Ac 300e

The ¹H, ¹³C{¹H}, and bidimensional NMR spectra
were recorded on a Bruker AC 300E, Bruker AV 400, or Bruker AV 600
NMR spectrometer, and chemical shifts were determined by reference
to the residual ¹H and ¹³C{¹H} solvent
peaks.

The ¹H, ¹³C{¹H}, and bidimensional NMR spectra
were recorded on a Bruker AC 300E, Bruker AV 400, or Bruker AV 600
NMR spectrometer, and chemical shifts were determined by reference
to the residual ¹H and ¹³C{¹H} solvent
peaks.

Synthesis-grade solvents were employed
in all cases. Deuterated solvents acetonitrile-d₃ and chloroform-d were purchased from Euriso-top.
The diamine precursor A was obtained, as previously described.^{17 (link)} All other reagents were obtained from commercial
sources. All compounds are >96% pure by elemental analysis. Nuclear
magnetic resonance (NMR) spectra were recorded at 25 °C on a
Bruker AC 300E, Bruker AV 400, or Bruker AV 600 NMR spectrometer.
The corresponding deuterated solvent was used as an internal reference.
The solvents used were acetonitrile and DMSO, and their internal reference
was 1.94 and 2.50 ppm for ¹H spectra, respectively, and
1.32 and 39.52 ppm for ¹³C. Elemental analyses were performed
on a LECO’s CHNS-932 Elemental Analyzer. UV–vis spectroscopy
was carried out on a PerkinElmer Lambda 750 S spectrometer with operating
software. ESI mass (positive mode) analyses were carried out on an
HPLC/MS TOF 6220.