Steric effects on the electronic and molecular structures of nickel(II) and cobalt(II) 2,6-dipyrazol-1-ylpyridine complexes |
| |
| Institution: | 1. Institute of Nuclear and Radiological Sciences and Technology, Energy and Safety, National Centre for Scientific Research “Demokritos”, 15310 Athens, Greece;2. Institute of Biosciences & Applications, National Centre for Scientific Research “Demokritos”, 15310 Athens, Greece;3. Institute of Nanoscience and Nanotechnology, Department of Materials Science, National Centre for Scientific Research “Demokritos”, 15310 Athens, Greece |
| |
| Abstract: | The complexes M(L1R)2](BF4)2 (M=Ni, Co; L1R=2,6-dipyrazol-1-ylpyridine L1H], 2,6-bis-{3-iso-propylpyrazol-1-yl}pyridine L1Pri], 2,6-bis-{3-phenylpyrazol-1-yl}pyridine L1Ph], 2,6-bis-{3-2,4,6-trimethylphenyl]pyrazol-1-yl}pyridine L1Mes]) and M(L2)2](BF4)2 (M=Ni, Co; L2=2-{3-2,4,6-trimethylphenyl]pyrazol-1-yl}-6-{5-2,4,6-trimethylphenyl]pyrazol-1-yl}pyridine) have been prepared. Single crystal structure determinations of M(L1H)2](BF4)2 (M=Ni, Co) and solvates of Ni(L1Mes)2](BF4)2, Co(L1Mes)2](ClO4)2 and Co(L2)2](BF4)2 all show six-coordinate metal centres with local near-D2d symmetry. The L1Mes and L2 mesityl substituents have only a small effect on the MN{pyrazole} (M=Ni, Co) bond lengths in these compounds. The d–d spectra of the complexes show that L1Mes is a significantly better donor ligand than L1H, L1Pri or L1Ph, and that L1Pri is a weaker ligand than might be expected purely on inductive grounds. A combination of UV–Vis/NIR, EPR, NMR and magnetic measurements have demonstrated that all the Co(II) compounds are high-spin in the solid state and in solution at 290 K. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
