Synthesis and X-ray crystal structure of [CuI(R2PS)2]3

Full text of DOI:10.1021/ic990276b

4152
Inorg. Chem. 1999, 38, 4152-4155
Synthesis and X-ray Crystal Structure of
[CuIN(R2PS)2]3
David J. Birdsall, Alexandra M. Z. Slawin, and
J. Derek Woollins*
Department of Chemistry, University of St Andrews,
St Andrews, Fife, Scotland KY16 9ST
ReceiVed March 9, 1999
We have been studying the coordination chemistry of dithio-
imidodiphosphinates LH since these ligands are related to the
more well-known acac system. Generally, the LH molecules
are readily deprotonated to give L- ligands, which coordinate
with a range of metals to give homoleptic ML2 complexes. We
and others have reported on the interesting geometries at metal
and on the nonplanar six-membered rings.1-4 There have been
some studies on reactions of LH to form copper complexes
which have used Ph2P(S)NHP(S)Ph2 as the ligand. Siiman and
co-workers reported the formation and X-ray characterization
of a Cu4L3 cluster from the reaction of CuII salts with
Ph2P(S)NHP(S)Ph2.5-8 The Cu4L3 core has four copper atoms
in a tetrahedral arrangement with three edges bridged by S donor
atoms from the ligands; the counteranion is [Cu(I)Cl2]-. Further
spectroscopic characterizations have been reported by Naka-
moto.9 The kinetics of the reaction have been studied;10 Bereman
suggested that the reaction proceeds via a CuCl2 species which
could be used as a model or metalloenzymes containing type I
copper(II) centers. The copper(II) species was isolated by
filtering and recrystallizing at -78 °C. The report also contains
ESR spectra which suggest that the geometry at the copper(II)
center is tetrahedral. There are some examples of the Cu3S3
core. Tiethof et al. reported [Cu{(CH3)3PS}Cl]3 in 1973.11 The
Cu3S3 ring in this system was puckered into a chair conforma-
tion. The role of the solvent as the reducing agent was postulated
in a recent paper by Herrmann,12 who obtained [CuI{(C6H5O)2-
P(S)NC(S)N(C2H5)2}]3 with a Cu3S3 core from a reaction in
ethanol using a Cu(II) nitrate salt. Copper(I) species such as
(Ph3P)Cu(SPPh2)2N have also been studied.13 The copper(I) in
this case is three coordinate in a disorted trigonal geometry.
Figure 1. Solid state 31P NMR spectrum of 1.
Here we describe our studies on reactions involving R2P(S)-
i
i
NHP(S)R′2 (R, R′ ) Pr; R ) Pr, R′ ) Ph; R ) EtO, R′ )
OPh) with CuII and CuI chlorides which give trimeric Cu3L3
rings. The X-ray structures of three examples are reported.
Experimental Section
General reaction conditions are as described previously.2 The various
LH systems were prepared as described previously.3,4,14
[CuIN(iPr2PS)2]3 (1). Method 1. CuCl2 (0.10 g 0.45 mmol) was
added to a solution of NH(iPr2PS)2 (0.280 g 0.90 mmol) and KtBuO
(0.1 g 0.089 mmol) in 5 mL of MeOH, and the mixture was stirred for
30 min. The solid purple product was collected by filtration and was
dissolved in dichloromethane. The resulting purple solution was allowed
to evaporate in air to yield a white solid. X-ray quality crystals were
obtained by slow evaporation from dichloromethane. Yield: 0.168 g,
0.122 mmol, 60% (with respect to copper). Microanal. Calcd for
C36H84N3P6S6Cu3: C, 38.3; H, 7.5; N, 3.7. Found: C 38.0; H 6.8; N,
4.0. 31P{1H} NMR (CDCl3): 58.4 ppm. FTIR (KBr disk): ν (PNP)
1229(s); ν (PS) 650(s); δ (NPS) 424(w) cm-1. FAB+ positive MS: m/z
1127 corresponds to product + H+.
Method 2. CuCl (0.099 g 1.0 mmol) was added to a solution of
NH(iPr2PS)2 (0.313 g 1.0 mmol) and KtBuO (0.112 g 1.0 mmol) in 10
mL of MeOH, and the mixture was stirred for 30 min. The white solid
product was collected by filtration. Yield: 0.245 g, 0.217 mmol, 65%
(with respect to copper).
[CuI(EtO)2P(S)NP(S)(OPh)2]3 (2). CuCl2 (0.024 g 0.178 mmol) was
added to a stirring solution of (EtO)2P(S)NHP(S)(OPh)2 (0.150 g 0.364
mmol) and KtBuO (0.041 g 0.364 mmol) in 5 mL of MeOH, and the
mixture was stirred for 30 min. The white product was collected by
filtration. Yield: 0.079 g, 0.055 mmol, 89% (with respect to copper).
Microanal. Calcd for C48H60N3P6O12S6Cu3: C, 40.0; H, 4.2; N, 2.9.
Found: C, 39.7; H, 4.0; N, 3.1. 31P{1H} NMR (CDCl3): 49.6, 43.3
* Author to whom correspondence should be addressed. E-mail:
J.D.Woollins@st-andrews.ac.uk.
(1) Woollins, J. D, J. Chem. Soc., Dalton Trans. 1996, 2893.
(2) Cupertino, D.; Keyte, R.; Slawin, A. M. Z.; Williams, D. J.; Woollins,
J. D. Inorg. Chem. 1996, 35, 2695.
(3) Cupertino, D.; Keyte, R.; Slawin, A. M. Z.; Woollins, J. D. Polyhedron
1998, 17, 4219.
(4) Cupertino, D.; Keyte, R.; Slawin, A. M. Z.; Woollins, J. D. Polyhedron
1998, 18, 311.
(5) Siiman, O.; Huber, C. P.; Post, M. L. Inorg. Chim. Acta 1977, 25,
L11.
(6) Siiman, O.; Huber, C. P.; Post, M. L. Acta Crystallogr. 1978, B34,
2629.
(7) Siiman, O.; Vetuskey, J. Inorg. Chem. 1980, 19, 1672.
(8) Siiman, O. Inorg. Chem. 1981, 20, 2285.
(9) Czernuszewicz, R.; Maslowsky, E.; Nakamoto, K. Inorg. Chim. Acta
1980, 40, 199.
(10) Bereman, R. D.; Wang, F. T.; Najdzionek, J.; Braitsch, D. M. J. Am.
Chem. Soc. 1976, 98, 7266.
2
ppm, J(31P-31P) 39.6 Hz. FTIR (KBr disk): ν (PNP) 1201(s), 1198-
(s); ν (PS) 690(s), 635(s); δ (NPS) 478(w) cm-1. FAB+ positive MS:
m/z 1440 corresponds to product.
[CuI(iPr2P(S)NP(S)Ph2)]3 (3). CuCl2 (0.027 g 0.19 mmol) was added
to a solution of iPr2P(S)NHP(S)Ph2 (0.150 g 0.390 mmol) and KtBuO
(0.044 g 0.390 mmol) in 5 mL of MeOH, and the mixture was stirred
for 30 min. The white product was collected by filtration. Yield: 0.086
g, 0.065 mmol, 96.6% (with respect to copper). Microanal. Calcd for
C54H72N3P6S6Cu3: C, 48.5; H, 5.4; N, 3.2. Found: C, 48.4; H, 5.1; N,
2.7. 31P{1H} NMR (CDCl3): 60.8, 59.2 ppm, 2J(31P-31P) 22.1 Hz. FTIR
(KBr disk): ν (PNP) 1262(s), 1238(s); ν (PS) 699(s), 655(s); δ (NPS)
475(w) cm-1. FAB+ positive MS: m/z 1331 corresponds to product
+ H+.
(11) Tiethof, J. A.;. Stalisk J. K.; Meek, D. W. Inorg Chem. 1973, 12,
1170.
(12) Herrmann, E.; Richter R.; Chau, N. T. T. Z. Anorg. Allg. Chem. 1997,
623, 403.
(13) Haiduc, I.; Cea-olivares, R.; Toscano, R. A.; Silvestru, C. Polyhedron
1995, 14, 1067.
(14) Birdsall, D. J.; Cupertino, D.; Slawin, A. M. Z.; Woollins, J. D. Inorg.
Chim. Acta, in press.
10.1021/ic990276b CCC: $18.00 © 1999 American Chemical Society
Published on Web 08/19/1999

Notes
Inorganic Chemistry, Vol. 38, No. 18, 1999 4153
Table 1. Details of the Crystal Data and Refinements
1
3
4
empirical formula
C36H84N3P6S6Cu3
1127.9
C54H72N3P6S6Cu3
1331.9
C54H72N3O6P6S6Cu3
1427.9
fw
color/size (mm)
clear/0.1 × 0.15 × 0.2
clear/0.14 × 0.18 × 0.3
clear/0.17 × 0.26 × 0.3
cryst syst
triclinic
triclinic
triclinic
space group
P1h (No. 2)
15.299(2)
15.664(2)
14.665(3)
109.29(1)
118.16(1)
94.90(1)
2799
P1h(No. 2)
12.642(1)
18.136(1)
27.899(1)
97.80(1)
94.24(1)
94.09(1)
6288
P1h(No. 2)
10.2234(1)
18.349(1)
18.943(1)
74.35(1)
a
b
c
R
â
87.92(1)
γ
75.35(1)
volume (Å3)
3309
Z
2
4
2
density (calc) g/cm3
1.34
1.39
1.43
µ/mm-1
5.28a
1.39
1.34
F(000)
1188
2760
1476
indep reflns/obs reflns
final R1/wR2c
GOF on F2
8331/6617
0.050/0.049b
3.59b
17870/17820
0.0393/0.083
0.980
9353/9303
0.0368/0.0882
1.015
largest diff peak/hole (e Å-3
)
0.64, -1.05
0.62, -0.52
0.766, -0.502
b
c
2 1/2
a Cu radiation. Refinement on F. R1 ) ∑|Fo| - |Fc|/∑|Fo|. wR2 ) ∑w(|Fo| - |Fc|)2/∑|wFo |
.
Table 2. Selected Bond Lengths (Å) and Angles (deg) in the
Structures of 1, 3, and 4
1
3a
4
Cu(1)-S(1)
Cu(2)-S(3)
Cu(3)-S(5)
Cu(1)-S(2)
Cu(1)-S(6)
Cu(2)-S(2)
Cu(2)-S(4)
Cu(3)-S(4)
Cu(3)-S(6)
P(1)-S(1)
P(3)-S(3)
P(5)-S(5)
P(2)-S(2)
P(4)-S(4)
P(6)-S(6)
P(1)-N(1)
P(3)-N(3)
P(5)-N(5)
P(2)-N(1)
P(4)-N(3)
P(6)-N(5)
2.214(2) 2.2086(13)[2.138(1)3] 2.2188(11)
2.213(2) 2.2072(12)[2.203(13)] 2.2236(11)
2.210(2) 2.2432(13)[2.303(13)] 2.2226(13)
2.257(2) 2.2469(13)[2.2278(14)] 2.2388(11)
2.227(2) 2.2662(12)[2.2505(12)] 2.2815(10)
2.226(1) 2.2105(13)[2.2089(14)] 2.2217(10)
2.253(2) 2.2421(12)[2.2449(12)] 2.2576(10)
2.227(2) 2.2518(11)[2.2536(11)] 2.2425(10)
2.262(2) 2.2862(12)[2.2729(12)] 2.2472(10)
2.010(2) 2.019(2)[2.008(2)]
2.011(2) 2.014(2)[2.014(2)]
2.022(2) 2.011(2)[2.014(2)]
2.033(2) 2.027(2)[2.019(2)]
2.042(2) 2.060(1)[2.057(1)]
2.038(2) 2.046(2)[2.052(2)]
1.591(4) 1.588(3)[1.592(3)]
1.576(4) 1.582(3)[1.584(3)]
1.593(4) 1.600(3)[1.584(3)]
1.585(4) 1.574(3)[1.572(3)]
1.589(4) 1.581(3)[1.581(3)]
1.569(4) 1.574(4)[1.573(3)]
1.9820(14)
1.980(2)
1.964(2)
2.0399(13)
2.0493(13)
2.0516(13)
1.550(3)
1.553(3)
1.538(4)
1.586(3)
1.590(3)
1.586(4)
S(6)-Cu(1)-S(2) 110.88(6) 106.80(5)[111.11(5)]
S(2)-Cu(2)-S(4) 109.94(6) 108.97(5)[108.09(5)]
S(4)-Cu(3)-S(6) 108.67(6) 114.60(4)[112.82(4)]
Cu(1)-S(2)-Cu(2) 124.30(7) 134.15(6)[131.42(6)]
Cu(2)-S(4)-Cu(3) 126.58(7) 102.74(5)[105.05(5)]
Cu(3)-S(6)-Cu(1) 129.67(7) 114.27(5)[110.46(5)]
Cu(1)-S(1)-P(1) 100.98(7) 105.34(6)[100.36(6)]
108.35(4)
108.74(4)
113.32(4)
128.00(5)
108.04(4)
113.54(4)
101.69(5)
S(1)-P(1)-N(1)
P(1)-N(1)-P(2)
N(1)-P(2)-S(2)
120.7(2) 121.21(13)[120.46(14)] 123.45(12)
137.9(3) 141.2(2)[138.1(2)] 144.2(2)
114.6(2) 114.38(14)[114.68(14)] 114.13(12)
P(2)-S(2)-Cu(1) 114.95(8) 108.05(6)[108.12(7)]
S(2)-Cu(1)-S(1) 120.57(6) 118.65(5)[118.17(5)]
Cu(2)-S(3)-P(3) 102.06(8) 100.51(6)[101.42(6)]
106.94(5)
123.82(4)
97.16(5)
S(3)-P(3)-N(3)
P(3)-N(3)-P(4)
N(3)-P(4)-S(4)
119.4(2) 120.16(13)[120.52(13)] 120.91(14)
140.3(3) 141.3(2)[142.1(2)] 136.1(2)
114.6(2) 117.05(13)[115.61(13)] 115.60(12)
Figure 2. X-ray structure of the core geometries in (a) [CuIN(iPr2-
PS)2]3 (1), (b) [CuI(iPr2P(S)NP(S)Ph2)]3 (3), and (c) [CuI(iPr2P(S)NP-
(S)(OPh)2)]3 (4).
P(4)-S(4)-Cu(2) 102.91(7) 102.79(5)[103.82(5)]
S(4)-Cu(2)-S(2) 109.94(6) 108.97(5)[108.09(5)]
Cu(3)-S(5)-P(5) 102.31(7) 100.37(6)99.35(6)
103.10(5)
108.74(4)
100.67(6)
and KtBuO (0.041 g 0.364 mmol) in 5 mL of MeOH, and the mixture
was stirred for 30 min. The white product was collected by filtration.
Yield: 0.078 g, 0.062 mmol, 88% (with respect to copper). Microanal.
Calcd for C54H66N3P6S6Cu3: C, 45.5; H, 4.6; N, 2.9. Found: C, 45.6;
S(5)-P(5)-N(5)
P(5)-N(5)-P(6)
N(5)-P(6)-S(6)
119.2(2) 117.44(14)[118.18(13)] 120.8(2)
139.6(3) 132.3(2)138.5(2)] 138.5(2)
115.1(2) 114.43(14)[115.61(13)] 116.44(14)
P(6)-S(6)-Cu(3) 100.95(7) 97.76(5)[101.60(5)]
104.98(5)
113.32(4)
S(6)-Cu(3)-S(4) 108.67(6) 114.60(4)[112.82(4)]
H, 4.5; N, 2.4. 31P{1H} NMR (CDCl3): 66.3, 38.8 ppm, J(31P-31P)
21.5 Hz. FTIR (KBr disk): ν (PNP) 1202(s), 1196(s); ν (PS) 689(s),
658(s); δ (NPS) 473(w) cm-1. FAB+ positive MS: m/z 1427 corre-
sponds to product + H+.
Crystallography (Table 1) was performed at room temperature (20
°C) using a Rigaku AFC7S diffractometer with Cu KR radiation (λ )
2
a The values in square brackets are for the second independent
molecule, which is numbered sequentially.
[CuI(iPr2P(S)NP(S)(OPh)2)]3 (4). CuCl2 (0.025 g 0.187 mmol) was
i
added to a solution of Pr2P(S)NHP(S)(OPh)2 (0.150 g 0.364 mmol)

4154 Inorganic Chemistry, Vol. 38, No. 18, 1999
Notes
1.541 78 Å) and ω scans for 1 and a Siemens SMART CCD
diffractometer with Mo KR radiation (λ ) 0.710 73 Å) for 3 and 4
where a full hemisphere of data with 0.3° “slices” was collected. A
semiempirical absorption correction based on ψ scans was used for 1
while sadabs15 corrections were applied to 3 and 4. All of the non-H
atoms were refined anisotropically in all three structures. All SMART
structure calculations employed the SHELXTL program system15 while
the refinement for 1 employed teXsan.16 The complete listing of the
crystal data is provided in the Supporting Information.
Results and Discussion
Reaction of CuCl2 or CuCl with R2P(S)NHP(S)R′2/KOtBu
in methanol gives trinuclear copper(I) complexes [CuI(R2P(S)-
NP(S)R′2)]3 in good yield (60-97% with respect to copper
depending on the nature of R). The reaction was carried out
with excess LH: we found that the yield was reduced if we
changed the ratio of reactants. The reaction was also tried with
[(PhO)2P(S)]2NH as the ligand. Several products were produced,
none of which could be suceessfully isolated.
Figure 3. X-ray structure of [CuI(iPr2P(S)NP(S)Ph2)]3 (3).
For the CuII reactions we assume that the reducing agent for
the reaction is the solvent.
There is a related reaction12 for the formation of [CuI-
{(C6H5O)2P(S)NC(S)N(C2H5)2}]3 which also makes use of the
alcohol solvent as a reductant, The trimeric complexes were
characterized spectroscopically and by X-ray crystallography.
All complexes gave satisfactory microanalyses and the ap-
propriate parent ion by FAB MS. Their IR spectra showed the
expected shifts associated with the changes in delocalization
accompanying deprotonation/coordination.2-4 The 31P NMR
data for the unsymmetrical imidophosphinates in 2-4 are simple
AX systems with reasonable 2J(31P-31P) coupling constants (2,
39.6 Hz; 3, 22.1 Hz; 4, 21.5 Hz]. The solid state 31P NMR shows
five peaks with relative intensities of 2:1:1:1:1 (Figure 1) and
at least five independent phosphorus environments. The solution
31P NMR for 1 is a singlet even at low temperature, suggesting
that the molecule is fluxional in solution. The alternative
explanation is that the trimeric system dissociates to monomers
and dimers in solution, but cryoscopic measurements were
inconclusive because of lack of solubility. We did test for this
type of equilibrium by stirring mixtures of 1 with 4 to test for
“scrambling” of the ligands. Over a period of 5 days no such
mixing was observed. Similarly stirring 1 with a range of other
dithioimidophosphinates did not result in ligand exchange. Some
preliminary electrochemical studies were carried out on 1; CV
studies showed an irreversible oxidation reaction, but again
solubility in the electrolyte solution hindered any detailed
measurements.
Figure 4. X-ray structure of [CuI(iPr2P(S)NP(S)(OPh)2)]3 (4).
approximately trigonal geometry as a result of two bridging and
one terminal sulfur donor atoms. Generally it appears that the
two-coordinate sulfur atoms have slightly shorter Cu-S and
P-S bond lengths than the three-coordinate sulfur atoms though
the statistical significance of some individual distances is slight.
The most noticeable difference is that the P-S bond lengths
associated with the OPh-substituted phosphorus atoms in 4 are
substantially shorter than those at Ph- or Pr-substituted phos-
phorus atoms in any of the structures. This effect is also
statistically significant for the P-N bond lengths, which are
slightly shorter for the P(OPh)2 centers than elsewhere. The
Cu3S3 rings are similar in all three structures but do display
differences in conformation; in 1 this core is close to planar
[mean deviation 0.16 Å, maximum deviation 0.31 Å for Cu-
(2)] and the core in 3 is puckered in a “half-chair” conformation
while the core in 4 has a pseudo boat conformation. The intra-
ring S-Cu-S and Cu-S-Cu angles lie in the ranges 108.67-
(6)-114.60(4)° and 102.74(5)-134.15(6)°, respectively. The
six-membered CuS2P2N rings are not perfectly symmetric and
display a range of geometries such as planar, boat, and chair as
has been observed previously.1 The Cu-S-P and S-P-N
angles are in the ranges 97.15(5)-114.95(8)° and 114.43(4)-
123.45(12)°, respectively, while the N-P-N angles lie between
137.9(3)° and 144.2(2)°. In the structures of 3 and 4 it is possible
to envisage a number of possible isomers though there was no
The X-ray structures of 1, 3, and 4 (Table 2, Figures 2 and
3) reveal that the molecules contain a six-membered Cu3S3 ring
in their core with each copper atom being tricoordinate in
(15) SHELXTL; Bruker AXS: Madison, NY, 1998.
(16) teXsan; Molecular Structure Corporation: The Woodlands, TX, 1996.

Notes
Inorganic Chemistry, Vol. 38, No. 18, 1999 4155
evidence for this from NMR studies. In 4 we observe the
“symmetric” isomer which has pseudo-3-fold symmetry about
an axis running through the center of the Cu3S3 ring while in 3
one of the ligands is reversed, resulting in loss of symmetry.
We speculate that the weaker donor ability of a (PhO)2PdS
group relative to a (Ph)2PdS group limits the ability of the
phenoxy system to use its sulfur atom for bridging within the
Cu3S3 ring while this is not a significant constraint for the phenyl
system; there do not appear to be any steric constraints to any
isomer formation. X-ray examination of several crystals and
the bulk material revealed no evidence of any other isomers
in 3.
Acknowledgment. We are grateful to Zeneca for support,
to the JREI for an equipment grant, and to M. Davidson
(Durham) for cryoscopy.
Supporting Information Available: Three tables giving experi-
mental crystallographic details, bond lengths, bond angles, and aniso-
tropic displacement parameters for non-hydrogen atoms for 1, 3 (two
independent molecules), and 4. This material is available free of charge
via the Internet at http://pubs.acs.org.
IC990276B