Coupling d⁶ Ir(III) and d⁸ Pt(II) Chromophores

Abstract

Two classes of widely studied luminescent metal complexes are octahedral d (i.e., Ir) and square planar d (i.e., Pt) polypyridyl complexes, which have distinctly different photophysics and photoreactivity. In this study we report a series of d-d Ir-Pt hybrid complexes arising from coordination of metalloligands IrL(benzene-1-thioether-2-thiolate) or Ir(L)(benzene-1,2-dithiolate) anion [L = 2-phenylpyridine (ppy), 2-(2,4-difluorophenyl)pyridine (dfppy), or 1-phenylisoquinoline (piq)] to Pt(terpy) (terpy = 2,2':6',2″-terpyridine). X-ray crystal structures of the Ir-Pt complexes show the IrL and Pt(terpy) chromophores are cofacially oriented with interplanar distances of 3.268-3.442 Å. Density functional theory (DFT) calculations show that the highest occupied molecular orbital and the lowest unoccupied molecular orbital are localized in the IrL and the Pt(terpy), respectively. All the complexes display a low-energy absorption band (λ = 460-534 nm, ε = (0.75-2.13) × 10 M cm), which is attributed to interchromophore-charge-transfer (ICCT) transition, according to time-dependent DFT calculations. The ICCT excited state is emissive, giving long-lived phosphorescence that reaches as low as near-infrared (λ = 668-710 nm, τ = 0.17-0.79 μs).

Fast Synthesis of Iridium(III) Complexes Incorporating a Bis(diphenylphorothioyl)amide Ligand for Efficient Pure Green OLEDs

“…The Ir−S bond lengths range from 2.455(2) to 2.473(2) Å, significantly longer than the corresponding Ir−O bond in the similar reported Ir−tpip structures; the Ir−C bond lengths are in the range of 1.999(10) to 2.028(10) Å, whereas the bond lengths of Ir−N are between 2.042(8) and 2.071(9) Å. Meanwhile, the dihedral angles between S−Ir−S atoms are within the range from 99.92°(9) to 103.24° (8), and the torsion angles between P−S−N atoms are within the range from 117.8°(3) to 120.8° (4). The rest of C−C and C−N bond lengths are similar to that of other reported Ir(III) complexes.…”

“…A sulfur atom is electron-rich and capable of stabilizing metal ions in unusual oxidation states. 8 The lone pair on a sulfur atom can have additional two metal−sulfur (M− S) bonding interaction in coplanar structures. 9 The M−S units are commonly reported in Ag, Au, Zn, Fe, Cu, Pd, and Rh complexes, which lead to unique structural and photophysical properties.…”

“…The coordination pattern of iridium complexes has been thoroughly investigated throughout the years; however, iridium complexes in direct coordination with sulfur atoms are seldom reported and studied. A sulfur atom is electron-rich and capable of stabilizing metal ions in unusual oxidation states . The lone pair on a sulfur atom can have additional two metal–sulfur (M–S) bonding interaction in coplanar structures .…”

Facile Synthesis of Luminescent Ir–Pt–Ir Trimetallic Complexes

“…In addition, such constructs can serve as models for understanding the long‐range excited‐state and charge transport processes found in natural photosynthesis . As such, a large number of photoactive multimetallic complexes have been prepared and studied …”

“…[10][11][12][13][14] As such, al arge number of photoactive multimetallicc omplexes have been prepared and studied. [15][16][17][18][19][20][21][22] Among the large variety of availablephotoactive metalc omplexes, the supramolecular chemistry of d 6 Ru II polypyridyl complexes is the most advanced, with av ery mature synthetic chemistry that has allowed the assembly of many complex structuresf eaturing ruthenium polypyridyl units. [1][2][3][4]23] More recently,t he supramolecular photochemistry of d 8 Pt II has emerged,f acilitated by the ability to use coordination-driven self-assembly approachest op repare two-dimensional metallacycles or three-dimensional cages of many different shapes and sizes.…”