TY - JOUR
T1 - Synthesis, structures and catalytic properties of iron(iii) complexes with asymmetric N-capped tripodal NO3 ligands and a pentadentate N2O3 ligand
AU - Tong, Lok H
AU - Wong, Yee-Lok
AU - Pascu, Sofia I
AU - Dilworth, Jonathan R
PY - 2008
Y1 - 2008
N2 - A new family of N-capped tripodal NO(3) proligands N,N-bis(2-hydroxy-3,5-di-tert-butylbenzyl)-N-(2'-hydroxy-5'-R-phenyl) amine [H(3)(L(n))] [when R= Me, n = 1; R= (t)Bu, n = 2; R = Cl, n = 3] with different substituents in one of the aryl rings and N, N-bis(2-hydroxy-3-tert-butylbenzyl)-N-(2'-hydroxy-5'-methylphenyl)amine [H(3)(L(4))] were synthesised. The preparation of a new pentadentate proligand N-methyl-N,N',N'-tris(2-hydroxy-3,5-di-tert-butylbenzyl) ethane-1,2-diamine [H(3)(L(5))] with an N(2)O(3) donor set is also reported. Reaction of the proligands [H(3)(L(n))] (n = 1-4) with iron(III) chloride in the presence of base (triethylamine) and 1-methylimidazole (1-Meim) as co-ligand led to the formation of iron complexes of the type [Fe(Ln)(1-Meim)] (n = 1-4) (1-4) respectively, while treatment of the trilithium salt of [H3(L5)] with iron(III) chloride afforded [Fe(L(5))] (5). All complexes were structurally characterised by X-ray crystallography. In complexes 1-4, the ligands form five- and six-membered chelate rings with the iron centres which have distorted trigonal bipyramidal geometry with an N(2)O(3) coordination environment. Complex 5 adopts a similar distorted trigonal bipyramidal geometry also with N(2)O(3) coordination around the iron centre. The catalytic activity of these iron complexes towards epoxidation of styrene was examined.
AB - A new family of N-capped tripodal NO(3) proligands N,N-bis(2-hydroxy-3,5-di-tert-butylbenzyl)-N-(2'-hydroxy-5'-R-phenyl) amine [H(3)(L(n))] [when R= Me, n = 1; R= (t)Bu, n = 2; R = Cl, n = 3] with different substituents in one of the aryl rings and N, N-bis(2-hydroxy-3-tert-butylbenzyl)-N-(2'-hydroxy-5'-methylphenyl)amine [H(3)(L(4))] were synthesised. The preparation of a new pentadentate proligand N-methyl-N,N',N'-tris(2-hydroxy-3,5-di-tert-butylbenzyl) ethane-1,2-diamine [H(3)(L(5))] with an N(2)O(3) donor set is also reported. Reaction of the proligands [H(3)(L(n))] (n = 1-4) with iron(III) chloride in the presence of base (triethylamine) and 1-methylimidazole (1-Meim) as co-ligand led to the formation of iron complexes of the type [Fe(Ln)(1-Meim)] (n = 1-4) (1-4) respectively, while treatment of the trilithium salt of [H3(L5)] with iron(III) chloride afforded [Fe(L(5))] (5). All complexes were structurally characterised by X-ray crystallography. In complexes 1-4, the ligands form five- and six-membered chelate rings with the iron centres which have distorted trigonal bipyramidal geometry with an N(2)O(3) coordination environment. Complex 5 adopts a similar distorted trigonal bipyramidal geometry also with N(2)O(3) coordination around the iron centre. The catalytic activity of these iron complexes towards epoxidation of styrene was examined.
UR - http://www.scopus.com/inward/record.url?scp=50249185581&partnerID=8YFLogxK
UR - http://dx.doi.org/10.1039/b804414g
U2 - 10.1039/b804414g
DO - 10.1039/b804414g
M3 - Article
SN - 1477-9226
VL - 2008
SP - 4784
EP - 4791
JO - Dalton Transactions
JF - Dalton Transactions
IS - 35
ER -