Metal(II)-promoted hydrolysis of pyridine-2-carbonitrile to pyridine-2-carboxylic acid. The structure of [Cu(pyridine-2-carboxylate)2] · 2H2O

Article abstract of DOI:10.1016/S0277-5387(98)00259-9

Pyridine-2-carbonitrile (2-CNpy) undergoes Cu(II) or Co(II)-promoted hydrolysis to pyridine-2-carboxamide (piaH) and/or pyridine-2-carboxylic acid (pycH). The pathway of pycH formation depends on the presence of 2-amino-2-hydroxymethyl-1,3-propanediol (AL¹) and on the central atom. In the absence of AL¹, Co(II) or Cu(II) ions mediate piaH formation under mild reaction conditions in the first hydrolytic step. Cu(II) ions assist in piaH transformation to pycH by subsequent reflux. In the presence of AL¹ and Co(II), a Co(II) complex containing pyoxaL¹ (2-(2-pyridinyl)-4,4-bis(hydroxymethyl)-2-oxazoline) is formed in the first stage; subsequent decomposition of pyoxaL¹ under the reflux yields pycH. Under similar conditions, no solid Cu(II) complex with pyoxaL¹ can be isolated, but a Cu(II) complex with coordinated pyc^- anions precipitates from the reaction mixture. The synthesis, spectral and magnetic properties of the complexes [Co(H₂O)₂ (piaH)₂]Cl₂, [Co(H₂O)₂(pyc)₂] · 2H₂O, [Cu(H₂O)₂(piaH)₂]Cl₂, [Cu(pyc)₂] and [Cu(pyc)₂] · 2H₂O, including the structure determination of the latter one, are described.

Full text of DOI:10.1016/S0277-5387(98)00259-9

Polyhedron Vol[ 06\ Nos[ 14\ 15\ pp[ 3414Ð3422\ 0887
Þ 0887 Elsevier Science Ltd
\ Pergamon
All rights reserved[ Printed in Great Britain
9166Ð4276:87 ,08[99¦9[99
PII] S9166Ð4276"87#99148Ð8
Metal"II#!promoted hydrolysis of pyridine!1!
carbonitrile to pyridine!1!carboxylic acid[
The structure of ðCu"pyridine!1!
carboxylate# Ł = 1H O
1
1
a
b
a
a
c
³
P[ Segl|a\ꢀ M[ Jamnick yꢁ \ M[ Koman\ J[ Sima and T[ Glowiak
a
Department of Inorganic Chemistry\ Slovak Technical University\ 701 26 Bratislava\ Slovak Republic
b
Department of Ceramics\ Glass and Cements\ Slovak Technical University\ 701 26 Bratislava\ Slovak
Republic
c
Institute of Chemistry\ University of Wroc<aw\ F[ Joliot!Curie 03\ 49 272 Wroc<aw\ Poland
"
Received 2 March 0887^ accepted 13 June 0887#
Abstract*Pyridine!1!carbonitrile "1!CNpy# undergoes Cu"II# or Co"II#!promoted hydrolysis to pyridine!1!
carboxamide "piaH# and:or pyridine!1!carboxylic acid "pycH#[ The pathway of pycH formation depends on
0
the presence of 1!amino!1!hydroxymethyl!0\2!propanediol "AL # and on the central atom[ In the absence of
0
AL \ Co"II# or Cu"II# ions mediate piaH formation under mild reaction conditions in the _rst hydrolytic step[
0
Cu"II# ions assist in piaH transformation to pycH by subsequent re~ux[ In the presence of AL and Co"II#\ a
0
Co"II# complex containing pyoxaL "1!"1!pyridinyl#!3\3!bis"hydroxymethyl#!1!oxazoline# is formed in the _rst
0
stage^ subsequent decomposition of pyoxaL under the re~ux yields pycH[ Under similar conditions\ no solid
0
−
Cu"II# complex with pyoxaL can be isolated\ but a Cu"II# complex with coordinated pyc anions precipitates
from the reaction mixture[ The synthesis\ spectral and magnetic properties of the complexes ðCo"H O#1
1
"
piaH# ŁCl \ ðCo"H O# "pyc# Ł = 1H O\ ðCu"H O# "piaH# ŁCl \ ðCu"pyc# Ł and ðCu"pyc# Ł = 1H O\ including the
1 1 1 1 1 1 1 1 1 1 1 1 1
structure determination of the latter one\ are described[ Þ 0887 Elsevier Science Ltd[ All rights reserved
Keywords] pyridine!1!carbonitrile^ hydrolysis^ copper"II# complexes^ cobalt"II# complexes^ crystal structure[
———————————————————————————————————————————————
INTRODUCTION
withdrawing transition metal ions results in enhanced
electrophilicity of the nitrile carbon\ thus making it
Organic nitriles can coordinate to transition metal
ions via their nitrile group "three bonding modes have
been described so far^ for a review see ð0Ł# or by ano!
ther donor atom of the organic moiety[ In the chem!
istry of pyridinecarbonitriles\ the former mode is
typical for pyridine!1!carbonitrile "further denoted as
−
susceptible to nucleophiles such as OH \ H O\ ROH\
1
and RÐNH ð0\2Ł[
1
As it has previously been observed ð3Ð6Ł\ the reac!
tion of 1!CNpy with some metal"II# salts in aqueous
or alcoholic solutions leads to formation of solid com!
plexes containing pyridine!1!carboxamide "piaH# and
O!alkylpyridine!1!carboximidate "O!Rpii#\ respec!
1
!CNpy# while the latter for pyridine!2!carbonitrile
and pyridine!3!carbonitrile[ It should be pointed out\ tively[ It is worth mentioning that a similar metal"II#
however\ that the coordination of 1!CNpy through promoted hydrolysis of the nitrile group to amide
the pyridine nitrogen cannot be excluded\ at least for was observed in the systems containing 1!carbonitrile!
kinetically inert complexes ð1Ł[
0\09!phenanthroline instead of 1!CNpy ð7Ł for which\
Either mode of 1!CNpy coordination to electron! based on a kinetic analysis\ the authors showed that
its mechanism involved an external attack of a non!
−
coordinated OH ion to the nitrile group of coor!
ꢀ
Author to whom correspondence should be addressed[
dinated ligand[
3
414

3
415
P[ Segl|a et al[
0
2
In the presence of amino alcohols "AL ÐAL in microanalytical methods "Carlo Erba Instruments EA
Scheme 0# and 1!CNpy\ Ni"II# salts yield solid com! 0097# with maximum deviations "in )#] M\ 29[1^ C\
0
plexes containing 1!pyridinyl!1!oxazolines "pyoxaL ! 29[3^ H\ 29[2^ and N\ 29[1[ The water content in
2
pyoxaL # ð8Ł under mild reaction conditions both in hydrates was determined by thermogravimetry[ The
water and alcohols[ However\ Cu"II# and most Co"II# yields of products are related to the metal contents in
complexes containing oxazolines could be prepared reacting mixtures[
only from ethanolic solution[ For example\ solid com!
Magnetic moments were measured with a Gouy
0
plexes ðCoX "pyoxaL # Ł "XꢂCl\ Br or NCS# and balance for the powdered solid at 182 K[ Electronic
1
1
0
ðCuX"pyoxaL # ŁX = 9[4H O "XꢂCl or Br# have been spectra of the powdered samples in nujol mulls and
1
1
0
prepared by the reaction of 1!CNpy with AL in etha! di}use re~ectance spectra in MgO were recorded at
nolic solutions of the corresponding Co"II# and Cu"II# room temperature on a Specord M 39 and a Magna
salts[ Also\ solid complexes containing di}erent 649 spectrophotometer\ respectively[ Magnetic
hydrolytic products of 1!CNpy ð09Ł have been isolated moments\ electronic and IR spectral data of solid
from aqueous solutions[ The complexes were not\ complexes are gathered in Table 0[
however\ characterized in more detail[
Measurements of IR spectra "in solid state and
In this paper the results on the hydrolytic reactions aqueous solution# as well as pH measurements of the
0
of 1!CNpy in the presence or absence of AL in aque! aqueous solutions are described elsewhere ð8Ł[
ous solutions of copper"II# and cobalt"II# salts are
given[ The course of the reactions was monitored by
1
[2[ X!ray structure determination
a solution IR study[ Moreover\ the synthesis and
−
characterization of the solid pyc or piaH!containing
Data collection and cell re_nement were carried out
complexes isolated from the above mentioned aque!
ous solutions are also described[ The X!ray molecular
and crystal structure of one of the products\ ðCu
using KUMA "0880# KM3 di}ractometer software
ð00Ł[ Intensity data were corrected for Lorentz and
polarization e}ects[ The structure was solved by stan!
dard heavy atom procedures with SHELX75 ð01Ł\ and
subsequent Fourier synthesis using SHELXL82 ð02Ł[
Anisotropic thermal parameters were re_ned for all
non!hydrogen atoms[ Geometrical analysis was per!
formed using SHELXL82 ð02Ł[ The structures were
drawn using ORTEP ð03Ł[ The _nal re_ned parameters
are summarized in Table 1[ Selected bond lengths and
angles are collected in Table 2[
"
pyc# Ł = 1H O\ is presented[ The paper summarizes
1 1
results obtained within the study of metal"II#!
facilitated hydrolysis of 1!CNpy and o}ers general
conclusions relating to this _eld[
1
[ EXPERIMENTAL
1
[0[ Chemical rea`ents
Supplementary material including non!hydrogen
3
All the chemicals used were of reagent grade[ Solid and hydrogen atomic coordinates "×09 #\ anisotropic
pyridine!1!carbonitrile "1!CNpy# was puri_ed by dis! displacement parameters for non!hydrogen atoms
1
2
Ä
tillation under reduced pressure[ 1!Amino!1!hyd! "A ×09 # have been deposited at the Cambridge Crys!
0
roxymethyl!0\2!propanediol "AL # was used without tallographic Data Centre[ Observed and calculated
further puri_cation[ Water was double distilled prior structural factors are available from P[ S[
to use[ The other chemicals were used as received[
1
[3[ Preparation of complexes
1
[1[ Analysis and physical measurements
Copper"II# complexes
Copper\ cobalt and nickel were determined by
EDTA titration^ carbon\ hydrogen and nitrogen by
2
ðCu"H O# "piaH# ŁCl "I# and ðCu"pyc# Ł "II#[ 49 cm
1
1
1
1
1
Scheme 0[ Structures and abbreviations of ligands[

Metal"II#!promoted hydrolysis
3416
Table 0[ Magnetic moments\ electronic spectral data\ characteristic IR bands and stereochemistry of solid complexes
containing pyridine!1!carboxamide "piaH# or pyridine!1!carboxylic acid "pycH#
a
a
No[ Complex
m
ef "B[M[#
Electronic spectra \
Infrared spectra
Stereo!
c
maxima of absorption band
chemistry
−0
b
b
"
cm
#
n
a
"CXO#
n
s
"CXO#
I
II
III
IV
ðCu"H
ðCu"pyc#
ðCu"pyc#
1
O#
1
"piaH#
1
ŁCl
1
1
0[89
0[87
0[85
3[89
04099
0552vs
0526s
0533s
0339s
0232s
0237s
0323s
O
S
S
1
Ł
05799br 16999sh
06999br 16999sh
19499
1
Ł = 1H
1
O
ðCo"H
1
O#
1
"piaH#
1
ŁCl
7749
7699
0546vs
O
1
0499
V
ðCo"H
1
O#
1
"pyc#
1
Ł = 1H
1
O
3[68
07799
0511s
0272s
O
0
1
8799
1099
a
vs\ very strong^ s\ strong^ sh\ shoulder^ br\ broad[
For complexes I and IV is XꢂN and for complexes II\ III and V is XꢂO[
b
c
O\ octahedral^ S\ square!planar[
1 1
Table 1[ Crystal data and structure re_nement for ðCu"pyc# Ł = 1H O "complex III#
Crystal data
Empirical formula
Formula weight
Crystal size "mm#
Crystal system
Space group
01 1 5
C H01CuN O
232[67
9[49×9[29×9[19
triclinic
P0¹
Z
0
Ä
Ä
Ä
Unit cell dimensions
aꢂ4[061"0# A\ aꢂ63[81"2#>
bꢂ6[543"1# A\ bꢂ73[11"2#>
cꢂ8[064"1# A\ gꢂ60[58"2#>
221[8"0#
0[604
064
Ä
2
Volume "A #
Density "calc[# "Mg m
F"999#
−2
#
−0
Linear absorption coe.cient "m# "mm
#
1[511
Data collection
Di}ractometer
Radiation type
KUMA KM 3
Cu Ka lꢂ0[43079 A
Ä
Temperature "K#
182"1#
U range for data collection ">#
Index ranges
3[88Ð70[23
h −5Ð2\ k −8Ð8\ l −00Ð00
Number of data collected
Independent re~ections
Absorption correction
1397
0251 "Rintꢂ9[9414#
no
Solution and re_nement
Re_nement method
full!matrix\ least!squares on F
Data:restraints:parameters
Goodness!of!_t on F
0296:9:87
9[786
1
Final R indices "I×1s"I##
R indices "all data#
R
R
0
ꢂ9[9318\ wR
ꢂ9[9377\ wR
1
ꢂ9[0900
ꢂ9[0168
0
1
Extinction coe.cient
Largest di}[ peak and hole "e A
9[908"3#
9[809:−9[564
Ä
−2
#
of an aqueous solution of copper"II# chloride dihy! I started to crystallize from the reaction solution after
drate "09 mmol# was mixed with 1!CNpy "19 or several hours[ The crystals were _ltered o}\ washed
3
9 mmol#[ The resulting solution was left to slowly with ethanol and _nally dried in vacuo "yield 79)#[
evaporate at room temperature[ Pale blue crystals of Complex II was deposited as a blue solid when the

3
417
P[ Segl|a et al[
Ä
Table 2[ Selected bond lengths "A# and angles "># for ðCu"pyc#
1 1
Ł = 1H O "complex
III#
CuÐO"0#
O"0#ÐC"5#
NÐC"0#
C"0#ÐC"1#
C"1#ÐC"2#
C"3#ÐC"4#
0[830"1#
0[178"1#
0[232"2#
0[272"2#
0[283"2#
0[278"3#
CuÐN
O"1#ÐC"5#
NÐC"4#
C"0#ÐC"5#
C"2#ÐC"3#
0[868"1#
0[128"2#
0[239"2#
0[409"1#
0[263"3#
O"0#ÐCuÐN
C"5#ÐO"0#ÐCu
C"0#ÐNÐCu
NÐC"0#ÐC"1#
C"1#ÐC"0#ÐC"5#
C"3#ÐC"2#ÐC"1#
NÐC"4#ÐC"3#
O"1#ÐC"5#ÐC"0#
71[8"0#
004[8"0#
001[1"0#
011[2"1#
012[0"1#
008[2"1#
019[8"1#
008[7"1#
O"0#(0ÐCuÐN
C"0#ÐNÐC"4#
C"4#ÐNÐCu
86[0"0#
008[5"1#
017[0"1#
003[5"1#
007[0"1#
008[6"1#
015[2"1#
002[8"1#
NÐC"0#ÐC"5#
C"0#ÐC"1#ÐC"2#
C"2#ÐC"3#ÐC"4#
O"1#ÐC"5#ÐO"0#
O"0#ÐC"5#ÐC"0#
Symmetry transformations used to generate equivalent atoms] (0 −x\ −y\
z[
−
above reaction mixture was re~uxed for up to 19 h[ "complex I#\ complex IV did not convert to the pyc!
The crystals were separated from the cool solution by ligand containing complex even after 19 h re~ux of
_
ltration\ washed with ethanol and dried in vacuo the above reaction mixture\ i[e[ pure complex IV was
"yield 84)#[
isolated again as the only product in 64) yield[ Com!
In addition to the above method\ the complex pound IV was also prepared directly from CoCl and
1
ðCu"H O# "piaH# ŁCl was prepared directly from piaH ð04\ 05Ł with no piaH hydrolysis observed[
1
1
1
1
piaH and CuCl ð04Ł[ No hydrolysis of piaH to pycH
was also observed[
The complex ðCo"H O# "pyc# Ł = 1H O "V# was for!
1 1 1 1
2
1
med by 29 h re~ux of a 49 cm aqueous solution of 1!
0
ðCu"pyc# Ł = 1H O "III#[ Method A[ 19 mmol of 1! CNpy "19 mmol#\ AL "19 mmol# and CoCl1
1
1
0
2
amino!0\2!propanediol "AL # was dissolved in 49 cm
"09 mmol#[ Orange crystals of V were _ltered o} and
of an aqueous solution of CuCl "09 mmol#[ 1!CNpy washed with ethanol "yield 79)#[ Complex V can also
1
"
19 mmol# was then added to the system and the result! be synthesized by 29 h re~ux of 09 mmol ðCoCl1
0
ing solution was left to slowly evaporate at room "pyoxaL # Ł ð09Ł in water in a similar way as complex
1
temperature[ A mixture of solid complexes containing III in about 74) yield[
−
piaH or pyc ligands was deposited after several days[
Upon adjusting pH of the above resulting solution to
2
[ RESULTS AND DISCUSSION
2
[4\ complex I was precipitated within 04 min[ When
0
an aqueous solution of 1!CNpy\ AL and CuCl was
1
2
[0[ Stereochemistry of solid complexes
re~uxed for 21 h and then cooled down\ the only com!
pound\ formed in 84) yield\ was pure blue violet solid
complex III[ A well!shaped crystal of III was used for
structure determination[
The values of magnetic moments\ electronic and IR
spectral data for the studied complexes are listed in
Table 0[ The spectral and magnetic properties of com!
plexes ðM"H O# "piaH# ŁCl "I and IV# are identical
to those prepared directly from piaH ð04\ 05Ł and
consistent with their monomeric\ hexacoordinated
structure with two N\O!chelating piaH ligands and
two water molecules present in the primary coor!
dination sphere[ The mode of piaH coordination has
been proved by a single!crystal X!ray analysis of com!
plex I ð06Ł[
2
Method B[ An aqueous solution "49 cm # of
0
1
1
1
1
0
9 mmol of ðCuCl"pyoxaL # ŁCl = 9[4H O ð09Ł was left
1
1
to slowly evaporate at room temperature[ From the
concentrated solution\ complex III deposited upon
several days standing "yield 84)#[
Cobalt"II# complexes
ðCo"H O# "piaH# ŁCl
"IV#
and
ðCo"H O#1
The IR spectra of complex III show broad bands
1
1
1
1
1
2
−0
"
pyc# Ł = 1H O "V#[ When 49 cm of an aqueous solu! located in the region from 2099 to 2599 cm attribu!
1 1
tion of cobalt"II# chloride hexahydrate "09 mmol# was table to the water molecules[ Both copper"II# com!
mixed with 1!CNpy "19 or 39 mmol#\ orange complex plexes II and III exhibit "Table 0# a band of the
−
−0
IV started to crystallize after several days[ The crystals asymmetric stretch n "COO # at 0526 and 0533 cm
a
were _ltered o}\ washed with ethanol and _nally dried together with a band of the symmetric stretch
−
−0
in vacuo "yield 79)#[ Contrary to its Cu"II# analogue n "COO # at 0232 and 0237 cm \ respectively[ The
s

Metal"II#!promoted hydrolysis
3418
−
−
di}erence n "COO #−n "COO #\ being 183 and molecule\ as a whole\ is nearly planar[ The Cu"II#
1
a
s
−
0
85 cm for complexes II and III\ respectively\ can atom has centrosymmetric square!planar coor!
be taken as a proof of unidentate coordination of the dination with trans positioned oxygen and nitrogen
−
carboxylato group to the central atom ð07Ł[ The IR donor atoms of two N\O!chelating pyc ligands[ The
spectra of all complexes IÐV provide an evidence of interatomic distances CuÐO"0# and CuÐN are 0[830"1#
Ä
organic ligands coordination through the 1!pyridinyl and 0[868"1# A\ respectively\ and are consistent with
ring nitrogen ð08Ł[ the values reported for other copper"II# complexes
In general\ room temperature magnetic measure! ð16Ł[ The packing of Cu"pyc# moieties in the crystal
1
ments and spectral data do not provide su.cient structure is shown in Fig[ 0[ The molecules Cu"pyc#1
information for a de_nite determination of the ster! form parallel planes[ There are weak interactions
eochemistry of Cu"II# complexes ð19Ł and this relates between copper atoms of one plane and O"1# atoms
Ä
also to complexes II and III previously prepared from of neighboring planes "Cu = = = O"1aa#ꢂ1[703"3# A#[
pycH ð10\ 11\ 12Ł[ To eliminate the question on ster! The molecules of water are not coordinated to the
−
eochemistry of II and III\ an X!ray single!crystal central atom\ they are bonded to O"1# atoms of pyc
analysis of complex III "the one with better evolved ligands by hydrogen bonds "O"1# = = = H"1#ꢂ
Ä
crystals# was performed[
0[843"4# A^ O"2#ÐH"1# = = = O"1#ꢂ061[0"5#>#[
The spectral and magnetic properties of ðCo
The similarity of the IR spectra for II and III "Table
"
pyc# "H O# Ł = 1H O "V# are identical to those given 0# led us to the conclusion of the square planar coor!
1 1 1 1
in ð13Ł for a compound of the same composition syn! dination of the central Cu"II# atom just like in II[
thesized directly with pycH[ Moreover\ the X!ray crys!
tal study of V ð14\ 15Ł has revealed that the primary
coordination sphere of this monomeric octahedral
2
[2[ IR spectra of aqueous solutions
complex consists of two anions of pyridine!1!car!
boxylic acid "as N\O!coordinated chelates# and two
molecules of water[
Owing to the known characteristic IR spectral fea!
tures of 1!CNpy and the products of its trans!
formation\ the course of the reactions occurring in the
investigated systems at various conditions can cosily
be followed[ The assignment of solid state and solu!
2
[1[ Crystal structure description of complex III
The crystal structure of ðCu"pyc# Ł = 1H O "III# con! tion IR spectral bands in Fig[ 1 to free and coordinated
1
1
sists of discrete Cu"pyc# molecules and water mol! ligands is supported by the literature and our previous
1
ecules occupying lattice sites "Fig[ 0#[ The Cu"pyc#1 data ð8\09\07Ł[
1 1 1 1
Fig[ 0[ Packing of Cu"pyc# and H O in the crystal structure of ðCu"pyc# Ł = 1H O "complex III#[

3
429
P[ Segl|a et al[
Fig[ 1[ IR spectra of aqueous solutions[ Numbers in the _gure represent spectrum numbers in Table 3[ For assignment and
denotation of vibrations see Table 0 and our papers ð8\ 09Ł[

Metal"II#!promoted hydrolysis
3420
0
A kinetic study of the reaction of 1!CNpy with AL
very low in comparison with that observed in the
in aqueous solutions of Ni"II# by means of electronic metal"II# salts containing systems[
spectroscopy has been presented partly in ð17Ł[ Some
Formation of the Co"II# complexes was indicated
new mechanistic information of this reaction was by signi_cant spectral changes "Fig[ 1"B##[ Moreover\
obtained from a solution IR study ð8Ł[ The IR spectra the IR spectrum of none of the systems related to Fig[
0
of pyoxaL and its solid complexes of Ni"II#\ Co"II# 1"B# exhibits the strong band due to n"C2N# of 1!
−
0
and Cu"II# have been published\ too ð8\ 09Ł[
CNpy at 1135 cm [ At the same time\ the pH values
In this paper the results on the hydrolytic reactions of the measured solutions depend strongly on the reac!
0
of 1!CNpy in the presence or absence of AL in aque! tion time "see Table 3#[ In agreement with these spec!
ous solutions of copper"II# and cobalt"II# salts are tral and pH changes we have concluded that a
given[ Changes in solution IR spectra in the region nucleophilic reaction on 1!CNpy takes place at room
−
0
0
from 0949 to 0599 cm are for some of the studied temperature yielding a Co"II# complex with pyoxaL
systems illustrated in Fig[ 1[ The curves 0\ 2\ 4\ 5\ and "spectrum 5 has not changed during several days#[
Ð02 represent the spectra of solutions prepared at This conclusion is also con_rmed by a comparison of
7
0
room temperature\ thick solid curves 1\ 3 and 6 were the uncoordinated pyoxaL spectrum "curve 0# with
obtained after several!hours re~ux of the solutions[ those of the Co"II# solutions containing pyoxaL
0
The composition of the starting solutions\ the time "spectra 4 and 5#[ However\ in the presence of Co"II#\
0
and temperature used in preparing the measured solu! pyoxaL gradually hydrolyses when being re~uxed for
tions\ as well as the dominant components observed 29 h leading thus to the solution containing mainly
0
0
in the IR spectra are given in Table 3[
The spectra of pyoxaL itself and its decomposition
pycH\ AL and its cationic form AL H "spectrum 6#[
Unlike the solutions containing Co"II# ions\ the
0
products in aqueous solution are illustrated in Fig[ presence of Cu"II# gives rise to di}erent spectral chan!
0
1
"A# ð8Ł[ Uncoordinated pyoxaL "curve 0# is quite ges "Fig[ 1"C##[ Stemming from the IR spectra evol!
stable at room temperature for a long time[ Under ution we have concluded that a nucleophilic reaction
re~ux it undergoes\ however\ a gradual hydrolysis to on the nitrile group proceeds in such solutions at room
0
0
pycH\ AL and its protonated form AL H "spectrum temperature "spectrum 7# and Cu"II# complexes with
0
−
1
#[ Curve 2 represents a solution IR spectrum of unco! both pyoxaL and pyc ligands are formed[ Sim!
ordinated pycH\ curve 3 relates to a aqueous solution ultaneously\ however\ decomposition of pyoxaL to
of the 0]0 molar mixture of pycH and AL [
The room temperature IR spectra of aqueous solu! plexes with pyc ligand become dominant species in
tions of 1!CNpy and AL in the absence of metal"II# solutions "spectrum 09#[ Moreover\ bands at
salts ð8Ł showed that the rate of pyoxaL formation is 0334 cm in spectra 8 and 09 are assigned to the
0
0
−
pyc proceeds "spectrum 8# and after 13 h Cu"II# com!
−
0
0
−0
Table 3[ Composition of aqueous solution
c
Spectrum
No[
Reaction
temperature
Reaction
time
Dominant species
a
b
Starting solution
pH
0
0
0
1
2
3
4
5
6
7
8
pyoxaL
pyoxaL
pycH
r[t[
re~ux
r[t[
re~ux
r[t[
r[t[
re~ux
r[t[
r[t[
r[t[
r[t[
4 min
49 h
4 min
49 h
4 min
019 min
29 h
4 min
019 min
13 h
6[9
5[7
6Ð09
5[7
7[2
8[2
5[7
5[8
6[7
7[2
6[3
pyoxaL
0
0
0
pyc\ AL \ AL H
pyc
0
0
0
pyc¦AL
1!CNpy¦AL ¦CoCl
1!CNpy¦AL ¦CoCl
1!CNpy¦AL ¦CoCl
1!CNpy¦AL ¦CuCl
1!CNpy¦AL ¦CuCl
1!CNpy¦AL ¦CuCl
ðCuCl"pyoxaL #
Cl = 9[4H
ðCuCl"pyoxaL #
Cl = 9[4H
ðCuCl"pyoxaL #
Cl = 9[4H
pyc\ AL \ AL H
0
0
0
1
1
1
1
1
1
complex of pyoxaL
complex of pyoxaL
AL \ AL H\ complex of pyc
complex of pyoxaL and pyc
complex of pyoxaL \ pyc and pia
0
0
0
0
0
0
0
0
0
0
0
0
9
0
complex of pyc\ pia and pyoxaL
complex of pyoxaL
0
0
1
1
1
Ł!
Ł!
Ł!
4 min
1
O
0
0
0
0
1
2
r[t[
r[t[
019 min
37 h
6[0
4[5
complex of pyoxaL
1
O
0
0
complex of pyc and pyoxaL
1
O
a
1
Solutions 0Ð09] the concentrations of organic compounds and MCl were 9[49 and 9[14 M\ respectively^ solutions 00Ð02]
0
the concentration of complex ðCuCl"pyoxaL #
1 1
ŁCl = 9[4H O was 9[14 M[
b
r[t[ꢂroom temperature[
Species observed in IR spectra[
c

3
421
P[ Segl|a et al[
0
symmetric valence vibration of the CNO group of Ni"II# complexes with pyoxaL are formed both in
pyridine!1!carboxamide "Table 0# which has appeared water "reaction 7# and ethanol ð8Ł regardless the coun!
0
0
in the solution\ too[ PyoxaL is present in solution ter anions[ Halide complexes of Co"II# with pyoxaL
after 13 h only in a small amount[ are formed only in ethanol "reaction 0# while pyoxaL
0
Curve 00 in Fig[ 1"D# represents the IR spectrum of formation in water "reaction 7# was observed when
0
an aqueous solution of ðCuCl"pyoxaL # ŁCl = 9[4H O starting with Co"ClO # or Co"NCS#1 ð09Ł[ Solid
1
1
3 1
0
ð09Ł[ The spectral changes "curves 01 and 02# con_rm Cu"II#ÐpyoxaL complexes ð09Ł can be synthesized
a gradual room temperature hydrolysis of the coor! only in ethanolic solution "reaction 0#[ Some of these
dinated pyoxaL directly to pyc [ Contrary to the reactions can take place also in the presence of other
0
−
1
2
solutions which are represented by spectra 8 and 09\ amino alcohols "denoted in Scheme 0 as AL and AL #
no formation of piaH was observed in the solutions but the present paper is focused mainly to the in~uence
0
0
1 and 02[
of AL on addition reaction products of 1!CNpy[
However\ in this paper the results on the hydrolytic
0
reactions of 1!CNpy in the presence or absence of AL
in aqueous solutions of copper"II# and cobalt"II# salts
are described in detail[
2
[3[ Reactions of pyridine!1!carbonitrile and formation
of pyridine!1!carboxylic acid
0
The reactions of 1!CNpy and pyoxaL in aqueous
solutions of Co"II# and Cu"II# salts under our exper!
imental conditions are outlined in Scheme 1 "see also
Section 1\ Fig[ 1 and Table 3#[ Moreover\ the solid
3[ CONCLUSIONS
0
complexes of Co"II# and Cu"II# containing pyoxaL
The main conclusions of this paper can be sum!
marized as follows[
have been prepared by the reaction of 1!CNpy with
0
AL ð09Ł[ For the sake of mutual comparability\ Ni"II#
complexes are included in Scheme 1\ too[
0[ The reaction of 1!CNpy with water or hydroxide
ion in aqueous solution of metal"II# salts leads to
the solid complexes containing piaH "reaction 2#[
The hydrolysis of piaH to pycH "reaction 3# was
0
All three transition metals M"II# mediate a pyoxaL
0
formation from 1!CNpy and AL [ The process is\
however\ solvent and starting salt dependent[ Solid
Scheme 1[ Formation of Cu"II#\ Ni"II# and Co"II# complexes containing di}erent reaction products of pyridine!1!carbonitrile
1!CNpy#[
"

Metal"II#!promoted hydrolysis
3422
observed only in re~uxed solutions containing
Cu"II#[
[ The reaction of 1!CNpy with AL in aqueous solu!
Borisov\ Y[ A[\ Struchkov\ Y[ T[\ Batasanov\ A[
S[ and Belikov\ V[ M[\ Inor`[ Chem[\ 0877\ 16\
3935[
0
1
3
4
5
[ Segl|a\ P[ and Jamnick yꢁ \ M[\ Inor`[ Chim[ Acta\
tion of Cu"II# salts at room temperature "reaction
0
877\ 035\ 82[
4
# leads to the fast formation of Cu"II# complexes
[ Jamnick yꢁ \ M[\ Segl|a\ P[ and Koman\ M[\ Poly!
hedron\ 0884\ 03\ 0726[
0
containing pyoxaL [ These complexes behave as
intermediates and undergo a gradual decompo!
sition to pyridine!1!carboxylic acid "reaction 5#
already at room temperature[ Simultaneously the
nucleophilic attack of water or hydroxide on the
nitrile group of coordinated 1!CNpy leads to the
formation of copper complex with pyridine!1!car!
boxamide which is fully stable at room temperature
in solution[ This sequence of reaction steps is sup!
ported by a kinetic analysis of analogous systems
[ Barnard\ P[ F[ B[\ J[ Chem[ Soc[ A\ 0858\ 1039[
6[ Byers\ P[\ Drew\ M[ G[ B[\ Hudson\ M[ J[\ Isaacs\
N[ S[\ Upadhaya\ A[ and Madic\ Ch[\ Polyhedron\
0
883\ 02\ 234[
7
8
[ Breslow\ R[\ Fairweather\ R[ and Keana\ J[\ J[
Am[ Chem[ Soc[\ 0856\ 78\ 1024[
[ Segl|a\ P[ and Jamnick yꢁ \ M[\ Inor`[ Chim[ Acta\
0
882\ 194\ 110[
0
9[ Segl|a\ P[\ Jamnick yꢁ \ M[\ Koman\ M[ and Glow!
iak\ T[\ Polyhedron\ 0887\ 06\ 1654[
containing
1!carbonitrile!0\09!phenanthroline 00[ Kuma\ 0880[ Kuma KM3 User|s Guide\ Version
instead of 1!CNpy\ described in ð7Ł[ From that
2[0[ Kuma Di}raction\ Wroc<aw[
solution a mixture of solid complexes containing 01[ Sheldrick\ G[ M[\ SHELXS!75[ Crystallo`raphic
−
Computin`\ Vol[ 2[ Oxford University Press\ 0874\
pp[ 064Ð078[
piaH or pyc ligands deposited after several days
see Section 1#[ When an aqueous reaction mixture
"
0
02[ Sheldrick\ G[ M[\ SHELXL!82[ Pro`ram for
Re_nement of Crystal Structure[ University of
G oà ttingen\ Germany\ 0883[
of 1!CNpy\ AL and CuCl is re~uxed for a long
1
time\ well!shaped crystals of product III appeared
"reaction 6#[
0
3[ Johnson\ C[ K[\ ORTEP[ Report ORNL Ð 2683[
Oak Ridge National Laboratory\ TN\ 0854[
pyoxaL # Ł "reaction 8# a gradual hydrolysis of the 04[ Sekizaki\ M[ and Yamasaki\ K[\ Spectrochim[
2
[ Upon a re~ux of aqueous solutions of ðCoCl1
0
"
1
0
0
pyoxaL ligand to pycH and AL is observed and
Acta\ 0858\ 14A\ 364[
complex ðCo"H O# "pyc# Ł = 1H O is isolated[ That 05[ Sekizaki\ M[\ Tanase\ M[ and Yamasaki\ K[\ Bull[
1
1
1
1
Chem[ Soc[ Jpn[\ 0858\ 31\ 288[
complex can also be prepared by re~uxing an aque!
0
06[ Brown\ D[ H[\ MacSween\ D[ R[\ Mercer\ M[ and
Sharp\ D[ W[ A[\ J[ Chem[ Soc[ A\ 0860\ 0463[
ous solution of 1!CNpy\ AL and CoCl for up
1
2
9 h[
0
7[ Nakamoto\ K[\ Infrared and Raman Spectra of
Inor`anic and Coordination Componds[ Wiley\
New York\ 0875\ p[ 121[
3
4
[ The pure ðCu"pyc# Ł = 1H O was also prepared
1
1
at room temperature directly from ðCuCl
0
"
pyoxaL # ŁCl = 9[4H O ð8Ł via its decomposition in 08[ Rao\ C[ N[ R[\ Chemical Applications of Infrared
1
1
water "reaction 1#[
[ Now the crystal and molecular structure of com!
Spectroscopy[ Academic Press\ New York\ 0852\
p[ 206[
1
1
1
1
1
1
1
9[ Lever\ A[ B[ P[\ Inor`anic Electronic Spectroscopy\
1nd edn[ Elsevier\ Amsterdam\ 0873\ p[ 448[
0[ Kleinstein\ A[ and Webb\ G[ A[\ J[ Inor`[ Nucl[
Chem[\ 0860\ 22\ 394[
1[ Gillard\ R[ D[ and Laurie\ S[ H[\ J[ Chem[ Soc[
A\ 0857\ 1477[
2[ D|Ascenzo\ G[ and Wendlandt\ W[ W[\ Anal[
Chim[ Acta\ 0869\ 49\ 68[
3[ Ellis\ V[ M[\ Vagg\ R[ S[ and Watton\ E[ C[\ J[
Inor`[ Nucl[ Chem[\ 0863\ 25\ 0920[
4[ Chang\ S[ C[\ Ma\ J[ K[ H[\ Wang\ J[ T[ and Li\
N[ C[\ J[ Coord[ Chem[\ 0861\ 1\ 20[
5[ Lumme\ P[\ Viertola\ M[ and Lundgren\ G[\
Suom[ Kemistil[ B\ 0858\ 31\ 169[
plex III fully con_rms the conversion of the 1!
CNpy to the coordinated pyc anions in aqueous
−
solutions of CuCl [ This complex is square!planar
1
−
with two N\O!coordinated pyc ligands and two
uncoordinated molecules of water[ The same
arrangement of donor atoms bonded to the central
atom Cu"II# is supposed for complex II[
REFERENCES
0
1
2
[ Michelin\ R[ A[\ Mozzon\ M[ and Bertani\ R[\
Coord[ Chem[ Rev[\ 0885\ 036\ 188[
[ Walton\ R[ A[\ J[ Inor`[ Nucl[ Chem[\ 0855\ 17\
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Holloway\ C[ E[\ J[ Coord[ Chem[\ 0886\ 30\ 24[
17[ Segl|a\ P[\ Elias\ H[ and Geiser\ C[\ Proc[ 01th
Conf[ Coord[ Chem[\ Smolenice Ð Bratislava\
0878\ p[ 204[
1
118[
[ Belokon\ Y[ N[\ Tararov\ V[ I[\ Savel|eva\ T[ F[\
Vitt\ S[ V[\ Paskonova\ E[ A[\ Dotdyaev\ S[ Ch[\