Synthesis and characterization of RuII/AuI, PdII/AuI, PdII/2AuI, PtII/2AuI and CuI/2AuI heterometallic complexes of cyclodiphosphazane cis-{(o-Me

Article abstract of DOI:10.1016/j.poly.2007.08.024

Mononuclear complexes of cyclodiphosphazane with an uncoordinated phosphorus centre [RuCl₂(η⁶-cymene){l-κP}] (1a) (L = cis-{(o-MeOC₆H₄O)P(μ-N^tBu)}₂) and [PdCl₂(PEt₃){l

Full text of DOI:10.1016/j.poly.2007.08.024

Available online at www.sciencedirect.com
Polyhedron 27 (2008) 80–86
www.elsevier.com/locate/poly
Synthesis and characterization of RuII/AuI, PdII/AuI, PdII/2AuI,
PtII/2AuI and CuI/2AuI heterometallic complexes
of cyclodiphosphazane cis-{(o-MeOC6H4O)P(l-NtBu)}2
a
b
a,
*
P. Chandrasekaran , Joel T. Mague , Maravanji S. Balakrishna
a
Phosphorus Laboratory, Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400 076, India
b
Department of Chemistry, Tulane University, New Orleans, Louisiana, LA 70118, USA
Received 7 August 2007; accepted 22 August 2007
Available online 25 September 2007
Abstract
Mononuclear complexes of cyclodiphosphazane with an uncoordinated phosphorus centre [RuCl2(g6-cymene){L-jP}] (1a)
(L = cis-{(o-MeOC6H4O)P(l-NtBu)}2) and [PdCl2(PEt3){L-jP}] (1b) react with 1 equiv. of [AuCl(SMe2)] to afford RuII/AuI and PdII/
AuI heterodinuclear complexes [RuCl2(g6-cymene){l-L-jP,jP}AuCl] (2) and [PdCl2(PEt3){l-L-jP,jP}AuCl] (3), respectively. Heterotri-
nuclear complexes [PdCl2{l-L-jP,jP}2(AuCl)2] (4), [PtCl2{l-L-jP,jP}2(AuCl)2] (5) and [CuI{l-L-jP,jP}2(AuCl)2] (6) containing PdII/
2AuI, PtII/2AuI and CuI/2AuI metal centers have been synthesized from the reactions of trans-[PdCl2{L-jP}2] (1c), cis-[PtCl2{L-jP}2]
(1d) and [CuI{{L-jP}2] (1f) respectively, with 2 equiv. of [AuCl(SMe2)]. Molecular structures of complexes 2, 3 and 4 were established
by single crystal X-ray diffraction studies.
ꢀ 2007 Elsevier Ltd. All rights reserved.
Keywords: Cyclodiphosphazanes; Heterometallic complexes; Mono- and bidentate coordination; Crystal structures
1. Introduction
tive of the stoichiometry and the reaction conditions. In
contrast, reactions with [Rh(CO)2Cl]2, [PdCl(g3-C3H5)]2,
CuX (X = Cl, Br, I), AgOTf and AuCl(SMe2) afforded
complexes with ligand exhibiting both monodentate and
bridged bidentate coordination modes. The bridging coor-
dination mode of the cyclodiphosphazane leads to the
formation of novel metallamacrocycles (RhI, AuI) and
one dimensional coordination polymers (CuI and AgI).
The monodentate coordination of the cyclodiphosphazane
leads to the complex having a free PIII site for further
coordination. This interesting coordination behavior of
cis-[(o-MeOC6H4O)P(l-NtBu)]2 can be utilized for the
syntheses of numerous hetero-multinuclear complexes
containing two or more different late transition metals.
Heterometallic complexes containing two different early
or late transition metals are difficult to synthesize due to
the similar reactivity of late metals toward symmetrical
ligands, whilst late-early heterometallic (LEHM) com-
plexes can be conveniently prepared using amide or alkoxy
functionalized phosphine ligands due to the preference of
Over the past decade cyclodiphosphazanes have been
extensively used for the syntheses of several phosphorus–
nitrogen macrocycles and cages [1]. Stahl and Chivers
utilized amide substituted cyclodiphosphazanes of the type
cis-[(tBuNH)P(E)(l-NtBu)]2 (E = lone pair, O, S, Se) to
stabilize various main group and transition metals [2].
Earlier reports on the coordination chemistry of cyclodi-
phosphazanes were limited to group-6 and 10 metals [3].
Recently we investigated [4] the coordination behavior of
the cyclodiphosphazane cis-[(o-MeOC6H4O)P(l-NtBu)]2
with various transition metal reagents and observed the
cis-[(o-MeOC6H4O)P(l-NtBu)]2 ligand selectively forming
mononuclear complexes with metal reagents such as
[RuCl2(g6-cymene)]2, [MCl(COD)]2 (M = Rh, Ir), [PdCl2-
(PEt3)]2, [MCl2(COD)] (M = Pd, Pt) and AgCN irrespec-
*
Corresponding author. Tel.: +91 22 2576 7181; fax: +91 22 2572 3480.
E-mail address: krishna@chem.iitb.ac.in (M.S. Balakrishna).
0277-5387/$ - see front matter ꢀ 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2007.08.024

P. Chandrasekaran et al. / Polyhedron 27 (2008) 80–86
81
early metals for hard centers and late metals for soft metal
centers [5]. Heterometallic complexes containing platinum
metals which are far apart with out metal–metal interac-
tions can be utilized as one pot catalysts to promote more
than one type of catalytic reaction [6]. In this context, we
report the syntheses of RuII/AuI, PdII/AuI, PdII/2AuI,
PtII/2AuI and CuI/2AuI heterometallic complexes
anchored by the cyclodiphosphazane, cis-[(o-MeOC6H4O)-
P(l-NtBu)]2 and also the molecular structures of RuII/AuI,
PdII/AuI, PdII/2AuI heterometallic derivatives.
(1b) (48.7 mg, 0.065 mmol) also in dichloromethane at
room temperature. The resulting reaction mixture was stir-
red for 4 h, concentrated to 5 mL and diluted with 5 mL
CH3CN. Slow evaporation of CH2Cl2 from this solution
at room temperature yielded the product as yellow crystals
(58.6 mg, 92%). M.p.: 218–220 ꢁC (dec). Anal. Calc. for
C28H47N2O4P3PdAuCl3: C, 34.37; H, 4.84; N, 2.86. Found:
1
C, 34.56; H, 4.98; N, 2.79%. H NMR (400 MHz; CDCl3,
25 ꢁC): dH = 7.05–6.84 (m, 8H, Ph), 3.87 (s, 3H, OMe),
3.79 (s, 3 H, OMe), 2.27 (m, 2H, CH2), 1.55 (s, 18H,
tBu), 1.26 (m, 3H, CH3) ppm. 31P{1H} NMR
2
2. Experimental
(161.9 MHz, CDCl3, 25 ꢁC): dP = 108.9 (d, JPP = 39 Hz,
2
1P, AuP), 83.8 (dd, 1P, PdP), 30.2 (d, JPP = 16 Hz, 1P,
All experimental manipulations were carried out
under an atmosphere of dry nitrogen using Schlenk tech-
niques. Solvents were dried and distilled prior to use by
conventional methods [7]. The compounds [RuCl2-
(g6-cymene){l-L-jP}] (1a), [PdCl2(PEt3){l-L-jP}] (1b),
trans-[PdCl2{l-L-jP}2] (1c), cis-[PtCl2{l-L-jP}2] (1d) [4b],
[CuI{l-L-jP}2] (1e) [4c] (L = cis-{(o-MeOC6H4O)P-
(l-NtBu)}2) and [AuCl(SMe2)] [8] were prepared according
to the published procedures.
PdPEt3) ppm. MS(EI, m/z): 942.76 (M–Cl).
2.3. Synthesis of [PdCl2{l-L-jP,jP}2(AuCl)2] (4)
A dichloromethane solution (7 mL) of [AuCl(SMe2)]
(48.1 mg, 0.164 mmol) was added dropwise to a well-stirred
dichloromethane solution (10 mL) of trans-[PdCl2-
{l-L-jP}2] (1c) (88.3 mg, 0.082 mmol) at room tempera-
ture. The yellow reaction mixture was stirred at room
temperature for 4 h, concentrated to 10 mL under reduced
pressure and diluted with 5 mL of CH3CN. Storage at
room temperature for 3 days afforded the product as yellow
crystals (110 mg, 87%). M.p.: 206–208 ꢁC (dec). Anal. Calc.
for C44H64N4P4O8PdAu2Cl4: C, 34.24; H, 4.18; N, 3.63.
1
The H and 31P{1H} NMR spectra were recorded using
Varian Mercury Plus spectrometer operating at the appro-
priate frequencies using TMS and 85% H3PO4 as internal
and external references, respectively. Microanalyses were
performed on a Carlo Erba Model 1112 elemental ana-
lyzer. Mass spectrometry experiments were carried out
using Waters Q-Tof micro-YA-105. Melting points were
recorded in capillary tubes and are uncorrected.
1
Found: C, 34.48; H, 4.27; N, 3.44%. H NMR (400 MHz;
CDCl3, 25 ꢁC): dH = 8.04–6.83 (m, 16 H, Ph), 3.88 (s, 6H,
OMe), 3.86 (s, 6H, OMe), 1.63 (s, 36H, tBu) ppm.
31P{1H} NMR (161.9 MHz, CDCl3, 25 ꢁC): dP = 105.0
2.1. Synthesis of [RuCl2(g6-cymene){l-L-jP,jP}AuCl]
(2)
(d, JPP = 40 Hz, 1P, PAu), 70.5 (d, 1P, PPd) ppm.
2
2.4. Synthesis of [PtCl2{l-L-jP,jP}2(AuCl)2] (5)
A dichloromethane (7 mL) solution of [AuCl(SMe2)]
(20.2 mg, 0.069 mmol) was added dropwise to [RuCl2-
(g6-cymene){l-L-jP}] (1a) (52.3 mg, 0.069 mmol) in CH2Cl2
(5 mL) at room temperature with stirring. Stirring was con-
tinued for 6 h with minimum light exposure. The reaction
mixture was concentrated to 5 mL under reduced pressure
and to this was added 3 mL of hexane. Storage at À30 ꢁC
for one day afforded the product as dark orange crystals
(52.5 mg, 77%). M.p.: 170–172 ꢁC (dec). Anal. Calc. for
C32H46N2P2O4Cl3RuAu: C, 38.85; H, 4.68; N, 2.83.
A dichloromethane solution (7 mL) of [AuCl(SMe2)]
(22.1 mg, 0.079 mmol) was added dropwise to a well-stirred
dichloromethane solution (5 mL) of cis-[PtCl2{l-L-jP}2]
(1d) (43.7 mg, 0.037 mmol) at room temperature. The reac-
tion mixture was stirred for 4 h, concentrated to 5 mL and
diluted with 3 mL of hexane. Storage at À30 ꢁC for one day
afforded a white crystalline product (41.1 mg, 68%). M.p.:
224–226 ꢁC (dec). Anal. Calc. for C44H64N4O8P4Au2PtCl4:
C, 32.38; H, 3.95; N, 3.43. Found: C, 32.55; H, 4.12; N,
1
1
Found: C, 38.59; H, 4.71; N, 3.05%. H NMR (400 MHz;
3.77%. H NMR (400 MHz; CDCl3, 25 ꢁC): dH = 7.74–
CDCl3, 25 ꢁC): dH = 7.26–6.90 (m, 8H, Ph), 5.47 (d,
6.82 (m, 16 H, Ph), 3.87 (s, 6H, OMe), 3.83 (s, 6H,
i
i
t
JHH = 6 Hz, 2H, MeC6H4 Pr-p), 5.34 (d, 2H, MeC6H4 Pr-
OMe), 1.45 (s, 36 H, Bu) ppm. 31P{1H} NMR (161.9
3
p), 3.85 (s, 3H, OMe), 3.86 (s, 3H, OMe), 2.92 (sep, 1H,
MHz, CDCl3, 25 ꢁC): dP = 109.4 (d, JPtP = 81 Hz, 2P,
t
1
2
CH), 2.16 (s, 3H, Me), 1.54 (s, 18H, Bu), 1.28 (d, JHH
=
AuP), 47.0 (d, JPtP = 5738 Hz, JPP = 36 Hz, 2P, PtP)
6.8 Hz, 6H, CMe2) ppm. 31P{1H} NMR (161.9 MHz,
CDCl3, 25 ꢁC): dP = 129.3 (s, 1P, PRu), 105.3 (s, 1P,
PAu) ppm.
ppm.
2.5. Synthesis of [CuI{l-L-jP,jP}2(AuCl)2] (6)
2.2. Synthesis of [PdCl2(PEt3){l-L-jP,jP}AuCl] (3)
A solution of [AuCl(SMe2)] (46.3 mg, 0.157 mmol) in
7 mL of CH2Cl2 was added dropwise to a well-stirred
CH2Cl2 (5 mL) solution of [CuI{l-L-jP}2] (1e) (85.3 mg,
0.078 mmol) at room temperature. The colorless reaction
[AuCl(SMe2)] (19.2 mg, 0.065 mmol) dissolved in 5 mL
of dichloromethane was added to [PdCl2(PEt3){l-L-jP}]

82
P. Chandrasekaran et al. / Polyhedron 27 (2008) 80–86
tBu
tBu
mixture was stirred for 4 h, concentrated to 5 mL under
reduced pressure and diluted with 3 mL of hexane. Storage
at À30 ꢁC for one day afforded the product as a white crys-
talline solid (84.9 mg, 70%). M.p.: 194–196 ꢁC (dec). Anal.
Calc. for C44H64N4O8P4CuAu2ICl2: C, 33.95; H, 4.14; N,
3.60. Found: C, 33.74; H, 4.06; N, 3.72%. 1H NMR
(400 MHz; CDCl3, 25 ꢁC): dH = 7.89–6.73 (m, 16H, Ph),
R
R
R
R
N
N
[AuCl(SMe2)]
CH2Cl2
Cl
P
P
P
P
Cl
N
N
Ru
Ru
tBu
tBu
Au
Cl
Cl
1a
Cl
2
[R = OC6H4Me-o]
t
3.85 (s, 6H, OMe), 3.77 (s, 6H, OMe), 1.52 (s, 36H, Bu)
Scheme 1. Synthesis of RuII/AuI complex.
ppm. 31P{1H} NMR (161.9 MHz, CDCl3, 25 ꢁC):
dP = 120.9 (br s, 2P, CuP), 105.9 (s, 2P, AuP) ppm.
complex [RuCl2(g6-cymene){l-L-jP,P}AuCl] (2) was
synthesized by treating 1a with 1 equiv. of [AuCl(SMe2)]
in dichloromethane as shown in Scheme 1. The 31P NMR
spectrum of 2 exhibits two single resonances at 129.3 and
105.3 ppm, respectively, for ruthenium and gold coordi-
nated phosphorus centers of the cyclodiphosphazane. Sur-
prisingly, no 2JPP coupling was observed although complex
2.6. X-ray crystallography
Crystals of 2, 3 and 4 were mounted in a CryoLoop with
a drop of Paratone oil and placed in the cold nitrogen
stream of the Kryoflex attachment of the Bruker APEX
CCD diffractometer. Full spheres of intensity data were
collected for each crystals as three sets of 400 scans in x
(0.5ꢁ per scan at / = 0ꢁ, 90ꢁ and 180ꢁ) and two sets of
800 scans in / (0.45ꢁ per scan at x = À30ꢁ and 210ꢁ).
Intensity data were collected using the SMART software
package [9] and these were reduced to F2 values with the
SAINT+ software [10] which also performed a global refine-
ment of unit cell parameters using 9217 (for 2), 9275 (for 3)
and 8300 (for 4) reflections chosen from the full data set.
Crystals of 2 and 3 proved to be twinned and the integra-
tion of the raw data was carried out with the two-compo-
nent version of SAINT+ using the two-component
orientation file prepared by CELL_NOW [11] and with the cell
parameters of the second domain of the twin constrained to
be identical to those of the first domain. Multiple measure-
ments of equivalent reflections provided the basis for
empirical absorption corrections as well as corrections
for any crystal deterioration during the data collection
(TWINABS [12] for 2 and 3 and SADABS [13] for 4). The
structures were solved by direct methods and refined by
full-matrix least-squares procedures using the SHELXTL
program package [14]. Hydrogen atoms were placed in
2
1a shows a JPP coupling of 8.7 Hz.
Addition of 1 equiv. of [AuCl(SMe2)] to a dichlorometh-
ane solution of [PdCl2(PEt3){l-L-jP}] (1b) results in the
formation of
a
PdII/AuI heterobimetallic complex
[PdCl2(PEt3){l-L-jP,jP}AuCl] (3) in quantitative yield
(Scheme 2). The 31P NMR spectrum of 3 exhibits three sig-
nals due to the presence of three P-centers. The phospho-
rus-31 resonance corresponding to the Au-coordinated
2
centre appears as a doublet at 108.9 ppm, with a JPP cou-
pling of 39 Hz, whereas the Pd-bound phosphorus of the
cyclodiphosphazane appears as a doublet of doublets cen-
tered at 83.8 ppm due to the coupling with two different
neighboring phosphorus centers. The signal corresponding
2
to PEt3 appears as a doublet at 30.2 ppm with a Jpp cou-
pling of 16 Hz.
The reaction of 2 equiv. of cis-{(o-MeOC6H4O)P-
(l-NtBu)}2 with [PdCl2(NCPh)2] or [PdCl2(SMe2)2] afforded
trans-[PdCl2{l-L-jP}2] (1c) exclusively [4b]. The molecular
structure of 1c reveals the trans arrangement of two
cyclodiphosphazanes with two uncoordinated PIII centers
˚
calculated positions (C–H = 0.95 A (aromatic rings) or
˚
0.98 A (methyl groups)) and included as riding contribu-
tBu
tBu
R
R
R
R
tions with isotropic displacement parameters 1.2 (aromatic
rings) or 1.5 (methyl groups) times those of the attached
non-hydrogen atoms.
N
N
[AuCl(SMe2)]
CH2Cl2
PEt3
Cl
PEt3
Cl
P
P
P
P
N
N
Pd
Pd
tBu
tBu
Au
Cl
Cl
Cl
1b
3
3. Results and discussion
[R = OC6H4Me-o]
Scheme 2. Synthesis of PdII/AuI complex.
3.1. Synthesis of heterometallic complexes
Mononuclear RuII and PdII complexes [RuCl2(g6-cyme-
ne){l-L-jP}] (1a) and [PdCl2(PEt3){l-L-jP}] (1b) contain-
ing one uncoordinated PIII site were prepared from the
reaction of cis-{(o-MeOC6H4O)P(l-NtBu)}2 (L) with
[RuCl2(g6-cymene)]2 and [PdCl2(PEt3)], respectively [4b].
Interestingly, the cyclodiphosphazane cis-{(o-MeO-
C6H4O)P(l-NtBu)}2 afforded exclusively the mononuclear
derivatives 1a and 1b, irrespective of the reaction condi-
tions and stoichiometry. The RuII/AuI heterobimetallic
tBu
tBu
R
R
R
R
N
N
P
Cl
Cl
P
P
P
Cl
P
2 [AuCl(SMe2)]
CH2Cl2
tBu
tBu
N
Au
N
Pd
Au
tBu
Pd
tBu
N
N
Cl
Cl
P
P
Cl
P
N
N
R
R
tBu
R
R
tBu
4
1c
[R = OC6H4Me-o]
Scheme 3. Synthesis of PdII/2AuI complex.

P. Chandrasekaran et al. / Polyhedron 27 (2008) 80–86
83
tBu
tBu
tBu
tBu
R
R
R
R
R
R
R
R
N
N
N
N
P
P
P
P
P
P
P
P
2 [AuCl(SMe2)]
CH2Cl2
N
N
N
N
Au
Au
tBu
tBu
tBu
tBu
Pt
Pt
Cl
Cl
Cl
Cl
Cl
Cl
5
1d
[R = OC6H4Me-o]
tBu
tBu
tBu
tBu
R
R
R
R
N
N
R
R
R
R
N
N
P
P
P
P
P
P
P
P
2 [AuCl(SMe2)]
CH2Cl2
N
N
Au
Au
N
tBu
tBu
N
Cu
Cu
tBu
tBu
Cl
Cl
I
6
I
1e
Scheme 4. Synthesis of PtII/2AuI and CuI/2AuI complexes.
projecting in an anti-parallel manner so this compound can
serve as an excellent metalloligand for designing hetero
polynuclear complexes. The 1:2 reaction between trans-
[PdCl2{l-L-jP}2] (1c) and [AuCl(SMe2)] in dichlorometh-
ane affords
a
PdII/2AuI hetero-trinuclear complex
[PdCl2{l-L-jP,jP}2(AuCl)2] (4) as shown in Scheme 3.
The 31P NMR spectrum of 4 exhibits two doublets centered
at 105 and 70.5 ppm, respectively, for Au and Pd coordi-
2
nated centers with a JPP coupling of 40 Hz. Again, the
2JPP coupling is not observed in trans-[PdCl2{l-L-jP}2]
(1c) which exhibited single resonances for coordinated
and uncoordinated P-centers.
Heterotrinuclear complexes [PtCl2{l-L-jP,jP}2(AuCl)2]
(5) and [CuI{l-L-jP,jP}2(AuCl)2] (6) containing PtII/
2AuI and CuI/2AuI metal centers were synthesized from
Fig. 1. ORTEP drawing of compound 2. Thermal ellipsoids are drawn at
the 50% probability level. All hydrogen atoms are omitted for clarity.
Table 1
Crystallographic information for 2, 3 and 4
2
3
4
Formula
C
32H46AuCl3N2O4P2Ru
C28H47AuCl3N2O4P3Pd
978.30
monoclinic
P21/n
10.973(1)
15.218(2)
21.589(3)
90
98.630(2)
90
3564.3(8)
4
1.823
5.010
1928
C44H64Au2Cl4N4O8P4Pd
1543.03
monoclinic
P21/c
10.723(3)
19.685(1)
13.700(1)
90
107.307(1)
90
2760.8(3)
2
Formula weight
Crystal system
Space group
989.03
monoclinic
P21/c
13.453(1)
13.589(1)
20.634(2)
90
97.982(1)
90
3735.7(6)
4
˚
a (A)
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
3
˚
V (A )
Z
qcalc (g cmÀ3
)
1.759
4.664
1952
1.856
5.984
1504
l (Mo Ka) (mmÀ1
F(000)
)
Crystal size (mm)
T (K)
0.12 · 0.18 · 0.23
100
0.15 · 0.17 · 0.26
100
0.16 · 0.19 · 0.25
100
2h range (ꢁ)
Total number of reflections
2.1–28.4
23530
2.2–28.3
23926
2.2–28.3
48400
Number of independent reflections [Rint
]
9361 [0.074]
0.0351
0.0776
0.95
8888 [0.042]
0.0341
0.0845
6846 [0.032]
0.0252
0.0681
R1a
wRb2
Goodness-of-fit (F2)
1.01
1.07
P
P
a
R = iFo| À |Fci/ |Fo|.
P
P
b
2
wR2 = {[ w(Fo À Fc2)/ w(Fo2)2]}1/2; w = 1/[r2(Fo2) + (xP)2] where P = (Fo2 + 2Fc2)/3.

84
P. Chandrasekaran et al. / Polyhedron 27 (2008) 80–86
the reaction of cis-[PtCl2{l-L-jP}2] (1d) and [CuI{l-L-
jP}2] (1e) with 2 equiv. of [AuCl(SMe2)] in dichlorometh-
ane at room temperature (Scheme 4). The 31P NMR
spectrum of 5 exhibits a doublet centered at 109.4 ppm
2
for the gold coordinated center with a JPP coupling of
3
36 Hz along with a JPtP coupling of 81 Hz. The platinum
bound phosphorus center exhibits a doublet at 47.0 ppm
along with very large 1JPtP coupling of 5738 Hz, which con-
firms the cis arrangement of the two cyclodiphosphazanes
[15]. The 31P NMR spectrum of complex 6 exhibits two
singlets at 120.9 and 105.9 ppm, respectively, for copper
and gold coordinated phosphorus centers of the cyclo-
diphosphazane.
Fig. 2. ORTEP drawing of compound 3. Thermal ellipsoids are drawn at
the 50% probability level. All hydrogen atoms are omitted for clarity.
3.2. Molecular structures of 2, 3 and 4
The molecular structure of complex 2 is shown in
Fig. 1. Crystal data and details of the structure determina-
tion are presented in Table 1 while selected bond param-
eters are listed in Table 2. The X-ray quality crystals of 2
were obtained by slow diffusion of Et2O into a dichloro-
methane solution of 2 at room temperature. In molecule
2, the cyclodiphosphazane bridges {AuCl} and
{RuCl2(g6-cymene)} fragments through P-coordination
with the metals arranged in a cis orientation. The gold
center is dicoordinated with a P2–Au–Cl3 angle of
176.51(2)ꢁ. The coordination geometry around the ruthe-
nium center in 2 is the typical pseudo octahedral mode
with a three-legged piano-stool arrangement commonly
observed for half-sandwich phosphine complexes [16].
The Ru–P1 and Au–P2 bond distances are 2.348(1) and
and 4 suitable for X-ray diffraction studies were obtained
by slow evaporation of dichloromethane from CH3CN/
CH2Cl2 solutions of the respective compounds at room
temperature. In complexes 3 and 4 the cyclodiphosphazane
ligand cis-{tBuNP(OC6H4OMe-o)}2 (L) bridges the gold
and palladium centers to furnish PdII/AuI, PdII/2AuI het-
erometallic complexes. The palladium atoms occupy the
center of square planar ligand set with the corners occupied
by two chlorides and two phosphorus atoms. As complex 4
has crystallographically-imposed centrosymmetry, the P1–
Pd–P1i and Cl1–Pd–Cl1i bond angles in 4 are exactly linear
and similar to the parent compound 1c [4b]. The gold cen-
ters are linear in geometry with P–Au–Cl angles of
176.25(4)ꢁ and 179.27(3)ꢁ, respectively, for 3 and 4. The
Pd–P bond lengths in 3 and 4 are, respectively the same
and slightly shorter than the corresponding bonds in the
respective mononuclear complexes 1b and 1c [4b]. The exo-
cyclic phenyl substituents on the phosphorus atoms are
present in exo,endo orientations with respect to the planar
P2N2 ring.
˚
2.205(1) A, respectively, and agree well with reported val-
ues for similar complexes of the type [Cp(PPh3)RuCl-
{l-PPh2(CH2)nPPh2}AuCl] [17].
Perspective views of the molecular structures of 3 and 4
are depicted in Figs. 2 and 3, respectively, with important
bond parameters listed in Table 3. Single crystals of 3
Table 2
˚
Selected bond distances (A) and bond angles (ꢁ) for 2
˚
Bond distances (A)
Bond angles (ꢁ)
Ru–P1
Ru–Cl1
Ru–Cl2
Ru–C23
Ru–C24
Ru–C25
Ru–C26
Ru–C27
Ru–C28
Au–P2
Au–Cl3
P1–N1
P1–N2
P2–N1
P2–N2
P1–O1
2.348(1)
2.406(1)
2.391(1)
2.236(3)
2.207(3)
2.211(3)
2.249(3)
2.236(3)
2.221(3)
2.205(1)
2.281(1)
1.706(2)
1.709(2)
1.672(2)
1.670(2)
1.616(2)
1.608(2)
P1–Ru–Cl1
P1–Ru–Cl2
C25–Ru–P1
P2–Au–Cl3
C24–Ru–P1
C25–Ru–P1
C28–Ru–P1
C25–Ru–Cl2
C28–Ru–Cl2
P1–N1–P2
P1–N2–P2
N1–P1–N2
N1–P2–N2
C1–N1–P1
C1–N1–P2
C9–O1–P1
C16–O3–P2
96.51(2)
84.87(2)
94.34(7)
176.51(2)
93.83(7)
94.34(7)
156.07(7)
116.06(7)
118.94(7)
96.77(11)
96.70(11)
81.96(11)
84.12(11)
134.85(18)
127.65(18)
128.52(15)
128.38(18)
Fig. 3. ORTEP drawing of compound 4. Thermal ellipsoids are drawn at
the 50% probability level. All hydrogen atoms are omitted for clarity.
P2–O3

P. Chandrasekaran et al. / Polyhedron 27 (2008) 80–86
85
Table 3
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We are grateful to the Department of Science and Tech-
nology (DST), New Delhi for funding through Grant SR/
S1/IC-02/2007. P.C. thanks CSIR for Research Fellow-
ship. J.T.M. thanks the Louisiana Board of Regents
through Grant LEQSF(2002-03)-ENH-TR-67 for purchase
of the Bruker APEX CCD diffractometer and the Chemis-
try Department of Tulane University for support of the X-
ray laboratory.
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