Octacoordinate carbon atom in tetra(metalloamino)methanes CN4M4 (M = Be, Mg, Ca): Quantum-chemical investigation

Quantum-chemical methods, ab initio [MP2(full)/6-311+G**] and density functional theory (B3LYP/6-311+G**), were applied to investigation of the electronic and spatial structure of tetraaminomethane derivatives CN 4 M 4 (M = Be, Mg, Ca) both in classic and nonclassic isomeric forms. For all compounds structurally stable nonclassic isomeric forms were found with an octacoordinate carbon atom. The CN 4 Be 4 is energetically most stable in a classic structure with a tetracoordinate carbon atom, whereas CN 4 Mg 4 and CN 4 Ca 4 are more stable in nonclassic structures with an octacoordinate carbon center.