Influence of X and R on the Emission of [Ru(X)(R)(CO)2(.alpha.-diimine)] (X = Halide, Mn(CO)5; R = alkyl): Change of Character of the Lowest-Excited State from MLCT (X = Cl) to XLCT (X = I) and .sigma.b.pi. (X = Mn(CO)5)

Influence of the variation of the co-ligands on the electronic transitions and emission properties of [Pt(I)(CH3)3(iPr-DAB)], [Pt(CH3)4(α-diimine)] and [Pt(SnPh3)2(CH3)2(iPr-DAB)]: an experimental and theoretical study

“…First of all, [Pt(I)(CH 3 ) 3 (iPr-DAB)] (1) emits in a glass at 90 K from its XLCT state with a lifetime of 6.9 µs, which is quite normal for charge transfer states at low temperatures. It is slightly longer than the XLCT emission lifetime of the related complex [Ru(I)(CH 3 )(CO) 2 (iPr-DAB)] (1.8 µs), 53 due to its higher emission energy.…”

A time-resolved infrared spectroscopic study of [M(SnR3)2(CO)2(α-diimine)] (M = Ru, Os; R = Ph, Me): evidence of charge redistribution in the lowest-excited state

“…13 If Cl Ϫ in [Re(Cl)(CO) 3 (bpy)] is replaced by I Ϫ the excited state obtains a halide(X)-to-ligand charge-transfer (XLCT) character 14 and the same holds for the complexes [Ru(X)(Me)(CO) 2 (α-diimine)] (α-diimine = bpy; RЈ-DAB: N,NЈ-di-RЈ-1,4-diaza-1,3-butadiene). [15][16][17] The nanosecond time-resolved IR (TRIR) spectrum of [Ru(Cl)(Me)-(CO) 2 (iPr-DAB)] exhibits a shift of the two ν(CO) vibrations on going from the ground state to the relaxed excited state of ca. ϩ50 cm Ϫ1 , which is consistent with the MLCT character of this state.…”

“…However, because of the dissociation barrier in the SBLCT state this photoreaction does not occur anymore at low temperature and under these circumstances the complexes have very long emission lifetimes compared to related compounds having a lowest MLCT state. For instance, [Ru(Cl)(Me)(CO) 2 (iPr-DAB)] emits at 650 nm in a 2-MeTHF glass at 90 K from its MLCT state with a lifetime of 0.3 µs, 16 whereas [Ru(SnPh 3 ) 2 (CO) 2 (iPr-DAB)] emits from its SBLCT state at 633 nm with a lifetime of 260 µs. 19 The increase in lifetime is due to the fact that the latter complex is much less distorted in its SBLCT state with respect to the ground state than [Ru(Cl)(Me)(CO) 2 (iPr-DAB)] in its MLCT state.…”

Probing the excited state nature of coordination complexes with blended organic and inorganic chromophores using vibrational spectroscopy

“…An example of this is the nature of X in the M-X system (M = metal, X = halide), which can influence the type of transition that is observed. [117][118][119][120] Although the direction of electron density change is similar, it has been found that when X is larger, the excited state character that predominates is XLCT rather than MLCT, which can be attributed to increased halide character in the HOMO of the complexes. Some of the first studies to investigate this were done on …”