title: One Step Forward to "Stapled" Bis(phthalocyanine) Metal Complexes: Synthesis, Characterization, and Redox Properties of Bis(phthalocyaninato)niobium(IV). X-ray Crystal Structure of the Monoelectronically Oxidized Species [Pc(2)Nb](I(3))(I(2))(0.5)(ClNP)(3.5) (ClNP = 1-Chloronaphthalene).
abstract: Bis(phthalocyaninato)niobium(IV) has been prepared and isolated as a monosolvate, [Pc(2)Nb].ClNP (ClNP = 1-chloronaphthalene). It is a light-brown, stable-to-air Nb(IV) (d(1)) paramagnetic sandwich-like species, which, upon oxidation by I(2) under mild conditions, undergoes a metal-centered monoelectronic oxidation to give the diamagnetic Nb(V) (d(0)) [Pc(2)Nb](+) fragment, with formation of saltlike species of formula [Pc(2)Nb](I(3))(I(2))0.5(ClNP)(3.5) (I). The structure of I has been elucidated by single-crystal X-ray work. Crystals are triclinic: formula C(64)H(32)N(16)Nb.I(3).0.5I(2).3.5C(10)H(7)Cl, M = 2194.8, a = 17.702(3) Å, b = 18.708(3) Å, c = 13.504(2) Å, V = 4267.5(13) Å(3), alpha = 106.00(2) degrees, beta = 93.39(2) degrees, gamma = 83.26(1) degrees, Z = 2, space group P&onemacr;. The structure of the [Pc(2)Nb](+) fragment, "stapled" by two inter-ligand C-C sigma bonds (C11A-C11B and C31A-C31B = 1.574(15) Å), together with its color and UV-visible spectral behavior, allows a straightforward assignment of the same "stapled" structure to the unoxidized [Pc(2)Nb]. The present niobium sandwiched materials reiterate the peculiar structural findings shown only by the previously reported [Pc(2)Ti].
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Roma "La Sapienza", Roma, Italy, and Istituto di Strutturistica Chimica, Università di Parma, Parma, Italy.
authors.forename: Maria Pia
authors.initials: MP
authors.lastname: Donzello
authors.forename: Claudio
authors.initials: C
authors.lastname: Ercolani
authors.forename: Angiola
authors.initials: A
authors.lastname: Chiesi-Villa
authors.forename: Corrado
authors.initials: C
authors.lastname: Rizzoli