Synthesis of reactive 1,3-diphenyl-6-aryl-substituted fulvene chromophores

This data article describes a detailed synthetic strategy and experimental data for the synthesis of brominated fulvene chromophores as reactive precursors/monomers for conjugated organic materials. Metal-mediated coupling reactions of brominated fulvenes would result in conjugated small molecules or polymers that would find application as organic light emitting diodes (OLEDs) and photovoltaic (PV) applications.


a b s t r a c t
This data article describes a detailed synthetic strategy and experimental data for the synthesis of brominated fulvene chromophores as reactive precursors/monomers for conjugated organic materials. Metal-mediated coupling reactions of brominated fulvenes would result in conjugated small molecules or polymers that would find application as organic light emitting diodes (OLEDs) and photovoltaic (PV) applications.
& 2018 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Value of the data
The data points to the synthesis of the aforementioned compounds.
The brominated fulvenes could be used as intermediates for synthesizing conjugated small molecules or polymers using metal-mediated reactions.
The conjugated small molecules and polyfulvenes could be used for organic light emitting diodes (OLEDs) and photovoltaic (PV) applications.

Data
All 1 H and 13 C NMR spectra were obtained using an Agilent Technologies 400 MHz instrument, and chemical shifts were reported in parts per million (δ) internally referenced to CDCl 3 ( 1 H NMR: δ¼7.26 ppm and 13 C NMR: δ¼77.0 ppm). Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectra were collected using a Thermo Nicolet FTIR spectrometer iS10. Mass spectrometry results were obtained using an Agilent Technologies G1969 ESI-LC/MS-TOF instrument consisting of a gradient LC system coupled to a time-of-flight mass spectrometer and electrospray ionization source or an Agilent Technologies 7890A GC system interfaced with a 5975C EI mass spectrometer.

Materials
Solvents, starting materials, and reagents were purchased either from Sigma-Aldrich, TCI America, or Alfa Aesar as reagent grade or higher quality and used as received unless otherwise noted. HPLC grade THF was dried and deoxygenated by passage through Innovative Technologies Pure-Solv solvent purification system equipped with Cu/Al columns. Premium grade silica gel used for column chromatography was purchased from Sorbent Technologies (60 Å, 40 À 63 nm (230 Â 400 Mesh)). All reactions and solvent transfers were carried out under an atmosphere of argon unless otherwise noted. All glassware was oven-dried prior to use.

Synthesis of (3)
A prepared solution of phenylmagnesium bromide in THF (2 M, 19 mL, 38 mmol) under N 2 was added dropwise over 30 min to a vigorously stirred solution of 2 (6.0 g, 25 mmol) in THF (200 mL) under N 2 . The resulting brown reaction mixture was allowed to stir at room temperature for 24 h under N 2 and followed by GC-MS to ensure complete conversion. The reaction mixture was cooled in an ice bath with vigorous stirring and quenched with the slow addition of cold water (100 mL). Dropwise addition of H 2 SO 4 (20 mL, 6 M) with vigorous stirring resulted in a brown organic layer and a clear aqueous layer. THF was evaporated under vacuum and the product was extracted with Et 2 O. The brown Et 2 O layer was separated from the acidic aqueous layer and washed sequentially with saturated NaHCO 3 (3 Â 200 mL), water (2 Â 200 mL), and saturated brine (1 Â 200 mL). The organic layer was dried over anhydrous MgSO 4 , filtered, and concentrated under vacuum to afford a brown solid and was triturated from acetone. Vacuum filtration, washing with cold acetone, and drying under reduced pressure afforded the product as a tan solid (3.96 g, 53%). 1

Synthesis of (4)
A freshly prepared solution of 4-bromophenylmagnesium bromide in Et 2 O (40 mL, 12.7 mmol) at 0°C was added dropwise over 30 min to a vigorously stirred solution of 2 (2.0 g, 8.4 mmol) in Et 2 O (200 mL) under N 2 . The resulting brown reaction mixture was allowed to stir at room temperature for 24 h under N 2 followed by GC-MS to ensure complete conversion. Additional reflux up to 24 h and addition of freshly prepared Grignard reagent was often necessary to achieve conversion. The reaction mixture was cooled in an ice bath and quenched with the slow addition of cold water (100 mL). Dropwise addition of H 2 SO 4 (10 mL, 6 M) with vigorous stirring resulted in a brown Et 2 O layer and a clear water layer, which was stirred for an additional 5 min. The brown Et 2 O layer was separated from the acidic aqueous layer and washed sequentially with saturated NaHCO 3 (3 Â 200 mL), water (2 Â 200 mL), and saturated brine (1 Â 200 mL). The organic layer was dried over anhydrous MgSO 4 , filtered, and concentrated under vacuum to afford a brown solid and triturated in hexane/ethyl acetate (70:30). Vacuum filtration, washing with cold hexane, and drying under reduced pressure afforded the product as a tan solid (1.67 g, 53%). 1 H NMR (400 MHz, CDCl 3 ): δ 3.72 (s, 2H), 6.94 (s, 2H), 7.38-7.50 (m, 8H); 13 C NMR (100 MHz, CDCl 3 ): δ 34. 91, 115.71, 121.45, 123.43, 127.63, 131.91, 137.25, 144