Premium
Synthesis and Characterisation of Novel (Guanidine)manganese Complexes and Their Application in the Epoxidation of 1‐Octene
Author(s) -
Wortmann Ramona,
Flörke Ulrich,
Sarkar Biprajit,
Umamaheshwari Venkatesan,
Gescheidt Georg,
HerresPawlis Sonja,
Henkel Gerald
Publication year - 2011
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201000836
Subject(s) - chemistry , manganese , guanidine , electron paramagnetic resonance , catalysis , pyridine , medicinal chemistry , crystallography , peracetic acid , stereochemistry , hydrogen peroxide , organic chemistry , physics , nuclear magnetic resonance
The synthesis of manganese complexes of the guanidine–pyridine hybrid ligands DMEGqu ( L1 ) and TMGqu ( L2 ) is reported. The complexes [Mn 2 (μ‐Cl) 2 Cl 2 (DMEGqu) 2 ] ( C1 ), [Mn 2 (TMGqu) 2 (μ‐Cl) 2 Cl 2 ] ( C2 ), [Mn 3 (DMEGqu) 2 (μ‐CH 3 COO) 6 ] ( C3 ), [Mn 3 (TMGqu) 2 (μ‐CH 3 COO) 6 ] ( C4 ) and [Mn 2 (DMEGqu) 2 (μ‐CF 3 SO 3 ) 2 (CF 3 SO 3 ) 2 (H 2 O) 2 ] ( C5 ) have been structurally characterised. For C1 and C2 dinuclear chlorido‐bridged motifs have been found and trinuclear acetato‐bridged motifs for C3 and C4 which represent the first trinuclear (guanidine)manganese compounds reported so far. The dinuclear triflato complex C5 exhibits a unique Mn(μ‐CF 3 SO 3 ) 2 (CF 3 SO 3 ) 2 unit. EPR measurements of C1 and C2 indicate that in solution the dinuclear complexes decompose to mononuclear species. Contrastingly, the EPR spectra of C3 and C4 show that these acetato complexes remain polynuclear in CH 3 CN. The chlorido and acetato complexes convince by their high stability towards air. All complexes reported herein were screened regarding their activity in the epoxidation of 1‐octene with peracetic acid. It could be proven that these compounds are able to act as catalysts in this reaction already under mild conditions. Kinetic measurements exhibit that the epoxidation reaction proceeds on a time scale interesting for industrial application.