Coordination Chemistry and Organic Synthesis Utilizing Cycloalkane-1,2-dithiol

Synthesis of Titanium(IV) and Zirconium(IV) Complexes with an [OSSO]-Type Bis(phenolate) Ligand Bearing a trans-Cyclohexane-1,2-diyl Ring and 1-Hexene Polymerization

“…Observation of Zr Cation. To obtain some insights into the difference in activity between 4/B(C 6 F 5 ) 3 7 and 11/B(C 6 F 5 ) 3 in 1-hexene polymerization, we measured 1 H, 13 C, and 19 F NMR of the zirconium cation 12 þ [B(CH 2 Ph)(C 6 F 5 ) 3 ] À generated from 11, which is the starting species for the coordination polymerization of 1-olefins, 17 and compared them with those of the corresponding zirconium cation 13 þ [B(CH 2 Ph)(C 6 F 5 ) 3 ] À (Chart 4)…”

“…Ar) ppm. 19 In 12 þ and 13 þ , benzyl ligands would have η 2 coordination to the zirconium cation center, similar to that in reported group 4 metal, cationic complexes, on the basis of the 1 J CÀH value (143 Hz) for the benzyl carbon (δ 72.3) of 12 þ . 18,20 Okuda and co-workers observed a zirconium cation generated from 3 (L = CH 2 Ph) by treatment with B(C 6 F 5 ) 3 in C 6 D 5 Br, albeit not in a clean form, where the 1 H NMR spectrum showed an apparent C 2 -symmetric species above 10 °C.…”

“…dihedral angles were 159.4 and 44.8°, respectively. For reference, although the chelation ring sizes and ligands (L) are different, the corresponding values in complexes having the same relative configuration are reportedly 158.50 (19) and 53.8(5)°for (Λ,R,R)-3 (L = Cl) and 159.6(1) and 48.3(3)°for (Λ*,R*,R*)-3 (L = CH 2 Ph, where the tBu group para to phenoxido oxygens is replaced by a Me group). 5 While the apical OÀTiÀO bond angles are almost similar, the SÀCÀCÀS dihedral angle in (Δ*, S*,S*)-9 is substantially smaller than those in the reference complexes.…”

“…The Δδ (|δ m-F À δ p-F |) value was 2.8 ppm, which indicates weak coordination between [B(CH 2 Ph)(C 6 F 5 ) 3 ] À and the zirconium cation center, 18 as observed in 13 þ [B(CH 2 Ph)(C 6 F 5 ) 3 ] À . 7,19 Interestingly, the 1 H NMR spectrum indicated a clean formation of a single zirconium cation with C 1 symmetry (12 þ [B(CH 2 Ph)(C 6 F 5 ) 3 ] À ). Thus, four singlets due to t-Bu groups were observed at δ 1.28, 1.32, 1.53, and 1.61 ppm ( Figure 8a) and three pairs of two doublets due to three benzyl groups were observed at δ 2.51 (d, J = 9.3 Hz, ZrCH 2 Ph), 2.83 (d, J = 9.3 Hz, ZrCH 2 Ph), 3.30 (d, J = 11.5 Hz, SCH 2 Ar), 3.40 (d, J = 12.3 Hz, SCH 2 Ar), 3.50 (d, 12.3 Hz, SCH 2 Ar), and 3.55 (d, J = 11.5 Hz, SCH 2 Ar) (Figure 8b).…”

Recent advances in the chemistry of Group 4 metal complexes incorporating [OSSO]-type bis(phenolato) ligands as post-metallocene catalysts

“…The cationic titanium methyl complex 21 + was isolated as a Lewis-base stabilized form by Okuda et al 46 In the case of cationic zirconium complex, the cationic zirconium benzyl complex 22 + $[PhCH 2 B(C 6 F 5 ) 3 ] À , prepared by treatment of 17 with B(C 6 F 5 ) 3 in C 6 D 6 , was also observed by 1 H and 19 F NMR spectroscopies (Scheme 24). 47 In the 19 zirconium cation with the C 1 symmetry. Thus, four singlets due to tert-butyl groups and three pairs of two doublets due to three benzyl groups appeared inequivalently.…”