Structure and Electronic Properties of Metal Di-(4-thiophenyl)-porphyrin

Abstract

The geometry and electronic structures of metal 5, 15-di-(4-thiophenyl)-porphyrin (MDTP) have been investigated using first-principles calculations. Several metal atoms, including Cr, Mn, Fe, Co, Ni, Cu and Zn, have been selected. It has been found that the dihedral angle between porphyrin and thiophenyl planes is close to the perpendicular, which means that the π conjugation in whole MDTP molecules is broken. The most stable spin configurations of Cr, Mn, Fe, Co and NiDTPs are S = 2, 5/2, 1, 1/2 and 0, respectively. Analysis of metal 3d-orbital splitting in Zn and NiDTP have shown that in the case of NiDTP, the out-of-plane interaction between metal 3d-orbitals and π orbital of porphyrin is larger than that in the case of ZnDTP. The results suggest that the Ni metal will enhance the conductance of DTP because transport properties in molecular systems have strong relations to the molecular π orbital.

Keywords:

• Metal porphyrin
• Transport properties
• First-principles calculations
• 3d-orbital splitting

Acknowledgements

The authors would like to express their sincere thanks to the staff of the Center for Computational Materials Science of the Institute for Materials Research, Tohoku University for their continuous support of the SR8000 supercomputing facilities. This study was performed through Special Coordination Funds for Promoting Science and Technology from the Ministry of Education, Culture, Sports, Science and Technology of the Japanese Government.