Not addressing the jeans, for the moment, a tie with a dress shirt, minus the jacket, can never look inherently wrong as men have for generations appeared like this around the workplace or somewhat dressy setting when it is deemed to be unforcomforable to keep the jacket on. As for the tie with jeans, I guess it's become a somewhat acceptible sporty and youthful look for guys for a certain kind of party, bar, club, visiting, etc. Part of the vocabularly is, indeed, narrow and simple tie, and a more sporty sort of long sleeve shirt - e.g. plaid, checks, more prominent stripes, etc. Again - it must be a long sleeve shirt. And obviously the jeans should be in decent condition.