Transition metal carbon quadruple bond: viability through single electron transmutation

Quadruple bonding to main group elements is extremely rare although they have four valence orbitals accessible for bonding. Here we report the unprecedented quadruple bonding between a carbon atom and a transition metal fragment Fe(CO) 3 based on high level theoretical calculations. Various bonding analyses reveal the unprecedented nature of the C&z.qbd;Fe quadruple bonding interaction. The validity of the single electron transmutation concept has been tested which fruitfully reproduces the structural and bonding similarities between the two neighbours in the periodic table. Quadruple bonding to main group elements is extremely rare although they have four valence orbitals accessible for bonding.