Inorganic Chemistry, Vol.57, No.15, 9215-9222, 2018
A Nitrido-bridged Heterometallic Ruthenium(IV)/Iron(IV) Phthalocyanine Complex Supported by A Tripodal Oxygen Ligand, [Co(eta(5)-C5H5){P(O)(OEt)(2)}(3)](-): Synthesis, Structure, and Its Oxidation to Give Phthalocyanine Cation Radical and Hydroxyphthalocyanine Complexes
Dinuclear iron nitrido phthalocyanine complexes are of interest owing to their applications in catalytic oxidation of hydrocarbons. While nitrido-bridged diiron phthalocyanine complexes are well documented, the oxidationundefined chemistry of heterodinuclear iron(IV) phthalocyanine nitrides has not been well explored. In this paper we report on the synthesis of a heterometallic Fe-IV/Ru-IV phthalocyanine nitride and its oxidation to yield phthalocyanine cation radical and hydroxyphthalocyanine complexes. Treatment of [Fe-II(Pc)] (Pc2- = phthalocyanine dianion) with [Ru-VI (L-oEt)(N)CI2) (L-OEt(- )= [Co(eta(5)-C5H5){P(O)(OEt)(2)}(3)](-)) (1) afforded the heterometallic mu-nitrido complex [CI2(L-OEt)Ru-IV(mu-N)Fe-IV(Pc)(H2O)] (2) that contains an Ru-I(V)= N = Fe(IV )linkage with the Ru-N and Fe-N distances of 1.689(6) and 1.677(6) angstrom, respectively, and Ru-N-Fe angle of 176.0(4)degrees. Substitution of 2 with 4-tert-butylpyridine (Bupy) gave [Cl-2(L-oEt)Ru-IV(mu-N)Fe-IV(Pc)(Bupy)]. The cyclic voltammogram of 2 displayed a reversible Pc-centered oxidation couple at +0.18 V versus Fc(+/0) (Fc = ferrocene). The oxidation of 2 with [N(4-BrC6H4)(3)]SbCI6 led to isolation of the cationic complex [CI2(L-OEt) Ru-IV(mu-N)Fe-IV(Pc.+)- (H2O)][SbCI6](0.85)[SbCI5(OH)](0.15) (2[SbCI6](0.85)[SbCI5(OH)](0.15)), whereas that with PhICI2 yielded the chloride complex [CI2(L-OEt)Ru-IV(mu-N)Fe-IV(Pc.+)CI] (3). Complexes 2[SbCI6](0.85)[SbCI5(OH)](0.15) and 3 have been characterized by X-ray crystallography. The UV/visible spectra of 2(+) (lambda(max) = 515 and 747 nm) and 3 (lambda(max) = 506 and 748 nm) displayed absorption bands that are characteristic of Pc cation radical. The EPR spectrum of 3 showed a signal with the g value of 2.0012 (width = 5G) that is consistent with an organic radical. The spectroscopic data support the formulation of 2(+) and 3 as Ru-IV-Fe-IV Pc cation radical complexes. The reaction of 2 with PhI(CF3CO2)(2) in dried CH2CI2 afforded a mixture of [CI2(L-OEt)Ru-IV(mu-N)Fe-IV(Pc.+)(CF3CO2)] (4) and a hydroxyphthalocyanine complex, [CI2(L-OEt)Ru-IV(mu-N)Fe-IV(Pc-OH)(H2O)](CF3CO2) (5), whereas that in wet CH2CI2 (containing ca. 0.5% water) led to isolation of 5 as the sole product. Complex 4 was independently prepared by salt metathesis of 3 with AgCF3CO2.