Figure 1. Atomic structure of P/AGNR-11 complex in O2 coordination. The distance between the fragments is 3.7 Å. Carbon atoms of AGNR-11 are denoted in white, carbon atoms of P are denoted in purple, hydrogen atoms are denoted in blue.
The relative energies of spin states of FeP/AGNR are presented in Table 2. It was found that among 3 possible spin states (singlet, triplet, quintet), the Fe d 6 triplet state with two unpaired electrons in dyz anddxz orbitals (Figure 2) is energetically preferable, which coincides with previous theoretical data19 at GGA PBE level of theory. The energy differences between triplet and singlet and triplet and quintet states in infrared energy region (40 and 28 kcal/mol, respectively) directly indicate possible optical activity and spin-flip transitions in FeP complex atop AGNR.
Table 2. Relative energies of the FeP complex in different spin states.