690958-56-6

Upstream product

• 57114-80-4 1-(naphthalen-2-yl)-3-phenyl-propan-1,3-dione 
• 109-63-7 boron trifluoride diethyl etherate 
• 2459-25-8 methyl naphthalene-2-carboxylate 
• 98-86-2 acetophenone 
• 93-58-3 benzoic acid methyl ester 
• 93-08-3 methyl 2-naphthyl ketone 

Relevant academic research and scientific papers

Phosphorescence Tuning through Heavy Atom Placement in Unsymmetrical Difluoroboron β-Diketonate Materials

Difluoroboron β-diketonates (BF2bdks) show both fluorescence (F) and room-temperature phosphorescence (RTP) when confined to a rigid matrix, such as poly(lactic acid). These materials have been utilized as optical oxygen sensors (e.g., in tumors, wounds, and cells). Spectral features include charge transfer (CT) from the major aromatic donor to the dioxaborine acceptor. A series of naphthyl–phenyl dyes (BF2nbm) (1–6) were prepared to test heavy-atom placement effects. The BF2nbm dye (1) was substituted with Br on naphthyl (2), phenyl (3), or both rings (4) to tailor the fluorescence/phosphorescence ratio and RTP lifetime—important features for designing O2 sensing dyes by means of the heavy atom effect. Computational studies identify the naphthyl ring as the major donor. Thus, Br substitution on the naphthyl ring produced greater effects on the optical properties, such as increased RTP intensity and decreased RTP lifetime compared to phenyl substitution. However, for electron-donating piperidyl-phenyl dyes (5), the phenyl aromatic is the major donor. As a result, Br substitution on the naphthyl ring (6) did not alter the optical properties significantly. Experimental data and computational modeling show the importance of Br position. The S1 and T1 states are described by two singly occupied MOs (SOMOs). When both of these SOMOs have substantial amplitude on the heavy atom, passage from S1 to T1 and emission from T1 to S0 are both favored. This shortens the excited-state lifetimes and enhances phosphorescence.

Preparation and photophysical properties of fluorescent difluoroboronated β-diketones having phenanthrene moieties studied by emission and transient absorption measurements

Six difluoroboronated β-diketones having the phenanthrene skeleton (Phe@Ar) are prepared. Based on the measurements of the fluorescence quantum yields, lifetimes and transient absorption, the photophysical features of Phe@Ar are studied in comparison with those of difluoroboronated diketones having phenyl, naphthyl and anthryl moieties. β-Diketones having 1-, 2-, 3- and 9-phenanthryl moieties (PheDKAr) were prepared as the precursor to Phe@Ar. 1-Acetylphenanthrene was synthesized by the photocyclization method as the key building block of PheDKAr having the 1-phenanthryl moiety. The counter aromatic moieties (Ar) of the prepared PheDKAr are varied with phenyl, furyl and thienyl rings (Ar = Ph, F and T, respectively) to investigate the effects of π-conjugation on the fluorescence properties. The prepared Phe@Ars are fluorescent with appreciable fluorescence quantum yields which depend on the substitution position of the phenanthrene moiety. 3-Phe@Ph having the 3-phenanthryl moiety provides the largest fluorescence quantum yield (0.81) in acetonitrile among the Phe@Ars whereas 2-Phe@Ph having the 2-phenanthryl moiety shows the smallest fluorescence quantum yield (0.07) in acetonitrile. All the Phe@Ars show fluorescence also in the solid state, and the fluorescence spectra and quantum yields were determined. Transient absorption measurement using laser flash photolysis of the Phe@Ars revealed the triplet formation. DFT and TD-DFT calculations of Phe@Ars rationalize the dependency of the fluorescence quantum yields on the substitution position of the phenanthrene skeleton in terms of difference in the oscillator strength for the HOMO-LUMO transition.