title: Ferrocene-Based Tris(1-pyrazolyl)borates: A New Approach to Heterooligometallic Complexes and Organometallic Polymers Containing Transition Metal Atoms in the Backbone.
abstract: Starting from mono- and bifunctional ferrocene-based tris(1-pyrazolyl)borates, a novel route to oligonuclear complexes is presented, which incorporates transition metal centers differing substantially in their chemical nature. Both binuclear organometallics FcB(pz)(3)ML(n)() (Fc: ferrocenyl. pz: 1-pyrazolyl. ML(n)(): Tl, 1-Tl; Mo(CO)(3)Li, 1-MoLi; Mo(CO)(2)(eta(3)-methylallyl), 1-Mo; ZrCl(3), 1-Zr) and trinuclear complexes 1,1'-fc[B(pz)(3)ML(n)()](2) (fc: ferrocenylene. ML(n)(): Tl, 2-Tl; Mo(CO)(3)Li, 2-MoLi; Mo(CO)(2)(eta(3)-methylallyl), 2-Mo) have been prepared. The trinuclear compound [FcB(4-SiMe(3)pz)(3)](2)Fe, 1-FeSi, has been investigated as a model system for organometallic coordination polymers, consisting of the bifunctional linker 1,1'-fc[B(pz)(3)](2)(2)(-) and transition metal ions M(n)()(+). X-ray crystallography shows 1-Tl to establish a polymeric structure in the solid state, while 1-Mo features the usual tridentate coordination mode of the scorpionate ligand (C(25)H(25)BFeMoN(6)O(2); a = 8.756(1) Å, b = 12.154(1) Å, c = 12.927(1) Å, alpha = 105.26(1) degrees, beta = 102.29(1) degrees, gamma = 105.09(1) degrees; triclinic space group P&onemacr;; Z = 2). With the exception of 1,2-Tl, the anodic oxidation of the ferrocene moiety is generally reversible; cyclic voltammetry measurements indicate the two Mo centers in 2-Mo and the two Fc moieties in 1-FeSi to be noncommunicating.
authors.affiliation: Anorganisch-chemisches Institut der Technischen Universität München, Lichtenbergstrasse 4, D-85747 Garching, Germany, and Universita di Siena, Dipartimento di Chimica, Pian dei Mantellini 44, 53100 Siena, Italy.
authors.forename: Fabrizia
authors.initials: F
authors.lastname: Fabrizi De Biani
authors.forename: Frieder
authors.initials: F
authors.lastname: Jäkle
authors.forename: Michael
authors.initials: M
authors.lastname: Spiegler
authors.forename: Matthias
authors.initials: M
authors.lastname: Wagner
authors.forename: Piero
authors.initials: P
authors.lastname: Zanello