Preparation of metalated azine complexes of iridium(III)

Arylaldazine and acetoneazine complexes [IrCl(eta(5)-C5Me5){kappa(1)-[N=C(H)(R2C(6)H(4))]-N=C(H)(R2C(6)H(4))}{P(OR1)(3)}]-BPh4 (1, 2) and [IrCl(eta(5)-C5Me5){kappa(1)-[N=C(CH3)(2)]-N=C(CH3)(2)}{P(OR1)(3)}]BPh4 (3, 4) [R1 = Me (1, 3), Et (2, 4); R2 = H (a), 4-CH3 (b), 2,6-(CH3)(2) (f)] were prepared by allowing chloro complexes IrCl2(eta(5)-C5Me5)[P(OR1)(3)] to react first with AgOTf and then with the appropriate azine. In solution, kappa(1)-complexes 1-4 undergo a metalation reaction, affording chelate kappa(2)-azine derivatives [Ir{kappa(2)-R2C6H3(H) C=N-N=C(H)(R2C(6)H(4))}(eta(5)-C5Me5){P(OR1)(3)}] BPh4 (5, 6) and [Ir{kappa(2)-CH2(CH3)C=N-N=C(CH3)(2)}(eta(5)-C5Me5){P(OR1)(3)}]BPh4 (7, 8) [R1 = Me (5, 7), Et (6, 8); R2 = H (a), 4-CH3 (b), 4-CH3O (c); 4-F (d), 4-NO2 (e)]. The complexes were characterised spectroscopically and by X-ray crystal structure determination of [Ir{kappa(2)-C6H4(H)C=N-N=C(H)(C6H5)}(eta(5)-C5Me5){P(OEt)(3)}]BPh4 (6a). Most of the kappa(2)-arylazine derivatives showed photoluminescence properties upon excitation with near-UV and violet light, with emission peaks at around 650 nm. The photoluminescence features were rationalised according to DFT calculations.