Some metal complexes containing diphenylphosphinoacetic acid as a P-bonded neutral ligand. Crystal structures of [AuCl(Ph2PCH2CO2H)] and trans- [PdCl2(Ph2PCH2CO2H) 2]0.33H2O · 0.33C2H5OH

Article abstract of DOI:10.1016/S0277-5387(98)00219-8

Diphenylphosphinoacetic acid (HA) reacts as a neutral P-donor ligand with a variety of transition metal compounds to generate the new complexes [CuCl(HA)_x] (x=1 or 3), trans-[PdCl₂(HA)₂], cis-[PtCl₂(HA)₂], [AuCl(HA)] and cis-[Mo(CO)₄(HA)₂]. The crystal structure of [AuCl(HA)] involves a linear Cl-Au-P arrangement [179.0(1)°], neighbouring molecules forming hydrogen-bonded dimers in the lattice array. The hydrogen-bonding is of the planar type commonly found in free carboxylic acids with intermolecularly bonded pairs of [AuCl(HA)] molecules being related by an inversion centre. Recrystallisation of trans-[PdCl₂(HA)₂] from ethanol yields crystals of the solvate trans-[PdCl₂(HA)₂] · 0.33H₂O · 0.33C₂H₅OH. The asymmetric unit contains 1.5[PdCl₂(HA)₂] molecules along with water and ethanol molecules exhibiting only half site occupancy. For every three [PdCl₂(HA)₂] molecules two are hydrogen-bonded to neighbours using carboxylic acid groups to form chains. The third molecule differs in that hydrogen-bonding occurs between one oxygen of a carboxylic acid group and the lattice water, the oxygen of which further hydrogen-bonds to the lattice ethanol.

Full text of DOI:10.1016/S0277-5387(98)00219-8

Polyhedron Vol[ 06\ No[ 12Ð13\ pp[ 3010Ð3029\ 0887
Þ 0887 Elsevier Science Ltd
Pergamon
All rights reserved[ Printed in Great Britain
9166Ð4276:87 ,08[99¦9[99
\
PII] S9166Ð4276"87#99108Ð7
Some metal complexes containing
diphenylphosphinoacetic acid as a P!bonded neutral
ligand[ Crystal structures of
ðAuCl"Ph1PCH1CO1H#Ł and trans!
ðPdCl1"Ph1PCH1CO1H#1Ł9[22H1O = 9[22C1H4OH
Dennis A[ Edwards\$ Mary F[ Mahon and Timothy J[ Paget
Department of Chemistry\ University of Bath\ Claverton Down\ Bath BA1 6AY\ U[K[
"Received 02 March 0887^ accepted 18 May 0887#
Abstract*Diphenylphosphinoacetic acid "HA# reacts as a neutral P!donor ligand with a variety of transition
metal compounds to generate the new complexes ðCuCl"HA#xŁ "xꢀ0 or 2#\ trans!ðPdCl1"HA#1Ł\ cis!ðPtCl1"HA#1Ł\
ðAuCl"HA#Ł and cis!ðMo"CO#3"HA#1Ł[ The crystal structure of ðAuCl"HA#Ł involves a linear ClÐAuÐP arrange!
ment ð068[9"0#>Ł\ neighbouring molecules forming hydrogen!bonded dimers in the lattice array[ The hydrogen!
bonding is of the planar type commonly found in free carboxylic acids with intermolecularly bonded pairs of
ðAuCl"HA#Ł molecules being related by an inversion centre[ Recrystallisation of trans!ðPdCl1"HA#1Ł from
ethanol yields crystals of the solvate trans!ðPdCl1"HA#1Ł = 9[22H1O = 9[22C1H4OH[ The asymmetric unit contains
0[4ðPdCl1"HA#1Ł molecules along with water and ethanol molecules exhibiting only half site occupancy[ For
every three ðPdCl1"HA#1Ł molecules two are hydrogen!bonded to neighbours using carboxylic acid groups to
form chains[ The third molecule di}ers in that hydrogen!bonding occurs between one oxygen of a carboxylic
acid group and the lattice water\ the oxygen of which further hydrogen!bonds to the lattice ethanol[ Þ 0887
Elsevier Science Ltd[ All rights reserved
Keywords] diphenylphosphinoacetic acid^ gold"I#^ palladium"II#^ carboxylic acid^ hydrogen bonding[
———————————————————————————————————————————————
INTRODUCTION
and providing di}erentiation between hard and soft
metalÐligand interactions[ Taking the simplest amino!
acid as an example\ glycine forms many complexes
involving N\O!chelating glycinate anions but rather
few containing glycine itself and these display a range
of coordination types[ For example\ glycine is
zwittterionic and O\O?!bridging in ðAg1"O1C!
CH1NH2#1Ł"NO2#1 ð3Ł\ O!unidentate in ð"h!C4H4#1Ti!
"O1CCH1NH2#1ŁCl1 ð4Ł and N!unidentate in cis!
ðPtX1"NH1CH1CO1H#1Ł "XꢀCl or Br# ð5Ł[
Metal complexes derived from phosphine!sub!
stituted acetic acids are less well known[ Considering
the ligand used in this work\ diphenylphosphinoacetic
acid Ph1CH1CO1H\ "abbreviated as HA with the anion
as A−#\ structure determinations of ðPd"A#1Ł ð6Ł\
ðPtBr"A#"HA#Ł = H1O ð7Ł\ ðRh"CO#"A#"HA#Ł ð8Ł\
ðRh"A#2Ł = PhNO1 = H1O ð09Ł\ ðRhCl"H#"A#"HA#1Ł ð09Ł
and ðEt3NŁðW"CO#3"A#Ł ð00Ł con_rm that the anion is
O\P!chelating in all cases\ although it is tridentate
both bridging and chelating through the carboxylate
A vast range of metal complexes containing coor!
dinated acetate anions have been prepared and
characterised over many years but complexes con!
taining the parent acetic acid are quite rare[ Examples
include ðM"CH2CO1H#5Ł1¦ "MꢀMg\ Ca\ Mn\ Co\ Ni\
Cu and Zn# ð0Ł and a crystal structure determination
of the nickel cation as its tetra~uoroborate con_rms
that the ligands are O!unidentate ð1\ 2Ł[ A similar
picture emerges on consideration of substituted acetic
acids and their anions as ligands where the substituent
contains a group 04 donor atom[ The additional group
04 donor atoms may compete with the carboxylic
acid donor oxygens for coordination to metal centres\
increasing the number of possible coordination modes
$Author to whom correspondence should be addressed[
Fax] ¦33!0114!715!120^ E!mail] d[a[edwardsÝbath[ac[uk
3010

3011
D[ A[ Edwards et al[
unit only in ðCa"A#1Ł ð01Ł[ Three of the above com! FAB!MS "m:z#\ 587 "04) ðMŁ¦#\ 569 "5) ðMÐCOŁ¦#\
plexes also contain HA as a ligand and in each case it 531 "39) ðMÐ1COŁ¦#\ 503 "2) ðMÐ2COŁ¦#\ 475
is bonded in a P!unidentate manner\ this coordination "10) ðMÐ3COŁ¦#\ 343 "099) ðMÐ"HA#Ł¦#\ 315 "49)
mode also having been established for trans! ðMÐ"HA#ÐCOŁ¦#[
ðPdBr1"HA#1Ł ð02Ł and ðHg1Br1"m!Br#1"HA#1Ł ð03Ł[ Thus
the parent acid HA can behave as a ligand in the
manner of a diphenylalkylphosphine[ We report here
the syntheses of a number of new examples and
trans!Dichlorobis"diphenylphosphinoacetic acid#palla!
dium"II#
include discussion of two crystal structure deter!
HA "9[21 g\ 0[29 mmol# and ðPdCl1"PhCN#1Ł "9[14 g\
minations[
9[54 mmol# were allowed to react for 13 h in stirred
dichloromethane "09 cm2#[ The resulting yellowÐgreen
EXPERIMENTAL
precipitate was collected\ washed with dichlo!
romethane and dried in vacuo[ Yield\ 9[39 g\ 81)
"found] C\ 49[0^ H\ 2[77[ C17H15Cl1O3P1Pd requires C\
49[4^ H\ 2[83)#[ NMR "CD2CN#\ 0H d 2[60 "d\ CH1\
Diphenylphosphinoacetic acid was prepared by a
variation of the method of Jarolim and Podlahova
ð04Ł "found] C\ 57[8^ H\ 4[28[ C03H02O1P requires C\
1
3H\ JPHꢀ01[4#\ 6[20\ 6[43\ 6[72 "m\ Ph\ 19H#^ 02C"
0
0H# d 018[5\ 021[0\ 022[6\ 023[5^ 20P"0H# d ¦01[3[ IR
57[8^ H\ 4[25)#[ NMR "CDCl2#\ H d 2[00 "s\ CH1\
"cm−0# 0621 s\ 0696 s n"CO1#asym\ 0249 m n"CO1#sym
\
1H#\ 6[22Ð6[37 "m\ Ph\ 09H#\ 00[49 "br s\ OH\ 0H#^
0
02C"0H# d 24[0 "d\ JCPꢀ12[1\ CH1#\ 017[3 "d\
229 m n"PdCl#[ FAB!MS "m:z#\ 518 "35) ðMÐClŁ¦#\
482 "099) ðMÐ1ClÐHŁ¦#\ 249 "19) ðMÐ1ClÐ"HA#Ł¦#[
Recrystallisation from ethanol gave yellow cube!
like crystals suitable for an X!ray structure deter!
mination[ The crystals were found to contain one etha!
nol and one water solvate molecule for every three
PdCl1"HA#1 molecules "found] C\ 49[0^ H\ 3[46[
C75H75Cl5O03P5Pd2 requires C\ 49[5^ H\ 3[19)#[
2JCPꢀ5[5\ Cmeta#\ 018[9 "s\ Cpara#\ 021[3 "d\ JCPꢀ08[8\
0
Cipso#\ 025[6 "d\ 1JCPꢀ03[2\ Cortho#\ 066[1 "d\ 1JCPꢀ7[7\
CO1H#^ 20P"0H#
d # 0699 vs
−04[0[ IR "cm−0
n"CO1#asym\ 0290\ 0180 s n"CO1#sym
The starting materials
ðPdCl1"PhCN#1Ł\ ðPtCl1"PhCN#1Ł and ðAuCl"tht#Ł
"nbdꢀnorbornadiene\ thtꢀtetrahydrothiophene#
[
ðMo"CO#3"nbd#Ł\
were prepared by standard literature methods[ Mic!
roanalyses were carried out using a Carlo!Erba micro!
analysis system[ Jeol GX 169 and EX 399
cis!Dichlorobis"diphenylphosphinoacetic acid#platinum
"II#
spectrometers were used to obtain H\ 02C and 20P
0
NMR spectra[ Infrared spectra were recorded as
Nujol or hexachlorobutadiene mulls using Nicolet
409P or Perkin!Elmer 486 spectrophotometers[ Posi!
tive and negative ion FAB mass spectra were recorded
on Vacuum Generators 6969E and Autospec instru!
ments using 2!nitrobenzyl alcohol matrices[ The m:z
values reported below are based on 24Cl\ 52Cu\ 87Mo\
095Pd and 086Au\ peak intensities being expressed rela!
tive to the strongest metal!containing fragment[ Reac!
tions and subsequent manipulations were carried out
under an atmosphere of dry nitrogen as required[
A solution of HA "9[989 g\ 9[26 mmol# in dichloro!
methane "0[9 cm2# was added to a solution of
ðPtCl1"PhCN#1Ł "9[976 g\ 9[07 mmol# in dichloro!
methane "1[9 cm2#[ A further 0[9 cm2 of dichloro!
methane was added and the mixture stirred for 09 min[
The colourless solution was allowed to stand for 07 h
before collecting the precipitated product\ washing
with dichloromethane and drying in vacuo[ Yield\
9[092 g\ 65) "found] C\ 34[1^ H\ 2[38[
C17H15Cl1O3P1Pt requires C\ 33[5^ H\ 2[36)#[ NMR
0
1
"CD2CN#\ H d 2[52 "d\ CH1\ 3H\ JPHꢀ00[6#\ 6[17Ð
6[56 "m\ Ph\ 19H#^ 02C"0H# d 22[1 "s\ CH1#\ 018[3\
021[3\ 023[6^ 20P"0H# d ¦2[9 ð0J"084PtÐ20P#ꢀ2689Ł[ IR
Tetracarbonylbis"diphenylphosphinoacetic acid#molyb!
denum"9#
"cm−0#\ 0623 sh\ 0585 s n"CO1#asym\ 0299 m n"CO1#sym
221 m\ 292 m n"PtCl#[
\
A solution of ðMo"CO#3"nbd#Ł "0[99 g\ 2[2 mmol#
and HA "0[59 g\ 5[6 mmol# in dichloromethane
"19 cm2# was stirred at room temperature for 07 h[ Chloro"diphenylphosphinoacetic acid#copper"I#
The resulting colourless precipitate was removed by
_ltration\ washed with dichloromethane and dried in
Copper"I# chloride "9[19 g\ 1[9 mmol# was added to
vacuo[ Yield 1[1 g\ 85) "found] C\ 44[0^ H\ 2[61[ a stirred solution of HA "9[49 g\ 1[9 mmol# in dichlo!
C21H15MoO7P1 requires C\ 44[1^ H\ 2[65)#[ NMR romethane "09 cm2# and any reaction allowed to pro!
0
ð"CD2#1COŁ\ H d 2[14 "virtual t\ CH1\ 3H#\ 6[28 and ceed for 13 h at room temperature[ The resulting
6[40 "m\ Ph\ 19H#^ 02C"0H# d 26[7 "s\ CH1#\ 018[9 "d\ colourless precipitate was _ltered\ washed with dichlo!
1JCPꢀ06[5\ Cortho#\ 029[3 "s\ Cpara#\ 022[0 "d\ 2JCPꢀ01[0\ romethane and dried in vacuo[ Yield\ 9[32 g\ 52)
0
Cmeta#\ 026[2 "d\ JCPꢀ22[0\ Cipso#\ 058[3 "s\ CO1H#\ "found] C\ 38[0^ H\ 2[79[ C03H02ClCuO1P requires C\
1
1
109[1 "d\ JCPꢀ8[8\ CO#\ 105[0 "d\ JCPꢀ06[5\ CO#^ 38[9^ H\ 2[71)#[ NMR "CD2CN#\ 0H d 2[55 "d\ CH1\
20P"0H# d ¦14[9[ IR "cm−0# 1916 vs\ 0810 vs\ 0809 sh\ 1H\ JPHꢀ02[4#\ 6[35\ 6[57\ 6[67Ð6[72 "m\ Ph\ 09H#^
0786 vs n"CO#\ 0690 s n"CO1#asym\ 0185 m n"CO1#sym
1
1
[
02C"0H# d 23[6 "d\ CH1\ JCPꢀ01[1#\ 018[5 "d\

Some metal complexes containing diphenylphosphinoacetic acid as a P!bonded neutral ligand 3012
1
2JCPꢀ7[7\ Cmeta#\ 020[1 "s\ Cpara#\ 020[5 "d\ JCPꢀ8[8\ CO1H#Ł in Table 0[ Selected bond lengths and angles
0
Cortho#\ 022[4 "d\ JCPꢀ04[3\ Cipso#\ 069[0 "s\ CO1H#^ are reported for each compound in Tables 1 and 2\
20P"0H# d −02[2[ IR "cm−0#\ 0694 vs n"CO1#asym\ 0183 respectively[ Additional information for each struc!
s n"CO1#sym[ FAB!MS "m:z#\ FAB¦ 0222 "0) ðM3Ð ture is available from the Cambridge Crystallographic
ClŁ¦#\ 538 "59) ðM1ÐClŁ¦#\ 440 "099) ðMÐ Data Centre and comprises _nal fractional atomic
Cl¦"HA#Ł¦#\ 394 "23) ðM1ÐClÐ"HA#Ł¦#\ 231 "09) coordinates\ thermal parameters\ hydrogen atom
ðMŁ¦#^ FAB− 0257 "1) ðM3Ł−#\ 0013 "6) ðM3Ð coordinates and complete listings of bond lengths and
"HA#Ł−#\ 767 "16) ðM3Ð1"HA#Ð1HŁ−#\ 524 "34) angles[ The contents of the unit cell of the palladium
ðM3Ð2"HA#ÐHŁ−#\ 426 "099) ðM2Ð1"HA#ÐHŁ−#\ 230 compound\ produced using ORTEX ð05Ł\ is shown in
"81) ðMÐHŁ−#[
Fig[ 0 along with the labelling scheme[ Views of the
supramolecular structure highlighting the hydrogen!
bonding motifs are shown in Figs 1 and 2[ The asym!
metric unit of the gold compound is given in Fig[ 3\
also produced using ORTEX ð05Ł[
Chlorotris"diphenylphosphinoacetic acid#copper"I#
Data were collected at room temperature on a
Copper"I# chloride "9[964 g\ 9[65 mmol# slowly dis!
solved when added to a stirred solution of HA
"9[452 g\ 1[20 mmol# in dichloromethane "09 cm2#[ The
reaction was allowed to proceed for 13 h at room
temperature before removal of some of the solvent in
vacuo to yield a colourless crystalline product[ Yield\
9[22 g\ 41) "found] C\ 48[8] H\ 3[64[ C31H28ClCuO5P2
requires C\ 59[6^ H\ 3[62)#[ NMR "CDCl2#\ 0H d 2[05
"s\ CH1\ 5H#\ 6[02\ 6[21 "m\ Ph\ 29H#\ 09[96 "br\ CO1H\
CAD!3
di}ractometer
using
graphite!mon!
ochromated Mo!Ka radiation[ The di}raction inten!
sities were corrected for Lorentz and polarisation
e}ects[ An absorption correction was applied for the
gold compound "transmission factor extrema 0[999\
9[129#[ The structures were solved using SHELX75
ð06Ł and re_ned using SHELX82 ð07Ł[ In the _nal
least squares cycles all atoms were allowed to vibrate
anisotropically[ For the palladium compound\ hydro!
gen atoms were included at calculated positions on
carbon atoms\ where relevant[ Hydrogens associated
with the carboxylic acid moieties\ the hydroxyls of the
ethanol molecules and the lattice waters could not
be located\ even by examining a di}erence Fourier
synthesis based on low Bragg data[ For the gold com!
pound\ hydrogen atoms were included at calculated
positions where relevant\ except on the carboxylic acid
moieties[
2
2H#^ 02C"0H# d 22[4 "s\ CH1#\ 017[2 "d\ JCPꢀ5[5\
Cmeta#\ 018[7 "s\ Cpara#\ 020[4 "d\ 0JCPꢀ12[1\ Cipso#\ 021[3
"d\ 1JCPꢀ03[3\ Cortho#\ 060[8 "s\ CO1H#^ 20P"0H# d −8[4[
IR "cm−0#\ 0614 sh\ 0699 vs n"CO1#asym\ 0189 m
n"CO1#sym\ 136 w n"CuCl#[ FAB!MS "m:z# 684 "1)
ðMÐClŁ¦#\ 440 "099) ðMÐClÐ"HA#Ł¦#\ 152 "49)
ðMÐClÐ1"HA#ÐCO1Ł¦#[
Chloro"diphenylphosphinoacetic acid#`old"I#
A solution of HA "9[04 g\ 9[59 mmol# in dichloro!
methane "1[9 cm2# was added to a solution of chloro
"tetrahydrothiophene#gold"I# "9[19 g\ 9[59 mmol# in
dichloromethane "2[9 cm2#[ The mixture was stirred
overnight at room temperature giving a yellow solu!
tion[ Removal of the solvent in vacuo gave a yellow
crystalline solid which was recrystallised from dichlo!
romethane before drying in vacuo[ Yield\ 9[14 g\ 76)
"found] C\ 24[1^ H\ 1[69[ C03H02AuClO1P requires C\
RESULTS AND DISCUSSION
Six new complexes all involving diphenyl!
phosphinoacetic acid\ abbreviated as HA\ as a neutral
P!donor ligand have been prepared and characterised[
In these compounds the ligand is primarily acting as
an alkyldiarylphosphine\ although additional inter!
molecular hydrogen!bonding employing the car!
boxylic acid function is likely to be present in all
cases as established by X!ray crystallography for the
palladium and gold examples "vide infra#[ The com!
plexes have been prepared either by direct reaction of
the acid with a metal chloride as for ðCuCl"HA#xŁ
"xꢀ0 or 2#\ or by displacement of a suitable labile
ligand from a metal complex[ Thus the syntheses of
ðMCl1"HA#1Ł\ "MꢀPd or Pt#\ ðMo"CO#3"HA#1Ł and
ðAuCl"HA#Ł have been achieved from ðMCl1"PhCN#1Ł\
ðMo"CO#3"nbd#Ł and ðAuCl"tht#Ł\ respectively
0
24[2^ H\ 1[64)#[ NMR "CDCl2#\ H d 2[72 "d\ CH1\
1
1H\ JPHꢀ01[4#\ 6[51\ 6[71 "m\ Ph\ 09H#^ 02C"0H# d
0
0
24[9 "d\ JCPꢀ26[3\ CH1#\ 018[8 "d\ JCPꢀ50[6\ Cipso#\
2
029[2 "d\ JCPꢀ01[0\ Cmeta#\ 022[2 "s\ Cpara#\ 023[1 "d\
1JCPꢀ03[2\ Cortho#\ 057[6 "s\ CO1H#^ 20P"0H# d ¦14[9[
IR "cm−0#\ 0699 vs n"CO1#asym\ 0299 s n"CO1#sym\ 224
vs n"AuCl#[ FAB!MS "m:z# 806 "11) ðM1ÐClŁ¦#\ 574
"2) ðMÐCl¦"HA#Ł¦#\ 365 "6) ðMŁ¦#\ 330 "099)
ðMÐClŁ¦#[
"nbdꢀnorbornadiene^
thtꢀtetrahydrothiophene#[
Characterisation of products has been carried out
using 0H\ 02C and 20P NMR\ IR and FAB!MS "selected
data are given in Section 1# and for the palladium and
X!ray crystallo`raphy
Crystal data\ data collection and re_nement details gold complexes\ single crystal X!ray structure deter!
are given for trans!ðPdCl1"Ph1CH1CO1H#1Ł = minations[
9[22C1H4OH = 9[22H1O and for ðAuCl"Ph1PCH1
The 0H NMR spectra of the six complexes are very

3013
D[ A[ Edwards et al[
Table 0[ Crystal data and data collection details for trans!ðPdCl1"Ph1PCH1CO1H#1Ł = 9[22EtOH = 9[22H1O and for
ðAuCl"Ph1PCH1CO1H#Ł
Empirical formula
Formula weight
Crystal system
Space group
C32H32Cl2O6P2Pd0[4
0929[52
triclinic
C03H02AuClO1P
365[52
monoclinic
P10:n
8[185"0#
8[368"0#
¹
P0 "No[ 1#
Ä
a "A#
8[770"1#
04[573"5#
04[605"3#
Ä
b "A#
Ä
c "A#
06[423"1#
a ">#
b ">#
g ">#
76[16"2#
68[50"1#
74[67"1#
1276[5"00#
86[94"0#
2
Ä
V "A #
0422[3"2#
Z
1
3
Dc "Mg m−2
#
0[323
9[774
0933
1[954
8[755
785
m "mm−0
F"999#
#
Crystal dimensions "mm#
Theta range for data collection ">#
hkl ranges
9[2×9[2×9[14
1[09 to 12[82
9 to 00\ −06 to 06\ −06 to 06
6841
9[1×9[1×9[14
1[23 to 12[81
−09 to 09\ 9 to 09\ 9 to 19
1285
Re~ections collected
Independent re~ections "Rint
Data\ restraints\ parameters
Goodness of _t on F1
#
6350 "9[9035#
6339\ 9\ 431
0[006
1285 "9[9999#
1285\ 9\ 062
0[988
Final R0\ wR1 indices ðI×1s"I#Ł
9[9242\ 9[0903
9[9534\ 9[0216
9[735\ −9[319
0:ðs1"F1o#¦"9[9594P#1¦2[1940PŁ where
Pꢀ"F1o¦1F1c#:2
9[9227\ 9[9790
9[9530\ 9[9837
0[229\ −0[933
0:ðs1"F1o#¦"9[9400P#1¦4[9983PŁ where
Pꢀ"F1o¦1F1c#:2
"All data#
Largest residuals "e A
−2
Ä
#
Weighting scheme\ w
similar to that of diphenylphosphinoacetic acid itself[ for the mono! and tris!ligand complexes\ respectively[
The methylene resonance appears as a doublet "1J ca[ These coordination shifts are very much of the same
01 Hz# for the palladium\ platinum and gold com! magnitude as those of related metal!alkyl!
plexes as a result of coupling to phosphorus while that diphenylphosphine or !triphenylphosphine complexes
of the molybdenum tetracarbonyl appears as a virtual e[g[ cis!ðMo"CO#3"PPh1Bun#1Ł\ Ddꢀ31[8 ppm ð08Ł^
triplet\ with a quite broad central peak\ resulting from ðAuCl"Ph1PCH1CONHMe#Ł\ Ddꢀ30[8 ppm ð19Ł^
the two phosphorus nuclei being strongly coupled to ðCuCl"PPh2#2Ł = MeCN\ Ddꢀ1[2 ppm ð10Ł[ The coor!
each other[ Detection of the carboxylic acid proton dination shifts for trans!ðPdCl1"HA#1Ł and cis!
was only achieved for the ligand itself and for ðPtCl1"HA#1Ł are intermediate in magnitude being 16[4
ðCuCl"HA#2Ł[
and 07[0 ppm\ respectively[ These Dd values can be
Apart from the palladium and platinum species the compared with those of the analogous trans!ðPdCl1"P!
remainder show the expected six 02C resonances "a Ph1Bun#1Ł ð11Ł and cis!ðPtCl1"PPh1Bun#1Ł ð08Ł which are
methylene\ a carboxylic acid and four phenyl signals# 22[3 and 13[0 ppm\ respectively[ The large J"084PtÐ
0
at quite similar chemical shifts to those of the free 20P# coupling constant of 2689 Hz observed for the
ligand[ Only partial data were obtained for the pal! platinum complex is indicative of cis!square planar
ladium and platinum compounds\ as a result of low geometry\ a useful comparison ð08Ł being the values
solubilities in non!reacting solvents[ Additional car! for cis! and trans!ðPtCl1"PPh1Bun#1Ł of 2530 and
bonyl carbon resonances at 109[1 and 105[0 ppm\ with 1420 Hz\ respectively[ It appears\ therefore\ from these
appropriate 20PÐ02C coupling constants\ con_rms the Dd and J values that our preparative route leads to
anticipated cis!octahedral geometry of the molyb! the trans!isomer for the palladium compound\ as has
denum product[ The 20P chemical shift values are been established by crystallography for ðPdBr1"HA#1Ł
invariably down_eld relative to the free ligand as a ð02Ł\ whereas the platinum compound is isolated as the
result of bonding by the ligand through phosphorus[ cis!isomer[ Further evidence supporting this proposal
However\ the coordination shifts\ Dd\ vary sig! comes from infrared spectroscopic and\ for the pal!
ni_cantly from compound to compound\ the molyb! ladium complex\ crystallographic results "vide infra#[
denum and gold complexes both showing shifts of
The infrared!active asymmetric and symmetric car!
39[0 ppm whereas those of the two copper"I# com! boxylate stretches are little changed from those of the
plexes are much smaller\ being only 0[7 and 4[5 ppm free acid indicating the lack of coordination to the

Some metal complexes containing diphenylphosphinoacetic acid as a P!bonded neutral ligand 3014
Ä
Table 1[ Selected bond lengths "A# and angles "># for trans!
well with that of ðCuCl"PPh2#2Ł = MeCN ð10Ł at
138 cm−0[ A similar band for the mono!ligand com!
plex has not been detected but would be below the
lower limit of our spectrometer "199 cm−0# if it
possesses\ as we believe on the basis of mass spec!
ðPdCl1"Ph1PCH1CO1H#1Ł = 9[22EtOH = 9[22H1O
Pd"0#ÐCl"0# 1[294"0#
Pd"0#ÐP"0# 1[215"0#
Cl"0#ÐPd"0#ÐP"0#
Cl"0#ÐPd"0#ÐP"0?#
C"6#ÐP"0#ÐC"0#
C"6#ÐP"0#ÐC"02#
C"0#ÐP"0#ÐC"02#
O"0#ÐC"03#ÐO"1#
82[13"3#
75[65"3#
090[7"1#
093[4"1#
092[7"1#
011[3"3#
P"0#ÐC"6#
P"0#ÐC"0#
0[705"4#
0[710"3#
trometry evidence\
a cubane!type ðCuCl"HA#Ł3
arrangement[ The gold complex has n"AuCl# at
224 cm−0\ a similar frequency ð14Ł to that of linear
ðAuCl"PPh2#Ł\ 214 cm−0[ The palladium complex has
P"0#ÐC"02# 0[728"4#
O"0#ÐC"03# 0[144"5#
O"1#ÐC"03# 0[151"5#
Pd"1#ÐCl"1# 1[292"0#
Pd"1#ÐP"1# 1[298"0#
P"1#ÐC"04# 0[796"4#
P"1#ÐC"10# 0[703"4#
P"1#ÐC"16# 0[729"4#
O"2#ÐC"17# 0[104"5#
O"3#ÐC"17# 0[203"5#
Pd"2#ÐCl"2# 1[184"0#
Pd"2#ÐP"2# 1[226"1#
P"2#ÐC"24# 0[797"5#
P"2#ÐC"18# 0[796"4#
P"2#ÐC"30# 0[736"5#
O"4#ÐC"31# 0[153"8#
O"5#ÐC"31# 0[101"8#
Cl"1#ÐPd"1#ÐP"1#
Cl"1#ÐPd"1#ÐP"1?#
C"04#ÐP"1#ÐC"10#
C"04#ÐP"1#ÐC"16#
C"10#ÐP"1#ÐC"16#
O"2#ÐC"17#ÐO"3#
75[34"4# one band which can be assigned to n"PdCl# at
229 cm−0 whereas the platinum complex has two
82[44"4#
bands assignable to n"PtCl# at 221 and 292 cm−0[ This
is in line with the respective suggestions above of trans!
and cis!square planar geometries and also in agree!
ment with the known structure of trans!ðPdBr1"HA#1Ł
093[5"1#
092[7"1#
094[2"1#
011[3"4#
ð02Ł and the stereochemistry of the recrystallised
Cl"2#ÐPd"2#ÐP"2?#
Cl"2#ÐPd"2#ÐP"2#
C"24#ÐP"2#ÐC"18#
C"24#ÐP"2#ÐC"30#
C"18#ÐP"2#ÐC"30#
O"5#ÐC"31#ÐO"4#
89[89"4#
material
trans!ðPdCl1"HA#1Ł = 9[22EtOH = 9[22H1O
78[09"4#
095[8"2#
096[9"2#
produced in this study[
Positive and negative ion FAB mass spectra have
090[7"2# been obtained for all except the platinum compound[
013[3"6#
Generally only the major metal!containing positive
ions are given in Section 1[ One particularly novel
fragmentation involves the decarboxylation of coor!
dinated diphenylphosphinoacetic acid generating
methyldiphenylphosphine as the successor ligand[ As
expected\ stepwise loss of four carbonyl ligands is
observed for the molybdenum complex[ Both positive
and negative ion fragments are listed for ðCuCl"HA#Ł
only\ because signi_cant fragment ions of correct iso!
O"4#ÐO"7#
O"6#ÐO"7#
O"5#ÐO"7#
1[56"1#
1[80"1#
2[28"1#
O"0#ÐO"1?#
O"2#ÐO"3?#
1[503"5#
1[575"4#
All PÐPdÐP and ClÐPdÐCl angles are exactly 079[9> as
dictated by symmetry[
Symmetry transformations used to generate equivalent
atoms] P"0?# −x\ −y¦0\ −z^ P"1?# −x¦0\ −y\ −z^ P"2?#
−x¦0\ −y¦0\ −z¦0^ O"1?# 0−x\ 0−y\ z^ O"3?# −x\ −y\ topic distribution to be derived from Cu3Cl3 units
−z[
are detected[ This strongly suggests that a tetrameric
cubane!type structure akin to that of ðCuCl"PPh2#Ł3 or
a step!type stucture as shown by ðCuBr"PPh2#Ł3 =
1CHCl2 is taken up ð15\ 16Ł[ The mass spectrum of the
gold complex contains few fragments but a dimer
parent ion and the dimer less one chloride ligand are
both detected in agreement with the solid state struc!
ture discussed below[
Ä
Table 2[ Selected bond lengths "A# and angles"># for
ðAuCl"Ph1PCH1CO1H#Ł
Au"0#ÐP"0#
P"0#ÐC"0#
P"0#ÐC"6#
P"0#ÐC"02#
O"0#ÐO"1?#
P"0#ÐAu"0#ÐCl"0# 068[9"0#
C"0#ÐP"0#ÐAu"0# 003[3"2#
C"6#ÐP"0#ÐAu"0# 002[3"2#
1[119"1#
0[797"7#
0[792"7#
0[713"8#
1[507"8#
Au"0#ÐCl"0#
C"03#ÐO"0#
C"03#ÐO"1#
C"02#ÐC"03#
1[169"2#
0[126"09#
0[154"00#
0[403"01#
Recrystallisation of trans!ðPdCl1"HA#1Ł from etha!
nol
gave
crystals
of
trans!ðPdCl1"HA#1Ł =
9[22EtOH = 9[22H1O showing rather di}erent IR band
frequencies to those of the unsolvated complex ðe[g[
nasym"CO1# 0694\ 0583 and nsym"CO1# 0291 cm−0Ł[ The
crystal stucture is quite involved\ the asymmetric unit
containing three half molecules of the complex tog!
ether with one molecule each of water and ethanol\
both at half site occupancy\ i[e[ 0 H1O and 0 EtOH for
every 2 palladiums[ Three independent square planar
trans!ðPdCl1"HA#1Ł species are present in the structure\
all three metal atoms being located at inversion centres
intrinsic to the space group symmetry[ Fig[ 0 shows a
portion of the overall structure with the asymmetric
C"0#ÐP"0#ÐC"6#
C"6#ÐP"0#ÐC"02#
C"02#ÐP"0#ÐC"0#
095[5"3#
090[4"3#
095[3"3#
C"02#ÐP"0#Ð
Au"0#
002[4"2#
O"0#ÐC"03#ÐO"1# 011[4"7#
Symmetry transformations used to generate O"1?#] 0−x\
0−y\ 1−z[
metals via this part of the ligand but not excluding the unit delineated by those labelled atoms which are
likelihood of carboxylic acid hydrogen!bonding which unprimed[ Two of the trans!ðPdCl1"HA#1Ł units\ those
is also present in the free acid ð12Ł[ The molybdenum involving Pd"0# and Pd"1#\ are similar and are involved
tetracarbonyl complex exhibits four strong n"CO# in the formation of a one!dimensional polymeric array
stretches as predicted for a cis!octahedral species\ the along the a axis via two!fold hydrogen bonding to
frequencies being very similar to those of cis!ðMo"C! lattice neighbours through carboxylic acid groups "see
O#3"PPh2#1Ł ð13Ł[ The copper"I# tris!ligand complex Fig[ 1#[ This form of hydrogen bonding is directly
shows a n"CuCl# stretch at 136 cm−0 which compares related to that found in carboxylic acids themselves\

3015
D[ A[ Edwards et al[
Fig[ 0[ The unit cell contents of ðPdCl1"Ph1PCH1CO1H#1Ł = 9[22EtOH = 9[22H1O showing the labelling scheme[ The asymmetric
unit comprises the atoms with unprimed labels[ Thermal ellipsoids are at the 29) probability level[
e[g[ acetic acid ð17Ł[ These polymers are stacked in the metal centre is co!planar with its attached donor
b direction and alternate between Pd"0#! and Pd"1#! atoms\ the metal centres have\ nonetheless\ slightly
containing molecules at half unit cell intervals[ The di}erent coordination environments[ For example\
trans!ðPdCl1"HA#1Ł moieties containing Pd"2# are the three individual PdÐCl bond lengths are quite con!
Ä
di}erent\ "see Fig[ 2#[ These molecules are not sistent ð1[184"0#\ 1[292"0# and 1[294"0# AŁ whereas the
involved in carboxylic acid derived hydrogen bonding PdÐP bond lengths vary signi_cantly ð1[215"0#\
Ä
to generate polymeric arrays[ Rather\ discrete hydro! 1[298"0# and 1[226"1# AŁ[ However\ the mean of the
gen!bonded entities are formed by interaction of the ! PdÐP bond lengths exactly matches that determined
Ä
OH of each carboxylic acid unit with the oxygen of for trans!ðPdBr1"HA#1Ł\ 1[221 A ð02Ł[ Also\ whereas
each water molecule present[ The water molecules are the species containing Pd"2# has ClÐPdÐP angles close
then further hydrogen!bonded to the ethanol solvent to the ideal 89> ð78[09"4#>Ł\ the corresponding angles
molecules[ Given that the protons associated with ! associated with Pd"0# and Pd"1# show some deviation
CO1H\ H1O and ethanol hydroxyl groups could not ð75[65"3# and 75[34"4#>\ respectivelyŁ[ Although a
Ä
be located in the crystallographic study\ the presence Pd [ [ [ O separation of 2[060"5# A was regarded as evi!
of the various types of hydrogen bonding was inferred dence of a weak additional interaction in the structure
from short O [ [ [ O distances[
of trans!ðPdBr1"HA#1Ł ð02Ł\ the shortest Pd [ [ [ O con!
Ä
Despite the fact that all three metal atoms are situ! tact in the present structure is 2[15 A between Pd"0#
ated at inversion centres\ thus rendering all PÐPdÐP and O"1# and we do not feel that this is signi_cant[
and ClÐPdÐCl angles with a value of 079> where each For all three molecules\ the PÐCH1CO1H bond lengths

Some metal complexes containing diphenylphosphinoacetic acid as a P!bonded neutral ligand 3016
Fig[ 1[ View down the c axis of the palladium compound showing the one!dimensional chains formed by hydrogen bonded
carboxylic acid groups[
are noticeably longer than the PÐC"aryl# bond lengths\ O [ [ [ O distances of molecules involving Pd"1# centres\
Ä
a feature much less apparent in trans!ðPdBr1"HA#1Ł[ 1[575"4# A\ are similar to those found in trans!
Conversely\ within the !CH1CO1H groups\ the mean ðPdBr1"HA#1Ł ð02Ł\ cis!ðPtBr"A#"HA#Ł ð7Ł\ cis!
Ä
CÐC bond length of 0[381 A is rather shorter than that ðRh"CO#"A#"HA#Ł ð8Ł and\ indeed\ in the free acid ð12Ł\
Ä
Ä
of trans!ðPdBr1"HA#1Ł at 0[412 A[ The three molecules being 1[609"6#\ 1[519"5#\ 1[56 and 1[559"6# A\ respec!
show quite di}erent carboxylic acid CÐO bond leng! tively[ The hydrogen bonding involved in linking mol!
ths\ the distinction between the formal CÐOH and ecules containing Pd"0# is of the same type with a
Ä
C O bonds being most obvious in the molecules con! slightly shorter O [ [ [ O interaction of 1[503"5# A[ The
taining Pd"1# ðdi}erence 9[988"5# AŁ\ which is very hydrogen bonding associated with molecules con!
1
Ä
similar to that of trans!ðPdBr1"HA#1Ł ðdi}erence taining Pd"2# does not generate a polymer as a conse!
Ä
9[984"8# AŁ ð02Ł[ This di}erence is less signi_cant in quence of only 49) site occupancy of the water and
Ä
the molecules containing Pd"2# ðdi}erence 9[941"8# AŁ ethanol solvate molecules[ The O [ [ [ O contacts
and essentially absent in molecules containing Pd"0# between O"4# of the complex containing Pd"2# and
Ä
ðdi}erence 9[996"5# AŁ[ This unexpected observation O"7# of H1O and between O"7# of H1O and O"6# of
Ä
may relate to the type\ degree of asymmetry and extent EtOH are 1[56"1# and 1[80"1# A\ respectively\ the latter
of the hydrogen bonding for each molecular species[ therefore indicating a much weaker form of hydrogen
Di}erences between the three molecules are also bonding than that of the carboxylic acid variety in the
marked when the various PdÐPÐC\ PÐCÐC and CÐPÐ molecular structure[ The _nal carboxyl oxygen\ O"5#
C angles are considered\ although details will not be is unique among the six carboxylic acid oxygens in
given here[ The OÐCÐO angles in each of the three not being involved in intermolecular hydrogen bond!
molecules are slightly greater than 019> ð011[3"3#\ ing\ as is evident from the long O"5# [ [ [ O"7# sep!
Ä
011[3"4# and 013[3"6#>Ł\ the largest angle being associ! aration of 2[28"1# A[
ated with molecules containing Pd"2#[
In the complex ðAuCl"HA#Ł\ the gold displays linear
The intermolecular hydrogen bonding involving coordination ðClÐAuÐP 068[9"0#>Ł with two individual
molecules containing Pd"0# and Pd"1# generates two molecules linked into a dimer "Fig[ 3# again with two
Ä
sets of one!dimensional polymeric chains "Fig[ 1#[ The sets of O [ [ [ O interactions of 1[507"8# A\ which are

3017
D[ A[ Edwards et al[
Fig[ 2[ View down the c axis of the palladium compound showing the discrete hydrogen bonding involving carboxylic acid\
water and ethanol molecules[ Only 49) occupancy of the positions of the solvent molecules is observed[

Some metal complexes containing diphenylphosphinoacetic acid as a P!bonded neutral ligand 3018
Fig[ 3[ ORTEX plot of the hydrogen bonded dimer of ðAuCl"Ph1PCH1CO1H#Ł showing the labelling scheme[ Thermal
ellipsoids are at the 29) probability level[
REFERENCES
slightly shorter than those for the palladium com!
pound noted above[ The individual CÐO bond lengths
of 0[126"09# and 0[154"00# A suggest that the car!
Ä
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boxylic acid protons are not quite symmetrically
placed in the hydrogen bonding array\ being more
closely associated with O"1# rather than O"0#[ The
hydrogen bonded dimers are formed by assembling
neighbouring molecules in the lattice which are spa!
tially related by an inversion centre[ Typically\ O"0#
and O"1# of the molecule as presented are hydrogen
bonded to O"1?# and O"0?#\ respectively\ of the neigh!
bouring molecule generated via the operator 0−x\
0−y\ 1−z[ The OCO angle of 011[4"7#> compares to
that of 011[1"3#> for the free acid ð12Ł which displays
a similar hydrogen bonding arrangement[ The hydro!
gen bonding system holds the AuCl units well apart
prohibiting intra!dimer aurophilic Au [ [ [ Au contacts
which have been identi_ed in the structures of some
linear gold"I# compounds ð18Ł[
Ä
The AuÐCl bond length of 1[169"2# A is very similar
to those of ðAuCl"PPh2#Ł ð29Ł and ðAuCl"Ph1PCH1
Ä
C"O#NHMe#Ł ð19Ł ð1[168"2# and 1[164"1# A\ respec!
Ä
tivelyŁ and the AuÐP bond length of 1[119"1# A also
compares well with those of the above two complexes
Ä
ð1[124"2# and 1[110"0# A\ respectivelyŁ[ The PÐ
CH1CO1H bond length is\ as found for the palladium
complex\ slightly longer than the PÐC"aryl# bond leng!
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Ä
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CÐPÐAu and CÐPÐC bond angles "002[7 and 093[7>\
respectively# are closely similar to those of
Ä
ðAuCl"PPh2#Ł ð29Ł "0[719 A\ 002[4> and 094[0>\ respec!
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a !CH1CO1H group has little e}ect structurally\ apart
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Acknowled`ements*We thank EPSRC for a maintenance
grant "to T[ J[ P[#[
08[ Pregosin\ P[ S[ and Kunz\ R[ W[\ 20P and 02C NMR

3029
D[ A[ Edwards et al[
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