Dissertation

|6.1 Synthesis of the Organic Ligands|
6.1.14 5,10-Dibromo-1H-imidazo[4,5-f][1,10]phenanthroline - Br 2 ip
In a round bottom flask 368 mg (1.0 mmol) of 3,8-dibomo-1,10-phenanthrolindione, 280 mg
(2.0 mmol) of hexamine and 385 mg (5.0 mol) of ammonium acetate were suspended in 10 ml
of glacial acetic acid. After refluxing the resulting mixture for two hours, the volatiles were
removed under reduced pressure. The resulting solid was dissolved in a small amount of water
and neutralized with ammonia. Stirring this mixture over night yielded an off-white precipitate.
The solid was filtered off, and washed twice with ethanol and ether and was dried under vacuum.
Yield: 265 mg (700 µmol, 70%) of a light yellow powder.
10
9
N
N
Br
6
5
Br
4
11
H
N
N
Br 2 ip
2
1
H-NMR (400 MHz CDCl 3 /CF 3 COOD): δ = 12.78 (s, 1H (NH) ), 9.36 (d, 1H (A) ,
4
J = 2.0 Hz), 9.34 (d, 1H (A) , 4
J = 2.0 Hz), 9.11 (d, 1H (C) , 4
J = 2.1 Hz), 8.90 (s,
1H (D) ), 8.37 (d, 1HC, 4 J = 2.1Hz) ppm. 1 H-NMR (400 MHz, DMSO-d) δ = 9.06
(d, 2H (A) , 4 J = 2.3 Hz), 9.00 (d, 2H (C) , 4 J = 2.3 Hz), 8.51 (s, 1H (D) ) ppm.
6.1.15 1,3-Dibenzyl-5,10-dibromo-1H-imidazo[4,5-f][1,10]phenanthrolinium bromide -
Br 2 bbip
According to method L2, 250 mg of Br 2 ip and 55 mg of sodium hydride (60% in paraffin) were
suspended in 15 ml of dry DMF and were reacted for 30 minutes in the ultrasonic sound bath
until the imidazolide was dissolved. Then, 200 µl of benzylbromide were added and the reaction
mixture was stirred for two hours. After the reaction the typical color change from dark brown into
a light brown was observed and 300 µl of benzylbromide were added according to method L3. One
NMR-sample was taken inbetween and analyzed. Without isolation of the intermediately formed
monoalkylated product, the mixture was stirred over night at 80°C. The formed yellow precipitate
(product) was collected and washed with ether. Complete removal of the volatiles of the organic
phase in high vacuum gave additional fraction. The residue was dissolved in chloroform, filtrated
and washed with water in an extraction funnel. And the combined organic layers were dried with
Na 2 SO 4 . Removal of the solvent gave a yellow powder. Overall yield 57% (mg, µmol) with respect
to Br 2 ip.
1
H-NMR (400 MHz DMSO-d 6 , intermediately formed Br 2 bip) δ = 9.11 (d, 1H (A) , 4 J = 2.4 Hz), 9.06
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