Bis(cyclopentadienyl) lanthanide benzylthiolate: synthesis, molecular structure and catalytic property for ε-caprolactone –polymerization

ABSTRACT

Reaction of LnCl₃ first with three equivalent of C₅H₅Na in THF, then with one equivalent of benzyl mercaptan, led to complexes of [(C₅H₅)₂Ln(SCH₂Ph)]₂ (Ln = Sm(1), Yb(2)), being characterized by infrared spectra, elemental analyses and X-ray crystallography for 2. Complex 2 is a dimer with two thiolate ligands as bridging groups in eight coordinate. The Yb-S(benzyl) bonds in 2 (2.703(19) and 2.719(2) Å, respectively) were longer than the Yb-S(aryl) bonds (about 2.640 Å) in analogous complexes. The catalytic property for the polymerization of ε-caprolactone by 1 and 2 was studied. Similar experiment was also made with [(C₅H₅)₂Ln(SPh-p-CH₃)(THF)]₂ (Ln = Sm(3), Yb(4)) for comparison. It was found that complex 2 showed the activity best, and the activity decreased in the order of 2 > 3 > 1 > 4. When [ε-CL]₀/[Ln] was 500 and the polymerization temperature was 35°C, complex 2 catalyzed the polymerization in living character, which could not be achieved by lanthanide arylthiolates such as 3 and 4.

GRAPHICAL ABSTRACT

KEYWORDS:

• Lanthanide
• thiolate
• caprolactone
• catalytic activity

Disclosure statement

No potential conflict of interest was reported by the authors.