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Published on: February 7, 2017
Increasing solubility and stability of linear tricobalt(II) chains with depa (diethyldipyridylamide) ligands
John F Berry1, F Albert Cotton, Tongbu Lu
1Department of Chemistry, PO Box 30012, Texas A&M University, College Station, Texas 77842-3012, USA.
Abstract:
A new and more basic ligand has been used to make two new tricobalt extended metal atom chains (EMACs), namely, Co(3)(depa)(4)Cl(2), 3, and Co(3)(depa)(4)(CN)(2), 4. The depa ligand is di(4-ethyl-2-pyridyl)amide, a useful modification of the well-known di(2-pyridyl)amide, dpa, ligand. The new compounds have been thoroughly characterized, and informative comparisons are made of 3 with Co(3)(dpa)(4)Cl(2), 1, and 4 with Co(3)(dpa)(4)(CN)(2), 2, which were described several years ago. Introduction of the eight ethyl groups into the trimetal compounds improves solubility, makes oxidations easier, and allows for a more complete examination of the magnetic susceptibility as a function of temperature for 3 than was possible for 1. The data clearly indicate that the upper state for 3 has S = (3)/(2) and suggest that this is the case for 1 as well.
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