The reaction of co-ordinated nitrogen bases with gaseous or liquid hydrogen halides, hx (x = c1, br).
Abstract
When gaseous hydrogen chloride was passed over the
nickel complex, NiC12.PY2 (py = pyridine), there was a small'
but detectable increase in mass. This increase in mass
suggested that the hydrogen halide protonated the co-ordinated
nitrogen on the pyridine ligand thus giving the complex
This thesis describes a systematic study undertaken
to investigate:-
(i) Whether such an increase could be made
quantitative by working under more
favourable conditions namely, using
liquid hydrogen chloride
ii) How general the reaction is by use of other
metal ions and ligands other than pyridine.
During these studies, the bromo complexes were studied
uslng liquid hydrogen bromide. On the other hand, chloro
complexes were studied in liquid hydrogen chloride. The
following complexes were studied
( i) (MX.Py2 = Mn, Fe, Co, ih; X = Cl, Br)
2
.L (L = 1,10 - Phenanthroline, 2,2'
bipyridine and ethylenpdiamine)
Ciii) (M = Cr, Mo; x = Cl, Br)
The results show that liquid hydrogen halicJes,
IIX( = Cl, Br') :react wi-th co-ordinated bases in p y r-i dine,
1,10 - phenanthroline, 2,2' - bipyridine and e t hy Le ne d i ami nc
I
to give halo complexes.NiC12"PY2 and NiBr2.pY2 react as
follows
I,tl i III only one exception namely MoC13· PY3' all t hr: 0 t he rcomplexes
react similarly. The iron complexes, ['e<:12' PY2
and feBr2.pY2 reacted but the products isolated appeared
Tillpuce.
This reaction provides a new route for the synthesis of
h<l lo complexes containing the pyr i d i n ium r o n or' ot hc c pro t o n at c d
nit:rogen base cations. In fact the complexes (Py!l)7Ni13r"
ancl( p yl i ) 3C:rBr6 have been prepared for the first L i IIIC using
this technique.
Another important observation made during t ho p re s c n t
WOrk is the fact that the position of the me t a Lv n i tro ge n
vibrational modes can be uetermined very readily w i t ho ut t ho
need for isotopic substitution. For example the far infrared
spectrum of NiBr2. PY2 shows a peak at 2lfO
complex has been treated with liquid IIBr, 't lio pe.rk JS a bs o n I
-1
CJn HIl!'J1 thc
in tile product, namely (pyH)2NiBr4' The obscllt peAk is the
OJIC due to v(M - N). The technique was used for assi.gnment
of v(M - N) peaks in the other complexes.
In agreement with those of other workers who have clone
so, us ing other techniques" During :the present wor-k , ba nd
assignment for the v(M- N) vibrations have been lIlaJe for the
first time for the complexes CoC12"PY2 and NiBr2"PY2"
Citation
M.Sc.Publisher
University of Nairobi Department of Chemistry, University of Nairobi
Description
Master of Science