If finding VC-One or VC-Two is something that OldCo truly could not have physically accomplished without Charlie's help/introduction, and OldCo was looking for

If finding VC-One or VC-Two is something that OldCo truly could not have physically accomplished without Charlie's help/introduction, and OldCo was looking for investors, then yes, OldCo does owe Charlie something. By accepting investment, OldCo has accepted this responsibility. If finding VC-One or VC-Two is something that OldCo could have reasonably expected to accomplish on its own, then Charlie should be thanked for the intro (possibly including a night of beers and wings) but no other monetary compensation is required. Personally, though, I would be inclined more towards the sharing. It's a friends thing. I would not feel ethically bound to do so though, so if Charlie approached me all pissed off and righteous about it, he can kiss my silk-wrapped butt.