Organometallic gold derivatives with the [1-SitBuMe2-1,2-C2B1 0H1 0]-carboranyl ligand. Crystal structure of [1-{Au (PPh3)}-2-SitBuMe2-1,2-C2B 10

Article abstract of DOI:10.1016/S0277-5387(98)00224-1

Reaction of 1-Li-2-Si^tBuMe₂-1,2-C₂B₁₀H ₁₀ with [AuCIL] (L=PPh₃, PPh₂Me, AsPh₃) in molar ratio 1:1 affords the organometallic gold complexes [1-AuL-2-Si^tBuMe

Full text of DOI:10.1016/S0277-5387(98)00224-1

Polyhedron Vol[ 06\ No[ 12Ð13\ pp[ 3052Ð3056\ 0887
Þ 0887 Elsevier Science Ltd
Pergamon
All rights reserved[ Printed in Great Britain
9166Ð4276:87 ,08[99¦9[99
\
PII] S9166Ð4276"87#99113Ð0
Organometallic gold derivatives with the
ð0!SitBuMe1!0\1!C1B09H09Ł!carboranyl ligand[
Crystal structure of ð0!"Au"PPh2##!1!
SitBuMe1!0\1!C1B09H09Ł
Olga Crespo\ M[ Concepcion Gimeno\ Antonio Lagunaꢁ and Ana M[ Pena
ꢀ
½
Departamento de Qu(mica Inorganica\ Instituto de Ciencia de Materiales de Aragon\ Universidad de
ꢀ
ꢀ
ꢀ
Zaragoza!CSIC\ 49998 Zaragoza\ Spain
"Received 05 March 0887^ accepted 1 June 0887#
Abstract*Reaction of 0!Li!1!SitBuMe1!0\1!C1B09H09 with ðAuCILŁ "LꢂPPh2\ PPh1Me\ AsPh2# in molar ratio
0]0 a}ords the organometallic gold complexes ð0!AuL!1!SitBuMe1!0\1!C1B09H09Ł[ The complex PPNðAu"1!
SitBuMe1!0\1!C1B09H09#1Ł "PPNꢂN"PPh2#1# has also been synthesised by reaction of PPNðAuCl1Ł with 0!Li!1!
SitBuMe1!0\1!C1B09H09 in molar ratio 0]1[ The crystal structure of ð0!"Au"PPh2##!1!SitBuMe1!0\1!C1B09H09Ł
has been established by X!ray di}raction[ Þ 0887 Elsevier Science Ltd[ All rights reserved
Keywords] gold^ carborane
———————————————————————————————————————————————
INTRODUCTION
ð08\ 19Ł\ who prepared the complexes ðAu"1!R!
0\1!C1B09H09#"PPh2#Ł ðRꢂH\ Me\ PhŁ[ More recently
species of stoichiometry ðAu"1!R!0\1!C1B09H09#LŁ
ðRꢂCH1OCH2\ Ph^ LꢂPPh2\ P"o!tol#2\ PCy2\ PEt2\
AsPh2Ł have been reported by Reid and Welch ð10Ł
whereas in the work published by Hawthorne et al[
ð11Ł dimetallated species of o!carborane and bis"o!
carborane# have been synthesised[
We have reported recently on the synthesis of the
_rst m!carborane derivatives bonded to gold by 1cÐ1e
s!bond ð12Ł as part of our studies with carborane
derivatives ð13Ð29Ł[ Our contribution this time is
related to some new organometallic gold"I# derivatives
with the carboranyl group ð0!SitBuMe1!0\1!
C1B09H09Ł−[ This carboranyl derivative has been
described as a good precursor in the synthesis of
monosubstituted carborane derivatives ð20Ł[
The synthesis of carboranyl derivatives has been
extensively studied because in some aspects they
resemble organic compounds with electron!accepting
groups ð0Ð3Ł[ During the past decade investigations in
the _eld of C!substituted carboranes have involved
the creation of new models to be used in theoretical
investigations ð4Ł\ the preparation of organic and
organometallic carboranyl compounds for the pro!
duction of polymeric materials ð5Ð7Ł "and references
cited therein# and biological and medical inves!
tigations ð8Ł[ These compounds have proved par!
ticularly useful in the boron neutron capture therapy
"BNCT# for cancer ð09Ð02Ł[
It is known that o!carborane derivatives form
unusually strong AuÐC bonds[ Nevertheless\ examples
of closo!carboranes s!bonded to gold by 1cÐ1e s!
bonds are relatively rare "as opposed to the most
studied nido!carboranes interacting gold via cluster
bonding# ð03Ð07Ł[
RESULTS AND DISCUSSION
The _rst report was made by Mitchel and Stone
The treatment of 0!SitBuMe1!0\1!C1B09H00 with
LinBu leads to the lithiated derivative 0!Li!1!Sit!
BuMe1!0\1!C1B09H09 "0# which is not isolated^ further
reaction of 0 with the organochloro complexes
ðAuClLŁ a}ords the organometallic derivatives ð0!
ꢁ Author to whom correspondence should be addressed[
Tel[] ¦23!865!650!074^ Fax] ¦23!865!650!076^ E!mail] ala!
gunaÝposta[unizar[es[
3052

3053
Olga Crespo et al[
"AuL#!1!SitBuMe1!C1B09H09Ł ðLꢂPPh2 "1#\ PPh1Me ðAu1"m!0\6!C1B09H09#"PPh2#1Ł "1[154"1#\ 1[160"1# A#
Ä
"2# and AsPh2 "3#Ł "Scheme 0#[ and can also be compared with those found in com!
Ä
Complexes 1Ð3 behave as nonconductors in acetone plexes of the type ðAuR"PPh2#Ł "RꢂC5F4\ 1[16"0# A#
solutions[ In their IR spectra the y"BH# absorptions ð21Ł[
Ä
appear at 1481 "br\ vs#\ "1#\ 1553 "br\ vs# "2# and 1455
The AuÐC"0# distance\ 1[949"3# A\ is of the same
"br\ vs# "3# cm−0\ respectively[
order as those obtained for the complexes commented
The positive liquid secondary!ion mass spectra below "1[943"6#\ 1[936"6# A for the m!carborane
"LSIMS# of complexes 1Ð3 show the molecular peaks derivative^ 1[928"7# and 1[928"7# A for the mono and
Ä
Ä
at m:zꢂ605 "1\ 49)#\ 486 "2\ 4)# and 659 "3\ 39)#\ disubstituted o!carborane derivatives respectively#[ It
although the most intense ones correspond to the frag! has been shown that the AuÐC distances depend on
ments ðAuL1Ł¦ ðm:z 610 "1#\ 486 "2# and 798 "3#Ł[
the hybridisation state of the carbon atom[ The dis!
Compounds 1 and 2 exhibit only one signal in their tances found in the commented o!carboranyl and m!
20P"0H# NMR spectra down_eld referred to the carboranyl complexes are clearly characteristic values
starting materials "Ddꢂ3[7 "1# and 4[4 "2# ppm#[
of a carbon with sp1 hybridisation ð19Ł\ which range
Ä
In the 0H NMR spectra of 1Ð3 a multiplet and a from 1[94 to 1[98 A[ These short AuÐC distances in
broad signal appear which correspond to the phenylic carborane derivatives support Stone|s observations
protons "6Ð6[7 ppm# and the BH protons "0Ð2 ppm# that the unusual stability of auracarboranes is attri!
respectively[ All of them exhibit two resonances due buted to the electron withdrawing in~uence of the
to the SitBuMe1 fragment at about 0[9 and 9[4 ppm[ cage[ The fact that a similar stability is observed in
In addition to this pattern\ compound 2 displays one gold!per~uoroalkyl compounds\ with the AuÐC dis!
doublet due to the methyl protons of the phosphine tances only slightly longer\ but in the range of an sp1
ligand[
Complex 1 has been characterised by X!ray di}rac!
hybridisation\ is coherent with such a conclusion[
No organometallic derivative of this ligand has been
tion studies and the structure is shown in Fig[ 0[ Selec! reported as far as we know\ but no appreciably dis!
ted bond lengths and angles are collected in Table 0[ tortion is expected for the SitBuMe1 group from one
In the molecule the gold centre exhibits a distorted compound to another\ thus the SiÐC"1# distance
Ä
linear geometry\ PÐAuÐC"0#ꢂ060[2"01#>\ although 0[813"4# A compares well with those found in 0\1!"0!
t
Ä
there are no obvious reasons for this distortion\ it SiMe 1Bu!0\1!C1B09H09#1!C5H3 ð0[840"3#\ 0[845 AŁ ð22Ł
Ä
may be possible that because the bulky nature of the as well as the C"0#ÐC"1# distance 0[695"5# A in com!
SitBuMe1 group there is some steric hindrance[ This plex 1\ 0[603"5#\ 0[696"6# A in the related species[
Ä
distorted geometry is not observed in ðAu"1!CH1OÐ
CH2#!0\1!C1B09H09#"AsPh2#Ł ðAsÐAuÐCꢂ066[94"1#>Ł in molar ratio 1]0 a}ords a compound which contains
ð10Ł[
two carboranyl groups] PPNðAu"1!SitBuMe1!0\1!
Reaction of 0 with PPNðAuCl1Ł ðPPNꢂN"PPh2#1Ł
Ä
The AuÐP distance of 1[1607"02# A is of the same C1B09H09#1Ł "4# "Figure 0#[
order than those found in another o!carboranyl com!
Compound 4 behaves as 0]0 electrolyte in acetone
pounds such as ðAu"1!H!0\1!C1B09H09#"PPh2#Ł solutions[ In the IR spectrum of 4 the y"BH# absorp!
"1[160"1# A# ð11Ł or in the m!carboranyl derivative ð12Ł tion appears at 1521 cm−0[ Its LSIMS "¦# spectrum
Ä
Scheme[ 0[

Organometallic gold derivatives
3054
Fig[ 0[ The molecule of complex 1 in the crystal showing the atom!numbering scheme\ radii are arbitrary[ H atoms are
omitted for clarity[
Ä
Table 0[ Selected bond lengths "A# and angles "># for 1
AuÐC"0#
SiÐC"2#
SiÐC"4#
PÐC"00#
PÐC"10#
1[949"3#
0[748"4#
0[786"4#
0[702"4#
0[711"3#
AuÐP
1[1607"02#
0[752"4#
0[813"4#
0[703"3#
0[695"5#
SiÐC"3#
SiÐC"1#
PÐC"20#
C"0#ÐC"1#
C"0#ÐAuÐP
060[23"01#
098[1"2#
095[0"1#
003[5"1#
095[2"1#
005[6"1#
098[5"1#
006[6"2#
011[4"2#
008[0"2#
007[5"2#
007[6"2#
095[1"2#
010[8"3#
007[1"3#
010[0"2#
C"2#ÐSiÐC"3#
C"3#ÐSiÐC"4#
C"3#ÐSiÐC"1#
C"00#ÐPÐC"20#
C"20#ÐPÐC"10#
C"20#ÐPÐAu
C"1#ÐC"0#ÐAu
B"2#ÐC"0#ÐAu
B"3#ÐC"0#ÐAu
C"0#ÐC"1#ÐSi
B"2#ÐC"1#ÐSi
C"7#ÐC"4#ÐSi
C"5#ÐC"4#ÐSi
C"01#ÐC"00#ÐP
C"11#ÐC"10#ÐP
C"21#ÐC"20#ÐP
098[0"2#
C"2#ÐSiÐC"4#
C"2#ÐSiÐC"1#
C"4#ÐSiÐC"1#
C"00#ÐPÐC"10#
C"00#ÐPÐAu
C"10#ÐPÐAu
B"4#ÐC"0#ÐAu
B"5#ÐC"0#ÐAu
B"6#ÐC"1#ÐSi
B"00#ÐC"1#ÐSi
B"5#ÐC"1#ÐSi
C"6#ÐC"4#ÐSi
C"05#ÐC"00#ÐP
C"15#ÐC"10#ÐP
C"25#ÐC"20#ÐP
098[8"1#
096[8"1#
094[8"1#
093[3"1#
002[0"1#
015[0"2#
007[6"2#
004[5"2#
010[8"2#
019[1"2#
000[3"2#
002[8"2#
007[8"3#
011[3"3#
008[3"3#
presents the molecular peak as the most intense at trophotometer using Nujol mulls between poly!
m:zꢂ601[ The 0H NMR spectrum of 4 exhibits a ethylene sheets[ Conductivities were measured in ca[
similar pattern to those commented above for 1 and 4×09−3 mol dm−2 solution with a Philips PW 8498
3[
conductimeter[ C and H analyses were carried out
with a PerkinÐElmer 1399 microanalyser[ Mass spec!
tra were recorded on a VG Autospec\ with the liquid
secondary ion mass spectrometry "LSIMS ¦# tech!
EXPERIMENTAL
Infrared spectra were recorded in the range from nique using nitrobenzylalcohol as matrix[ NMR spec!
3999 to 199 cm−0 on a Perkin!Elmer 772 spec! tra were recorded on a Varian Unity 299 and Bruker

3055
Olga Crespo et al[
ARX 299 spectrometer in CDCl2[ Chemical shifts are X!ray crystal structure determination of 1
cited relative to 74) H2PO3 "external\ 20P# and SiMe3
"external\ 0H#[
Crystal Data] 1\ C15H39AuB09PSi\ Mrꢂ605[60\
triclinic\ space group PÞ0\ aꢂ09[053"1#\ bꢂ01[446"2#\
Ä
cꢂ03[199"1# A\ aꢂ004[579"09#\ bꢂ82[939"09#\ gꢂ
Startin` materials
2
Ä
091[699"09#\ Uꢂ0469[4"4# A \ Zꢂ1\ Dcꢂ0[405 Mg
m−2\ l "Mo!Ka#ꢂ9[60962 A\ mꢂ3[68 mm−0\ F"999#ꢂ
Ä
o!carborane was from Desxil Corporation and Sit!
BuMe1Cl was from Aldrich\ both of them were used
as given[ Compounds 0!SitBuMe1!0\1!C1B09H00 ð20Ł\
ðAuCl"PPh2#Ł\ ðAuCl"PPh1Me#Ł\ ðAuCl"AsPh2#Ł ð23Ł
and PPNðAuCl1Ł ð24Ł were synthesised according to
the literature procedures[
697\ Tꢂ−099>C[ Single crystals were obtained by a
slow di}usion of n!hexane into a dichloromethane
solution of complex 1[ A colourless prism 9[49×
9[39×9[29 mm was used to collect 4450 intensities
to 1umaxꢂ49> "Siemens P3 di}ractometer\ mono!
chromated Mo!Ka radiation# of which 4008 were
independent "Rintꢂ9[921#[ An absorption correction
based on C!scans was applied with transmission
factors 9[488Ð9[752[ Cell constants were re_ned from
setting angles of 53 re~ections in the range 1u from 09
to 14>[ The structure was solved by the heavy!atom
method and subjected to full!matrix least!squares
re_nement on F1 "SHELXL!82#^ all the atoms were
re_ned anisotropically\ H atoms were included using
a riding model[ Re_nement proceed to wR"F1#ꢂ9[963
for 4006 re~ections and 246 parameters\ conventional
Preparation of ð0!"AuL#!1!SitBuMe1!0\1!C1B09H09
ðLꢀPPh2 "1#\ PPh1Me "2#\ AsPh2 "3#Ł
Ł
To a solution of 0!SitBuMe1!0\1!C1B09H00 "66[3 mg\
9[2 mmol# in dried diethyl ether "29 cm2# at 9>C and
under nitrogen atmosphere LinBu was added
"9[2 mmol\ 9[37 ml and 9[51 M#[ After stirring the mix!
ture for 29 min ðAuCILŁ was added ð9[2 mmol\
LꢂPPh2\ 03[7 mg^ LꢂPPh1Me\ 01[8 mg^ LꢂAsPh2\
04[8 mgŁ[ The suspension was stirred for another
29 min and allowed to warm[ After _ltration of the
suspension over celite and concentration to ca[ 4 cm2
complexes 1 "65)#\ 2 "37)# and 3 "46)# as white
solids are obtained by addition of n!hexane "ca[
09 cm2#[ 1 Anal[ ")# Found] C\ 32[94^ H\ 4[24[ Calc[
1
−2
Ä
R"F#ꢂ9[918\ S"F #ꢂ0[911\ maximum Dr 1[3 e A
[
REFERENCES
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for
C15H39AuB09PSi]
C\
32[44^
H\
4[5[
LMꢂ17 V−0 cm1 mol−0
[
0H NMR] 9[14 "s\ 5H\ CH2#\
9[77 "s\ 8H\ Bu#\ 6Ð6[5 "m\ br\ 04H\ Ph#[ 20P"0H#
NMR] 27[3 "s#[ 2 Anal[ ")# Found] C\ 27[24^ H\ 4[5[
Calc[ for C10H27AuB09PSi] C\ 27[44^ H\ 4[74[
t
LMꢂ03 V−0 cm1 mol−0
[
0H NMR] 9[24 "s\ 5H\ CH2#\
t
9[88 "s\ 8H\ Bu#\ 0[84 "d\ J"PH#ꢂ7[3 Hz\ 2H\ CH2#\
6[1Ð6[5 "m\ br\ 09H\ Ph#[ 20P"0H# NMR] 11[7 "s#[ 3
Anal[ ")# Found] C\ 30[94^ H\ 4[2[ Calc[ for
C15H39AsAuB09Si]
C\
30[24^
H\
4[3[
LMꢂ8 V−0 cm1 mol−0
[
0H NMR] 9[21 "s\ 5H\ Me#\
t
9[84 "s\ 8H\ Bu#\ 6[9Ð6[40 "m\ br\ 04H\ Ph#[
Preparation of PPNðAu"1!SitBuMe1!0\1!C1B09H09#1Ł
"4#
To a solution of 0!SitBuMe1!0\1!C1B09H00 "66[3 mg\
9[2 mmol# in dry diethyl ether "29 cm2# at 9>C and
under nitrogen atmosphere LinBu was added
"9[2 mmol\ 9[37 ml\ 9[51 M#[ After stirring the mixture
for 29 min PPNðAuCl1Ł was added ð9[04 mmol\ 01 mgŁ[
The suspension was stirred for another 29 min and
allowed to warm[ After _ltration of the suspension
over celite and concentration to ca[ 4 cm2 complex 4
"57)# is a}orded by addition of n!hexane "ca[ 09 cm2#[
Anal[ ")# Found] C\ 49[54^ H\ 5[4^ N\ 0[04[ Calc[ for
C41H79AuB19NP1Si1] C\ 38[84^ H\ 5[34^ N\ 0[0[
LMꢂ023 V−0 cm1 mol−0[ 0H NMR] 9[28 "s\ 01H\ Me#\
00[ Shelly\ K[\ Feakes\ D[ A[\ Hawthorne\ M[ F[\
Schmidt\ P[ G[\ Krisch\ T[ A[ and Bauer\ W[ F[\
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Sommerfeld\ T[ and Stone\ F[ G[ A[\ J[ Chem[
Soc[\ Chem[ Commun[\ 0880\ 0553[
t
0[91 "s\ 07H\ Bu#\ 6[35Ð6[54 "m\ br\ 29H\ Ph#[ 20P
04[ Je}ery\ J[ C[\ Jellis\ P[ A[ and Stone\ F[ G[ A[\ J[
Chem[ Soc[\ Dalton Trans[\ 0882\ 0962[
"0H# NMR] 10[1 "s#[

Organometallic gold derivatives
3056
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