Stability and donor-acceptor bond in dinuclear organometallics CpM1-M2Cl3 (M1, M2 = B, Al, Ga, In; Cp = η 5-C5H5).

The geometries and stabilities of the dinuclear organometallics CpM1-M2Cl3 (M1, M2 = B, Al, Ga, In; Cp = η 5-C5H5) have been investigated by density functional theory (DFT) at M06 L/6-311G(d, p) levels. The nature of the donor-acceptor M1 → M2 bond was also studied based on the atoms in molecules (AIM) theory, energy decomposition analysis (EDA) and natural bond orbital (NBO) analysis. The results show that the electronegativity of the M atom determines the stability and covalent character of the dinuclear organometallics CpM1-M2Cl3. The compounds in which the M with larger electronegativity acts as the donor are more stable than in those in which it acts as the acceptor in the donor-acceptor bond, and the donor-acceptor bond has more covalent characteristics. The strength and polarity of the M1 → M2 donor-acceptor bond is determined by the periodicity of the M atom. When the period number of the M1 atom is smaller than that of M2, the strength of the M1 → M2 bond is larger than that of the M2 → M1 bond. For homonuclear dinuclear organometallics, the polarity of the M-M bond increases with increasing atomic number of the M atom. For heteronuclear complexes, the polarity of the M1-M2 bond for a given M1 also increases in the sequence of M2 = B, Al, Ga, and In. Graphic abstract Molecular graph and electron location function isosurfaces map of CpM 1 -M 2 Cl 3(small red spheres represent bond critical points).