Yes, colloquial and a little bit archaic maybe.
Let us separate two constructions: "так и не", which is complicated by itself, and "verb infinitive + same verb in any other form".Уснуть так и не уснул.
The second is just an intensive one (the way to emphasize) and used mainly in contrapositions.
Уснуть - уснул, но не отдохнул.
As for sleeping, I did it, but was unable to relax.