Tellurophene-Containing Core-Modified Pentaphyrin(2.1.1.1.1)s

Abstract

Various core-modified tellurophene-containing pentaphyrin(2.1.1.1.1)­s were synthesized via (3 + 2) condensation of 16-telluratripyrrane with different heterodiols under mild acid catalyzed conditions in 5–12% yields. The formation of pentaphyrin (2.1.1.1.1) with a N2O2Te core was not successful due to its inherent instability. The new pentaphyrins were characterized and studied by HR-MS, 1D and 2D NMR, X-ray crystallography for one of the pentaphyrins, absorption and DFT/TD-DFT techniques. The NMR studies indicated their nonaromatic nature. The X-ray structure obtained for pentaphyrin(2.1.1.1.1) with N4Te core revealed that the macrocycle exists in a highly distorted nonplanar structure. The DFT studies showed that the macrocycles are nonaromatic and exists in highly distorted nonplanar geometry. Furthermore, as the core heterocyclic groups at ethene moiety were changed from pyrrole to furan to thiophene to benzene, the macrocycles tended toward more planar structures. The absorption spectra of pentaphyrins showed one strong sharp band in the region of 450–540 nm along with a broad band in the region of 700–800 nm. The pentaphyrin(2.1.1.1.1) with N4Te core upon protonation showed distinct color change in solution and large bathochromic shifts in absorption bands with an absorption in the NIR region.

Synthesis and Studies of Mono‐functionalized Telluradithiasapphyrins and Covalently Linked Porphyrin‐ Telluradithiasapphyrin Dyads

“…Tellurophene containing porphyrinoids which resulted by replacing one or more pyrrole ring(s) of porphyrinoids are unique and quite different in terms of structure, reactivity, and coordination chemistry from other chalcogenide substituted porphyrinoids. [1][2][3][4][5][6][7] This is attributed to the large size of the tellurium atom and because of this, the distance between tellurium atom and the atom situated trans to it inside porphyrinoid core reduced. This in turn resulted in interaction between atoms inside porphyrinoid core and consequently the properties of telluraporphyrinoids are significantly altered.…”

“…Recently, our group reported synthesis of tellurophene contain-ing porphyrins and expanded porphyrins. [3][4][5][6][7] One of such tellurophene containing expanded porphyrins is meso-tetraaryl telluradithiasapphyrin 1 which is 22π aromatic macrocycle and exhibits very interesting physico-chemical properties. [4] We removed Te atom from meso-tetraaryl telluradithiasapphyrins to generate vacatadithiasapphyrins 2 and explored their strutural, spectral, electrochemical, and coordination properties.…”

Pd(ii), Ni(ii), and Cu(ii) complexes of α,α′-ditolylmethanone dipyrroethene

“…1) as a key precursor for the synthesis of triphyrins [23][24][25][26][27] and expanded porphyrinoid macrocycles. [28][29][30] The α,α′-ditolylmethanone dipyrroethene 4 exists in E-and Z-forms but can be used directly, without separating the isomers, for the synthesis of porphyrinoid macrocycles. [23][24][25][26][27][28][29][30] Interestingly, the ligand 4 (Fig.…”

“…[28][29][30] The α,α′-ditolylmethanone dipyrroethene 4 exists in E-and Z-forms but can be used directly, without separating the isomers, for the synthesis of porphyrinoid macrocycles. [23][24][25][26][27][28][29][30] Interestingly, the ligand 4 (Fig. 1) can also be used as a dianionic tetradentate ligand to form square planar coordination complexes.…”

Vacatadithiasapphyrins: Synthesis, Structure, and Spectral and Redox Properties

“…In recent times, we have reported some examples of tellurophene-containing porphyrinoids and among these, the [22]­telluradithiasapphyrins 10­(a–d) exhibit more interesting structural and electronic properties. − We thought of synthesizing [22]­vacatadithiasapphyrins by extrusion of Te from [22]­telluradithiasapphyrins 10­(a–d) since these macrocycles 10­(a–d) are aromatic and showed very interesting structural, spectral, and redox properties and anticipated that such novel properties would be retained in [22]­vacatadithiasapphyrins (Chart ). Our attempts were successful in achieving stable aromatic vacatadithiasapphyrins.…”