The synthesis and characterization of a technetium(III) isodiazene complex. The X-ray crystal structure of [TcCl 3(N=NPh 2) (PPh 3) 2

Abstract

The reaction of the Te(V) complex (Bu 4N)[TcOCl 4] with excess Ph 2NNH 2·HCl and PPh 3 in refluxing MeOH yields [TcCl 3(N=NPh 2)(PPh 3) 2]. The IR spectrum of the crystalline product shows a medium intensity band at 1092 cm −1, which is assigned to v(Tc=N) from the isodiazene core. The FAB(+) mass spectrum shows the protonated parent ion of 914 m/ z and the peak associated with the loss of a chloride from the parent ion of 878 m/z. The octahedral, Tc(III) complex is paramagnetic, with no signals observed in the 1H NMR spectrum. The X-ray crystal structure shows the mutually trans triphenyl-phosphine ligands with the isodiazene and chloride ligands in the equatorial plane. The TcN bond length is 1.738(4) Å while the NN is 1.300(5) Å, which is consistent with the multiple bonding expected for the linearly bonded isodiazene ligand. The TcNN bond angle of 175.6(3)° reflects the sp hybridization of the isodiazene-α-nitrogen atom. The coordination geometry of this complex is a distorted octahedron. Crystal data for C 50H 44Cl 7N 2P 2Tc: monoclinic space group P2 1 n , a = 10.1294(1), b = 26.0792(3), c = 18.8147(3) A ̊ , β = 98.814(1)°, V = 4911.52(11) A ̊ 3 , with D calc = 1.462 g cm. Structure solution based on 6962 unique reflections converged at R = 0.0513 for (1>2 σ(1)); GOF = 1.33.