title: Tuning the stability and reactivity of metal-bound alkylperoxide by remote site substitution of the ligand.
abstract: An alkylperoxonickel(II) complex with hydrotris(3,5-diisopropyl-4-bromo-1-pyrazolyl)borate, [Ni(II)(OOtBu)(Tp(iPr2,Br))] (3 a), is synthesized, and its chemical properties are compared with those of the prototype non-brominated ligand derivative [Ni(II)(OOtBu)(Tp(iPr2))] (3 b; Tp(iPr2)=hydrotris(3,5-diisopropyl-1-pyrazolyl)borate). Same synthetic procedures for the prototype 3 b and its precursors can be employed to the synthesis of the Tp(iPr2,Br) analogues. The dimeric nickel(II)-hydroxo complex, [(Ni(II)Tp(iPr2,Br))(2)(mu-OH)(2)] (2 a), can be synthesized by the base hydrolysis of the labile complexes [Ni(II)(Y)(Tp(iPr2,Br))] (Y=NO(3) (1 a), OAc (1 a')), which are obtained by the metathesis of NaTp(iPr2,Br) with the corresponding nickel(II) salts, and the following dehydrative condensation of 2 a with the stoichiometric amount of tert-butylhydroperoxide yields 3 a. The unique structural characteristics of the prototype 3 b, that is, highly distorted geometry of the nickel center and intermediate coordination mode of the O--O moiety between eta(1) and eta(2), are kept in the brominated ligand analogue 3 a. The introduction of the electron-withdrawing substitutents on the distal site of Tp(R) affects the thermal stability and reactivity of the nickel(II)-alkylperoxo species.
authors.affiliation: Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama 221-8686, Japan. hikichi@kanagawa-u.ac.jp
authors.forename: Shiro
authors.initials: S
authors.lastname: Hikichi
authors.forename: Chiho
authors.initials: C
authors.lastname: Kobayashi
authors.forename: Michito
authors.initials: M
authors.lastname: Yoshizawa
authors.forename: Munetaka
authors.initials: M
authors.lastname: Akita
mesh_terms: D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry; D018360:Crystallography, X-Ray; D008024:Ligands; D008670:Metals / Q000737:chemistry*; D008968:Molecular Conformation; D009532:Nickel / Q000737:chemistry; D010084:Oxidation-Reduction; D010545:Peroxides / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D008024:Ligands; D008670:Metals; D010545:Peroxides; D009532:Nickel