The electronic structures of Co and Ni tetraazaannulenes

Jing Liu; Jie Xiao; Seok-Bong Choi; P Jeppson; L Jarabek; Ya B Losovyj; A N Caruso; P A Dowben

doi:10.1021/jp0656126

The electronic structures of Co and Ni tetraazaannulenes

J Phys Chem B. 2006 Dec 28;110(51):26180-4. doi: 10.1021/jp0656126.

Authors

Jing Liu¹, Jie Xiao, Seok-Bong Choi, P Jeppson, L Jarabek, Ya B Losovyj, A N Caruso, P A Dowben

Affiliation

¹ Department of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience, Behlen Laboratory of Physics, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0111, USA.

PMID: 17181273
DOI: 10.1021/jp0656126

Abstract

We compare the electronic structure of two metal-centered tetramethyldibenzo-tetraazaannulene (TMTAA) macrocyclic complex molecules: 5,7,12,14- tetramethyl-2,3:9,10-dibenzo[b,i]-1,4,8,11-tetraazacyclotetradecine nickel (II) and 5,7,12,14-tetramethyl-2,3:9,10-dibenzo[b,i]-1,4,8,11-tetraazacyclotetradecine cobalt (II). The experimental gap between the highest occupied molecular orbital to the lowest unoccupied molecular orbital for both molecules, obtained from combined ultraviolet photoemission and inverse photoemission studies, is close to the value of 6.6 eV expected from simple model calculations, but with the Fermi level placed closer to the lowest unoccupied molecular orbital. While both the Co(II) (s = 1/2) and Ni(II) (s = 0) TMTAA molecular electronic structures are very similar, the Ni(II) adopts a high-symmetry molecular configuration upon adsorption, with a strong preferential orientation.