Unusual Reactivity Mode of Coordinated Oximes: Platinum(IV)-Assisted Ring Closure by Reaction with Acetone

Article abstract of DOI:10.1021/ic950351s

The platinum(II) complexes trans-[PtCl₂(RR'C=NOH)₂], where R = R' = Me, RR' = (CH₂)₄ and (CH₂)₅, react with m-chloroperoxybenzoic acid in Me₂CO to give the platinum(IV) complexes [PtCl₂(OCMe₂ON=CRR')₂] in 50-60% yields. The complexes [PtCl₂(OCMe₂ON=CRR')₂] were characterized by elemental analysis, EI-MS, and IR and Raman spectroscopies; X-ray structure analyses were performed for both irons-[PtCl₂(OCMe₂-ON=CC₄H₈) ₂] and trans-[PtCl₂(OCMe₂ON==CC₅H₁₀) ₂]- The former compound crystallizes in the triclinic space group P1? with a = 8.088(2) ?, b = 8.327(2) ?, c = 8.475(2) ?, α = 103.54(3)°, β= 102.15(3)°, γ = 108.37(3)°, V = 501.0(2) ?³, Z = 1, and p_calcd = 1.917 g cm^-3. The latter complex crystallizes in the monoclinic space group C2/c with a = 12.5260(10) ?, b = 9.3360(10) ?, c = 18.699(2) ?, β= 98.320(10)°, V = 2163.7(4) ?³, Z = 4, and ρ_calcd; = 1.862 g cm^-3. The structures of [PtCl₂(COMe₂ON=CC₄H₈)₂] and [PtCl₂(OCMe₂ON=CC₅H₁₀)₂] show an octahedron of Pt where two Cl atoms and two chelate ligands are mutually trans, respectively.

Full text of DOI:10.1021/ic950351s

510
Inorg. Chem. 1996, 35, 510-513
Unusual Reactivity Mode of Coordinated Oximes: Platinum(IV)-Assisted Ring Closure by
Reaction with Acetone
Vadim Yu. Kukushkin,*,1a Vitaly K. Belsky,1b and David Tudela*,1c
Department of Chemistry, St. Petersburg State University, 198904 Stary Petergof, Russian Federation,
L. Ya. Karpov Physico-Chemical Institute, Obukha Str. 10, 103064 Moscow, Russian Federation, and
Departamento de Qu´ımica Inorga´nica, Universidad Auto´noma de Madrid, 28049 Madrid, Spain
ReceiVed March 23, 1995X
The platinum(II) complexes trans-[PtCl2(RR′CdNOH)2], where R ) R′ ) Me, RR′ ) (CH2)4 and (CH2)5, react
with m-chloroperoxybenzoic acid in Me2CO to give the platinum(IV) complexes [PtCl2(OCMe2ONdCRR′)2] in
50-60% yields. The complexes [PtCl2(OCMe2ONdCRR′)2] were characterized by elemental analysis, EI-MS,
and IR and Raman spectroscopies; X-ray structure analyses were performed for both trans-[PtCl2(OCMe2-
ONdCC4H8)2] and trans-[PtCl2(OCMe2ONdCC5H10)2]. The former compound crystallizes in the triclinic space
group P1h with a ) 8.088(2) Å, b ) 8.327(2) Å, c ) 8.475(2) Å, R ) 103.54(3)°, â ) 102.15(3)°, γ ) 108.37(3)°,
V ) 501.0(2) Å3, Z ) 1, and Fcalcd ) 1.917 g cm-3. The latter complex crystallizes in the monoclinic space
group C2/c with a ) 12.5260(10) Å, b ) 9.3360(10) Å, c ) 18.699(2) Å, â ) 98.320(10)°, V ) 2163.7(4) Å3,
Z ) 4, and Fcalcd ) 1.862 g cm-3. The structures of [PtCl2(OCMe2ONdCC4H8)2] and [PtCl2(OCMe2ONdCC5H10)2]
show an octahedron of Pt where two Cl atoms and two chelate ligands are mutually trans, respectively.
Introduction
supported stabilization of PtIII-PtIII derivatives,12 and dehydra-
tion with formation of metal-bonded organonitriles13,14 or
azavynilidene-type complexes.14,15 In high-oxidation-state metal
ion complexes, hydrolysis followed by oxidation is ob-
served.16
The coordination chemistry and reactivity of complexes
containing so-called “simple” oximes, e.g. ligands which have
merely one oxime group as the only coordination site,2 is a
relatively unexplored area. Nevertheless, nonsystematic and
scattered works from different groups show that oxime-
containing complexes display very interesting reactivity modes.
Reported examples include deprotonation either preserving the
Pt-N bond3 or leading to formation of Pt-O-N oximato and
bridging oximato µ2-η2-ONCR2 complexes,4 the Beckmann
rearrangement,5 deoxygenation,6 metal-ion assisted addition of
oximes to nitriles,7,8 cleavage of the CdN bond,9 oxidative
addition,10 ortho-palladation of aromatic oximes,11 oxime-ligand-
Recently, we have demonstrated that the oxidation of cis-
[PtCl2(RR′CdNOH)2], where R ) R′ ) Me, RR′ ) (CH2)4
and (CH2)5, by molecular chlorine yields cis-[PtCl4-
(RR′CdNOH)2].17 The latter compounds, on standing in
water-acetone solution, undergo an unusual spontaneous
Pt(IV)-mediated redox coupling leading to the platinum(II)
chelate [PtCl2(N(dO)CRR′ONCRR′)], shown in Scheme 1. We
have no indication of participation of acetone as a reagent in
this reaction.
X Abstract published in AdVance ACS Abstracts, December 15, 1995.
(1) (a) St. Petersburg State University; Internet: prof@inorg.spb.su. (b)
L. Ya. Karpov Physico-Chemical Institute; Internet: belsky@
nifhi4.rc.ac.ru. (c) Universidad Auto´noma de Madrid; Fax: +34-1-
397 4833, Internet: DATUDELA@ccuam3.sdi.uam.es.
(2) Mehrotra, R. C. In ComprehensiVe Coordination Chemistry; Wilkin-
son, G., Gillard, R. D., McCleverty J. A., Eds.; Pergamon Press:
Oxford, 1987; Vol. 2, pp 269-270.
(3) (a) Grinberg, A. A.; Stetsenko, A. I.; Strelin, S. G. Zh. Neorg. Khim.
1968, 13, 1089. (b) Stetsenko, A. I.; Strelin, S. G.; Gelfman, M. I.
Zh. Neorg. Khim. 1970, 15, 134. (c) Stetsenko, A. I.; Skvortsov, N.
K.; Lipner, B. S. Zh. Obshch. Khim. 1975, 45, 1783. (d) Kukushkin,
Yu. N.; Stetsenko, A. I.; Duibanova, V. G.; Strelin, S. G. Zh. Neorg.
Khim. 1974, 19, 2497. (e) Kukushkin, Yu. N.; Stetsenko, A. I.;
Duibanova, V. G.; Strelin, S. G. Zh. Neorg. Khim. 1971, 16, 3078. (f)
Stetsenko, A. I.; Lipner, B. S. Zh. Obshch. Khim. 1974, 44, 2289. (g)
Kukushkin, Yu. N.; Stetsenko, A. I.; Strelin, S. G.; Duibanova, V. G.
Zh. Neorg. Khim. 1972, 17, 1083.
(8) Caglioti, L.; Galli, B.; Gasparrini, F.; Natile, G. In Proceedings of
Congresso Interdivisionale Della Societa Chimica Italiana; San Bene-
detto del Tronto, 30 Sept-5 Oct, 1990; p 521.
(9) (a) Kumar, H.; Kaur, B.; Kumar, B. Indian J. Chem., Sect. B 1991,
30B, 869. (b) Rao, K. N.; Sethuram, B.; Rao, T. N. Oxid. Commun.
1987, 95.
(10) Deeming, A. J.; Owen, D. W.; Powell, N. J. J. Organomet. Chem.
1990, 398, 299.
(11) Ryabov, A. D.; Kazankov, G. M.; Yatsimirsky, A. K.; Kuz’mina, L.
G.; Burtseva, O. Yu.; Dvortsova, N. V.; Polyakov, V. A. Inorg. Chem.
1992, 31, 3083.
(12) Baxter, L. A. M.; Heath, G. A.; Raptis, R. G.; Willis, A. C. J. Am.
Chem. Soc. 1992, 114, 6944.
(13) (a) Kaneda, K.; Doken, K.; Imanaka, T. Chem. Lett. 1988, 285. (b)
Kaneda, K.; Fujita, K.; Takemoto, T.; Imanaka, T. Bull. Chem. Soc.
Jpn. 1991, 64, 602. (c) Olczak-Kobza, M. Thermochim. Acta 1988,
A133, 347.
(4) (a) Babaeva, A. B.; Mosyagina, M. A. Dokl. Akad. Nauk SSSR 1953,
89, 293. (b) Beirakhov, A. G.; Orlova, I. M.; Ashurov, Z. P.; Lobanova,
G. M.; Mikhailov, Yu. N.; Schelokov, R. N. Zh. Neorg. Khim. 1990,
35, 3139. (c) Meyer, U.; Werner, H. Chem. Ber. 1990, 123, 697. (d)
Langenbahn, M.; Stoeckli-Evans, H.; Su¨ss-Fink, G. J. Organomet.
Chem. 1990, 397, 347.
(5) Bolshakov, A. M.; Ershova, M. M.; Glushkova, M. A.; Buslaev, Yu.
A. Koord. Khim. 1978, 4, 1767.
(6) (a) Charalambous, J.; Haines, L. I. B.; Morgan, J. S.; Peat, D. S.;
Campbell, M. J. M.; Bailey, J. Polyhedron 1987, 6, 1027. (b)
Langenbahn, M.; Stoeckli-Evans, H.; Su¨ss-Fink, G. HelV. Chim. Acta
1991, 74, 549.
(14) Daniel, T.; Knaup, W.; Dziallas, M.; Werner, H. Chem. Ber. 1993,
126, 1981.
(15) (a) Werner, H.; Knaup, W.; Dziallas, M. Angew. Chem. 1987, 99,
277. (b) Werner, H.; Daniel, T.; Knaup, W.; Nu¨rnberg, O. J.
Organomet. Chem. 1993, 462, 309.
(16) (a) Bleaupre, P. W.; Holland, W. J. Mikrochim. Acta 1983, 3, 341.
(b) Tananaev, I. G.; Shilov, V. P.; Krot, N. N. Radiokhimiya 1986,
28, 92. (c) Shilov, V. P.; Krot, N. N.; Stepanova, E. S. Radiokhimiya
1976, 18, 355.
(17) (a) Kukushkin, V. Yu.; Belsky, V. K.; Aleksandrova, E. A.;
Konovalov, V. E.; Kirakosyan, G. A. Inorg. Chem. 1992, 31, 3836.
(b) Kukushkin, V. Yu.; Belsky, V. K.; Konovalov, V. E.; Aleksan-
drova, E. A.; Pankova, E. Yu. Zh. Obshch. Khim. 1991, 61, 254. (c)
Kukushkin, V. Yu. Unpublished results.
(7) Grigg, J.; Collison, D.; Garner, C. D.; Helliwell, M.; Tasker, P. A.;
Thorpe; J. M. J. Chem. Soc., Chem. Commun. 1993, 1807.
0020-1669/96/1335-0510$12.00/0 © 1996 American Chemical Society

Unusual Reactivity Mode of Coordinated Oximes
Inorganic Chemistry, Vol. 35, No. 2, 1996 511
Table 1. Crystal Data and Structure Refinement for
Scheme 1
[PtCl2(OCMe2ONdCC4H8)2] and [PtCl2(OCMe2ONdCC5H10)2]
empirical formula
fw
C16H28Cl2N2O4Pt
578.39
C18H32Cl2N2O4Pt
606.45
crystal system
space group
a, Å
b, Å
c, Å
triclinic
monoclinic
C2/c (No. 15)
12.5260(10)
9.3360(10)
18.699(2)
90
98.320(10)
90
2163.7(4)
4
P1h (No. 2)
8.088(2)
8.327(2)
8.475(2)
103.54(3)
102.15(3)
108.37(3)
501.0(2)
1
As an extension of this study, we have found that trans-
[PtCl2(RR′CdNOH)2] displays intriguing reactivity toward
oxidation in acetone. We report herein the oxidation of trans-
[PtCl2(RR′CdNOH)2] by m-chloroperoxybenzoic acid (MCP-
BA) in Me2CO, where acetone acts as both the solvent and
reagent.
R, deg
â, deg
γ, deg
V, Å3
Z
F(calcd), g cm-3
T, K
1.917
293(2)
1.862
293(2)
radiation, λ (Å)
Mo KR, Nb-filter,
0.710 73
7.290
2.60-24.97
1927
1759
0.012/0.030
Mo KR, Nb-filter,
0.710 73
6.757
2.20-24.95
1448
975
0.012/0.032
Experimental Section
µ, mm-1
θ range, deg
no. of coll reflcns
no. of reflcns for calc
R1a/wR2b
Materials and Instrumentation. The oxime ligands and K2[PtCl4]
were purchased from Aldrich and Reakhim, respectively, and used as
received. MCPBA was purchased from Aldrich (57-86%; contains
7-10% 3-chlorobenzoic acid, the remainder being water) and was not
titrated. trans-[PtCl2(RR′CdNOH)2] (RR′d(CH2)4 and (CH2)5) were
prepared by heating the appropriate cis-isomers in the solid phase at
135 and 140 °C, respectively.18 trans-[PtCl2(Me2CdNOH)2] was
synthesized by the published method17a from K2[PtCl4] and excess
Me2CdNOH. All other chemicals and solvents were obtained from
commercial sources and were used as received. C, H, and N elemental
analyses were carried out by the Microanalytical Service, Universidad
Auto´noma de Madrid. Electron impact mass spectra (EI-MS) were
obtained with a VG Autospec instrument. Decomposition points were
determined in capillary. Infrared spectra (4000-220 cm-1) were
recorded on a Perkin-Elmer 1650 FT-IR instrument, using Nujol mulls
between CsI windows. Raman spectra were measured on a Dilor XY
spectrophotometer, using an Ar laser (5145 Å) with the powdered
samples sealed in capillary tubes.
Synthetic Work and Characterization. Preparation of [PtCl2-
(OCMe2ONdCC4H8)2]. Solid MCPBA (1.02 g, 4.2-6.4 mmol) was
added in small portions during 15 min to a stirred suspension of trans-
[PtCl2({CH2}4CdNOH)2] (1.05 g, 2.3 mmol) in acetone (50 mL) at
room temperature. The suspension was converted into a dark-orange
solution 8-10 min after the beginning of the addition. The solution
was left to stand in an open beaker at 20-25 °C. After evaporation of
35-40 mL (ca. 12 h), released crystals were collected on a filter,
washed with acetone (2 × 1 mL) and diethyl ether (2 × 1 mL), and
dried in air at 20-25 °C. Yield of [PtCl2(OCMe2ONdCC4H8)2] )
0.72 g, 55% based on Pt. Complexes [PtCl2(OCMe2ONdCMe2)2] and
[PtCl2(OCMe2ONdCC5H10)2] were prepared analogously in 48 and 60%
yields, respectively. All three compounds were obtained as bright-
yellow crystals which are very poorly soluble in most common solvents.
The latter property does not allow the measurement of NMR spectra
of the complexes even with high accumulation.
a R1 ) ∑(|Fo| - |Fc|)/∑|Fo|. b wR2 ) [∑w(Fo - Fc2)2/∑wFo ]1/2
.
2
4
cm-1): 1672 m-w νs(CdN), 328 vs νs(Pt-Cl). Crystals suitable for
X-ray crystallography were grown directly from the reaction mixture.
X-ray Structure Determination of trans-[PtCl2(OCMe2-
ONdCC4H8)2] and trans-[PtCl2(OCMe2ONdCC5H10)2]. (Data for
the latter complex are given below in square brackets.) Diffraction
data were collected on an Enraf-Nonius CAD 4 diffractometer. Cell
parameters for both complexes were obtained from centered reflections
with θ between 10 and 12.5°; 1891 [1448] independent reflections were
measured up to 50° by the θ/2θ scan technique. Range of hkl: h )
-9 to +9, k ) -9 to +9, l ) -10 to 0 [h ) -14 to +14, k ) 0 to 11,
l ) 0 to 18]. Standard reflections were measured every 60 min and
showed practically no change with time ((1%). Diffractometer data
were processed by the program PROFIT19 with profile analysis of
reflections. The structures were solved by means of Fourier synthesis
based upon the Pt-atom coordinates obtained from the Patterson
synthesis using the SHELXTL package.20a After that, all reflections
with I < 3σ(I) were excluded from calculations. Refinement was done
by full-matrix least squares based on F2 using the SHELX-93
package.20b All non-H atoms were treated anisotropically. H atoms
were located in a difference Fourier map and refined isotropically
[hydrogen coordinates were found from difference synthesis and were
included in refinement with fixed coordinates and thermal parameters].
An extinction correction has been applied. Lorentz, polarization, and
absorption corrections were made.21 Crystal size: 0.28 × 0.24 × 0.20
[0.15 × 0.12 × 0.12] mm. Tmin and Tmax are 0.154 and 0.301 [0.197
and 0.302], respectively. Scattering factors were obtained from ref 22.
Crystal data are given in Table 1, atomic parameters are given in Tables
2 and 3, and bond distances and angles are given in Tables 4 and 5.
[PtCl2(OCMe2ONdCC4H8)2] has no characteristic melting point. On
heating it decomposes from ca. 120 °C. Anal. Calcd for C16H28-
Cl2N2O4Pt: C, 33.2; H 4.9; N 4.8. Found: C, 33.1; H 5.2; N 4.7.
EI-MS, m/z: 563 ([M - CH3]+). IR (selected bands, cm-1): 1635 m
νas(CdN), 337 m-s νas(Pt-Cl). Raman spectrum (selected bands,
cm-1): 1640 m-w νs(CdN), 324 vs νs(Pt-Cl). Crystals suitable for
X-ray crystallography were grown directly from the reaction mixture.
[PtCl2(OCMe2ONdCMe2)2] has no characteristic melting point. On
heating it decomposes from ca. 160 °C. Anal. Calcd for C12H24-
Cl2N2O4Pt: C, 27.4; H 4.6; N 5.3. Found: C, 26.7; H 4.2; N 5.0.
EI-MS, m/z: 511 ([M - CH3]+). IR (selected bands, cm-1): 1639 m
νas(CdN), 334 m-s νas(Pt-Cl). Raman spectrum (selected bands,
cm-1): 1648 m-w νs(CdN), 327 vs νs(Pt-Cl).
Discussion
The reaction between trans-[PtCl2(RR′CdNOH)2] and an
excess of MCPBA proceeds in a similar way for all three
complexes studied. The process is fast at room temperature,
and complete disappearance of the starting material was detected
by TLC monitoring a few minutes after mixing the reagents.
Crystals of the final products were released from the reaction
mixtures after 3-12 h, and compounds were isolated in 50-
(19) Strel’tsov, V. A.; Zavodnik, V. E. Kristallografiya 1989, 34, 1369.
(20) (a) Sheldrick, G. M. SHELXTL User Manual, Revision 3; Nicolet
XRD Corp.: Cupertino, CA, 1981. (b) Sheldrick, G. M. SHELX-93;
University of Go¨ttingen: Go¨ttingen, Germany, 1993.
(21) Axelrud, L. G.; Grin, Yu. N.; Zavalii, P. Yu.; Pecharsky, V. K.;
Fundamensky, V. S. CSD-universal program package for single crystal
and/or powder structure data treatment. Collected Abstracts, XII-th
European Crystallographic Meeting, Moscow, August 1989; p 155.
(22) International Tables for X-ray Crystallography; Kynoch Press:
Birmingham, U.K., 1974; Vol. IV.
[PtCl2(OCMe2ONdCC5H10)2] has no characteristic melting point.
On heating, it decomposes from ca. 130 °C. Anal. Calcd for
C18H32Cl2N2O4Pt: C, 35.7; H 5.3; N 4.6. Found: C, 35.7; H 5.3; N
4.6. EI-MS, m/z: 519 ([M - CH3]+). IR (selected bands, cm-1): 1668
m νas(CdN), 336 s νas(Pt-Cl). Raman spectrum (selected bands,
(18) Kukushkin, V. Yu.; Tudela, D.; Izotova, Yu. A.; Belsky, V. K.; Stash,
A. I. Unpublished results.

512 Inorganic Chemistry, Vol. 35, No. 2, 1996
Kukushkin et al.
Table 2. Atomic Coordinates (×104) and Equivalent Isotropic
Displacement Parameters (Å2 × 103) for
[PtCl2(OCMe2ONdCC4H8)2]a
Table 5. Bond Lengths (Å) and Angles (deg) for
[PtCl2(OCMe2ONdCC5H10)2]
Bond Lengths
Pt-O(1)
2.004(4)
2.3189(12)
1.51(2)
1.472(6)
1.489(8)
1.535(8)
1.518(9)
1.511(8)
O(1)-C(7)
1.382(6)
2.015(4)
1.21(2)
1.496(8)
1.523(9)
1.522(8)
1.538(8)
atom
x
y
z
Ueq
Pt-Cl
Pt-N
Pt
Cl
O(1)
O(2)
N
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
5000
5000
5000
27(1)
46(1)
39(1)
39(1)
32(1)
33(1)
46(1)
51(1)
43(1)
41(1)
39(1)
53(1)
50(1)
O(2)-N
N-C(1)
2073(1)
4727(3)
5309(3)
4050(3)
2939(3)
2131(4)
1115(5)
575(4)
2241(4)
4636(4)
5913(5)
2666(4)
4004(1)
7168(2)
7571(2)
5357(3)
4299(3)
2319(4)
1673(4)
3198(4)
4871(4)
8186(3)
10082(4)
8003(4)
3147(1)
7960(2)
5457(2)
7006(3)
7526(3)
6723(4)
7928(5)
8689(4)
8970(3)
6758(3)
7818(5)
6111(4)
O(2)-C(7)
C(1)-C(2)
C(2)-C(3)
C(4)-C(5)
C(7)-C(8)
C(1)-C(6)
C(3)-C(4)
C(5)-C(6)
C(7)-C(9)
Bond Anglesa
O(1)-Pt-O(1)#1 180.0
O(2)-N-Pt
O(1)-Pt-N#1
103.6(11)
96.6(7)
89.60(12)
89.6(3)
113.8(3)
114.3(7)
126.7(10)
113.1(5)
O(1)-Pt-N
O(1)-Pt-Cl
N-Pt-Cl
83.4(7)
90.40(12) O(1)#1-Pt-Cl
90.4(3)
180.0
110.2(5)
142(2)
117.4(11)
N#1-Pt-Cl
Cl#1-Pt-Cl
C(7)-O(2)-N
C(1)-N-Pt
N-C(1)-C(2)
C(7)-O(1)-Pt
C(1)-N-O(2)
N-C(1)-C(6)
C(8)-C(7)-C(9)
a Ueq is defined as one-third of the trace of the orthogonalized Uij
tensor.
Table 3. Atomic Coordinates (×104) and Equivalent Isotropic
Displacement Parameters (Å2 × 103) for
C(2)-C(1)-C(6)
C(4)-C(3)-C(2)
C(4)-C(5)-C(6)
115.8(5)
110.9(5)
111.4(5)
C(1)-C(2)-C(3)
C(5)-C(4)-C(3)
C(1)-C(6)-C(5)
108.1(5)
111.2(5)
109.0(4)
[PtCl2(OCMe2ONdCC5H10)2]a
O(1)-C(7)-O(2) 110.1(4)
O(1)-C(7)-C(8) 110.0(4)
atom
x
y
z
Ueq
O(2)-C(7)-C(8)
O(2)-C(7)-C(9)
a Symmetry transformations used to generate equivalent atoms: #1
104.2(4)
106.8(4)
O(1)-C(7)-C(9) 112.2(4)
Pt
Cl
O(1)
O(2)
N
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
5000
5000
5000
25(1)
40(1)
34(1)
33(1)
33(1)
30(1)
39(1)
45(1)
48(1)
45(1)
38(1)
33(1)
45(1)
48(1)
6094(1)
4840(3)
6613(3)
6277(3)
6802(4)
6510(5)
6194(5)
7094(6)
7380(5)
7685(4)
5661(4)
6048(5)
5342(5)
5799(2)
7011(4)
6519(5)
4966(28)
4167(7)
2620(6)
2181(6)
2533(7)
4113(6)
4582(6)
7438(6)
8918(6)
7316(8)
6030(1)
4624(2)
4447(2)
4457(2)
4133(3)
4113(3)
3319(3)
2881(3)
2932(3)
3715(3)
4252(3)
4494(3)
3429(3)
-x + 1, -y + 1, -z + 1.
Scheme 2
a Ueq is defined as one-third of the trace of the orthogonalized Uij
tensor.
IR spectra, and X-ray data are in agreement with the proposed
structure of Pt(IV) complexes with two newly formed chelate
ligands; see Scheme 2.
Table 4. Bond Lengths (Å) and Angles (deg) for
[PtCl2(OCMe2ONdCC4H8)2]
Compounds trans-[PtCl2(OCMe2ONdCC4H8)2], 1, and trans-
[PtCl2(OCMe2ONdCC5H10)2], 2, have been structurally char-
acterized. The coordination polyhedron of the complexes is a
slightly distorted octahedron (Figures 1 and 2). The Pt atom
in each case lies at an inversion center, and the two Cl atoms
are mutually trans. The values of the Pt-Cl bond distances
(2.312(1) for 1 and 2.319(1) Å for 2) agree well with previously
characterized platinum(IV) chloride compounds.23 Two chelate
ligands are trans, and the cycles containing the Pt atom are in
an envelope-like conformation. In 1, atoms Pt, N, C(6), and
O(2) are coplanar within 0.02 Å, the deviation of O(1) from
this plane being 0.55 Å. In 2, atoms Pt, N, C(7), and O(1) are
coplanar within 0.03 Å, and O(2) deviates from this plane by
0.6 Å. In the cyclopentanone oxime moiety of 1, the atoms
C(1), C(2), C(4), and C(5) are coplanar in the limits of 0.08 Å,
and atom C(3) deviates from this plane by 0.54 Å. The
cyclohexanone oxime ring of 2 adopts a chairlike conformation;
atoms C(1), C(2), C(4), and C(5) are coplanar within 0.01 Å,
and atoms C(3) and C(6) deviate by -0.68 and 0.66 Å,
correspondingly. The X-ray structures for Pt(IV) complexes
containing an oxime O-NdCRR′ fragment are unknown.
Nevertheless, the Pt-N interatomic distances in 1 and 2 are
2.007(2) and 2.015(4) Å, respectively, which is consistent with
those in the platinum(II) complex [PtCl(N,N-N(dCMe2)C2H4-
Bond Lengths
Pt-O(2)
Pt-N
2.007(2)
2.007(2)
2.3124(12)
1.396(3)
1.392(3)
1.475(3)
1.276(3)
C(1)-C(2)
C(2)-C(3)
C(4)-C(5)
C(6)-C(8)
C(6)-C(7)
C(1)-C(5)
C(3)-C(4)
1.489(4)
1.529(4)
1.529(4)
1.518(4)
1.511(4)
1.493(3)
1.518(4)
Pt-Cl
O(1)-N
O(2)-C(6)
O(1)-C(6)
N-C(1)
Bond Anglesa
O(2)-Pt-O(2)#1
O(2)-Pt-Cl
180.0
92.16(7)
180.0
O(2)-Pt-N#1
99.90(8)
80.10(8)
87.84(7)
92.16(7)
107.9(2)
115.7(2)
110.78(14)
125.0(2)
103.3(2)
103.6(2)
109.6(2)
104.0(2)
108.0(2)
O(2)-Pt-N
N#1-Pt-N
O(2)#1-Pt-Cl
O(2)-Pt-Cl#1
N-O(1)-C(6)
C(1)-N-O(1)
O(1)-N-Pt
N-Pt-Cl
90.54(7)
89.46(7)
113.2(2)
133.5(2)
123.7(2)
111.3(2)
104.3(2)
102.8(2)
109.2(2)
113.1(2)
112.6(2)
N-Pt-Cl#1
C(6)-O(2)-Pt
C(1)-N-Pt
N-C(1)-C(2)
C(2)-C(1)-C(5)
C(4)-C(3)-C(2)
C(1)-C(5)-C(4)
O(2)-C(6)-C(7)
O(2)-C(6)-C(8)
C(7)-C(6)-C(8)
N-C(1)-C(5)
C(1)-C(2)-C(3)
C(3)-C(4)-C(5)
O(2)-C(6)-O(1)
O(1)-C(6)-C(7)
O(1)-C(6)-C(8)
a Symmetry transformations used to generate equivalent atoms: #1
-x + 1, -y + 1, -z + 1.
60% yields. It is possible to assume that the initial reaction is
fast, but the formation of the final products must be slow
because, being quite insoluble, they should precipitate as soon
as they are formed. Elemental analyses, EI-MS, Raman and
(23) For X-ray structures of Pt(IV)-Cl complexes see, for example:
Kukushkin, V. Yu.; Zenkevich, I. G.; Belsky, V. K.; Konovalov, V.
E.; Moiseev, A. I.; Sidorov, E. O. Inorg. Chim. Acta 1989, 166, 79
and references therein.

Unusual Reactivity Mode of Coordinated Oximes
Inorganic Chemistry, Vol. 35, No. 2, 1996 513
C(7) bond lengths for 2 correspond to those in platinum
alkoxides.26 All other bond lengths in both trans-[PtCl2(OCMe2-
ONdCC4H8)2] and trans-[PtCl2(OCMe2ONdCC5H10)2] are
usual.
In conclusion, it is worthwhile to mention the following: (i)
we believe that the reactions reported here are the first oxidations
of Pt(II) involving the use of a peroxybenzoic acid. Previous
examples of the interaction of peroxybenzoic acids with
platinum complexes include only reactions of coordinated
ligands, e.g. oxygenation of the bridged sulfide in Pt2(µ-
27
S)(CO)2(PtBu2Ph)2 and Pt-C oxidative splitting in [Pt(CH2-
Ph)Cl(PPh3)2] with no change in the Pt(II) oxidation state.28
(ii) Accumulating data show that Me2CO, one of the most
common solvents, is far from being chemically inert. Both η1-
and η2-OdCMe2 coordination modes,29-31 η1 h η2 linkage
isomerization,31 template reactions,32 condensation with amines,24
deprotonation and bonding to a S22- bridged ligand,33 addition
to a (pyrazolyl)hydroborato ligand,34 and self-condensation with
the formation of HOCMe2CH2C(dO)Me35 and CH2dCMeCH2C-
(dO)Me36 chelate ligands have been reported. (iii) To the best
of our knowledge, no other example of metal-assisted ring
closure involving oxime ligands and ketones has been published
to date. Studies on the mechanism of this reaction and similar
reactions in other solvents37 are under current investigation.
Figure 1. View of [PtCl2(OCMe2ONdCC4H8)2] with atomic number-
ing.
Acknowledgment. The authors are grateful to the Spanish
Direccio´n General de Investigacio´n Cient´ıfica y Te´cnica for
financial support (Project PB93-0277) and the award of a
sabbatical fellowship to V. Yu. Kukushkin (Grant SAB 94-
0317). V. K. Belsky is grateful to the Russian Fund of
Fundamental Investigation for Grant 95-03-09030a. We thank
Professor G. Natile for a reprint of the work cited in ref 8. The
authors are much obliged to Youlia A. Izotova for experimental
assistance. Helpful comments from the referees are gratefully
acknowledged.
Supporting Information Available: Atomic coordinates and
equivalent isotropic displacement parameters (Tables 1 and 1a),
anisotropic displacement parameters (Tables 2 and 2a), and hydrogen
coordinates and isotropic displacement parameters (Tables 3 and 3a)
(3 pages). Ordering information is given on any current masthead page.
IC950351S
(26) Orpen, A. G.; Brammer, L.; Allen, F. H.; Kennard, O.; Watson, D.
G.; Taylor, R. J. Chem. Soc., Dalton Trans. 1989, S1.
(27) Browning, C. S.; Farrar, D. H. Organometallics 1989, 8, 813.
(28) Harvie, I. J.; McQuillin, F. J. J. Chem. Soc., Chem. Commun. 1977,
241.
(29) (a) Davies, J. A.; Hartley, F. R. Chem. ReV., 1981, 81, 79. (b) Bader,
A.; Nullmeyers, T.; Pabel, M.; Salem, G.; Willis, A. C.; Wild, S. B.
Inorg. Chem. 1995, 34, 384.
(30) Davies, J. A.; Hockensmith, C. M.; Kukushkin, V. Yu.; Kukushkin,
Yu. N. Synthetic Coordination Chemistry: Principles and Practice.
In press.
(31) Powell, D. W.; Lay, P. A. Inorg. Chem. 1992, 31, 3542.
(32) (a) House, D. A.; Curtis, N. F. J. Am. Chem. Soc. 1964, 86, 223. (b)
Curtis, N. F.; House, D. A. J. Am. Chem. Soc. 1964, 86, 1331 and
references therein.
Figure 2. View of [PtCl2(OCMe2ONdCC5H10)2] with atomic number-
ing.
NH2)(PBu3)]Cl (2.08(1) Å24 ) and in some oxime-containing
Pt(II) complexes (1.97-2.02 Å17,25 ). The C(6)-O(1) bond
length (1.475(3) Å) in 1 and C(7)-O(2) bond length (1.472(6)
Å) in 2 agree within 3σ with the C-O bond distance (1.55(3)
Å) found earlier in [PtCl2(N(dO)CMe2ONCMe2)].17 The Pt-
O(2) and O(2)-C(6) bond lengths for 1 and Pt-O(1) and O(1)-
(33) Matsumoto, K.; Uemura, H.; Kawano, M. Inorg. Chem. 1995, 34,
658.
(34) Looney, A.; Han, R.; Gorrell, I. B.; Cornebise, M.; Yoon, K.; Parkin,
G.; Rheinglod, A. L. Organometallics 1995, 14, 274.
(35) Li, Z.-W.; Harman, W. D.; Lay, P. A.; Taube, H. Inorg. Chem. 1994,
33, 3635.
(36) Izakovich, E. N.; Krasochka, O. N.; Rostchupkina, O. S.; Tkachev,
V. V. Metalloorg. Khim. 1988, 1, 424.
(37) Kukushkin, V. Yu.; Izotova, Yu. A.; Tudela, D. Unpublished results.
(24) Kozelka, J.; Bois, C. Inorg.Chem. 1988, 27, 3866.
(25) (a) Megnamisi-Belombe, M. J. Solid State Chem. 1979, 27, 389. (b)
Endres, H.; Megnamisi-Belombe, M.; Keller, H. J.; Weiss, J. Acta
Crystallogr., Sect. B 1976, 32, 457. (c) Ferraris, G.; Viterbo, D. Acta
Crystallogr., Sect. B 1969, 25, 2066. (d) Schelemper, E. O. Inorg.
Chem. 1969, 8, 2740. (e) Pritzkow, H. Z. Naturforsch. 1976, 31b, 401.
(f) Kaitano, Y.; Kobori, K.; Tanimura, M.; Kinoshita, Y. Bull. Chem.
Soc. Jpn. 1974, 47, 2969.