Theoretical Study on Inverse Sandwich Complexes [E-C5−nH5−nNn-E]+ and [E-C5−nH5−nPn-E]+ (n=1, 2, 3; E=Al, Ga, In, Tl)

Abstract

The inverse sandwiches [E-C5−nH5−nNn-E]+ and [E-C5−nH5−nPn-E]+ (n=1, 2, 3; E=Al, Ga, In, Tl) with low-valent boron group elements are studied. The (η5, η5) coordinated inverse sandwich [E-C5−nH5−nNn-E]+ is unstable in energy or nonexistent. However, the (η5, η5) coordinated [E-C5−nH5−nPn-E]+ is not only stable in energy, but also stable against dissociation. The dissoction stability [E-C5−nH5−nPn-E]+ with the same E element decreases as the number n increases, while for the certain n number, the dissociation energies with different E elements are close to each other. [E-C4H4P-E]+ has similar dissocition stability to the well-known [E-C5H5-E]+. The inteaction between C5−nH5−nPn and low-valent E element is mainly ionic. Since lone pairs of electrons locate on both E and P atoms, the (η5, η5) coordinated inverse sandwich [E-C5−nH5−nPn-E]+ would act as multi electron-donors.