Oxidation of Pt-bound bis-hydroxylamine as a novel route to unexplored dinitrosoalkane ligated species

Article abstract of DOI:10.1021/ic800481a

The reaction of K₂[PtCl₄] and HO(H)NCMe ₂CMe₂N(H)OH·H₂SO₄ (BHA·H₂SO₄; 2) in a molar ratio 1:2 at 20-25° C in water affords a mixture of [Pt(BHA)₂][PtCl₄] (5) and [Pt(BHA-H)₂] (6) (BHA-H = anionic monodeprotonated form of BHA) which, upon heating at 80-85°C for 12 h or on prolonged keeping at 20-25°C for 2 weeks, is subject to a slow transformation giving [PtCl ₂(BHA)] (7). The latter compound is also obtained from the reaction between K[PtCl₃(Me₂Scombining minus sign belowO)] and 2. The chlorination of [PtCl₂(BHA)] (7) in freshly distilled dry chloroform leads to the selective oxidation of one N(H)OH group yielding [PtCl₂{HO(H)Ncombining minus sign belowCMe₂CMe ₂N=O}] (13), while the chlorination in water produces the complex [PtCl₂(O=Ncombining minus sign belowCMe₂CMe ₂Ncombining minus sign below=O)] (14) bearing the unexplored dinitrosoalkane species. Treatment of 14 with 2 equiv of 1,2-bis- (diphenylphosphino)ethane (dppe) in CH₂Cl₂ results in the liberation of the dinitrosoalkane ligand followed by its fast cyclization giving the α-dinitrone (3,3,4,4-tetramethyl-1,2-diazete-1,2-dioxide) in solution and the solid [Pt(dppe)₂](Cl)₂. The Pt^II complexes with hydroxylamino∩oximes [PtCl₂{HO(H)Ncombining minus sign belowC(Me)₂C(R)=Ncombining minus sign belowOH}] (R = Me 8; R = Ph 9) upon their oxidation with Cl₂ in CHCl₃ afford the nitrosoalkane derivatives [PtCl₂{O=Ncombining minus sign belowCMe₂C(R)=Ncombining minus sign belowOH}] (R = Me 16; Ph 17), respectively, while the corresponding chlorination of the bis-chelates [Pt{HO(H)Ncombining minus sign belowCMe₂C(R)=Ncombining minus sign belowOH}₂] (R = Me 10; Ph 11) gives [Pt{O=Ncombining minus sign belowCMe₂C(R)=Ncombining minus sign belowO}₂] (R = Me 18; Ph 19). The formulation of 5-19 is based on C, H, and N microanalyses, IR, 1D (¹H, ¹³C{¹H}, ¹⁹⁵Pt) and 2D ( ¹H,¹H-COSY,¹H,¹³C-HSQC) NMR spectroscopies, and X-ray diffraction for five complexes (5, 7, and 12-14).

Full text of DOI:10.1021/ic800481a

Inorg. Chem. 2008, 47, 6919-6930
Oxidation of Pt-bound Bis-hydroxylamine as a Novel Route to
Unexplored Dinitrosoalkane Ligated Species
Konstantin V. Luzyanin,†,‡ Pavel V. Gushchin,‡ Armando J. L. Pombeiro,*,† Matti Haukka,§
Victor I. Ovcharenko,| and Vadim Yu. Kukushkin*,‡,⊥
Centro de Qu´ımica Estrutural, Complexo I, Instituto Superior Te´cnico, TU Lisbon, AV. RoVisco
Pais, 1049-001 Lisbon, Portugal, St.Petersburg State UniVersity, 198504 Stary Petergof, Russian
Federation, Department of Chemistry, UniVersity of Joensuu, P.O. Box 111, FI-80101, Joensuu,
Finland, International Tomography Center, Institutskaya Str. 3a, 630090 NoVosibirsk, Russian
Federation, and Institute of Macromolecular Compounds of the Russian Academy of Sciences,
Bolshoii Pr. 31, 199004 St.Petersburg, Russian Federation
Received March 17, 2008
The reaction of K2[PtCl4] and HO(H)NCMe2CMe2N(H)OH · H2SO4 (BHA ·H2SO4; 2) in a molar ratio 1:2 at 20-25
°C in water affords a mixture of [Pt(BHA)2][PtCl4] (5) and [Pt(BHA-H)2] (6) (BHA-H ) anionic monodeprotonated
form of BHA) which, upon heating at 80-85 °C for 12 h or on prolonged keeping at 20-25 °C for 2 weeks, is
subject to a slow transformation giving [PtCl2(BHA)] (7). The latter compound is also obtained from the reaction
between K[PtCl3(Me2SO)] and 2. The chlorination of [PtCl2(BHA)] (7) in freshly distilled dry chloroform leads to the
selective oxidation of one N(H)OH group yielding [PtCl2{HO(H)NCMe2CMe2N)O}] (13), while the chlorination in
water produces the complex [PtCl2(O)NCMe2CMe2N)O)] (14) bearing the unexplored dinitrosoalkane species.
Treatment of 14 with 2 equiv of 1,2-bis-(diphenylphosphino)ethane (dppe) in CH2Cl2 results in the liberation of the
dinitrosoalkane ligand followed by its fast cyclization giving the R-dinitrone (3,3,4,4-tetramethyl-1,2-diazete-1,2-
dioxide) in solution and the solid [Pt(dppe)2](Cl)2. The PtII complexes with hydroxylamino∩oximes
[PtCl2{HO(H)NC(Me)2C(R))NOH}] (R ) Me 8; R ) Ph 9) upon their oxidation with Cl2 in CHCl3 afford the
nitrosoalkane derivatives [PtCl2{O)NCMe2C(R))NOH}] (R ) Me 16; Ph 17), respectively, while the corresponding
chlorination of the bis-chelates [Pt{HO(H)NCMe2C(R))NOH}2] (R ) Me 10; Ph 11) gives [Pt{O)NCMe2C(R))NO}2]
(R ) Me 18; Ph 19). The formulation of 5-19 is based on C, H, and N microanalyses, IR, 1D (1H, 13C{1H}, 195Pt)
and 2D (1H,1H-COSY,1H,13C-HSQC) NMR spectroscopies, and X-ray diffraction for five complexes (5, 7, and
12-14).
Introduction
are intriguing ligands in coordination chemistry giving metal-
containing systems which exhibit a variety of unusual
reactivity modes.3,4
The general chemistry of C-nitroso species, in particular,
nitrosoalkanes (for comprehensive reviews see refs 1,2)
became a subject of rapt attention after the recent discovery
of the important role of these compounds in various
biochemical metabolic processes. In addition, these species
In comparison with mononitrosoalkanes, the family of
dinitrosoalkanes (for a recent review see ref 2), especially
those with two nitroso groups in Vicinal or geminal position,
includes only a small number of representatives.2 This is
explained, on one hand, by the high reactivity of free
dinitrosoalkanes determining their short lifetime and involve-
ment in secondary reactions right after the generation. On
the other hand, methods for preparation of the dinitrosoal-
kanes are still undeveloped.
* To whom correspondence should be addressed. E-mail: pombeiro@
ist.utl.pt (A.J.L.P.), kukushkin@VK2100.spb.edu (V.Y.K.).
†
Instituto Superior Te´cnico.
St.Petersburg State University.
University of Joensuu.
International Tomography Center.
‡
§
|
⊥
Institute of Macromolecular Compounds.
(1) Gowenlock, B. G.; Richter-Addo, G. B. Chem. ReV. 2004, 104, 3315.
(2) Gowenlock, B. G.; Richter-Addo, G. B. Chem. Soc. ReV. 2005, 34,
797.
(3) Lee, J.; Chen, L.; West, A. H.; Richter-Addo, G. B. Chem. ReV. 2002,
102, 1019.
10.1021/ic800481a CCC: $40.75  2008 American Chemical Society
Inorganic Chemistry, Vol. 47, No. 15, 2008 6919
Published on Web 06/27/2008

Luzyanin et al.
To our knowledge, the coordination chemistry of dini-
trosoalkanes is at the very early stage of its growth, and metal
dinitrosoalkane derivatives are so far represented exclusively
by the series of cobalt(I) complexes of type [Co(η5-
Cp)(O)NCR1R2CR3R4N)O)] (R1, R,2 R3, R4 ) H, Me, Et,
Ph, C3H8) and the dimer [{Co(η5-Cp)}2(C7H8(NdO)4)], and
the ruthenium(II/III) [Ru(O)NCMe2CMe2N)O)(bpy)2]2+/
3+(bpy ) 2,2′-bipyridine) species. The cobalt complexes
were generated via a multicomponent reaction of [Co(η5-
Cp)(CO)2] with a Diels-Alder adduct of cyclopentadiene
and the dimethyl ester of acetylenedicarboxylic acid in the
presence of NO,5 or via the addition of alkenes to [Co(η5-
Cp)(NO)]2.5 The ruthenium complex originated from
the oxidation of [Ru(bpy)2(NH2CMe2CMe2NH2)]2+ by
Figure 1. Bis-hydroxylamine and hydroxylamino∩oximes employed for
this study.
(albeit aromatic rather than aliphatic) have been synthesized
by oxidation of N-substituted hydroxylamines by ferric
chloride,15 pyridinium chlorochromate,16 or Bu hypochlo-
t
rite;15 (ii) 1,2-hydroxylamino-2,3,5,6-tetrachlorobenzene was
selectively oxidized to 1,2-nitroso-2,3,5,6-tetrachlorobenzene.2
As a metal center for this study we addressed platinum(II)
insofar as it gives kinetically inert metal complexes, and this
property allows the trapping of species which are unstable
or even elusiVe in the free state. In addition, it is our
experience that PtII centers strongly stabilize ligated
nitrosoalkanes.8,9
Ce(NO3)6 in CF3CO2H.6 The years passed since the
2-
preparation of these complexes did not bring any further
dinitrosoalkane metal compounds that give a collateral
evidence that the observed synthetic routes to the dinitroso
systems are more specific than general.
In view of our ongoing interest on the coordination
chemistry of compounds with N-O and NdO bonds as
ligands (including nitrosoalkanes),7–10 nucleophiles,11 pro-
moters12 or dipoles,13 we endeavored to discover a novel
route to dinitrosoalkane metal derivatives. The hypothesis
of this work was to employ for the study the metal-bound
bis-hydroxylamine ligand (1 in Figure 1; an efficient
synthesis of 1 was developed by one of us14) and to conduct
its intramolecular oxidation to achieve the dinitrosoalkane
chelates. This starting idea was supported by the following
previous works: (i) some metal-free C-nitroso compounds
The scenario for this work was the following. First, to
synthesize novel (bis-hydroxylamino)PtII complexes. Second,
to attempt the stepwise selective oxidation of the prepared
species to achieve mixed hydroxylamino/nitrosolkane sys-
tems and then the dinitroso ligand. Third, to liberate the
dinitrosoalkane ligand and to study its stability in the free
state and/or its conversions. Fourth, to compare the oxidation
of the (bis-hydroxylamino)PtII complexes with that of
(hydroxylamino∩oximes)PtII compounds; the latter are based
on the ligands 3 and 4 depicted in Figure 1. Details of the
obtained results are elaborated in this article.
(4) Cameron, M.; Gowenlock, B. G.; Vasapollo, G. Chem. Soc. ReV. 1990,
19, 355.
Results and Discussions
(5) (a) Brunner, H.; Loskot, S. Angew. Chem., Int. Ed. Engl. 1971, 10,
515. (b) Evrard, G.; Thomas, R.; Davis, B. R.; Bernal, I. J. Organomet.
Chem. 1977, 124, 59. (c) Becker, P. N.; Bergman, R. G. Organome-
tallics 1983, 2, 787. (d) Becker, P. N.; Bergman, R. G. J. Am. Chem.
Soc. 1983, 105, 2985.
SynthesisandCharacterizationof{HO(H)N-C∩C-N(H)-
OH}PtII-Type Chelates. The complexation of various hy-
droxylamines to PtII and PtIV centers is well-known, and
species with unsubstituted,17 N-substituted,18 and N,N-
disubstituted hydroxylamines19 were described in the litera-
ture. In spite of the reported variety of monodentate Pt-bound
hydroxylamine ligands, platinum(II) complexes with N,N-
bidentate ligands having two hydroxylamine binding sites
have never been reported in the past. Moreover, up to date
the only documented example of metal complexes bearing
(6) Chiu, W.-H.; Cheung, K.-K.; Che, C.-M. J. Chem. Soc., Chem.
Commun. 1995, 441.
(7) For reviews see: (a) Kukushkin, V.Yu.; Pombeiro, A. J. L. Coord.
Chem. ReV. 1999, 181, 147. (b) Kukushkin, V.Yu.; Tudela, D.;
Pombeiro, A. J. L. Coord. Chem. ReV. 1996, 156, 333. (c) Pombeiro,
A. J. L.; Kukushkin, V.Yu. Reactions of Coordinated Oximes. In
ComprehensiVe Coordination Chemistry, 2nd ed.; Elsevier: New York,
2004; Vol. 1, Chapter 1.33, pp 631-637.
(8) Kukushkin, V.Yu.; Belsky, V. K.; Aleksandrova, E. A.; Konovalov,
V. E.; Kirakosyan, G. A. Inorg. Chem. 1992, 31, 3836.
(9) Kukushkin, V.Yu.; Tudela, D.; Izotova, Y. A.; Belsky, V. K.; Stash,
A. I. Inorg. Chem. 1996, 35, 4926.
(13) (a) Wagner, G.; Pombeiro, A. J. L.; Kukushkin, V.Yu. J. Am. Chem.
Soc. 2000, 122, 3106. (b) Wagner, G.; Haukka, M.; Frau´sto da Silva,
J. J. R.; Pombeiro, A. J. L.; Kukushkin, V.Yu. Inorg. Chem. 2001,
40, 264. (c) Bokach, N. A.; Khripoun, A. V.; Kukushkin, V.Yu.;
Haukka, M.; Pombeiro, A. J. L. Inorg. Chem. 2003, 42, 896. (d)
Charmier, M. A. J.; Kukushkin, V.Yu.; Pombeiro, A. J. L. J. Chem.
Soc., Dalton Trans. 2003, 2540. (e) Bokach, N. A.; Kukushkin, V.Yu.;
Haukka, M.; Pombeiro, A. J. L. Eur. J. Inorg. Chem. 2005, 845. (f)
Bokach, N. A.; Krokhin, A. V.; Nazarov, A. A.; Kukushkin, V.Yu.;
Haukka, M.; Frau´sto da Silva, J. J. R.; Pombeiro, A. J. L. Eur. J. Inorg.
Chem. 2005, 44, 3042. (g) Makarycheva-Mikhailova, A. V.; Go-
lenetskaya, J. A.; Bokach, N. A.; Balova, I. A.; Haukka, M.;
Kukushkin, V.Yu. Inorg. Chem. 2007, 46, 8323.
(10) Luzyanin, K. V.; Kukushkin, V.Yu.; Kuznetsov, M. L.; Ryabov, A. D.;
Galanski, M.; Haukka, M.; Tretyakov, E. V.; Ovcharenko, V. I.;
Kopylovich, M. N.; Pombeiro, A. J. L. Inorg. Chem. 2006, 45, 2296.
(11) For reviews see: (a) Kukushkin, V.Yu.; Pombeiro, A. J. L. Chem.
ReV. 2002, 102, 1771. (b) Pombeiro, A. J. L.; Kukushkin, V. Yu.
Reactions of Coordinated Nitriles. In ComprehensiVe Coordination
Chemistry, 2nd ed.; Lever, A. B. P., Ed.; Elsevier: New York, 2004;
Vol. 1, Chapter 1.34, pp. 639-660.
(12) (a) Kopylovich, M. N.; Kukushkin, V.Yu.; Guedes da Silva, M. F. C.;
Haukka, M.; Frau´sto da Silva, J. J. R.; Pombeiro, A. J. L. J. Chem.
Soc., Perkin Trans. 2001, 1, 1569. (b) Kopylovich, M. N.; Pombeiro,
A. J. L.; Fischer, A.; Kloo, L.; Kukushkin, V.Yu. Inorg. Chem. 2003,
42, 7239. (c) Kopylovich, M. N.; Kukushkin, V.Yu.; Haukka, M.;
Luzyanin, K. V.; Pombeiro, A. J. L. J. Am. Chem. Soc. 2004, 126,
15040. (d) Kopylovich, M. N.; Haukka, M.; Kirillov, A. M.;
Kukushkin, V.Yu.; Pombeiro, A. J. L. Chem.sEur. J. 2007, 13, 786.
(e) Luzyanin, K. V.; Kukushkin, V.Yu.; Kopylovich, M. N.; Nazarov,
A. A.; Galanski, M.; Pombeiro, A. J. L. AdV. Synth. Catal. 2008, 350,
135.
(14) Ovcharenko, V. I.; Fokin, S. V.; Romanenko, G. V.; Korobkov, I. V.;
Rey, P. Russ. Chem. Bull. 1999, 48, 1519.
(15) (a) Entwistle, I. D.; Gilkerson, T.; Johnstone, R. A. W.; Telford, R. P.
Tetrahedron 1978, 34, 213. (b) Wood, W. W.; Wilkin, J. A. Synth.
Commun. 1992, 22, 1683. (c) Davey, M. H.; Lee, V. Y.; Miller, R. D.;
Marks, T. J. J. Org. Chem. 1999, 64, 4976.
(16) Wood, W. W.; Wilkin, J. A. Synth. Commun. 1992, 22, 1683.
6920 Inorganic Chemistry, Vol. 47, No. 15, 2008

Oxidation of Pt-bound Bis-hydroxylamine
Scheme 1
the bifunctional hydroxylamine concerns the nickel(II) che-
late [NiCl(BHA-H)(BHA)]20 (BHA is 1, IUPAC name21 is
N2,N3-dihydroxy-2,3-dimethylbutane-2,3-diamine; BHA-H is
anionic monodeprotonated form of BHA), synthesized by
one of us.14
We have now found that the reaction of K2[PtCl4] and
BHA · H2SO4 (2) in a molar ratio 1:2 at 20-25 °C in water
affords a mixture of the red crystalline solid [Pt(BHA)2]-
[PtCl4] (5) and the colorless amorphous [Pt(BHA-H)2] (6),
(Scheme 1, Route 1A), from which 5 was separated in 37%
yield. When the synthesis is performed in D2O, the monitor-
ing of the filtrate using 2D 1H,1H-COSY, and1H,13C-HSQC
NMR correlation experiments, allowed the identification of
dissolved 5 and 6 along with [PtCl2(BHA)] (7). Our attempts
to isolate some additional amounts of 5 from the filtrate were
unsuccessful insofar as it is strongly contaminated with other
products because of similar and rather high water solubilities
of the components of the mixture.
The (BHA)PtII complexes were also obtained starting from
the sulfoxide precursor K[PtCl3(Me2SO)]22 (prepared via
Route 1B). Thus, reaction of equimolar amounts of
K[PtCl3(Me2SO)] and BHA· H2SO4 furnishes the solid
[PtCl2(BHA)] (7) isolated in 45% yield (Route 1C). The
latter compound was also prepared from K2[PtCl4] or cis-
[PtCl2(Me2SO)2] and 2 equiv BHA· H2SO4 but in lower
yields (28 and 22%, respectively, Routes 1E and 1F).
However, in both latter cases the process is not selective
and affords 7 strongly contaminated with other products (in
particular with 5 and 6) and, in the case of Route 1F, also
with cis-[PtCl2(Me2S)2] (crystals of this sulfide complex
released from the reaction mixture were subject to X-ray
diffraction and the structure solution indicated a good
agreement with the known structure of cis-[PtCl2(Me2S)2],23
see Supplementary Information). The bis-sulfide complex
derives from the known deoxygenation of the sulfoxide
precursor by hydroxylamine.24
(17) (a) Grinberg, A. A.; Stetsenko, A. I. Zh. Neorg. Khim. 1961, 6, 111.
(b) Stetsenko, A. I.; Nefedov, V. I.; Abzaeva, T. G.; Salyn, Ya. V.
Russ. Chem. Bull. 1974, 3, 530. (c) Kukushkin, V.Yu.; Stetsenko, A. I.;
Duibanova, V. G.; Strelin, S. G. Zh. Neorg. Khim. 1974, 19, 2803.
(d) Stetsenko, A. I.; Abzaeva, T. G.; Mitkinova, N. D.; Pogoreva,
V. G.; Konovalov, L. V.; Barsukov, A. V. Zh. Neorg. Khim. 1976,
21, 182. (e) Tikhonova, L. S.; Stetsenko, A. I. Zh. Neorg. Khim. 1988,
33, 2324. (f) Tulub, A. D.; Stetsenko, A. I. Zh. Neorg. Khim. 1989,
34, 902. (g) Vorob’ev-Desyatovskii, N. V.; Kukushkin, V.Yu.; Lukin,
Yu.N.; Patrabansh, K. M.; Morozov, N. L. Zh. Obshch. Khim. 1990,
60, 266. (h) Slyudkin, O. P.; Khlestkin, V. K.; Tikhonov, A.Ya.;
Baidina, I. A. Zh. Neorg. Khim. 2003, 48, 1623. (i) Zorbas-Seifried,
S.; Jakupec, M. A.; Kukushkin, N. V.; Groessl, M.; Hartinger, C. G.;
Semenova, O.; Zorbas, H.; Kukushkin, V.Yu.; Keppler, B. K. Mol.
Pharmacol. 2007, 71, 357.
The mixture of 5 and 6 (obtained via Route 1A), upon
heating at 80-85 °C for 12 h or on prolonged keeping at
20-25 °C for 2 weeks, is subject to a slow transformation
giving 7 (Route 1G). The reaction of K2[PtCl4] and the
free base N2,N3-dihydroxy-2,3-dimethylbutane-2,3-diamine
(BHA, 1) in various molar ratios ranging from 1:1 to 1:2 in
water does not achieve 5-7 but results in the formation of
a mixture of yet unidentified products, including platinum
black (which originates form the reduction of Pt-containing
species), while the corresponding reaction of K[PtCl3-
(Me2SO)] or cis-[PtCl2(Me2SO)2] with BHA also in aqueous
(18) (a) Stetsenko, A. I.; Strelin, S. G. Zh. Neorg. Khim. 1973, 18, 2642.
(b) Bedrina, M. E.; Sarukhanov, M. A.; Parpiev, N. A. Koord. Khim.
1975, 1, 659. (c) Sarukhanov, M. A.; Stetsenko, A. I. Zh. Neorg. Khim.
1975, 20, 217. (d) Val’dman, S. S.; Nasirdinov, S. D.; Sharipov, Kh.T.
Zh. Neorg. Khim. 1985, 30, 159.
(19) (a) Kuz’mina, L. G.; Porai-Koshits, M. A.; Vorob’ev-Desyatovskii,
N. V. Zh. Obshch. Khim. 1992, 62, 1921. (b) Vorob’ev-Desyatovskii,
N. V.; Ravdel, B. A.; Skvortsov, N. K.; Shcherbak, Yu. S.; Nikolaev,
A. V.; Batorova, G. N. Zh. Obshch. Khim. 1992, 62, 1928.
(20) Fokin, S. V.; Romanenko, G. V.; Ovcharenko, V. I. MendeleeV
Commun. 2001, 127.
(22) Kukushkin, V. Y.; Pombeiro, A. J. L.; Ferreira, C. M. P.; Elding, L. I.
Inorg. Synth. 2002, 33, 189.
(23) Horu, G. W.; Kumar, R.; Maverick, F. R.; Fronczek, F. R.; Watkins,
S. F. Acta Crystallogr., Sect. C 1990, 46, 135.
(21) http://www.iupac.org/nomenclature/index.html.
(24) Lardon, H.; Seybold, G. Patent EP-68371, Jan 05, 1983.
Inorganic Chemistry, Vol. 47, No. 15, 2008 6921

Luzyanin et al.
Figure 3. Thermal ellipsoid view of complex 7 with atomic numbering
scheme. Thermal ellipsoids are drawn with 50% probability. Selected bond
lengths (Å) and angles (deg): Pt(1)-N(1) 2.027(9), Pt(1)-N(2) 2.027(9),
Pt(1)-Cl(1) 2.311(3), Pt(1)-Cl(2) 2.310(3), O(1)-N(1) 1.423(11), O(2)-N(2)
1.436(11), N(1)-Pt(1)-N(2) 83.0(3), N(2)-Pt(1)-Cl(1) 91.9(3).
Figure 2. Thermal ellipsoid view of 5 with atomic numbering scheme
(hydrogen labels are not shown for simplicity). Thermal ellipsoids are drawn
with 50% probability. Selected bond lengths (Å) and angles (deg):
Pt(1)-N(1) 2.038(5), Pt(1)-N(2) 2.042(5), Pt(2)-Cl(1) 2.2833(17),
Pt(2)-Cl(2) 2.2912(16), O(1)-N(1) 1.431(6), O(2)-N(2) 1.428(6),
N(2)-Pt(1)-N(1) 82.5(2), N(2)#1-Pt(1)-N(1)#1 82.5(2). Symmetry trans-
formations used to generate equivalent atoms: #1 ) -x + 3/2, -y + 1/2,
-z + 1.
ing rings (similar to those observed in the related PtN4
chelates,27,28 for example, [Pt{HONC(Me)C(Me)NO}2]27),
and the 2+ charge on the cation is compensated by the charge
on the anion [PtCl4]2-. The bond lengths Pt(1)-N(1) 2.038(5)
and Pt(1)-N(2) 2.042(5) Å are normal while O(1)-N(1)
1.431(6) and O(2)-N(2) 1.428(6) Å are equal within 3σ and
belong to typical single O-N bonds.29 The N(2)-Pt(1)-N(1)
angle is 82.46(18)°, and this value compares well with those
previously observed in the nickel chelate [NiCl(BHA)(BHA-
H)] [84.0(3)-84.7(3)°].20 Examination of the distances and
angles between the hydroxylamine OH proton (H2O) of one
chelated ligand and the hydroxylamine oxygen (O1) of
another chelated ligand indicates the existence of two
symmetric intramolecular hydrogen bonds between two
chelated groups, stabilizing the structure of 5, with the
following observed distances and angles: O(2)-H(2O) 0.83,
O(2)-H(2O) · · · O(1) 1.88 Å, O(2)-H(2O) · · · O(1) 155.1°.
A similar type of intramolecular H-bonding was also
observed in relevant bis-chelate complexes with MN4 square-
planar coordination environment, namely, in [Pt{HONC(Me)-
C(Me)NO}2], [Pd{HON(1,2-C6H4)NO}2], and [Ni{HONC(d
O)C(dO)NO}2]; the hydrogen bonding distance is 1.62-1.92
Å,27 1.51-1.77 Å,30 and 1.65 Å,31 respectively.
media affords cis-[PtCl2(Me2S)2]23 via the deoxygenation of
the coordinated dimethyl sulfoxide by the N(H)OH centers
of BHA.24
The formulation of complexes 5 and 7 was supported by
satisfactory C, H, and N microanalyses. The complexes were
also characterized by IR and 1D 1H, 13C{1H}, 195Pt, and 2D
1H,1H-COSY,1H,13C-HSQC NMR spectroscopies, and X-ray
crystallography.
The IR spectra of 5 and 7 exhibit two strong bands in the
range of 3220-2990 cm-1 due to the ν(N-H) and ν(O-H)
stretching vibrations of the hydroxylamine moieties. The 1H
NMR spectrum of 7 displays two broad singlets from the
NH and OH protons of the hydroxylamine HO(H)N groups
at about 7.7 and 9.5 ppm, respectively. In the 13C{1H} spectra
of 5 in D2O and 7 in DMSO-d6, the CN carbon resonates in
the expected field at about 72-77 ppm.25 The 195Pt NMR
spectra of 5 in D2O and 7 in DMSO-d6, display one peak
between -2450 and -2500 ppm in the typical range for PtII
species.26 In the 195Pt NMR spectrum of 5 in D2O, one more
signal due to the anion [PtCl4]2- emerging at -1713 ppm
was detected.
(27) (a) Frasson, E.; Panatonni, C.; Zanetti, R. Acta Crystallogr. 1959, 12,
1027. (b) Hussain, M. S.; Salinas, B. E. V.; Schlemper, E. O. Acta
Crystallogr., Sec. B 1979, 25, 628. (c) Konno, M.; Okamoto, T.;
Shirotani, I. Acta Crystallogr., Sec. B 1989, 45, 142. (d) Shirotani, I.;
Konno, M.; Taniguchi, Y. Synth. Met. 1989, 29, F123.
The structures of 5 and 7 have been determined by X-ray
diffraction (Figures 2 and 3). In 5, the coordination polyhedra
of both platinum centers are slightly distorted squares. In
the cation, two neutral BHA ligands are coordinated by both
hydroxylamino N atoms forming two five-membered chelat-
(28) (a) Branco, J. L.; de Matheus, M. Afinidad 1982, 39, 271. (b) Endres,
H. Acta Crystallogr., Sect C. 1985, 41, 1047. (c) Ferraris, G.; Viterbo,
D. Acta Crystallogr., Sect. B. 1969, 25, 2066. (d) Kanakubo, M.;
Yamamoto, K.; Honda, K.; Ushijima, H.; Kamata, T.; Mizukami, F.;
Ohta, T. Anal. Sci. 1999, 15, 107.
(29) (a) Orpen, A. G.; Brammer, L.; Allen, F. H.; Kennard, O.; Watson,
D. G.; Taylor, R. J. Chem. Soc., Dalton Trans. 1989, S1. (b) Allen,
F. H.; Kennard, O.; Watson, D. G.; Brammer, L.; Orpen, A. G.; Taylor,
R. J. Chem. Soc., Perkin Trans. 2 1987, S1.
(25) (a) Silverstein, R. M.; Bassler, G. C.; Morrill, T. C. Spectrometric
Identification of Organic Compounds; Wiley: New York, 1991. (b)
Breitmaier, E.; Bauer, G. 13C-NMR spectroscopy - A working manual
with exercises; Harwood Academic: New York, 1984; p 354. (c) Balci,
M. Basic 1H and 13C-NMR spectroscopy; Elsevier Science: New
York, 2005; p 440; http://chemgate.emolecules.com/.
(30) (a) Leichert, I.; Weiss, J. Acta Crystallogr., Sect. B. 1975, 31, 2709.
(b) Endres, H.; Megnamisi-Belombe, M.; Little, W. A.; Wolfe, C. R.
Acta Crystallogr., Sect. B. 1979, 25, 169. (c) Kistenmacher, T. J.;
Destro, R. Inorg. Chem. 1983, 22, 2104.
(26) Still, B. M.; Kumar, P. G. A.; Aldrich-Wright, J. R.; Price, W. S.
Chem. Soc. ReV. 2007, 36, 665.
(31) Moroz, Y. S.; Gumienna-Kontecka, E.; Fritsky, I. O.; Ondarenko, I. M.;
Swiatek-Kozlowska, J. Acta Crystallogr., Sect. C. 2006, 62, m498.
6922 Inorganic Chemistry, Vol. 47, No. 15, 2008

Oxidation of Pt-bound Bis-hydroxylamine
Scheme 2
Complex 7, [PtCl2(BHA)], is the first crystallographic
evidence for monochelate metal complexes with two bonded
hydroxylamine sites. In 7, the coordination polyhedron of
the metal center is a slightly distorted square, and the neutral
BHA ligand is coordinated by both hydroxylamino N atoms
giving a five-membered metallacycle. The Pt(1)-N(1)
2.027(9) and Pt(1)-N(2) 2.027(9) Å bond lengths are equal
within 3σ, and O(1)-N(1) 1.423(11) and O(2)-N(2) 1.436(11)
Å are typical single O-N bonds.29 The N(1)-Pt(1)-N(2)
angle is 83.0(3)°, and this value agrees well with those
previously observed in the related N,N-coordinated five-
membered Pt-chelates of the type [PtCl2L] (see above).
Synthesis and Characterization of {HO(H)N-C∩C)NOH}-
PtII-Type Chelates. The (hydroxylamino∩oxime)PtII chelates
[PtCl2(OHA)] (R ) Me 8, Ph 9) and [Pt(OHA-H)2] (R )
Me 10, Ph 11; Scheme 2), where OHA ) HO(H)-
NCMe2C(R))NOH, and OHA-H ) -O(H)NCMe2C(R))
NOH (Figure 1), have previously been synthesized by
treatment of K2[PtCl4] with HO(H)NCMe2C(Me))NOH (3)
or HO(H)NCMe2C(Ph))NOH (4) in 1:1 (Route 2A, Scheme
2) or 1:4 (Route 2B, Scheme 2) molar ratios, correspond-
ingly, in an ethanol/water solution, but the then obtained
species 8-11 were characterized only by microanalysis and
no other physicochemical data were presented.32 For the
preparation of 8-11 we have now employed a modification
of a method described in ref 32, and our synthetic procedure
is given in the Experimental Section. We also characterized
to [Pt(OHA-H)2] (R ) Me, 10; via Route 2D) (ca. 5% after
2 d). Attempts to perform a similar conversion for 9 did not
result in the formation of [Pt(OHA)2][PtCl4] (R ) Ph) but
affords a mixture of yet unidentified products. Evaporation
of a 6 M HCl solution of 8 in air for 1 d produces 12 (orange-
yellow crystals) in a mixture with unreacted 8 (dark-red
crystals); 8 and 12 were mechanically separated.
In addition to the obtained satisfactory microanalyses,
1
8-12 were characterized by IR and 1D H, 13C{1H}, 195Pt,
1
and 2D H,1H-COSY,1H,13C-HSQC NMR spectroscopies,
and 15 also by X-ray diffraction. The IR spectra of 8-12
display a medium intensity band in the range 1599-1636
cm-1, assigned to the ν(C)N) stretching vibrations of the
coordinated oxime group C)NOH, and medium intensity
bands in the range between 3066 and 3249 cm-1 due to the
ν(N-H) and ν(O-H) stretches. Complexes 8-12 appear to
be sufficiently stable in both DMSO-d6 and DMSO to permit
NMR measurements; the low rate of solvolysis was proved
by repeated measurements of the spectra in 95:5 (v/v) mixture
of DMSO-d6:DMSO; no signals from Pt-bound DMSO33
were observed after 3 h of incubation at 25 °C. The 1H NMR
spectra of 8-12 in DMSO-d6 exhibit two broad singlets in
the range between 9.8 and 13.3 ppm (from the OH protons
of the hydroxylamine and oxime NOH group) and a
resonance in the range of 9.0-9.6 ppm (from the NH
hydroxylamine proton). The 13C{1H} spectra of 8-12
indicate the presence of peaks from the coordinated oxime
C)N moiety; they emerge in the range of 154-168 ppm,
which is usual for the C)N groups.25 The 195Pt NMR spectra
of 8-12 in DMSO-d6 display one peak between -2020 and
-2270 ppm in the typical range for PtII species.26
1
complexes 8-11 by IR, and H, 13C, 195Pt NMR spec-
troscopies.
The monitoring of the filtrate from reactions 2A and 2B
(Scheme 2) using 2D 1H,1H-COSY, and1H,13C-HSQC NMR
correlation experiments indicates that the low yields for the
(hydroxylamino∩oxime)PtII chelates can be explained by, on
one hand, the significant residual solubility of 8-11 and,
on the other hand, the insufficient selectivity of the process,
when the chelate is contaminated with the bis-chelate and
Vice Versa.
In the 195Pt NMR spectrum of 12 measured in DMSO-d6,
one more signal from [PtCl4]2- (-1640 ppm) was detected.
One should mention that typically in aqueous DMSO
solutions the Pt-Cl bond is subject to solvation giving
(DMSO)PtII species.22,33 However, we observed that in
anhydrous DMSO-d6, which is conventionally used for NMR
measurements, the rate of substitution is low and during 3 h
In 6 M HCl solution, 8 partially (ca. 10% after 1 d)
transforms to the previously unreported compound
[Pt(OHA)2][PtCl4] (R ) Me, 12; via Route 2C), and then
(33) Kukushkin, V.Yu.; Belsky, V. K.; Konovalov, V. E.; Kyrakosyan,
G. A.; Konovalov, L. V.; Moiseev, A. I.; Tkachuk, V. M. Inorg. Chim.
Acta 1991, 185, 143.
(32) Stetsenko, A. I.; Naumova, K. P.; Volodarskii, L. B. Zh. Obshch. Khim.
1975, 45, 1787.
Inorganic Chemistry, Vol. 47, No. 15, 2008 6923

Luzyanin et al.
Figure 5. Types of metal complexes with alkylhydroxylamines. In B, DG
denotes a donor group different from the N(H)OH.
indicates the presence of two similar intramolecular hydrogen
bonds between the two chelating species, stabilizing structure
of 12, with the following observed distances and angles:
O(2)-H(2O) 0.95 Å, O(2)-H(2O) · · · O(1) 1.80 Å, and
O(2)-H(2O) · · · O(1) 164.9°. Related intramolecular H-
bondings were also observed in other bis-chelate complexes,
namely, in [Pt{HONC(Me)C(Me)NO}2],27 [Pd{HON(1,2-
C6H4)N)O}2],30 and [Ni{HONC(dO)C(dO)N)O}2].31
Generation of the Dinitrosoalkane Ligand by
Oxidation of (BHA)PtII Complexes. In general, oxidation
of (HONH2)PtII complexes can proceed at the metal, at the
hydroxylamine ligand, or at both centers; some examples of
oxidation of the unsubstituted NH2OH ligands at Pt,36 Mn,37
and Re38 centers to form nitrosyl, nitroxyl, or nitrogen oxides
have been reported.36–38 On the contrary, oxidation of
N-bound alkylhydroxylamines RN(H)OH is substantially less
studied.
Figure 4. Thermal ellipsoid view of 12 with atomic numbering scheme
(hydrogen labels are not shown for simplicity). Thermal ellipsoids are drawn
with 50% probability. Selected bond lengths (Å) and angles (deg):
Pt(1)-N(2) 1.992(2), Pt(1)-N(1) 2.025(2), Pt(2)-Cl(1) 2.3036(8), Pt(2)-Cl(2)
2.2956(8), O(1)-N(1) 1.438(3), O(2)-N(2) 1.376(3), N(2)-Pt(1)-N(1)
101.61(9), N(2)#1-Pt(1)-N(1) 78.39(9), Cl(2)-Pt(2)-Cl(1) 89.77(3). The
symmetry transformation used to generate equivalent atom: #1 ) -x, -y,
-z.
The metal complexes having alkylhydroxylamine ligands
can be divided into three categories (A-C, Figure 5). Group
A is represented by compounds bearing monodentately
N-bound RN(H)OH species. To our knowledge, no examples
of intramolecular oxidation of RN(H)OH in complexes were
reported, although a few cases of the oxidation of that species
upon coordination to metal centers are known.1 However,
the nature of the oxidants in all these examples remains
unknown. Group B exemplifies metal complexes with
bidentate coordination of HO(H)N∩DG species (DG is a
donor group which is different from the N(H)OH moiety,
e.g., an oxime or amine functionality). The reported oxida-
tions of type B compounds include the reaction of
[PdCl2{HO(H)NCMe2C(R))NOH}] with 2,3,5,6-tetrachloro-
p-benzoquinone that gives the nitrosoalkane compound
[PdCl2{O)NCMe2C(R))NOH}] and the oxidation of
[M{HO(H)NCMe2C(R))NOH}2] (M ) Pd, Ni) with the
same reagent, which affords [M{•ONCMe2C(R))NOH}2]
with radical anion ligands.39,40
at 20-25 °C only about 10% of [PtCl4]2- converts to the
known22,33 [PtCl3(DMSO-d6)]- complex (-2980 ppm; ob-
tained in this work).
In the X-ray structure of 12 (Figure 4), the coordination
polyhedra of both metal centers are slightly distorted square
planes. In the cation, two neutral ligands HON(H)-
CMe2C(Me))NOH are coordinated by the hydroxylamino
and the oxime nitrogens thus forming two five-membered
metallacycles with the hydroxylamino N atoms in the mutual
trans-positions. The Pt(1)-N(2) 1.992(2) and Pt(1)-N(1)
2.025(2) Å bond lengths are normal, and O(1)-N(1)
1.438(3), O(2)-N(2) 1.376(3) Å are typical single O-N
bonds.29 The N(2)#1-Pt(1)-N(1) angle is 78.39(9)°, and
this value agrees with those previously observed in related
N,N-coordinated five-membered chelates of the type [PtCl2L],
where L ) bpy [79.1-83.1°],34 phen [80.9-81.5°],34
H2NCH2CH2NH2 [73.2-83.7°],35 and H2NCH2CH2NMe2
[84.0°].35 Inspection of the distances and angles between the
oxime proton (H2O) of one of the chelating ligands and the
hydroxylamine oxygen (O1) of the other one, clearly
Group C is formally represented by metal complexes with
the bidentate R{N(H)OH}2 ligands, having two N(H)OH
moieties. However, only one representative of Group C
(34) (a) Osborn, R. S.; Rogers, D. J. Chem. Soc., Dalton Trans. 1974, 1002.
(b) Textor, M.; Oswald, H. R. Z. Anorg. Allg. Chem. 1974, 407, 244.
(c) Canty, A. J.; Skelton, B. W.; Traill, P. R.; White, A. H. Aust.
J. Chem. 1992, 45, 417. (d) Connick, W. B.; Henling, L. M.; Marsh,
R. E.; Gray, H. B. Inorg. Chem. 1996, 35, 6261. (e) Falvello, L. R.;
Garde, R.; Miqueleiz, E. M.; Tomas, M.; Urriolabeitia, E. P. Inorg.
Chim. Acta 1997, 264, 297. (f) Grzesiak, A. L.; Matzger, A. J. Inorg.
Chem. 2007, 46, 453.
(36) (a) Goremykin, V. I. Bull. Acad. Sci. U.R.S.S., Classe Sci. Chim. 1943,
185. (b) Vorob’ev-Desyatovskii, N. V.; Kukushkin, V.Yu.; Patrabansh,
K. M.; Stefanova, O. V. Zh. Obshch. Khim. 1989, 59, 776. (c)
Vorob’ev-Desyatovskii, N. V.; Lukin, Yu. N.; Kukushkin, V.Yu. Zh.
Obshch. Khim. 1992, 62, 521.
(37) Albertin, G.; Antoniutti, S.; Bravo, J.; Castro, J.; Garc´ıa-Fonta´n, S.;
Mar´ın, M. C.; Noe´, M. Eur. J. Inorg. Chem. 2006, 3451.
(38) Southern, J. S.; Hillhouse, G. L.; Rheingold, A. L. J. Am. Chem. Soc.
1997, 119, 12406.
(35) (a) Browall, K. W.; Kasper, J. S.; Interrante, L. V. Acta Crystallogr.,
Sect. B 1974, 30, 1649. (b) Iball, J.; MacDougall, M.; Scrimgeour, S.
Acta Crystallogr., Sect. B. 1975, 31, 1672. (c) Ellis, L. T.; Hambley,
T. W. Acta Crystallogr., Sect. C. 1994, 50, 1888. (d) Koz’min, P. A.;
Surazhskaya, M. D.; Fedotova, T. N.; Kuznetsova, G. N.; Minacheva,
L.Kh.; Baranovskii, I. B. Zh. Neorg. Khim. 2000, 45, 1146. (e)
Melanson, R.; de la Chevrotiere, C.; Rochon, F. D. Acta Crystallogr.,
Sect. C. 1987, 43, 57.
(39) Larionov, S. V.; Kosareva, L. A.; Boguslavskii, E. G. Russ. Chem.
Bull. 1986, 9, 2110.
(40) Larionov, S. V.; Kirichenko, V. N.; Stetsenko, A. I. V. N.; Naumova,
K. P.; Dyachenko, S. A.; Volodarskii, L. B. Zh. Neorg. Khim. 1983,
28, 411.
6924 Inorganic Chemistry, Vol. 47, No. 15, 2008

Oxidation of Pt-bound Bis-hydroxylamine
Scheme 3
One should mention that although nitrosoalkane complexes
of various metal centers are known,3,4 reported (nitrosoal-
kane)Pt species are still quite rare. Their examples are limited
exclusively to (i) the platinum(0) complexes [Pt(tBuN)
O)2(Ph3P)2], [Pt(CF3N)O)(PPh3)2], and [Pt(PhN)O)(PPh3)2]
obtained via the reaction of the preprepared nitrosoalkanes
with [Pt(C2H4)(PPh3)2] or [Pt(PPh3)3], correspondingly,42 (ii)
the platinum(II) complexes [PtCl2(MeN)O)(bpy)],43
[PtCl2(tBuN)O)L] (L ) various N-donor ligands),43 and
[PtCl2(RN)O)2] (R ) Bu, Ph), obtained by substitution
of chlorides in [PtCl4]2- with the appropriate free nitrosoal-
kane,43,44 and (iii) the chelates [PtX2(O)NCRR′2ONCRR′2)]
(X ) Cl, Br; R/R′ ) alkyls) generated via redox coupling
of coordinated oximes and described by one of us.8,9
44
t
Liberation of the Ligand from the Dinitrosoalkane
Complex. Treatment of 14 with 2 equiv of 1,2-bis(diphe-
nylphosphino)ethane (dppe) in CH2Cl2 at room temperature
results in the formation of 20 (IUPAC name:21 3,3,4,4-
tetramethyl-1,2-diazete-1,2-dioxide) in about 90% yield and
the precipitation of the known trans-[Pt(dppe)2](Cl)2,45
identified by 31P NMR spectroscopy (Scheme 4, Route 1M).
Compound 20 is generated from the liberated dinitrosoalkane
O)NCMe2CMe2NdO upon cyclization giving the new N)N
bond. The known alternative preparation of 20 includes the
mild metal-free oxidation of free bis-hydroxylamine species
1 by bromine in aqueous solution (Route 1N).46
The results of these experiments clearly indicate that (i)
the PtII center provides a stabilizing effect on the elusive
dinitrosoalkane species; (ii) the dinitroso ligand shows a
dramatic stabilizing effect by the metal center in a low
oxidation state (PtII vs PtIV) probably because of the
π-acceptor ability of the former.
complexes was so far described, that is, the nickel(II) bis-
chelate [NiIICl(BHA-H)(BHA)], which upon oxidation by
20
PbO2 gives [NiII{•ONCMe2CMe2NO}2] as a product of the
2e-oxidation/deprotonation of the N(H)OH functionalities.20
In our experiments, the chlorination of the platinum(II)
complex [PtCl2(BHA)] (7) (Scheme 3) furnishes the ni-
trosoalkane ligands and shows a remarkable solvent depen-
dence. Thus, in freshly distilled dry chloroform, a passage
of dry Cl2 leads to the oxidation of one N(H)OH group and
yields the mononitrosoalkane complex [PtCl2{HO(H)N-
CMe2CMe2N)O}] (13), where only one hydroxylamine
moiety of the starting chelate was oxidized to the nitrosoal-
kane group (Route 1H). When the chlorination is performed
in water, both N(H)OH functionalities of the starting complex
are oxidized producing the dinitrosoalkane compound
[PtCl2(O)NCMe2CMe2N)O)] (14; Route 1I). Complex 14
can also be obtained from 13 upon its treatment with Cl2 in
water (Route 1J). The observed reactivity and solvent
dependence is in good agreement with the fact that Cl2 is a
much stronger oxidant in highly polar aqueous media than
in low-polar chloroform.41 Hence, the usage of these two
solvents, in the chlorination, allows the synthesis of two
different nitrosoalkane products from the same starting
material.
Characterization of the Nitroso and Dinitrosoalkane
Complexes Derived from the Oxidation of (BHA)PtII
Complexes. The formulation of complexes 13 and 14 was
supported by satisfactory C, H, and N microanalyses. These
species were also characterized by IR and 1D 1H, 13C{1H},
195Pt, and 2D 1H,1H-COSY,1H,13C-HSQC NMR spec-
troscopies, and X-ray diffraction while complex 15 was
1
identified based on IR and H NMR data.
The IR spectra of 13-15 display one very strong band
each at 1525-1540 cm-1 due to the ν(NdO) from the nitroso
group of the newly formed nitrosoalkane ligands. Moreover,
Furthermore, a prolonged (1 h) chlorination of 7 or 14 in
water at 80-85 °C results in further oxidation, now of the
PtII center, giving the platinum(IV) dihydroxo-dinitroso
complex 15. The latter compound is not stable in both
solution and in the solid state and at room temperature (in
the solid state 50% conversion occurred for 3 h, while in
acetone-d6 solution 95% conversion was observed already
after ca. 5 min) undergoes reductive elimination along with
some side-reactions yielding a mixture of 14 with yet
unidentified products.
(42) (a) Cenini, S.; Porta, F.; Pizzotti, M.; Crotti, C. J. Chem. Soc., Dalton
Trans. 1985, 1, 163. (b) Jones, C. J.; McCleverty, J. A.; Rothin, A. S.
J. Chem. Soc., Dalton Trans. 1985, 2, 401. (c) Pizzotti, M.; Porta, F.;
Cenini, S.; Demartin, F.; Masciocchi, N. J. Organomet. Chem. 1987,
330, 265.
(43) (a) Mansuy, D.; Dreme, M.; Chottard, J. C.; Guilhem, J. J. Organomet.
Chem. 1978, 161, 207. (b) Mansuy, D.; Dreme, M.; Chottard, J. C.;
Girault, J. P.; Guilhem, J. J. Am. Chem. Soc. 1980, 102, 844.
(44) (a) Fanizzi, F. P.; Maresca, L.; Natile, G.; Lanfranchi, M.; Tiripicchio,
A.; Pacchioni, G. J. Chem. Soc., Chem. Commun. 1992, 4, 333. (b)
Clark, R. J. H.; Fanizzi, F. P.; Natile, G.; Pacifico, C.; van Rooyen,
C. G.; Tocher, D. A. Inorg. Chim. Acta 1995, 235, 205. (c) Putsykin,
Yu. G.; Volodarskii, L. B. IzV. Sib. Otd. Akad. Nauk SSSR, Ser. Khim.
Nauk. 1968, 4, 101.
(41) Becker, H. G. O.; Berger, W.; Domschke, G.; Fangha¨nel, E. et al.
Organikum - Qu´ımica Orgaˆnica Experimental, 2ed.; Rauter, A. P.,
Herold, B. J., translation, Eds.; Fundac¸a˜o Calouste Gulbenkian: Lisboa,
1997; p 1064.
(45) (a) Appleton, T. G.; Bennett, M. A.; Tomkins, I. B. Chem. Soc., Dalton
Trans. 1976, 439. (b) Lindner, E.; Fawzi, R.; Mayer, H. A.; Eichele,
K.; Hiller, W. Organometallics 1992, 11, 1033.
(46) Ullman, E. F.; Singh, P. J. Am. Chem. Soc. 1972, 94, 5077.
Inorganic Chemistry, Vol. 47, No. 15, 2008 6925

Luzyanin et al.
Scheme 4
compound 13 exhibits two strong bands in the 3220-2990
cm-1 range due to the ν(N-H) and ν(O-H) stretching
vibrations of the hydroxylamine moieties.
Complex 14, as the others, shows a slightly distorted
square coordination, with the bidentate dinitroso
O)NCMe2CMe2N)O ligand coordinated by both N-atoms,
forming a five-membered chelating ring [N(1)Pt(1)-N(2)
82.7(3)°], similar to those observed in the two related metal
dinitrosoalkane complexes.5,6 The measured NdO bond
distances at the nitroso fragments are equal within 3σ
[O(1)-N(1) 1.205(8); O(2)-N(2) 1.202(8) Å] and these
values agree with those for the Pt-nitrosoalkane complexes
trans-[PtCl2(tBuN)O)2] (1.21(1) Å),44 and [PtCl2(R2CN-
OR2CN)O)] (R ) Me, C5H10) (1.21-1.24 Å).8,9
1
The H NMR spectrum of 13 in DMSO-d6 displays two
broad singlets from the NH and OH protons of the hydroxy-
lamine N(H)OH moieties resonating at 7.6 and 10.3 ppm,
correspondingly. In the 13C{1H} NMR spectra of 13 and 14
in DMSO-d6, the CN carbons resonate at about 80 and 110
ppm, within the expected25 range. The 195Pt NMR spectra
of 13 and 14 in DMSO-d6 display one signal at about -2000
ppm, characteristic of PtII species.26
The structures of the nitroso complexes 13 and 14 have
been determined by X-ray diffraction (Figures 6 and 7). We
also determined the X-ray structure of 10 but the crystals
were of insufficient quality probably because of the decom-
position of this PtIV complex.
Generation of Nitrosoalkane Ligands by Oxidation
of (OHA)PtII Complexes. We found that the complexes
[PtCl2{HO(H)NC(Me)2C(R))NOH}] (8, 9) upon treatment
with Cl2 in CHCl3 were easily oxidized to the nitrosoalkane
compounds [PtCl2{O)NCMe2C(R))NOH}] (R ) Me 16,
Ph 17) (Scheme 5, Route 2E), respectively, while the
corresponding chlorination of the bis-chelates [Pt{HO-
(H)NCMe2C(R))NO}2] (10, 11) gives [Pt{O)NCMe2-
C(R))NO}2] (R ) Me 18, Ph 19).
In case of 8, the oxidation to 16 can also be performed
using 30% aqueous H2O2 taken in a 10-fold excess while 9
is more stable toward oxidation than 8 and under similar
conditions remains intact. In compounds 16-19, the ni-
trosoalkane group originates from the 2e-oxidation of the
hydroxylamino group HO(H)N. It is worthwhile mentioning
that despite the oxidative deoximation of “HON)C”-type
ligands is well-known,8,9 the PtII center provides such a
strong protection of the oxime group of the OHA ligands
that it stays unreacted under the drastic reaction conditions.
It is worth mentioning that physicochemical data provided
in the next section support the dinitroso structure of 18 and
Complex 13 provides the first crystallographic evidence
for a metal complex with the newly formed hybrid nitroso-
hydroxylamino O)NCMe2CMe2N(H)OH ligand. In 13, the
coordination polyhedron of the metal center is a slightly
distorted square, while the bidentate O)NCMe2CMe2-
N(H)OH ligand is coordinated by both hydroxylamino and
nitroso nitrogens, forming a five-membered chelate ring
similar to those observed in related Pt-chelates of the type
[PtCl2(NN)].34,35 In the ligand, the O(1)-N(1) (1.407(4) Å)
bond length has a typical value for a single O-N bond while
the measured O(2)-N(2) distance of the nitroso fragment is
1.207(3) Å. The latter value is normal for a O)N double
bond, and agrees with those for the relevant Pt-nitrosoalkane
complexes, that is, trans-[PtCl2(tBuN)O)2] (1.21(1) Å),44
and [PtCl2(R2CNOR2CN)O)] (R ) Me, C5H10) (1.21-1.24
Å).8,9
Figure 6. Thermal ellipsoid view of 13 with atomic numbering scheme.
Thermal ellipsoids are drawn with 50% probability. Selected bond lengths
(Å) and angles (deg): Pt(1)-N(1) 2.033(3), Pt(1)-N(2) 1.924(3), Pt(1)-Cl(1)
2.2965(8), Pt(1)-Cl(2) 2.2953(8), O(1)-N(1) 1.407(4), O(2)-N(2) 1.207(3),
N(1)-Pt(1)-N(2) 83.00(11).
Figure 7. Thermal ellipsoid view of 14 with atomic numbering scheme.
Thermal ellipsoids are drawn with 50% probability. Selected bond lengths
(Å) and angles (deg): Pt(1)-N(1) 1.944(6), Pt(1)-N(2) 1.946(7), Pt(1)-Cl(1)
2.2859(18), Pt(1)-Cl(2) 2.2817(18), O(1)-N(1) 1.205(8), O(2)-N(2)
1.202(8), N(1)-Pt(1)-N(2) 82.7(3).
6926 Inorganic Chemistry, Vol. 47, No. 15, 2008

Oxidation of Pt-bound Bis-hydroxylamine
Scheme 5
nitroso functionality (Scheme 3). However, the corresponding
process in water results in the oxidation of both hydroxy-
lamino moieties and affords a (dinitrosoalkane)Pt complex
(Scheme 3).
The liberation of the ligated dinitrosoalkane can be
achieved by treatment of the complex with a diphosphine
(dppe), and the free dinitroso compound is unstable and
undergoes a fast cyclization giving the cyclic R-dinitrone
3,3,4,4-tetramethyl-1,2-diazete-1,2-dioxide (Scheme 4). The
oxidation of (hydroxylamino∩oxime)PtII complexes occurs
selectively at the hydroxylamino group affording a series of
(nitroso∩oxime)PtII species, where the oxime group remains
intact (Scheme 5). Further studies directed toward widening
the family of metal dinitrosoalkanes by oxidation of bis-
hydroxylamino ligands bound to various metal centers are
underway in our group.
19. However, the radical ion structure [Pt{•ONC-
Me2C(R))NOH}2], which is similar to the previously
reported radical ions [M{•ONCMe2C(R))NO}2] (M ) Pd,39
Ni40), cannot be ruled out. However, to distinguish between
the nitroso and the radical structures of 18 and 19 further
data, for example, X-ray structure determinations, would be
needed to obtain quantitative information on the NO bond
orders in NdO vs · N-O groups.
Characterization of the Nitrosoalkane Complexes
Derived from the Oxidation of (OHA)PtII Complexes. The
formulation of all complexes 16-19 was supported by
satisfactory C, H, and N microanalyses. They were also
characterized by IR and 1D 1H, 13C{1H}, 195Pt, and 2D 1H,1H-
COSY,1H,13C-HSQC NMR spectroscopies. Compound 16
was recently synthesized by us via a different route10 and
the authenticity of our samples with those described previ-
ously10 was confirmed by elemental analyses, IR, and X-ray
single-crystal study.
Experimental Section
Materials and Instrumentation. The compounds K[PtCl3-
(Me2SO)],22 cis-[PtCl2(Me2SO)2],22 1,14 2,14 and 3·MeCO2H,47 and
447 were synthesized in accord with the published procedures.
Solvents were obtained from commercial sources and used as
received while chloroform was dried using standard methods.41 C,
H, and N elemental analyses were carried out by the Microanalytical
Service of the Instituto Superior Te´cnico. IR spectra (4000-400
cm-1) were recorded on a BIO-RAD FTS 3000MX instrument in
KBr pellets. 1D (1H, 13C{1H}, 195Pt) NMR experiments and 2D
(1H,1H-COSY, and1H,13C-HSQC) NMR correlation spectra were
recorded on Bruker Avance II+ 300 and 400 MHz (UltraShield
Magnet) and Varian UNITY 300 spectrometers at ambient tem-
perature. 195Pt NMR chemical shifts are given relatively to K2[PtCl6]
(0.0 ppm); half-width is given in parentheses.
X-ray Structure Determinations. The crystals were immersed
in cryo-oil, mounted in a Nylon loop and measured at a temperature
of 120 K. The X-ray diffraction data were collected by means of
a Nonius KappaCCD diffractometer using Mo KR radiation (λ )
0.71073 Å). The Denzo-Scalepack48 or EvalCCD49 program
packages were used for cell refinements and data reductions. All
of the structures were solved by direct methods using the SHELXS-
97,50 SIR97,51 SIR2002,52 or SIR2004,53 with the WinGX54
graphical user interface. An empirical absorption correction was
The IR spectra of 16-19 display medium intensity bands
in the range 1599-1636 cm-1 assigned to ν(C)N) stretching
vibrations of the coordinated oxime group. The absence of
the ν(O-H) stretches of the hydroxylamine moieties is
logical for the deprotonated oxime group. The very strong
band at 1547-1557 cm-1 is assigned to the ν(NdO) of the
newly formed nitroso ligands.
1
The H NMR spectra of 16 and 17 in DMSO-d6 show
one broad singlet at about 12.0 ppm (from the NOH protons
of the oxime group). The 13C{1H} NMR spectra of 16-19
in DMSO-d6 display the signal from the coordinated oxime
C)N moiety at about 170 ppm, which is typical for a C)N
groups.25 The 195Pt NMR spectra of 16-19 in DMSO-d6
exhibit one resonance in the normal range for PtII species.26
(47) (a) Volodarskii, L. B.; Koptyug, V. A.; Lysak, A. N. Zh. Organ. Khim.
1966, 2, 114; Chem. Abstr. 1966, 64, 14139h. (b) Putsykin, Y.U. G.;
Volodarskii, L. B. IzV. Sib. Otd. Akad. Nauk SSSR, Ser. Khim. Nauk.
1968, 4, 101; Chem. Abstr. 1969, 70, 46764a. (c) Dayagi, S.; Degani,
Y. In The Chemistry of the Carbon-Nitrogen Double Bond; Patai, S.,
Ed.; Interscience: London, 1970; p 111.
(48) Otwinowski Z.; Minor, W. Processing of X-ray Diffraction Data
Collected in Oscillation Mode. Methods in Enzymology, Macromo-
lecular Crystallography, part A; Carter, C. W., Jr., Sweet, R. M., Eds.;
Academic Press: New York, 1997; Vol. 276, pp 307-326.
(49) Duisenberg, A. J. M.; Kroon-Batenburg, L. M. J.; Schreurs, A. M. M.
J. Appl. Crystallogr. 2003, 36, 220.
Final Remarks
We report here on a novel synthetic route to the almost
unexplored dinitrosoalkane species, which consists on the
oxidation of the easy-to-obtain platinum complexes with the
bis-hydroxylamine ligand. Chlorine appears to be a suitable
oxidizing agent, and the extent of oxidation can be controlled
by a proper choice of solvent. In fact, the chlorination of
(bis-hydroxylamine)PtII complex shows a remarkable solvent
dependence and produces, in freshly distilled dry chloroform,
a Pt-mononitrosoalkane complex in which only one hy-
droxylamine group has been selectively oxidized to the
(50) Sheldrick, G. M. SHELXS-97, Program for Crystal Structure Deter-
mination; University of Go¨ttingen: Go¨ttingen, Germany, 1997.
(51) Altomare, A.; Burla, M. C.; Camalli, M. C.; Giacovazzo, C.;
Guagliardi, A.; Moliterni, A. G. G.; Polidori, G.; Spagna, R. J. Appl.
Crystallogr. 1999, 32, 115.
(52) Burla, M. C.; Camalli, M.; Carrozzini, B.; Cascarano, G. L.; Giaco-
vazzo, C.; Polidori, G.; Spagna, R. J. Appl. Crystallogr. 2003, 36,
1103.
(53) Burla, M. C.; Camalli, M.; Carrozzini, B.; Cascarano, G. L.; Giaco-
vazzo, C.; Polidori, G.; Spagna, R. J. Appl. Crystallogr. 2005, 38,
381.
(54) Farrugia, L. J. J. Appl. Crystallogr. 1999, 32, 837.
Inorganic Chemistry, Vol. 47, No. 15, 2008 6927

Luzyanin et al.
Table 1. Crystal Data
5
7
12
13
14
empirical formula
fw
temp (K)
λ(Å)
cryst syst
space group
a (Å)
b (Å)
c (Å)
R (deg)
ꢀ (deg)
γ (deg)
V (Å3)
C12H36Cl4N4O6Pt2
864.43
120(2)
0.71073
monoclinic
C2/c
16.1477(10)
13.0342(9)
11.6516(6)
90
107.967(4)
90
2332.7(2)
4
2.461
12.474
7365
C6H16Cl2N2O2Pt
414.20
120(2)
0.71073
monoclinic
P21/n
9.3515(9)
8.9988(9)
13.9799(13)
90
106.604(5)
90
1127.4(2)
4
2.440
12.893
11285
C10H28Cl4N4O6Pt2
832.34
120(2)
C6H14Cl2N2O2Pt
412.18
120(2)
0.71073
monoclinic
P21/n
9.3692(8)
17.694(2)
13.4721(16)
90
99.641(8)
90
2201.8(4)
8
2.487
13.203
30127
C6H12Cl2N2O2Pt
410.17
120(2)
0.71073
monoclinic
P21/c
12.3005(3)
16.7021(6)
10.8385(4)
90
94.883(2)
90
2218.63(13)
8
2.456
13.102
0.71073
triclinic
j
P1
7.3585(5)
8.5897(5)
9.6385(4)
104.471(4)
104.070(5)
98.437(5)
558.06(6)
1
Z
Fcalc (Mg/m3)
2.477
13.030
10323
µ(Mo KR) (mm-1
no. reflns.
)
39701
Unique reflns.
Rint.
2679
2431
2812
0.0285
0.0167
0.0374
5018
4362
0.0544
0.0299
0.0576
0.0220
0.0270
0.0608
2
0.0751
0.0434
0.1087
2
0.0344
0.0194
0.0304
R1a (I g 2σ)
wR2b (I g 2σ)
a R1 ) Σ|Fo| - |Fc|/Σ|Fo|. b wR2 ) [Σ[w(Fo - Fc )2]/ Σ[w(Fo )2]]1/2
.
2
applied to all of the data (SADABS,55 XPREP in SHELXTL56).
Structural refinements were carried out using SHELXL-97.57 The
OH, H2O hydrogen atoms, and NH hydrogens (except NH atoms
in 7 and 12) were located from the difference Fourier map but not
refined. The coordinates were either fixed or the hydrogen atoms
were constrained to ride on their parent atom with Uiso ) 1.5Ueq
(parent atom). All other hydrogen atoms (including the NH
hydrogen atom in 7 and 12) were positioned geometrically and
constrained to ride on their parent atoms, with C-H ) 0.98 Å,
NH ) 0.93 Å, and Uiso ) 1.5Ueq (parent atom). The crystallographic
details are summarized in Table 1. Selected bond lengths and angles
are given in figure captions.
Synthetic Work. [Pt{HO(H)NCMe2CMe2N(H)OH}2][PtCl4]·
H2O (5). A solution of 2 (0.049 g, 0.2 mmol) in water (1 mL) was
added to a solution of K2[PtCl4] (0.042 g, 0.1 mmol) in water (5
mL). The reaction mixture was heated at 80 °C for about 1 d and
then left to stand in air for 5 d at 20-25 °C. During this time the
solvent was evaporated to about 1/2, followed by a precipitation of
a mixture of 5 (red crystals suitable for X-ray diffraction) and a
colorless solid. The crystals of 5 were mechanically separated from
the mixture, washed with two 5 mL portions of cold (10 °C) water
and dried in air at 20-25 °C. Monitoring of the colorless residue
and the filtrate by IR and NMR allows the identification of 5-7 in
a mixture with KCl; these components were not separated because
of their similar and high water solubilities. Yield of 5 is 0.039 g,
37%, based on Pt. Anal. Calcd for C12H34N4Cl4O5Pt2: C, 17.03; H,
4.05; N, 6.62%. Found: C, 17.21; H, 3.70; N, 6.50%. IR spectrum
(selected bands), cm-1: 3230 and 2995 mw ν(O-H) and ν(N-H).
1H NMR (D2O, δ): 1.25 (m, 12H, NCMe2). 13C{1H} NMR (DMSO-
d6, δ): 17.6, 19.5 (Me), 72.0 (CMe2). 195Pt NMR (D2O, δ): -1713
(120 Hz; [PtCl4]2-) and -2464 (380 Hz; [Pt(BHA)2]2+). Crystals
suitable for X-ray study were obtained directly from the reaction
mixture.
crystals were separated by filtration and washed with two 5 mL
portions of cold (10 °C) water and dried in air at room temperature.
An additional amount of 7 (0.010 g) can be obtained by evaporation
1
of the filtrate in air up to about /4 of the initial volume. The total
yield is 0.038 g, 45%. Anal. Calcd for C6H16N2Cl2O2Pt: C, 17.40;
H, 3.89; N, 6.76%. Found: C, 17.30; H, 3.92; N, 6.70%. IR spectrum
1
(selected bands), cm-1: 3228 mw ν(O-H), 2918 m ν(N-H). H
NMR (DMSO-d6, δ): 1.16, 1.23, 1.25, 1.27 (s, 12H, NCMe2), 7.66
(s, br, 2H, NHOH), 9.45 (s, br, 2H, NHOH). 13C{1H} NMR
(DMSO-d6, δ): 22.5, 22.7, 23.8, 24.5 (Me), 77.0 (CMe2). 195Pt NMR
(DMSO-d6, δ): -2492 (340 Hz).
Reaction of 1 equiv Hydroxylamino∩oximes (3 ·MeCO2H
and 4) with K2[PtCl4]. A suspension of hydroxylamino∩oximes
3·MeCO2H or 4 (0.96 mmol) in 40% (v/v) ethanol-water solution
(1.5 mL) was added to a solution of K2[PtCl4] (0.40 g, 0.96 mmol)
in water (2 mL), and the reaction mixture was stirred at 80 °C for
about 30 min resulting in the release of a pale-beige precipitate.
Then, aqueous HCl (6 M, 1.6 mL) was added to the reaction
1
mixture, and the latter was evaporated to about /2 of the initial
volume. The precipitate formed was filtered off, and washed with
one 5 mL portion of water, one 1.5 mL portion of EtOH, and two
2 mL portions of Et2O. Yields are 100 mg, 25% (R ) Me 8); 120
mg, 26% (R ) Ph 9). In the case of 3, when the reaction mixture
after addition of HCl was left to stand for 1 d, a mixture of dark-
red (8) and orange-yellow (12) crystals was formed and filtered
off. Crystals of two types were mechanically separated, and they
were characterized by IR, 1H NMR spectroscopies, and X-ray
diffraction.
[PtCl2{HO(H)NCMe2C(Me))NOH}] (8). Anal. Calcd for
C5H12N2Cl2O2Pt: C, 15.08; H, 3.04; N, 7.04%. Found: C, 15.02;
H, 3.28; N, 6.59%. IR (KBr, selected bands, cm-1): 3199 w and
3090 mw ν(N-H and/or O-H); 1621 m ν(C)N). 1H NMR
(DMSO-d6, δ): 10.45 and 9.88 (s, br, 2H, NOH and NHOH), 9.45
(s, br, 1H, NH), 1.84 (s, 3H), 1.53 (s, 3H), 1.39 (s, 3H) (Me).
13C{1H} NMR (DMSO-d6, δ): 159.1 (C)N), 72.3 (CMe2), 24.4,
21.1, 12.1 (Me). 195Pt NMR (DMSO-d6, δ): -2267 (420 Hz).
[Pt{HO(H)NCMe2C(Me))NOH}2][PtCl4] (12). IR (KBr, se-
lected bands, cm-1): 3227 mw and 3087 ms ν(N-H and/or O-H);
[PtCl2{HO(H)NCMe2CMe2N(H)OH}] (7). The solutions of 2
(0.049 g, 0.2 mmol) in water (1 mL) and K[PtCl3(Me2SO)] (0.084
g, 0.1 mmol) in water (1 mL) were mixed and left to stand in a
closed vial at room temperature for 1d. The released pale yellow
(55) Sheldrick, G. M. SADABS - Bruker Nonius scaling and absorption
correction, v 2.10; Bruker AXS, Inc.: Madison, WI, 2003.
(56) Sheldrick, G. M. SHELXTL , v. 6.14-1; Bruker AXS, Inc.: Madison,
WI, 2005.
1
2969 w and 2929 w ν(C-H from CH3); 1623 mw ν(C)N). H
NMR (DMSO-d6, δ): 10.48 and 9.92 (s, br, 2H, NOH and NHOH),
9.52 (s, br, 1H, NH), 1.78 (s, 6H), 1.53 (s, 6H), 1.40 (s, 6H) (Me).
6928 Inorganic Chemistry, Vol. 47, No. 15, 2008

Oxidation of Pt-bound Bis-hydroxylamine
13C{1H} NMR (DMSO-d6, δ): 165.1 (C)N), 74.9 (CMe2), 22.4,
20.5, 13.1 (Me). 195Pt NMR (DMSO-d6, δ): -2110 (220 Hz) and
-1641(150 Hz).
13), correspondingly. Anal. Calcd for C6H12N2Cl2O2Pt: C, 17.57;
H, 2.95; N, 6.83%. Found: C, 17.34; H, 2.90; N, 6.91%. IR spectrum
1
(selected bands), cm-1: 3216 mw ν(O-H), 1538 vs ν(NdO). H
NMR (DMSO-d6, δ): 1.39 (s, 12H, NCMe2). 13C{1H} NMR
(DMSO-d6, δ): 107.7 (CMe2), 21.6 (Me). 195Pt NMR (DMSO-d6,
δ): -2008 (360 Hz).
[PtCl2{HO(H)NCMe2C(Ph))NOH}]·1/2H2O (9). Anal. Calcd
for C10H15N2Cl2O2.5Pt: C, 25.60; H, 3.22; N, 5.97%. Found: C,
25.02; H, 3.15; N, 6.12%. IR (KBr, selected bands, cm-1): 3249
mw ν(N-H and/or O-H); 3111 mw ν(N-H and/or O-H and/or
C-H from Ph); 2989 w, 2937 w and 2816 w ν(C-H from CH3);
Further Conversions of 8-11 upon Treatment with Excess
Cl2. A suspension of any of the complexes 8-11 (0.07 mmol) in
CHCl3 (9 mL) was chlorinated by a slow passage of dry Cl2 through
the reaction mixture for about 5 min. In the case of 8 and 9, the
starting bright-orange suspension gave a dark-red solution, which
upon evaporation of the solvent gave a dark-crimson solid residue
of 16 and 17, correspondingly. The treatment of 10 with Cl2 leads
to the formation of a crimson precipitate of 18 during the
chlorination while in the case of 11 the color of the released
precipitate 19 is brown-beige. All the obtained products were filtered
off, washed with two 3 mL portions of CHCl3 and dried at 20-25
°C under vacuum. Yields are 16 mg, 59% (16); 6 mg, 18% (17);
31 mg, 96% (18); 26 mg, 65% (19).
1
750 and 705 s δ(C-H from Ph). H NMR (DMSO-d6, δ): 10.53
(s, br, 1H, NOH) and 10.00 (s, br, 1H, NHOH), 9.55 (s, br, 1H,
NH), 7.52-7.48 (m, 3H), 7.36-7.34 (s, 2H) (Ph’s), 1.79 (s, 3H),
1.19 (s, 3H) (Me). 13C{1H} NMR (DMSO-d6, δ): 167.8 (C)N),
130.7, 130.3, 128.9, 128.7, 128,5, 127.7, 127.1 (carbons in Ph),
77.6 (CMe2), 24.7, 21.3 (Me).195Pt NMR (DMSO-d6, δ): -2269
(520 Hz).
Reaction of 4 equiv Hydroxylamino∩oximes (3 ·MeCO2H
and 4) with K2[PtCl4]. A suspension of the hydroxylamino∩oxime
3·MeCO2H or 4 (2.89 mmol) in 40% ethanol-water mixture (3
mL) was added to a solution of K2[PtCl4] (0.30 g, 0.72 mmol) in
water (2 mL) and then heated (80 °C) with stirring for 1.5 h. The
pink precipitate released was separated by filtration, washed with
two 5 mL portions of water, one 2 mL portion of EtOH, and two
2 mL portions of Et2O. Yields are 175 mg, 53% (R ) Me 10); 210
mg, 50% (R ) Ph 11).
[PtCl2{O)NCMe2C(Me))NOH}] (16). Anal. Calcd for
C5H10N2Cl2O2Pt: C, 15.16; H, 2.54; N, 7.07%. Found: C, 15.00;
H, 2.44; N, 7.20%. IR (KBr, selected bands, cm-1): 3210 mw
ν(O-H); 2999 w, 2932 w and 2860 w ν(C-H from CH3); 1637 w
1
ν(C)N); 1555 vs ν(NdO). H NMR (DMSO-d6, δ): 12.12 (s, br,
[Pt{HO(H)NCMe2C(Me))NO}2] (10). Anal. Calcd for
C10H22N4O4Pt: C, 26.26; H, 4.85; N, 12.25%. Found: C, 25.98; H,
4.80; N, 12.01%. IR (KBr, selected bands, cm-1): 3242 w and 3066
mw ν(N-H and/or O-H); 2979 w, 2919 w, and 2827 mw ν(C-H
1H, NOH), 2.04 (s, 3H, Me), 1.49 (s, 6H, CMe2). 13C{1H} NMR
(DMSO-d6, δ): 167.8 (C)N), 107.8 (CMe2), 21.3, 13.4 (Me). 195Pt
NMR (DMSO-d6, δ): -2118 (190 Hz).
[PtCl2{O)NMe2C(Ph))NOH}] (17). Anal. Calcd for
C10H12N2Cl2O2Pt: C, 26.21; H, 2.64; N, 6.11%. Found: C, 26.15;
H, 2.52; N, 6.00%. IR (KBr, selected bands, cm-1): 3233 w
ν(O-H); 3059 w ν(C-H from Ph); 2994 mw, 2936 w and 2864 w
ν(C-H from CH3); 1599 ms ν(C)N and/or CdC from Ph); 1544
1
from CH3); 1632 m ν(C)N). H NMR (DMSO-d6, δ): 13.23 (s,
br, 2H, NHOH), 9.04 (s, 2H, NH), 1.77 (s, 6H), 1.50 (s, 6H), 1.36
(s, 6H) (Me). 13C{1H} NMR (DMSO-d6, δ): 154.1 (C)N), 73.0
(CMe2), 24.4, 21.1, 10.5 (Me). 195Pt NMR (DMSO-d6, δ): -2022
(140 Hz).
1
vs ν(NdO); 755 and 715 s δ(C-H from Ph). H NMR (DMSO-
[Pt{HO(H)NCMe2C(Ph))NO}2] (11). Anal. Calcd for
C20H26N4O4Pt: C, 41.31; H, 4.51; N, 9.64%. Found: C, 41.61; H,
4.52; N, 9.70%. IR spectrum (selected bands), cm-1: 3130 mw
ν(N-H and/or O-H); 3054 w ν(C-H from Ph); 2986 mw, 2934 w,
2865 w and 2822 mw ν(C-H from CH3); 1636 m ν(C)N and/or
CdC from Ph); 750 and 700 s δ(C-H from Ph). 1H NMR (DMSO-
d6, δ): 13.09 (s, br, 2H, NHOH), 9.39 (s, 2H, NH), 7.45-7.38 (m,
6H), 7.34 (d, 2H), 7.32 (t, 2H) (Ph’s), 1.81 (s, 6H), 1.21 (s, 6H)
(Me). 13C{1H} NMR (DMSO-d6, δ): 158.8 (C)N), 132.2, 129.0,
128.7 (carbons from Ph), 73.6 (CMe2), 26.16, 22.67 (Me).195Pt
NMR (DMSO-d6, δ): -2028 (280 Hz).
d6, δ): 12.04 (s, br, 1H, NOH), 7.60–7.57 (m, 3H), 7.53-7.51 (m,
2H) (Ph’s), 1.47 (Me). 13C{1H} NMR (DMSO-d6, δ): 130.7, 128.9,
127.4 (carbons from Ph), 108.9 (CMe2), 22.8 (Me). 195Pt NMR
(DMSO-d6, δ): -2018 (200 Hz).
[Pt{O)NCMe2C(Me)NO}2]
(18).
Anal.
Calcd
for
C10H18N4O4Pt: C, 26.49; H, 4.00; N, 12.36%. Found: C, 25.92; H,
4.02; N, 12.32%. IR (KBr, selected bands, cm-1): 2996 w, 2937 w
and 2863 (w), ν(C-H from CH3); 1624 m ν(C)N); 1557 vs
ν(NdO). 1H NMR (DMSO-d6, δ): 2.30 (s, 6H, Me), 1.48 (s, 12H,
CMe2). 13C{1H} NMR (DMSO-d6, δ): 169.2 (C)N), 108.9 (CMe2),
22.0, 13.0 (Me). 195Pt NMR (DMSO-d6, δ): -2436 (190 Hz).
[Pt{O)NCMe2C(Ph)NO}2] (19). Anal. Calcd for C20H22N4O4Pt:
C, 41.60; H, 3.84; N, 9.70%. Found: C, 40.52; H, 3.62; N, 8.98%.
IR (KBr, selected bands, cm-1): 3065 w ν(C-H from Ph); 2979
mw, 2930 w and 2869 w ν(C-H from CH3); 1638 w ν(C)N and/
or CdC from Ph); 1553 vs ν(NdO); 754 and 714 s δ(C-H from
Generation of Nitrosoalkane and Dinitrosoalkane Species
upon Treatment of
7 with Excess Cl2. [PtCl2{HO(H)-
NCMe2CMe2NO}] (13). Gaseous Cl2 was passed through a
suspension of 7 (0.041 g, 0.1 mmol) in CHCl3 (10 mL) for 5 min.
During the chlorination the color of the precipitate changed from
pale yellow to dark red. The obtained red crystalline solid was
filtered off, washed with two 5 mL portions of CHCl3, and dried
in air at room temperature. Yield is 0.033 g, 80%. Anal. Calcd for
C6H14N2Cl2O2Pt: C, 17.48; H, 3.42; N, 6.80%. Found: C, 17.56;
H, 3.67; N, 6.62%. IR spectrum (selected bands), cm-1: 3238 mw
1
Ph). H NMR (DMSO-d6, δ): 7.59-7.57 (m, 5H), 7.53-7.50 (m,
5H) (Ph’s), 1.46 (s, 12H, Me). 13C{1H} NMR (DMSO-d6, δ): 131.1,
129.3, 128.2, 127.8 (carbons from Ph), 109.3 (CMe2), 23.2 (Me).
195Pt NMR (DMSO-d6, δ): -2409 (220 Hz).
1
ν(O-H), 1527 vs ν(NdO). H NMR (DMSO-d6, δ): 10.28 (s, br,
1H, NHOH), 7.55 (s, br, 1H, NHOH), 1.68, 1.77 (s, 12H, NCMe2).
13C{1H} NMR (DMSO-d6, δ): 22.5, 22.7, 23.8, 24.5 (Me), 80.2
and 102.8 (CMe2). 195Pt NMR (DMSO-d6, δ): -2003 (420 Hz).
[PtCl2{ONCMe2CMe2NO}] (14). Gaseous Cl2 was passed
through a suspension of 7 or 13 (0.1 mmol) in water (10 mL) for
30 or 15 min, respectively. In both cases, the released red compound
was filtered off, washed with two 5 mL portions of CHCl3, and
dried in air. Yield is 0.034 g, 83% (for 7) or 0.032 g, 79% (for
Acknowledgment. This work has been partially supported
by the Fundac¸a˜o para a Cieˆncia e a Tecnologia (FCT),
Portugal, and its POCI 2010 program (FEDER funded).
P.V.G. thanks Group V of Centro de Qu´ımica Estrutural for
an Initiation Research Grant, K.V.L. expresses his gratitude
to FCT and the POCI program (FEDER funded), Portugal,
for a fellowship (Grant SFRH/BPD/27094/2006), and V.Y.K.
Inorganic Chemistry, Vol. 47, No. 15, 2008 6929

Luzyanin et al.
Supporting Information Available: This material is available
free of charge via the Internet at http://pubs.acs.org.
is grateful to the FCT (Cientista Convidado/Professor at the
Instituto Superior Te´cnico, Portugal). This work has also been
supported by the Russian Fund for Basic Research (Grant
08-03-00247) and the Academy of Finland (Grant 110465).
The authors thank Mrs. Julia Golenetskaya for experimental
assistance.
IC800481A
(57) Sheldrick, G. M. SHELXL-97, Program for Crystal Structure Refine-
ment; University of Go¨ttingen: Go¨ttingen, Germany, 1997
.
6930 Inorganic Chemistry, Vol. 47, No. 15, 2008