Stoichiometric reactions of methylparathion with a palladium aryl oxime metallacycle

Article abstract of DOI:10.1039/b411313f

The reaction of [Pd₃(OAc)₆] with (E)-acetophenone oxime and pyridine in CHCl₃ under reflux affords the metallacycle [Pd(OAc){C,N-(C₆H₄C(CH₃)=NOH)-2}(py)] (1) as a yellow air-stable complex. The same reaction carried out at room temperature in the absence of pyridine affords the trinuclear oximato complex [Pd(μ-(E)-ON=C(CH₃)Ph)(μ-OAc)]₃ (2), which can be converted into 1 upon heating in the presence of pyridine. As indicated by ¹H and ³¹P NMR spectroscopy, complex 1 reacts with methylparathion in acetone-d₆-D₂O solutions to afford [Pd(5P(=O)(OCH₃)₂){C,N-(C₆H ₄C(CH₃)=NOH)-2}(py)] (3) and [Pd(μ-SP(=O)(OCH ₃)₂){C,N(C₆H₄C(CH ₃)=NOH)-2}]₂ (4) as well as free p-nitrophenol. Compounds 1-4 have been characterized by single-crystal X-ray analysis, NMR and EA. Compounds 1 and 3 are mononuclear complexes with the acetate and dimethylthiophosphate ligand, respectively, trans from the phenyl group. Compound 2 is a trinuclear complex whose structure can be derived from that of [Pd₃(OAc)₆] by replacing three of the acetate ligands on one side of Pd₃ plane by three N,O-coordinated oximate ligands. Complex 4 is a dinuclear complex in which the two square-planar palladium moieties are linked by the sulfur atoms of the bridging dimethylthiophosphate ligands.

Full text of DOI:10.1039/b411313f

View Article Online / Journal Homepage / Table of Contents for this issue
F U L L P A P E R
Stoichiometric reactions of methylparathion with a palladium aryl
oxime metallacycle
Mieock Kim and François P. Gabbaï*
Chemistry Department, Texas A&M University, 3255 TAMU, College Station,
TX 77843-3255, USA
Received 27th July 2004, Accepted 3rd September 2004
First published as an Advance Article on the web 21st September 2004
The reaction of [Pd3(OAc)6] with (E)-acetophenone oxime and pyridine in CHCl3 under reflux affords the
metallacycle [Pd(OAc){C,N-(C6H4C(CH3)NOH)-2}(py)] (1) as a yellow air-stable complex. The same reaction
carried out at room temperature in the absence of pyridine affords the trinuclear oximato complex [Pd(l-(E)-
ONC(CH3)Ph)(l-OAc)]3 (2), which can be converted into 1 upon heating in the presence of pyridine. As
indicated by 1H and 31P NMR spectroscopy, complex 1 reacts with methylparathion in acetone-d6–D2O solutions
to afford [Pd(SP(O)(OCH3)2){C,N-(C6H4C(CH3)NOH)-2}(py)] (3) and [Pd(l-SP(O)(OCH3)2){C,N-
(C6H4C(CH3)NOH)-2}]2 (4) as well as free p-nitrophenol. Compounds 1–4 have been characterized by single-
crystal X-ray analysis, NMR and EA. Compounds 1 and 3 are mononuclear complexes with the acetate and
dimethylthiophosphate ligand, respectively, trans from the phenyl group. Compound 2 is a trinuclear complex
whose structure can be derived from that of [Pd3(OAc)6] by replacing three of the acetate ligands on one side of Pd3
plane by three N,O-coordinated oximate ligands. Complex 4 is a dinuclear complex in which the two square-planar
palladium moieties are linked by the sulfur atoms of the bridging dimethylthiophosphate ligands.
the stoichiometric reactions that occur between cyclometal-
Introduction
lated palladium aryl oxime complexes and methylparathion
(O,O-dimethyl O-p-nitrophenyl thiophosphate). In this paper,
we report the synthesis of the palladium aryl oxime derivative
[Pd(OAc){C,N-(C6H4C(CH3)NOH)-2}(py)] (1) and the prod-
ucts of its stoichiometric reaction with methylparathion.
Organophosphorus esters that act as acetylcholine esterase
inhibitors are used as pesticides and chemical warfare agents.1
Owing to the obvious adverse natures of these chemicals,2,3
a
great deal of effort has been devoted to the development of
methods that allow for their neutralization.4 In this regard,
hydrolysis reactions that produce non-toxic phosphate or
phosphonate anions have received an increasing amount of
attention. In the case of parathion (O,O-diethyl O-p-nitrophenyl
thiophosphate), a pesticide whose environmental presence is
generating growing concerns,5 the hydrolysis reaction results in
the release of p-nitrophenol and formation of the correspond-
ing thiophosphate diester which is non-toxic. This hydrolysis is
remarkably slow and takes up to several months at neutral pH.6
In the presence of Lewis-acidic transition metal catalysts, the
rate of this reaction increases. While coordination complexes
typically display a marginal activity,7–10 recent reports suggest
that organometallic catalysts can be remarkably active.11,12 In
particular, the group of Ryabov has investigated several cyclo-
metallated palladium and platinum aryl oxime complexes
([MCl{C,N-(C6H4C(CH3)NOH)-2}(L)], M = Pd or Pt, L =
DMSO or pyridine) that greatly accelerate the hydrolysis of
parathion.12 Although no reaction intermediates have been
isolated, it has been proposed that the activity of such catalysts
results from the coordination of parathion at the metal cen-
ter followed by an intramolecular nucleophilic attack by the
neighboring oximate (Scheme 1). Regeneration of the cata-
lysts is proposed to occur by hydrolysis of the phosphorylated
oximate. As part of our general interest in the metal-mediated
hydrolysis of organophosphorus esters, we have decided to visit
Results and discussion
The palladium aryl oxime metallacycle [Pd(OAc){C,N-
(C6H4C(CH3)NOH)-2}(py)] (1) is obtained in one step by
reaction of [Pd3(OAc)6] with (E)-acetophenone oxime and
pyridine in CHCl3 under reflux for 3 h (Scheme 2). Compound
1 is a yellow air-stable complex which can be recrystallized from
benzene. It has been characterized by NMR, elemental analysis
and X-ray analysis (Fig. 1). As expected for a cyclopalladated
complex, the 1HNMRspectrumof 1showsanupfieldshiftof the
proton resonance of the ortho-palladated ring.13,14 Compound 1
crystallizes in the monoclinic P21/c space group. The palladium
atom displays the expected square planar coordination with
the pyridine and oxime nitrogen atoms positioned trans to one
another. The five-membered palladacycle ring of 1 is slightly
Scheme 1
Scheme 2
T h i s j o u r n a l i s
©
T h e R o y a l S o c i e t y o f C h e m i s t r y 2 0 0 4
D a l t o n T r a n s . , 2 0 0 4 , 3 4 0 3 – 3 4 0 7
3 4 0 3

View Article Online
OAc)]3 (2) which is formed in the reaction of [Pd3(OAc)6]
with (E)-acetophenone oxime in CHCl3 at room temperature
(Scheme 2). This compound can be converted into 1 upon
reflux in CHCl3 in the presence of pyridine. Compound 2 has
been characterized by NMR, elemental analysis and X-ray
analysis (Fig. 2). This derivative crystallizes with two molecule
of interstitial benzene in the asymmetric unit. It features a
trinuclear structure similar to that observed for [Pd3(OAc)6]16
and the related oximate complex [Pd(l-(Z)-ONCiPrPh)2]3.17
The structure of 2 can be derived from that of [Pd3(OAc)6] by
replacement of three of the acetate ligands on one side of Pd3
plane by three N,O-coordinated oximate ligands. The resulting
Pd–N (av. 1.99 Å) and Pd–O (av. 2.00 Å) are similar to those
observed in the structure of [Pd(l-(Z)-ONCiPrPh)2]3.17
Complex 1 promptly reacts with methylparathion in acetone-
d6–D2O solution. While methylparathion is stable for several
weeks in these aqueous solvent mixtures, addition of 1 results
in the rapid production of p-nitrophenol as shown by 1H NMR
spectroscopy (Scheme 3). This reaction is also accompanied by
the appearance of two phosphorus containing products, namely,
[Pd(SP(O)(OCH3)2){C,N-(C6H4C(CH3)NOH)-2}(py)] (3)
and [Pd(l-SP(O)(OCH3)2){C,N-(C6H4C(CH3)NOH)-2}]2
(4) which give rise to 31P NMR signals at 53 and 29 ppm,
respectively. Both of these signals are upfield from the 31P reso-
nance of methylparathion which appears at 66 ppm18 and do
not correspond to the thiosphosphoric acid HSP(O)(OMe)2
derivative whose 31P resonance appears at 65 ppm.19 Upon
longer reaction time, the signal corresponding to methyl-
parathion at 67 ppm ultimately disappears to afford 3 and 4
in a 9:1 ratio. Compounds 3 and 4 simultaneously crystallize
from the reaction mixture which complicated their isolation
in a pure form. Single crystals could however be separated on
the basis of their colors and were characterized by NMR and
X-ray analysis. Complex 3 (Fig. 3) is a mononuclear yellow
complex which crystallizes in the monoclinic space group C2/c.
Its structure can be derived from that of 1 by substitution of
the acetate ligand with a sulfur-bound dimethylthiophosphate
ligand which originates from the hydrolyzed methylparathion.
The resulting Pd–S bond of 2.461(1) Å is similar to that of
the cyclometallated palladium dithiolate complex [Pd{C,N-
N(Me)2CH2C6H4-2}{S,S-S2P(OPrn)2}] (2.458(2) Å).20 The P–S
bond length of 1.982(1) Å is intermediate between double bond
(1.94 Å) and single bond (2.09 Å) values. All other structural
parameters are almost identical to those found in 1. As in 1,
the oxime functionality is protonated and hydrogen bonded
to the phosphoryl oxygen atom O(2) (O(1)O(2) = 2.615 Å).
Complex 4 (Fig. 4) is a dinuclear orange complex which crys-
tallizes in the monoclinic space group P21/c. The two square-
planar palladium moieties are linked by the sulfur atoms of the
bridging dimethylthiophosphate ligands. The Pd–S distances
of 2.327(1) and 2.473 (1) Å are comparable to those observed
in related complexes such as [Pd2((t-BuNH)2P(O)S)4] (av.
Pd–S = 2.34 Å) which also features bridging thiophosphate
groups.21 The Pd–S distance of 2.473(1) Å trans to the carbon
atom of the cyclometallated ligand is slightly longer than that
of 2.327(1) Å trans to the Pd–N bond due to the trans influence
originating from the orthometallated phenyl ligand.10,22 As in 3,
the O(1A)O(2) distance of 2.662 Å indicate that presence of a
hydrogen bond between the protonated oxime functionality and
the phosphoryl oxygen atom. All other structural parameters
are almost identical to those found in 1.
Fig. 1 Structure of complex 1 in the crystal. Selected bond lengths (Å)
and angles (°). Pd(1)–C(1) 1.974(6), Pd(1)–N(1) 2.018(5), Pd(1)–N(2)
2.048(5), Pd(1)–O(3) 2.145(4); C(1)–Pd(1)–N(1) 80.3(2), C(1)–Pd(1)–
N(2) 94.4(2), N(1)–Pd(1)–N(2) 174.7(2), C(1)–Pd(1)–O(3) 175.9(2),
N(1)–Pd(1)–O(3) 103.79(19), N(2)–Pd(1)–O(3) 81.48(18).
Fig. 2 Structure of complex 2 in the crystal. Selected bond lengths (Å)
and angles (°). Pd(1)–O(4) 1.996(8), Pd(1)–N(1) 2.002(10), Pd(1)–O(3)
2.004(8), Pd(1)–O(9) 2.021(8), Pd(1)–Pd(3) 3.0146(15), Pd(1)–Pd(2)
3.0327(15), Pd(2)–Pd(3) 3.0712(17); O(4)–Pd(1)–N(1) 89.3(4), O(4)–
Pd(1)–O(3) 172.0(3), N(1)–Pd(1)–O(3) 90.7(4), O(4)–Pd(1)–O(9) 90.0(3),
N(1)–Pd(1)–O(9) 175.7(4), O(3)–Pd(1)–O(9) 89.4(3), Pd(3)–Pd(1)–Pd(2)
61.04(4), Pd(1)–Pd(2)–Pd(3) 59.19(3), Pd(1)–Pd(3)–Pd(2) 59.77(3).
strained (bond angle of C(1)–Pd–N(1) is 80.3°). The Pd–C(1)
bond length of 1.974(6) Å is typical of Pd–C(sp2) bonds of
compounds featuring a square-planar palladium bound to a co-
planar aryl ring.15 Altogether, this structure is similar to that of
[PdCl{C,N-(C6H4C(CH3)NOH)-2}(py)].14 The acetate ligand
is terminally ligated through one of its oxygen atoms. As indi-
cated by the O(1)–O(2) distance of 2.512 Å, the non-coordinated
carbonyl oxygen atom of the acetate ligand (O(2)) is hydrogen
bonded to the protonated oxime functionality.
In the course of these investigations, we were able to isolate
the trinuclear oximato complex [Pd(l-(E)-ONC(CH3)Ph)(l-
Scheme 3
3 4 0 4
D a l t o n T r a n s . , 2 0 0 4 , 3 4 0 3 – 3 4 0 7

View Article Online
75.4 or 125.7 MHz for 13C, 121.4 MHz for 31P NMR). 85%
H3PO4 was used as an external standard for the solution 31P
NMR spectra. The proton and carbon signals of the deuterated
solvent were used as internal standard for the 1H and 13C NMR
spectra, respectively. Elemental analyses were performed by
Atlantic Microlab Inc. at Norcross, GA 30091. Melting points
were measured on a Laboratory Devices Mel-Temp apparatus
and were not corrected. The methylparathion solution was pro-
vided by A/S CHEMINOVA, LEMVIG, DK-7620, Denmark
as a gift. (E)-Acetophenone oxime was synthesized by the
reaction of acetophenone with hydroxylamine hydrochloride in
EtOH–pyridine as described in the literature.23
[Pd(OAc){C,N-(C6H4C(CH3)NOH)-2}(py)] (1)
Method1.Acetophenoneoxime(0.14ml,1mmol)andpyridine
(0.16 ml, 2 mmol) were added to a solution of palladium acetate
(224 mg, 1 mmol) in CHCl3 (15 ml). The resulting orange–red
solution was refluxed for 3 h. Following addition of water
(10 ml), the product was extracted with chloroform (3 × 15 ml).
Evaporation of the solvents yielded a yellow oil which was dis-
solved in benzene. Slow evaporation of the solvent led to the
formation of bright yellow crystals of 1 (360 mg, 95%); mp
163 °C. Anal. C15H16N2O3Pd requires C 47.57, H 4.26. Found:
C 47.47, H 4.34%. 1H NMR (500 MHz, CDCl3): d 8.79 [2H, d,
J(HH) 7.5 Hz, NC5H5], 7.94 [1H, t, J(HH) 7.5 Hz, NC5H5], 7.47
[2H, t, J(HH) 7.5 Hz, NC5H5], 7.05 [1H, d, J(HH) 7.0 Hz], 7.01
[1H, t, J(HH) 7.0 Hz] and 6.77 [1H, t, J(HH) 7.0 Hz] (H-arom,
H3–H5 of Pd–C6H4C(CH3)NOH), 6.15 [1H, d, J(HH) 7.0 Hz,
H6 of Pd–C6H4C(CH3)NOH], 2.24 [3H, s, CO2CH3], 1.89 [3H,
s, NCH3]. 13C NMR (75.4 MHz, CDCl3): d 180.7 [CO2CH3],
164.7 [Pd–C6H4C(CH3)NOH], 152.9, 151.3, 145.3, 138.8,
132.5, 127.7, 125.7, 125.0, and 124.8 [Pd–C6H4C(CH3)NOH
and NC5H5], 24.6 [CO2CH3], 11.4 [C6H4C(CH3)NOH].
Fig. 3 Structure of complex 3 in the crystal. Selected bond lengths (Å)
and angles (°). Pd(1)–C(1) 1.995(3), Pd(1)–N(1) 2.017(3), Pd(1)–N(2)
2.038(3), Pd(1)–S(1) 2.4609(10), S(1)–P(1) 1.982(1); C(1)–Pd(1)–N(1)
79.88(12), C(1)–Pd(1)–N(2) 93.62(12), N(1)–Pd(1)–N(2) 170.58(11),
C(1)–Pd(1)–S(1) 172.81(9), N(1)–Pd(1)–S(1) 99.54(8), N(2)–Pd(1)–S(1)
87.76(8), P(1)–S(1)–Pd(1) 96.46(5).
Method 2. Pyridine (0.08 ml, 1.0 mmol) was added to a
solution of 2 (270 mg, 0.3 mmol) in CHCl3 (15 ml). The
resulting orange–red solution was refluxed for 3 h. Follow-
ing addition of water (10 ml), the product was extracted with
chloroform (3 × 15 ml). Evaporation of the solvents yielded a
yellow oil which was dissolved in benzene. Slow evaporation of
the solvent led to the formation of bright yellow crystals of 1
(327 mg, 96%).
[Pd(l-(E)–ONC(CH3)Ph)(l-OAc)]3 (2)
A suspension of palladium acetate (224 mg, 1 mmol) in acetic
acid (6 ml) was added to a solution of acetophenone oxime
(0.14 ml, 1 mmol). Stirring the resulting solution overnight at
room temperature resulted in precipitation of orange micro-
crystals of 2 (270 mg, 90%) which were collected by filtration
and washed with H2O and n-hexane. Anal. C30H33N3O9Pd3
Fig. 4 Structure of complex 4 in the crystal. Selected bond lengths (Å)
and angles (°). Pd(1)–C(1) 2.003(4), Pd(1)–N(1) 2.029(3), Pd(1)–S(1)
2.3268(10), Pd(1)–S(1A) 2.4727(10), S(1)–P(1) 2.061(1); C(1)–Pd(1)–
N(1) 79.57(14) C(1)–Pd(1)–S(1) 97.44(11), N(1)–Pd(1)–S(1) 176.53(9),
C(1)–Pd(1)–S(1A) 177.96(11), S(1)–Pd(1)–S(1A) 84.47(4).
1
requires C 40.09, H 3.70. Found: C 40.15, H 3.73%. H NMR
Conclusion
(300 MHz, CDCl3): d 8.09 [2H, d, J(HH) 7.0 Hz, N(CH3)C6H5],
7.60 [2H, t, 2H, J(HH) 7.0 Hz, N(CH3)C6H5], 7.50 [1H, t,
J(HH) 7.0 Hz, N(CH3)C6H5], 2.04 [3H, s, CO2CH3], 2.02 [3H,
s, NC(CH3)C6H5]. 13C NMR (75.4 MHz, CDCl3): d 184.0
[CO2CH3], 158.6 [NC(CH3)C6H5], 137.5, 129.7, 128.6 and
127.3 [NC(CH3)C6H5], 23.2 [CO2CH3], 18.1 [N(CH3)C6H5].
The reaction of the palladium aryl oxime complex 1 with
methylparathion leads to the formation of isolable palladium
thiophosphate compounds. The formation of these com-
pounds reflects the thiophilic character of palladium and
possibly accounts for the ability of such complexes to promote
the hydrolysis of methylparathion. These findings suggest that
thiophosphate complexes such as 3 are possible intermediates in
the catalyzed hydrolysis of methylparathion by cyclometallated
palladium aryl oxime complexes.
Reaction of 1 with methylparathion: formation of [Pd(SP(O)-
(OCH3)2){C,N-(C6H4C(CH3)NOH)-2}(py)] (3) and [Pd(l-
SP(O)(OCH3)2){C,N-(C6H4C(CH3)NOH)-2}]2 (4)
A 80 wt% solution of methylparathion in xylenes (362 mg,
1.1 mmol) was added to a solution of complex 1 (380 mg,
1 mmol) in acetone (10 ml) and water (0.5 mL). After 24 h,
the integrated 31P NMR spectrum of the mixture indicated
complete consumption of methyl parathion and formation of
3 and 4 in a 9:1 ratio. Evaporation of the volatiles afforded an
oily residue which was dissolved in CHCl3 (40 mL), washed with
Experimental
General considerations
CAUTION: Methylparathion is highly toxic and should be
handled in a well-ventilated fume hood. Solvents were dried by
standard method. All NMR studies were carried out on Inova
1
300 or 500 MHz NMR spectrometer (300 or 500 MHz for H,
D a l t o n T r a n s . , 2 0 0 4 , 3 4 0 3 – 3 4 0 7
3 4 0 5

View Article Online
Table 1 Crystal data, data collection, and structure refinement for complexes 1–4
Crystal data
1
2·2C6H6
3
4
Formula
Mr
Crystal size/mm
Crystal system
C15H16N2O3Pd
378.70
0.45 × 0.20 × 0.20
Monoclinic
P21/c
C42H45N3O9Pd3
1055.01
0.18 × 0.06 × 0.06
Monoclinic
P21/c
C15H19N2O4PPdS
460.75
0.86 × 0.27 × 0.06
Monoclinic
C2/c
C10H14NO4PPdS
381.65
0.25 × 0.17 × 0.14
Monoclinic
P21/c
Space group
a/Å
b/Å
c/Å
11.848(3)
17.343(4)
7.1257(16)
99.488(4)
1444.2(6)
4
1.742
1.296
760
10.207(3)
16.621(5)
24.231(7)
94.142(5)
4100(2)
13.240(4)
15.252(5)
17.807(6)
94.532(8)
3585(2)
7.6851(12)
18.574(3)
9.4072(16)
101.870(3)
1314.1(4)
4
1.929
1.697
760
b/°
V/Å3
Z
4
8
Dc/g cm−3
l(Mo-Ka)/mm−1
F(000)/e
1.709
1.360
2112
1.707
1.262
1856
Data collection
T/K
Scan mode
hkl range
110(2)
x
−13 to 13, −19 to 19,
−8 to 8
9772
110(2)
x
−11 to 11, −18 to 18,
−17 to 26
20737
110(2)
x
−14 to 8, −15 to 16,
−19 to 10
3150
110(2)
x
−4 to 8, −20 to 10,
−9 to 10
3696
Measured refl.
Unique refl. [Rint]
Refl. used for refinement
Absorption correction
Tmin/Tmax
2271 [0.0367]
2271
Empirical
0.8344/0.6768
5903 [0.0957]
5903
Empirical
0.7931/0.6922
2133 [0.0247]
2133
None
1709 [0.0340]
1709
None
Refinement
Refined parameters
R1,a wR2b [I > 2r(I)]
qmax/min/e Å−3
190
478
217
167
0.0468, 0.1032
2.147/−0.884
0.0645, 0.1288
1.781/−0.636
0.0237, 0.0657
0.362/−0.319
0.0248, 0.0629
0.545 and −0.648
2
2
a R1 = (Fo − Fc)/Fo. b wR2 = {[w(Fo2 − Fc2)2]/[w(Fo )2]}1/2; w = 1/[r2(Fo ) + (ap)2 + bp]; p = (Fo2 + 2Fc2)/3; a = 0.055 (1), 0.03 (2), 0.04 (3), 0.0361 (4); b =
15 (1), 0 (2), 4 (3), 0.9441 (4).
H2O and concentrated to 5 mL. Small yellow crystals of 3 and
orange crystals of 4 coated by a dark oily residue formed upon
standing. Compounds 3 and 4 were obtained as a mixture such
that a satisfactory elemental analysis could not be obtained.
References
1 Pesticides remediation in soils and water, ed. P. C. Keaney and
T. Roberts, Wiley, New York, 1998.
2 H. A. Alegria and T. J. Shaw, Environ. Sci. Technol., 1999, 33,
850–856.
3 R. J. Gilliom, J. E. Barbash, D. W. Kolpin and S. J. Larson, Environ.
Sci. Technol. A, Pages, 1999, 33, 164A–169A.
4 (a) H. Morales-Rojas and R. A. Moss, Chem. Rev., 2002, 102,
2497–2521; (b) Y. C. Yang, J. A. Baker and J. R. Ward, Chem. Rev.,
1992, 92, 1729–1743.
5 R. Reichman, Y. Mahrer and R. Wallach, Environ. Sci. Technol.,
2000, 34, 1321–1330.
6 S. B. Lartiges and P. P. Garrigues, Environ. Sci. Technol., 1995, 29,
1246–1254.
7 J. A. A. Ketellaar, H. R. Gersmann and M. Beck, Nature, 1956, 177,
392–393.
8 (a) M. Zeinali and A. Torrents, Environ. Sci. Technol., 1998, 32,
2338–2342; (b) J. M. Smolen and A. T. Stone, Environ. Sci. Technol.,
1997, 31, 1664–1673; (c) H. B. Wan, M. K. Wong and C. Y. Mok,
Pestic. Sci., 1994, 42, 93–99.
1
3. H NMR (300 MHz, acetone-d6): d 8.89 [2H, d, J(HH)
7.2 Hz, NC5H5], 7.70 [2H, t, J(HH) 7.2 Hz, NC5H5], 7.24 [1H,
d, J(HH) 7.2 Hz, NC5H5], 6.7–7.1 [3H, m, H-arom, H3–H5
of Pd–C6H4C(CH3)NOH], 5.93 [2H, d, J(HH) 7.2 Hz, H6
of Pd–C6H4C(CH3)NOH], 3.61 [6H, d, J(HP) 12.6 Hz,
CH3OP], 2.29 [3H, s, Pd–C6H4C(CH3)NOH]. 13C NMR
(75.4 MHz, CDCl3): d 162.5 [Pd–C6H4C(CH3)NOH], 153.0,
152.5, 143.7, 138.1, 130.5, 128.5, 125.2, 124.3 and 123.6 [Pd–
C6H4C(CH3)NOH and NC5H5], 54.4 [d, J(HP) 2.6, P–OCH3)
10.6 [s, Pd–C6H4C(CH3)NOH)]. 31P NMR (121.4 MHz,
acetone-d6): d 53.6 [s].
1
4. H NMR (500 MHz, CDCl3): d 7.0–7.4 [8H, m, H-arom
9 (a) C. M. Hartshorn, A. Singh and E. L. Chang, J. Mater.
Chem., 2002, 12, 602–605; (b) R. A. Moss and H. Morales-
Rojas, Langmuir, 2000, 16, 6485–6491; (c) F. M. Menger,
L. H. Gan, E. Johnson and D. H. Durst, J. Am. Chem. Soc.,
1987, 109, 2800–2803; (d) J. R. Morrow and W. C. Trogler, Inorg.
Chem., 1989, 28, 2330–2333; (e) R. A. Moss, P. K. Gong and
H. Morales-Rojas, Org. Lett., 2002, 4, 1835–1838; (f) R. W. Hay,
T. Clifford, D. T. Richens and P. Lightfoot, Polyhedron, 2000, 19,
1485–1492.
Pd–C6H4C(CH3)NOH], 4.00 (12H, d, J(HP) 12.5 Hz, CH3OP),
2.30 [s, 3H, Pd–C6H4C(CH3)NOH]. 31P NMR (121.4 MHz,
acetone-d6): d 29.3 [s]. A satisfactory 13C spectrum could not be
obtained because of insufficient sample.
Crystallography
Crystal data, data collection, and structure refinement for
complexes 1–4 are provided in Table 1.
CCDC reference numbers 245836–245839.
See http://www.rsc.org/suppdata/dt/b4/b411313f/ for crystal-
lographic data in CIF or other electronic format.
10 P. Hendry and A. M. Sargeson, Aust. J. Chem., 1986, 39, 1177–
1186.
11 L. Y. Kuo and N. M. Perera, Inorg. Chem., 2000, 39, 2103–
2106.
12 G. M. Kazankov, V. S. Sergeeva, E. N. Efremenko, L. Alexandrova,
S. D. Varfolomeev and A. D. Ryabov, Angew. Chem., Int. Ed., 2000,
39, 3117–3119.
13 H. Onoue, K. Minami and K. Nakagawa, Bull. Chem. Soc. Jpn.,
1970, 43, 3480–3485.
14 A. D. Raybov, G. M. Kazankov, A. K. Yatsimirsky, L. G. Kuz’mina,
O. Y. Burtseva, N. V. Dvortsova and V. A. Polyako, Inorg. Chem.,
1992, 31, 3083–3090.
Acknowledgements
Support from the US Army Medical Research and Material
Command as well as the Korea Science and Engineering Foun-
dation (Grant to M. K.) is gratefully acknowledged. We thank
A/S CHEMINOVA for providing us with methylparathion.
3 4 0 6
D a l t o n T r a n s . , 2 0 0 4 , 3 4 0 3 – 3 4 0 7

View Article Online
15 Yu. Struchkov, A. S. Batsanov and Yu. L. Slovokhotov, Sov. Sci.
Rev. B.: Chem., 1987, 10, 386.
16 A. C. Skapski and M. L. Smart, J. Chem. Soc. D., 1970, 658.
17 A. G. Constable, W. S. McDonald, L. C. Sawkins and B. L. Shaw,
Chem. Commun., 1978, 1061–1062.
20 S. Narayan, V. K. Jain and R. J. Butcher, J. Organomet. Chem., 1997,
549, 73–80.
21 O. J. Scherer, K. Forstinger, J. Kaub and W. S. Sheldrick, Chem. Ber.,
1986, 119, 2731–2747.
22 Y. Qin, S. Selvaratnam, J. J. Vittal and P.-H. Leung, Organometallics,
2002, 21, 5301–5306.
23 (a) M. A. Bigdeli, Mir. M. A. Nikje, S. Jafari and M. M. Heravi, J.
Chem. Res. (S), 2002, 20–21; (b) J.-M. Coustard, J.-C. Jacquesy and
B. Violeau, Tetrahedron Lett., 1992, 33, 8085–8086; (c) B. S. Furniss,
A. J. Hannaford, P. W. G. Smith and A. R. Tatchell, Vogel’s textbook
of practical organic chemistry, Longmans, London, 5th edn., 1996,
p. 1259.
18 T. Kuivalainen, J. El-Bahrauoui, R. Uggla, R. Kostiainer and M. R.
Sundberg, J. Am. Chem. Soc., 2000, 122, 8073–8074.
19 (a) The chemical 31P shift of dimethylthiophosphate salt has
been previously reported: M. Mahajna, G. B. Quistad and J. E.
Casida, Chem. Res. Toxicol., 1997, 10, 64–69; (b) P. C. J. Jamer,
H. C. P. F. Roelen, H. van den Elst, G. A. van der Marel and
J. H. van Boom, Tetrahedron Lett., 1989, 30, 6757–6760.
D a l t o n T r a n s . , 2 0 0 4 , 3 4 0 3 – 3 4 0 7
3 4 0 7