Until right now, I was very sure that the formulation (we are) open to discuss is kind of idiomatic. Now I read a text that (as I have been told) has been checked by a native speaker of English and stumbled over this:
We are open to discussing the opportunities with you.
I would have written
We are open to discuss the opportunities with you.
instead.
Before I am making a fool out of myself by wrongly correcting a native speaker:
Those both seem grammatically fine to me, but I do not think the first version is normally used. Could you help me find out, if I am right?
Answer
The to in the idiom open to is a preposition, not an ‘infinitive marker’, so it requires a nominal entity as object of the preposition:
My door is open to [anyone who needs to speak with me].
We are open to [whatever proposal you wish to put forward].
The floor is now open to [discussion of this motion].
When you want to use a subordinate clause—a verb with its arguments—as the object, this idiom requires a gerund clause
We are open to [discussing the opportunities with you].
Expressions which employ the preposition to to head NP complements will usually not license infinitive complement clauses, because this creates an awkward ambiguity in the use of to.
Attribution
Source : Link , Question Author : skymningen , Answer Author : StoneyB on hiatus