Synthesis, spectral and electrochemical characteristics of asymmetrical iron(II) tris-dioximates

Article abstract of DOI:10.1016/S0277-5387(98)00168-5

Meridianal- and axial-asymmetrical clathrochelate tris-dioximates of the FeD₂D′(BF)₂ and FeD₃(BX)(Y) types (where D,D′=dioximes dianions, X=C₆H₅, F; Y=BF, Bn-C₄H₉, SnCl₃) have been prepared by a stepwise synthesis from a planar-square macrocyclic precursors in the first case and from a semiclathrochelate compounds immobilized on the sorbent surface in the second one. The composition and structure of the isolated compounds have been established from elemental analysis data, polynuclear NMR, 57 Fe Moessbauer and FAB mass spectra. The structure parameters of α-benzyldioximate FeBd₃(BF)(Bn-C₄H₉) · C₆H₅CH₃ · ¹₂-C₈H₁₆ (Fe-N distance - 1.89 A, bite angle - 38.6°, polyhedron distortion angle - 17.9°) were determined by X-ray crystallography. The electrochemical properties of the obtained complexes and their dependence on the nature of a ligand have been determined by cyclic voltammetry.

Full text of DOI:10.1016/S0277-5387(98)00168-5

Polyhedron Vol[ 06\ Nos[ 14\ 15\ pp[ 3204Ð3215\ 0887
Þ 0887 Elsevier Science Ltd
Pergamon
All rights reserved[ Printed in Great Britain
9166Ð4276:87 ,08[99¦9[99
\
PII] S9166Ð4276"87#99057Ð4
Synthesis\ spectral and electrochemical
characteristics of asymmetrical iron"II# tris!
dioximates
Yan Z[ Voloshin\ꢀa Oleg A[ Varzatskii\b Aleksei V[ Palchik\b
Ernest V[ Polshin\b Yurii A[ Maletinb and Nataly G[ Strizhakovab
aKarpov Institute of Physical Chemistry\ Moscow 092953\ Russia
bInstitute of General and Inorganic Chemistry\ Kiev 141031\ Ukraine
"Received 00 November 0886^ accepted 10 April 0887#
Abstract*Meridianal! and axial!asymmetrical clathrochelate tris!dioximates of the FeD1D?"BF#1 and
FeD2"BX#"Y# types "where D\D?ꢁdioximes dianions\ XꢁC5H4\ F^ YꢁBF\ Bn!C3H8\ SnCl2# have been pre!
pared by a stepwise synthesis from a planar!square macrocyclic precursors in the _rst case and from a
semiclathrochelate compounds immobilized on the sorbent surface in the second one[ The composition and
structure of the isolated compounds have been established from elemental analysis data\ polynuclear NMR\
46Fe Mossbauer and FAB mass spectra[ The structure parameters of a!benzyldioximate FeBd "BF#"Bn!
Ã
2
0
1
Ä
C3H8# = C5H4CH2 =ÐC7H05 "FeÐN distance Ð 0[78 A\ bite angle Ð 27[5>\ polyhedron distortion angle Ð 06[8># were
determined by X!ray crystallography[ The electrochemical properties of the obtained complexes and their
dependence on the nature of a ligand have been determined by cyclic voltammetry[ Þ 0887 Elsevier Science
Ltd[ All rights reserved
Keywords] cage compounds^ 46Fe Mossbauer spectra^ electrochemistry^ X!ray structure[
Ã
———————————————————————————————————————————————
INTRODUCTION
symmetrical clathrochelate[ Similarly\ in the second
case\ when the capping agents display an essentially
di}erent activity\ a second intermediate\ being of a
semiclathrochelate nature\ will preferably be formed
by the strongest of them and will be presumably
capped at a statistic ratio\ since the second capping is
not a rate!controlling step ð7Ð01Ł[ Additionally\ a
higher crystal lattice energy for symmetrical com!
pounds as compared to that for asymmetrical ones is
observed] in most cases clathrochelates are obtained
in a solid state in the course of reaction and\ therefore\
an increase in the crystal lattice energy leads to a
shift in equilibrium in the direction of the symmetrical
product formation[ When asymmetrical dioximes
such as phenylglyoxime or methylglyoxime are
employed as the starting ligand\ a mixture of fac! and
mer!isomers was obtained[ However\ in some cases
one of them was isolated individually ð02Ł[ In spite
of the fact that clathrochelates are produced by a
multistage mechanism through the formation of semi!
clathrochelate products\ the latter have not been iso!
lated because of their lability[ At the same time\ a
In most cases syntheses of macrobicyclic iron"II# tris!
dioximates occur via a one!step procedure enabling
one to obtain only complexes with identical dioxime
fragments and capping groups ð0Ð6Ł[ It is not expedi!
ent to utilize mixtures of dioximes or capping agents
with similar properties in these processes to produce
asymmetrical compounds because of the formation of
a mixture of products that is close to a statistical one[
The formation of predominantly symmetrical com!
plexes has been observed even when the dioximes and
capping agents used di}er signi_cantly in their proper!
ties[ The former case can be accounted for by the
di}erence of non!macrocyclic tris!dioximates\
described in ð7Ð01Ł as _rst intermediate\ stability con!
1¦
1¦
stants "in case bðFe"H D# Ł ŁbðFe"H D#"H D?#Ł # predomi!
nantly formed symmetrical ðFe"H1D#2Ł1¦ complex
capping for di}erent cross!linking agents due to the
1
2
1
1
ꢀ Author to whom correspondence should be addressed[
3204

3205
Yan Z[ Voloshin et al[
directed synthesis of clathrochelates containing content were carried out with a Carlo Erba model
di}erence dioximate fragments and capping agents 0095 microanalyser[ Iron and tin were determined
allows one to produce functionally substituted pre!
cursors suitable for further functionalization\ as well
as to vary rather _nely the physico!chemical proper!
ties of the products obtained[ The present study was
undertaken to develop new methods for the synthesis
of meridianal! and axial!asymmetrical complexes and
to determine their physico!chemical properties[
spectrophotometrically[
To take FAB spectra\ a high!resolution double!
focusing MX!0209 mass!spectrometer "electrostatic
and magnetic sectors# was used[ The substance to be
investigated was dissolved in tricyanoethoxypropane[
A sample of 4Ð09 ml of the solution was bombarded
by an argon atom beam with an energy of 2[4 keV[
The calibration of the mass number scale in the mass!
spectrometer under FAB conditions was performed
against the peaks of cluster ions[ The analyzer peak
resolution under FAB conditions was usually 09\999[
The relative intensities of the isotope peaks of
molecular and fragment ions were calculated from the
data on the abundance of natural isotopes of all the
elements forming a part of these ions[ The com!
position of molecular or fragment ions in the exper!
EXPERIMENTAL
The reagents used\ FeCl1 = 3H1O\ Fe"BF3#1 = 5H1O\
BF1 = O"C1H4#1\ SnBr3\ sorbents\ n!butyl and phe!
nylboronic acids\ dioximes\ bases\ as well as organic
solvents\ were obtained commercially[ The starting
dioximes designations are shown in Table 0[
The analyses for the carbon\ hydrogen and nitrogen imental mass spectra is con_rmed by comparing the
Table 0[ 46Fe Mossbauer spectra parameters "mm:s# of macrobicyclic iron"II# dioximates
Ã
Compound
Starting dioxime
IS
QS
8 predicted "deg#
FeNx2"BC5H4#"BF#
9[21
9[67
01Ð06
nioxime\ H1Nx
H1Nx
H1Nx
ðFeNx2"BC5H4# = "AlOH#Ł
""n!C3H8#3N#ðFeNx2"BC5H4#"SnCl2#Ł
FeBd2"BF#"Bn!C3H8#
9[26
9[22
9[21
9[25
9[9
9[17
06Ð11
16Ð21
06[8a
a!benzyldioxime\ H1Bd
CH20C1NOH
5
FeDm2"BC5H4#"BF#
9[21
9[43
06Ð11
CH20C1NOH
dimethylglyoxime\ H1Dm
H1Dm\ H1Bd
H1Bd\ H1Gm
H1Dm\ H1Gm
H1Dm\ H1Bd
H1Bd\ H1Nx
H1Nx
H1Nx
H1Nx
H0C0C1NOH
5
FeDm1Bd"BF#1
FeBd1Gm"BF#1
FeDm1Gm"BF#1
FeBd1Dm"BF#1
FeBd1Nx"BF#1
9[23
9[21
9[22
9[20
9[22
9[22
9[18
9[26
9[20
9[36
9[33
9[56
9[26
9[47
9[57
9[50
"−#9[19
9[45
19Ð14
19Ð14
03Ð08
11Ð16
06Ð11
03Ð08
06Ð11
26[4a
FeNx2"BF#1 ð3Ł
FeNx2"BC5H4#1 ð06Ł
"HDEA#1ðFeNx2"SnCl2#1Ł ð4\ 07Ł
FeGm2"BF#1 ð3Ł
06Ð11
H0C0C1NOH
glyoxime\ H1Gm
H1Gm
H1Dm
H1Dm
FeGm2"Bn!C3H8#1 ð08Ł
FeDm2"BF#1 ð19Ł
FeDm2"Bn!C3H8#1 ð06Ł
FeBd2"BF#1 ð10Ł
9[21
9[20
9[22
9[21
9[18
9[73
9[89
9[46
9[14
9[17
09[8a
02[2a
06Ð11
18[2a
16Ð22
H1Bd
H1Bd
FeBd2"Bn!C3H8#1 ð06Ł
a X!ray structure data[

Synthesis\ spectral and electrochemical characteristics of asymmetrical iron"II# tris!dioximates 3206
isotope peak series of these ions with the calculated CaCl1[ After evaporation of chloroform to 19 ml\ a
ones[
solid product was precipitated by addition of a four!
The IR spectra of solid samples "CsI and KBr tab! fold volume of hexane[ The solid was dissolved in a
lets# were recorded in the range from 199 to 3999 cm−0 benzeneÐdiethyl ether "4]0# mixture[ The solution was
on a Specord M!79 spectrophotometer[ The bands dried with CaH1 and precipitated with hexane[ The
were assigned using the previous results[ The UVÐVIS resulting orange product was additionally puri_ed by
spectra of solutions in chloroform were recorded in reprecipitation from a concentrated chloroform solu!
the range from 199 to 799 nm on a Lambda 8 Perkin tion with methanol\ washed with a small amount of
Elmer spectrophotometer[ The individual Gauss com! methanol\ diethyl ether\ hexane and dried in vacuo^
ponents of these spectra were calculated using the yield 0[05 g\ 19)[ Found] C\ 34[3^ H\ 3[9^ N\ 03[2^ Fe\
SPECTRA program[ The 0H\ 02C\ 00B and 008Sn NMR 8[5[ Calc[ for C11H11N5O5B1F1Fe] C\ 34[3^ H\ 2[7^ N\
spectra of the solutions in CDCl2 were recorded on a 03[3^ Fe\ 8[5)[
AC!199 Bruker FT!spectrometer[
FeBd1Dm"BF#1 This complex was synthesized like
46Fe Mossbauer spectra were obtained on YGRS! the previous one except ðFeBd1"BF#1"CH2CN#1Ł
Ã
3M spectrometer with a constant acceleration mode[ "2[57 g\ 4 mmol# and H1Dm "0[05 g\ 09 mmol# were
The spectra were collected on 145 multichannel ampli! used instead of ðFeDm1"BF#1"CH2CN#1Ł and H1Bd^
tude analyzer[ The isomer shift was measured rela! yield 9[77 g\ 14)[ Found] C\ 48[1^ H\ 2[7^ N\ 01[9^ Fe\
tively to sodium nitroprusside and a!Fe foil was used 6[7[ Calc[ for C21H15N5O5B1F1Fe] C\ 48[3^ H\ 2[6^ N\
for the velocity scale calibration[ 46Co in Cr matrix 01[9^ Fe\ 6[8)[
was used as a source\ which was always kept at room
FeDm1Gm"BF#1 This complex was synthesized like
temperature[ The minimum absorption line width in the FeDm1Bd"BF#1 except H1Gm "0[7 g\ 19 mmol# was
the spectrum of a standard sample of sodium nitro! used instead of H1Bd^ yield 9[32 g\ 09)[ Found] C\
prusside was 9[13 mm:s[
16[7^ H\ 2[1^ N\ 08[2^ Fe\ 02[1[ Calc[ for
Cyclic voltammograms were recorded in ace! C09H03N5O5B1F1Fe] C\ 16[8^ H\ 2[2^ N\ 08[4^ Fe\
tonitrile under argon atmosphere using a PI!49!0 02[9)[
potentiostat coupled with a B6!34 tera!ohmic poten!
FeBd1Gm"BF#1 This complex was synthesized like
tiometer as currentÐvoltage convertor[ Tetra! the FeBd1Dm"BF#1 except H1Gm "9[77 g\ 09 mmol#
a
butylammonium tetra~uoroborate "9[0 M# was used was used instead of H1Dm and the reaction was real!
as a supporting electrolyte[ A platinum microelectrode ized at room temperature^ yield 9[36 g\ 03)[ Found]
of 09 mm in diameter\ thoroughly polished and rinsed C\ 42[1^ H\ 2[1^ N\ 01[3^ Fe\ 7[1[ Calc[ for
before measurements\ was chosen as a working elec! C29H11N5O5B1F1Fe] C\ 42[0^ H\ 2[1^ N\ 01[3^ Fe\ 7[1)[
trode[ A platinum wire was applied as an auxiliary
FeBd1Nx"BF#1 This complex was synthesized like
electrode[ An SCE reference electrode was connected the FeBd1Dm"BF#1 except H1Nx "9[60 g\ 4 mmol# was
to the cell via a salt bridge[ All potentials were referred used instead H1Dm and the reaction was realized at
to the redox potential of the ferrocene "Fc¦:Fc# couple room temperature^ yield 0[06 g\ 21)[ Found] C\ 44[5^
as an internal standard[ This potential is at ¦9[399 V H\ 2[6^ N\ 00[3^ Fe\ 6[5[ Calc[ for C23H17N5O5B1F1Fe]
vs SCE under the present experimental conditions[
C\ 44[7^ H\ 2[7^ N\ 00[4^ Fe\ 6[5)[
FeNx2"BC5H4#"BF#1 Preliminarily immobilized
semiclathrochelate FeNx2"BC5H4# = "AlO"OH##n com!
plex was obtained[ Specially prepared aluminium
oxide hydroxide was produced by dissolving an alu!
Syntheses of complexes
ðFeDm1"BF1#1"CH2CN#1Ł\ ðFeBd1"BF1#1"CH2CN#1Ł minium foil "43 g\ 1 mol# in 0[4 l absolute iso!propanol
and ðFe"H1Nx#2ŁCl1 complexes were obtained as after activation with HgCl1[ The resulted solution was
described previously ð03\ 04Ł[
treated with a waterÐiso!propanol mixture "199 and
FeDm1Bd"BF#1 ðFeDm1"BF1#1"CH2CN#1Ł "3[53 g\ 149 ml\ respectively#\ stirred for 1 h\ _ltered and the
09 mmol# was dissolved:suspended in dry acetonitrile precipitate was dried in vacuo at 049>C[ 19 g AlO"OH#
"29 ml# which had been degassed with argon[ Then obtained as described above was placed under argon
H1Bd "3[7 g\ 19 mmol# and N\N!diisopropylethyl stream into a solution of FeCl1 = 3H1O "1[3 g\ 01 mmol#
amine "2[5 ml\ 19 mmol# were added to the stirred and H1Nx "7[4 g\ 59 mmol# in 199 ml of acetonitrile[
reaction mixture[ The redÐviolet solution was heated The suspension was stirred for 29 min and the solution
at 39Ð49>C for 09 min\ then BF2 = O"C1H4#1 "1[7 ml\ of phenylboronic acid "1[33 g\ 19 mmol# and dicy!
11 mmol# and N\N!diisopropylethyl amine "2[5 ml\ clohexyl amine "3 ml\ 19 mmol# in 49 ml acetonitrile
19 mmol# were added dropwise[ After a reaction time was added dropwise[ The reaction mixture was left
of 29 min\ BF2 = "C1H4#1O "1[7 ml\ 11 mmol# was overnight at 39>C and _ltered[ The precipitate was
added\ the reaction mixture was heated to 79>C\ stir! washed with acetonitrile "199 ml#\ chloroform
red for 19 min and _ltered[
"149 ml#\ 049 ml of methylene dichloride with phenyl!
The _ltrate was treated in a three!fold volume of boronic acid "0[11 g\ 09 mmol# and extracted with
water and the product was extracted with chloroform methylene dichloride in a Soxhlet extractor for about
"49 ml#[ The extract was washed with a 4) NaOH 59 h to decolored of extragent[ The solid after extrac!
aqueous solution\ water and dried with anhydrous tion was dried in air^ yield ½14 g[

3207
Yan Z[ Voloshin et al[
The product obtained "09 g# was suspended in a "4 ml# in acetonitrile "4 ml# was added[ The reaction
mixture of ethyl acetate "19 ml# and BF2 = O"C1H1#1 mixture was stirred for 19 min\ _ltered and the solid
"4 ml#\ stirred for 0 h\ _ltered and the _ltrate was was washed with chloroform[ The _ltrate was added
washed with aqueous sodium carbonate[ The solid to the _rst one and the solution was washed with
was washed with ethyl acetate "19 ml# and this _ltrate aqueous Na1CO2\ water\ dried with CaCl1\ evaporated
was added to the _rst one[
to ½1 ml and precipitated with heptane[ The solid
The resulted solution was washed with water\ dried was reprecipitated from chloroform with heptane and
with Na1SO3 and evaporated to dryness[ The product dried in vacuo^ yield 9[26 g\ 28)[ Found] C\ 59[4^ H\
obtained was washed with a small amount of diethyl 3[7^ N\ 09[3^ Fe\ 5[7[ Calc[ for C39H28N5O5B1FFe] C\
ether\ reprecipitated from methylene dichloride with 59[3^ H\ 3[8^ N\ 09[5^ Fe\ 6[9)[
heptane and dried in vacuo^ yield 9[0 g\ 2[4)[ Found]
""n!C3H8#3N#ðFeNx2"BC5H4#"SnCl2#Ł The solution
C\ 37[4^ H\ 3[7^ N\ 03[2^ Fe\ 8[2[ Calc[ for of ðFe"H1Nx#2ŁCl1 "3[4 g\ 7 mmol#\ nioxime "9[8 g\
C13H18N5O5B1FFe] C\ 37[5^ H\ 3[8^ N\ 03[1^ Fe\ 8[3)[ 5 mmol# and aluminium oxide "neitral\ Brockman I\
The ðFeNx2"BC5H4# = Al"OH#Ł complex was also 34 g# in acetonitrile "049 ml# was stirred for 09 h and
obtained from the above!mentioned immobilized _ltered[ The solid was washed with acetonitrile and
complex by basic decomposition with NaOH and ""n! dried in vacuo[ Re~ux of the obtained product with
C3H8#3N#OH followed by extraction with a benzeneÐ phenylboronic acid "2[6 g\ 29 mmol# and nioxime
THF "0]1# mixture[ The resulted solution was pre! "9[3 g\ 2 mmol# in benzene "199 ml# for 2 h resulted
cipitated with heptane and reprecipitated from a in a solid\ which was _ltered\ washed with benzene
THFÐdiethyl ether "0]2# mixture with heptane and "099 ml#\ chloroform "299 ml# and acetonitrile "149 ml#
dried in vacuo[
and dried in vacuo^ yield 49 g[
The FeNx2"BC5H4#"BF# complex can also be
The solid was suspended in an acetonitrileÐchloro!
obtained from FeNx2"BC5H4#1[ This compound "1 g\ form "0]0# mixture "299 ml# and a solution of SnCl3
2 mmol# and triethyloxonium ~uoroborate "0[73 g\ "09 ml\ 7[5 mmol# in chloroform "49 ml# was added
09 mmol# were suspended:dissolved in 04 ml of meth! dropwise under vigorous stirring[ After a reaction
ylene dichloride and stirred for 49 h at room tem! time of 04 min at room temperature the solution was
perature[ The reaction mixture was washed with _ltered\ washed at 9>C with ""n!C3H8#3N#Cl aqueous
aqueous NaHCO2\ monoethanolamine\ water\ dried solution "09)\ 49 ml\ two times# and water "099 ml\
with K1CO2\ evaporated to ½09 ml and precipitated two times# and dried with anhydrous MgSO3[ The
with heptane[ The solid was separated by chro! mixture of solid ""n!C3H8#3N#1ðFeNx2"SnCl2#1Ł and ""n!
matography on Silasorb C!299 "eluent] chloroformÐ C3H8#3N#ðFeNx2"BC5H4#"SnCl2#Ł complexes was
iso!propanol "099]0## and the products were isolated obtained by precipitation from chloroform extract
"FeNx2"BC5H4#1] 9[2 g\ FeNx2"BC5H4#"BF#] 9[14 g\ with heptane[
FeNx2"BF#1] 9[12 g#[
The precipitate was dissolved in THF and the for!
FeDm2"BC5H4#"BF# This complex was synthesized mer complex was precipitated with a two!fold volume
like the previous one except H1Dm "6[9 g\ 59 mmol# of diethyl ether[ The _ltrate\ containing the latter one\
was used instead of nioxime^ yield 9[01 g\ 4)[ Found] was treated with a _ve!fold volume of pentane[ The
C\ 31[9^ H\ 3[2^ N\ 05[1^ Fe\ 09[6[ Calc[ for obtained solid product was reprecipitated\ washed
C07H12N5O5B1FFe] C\ 30[8^ H\ 3[4^ N\ 05[2^ Fe\ 09[7)[ with a small amount of diethyl ether\ pentane and
FeBd2"BF#"Bn!C3H8# The starting Fe"HBd#1"H1Bd# dried in vacuo^ yield 9[7 g\ 09)[ Found] C\ 35[7^ H\
complex was obtained by re~ux of sus! 5[1^ N\ 8[4^ Fe\ 4[3^ Sn\ 00[6[ Calc[ for C39H54N6O5B!
pension:solution of FePy3Cl1 "7[75 g\ 19 mmol# and Cl2FeSn] C\ 35[4^ H\ 5[2^ N\ 8[4^ Fe\ 4[3^ Sn\ 00[4)[
H1Bd "03[3 g\ 59 mmol# in 019 ml ethanol[ The reac!
tion mixture was _ltered and water "399 ml# was added
to the _ltrate[ After precipitation the solid was _ltered\
RESULTS AND DISCUSSION
washed with water and aqueous ethanol "19)# and
Meridianal!asymmetrical iron"II# clathrochelates
dried in vacuo^ yield 09[4 g\ 69)[
were obtained by the cycloaddition of a!dioximes
Immobilized
semiclathrochelate
FeBd2"Bn!
"H1D# to preliminarily synthesized planar!square
macrocyclic iron"II# bis!dioximates by the following
reaction]
C3H8# = "AlO"OH##n was obtained using AlO"OH# sor!
bent\ prepared as described above[
ðFe"HBd#"H1Bd#Ł complex "4[9 g\ 5[4 mmol# and the
above!mentioned sorbent "09 g# were stirred for
29 min in acetonitrile "099 ml# at 39>C and a solution
of n!butylboronic acid "9[81 g\ 09 mmol# in acetonitrile
"14 ml# was added dropwise[ The reaction mixture was
ðFeD1"BF1#1"CH2CN#1Ł¦H1D?
:FeD1D?"BF#1¦1HF[
It is obvious that this reaction is favored by binding
stirred for 3 h at 49>C\ _ltered and the solid was tre! the HF acid released during its course\ i[e[\ in the
ated as described for FeNx2"BC5H4# = "AlO"OH##n^ presence of H¦ and F− ion acceptors[ A weakly coor!
yield 02[3 g[
dinating sterically hindered N\N!diisopropylethyl
The obtained product "1[4 g# was suspended in amine and boron tri~uoride etherate were used as H¦
chloroform "14 ml# and a solution of BF2 = O"C1H4#1 ion acceptor and electrophilic agent to remove F−

Synthesis\ spectral and electrochemical characteristics of asymmetrical iron"II# tris!dioximates 3208
ions\ respectively[ In addition\ BF2 = O"C1H4#1 has pre! We have managed to obtain an axial!asymmetrical
vented the side elimination reactions of capping FeNx2"BC5H4#"BF# complex\ along with the sym!
boron~uoride groups "Scheme 0#[ metrical products\ via a {{re!boronating|| reaction
The above reaction proceeds under more rigid con! from the preliminarily formed FeNx2"BC5H4#1
ditions and takes more time than a direct template attacked by triethyloxonium ~uoroborate\ the com!
condensation on the iron"II# ion that can be accounted plex was isolated using chromatography "Scheme 2#[
for by the fact that the overall mechanism of cla!
This\ however\ cannot be a general method[ Our
throchelate synthesis involves\ as mentioned above\ attempts to prepare the FeDm2"BC5H4#"BF# complex
an intermediate tris!complex formation step ð7Ð01Ł[ It by an analogous scheme have not been successful]
is evident that macrocyclic planar!square iron"II# bis! only a symmetrical FeDm2"BF#1 complex has been
dioximates are relatively kinetically stable\ and the formed[
addition of a third dioxime molecule involves not only
The synthesis of axial!asymmetrical clathrochelate
detachment of an axially coordinated solvate ligand\ iron"II# dioximates were realized through a stepwise
but also considerable rearrangements in the nearest {{assembling|| on the sorbent surface "Scheme 3#[
coordination environment\ which is\ naturally\
A chemical immobilization of a nonmacrocyclic
accompanied by an appreciable consumption of tris!complex on the matrix surface has enabled us to
energy[
protect one of its two triangular planes formed by
In the absence of F− ion acceptors\ a clathrochelate oxime groups "Ia# and to obtain the immobilized semi!
is not formed and the reaction completes at a stage of clathrochelates via capping by Lewis acids[ The
cis!addition of the protonated dioxime to a planar! desorption of these semiclathrochelates "IIa# with the
square macrocycle[ In the absence of the base B with help of another capping agent leads to the formation
certain dioximes "H1Nx and H1Dm#\ the reaction of asymmetrical clathrochelate "IIIa#[
yields a mixture of symmetrical clathrochelates[ In
other cases\ only a mixture of decomposition products procedure is governed by a sorbent aptitude for a
has been formed[ speci_c binding of the starting tris!complex "Ia# and
The success of the synthesis carried out by this
A direct synthesis of axial!asymmetrical tris!dioxi! the subsequent desorption of a semiclathrochelate
mate iron"II# clathrochelates via the formation of sem! "IIa# a}ected by a capping agents[
iclathrochelate complexes of type II\ without
We have examined more than ten sorbents based on
application of protecting groups\ could not be realized aluminium\ titanium\ silicon oxides and hydroxides[
even in a great excess of complex I since a compound Di}erent sorbents\ based on silicon dioxide\ adsorb
of type II readily disproportionates to give I and III nonmacrocyclic iron"II# tris!dioximates yielding com!
"Scheme 1#[
plexes of type Ia which\ after the _rst capping\ are
Scheme 0[

3219
Yan Z[ Voloshin et al[
Scheme 1[
Scheme 2[
desorbed by BF2 = O"C1H4#1 to give clathrochelates of tion capacity towards Ia[ The latter is\ however\ apt
type IIIa[ However\ they display a low sorbtion to desorption to give IIIa\ when treated with capping
capacity towards Ia[ With silicon"IV# hydroxide\ agents[
obtained by hydrolysis of silicon"IV# tetraethoxyde\
Aluminium"III# oxides show results depending\ to
no compounds of type IIa have been formed[ The a great extent\ on the method of sorbents formation
titanium"IV# hydroxide resulted from hydrolysis of and treatment[ As a whole\ however\ the degrees of
titanium"IV# tetrabutoxyde exhibits a very high sorp! both desorption and purity of the formed product IIIa

Synthesis\ spectral and electrochemical characteristics of asymmetrical iron"II# tris!dioximates 3210
Scheme 3[
are low[ The aluminium"III# hydroxide resulted from re~ects a so!called {{macrocyclic|| e}ect of ligand _eld
corrosion of amalgamated aluminium does not tend increase upon formation of a clathrochelate structure
to the formation of complexes of type IIa[
The best results were obtained with aluminium
ð3Ł[
A quadrupole splitting "QS# in the 46Fe Mossbauer
hydroxide resulted from hydrolysis of aluminium"III# spectra\ which characterize the electric _eld gradient
iso!propylate[ A high sorption capacity "ca[ 09)# of on the iron nucleus\ characterizes a twist angle 8 of
compounds Ia\ a high degree of desorption of com! a coordination polyhedron intermediate between a
plexes IIa and the purity of clathrochelates IIIa for! trigonal prism "TP\ 8ꢁ9>\ QS½¦0 mm:s# and a tri!
med make aluminium"III# hydroxide the most suitable gonal antiprism "TAP\ 8ꢁ59>\ QS½−9[2 mm:s#[ The
agent for the synthesis of targeted compounds[
A hydrolytic decomposition of the immobilized help of a correlation curve {{QS vs 8|| proposed in
nioximate FeNx2"BC5H4# = "AlO"OH##n semi! ð3Ł or calculated from a new version of the partial
clathrochelate by a mixture of aqueous NaOH and quadrupole splitting concept ð05Ł[
""n!C3H8#3N#OH solutions enables one to isolate the In the clathrochelate ligand _eld\ binding t1g!level
product having
hypothetical composition as of iron"II# with an electronic d5 con_guration splits
8 value for each complex may be predicted with the
a
ðFeNx2"BC5H4# = "AlOH#Ł detectable in FAB mass into e0 and a0 levels[ In case of TP geometry\ the energy
spectrum\ and to obtain clathrochelates quantitatively of the e0 level is higher than that of a0 and the QS sign
by reactions with Lewis acids[ Unfortunately\ we is positive[ For TAP geometry\ e0 is lower in energy
failed to isolate and characterize this product as a pure than a0 and the QS sign is negative[ The inversion of
one with no admixtures because it readily dis! these levels takes place at 8¼29>[ All boron!con!
proportionates and oxidizes[
taining macrobicyclic tris!dioximates of known struc!
For all synthesized compounds "except the mixed ture have a TP geometry ð05Ł and\ hence\ a positive
borontin!containing one# the most intensive ðM¦H¦Ł¦ QS value[ There are good reasons to believe that the
molecular ions were detected in FAB mass spectra[
QS in the synthesized boron!containing complexes has
The main spectral parameters of the synthesized also a positive sign[ This fact is con_rmed by an
clathrochelates are typical for clathrochelate iron"II# appreciable QS absolute value in the majority of the
tris!dioximates ð3\ 4Ł[ The isomer shift "IS# values in synthesized compounds and allows one to predict the
46Fe Mossbauer spectra "Table 0#\ which is deter! 8 values listed in Table 0[ The QS values for mer!
minated by the s!electron density on the iron nucleus\ idianal!asymmetrical clathrochelates are intermediate
are characteristic for low!spin iron"II# complexes and between those for the corresponding symmetrical
markedly lower than those for analogous non! complexes of the known structure[
macrocyclic tris!dioximates[ This phenomenon
The introduction of some {{new|| dioximate frag!

3211
Yan Z[ Voloshin et al[
ments into the clathrochelate cage\ as a rule\ exerts complex chromophore system than that of sym!
much more on the QS and 8 values than in the case metrical clathrochelates\ while the spectra for boron!
when a second such fragment is introduced[ The above containing axial!asymmetrical compounds closely
statements are clearly shown for a!benzydioxime in resemble those of the corresponding symmetrical com!
Table 1[
pounds[ It should be noted that the UVÐVIS spectra
A similar phenomenon was observed upon intro! for the latter with the same dioxime and di}erent
duction of glyoximate and nioximate fragments into boron!containing capping fragments are practically
the clathrochelate framework instead of a!benzyl! identical ð3\ 06Ł[ The spectrum for a mixed borontin!
dioximate and dimethylglyoximate ones[
containing ""n!C3H8#3N#ðFeNx2"BC5H4#"SnCl2#Ł cla!
For axial!asymmetrical complexes\ just like for throchelate alone essentially di}ers from that for the
symmetrical boron!containing iron"II# tris!dioximates FeNx2"BC5H4#1 complex] apart from a singlet band
ð3\ 05Ł\ distinct dependencies of QS and 8 values on about 359 nm characteristic for boron!containing
the nature of a substituent at the boron atom have compounds\ a more intense band appears about
been obtained[ꢀ The QS value in a mixed borontin! 499 nm detectable in the UVÐVIS spectrum for a tin!
containing clathrochelate is equal to zero which is in chloride tris!dioximate ðFeNx2"SnCl2#1Ł1− dianion[
agreement with the above statements too] the QS value The intensities of these bands are redistributed "Table
in the corresponding trigonal!prismatic boron!con! 2#[
taining FeNx2"BC5H4#1 complex has a positive sign\
An analogous phenomenon was also observed in
while the corresponding trigonal!antiprismatic tin! the spectra of some meridianal!asymmetrical clathro!
containing clathrochelate\ according to the data chelates "FeDm1Bd"BF#1\ FeBd1Dm2"BF#1 and
reported in ð4\ 07Ł\ is characterized by a negative QS FeBd1Nx1"BF#1#[ The intense Md:Lpꢀ charge trans!
value[ A superposition of these two contributions fer band in the UVÐVIS spectra of these compounds
gives a twist angle 8 close to 29> and\ hence\ the QS proved to be a superposition of two bands with max!
value is zero[
ima slightly shifted to the long!wavelength range as
The UVÐVIS spectra for synthesized meridianal! compared to the corresponding symmetrical com!
asymmetrical compounds in solution indicate a more plexes ""FeDm2"BF#1\ FeBd2"BF#1 and FeNx2"BF#1#\
but at an unusual and unexpected ratio of the inten!
sities of these bands takes place[
The UVÐVIS spectrum for the FeBd1Gm"BF#1 com!
one axial!asymmetrical complex "Fig[ 0# was solved ð19Ł[ plex proved also to be quite unexpected since it con!
ꢀ After sending this paper to the Editor the structure of
Single
crystals
of
the
FeBd2"BF#"Bn!
tains only one band with the intermediate value of
lmaxꢁ353 nm\ rather than two bands at approxi!
mately 339 and 379 nm[ With this complex\ maximal
tension in p!systems of di}erent dioxime fragments is
presumably observed[ Since UVÐVIS spectral charac!
teristics of FeDm2"BF#1 and FeGm2"BF#1 complexes
are identical in the visible part\ the charge transfer
band in the spectrum for an asymmetrical
FeDm1Gm"BF#1 clathrochelate is nearly the same as
C3H8# = C5H4CH2 = 0C7H05 complex were obtained by slow
1
evaporation of the saturated solution in a tolueneÐcyclooc!
tane "0]2# mixture for several weeks[ Due to the partial decay
of the sample it turned out to be impossible to get a larger
data set[ Moreover one of the phenyl rings is disordered\ the
rest were re_ned in a {{rigid!body|| approximation[ However\
the structure is the _rst example of asymmetric cla!
throchelates and the data obtained allow to analyze the coor!
dination
environment
of
the
central
atom[
C46H44B1FFeN5O5\ crystal size 9[25×9[17×9[11 mm\ that for the _rst two complexes[ In this case the band
¹
Mꢁ0904[63\ triclinic\ space group P0\ aꢁ09[741"1#\
positions of intraligand pÐpꢀ transitions di}er from
that for symmetrical compounds[
The asymmetry of the synthesized complexes mani!
fests itself in their IR and NMR spectra "Tables 2 and
Ä
bꢁ03[960"2#\ cꢁ06[949"2# A\ aꢁ76[52"2#>\ bꢁ76[35"2#>\
gꢁ79[19"2#>\ Uꢁ1450[4"8# A \ Zꢁ1\ Dcꢁ0[001 g cm−2
\
2
Ä
mꢁ9[234 mm−0\ F"999#ꢁ0919[1781 independent re~ections
were collected at 182 K on a CAD3 di}ractometer using Mo!
3#[ The C N and NÐO stretching vibrations in the
1
Ä
Ka
radiation
"lꢁ9[60962 A#
with
u:1u
scans
dioxime fragments of meridianal!asymmetrical cla!
throchelates and in the mixed borontin!containing
axial!asymmetrical complex proved to be the most
sensitive ones[ These vibrations may be assigned to the
"0[75>³u³08[87>#[ The structure was solved by the heavy!
atom method\ re_nement was made by a full!matrix least
squares an F1 for all data with anisotropic displacement
parameters for non!hydrogen atoms and isotropic for hydro!
gen atoms^ goodness!of!_tꢁ0[967\ _nal R indices "I×1s"I## corresponding dioximate groups or their fragments
R0ꢁ9[9681\ wR1ꢁ9[1003\
w−0ꢁs1"F1o#¦"9[041P#1
bound to a certain type of an capping groups[ In
particular\ the stretching vibrations of the C N band
in the spectrum of the FeDm1Gm"BF#1 complex are a
superposition of two signals] one about 0459 cm−0
which may be assigned to a glyoximate fragment "for
the FeGm2"BF#1 clathrochelate\ it is detected at
0448 cm−0# and at 0472 cm−0\ which may be assigned
¦05[863P\ Pꢁ"F1o¦1Fc1#:2[ The main parameters of the
1
Ä
iron"II# coordination polyhedron "FeÐN distance is 0[78 A
and NÐFeÐN bite "chelate# angle is 28[4># are characteristic
for macrobicyclic iron"II# tris!dioximates[ The smaller dis!
tortion angle value "8ꢁ06[8># than estimated from 46Fe
\
Mossbauer parameters "Table 0\ for analogous FeBd "BF#
Ã
2
1
complex with similar QS value distortion angle signi_cantly
higher\ 8ꢁ18[2># accounted for the electronÐdonor e}ect of
n!butyl substituent at boron atom rather than an electron!
acceptor e}ect of the ~uorine substituent[
to
dimethylglyoximate
fragments
"for
the
FeDm2"BF#1 clathrochelate\ it is detected at
0474 cm−0#[ The same vibration in the IR spectrum

Synthesis\ spectral and electrochemical characteristics of asymmetrical iron"II# tris!dioximates 3212
Fig[ 0[ Molecular structure of the FeBd2"BF#"Bn!C3H8# complex[ Hydrogen atoms are omitted and one of the two disordered
phenyl groups C"08#ÐC"13# are shown[
Table 1[
FeDm2"BF#1
FeDm1Bd"BF#1
FeDmBd1"BF#1
FeBd2"BF#1
QS "mm:s#
DQS "mm:s#
8 "deg#
9[89
9[36
9[32
19Ð14
9[26
9[09
11Ð16
9[14
9[01
18[2
9[11 "increment Dm:Bd#
02[2
for the mixed borontin!containing compound appears cm−0 ð4Ł# and a band at 0462 cm−0 "for the FeNx2
in the form of a band at 0454 cm−0 "for the "BC5H4#1 complex n"C N#ꢁ0479 cm−0 ð06Ł#\ which
"HDEA#1ðFeNx2"SnCl2#1Ł complex n"C N#ꢁ0457 can be attributed to the oxime fragments bound to
1
1

3213
Yan Z[ Voloshin et al[
Table 2[ IR "cm−0# and UVÐVIS spectra parameters of macrobicyclic iron"II# dioximates
Compound
n"C
1
N#
n"NÐO#
n"BÐO#
l "nm# "o×092 mol−0 l cm−0
#
FeNx2"BC5H4#"BF#
FeDm2"BC5H4#"BF#
FeBd2"BF#"Bn!C3H8#
""n!C3H8#3N#ðFeNx2"BC5H4#"SnCl2#Ł
FeDm1Bd"BF#1
0479
847\ 0950
0083m
167"6[3#\ 132"1[3#\ 241"0[6#\
336"05#
115"00#\ 132"2[6#\ 155"5[7#\
296"1[0#\ 339"03#
153"20#\ 181"06#\ 210"2[8#\
306"3[0#\ 370"18#
173"01#\ 214"2[6#\ 247"0[2#\
0466m
822\ 839\ 0982 0086m
821\ 830\ 0951 0194m
846\ 0949\ 0945 0085m
0472m
0454\ 0462
0471m
205 "SnCl2# 352"2[8#\ 386"6[3#
0085m
821\ 849\
0941m\ 0096
151"01#\ 172"04#\ 258"1[4#\
343"01#\ 382"09#
FeBd1Dm"BF#1
0472\ 0591
0471\ 0477
829\ 832\ 0950\ 0086m
0979sh
822\ 844\ 0959\ 0086m
159"36#\ 178"07#\ 187"3[5#\
344"07#\ 381"02#
147"15#\ 189"05#\ 209"3[1#\
348"08#\ 382"01#
FeBd1Nx"BF#1
FeDm1Gm"BF#1
0459sh\ 0472 829sh\ 835\
0974m
0089m
159"09#\ 231"1[9#\ 330"03#
FeBd1Gm"BF#1
0451\ 0476
620\ 834\ 0952\
0973
145"24#\ 170"6[5#\ 263"2[8#\
353"12#
FeNx2"BOH#1 ð3Ł
0473
854\ 0969
0089m
165"4[5#\ 186"1[1#\ 395"2[2#\
335"04#
FeBd2"BF#1 ð3Ł
FeDm2"BF#1 ð3Ł
FeGm2"Bn!C3H8#1 ð08Ł
0471
0474
0448
835\ 0954
838\ 0983
834\ 0986
0101m
0083m
0196m
146"27#\ 189"6[1#\ 397"3[1#\ 368"12#
155"5[9#\ 280"1[2#\ 339"04#
176"7[1#\ 186"3[9#\ 283"3[2#\
328"02#
"HDEA#1ðFeNx2"SnCl2#1Ł ð4Ł
0457
857\ 0935
209 "SnCl2# 187"06#\ 368"6[1#\ 447"5[1#
tin! and boron!containing capping fragments\ respec! reveal signals for the both caps] a broadened singlet
tively[ The IR spectrum obtained for the later clathro! of alkyl! or arylborate and a doublet of boron~uoride
chelate also clearly shows intense characteristic bands tetrahedral "judging from the d00B value# fragments[
of stretching vibrations for both capping fragments The value of a spinÐspin coupling constant "J00BÐ08F
"n"BÐO# at approximately 0199 and n"SnÐCl# at is approximately 04 Hz# indicates a high symmetry for
approximately 219 cm−0 ð3\ 4Ł#[ It should also be the BO2F fragment[ The same symmetry of capping
stressed that for a distorted TAP a!benzyldioximate boron~uoride fragments was detected in meridianal!
FeBd2"BF#1\ the n"BÐO# bands have been observed at a asymmetrical clathrochelates "Table 3#[ In the 008Sn
higher frequency "0101 cm−0# than for its meridianal! NMR spectrum for the mixed compound in solution\
asymmetrical derivatives "for FeBd1Dm"BF#1 and an octahedral SnO2CI2 fragment manifests itself as a
FeDm1Bd"BF#1 complexes n"BÐO#ꢁ0086 and singlet "d008Snꢁ−559 ppm# which is slightly di}erent
0085 cm−0\ respectively# with a geometry close to TP from the chemical shift value in the case of a sym!
"see above#[ For the trigonal!prismatic FeDm2"BF#1 metrical ðFeNx2"SnCl2#1Ł1− dianion "d008Snꢁ−539
complex this band was detected at 0083 cm−0 ð3Ł[
The use of the polynuclear NMR spectroscopy has
ppm#[
The above mentioned nonadditivity e}ect of the
allowed us to con_rm the composition of the asym! introduction of a!benzyldioximate fragments instead
0
metrical clathrochelates obtained with the help of the of dimethyldioximate ones in the series of H NMR
integral intensity ratios of the signals in the 0H NMR spectral characteristics of meridianal!asymmetrical
spectra for the protons in the dioxime fragments\ sub! complexes with a!benzyldioxime and dimethyl!
stituents at the boron atom and the tetra! glyoxime was clearly observed] the introduction of the
butylammonium cation "for the mixed borontin! _rst fragment increases chemical shifts in the methyl
containing compound#[ The spectrum for the axial! protons by approximately 9[1 ppm\ while the appear!
asymmetrical
FeDm2"BC5H4#"BF#
dimethyl! ance of the second diphenyl chelate ring only by
glyoximate also reveals the nonequivalence of methyl 9[95 ppm "Table 3#[
substituents[ The nonequivalence of dioximate ring
The cyclic voltammograms of synthesized iron"II#
fragments in axial!asymmetrical clathrochelates is still clathrochelates demonstrate the quasi!reversible
more pronounced in the 02C"0H# NMR spectra "Table waves assigned to Fe1¦:Fe2¦ couple in the anodic
3#[ The 00B NMR spectra for these complexes "except range ð11Ł[ The position and shape of the waves do
for the mixed borontin!containing clathrochelate# not practically depend on the scan rate within the

Synthesis\ spectral and electrochemical characteristics of asymmetrical iron"II# tris!dioximates 3214
Table 4[ Electrochemical characteristics of meridianal! and
axial!asymmetrical iron"II# clathrochelates in acetonitrile
Compound
E0:1 "mV#a
DE "mV#b
FeDm2"BF#1
9[674
9[749
9[899
9[839
9[139
9[274
9[524
9[609
9[634
9[779
9[659
9[039
59
69
69
69
019
54
59
74
79
69
59
79
FeDm1Bd"BF#1
FeDmBd1"BF#1
FeBd2"BF#1
ðFeNx2"SnCl2#1Ł1−
ðFeNx2"BC5H4#"SnCl2#Ł−
FeNx2"BC5H4#1
FeNx2"BF#"BC5H4#
FeNx2"BF#1
FeBd2"BF#"Bn!C3H8#
FeBd2"Bn!C3H8#1
Fe"HBd#1"H1Bd#
a Vs Fc¦:Fc inner standard[
b The Tomes criterion] DEꢁE2:3−E0:3
[
³
interval of 4Ð099 mV s−0 but depend on the sub!
stituents in the ligand dioxime fragments and capping
groups[ Table 4 lists the half!wave oxidation poten!
tials for meridianal!asymmetrical mixed dimethyl!
glyoximateÐa!benzyldioximate complexes[ A decrease
in the electron!donating e}ect of phenyl groups as
compared to methyl groups must lead to the reduction
in electron density on the iron atom and shift the
oxidation potential to the anode range[ As can be seen
from Table 4\ the observed shifts in the oxidation
potential really decrease with increasing the number
of a!benzyldioximate fragments in the complex\ but
there appears a nonadditivity of shifts\ which cor!
relates with the 46Fe Mossbauer\ UVÐVIS and NMR
Ã
spectroscopic evidences indicating the major changes
in the complex structure upon introduction of the _rst
a!benzyldioximate fragment[
Table 4 also represents the results of a cyclic vol!
tammetric study of axial!asymmetrical clathro!
chelates[ In this case\ a certain rise in E0:1 potential
was observed with increasing the inductive Taft con!
stant "dI# ð12Ł of the substituent at the boron atom in
the n!C3H8 "−9[95#³C5H4 "9[09#³F "9[41# series[
Tin!containing compounds are also worth to be
considered] an appreciable e}ect of negatively charged
SnO2Cl2 fragments is evident\ though it was not
determined experimentally[ In this case the appear!
ance of the _rst substituent with ¦I!e}ect has
a far greater in~uence on the magnitude of E0:1
than the introduction of the second one "Table 4^ for
nioxime] "BC5H4#1:"BC5H4#"BF# "¦9[964 V#:"BF#1
"¦9[924 V#^ "SnCl2#1:"SnCl2#"BC5H4# "¦9[034 V#:
"BC5H4#1
"¦9[149 V#^
for
a!benzyldioxime]
"Bn!C3H8#1:"Bn!C3H8#"BF#
"¦9[979 V#:"BF#1
"¦9[959 V##[
In the case of meridianal!asymmetrical complexes
the nonadditivity of the shifts in the iron oxidation
potentials has also been observed in passing from

3215
Yan Z[ Voloshin et al[
7[ Voloshin\ Y[ Z[\ Kostromina\ N[ A[\ Nazarenko\
A[ Y[\ Polshin\ E[ V[ and Tyukhtenko\ S[ I[\
Theor[ Exp[ Khim[\ 0878\ 14\ 211[
8[ Voloshin\ Y[ Z[\ Kostromina\ N[ A[ and Naza!
renko\ A[ Y[\ Ukr[ Khim[ Zh[\ 0882\ 48\ 340[
09[ Voloshin\ Y[ Z[ and Noskov\ Y[ G[\ Ukr[ Khim[
Zh[\ 0882\ 48\ 236[
00[ Voloshin\ Y[ Z[\ Noskov\ Y[ G[\ Terekhova\ M[
I[ and Kron\ T[ E[\ Ukr[ Khim[ Zh[\ 0882\ 48\ 120[
01[ Voloshin\ Y[ Z[\ Noskov\ Y[ G[\ Terekhova\ M[
I[ and Kron\ T[ E[\ Polish J[ Chem[\ 0885\ 69\
0118[
02[ Zavodnik\ V[ E[\ Belsky\ V[ K[\ Voloshin\ Y[ Z[
and Varzatsky\ O[ A[\ J[ Coord[ Chem[\ 0882\ 12\
86[
03[ Thompson\ D[ W[ and Stynes\ D[ V[\ Inor`[
Chem[\ 0889\ 18\ 2704[
04[ Turta\ K[ I[\ Stukan\ R[ A[\ Bulgak\ I[ I[\ Batyr\
L[ G[ and Ozol\ L[ D[\ Koord[ Khim[\ 0867\ 3\
0280[
05[ Nazarenko\ A[ Y[\ Polshin\ E[ V[ and Voloshin\
Y[ Z[\ Mendeleev Commun[\ 0882\ 34[
06[ Voloshin\ Y[ Z[\ Dr[ Sc[ "Prof[# Thesis\ Ivanovo\
0882[
dimethylglyoximates to a!benzyldioximates Dm2:
Dm1Bd "¦9[954 V#:DmBd1 "¦9[949 V#:Bd2
"¦9[939 V#[ꢀ
Acknowled`ements*Support of the Russian Fund of Fun!
damental Researches "Grant N85!92!22401a# is gratefully
acknowledged[
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ꢀ Complete tables of atomic coordinates\ thermal par!
ameters\ bond length and angles have been deposited at the
Cambridge Crystallographic Data Centre "CCDC# and also
are available from Professor Y[ Z[ Voloshin on request[