Spells with a free hand

[sword n' board]

I know that you can let go of a two-handed weapon to cast a spell and grab a hold of it again (according to a FAQ) but could you hold a two-handed weapon in one hand and cast inflict wounds with the hand?

[Sindalla]

I don't see why not. Nothing says you can't "hold" a weapon unintended for your size in one hand. It just says you can't effectively wield it, so if you let go, and cast a spell, no swinging that sword for the round.

[Magda Luckbender]

If you land the melee touch attack you can then re-grasp your two handed weapn and, thus, will be able to take AoOs before your next round. If you hold the charge then you can't re-grasp the weapon, do not threaten, and thus will not be able to take any AoOs before your next round.