I have recently come across the following expression:
(они) попрали даже то, что ими диктуется о смысле жизни. (they) trampled even what they dictated about the meaning of life.
It made me wonder: What is the PP о смысле жизни dominated by?
In order to understand it, I considered the expression where the PP is definitely a part of D/NP
Он купил книгу о Х (He bought a book about X)
and made it an embedded clause with wh-movement such that only книгу undergoes movement which resulted in
*Я знаю, что́ он купил о Х (I know what he bought about X)
which is ungrammatical which led me to the conclusion that N' (or N if we take the PP to be a complement in this case) cannot be wh-moved and if there is movement, the PP is then dominated by VP.
The question is: Can you please reference any literature accounting for this phenomenon?