Inverted Sapphyrin:  A New Family of Doubly N-Confused Expanded Porphyrins

Abstract

The synthesis of an inverted, methoxylated sapphyrin derivative is described. This system, wherein inversion of pyrrolic nitrogen atoms is configurationally enforced via the use of a 3,3‘-bipyrrolic precursor, displays what is best described as “weak aromaticity” as judged from its spectroscopic features and supporting theoretical calculations.

Figure Eights, Möbius Bands, and More: Conformation and Aromaticity of Porphyrinoids

“…Consequently, geometry-based indexes of aromaticity [117] become particularly useful in quantitative analysis of such systems, as has been proven for porphyrins [108] and some porphyrin analogues. [103,[118][119][120][121][122][123] Typically used methods are the harmonic oscillator model of aromaticity (HOMA), [103,[120][121][122][123][124] known to give good correlation with magnetic criteria, and the harmonic oscillator stabilization energy method (HOSE) enabling estimation of canonical weights. [118,119,125] …”

N‐Confused and N‐Fused meso‐Aryl Sapphyrins

“…[5,10] For 1, in accordance with the tautomeric structure above, a 22p aromatic system is indicated by the difference in the chemical shifts between the outer and inner protons (Dd = 12.6 ppm) in 1, which is slightly less than that of the all-aza-meso-tetrakis(pentafluorophenyl)sapphyrin (Dd = 14.8 ppm), [11] but much higher than that of N-confused dithiasapphyrin (Dd = 7.06 ppm) [10] and the recently reported inverted b-alkylated sapphyrin (Dd = 4.79 ppm). [13] Reflecting the aromatic nature of 1, two intense bands are observed in the Soret region at 395 and 497 nm in the absorption spectrum, and four small Q-type bands are observed at 625, 679, 750, and 871 nm (Figure 1).…”

Double Properties of Novel Acylhydrazone Nanomaterials Based on a Conjugated System: Anion Binding Ability and Antibacterial Activity

“…So far, the focus has mainly been on the design of a receptor that has the ability to recognize and bind the biologically important anions. The binding units in receptors are important and often composed of amide [15], urea [16], hydroxyl [17,18], and pyrrole [19] owing to their capacity to perform as hydrogen donors. However, the literature has reported few cases of acylhydrazone (NHCO) serving as an anion binding site.…”