A suite of late first row transition metal complexes has been synthesized using a monoanionic nitrogen donor β-diketiminate ligand with quinolyl pendant arms, BDIQQH (1). BDIQQNiOTf (2), BDI QQCuCl (4), BDIQQZnCl (5) were prepared from the reaction of 1 with Ni(OTf)2, CuCl2·2H2O and ZnCl2, respectively. BDIQQNiCl (3) was synthesized from an anion exchange of 2 with nBu4NCl. Reaction of 1 and CoI2 afforded the unexpected [(BDIQQ)2Co] +I- (6). Through density functional theory (DFT) calculations, ligand geometries in BDIQQ complexes were investigated and it was found that smaller ionic radius and higher charge destabilize 1:1 metal-ligand complexes relative to alternative 1:2 complexes like 6 owing to significant conformational strain in 1:1 complexes involving metals with small ionic radii. Synthesis and characterization of these complexes, including crystal structures of 4 and 5, are reported, in addition to the results of DFT calculations.
Bibliographical noteFunding Information:
This work was funded by the MHz NMR instrumentation was provided with funds from the NSF (BIR-961477), the University of Minnesota Medical School, and the Minnesota Medical Foundation. We gratefully acknowledge the reviewers for helpful comments that significantly improved the manuscript. National Science Foundation ( CHE-0809575 and 0952054 ). We thank Prof. Valerie Pierre for the use of her fluorescence and UV–Vis spectrophotometers, and we acknowledge Dr. Victor G. Young, Jr. and Lindsay Hinkle for help solving crystal structures. We also thank Dr. Letitia J. Yao for helpful NMR discussions. 800
- Conformation energy