Covalently linked meso-tetraaryl triphyrin(2.1.1)-ferrocene(s) conjugates: synthesis and properties

Abstract

Functionalized meso-tetraaryl triphyrins(2.1.1) containing two meso-iodophenyl groups or a bromo group at the β-pyrrole carbon were synthesized over a sequence of steps.

Regioselective Stepwise Bromination of [14]Triphyrins(2.1.1) and Their Effects on Structural, Spectral, and Redox Properties

“…Compounds 2–7 were further characterized by 1 H, 13 C, and 1 H– 1 H COSY NMR (Figures S1–S22), and the 1 H NMR spectra of compounds 2–7 along with triphyrin(2.1.1) 1 in the selected region are presented in Figure . In the 1 H NMR spectrum, the six β-pyrrole protons of triphyrin(2.1.1) 1 showed three sets of resonances at 7.52 ppm (types d and e), 7.63 ppm (types a and b), and 8.20 ppm (types c and f) . Monobrominated triphyrin(2.1.1) 2 showed one singlet at 7.51 ppm (type b) and four doublets at 7.42 ppm (type e), 7.46 ppm (type d), 8.02 ppm (type f), and 8.14 ppm (type c) .…”

“…Triphyrin­(2.1.1) 1 is the lower member of the porphyrinoid family containing three pyrrole rings connected via four meso carbons. − Triphyrin(2.1.1) 1 is a 14π-electron aromatic macrocycle , and exhibits physicochemical properties similar to those of porphyrins. − The triphyrins(2.1.1) are monoanionic tridentate ligands with a cavity size smaller than that of 18π-tetrapyrrolic porphyrins(1.1.1.1) but have the ability to form coordination complexes like porphyrins. ,,− The recently developed (2+1) synthetic strategy reported by our group is very useful for preparing any desired meso -tetraaryl triphyrins(2.1.1) readily, and the chemistry of triphyrins(2.1.1) can now easily be exploited. The electronic properties of triphyrins(2.1.1) can be altered further upon introduction of a specific substituent(s) at the β-pyrrole carbons . One approach to the synthesis of pyrrole-substituted triphyrins(2.1.1) is by using substituted pyrroles as key precursors.…”

“…The electronic properties of triphyrins(2.1.1) can be altered further upon introduction of a specific substituent(s) at the β-pyrrole carbons. 20 One approach to the synthesis of pyrrolesubstituted triphyrins(2.1.1) is by using substituted pyrroles 21 as key precursors. However, the substituted pyrroles are not easily accessible.…”

“…However, the substituted pyrroles are not easily accessible. Alternately, functionalized triphyrins(2.1.1) such as halogenated triphyrins(2.1.1) 20 can be used to synthesize pyrrole-substituted triphyrins(2.1.1). However, there has been no report of the regioselective halogenation on triphyrins(2.1.1) to understand the effect of halogen substitution at the pyrrole carbons of triphyrin(2.1.1) on the spectral, structural, photophysical, and redox properties and to use the halogenated triphyrins(2.1.1) as key synthons for the synthesis of new types of sterically crowded pyrrole-substituted triphyrins(2.1.1).…”

Switching of Aromatic Free Base Triphyrin(2.1.1) to Antiaromatic Phosphorus(V) Complexes of Triphyrin(2.1.1)

“…Although the triphyrin(2.1.1)­s such as meso -tetraaryl bicyclo[2.2.2]­octadiene­(BCOD)-fused-triphyrin(2.1.1)­s and meso -tetraaryl triphyrin(2.1.1)­s were initially formed serendipitously, researchers have optimized the conditions to obtain triphyrin(2.1.1)­s in good yields and demonstrated that the triphyrin(2.1.1)­s are indeed good coordinating ligands by synthesizing Ru­(II), Re­(I), Mn­(I), Fe­(II), Pd­(II), Pt­(II), Pt­(IV), Ir­(III), and B­(III) triphyrin(2.1.1) − complexes (Chart ). Recently, we established a simple and straightforward [2 + 1] condensation method for the synthesis of β-free meso -tetraaryl [14]­triphyrin(2.1.1)­s 1–3 in good yields using readily available precursors as shown in Scheme . − Our approach now would allow to synthesize any desired meso -tetraaryl triphyrin­(2.1.1)­s in reasonable yields.…”