Azo complexes of osmium(II): Preparation and reactivity of organic azide and hydrazine derivatives

Article abstract of DOI:10.1021/ic302483e

Mixed-ligand hydride complexes OsHCl(CO)(PPh₃)₂L (2) [L = P(OMe)₃, P(OEt)₃] were prepared by allowing OsHCl(CO)(PPh₃)₃ (1) to react with an excess of phosphite P(OR)₃ in refluxin

Full text of DOI:10.1021/ic302483e

Article
pubs.acs.org/IC
Azo Complexes of Osmium(II): Preparation and Reactivity of Organic
Azide and Hydrazine Derivatives
Gabriele Albertin,*,† Stefano Antoniutti,† Laura Bonaldo,† Alessandra Botter,† and Jesus Castro‡
́
†Dipartimento di Scienze Molecolari e Nanosistemi, Universita
̀
Ca’ Foscari Venezia, Dorsoduro 2137, 30123 Venezia, Italy
‡Departamento de Química Inorgan
́
ica, Universidade de Vigo, Facultade de Química, Edificio de Ciencias Experimentais, 36310 Vigo
(Galicia), Spain
S
* Supporting Information
ABSTRACT: Mixed-ligand hydride complexes OsHCl(CO)-
(PPh3)2L (2) [L = P(OMe)3, P(OEt)3] were prepared by
allowing OsHCl(CO)(PPh3)3 (1) to react with an excess of
phosphite P(OR)3 in refluxing toluene. Dichloro compounds
OsCl2(CO)(PPh3)2L (3, 4) were also prepared by reacting 1,
2 with HCl. Treatment of hydrides OsHCl(CO)(PPh3)2L (2),
first with triflic acid and then with an excess of RN3 afforded
organic azide complexes [OsCl(η1-N3R)(CO)(PPh3)2L]BPh4
(5−7) [R = 4-CH3C6H4CH2, C6H5CH2, C6H5; L = P(OEt)3].
Benzylazide complexes react in CH2Cl2/ethanol solution, leading to the imine derivative [OsCl(CO){η1-NHC(H)C6H4-4-
CH3}(PPh3)2{P(OEt)3}]BPh4 (8b). Hydrazine complexes [OsCl(CO)(RNHNH2)(PPh3)2L]BPh4 (9−11) [R = H, CH3, C6H5;
L = P(OMe)3, P(OEt)3] were prepared by allowing hydride species OsHCl(CO)(PPh3)2L (2) to react first with triflic acid and
then with an excess of hydrazine. Aryldiazene derivatives [OsCl(CO)(ArNNH)(PPh3)2L]BPh4 (12, 13) were also prepared
following two different methods: (i) by oxidizing arylhydrazine [OsCl(C6H5NHNH2)(CO)(PPh3)2L]BPh4 (11) with Pb(OAc)4
in CH2Cl2 at −30 °C; (ii) by allowing hydride species OsHCl(CO)(PPh3)2L (2) to react with aryldiazonium cations ArN2+ (Ar
= C6H5, 4-CH3C6H4) in CH2Cl2. The complexes were characterized spectroscopically and by X-ray crystal structure
determination of OsHCl(CO)(PPh3)2[P(OEt)3] (2b) and [OsCl{η1-NHC(H)C6H4-4-CH3}(CO)(PPh3)2{P(OEt)3}]BPh4
(8b).
Chart 1
INTRODUCTION
■
The reaction of organic azides with transition metal complexes
has attracted considerable interest in recent years, due to the
variety of metal derivatives which can be prepared.1−9 Loss of
N2 is easy in organic azides and leads to the nitrene RN:
moiety, which can be incorporated either as a coordinate imido
ligand or as the product of a coupling or insertion reaction
between RN: and another coordinate ligand.2−4 Imido [M]
NR and tetraazabutadiene [M](η2-RNNNNR) com-
plexes are the most common products of the reaction of RN3
with metal complexes.2−4 However, in the first step of the
interaction between RN3 and a metal fragment, organic azide
was believed to η1-coordinate to the metal center, giving an
azido complex as intermediate. Although there is a significant
interest in these intermediates, their isolation and character-
ization is difficult and stable metal complexes containing
organic azide ligands are rare.5−8 These include V(V), Fe(I),
Ta(V), and W(V) mononuclear complexes,5 containing the
bent moiety NNN [A] (Chart 1), Cu(I), Ag(I), Pd(II), and
Ir(III) derivatives,6,7 with “linear” organoazide ligands [B], [C],
and a Ni(0) complex8a with η2-coordination of the RN3 ligand
[E]. A mixed-metallic zirconium(IV)−iridium(III) complex
containing a bridging PhNNN [D] group is also reported.8b
We are interested in the chemistry of diazo and triazo
complexes of transition metals and have reported the synthesis
Received: September 10, 2012
© XXXX American Chemical Society
A
dx.doi.org/10.1021/ic302483e | Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
was removed under reduced pressure to give an oil, which was
triturated with ethanol (3 mL). A white solid slowly separated out,
which was filtered and crystallized from dichloromethane and ethanol;
yield ≥ 85%.
and reactivity of hydrazine, diazene, diazenido, and triazene
derivatives of Mn10 and Fe11 triads and, recently, the first
benzylazide complexes of iridium7 stabilized by phosphites
P(OR)3 as supporting ligands. We thought of extending our
studies on azo complexes with the additional aim of preparing
organic azide complexes of the iron triad. As the use of metal
fragments MHL4 and ML4 containing phosphites P(OR)3
and PPh(OR)2 as ligands failed to stabilize organic azide
complexes, we decided to try mixed-ligand complexes, to test
whether coordination of RN3 on metal fragments could take
place. The results of a study on osmium, which allowed the
preparation of the first organic azide complexes for this metal,
are reported here.
Anal. Calcd for C40H40ClO4OsP3 (903.35) (2a). C, 53.18; H, 4.46;
1
Cl, 3.92. Found: C, 53.35; H, 4.34; Cl, 4.13%. H NMR (CD2Cl2, 25
°C) δ: 7.74, 7.36 (m, 30 H, Ph), 3.25 (d, 9 H, CH3), −5.54 ppm (dt, 1
H, OsH, JPH = 138.0, JPH = 21.0 Hz). 31P{1H} NMR (CD2Cl2, 20 °C)
δ: AB2 spin syst, δA 100.9, δB 9.2, JAB = 19.5 Hz. IR (KBr): νCO 1946
(s) cm−1.
+
2+
Anal. Calcd for C43H46ClO4OsP3 (945.43) (2b). C, 54.63; H, 4.90;
1
Cl, 3.75. Found: C, 54.44; H, 5.02; Cl, 3.58%. H NMR (CD2Cl2, 25
°C) δ: 7.76−7.34 (m, 30 H, Ph), 3.60 (qnt, 6 H, CH2), 0.99 (t, 9 H,
CH3), −5.68 ppm (dt, 1 H, OsH, JPH = 133.0, JPH = 22.0 Hz). 31P{1H}
NMR (CD2Cl2, 20 °C) δ: AB2 spin syst, δA 100.7, δB 9.1, JAB = 19.5
Hz. IR (KBr): νCO 1948 (s) cm−1.
EXPERIMENTAL SECTION
■
OsCl2(CO)(PPh3)3 (3) and OsCl2(CO)(PPh3)2L (4) [L = P(OMe)3
(a), P(OEt)3 (b)]. A slight excess of HCl (0.21 mmol, 0.105 mL of a 2
mol dm−3 solution in diethylether) was added to a solution of the
appropriate carbonyl complex OsHCl(CO)(PPh3)3 or OsHCl(CO)-
(PPh3)2L (0.20 mmol) in dichloromethane, cooled to −196 °C. The
solution was left to reach room temperature, stirred for 2 h, and then
the solvent removed under reduced pressure. The oil obtained was
triturated with ethanol (2 mL) until a green solid separated out, which
was filtered and crystallized from toluene and ethanol; yield ≥ 80%.
Anal. Calcd for C55H45Cl2OOsP3 (1076.00) (3). C, 61.39; H, 4.22;
General Comments. All reactions were carried out in an inert
atmosphere (argon) by means of standard Schlenk techniques or in an
inert-atmosphere glovebox. Once isolated, the complexes were found
to be relatively stable in air but were stored under nitrogen at −25 °C.
All solvents were dried over appropriate drying agents, degassed on a
vacuum line, and distilled into vacuum-tight storage flasks. OsO4 was a
Pressure Chemical Co. (USA) product, used as received. The
phosphites P(OMe)3 and P(OEt)3 were Aldrich products, purified
by distillation under nitrogen. Benzyl12 and phenyl13 azides were
prepared following methods previously reported. The labeled azide 4-
CH3C6H4CH215N3 was prepared by following the same method,12 by
reacting Na[15NNN] (98% enriched, CIL) with 4-methylbenzylbro-
mide 4-CH3 C6 H4 CH2 Br. Equimolar mixtures of 4-
CH3C6H4CH215NNN and 4-CH3C6H4CH2NN15N were obtained.
Hydrazine (1 mol dm−3 solution in THF) and methyl and phenyl
hydrazines were Aldrich products, used as received. Diazonium salts
1
Cl, 6.59. Found: C, 61.60; H, 4.09; Cl, 6.42%. H NMR (CD2Cl2, 25
°C) δ: 7.78−7.05 ppm (m, 45 H, Ph). 31P{1H} NMR (CD2Cl2, 20 °C)
δ: A2B spin syst, δA −10.73, δB −17.33, JAB = 12.1 Hz. IR (KBr): νCO
1954 (s); νOsCl 323, 294 (m) cm−1.
Anal. Calcd for C40H39Cl2O4OsP3 (937.79) (4a). C, 51.23; H, 4.19;
1
Cl, 7.56. Found: C, 51.04; H, 4.31; Cl, 7.38%. H NMR (CD2Cl2, 25
°C) δ: 7.94, 7.35 (m, 30 H, Ph), 3.25 ppm (d, 9 H, CH3). 31P{1H}
NMR (CD2Cl2, 20 °C) δ: AB2 spin syst, δA 74.3, δB −8.9, JAB = 23.1
Hz. IR (KBr): νCO 1969 (s); νOsCl 341, 305 (m) cm−1.
ArN2 BF4 were obtained in the usual way.14 Labeled diazonium
+
−
15
tetrafluoroborate [C6H5N N]BF4 was prepared from Na15NO2
(99% enriched, CIL) and aniline.
Anal. Calcd for C43H45Cl2O4OsP3 (979.87) (4b). C, 52.71; H, 4.63;
1
Other reagents were purchased from commercial sources in the
highest available purity and used as received. Infrared spectra were
recorded on a Perkin-Elmer Spectrum-One FT-IR spectrophotometer.
NMR spectra (1H, 31P, 15N) were obtained on an AVANCE 300
Bruker spectrometer at temperatures between −90 and +30 °C, unless
Cl, 7.24. Found: C, 52.87; H, 4.72; Cl, 7.09%. H NMR (CD2Cl2, 25
°C) δ: 7.91, 7.35 (m, 30 H, Ph), 3.55 (qnt, 6 H, CH2), 0.99 ppm (t, 9
H, CH3). 31P{1H} NMR (CD2Cl2, 20 °C) δ: AB2 spin syst, δA 70.1, δB
−6.58, JAB = 23.1 Hz. IR (KBr): νCO 1982 (s) cm−1.
[OsCl(η1-N3CH2Ar)(CO)(PPh3)2{P(OEt)3}]BPh4 (5b, 6b) [Ar = 4-
CH3C6H4 (5), C6H5 (6)] and [OsCl(η1-N3C6H5)(CO)(PPh3)2{P-
(OEt)3}]BPh4 (7b). Triflic acid (0.12 mmol, 10.6 μL) was added to
a solution of OsHCl(CO)(PPh3)2[P(OEt)3] (2b) (0.12 mmol, 110
mg) in 5 mL of CH2Cl2 cooled to −196 °C. The reaction mixture was
left to reach room temperature, stirred for 1 h, and then cooled again
to −196 °C. An excess of the appropriate azide (0.4 mmol) was added
to the resulting solution, which was brought to room temperature and
stirred for 5 h. The solvent was removed under reduced pressure to
give an oil, which was treated with ethanol (2 mL) containing an
excess of NaBPh4 (0.2 mmol, 68 mg). A pale-yellow solid slowly
separated out, which was filtered and crystallized from dichloro-
methane and ethanol; yield ≥ 65%.
1
otherwise noted. H spectra are referred to internal tetramethylsilane;
31P{1H} chemical shifts are reported with respect to 85% H3PO4,
whereas 15N shifts to CH315NO2; in both cases, downfield shifts are
considered positive. COSY, HMQC, and HMBC NMR experiments
were performed with standard programs. The iNMR software
package15 was used to process NMR data. The conductivity of 10−3
mol dm−3 solutions of the complexes in CH3NO2 at 25 °C was
measured on a Radiometer CDM 83. Elemental analyses were
determined in the Microanalytical Laboratory of the Dipartimento di
Scienze Farmaceutiche, University of Padova (Italy).
Synthesis of Complexes. The complex OsCl2(PPh3)3 was
obtained following the method previously reported.16
OsHCl(CO)(PPh3)3 (1). In a 100-mL three-necked round-bottomed
flask were placed 1 g of OsCl2(PPh3)3 (0.95 mmol), 0.3 g (4.6 mmol)
of zinc dust, and 30 mL of ethanol. The reaction mixture was refluxed
for 4 h and then the volume was reduced to about 10 mL by
evaporation of the solvent under reduced pressure. The orange solid
which separated out was filtered and crystallized by dissolving it in
toluene and, after filtration and concentration of the solution, by
adding enough ethanol to precipitate the complex; yield ≥ 65%. Anal.
calcd for C55H46ClOOsP3 (1041.56): C, 63.42; H, 4.45; Cl, 3.40.
Anal. Calcd for C75H74BClN3O4OsP3 (1410.82) (5b). C, 63.85; H,
5.29; N, 2.98; Cl, 2.51. Found: C, 63.45; H, 5.40; N, 3.09; Cl, 2.33%.
1
ΛM = 52.6 Ω−1 mol−1 cm2. H NMR (CD2Cl2, 25 °C) δ: 7.69−6.77
(m, 54 H, Ph), 4.23 (s, 2 H, CH2N3), 3.54 (qnt, 6 H, CH2 phos), 2.37
(s, 3 H, CH3 p-tolyl), 1.05 ppm (t, 9 H, CH3 phos). 31P{1H} NMR
(CD2Cl2, −30 °C) δ: AB2 spin syst, δA 65.9, δB −4.7, JAB = 27.0 Hz. IR
(KBr): ν 2146 (m); νCO 1952 (s) cm−1.
N
3
Anal. Calcd for C74H72BClN3O4OsP3 (1396.80) (6b). C, 63.63; H,
5.20; N, 3.01; Cl, 2.54. Found: C, 63.52; H, 5.09; N, 2.96; Cl, 2.38%.
1
Found: C, 63.18; H, 4.56; Cl, 3.23%. H NMR (CD2Cl2, 25 °C) δ:
1
ΛM = 55.1 Ω−1 mol−1 cm2. H NMR (CD2Cl2, 25 °C) δ: 7.95−6.87
7.68−7.02 (m, 45 H, Ph), −6.95 ppm (dt, 1 H, OsH, JPH = 87.0, JPH
=
(m, 55 H, Ph), 4.34 (s, 2 H, CH2N3), 3.55 (qnt, 6 H, CH2 phos), 1.05
25.0 Hz). 31P{1H} NMR (CD2Cl2, 20 °C) δ: A2B spin syst, δA 8.43, δB
−8.5, JAB = 11.0 Hz. IR (KBr): νOsH 2090 (w); νCO 1910 (s) cm−1.
OsHCl(CO)(PPh3)2L (2) [L = P(OMe)3 (a), P(OEt)3 (b)]. An excess
of the appropriate phosphite P(OR)3 (1.5 mmol) was added to a
solution of OsHCl(CO)(PPh3)3 (1) (0.5 g, 0.48 mmol) in 15 mL of
toluene, and the reaction mixture was refluxed for 45 min. The solvent
ppm (t, 9 H, CH3 phos). 31P{1H} NMR (CD2Cl2, −30 °C) δ: AB2
N
spin syst, δA 64.9, δB −4.8, JAB = 27.1 Hz. IR (KBr): ν 2141 (m); νCO
3
1955 (s) cm−1.
Anal. Calcd for C73H70BClN3O4OsP3 (1382.77) (7b). C, 63.41; H,
5.10; N, 3.04; Cl, 2.56. Found: C, 63.18; H, 5.22; N, 2.91; Cl, 2.43%.
B
dx.doi.org/10.1021/ic302483e | Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
1
ΛM = 53.9 Ω−1 mol−1 cm2. H NMR (CD2Cl2, 25 °C) δ: 7.92−6.87
(m, 55 H, Ph), 3.58 (qnt, 6 H, CH2), 1.04 ppm (t, 9 H, CH3). 31P{1H}
NMR (CD2Cl2, −30 °C) δ: AB2 spin syst, δA 69.9, δB −6.7, JAB = 27.7
Anal. Calcd for C70H67BClN2O4OsP3 (1329.71) (11a). C, 63.23; H,
5.08; N, 2.11; Cl, 2.67. Found: C, 63.01; H, 5.17; N, 2.00; Cl, 2.54%.
1
ΛM = 53.4 Ω−1 mol−1 cm2. H NMR (CD2Cl2, 20 °C) δ: 7.73−6.87
Hz. IR (KBr): ν 2124 (m); νCO 1959 (s) cm−1.
N
(m, 55 H, Ph), 4.78 (t br, 1 H, NH), 4.46 (m br, 2 H, NH2), 3.27 ppm
(d, 9 H, CH3). 31P{1H} NMR (CD2Cl2, 25 °C) δ: AB2 spin syst, δA
73.35, δB −4.60, JAB = 26.7 Hz. IR (KBr): νNH 3379 (w), 3355 (m);
νCO 1964 (s) cm−1.
3
[OsCl(η1-15N3CH2C6H4-4-CH3)(CO)(PPh3)2{P(OEt)3}]BPh4 (5b1).
This complex was prepared exactly like the related unlabeled derivative
5b, using 4-CH3C6H4CH215N3 as a reagent. H NMR (CD2Cl2, 25
1
°C) δ: 7.69−6.77 (m, 54 H, Ph), 4.28 (s, 2 H, CH215N3), 3.55 (qnt, 6
H, CH2 phos), 2.37 (s, 3 H, CH3 p-tolyl), 1.05 ppm (t, 9 H, CH3
phos). 31P{1H} NMR (CD2Cl2, −30 °C) δ: AB2X spin syst (X = 15N),
δA 65.15, δB −5.09, JAB = 27.2, JAX = 55.7, JBX = 27.7 Hz. 15N NMR
(CD2Cl2, −30 °C) δ: −69.6 (s, 15N), −368.4 ppm (m, 15N). IR (KBr):
Anal. Calcd for C73H73BClN2O4OsP3 (1371.79) (11b). C, 63.92; H,
5.36; N, 2.04; Cl, 2.58. Found: C, 63.72; H, 5.25; N, 2.13; Cl, 2.50%.
1
ΛM = 52.5 Ω−1 mol−1 cm2. H NMR (CD2Cl2, 20 °C) δ: 7.75−6.87
(m, 55 H, Ph), 4.83 (t br, 1 H, NH), 4.31 (m br, 2 H, NH2), 3.61 (qnt,
6 H, CH2), 1.14 ppm (t, 9 H, CH3). 31P{1H} NMR (CD2Cl2, 25 °C)
δ: AB2 spin syst, δA 78.9, δB 5.0, JAB = 26.7 Hz. IR (KBr): νNH 3249
(w), 3318 (m); νCO 1956 (s) cm−1.
2118 (m); νCO 1953 (s) cm−1.
15N3
ν
[OsCl{η1-NHC(H)C6H4-4-CH3}(CO)(PPh3)2{P(OEt)3}]BPh4
[OsCl(C6H5NNH)(CO)(PPh3)2L]BPh4 (12) [L = P(OMe)3 (a),
P(OEt)3 (b)]. Method A: A solid sample of the appropriate
phenylhydrazine complex [OsCl(C6H5NHNH2)(CO)(PPh3)2L]BPh4
(11) (0.1 mmol) was placed in a 25-mL three-necked round-bottomed
flask fitted with a solid-addition side arm containing a slight excess of
Pb(OAc)4 (0.11 mmol, 49 mg). Dichloromethane (8 mL) was added,
the solution cooled to −30 °C and Pb(OAc)4 portionwise was added
over 20−30 min to the cold stirring solution. The solution was
brought to 0 °C, stirred for 5 min, and then the solvent was removed
at 0 °C under reduced pressure. The oil obtained was triturated with
ethanol (2 mL) containing NaBPh4 (0.1 mmol, 34 mg), and the
resulting solution was stirred at 0 °C until a pale-yellow solid separated
out, which was filtered and crystallized from CH2Cl2 and ethanol; yield
≥ 55%.
(8b). A solution of the complex [OsCl(η1-N3CH2C6H4-4-CH3)(CO)-
(PPh3)2{P(OEt)3}]BPh4 (5b) (100 mg, 0.07 mmol) in CH2Cl2 (5
mL) and EtOH (7 mL) was stirred at room temperature in the
daylight for 10 h. The solvent was then removed under reduced
pressure to give an oil, which was treated with ethanol (2 mL)
containing NaBPh4 (0.1 mmol, 34 mg). A white solid slowly separated
out, which was filtered and crystallized from dichloromethane and
ethanol; yield ≥ 60%. Anal. calcd for C75H74BClNO4OsP3 (1382.81):
C, 65.14; H, 5.39; N, 1.01; Cl, 2.56. Found: C, 64.98; H, 5.51; Cl,
2.42%. ΛM = 53.0 Ω−1 mol−1 cm2. H NMR (CD2Cl2, 25 °C) δ: 8.29
1
(d br, 1 H, NH, JHH = 22.0), 7.75 (d, 1 H, NCH, JHH = 22.0 Hz),
7.91−6.87 (m, 54 H, Ph), 3.55 (qnt, 6 H, CH2 phos), 2.39 (s, 3 H,
CH3 p-tolyl), 0.99 ppm (t, 9 H, CH3 phos). 31P{1H} NMR (CD2Cl2,
25 °C) δ: AB2 spin syst, δA 70.0, δB −6.5, JAB = 23.0 Hz. IR (KBr): νNH
3289 (m); νCO 1952 (s) cm−1.
Anal. Calcd for C70H65BClN2O4OsP3 (1327.69) (12a). C, 63.32; H,
4.93; N, 2.11; Cl, 2.67. Found: C, 63.11; H, 5.02; N, 2.17; Cl, 2.55%.
[OsCl(RNHNH2)(CO)(PPh3)2L]BPh4 (9−11) [R = H (9), CH3 (10),
C6H5 (11); L = P(OMe)3 (a), P(OEt)3 (b)]. Triflic acid (0.11 mmol, 9.7
μL) was added to a solution of the appropriate complex OsHCl-
(CO)(PPh3)2L (2) (0.1 mmol) in 5 mL of CH2Cl2 cooled to −196
°C. The reaction mixture was brought to room temperature, stirred for
1 h, and then cooled again to −196 °C. An excess of the appropriate
hydrazine (0.22 mmol) was added to the resulting solution, which was
brought to room temperature and stirred for 3 h. The solvent was
removed under reduced pressure to give an oil, which was treated with
ethanol (2 mL) containing an excess of NaBPh4 (0.2 mmol, 68 mg). A
white solid slowly separated out, which was filtered and crystallized
from dichloromethane and ethanol; yield ≥ 75%.
Λ
M = 51.1 Ω−1 mol−1 cm2. 1H NMR (CD2Cl2, 20 °C) δ: 12.46 (d br, 1
H, NH, JPH = 12.0 Hz), 7.94−6.66 (m, 55 H, Ph), 3.25 ppm (d, 9 H,
CH3). 31P{1H} NMR (CD2Cl2, 25 °C) δ: AB2 spin syst, δA 80.56, δB
−7.40, JAB = 27.9 Hz. IR (KBr): νCO 1982 (s) cm−1.
Anal. Calcd for C73H71BClN2O4OsP3 (1369.77) (12b). C, 64.01; H,
5.22; N, 2.05; Cl, 2.59. Found: C, 63.83; H, 5.38; N, 2.17; Cl, 2.45%.
Λ
M = 52.7 Ω−1 mol−1 cm2. 1H NMR (CD2Cl2, 20 °C) δ: 12.34 (d br, 1
H, NH, JPH = 12.7 Hz), 7.92−6.65 (m, 55 H, Ph), 3.50 (qnt, 6 H,
CH2), 1.04 ppm (t, 9 H, CH3). 31P{1H} NMR (CD2Cl2, 25 °C) δ: AB2
spin syst, δA 77.1, δB −7.9, JAB = 27.3 Hz. IR (KBr): νCO 1974 (s)
cm−1.
[OsCl(ArNNH)(CO)(PPh3)2L]BPh4 (12, 13) [Ar = C6H5 (12), 4-
CH3C6H4 (13); L = P(OMe)3 (a), P(OEt)3 (b)]. Method B: in a 25-mL
three-necked round-bottomed flask were placed solid samples of the
appropriate carbonyl complex OsHCl(CO)(PPh3)2L (2) (0.1 mmol),
an excess of the appropriate aryldiazonium cation [ArN2]BF4 (0.25
mmol), and 10 mL of CH2Cl2. The reaction mixture was stirred at
room temperature for 4 h, and then, the solvent was removed under
reduced pressure. The oil obtained was treated with ethanol (2 mL)
containing an excess of NaBPh4 (0.2 mmol, 68 mg). The resulting
solution was stirred until a pale-yellow solid separated out, which was
filtered and crystallized from CH2Cl2 and EtOH; yield ≥ 80.
Anal. Calcd for C71H67BClN2O4OsP3 (1341.72) (13a). C, 63.56; H,
5.03; N, 2.09; Cl, 2.64. Found: C, 63.34; H, 4.92; Cl, 2.75; N, 1.98%.
Anal. Calcd for C64H63BClN2O4OsP3 (1253.61) (9a). C, 61.32; H,
5.07; N, 2.23; Cl, 2.83. Found: C, 61.07; H, 5.20; N, 2.11; Cl, 2.96%.
1
ΛM = 54.6 Ω−1 mol−1 cm2. H NMR (CD2Cl2, 20 °C) δ: 7.96−6.80
(m, 50 H, Ph), 4.00 (br, 2 H, NH2), 3.18 (d, 9 H, CH3), 2.68 ppm (m
br, 2 H, NH2). 31P{1H} NMR (CD2Cl2, 25 °C) δ: AB2 spin syst, δA
76.9, δB −5.02, JAB = 26.7 Hz. IR (KBr): νNH 3367, 3278, 3216 (w);
νCO 1963 (s) cm−1.
Anal. Calcd for C67H69BClN2O4OsP3 (1295.69) (9b). C, 62.11; H,
5.37; N, 2.16; Cl, 2.74. Found: C, 62.29; H, 5.24; N, 2.24; Cl, 2.52%.
1
ΛM = 53.6 Ω−1 mol−1 cm2. H NMR (CD2Cl2, 20 °C) δ: 7.90−6.86
(m, 50 H, Ph), 3.55 (m, 6 H, CH2), 3.13, 2.70 (m br, 4 H, NH2), 1.00
ppm (t, 9 H, CH3). 31P{1H} NMR (CD2Cl2, 25 °C) δ: AB2 spin syst,
δA 68.2, δB 7.83, JAB = 22.0 Hz. IR (KBr): νNH 3339 (w), 3272 (m),
3253 (w); νCO 1967 (s) cm−1.
Λ
M = 54.4 Ω−1 mol−1 cm2. 1H NMR (CD2Cl2, 20 °C) δ: 12.22 (d br, 1
H, NH), 7.92−6.59 (m, 54 H, Ph), 3.25 (d, 9 H, CH3 phos), 2.39 ppm
(s, 3 H, CH3 p-tolyl). 31P{1H} NMR (CD2Cl2, 25 °C) δ: AB2 spin syst,
δA 80.9, δB −7.25, JAB = 27.0 Hz. IR (KBr): νCO 1970 (s) cm−1.
Anal. Calcd for C74H73BClN2O4OsP3 (1383.80) (13b). C, 64.23; H,
5.32; N, 2.02; Cl, 2.56. Found: C, 64.01; H, 5.43; N, 2.12; Cl, 2.43%.
Anal. Calcd for C65H65BClN2O4OsP3 (1267.64) (10a). C, 61.59; H,
5.17; N, 2.21; Cl, 2.80. Found: C, 61.36; H, 5.04; N, 2.30; Cl, 2.68%.
1
ΛM = 51.4 Ω−1 mol−1 cm2. H NMR (CD2Cl2, 20 °C) δ: 7.79−6.88
(m, 50 H, Ph), 3.87 (m br, 2 H, NH2), 3.14 (d, 9 H, CH3 phos), 2.71
(m, 1 H, NH), 1.50 ppm (d, 3 H, NCH3). 31P{1H} NMR (CD2Cl2, 25
°C) δ: AB2 spin syst, δA 77.2, δB −4.39, JAB = 26.7 Hz. IR (KBr): νNH
3310 (w), 3254 (m), 3183 (w); νCO 1964 (s) cm−1.
Λ
M = 53.6 Ω−1 mol−1 cm2. 1H NMR (CD2Cl2, 20 °C) δ: 12.11 (d br, 1
H, NH, JPH = 8.0 Hz), 7.80−6.57 (m, 54 H, Ph), 3.50 (m, 6 H, CH2),
2.39 (s, 3 H, CH3 p-tolyl), 1.04 ppm (d, 9 H, CH3 phos). 31P{1H}
NMR (CD2Cl2, 25 °C) δ: AB2 spin syst, δA 77.41, δB −7.78, JAB = 26.7
Hz. IR (KBr): νCO 1969 (s) cm−1.
Anal. Calcd for C68H71BClN2O4OsP3 (1309.72) (10b). C, 62.36; H,
5.46; N, 2.14; Cl, 2.71. Found: C, 62.13; H, 5.34; N, 2.06; Cl, 2.82%.
1
ΛM = 55.7 Ω−1 mol−1 cm2. H NMR (CD2Cl2, 20 °C) δ: 7.81−6.84
15
[OsCl(CO)(C6H5N NH)(PPh3)2{P(OEt)3}]BPh4 (12b1). This
(m, 50 H, Ph), 3.74 (br, 2 H, NH2), 3.38 (qnt, 6 H, CH2), 2.75 (m, 1
H, NH), 1.52 (d, 3 H, NCH3), 0.97 ppm (t, 9 H, CH3 phos). 31P{1H}
NMR (CD2Cl2, 25 °C) δ: AB2 spin syst, δA 73.8, δB −4.83, JAB = 26.7
Hz. IR (KBr): νNH 3310 (w), 3258 (m), 3183 (w); νCO 1962 (s) cm−1.
complex was prepared exactly like the related unlabeled derivative
15
−
1
12b (method B), using [C6H5N N]+BF4 as a reagent. H NMR
1
15
1
N
31P
(CD2Cl2, 20 °C) δ: 12.34 (dd, 1 H, NH, J H = 65.11, J H = 12.7
Hz), 7.91−6.65 (m, 55 H, Ph), 3.50 (qnt, 6 H, CH2), 1.04 ppm (t, 9
C
dx.doi.org/10.1021/ic302483e | Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
H, CH3). 31P{1H} NMR (CD2Cl2, 25 °C) δ: AB2X spin syst (X =
15N), δA 77.1, δB −7.96, JAB = 27.2, JAX = 66.5, JBX = 3.1 Hz. 15N NMR
(CD2Cl2, 25 °C) δ: AB2X spin syst, δX −20.4, JAX = 66.5, JBX = 3.1 Hz.
IR (KBr): νCO 1974 (s) cm−1.
X-ray Crystallography. Crystallographic data were collected on a
Bruker Smart 1000 CCD diffractometer at CACTI (Universidade de
Vigo) using graphite monochromated Mo Kα radiation (λ = 0.71073
Å) and were corrected for Lorentz and polarization effects. The
software SMART17 was used for collecting frames of data, indexing
reflections, and the determination of lattice parameters, SAINT18 for
integration of intensity of reflections and scaling, and SADABS19 for
empirical absorption correction.
Table 1. Crystal Data and Structure Refinement
identification
code
2b
8b
empirical formula C43H46ClO4P3Os
C75H74BClNO4P3Os
1382.81
formula weight
temperature
wavelength
945.43
293(2) K
0.71073 Å
monoclinic
P21/c
293(2) K
0.71073 Å
crystal system
space group
monoclinic
P21/n
unit cell
dimensions
a = 17.808(6) Å
a = 22.554(3) Å
The structure of 2b was solved by direct methods using SIR9220
implemented in the WingX package.21 The structure of 8b was solved
by Patterson methods. Both were refined by full-matrix least-squares
on all F2 using SHELXL9722 by using the Oscail suite.23 Non-
hydrogen atoms were refined with anisotropic displacement
parameters, but some restraints were included in the model of 8b in
order to maintain the toluene ring atoms fitted to a regular hexagon.
The carbonyl and Cl sites are probably disordered over two positions
(as found for other structures containing Cl trans to CO), but the
quality of the crystal does not allow us to find the other counterpart.
The hydrogen atoms were included in idealized positions except that
bonded to the osmium metal, which was found in the density map. All
hydrogen atoms were refined with isotropic displacement parameters.
Details of crystal data and structural refinement are given in Table 1,
selected bond lengths and angles are shown in Table 2, and more data
are in the Supporting Information.
b = 10.058(4) Å
c = 24.423(9) Å
β = 110.671(5)°
4093(2) Å3
b = 12.7270(19) Å
c = 23.939(4) Å
β = 94.797(3)°
6847.5(17) Å3
4
volume
Z
4
density
(calculated)
1.534 Mg/m3
1.341 Mg/m3
absorption
coefficient
3.338 mm−1
2.020 mm−1
F(000)
1896
2824
crystal size
0.52 × 0.48 × 0.37 mm
1.77−28.06°
0.43 × 0.14 × 0.06 mm
1.19−28.05°
theta range for
data collection
index ranges
−23 ≤ h ≤ 23; −13 ≤ k ≤ −29 ≤ h ≤ 29; −16 ≤ k ≤
13; −31 ≤ l ≤ 32 16; −21 ≤ l ≤ 31
37532 44460
reflections
collected
RESULTS AND DISCUSSION
independent
9831 [R(int) = 0.0321]
16271 [R(int) = 0.1398]
■
reflections
Preparation of Hydride Precursors. The hydridocarbon-
yl complex OsHCl(CO)(PPh3)3 (1) was first prepared by
Vaska24 by treating (NH4)2OsCl6 with PPh3 in high-boiling
alcohols. We found that 1 can also be prepared in good yield by
refluxing the dichloro compound OsCl2(PPh3)3 in ethanol in
the presence of zinc dust or magnesium turnings. The addition
of the metal, Zn or Mg, is crucial for successful synthesis;
otherwise only traces of the hydridocarbonyl complex 1 are
obtained.
Complex 1 reacts with an excess of phosphites P(OR)3 in
toluene to give mixed-ligand derivatives OsHCl(CO)(PPh3)2L
(2), which were isolated in good yield and characterized
(Scheme 1).
The reaction proceeds with the substitution of only one PPh3
ligand, affording the new hydridocarbonyl derivative 2,
containing two PPh3 and one phosphite as supporting ligands.
Hydridocarbonyl complexes OsHCl(CO)(PPh3)2L (1, 2) [L
= PPh3 or P(OR)3] react at low temperature (−80 °C) with
Brønsted acids HY with the evolution of H2 and the formation
of either pentacoordinate cations [OsCl(CO)(PPh3)2L]+ or
neutral compounds Os(Y)Cl(CO)(PPh3)2L, which were stable
in solution but decomposed on attempts at separating them in
the solid state (Scheme 2).
The progress of the reaction between complexes 1, 2 and
Brønsted acids was monitored by NMR measuremets at −80
°C. As 1 equiv of HY was added to the solution of 1 and 2 in
CD2Cl2, the 1H NMR spectra showed the disappearance of the
signals between −6.95 and −5.54 ppm of the hydride ligands
and the appearance of a new signal at about 4.6 ppm, which
decreased on shaking and was attributed to free H2.25 No new
signals attributable to a η2-H2 complex26 formed by protonation
were observed in the spectra, according to the reaction shown
in Scheme 2.
reflections
observed (>2σ)
7951
5946
data
completeness
0.989
0.980
absorption
correction
semiempirical from
equivalents
semiempirical from
equivalents
max and min
transmission
0.7456 and 0.4466
0.7456 and 0.6554
refinement
method
full-matrix least-squares on full-matrix least-squares on
F2
F2
data/restraints/
parameters
9831/0/476
16271/17/758
goodness-of-fit on 1.031
0.966
F2
final R indices [I R1 = 0.0301 wR2 = 0.0691 R1 = 0.0714 wR2 = 0.1637
> 2σ(I)]
R indices (all
data)
R1 = 0.0453 wR2 = 0.0778 R1 = 0.2350 wR2 = 0.2400
largest diff. peak
and hole
1.493 and −1.564 e Å−3 1.719 and −0.787 e Å−3
dichloro derivatives OsCl2(CO)(PPh3)2L (3, 4), as shown in
Scheme 3.
The reaction proceeds with the evolution of dihydrogen and
coordination of Cl−, giving the dichlorocarbonyl derivatives 3,
4, which were isolated and characterized.
The new carbonyl complexes 1−4 were all separated as
yellow (1, 3) or white (2, 4) solids, very stable in air and in
solution of common organic solvents, where they behave as
nonelectrolytes. Their characterization is supported by
analytical and spectroscopic (IR, NMR) data and by the X-
ray crystal structure determination of complex OsHCl(CO)-
(PPh3)2{P(OEt)3} (2b), whose ORTEP is shown in Figure 1.
In compound 2b, the osmium(II) atom is hexacoordinated
by a hydride atom, a chloride atom, a carbonyl ligand, and three
phosphorus atoms of three phosphane groups, two triphenyl-
phosphines and one triethylphosphite, in such a way that the
Hydrogen chloride HCl can also be used as a Brønsted acid
in the reaction with OsHCl(CO)(PPh3)2L (1, 2) leading to the
D
dx.doi.org/10.1021/ic302483e | Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
a
Table 2. Selected Bond Lengths [Å] and Angles [deg]
Scheme 3
2b
8b
lengths
Os−H(1)
Os−P(1)
Os−P(2)
Os−P(3)
Os−C(1)
Os−Cl
1.59(5)
Os−N(1)
Os−P(1)
Os−P(2)
Os−P(3)
Os−C(1)
Os−Cl
C(1)−O(1)
N(1)−C(2)
C(2)−C(3)
2.136(10)
2.295(3)
2.427(3)
2.431(3)
1.901(17)
2.429(3)
1.058(15)
1.194(18)
1.48(2)
2.3392(12)
2.3672(13)
2.3835(12)
1.839(4)
a
L = PPh3 (1, 3), P(OMe)3 (2a, 4a), P(OEt) (2b, 4b).
2.4739(11)
1.154(5)
3
C(1)−O(1)
angles
H(1)−Os−C(1)
H(1)−Os−Cl
89.2(16)
87.8(16)
176.0(17)
78.3(16)
82.4(16)
88.39(13)
90.36(12)
92.97(13)
176.99(13)
94.60(5)
98.50(4)
101.00(4)
160.30(3)
88.78(4)
86.84(3)
179.0(4)
N(1)−Os−C(1)
N(1)−Os−Cl
91.9(5)
85.1(3)
H(1)−Os−P(1)
H(1)−Os−P(2)
H(1)−Os−P(3)
C(1)−Os−P(1)
C(1)−Os−P(2)
C(1)−Os−P(3)
C(1)−Os−Cl
N(1)−Os−P(1)
N(1)−Os−P(2)
N(1)−Os−P(3)
C(1)−Os−P(1)
C(1)−Os−P(2)
C(1)−Os−P(3)
C(1)−Os−Cl
176.6(3)
84.8(2)
87.7(2)
85.2(4)
92.5(4)
91.8(4)
177.0(4)
97.79(11)
93.51(11)
94.18(11)
171.46(10)
87.51(11)
87.77(11)
177.8(16)
135(2)
P(1)−Os−Cl
P(1)−Os−Cl
P(1)−Os−P(2)
P(1)−Os−P(3)
P(2)−Os−P(3)
P(2)−Os−Cl
P(3)−Os−Cl
Os−C(1)−O(1)
P(1)−Os−P(2)
P(1)−Os−P(3)
P(2)−Os−P(3)
P(2)−Os−Cl
P(3)−Os−Cl
Os−C(1)−O(1)
Figure 1. ORTEP27 view (50% probability level) of complex 2b. The
ethoxy groups of the P(OEt)3 [P1] and the phenyl groups of the PPh3
[P2 and P3] were not drawn for clarity.
slightly longer than that of Os−P(phosphite) [2.339(1) Å]. The
difference between the two types of Os−P bond lengths is
smaller than expected but is probably due to the different trans
influence exerted on these ligands.30−32 The values for Os−
N(1)−C(2)−C(3)
Os−N(1)−C(2)
133.9(13)
a
P
(phosphine) bond lengths in 2b are identical to those found in the
Scheme 1
compound [OsCl{bis(quinolinyl)amidate)}(PPh3)2].33 Inci-
dentally, Os−P(phosphite) bond values in 2b are longer than
those found in the [Os(NH2NH2)2{P(OEt)3}4]2+ cation11d or
in [Os(SnH3)(Tp){P(OMe)3}(PPh3)].31
The IR spectrum of OsHCl(CO)(PPh3)3 (1) shows a strong
band at 1910 cm−1 attributed to the νCO of the carbonyl ligand.
The spectrum also shows a weak band at 2090 cm−1, attributed
to the νOsH of the hydride ligand. The presence of this ligand is
confirmed by the 1H NMR spectrum, which shows a doublet of
triplets at −6.95 ppm due to the resonance of the H− coupled
with the three phosphine ligands. The value of 87 Hz found for
one JPH, compared with the value of 25 Hz for the other two
JPH, suggests that the hydride is in trans position with respect to
one PPh3 and in cis with respect to the other two. The 31P
NMR spectrum is an A2B multiplet, indicating that the two
phosphines are magnetically equivalent and different from the
third. On this basis, mer geometry I may be proposed in
solution for the carbonyl compound 1.
The IR spectra of mixed-ligands complexes OsHCl(CO)-
(PPh3)2L (2) show the νCO as a strong band at 1946 (2a) and
1948 (2b) cm−1, which falls at a value slightly higher than in the
related complex 1, according to the better π-acceptor properties
of phosphites P(OR)3 with respect to PPh3. Instead, no bands
attributable to νOsH were observed in the spectra. However, the
presence of the hydride ligand is supported by the proton NMR
spectra, which show a doublet of triplets at −5.54 (2a) and
−5.68 (2b) ppm, due to the coupling of H− with the 31P nuclei
of phosphines. In addition, comparison of the two JPH values
suggests that the hydride is trans to one phosphine and in cis
with respect to the other two. The 31P NMR spectra appear as
a
R = Me (a), Et (b).
a
Scheme 2
a
−
Y− = CF3SO3 ; L = PPh3 (1), P(OMe)3 (2a), P(OEt)3 (2b).
PPh3 ligands are mutually trans and the P(OEt)3 one is trans to
the hydride ligand. The environment of the osmium atom is a
slightly distorted octahedron, in which the most important
source of distortion comes from bending of the axis P−Os−P,
with angle value of 160.30(3)°.28,11k The Os−C carbonyl bond
length, 1.839(4) Å, and that of the Os−Cl (trans to former),
2.474(1) Å, are both comparable with other trans compounds
and do not deserve further comment.29 The mutually trans
Os−P(phosphine) bond lengths [average 2.375(1) Å] are only
E
dx.doi.org/10.1021/ic302483e | Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
AB2 multiplets, suggesting that the two phosphines are
magnetically equivalent and different from the phosphite. On
the basis of these data, a mer geometry II (Scheme 1), like that
found in the solid state (Figure 1), may be proposed in solution
for the mixed-ligand species 2.
of polar organic solvents, where they behave as 1:1 electro-
lytes.35 Analytical and spectroscopic data (IR, H, 15N, 31P
1
NMR) support the proposed formulation, which was further
confirmed by X-ray crystal structure determination of the imine
complex [OsCl{η1-NHC(H)C6H4-4-CH3}(CO)(PPh3)2{P-
(OEt)3}]BPh4 (8b), formed from the azide derivative 5b (see
below, Figure 2).
The νCO band of dichloro complex OsCl2(CO)(PPh3)3 (3)
appears at 1954 cm−1, whereas those of the related derivatives
OsCl2(CO)(PPh3)2L (4) fall at 1969 (4a) and 1982 (4b) cm−1.
In the far region of the spectra, two medium-intensity
absorptions were also observed at 323 and 294 cm−1 for 3
and at 341 and 305 cm−1 for 4a, and were attributed to νOsCl of
two chloride ligands in a mutually cis position. The 31P NMR
spectra are either A2B (3) or AB2 (4) multiplets and can be
simulated with the parameters reported in the Experimental
Section, indicating that the two phosphines are magnetically
equivalent and different from the third. These spectroscopic
data alone do not allow us to decide unambiguously between
mer (III) and fac (IV) geometry for dichloro complexes 3, 4
(Chart 2).
The IR spectra of azide complexes 5−7 show a strong band
at 1952−1959 cm−1, due to the νCO of the carbonyl group, and
a medium-intensity one at 2146−2124 cm−1, attributed to the
νN of the azide ligand. Support for this attribution came from
3
the spectra of the labeled compound [OsCl(η1-15N3CH2C6H4-
4-CH3)(CO)(PPh3)2{P(OEt)3}]BPh4 (5b1), which showed the
ν
at 2118 cm−1, shifted to a lower wavenumber by 28 cm−1
15N3
with respect to the unlabeled 5b (Supporting Information
Figure S2). The high νN values of our complexes, compared
3
with those of azide complexes whose X-ray structures are
known,6,7 suggest the η1-diazoamino coordination mode [B]
(Chart 1) of the azide ligand (Scheme 5).
a
Chart 2
a
Scheme 5
a
L = PPh3 (3), P(OMe)3 (4a), P(OEt) (4b).
3
a
L = P(OMe)3 (a), P(OEt)3 (b).
However, comparison of their spectroscopic properties with
those of the related hydride-carbonyl complexes OsHCl(CO)-
(PPh3)2L (1, 2), containing the CO trans to the chloride ligand,
suggests that mer geometry III is the most plausible for 3 and
4.
Azide Complexes. Unsaturated mixed-ligand complexes
formed by protonation of hydrides OsHCl(CO)(PPh3)2L (2)
with Brønsted acids reacted with an excess of organic azide RN3
to give azide cations [OsCl(η1-N3R)(CO)(PPh3)2L]+ (5−7),
which were separated as BPh4− salts and characterized (Scheme
4).34
Variable-temperature NMR spectra of azide complexes 5−7
showed that the compounds are fluxional. The two broad
signals observed at room temperature in the 31P NMR spectra,
already at −30 °C, resolved into one triplet and one doublet,
which could be simulated with an AB2 model, indicating that
the two phosphine ligands are magnetically equivalent and
different from the third. In addition, the 15N NMR spectrum of
the labeled complex [OsCl(η1-15N3CH2C6H4-4-CH3)(CO)-
(PPh3)2{P(OEt)3}]BPh4 (5b1) may be used as a diagnostic
tool for the coordinate azide molecule. A singlet at −69.6 and a
multiplet at −368.4 ppm were observed in the spectrum at −30
°C and attributed to the Nα and Nγ nuclei, respectively, of the
coordinate 4-CH3C6H4CH215N3 group. Further support to the
coordination of the azide came from the 31P spectrum of the
labeled complex 5b1, showing two broad signals at room
temperature, which resolved (at −30 °C) into two multiplets,
simulable with an AB2X model (X = 15N) with the parameters
reported in the Experimental Section. The good fit between the
calculated and experimental spectra (Supporting Information
Instead, the related hydride OsHCl(CO)(PPh3)3 (1) did not
give azide complexes, after treatment first with Brønsted acid
and then with an excess of RN3. Similarly, the reaction of
dichloro complexes OsCl2(CO)(PPh3)2L (3, 4) with organic
azide did not afford the related complexes, and it seems that
only the mixed-ligand fragments [OsCl(CO)(PPh3)2{P-
(OR)3}]+, containing CO, PPh3, and phosphites, can stabilize
[Os]−η1-N3R derivatives.
Azide complexes [OsCl(η1-N3R)(CO)(PPh3)2L]+ (5−7) are
pale-yellow solids stable in air but slightly unstable in solution
a
Scheme 4
a
−
L = P(OMe)3 (a), P(OEt)3 (b); R = 4-CH3C6H4CH2 (5), C6H5CH2 (6), C6H5 (7); Y− = CF3SO3 .
F
dx.doi.org/10.1021/ic302483e | Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
Figure S1) strongly supports coupling of the 31P nuclei of
phosphines with the 15N nuclei of the coordinate azide group.
However, although spectroscopic data alone do not allow us to
assign unambiguously a geometry in solution for complexes 5−
7, comparison with the data of carbonyl precursor 2 and imine
complex [OsCl{η1-NHC(H)C6H4-4-CH3}(CO)(PPh3)2{P-
(OEt)3}]BPh4 (8b) (see below) allow us to propose geometry
V (Scheme 5) for our azide complexes 5−7.
Extrusion of N2 in coordinate azide 5, followed by 1,2-shift of
one hydrogen atom, may lead to the formation of imine
derivative 8. It should be noted that slow diffusion of ethanol
into a CH2Cl2 solution of 5b at 5 °C yielded crystals of imine
complex [OsCl{η1-NHC(H)C6H4-4-CH3}(CO)(PPh3)2{P-
(OEt)3}]BPh4 (8b) the structure of which is shown in Figure 2.
The fluxional behavior shown by azide complexes [OsCl(η1-
N3R)(CO)(PPh3)2L]BPh4 (5−7) may be explained by an
intermolecular process involving dissociation of the azide
ligand, as shown in Scheme 5. Strong support for such a
dissociation equilibrium of the azide ligand in the complexes
was obtained by adding free 15N-labeled azide 4-
CH3C6H4CH215N3 to the unlabeled compound 5a in an
NMR tube and observing that exchange between labeled and
unlabeled azide does take place. On the basis of these results,
the dissociation process of Scheme 5 may plausibly be proposed
to explain the VT-NMR behavior of our azide derivatives.
Transition metal complexes containing organic azide as a
ligand are rare5−8 and, to the best of our knowledge, there are
no reports of organoazide osmium complexes in the literature.
The use of the mixed-ligand precursors OsHCl(CO)(PPh3)2L
(2) allows easy synthesis of the first RN3 complexes for this
metal. Unfortunately, the bonding mode of the azide in our
compounds 5−7 could not be established by X-ray
determination and only IR data can give some information,
Figure 2. ORTEP27 view (20% probability level) of 8b. The ethoxy
groups of the P(OEt)3 [P1] and the phenyl groups of the PPh3 [P2
and P3] were not drawn for clarity.
suggesting linear Nγ coordination [B] (Chart 1). Values for νN
3
(2146−2124 cm−1) higher than those of the free RN3 ligand
were found in our complexes 5−7 and in those6,7 of Ag, Pd, Cu,
and Ir, in which Nγ coordination has been confirmed by X-ray
determination. Such a coordination through substituted Nγ is
favored by the greater Lewis basicity36 of the site and is
probably the most common type of azide complex with linear
NNN geometry. However, one example of Nα coordination of
the azide was also observed in complex6b HB[3,5-
(CF3)2Pz]3CuNNN(1-Ad) (Pz = pyrazolyl; 1-Ad = adamantyl)
but, according to theoretical calculations, was attributed to
Cu(I), which exhibits “enough π-donating ability to favor
binding through the terminal nitrogen”.
N-protio imine complexes of osmium are rare,37 and the
reaction of our benzylazide complex 5 allows a new example of
such imine species to be prepared.
Analytical and spectroscopic data support the proposed
formulation for imine complex 8b, which is a white solid stable
in air and in solution of polar organic solvents, where it behaves
as a 1:1 electrolyte.35 The IR spectrum shows a strong band at
1952 cm−1, attributed to the νCO of the carbonyl group, and a
medium-intensity absorption at 3289 cm−1, attributed to the
1
νNH of the imine ligand. Its presence is confirmed by the H
NMR spectrum, which shows a slightly broad doublet at 8.29
ppm (JHH = 22 Hz) attributed to the NH imine resonance. In a
COSY experiment, this signal was correlated with a doublet at
7.75 ppm, attributed to the CH signal of the imine. In the
temperature range +20 to −80 °C, the 31P NMR spectra of the
imine complex 8b appear as AB2 multiplets, indicating the
magnetic equivalence of the two phosphines, different from the
third. Although these data do not allow to assign
unambiguously a geometry in solution to 8b, they are not in
contrast with a type VI geometry, like that found in the solid
state.
It is worth noting that organic azide complexes are probably
involved as intermediates in the metal-catalyzed cycloaddition
of alkyne and organic azides to give triazole.9 Therefore, the
preparation of new RN3 complexes and information on the
coordination chemistry of RN3 may help to clarify the
mechanism of reaction and to find new catalysts.
Benzylazide complexes [OsCl(η1-N3CH2Ar)(CO)-
(PPh3)2{P(OEt)3}]BPh4 (5) are stable as solids, but slowly
react in solution to give a new compound, characterized as the
imine species [OsCl{η1-NHC(H)Ar}(CO)(PPh3)2{P-
(OEt)3}]BPh4 (8) (Scheme 6).
Conclusive support for the formulation of 8b came from X-
ray crystal structure determination. The asymmetric unit
a
−
Scheme 6
contains both an anion BPh4 and a cation complex. An
ORTEP view of the cation is show in Figure 2.
The Os(II) atom is coordinated by the nitrogen atom of a 4-
methylbenzylideneamidate ligand [bonded through the nitro-
gen atom: η1-NHC(H)C6H4CH3] trans to a phosphorus
atom of a triethoxyphosphine ligand. There is also a chloride
atom trans to a carbonyl ligand. The octahedron is completed
by two mutually trans phosphorus atoms of two triphenyl-
phosphine ligands. As stated in the Experimental Section, the
carbonyl and Cl sites are probably disordered over two
a
Ar = 4-CH3C6H4; L = P(OEt)3.
G
dx.doi.org/10.1021/ic302483e | Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
a
positions (as found for other structures containing Cl trans to a
carbonyl ligand),38,39 but the poor quality of the crystal did not
allow us to find the other counterpart. The presence of the
disorder limits discussion of the metrical parameters. Within
these margins, some features may be mentioned, as follows.
The environment of the osmium atom is a slightly distorted
octahedron, with cis angles ranging from 84.8(2) to 97.8(1)°.
The 4-methylbenzylideneamidate ligand is spatially arranged in
such a way that an interaction between N−H and the Cl ligand
is allowed.40 This means that the ligand plane is parallel to the
Cl−Os−carbonyl vector. Unfortunately, the parameters of this
interaction or planarity are very imprecise and cannot be
commented on further. The Os−N(amidate) bond distance,
2.14(1) Å, is shorter than those found for other single nitrogen
osmium bonds such as the hydrazine cation [Os(NH2NH2)2{P-
(OEt)3}4]+, 2.20(2) Å,11d or the aniline cation [Os(NH2Ph)-
H2(κ2-acetate)P2]+, 2.258(4) Å,32 but comparable with the
value found for neutral or cationic osmium imine complexes
[OsCl2−n(CCHPh)(NHCMe2)(H2O)n(PiPr3)2]n+ (n =
0, 1) [average 2.07(1) Å].40 This fact, together with the
parameters found around the N(3) atom discussed below,
suggests substantial delocalization in this ligand. The CN
bond distance, 1.19(2) Å, is also shorter than that found for
other benzylideneamido complexes with W,41 Re,42 Fe,43 Ru,37d
or Ir.7 The C(1)−N(3)−Os angle, 134(1)°, and the N(3)−
C(1)−C(2) angle, 135(2)°, are also very imprecise and also
surprisingly large for an sp2-hybridized N atom, but similar
values have been found for the above-mentioned W, Re, Fe, Ru,
and Ir complexes. The Os−P bond lengths are in two sets. The
bond length of Os−P(phosphite) is shorter [2.295(3) Å] than the
mutually trans Os−P(phosphine) one [average 2.429(3) Å]. It is
noteworthy that the former is shorter than that found in 2b, as
expected for the trans influence of hydride ligand versus an
amidate ligand. In contrast, Os−P(phosphine) bond lengths are
longer than those found in 2b.
Scheme 8
a
R = C6H5; L = P(OMe)3 (a), P(OEt)3 (b).
suggest that the selective oxidation of hydrazine to diazene does
occur in any case, but the instability of the compounds often
prevents their separation. Only the phenyl substituent therefore
seems to be able to stabilize the diazene derivative [OsCl-
(CO)(C6H5NNH)(PPh3)2L]BPh4 (12). It is worth noting
that the previously reported complex45 [OsCl(NH2NH2)-
(CO)2(PPh3)2]OTf reacted with Pb(OAc)4 to give the stable
and isolable derivative [OsCl(η1-NHNH)(CO)2(PPh3)2]-
OTf.
This result prompted us to test a different way of preparing
the same aryldiazene species by inserting aryldiazonium cations
into the Os−H bond. We therefore treated hydride OsHCl-
(CO)(PPh3)2L (2) with aryldiazonium cations and did observe
the formation of aryldiazene complexes [OsCl(CO)(ArN
NH)(PPh3)2L]BPh4 (12, 13), which were isolated in good
yield and characterized (Scheme 9).
a
Scheme 9
Hydrazine and Diazene Complexes. Unsaturated spe-
cies, formed by protonation of OsHCl(CO)(PPh3)2L with the
Brønsted acids HY, also react with hydrazines RNHNH2 to give
the related complexes [OsCl(CO)(RNHNH2)(PPh3)2L]BPh4
(9−11), which were isolated in good yield and characterized
(Scheme 7).
a
Ar = C6H5 (12), 4-CH3C6H4 (13); L = P(OMe)3 (a), P(OEt)3 (b).
The results highlight how aryldiazene complexes stabilized by
the carbonyl fragment [OsCl(CO)(PPh3)2L]+ may be prepared
either by oxidation of coordinate arylhydrazine or by insertion
of aryldiazonium cations into the Os−H bond. Over the past
thirty years, a number of hydrazine and aryldiazene complexes
have been reported for several transition metals11j,46 and have
been studied as models of the dinitrogen fixation process.
Hydrazine has also been shown to be a substrate of
nitrogenase47 and has been trapped as an intermediate during
enzyme turnover. However, although several hydrazine
complexes48 of various metals have been reported, relatively
few contain osmium. The use of the mixed-ligand hydride
OsHCl(CO)(PPh3)2L (2) as a precursor allows the synthesis of
new hydrazine and aryldiazene osmium derivatives.
a
Scheme 7
a
R = H (9), CH3 (10), C6H5 (11); L = P(OMe)3 (a), P(OEt)3 (b);
−
Y− = CF3SO3 .
Both hydrazine [OsCl(CO)(RNHNH2)(PPh3)2L]BPh4 (9−
11) and aryldiazene complexes [OsCl(CO)(ArNNH)-
(PPh3)2L]BPh4 (12, 13) were isolated as white or pale-yellow
solids stable in air and in solution of polar organic solvents,
where they behave as 1:1 electrolytes.35 Analytical and
spectroscopic data support the proposed formulation.
The IR spectra of hydrazine complexes 9−11 showed three
bands of medium intensity at 3379−3183 cm−1, attributed to
the νNH of the coordinate group. The spectra also show a strong
absorption at 1967−1956 cm−1, due to the νCO of the carbonyl
Hydrazine complexes 9−11 reacted with Pb(OAc)4 at −30
°C to give the diazene derivative [OsCl(CO)(RNNH)-
(PPh3)2L]+ (12) which, in the case of the phenyldiazene, was
isolated as a solid and characterized (Scheme 8).
Instead, in the case of hydrazine NH2NH2 and metylhy-
drazine CH3NHNH2 derivatives, the solids obtained contained
only little amounts of 1,2-diazene44 NHNH or methyl-
diazene CH3NNH complexes, which decomposed during
crystallization. However, even traces of the diazene ligand
H
dx.doi.org/10.1021/ic302483e | Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
1
ligand. The H NMR spectra confirm the presence of the
AUTHOR INFORMATION
Corresponding Author
*Fax: +39 041 234 8917. E-mail: albertin@unive.it.
Notes
■
hydrazine, showing one slightly broad multiplet at 4.00−3.13
ppm due to the metal-bonded NH2 group of NH2NH2 and
CH3NHNH2 ligands and another multiplet at 2.75−2.68 ppm
of the NH2 or NH protons of the hydrazine. A doublet at 1.52−
1.50 ppm of the methyl group of CH3NHNH2 also appears in
the spectra of 10. In addition, the signals of the phenyl-
hydrazine fall to 4.46−4.31 (NH2) and 4.83−4.78 ppm (NH),
indicating the presence of the diazo ligand.
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
We acknowledge support from MIUR (Rome)PRIN 2009.
In the temperature range +20 to −80 °C, the 31P NMR
spectra appear as AB2 multiplets indicating the magnetic
equivalence of the two phosphines PPh3, different from the
phosphite. These spectroscopic data support the proposed
formulation for the hydrazine complexes 9−11 but do not
allow us to assign them unambiguously a geometry in solution.
However, by comparison with the data of both azide complex
[OsCl{η1-NHC(H)C6H4-4-CH3}(CO)(PPh3)2{P(OEt)3}]-
BPh4 (8b), whose structure is known, and aryldiazene
derivatives [OsCl(CO)(ArNNH)(PPh3)2L]BPh4 (12, 13),
mer geometry VII (Scheme 7) may plausibly be proposed for
the hydrazine complexes.
Thanks also go to Mrs. Daniela Baldan for technical assistance.
DEDICATION
■
J.C. dedicates this publication to Prof. Antonio Sousa (USC,
Galicia, Spain) In Memoriam.
REFERENCES
■
(1) (a) The Chemistry of the Azido Group; Patai, S., Ed.; Interscience:
New York, 1971. (b) Azides and Nitrenes: Reactivity and Utility,
Scriven, E. F. V., Ed.; Academic: New York, 1984.
(2) (a) Cenini, S.; La Monica, G. Inorg. Chim. Acta 1976, 18, 279−
293. (b) Nugent, W. A.; Haymore, B. L. Coord. Chem. Rev. 1980, 31,
123−175. (c) Nugent, W. A.; Mayer, J. M. Metal-Ligand Multiple
Bonds; John Wiley & Sons: New York, 1988. (d) Wigley, D. E. Prog.
Inorg. Chem. 1994, 42, 239−482.
The IR spectra of aryldiazene derivatives [OsCl(CO)(ArN
NH)(PPh3)2L]BPh4 (12, 13) show the characteristic νCO at
1982−1969 cm−1, but no bands attributable to the aryldiazene
group were observed. However, its presence is confirmed by
(3) (a) Fortman, G. C.; Captain, B.; Hoff, C. D. Organometallics
2009, 28, 3587−3590. (b) Heyduk, A. F.; Blackmore, K. J.; Ketterer,
N. A.; Ziller, J. W. Inorg. Chem. 2005, 44, 468−470. (c) Brown, S. D.;
Betley, T. A.; Peters, J. C. J. Am. Chem. Soc. 2003, 125, 322−323.
(d) Jenkins, D. M.; Betley, T. A.; Peters, J. C. J. Am. Chem. Soc. 2002,
124, 11238−11239. (e) Guillemot, G.; Solari, E.; Floriani, C.; Rizzoli,
C. Organometallics 2001, 20, 607−615. (f) Barloy, L.; Gauvin, R. M.;
Osborn, J. A.; Sizun, C.; Graff, R.; Kyritsakas, N. Eur. J. Inorg. Chem.
2001, 1699−1707. (g) Johnson, C. E.; Trogler, W. C. Inorg. Chem.
1982, 21, 427−429. (h) Cui, C.; Roesky, H. W.; Schmidt, H.-G.;
Noltemeyer, M. Angew. Chem., Int. Ed. 2000, 39, 4531−4533.
(4) (a) Danopoulos, A. A.; Hay-Motherwell, R. S.; Wilkinson, G.;
Cafferkey, S. M.; Sweet, T. K. N.; Hursthouse, M. B. J. Chem. Soc.,
Dalton Trans. 1997, 3177−3184. (b) Meyer, K. E.; Walsh, P. J.;
Bergman, R. G. J. Am. Chem. Soc. 1995, 117, 974−985. (c) Michelman,
R. I.; Bergman, R. G.; Andersen, R. A. Organometallics 1993, 12,
2741−2751. (d) Hillhouse, G. L.; Haymore, B. L. J. Am. Chem. Soc.
1982, 104, 1537−1548. (e) Hillhouse, G. L.; Bercaw, J. E.
Organometallics 1982, 1, 1025−1029. (f) Antonelli, D. M.; Schaefer,
W. P.; Parkin, G.; Bercaw, J. E. J. Organomet. Chem. 1993, 462, 213−
220. (g) Gambarotta, S.; Chiesi-Villa, A.; Guastini, C. J. Organomet.
Chem. 1984, 270, C49−C52. (h) Hillhouse, G. L.; Goeden, G. V.;
Haymore, B. L. Inorg. Chem. 1982, 21, 2064−2071.
1
the H NMR spectra, which show a slightly broad doublet at
12.46−12.11 ppm, attributed to the NH diazene proton.
1
Support for this attribution also comes from the H spectrum
of the 15N-labeled complex [OsCl(CO)(C6H5N NH)-
15
(PPh3)2{P(OEt)3}]-BPh4 (12b1), which shows a doublet of
doublets centered at the same chemical shift of 12b, due to
15
31
1
15N
coupling with both the N and the P of one phosphine (J H
31P
31P
1
1
= 65.11, J H = 12.7 Hz). The J H values of the other
phosphine was very low and was not observed. In the
temperature range +20 to −80 °C, the 31P NMR spectrum is
an AB2X multiplet (X = 15N) simulable with the parameters
reported in the Experimental Section. The high values of J
compared with J
C6H5N NH is in a trans position with respect to the
phosphite P(OR)3. On the basis of these data, mer geometry
VIII may plausibly be proposed for the aryldiazene derivatives.
31PA15
N
31PB15
N
suggest that the aryldiazene
15
CONCLUSIONS
■
In this report we demonstrate that the mixed-ligand fragment
[OsCl(CO)(PPh3)2{P(OR)3}]+ allows us to prepare unprece-
dented organic azide complexes of osmium [OsCl(η1-N3R)-
(CO)(PPh3)2{P(OR)3}]BPh4. The spectroscopic data suggest
the η1-diazoamino coordination mode of the azide ligand. The
imine complex [OsCl{η1-NHC(H)C6H4-4-CH3}(CO)-
(PPh3)2{P(OR)3}]BPh4 was also prepared from the benzyla-
zide derivative. In addition, the fragment [OsCl(CO)-
(PPh3)2{P(OR)3}]+ can stabilize both hydrazine [OsCl-
(RNHNH2)(CO)(PPh3)2{P(OR)3}]BPh4 and aryldiazene
derivatives [OsCl(C6H5NNH)(CO)(PPh3)2{P(OR)3}]-
BPh4.
(5) (a) Fickes, M. G.; Davis, W. M.; Cummins, C. C. J. Am. Chem.
Soc. 1995, 117, 6384−6385. (b) Proulx, G.; Bergman, R. G.
Organometallics 1996, 15, 684−692. (c) Guillemot, G.; Solari, E.;
Floriani, C.; Rizzoli, C. Organometallics 2001, 20, 607−615.
(d) Mankad, N. P.; Muller, P.; Peters, J. C. J. Am. Chem. Soc. 2010,
̈
132, 4083−4085.
(6) (a) Barz, M.; Herdtweck, E.; Thiel, W. R. Angew. Chem., Int. Ed.
1998, 37, 2262−2265. (b) Dias, H. V. R.; Polach, S. A.; Goh, S.-K.;
Archibong, E. F.; Marynick, D. S. Inorg. Chem. 2000, 39, 3894−3901.
(c) Brotherton, W. S.; Guha, P. M.; Phan, M.; Clark, R. J.; Shatruk, M.;
Zhu, L. Dalton Trans. 2011, 40, 3655−3665.
́
(7) Albertin, G.; Antoniutti, S.; Baldan, D.; Castro, J.; Garcia-Fontan,
S. Inorg. Chem. 2008, 47, 742−748.
(8) (a) Waterman, R.; Hillhouse, G. L. J. Am. Chem. Soc. 2008, 130,
12628−12629. (b) Hanna, T. A.; Baranger, A. M.; Bergman, R. G.
Angew. Chem., Int. Ed. Engl. 1996, 35, 653−655.
ASSOCIATED CONTENT
■
S
* Supporting Information
(9) For azide cycloaddition see: (a) Lamberti, M.; Fortman, G. C.;
Poater, A.; Broggi, J.; Slawin, A. M. Z.; Cavallo, L.; Nolan, S. P.
Organometallics 2012, 31, 756−767. (b) Zhang, L.; Chen, X.; Xue, P.;
Sun, H. H. Y.; Williams, I. D.; Sharpless, K. B.; Fokin, V. V.; Jia, G. J.
Am. Chem. Soc. 2005, 127, 15998−15999. (c) Tornøe, C. W.;
Crystallographic data for compounds 2b and 8b (cif);
spectroscopic NMR and IR data for the labeled 5b1 and
unlabeled 5b compound (Figure S1−S2, pdf). This material is
available free of charge via the Internet at http://pubs.acs.org.
I
dx.doi.org/10.1021/ic302483e | Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
Christensen, C.; Meldal, M. J. Org. Chem. 2002, 67, 3057−3064.
(d) Rostovtsev, V. V.; Green, L. G.; Fokin, V. V.; Sharpless, K. B.
Angew. Chem., Int. Ed. 2002, 41, 2596−2599.
(28) Albertin, G.; Antoniutti, S.; Castro, J. Organometallics 2010, 29,
3808−3816.
(29) A search in the CCDC, CSD updated Feb. 2012 gives 69
octahedral Os compounds containing chloride and carbonyl as
mutually trans ligands. The mean value for the Os−Cl distance is
2.438 Å, and for the Os−C bond distance, it is 1.886 Å.
(30) Bell, A. G.; Kozminski, W.; Linden, A.; von Philipsborn, W.
Organometallics 1996, 15, 3124−3135.
(10) (a) Albertin, G.; Antoniutti, S.; Bacchi, A.; Bordignon, E.;
Busatto, F.; Pelizzi, G. Inorg. Chem. 1997, 36, 1296−1305. (b) Albertin,
G.; Antoniutti, S.; Bacchi, A.; Ballico, G. B.; Bordignon, E.; Pelizzi, G.;
Ranieri, M.; Ugo, P. Inorg. Chem. 2000, 39, 3265−3279. (c) Albertin,
G.; Antoniutti, S.; Bacchi, A.; Bordignon, E.; Miani, F.; Pelizzi, G.
Inorg. Chem. 2000, 39, 3283−3293. (d) Albertin, G.; Antoniutti, S.;
Bordignon, E.; Perinello, G. J. Organomet. Chem. 2001, 625, 217−230.
(e) Albertin, G.; Antoniutti, S.; Bordignon, E.; Visentin, E. Inorg.
Chem. 2001, 40, 5465−5467. (f) Albertin, G.; Antoniutti, S.; Bacchi,
A.; Bordignon, E.; Giorgi, M. T.; Pelizzi, G. Angew. Chem., Int. Ed.
2002, 41, 2192−2194. (g) Albertin, G.; Antoniutti, S.; Giorgi, M. T.
Eur. J. Inorg. Chem. 2003, 2855−2866. (h) Albertin, G.; Antoniutti, S.;
Bredariol, F. J. Organomet. Chem. 2003, 679, 208−219. (i) Albertin, G.;
Antoniutti, S.; Bacchi, A.; Fregolent, B.; Pelizzi, G. Eur. J. Inorg. Chem.
2004, 1922−1938. (j) Albertin, G.; Antoniutti, S.; Bravo, J.; Castro, J.;
(31) Albertin, G.; Antoniutti, S.; Bacchi, A.; Bortoluzzi, M.; Pelizzi,
G.; Zanardo, G. Organometallics 2006, 25, 4235−4237.
́
(32) Esteruelas, M. A.; García-Yebra, C.; Olivan, M.; Onate, E.;
̃
Tajada, M. A. Organometallics 2002, 21, 1311−1314.
(33) Betley, T. A.; Qian, B. A.; Peters, J. C. Inorg. Chem. 2008, 47,
11570−11582.
(34) While azide complexes [OsCl(η1 -N3 R)(CO)
(PPh3)2{P(OEt)3}]BPh4 are stable and isolable, the related ones
containing P(OMe)3 instead of P(OEt)3 are rather unstable in solution
and, even after crystallization, always give impure solid samples.
Complexes 5a, 5b, and 5c are therefore not reported.
́ ̀
Garcia-Fontan, S.; Marín, M. C.; Noe, M. Eur. J. Inorg. Chem. 2006,
3451−3462. (k) Albertin, G.; Antoniutti, S.; Bacchi, A.; Celebrin, A.;
Pelizzi, G.; Zanardo, G. Dalton Trans. 2007, 661−668.
(35) Geary, W. J. Coord. Chem. Rev. 1971, 7, 81−172.
(36) (a) Reed, A. E.; Curtiss, L. A.; Weinhold, F. Chem. Rev. 1988,
88, 899−926. (b) Curtiss, L. A.; Raghavachari, K.; Trucks, G. W.;
Pople, J. A. J. Chem. Phys. 1991, 94, 7221−7230.
(11) (a) Albertin, G.; Antoniutti, S.; Bacchi, A.; Bordignon, E.;
Pelizzi, G.; Ugo, P. Inorg. Chem. 1996, 35, 6245−6253. (b) Albertin,
G.; Antoniutti, S.; Bacchi, A.; Bordignon, E.; Dolcetti, P. M.; Pelizzi, G.
J. Chem. Soc., Dalton Trans. 1997, 4435−4444. (c) Albertin, G.;
Antoniutti, S.; Bordignon, E.; Pattaro, S. J. Chem. Soc., Dalton Trans.
1997, 4445−4453. (d) Albertin, G.; Antoniutti, S.; Bacchi, A.;
Bergamo, M.; Bordignon, E.; Pelizzi, G. Inorg. Chem. 1998, 37,
479−489. (e) Albertin, G.; Antoniutti, S.; Bacchi, A.; Barbera, D.;
Bordignon, E.; Pelizzi, G.; Ugo, P. Inorg. Chem. 1998, 37, 5602−5610.
(f) Albertin, G.; Antoniutti, S.; Bordignon, E.; Carrera, B. Inorg. Chem.
2000, 39, 4646−4650. (g) Albertin, G.; Antoniutti, S.; Bacchi, A.;
Boato, M.; Pelizzi, G. J. Chem. Soc., Dalton Trans. 2002, 3313−3320.
(h) Albertin, G.; Antoniutti, S.; Bacchi, A.; D’Este, C.; Pelizzi, G. Inorg.
Chem. 2004, 43, 1336−1349. (i) Albertin, G.; Antoniutti, S.;
(37) (a) Harman, W. D.; Taube, H. Inorg. Chem. 1988, 27, 3261−
3262. (b) Esteruelas, M. A.; Lahoz, F. J.; Lopez, A. M.; Onate, E.; Oro,
̃
L. A. Organometallics 1995, 14, 2496−2500. (c) Bustelo, F.; Jimenez-
Tenorio, M.; Puerta, M. C.; Valerga, P. J. Chem. Soc., Dalton Trans.
1999, 2399−2404. (d) Albertin, G.; Antoniuttti, S.; Castro, J. J.
Organomet. Chem. 2010, 695, 574−579.
(38) Rickard, C. E. F.; Roper, W. R.; Williamson, A.; Wright, L. J. J.
Organomet. Chem. 2004, 689, 1609−1616.
(39) Esteruelas, M. A.; Lopez, A. M.; Onate, E.; Royo, E.
́
̃
Organometallics 2004, 23, 5633−5636.
(40) Castarlenas, R.; Esteruelas, M. A.; Onate, E. Organometallics
̃
2000, 19, 5454−5463.
(41) Gunnoe, T. B.; White, P. S.; Templeton, J. L. J. Am. Chem. Soc.
1996, 118, 6916−6923.
́
Bortoluzzi, M.; Castro-Fojo, J.; Garcia-Fontan, S. Inorg. Chem. 2004,
43, 4511−4522. (j) Albertin, G.; Antoniutti, S.; Bacchi, A.; De Marchi,
F.; Pelizzi, G. Inorg. Chem. 2005, 44, 8947−8954. (k) Albertin, G.;
(42) Tu, X.; Truong, H.; Alster, E.; Munoz-Castro, A.; Arratia-Per
́
ez,
̃
R.; Nichol, G. S.; Zheng, Z. Chem.Eur. J. 2011, 17, 580−5870.
́
Antoniutti, S.; Bedin, M.; Castro, J.; Garcia-Fontan, S. Inorg. Chem.
(43) Russell, S. K.; Lobkovsky, E.; Chirik, P. J. J. Am. Chem. Soc.
2009, 131, 36−37.
2006, 45, 3816−3825. (l) Albertin, G.; Antoniutti, S.; Castro, J.;
Paganelli, S. J. Organomet. Chem. 2010, 695, 2142−2152. (m) Albertin,
G.; Antoniutti, S.; Castro, J. J. Organomet. Chem. 2012, 697, 6−14.
(12) Alvarez, S. G.; Alvarez, M. T. Synthesis 1997, 413−414.
(13) Lindsay, R. O.; Allen, C. F. H. Org. Synth. 1955, 3, 710−711.
(14) Vogel, A. I. In Practical Organic Chemistry, 3rd ed.; Longmans,
Green and Co.: New York, 1956.
(44) The 1H NMR spectra of the oxidation product of
[OsCl(NH2NH2)(CO)(PPh3)2{P(OEt)3}]BPh4 (9b) show two
slightly broad multiplets at 14.98 and at 14.58 ppm, attributable to
the two NH protons of the 1,2-diazene ligand of the [OsCl(η1-NH
−
NH)(CO)(PPh3)2{P(OEt)3}]+BPh4 derivative.
(45) Chen, T.-Y.; Ponce, A.; Rheingold, A. L.; Hillhouse, G. L.
Angew. Chem., Int. Ed. 1994, 33, 657−659.
(15) Balacco, G. http://www.inmr.net/ (accessed Nov 2012).
(16) Elliott, G. P.; McAuley, N. M.; Roper, W. R. Inorg. Synth. 1989,
26, 184−185.
(17) SMART, Version 5.054, Instrument control and data collection
software; Bruker Analytical X-ray Systems Inc., Madison, Wisconsin,
USA, 1997.
(18) SAINT, Version 6.01, Data Integration software package; Bruker
Analytical X-ray Systems Inc.: Madison, Wisconsin, USA, 1997.
(19) Sheldrick, G. M. SADABS. An empirical absorption correction
(46) (a) Sutton, D. Chem. Rev. 1993, 93, 995−1022. (b) Kisch, H.;
Holzmeir, P. Adv. Organomet. Chem. 1992, 34, 67−109. (c) Zollinger,
H. Diazo Chemistry II; VCH: Weinheim, Germany, 1995.
(47) (a) Davis, L. C. Arch. Biochem. Biophys. 1980, 204, 270−276.
(b) Burgess, B. K.; Wherland, S.; Newton, W. E.; Stiefel, E. I.
Biochemistry 1981, 20, 5140−5146.
(48) (a) Heaton, B. T.; Jacob, C.; Page, P. Coord. Chem. Rev. 1996,
154, 193−229. (b) Crossland, J. L.; Zakharov, L. N.; Tyler, D. R. Inorg.
Chem. 2007, 46, 10476−10478. (c) Field, L. D.; Li, H. L.; Dalgarno, S.
J. Inorg. Chem. 2010, 49, 6214−6221 , and references therein..
program for area detector data; University of Gottingen: Germany,
̈
1996.
(20) Altomare, A.; Cascarano, G.; Giacovazzo, C.; Gagliardi, A.;
Burla, M. C.; Polidori, G.; Cavalli, M. J. Appl. Cryst. 1994, 27, 435−
435.
(21) Farrugia, L. J. J. Appl. Crystallogr. 1999, 32, 837−838.
(22) Sheldrick, G. M. Acta Crystallogr. 2008, A64, 112−122.
(23) McArdle, P. J. Appl. Cryst. 1995, 28, 65−65.
(24) Vaska, L. J. Am. Chem. Soc. 1964, 86, 1943−1950.
(25) Crabtree, R. H.; Lavin, M.; Bonneviot, L. J. Am. Chem. Soc.
1986, 108, 4032−4037.
(26) Kubas, G. J. Metal Dihydrogen and σ-Bond Complexes; Kluwer
Academic/Plenum Publishers: New York, 2001.
(27) Farrugia, L. J. J. Appl. Crystallogr. 1997, 30, 565−566.
J
dx.doi.org/10.1021/ic302483e | Inorg. Chem. XXXX, XXX, XXX−XXX