The effect of gold(i) coordination on the dual fluorescence of 4-(dimethylamino)pyridine

Abstract

The reactions of 4(dimethylamino)pyridine (DMAP) with the gold(I) precursors [AuR(tht)] (R = C6F5, C6Cl2F3 or C6Cl5; tht = tetrahydrothiophene) lead to complexes [AuR(DMAP)] (R = C6F5 (1), C6Cl2F3 (2) or C6Cl5 (3)). X-ray diffraction studies of the complexes reveal the presence of discrete molecules in which aurophilic contacts are absent, with π-stacking (1) or hydrogen bond (2) interactions being responsible for the supramolecular arrangements found in the solid state. All complexes display fluorescence in solution in solvents of different polarities such as toluene, chloroform or acetonitrile. In all cases the emission energy is similar to the low-energy Twisted Intramolecular Charge Transfer (TICT) emission of free DMAP. TDDFT calculations confirm that the fluorescence of complexes 1-3 arises from the ICT excited state of bonded DMAP in which a 90° distortion of the pyridine ring and -NMe2 planes is observed. Model calculations based on experimental parameters show a higher degree of polarization of DMAP upon coordination to Au(I) organometallic fragments.

(C7H11N2)2MBr4 (M=Cu, Zn): X‐Ray Sensitive 0D Hybrid Metal Halides with Tunable Broadband Emission

“…Coinciding with this absence comes the increase of excitation from 362 nm, which overlaps with a small shoulder in the excitation of (DMAP)Br, as marked with an arrow (Figure 4). Photoemission properties of 4‐dimethylaminopyridine and similar compounds have been reported previously [34–37] . Based on the reported literature, the emission from the organic cations is due to intramolecular charge transfer (ICT), with proposed mechanisms including twisted intramolecular charge transfer (TICT), rehybridization intramolecular charge transfer (RICT), wagging intramolecular charge transfer (WICT), or planar intramolecular charge transfer [35,38–40] .…”

“…Photoemission properties of 4-dimethylaminopyridine and similar compounds have been reported previously. [34][35][36][37] Based on the reported literature, the emission from the organic cations is due to intramolecular charge transfer (ICT), with proposed mechanisms including twisted intramolecular charge transfer (TICT), rehybridization intramolecular charge transfer (RICT), wagging intramolecular charge transfer (WICT), or planar intramolecular charge transfer. [35,[38][39][40] López-de-Luzuriaga et al, reports in their DMAPÀ Au complex that the lower energy emission around 443 nm is due to charge transfer from the phenyl ring to the dimethylamino group.…”

“…[34][35][36][37] Based on the reported literature, the emission from the organic cations is due to intramolecular charge transfer (ICT), with proposed mechanisms including twisted intramolecular charge transfer (TICT), rehybridization intramolecular charge transfer (RICT), wagging intramolecular charge transfer (WICT), or planar intramolecular charge transfer. [35,[38][39][40] López-de-Luzuriaga et al, reports in their DMAPÀ Au complex that the lower energy emission around 443 nm is due to charge transfer from the phenyl ring to the dimethylamino group. They also report that the high energy transition seen in noncomplexed DMAP, corresponding to the 361 nm emission in (DMAP)Br, is due a π-π* transition in the pyridine ring.…”

Dipole Moment‐ and Molecular Orbital‐Engineered Phosphine Oxide‐Free Host Materials for Efficient and Stable Blue Thermally Activated Delayed Fluorescence

“…In addition, the polarity of the solvents changes the emission state of TICT molecules between a locally excited state and CT state by changing the twist angle between the electron accepting moiety and electron donating one, because they are not used again in the paper except their combination, donor‐acceptor (D‐A). [ 25 ] When fabricated with H1–H4 and DPEPO, 1PCTrz also exhibited redshifted (8–14 nm) and broadened (7–9 nm) PL emission compared to that with mCBP and mCBP‐CN, as shown in Figure 2d . The PL peak wavelengths and full‐width at half maximum (FWHM) values for all the tested host:1PCTrz films are summarized in Table 1 .…”

Polarity- and molecular orbital-engineered host materials for stable and efficient blue thermally activated delayed fluorescence

“…In addition, the polarity of the solvents changes the emission state of TICT molecules between a locally excited (LE) state and CT state by changing the twist angle between the electron accepting moiety (A) and electron donating one (D). 20 When fabricated with H1-H4 and DPEPO, 1PCTrz exhibited redshifted and broadened PL emission compared to that with mCBP and mCBP-CN, as shown in Figure 2d. The PL peak wavelengths and full-width at half maximum (FWHM) values for all the tested host:1PCTrz (host:1PCTrz) lms are summarized in Table 1.…”