Okay, so the Ti(cat)3H2 complex presumably has one C6H4O2(2-) ligand and two C6H4(OH)O- ligands. The protons on those ligands aren't going to show up
well on X-ray crystallography (unless resolution has improved a lot since I last did a structure), and I'd expect them to get broadened to heck in 1H
NMR.
To me (and bear in mind that I'm not a titanium chemist), the fact that it's far less soluble in water than the triethylammonium salt is simply
because it's a neutral complex rather than an ionic one. It doesn't necessarily mean that it's polymeric.
If you really want to find out where the protons are, I'd suggest making a complex with one equivalent of catechol and two equivalents of
methoxyphenol, and see where the methyls end up, and if that structure is spectrally similar to the one with protons. |