(98%), cobalt(II) acetate tetrahydrate
(99%), copper(II) dichloride dihydrate (99%), manganese(II) acetate
tetrahydrate (99%), iron(II) chloride tetrahydrate (99%), and 2-mercaptopyridine N-oxide sodium salt (96%) were all purchased from Sigma-Aldrich
and used as received.
Acetonitrile (CH3CN; Fulltime
Chemical, HPLC/Spectro
grade, >99%) was dried with 4 Å molecular sieves (Alfa Aesar)
before usage. Tetrabutylammonium hexafluorophosphate (NBu4PF6; Tokyo Chemical Industry Co., Ltd.,
>98.0%) and glacial acetic acid (CH3COOH; Merck, 100%)
were used as received.
Electrospray ionization (ESI) mass spectrometry
was done using
a Finnigan MAT LCQ spectrometer while high-resolution mass spectroscopy
(HRMS) was done using a Bruker micrOTOF-QII spectrometer. Elemental
analyses (EAL) of carbon, hydrogen, nitrogen, and nickel were done
using an ElemenVario Micro Cube. NMR spectra were performed on Bruker
AV III 400HD (BBFO probe) spectrometer. 1H NMR spectra
chemical shifts were reported in δ ppm relative to DMSO-d6 (δ = 2.05 ppm). Multiplicities were
recorded as: d (doublet) and t (triplet) respectively. The number
of protons (n) for a given resonance was indicated
by nH while coupling constants were reported as J value in Hertz (Hz).