The acid-mediated isomerization of iridium(iii) complexes with cyclometalated NHC ligands: kinetic vs. thermodynamic control

Abstract

The fac isomers of iridium(iii) complexes with metalated N-heterocyclic carbene (NHC) ligands are transformed cleanly into the mer isomers when solutions of the complexes are treated with first HNTf2 and then NEt3.

Selective syntheses of homoleptic Ir(iii) complexes bearing di-CF3-functionalized benzoimidazol-2-ylidenes for generation of blue phosphorescence

“…Furthermore, the reversible C–H activation and cyclometalation of aryl appendages is also responsible for the selective formation of a single product in the presence of sodium acetate at elevated temperature. 45,46…”

“…Furthermore, the reversible C-H activation and cyclometalation of aryl appendages is also responsible for the selective formation of a single product in the presence of sodium acetate at elevated temperature. 45,46 A single crystal X-ray diffraction study on m-Ir(dfp) 3 and f-Ir (tBpp) 3 was executed to confirm the coordination arrangement of chelates. Particularly, the unique Ir-C1 vector, that is uniquely located trans to the Ir-C (carbene) vector, is the shortest among all Ir-C (aryl) vectors, showing the reduced trans-effect of carbene in reference to the aryl entities.…”

Blue Electrophosphorescence from Iridium(III) Phosphors Bearing Asymmetric Di‐N‐aryl 6‐(trifluoromethyl)‐2H‐imidazo[4,5‐b]pyridin‐2‐ylidene Chelates

“…Moreover, no m ‐isomer was detected within this system, despite that acid treatment was known to give the reversed fac ‐to‐ mer transformation under controlled condition. [ 21 ]…”

“…Moreover, no m-isomer was detected within this system, despite that acid treatment was known to give the reversed fac-to-mer transformation under controlled condition. [21] All Ir(III) complexes showed an essentially identical M + ion in their mass spectra. The 1 H and 19 F NMR analyses suggested that f-ct6a possesses the highly symmetrical arrangement of chelates, i.e., possible existence of C3 symmetry.…”

Peripheral engineering of Ir(iii) emitters with imidazo[4,5-b]pyrazin-2-ylidene cyclometalates for blue organic light emitting diodes

“…29 A recent report on homoleptic Ir( iii ) complexes bearing metalated N-heterocyclic carbenes may also provide clues to the possible intermediates and pathway of isomerization processes. 30…”