Bis[(diphenylsulfimido)triphenylphosphonium] di-μ-bromo- bis[dibromopalladate(II)]

Article abstract of DOI:10.1107/S0108270104029464

The title compound, (C₃₀H₂₅NPS)₂[Pd ₂Br₆] or (Ph₃PNSPh₂) ₂-[Pd₂Br₆], was crystallized from the reaction of (Ph₃PNSPh₂)-[BPh₄] with (PPh ₄)₂[Pd₂Br₆], giving a salt rather than the intended coordination complex [PdBr₃(Ph ₃PNSPh₂)]. The compound crystallizes in the non-centrosymmetric space group Cc with one complete formula unit in the asymmetric unit. One of the two independent cations is disordered. The geometry of the two cations is compared with that of the only previously crystallized example of this cation, viz. its [SbCl₆]^- salt [Reck et al. (1982). Chem. Ber. 115, 2981-2996]. The bond angles within the P-N-S triad in the two cations in the title compound are narrower than those observed in the literature example, while the S-N bond lengths are slightly longer in the title compound. The P-N bond length in the ordered cation shows excellent agreement with that determined by Reck and co-workers, but the P-N bond lengths are lengthened slightly in the disordered cation. Weak C-H...Br interactions create a three-dimensional network, with cations and anions alternating along the crystallographic c direction.

Full text of DOI:10.1107/S0108270104029464

metal-organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
charge, which may hamper their ability to coordinate to a
metal centre. In order to start to address this question we have
undertaken the reaction between (Ph3PNSPh2)[BPh4] and
(PPh4)2[Pd2Br6] in order to generate (Ph3PNSPh2)2[Pd2Br6] as
the initial product by metathesis. Previous work has shown
that the [Pd2Br6]2 anion is a very effective source of the
coordinatively unsaturated [PdBr3] unit, which can then
coordinate to a range of main-group species (e.g. Kelly et al.,
ISSN 0108-2701
Bis[(diphenylsulfimido)triphenyl-
phosphonium] di-l-bromo-bis[di-
bromopalladate(II)]
+
1995). If the Ph3PNSPh2 cation is capable of acting as a
reasonably effective ligand, then previous experience would
indicate that subsequent formation of [PdBr3(Ph3PNSPh2)]
could be expected, the positive charge on the incoming unit
being offset by the fact that the [PdBr3] unit is negatively
charged, thereby providing some electrostatic encouragement
to the reaction.
Sophie H. Dale, Mark R. J. Elsegood, Liam M. Gilby,
Kathryn E. Holmes and Paul F. Kelly*
Chemistry Department, Loughborough University, Leicestershire LE11 3TU, England
Correspondence e-mail: p.f.kelly@lboro.ac.uk
Received 4 November 2004
Accepted 12 November 2004
Online 11 December 2004
The title compound, (C30H25NPS)2[Pd2Br6] or (Ph3PNSPh2)2-
[Pd2Br6], was crystallized from the reaction of (Ph3PNSPh2)-
[BPh4] with (PPh4)2[Pd2Br6], giving a salt rather than the
intended coordination complex [PdBr3(Ph3PNSPh2)]. The
compound crystallizes in the non-centrosymmetric space
group Cc with one complete formula unit in the asymmetric
unit. One of the two independent cations is disordered. The
geometry of the two cations is compared with that of the only
previously crystallized example of this cation, viz. its [SbCl6]
salt [Reck et al. (1982). Chem. Ber. 115, 2981±2996]. The bond
angles within the PÐNÐS triad in the two cations in the title
compound are narrower than those observed in the literature
example, while the SÐN bond lengths are slightly longer in
the title compound. The PÐN bond length in the ordered
cation shows excellent agreement with that determined by
Reck and co-workers, but the PÐN bond lengths are
lengthened slightly in the disordered cation. Weak CÐHÁ Á ÁBr
Crystallization of the product of the reaction results in
orange crystals for which X-ray crystallography reveals the
structure (Ph3PNSPh2)2[Pd2Br6], (I), i.e. the simple salt rather
than the coordination complex [PdBr3(Ph3PNSPh2)]. The
asymmetric unit contains one complete formula unit of (I)
(Fig. 1). One of the two independent Ph3PNSPh2+ cations was
found to be disordered, and the S and N atoms and the two
phenyl rings bonded to atom S2 were modelled as disordered
over two sets of positions (see Experimental). The two cations
interactions create
a three-dimensional network, with
cations and anions alternating along the crystallographic c
direction.
Comment
It has been known for some time that the bromosulfimide
Ph2SNBr is capable of undergoing oxidative addition to simple
phosphines and sul®des to generate cations such as
+
+
Ph3PNSPh2 and Ph2SNSPh2 (Furukawa et al., 1978). In
recent work, we have demonstrated that such reactions may
be extended to polyphosphines and selenides, and we have
used X-ray crystallography to characterize the novel [1,4-
(Ph2PNSPh2)2(C6H4)]2+ and Ph2SNSPh2 cations (Aucott et
+
al., 2004). In the light of the relative ease of preparation and
stability of such compounds, and given our ability to include a
variety of main-group atoms within the basic XÐNÐY core,
the question of the ability of these cations to act as ligands
becomes relevant. The presence of the three potential donor
sites is offset by the fact that the units possess a positive
Figure 1
A view of the components of (I), showing the atom-labelling scheme.
Displacement ellipsoids are drawn at the 50% probability level, and H
atoms and the minor disorder component have been omitted for clarity.
m40 # 2005 International Union of Crystallography
DOI: 10.1107/S0108270104029464
Acta Cryst. (2005). C61, m40±m42

metal-organic compounds
Data collection
have very similar geometries (Table 1), and compare well with
the geometry of the same cation in the structure of
(Ph3PNSPh2)[SbCl6]ÁCH2Cl2 (Table 3) (Reck et al., 1982).
There are small differences between the geometric parameters
of the cations in (I) and those in Table 3; clearly the PÐNÐS
bond angle is narrower in both cations present in (I)
(including the disordered group) and the SÐN bond lengths
are slightly longer than that in the literature compound. The
PÐN bond lengths in the second (disordered) cation in (I) are
lengthened compared with the ordered cation in (I) and the
literature compound. It should be noted here that restraints
were only applied to the geometries of the partially occupied
phenyl components of the disordered group, but not to the PÐ
N or SÐN bond lengths or to the PÐNÐS geometry.
Bruker SMART 1000 CCD
diffractometer
! scans
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
Tmin = 0.104, Tmax = 0.168
24 282 measured re¯ections
12 979 independent re¯ections
11 006 re¯ections with I > 2ꢄ(I)
Rint = 0.032
ꢂmax = 27.5ꢁ
h = 16 ! 16
k = 21 ! 21
l = 37 ! 36
Re®nement
Re®nement on F2
R[F2 > 2ꢄ(F2)] = 0.036
wR(F2) = 0.082
w = 1/[ꢄ2(F2o) + (0.029P)2]
where P = (F2o + 2Fc2)/3
(Á/ꢄ)max = 0.001
3
Ê
S = 1.01
Áꢅmax = 1.29 e A
3
Ê
0.90 e A
12 639 re¯ections
732 parameters
H-atom parameters constrained
Áꢅmin
=
Absolute structure: Flack (1983),
5943 Friedel pairs
Flack parameter = 0.065 (6)
Owing to the large number of relatively acidic aryl CH
groups, the presence of CÐHÁ Á ÁBr interactions (Table 2) is
unsurprising. These interactions have CÁ Á ÁBr distances in the
Table 1
Selected geometric parameters (A, ).
ꢁ
Ê
ꢁ
Ê
Pd1ÐBr1
Pd1ÐBr2
Pd1ÐBr3
Pd1ÐBr4
Pd2ÐBr3
Pd2ÐBr4
Pd2ÐBr5
Pd2ÐBr6
S1ÐN1
2.4102 (7)
2.4086 (7)
2.4550 (7)
2.4437 (7)
2.4505 (7)
2.4455 (7)
2.4180 (7)
2.4109 (7)
1.616 (4)
1.778 (4)
1.796 (5)
1.609 (4)
P1ÐC13
P1ÐC19
P1ÐC25
P2ÐN2
P2ÐN2X
P2ÐC43
P2ÐC49
P2ÐC55
S2ÐN2
1.808 (6)
1.786 (5)
1.787 (5)
1.622 (5)
1.63 (3)
1.803 (5)
1.797 (6)
1.785 (5)
1.615 (5)
1.789 (5)
1.795 (5)
range ꢀ3.8±3.9 A and CÐHÁ Á ÁBr angles greater than 140 ;
Ê
these ranges compare well with the mean value of 3.75 (2) A
for CÁ Á ÁBr contact distances in Csp2ÐHÁ Á ÁBr interactions
having CÐHÁ Á ÁBr angles greater than 140ꢁ (Desiraju &
Steiner, 1999). These weak interactions create a three-
dimensional network, with cations and anions alternating
along the crystallographic c direction.
S1ÐC1
S1ÐC7
P1ÐN1
S2ÐC31
S2ÐC37
The fact that the cation has not broken into the structure of
the bromo-bridged palladium dimer is indicative of the poor
donor capabilities of the cation. Of course, this result does not
entirely rule out coordination by such species and future work
will investigate their reactivity towards other complexes
bearing labile ligands. It may prove necessary to use low valent
metal reagents such as Pt0, which could induce concomitant
reduction of the cations and the formation of anionic species
more conducive to coordination, in this case to the resulting
PtII centre. Indeed, the question of the nature of the reduction
products of such heteronuclear cations is intriguing, and work
to assess this process is underway.
P1ÐN1ÐS1
118.1 (3)
P2ÐN2ÐS2
119.1 (3)
Table 2
Hydrogen-bonding geometry (A, ).
ꢁ
Ê
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
C14ÐH14Á Á ÁBr6i
C17ÐH17Á Á ÁBr2ii
C27ÐH27Á Á ÁBr3iii
C39ÐH39Á Á ÁBr6iv
C59ÐH59Á Á ÁBr4v
0.95
0.95
0.95
0.95
0.95
3.13
2.97
2.93
2.92
2.93
3.909 (6)
3.900 (7)
3.858 (6)
3.827 (8)
3.830 (6)
140
167
167
161
158
1
2
3
2
1
2
1
2
Symmetry codes: (i) x 1; y; z; (ii) x
1
;
y; z 12; (iii) x
;
‡ y; z; (iv) x 1;
y; 12 ‡ z; (v) x 21; y 12; z.
Experimental
Table 3
(Ph3PNSPh2)Br was prepared by the reaction of Ph2SNBr with PPh3
in toluene in the same manner as the bisphosphine reactions
described by Aucott et al. (2004). (Ph3PNSPh2)[BPh4] was then
precipitated from a methanol solution of (Ph3PNSPh2)Br by addition
of Na[BPh4]. (Ph3PNSPh2)[BPh4] and (PPh4)2[Pd2Br6] were reacted
in MeCN, producing a precipitate of (PPh4)[BPh4]. The ®ltrate was
evaporated to dryness and redissolved in dichloromethane, and the
title product was crystallized by diffusion of diethyl ether into this
solution.
ꢁ
Ê
Selected bond lengths and angle (A, ) for (Ph2SNPPh3)[SbCl6]ÁCH2Cl2
(Reck et al., 1982).
SÐN
PÐN
1.596
1.608
SÐC
PÐC
1.755, 1.761
1.779, 1.788, 1.797
PÐNÐS
123.6
The data set for (I) was truncated at 2ꢂ = 55ꢁ, as only statistically
insigni®cant data were present above this limit. Atoms N2 and S2 and
the phenyl substituents bonded to atom S2 were found to be disor-
dered. These groups were modelled over two sets of positions, giving
a re®ned major occupancy of 88.5 (3)%. The C atoms in the minor
component of the disorder model were re®ned isotropically, with
restraints applied to their displacement parameters. Atoms N2X and
S2X were re®ned anisotropically, with restraints applied to their
displacement parameters. Restraints were also applied to the
geometries of the phenyl substituents in the disordered group. The
Crystal data
3
(C30H25NPS)2[Pd2Br6]
Mr = 1617.34
Monoclinic, Cc
Dx = 1.815 Mg m
Mo Kꢁ radiation
Cell parameters from 12 077
re¯ections
Ê
Ê
a = 12.8250 (13) A
b = 16.2000 (16) A
ꢂ = 2.2±28.5ꢁ
ꢃ = 4.82 mm
T = 150 (2) K
1
Ê
c = 28.721 (3) A
ꢀ = 97.318 (2)ꢁ
V = 5918.7 (10) A
Z = 4
3
Ê
Block, dark orange
0.59 Â 0.40 Â 0.37 mm
ꢂ
Acta Cryst. (2005). C61, m40±m42
Sophie H. Dale et al.
(C30H25NPS)2[Pd2Br6] m41

metal-organic compounds
Ê
largest ÁF residual lies 1.03 A from atom Pd1. H atoms were posi-
Ê
tioned geometrically (CÐH = 0.95 A) and re®ned using a riding
model, with Uiso(H) = 1.2Ueq(C).
References
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Â
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(Bruker, 2001); data reduction: SAINT; program(s) used to solve
structure: SHELXTL (Sheldrick, 2000); program(s) used to re®ne
structure: SHELXTL; molecular graphics: SHELXTL; software used
to prepare material for publication: SHELXTL and local programs.
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The authors acknowledge the EPSRC for postdoctoral
support (LMG) and Johnson Matthey for loans of precious
metals.
Sheldrick, G. M. (2000). SHELXTL. Version 6.10. Bruker AXS Inc., Madison,
Wisconsin, USA.
È
Sheldrick, G. M. (2003). SADABS. Version 2.10. University of Gottingen,
Germany.
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: BM1597). Services for accessing these data are
described at the back of the journal.
ꢂ
m42 Sophie H. Dale et al.
(C30H25NPS)2[Pd2Br6]
Acta Cryst. (2005). C61, m40±m42