A theoretical investigation of the nonrigid six-coordinate compounds [Mo(R)F5], [W(R)F5], and related compounds

Density functional calculations for M(CH3)F5], M(CF3)F5], M(CH3S)F5], and M(CF3S)F5] (M=Mo, W) show that they are expected to be nonrigid molecules, with energy barriers for the octahedral-trigonal-prismatic interchange as low as 7.2 kJ mol(-1). The ground state for the CH3- and CF3- compounds is trigonal prismatic, for the CH3S- and CF3S- compounds, (distorted) octahedral. All calculated compounds M(C6F5)nF(6-n)] (M=Mo, W) have a trigonal-prismatic ground state, whereas the situation for M(C6H5)nF(6-n)] (M=Mo, W) is more complex.