Abnormal N-heterocyclic carbene main group organometallic chemistry: a debut to the homogeneous catalysis

Tamal K Sen,Swadhin K Mandal,Arup Mukherjee,Bholanath Maity,Samaresh Chandra Sau,Pradip Kumar Hota,Debasis Koley

doi:10.1039/c3dt51802g

Abstract

Abnormal N-heterocyclic carbene (aNHC) adducts of zinc(II) (1) and aluminum(III) (2) were synthesized. The compounds were characterized by NMR spectroscopy and elemental analysis. The solid state structures of these complexes (1 and 2) were determined by single crystal X-ray study. Furthermore, these organozinc and organoaluminum adducts (1 and 2) were tested for the ring opening polymerization of cyclic esters. These adducts were found to be quite efficient catalysts for the polymerization of cyclicesters such as rac-lactide (rac-LA), ε-caprolactone (ε-CL), and δ-valerolactone (δ-VL). Furthermore, aNHC zinc adduct has been used as catalyst for the synthesis of a tri-block copolymer.

Highlights

The carbenes have been considered as important species in organic chemistry ever since the first evidence of their existence
Single point calculations were performed of the optimized geometries using BP86 functional incorporating higher basis sets (TZVP) for all atoms
Carbene salt was prepared according to the literature procedure.[6] ε-CL and δ-VL were purchased from Sigma-Aldrich and dried over freshly ground CaH2 and distilled before use

Summary

Introduction

The carbenes have been considered as important species in organic chemistry ever since the first evidence of their existence. Single point calculations were performed of the optimized geometries using BP86 functional incorporating higher basis sets (TZVP) for all atoms. For NBO study we have done a single-point calculation of the optimized structures of 1 and 2 with replacing the phenyl substituents with methyl groups.

Results

Conclusion