The reaction of Cp*2Yb(THF)2 with an equimolar amount of 7,7,8,8-tetracyanoquinodimethane (TCNQ) affords the Yb(III) complex [Cp*2Yb(CH3CN){(μ-CN)2C(C6H4)C(CN)2(C5Me5)}]2, containing a monoanionic polycyano ligand arising from one-electron reduction of TCNQ and the coupling of its methylidene carbon with the allylic carbon atom of a Cp* fragment. Reaction of Cp*2Yb(THF)2 with 1,2,4,5-tetracyanobenzene (TCNB) in a 1:1 molar ratio results in oxidation of the ytterbium atom and the formation of the Yb(III) complex [Cp*2Yb{(μ-CN)2(C6H4)(CN)2}]2the first example of the dianionic π-dimer [TCNB2]2− participating in μ:η4 bonding with two metal centers.

A new route to the octacyanoporphyrazine framework based on the interaction of metal sandwich pi-complexes with TCNE has been developed.

The reaction of ytterbocene (C 5 H 4 Me) 2 Yb(THF) with 2 equiv of N-2,6-diisopropylphenylimino-2-pyridine (Ipy) occurs with oxidative cleavage of one Yb-Cp bond and oxidation of the ytterbium(II) ion and affords the half-sandwich Ybwas synthesized by the metathesis reaction of (C 5 Me 5 )GdCl 2 (THF) 3 with a 2-fold molar excess of [Ipy •-]K þ in THF. The structures of all complexes were proved by the X-ray single-crystal diffraction studies. The investigation of magnetic properties of complexes [LnCp{(2,6-i-Pr 2 C 6 H 3 NCH(C 5 H 4 N) •-} 2 ] (Cp = C 5 H 4 Me, C 5 Me 5 , C 9 H 7 ; Ln = Yb, Gd) in the temperature region 2-300 K revealed the presence of two types of antiferromagnetic interactions between the paramagnetic centers: between the Ln 3þ ion and both radicals and between two radicals.