Blue Acid Chemistry (10): Fe(bipy)2Bl2.3H2O

Я отвечаю: «Солнце взойдет –

Это ведь тоже немного пожар.

——Солнце взойдёт by DDT

Uhh, I am not away these days, I just met too much difficulties and I failed many many times making something.

This complex could also be transformed into many other things, like K2[Fe(bipy)Bl4] or [Fe(bipy)2Bl2]NO3, but both requires extremely harsh conditions(refluxing for 20h and concentrated HNO3, respectively) so I won't be able to try at least currently.

Fe2+ + 3bipy = [Fe(bipy)3]2+

[Fe(bipy)3]2+ + 2Bl- = bipy + Fe(bipy)2Bl2

2.78g(0.01mol) FeSO4.7H2O and 4.68g(0.03mol) 2,2'-bipyridine(bipy) was put into 400mL water and heated to nearly boiling, where a deep red solution formed.

Then, 10g(0.15mol) KBl was dissolved into 20mL water and added all at once into that solution(Manual said that some HBl is formed, hope not so!). A huge excess is needed as bipy itself is a good ligand. After stirring and cooling down, crystals quickly formed. Wait 1h after fully cooling, filter, wash with water(this product is also slightly soluble so don't try to make the washing water colorless) and dry to collect them.

The product is shiny microcrystals, and if you look carefully, they are needles. Very beautiful.

Yield: 3.43g(72%).

Recrystallization requires concentrated H2SO4 so I won't do.

Mother liquor contains mainly bipy, K2SO4 and KBl, and can be safely disposed with excess amount of bleach or metal salts. Due to the presence of bipy it is hard to turn KBl into useful byproducts. I chose FeSO4, which turn it into a red milk of [Fe(bipy)3]2+, this product and some reduced form of Blue.

Not sure whether the two Bl- are cis or trans, not a big deal for us.