Abstract: Using EPR spectroscopy, high valence Mn(salen) complexes were monitored in MnIII(salen)/isobutyraldehyde/O2 and MnIII(salen)/pivalaldehyde/O2 catalytic systems in the absence and in the presence of N-methylimidazole (N-Me-Imd), where MnIII(salen) (1) is (S,S)-(+)-N,N′-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediamino-manganese(III) chloride. Interaction of 1 with aliphatic aldehydes in the presence of O2 was found to give a mixture of oxo manganese(IV) species L1(salen)MnIV=O (2) with various axial ligands L1 (L1=Cl−, RCOO−). They display EPR signals having close g values of ca. 5.2 with resolved hyperfine structures from one manganese (A=75 G, Full-size image (<1 K), I=5/2). In the presence of N-Me-Imd, new manganese(IV) complexes were detected. The first one was shown to be an antiferromagnetically coupled mixed-valence [(salen)MnIV(μ2-O)2MnIII(salen)]− dimer having 16-line EPR signal at g=2. The second one is probably (salen)MnIV(OOCOR)N-Me-Imd acylperoxo complex (2) (g=4.2 (R=CH(CH3)2), or g=4.7 (R=C(CH3)3), unresolved manganese hyperfine structure). Possible roles of each complex in the enantioselective alkene epoxidations are discussed.

Cite: Bryliakov K.P. , Kholdeeva O.A. , Vanina M.P. , Talsi E.P.
Role of MnIV Species in Mn(salen) Catalyzed Enantioselective Aerobic Epoxidations of Alkenes: An EPR Study
Journal of Molecular Catalysis A: Chemical. 2002. V.178. N1-2. P.47-53. DOI: 10.1016/S1381-1169(01)00296-5 WOS Scopus РИНЦ ANCAN OpenAlex

Dates:

Submitted:	Jan 10, 2001
Accepted:	Jun 25, 2001
Published online:	Dec 28, 2001
Published print:	Jan 23, 2002

Identifiers:

Web of science:	WOS:000173274500007
Scopus:	2-s2.0-0037160313
Elibrary:	13405725
Chemical Abstracts:	2002:6187
Chemical Abstracts (print):	136:294429
OpenAlex:	W2078367553

Citing:

DB	Citing
Web of science	45
Scopus	48
Elibrary	48
OpenAlex	46

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