Ring-whizzing in polyene-PtL₂ complexes revisited

• Oluwakemi A. Oloba-Whenu,
• Thomas A. Albright and
• Chirine Soubra-Ghaoui

Beilstein J. Org. Chem. 2016, 12, 1410–1420, doi:10.3762/bjoc.12.135

• ; density functional theory (DFT); hapototropic rearrangements; HOMO–LUMO interactions; polyene-ML2 complexes; ring-whizzing; Introduction Polyene–transition metal complexes were found to undergo fluxional rearrangements as early as 1956 with the preparation of Cp2Fe(CO)2 [1]. The migration of an MLn unit

• to consider a lower lying filled orbital of b1 symmetry, 7. Polyene–ML2 complexes are very fragile which in turn makes it somewhat difficult to compute the reaction path. The bond dissociation energy for ethylene–Pt(PH3)2 is only about 17 kcal/mol [23]. There are two ways in which the metal–polyene

• is Pt and a phosphine. The second method employs the use of a bidentate phosphine. In this regard we have chosen diphosphinylethane (dpe). This idea here is that the P–Pt–P angle is around 100° in polyene–ML2 complexes. Upon dissociation the 14 electron PtL2 complex strongly prefers to be linear [22