Density functional theory calculations on the electronic and optical properties of 2,7,12,17-tetrakis(pinacolatoboryl) porphyrin and its derivatives

Abstract

In order to explore novel porphyrins with excellent conductivity and selective light absorption, the influence of metal atom embedding and functional group attachment on the electronic and optical characteristics of porphyrins has been concerned. In this study, the structures, electronic, and optical properties of the 2,7,12,17-tetrakis(pinacolatoboryl) porphyrin and its derivatives have been investigated using density functional theory (DFT). The N–Ni–N bond angles of the derivatives are mostly close to 90.00°, with the exception of the N6-Ni5-N9 bond angle (45.09°) for the Ar and Br co-attached porphyrins (5 porphyrins). Additionally, the calculated ruffling displacements (druf) for the 2, 3, 5, and 6 porphyrins are 1.2691 Å, 1.1427 Å, − 1.2561 Å, and 0.5139 Å, respectively. The lowest frequency out-of-plane (oop) normal deformation of the 4 porphyrins is a waving motion with a displacement of 0.0532 Å. The energy gaps for the 1–6 porphyrins are similar, ranging from 4.44 to 4.80 eV. The presence of Br atoms promotes the Hirshfeld charge transfer between the C atoms within the macro-cycle of the Ar and Br co-attached porphyrins and the Ar functional groups. Furthermore, the Ar attached porphyrins exhibit a 20-nm red-shift compared to the Bpin-attached porphyrins. The addition of Br leads to an additional about 6-nm red-shift compared to the Ar-attached porphyrins. This is advantageous for expanding the application of porphyrins in industrial fields such as sensors and photocatalysts.