32281-36-0

Basic information

• Product Name: Benzo[1,2-b:4,5-b']dithiophene-4,8-dione
• Synonyms: Benzo[1,2-b:4,5-b']dithiophene-4,8-dione;4,8-Dihydrobenzo[1,2-b:4,5-b']dithiophen-4,8-dione;8-Dihydrobenzo[1,2-b:4,5-b']dithiophen-4,8-dione;NSC 149690;benzo[1,2-b:4,5-b']bisthiophene-4,8-dione;4,8‐Dihydrobenzo[1,2‐ b:4,5‐b']dithiophen‐ 4,8‐dion;4,8-Dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione;Thieno[2,3-f]benzothiophene-4,8-dione
• CAS NO: 32281-36-0
• Molecular Formula: C₁₀H₄O₂S₂
• Molecular Weight: 220.268
• EINECS: 605-241-0
• Mol File: 32281-36-0.mol
• Article Data: 29

Chemical Properties

• Melting Point: 260-262℃
• Boiling Point: 408 °C at 760 mmHg
• Flash Point: 200.6 °C
• Appearance: /
• Density: 1.595
• Storage Temp.: Keep in dark place,Sealed in dry,Room Temperature
• CAS DataBase Reference: Benzo[1,2-b:4,5-b']dithiophene-4,8-dione(CAS DataBase Reference)
• NIST Chemistry Reference: Benzo[1,2-b:4,5-b']dithiophene-4,8-dione(32281-36-0)
• EPA Substance Registry System: Benzo[1,2-b:4,5-b']dithiophene-4,8-dione(32281-36-0)

Safety Data

• Safety Statements: 24/25
• WGK Germany: 3
• Hazardous Substances Data: 32281-36-0(Hazardous Substances Data)

Usage

Description

Benzo[1,2-b:4,5-b’]dithiophene is a planar symmetrical molecular structure of the thiophene derivative, enabling a better π-π?stacking and good electron delocalization that encourages charge transport. In recent years, it has been intensively studied for the application of OFETs and OPVs. The incorporation of a low-band-gap unit into the benzo[1,2-b:4,5-b’]dithiophene unit could potentially result in a red-shifted absorption due to its electron-rich properties. Benzo[1,2-b:4,5-b’]dithiophene can be chemically modified to fine-tune its chemical structure and electron properties (e.g. band gap), energy levels, and charge mobility of the small molecule/polymers of interest (at a molecular level).

Uses

Different sources of media describe the Uses of 32281-36-0 differently. You can refer to the following data:
1. BDTD can be used as an acceptor layer in the fabrication of polymer based solar cells.
2. suzuki reaction

General Description

Benzo[1,2-b:4,5-b′]dithiophene-4,8-dione (BDTD) is a conductive polymer with a symmetric and planar conjugated structure which has a hole mobility of 0.25 cm2V-1s-1.

Synthetic route

3-thiophenecarboxylic acid,N,N-diethylamide (73540-75-7) → 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0)

Conditions	Yield
With n-butyllithium In tetrahydrofuran at 0 - 20℃; Temperature; Inert atmosphere;	86.1%
With n-butyllithium In tetrahydrofuran at 20℃; for 1h; Inert atmosphere; Cooling with ice;	80%
With n-butyllithium In tetrahydrofuran at 0℃;	80%

3-thiophene carboxaldehyde (498-62-4) + 3-thiophenecarboxylic acid,N,N-diethylamide (73540-75-7) → 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0)

Conditions	Yield
With N,N,N,N,-tetramethylethylenediamine; sec.-butyllithium In diethyl ether 1.) -78 deg C, 1 h, 2.) -78 deg C -> RT, 12 h;	77%

3-thiophene carboxylic acid chloride (41507-35-1) + 3-thiophenecarboxylic acid,N,N-diethylamide (73540-75-7) → 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0)

Conditions	Yield
With n-butyllithium In tetrahydrofuran at -30 - 20℃; Inert atmosphere;	77%

N,N-dimethyl-3-thiophene carboxamide (59906-37-5) → 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0)

Conditions	Yield
With n-butyllithium In diethyl ether; hexane for 12h;	56%
With n-butyllithium In hexane; water; benzene

2,3-thiophenedicarboxylic acid anhydride (6007-83-6) → 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0)

Conditions	Yield
In neat (no solvent) at 270℃; for 2.5h;	24%

2,3-thiophenedicarboxylic acid anhydride (6007-83-6) → 4H-cyclopenta[2,1-b:3,4-b']dithiophen-4-one (25796-77-4) + 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0)

Conditions	Yield
at 500℃; under 1 - 5 Torr;	A 1.2% B n/a

1H,3H-thieno[3,4-c]furan-1,3-dione (6007-85-8) → 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) + 4,8-Dihydrobenzo<1,2-b:4,5-c'>dithiophen-4,8-dion (33527-22-9)

Conditions	Yield
at 470℃; for 0.00833333h;	A 0.12% B 0.36%

n-butyllithium (109-72-8, 29786-93-4) + 3-thiophenecarboxylic acid,N,N-diethylamide (73540-75-7) → 1-(3-thienyl)-1-pentanone (90534-16-0) + 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) + N,N-diethyl-2-(1,1,1,3,3-pentafluoro-2-hydroxypropan-2-yl)thiophene-3-carboxamide (148527-59-7)

Conditions	Yield
With N,N,N,N,-tetramethylethylenediamine; foscarnet 1.) hexane, ether, -78 deg C, 1.5 h, 2.) hexane, ether, a) -78 deg C, 7 h, b) RT, 12 h; Yield given. Multistep reaction. Yields of byproduct given;

1,1,1,3,3-pentafluoro-2-propanone (431-71-0) + 3-thiophenecarboxylic acid,N,N-diethylamide (73540-75-7) → 1-(3-thienyl)-1-pentanone (90534-16-0) + 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) + N,N-diethyl-2-(1,1,1,3,3-pentafluoro-2-hydroxypropan-2-yl)thiophene-3-carboxamide (148527-59-7)

Conditions	Yield
With n-butyllithium; N,N,N,N,-tetramethylethylenediamine 1.) hexane, ether, -78 deg C, 1.5 h, 2.) hexane, ether, a) -78 deg C, 7 h, b) RT, 12 h; Yield given. Multistep reaction. Yields of byproduct given;

3-thiophenecarboxylic acid,N,N-diethylamide (73540-75-7) → 1-(3-thienyl)-1-pentanone (90534-16-0) + 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) + N,N-diethyl-2-(1,1,1,3,3-pentafluoro-2-hydroxypropan-2-yl)thiophene-3-carboxamide (148527-59-7)

Conditions	Yield
With n-butyllithium; N,N,N,N,-tetramethylethylenediamine; foscarnet 1.) hexane, ether, -78 deg C, 1.5 h, 2.) hexane, ether, a) -78 deg C, 7 h, b) RT, 12 h; Yield given. Multistep reaction. Yields of byproduct given;

benzo[1,2-b:4,5-b']dithiophene (267-65-2) → 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0)

Conditions	Yield
With sodium dithionite; tetrabutylammomium bromide In water for 0.166667h; Inert atmosphere;

4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) + dimethyl 4,5-bis(methylthio)-1,3-dithiole phosphonate ester (138519-02-5) → 8-(4,5-bis(methylthio)-1,3-dithiol-2-ylidene)benzo[1,2-b:4,5-b']dithiophen-4(8H)-one

Conditions	Yield
Stage #1: dimethyl 4,5-bis(methylthio)-1,3-dithiole phosphonate ester With n-butyllithium In tetrahydrofuran at -78℃; for 1.5h; Stage #2: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione In tetrahydrofuran at -78 - 20℃;	99%

4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) + trimethyl orthoformate (149-73-5) → 4,4,8,8-tetramethoxy-4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene

Conditions	Yield
With triethylamine In methanol for 18.1667h; Inert atmosphere; Reflux;	99%

4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) + octylmagnesium bromide (17049-49-9) → 8-hydroxy-8-octylbenzo[1,2-b:4,5-b']dithiophen-4-one

Conditions	Yield
In toluene at 0 - 20℃;	98.7%
In toluene at 0 - 20℃; Inert atmosphere;	98.7%
In toluene

4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) + 2-bromo-5-(2-ethylhexyl)thiophene (925899-21-4) → 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4-hydroxy-4-(2-(2-ethylhexyl)thiophen)-8-one

Conditions	Yield
Stage #1: 2-bromo-5-(2-ethylhexyl)thiophene With magnesium In tetrahydrofuran for 5h; Reflux; Stage #2: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione In toluene at 20℃; for 1h;	97.6%
Stage #1: 2-bromo-5-(2-ethylhexyl)thiophene With iodine; magnesium In tetrahydrofuran for 3h; Inert atmosphere; Reflux; Stage #2: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione In toluene at 20℃; for 30h; Inert atmosphere;	65%

4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) → benzo[1,2-b:4,5-b']dithiophene-4,8-dione dioxime (1430594-30-1)

Conditions	Yield
With pyridine; hydroxylamine hydrochloride Reflux; Inert atmosphere;	97%

4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) → 2,6-dibromobenzo[1,2-b:4,5-b']dithiophene-4,8-phenylhydrazine (196491-93-7)

Conditions	Yield
With bromine at 20℃; for 1.5h; Reagent/catalyst; Temperature;	96%

4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) + dimethyl sulfate (77-78-1) → 4,8-Dimethoxybenzo<1,2-b:4,5-b'>dithiophene (85903-02-2)

Conditions	Yield
Stage #1: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione With sodium tetrahydroborate In ethanol; water for 0.666667h; Inert atmosphere; Schlenk technique; Stage #2: With potassium hydroxide In ethanol; water for 0.5h; Inert atmosphere; Schlenk technique; Reflux; Stage #3: dimethyl sulfate In ethanol; water for 8h; Inert atmosphere; Schlenk technique; Reflux;	96%
Stage #1: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione With sodium tetrahydroborate In ethanol; water for 1h; Stage #2: With potassium hydroxide In ethanol; water for 0.5h; Stage #3: dimethyl sulfate In ethanol; water for 64h;	5.3 g

4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) + 1-bromo-3,7-dimethyloctane (59965-20-7, 72746-96-4, 79434-89-2, 3383-83-3) → 2,6-bis(trimethyltin)-4,8-di(3,7-dimethyl)octyloxybenzo[1,2-b;3,4-b′]dithiophene

Conditions	Yield
Stage #1: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione With sodium hydroxide; zinc In water for 1h; Inert atmosphere; Reflux; Stage #2: 1-bromo-3,7-dimethyloctane With tetrabutylammomium bromide In water for 2h; Inert atmosphere; Reflux;	95.5%

4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) + n-decyl magnesium bromide (17049-50-2) → C20H26O2S2

Conditions	Yield
In toluene at 0 - 20℃; Inert atmosphere;	93.6%

4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) → 4,8-dihydroxybenzo[1,2-b:4,5-b']dithiophene (1357156-35-4)

Conditions	Yield
With sodium tetrahydroborate In ethanol at 90℃; for 12h; Cooling with ice; Inert atmosphere;	92.6%
With sodium tetrahydroborate; ethanol at 0 - 85℃; Inert atmosphere;	91%
With sodium tetrahydroborate; ethanol at 0 - 85℃; Inert atmosphere;	91%

4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) + n-octyne (629-05-0) → 4,8-bis(oct-1-ynyl)benzo[1,2-b:4,5-b']dithiophene

Conditions	Yield
Stage #1: n-octyne With isopropylmagnesium chloride at 20 - 60℃; Stage #2: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione With hydrogenchloride; tin(ll) chloride In water at 20 - 65℃;	90%
Stage #1: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione; n-octyne With isopropylmagnesium bromide Stage #2: With tin(ll) chloride
Stage #1: n-octyne With isopropylmagnesium chloride In tetrahydrofuran at 0 - 60℃; for 1.66667h; Stage #2: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione In tetrahydrofuran at 20 - 60℃; for 2h; Stage #3: With hydrogenchloride; tin(ll) chloride In tetrahydrofuran at 20 - 65℃; for 1h;

4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) + 1,8-dibromonaphthalene (17135-74-9) → C30H12O2S2

Conditions	Yield
With di-tert-butyl(methyl)phosphonium tetrafluoroborate salt; palladium diacetate; potassium carbonate In N,N-dimethyl acetamide at 100℃; for 20h; Inert atmosphere;	90%

4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) + 1-bromo-octane (111-83-1) → 4,8-bis(octyloxy)benzo[1,2-b:4,5-b']dithiophene (1098102-94-3)

Conditions	Yield
Stage #1: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione With sodium hydroxide; zinc In water for 1h; Reflux; Stage #2: 1-bromo-octane With tetrabutylammomium bromide In water for 8h; Reflux;	89.7%
Stage #1: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione With sodium hydroxide; zinc In water for 2h; Inert atmosphere; Reflux; Stage #2: 1-bromo-octane With tetrabutylammomium bromide In water Inert atmosphere; Reflux;	86%
Stage #1: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione With sodium hydroxide; zinc In water for 1h; Reflux; Stage #2: 1-bromo-octane With tetrabutylammomium bromide In water for 12h; Reflux;	74.3%

4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) + methylmagnesium bromide (75-16-1) → 8-hydroxy-8-methylbenzo[1,2-b:4,5-b']dithiophen-4-one

Conditions	Yield
In toluene at 0 - 20℃;	87.5%
In toluene at 0 - 20℃; Inert atmosphere;	87.5%

2-ethylhexyl bromide (18908-66-2) + 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) → 4,8-di(2-ethylhexyloxy)benzo[1,2-b:4,5-b']dithiophene (1160823-77-7)

Conditions	Yield
Stage #1: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione With potassium hydroxide; zinc In N,N-dimethyl-formamide at 80℃; for 48h; Stage #2: 3-bromomethylheptane In N,N-dimethyl-formamide at 80℃; for 24h; Inert atmosphere;	87%
Stage #1: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione With sodium hydroxide; zinc In water at 120℃; for 13h; Stage #2: 3-bromomethylheptane With tetrabutylammomium bromide In water Time;	87%
Stage #1: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione With sodium hydroxide; zinc In water at 120℃; for 13h; Stage #2: 3-bromomethylheptane With tetrabutylammomium bromide In water	87%

(S)-2-ethylhexyl p-toluenesulfonate + 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) → 4,8-bis((S)-2-ethylhexyloxy)benzo[1,2-b:4,5-b']dithiophene

Conditions	Yield
Stage #1: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione With sodium hydroxide; zinc In water for 1h; Reflux; Stage #2: (S)-2-ethylhexyl p-toluenesulfonate With tetrabutylammomium bromide In water for 12h; Reflux;	87%

4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) + 1-dodecylbromide (143-15-7) → 4,8-didodecyloxybenzo[1,2-b:4,5-b’]dithiophene (1044795-04-1)

Conditions	Yield
With tetrabutylammomium bromide; sodium hydroxide; zinc In water at 90℃; for 14h; Temperature;	86%
Stage #1: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione With sodium hydroxide; zinc In water at 90℃; Stage #2: 1-dodecylbromide With tetrabutylammomium bromide In water Temperature;	86%
Stage #1: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione With sodium hydroxide; zinc In water for 1h; Reflux; Stage #2: 1-dodecylbromide With tetrabutylammomium bromide In water for 10h; Reflux;	80%

4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) + 3-ethyl-1-heptyne (55944-43-9) → 4,8-bis-(3-ethyl-hept-1-ynyl)-benzo[1,2-b;4,5-b']dithiophene (1353720-52-1)

Conditions	Yield
Stage #1: 3-ethyl-1-heptyne With n-butyllithium In tetrahydrofuran; hexane at 23℃; for 0.5h; Stage #2: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione In tetrahydrofuran; hexane at 60℃; for 1h; Stage #3: With hydrogenchloride; tin(ll) chloride In tetrahydrofuran; hexane; water at 23 - 60℃; for 1h;	86%
With n-butyllithium; stannous chloride In tetrahydrofuran; hydrogenchloride; water	35%

4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) + 4-bromine-1,2-bis(octyloxy)benzene (291753-67-8) → 4,8-bis(1,2-bis(octyloxy)-4-phenyl)benzo[1,2-b:4,5-b']dithiophene

Conditions	Yield
Stage #1: 4-bromo-1,2-bis(n-octyloxy)benzene With n-butyllithium In tetrahydrofuran; hexane at -78℃; for 1h; Inert atmosphere; Stage #2: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione In tetrahydrofuran; hexane at 20℃; Inert atmosphere; Stage #3: With hydrogenchloride; tin(II) chloride dihdyrate In tetrahydrofuran; hexane; water at 20℃; for 5h; Inert atmosphere;	85%

4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) + 2-hexyldecyl methanesulfonate (111360-16-8) → 4,8-bis((2-hexyldecyl)oxy)benzo[1,2-b:4,5-b’]dithiophene (1254985-73-3)

Conditions	Yield
Stage #1: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione With tetrabutylammomium bromide; sodium hydroxide; zinc In water for 1h; Inert atmosphere; Reflux; Stage #2: 2-hexyldecyl methanesulfonate With zinc In water Inert atmosphere; Reflux;	84%
Stage #1: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione With tetrabutylammomium bromide; sodium hydroxide; zinc In water for 1h; Reflux; Inert atmosphere; Stage #2: 2-hexyldecyl methanesulfonate In water for 2h; Reflux; Inert atmosphere;	72%

4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) + 2-(2'-butyl-1'-octyl)thiophene (1271438-65-3) → 4,8-bis(5-(2-butyloctyl)thiophene-2-yl)benzo[1,2-b;4,5-b']-dithiophene

Conditions	Yield
Stage #1: 2-(2'-butyl-1'-octyl)thiophene With n-butyllithium In tetrahydrofuran; hexane at -78 - 50℃; for 2h; Stage #2: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione In tetrahydrofuran; hexane at 50℃; for 2h; Stage #3: With hydrogenchloride; tin(II) chloride hydrate In tetrahydrofuran; hexane; water at 20℃; for 2h;	84%
Stage #1: 2-(2'-butyl-1'-octyl)thiophene With n-butyllithium In tetrahydrofuran at 0 - 50℃; for 1.25h; Inert atmosphere; Stage #2: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione In tetrahydrofuran at 50℃; for 1h; Inert atmosphere; Stage #3: With hydrogenchloride; tin(II) chloride dihdyrate In tetrahydrofuran; water for 1.5h; Inert atmosphere;	69%
Stage #1: 2-(2'-butyl-1'-octyl)thiophene With n-butyllithium In tetrahydrofuran at 0 - 50℃; for 0.666667h; Inert atmosphere; Stage #2: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione In tetrahydrofuran at 50℃; for 1h; Inert atmosphere; Stage #3: With hydrogenchloride; tin(II) chloride dihdyrate In tetrahydrofuran; water at 20℃; Inert atmosphere;	63%
Stage #1: 2-(2'-butyl-1'-octyl)thiophene With n-butyllithium In tetrahydrofuran at 0 - 50℃; for 1h; Inert atmosphere; Stage #2: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione In tetrahydrofuran at 50℃; for 1h; Inert atmosphere; Stage #3: With hydrogenchloride; tin(II) chloride dihdyrate In tetrahydrofuran; water at 20℃; for 4h; Inert atmosphere;	61%

4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) + 1-Bromopentane (110-53-2) → 4,8-bis(pentyloxy)benzo[1,2-b:4,5-b’]dithiophene

Conditions	Yield
Stage #1: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione With sodium hydroxide; zinc In water for 3h; Reflux; Stage #2: 1-Bromopentane In water at 80℃; for 12h; Reflux; Alkaline conditions;	84%

2-dodecylthiophene (4861-61-4) + 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) → 4,8-bis(2-dodecylthiophene-5-yl)benzo[1,2-b:4,5-b’]dithiophene (1351130-14-7)

Conditions	Yield
Stage #1: 2-dodecylthiophene With n-butyllithium In tetrahydrofuran at -30 - 50℃; for 2h; Inert atmosphere; Stage #2: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione In tetrahydrofuran at 50℃; for 2h; Inert atmosphere; Stage #3: With hydrogenchloride; tin(II) chloride dihdyrate In tetrahydrofuran; water at 20℃; Inert atmosphere;	83%
Stage #1: 2-dodecylthiophene With n-butyllithium In tetrahydrofuran; hexane at -20℃; for 2h; Inert atmosphere; Schlenk technique; Stage #2: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione In tetrahydrofuran; hexane for 1h; Reflux; Inert atmosphere; Schlenk technique; Stage #3: With tin(ll) chloride In tetrahydrofuran; hexane; water at 20℃; for 1h; Reflux; Inert atmosphere; Schlenk technique;	59%
Stage #1: 2-dodecylthiophene; 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione With n-butyllithium In tetrahydrofuran Stage #2: With hydrogenchloride; tin(ll) chloride In water	48%
Stage #1: 2-dodecylthiophene With n-butyllithium In tetrahydrofuran at 0℃; Inert atmosphere; Stage #2: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione Inert atmosphere; Stage #3: With tin(II) chloride dihdyrate Reflux; Inert atmosphere;
Stage #1: 2-dodecylthiophene With n-butyllithium In tetrahydrofuran at 0℃; Inert atmosphere; Stage #2: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione Inert atmosphere; Stage #3: With tin(II) chloride dihdyrate Inert atmosphere;

4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) + 2-(2-ethylhexyl)thiophen (4891-44-5) → 4-(5-(2-ethylhexyl)thiophen-2-yl)-8-(5-(2-ethylhexyl)thiophene-2-yl)benzo[1,2-b:4,5-b']dithiophene (1352642-35-3)

Conditions	Yield
Stage #1: 2-(2-ethylhexyl)thiophen With n-butyllithium In tetrahydrofuran; hexane at 0 - 50℃; for 1h; Inert atmosphere; Stage #2: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione In tetrahydrofuran; hexane at 50℃; for 1h; Inert atmosphere; Stage #3: With hydrogenchloride; tin(ll) chloride In tetrahydrofuran; hexane; water at 20℃; for 2h; Inert atmosphere;	82%
Stage #1: 2-(2-ethylhexyl)thiophen With n-butyllithium In tetrahydrofuran at -30 - 50℃; for 2h; Inert atmosphere; Stage #2: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione In tetrahydrofuran at 50℃; for 2h; Inert atmosphere;	76%
Stage #1: 2-(2-ethylhexyl)thiophen With n-butyllithium In tetrahydrofuran; hexane at -78 - 50℃; for 2h; Stage #2: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione In tetrahydrofuran; hexane at 50℃; for 2h; Stage #3: With hydrogenchloride; tin(II) chloride hydrate In tetrahydrofuran; hexane; water at 20℃; for 2h;	76%

ethyl bromide (74-96-4) + 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) → 4,8-diethoxybenzo[1,2-b:4,5-b′]dithiophene

Conditions	Yield
Stage #1: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione With sodium hydroxide; zinc In water at 130℃; Stage #2: ethyl bromide With tetrabutylammomium bromide In water	82%
Stage #1: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione With sodium hydroxide; zinc In water for 3h; Inert atmosphere; Schlenk technique; Reflux; Stage #2: ethyl bromide With tetrabutylammomium bromide In water for 6h; Inert atmosphere; Schlenk technique; Reflux;	67%

4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) + 4-tert-Butylphenylacetylene (772-38-3) → C34H30S2

Conditions	Yield
Stage #1: 4-tert-Butylphenylacetylene With n-butyllithium In tetrahydrofuran; hexane at -78℃; for 1h; Inert atmosphere; Stage #2: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione In tetrahydrofuran; hexane at 20℃; for 6h; Inert atmosphere; Stage #3: With hydrogenchloride; tin(ll) chloride In tetrahydrofuran; hexane; water Inert atmosphere;	82%
Stage #1: 4-tert-Butylphenylacetylene With n-butyllithium In tetrahydrofuran; hexane at -78℃; for 1h; Inert atmosphere; Stage #2: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione In tetrahydrofuran; hexane at 20℃; for 1h; Stage #3: With hydrogenchloride; tin(ll) chloride In tetrahydrofuran; hexane; water

4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) + methyl iodide (74-88-4) → 4,8-Dimethoxybenzo<1,2-b:4,5-b'>dithiophene (85903-02-2)

Conditions	Yield
Stage #1: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione With sodium hydroxide; zinc In water for 2h; Inert atmosphere; Schlenk technique; Reflux; Stage #2: methyl iodide With tetrabutylammomium bromide for 16h; Inert atmosphere; Schlenk technique; Reflux;	82%

4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) + 4-cyanophenylacetylene (3032-92-6) → C28H12N2S2

Conditions	Yield
Stage #1: 4-cyanophenylacetylene With n-butyllithium In tetrahydrofuran; hexane at -78℃; for 1h; Inert atmosphere; Stage #2: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione In tetrahydrofuran; hexane at 20℃; for 1h; Stage #3: With hydrogenchloride; tin(ll) chloride In tetrahydrofuran; hexane; water	82%

2,3-dihexylthiophene + 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (32281-36-0) → 4,8-bis(4,5-dihexylthiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene (1421924-02-8)

Conditions	Yield
Stage #1: 2,3-dihexylthiophene With n-butyllithium In tetrahydrofuran; hexane at 0 - 50℃; for 1h; Inert atmosphere; Stage #2: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione In tetrahydrofuran at 50℃; for 2h; Stage #3: With hydrogenchloride; tin(II) chloride dihdyrate In tetrahydrofuran; hexane; water at 20℃; for 2h;	81%
Stage #1: 2,3-dihexylthiophene With n-butyllithium In tetrahydrofuran at 50℃; for 2.75h; Cooling with ice; Inert atmosphere; Stage #2: 4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione In tetrahydrofuran at 50℃; for 2.5h; Inert atmosphere; Stage #3: With hydrogenchloride; tin(II) chloride dihdyrate In tetrahydrofuran; water at 20℃; Inert atmosphere;	64.6%

Upstream product

• 498-62-4 3-thiophene carboxaldehyde 
• 73540-75-7 3-thiophenecarboxylic acid,N,N-diethylamide 
• 6007-85-8 1H,3H-thieno[3,4-c]furan-1,3-dione 
• 431-71-0 1,1,1,3,3-pentafluoro-2-propanone 
• 41507-35-1 3-thiophene carboxylic acid chloride 
• 267-65-2 benzo[1,2-b:4,5-b']dithiophene 
• 6007-83-6 2,3-thiophenedicarboxylic acid anhydride 
• 59906-37-5 N,N-dimethyl-3-thiophene carboxamide 
• 109-72-8 n-butyllithium 

Downstream Products

• 1098102-94-3 4,8-bis(octyloxy)benzo[1,2-b:4,5-b']dithiophene 
• 1160823-77-7 4,8-di(2-ethylhexyloxy)benzo[1,2-b:4,5-b']dithiophene 
• 1044795-04-1 4,8-didodecyloxybenzo[1,2-b:4,5-b’]dithiophene 
• 1338083-07-0 C₅₃H₅₈BrNO₇S₃ 
• 1338083-08-1 C₅₄H₅₈BrNO₅S₄ 
• 1338083-09-2 C₅₀H₅₅BrN₂O₆S₂ 
• 1338083-10-5 C₅₆H₅₉BrN₂O₈S₃ 
• 1338083-11-6 C₅₇H₅₉BrN₂O₆S₄ 
• 1338083-06-9 C₄₇H₅₄BrNO₅S₂ 
• 1234306-29-6 4,8-bis(2-ethylhexyl)benzo[1,2-b:4,5-b']dithiophene 
• 1294515-75-5 2,6-dibromo-4,8-bis(octyloxy)benzo[1,2-b:4,5-b']dithiophene 
• 1648615-17-1 C₃₉H₅₃NO₃S₂ 
• 1160823-78-8 2,6-bis(trimethyltin)-4,8-di(2-ethylhexyloxy)benzo[1,2-b:4,5-b']dithiophene 
• 1443120-32-8 4,8-bis(5-(2-butyloctyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene 

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