Regioselective 2,3-disubstituted porphyrins: synthesis, spectral, structural and electrochemical properties

Abstract

A series of regioselective β-disubstituted meso-tetraphenylporphyrins, H2TPP(X)2 where X = methyl (CH3), phenyl (Ph) and phenylethynyl (PE) as well their metal complexes (Cu(II), Co(II), Ni(II) and Zn(II)) were synthesized and...

Single Pyrrole Unit Functionalized Electron Deficient Porphyrins and Their Metal Complexes: Synthesis, Structural, Spectral and Electrochemical Properties

“…With a favorable yield to a maximum of 85 %, this regioselective dibromo precursor was successfully synthesized from β-mononitro-dibromo-meso-tetraphenylporphyrins (H 2 TPP(NO 2 )Br 2 via modified literature methods. [76,77] The copper metalated derivative of 2,3-dibromo-5,10,15,20-tetraphenylporphyrins (CuTPPBr 2 ) was utilized in a Pd-catalyzed trifluoromethylation with Chen's reagent (FSO 2 CF 2 CO 2 Me) to produce Cu(II) 2,3-bis(trifluoromethyl)-mesotetraphenylporphyrin (CuTPP(CF 3 ) 2 ) with a yield of 92 %. Cu(II) 2,3-dicyano-meso-tetraphenylporphyrin (CuTPP(CN) 2 ) was syn-thesized from CuTPP(Br) 2 by refluxing with copper(I) cyanide (CuCN) in quinoline with a yield of 80 % as demonstrated in Scheme 1.…”

“…The regioselective 2,3‐dibromo‐meso‐tetraphenylporphyrins (H 2 TPPBr 2 ) is an incredibly stable precursor in synthetic porphyrin chemistry and may be employed to wide range cross coupling and substitution reactions. With a favorable yield to a maximum of 85 %, this regioselective dibromo precursor was successfully synthesized from β ‐mononitro‐dibromo‐ meso ‐tetraphenylporphyrins (H 2 TPP(NO 2 )Br 2 via modified literature methods [76,77] . The copper metalated derivative of 2,3‐dibromo‐5,10,15,20‐tetraphenylporphyrins (CuTPPBr 2 ) was utilized in a Pd‐catalyzed trifluoromethylation with Chen's reagent (FSO 2 CF 2 CO 2 Me) to produce Cu(II) 2,3‐bis(trifluoromethyl)‐ meso ‐tetraphenylporphyrin (CuTPP(CF 3 ) 2 ) with a yield of 92 %.…”

“…Versatile precursor, H 2 TPPBr 2 was synthesized in good yields by modified synthetic methods documented in the literature. [76,77]…”

“…[8,31] Reductive denitration of H 2 TPP(NO 2 )Br 2 yielded regioselective 2,3-dibromo-5,10,15,20-tetraphenylporphyrin (H 2 TPPBr 2 ). [76,77] The cyanation of the nickel complex of H 2 TPPBr 2 was attempted using CuCN in quinolone to yield NiTPP(CN) 2 , however, the synthesis of highly electron deficient free base regioselective 2,3-dicyano-meso-tetraphenylporphyrin and other metal complexes remains unexplored. [76] A mixture of partially β-trifluoromethylated-meso-tetraphenylporphyrins [H 2 TPP(CF 3 ) n (where n = 1-4), was reported by Dolphin et al with lower yields of the order of 2-8 % for mixture of β-trifluoromethylated products.…”

“…This approach yielded β ‐push‐pull porphyrins with a combination of different substituent patterns [8,31] . Reductive denitration of H 2 TPP(NO 2 )Br 2 yielded regioselective 2,3‐dibromo‐5,10,15,20‐tetraphenylporphyrin (H 2 TPPBr 2 ) [76,77] . The cyanation of the nickel complex of H 2 TPPBr 2 was attempted using CuCN in quinolone to yield NiTPP(CN) 2 , however, the synthesis of highly electron deficient free base regioselective 2,3‐dicyano‐meso‐tetraphenylporphyrin and other metal complexes remains unexplored [76] …”