Synthesis and Characterization of Rhenium(III) and Technetium(III) Organohydrazide Chelate Complexes. Reactions of 2-Hydrazinopyridine with Complexes of Rhenium and Technetium

The organohydrazide chelate complexes
MIII(NNpy)(PPh3)2Cl2
(1, 3) (M = Re, Tc) have been synthesized
using
the organohydrazine 2-hydrazinopyridine. The chelated
organohydrazide is a diazenido(1−) ligand that forms
a
five-membered ring with the metal center. An X-ray structural
analysis of 1 indicates that there is a
delocalized
π-system formed by the chelate ring. These octahedral,
d4 metal complexes have diamagnetic 1H NMR
spectra.
Complex 1,
C41.50H34Cl2N3O0.5P2Re,
crystallizes in the triclinic space group P1̄ with
a = 10.5549(7) Å, b =
12.2699(8) Å, c = 16.8206(12) Å, α =
105.9050(10)°, β = 95.8930(10)°, γ =
111.0100(10)°, V = 1906.1(2)
Å3,
Z = 2, and R = 0.0650 based on 5268 unique
reflections. The FABMS+ in (p-nitrobenzyl alcohol) of
3 reveals
a parent ion peak at m/z 799.2. The complex
[Re(HNNpy)(NNpy)(PMe2Ph)2Cl]+[Cl]-
(2) contains a chelated,
neutral organodiazene ligand and a linear, diazenido(1−) ligand.
The X-ray structural analysis of 2,
C26H30Cl2N6P2Re, indicates a
delocalized π-system formed by the chelate ring. The
1H NMR spectrum of 2 is not
paramagnetically shifted. Complex 2 crystallizes in the
orthorhombic space group Pna21 with a
= 17.383(4) Å,
b = 13.967(3) Å, c = 12.002(2) Å,
V = 2913.9(10) Å3, Z = 4,
and R = 0.0384 based on 3083 unique
reflections.