Reversible C–C bond formation at a triply cyclometallated platinum(iv) centre

Abstract

Reversible C–C bond formation follows first order kinetics and proceeds via a triply cyclometallated Pt(iv) centre.

A novel Pt(iv) mono azido mono triazolato complex evolves azidyl radicals following irradiation with visible light

“…We were unable to find reports of any directly comparable systems involving cyclisation of a ligand which is attached to a Pt centre, rather than bond breaking/formation at the metal centre itself. However, the activation barrier appears to be in the appropriate range for a reversible transformation at a metal centre on the NMR timescale, and values reported for reversible bond formation and breakage at a Pt IV centre 24 and rotation of a Pt II -allene complex 25 are consistent with our findings.…”

Luminescent Platinum(IV) Complexes Bearing Cyclometalated 1,2,3‐Triazolylidene and Bi‐ or Terdentate 2,6‐Diarylpyridine Ligands

“…After metalation of the phenyl ring, the released proton causes demetalation of one of the tolyl rings of the dtpy ligand. Similar transcycloplatination processes have been observed upon treatment of complexes of the type [Pt(C^N^C)(PR 3 )] (C^N^C=dicyclometalated 2,6‐di( p ‐fluorophenyl)pyridine; R= o ‐tolyl, propyl, butyl) with PhICl 2 , leading to the replacement of a metalated p ‐fluorophenyl ring by a metalated o ‐tolyl, propyl, or butyl moiety …”

“…After metalation of the phenyl ring, the releasedp roton causes demetalation of one of the tolyl rings of the dtpy ligand.Similar transcycloplatination processes have been observed upon treatment of complexes of the type [Pt(C^N^C)(PR 3 )] (C^N^C = dicyclometalated 2,6-di(p-fluorophenyl)pyridine; R= o-tolyl, propyl, butyl) with PhICl 2 ,l eadingt ot he replacement of am etalated p-fluorophenylr ing by am etalated o-tolyl, propyl, or butyl moiety. [64][65][66] Clear evidence for cyclometalationo ft he trz ligand in 6 is providedb yi ts 1 HNMR spectrum, which shows the resonance of the proton ortho to the metalated phenylc arbon atom as a doublet of doublets at d = 5.99 ppm with 195 Pt satellites (J(H,Pt) = 42 Hz). The signal of the proton ortho to the metalated carbon atom of the dtpyH ligand is observed at d = 6.27 ppm as as inglet with 195 Pt satellites (J(H,Pt) = 46 Hz).…”

Visible light driven generation and alkyne insertion reactions of stable bis-cyclometalated Pt(iv) hydrides

“…Irradiation of a solution of cis-N,N-[PtCl(dtpyH)(tpyH)] (cis-N,N-2ea) in acetone, generated in situ from the dimer 1e and excess tpyH, produced complex 3aa in 79% isolated yield aer 24 h, resulting from the cyclometalation of two tpyH ligands with loss of dtpyH 2 (Scheme 3). Therefore, this reaction involves a transcyclometalation [32][33][34][35][36] process, leading to the substitution of the dtpyH ligand by tpy. In contrast, the irradiation of an acetone solution of cis-N,N-[PtCl(dtpyH)(dfppyH)] (cis-N,N-2ec) led to the precipitation of the Pt(II) complex [PtCl(dtpyH 2 -kC)(dfppy)] (5ec, 63% yield; Scheme 3).…”