A solution and solid state study of niobium complexes University of ...

Chapter 3
t1/2 =
54
= .
3.7 Synthesis and Spectroscopic Characterisation of Compounds
3.7.1 Chemicals and Instrumentation
(3.25)
All reagents used for the synthesis and characterisation were of analytical grade and
were purchased from Sigma-Aldrich, South Africa, unless otherwise stated.
Reagents were used as received, without further purification. All organic solvents
were purified and dried according to literature. 19
All the infrared spectra of the complexes were recorded on a Bruker Tensor 27
Standard System spectrophotometer with a laser range of 4 000 – 370 cm -1 , coupled
to a computer. All samples were analyzed as solid state species via ATR infrared
spectrophotometry and all data was recorded at room temperature. No solution or
KX (where X = I, Cl, Br) solid salt pellets were utilized since halogen interaction was
expected from the solution cell and the KX pellet preparation technique. All 1 H and
13 C NMR spectra were obtained in CD3OD on a Bruker 300 MHz nuclear magnetic
resonance spectrometer. Chemical shifts are reported relative to tetramethylsilane
using the CD3OD ( 1 H NMR: 3.31 ppm; 13 C NMR: 49.1 ppm ) peak. All 93 Nb NMR
spectra were obtained in CD3OD on a Bruker 600 MHz nuclear magnetic resonance
spectrometer. The applicable resonance frequency was located at 146.93 MHz
Elemental analysis could not be performed on the products obtained due to the
sensitive nature of these crystals.
3.7.2 Synthetic Procedures
The syntheses of all the niobium compounds were performed under Schlenk
conditions due to the air- and moisture sensitive nature of the metal. All product
solutions were stored at -21 °C for possible crysta llization.
19 D. D. Perrin, W. L. F. Armarego, Purification of Laboratory Chemicals, 3 rd Ed., Pergamon Press, 1988.