Tunable Multicolor Phosphorescence of Crystalline Polymeric Complex Salts with Metallophilic Backbones

Abstract

A total of 35 [Au(NHC) ][MX ] (NHC=N-heterocyclic carbene; M=Au or Cu; X=halide, cyanide or arylacetylide) complex salts were synthesized by co-precipitation of [Au(NHC) ] cations and [MX ] anions. These salts contain crystallographically determined polymeric Au⋅⋅⋅Au or Au⋅⋅⋅Cu interactions and are highly phosphorescent with quantum yields up to unity and emission color tunable in the entire visible regions. The nature of the emissive excited states is generally assigned to ligand (anion)-to-ligand (cation) charge-transfer transitions assisted by d ⋅⋅⋅d metallophilicity. The emission properties can be further tuned by controlled triple-component co-crystallization or by epitaxial growth. Correct recipes for white light-emitting phosphors with quantum yields higher than 70 % have been achieved by screening the combinatorial pool.

Tunable Multicolor Phosphorescence of Crystalline Polymeric Complex Salts with Metallophilic Backbones

“…[17] As ar epresentative example,t he crystal packing diagram of C3-A8 (in C2/m space group) is shown in Figure 1b to confirm the one-dimensional packing with alternating cations and anions connected by infinite d 10 ···d 10 metallophilic interactions in the solid state.T he intermetal Au···Audistances in C3-A8 is uniform to be 3.174 and the Au-Au-Aua ngle is 1808 8.T he Au···Aua nd Au···Cu distances found in the solved single crystal structures of the ten double salts are 3.182-3.384 and 3.373-3.398 ,respectively,which are comparable with those d 10 ···d 10 metallophilic interactions reported in the literature. [17] As ar epresentative example,t he crystal packing diagram of C3-A8 (in C2/m space group) is shown in Figure 1b to confirm the one-dimensional packing with alternating cations and anions connected by infinite d 10 ···d 10 metallophilic interactions in the solid state.T he intermetal Au···Audistances in C3-A8 is uniform to be 3.174 and the Au-Au-Aua ngle is 1808 8.T he Au···Aua nd Au···Cu distances found in the solved single crystal structures of the ten double salts are 3.182-3.384 and 3.373-3.398 ,respectively,which are comparable with those d 10 ···d 10 metallophilic interactions reported in the literature.…”

“…Te nsingle-crystal structures of the double salts have been solved with X-ray crystallography (Table S1 in the Supporting Information). [17] As ar epresentative example,t he crystal packing diagram of C3-A8 (in C2/m space group) is shown in Figure 1b to confirm the one-dimensional packing with alternating cations and anions connected by infinite d 10 ···d 10 metallophilic interactions in the solid state.T he intermetal Au···Audistances in C3-A8 is uniform to be 3.174 and the Au-Au-Aua ngle is 1808 8.T he Au···Aua nd Au···Cu distances found in the solved single crystal structures of the ten double salts are 3.182-3.384 and 3.373-3.398 ,respectively,which are comparable with those d 10 ···d 10 metallophilic interactions reported in the literature. [18] Thep hase homogeneity of the bulky solid samples has been confirmed by comparing the patterns recorded with powder X-ray diffraction (PXRD) and those simulated with the single crystal data (Figure S1-S5 and S6-S14).…”

“…In general, the emission maxima span from 448 nm for C1-A1 to 785 nm for C3-A14,emission lifetimes span from 0.1 msfor C3-A13 to 7.1 msf or C1-A2,a nd emission quantum yields span from 10 %f or C3-A10 to 99 %for C1-A5 and C2-A5. [17] Thed icyanoaurate and diiodoaurate anions have been determined to be 50 %occupancy each in the crystal lattice (Figure 4c). Solid samples of double salts C2-A1 and C2-A4 phosphoresce at peak maximum of 469 and 570 nm, respectively,and these two salts are essentially isostructural in both crystal lattice and molecular packing, [19] as determined with single crystal X-ray crystallography (Figure 4a,b).…”

“…We thus co-crystalized C2, A1 and A4 with the molar ratio of C2:A1:A4 of 2:1:1a nd successfully obtained as ingle crystal of the triple salts of C2-A1/A4 (A1:A4 = 1:1) suitable for Xray structure measurements. [17] Thed icyanoaurate and diiodoaurate anions have been determined to be 50 %occupancy each in the crystal lattice (Figure 4c). Thei ncorporation of the diiodoaurate (A4)anion into C2-A1 double salt does not alter the crystalline phase.A ctually, C2-A1, C2-A4,a nd C2-A1/A4 crystallize into P2 1 /c space group and the one-dimensional infinite metallophilic backbones run along c-axis with au niform intermetal distance of 3.283, 3.384, and 3.337 , respectively.W eh ave been able to record the emission spectrum of each of the single crystals with af luorimeter coupled to amicroscope.The C2-A1/A4 (A1:A4 = 1:1) single crystal show dual emission bands at 586/652 nm.…”

Controlling Metallophilic Interactions in Chiral Gold(I) Double Salts towards Excitation Wavelength‐Tunable Circularly Polarized Luminescence

“…Nanosecond timeresolved emission spectra (Supporting Information,Figure S2) show am uch faster decay (on the order of sub-ns timescale) for the high energy emission shoulder, revealing its nature as fluorescence.T he slow decay for the low energy emission peak with at ime constant of msi sa ssigned as phosphorescence. [14] Thee xcitation spectra for the two emission bands (Supporting Information, Figure S3) show an identical profile with the maximum located at about 365 nm. Consistently,u pon changing the excitation wavelength from 320 to 400 nm, the emission energies of both phosphorescence and fluorescence components remain unchanged ( Figure 2b;S upporting Information, Figure S3).…”