Synthesis and photophysical properties of Ir(iii)/Re(i) dyads: control of Ir→Re photoinduced energy transfer

Linking ReI and PtII Chromophores with Aminopyridines: A Simple Route to Achieve a Complicated Photophysical Behavior

“…The experimental kinetic data (luminescence decay monitoring at 490 and 650 nm) obtainedf or the dilutes olution was simulatedb yu sing this model and gave av ery good fit (Figure 11 A) with the following kinetic parameters: t 1 = 2.3 ms, t 2 = 1.1 ms, k ET = k' ET = 0.05 ms À1 .T he estimated rates of PET are around1 0 3 lower than those reported for some Ir-Re dyads, [15] which is in line with the insulating nature of the aminopyridine bridgea nd ar ather large spatial Pt···Res eparation, which exceeds 10 for 7.T he PET process has ar ather minor influence on the observed photophysical behavior,b ecause it is at least 8.7 times slower than the rates of radiativer elaxation of {Pt} (k r = 1/t 2 = 0.43 ms À1 )a nd {Re} (k r = 1/t 2 = 0.91 ms À1 )c hromophores. The experimental kinetic data (luminescence decay monitoring at 490 and 650 nm) obtainedf or the dilutes olution was simulatedb yu sing this model and gave av ery good fit (Figure 11 A) with the following kinetic parameters: t 1 = 2.3 ms, t 2 = 1.1 ms, k ET = k' ET = 0.05 ms À1 .T he estimated rates of PET are around1 0 3 lower than those reported for some Ir-Re dyads, [15] which is in line with the insulating nature of the aminopyridine bridgea nd ar ather large spatial Pt···Res eparation, which exceeds 10 for 7.T he PET process has ar ather minor influence on the observed photophysical behavior,b ecause it is at least 8.7 times slower than the rates of radiativer elaxation of {Pt} (k r = 1/t 2 = 0.43 ms À1 )a nd {Re} (k r = 1/t 2 = 0.91 ms À1 )c hromophores.…”

“…The latter,t ogether with intra-and intermolecular energy-transfer processes, determines the appearance of multiple emission bands and results in nonlinear relaxation kinetics of the exciteds tates.[a] K.Supporting information and the ORCID identification number for the authorofthis article can be found under https://doi.emission originating from the constituting metal-based fragments remain scarce and are represented by severald -metallanthanide (d-f) [12] and al imited number of (d-d) dyads, the latter containing combinations of Re I -Ru II , [13] M 3 I -Re I -M 3 I (M = Cu I ,A g I ), [14] Re I -Ir III , [15] andI r III -Ru II[16] chromophores. Complexes 2 and 3 with NH 2 -coordinated L2 and L3,r espectively,w ere coupled with cycloplatinated motifs {Pt(ppy)Cl} and {Pt(dpyb)} + (ppy = 2phenylpyridine, dpyb = dipyridylbenzene) to give the bimetallic species [Re(phen)(CO) 3 (m-L2/L3)Pt(ppy)Cl] + (4, 6)a nd [Re(phen)(CO) 3 (m-L2/L3)Pt(dpyb)] 2 + (5, 7).…”

“…Supporting information and the ORCID identification number for the authorofthis article can be found under https://doi.emission originating from the constituting metal-based fragments remain scarce and are represented by severald -metallanthanide (d-f) [12] and al imited number of (d-d) dyads, the latter containing combinations of Re I -Ru II , [13] M 3 I -Re I -M 3 I (M = Cu I ,A g I ), [14] Re I -Ir III , [15] andI r III -Ru II[16] chromophores. However, these speciesd isplay intrinsically low quantum efficiencies, mostly due to the significant quenching of high-energyc omponents through partially operating photoinduced ET.…”

Ir(III) and Ir(III)/Re(I) complexes of a new bis(pyrazolyl-pyridine) bridging ligand containing a naphthalene-2,7-diyl spacer: Structural and photophysical properties

“…X-ray quality crystals of both products could be obtained from MeCN/ether and their structures are discussed here; coordination sphere bond distances are collected in Table 2. the usual 6-coordinate geometry with the two phenylpyridine chelates arranged such that the N atoms are mutually trans and the C atoms are mutually cis [2][3][4][5], with the bidentate pyrazolyl-pyridine chelate therefore occupying the two coordination sites trans to the C atoms. The most interesting feature of the structure is that the plane of the pendant naphthyl group is twisted with respect to that of the coordinated pyrazolyl-pyridine unit from which it is pendant, such that it can lie parallel to and overlapping with one of the F 2 ppy ligands [containing N(11C) and C(26C)]; atoms in the F 2 ppy ligand lie in the range 3.2 -3.4 Å from the mean plane of the naphthyl group, indicating that they are separated by an ideal -stacking distance [4].…”

“…Firstly, they have formed the basis of an extensive family of selfassembled coordination cages which display interesting structures and guest binding properties [1]. Secondly, they have been used as a basis for preparing luminescent heterodinuclear complexes in which a blue-luminescent {Ir(ppy) 2 (NN)} + unit [2] is connected to {Ln(hfac) 3 (NN)} [3,4] or {Re(CO) 3 Cl(NN)} [5] units in order to investigate phenomena such as inter-component photoinduced energy-transfer and white light emission. The ease with which the basic 3-(2-pyridyl)-1H-pyrazole unit can be functionalised by alkylation at the pyrazolyl N 1 site provides a facile synthetic route into a wide range of such ligands, and has allowed in particular the incorporation of napthyl units as aromatic spacers between the chelating termini [4,6,7].…”