Chlorosuccinimide → 5-Chloro-3-dodecyl-2-(trimethylsilyl)ethynylthiophene

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Reaction Steps

First, 2-bromo-5-chloro-3-dodecylthiophene can be prepared by brominating 3-dodecylthiophene with 1 molar equivalent of N-bromosuccinimide (NBS) in N,N-dimethylformamide (DMF) at room temperature (rt) (as used herein, “room temperature” refers, for example, to a temperature ranging from about 22° C. to about 25° C.). Next, the chlorination of 2-bromo-3-dodecylthiophene with 1 molar equivalent of N-chlorosuccinimide (NCS) at room temperature generates 2-bromo-5-chloro-3-dodecylthiophene. Subsequently, 2-bromo-5-chloro-3-dodecylthiophene is reacted with a trimethylsilylacetylene in the presence of dichlorobis(triphenylphosphine) palladium (II) (Pd(PPh3)2Cl2) and copper(I) iodide (CuI) in triethylamine (Et3N) at elevated temperatures, such as 50° C. for a suitable time like 24 hours, and 80° C. for 3 hours under argon to form 5-chloro-3-dodecyl-2-(trimethylsilyl)ethynylthiophene. 5-Chloro-3-dodecyl-2-(trimethylsilyl)ethynylthiophene is stirred in a mixture of methanol/dichloromethane (1/2, v/v) in the presence of 10 percent mol of potassium carbonate at room temperature for a suitable time like 16 hours to produce 5-chloro-3-dodecyl-2-ethynylthiophene. 5-Chloro-3-dodecyl-2-ethynylthiophene is then reacted with isopropylmagnesium chloride, and then with anthraquinone or 6,13-pentacenequinone at 50° C. in tetrahydrofuran (THF) under argon, followed by reduction with tin (II) chloride (SnCl2) solution in 10 percent HCl at elevated temperatures like 50° C. The resultant 9,10-bis(5-chloro-3-dodecylthienylethynyl)anthracene (M1) or 6,13-bis(5-chloro-3-dodecylthienylethynyl) pentacene (M2) is polymerized using zinc in the presence of nickel (II) chloride (NiCl2), 2,2′-dipyridil, triphenylphosphine (PPh3) in N,N-dimethylacetamide (DMAc) at elevated temperatures like 80° C. for a suitable time like 48 hours. Poly(9,10-bis(3-dodecylthienylethynyl)anthracene (6a) and poly(6,13-bis(3-dodecylthienylethynyl) pentacene (22a) are thus obtained.

Provenance & Evidence