10.1021/ic701370t.s003 Ad Cohen Ad Cohen Adi Yeori Adi Yeori Israel Goldberg Israel Goldberg Moshe Kol Moshe Kol Group 4 Complexes of a New [OSSO]-Type Dianionic Ligand. Coordination Chemistry and Preliminary Polymerization Catalysis Studies American Chemical Society 2007 S analogue tetradentate dianionic group 4 Complexes OSSO C 2 symmetry ethylenedithiol core bridged methylene groups ONNO Coordination Chemistry NMR Preliminary Polymerization Catalysis Studies C 2 ligand precursor ligand features stereoirregular polymer 2007-10-01 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Group_4_Complexes_of_a_New_OSSO_Type_Dianionic_Ligand_Coordination_Chemistry_and_Preliminary_Polymerization_Catalysis_Studies/2983282 A straightforward synthesis of a new type of tetradentate dianionic [OSSO]-type ligand is described. This ligand features an ethylenedithiol core bridged via methylene groups to substituted phenols, thus representing an S analogue of the [ONNO]-type Salan ligands. The [OSSO]H<sub>2</sub> ligand precursor reacted with titanium(IV) isopropoxide and with zirconium(IV) <i>tert</i>-butoxide to give the corresponding [OSSO]−M(OR)<sub>2</sub> complexes, which formed as single <i>C</i><sub>2</sub>-symmetric isomers but were fluxional according to variable-temperature NMR. An X-ray structure of [OSSO]−Zr(O-t<i>-</i>Bu)<sub>2</sub> supported the <i>fac</i><i>−</i><i>fac</i> wrapping mode of the ligand. The dibenzyl complex [OSSO]−Zr(bn)<sub>2</sub> that was obtained by a reaction between the ligand precursor and tetrabenzylzirconium was found to be an active 1-hexene polymerization catalyst upon activation with B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>, leading to a stereoirregular polymer despite its <i>C</i><sub>2</sub> symmetry.