Synthesis, structure, spectra and magnetic properties of the unsymmetrical oxo-bridged complex [Fe2O(OAsPh3)4Cl3] 2[Fe2OCl6].2CH3CN

Article abstract of DOI:10.1016/S0277-5387(98)00094-1

A new unsymmetrical (μ-oxo)diiron(III) complex [Fe₂O(OAsPh₃)₄Cl₃] ₂[Fe₂OCl₆].2CH₃CN (I), where OAsPh₃ is triphenylarsine oxide, has been prepared by several ways and characterized by X-ray structural analysis, elemental analysis, spectral and magnetic methods. The complex (I) is formed simultaneously with another two complexes of the composition [Fe₂O(OAsPh₃)₄Cl₃][FeCl ₄].CH₃CN (II) and [Fe(OAsPh₃)₄Cl₂] [ FeCl₄] (III). In compound (I) the complex cation has one Fe atom coordinated by four OAsPh₃ which form a plane, and the oxo-bridged ligand occupies an apex and form a square pyramid configuration about the second iron atom. In the complex anion each Fe atom is tetrahedrally coordinated by three chlorine atoms and the oxo bridge. The magnetic properties have been investigated in the 4.2-300 K temperature range and these data correspond to the EPR spectra.

Full text of DOI:10.1016/S0277-5387(98)00094-1

Polyhedron Vol[ 06\ No[ 07\ pp[ 2070Ð2081\ 0887
Þ 0887 Elsevier Science Ltd
Pergamon
All rights reserved[ Printed in Great Britain
9166Ð4276:87 ,08[99¦9[99
\
PII] S9166Ð4276"87#99983Ð0
Synthesis\ structure\ spectra and magnetic
properties of the unsymmetrical oxo!bridged
complex
ðFe1O"OAsPh2#3Cl2Ł1ðFe1OCl5Ł[1CH2CN
Iveta Ondrejkovicova\a\ꢁ Tadeus Lis\b Jerzy Mrozinski\b Vlasta Vancovaa and
³
ꢀ
ꢀ
³
ꢀ
Milan Meln(ka
ꢀ
aDepartment of Inorganic Chemistry\ Slovak Technical University\ 701 26 Bratislava\ Slovakia
bFaculty of Chemistry\ Wroc<aw University\ 49!272 Wroc<aw\ Poland
"Received 19 October 0886^ accepted 15 February 0887#
Abstract*A new unsymmetrical "m!oxo#diiron"III# complex ðFe1O"OAsPh2#3Cl2Ł1ðFe1OCl5Ł[1CH2CN "I#\ where
OAsPh2 is triphenylarsine oxide\ has been prepared by several ways and characterized by X!ray structural
analysis\ elemental analysis\ spectral and magnetic methods[ The complex "I# is formed simultaneously with
another two complexes of the composition ðFe1O"OAsPh2#3Cl2ŁðFeCl3Ł[CH2CN "II# and ðFe"OAsPh2#3Cl1Ł
ð FeCl3Ł "III#[ In compound "I# the complex cation has one Fe atom coordinated by four OAsPh2 which form
a plane\ and the oxo!bridged ligand occupies an apex and form a square pyramid con_guration about the
second iron atom[ In the complex anion each Fe atom is tetrahedrally coordinated by three chlorine atoms
and the oxo bridge[ The magnetic properties have been investigated in the 3[1Ð299 K temperature range and
these data correspond to the EPR spectra[ Þ 0887 Elsevier Science Ltd[ All rights reserved
Keywords] iron"III# complexes^ unsymmetrical oxo!bridged complexes^ triphenylarsine oxide^ magnetism^ spec!
troscopic data^ structure[
———————————————————————————————————————————————
We are interested in the formation of iron complexes the presence of some iron salts and corresponding
with triphenylphosphine oxide "OPPh2# by auto! anions ð0Ð4Ł[ In spite of the simplicity of the PPh2!
catalytic oxidation of PPh2 by dioxygen to OPPh2 in system we have explored the AsPh2!system\ too[ How!
ꢁ Author to whom correspondence should be addressed[
Abbreviations] acac] acetylacetonate^ acacen] N\N?!ethylenebis"acetylacetonylideneiminate#^ bpy] 1\1?!bipyridine^ Bz] ben!
zyl^ cbpN] 1!hydroxy!4!chlorobenzophenone with 0\4\8! triazanonane^ C5H04N2] 0\3\6!triazacyclononane^ Cl!dipic] 3!chloro!
1\5!pyridinedicarboxylate^ dbat] 6\ 05!dihydro!5\ 7\ 05\ 06!tetramethyldibenzoðb\iŁð0\3\7\00Ł tetraazacyclotetradecinate^
dmso] dimethylsulfoxide^ dsit] S!methyl!N0\N3!di"salicyliden#isothiosemikarbazidate!S\N0\N3^ Fe"cp#1] ferrocenium^ hbpz2]
hydrotris!0!pyrazolylborate^ hfacac] hexa~uoroacetylacetonate^ hp] hemiporphyrazinate^ Me] methyl^ 1!Mequin] 1!methyl!
7!hydroxyquinolinate^ mim] 0!methylimidazole^ n4] N!"hydroxyethyl#!N\N?\N?!tris"1!benzimi!dazolylmethyl#!0\1!diam!
inoethane^ n5] N\N\N?\N?!tetrakis""1!benzimidazolyl#methyl#ethanediamine] N!n!propyl!sal] N!n!propylsalicylideneiminate^
N!p!Cl!Ph!sal] N!p!chlorophenylsalicylaldiminate^ nta] nitrilotriacetate^ odm] 4\04!dimethyl!1\2\6\7\01\02\06\07!octa!
ethylporphinate^ o!xy] o!xylene^ pc] phthalocyaninate^ phen] 0\09!phenanthroline^ py] pyridine^ salen] 0\1!bis"sali!
cylideneaminato#ethane"1!#^ taab] tetrabenzoðb\f\j\nŁð0\4\8\02Ł tetraazacyclohexadecane^ 2!tBusaltmen] 1\2!dimethyl!1\2!
bis"2!tert!butylsalicylideneamino#butane"1!#^ tetren] tetraethylenepentaamine^ tpa] tris"1!pyridylmethyl#amine^ tmpyp]
tetrakis"0!methylpyridinium!3!yl# porphyrinate"1!#^ tpc] 6\7!dihydroxo!4\09\04\19!tetraphenylporphyrinate^ tpp] 4\09\04\ 19!
tetraphenylporphyrinate"1!#^ tpp"F4#] 4\09\04\19!tetrakis!penta~uorophenylporphinate"1!#[
2070

2071
I[ Ondrejkovicova et al[
³ ꢀ
ever\ in the later case we have found that besides the 2[ ðFe"OAsPh2#3Cl1ŁðFeCl3Ł "III# as the most soluble
monomeric Fe"III# complex there are also formed the
diiron"III# complexes[ The monomeric ðFe"OAs!
Ph2#3Cl1ŁðFeCl3Ł salt is known which was prepared by
direct reaction of FeCl2 with OAsPh2 in ethanol ð5Ł
or toluene under anaerobic conditions ð6Ł[ Two oxo!
bridged diiron salts] ðFe1O"OAsPh2#3Cl2Ł1ðFe1O!
complex "light yellow plates#[ Found] C\ 42[47^ H\
2[67^ Cl\ 02[30^ Fe\ 5[56[ Calc[ for C61H59O3As3!
Cl5Fe1] C\ 42[59^ H\ 2[64^ Cl\ 02[07^ Fe\ 5[81)[
When the reaction mixture is kept under argon\ the
complex "III# is a major fraction[ However\ when the
raw product is slowly recrystallized from hot CH2CN
in the presence of O1\ both dimeric complexes "I¦II#
are formed in larger amounts[
Cl5Ł[1CH2CN
"I#
and
ðFe1O"OAsPh2#3Cl2Ł
ð FeCl3Ł[CH2CN "II# have di}erent anions[ The ð"OAs!
Ph2#3FeOFeCl2Ł¦ cation is the _rst nonbiological
unsymmetrical oxo!bridged Fe"III# complex ion with
penta! and tetracoordinated iron atoms[ However\
until to!date\ in all the known oxo!bridged Fe"III#
complexes both Fe"III# atoms are tetracoordinated
ð7Ð19Ł\ pentacoordinated ð10Ð26Ł\ hexacoordinated
ð27Ð37Ł or even heptacoordinated ð38Ł[ There are
examples ð49Ð42Ł\ in which two non!equivalent Fe"III#
atoms\ "viz[ hexa! and tetra! coordinated# are bridged
by a single O atom[ It is known ð43Ł that unsym!
metrical FeÐOÐFe bridge angle is present in a class of
dinuclear iron proteins[ The "m!oxo#!diiron"III# com!
plexes have been prepared by several ways and are
characterized by spectral and magnetic methods as
well as by X!ray analysis[ "The compound "II# has
been characterized by us previously ð44Ł#[
Method 1
Solutions of acetonitrile "ca[ 29 ml# and 9[69 ml of a
25) solution "by weight# of aqueous HCl "7[9 mmol#
"Tꢂ222 K# containing excess iron powder "9[22 g\
4[8 mmol# and AsPh2 "0[12 g\ 3[9 mmol# were stirred
for about 1 days under a dioxygen atmosphere[ The
completion of the oxidation of AsPh2 to OAsPh2 was
ascertained by comparing the electronic absorption
spectrum of the reaction solution with the spectrum
of pure OAsPh2 which exhibits four absorption bands
with the maxima at 141\ 148\ 151 and 169 nm[ The
resulting mixture was _ltered "mainly from Fe1O2# and
separated by fractional crystallization using CH2CN
by the same procedure of Method 0[ In this case com!
plex "III# was a minor fraction[ Both dimeric com!
plexes were obtained in equally amounts[
EXPERIMENTAL
Preparations of the compounds
Method 2
Complexes of the composition\ ðFe1O"OAs!
Ph2#3Cl2Ł1ðFe1OCl5Ł[1CH2CN "I# ðFe1O"OAsPh2#3Cl2Ł
ðFeCl3Ł[ CH2CN "II# and ðFe"OAsPh2#3Cl2ŁðFeCl3Ł "III#
are formed simultaneously and amounts of the indi!
vidual complexes are dependent on the reaction con!
ditions[ These complexes were prepared by several
ways]
AsPh2 "9[50 g\ 1[9 mmol# dissolved in ca[ 39 ml
CH2CN was transfered to FeCl2 "9[06 g\ 0[9 mmol#
in the reaction vessel[ The contents were stirred and
heated to a temperature of ½222 K under a O1 atmo!
sphere for ca[ 1 days[ Monitoring of the reaction
course and fractional crystallization were done in the
manner as mentioned above[ In this case the dimers
were obtained in larger amounts than complex "III#
and were suitable for X!ray analyses[
Method 0
Solution of OAsPh2 "1[464 g\ 7[9 mmol# in ethanol
"ca[ 69 ml# or toluene "ca[ 099 ml# was added to FeCl2
"9[537 g\ 3[9 mmol# at room temperature and the
resulting mixture stirred for 1 h[ The yellow product
which precipitated was _ltered out and recrystallized
from acetonitrile[ The individual complexes were sep!
arated by fractional crystallization using acetonitrile\
yielding the following three products^
Method 3
Fe1"SO3#2[6H1O "0[09 g\ 1[0 mmol# and KCl "9[59 g\
7[9 mmol# were placed into a thermostated vessel\ the
acetonitrile solution "ca[ 29 ml# of AsPh2 "0[12 g\
3[9 mmol# was added and the mixture was stirred
under O1 for about 1 days[ The course on this reaction
was monitored according to the manner mentioned
above[ After the oxidation\ the K1SO3 as a by!product
was _ltered out[ The crude product was separated by
fractional crystallization\ too[ The complex "II# was
the major product[
0[ ðFe1O"OAsPh2#3Cl2Ł1ðFe1OCl5Ł[1CH2CN "I# as the
least soluble complex "dark yellow sticks#[ Found]
C\ 40[45^ H\ 2[59^ Cl\ 01[89^ Fe\ 8[54[ Calcd[ for
C037H015As7Cl01Fe5N1O00] C\ 40[2^ H\ 2[6^ Cl\ 01[2^
Fe\ 8[6)[
1[ ðFe1O"OAsPh2#3Cl2ŁðFeCl3Ł[CH2CN "II# as more
soluble complex "yellow needles#[ Found] C\ 49[65^ Method 4
H\ 2[48^ N\ 9[72^ Cl\ 03[11^ Fe\ 8[35[ Calcd[ for
C63H52As3Cl6Fe2NO4] C\ 49[34^ H\ 2[59^ N\ 9[79^
Cl\ 03[98^ Fe\ 8[40)[
The acetonitrile solution "29 ml# of complex "III#
"9[30 g\ 9[14 mmol# was stirred for about 09 h under

Synthesis\ structure\ spectra and magnetic properties
2072
Table 0[ Crystal and structure re_nement data for
ð"Ph2AsO#3FeOFeCl2Ł1ðFe1OCl5Ł[1CH2CN "I#
O1 in a thermostated vessel "Tꢂ212 K#[ The dark!
yellow solution containing all the complexes was sep!
arated by fractional crystallization "see Method 0#[
The amount of "II# was larger than that of "I#[
Elemental analyses con_rm the composition of the
separated complexes "Method 1 to 4#[ Elemental
Formula
C037H015As7Cl01Fe5N1O00
Mr
2357[3
Crystallographic system
triclinic
02[412"00#
02[507"01#
13[998"04#
65[06"6#
76[82"6#
48[42"8#
2570"6#
0639
Ä
a "A#
analyses were carried out using
C\H\N\S!O "EA 0097# analyser[
a Carlo!Erba
Ä
b "A#
Ä
c "A#
a ">#
b ">#
g ">#
Spectroscopic studies
2
Ä
V "A #
F"999#
Space group
Z
Infrared spectra were recorded using Philips Ana!
lytical PU 8799 FTIR spectrometer in Nujol mulls
on KBr plates over 3999Ð199 cm−0 range[ Electronic
spectra were recorded on Specord M 39 spec!
trophotometer by Carl Zeiss[ Resonance Raman spec!
tra were recorded on a Bruker ER 199 E!SRC
spectrometer[ Electron paramagnetic resonance
"EPR# spectrum was measured with X!band Radi!
opan SE:X spectrometer for powder[ Solid sample of
Mn"II# in MgO was used as the reference and the
magnetic _eld was calibrated with a nuclear mag!
netometer MJ 009R[
P0
0
T "K#
019"1#
Ä
l "A#
9[60958
0[454"3#
0[358
rcalcd[ "g cm−2
#
#
rmeas[ "g cm−2
m "cm−0
#
15[3
No[ of re~cns collcd[
8903
No[ of obsd[ re~cns
5589"I ×2s#
9[9260
R "ꢂS>Fo=−=Fc>:S=Fo=
wR1
w
9[9874
0:ð"s1"F1o#¦9[956P#1¦09[3P
Ma`netic measurements
Magnetic susceptibility of the polycrystalline sam!
ples of the compounds were measured by the Faraday
method in the temperature range 3[1Ð182 K\ using a
sensitive Sartorius M!14D electrobalance[ Sus!
ceptometer was equipped with Oxford Instruments
CF!0199 continuous!~ow cryostat and an elec!
tromagnet operating at 5[14 kG[ The calibrant
employed was HgCo"NCS#3 ð45Ł\ for which the mag!
netic susceptibility taken as 05[33×09−5 cm2 g−0[ The
correction for diamagnetism of the constituent atoms
was calculated using Pascal|s constants ð46Ł and found
to be −817×09−5 cm2 mol−0 and −0719×09−5 cm2
mol−0 per molecule of complexes I and II\ respectively[
The value Naꢂ9 "cm2 mol−0# was used for the tem!
perature independent paramagnetism of the
compounds[ The e}ective magnetic moment was cal!
culated from the equation\ meffꢂ1[72×"xM×T#0:1
"B[M[#[ The value of the exchange parameters
were determined by least!square procedure\ and the
minimization of the function]
collection "3> ³ 1U ³ 33># "Table 0#[ Standard inert
atmosphere techniques were used[ A systematic search
of a limited hemisphere of reciprocal space located no
symmetry or systematic absences indicating a triclinic
space group[ Subsequent solution and re_nement of
the structure con_rmed the proper space group to be
P0[ The structure was solved by direct methods and
re_ned by SHELXL!82 program ð47Ł[ The phenyl ring
H!atoms were included in geometrically calculated
positions and the acetonitrile H!atoms were not deter!
mined from _nal di}erence map[ No absorption cor!
rection was applied[ A _nal di}erence map was
essentially featureless\ the largest peaks being in the
vicinity of the As atoms[ The high values of aniso!
tropic temperature factors for acetonitrile molecules
may suggest partially disorder of these molecules[
Bond lengths and angles\ atomic coordinates\ dis!
placement parameters and lists of structure factors for
"I# are deposited[
n
Rꢀ s "xiexp t0−xicalcd#1:"xiexp t0
#
1
RESULTS AND DISCUSSION
iꢀ0
Anhydrous FeCl2 and OAsPh2 interact rapidly in
several solvents "e[g[ ethanol ð5Ł\ toluene ð6Ł\ ace!
tonitrile# to a}ord yellow solutions[ When the inter!
action is carried out under anaerobic conditions\ the
complex "III# is formed as a major product[ However\
was the criterion used to determine the best _t[
X!ray structure determination
ðFe1O"OAsPh2#3Cl2Ł1ðFe1OCl5Ł[1CH2CN "I# A well! in the presence of oxygen the I and II complexes are
formed dark yellow crystal was a.xed to the end of also formed\ "Method 0#[ A similar mixture of these
glass _ber using silicone grease and transferred to 2 complexes were also obtained when the following
the goniostat where it was cooled to 019 K for data reactants were used as the starting compounds]

2073
I[ Ondrejkovicova et al[
³ ꢀ
Ä
Table 1[ Selected bond lengths "A#\ bond angles "># and
torsion angles "># for ð"Ph2AsO#3FeOFeCl2Ł¦ in "I#[
FeÐHClÐAsPh2ÐO1
FeCl2ÐAsPh2ÐO1
Fe1"SO3#2[6H1OÐKClÐAsPh2ÐO1
ðFe"OAsPh2#3Cl1ŁðFeCl3ŁÐO1
"Method 1#
"Method 2#
"Method 3#
"Method 4#
Fe"0#[[[Fe"1#
Fe"0#ÐO"0#
2[432"2#
0[861"3#
0[863"3#
0[882"4#
1[991"4#
0[668"3#
0[665"3#
1[112"3#
1[102"1#
1[108"2#
0[571"3#
0[580"3#
0[579"3#
0[564"3#
Autocatalytic oxidation of AsPh2 to OAsPh2 by O1\ Fe"0#ÐO"1#
Fe"0#ÐO"2#
Fe"0#ÐO"3#
Fe"0#ÐO"4#
Fe"1#ÐO"4#
Fe"1#ÐCl"0#
Fe"1#ÐCl"1#
Fe"1#ÐCl"2#
As"0#ÐO"0#
As"1#ÐO"1#
As"2#ÐO"2#
which has taken place in the Methods 1\ 2 and 3\ were
used for the preparation of mainly diiron complexes[
During oxidation of AsPh2 mentioned reaction sys!
tems consumed O1\ what was demonstrated by
measurements of dioxygen uptake on the apparatus
described previously ð0Ł[
Both the complexes "I# and "II# are built with ident!
ical cationic forms "Fig[ 0#\ di}erent anions "FeCl3−
ð44Ł and Fe1OCl15− "Fig[ 1## and acetonitrile solvate
molecules[ Selected bond distances and angles of the As"3#ÐO"3#
complex "I# are given in Tables 1 and 2\ respectively[
As"0#ÐO"0#ÐFe"0#
025[5"2#
The complex cations of "I# and "II# have similar struc!
tures[ They contain two unsymmetrical iron"III# m!
oxo species "Fig[ 0#[ The Fe"0# atom is coordinated by
four OAsPh2 ligands which form a distorted square
pyramide con_guration about the Fe"0#[ The Fe"1# is
tetrahedrally coordinated by three chlorine atoms and
the oxo bridge[ They di}er signi_cantly with FeÐOÐ
Fe bond angle of 050[9"2#> in "II# and of 069[2"2#> in
As"1#ÐO"1#ÐFe"0#
As"2#ÐO"2#ÐFe"0#
As"3#ÐO"3#ÐFe"0#
O"0#ÐFe"0#ÐO"4#
O"1#ÐFe"0#ÐO"4#
O"2#ÐFe"0#ÐO"4#
O"3#ÐFe"0#ÐO"4#
O"0#ÐFe"0#ÐO"1#
018[6"2#
022[5"2#
027[1"2#
094[0"1#
095[4"1#
092[3"1#
094[1"1#
037[3"1#
76[8"1#
Ä
"I#[ The Fe"1#ÐO"4# bonds of 0[648"3# A in "II# and O"0#ÐFe"0#ÐO"2#
Ä
O"0#ÐFe"0#ÐO"3#
O"1#ÐFe"0#ÐO"2#
O"1#ÐFe"0#ÐO"3#
O"2#ÐFe"0#ÐO"3#
Fe"0#ÐO"4#ÐFe"1#
O"4#ÐFe"1#ÐCl"0#
O"4#ÐFe"1#ÐCl"1#
O"4#ÐFe"1#ÐCl"2#
Cl"0#ÐFe"1#ÐCl"1#
Cl"0#ÐFe"1#ÐCl"2#
76[9"1#
73[7"1#
73[8"1#
0[665"3# A in "I# are slightly shorter than the Fe"0#Ð
Ä
Ä
O"4# bonds "0[673"3# A in "II# and 0[668"3# A in "I##\
as expected[ Both lengths\ as well as the FeÐOÐFe
angle\ fall in the range of values observed for the
diiron"III# m!oxo analogues "Table 4#[ The bond
040[3"1#
069[2"2#
009[5"1#
000[1"1#
001[1"1#
094[3"1#
095[2"1#
009[8"1#
Ä
lengths for Fe"1#ÐCl in "II# "average 1[193"2# A# are
identical with those observed in the ð"n4#FeOFeCl2Ł¦
Ä
cation "average 1[192"2# A# ð41Ł and they are the
slightly shorter than Fe"1#ÐCl bond lengths in "I#
Ä
"average 1[107"3# A#[ To our knowledge\ the FeÐ Cl"1#ÐFe"1#ÐCl"2#
Cl"0#ÐFe"1#ÐO"4#ÐFe"0#
04[7"04#
−099[8"04#
023[2"04#
−009[7"04#
58[0"04#
−08[4"04#
047[1"04#
83[5"3#
Cl"1#ÐFe"1#ÐO"4#ÐFe"0#
Cl"2#ÐFe"1#ÐO"4#ÐFe"0#
Fe"1#ÐO"4#ÐFe"0#ÐO"0#
Fe"1#ÐO"4#ÐFe"0#ÐO"1#
Fe"1#ÐO"4#ÐFe"0#ÐO"2#
Fe"1#ÐO"4#ÐFe"0#ÐO"3#
O"4#ÐFe"0#ÐO"0#ÐAs"0#
O"4#ÐFe"0#ÐO"1#ÐAs"2#
O"4#ÐFe"0#ÐO"2#ÐAs"2#
O"4#ÐFe"0#ÐO"3#ÐAs"3#
091[5"3#
093[5"3#
71[3"3#
"OAsPh2# fragment has not been characterized pre!
viously[
In "II# the Fe"2# atom in the ðFeCl3Ł− anion is tetra!
hedrally coordinated by four chlorine atoms "FeÐCl
Ä
Ä
range from 1[047"3# A to 1[079"2# A and ClÐFeÐCl
angles from 097[9 to 000[5"1#> what is typically for
these anions ð48Ł[
Fig[ 0[ The overall view of ð"OAsPh2#3FeOFeCl2Ł¦ cation in
"I#[
The iron atoms in the oxo!bridged dinuclear
ðCl2FeÐOÐFeCl2Ł1− anion in "I# each possess a slightly

Synthesis\ structure\ spectra and magnetic properties
2074
Fig[ 1[ The packing in the "I# crystal "approximately along the Fe[[[Fe axis#[
Ä
Table 2[ Selected bond lengths "A#\ bond angles "># and
Table 3 summarized infrared spectroscopic data of
three Fe"III#ÐOAsPh2 complexes[ In the IR spectra of
these complexes showed that n"AsÐO# bands are
shifted to lower energies compared with the free
OAsPh2\ as the result of OAsPh2 coordination[ The
dimeric complexes I and II have a strong new absorp!
tion at 738 cm−0 and 730 cm−0\ respectively[ It is attri!
buted to the asymmetric FeÐOÐFe stretching vibration
"nas#[ Intense absorption in the region 799Ð759 cm−0 is
commonly used as diagnostic criterion for identi!
_cation of the oxo!monobridged Fe"III# complexes ð7\
41Ł[ The bands assigned to the symmetric FeÐOÐFe
stretching vibration "ns# observed at 304 "I# and at
300 cm−0 "II# are within the range expected for these
monobridged structures ð59Ł[ The FeÐOÐFe vibrations
of I and II correlate with bond angles^ the FeÐOÐFe
angles can be predicted within 09> from knowledge of
ns and nas ð59Ł[ In the infrared spectrum the FeÐOÐFe
frequencies are nearly identical with those observed
in the Raman spectrum[ Whereas nas"FeÐOÐFe# are
torsion angles "># for Fe1OCl15− in "I#
Fe"2#[[[Fe"2i#
Fe"2#ÐCl"3#
Fe"2#ÐCl"4#
Fe"2#ÐCl"5#
Fe"2#ÐO"5#
2[401"2#
1[121"2#
1[197"2#
1[107"3#
0[645"1#
Cl"3#ÐFe"2#ÐCl"4#
Cl"3#ÐFe"2#ÐCl"5#
Cl"3#ÐFe"2#ÐO"5#
Cl"4#ÐFe"2#ÐCl"5#
Cl"4#ÐFe"2#ÐO"5#
Cl"5#ÐFe"2#ÐO"5#
097[4"1#
095[1"1#
001[4"1#
000[1"1#
098[1"1#
098[2"1#
Symmetry code] "I# 0−x\ 0−y\ −z[
distorted tetrahedral ligand environment[ The bond
distances of the anion agree with those of the com! stronger and ns"FeÐOÐFe# are weaker in the IR spectra
pounds investigated so far[ The FeÐOÐFe angle is of I and II\ in the Raman spetra the stretching
relatively large "Table 4#[
vibration intensities are opposite[ Infrared bands at

2075
I[ Ondrejkovicova et al[
³ ꢀ
Table 3[ Characteristic IR data "cm−0# for the Fe"III#ÐOAsPh2 complexes
Compound
n"AsÐO#
n"FeOFe#
n"FeCl−3 #
n"FeCl2#
nas
ns
nas
ns
III
II
I
758s 717s
759s 717s
770s 729vs
*
730s
738vs
*
300m
304m
279s
271s
*
*
258m
252vs
*
296m
203m
252 "I# and 258 cm−0 "II# are assigned to the respective
FeÐCl2 asymmetric stretch by comparison with
ðFe1OCl5Ł1− and bands at 203 "I# and 296 cm−0 "II# are
assigned similarly to the symmetric FeCl2 mode in
agreement with literature data ð40Ł[ IR spectra of II
and III show a characteristic strong band at 272 and
279 cm−0 "n2# of FeCl−3 \ respectively ð7Ł[
In Table 4 are summarized selected structural data
for m!oxo!bridged dimeric Fe"III# compounds[ As can
be seen\ the mean FeÐO"bridge# bond distance
increases with increasing coordination number in the
Ä
Ä
sequence] 0[643 A "tetra coordinated# ³0[660 A
Ä
"penta coordinated# ³0[675 A "hexa coordinated#\ as
Fig[ 2[ Plots of the magnetic susceptibility versus T for
Fe1OCl51− anions calculated for `ꢂ1\ Jꢂ −069 cm−0\ dia!
expected[ The FeÐOÐFe bridge angles in the series of
tetra!\ penta! and hexa!coordinated species are well
comparable\ i[e[ they are in the range of 036[6 to 079>\
of 031[6 to 079> and of 035[5 to 079>\ respectively[
There are relationships between the FeÐOÐFe bridge
angle and FeÐFe distances[ When the former closses
the latter is shortened[
magnetic correctionꢂ −077[ 09−5 cm2 mol−0
[
molar magnetic susceptibility and the magnetic
moment for both the complexes as a function of tem!
perature enables us to compare their properties "Fig[
3^ magnetic data are given for whole molecular
system[#[ Both the complexes indicate a relation typi!
cal for a paramagnet\ although the magnetic e}ect for
the complex "II# is stronger "Table 5#[
The anion FeCl−3 is a strong paramagnet with
Sꢂ4:1 spin\ but the Fe1OCl15− ion is a molecular
antiferromagnet[ Using the theoretical equation ð50Ł
N1`m1B
x
M ꢂ
kT
0 1
1e1x¦09e5x¦17e01x¦59e19x¦009e29x
In the EPR spectrum of the complex "II# only one
×
0¦2e1x¦4e5x¦6e01x¦8e19x¦00e29x
0
1
"where xM was corrected for diamagnetism\ and
TIPꢂ9 and xꢂJ:kT# and X! ray data "this work# for
Fe1OCl15− in the crystal lattice of the complex "I#\ the
1−
relation xFe OCl ꢂf"T# was prepared "Fig[ 2#[ The
magnetic in1teraction in a dimer is expressed by the
5
HeisenbergÐDiracÐvan
Vleck
Hamiltonian\
¼
¼
H
HDVVꢂ−1JS S \ where Sa and Sb are the spins of the
a
b
¼
¼
magnetically interacting iron"III# ions "SaꢂSbꢂ4:1#[
The cationic forms observed in both the complexes
indicate lack of any symmetry and a di}erence in the
bridging angle FeÐOÐFe\ 069[2> and 050[9> for the
complexes I and II\ respectively[
In the crystal lattice of the complex II two mag!
netically isolated paramagnetic forms exist\ which
con_rms the absence of the maximum on the exper!
imental curve xMꢂ f"T# up to 3[1 K[ A weak anomaly
observed in the region 3[1Ð19 K and the value
U½ −1[4 K may suggest weak antiferromagnetic
superexchange interaction[ The relation between
Fig[ 3[ Experimental magnetic susceptibility and magnetic
moment vs[ temperature for ð"OAsPh2#3FeOFeCl2ŁðFeCl3Ł
" ž \R# and ð"OAsPh2#3FeOFeCl2Ł1ðFe1OCl5Ł "o\e#\ respec!
tively[

Synthesis\ structure\ spectra and magnetic properties
2076
Table 4[ Selected structural data for m!oxo!bridged dimeric Fe"III# compoundsa
Ä
Ä
Complex
Chromophore
FeCl2O
FeÐL "A#
FeÐFe "A#
LÐFeÐL ">#
Ref[
FeÐOÐFe ">#
"Ph3P#1 ðFe1OCl5Ł
mO
Clb
mO
Cl
mO
Cl
mO
Cl
mO
Cl
mO
Cl
mO
Cl
mO
Cl
mO
Cl
mO
Cl
mO
Cl
mO
Cl
mO
Cl
mO
Cl
mO
Cl
mO
Cl
mO
Cl
0[633 "3\9#
1[109 "1\5#
0[639 "0#
1[100 "1\00#
0[659 "2\2#
1[105 "1\10#
0[655 "4\8#
1[109 "1\03#
0[644 "2\9#
1[103
not given
069[3 "3#
2[379
Cl\ Clb
mO\ Cl
Cl\ Cl
mO\ Cl
Cl\ Cl
mO\ Cl
Cl\ Cl
mO\ Cl
097[3 "1\0[4#
009[4 "1\0[4#
097[0 "0\7#
009[7 "0\1[5#
097[6 "0\1[4#
009[2 "1\1[1#
098[4 "0\0[7#
098[3 "1\0[4#
not given
ð7Ł
ð8Ł
"Ph3P#1 ðFe1OCl5Ł = 1CH1Cl1 FeCl2O
079[9
"BzPh2P#1ðFe1OCl5Ł
"BzPhMe1N#1ðFe1OCl5Ł
"Hpy#1ðFe1OCl5Ł = py
"Ph3As#1ðFe1OCl5Ł
FeCl2O
FeCl2O
FeCl2O
FeCl2O
FeCl2O
FeCl2O
FeCl2O
FeCl2O
FeCl2O
FeCl2O
2[356"1#
059[1 "4#
2[282"0#
036[6"2#
2[317"2#
044[5 "6#
2[358d
ð7Ł\ð09Ł
ð00Ł
ð7Ł\ð09Ł\ð01Ł
ð7Ł\ð02Ł
ð03Ł
0[63 "2#
1[196
not given
not given
not given
069[7 "4#
2[493
ð"Ph2P#1CSeŁ1ðFe1O!
Cl5Ł = 3CH1Cl1
"BzEt2N#1ðFe1OCl5Ł
0[641"1#
not given
0[644 "4\2#
1[108
079[9
not given
044[2 "2#
not given
049[2 "3#
2[390d
035[4 "1#
not given
038[6"3#
2[263d
041[6"3#
2[344"6#
050[5 "8#
2[263d
ð7Ł
ðFeCl"dmso#4ŁðFe1OCl5Ł
0[659 "7\5#
1[192 "3\00#
0[665 "4\1#
1[112 "1\8#
0[652 "6\9#
1[105"3\03#
0[626"6\5#
1[089"2\8#
0[64 "1\0#
1[11 "1\1#
0[641"00\01#
1[198"5\05#
0[654"2\0#
1[111"0\0[5#
0[638"3\9#
1[086"4\6#
0[645"1\9#
1[108"3\02#
Cl\ Cl
mO\ Cl
Cl\ Cl
mO\ Cl
Cl\ Cl
mO\ Cl
Cl\ Cl
mO\ Cl
Cl\ Cl
mO\ Cl
098[9 "1\0[4#
098[7"2\ 1[8#
098[2 "0\0[4#
098[4 "0\1[9#
098[1 "0\0[3#
098[6 "1\0[8#
097[7 "1\1[7#
009[9"2\1[7#
098[0 "1\1[9#
098[8 "4\2[2#
not given
ð04Ł
ðFeCl"dmso#4ŁðFe1OCl5Ł
"at 092 K#
ðFeCl"dmso#4ŁðFe1OCl5Ł
"at 112 K#
ðFeCl"dmso#4ŁðFe1OCl5Ł
"at 232 K#
ðFe"phen#2ŁðFe1OCl5Ł = dmf FeCl2O
ð04Ł
ð04Ł
ð04Ł
ð05Ł
ðFe"bpy#2ŁðFe1OCl5Ł
FeCl2O
FeCl2O
FeCl2O
ð06Ł
037[8"6#
ðFe"bpy#2ŁðFe1OCl5Ł
"at 112 K#
ðFe"cp#1Ł1ðFe1OCl5Ł
2[283d
Cl\ Cl
mO\ Cl
Cl\ Cl
mO\ Cl
Cl\ Cl
mO\ Cl
097[58"4\0[81#
009[1"09\0[9#
097[3"1\0[2#
009[4"3\4#
097[5"1\1[5#
009[2"1\1[1#
ð07Ł
037[0"1#
2[344"4#
051[0"4#
2[401"2#
079[99
ð08Ł
ðFe1O"OAsPh2#3Cl2Ł1Ð
ðFe1OCl5Ł = 1MeCN
"at 019 K#
FeCl2O
"anion#
this work
ðFe"cp#1Ł1ðFe1OBr5Ł
FeBr2O
mO
Br
O
mO
N
0[641"1\9#
1[236"3\6#
0[814"03\04#
0[670"00\10#
1[073"03\3#
not given
048[7"3#
2[340d
Br\ Br
mO\ Br
O\ O
mO\ O
N\ N
097[7"0\1[3#
009[1"3\0[2#
012[3"5#
007[2"4\4#
059[8"4#
ð19Ł
ð10Ł
ðFe1O"1!Mequin#3Ł = CHCl2 FeO2N1
040[5"6#
O\ N
mO\ N
68[2"4\0[2#
80[7"4\1[0#
88[3"4\0#
ðFe1O"N!p!ClPh!sal#3Ł
FeO2N1
O
mO
N
0[78"1\2#
0[66"0\0#
1[05"1\4#
2[42
064"0#
O\ O
016[0"6\1[5#
005[3"6\2[9#
057[5"6\0[0#
76[6"6\2[4#
84[6"6\1[2#
003"1\2#
75"0\0#
87"1\3#
76[5"2\1#
ð11Ł
mO\ O
N\ N
O\ N
mO\ N
mO\ O
O\ N
mO\ N
O\ O
mO\ O
N\ N
O\ N
ðFe1O"N!n!propyl!sal#3Ł
ðFe1O"acacen#1Ł = CH1Cl1
FeO2N1
FeO2N1
O
mO
N
O
mO
N
0[82"1\0#
0[66"0\0#
1[03"1\0#
0[851"7\6#
0[672"6\03#
1[966"8\18#
not given
053"4#
ð12Ł
ð13Ł
c
not given
043[5"3#
097[5"3\1[5#
68[0"3\0[1#
76[9"3\7#
mO\ N
034[6"3\4[5#
094[1"3\2[9#
continued

2077
I[ Ondrejkovicova et al[
³ ꢀ
Table 4*continued[
Ä
Ä
Complex
Chromophore
FeO2N1
FeÐL "A#
FeÐFe "A#
LÐFeÐL ">#
Ref[
ð13Ł
FeÐOÐFe ">#
c
ðFe1O"acacen#1Ł = CH1Cl1
O
mO
N
0[844"7\4#
0[679"6\4#
1[979"8\07#
not given
044[5"4#
O\ O
77[4"2\7#
098[2"3\2[7#
68[0"3\5#
mO\ O
N\ N
O\ N
mO\ N
75[4"3\5#
034[3"3\4[7#
093[5"3\1[8#
098[5"4\1[2#
74[3"4\2#
034[3"4\3[6#
092[2"4\2[9#
84"3#
ðFe1O"salen#1Ł = 1py
FeO2N1
O
mO
N
0[81"0\1#
0[67"0\9#
1[01"1\0#
2[280
033[5"5#
mO\ O
O\ N
mO\ N
ð14Ł
ðFe1O"salen#1Ł = CH1Cl1
ðFe1O"2!tBusaltmen#1Ł
FeO2N1
FeO2N1
O
mO
N
O
mO
N
0[83"2\9#
0[79"4\9#
1[01"2\0#
0[812"3\7#
0[668"3\4#
1[013"4\08#
not given
033"1#
O\ O
N\ N
O\ N
O\ O
N\ N
O\ N
ð15Ł
ð16Ł
65"3#
75"3\0#
2[440
81[38"08\04#
64[79"11\1#
74[09"08\67#
025[91"07\0[79#
038[91"08\0[97#
82[2"1\3#
062[34"16#
ðFe1O"dsit#1Ł = 1H1O
ðFe1O"dbat#1Ł = MeCN
ðFe1O"tpp#1Ł
FeO2N1
FeN3O
FeN3O
O
mO
N
mO
N
0[801"3\09#
0[658"2\9#
1[093"4\2#
0[681"0\0#
1[942"1\00#
2[370"3#
045[3"1#
O\ O
N\ N
O\ N
N\ N
mO\ N
ð17Ł
ð18Ł
ð29Ł
61[5"1\1#
75[1"1\0[6#
72[21"6\4[25#
039[08"6\0[90#
098[80"6\0[40#
75[7 "2\3#
041[4 "1\0[3#
092[6 "1\3[9#
75[8"3\9#
2[286d
031[64"8#
mO
N
0[652 "0#
1[976 "5\00#
not given
063[4"0#
N\ N
N\ N
mO\ N
N\ N
ðFe1O"tpp#1Ł "at 011 K#
FeN3O
FeN3O
FeN3O
mO
N
mO
N
0[648"0\9#
1[970"2\9#
0[656"3#
1[956"5\01#
0[639"3#
2[405d
ð20Ł
ð21Ł
065[0"1#
not given
054[3"2#
042"1\9#
76[3 "1\8#
ðFe1O"NCH2tpp#"tpp#Ł!
ClO3 "at 022 K#
N\ N
mO\ N
N\ N
044[3"1\0[3#
091[2"1\1[5#
75[0"1\1[3#
038[6"1\3#
094[9"1\4[4#
75[7"1\2#
041[4"2\2[4#
092[6"0\0[7#
75[4"1\1[7#
093[3"1\0[5#
76[1"3\3#
mO
MeN 1[146"4#
mO\ N
N
1[947"5\7#
ðFe1O"tpc#1Ł 3CHCl2
"at 032 K#
FeN3O
mO
N
0[644"4\7#
1[973"4\07#
2[409"7#
079
N\ N
mO\ N
ð22Ł
ðFe1O"odm#1Ł
FeN3O
FeN3O
mO
N
mO
N
0[641"0#
1[954"3\01#
0[649"1#
2[493d
N\ N
mO\ N
N\ N
ð23Ł
ð24Ł
067[4"5#
not given
064[0"6#
ðFe1O"tmpyp#1Ł!
"ClO3#7 = 3H1O
"at 007 K#
1[970"8\04#
mO\ N
043[1"3\1#
091[1"3\0[1#
094[0"2\0[5#
ðFe1O"tpp"F4##1Ł "at 062 K# FeN3O
mO
N
mO
N
0[664"0\9#
1[977"6\05#
0[666"3\5#
1[953"4\57#
2[449
mO\ N
ð25Ł
ð26Ł
067[3"4#
2[441"0#
065[2"2#
ðFe1O"taab#1"MeO#3Ł
FeN3O
FeO4N
N\ N
mO\ N
77[6"1\2[2#
82[1"1\1[4#
004[5"1\3[3#
78[2"0\5#
038[0"0\2#
064[0"0\1#
87[8"0\5[5#
70[0"0\5[5#
079
ðFe1O"Cl!dipic#1"H1O#3Ł
= 3H1O
O
mO
N
1[964"2\11#
0[662"2\0#
1[094"2\2#
2[434"0#
079
O\ O
mO\ O
O\ N
ð27Ł
mO\ N
BaðFe1O"nta#1"H1O#1Ł
= 3H1O
FeO4N
O
mO
N
1[94"0\03#
0[71"0\0#
1[12"0\9#
not given
042[1"5#
mO\ O
O\ N
092[4"4#
67[0"3#
ð28Ł
continued

Synthesis\ structure\ spectra and magnetic properties
2078
Table 4*continued[
Ä
Ä
Complex
Chromophore
FeO3N1
FeÐL "A#
FeÐFe "A#
LÐFeÐL ">#
Ref[
ð39Ł
FeÐOÐFe ">#
ðFe1O"phen#1"H1O#5ŁÐ
"NO2#3 = 3H1O
O
mO
N
1[957"4\75#
0[664"3\09#
1[044"5\01#
2[495"1#
051[9"2#
O\ O
mO\ O
75[8"1\8[6#
83[5"1\0[8#
064[6"1\0[1#
65[7"1\3#
78[2"1\3[5#
053[7"1\1[0#
86[3"1\1[5#
88[6"0\4[9#
88[8"0#
70[1"0\6[3#
74[6"0\2[8#
051[7"0\1[1#
83[3"0\3[4#
055[9"0#
N\ N
O\ N
mO\ N
O\ O
mO\ O
N\ N
O\ N
ðFe1O"MeC"CH1NCMeÐ FeO2N2
CH1C"CF2#1##1"CH1NH1#1Ł
O
mO
N
0[861"1\19#
0[700"0#
1[120"2\71#
2[357"0#
035[5"1#
ð30Ł
mO\ N
ðFe1O"cbpN#1Ł = 2o!xy
FeO2N2
mO
O
N
mO
N
0[795"2\1#
not given
2[339d
033[4"1#
not given
ð31Ł
ð32Ł
ðFe1O"C5H04N2#1#"acac#1ŁÐ FeO2N2O
"ClO3#1
1[996"4\00#
0[676"4\4#
1[067"6\40#
2[401"1#
047[5"2#
O\ O
mO\ O
N\ N
O\ N
78[0"1\1#
87[8"1\0[1#
67[9"2\0[6#
89[4"2\5[6#
052[6"2\1[2#
85[1"2\3[0#
069[4"1\7#
not given
mO\ N
ðFe1O"hbpz2#"hfacac#1Ł
ðFe1O"tetren#1ŁI3
FeO2N2
FeN4O
O
mO
N
mO
N
1[960"6\01#
0[665"6\1#
1[016"8\71#
0[66"0\9#
2[426"1#
058[3"3#
ð33Ł
ð34Ł
2[420d
061
N\N
62"0\0#
70"0\0#
1[14"4\02#
80"3\1#
099"3\1#
059"1\8#
mO\ N
044"1#
092"4\5#
77"0#
ðFe1O"pc#1#"mim#1ŁÐ
ðFe"pc#"mim#1Ł = 2Me1CO
FeN4O
mO
pcN
0[638"0\9#
0[811"7\16#
not given
064[0
N\N
78[5"3\1[9#
067[2"3\0[9#
89[7"2\0[1#
067[8"3#
71[4"2\7[3#
047[1"2\8#
85[3"2\4#
80[9"2\6[5#
053[0"1\0[6#
87[4"2\3[1#
061[4"2\0[9#
68[7"2\7[0#
040[8"2#
82[3"2\0[1#
069[5"1#
87[6"1\7[7#
054[1"1#
88[2"0#
47[38"6\41#
64[98"6#
ð35Ł
ð36Ł
imN 1[928"6\9#
mO\ N
N\N
ðFe1O"phen#3"H1O#1ŁÐ
"NO 2#3 = 4H1O
FeN3O1
mO
O
N
0[674"4\1#
1[913"8\2#
1[064"8\77#
2[38
044[0"3#
mO\ O
O\N
mO\ N
N\N
ðFe1O"tpa#1Cl1Ł"ClO3#1
FeN3OCl
mO
N
Cl
0[674"0\9#
1[081"6\43#
1[187"1#
2[454"1#
063[6"4#
ð37Ł
ð38Ł
mO\ N
N\Cl
mO\ Cl
O\ O
ðFe1O"NO2#3"bpy#1Ł
"at 190 K#
FeO4N1
O
mO
N
1[080"1\69#
0[6644"3#
1[048"1\08#
2[4409"6#
079
mO\ O
N\N
83[80"5\2[65#
64[91"7#
O\N
mO\ N
72[27"7\2[43#
84[20"5#
058[08"5#
continued

2089
I[ Ondrejkovicova et al[
³ ꢀ
Table 4*continued[
Ä
Ä
Complex
Chromophore
FeÐL "A#
FeÐFe "A#
LÐFeÐL ">#
Ref[
ð44Ł
FeÐOÐFe ">#
ðFe1O"OAsPh2#3Cl2ŁÐ
ðFeCl3Ł = MeCN
FeCl2O
FeO4
Cl
mO
O
1[193"2\03#
0[648"3#
0[865"3\10#
0[673"3#
2[383"2#
050[9"2#
Cl\ Cl
mO\ Cl
O\ O
097[3"1\1[3#
009[4"1\8#
75[1"1\8#
mO
mO\ O
049[0"2\2[4#
094[9"1\1[3#
096[4"1\2[3#
000[2"1\8#
75[1"1\0[6#
038[8"1\0[4#
094[0"1\0[6#
098[9"1\5#
098[8"2\0[2#
66[8"2#
ðFe1O"OAsPh2#3Cl2Ł1Ð
ðFe1OCl5Ł = 1MeCN
"at 019 K#
FeCl2O
Cl
mO
O
1[107"3\4#
0[665"3#
0[874"4\06#
0[668"3#
2[432"2#
069[2"2#
Cl\ Cl
mO\ Cl
O\ O
this work
ð49Ł
FeO4
"cation #
mO
mO\ O
Cl\ Cl
mO\ Cl
aN\aN
iN\ iN
ðFe1O"n5#Cl2ŁCl = 9[4Ð
HCl = 2H1O = 1EtOH
FeCl2O
FeN4O
Cl
1[190"3\02#
0[634"6#
1[21"0\3#
1[97"0\2#
0[680"6#
2[339"1#
042[1"3#
mO
aN
iN
82[4"3\2[7#
051[3"2#
mO
aN\ iN
72[9"2\4[6#
041[6"2#
iN\ mO
88[4"2\4[1#
aN\ mO 090[2"2#
061[6"2#
ðFe1O"n4#Cl2ŁCl = 1EtOH
FeCl2O
FeN4O
Cl
1[192"2\4#
0[640"3#
1[219"4\26#
1[984"5\08#
0[673"3#
2[300"0#
038[4"2#
Cl\ Cl
mO\ Cl
aN\ aN 67[9"1#
iN\ iN
aN\ iN
iN\ mO
009[0"0\1[4#
097[7"1\1[3#
ð40Ł ð41Ł
mO
aN
iN
80[8"1\1[4#
051[9"1#
70[1"1\7[6#
038[4"1#
090[3"1\6[4#
mO
aN\ mO 099[5"1#
061[5"1#
ðFe1O"n4#Br2ŁBr = 1EtOH FeBr2O
FeN4O
Br
1[237"2\08#
0[615"8#
1[20"0\2#
1[98"0\1#
0[686"8#
2[397"2#
049[5"3#
Br\ Br
mO\ Br
aN\ aN 67[1"3#
iN\ iN
aN\ iN
iN\ mO
098[7"0\1[9#
098[0"2\2[1#
ð41Ł
mO
aN
iN
81[9"3\1[2#
051[0"3#
70[1"3\6[6#
049[0"3#
090[2"3\6[2#
mO
aN\ mO 099[5"3#
061[6"2#
ðFe1O"hp#1"H1O#Ł
FeN3O
N
0[875"09\4#
1[082"00\02#
0[628"5#
2[41
079
N\ N
76[8"2\3#
037[5"3#
053[5"3#
ð42Ł
mO
mO\ N
N\ N
090[6"2\3[9#
78[7"3\0#
060[8"3\0[4#
83[0"2\6#
74[8"2\6#
FeN3O1
N
O
1[987"00\097#
1[101"5#
mO
0[671"5#
O\ N
mO\ N
a Where more than one chemically equivalent distance or angle present\ the mean value is tabulated[ The _rst number in
parenthesis is e[s[d[\ the second is maximum deviation from the mean value[
b The chemical identity of coordinated atom:ligand is speci_ed in these columns[
c There are two crystallographically independent molecules[
d It indicates that the distance was calculated trigonometrically ð59Ł[

Synthesis\ structure\ spectra and magnetic properties
Table 5[ Magnetic data
2080
Compound
Temperature
Magnetic susceptibility Magnetic
T"K#
xM×095 "cm2 mol−0
#
moment
me} "B[M[#
ðFe1O"OAsPh2#3Cl2ŁðFeCl3Ł[CH2CN
ðFe1O"OAsPh2#3Cl2Ł1ðFe1OCl5Ł[1CH2CN
3[1 181
3[1 189
783999 07699
208999 14799
4[37 5[51
2[17 5[95
G[\ Studies in Surface Science and Catalysis\ 0880\
55\ 538[
single line is present\ with `ꢂ1[93 "room temperature
and 66 K#[
3[ Ondrejkovicova\ I[\ Meln(k\ M[\ Smolander\ K[
³
ꢀ
ꢀ
The EPR spectrum of the cation of complex "I#
presents one single line with `ꢂ1[95 and two
additional weak lines with `ꢂ3[23 and 5[97 at room
temperature[ It suggests a doublet ground state
³20:1 I with admixture of ³22:1 I and ³24:1 I
states[
and Ahlgren\ M[\ Acta Chem[ Scandinavica\ 0884\
ꢀ
38\ 364[
4[ Olejnik\ Z[\ Lis\ T[ and Ondrejkovicova\ I[\ Acta
³
ꢀ
Cryst[\ 0884\ C40\ 1135[
5[ Cotton\ S[ A[ and Gibson\ J[ F[\ J[ Chem[ Soc[\
A[\ 0860\ 748[
6[ Beagley\ B[\ Kelly\ D[ G[\ Mac Rory\ P[ P[\ McAu!
li}e\ C[ A[ and Pritchard\ R[ G[\ J[ Chem[ Soc[\
Dalton Trans[\ 0889\ 1546[
7[ Haselhorst\ G[\ Wieghardt\ K[\ Keller\ S[ and Sch!
rader\ B[\ Inor`[ Chem[\ 0882\ 21\ 419[
8[ Dehnicke\ K[\ Prinz\ H[\ Massa\ W[\ Pebler\ J[
and Schmidt\ R[\ Z[ Anor`[ All`[ Chem[\ 0872\
388\ 19[
09[ Petridis\ D[ and Terzis\ A[\ Inor`[ Chim[ Acta\
0875\ 007\ 018[
The magnetic data for the ð"Ph2AsO#3FeOFeCl2Ł¦
cation\ indicated only one unpaired electron per every
Fe"III# centre\ in a core of Fe"III# ðD3h deformedŁÐOÐ
Fe"III# ðTd deformedŁ#[
Further\ the magnetic data at temperatures lower
than 19 K are identical with the expected magnetism
exclusively for the cation and indicate a singlet ground
state and upper triplet state[
However\ for complex II calculation of the mag!
netic moment of the cation was found to be impossible
because we have not any possibility to estimate mag!
netism of the isolated FeCl−3 anion[ It was imposible\
too\ to compare magnetic properties of ð"Ph2AsO#3
FeOFeCl2Ł¦ cations from crystal lattice of the com!
plexes I and II[
We also prepared another unsymmetrical oxo!
bridged diiron"III# complexes with ð"Ph2AsO#3
FeOFeBr2Ł¦ cation and study of their properties is in
progress[
00[ Neuse\ E[ W[\ Khan\ F[ B[ D[\ Berhalter\ K[ and
Thewalt\ U[ J[\ Crystallo`r[ Spectr[ Res[\ 0875\ 05\
372[
01[ Drew\ M[ G[ B[\ McKee\ B[ and Nelson\ S[ M[\
J[ Chem[ Soc[\ Dalton Trans[\ 0867\ 79[
02[ Vasilevski\ I[\ Stenkamp\ R[ E[\ Lingafelter\ E[ C[
and Rose\ N[ J[\ J[ Coord[ Chem[\ 0877\ 08\ 060[
03[ Schmidbaur\ H[\ Zybill\ C[ E[ and Neugebauer\
D[\ An`ew[ Chem[\ Int[ Ed[ En`l[\ 0872\ 11\ 045[
04[ Ponomarev\ V[ I[\ Arutyunyan\ L[ D[ and
Atovmyan\ L[ O[\ Kristallo`ra_ya\ 0873\ 18\ 809[
05[ Rei}\ W[ M[\ Witten\ E[ H[\ Mottle\ K[\ Brennan\
T[ F[ and Garafalo\ A[ R[\ Inor`[ Chim[ Acta\
0872\ 66\ L72[
Atomic
coordinates\
displacement
factor
coe.cients\ full list of bond length and angles and lists
of Fo:Fc values have been deposited as supplementary
data with the Editor\ from whom copies are available
on request[ Atomic coordinates have also been
deposited with the Cambridge Crystallographic Data
Centre[
06[ Healy\ P[ C[\ Skelton\ B[ W[ and White\ A[ H[\
Aust[ J[ Chem[\ 0872\ 25\ 1946[
07[ Weiss\ H[ and Strahle\ J[\ Z[ Naturforsch\ 0873\
Ã
28b\ 0342[
08[ Carty\ P[\ Clare\ K[ C[\ Creighton\ J[ R[\ Metcalfe\
E[ and Raper\ E[ S[\ Inor`[ Chim[ Acta\ 0875\ 001\
002[
19[ Evans\ P[ J[ M[\ Fritzsimmons\ B[ W[\ Marshall\
W[ G[\ Golder\ A[ J[\ Larkworthy\ L[ F[\ Povey\
D[ C[ and Smith\ G[ W[\ J[ Chem[ Soc[\ Dalton
Trans[\ 0881\ 0954[
10[ Mabbs\ F[ E[\ McLachlan\ V[ N[\ McFadden\ D[
and McPhail\ A[ T[\ J[ Chem[ Soc[\ Dalton Trans[\
0862\ 1905[
11[ Davies\ J[ E[ and Gatehouse\ B[ M[\ Acta Cryst[\
0862\ B18\ 1540[
Acknowled`ements*The work was _nancial supported by
the State Committee for Scienti_c Research "Warsaw\
Poland# and the Ministry of Education of the Slovak Repub!
lic for _nancial support[
REFERENCES
0[ Vancova\ V[\ Ondrejkovicova\ I[ and Ondrejovic\
³
ꢀ
³
ꢀ
³
G[\ Chem[ Zvesti[\ 0873\ 25\ 252[
1[ Ondrejkovicova\ I[\ Vancova\ V[ and Ondrejovic\
³
ꢀ
³
ꢀ
³
12[ Davies\ J[ E[ and Gatehouse\ B[ M[\ Cryst[ Struct[
Comm[\ 0861\ 0\ 004[
G[\ Chem[ Papers\ 0880\ 34\ 24[
2[ Ondrejkovic³ova\ I[\ Vanc³ova\ V[ and Ondrejovic³\
ꢀ
ꢀ

2081
I[ Ondrejkovicova et al[
³ ꢀ
13[ Wang\ X[\ Pennington\ W[ T[\ Ankers\ D[ L[ and 32[ Mockler\ G[ M[\ de Jersey\ J[\ Zerner\ B[\ O|Con!
Fanning\ J[ C[\ Polyhedron\ 0881\ 00\ 1142[
14[ Davies\ J[ E[ and Gatehouse\ B[ M[\ Acta Cryst[\
0862\ B18\ 0823[
15[ Atovmyan\ L[ O[\ Dyaczenko\ A[ O[ and
Soboleva\ S[ V[\ Zh[ Strukt[ Khim[\ 0869\ 00\ 446[
16[ Mukherjee\ R[ N[\ Stack\ T[ D[ P[ and Holm\ R[
H[\ J[ Am[ Chem[ Soc[\ 0877\ 009\ 749[
17[ Yampolskaja\ M[ A[\ Shova\ S[ G[\ Gerbeleu\ N[
V[\ Simonov\ J[ A[\ Belskij\ V[ K[ and Dvorkin\
A[ A[\ Zh[ Neor`an[ Khim[\ 0872\ 17\ 0633^ J[
Coord[ Chem[\ 0872\ 17\ 873[
18[ Weiss\ M[ C[ and Goedken\ V[ L[\ Inor`[ Chem[\
0868\ 07\ 708[
nor\ C[ J[ and Sinn\ E[\ J[ Am[ Chem[ Soc[\ 0872\
094\ 0780[
33[ Kitajima\ N[\ Ito\ M[\ Fukui\ H[ and Moro!oka\
Y[\ J[ Chem[ Soc[\ Chem[ Commun[\ 0880\ 091[
34[ Coda\ A[\ Kamenar\ B[\ Prout\ K[\ Carruthers\ J[
R[ and Rollett\ J[ S[\ Acta Cryst[\ 0864\ B20\ 0327[
35[ Ercolani\ C[\ Monacelli\ F[\ Dzugan\ S[\ Goedken\
V[ L[\ Pennesi\ G[ and Rossi\ G[\ J[ Chem[ Soc[\
Dalton Trans[\ 0880\ 0298[
36[ Plowman\ J[ E[\ Loehr\ T[ M[\ Schauer\ C[ K[ and
Anderson\ O[ P[\ Inor`[ Chem[\ 0873\ 12\ 2442[
37[ Hazell\ A[\ Jensen\ K[ B[\ McKenzie\ C[ J[ and
Toftlund\ H[\ Inor`[ Chem[\ 0883\ 22\ 2016[
38[ Taft\ K[ L[\ Masschelein\ A[\ Liu\ S[\ Lippard\
S[ J[\ Gar_nkel!Shweky\ D[ and Bino\ A[\ Inor`[
Chim[ Acta\ 0881\ 087!199\ 516[
49[ Gomez!Romero\ P[\ DeFotis\ G[ C[ and Jameson\
G[ B[\ J[ Am[ Chem[ Soc[\ 0875\ 097\ 740[
40[ Gomez!Romero\ P[\ Witten\ E[ H[\ Rei}\ W[ M[\
Backes\ G[\ Sanders!Loehr\ J[ and Jameson\ G[
B[\ J[ Am[ Chem[ Soc[\ 0878\ 000\ 8928[
41[ Gomez!Romero\ P[\ Witten\ E[ H[\ Rei}\ W[ M[
and Jameson\ G[ B[\ Inor`[ Chem[\ 0889\ 18\ 4100[
42[ Collamati\ I[\ Dessy\ G[ and Fares\ V[\ Inor`[
Chim[ Acta\ 0875\ 000\ 038[
29[ Ho}man\ A[ B[\ Collins\ D[ M[\ Day\ V[ W[\
Fleischer\ E[ B[\ Srivastava\ T[ S[ and Hoard\ J[
L[\ J[ Am[ Chem[ Soc[\ 0861\ 83\ 2519[
20[ Swepston\ P[ N[ and Ibers\ J[ A[\ Acta Cryst[\
0874\ C30\ 560[
21[ Bartczak\ T[ J[\ Latos!Grazynski\ L[\ Wys<ouch\
¾
A[\ Inor`[ Chim[ Acta\ 0889\ 060\ 194[
22[ Strauss\ S[ H[\ Pawlik\ M[ J[\ Skowyra\ J[\
Kennedy\ J[ R[\ Anderson\ O[ P[\ Spartalian\ K[
and Dye\ J[ L[\ Inor`[ Chem[\ 0876\ 15\ 613[
23[ Kiong!Lam\ Lay\ Buchler\ J[ W[\ Kenny\ J[ E[
and Scheidt\ W[ R[\ Inor`[ Chim[ Acta\ 0875\ 012\
80[
43[ Lippard\ S[ J[\ An`ew[ Chem[\ Int[ Ed[ En`l[\ 0877\
16\ 233[
24[ Ivanca\ M[ A[\ Lappin\ A[ G[ and Scheidt\ W[ R[\
Inor`[ Chem[\ 0880\ 29\ 600[
25[ Gold\ A[\ Jayaraj\ K[\ Doppelt\ P[\ Fischer\ J[ and
Weiss\ R[\ Inor`[ Chim[ Acta\ 0877\ 049\ 066[
26[ Kamenar\ B[ and Kaitner\ B[\ Cryst[ Struct[
Comm[\ 0871\ 00\ 1932[
27[ Chia Chih\ Ou[\ Wollmann\ R[ G[\ Hendrickson\
D[ N[\ Potenza\ J[ A[ and Schugar\ H[ J[\ J[ Am[
Chem[ Soc[\ 0867\ 099\ 3606[
28[ Heath\ S[ L[\ Powell\ A[ K[\ Utting\ H[ L[ and
Helliwell\ M[\ J[ Chem[ Soc[\ Dalton Trans[\ 0881\
294[
44[ Ondrejkovicova\ I[\ Lis\ T[\ Mrozinski\ J[\
³
ꢀ
ꢀ
Vancova\ V[ and Meln(k\ M[\ Inor`[ Chim[ Acta\
³
ꢀ
ꢀ
in press[
45[ Figgis\ B[ N[ and Nyholm\ R[ S[\ J[ Chem[ Soc[\
0847\ 3089[
46[ Konig\ E[\ Magnetic Properties of Coordination
Ã
and
Organometallic
Transition
Metal
Compounds\ SpringerÐVerlag\ Berlin\ 0855[
47[ Sheldrick G[ M[\ SHELXL 82[ Program for Crys!
tal Structure Re_nement[ University of Got!
Ã
tingen\ Germany\ 0882[
39[ Healy\ P[ C[\ Patrick\ J[ M[ and White\ A[ H[\
Aust[ J[ Chem[\ 0873\ 26\ 0394[
48[ Meln(k\ M[\ Ondrejkovicova\ I[\ Vancova\ V[ and
ꢀ
³
ꢀ
³
ꢀ
Holoway\ C[ E[\ Rev[ Inor`[ Chem[\ 0886\ 06\ 44[
59[ Kurtz\ D[ M[ Jr[\ Chem[ Rev[\ 0889\ 89\ 474[
50[ Hart\ J[ R[\ Rappe\ A[ K[\ Gorun\ S[ M[ and
Upton\ T[ H[\ Inor`[ Chem[\ 0881\ 20\ 4143[
30[ Konefal\ E[\ Loeb\ S[ J[\ Willis\ C[ J[ and Stephan\
D[ W[\ Inor`[ Chim[ Acta\ 0875\ 004\ 036[
31[ Wieghardt\ K[\ Pohl\ K[\ Bossek\ U[\ Nuber\ B[
and Weiss\ J[\ Z[ Naturforsch\ 0877\ 32b\ 0073[