I work for a big company in a research department and am currently interviewing with a 10 people start-up in (roughly) the same industry branch. They're very relaxed and want me to give a scientific presentation during the process and I offered them to give one at my current employer, too, as this could be interesting for both parties (mainly from a scientific perspective, but technically also on a business one). Now that I offered it, I'm unsure if I'm in a conflict of interests here, as it may be interpreted as giving them opportunities just before I am possibly changing my job to them. Did I go too far with that offer? My only intention was to have a scientific exchange.
Did I go too far with that offer?
Yes. It doesn't really matter that much what your intention was here, you have to consider the impression it gives and that's pretty terrible in this case.
Personally, I would regard this as a red flag when it comes to hiring you as you don't appear to be able to correctly separate your personal interests from that of your employer. Try and find a way to undo the offer.
"Did I go too far with that offer?"
No offense but that's a terrible idea you had there
"My only intention was to have a scientific exchange."
Then you should have given a scientific presentation at the company you were interviewing as they have suggested to you.
"..as this could be interesting for both parties.."
This could/will leave a sour taste and an unprofessional impression with both - your current and possible future employer..
What you describe is possible if and only if there are clear benefits to your current employer from this arrangement, they know you are leaving for the new position (and it still makes sense then), and you are senior enough to correctly assess all that jazz. In other words, if you are in a position to build an entire business partnership between the two companies, you might do that.
Most likely, however, this is a terrible idea born of naivety. If you are so careless with your current employer's (potentially) sensitive and business-critical information, who's there to say you won't do the same with your new employer once the day comes? In industrial espionage, one-time payoffs are great but the outcome is essentially career-ending in many, if not most cases. Your case is less drastic, of course, but the same principle applies.