N. Alcock, M. Atkins, B. Golding
1982
Citations
0
Influential Citations
12
Citations
Journal
Journal of The Chemical Society-dalton Transactions
Abstract
The reactions between several alkyl(pyridine)cobaloximes [CoR(Hdmg)2(py)][R = Me, CH2Cl, CHCl2, Et, Pri, Bun, CH2CH2CHCH2, or CH2CHMeCHCH2, (1a)–(1h) respectively; py = pyridine; Hdmg = monoanion of dimethylglyoxime] and trifluoroacetic acid in deuteriochloroform have been monitored by 1H n.m.r. spectroscopy. This technique indicates that addition of trifluoroacetic acid to an alkyl(pyridine)cobaloxime initially causes reversible protonation without loss of pyridine, then a second protonation occurs leading to the loss of pyridine as pyridinium trifluoroacetate. With excess of trifluoroacetic acid, the alkylcobaloximes lose their alkyl group as RH [e.g. propane from (1e)] and slowly deposit a red crystalline solid, identified as the title complex (4) by analysis of its crystal structure. Crystals of (4) are triclinic, space group P, with a= 10.068(3), b= 10.716(5), c= 13.030(3)A, α= 100.15(3), β= 116.76(3), γ= 88.97(3)°, and Z= 2. 1 873 Reflections collected at –80 °C by a four-circle diffractometer were refined to R= 0.053. The Co–O distances are 2.069(2) and 2.057(2)A; and Co–N are 2.126(3), 2.138(2), 2.139(3), and 2.149(3)A.