Synthesis and Application of New Salan Titanium Complexes in the Catalytic Reduction of Aldehydes

Reactions of Heteroallenes with Salan-based Ti(IV) Complexes: A Joint Experimental and Computational Study

The reaction of Ti(NMe2)4 with the salan ligand precursor H2N2O2H2 led to the formation of [(L*)Ti(NHMe2)2] (L*=N2O2 4-) that forms [(H2N2O2)TiCl2] upon reaction with two equiv. of Me3SiCl. [(L*)Ti(py)2] was obtained from the reaction of [Ti(NtBu)Cl2(py)3] with the sodium salt H2N2O2Na2. Treatment of [(L*)Ti(NHMe2)2] with two equiv. of tBuNCO led to the insertion of the isocyanate molecules into the Ti-Nsalan bonds with the formation of [{L*(N(tBu)CO)2}Ti]. Conversely, the reaction of [(H2N2O2)Ti(OiPr)2] with two equiv. of tBuNCO led to the insertion of one isocyanate molecule into a Ti-Nsalan bond with the formation of [{(HN2O2)(N(tBu)CO)}Ti(OiPr)]. Computational studies were performed to gain insight into the reactivity of isocyanates with salan-based Ti(IV) complexes.

6,6′-((Ethane-1,2-diylbis(azanediyl))bis(methylene))bis(2,4-bis(2-phenylpropan-2-yl)phenolate)zirconium(IV) Dichlorido

The salan zirconium complex of formula [(H2N2O2)ZrCl2] (H2N2O2H2 = HOPh’CH2NH(CH2)2NHCH2Ph’OH, where Ph’ = 2,4-(CMe2Ph)C6H2) was synthesized and fully characterized by NMR and single-crystal X-ray diffraction. The solid-state molecular structure of [(H2N2O2)ZrCl2] shows distorted octahedral geometry around the zirconium center with the salan ligand adopting a β-Λ-cis conformation.