Solution
[EtZn(N(SiMe3)NMe2)]2 has
characterization. In
the
solid
state,
both ortho-metalated DMAP. In the latter case, zincated prod-
uct Zn[(NC5H3-p-NMe2)ZnEt(N(i-Pr)NMe2)]2 was isolated and
structurally characterized. Studies to determine whether these
and analogous zinc hydrazide reagents can metalate pyridine
derivatives other than DMAP are in progress.
a
crystallographically imposed
center of inversion. If the structure is maintained in solution,
the NMe2 groups should give rise to two singlets and the
methylene protons of the ethyl ligands should give rise to a
doublet of quartets. Th◦e 1H NMR spectra recorded at room
temperature and at –70 C, however, revealed only two singlets,
one triplet, and one quartet, indicating a low energy fluxional
process occurs that renders the amine methyl protons and ethyl
methylene protons equivalent. A monomer-dimer equilibrium is
a possible explanation for the dynamic behavior, or the molecule
might adopt a geometry in solution in which the hydrazide
ligand substituents have a syn relationship, resulting in virtual
C2v symmetry and equivalent amine methyl protons and ethyl
methylene protons.
Acknowledgements
Dr James Korp provided technical assistance with the crystal struc-
ture determinations. The Robert A. Welch Foundation (Grant No.
E-1206) provided full support for this research.
References
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Conclusion
The zinc hydrazide complexes [EtZn(N(SiMe3)NMe2)]2 and
[EtZn(N(Me)NMe2)]4, were synthesized from diethyl zinc and
excess of the respective hydrazines, but under similar con-
ditions and using 1-ethyl-2,2-dimethylhydrazine the cluster
Zn3Et4(N(Et)NMe2)2 was obtained. At elevated temperatures,
the cluster Zn3Et4(N(Et)NMe2)2, and at room temperature, the
product of the reaction between ZnEt2 and HN(i-Pr)NMe2,
11444 | Dalton Trans., 2010, 39, 11439–11444
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