaction kinetics to improve efficacy and assess the feasibility of synthesizing target precursor phthalonitriles. The first substitution, in place of bromine, was kinetically examined for phenol substitution to determine the optimal temperature and time to drive the reaction; 50 ° C for 2.5 hours gave the product 4-(4-(tertbutyl)phenoxy)-5-nitro-phthalonitrile. Subsequently, the second substitution of this molecule, replacing the nitro group, was kinetically examined for fluorination, yielding the best results at 80 ° C for 4 hours with 3 fluorine equivalents, giving 4-(4-(tertbutyl)phenoxy)-5-fluorophthalonitrile. Lastly, macrocycle formation was done using microwave synthesis to form Cl-(4-(tertbutyl)phenoxy) 3 (NO 3 ) 3 BsubPc and Cl-Br 3 (NO 2 ) 3 BsubPc, the former showing the potential for macrocycle formation of the substituted product, with the latter a potential for S N Ar to be used for selective macrocycle substitution. While further research on the uniformity of the kinetics is needed, baseline kinetic information was established for the S N Ar reaction in novel phthalocyanine and subphthalocyanine precursors from 4-bromo-5-nitro-phthalonitrile.