text: Green's earliest publications described metal-hydride and metal-olefin complexes, themes that he pursued throughout his career.  Many of his early contributions focused on the chemistry of molybdocene dihydride ((CH)MoH) and the related tungsten derivative.  These compounds were shown to engage in many reactions related to C-H bond activation.
  With Rooney, he was an active proponent of various mechanisms to explain stereochemistry in Ziegler–Natta polymerisation. He used metal vapour synthesis, especially for the preparation of early metal sandwich complexes. He and his students synthesised several examples of complexes exhibiting "agostic" bonds. The word was suggested to him by Jasper Griffin, professor of Classics at Balliol, whom Green asked for an appropriate Greek word to describe the close bonding phenomenon.  This work would later lead to the so-called "modified Green-Rooney mechanism" for Ziegler–Natta catalysis, wherein agostic interactions guide the stereochemistry of the alkene insertion step.  This proposal found wide acceptance.  His work on metal carbide catalysts led to the corporate spin-off company Oxford Catalysts plc, which became Velocys.
  Green along with Stephen G. Davies and Michael Mingos compiled a set of rules that summarise where nucleophilic additions will occur on pi ligands known as the Green–Davies–Mingos rules. His former doctoral students include Vernon C. Gibson.
  Green developed the covalent bond classification (CBC) method in 1995 to describe the ligands and bonding in coordination and organometallic complexes.
  Towards the end of his career Green's interests shifted to include studies of carbon nanotubes, developing methods to "uncap" (open) them, and investigating their filling with metals and with salts.