Three coordinate copper"I# complexes
2376
Raman spectrometer[ The laser power was ca[ IR and Raman spectra
199 mW[ Electronic spectra of complexes were mea!
sured as solids mulled in Nujol using a varian cary!4
double beam spectrophotometer[ The experimental
procedures and instruments used for other measure!
ments are as described previously ð01Ł[
The IR and Raman spectra "Table 1# of free 3!Bzpy
and its copper"I# complexes are similar except the
systematic shifts of the vibration bands related to the
pyridine moiety as expected for N!ligating pyridine
ligands ð19Ł[ The carbonyl stretching vibrations
appear almost at the same positions in complexes as
well as in free 3!Bzpy[ In the far IR region\ 199Ð
399 cm−0\ no bands could be attributable to terminal
nCuÐCl or nCuÐBr\ suggesting bridging halide atoms
whose copperÐhalogen absorption bands are expected
below 199 cm−0 ð10Ł[ For 0]0]0 Cu] bridging halide]
monodentate ligand\ there are several possible struc!
tures including dimer\ cubane\ stepped cubane\ stair
and split stair ð6Ł[
As seen from Table 2\ the n1 vibration mode of the
perchlorate group in Cu"3!Bzpy#1ClO3 is split into
three peaks at 0037\ 0009\ 0937 cm−0 "IR# and 0059\
0938\ 0914 cm−0 "Raman#[ For the n2 mode\ at least
two peaks are observed in the IR spectrum\ but only
one peak in the Raman[ These results are consistent
with a bidentate perchlorate group ð10Ł[ The spectral
results of the nitrate 0]1 complex are consistent with
a bidentate nitrato group ð10Ł[ A distorted tetrahedral
structure is therefore assigned for the monomeric per!
chlorato and nitrato complexes[
X!ray structure analysis of dimeric CuCl"3!benzoyl!
pyridine# complex "0#
Intensity data were collected at 183 K on a MSC:
Rigaku RAXIS IIc imaging plate system\ with a
rotating!anode X!ray source "MoÐKa radiation\
Ä
lꢁ9[60962 A# ð02Ł and corrected for absorption using
the ABSCOR program ð03Ł[ Information concerning
crystallographic data and structure re_nement are
summarized in Table 3[
The structure was solved by Patterson super!
position and Fourier methods[ All non!hydrogen
atoms were subjected to anisotropic re_nement[ The
aromatic hydrogen atoms were generated geo!
Ä
metrically "CÐH _xed at 9[85 A#\ allowed to ride on
their respective carbon atoms and included in struc!
ture!factor calculations with assigned isotropic ther!
mal parameters[
All computations were performed on a DEC Micro
VAX!II computer with the SHELXTL!PLUS system
ð04\ 05Ł[ Analytical expressions of neutral atom scat!
tering factors\ incorporating the real and imaginary
components of anomalous dispersion\ were employed
ð06Ł[ Least!squares re_nement converged to the R
indices and other parameters\ as listed in Table 3[
Selected bond distances and angles are listed in Table
4[ Positional parameters\ anisotropic thermal par!
ameters\ hydrogen atom coordinates\ a full list of
bond lengths and angles and observed and calculated
structure factors have been deposited with the editor
as supplementary material^ copies are available on
request[
The 0]0 azide complex shows a very strong band at
1929 cm−0 "IR# and a weak line at 1969 cm−0 "Raman#
associated with the nas"N2#mode[ In the 0249Ð
0149 cm−0 region\ we would not assign any absorption
band related to the ns"N2#mode due to the absorption
bands of the ligand and\ therefore\ the IR spectra
could not tell us whether the azide group is symmetric
or asymmetric in this complex[ For symmetric azide
groups\ the ns"N2#mode is expected to be IR inactive
but Raman active[ The Raman spectrum of the azide
complex shows
a medium to strong band at
0225 cm−0\ suggesting symmetric azide[ As symmetric
azide groups of the type m!0\2 bridging in the complex
ðCu"Ph2P#1"N2#Ł1 exhibit a nasN2 band at 1942 cm−0
ð11Ł\ we may assign bridging azides of the type m!0\0\2
in this complex since azido ligands of this type usually
absorb around 1939Ð1919 cm−0 ð12\ 13Ł[ For the 0]0
thiocyanato complex\ a single nCN band is observed
above 1099 cm−0\ a result which is suggestive of bridg!
ing thiocyanato groups ð14Ł[ The anionic complex\
ðCu"SCN#1Ł−\ which contains two independent thio!
cyanato groups^ a terminal and a m!N\S\S shows two
nCN bands at 1094 and 1974 cm−0[ The later band is
related to the terminal N!thiocyanate\ whereas the
former is due to the second group ð01Ł[ We may assign
m!N\S\S bridging thiocyanate in the 0]0 complex[ The
results given for the 0]0 cyano complex with such
higher nCN bands compared with those for terminal
cyanides ð1964Ð1984 cm−0[Ł ð15Ł\ or the bridging Ð
CNÐ group ð1099Ð1094 cm−0[Ł ð16Ł\ suggest a struc!
ture similar to that of CuCN=NH2 ð17Ł\ in which the
cyano group acts as a tridentate ligand[
RESULTS AND DISCUSSION
The reaction between copper"I# salts and 3!Bzpy
a}orded the complexes given in Table 0[ 3!Ben!
zoylpyridine\ therefore behaves di}erently from ethyl
isonicotinate which a}ords copper"I# halide com!
plexes of the type CuLnX\ where nꢁ0 and 1\ and
complexes of the type ðCuLnŁX\ where nꢁ1\ 2 and 3
for XꢁNO2 and ClO3 ð07Ł[ All the isolated complexes
are colored and su.ciently stable against air!
oxidation when well!dried[ In acetone and DMF\ the
neutral complexes gave non!conducting solutions\
whereas the nitrate and perchlorate complexes behave
as 0]0 electrolytes ð08Ł with molar conductivities in the
range 014Ð039 V−0 cm−1 mol−0 in acetone[ Thus\ the
last two complexes may be formulated as ðCuL1ŁX\
possessing ionic structures in acetone[
Gohera, Mohamed A. S.
