Theoretical Analysis on Molecular Magnetic Properties of N-Confused Porphyrins and Its Derivatives

Abstract

We have theoretically investigated the magnetic properties of N-confused porphyrin (NCP), tetraphenyl-Nconfused porphyrin (TPNCP) and their substituted derivatives with O, S and Se heteroatoms (2ONCP, 2STPNCP, 2SeNCP, 2OTPNCP, etc.) by using DFT method. In the minimum energy structures of the 2OTPNCP, the two couples opposite phenyl substitutes are staggered. In the case of TPNCP, 2STPNCP and 2SeTPNCP, two phenyls being respectively close to or opposite to N-confused pyrrole are found to be pointed the same direction, whilst others are in the opposite direction. Based on the equilibrium structures, the 1 H chemical shifts and nucleus-independent chemical shifts (NICS) are calculated in this paper. The π current density being induced by the tridimensional perpendicular magnetic field transmits the inner section of the pyrrole segments for NCP and TPNCP. As for their substituted derivatives with O, S and Se atoms, the current path passes through the outer section of the two heterorings. The NICS values at the ring critical points of the heterorings are much lower (in absolute value) than those of which is at the center of an isolated pyrrole molecule. The 1 H NMR for β H atoms of the heterorings decreases from O, S to with Se.

Theoretical analysis of expanded porphyrins: Aromaticity, stability, and optoelectronic properties

“…It can be concluded from the aforementioned discussions that the aromaticity of all molecules increase in the order of 7 < 8 < 5 < 6 < 3 < 4 < 1 < 2 . We note that the NICS (1) value of porphyrin is only -14.98 ppm ( Wei et al, 2012 ). This indicates that all designed molecules have strong aromaticity than porphyrin.…”

Stability, Aromaticity, and Photophysical Behaviors of Macrocyclic Molecules: A Theoretical Analysis

“…It can be concluded from the abovementioned discussions that all molecules have strong aromaticity in the order of 1 < 2 < 3 . And the NICS value of porphyrin is −14.98 ppm (Wei et al, 2012 ). This also shows that 1 , 2 , and 3 have good aromaticity than porphyrin.…”

Creation from Confusion and Fusion in the Porphyrin World─The Last Three Decades of N-Confused Porphyrinoid Chemistry

“…Notably, the combination of confusion and NH tautomerism offers a rich pool of π-conjugated macrocyclic compounds, all of which could provide unique coordination environments for metal centers. The resulting pool of porphyrinoids continues to stimulate the interest of theoretical chemists, and a large number of theoretical calculations about their structures, electronic states, and photophysical properties were conducted, offering many profound insights into porphyrin chemistry. − …”