2-Bromotetraazapentacene and Its Functionalization by Pd(0)-Chemistry

Abstract

We have synthesized a brominated N,N'-dihydrotetraazapentacene using a condensation route. Sonogashira reactions replace the Br-substituent by an alkynyl group, placed on the azaacene core. Sonogashira coupling of brominated dihydro tetraazapentacene 1H2 with alkynes and subsequent oxidation afford several functionalized TIPS-tetraazapentacene derivatives with energetically stabilized FMOs. These TIPS-TAPs are either crystalline or amorphous, depending upon their substitution pattern.

Stabilization by Benzannulation: Butterfly Azaacenes

“…Scheme shows the two different methods that access compounds 1 – 3 ; 1‐H 2 was obtained from a dibromo‐dihydro‐azaacene by a double Stille reaction (Scheme ). The dihydro species was used to prevent deactivation of the palladium catalyst by oxidation . Reoxidation with MnO 2 gave the purple, well‐soluble, arrow‐shaped tetraazahexacene 1 .…”

“…The dihydro species was used to preventd eactivation of the palladium catalystb yo xidation. [13] Reoxidation with MnO 2 gave the purple, well-soluble, arrow-shaped tetraazahexacene 1.C ondensationo fp henanthrenequinone with ortho-diamines gave red 2a and dark green 3a in reasonable to excellent yields. Because both compoundsa re only moderately soluble in common organic solvents, we deployed bis-(TIPSethynyl)-substitutedp henanthrenequinone (see the Supporting Information for synthesis) for benzannulation, increasing the solubility significantly (> 15 mg mL À1 in chloroform).…”

“…) 13. CNMR (151 MHz, CD 2 Cl 2 ) d = 146.1, 144.2, 143.9, 143.4, 135.8, 132.9, 131.4, 130.9, 130.4, 129.6, 128.8, 125.5, 124.2, 123.9, 123.1, 113.1, 104.2, 19.3, 12.3 ppm.…”

Anticipating Acene-Based Chromophore Spectra with Molecular Orbital Arguments

“…). The design principle correctly applies to acene dimers, oligomers and polymers such as A, 37 B, 33 F, 38 G 39 and H, 40 complex geometries such as C,34 I, 41,42 J 43 and K, 44 and to heteroatom-substituted dimers D,35 E,36 and L. 45 R denotes a solubilising or stabilising group. liquid crystals, 41 polymer synthesis, 42 sensors, 45 photovoltaic applications,37,39,43 and one to explore structure-spectrum relationships 32.…”

Palladium nanoparticles supported on fluorine-doped tin oxide as an efficient heterogeneous catalyst for Suzuki coupling and 4-nitrophenol reduction

“…Nano-sized palladium (Pd) is a crucial transition metal especially in its function as a catalyst in cross-coupling reactions such as Suzuki-Miyaura, Mizoroki-Heck, Sonogashira, Hiyama, Kumada and Stille reactions. [1][2][3][4][5][6] These cross-coupling reactions are utilized in many industrial applications due to the formation of arylaryl, C-C and C-X chemical bonds which are primary steps to synthesize essential intermediates. These remarkable reactions are synthesized products which are important intermediates for pharmaceutical industries, material science, natural products and polymers.…”