Synthesis and photophysical properties of aryl-substituted 2-borylbenzaldimines and their extended π-conjugated congeners.
Novel N-aryl-substituted 2-borylbenzaldimines 6 and related systems with extended π-framework 7 based on two borylbenzaldimine units linked by a spacer moiety were synthesized by condensation reactions of 2-(dimesitylboryl)benzaldehyde 3 with various amines 4 and diamines 5. All compounds were completely characterized including X-ray diffraction, especially in view of Lewis acid-base B-O and B-N interactions. The electronic as well as the photophysical properties of bisimines 7 were determined using cyclic voltammetry, UV/vis, and fluorescence spectroscopy and quantum chemistry. These compounds feature large Stokes shifts and reversible reduction waves. Interestingly, UV irradiation experiments unfold enhanced photostability for compounds 7 with an extended π-skeleton. By use of 1,8-diaminonaphthalene we observed the formation of a hitherto unknown BN-heterocyclic compound 9 fused with a perimidine skeleton. Structural and energetic aspects were evaluated by high level quantum chemical methods (DFT and SCS-MP2-calculations).
Westfälische Wilhelms-Universität, Corrensstraße 40, 48149 Münster, Germany.
Benedikt
B
Neue
Roland
R
Fröhlich
Birgit
B
Wibbeling
Aiko
A
Fukazawa
Atsushi
A
Wakamiya
Shigehiro
S
Yamaguchi
Ernst-Ulrich
EU
Würthwein
D018360:Crystallography, X-Ray; D007097:Imines / Q000138:chemical synthesis* / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D055668:Photochemical Processes; D011789:Quantum Theory; D013237:Stereoisomerism
D007097:Imines