Nitrogen → 3,3'''-Dihexyl-2,2':5',2'':5'',2'''-quaterthiophene

Reaction equation

Br[C:2]1[S:6][C:5]([C:7]2[S:8][C:9](Br)=[CH:10][CH:11]=2)=[CH:4][CH:3]=1.N#N.[NH4+].[Cl-].C(O[CH2:20][CH3:21])C>>[CH2:20]([C:4]1[CH:3]=[CH:2][S:6][C:5]=1[C:7]1[S:8][C:9]([C:9]2[S:8][C:7]([C:5]3[S:6][CH:2]=[CH:3][C:4]=3[CH2:9][CH2:10][CH2:11][CH2:7][CH2:20][CH3:21])=[CH:11][CH:10]=2)=[CH:10][CH:11]=1)[CH2:21][CH2:2][CH2:3][CH2:4][CH3:5]

Participants

Reactant 4

HCID 947Nitrogen

HCID 3283Diethyl Ether

HCID 25517Ammonium Chloride

HCID 6389085,5'-Dibromo-2,2'-bithiophene

Product 1

HCID 121416303,3'''-Dihexyl-2,2':5',2'':5'',2'''-quaterthiophene

Conditions

Temperature: 20 °C

Procedure

The Grignard reagent prepared above, added dropwise to a suspension of 5.0 g (15.4 mmoles) of 5,5′-dibromo-2,2′-bithiophene and 0.084 g (0.154 mmoles) of Ni(dppp)2Cl2 in 50 mL dry ethyl ether. Typically, the Grignard is added from a feeding funnel under an inert gas (e.g., N2). The resulting mixture was heated to reflux for about 20 hours. The resulting mixture is cooled to about room temperature (e.g., to about 20° C.) and combined with about 200 mL of 5% aqueous NH4Cl to which some ice is added, to effect hydrolysis. The aqueous phase is extracted with about 2×100 mL of CH2Cl2. The organic phases combined are back washed with about 200 mL water and dried over MgSO4. The solvent is evaporated to give a raw product, 3,3′″-dihexyl-[2,2′;5′,2″;5″,2′″]quaterthiophene, which can be purified using, for example, a silica-gel column using hexanes 100% as eluant to give 6.4 g of material, (yield=83.4%). Proton NMR can be used to determine the presence of the raw product: 1HNMR: 7.25 ppm, (2H, d), 7.20 ppm, (2H, d), 7.10 ppm, (2H, d), 7.00 ppm, (2H, d), 2.83 ppm, (4H, t), 2.7 ppm, (4H, m), 1.41 ppm, (12H, m), 1.00 ppm, (6H, m).