One‐Pot Synthesis of Contracted and Expanded Porphyrins with meso‐CF₃ Groups

Abstract

Corrole and sapphyrin with the smallest meso-substituents reported so far were prepared in a one-pot synthesis that relies on a non-aldehydic precursor for introducing CF groups. The substantial amounts of products obtained by this facile pathway allowed for the full characterization of 5,10,15-tris(trifluoromethyl)corrole, the access to a variety of stable chelates thereof and investigations that disclose the unique structural and chemical properties induced by the CF substituents. The novel 5,10,15,20-tetra(trifluoromethyl)sapphyrin undergoes only single protonation, which according to its crystal structure is stabilized by favorable non-bonding F/H interaction between the meso-CF and the inverted pyrrolic NH.

Rhodium Complexes of a New‐Generation Sapphyrin: Unique Structures, Axial Chirality, and Catalysis

“…The synthetic details for the preparation of H 3 (tfs) , H 3 (tpfs) , Rh(tpfc)(py) 2 , and Rh(H 2 tpfs)(CO) 2 were provided in previous publications …”

“…Truly surprising is that there is just a single report in which metal complexes of sapphyrins are claimed to be useful for catalysis, which was one motivation for the current research . The other was that we recently gained access to the first meso ‐alkyl‐substituted sapphyrin, which exhibited several novel features, and it was hence of interest to see if and how they may come into effect in practical applications. We now report the results obtained for five rhodium complexes chelated by sapphyrins and corroles with C 6 F 5 or CF 3 groups on their meso ‐C atoms (Scheme ).…”

One‐Pot Synthesis of Contracted and Expanded Porphyrins with meso‐CF3 Groups

“…[20] Thelarger amounts of available material also allowed for an investigation of the green product (80 mg, 1.7 %) that accompanied TFC-H 3 in all the syntheses.B ased on NMR examinations,i tw as identified as as apphyrin with four CF 3 substituents in its meso-C positions (Scheme 1, 2-H 3 ). [35] spectrum revealed as harp CH doublet at very high field (À2.11 ppm), ab road NH singlet at 12.67 ppm, and four CH resonances between 10.40 and 9.59 ppm (Figure 2c). The synthetic route for obtainingTFC-H 3 and 2-H 3 ,a nd the protonation events of the latter.T he inverted pyrrole ring and the C 2 symmetry axis present in 2-H 3 are emphasized.…”

“…Thef ive-coor- [35] dinate Ga(TFC)(py) complex displays ad omed structure (Figure 3a)with the Ga ion displaced 0.3704 out of the N 4 plane,aGa À N pyrrole average bond length of 1.944(2) ,a nd aconsiderably longer Ga À N py bond length of 2.044 (2) .The binding of the axial ligand is still strong enough to be clearly observed in the 1 HNMR spectrum (Supporting Information, Figure S4);a nd all of the above features are very similar to those reported for Ga(TPFC)(py). Thef ive-coor- [35] dinate Ga(TFC)(py) complex displays ad omed structure (Figure 3a)with the Ga ion displaced 0.3704 out of the N 4 plane,aGa À N pyrrole average bond length of 1.944(2) ,a nd aconsiderably longer Ga À N py bond length of 2.044 (2) .The binding of the axial ligand is still strong enough to be clearly observed in the 1 HNMR spectrum (Supporting Information, Figure S4);a nd all of the above features are very similar to those reported for Ga(TPFC)(py).…”

“…a) Topview of the crystal structure of TFA/2-H 3 with highlights on the FÀHC and FÀHN distances;[35] b) Side view,w ith emphasis on the dihedral angle of the mostly deviating pyrrole ring and the hydrogen bonding interactions (by a d e Hirshfeld surface); c) The 1 HNMR spectrum of 2-H 3 (in CDCl 3 ), with emphasis on the CH and NH resonances of the inverted pyrrole ring (marked III in the drawing).…”