Frontier ft ir fir spectrometer

Elemental analyses
were carried out using a Thermo Scientific Flash 2000 analyzer. Elemental
content and morphology of the CuLCl complex were characterized by
scanning electron microscopy using a Hitachi SE-SEM 5500 equipped
with an energy-dispersive X-ray analysis system. Infrared (IR) spectra
were obtained using KBr pellets (solid samples) on a PerkinElmer Frontier
FT-IR/FIR spectrometer in a range of 4000–500 cm^–1. Electronic spectra were recorded in methanol on a PerkinElmer Lambda
20 UV–vis spectrophotometer from 200 to 1100 nm. The thermogravimetric
measurement (TGA) was carried out using a TGA Q5000 from TA Instruments,
with an airflow rate of 10 mL min^–1 and a heating
rate of 5 °C min^–1 from 25 to 800 °C.
The EPR spectra of polycrystalline samples at 298 K and solution at
77 K were recorded in quartz tubes with a Joel JES-TE300 spectrometer
equipped with a cylindrical cavity (TE011 mode) operating at the X
band frequency (9.4 GHz) at 100 KHz field modulation.

The Mn²⁺ complexes were prepared in methanol HPLC (100 mL) by combining, in solution, an amount of the manganese(II) nitrate tetrahydrate and the ligand used. In order to prepare the [Mn(ligand)]²⁺, an equimolar solution of manganese(II) nitrate nonahydrate (250 mM) and the ligand (250 mM) were mixed in methanol. Additionally, to prepare the [Mn(ligand)]²⁺ ${\mathrm{C}\mathrm{O}}_3^{2-}$ , an equimolar solution of manganese(II) nitrate nonahydrate (25 mM), ligand (25 mM) and sodium carbonate (25 mM) were mixed in methanol (where the ligand is either pyrazine, quinoxaline or phenazine). The solutions remained at 4 °C until precipitation. Once the complexes formed, the solutions were filtered to collect the product. If solid samples are redissolved and their UV–vis spectrum is obtained, the signals are similar to the UV–vis spectrum calculated for the complexes. The far- and mid-infrared spectra for the different manganese complexes were obtained using an HATR system in a Perkin-Elmer Frontier FTIR/FIR spectrometer in ranges from 700 to 50 and 1400 to 400 cm⁻¹, respectively.

Spectra were recorded on a Frontier FT-IR/FIR spectrometer (Perkin Elmer, Waltham, MA) equipped with a Universal ATR sampling accessory. After measuring the background signal, a 2 μL sample was dried on the crystal using a gentle stream of nitrogen. 64 interferograms were accumulated at a spectral resolution of 2 cm^-1 in the range of 1000–4000 cm^-1 and smoothed using a 2nd order polynomial and a smoothing window of 10 points. For comparison, data were normalized. A second order derivative plot was used to determine absorption maxima. Fibrils were sonicated before recording spectra.