text: The term agostic, derived from the Ancient Greek word for "to hold close to oneself", was coined by Maurice Brookhart and Malcolm Green, on the suggestion of the classicist Jasper Griffin,  to describe this and many other interactions between a transition metal and a C−H bond. Often such agostic interactions involve alkyl or aryl groups that are held close to the metal center through an additional σ-bond.
  Short interactions between hydrocarbon substituents and coordinatively unsaturated metal complexes have been noted since the 1960s. For example, in tris(triphenylphosphine) ruthenium dichloride, a short interaction is observed between the ruthenium(II) center and a hydrogen atom on the ortho position of one of the nine phenyl rings.  Complexes of borohydride are described as using the three-center two-electron bonding model.  
  The nature of the interaction was foreshadowed in main group chemistry in the structural chemistry of trimethylaluminium.