Reactivity and mechanism in the ring-opening of cyclopropylmethylplatinum(IV) complexes

The oxidative addition of cyclopropylmethyl or cyclobutylmethyl bromide to [PtMe2(bipy)], 1, bipy=2,2′-bipyridine, gave the products of trans-oxidative addition [PtBrMe2(CH2-c-C3H5)(bipy)], 2, or [PtBrMe2(CH2-c-C4H7)(bipy)], 3. These compounds are thermally stable but the complex [Pt(O2CCF3)Me2(CH2-c-C3H5)(bipy)] rearranges on heating to give the ring-opened complex [Pt(O2CCF3)Me2(CH2CH2CH=CH2)(bipy)]. Factors affecting the reactivity towards ring-opening are discussed.

Graphical AbstractThe cycloalkylmethylplatinum(IV) complexes [PtBrMe2(CH2-c-C3H5)(bipy)] and [PtBrMe2(CH2-c-C4H7)(bipy)] are thermally stable but [Pt(O2CCF3)Me2(CH2-c-C3H5)(bipy)] rearranges on heating to give the butenyl complex [Pt(O2CCF3)Me2(CH2CH2CH=CH2)(bipy)]. Factors affecting the reactivity towards ring-opening are discussed.Figure optionsDownload as PowerPoint slideResearch Highlights
► Cyclopropylmethyl and cyclobutylmethyl complexes of platinum(IV) are prepared by oxidative addition.
► These complexes are stable to ring-opening under mild conditions.
► The cyclopropylmethyl complex rearranges to the 3-butenyl isomer if a coordination site is opened up.
► The reasons for unusual stability of the ring compounds is elucidated.