An Unprecedented Family of Luminescent Iridium(III) Complexes Bearing a Six-Membered Chelated Tridentate C^N^C Ligand

Abstract

A new family consisting of three luminescent neutral Ir(III) complexes with the unprecedented [Ir(C^N^C)(N^N)Cl] architecture, where C^N^C is a bis(six-membered) chelating tridentate tripod ligand derived from 2-benzhydrylpyridine (bnpy) and N^N is 4,4′-di-tert-butyl-2,2′-bipyridine (dtBubpy), is reported. X-ray crystallography reveals an unexpected and unusual double C–H bond activation of the two distal nonconjugated phenyl rings of the bnpy coupled with a very short Ir–Cl bond trans to the pyridine of the bnpy ligand. Depending on the substitution on the bnpy ligand, phosphorescence, ranging from yellow to red, is observed in dichloromethane solution. A combined study using density functional theory (DFT) and time-dependent DFT (TD-DFT) corroborates the mixed charge-transfer nature of the related excited states.

Exploration of the Structural and Photophysical Characteristics of Mono- and Binuclear Ir(III) Cyclometalated Complexes for Optoelectronic Applications

“…The recent investigation and design of new tridentate luminophores for OLEDs by Hierlinger et al [82] show the luminescent neutral tripod ligand made from 2-benzhydrylpyridine (bnpy) to form Ir(III) complex with the general formula [Ir(C^N^C)(N^N)X], where X represents a halogen and C^N^C represents tridentate tripod ligand. Modifications of the ancillary diimine ligand through electronic substitution enhance the photophysical and stability of the complexes, which thus act as an avenue to the designing of new tridentate phosphorescent compounds.…”

Directed ortho C–H borylation catalyzed using Cp*Rh(iii)–NHC complexes

“…31 P NMR (162 MHz, CDCl 3 ) δ -144. 4 (h, J = 712.6 Hz). 19 F NMR (376 MHz, CDCl 3 ) δ -71.9 (d, J = 713.0 Hz).…”

“…For minor diastereomer; 13 C NMR (101 MHz, CDCl3) δ 173. 4,169.0 (d,139.6,138.6,136.5,135.7,130.1,128.5,124.7,121.8,96.7 (d,62.2,21.8,21.2,19.8,18.8,9.2. HRMS (ESI)…”

“…Compound 4r was prepared according to the reported procedure 4 and obtained as off-white solid (0.820 g) Yield: 74%. 1 H NMR (400 MHz, CDCl3) δ 8.62 (ddd, J = 4.9, 1.9, 0.9 Hz, 1H), 7.60 (td, J = 7.7, 1.9 Hz, 1H), 4H),6H),7.14 (ddd,J = 7.5,4.8,1.2 Hz,1H), 7.11 (dt, J = 7.8, 1.1 Hz, 1H), 5.74 (s, 1H).…”

“…Yellow oil (64 % isolated yield, 77 % NMR yield as borylated product). 1 4.06 (q, J = 7.0 Hz, 2H), 1.42 (t, J = 7.0 Hz, 3H). 13 C NMR (101 MHz, CDCl3) δ 161.…”