correctness

Yes, it is an example of passive construction.

Thank you for the answer.
But I am a little bit confused because some grammar book suggests that order behaves just like persuade.
And persuade does not permit the passivization of the complement clause, according to that grammar book.
ex. He persuaded the deadline to be imposed by the company. (x)
The company was persuaded to impose the deadline by him.

I think the grammar book is a bit wrong...
Persuade and order are not synonyms, and persuade actually does allow passivisation in the complement clause.

Sentence x is actually incorrect because the action of imposing is opposed to the action of persuading.
Sentence o isn't technically incorrect, but it sounds really unnatural.

The thought could be b

Thank you for the answer.
I think I was too hasty to infer the statement as I wrote in the previous reply.
I should have quoted the proposition verbatim, it was my fault.
Here it is,

* The Americans persuaded the deadline to be imposed by the UN.
...... This shows that the postverbal NP in this pattern is an argument of the verb.
Other verbs that patter

Well, my rewrite of sentence o above would be an example. Yes, I would say those verbs can all be passivised in the complement clause. Again, I would disagree with the grammar book. The sentence they give may be correct, but it sounds really unnatural.

Thank you for your answer. It sheds a lot of light on the topic concerned.

No problem.