2,6-Bis(diphenylphosphinosulfide)pyridine (L) as a facial terdentate ligand: Synthesis and characterisation of the tricarbonylrhenium(I) complexes fac-[Re(CO)3L]+ [Re2(CO)6(μ-X)3]- (X=Cl, Br or I) and fac-[Re(CO)3L]+ [SbF6]-

Article abstract of DOI:10.1016/S0277-5387(98)00196-X

The halogenopentacarbonylrhenium(I) compounds react with 2,6-bis(diphenylphosphinosulfide) pyridine (L) under mild conditions to yield ionic complexes of general formulae, fac-[Re(CO)₃L]⁺ [Re₂(CO)₆ (μ-X)₃]^- (X=Cl, Br or I), in which the ligand adopts a facial terdentate bonding mode. A synthesis of [Re(CO)₃L]⁺ [SbF₆]^- was carried out to establish the presence of the cation, fac-[Re(CO)₃L]⁺, in the complexes. The character of the anions was confirmed by negative ion MALDI-TOF mass spectrometry. The cation is fluxional; the P-phenyl rings oriented towards the metal moiety exhibit restricted rotation at low temperature. The free energy of activation, ΔG ^?, for hindered rotation is ca. 47 kJ mol^-1 for all complexes. Solid-state ³¹P NMR data are reported for the free ligand and for the complexes, [Re(CO)₃L][SbF₆] and [Re(CO)₃L][Re₂(CO)₆(μ-X)₃] (X=Cl, Br or I).

Full text of DOI:10.1016/S0277-5387(98)00196-X

Polyhedron Vol[ 06\ No[ 12Ð13\ pp[ 2870Ð2876\ 0887
Þ 0887 Elsevier Science Ltd
Pergamon
All rights reserved[ Printed in Great Britain
9166Ð4276:87 ,08[99¦9[99
\
PII] S9166!4276"87#9908!X
1\5!Bis"diphenylphosphinosul_de#pyridine "L# as
a facial terdentate ligand] synthesis and
characterisation of the tricarbonylrhenium"I#
complexes fac!ðRe"CO#2LŁ¦
ðRe1"CO#5"m!X#2Ł− "XꢀCl\ Br or I# and
fac!ðRe"CO#2LŁ¦ ðSbF5Ł−
Peter J[ Heardaꢀ and Abil E[ Alievb
aDepartment of Chemistry\ Birkbeck College\ Gordon House\ 18 Gordon Square\
London WC0H 9PP\ U[K[
bDepartment of Chemistry\ University College London\ Christopher Ingold Laboratories\
19 Gordon Street\ London WC0H 9AJ\ U[K[
"Received 2 April 0887^ accepted 01 May 0887#
Abstract*The halogenopentacarbonylrhenium"I# compounds react with 1\5!bis"diphenylphosphinosul_de#
pyridine "L# under mild conditions to yield ionic complexes of general formulae\ fac!ðRe"CO#2LŁ¦ ðRe1"CO#5
"m!X#2Ł− "XꢁCl\ Br or I#\ in which the ligand adopts a facial terdentate bonding mode[ A synthesis of
ðRe"CO#2LŁ¦ ðSbF5Ł− was carried out to establish the presence of the cation\ fac!ðRe"CO#2LŁ¦\ in the
complexes[ The character of the anions was con_rmed by negative ion MALDI!TOF mass spectrometry[ The
cation is ~uxional^ the PÐphenyl rings oriented towards the metal moiety exhibit restricted rotation at low
temperature[ The free energy of activation\ DG$\ for hindered rotation is ca[ 36 kJ mol−0 for all complexes[
Solid!state 20P NMR data are reported for the free ligand and for the complexes\ ðRe"CO#2LŁðSbF5Ł and
ðRe"CO#2LŁðRe1"CO#5"m!X#2Ł "XꢁCl\ Br or I#[ Þ 0887 Elsevier Science Ltd[ All rights reserved
Keywords] tricarbonylrhenium"I#^ solid!state NMR^ phosphine ligands[
———————————————————————————————————————————————
INTRODUCTION
eochemical behaviour exhibited by transition metal
complexes of this type\ we chose to investigate the
tricarbonylrhenium"I# halide complexes of 1\5!bis
"diphenylphosphinosul_de#pyridine "L#[ It was
expected that\ under mild conditions\ the ligand would
react with the halogenopentacarbonylrhenium"I#
compounds\ to form complexes of general formulae
fac!ðReX"CO#2LŁ "XꢁCl\ Br or I#\ with the ligand
bound in a bidentate fashion via the N donor of the
pyridine ring and one of the sulfur donors[ However\
analytical and spectroscopic data indicate that ionic
complexes of the type fac!ðRe"CO#2LŁ¦ A− "where A is
the counter ion# are formed\ with the ligand adopting a
facial terdentate bonding mode[ Accordingly\ we
report here on the synthesis and characterisation of
the complexes fac!ðRe"CO#2LŁ¦ ðRe1"CO#5"m!X#2Ł−
"XꢁCl\ Br or I# and fac!ðRe"CO#2LŁ¦ ðSbF5Ł−[
Metal complexes of ligands that have unco!
ordinated donor atoms are now well established as
~uxional species[ The classical example of this type of
~uxional behaviour is exhibited by transition metal
complexes of 1\1?]5?\1ý!terpyridine "terpy#\ in which
terpyridine is restricted to a bidentate bonding mode
ð0\ 1Ł[ Other potentially terdentate ligands\ such as
1\5!bis"oxazolinyl#pyridines ð2\ 3Ł and 1\5!bis"sul!
fanyl#pyridines ð4\ 5Ł\ also display ~uxional behaviour
when coordinated to a metal in a bidentate fashion[
As part of our on!going interest in the dynamic ster!
ꢀ Author to whom correspondence should be addressed[
E!mail] p[heardÝchem[bbk[ac[uk[
2870

2871
P[ J[ Heard and A[ E[ Aliev
London School of Pharmacy[ Fast atom bombard!
EXPERIMENTAL
ment "FAB# mass spectra were carried out on a VG
Analytical ZAB!SE instrument\ using Xe¦ ion bom!
bardment at 7 kV energy[ Matrix assisted laser desorp!
Syntheses
All manipulations were carried out under an atmo! tion:ionisation time of ~ight "MALDI!TOF# mass
sphere of dry oxygen!free nitrogen\ using standard spectra were obtained on a Fisons TofSpec instru!
Schlenk techniques ð6Ł[ Solvents were dried ð7Ł and ment\ with a linear ~ight path of 9[8 m\ operating in
degassed before use[ The pentacarbonylrhenium"I# the negative ion mode[ The laser was _red _fty times
halides ð8Ł were prepared using previously published at minimal energy\ to produced the averaged spectra[
procedures and the ligand\ 1\5!bis"diphenyl! The matrix used was 4!chloro!1!mercapto!
phosphinosul_de#pyridine "L# was prepared by Pro! benzothioazole[ X!Ray powder patterns were
fessor W[ McFarlane ð09Ł[ The three complexes obtained by Dr I[ P[ Parkin\ University College
ðRe"CO#2LŁ¦ðRe1"CO#5"m!X#2Ł− "XꢁCl\ Br or I# were London\ on a Siemens D4999 X!ray powder di}ract!
prepared similarly\ as illustrated by the procedure for ometer\ using Ge monochromated Cu!Ka radiation
ðRe"CO#2LŁ¦ðRe1"CO#5"m!Br#2Ł−[ The hexa~uoro! "lꢁ0[4395 Aý#[
0
antimonate complex was prepared by treatment of
Solution!state H\ 08F and 20P NMR spectra were
ðRe"CO#4"thf#Ł¦ ðSbF5Ł− with 1\5!bis"diphenylphos! recorded in CD1Cl1 or CDCl2 on a Bruker AMX399
phinosul_de#pyridine\ and from ðRe"CO#2LŁ¦ Fourier transform spectrometer\ operating at 399[02\
ðRe1"CO#5"m!Br#2Ł−\ by treatment with AgSbF5\ as 265[34 and 050[87 MHz\ respectively[ Chemical shifts
described[
are reported relative to tetramethylsilane "0H#\ CFCl2
"
08F# and 74) aqueous H2PO3 "20P#[ NMR probe
temperatures were controlled by a standard B!VT
1999 unit^ probe temperatures were periodically
checked "099) MeOH# and are considered accurate
to within20>C[
ðRe"CO#2LŁðRe1"CO#5"m!Br#2Ł
Pentacarbonylrhenium"I#
bromide
"019 mg\
9[184 mmol# and 1\5!bis"diphenylphosphinosul_de#
pyridine "049 mg\ 9[182 mmol# were heated under
re~ux in 19 cm2 of a 49]49 "v:v# mixture of benzeneÐ
petroleum ether "b[p[ 59Ð79>C# for ca[ 07 h[ The result!
ing orange solid was isolated by _ltration\ and recrys!
tallised from dichloromethane[ Yield] 66 mg\ 49)[
High!resolution solid!state 20P NMR spectra were
recorded at 010[4 and 131[8 MHz on Bruker MSL299
and AMX599 Fourier transform spectrometers\
respectively\ equipped with standard Bruker magic
angle spinning probes[ Spectra were measured at
ambient temperature "187 K#\ on polycrystalline pow!
ders in zirconia rotors with a 3 mm external diameter[
Chemical shifts are quoted relative to 74) aqueous
H2PO3[ Spectra were recorded using a {{single!pulse||
sequence with magic angle spinning and high!power
0H decoupling[ The isotropic peaks were identi_ed by
varying the MAS frequencies "2Ð00 kHz# and the prin!
cipal components of the 20P CSA tensor "d00\ d11 and
d22# were determined using the HerzfeldÐBerger
method ð00Ł ðprior to the spinning side!band analyses\
the overlapping resonances were deconvoluted using
the NUTS "Acorn NMR# line _tting subroutineŁ[ The
chemical shielding anisotropy\ Ds\ and the asymmetry
parameter\ h\ are de_ned as ð01Ł] Dsꢁð"d00¦d11#:1Ł−
d22 and hꢁ"d00−d11#:"diso−d22#\ where disoꢁ"d00¦
d11¦d22#:2[
ðRe"CO#2LŁðSbF5Ł
Method A ðReBr"CO#4Ł "49 mg\ 9[012 mmol# and
AgSbF5 "29 mg\ 9[016 mmol# were re~uxed in 04 cm2
of tetrahydrofuran "thf# for ca[ 1 h[ The resulting solu!
tion was _ltered "to remove AgBr# and then added to
a
stirred solution of 1\5!bis"diphenylphosphino!
sul_de#pyridine "69 mg\ 9[026 mmol in 4 cm2 of thf#[
The reaction mixture was re~uxed for ca[ 07 h\ then
the solvent removed in vacuo\ to yield a yellowÐorange
solid[ Recrystallisation from dichloromethaneÐpen!
tane yielded 59 mg "37)# of yellow ðRe"CO#2LŁðSbF5Ł[
Method B ðRe"CO#2LŁðRe1"CO#5"m!Br#2Ł "099 mg\
9[95 mmol# and AgSbF5 "14 mg\ 9[095 mmol# were
stirred at ambient temperature for ca[ 13 h\ in 19 cm2
of CH1Cl1[ The resulting yellow solution was _ltered
"to remove AgBr# and evaporated to dryness in vacuo[
The crude yellow product was crystallised from
dichloromethaneÐpentane[ Yield] 53 mg\ 87)[
RESULTS AND DISCUSSION
Treatment
of
the
halogenopentacarbonyl!
rhenium"I# compounds with a stoichiometric quantity
of 1\5!bis"diphenylphoshinosul_de#pyridine "L# "Fig[
0# under moderate conditions was expected to yield
complexes of general formulae fac!ðReX"CO#2LŁ
Physical methods
Infrared spectra were recorded in CH1Cl1\ using "XꢁCl\ Br or I#\ with the ligand bound to the metal
matched CaF1 solution cells on a Nicolet 194 FT!IR in a bidentate fashion ðstructure "II#\ Fig[ 0Ł[ However\
spectrometer operating in the region 3999Ð399 cm−0
[
microanalytical data indicated the formation of com!
Elemental analyses were carried out at University plexes of molecular formulae Re2"CO#8X2L[ The fast
College London[ Mass spectra were obtained at the atom bombardment "FAB# mass spectra of all three

1\5!Bis"diphenylphosphinosul_de#pyridine "L# as a facial terdentate ligand
2872
Fig[ 0[ The structures of the free ligand "L#\ the ðRe"CO#2LŁ cation "I# and the expected complexes\ ðReX"CO#2LŁ "II#[ The
hydrogen atom labelling schemes for the ligand and "I# are shown alongside[
complexes displayed a molecular ion at m:z¦ꢁ671\ ment of the ðRe"CO#4"thf#Ł¦ cation with a stoi!
which corresponds to the species ðRe"CO#2LŁ¦ ðstruc! chiometric quantity of 1\5!bis"diphenylphoshino!
ture "I#\ Fig[ 0Ł "the observed and calculated isotope sul_de#pyridine "L#\ yielded ðRe"CO#2LŁðSbF5Ł as a
patterns are consistent#[ Since rhenium!halide bonds yellow solid "see above#[ Treatment of ðRe"CO#2LŁ
in halogenotricarbonylrhenium"I# complexes usually ðRe1"CO#5"m!Br#2Ł with AgSbF5 also yielded
remain intact on ionisation ð02Ł\ FAB mass spectral ðRe"CO#2LŁðSbF5Ł[ Data "FAB!MS\ IR and NMR# for
data indicate the formation of a cationic species\ in the cation in ðRe"CO#2LŁðSbF5Ł were the same as for
which the ligand acts in a terdentate bonding mode[ the proposed cation in the complexes\ ðRe"CO#2LŁ
As the cation stoichiometry is Re"CO#2L\ the counter ðRe1"CO#5"m!X#2Ł "XꢁCl\ Br or I#[ Attempts were
ions must have the molecular formulae "from the C\ made to grow single crystals for X!ray crystallo!
H and N analyses# Re1"CO#5X2 "XꢁCl\ Br or I#[ Com! graphic studies in order to con_rm unambiguously
plex anions of this stoichiometry are know^ namely the the terdentate bonding mode of the ligand^ suitable
triply halide!bridged dirhenium anions\ ðRe1"CO#5"m! crystals could not be obtained[
X#2Ł− "XꢁCl\ Br or I# ð03\ 04Ł[ Negative ion mass
All four complexes\ ðRe"CO#2LŁðRe1"CO#5"m!X#2Ł
spectrometry "using the MALDI!TOF technique# was "XꢁCl\ Br or I# and ðRe"CO#2LŁðSbF5Ł\ are stable
carried out on the complexes to con_rm the nature of in the solid!state under ambient conditions\ and are
the anions^ molecular ions were observed for the three soluble in moderately polar solvents "e[g[ CH1Cl1#[ In
complexes at m:z−ꢁ534 "XꢁCl#\ 668 "XꢁBr# and coordinating solvents\ such as acetone and methanol\
819 "XꢁI#\ due to the proposed anions[ Analytical the complexes quickly decompose^ infrared spec!
data are reported in Table 0[
troscopy indicates the formation of the ðRe"CO!
Attempts to prepare the desired complexes\ #2"solvent#2Ł¦ cation and a quantitative yield of the
ðReX"CO#2LŁ\ by treatment of the rheniumpenta! free ligand is recovered[
carbonyl halides with 1\5!bis"diphenylphoshino!
sul_de#pyridine under milder conditions "CH1Cl1^ played three bands in the carbonyl stretching region\
ambient temperature# were unsuccessful^ the ionic characteristic of fac!octahedral coordination
The infrared spectrum of ðRe"CO#2LŁðSbF5Ł dis!
a
species\ ðRe"CO#2LŁðRe1"CO#5"m!X#2Ł "XꢁCl\ Br or I#\ geometry\ with local Cs symmetry\ for the Re"CO#2
were again isolated "although reaction times were sig! moiety ð05Ł[ The free ligand displays a strong band
ni_cantly longer#[
at 536 cm−0 due to the P1S stretching mode ð09Ł[
To con_rm the presence of the ðRe"CO#2LŁ¦ cation Although no band assignable unambiguously to the
in the complexes isolated "see above#\ an explicit syn! P1S stretch in the cation\ ðRe"CO#2LŁ¦\ was
thesis of the hexa~uoroantimonate salt\ ðRe"CO#2LŁ¦ observed\ the band at 536 cm−0 is absent in the IR
ðSbF5Ł− was carried out[ Reaction of ðReBr"CO#4Ł with spectrum of the complex^ infrared data therefore
AgSbF5 in tetrahydrofuran "thf#\ followed by treat! clearly indicate that the ligand\ 1\5!bis"di!

2873
P[ J[ Heard and A[ E[ Aliev
Table 0[ Analytical data for the complexes ðRe"CO#2LŁðRe1"CO#5"m!X#2Ł "XꢁCl\ Br or I# and ðRe"CO#2LŁðSbF5Ł
n"CO#a "cm−0
#
Analysesd
H
Complex
Colour
orange
cation
anione
m:z¦ b m:z− c
C
N
ðRe"CO#2LŁðRe1"CO#5"m!Cl#2Ł
1925
1913 "1929#
671
671
671
671
534 20[83 "20[83# 0[27 "0[51# 9[80 "9[87#
668 18[16 "18[11# 0[27 "0[37# 9[73 "9[89#
819 15[85 "15[79# 0[08 "0[25# 9[66 "9[71#
123 25[77 "26[66# 1[94 "1[17# 0[25 "0[27#
0838 ½0819 "0806#
0819
ðRe"CO#2LŁðRe1"CO#5"m!Br#2Ł
ðRe"CO#2LŁðRe1"CO#5"m!I#2Ł
ðRe"CO#2LŁðSbF5Ł
orange
orange
yellow
1925
1912 "1917#
0838 0809sh "0804#
0819
1925
1907 "1901#
0838 0894sh "0803#
0819
1925
0838
0819
aInfrared data^ spectra recorded in CH1Cl1 solution[
bFAB mass spectral data "cation#[
cNegative ions mass spectral data[
dCalculated values in parentheses[
eLiterature value given in parentheses "see Ref[ ð03Ł#^ shꢁshoulder[
phenylphoshinosul_de#pyridine\ is acting in a fac! bonding mode or "ii# the ligand is undergoing some
terdentate bonding mode with the S atoms coor! rapid ~uxional process that leads to the averaging of
dinated to the metal[ The IR spectra of the complexes
ðRe"CO#2LŁðRe1"CO#5"m!X#2Ł "XꢁCl\ Br or I# each dis!
played three bands due to the CO stretching modes of
the cation "these were in identical positions to those
observed for the SbF5 salt#\ plus additional bands due
to the counter ions\ ðRe1"CO#5"m!X#2Ł− "XꢁCl\ Br or
I#[ No band assignable to the free P1S stretching
mode "see above# was observed[ The isolated
ðRe1"CO#5"m!X#2Ł− anions have local D2h symmetry
and are therefore expected to exhibit two IR active
carbonyl stretching modes "A1ý and E?#[ The sharp
A1ý bands are clearly observed to slightly lower fre!
quency of the A0 band of the cation[ The E? bands
di}erent P environments[ To try to distinguish
between these two possibilities spectra were recorded
at low temperature "089 K#\ in an attempt to {{freeze!
out|| any dynamic stereochemical processes[ No spec!
tral changes were observed\ indicating
a ster!
eochemically rigid molecule\ with the two P atoms in
identical chemical positions[ Solution 20P NMR data
therefore indicate the formation of complex\ in which
both S"ꢁPPh1# atoms of the ligand are bound to the
metal centre[ This was con_rmed by solid!state 20P
NMR spectroscopy "see below#[
The solid!state 20P spectrum of the free ligand\ 1\5!
bis"diphenylphoshinosul_de#pyridine\ displays two
isotropic resonances\ with spinning side!bands\ in a
0]0 intensity ratio at dꢁ30 and 27\ as a result of the
two P atoms being crystallographically inequivalent[
The spectra also indicate the presence of residual
dipolar coupling between the nitrogen "03N nuclide#
of the pyridine ring and the phosphorus nuclides[ We
are currently undertaking a full analysis of the solid!
state NMR spectra of 1\5!bis"diphenylphoshino!
sul_de#pyridine and the related oxide and selenide
compounds\ and will report the results of these studies
shortly[
tend to overlap with the cation band at 0819 cm−0
^
however\ the E? bands of the bromo! and iodo!species
are observable[ The CO stretching frequencies for the
anions are close to those reported previously for the
complexes ðEt3NŁðRe1"CO#5"m!X#2Ł "XꢁCl\ Br or I#\
in the same solvent "CH1Cl1# ð03Ł[ Infrared data are
reported in Table 0[
NMR studies
The ambient temperature "187 K# 20P"0H# NMR
spectra of the complexes ðRe"CO#2LŁðRe1"CO#5"m!X#2Ł
"XꢁCl\ Br or I# and ðRe"CO#2LŁðSbF5Ł in CD1Cl1 are\
as expected\ identical[ The spectra display a single
resonance at d¼56[9 ðcf[ dꢁ27[3 for the free ligand
"in CDCl2#Ł\ indicating that either "i# both P are equi!
The solid!state 20P NMR spectra of the complexes
ðRe"CO#2LŁðRe1"CO#5"m!X#2Ł "XꢁCl\ Br or I# also dis!
play two isotropic resonances "with spinning side!
bands#\ in a 0]0 "integral# intensity ratio at ca[ dꢁ54
and 51[ The small chemical shift di}erences between
valent\ as a result of the ligand adopting a symmetrical the signals indicate that they arise as a result of the P

1\5!Bis"diphenylphosphinosul_de#pyridine "L# as a facial terdentate ligand
2874
atoms being crystallographically inequivalent\ rather "¼6[7 Hz#^ thus HJ gives rise to a pseudo septet[ The
than as a result of chemical inequivalence[ This clearly signal from HK:HK? is then readily identi_ed from a
supports the hypothesis of the ligand bonding in a 0HÐ0H COSY experiment "see below#[
symmetrical fashion\ with both S atoms coordinated[
If rotation about the PÐC"phenyl# bonds is assumed
The hexa~uoroantimonate salt\ ðRe"CO#2LŁðSbF5Ł\ to be rapid at ambient temperature "187 K#\ as appears
displays two isotropic signals\ in a 0]0 intensity ratio\ apparent from the 0H NMR spectra\ the hydrogen
at ca[ dꢁ60 and 55[ The di}erent chemical shifts of nuclides of the PÐphenyl rings would be expected to
the isotropic resonances of the ðSbF5Ł− complex com! give rise to three resonances\ characteristic of an
pared to those of the other three complexes "see above# AA?BB?C spin system[ Thus the six remaining chemi!
presumably arise because of di}erent packing in the cal shifts "see above# must result from inequivalence
solid!state[ This interpretation is supported by the of pairs of phenyl rings[ This inequivalence arises
results of X!ray powder di}raction studies on the four because two phenyl rings point towards the metal
complexes[ The powder patterns obtained for the moiety and two away from it Fig[ 0[ If the inequiv!
complexes ðRe"CO#2LŁðRe1"CO#5"m!X#2Ł "Xꢁ Cl\ Br alence arose as a result of an unsymmetrical mode of
or Br# are essentially identical\ but are di}erent from co!ordination\ then all four PÐphenyl rings would be
that obtained for ðRe"CO#2LŁðSbF5Ł[ The solid!state expected to be inequivalent "see Fig[ 0# and twelve
20P NMR spectrum of ðRe"CO#2LŁðRe1"CO#5"m!Br#2Ł distinct chemical shifts would result[ Ambient tem!
0
is shown in Fig[ 1 and 20P NMR data for the ligand\ perature H NMR data are therefore consistent with
1\5!bis"diphenylphosphinosul_de#pyridine and the either "i# a symmetrical bonding mode for the ligand
four complexes\ ðRe"CO#2LŁðRe1"CO#5"m!X#2Ł "XꢁCl\ or "ii# the presence of rapid ~uxional process that leads
Br or I# and ðRe"CO#2LŁðSbF5Ł are reported in Table 1[
to a time!averaging of pairs of phenyl rings[ The latter
The ambient temperature "187 K# 0H NMR spectra possibility can be excluded to the basis of the 20P
of the complexes ðRe"CO#2LŁðRe1"CO#5"m!X#2Ł NMR data "see above# and the results of a low tem!
0
"XꢁCl\ Br or I# and ðRe"CO#2LŁðSbF5Ł ðLꢁ1\5!bis"di! perature H NMR study "see below#[ The resonances
phenylphosphinosul_de#pyridineŁ in CD1Cl1 are of the ortho!hydrogens of the phenyl rings are readily
essentially identical[ The spectra displayed eight dis! identi_ed by their couplings to the phosphorus
tinct chemical shifts in the region dꢁ6[1Ð7[1 and are nuclides "2JPH¼03Ð04 Hz#[ The remaining signals
indicative of the ligand bonding in a symmetrical "Table 2# can then be assigned on the basis of a single
fashion[ The signals of the pyridine!H nuclides\ HJ\ 0HÐ0H COSY experiment[ The assignment of the two
H
K and HK? Fig[ 0\ show the characteristic pattern of sets of phenylÐH signals to the two pairs of phenyl
an ABB? sub!set of an ABB?XX? spin system "the P rings was based on the low temperature 0H NMR
atoms being the XX? sub!set#[ The signal from HJ is spectra "see below#[ The 0H NMR spectrum of
readily assigned because the JPH coupling "¼2[7 Hz# ðRe"CO#2LŁðRe1"CO#5"m!Cl#2Ł at 187 K is shown in Fig[
is approximately half that of the JHH coupling 2 and data are reported in Table 2[
3
2
Fig[ 1[ The 010 MHz solid!state 20P NMR spectrum of ðRe"CO#2LŁðRe1"CO#5"m!Br#2Ł at two di}erent MAS frequencies[ The
MAS frequencies are shown alongside and the isotropic peaks are denoted ꢀ[

2875
P[ J[ Heard and A[ E[ Aliev
Table 1[ Phosphorus!20 NMR dataa for L and the complexes ðRe"CO#2LŁðRe1"CO#5"m!X#2Ł "XꢁCl\ Br or I# and
ðRe"CO#2LŁðSbF5Ł
Compound
db
27[3 "26[6#c
56[9
diso
d00
d11
d22
Ds
h
Ligand
30
27
54
51
54
51
54
51
60
55
091
87
87
87
75
091
75
095
73
093
73
68
−66
−71
−24
−38
−24
−40
−18
−49
−07
−16
066
079
049
056
049
058
031
057
022
028
9[92
9[99
9[46
9[18
9[48
9[11
9[50
9[15
9[58
9[60
ðRe"CO#2LŁðRe1"CO#5"m!Cl#2Ł
ðRe"CO#2LŁðRe1"CO#5"m!Br#2Ł
ðRe"CO#2LŁðRe1"CO#5"m!I#2Ł
ðRe"CO#2LŁðSbF5Ł
032
023
033
020
030
022
034
034
56[0
55[7
55[7
aAmbient temperature "187 K# solid!state NMR data except for b^ CSA tensors assigned according to the Haeberlen
convention "Ref[ ð01Ł#[
bAmbient temperature "187 K# solution NMR data^ spectra recorded in CDCl2 or CD1Cl1 "see text#[
cLiterature value give in parentheses ðsee Ref[ ð09Ł "solvent not reported#Ł[
A variable temperature 0H NMR study of the com! indicative of restricted rotation about the PÐC"phenyl#
plexes was undertaken\ between ambient temperature bonds of one pair of phenyl rings were observed on
"187 K# and ca[ 199 K\ to help con_rm the ster! cooling[ If it is assumed that the phenyl rings oriented
eochemical rigidity of the complexes\ and thence the towards the metal moiety have the higher magnitude
symmetrical bonding mode of the ligand\ 1\5!bis"di! for the free energy of activation "DG$# for the PÐC
phenylphosphinosul_de#pyridine[ Although the 0H "phenyl# bond rotation\ as a consequence of steric
NMR spectra are temperature dependent "see below#\ interactions with the metal moiety\ a full assignment
there was no evidence to indicate the slowing of an of the phenylÐH resonances to the two pairs of rings
oscillatory rearrangement\ that would be expected if can be made[ Assignments were made on this basis
the ligand were bound in a bidentate fashion ð0Ð5Ł[ "Table 2#[ A full analysis of the variable temperature
0
The low temperature H NMR spectra are therefore spectra was not undertaken[ Approximate values for
consistent with a stereochemically rigid symmetrical the free energies of activation were determined ð06Ł at
bonding mode for the ligand[ Band shape changes the temperature of initial line broadening "Ti¼192 K#
Fig[ 2[ The ambient temperature 399 MHz 0H NMR spectrum of ðRe"CO#2LŁðRe1"CO#5"m!Cl#2Ł[ See Fig[ 0 for labelling[

1\5!Bis"diphenylphosphinosul_de#pyridine "L# as a facial terdentate ligand
Table 2[ Hydrogen!0 NMR dataa for L and the cation\ ðRe"CO#2LŁ¦
2876
Compoundb
Ligand
d"HA:HA?# d"HB:HB?#
d"HC#
d"HD:HD?# d"HE:HE?#
d"HF#
d"HK:HK?#
d"HJ#
7[96
6[59 6[29
6[49
7[60
"6[4c\ 9[7c\ "6[4c\ 1[7d# "6[4c\ 9[7c\
"6[7c\ 03[0d# "6[7c\ 2[7d#
02[2 d#
0[1d#
e
e
ðRe"CO#2LŁ¦ A−
7[96
6[68
6[80
6[49
6[65
"6[3c\ 9[7c\
0[7d#
7[05
"6[5c\ 9[7c\ "6[5c\ 2[5d# "6[5c\ 9[7c\ "6[3c\ 9[7c\
"6[6c\ 2[6d#
04[0d#
0[8d#
03[0d#
aData recorded at 187 K^ 0H chemical shifts quoted relative to tetramethylsilane^ spectra of the complexes were recorded
in CH1Cl1^ spectrum of the ligand recorded in CDCl2^ see Fig[ 0 for labelling[
bA−ꢁðRe1"CO#5"m!X#2Ł− "XꢁCl\ Br or I# or ðSbF5Ł−[
cn
J
J
"Hz#[
"Hz#[
HH
dn
PH
eHE:HE? and HK:HK? overlap\ giving a complex multiplet centred at ca[ 6[5 ppm[
and from band coalescence "Tc¼132 K#^ DG$¼
36 kJ mol−0 at both Ti and Tc[ The apparent tem!
perature independence of DG$ indicates that the
entropy of activation\ DS$\ is approximately zero\ as
expected for an intramolecular process[ The activation
energies measured were the same for all four
complexes\ consistent with the presence of the same
cation in each case[
³
A[ G[\ Pain\ H[ M[ and Sik\ V[\ J[ Chem[ Soc[
Chem[ Commun[\ 0881\ 292[
1[ Abel\ E[ W[\ Orrell\ K[ G[\ Osborne\ A[ G[\ Pain\
³
H[ M[\ Sik\ V[\ Hursthouse\ M[ B[ and Malik\ K[
M[ A[\ J[ Chem[ Soc[ Dalton Trans[\ 0883\ 2330
and references therein[
2[ Heard\ P[ J[ and Jones\ C[\ J[ Chem[ Soc[ Dalton
Trans[\ 0886\ 0972[
3[ Heard\ P[ J[ and Tocher\ D[ A[\ J[ Chem[ Soc[
Dalton Trans[ "in press#[
0
Although the H and 20P NMR data clearly show
that the ligand is co!ordinated to the metal centre in
a symmetrical fashion\ via both S atoms\ data do not
exclude the possibility that the ligand is bound in a
bidentate fashion\ with the N donor of the pyridine
ring uninvolved in bonding[ This is considered highly
unlikely on chemical grounds\ and is inconsistent with
the mass spectral and IR data "see above#[ The orange:
yellow colour of the complexes "which is indicative of
tricarbonylrhenium"I#Ðpyridine complexes ð2\ 02Ł# is
also consistent with the pyridine ring being bound[
The 08F NMR spectrum of the hexa~uoro!
antimonate complex\ ðRe"CO#2LŁðSbF5Ł\ was obtained
to con_rm the presence of the ðSbF5Ł− anion[ The
ambient temperature 08F spectrum "in CD1Cl1# com!
prises two overlapping sub!spectra "at dꢁ−012[3#\
4[ Abel\ E[ W[\ Ellis\ D[ and Orrell\ K[ G[\ J[ Chem[
Soc[ Dalton Trans[\ 0881\ 1132[
5[ Abel\ E[ W[\ Heard\ P[ J[\ Orrell\ K[ G[\ Hurst!
house\ M[ B[ and Mazid\ M[ A[\ J[ Chem[ Soc[
Dalton Trans[\ 0882\ 2684[
6[ Shriver\ D[ F[\ Manipulation of Air!Sensitive Com!
pounds[ McGraw!Hill\ New York\ 0858[
7[ Perrin\ D[ D[ and Armarego\ W[ L[ F[\ Puri!
_cation of Laboratory Chemicals[ Pergamon\
Oxford\ 0877[
8[ Schmidt\ S[ P[\ Trogler\ W[ C[ and Basolo\ F[\
Inor`[ Synth[\ 0868\ 17\ 059[
09[ McFarlane\ H[ C[ E[\ McFarlane\ W[ and Muir\
A[ S[\ Polyhedron\ 0889\ 8\ 0646[
00[ Herzfeld\ J[ and Berger\ A[ E[\ J[ Chem[ Phys[\
0879\ 62\ 5910[
due to coupling to 010Sb "Iꢁ4:1\ 46[14)# and 012Sb 01[ Haeberlen\ U[\ Adv[ Ma`n[ Reson[ "Suppl[ 0#[
"Iꢁ6:1\ 31[64)#^ 0Jð010SbÐFŁꢁ0834 Hz\ 0Jð012SbÐFŁꢁ
Academic Press\ 0865[
02[ Heard\ P[ J[\ Ph[ D[ Thesis\ University of Exeter\
0883 and references therein[
03[ Brisdon\ B[ J[\ Edwards\ D[ A[ and White\ J[ W[\
J[ Or`anomet[ Chem[\ 0867\ 050\ 122[
04[ Hrung\ C[ P[\ Tsutsui\ M[\ Cullen\ D[ L[\ Meyer\
E[ F[ and Morimoto\ C[ N[\ J[ Am[ Chem[ Soc[\
0867\ 099\ 5957[
05[ Edwards\ D[ A[ and Marshalsea\ J[\ J[ Or`anomet[
Chem[\ 0866\ 020\ 62[
06[ Faller\ J[ W[\ Encyclopaedia of Inor`anic Chem!
istry\ ed[ R[ B[ King[ Wiley\ New York\ 0883\ p[
2803 et seq[
07[ Harris\ R[ K[\ NMR and the Periodic Table\ eds[
R[ K[ Harris and B[ E[ Mann[ Academic Press\
0867\ p[ 270 and references therein[
0949 Hz[ Data are consistent with those reported pre!
viously for the ðSbF5Ł− anion ð07Ł[
Acknowled`ements*We are grateful to Birkbeck College for
_nancial support\ to Professor W[ McFarlane for the syn!
thesis of the ligand and to the University of London for
access to the solid!state NMR facilities at University College
London and Queen Mary and West_eld College and the
399 MHz solution NMR service at Kings College[ Dr B[ C[
Smith and Dr G[ Hogarth are acknowledged for helpful
discussions[
REFERENCES
0[ Abel\ E[ W[\ Long\ N[ J[\ Orrell\ K[ G[\ Osborne\