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Molybdenum(II) Complexes with α‐Diimines: Catalytic Activity in Organic and Ionic Liquid Solvents
Author(s) -
Saraiva Marta S.,
Nunes Carla D.,
Félix Vítor,
Ribeiro Ana P. C.,
Castro Carlos Nieto,
Calhorda Maria José
Publication year - 2018
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.201800700
Subject(s) - chemistry , diimine , ionic liquid , catalysis , dichloromethane , chemoselectivity , medicinal chemistry , cyclooctene , trifluoromethanesulfonate , ionic bonding , molybdenum , stereochemistry , solvent , polymer chemistry , organic chemistry , ion
The new [MoX(η 3 ‐C 3 H 5 )(CO) 2 (α‐diimine)] complexes with: (i) X = Br or triflate and α‐diimine = 1,10‐phenanthroline (phen) and dipyridophenazine (dppz); and (ii) X = Br and α‐diimine = phen and dppz, with several substituents, are synthesized and characterized. The structures of [MoBr(η 3 ‐C 3 H 5 )(CO) 2 (Cl‐phen)] and [Mo(CF 3 SO 3 )(η 3 ‐C 3 H 5 )(CO) 2 (dppz)] are determined by using single‐crystal X‐ray diffraction. These and three complexes of 2,2′‐bipyridyl (bpy), and its two derivatives with Me and t Bu substituents, are tested in the homogeneous catalytic epoxidation of several olefins in dichloromethane, exhibiting, in general, a good selectivity towards the respective epoxide and relatively low TOFs. For the first time, the oxidation of cis ‐cyclooctene with some of these catalysts is also conducted in a variety of room‐temperature ionic liquids (RTILs). In the presence of [MoBr(η 3 ‐C 3 H 5 )(CO) 2 (phen)], the conversions, in general, increase, compared with the reactions in organic solvents. Interestingly, different chemoselectivity is found when [C 6 mim][Ntf 2 ] and [C 2 mim][FAP] are used with diol (24–26 %). On the other hand, [MoBr(η 3 ‐C 3 H 5 )(CO) 2 (L)] (L = Me‐phen or dppz) exhibits much lower conversions in the RTILs tested than in common organic solvents.