Synthesis, structures, and reactivity of ruthenium(II) nitrosyl tri- And dialkyl complexes

Article abstract of DOI:10.1021/om900598j

Treatment of Ru(dtbpy)(NO)Cl₃ (dtbpy = 4,4′-di-tert-butyl- 2,2′-bipyridyl) (1) with Me₃SiCH₂MgCl afforded the trialkyl compound mer-Ru(dtbpy)(NO)(CH₂SiMe₃)₃ (2), which exhibits v_NO

Full text of DOI:10.1021/om900598j

5794 Organometallics 2009, 28, 5794–5801
DOI: 10.1021/om900598j
Synthesis, Structures, and Reactivity of Ruthenium(II) Nitrosyl Tri- and
Dialkyl Complexes
Ka-Wang Chan, Enrique Kwan Huang, Ian D. Williams, and Wa-Hung Leung*
Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay,
Kowloon, Hong Kong, People’s Republic of China
Received July 9, 2009
Treatment of Ru(dtbpy)(NO)Cl3 (dtbpy=4,40-di-tert-butyl-2,20-bipyridyl) (1) with Me3SiCH2MgCl
afforded the trialkyl compound mer-Ru(dtbpy)(NO)(CH2SiMe3)3 (2), which exhibits νNO at 1741 cm-1
in the IR spectrum. The solid-state structure of 2 shows a mer arrangement for the three alkyl groups and
that the nitrosyl is trans to dtbpy. Protonation of 2 with HX afforded the dialkyl compounds cis,
cis-Ru(dtbpy)(CH2SiMe3)(NO)X (X=Cl (3), OTs (4)), in which X is trans to an alkyl group. Treatment
of 3 with AgOTf (OTf-=triflate) afforded cis,cis-Ru(dtbpy)(CH2SiMe3)2(NO)(OTf) (5), which reacted
with amines RNH2 to give the adducts cis,cis-[Ru(dtbpy)(CH2SiMe3)2(NO)(NH2R)][OTf] (R=meistyl
(6), 4-tol (7)). Substitution of 5 with NaOR led to the isolation of cis,trans-Ru(dtbpy)(CH2SiMe3)2-
(NO)(OR) (R=Ph (8), SiMe3 (9), SiPh3 (10)), in which the nitrosyl is trans to OR-, whereas that with
NaSR gave cis,cis-Ru(dtbpy)(CH2SiMe3)2(NO)(SR) (R=2,6-Me2C6H4 (11), SiPh3 (12)). Treatment of 5
with K[OsO3N] afforded the bimetallic complex cis,cis-Ru(dtbpy)(CH2SiMe3)2(NO)(NOsO3) (13),
containing an unsymmetrical Os(VIII)tN-Ru(II) bridge. The crystal structures of 2-5, 7-10, 12,
and 13 have been determined.
Introduction
diboron reagents under mild conditions.8 It is believed that the
Ir(bpy)-catalyzed borylation involves the oxidative addition of
arene C-H bonds with Ir(III) boryl intermediates.9 This
suggests that electron-donating bpy can serve as a good
spectator ligand for high-valent transition-metal alkyl/aryl
complexes. Recently, we have isolated Ir and Rh alkyl and aryl
compounds with 4,40-di-tert-butyl-2,20-bipyridyl (dtbpy) that
were found to exhibit interesting reactivity, e.g., C-H activa-
tion and C-Si cleavage.10 This prompted us to synthesize
analogous Ru(dtbpy) trialkyl compounds and investigate their
organometallic chemistry.
A common method to synthesize Ru σ-alkyl compounds
involves transmetalation of Ru chloride compounds with
alkylating agents such as alkyl lithium and Grignard re-
agents. Young and co-workers synthesized the dialkyl com-
pounds Ru(dtbpy)2R2 (R = Me, Et, CH2-cyclo-C6H11,
CH2SiMe2CHdCH2, CH2SiMe3, CH2SiMe2Ph, CH2CMe2-
Ph) from Ru(dtbpy)2Cl2 and the corresponding Grignard
reagents.3 However, Ru(dtbpy)Cl3, which is a precursor to
Ru trialkyl compounds, is unknown. We then turned our
attention to Ru(NO)(dtbpy)R3 because Ru(bpy) nitrosyl
complexes are usually photolabile and the nitrosyl ligand
Ruthenium complexes with polypyridyl ligands, notably
2,20-bipyridyl (bpy), are of interest due to their applications
to redox and photochemical catalysis.1 While the coordina-
tion chemistry of Ru(bpy)n (n = 1, 2, 3) compounds has
been studied extensively, Ru(bpy) compounds with σ-alkyl
ligands are rather uncommon.2,3 To our knowledge, Ru-
(bpy) trialkyl compounds have not been synthesized to date,
although Ru poly-alkyl/aryl compounds such as Ru2R6 (R=
CH2CMe3, CH2SiMe3),4 RuR4 (R = o-tol, mesityl),5
[Li(tmed)2][RuMe6],6 and [Ru(N)RnX4-n]- (R=Me, CH2Si-
Me3)7 are known.
Our interest in bpy-supported transition-metal alkyl com-
pounds is stimulated by recent reports that Ir(bpy) compounds
can catalyze selective borylation of arenes with borane and
*To whom correspondence should be address. E-mail: chleung@ust.hk.
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r
pubs.acs.org/Organometallics
Published on Web 09/10/2009
2009 American Chemical Society

Article
Organometallics, Vol. 28, No. 19, 2009 5795
can be easily removed by photolysis.11 In addition, photo-
active Ru nitrosyl compounds are important in their own
right because they can function as NO donors under bio-
logical conditions.12 Although organometallic nitrosyl com-
pounds are well documented,13 Ru nitrosyl compounds with
σ-alkyl ligands are rather rare.14 Herein, we describe the
synthesis and structure of the first Ru nitrosyl trialkyl
compounds, mer-Ru(dtbpy)(NO)(CH2SiMe3)3. The proton-
ation of mer-Ru(dtbpy)(NO)(CH2SiMe)3 with acids to give
dialkyl complexes has been studied. The synthesis and crystal
structures of Ru(dtbpy) dialkyl complexes with siloxide,
phenoxide, and thiolate ligands as well as a bimetallic nitrido-
bridged Ru(II)/Os(VIII) complex will also be reported.
Scheme 1. Syntheses of Ru(dtbpy) Tri- and Dialkyl Complexes
Experimental Section
General Considerations. All manipulations were carried out
under nitrogen by standard Schlenk techniques. Solvents were
purified, distilled, and degassed prior to use. NMR spectra were
recorded on a Varian Mercury 300 spectrometer operating at
300 and 282.4 MHz for 1H and 19F, respectively. Chemical shifts
(δ, ppm) were reported with reference to SiMe4 (1H) and
C6H5CF3 (19F). Infrared spectra were recorded on a Perkin-
Elmer 16 PC FT-IR spectrophotometer; mass spectra, on a
Finnigan TSQ 7000 spectrometer. Elemental analyses were
performed by Medac Ltd., Surrey, UK. Ru(NO)Cl3 xH2O
3
(Mþ - CH2SiMe3 þ 1). Despite several attempts, we have not
been able to obtain satisfactory elemental analysis (particularly the
carbon content). Nevertheless, this compound has been well
characterized by spectroscopic methods and X-ray diffraction.
Preparation of cis,cis-Ru(dtbpy)(CH2SiMe3)2(NO)Cl (3). To a
solution of 2 (138 mg, 0.21 mmol) in hexane (4 mL) was added
HCl (0.06 mL of a 3.5 M solution in Et2O, 0.21 mmol) at -78 °C,
and the mixture was stirred at room temperature for 3 h. The red
precipitate was collected, washed with hexane, and recrystal-
lized from CH2Cl2/Et2O/hexane to give reddish-brown crystals,
which were suitable for X-ray analysis. Yield: 109 mg (85%). 1H
NMR (300 MHz, C6D6): δ -0.11 (s, 9H, CH2SiMe3), 0.62 (d, J=
12.9 Hz, 2H, CH2SiMe3), 0.76 (s, 9H, CH2SiMe3), 0.85 (s, 9H, t-
Bu), 0.94 (s, 9H, t-Bu), 1.89 (d, J=12.9 Hz, 1H, CH2SiMe3), 2.06
(d, J = 9.4 Hz, 1H, CH2SiMe3), 2.84 (d, J = 9.4 Hz, 1H,
CH2SiMe3), 6.54 (d, J=7.9 Hz, 1H, H5), 6.72 (d, J=7.6 Hz,
1H, H5), 7.70 (s, 1H, H3), 7.80 (s, 1H, H3), 8.70 (d, J=6.2 Hz, 1H,
H6), 8.75 (d, J=5.9 Hz, 1H, H6). IR (KBr, cm-1): 1773 (νNO).
and 4,40-di-tert-butyl-2,20-bipyridyl (dtbpy) were obtained from
Strem and Aldrich Ltd., respectively. K[OsO3N] was synthe-
sized according to a literature method.15 A hydrogen atom
labeling scheme of the dtbpy ligand is shown in Scheme 1.
Preparation of Ru(dtbpy)(NO)Cl3 (1). To a solution of Ru-
(NO)Cl3 xH2O (200 mg, 0.78 mmol) in MeOH (2 mL) was added
3
dtbpy (210 mg, 0.78 mmol), and the mixture was heated at reflux for
1 h. The precipitate was collected and washed with methanol (3 ꢀ
2mL) andEt2O(3ꢀ 2 mL). Recrystallization from CH2Cl2/hexane
1
afforded a dark pink powder. Yield: 272 mg (69%). H NMR
(300 MHz, CD2Cl2): δ 1.49 (s, 18H, t-Bu), 7.78 (d, J=5.9 Hz, 2H,
H5), 8.22 (s, 2H, H3), 9.52 (d, J=6.2 Hz, 2H, H6). IR (KBr, cm-1):
1871 (νNO). MS (FAB): m/z 470 (Mþ - Cl). Anal. Calcd for
C18H24Cl3N3ORu 1/4CH2Cl2: C, 41.57; H, 4.69; N, 7.97. Found:
3
C, 42.06; H, 4.17; N, 7.42.
Preparation of mer-Ru(dtbpy)(NO)(CH2SiMe3)3 (2). To a
suspension of 1 (100 mg, 0.20 mmol) in tetrahydrofuran (THF)
(6 mL) was added Me3SiCH2MgCl (0.54 mL of a 1.3 M solution in
THF, 0.70 mmol) at -78 °C. The mixture was stirred at room
temperature for 5 h, and the volatiles were removed in vacuo. The
residue was extracted with hexane. Concentration and cooling at
-4 °C gave deep red crystals, which were suitable for X-ray
Anal. Calcd for C26H46ClN3ORuSi2 3/4CH2Cl2: C, 47.73; H,
3
7.12; N, 6.25. Found: C, 47.84; H, 7.19; N, 6.34.
Preparation of cis,cis-Ru(dtbpy)(CH2SiMe3)2(NO)(OTs) (OTs=
tosylate) (4). To a solution of 2 (100 mg, 0.15 mmol) in hexane was
added p-toluenesulfonic acid (24 mg, 0.15 mmol) at -78 °C, and the
mixture was stirred at room temperature for 24 h. The purple
precipitate was collected and washed with Et2O and hexane.
Recrystallization from CH2Cl2/Et2O/hexane afforded purple crys-
tals that were suitable for X-ray analysis. Yield: 75 mg (72%). 1H
NMR (300 MHz, C6D6): δ -0.11 (s, 9H, CH2SiMe3), 0.61 (s, 9H,
CH2SiMe3), 0.85 (s, 9H, t-Bu), 1.03 (s, 9H, t-Bu), 1.29 (d, J=
12.6 Hz, 1H, CH2SiMe3), 1.73 (d, J=12.6 Hz, 1H, CH2SiMe3), 1.83
(s, 3H, Me), 1.96 (d, J=10.0 Hz, 1H, CH2SiMe3), 2.06 (d, J=
10.0 Hz, 1H, CH2SiMe3), 6.57 (d, J=5.6 Hz, 1H, H5), 6.67 (d, J=
7.9 Hz, 2H, Ho of tosyl), 6.96 (d, J=5.9 Hz, 1H, H5), 7.79 (s, 1H,
H3), 7.88 (d, J=7.9 Hz, 2H, Hm of tosyl), 7.92 (s, 1H, H3), 8.68 (d,
J=6.2 Hz, 1H, H6), 9.14 (d, J=5.9 Hz, 1H, H6). IR (KBr, cm-1):
1803 (νNO). Anal. Calcd for C33H53N3O4RuSSi2: C, 53.20; H, 7.17;
N, 5.64. Found: C, 53.21; H, 7.53; N, 5.48.
1
analysis. Yield: 84 mg (65%). H NMR (300 MHz, C6D6): δ
-0.55 (d, J=12.5 Hz, 2H, CH2SiMe3), 0.02 (s, 18H, CH2SiMe3),
0.71 (s, 9H, CH2SiMe3), 0.85 (s, 9H, t-Bu), 1.01 (s, 9H, t-Bu), 1.24
(d, J=12.5 Hz, 2H, CH2SiMe3), 1.59 (s, 2H, CH2SiMe3), 6.49 (d,
J=6.2 Hz, 1H, H5), 6.66 (d, J=5.7 Hz, 1H, H5), 7.81 (s, 1H, H3),
7.96 (s, 1H, H3), 8.60 (d, J=6.2 Hz, 1H, H6), 8.97 (d, J=5.7 Hz,
1H, H6). IR (KBr, cm-1): 1741 (νNO). MS (FAB): m/z 574
(11) (a) Callahan, R. W.; Meyer, T. J. Inorg. Chem. 1977, 16, 574.
(b) Sauaia, M. G.; Oliveira, F. S.; Tedesco, A. C.; da Silva, R. S. Inorg. Chim.
Acta 2003, 355, 191. (c) Sauaia, M. G.; de Lima, R. G.; Tedesco, A. C.;
da Silva, R. S. J. Am. Chem. Soc. 2003, 125, 14718.
(12) (a) Rose, M. J.; Mascharak, P. K. Coord. Chem. Rev. 2008, 252,
2093. (b) Tfouni, E.; Krieger, M.; McGarvey, B. R.; Franco, D. W. Coord.
Chem. Rev. 2003, 236, 57.
(13) Hayton, T. W.; Legzdins, P.; Sharp, W. B. Chem. Rev. 2001, 101,
935.
(14) (a) Chang, J.; Seidler, M. D.; Bergman, R. G. J. Am. Chem. Soc.
1989, 111, 3258. (b) Chang, J.; Bergman, R. G. J. Am. Chem. Soc. 1987,
109, 4298. (c) Seidler, M. D.; Bergman, R. G. J. Am. Chem. Soc. 1984,
106, 6110. (d) Hodge, S. J.; Wang, L.-S.; Khan, M. A.; Young, V. G., Jr;
Richter-Addo, G. B. Chem. Commun. 1996, 2283.
Preparation of cis,cis-Ru(dtbpy)(CH2SiMe3)2(NO)(OTf) (5).
To a solution of 3 (172 mg, 0.28 mmol) in CH2Cl2 (4 mL) was
added AgOTf (75 mg, 0.29 mmol). The mixture was stirred at
room temperature for 5 h and filtered and evaporated to
dryness. Recrystallization from hexane at -4 °C gave purple
crystals that were suitable for X-ray analysis. Yield: 162 mg
(15) Clifford, A. F.; Kobayashi, C. S. Inorg. Synth. 1960, 6, 204.

5796 Organometallics, Vol. 28, No. 19, 2009
Chan et al.
(80%). 1H NMR (300 MHz, C6D6): δ -0.20 (s, 9H, CH2SiMe3),
0.61 (s, 9H, CH2SiMe3), 0.77 (d, J=12.9 Hz, 2H, CH2SiMe3),
0.86 (s, 9H, t-Bu), 0.95 (d, J=12.9 Hz, 2H, CH2SiMe3), 1.01
(s, 9H, t-Bu), 1.83 (d, J=10.0 Hz, 2H, CH2SiMe3), 1.95 (d, J=
10.0 Hz, 2H, CH2SiMe3), 6.59 (d, J=5.3 Hz, 1H, H5), 6.91 (d, J=
7.6 Hz, 1H, H5), 7.83 (s, 1H, H3), 7.96 (s, 1H, H3), 8.58 (d, J=
6.2 Hz, 1H, H6), 8.80 (d, J = 5.3 Hz, 1H, H6). 19F NMR
(282 MHz, C6D6): δ -78.24 (OTf). IR (KBr, cm-1): 1809
CH2SiMe3), 2.45 (d, J=13.2 Hz, 2H, CH2SiMe3), 6.82 (dd, J=
7.7 and 1.7 Hz, 2H, H5), 7.01-7.07 (m, 9H, phenyl), 7.41 (dd, J=
7.4 and 1.9 Hz, 6H, Ph), 7.59 (d, J=1.7 Hz, 2H, H3), 8.89 (d, J=
5.5 Hz, 2H, H6). IR (KBr, cm-1): 1766 (νNO). Anal. Calcd for
C44H61N3O2RuSi3: C, 62.22; H, 7.24; N, 4.95. Found: C, 62.15; H,
7.26; N, 4.86.
Preparation of cis,cis-Ru(dtbpy)(CH2SiMe3)2(NO)(SC6H3-
Me2-2,6) (11). To
a solution of 2,6-dimethylbenzenethiol
(7.6 mg, 0.055 mmol) in THF was added NaH (5 mg, 0.13 mmol,
60% in mineral oil). The reaction mixture was stirred at room
temperature for 30 min, and a solution of 5 (40 mg, 0.055 mmol) in
THF (10 mL) was added at 0 °C. The resulting mixture was stirred
at room temperature for 12 h. The solvent was removed in vacuo,
and the residue was extracted with Et2O/hexane (1:1, v/v). Con-
centration and cooling at -4 °C gave an orange powder. Yield:
27 mg (72%). 1H NMR (300 MHz, C6D6): δ 0.13 (s, 9H,
CH2SiMe3), 0.22 (d, J= 12.6 Hz, 1H, CH2SiMe3), 0.80 (s, 9H,
CH2SiMe3), 0.90 (s, 9H, t-Bu), 0.99 (s, 9H, t-Bu), 1.67 (d, J=12.8
Hz, 1H, CH2SiMe3), 1.85 (d, J=9.6 Hz, 1H, CH2SiMe3), 1.94 (br s,
6H, Me), 2.42 (d, J=9.6 Hz, 1H, CH2SiMe3), 6.36 (d, J=1.8 Hz,
1H, H5), 6.39 (d, J=1.9 Hz, 1H, H5), 6.48 (d, J=6.6 Hz, 2H,
phenyl),7.01(t,J=6.6 Hz, 1H, phenyl), 7.32 (d, J=1.5 Hz, 1H, H3),
7.54 (d, J=1.8 Hz, 1H, H3), 8.43 (d, J=6.0 Hz, 1H, H6), 8.66 (d,
J=6.3 Hz, 1H, H6). IR (KBr, cm-1): 1760 (νNO). Anal. Calcd for
C34H55N3ORuSSi2: C, 57.43; H, 7.80; N, 5.91. Found: C, 57.53; H,
8.29; N, 6.11.
Preparation of cis,cis-Ru(dtbpy)(CH2SiMe3)2(NO)(SSiPh3)
(12). This compound was prepared similarly to complex 11
using Ph3SiSH in place of 2,6-dimethylbenzenethiol. Yield:
38 mg (80%). 1H NMR (300 MHz, C6D6): δ -0.21 (s, 9H,
CH2SiMe3), -0.01 (d, J=12.6 Hz, 1H, CH2SiMe3), 0.79 (s, 9H,
CH2SiMe3), 0.92 (s, 9H, t-Bu), 0.95 (s, 9H, t-Bu), 1.65 (d, J=
12.6 Hz, 1H, CH2SiMe3), 1.88 (d, J=9.6 Hz, 1H, CH2SiMe3),
2.48 (d, J=9.6 Hz, 1H, CH2SiMe3), 6.46 (d, J=5.8 Hz, 1H, H5),
6.51 (d, J=6.0 Hz, 1H, H5), 7.05 (m, 9H, phenyl), 7.41 (s, 1H,
H3), 7.43 (s, 1H, H3), 7.77 (m, 6H, phenyl), 8.03 (d, J=5.7 Hz,
1H, H6), 8.72 (d, J=6.3 Hz, 1H, H6). IR (KBr, cm-1): 1775
(νNO). Anal. Calcd for C27H46F3N3O4RuSSi2 0.5C6H14: C,
3
47.04; H, 6.97; N, 5.49. Found: C, 47.00; H, 7.15; N, 5.36.
Preparation of cis,cis-[Ru(dtbpy)(CH2SiMe3)2(NO)(NH2R)]-
[OTf] (R = 2,4,6-Me3C6H2 (6), 4-tol (7)). To a solution of
5 (40 mg, 0.055 mmol) in THF (10 mL) was added NH2R
(0.057 mmol), and the mixture was stirred at room temperature
for 3 h. The volatiles were removed in vacuo, and the residue
was washed with hexane. Recrystallization from CH2Cl2/
hexane at -30 °C gave a brown solid.
1
For 6: Yield: 28 mg (60%). H NMR (300 MHz, C6D6): δ
-0.21 (s, 9H, CH2SiMe3), 0.57 (s, 9H, CH2SiMe3), 0.78 (m, 3H,
NH2C6H2Me3 and CH2SiMe3), 0.91 (s, 9H, t-Bu), 1.06 (s, 9H,
t-Bu), 1.19 (d, J=13.0 Hz, 1H, CH2SiMe3), 1.79 (d, J=12.3 Hz,
1H, CH2SiMe3), 1.90 (s, 6H, NH2), 1.95 (d, J=13.1 Hz, 1H,
CH2SiMe3), 2.20 (s, 3H, Me), 6.63 (br s, 1H, H5), 6.73 (s, 2H, Hm
of p-tol), 6.90 (d, J=6.0 Hz, 1H, H5), 7.91 (br s, 1H, H3), 8.03
(br s, 1H, H3), 8.55 (d, J=6.0 Hz, 1H, H6), 8.72 (br s, 1H, H6).
19F NMR (282 MHz, C6D6): δ -78.13 (OTf). IR (KBr, cm-1):
1786 (νNO). Anal. Calcd for C36H59F3N4O4RuSSi2: C, 50.38; H,
6.93; N, 6.53. Found: C, 50.20; H, 7.37; N, 6.58.
For 7: Yield: 25 mg (54%). 1H NMR (300 MHz, C6D6):δ -0.32
(s, 9H, CH2SiMe3), 0.29 (s, 9H, CH2SiMe3), 0.55 (br s, 2H, NH2),
1.16 (s, 9H, t-Bu), 1.26 (s, 9H, t-Bu), 1.65 (m, 2H, CH2SiMe3),
1.75 (d, J=10.5 Hz, 1H, CH2SiMe3), 2.04 (s, 3H, Me), 4.78 (d, J=
10.5 Hz, 1H, CH2SiMe3), 6.02 (d, J=10.8 Hz, 1H, H5), 6.41 (d, J=
6.0 Hz, 1H, H5), 6.50 (d, J=8.4 Hz, 2H, Hm of p-tol), 6.65 (d, J=
8.3 Hz, 2H, Ho of p-tol), 7.61 (d, J=5.7 Hz, 1H, H6), 8.37 (s, 1H,
H3), 8.44 (s, 1H, H3), 8.54 (d, J=6.0 Hz, 1H, H6). 19F NMR (282
MHz, C6D6): δ -77.80 (OTf). IR (KBr, cm-1): 1779 (vNO). Anal.
(νNO). Anal. Calcd for C44H61N3ORuSSi3 1/2H2O: C, 60.44; H,
Calcd for C34H55F3N4O4RuSSi2 1/4CH2Cl2: C, 48.32; H, 6.58; N,
3
3
7.15; N, 4.81. Found: C, 60.44; H, 7.21; N, 4.64.
6.58. Found: C, 48.02; H, 6.51; N, 6.74.
Preparation of cis,cis-Ru(dtbpy)(CH2SiMe3)2(NO)(NOsO3)
(13). To a solution of 5 (50 mg, 0.07 mmol) in THF was added
KOsO3N (20 mg, 0.07 mmol) at -78 °C. The mixture was stirred
for 12 h at room temperature, and the volatiles were removed in
vacuo. The residue was washed with hexane and extracted with
toluene. Concentration and cooling at -4 °C gave red crystals
Preparation of cis,trans-Ru(dtbpy)(CH2SiMe3)2(NO)(OPh)
(8). To a solution of 5 (100 mg, 0.14 mmol) in THF was added
NaOPh (16 mg, 0.14 mmol) at -78 °C. The mixture was stirred
for 12 h at room temperature, and the volatiles were removed in
vacuo. The residue was washed with hexane and extracted with
toluene. Concentration and cooling at -4 °C gave orange
crystals that were suitable for X-ray analysis. Yield: 18 mg
(19%). 1H NMR (300 MHz, C6D6): δ 0.61 (s, 18H, CH2SiMe3),
0.95 (s, 18H, t-Bu), 2.11 (d, J=12.6 Hz, 2H, CH2SiMe3), 2.37
(d, J=12.6 Hz, 2H, CH2SiMe3), 5.82 (d, J=8.5 Hz, 2H, H5), 6.29
(d, J=7.0 Hz, 1H, OPh), 6.55 (t, J=7.3 Hz, 2H, phenyl), 6.69
(dd, J=5.9 and 2.0 Hz, 2H, phenyl), 7.50 (s, 2H, H3), 8.85 (d, J=
5.6 Hz, 2H, H6). IR (KBr, cm-1): 1771 (νNO). Anal. Calcd for
C32H51N3O2RuSi2: C, 57.62; H, 7.71; N, 6.30. Found: C, 57.21;
H, 7.98; N, 6.18.
1
that were suitable for X-ray analysis. Yield: 20 mg (35%). H
NMR (300 MHz, C6D6): δ -0.12 (s, 9H, CH2SiMe3), 0.29 (s,
2H, CH2SiMe3), 0.59 (s, 9H, CH2SiMe3), 0.78 (d, J=12.6 Hz,
1H, CH2SiMe3), 0.91 (s, 9H, t-Bu), 0.97 (s, 9H, t-Bu), 1.63 (d, J=
12.6 Hz, 1H, CH2SiMe3), 6.63 (dd, J=5.9 and 1.8 Hz, 1H, H5),
6.77 (dd, J=5.9 and 2.1 Hz, 1H, H5), 7.91 (d, J=1.8 Hz, 1H, H3),
7.98 (d, J=1.6 Hz, 1H, H3), 8.37 (d, J=5.7 Hz, 1H, H6), 8.44 (d,
J=5.7 Hz, 1H, H6). IR (KBr, cm-1): 1806 (νNO), 1030 (νOsN),
901, 886 (νOsO). Anal. Calcd for C26H46N4O4OsRuSi2: C, 37.80;
H, 5.61; N, 6.78. Found: C, 37.69; H, 5.60; N, 6.76.
Preparation of cis,trans-Ru(dtbpy)(CH2SiMe3)2(NO)(OSiR3)
(R=Me (9), Ph (10). To a solution of 5 (100 mg, 0.14 mmol) in
THF was added NaOSiR3 (0.14 mmol) at -78 °C. The mixture
was stirred for 12 h at room temperature, and the volatiles were
removed in vacuo. The residue was washed with hexane and was
then extracted with toluene. Concentration and cooling at -4 °C
gave orange crystals that were suitable for X-ray analysis.
X-ray Crystallography. Preliminary examinations and intensity
data collection were carried out on a Bruker SMART-APEX 1000
area-detector diffractometer using graphite-monochromated Mo
˚
KR radiation (λ=0.70173 A). The collected frames were processed
with the software SAINT.16 The data were corrected for absorp-
tion using the program SADABS.17 Structures were solved by
direct methods and refined by full-matrix least-squares on F2
using the SHELXTL software package.17 Unless stated otherwise,
non-hydrogen atoms were refined with anisotropic displacement
parameters. Carbon-bonded hydrogen atoms were included in
1
For 9: Yield: 64 mg (69%). H NMR (300 MHz, C6D6): δ
-0.35 (s, 9H, OSiMe3), 0.62 (s, 18H, CH2SiMe3), 0.95 (s, 18H,
t-Bu), 1.93 (d, J=13.2 Hz, 2H, CH2SiMe3), 2.10 (d, J=13.2 Hz,
2H, CH2SiMe3), 6.86 (dd, J=7.2 Hz and 1.8 Hz, 2H, H5), 7.84
(d, J=1.5 Hz, 2H, H3), 8.97 (d, J=2.9 Hz, 2H, H6). IR (KBr,
cm-1): 1768 (vNO) Anal. Calcd for C29H55N3O2RuSi3: C, 52.53;
H, 8.36; N, 6.34. Found: C, 52.08; H, 8.38; N, 6.61.
€
(16) Sheldrick, G. M. SADABS; University of Gottingen: Germany,
1997.
(17) Sheldrick, G. M. SHELXTL-Plus V5.1 Software Reference
For 10: Yield: 74 mg (61%). 1H NMR (300 MHz, C6D6): δ 0.55
(s, 18H, CH2SiMe3), 0.97 (s, 18H, t-Bu), 2.01 (d, J=13.2 Hz, 2H,
Manual; Bruker AXS Inc.: Madison, WI, 1997.

Article
Organometallics, Vol. 28, No. 19, 2009 5797
calculated positions and refined in the riding mode using
SHELXL97 default parameters. In 3, one of the t-Bu groups of
dtbpy was found to be disordered, and each of the carbon atoms
C(22), C(23), and C(24) was split into two sites with occupancies of
0.55 and 0.45. In 5, the fluorine atoms F(1), F(2), and F(3) of the
triflate ligand were found to be 50:50 disordered. In 7, the C(28) of
the p-tolNH2 ligand, C(37) of dtbpy, and F(1)-F(3) and O(2)-
O(4) atoms of the triflate counteranion were found to be 50:50
disordered. In 10, one of the t-Bu groups in dtbpy was found to be
disordered. Each of the carbon atoms C(42)-C(44), C(47), and
C(48) was split into two sites with occupancies of 0.75 and 0.25,
while C(46) was split into three sites with occupancies of 0.65, 0.25,
and 0.1.
Results and Discussion
Ruthenium Trialkyl Complex. Alkylation of the trichloride
compound Ru(dtbpy)(NO)Cl3 (1) with a variety of alkylat-
ing agents including alkyl lithium and Grignard reagents has
been attempted. In most cases, dark intractable materials
were formed. However, for the alkylation of 1 with Me3-
SiCH2MgCl, a red crystalline, hexane-soluble product was
obtained. Recrystallization from hexane afforded single
crystals identified as mer-Ru(dtbpy)(NO)(CH2SiMe3)3 (2)
in 65% yield. 2 is moderately air stable in the solid state, but
air sensitive in solutions. The 1H NMR spectrum showed two
singlets at δ 1.01 and 1.81 due to the tert-butyl groups of the
dtbpy ligand. The methyl protons of the equatorial and axial
alkyl groups appeared as two singlets in a 1:2 ratio at δ 0.88
and 0.98, indicative of the mer arrangement of the three alkyl
groups. The two doublets at δ -0.55 and 1.24 were assigned
to the methylene protons of the axial alkyl groups, whereas a
singlet at δ 2.60 was observed for those of the equatorial one.
The positive-ion FAB spectrum of 2 showed a molecular ion
peak at m/z 574 corresponding to [Mþ - CH2SiMe3 þ 1].
Ruthenium Dialkyl Complexes. Protonation of 2 with HCl
in hexane led to formation of a red precipitate characterized
as the dialkyl compound cis,cis-Ru(dtbpy)(CH2SiMe3)2-
(NO)Cl (3). Di- or trichloride compounds were not formed
even when excess HCl was used for the protonation. Unlike
2, 3 is air stable in both the solid state and solution. In the 1H
NMR spectrum, the SiMe3 protons appeared as two singlets
at δ -0.11 and 0.76 and the methylene protons appeared as
four doublets at δ 0.62, 1.89, 2.06, and 2.84, indicating that
the two alkyl groups are cis to each other. Similarly, proton-
ation of 2 with p-toluenesulfonic acid (HOTs) afforded
the dialkyl compound cis,cis-Ru(dtbpy)(CH2SiMe3)2(NO)-
Figure 1. Molecular structure of mer-Ru(dtbpy)(NO)(CH2Si-
Me3)3 (2). Hydrogen atoms are omitted for clarity. The ellipsoids
˚
are drawn at the 40% probability level. Selected bond lengths (A)
and angles (deg): Ru(1)-N(1) 1.693(2), Ru(1)-N(10) 2.139(2),
Ru(1)-N(21) 2.128(2), Ru(1)-C(31) 2.188(3), Ru(1)-C(32)
2.132(3), Ru(1)-C(33) 2.202(3); Ru(1)-N(1)-O(1) 175.5(2).
Substitution of 5 with Amines. The triflate ligand in 5 is labile
and can be readily replaced by heteroatom ligands. Substitution
reactions of 5 are summarized in Scheme 1. Treatment of 5 with
amines NH2R afforded the cationic amine complexes cis,
cis-[Ru(dtbpy)(CH2SiMe3)2(NO)(NH2R)][OTf] (R = mesityl
1
(6), 4-tol (7)). H NMR spectroscopy indicates that the two
alkyl groups in each of 6and 7are inequivalent and mutually cis,
consistent with the solid-state structure (vide infra). Attempts to
prepare Ru amido complexes by treatment of 6 and 7 with bases
such as n-BuLi and NaN(SiMe3)2 were unsuccessful.
Substitution of 5 with Anionic Ligands. Treatment of 5 with
sodium phenoxide afforded the phenoxide compound cis,
trans-Ru(dtbpy)(CH2SiMe3)2(NO)(OPh) (8). The 1H NMR
spectrum of 8 showed two singlets at δ 0.95 and 0.61
assignable to the t-Bu and SiMe3 groups, respectively, in-
dicating that the two cisoid alkyl groups are opposite to the
dtbpy ligand. The phenoxide in 8 is situated opposite the
nitrosyl apparently due to the “push-pull” effect19 between
the π-donating phenoxide and π-accepting nitrosyl ligands.
The existence of Ru-O π interaction is also evidenced by the
observed short Ru-O distance and large Ru-O-C angle
(vide infra).
Attempts to replace the triflate in 5 with other alkoxides
such as methoxide and tert-butoxide were unsuccessful.
However, treatment of 5 with NaOSiR3 led to isolation of
the siloxide complexes cis,trans-Ru(dtbpy)(CH2SiMe3)2-
(NO)(OSiR3) (R=Me (9), Ph (10)). Similar to 8, 1H NMR
spectroscopy indicates that in 9 and 10 the two alkyl groups
are opposite dtbpy and the nitrosyl is trans to the π-donating
siloxide group.
1
(OTs) (4), which exhibited a similar H NMR spectrum to
that of 3 (except for resonances of the tosylate ligand).
Attempts to prepare mixed alkyl compounds, Ru(dtbpy)-
(CH2SiMe3)2(NO)(R), by alkylation of 3 or 4 with alkylating
agents such as PhMgBr and PhLi were unsuccessful. Treat-
ment of 3 with silver triflate (AgOTf) in CH2Cl2 afforded
the triflate compound cis,cis-Ru(dtbpy)(CH2SiMe3)2(NO)-
(OTf) (5), which could also be prepared by direct proton-
ation of 2 with triflic acid. It may be noted that the reactions
of 2 with HX (X=Cl, OTs, OTf) resulted in selective cleavage
of the axial rather than equatorial Ru-C bond. The selective
reactivity of 2 with HX can be explained in terms of the
relative Ru-C bond strength and/or carbanion character of
the alkyl groups. The Ru-C(trans to C) bonds in 2 are longer
(as indicated in the solid-state structure, vide infra) and
weaker than the Ru-C(trans to N) bond due to the trans
influence of the alkyl group, and thus the cleavage of the
former is thermodynamically preferred.
Treatment of 5 with NaSR afforded the thiolate compounds
cis,cis-Ru(dtbpy)(CH2SiMe3)2(NO)(SR) (R = 2,6-Me2C6H3
(18) Leung, W. H.; Chim, J. L. C.; Wong, W. T. J. Chem. Soc., Dalton
Trans. 1997, 3227.
(19) (a) Poulton, J. T.; Sigalas, M. P.; Felting, K.; Streib, W. E.;
Eisenstein, O.; Caulton, K. G. Inorg. Chem. 1994, 33, 1476. (b) Poulton,
J. T.; Folting, K.; Streib, W. E.; Caulton, K. G. Inorg. Chem. 1992, 31, 3190.

5798 Organometallics, Vol. 28, No. 19, 2009
Chan et al.
Figure 2. Molecular structure of cis,cis-Ru(dtbpy)(CH2SiMe3)2-
(NO)Cl (3). Hydrogen atoms are omitted for clarity. The ellipsoids
˚
are drawn at the 40% probability level. Selected bond lengths (A)
and angles (deg): Ru(1A)-N(1A) 1.707(3), Ru(1A)-N(10A)
2.133(3), Ru(1A)-N(21A) 2.144(3), Ru(1A)-C(1A) 2.114(3),
Ru(1A)-C(5A) 2.138(4), Ru(1A)-Cl(1A) 2.4759(10), O(1A)-
N(1A)-Ru(1A) 171.2(3).
Figure 4. Molecular structure of cis,cis-Ru(dtbpy)(CH2SiMe3)2-
(NO)(OTf) (5). Hydrogen atoms are omitted for clarity. The
ellipsoids are drawn at the 25% probability level. Selected bond
lengths (A) and angles (deg): Ru(1)-N(1) 1.728(3), Ru(1)-N(10)
2.145(3), Ru(1)-N(21) 2.160(3), Ru(1)-C(2) 2.107(4), Ru(1)-
C(6) 2.100(4), Ru(1)-O(2) 2.266(3); O(1)-N(1)-Ru(1) 172.8(4).
˚
Figure 5. Molecular structure of the cation cis,cis-[Ru(dtbpy)-
(CH2SiMe3)2(NO)(4-tolNH2)]þ in 7. Hydrogen atoms are
omitted for clarity. The ellipsoids are drawn at the 40% prob-
˚
ability level. Selected bond lengths (A) and angles (deg): Ru-
Figure 3. Molecular structure of cis,cis-Ru(dtbpy)(NO)(CH2Si-
Me3)2(NO)(OTs) (4). Hydrogen atoms are omitted for clarity. The
ellipsoids are drawn at the 40% probability level. Selected bond
lengths (A) and angles (deg): Ru(1)-N(1) 1.712(2), Ru(1)-N(10)
2.154(2), Ru(1)-N(20) 2.138(2), Ru(1)-C(1) 2.127(3), Ru(1)-
C(5) 2.104(3), Ru(1)-O(2) 2.2045(18), O(1)-N(1)-Ru(1) 172.1(2).
(1)-N(1) 1.705(3), Ru(1)-N(2) 2.131(2), Ru(1)-N(3) 2.151(2),
Ru(1)-C(1) 2.141(3), Ru(1)-C(5) 2.127(3), Ru(1)-N(31)
2.263(3); O(1)-N(1)-Ru(1) 172.1(2), C(31)-N(31)-Ru(1)
117.35(19).
˚
[OsO3N]- and nitrosyl suggests the Ru-N(Os) π interaction
in 13 is not significant, consistent with the solid-state struc-
ture (vide infra).
(11) and SiPh3 (12)). 1H NMR spectroscopy indicates that in 11
and 12 the alkyl groups are inequivalent and the nitrosyl is
cis to the thiolate ligand. This suggests that for the Ru(II)
system thiolate is a weaker donor ligand than the oxygen
analogue, and therefore the trans arrangement between nitrosyl
and thiolate is not favored.
Treatment of 5 with K[OsO3N] afforded the nitrido-
bridged Ru(II)/Os(VIII) bimetallic complex cis,cis-Ru(dt-
bpy)(CH2SiMe3)2(NO)(NOsO3) (13). 13 exhibited a similar
1H NMR spectrum to 5, indicating that the nitridoosmate
ligand is cis to the nitrosyl. The cis arrangement between
Infrared Spectroscopy. The IR spectrum of 2 displayed the
N-O band at 1741 cm-1, which is considerably lower than
that of 1 (1871 cm-1), reflecting the electron-donating ability
of the alkyl ligand. To our knowledge, this is among the
lowest N-O stretching frequencies found for Ru(II) linear
nitrosyl complexes. The N-O stretching frequencies for the
dialkyl compounds cis,cis-Ru(dtbpy)(CH2SiMe3)2(NO)X
(X=Cl, OTs, OTf, amine, thiolate) are lower than that of
1 and lie in the range 1760-1809 cm-1. On the basis of the

Article
Organometallics, Vol. 28, No. 19, 2009 5799
Figure 6. Molecular structure of cis,trans-Ru(dtbpy)(CH2Si-
Me3)2(NO)(OPh) (8). Hydrogen atoms are omitted for clarity.
The ellipsoids are drawn at the 40% probability level. Selected
˚
bond lengths (A) and angles (deg): Ru(1)-N(1) 1.7095(13), Ru-
Figure 8. Molecular structure of cis,trans-Ru(dtbpy)(CH2SiMe3)2-
(NO)(OSiPh3) (10). Hydrogen atoms are omitted for clarity. The
ellipsoids are drawn at the 40% probability level. Selected bond
(1)-N(10) 2.2161(12), Ru(1)-N(21) 2.2019(12), Ru(1)-C(31)
2.1151(14), Ru(1)-C(35) 2.1160(14), Ru(1)-O(2) 2.0212(9);
O(1)-N(1)-Ru(1) 172.65(14), C(1)-O(2)-Ru(1) 128.72(9).
˚
lengths (A) and angles (deg): Ru(1)-N(1) 1.715(3), Ru(1)-N(30)
2.224(3), Ru(1)-N(40) 2.200(3), Ru(1)-C(19) 2.116(4), Ru(1)-
C(23) 2.113(4), Ru(1)-O(2) 1.994(2); O(1)-N(1)-Ru(1) 177.6(3),
Si(1)-O(2)-Ru(1) 150.51(15).
Figure 7. Molecular structure of cis,trans-Ru(dtbpy)(CH2Si-
Me3)2(NO)(OSiMe3) (9). Hydrogen atoms are omitted for clarity.
The ellipsoids are drawn at the 40% probability level. Selected
˚
bond lengths (A) and angles (deg): Ru(1A)-N(1A) 1.690(6),
Ru(1A)-N(20A) 2.221(4), Ru(1A)-N(30A) 2.230(4), Ru(1A)-
C(4A) 2.127(5), Ru(1A)-C(8A) 2.121(5), Ru(1A)-O(2A) 1.974(4);
O(1A)-N(1A)-Ru(1A) 175.3(4), Si(1A)-O(2A)-Ru(1A) 149.1(2).
Figure 9. Molecular structure of cis,cis-Ru(dtbpy)(CH2SiMe3)2-
(NO)(SSiPh3) (12). Hydrogen atoms are omitted for clarity. The
ellipsoids are drawn at the 40% probability level. Selected bond
IR data, the donor strength of X is ranked in the order 2,6-
Me2C6H3S->Ph3SiS->Cl>p-tolNH2>OTs>[OsO3N]->
OTf-. The measured νNO for 13 is similar to that for the
triflate compound 5, indicating the absence of Ru-N(Os) π
interaction in 13 and that [NOsO3]- behaves like a weakly
coordinating ligand. The Os-N (1030 cm-1) and Os-O
(910 and 886 cm-1) stretching frequencies are higher than
˚
lengths (A) and angles (deg): Ru(1)-N(1) 1.7114(17), Ru(1)-N(2)
2.1387(16), Ru(1)-N(3) 2.1451(16), Ru(1)-C(51) 2.117(2), Ru-
(1)-C(55) 2.156(2), Ru(1)-S(1) 2.4941(6); O(1)-N(1)-Ru(1)
172.20(16), Si(1)-S(1)-Ru(1) 115.37(3).
basis of the measured νNO, the donor strength of X in cis,
trans-Ru(dtbpy)(CH2SiMe3)2(NO)X is ranked in the order
Me3SiO->PhO->Ph3SiO-. It may noted that for related
trans-Ru(CO)X(H)(Pt-Bu2Me)2 complexes a slightly differ-
ent trend of ligand donor strength (Me3SiO- >Ph3SiO->
PhO-) was found.19
Crystal Structures. Complexes 2-5, 7-10, 12, and 13 have
been characterized by X-ray diffraction, and their structures
are shown in Figures 1-10, respectively. In 2, the geometry
around Ru is pseudo-octahedral with the nitrosyl opposite to
those for the free [OsO3N]- (1023 and 890, and 858 cm-1
,
respectively), suggesting that the Os-N and Os-O bonds in
[OsO3N]- are strengthened upon coordination to Ru(II).
A similar result has been found for related heterometallic
nitridoosmate complexes.18 The N-O stretching frequencies
for cis,trans-Ru(dtbpy)(CH2SiMe3)2(NO)X (X=phenoxide,
siloxide) complexes (1768-1774 cm-1) are similar to those of
the thiolate complexes despite Ru-O π interactions. On the

5800 Organometallics, Vol. 28, No. 19, 2009
Chan et al.
Figure 10. Structures of a pair of optical isomers of cis,cis-Ru(dtbpy)(CH2SiMe3)2(NO)(NOsO3) (13). Hydrogen atoms are omitted
˚
for clarity. The ellipsoids are drawn at the 40% probability level. Selected bond lengths (A) and angles (deg): Ru(1A)-N(1A) 1.689(13),
Ru(1B)-N(1B) 1.747(14), Ru(1A)-C(1A) 2.101(14), Ru(1A)-C(5A) 2.106(19), Ru(1B)-C(1B) 2.157(18), Ru(1B)-C(5B) 2.134(15),
Os(1A)-N(2A) 1.654(11), Os(1B)-N(2B) 1.742(13), Os-O 1.687(13)-1.760(11); O(4A)-N(1A)-Ru(1A) 167.9(13), O(4B)-
N(1B)-Ru(1B) 175.3(14), Os(1A)-N(2A)-Ru(1A) 163.7(7); Os(1B)-N(2B)-Ru(1B) 162.6(8).
˚
a pyridyl group, and the three alkyls adopt a mer arrange-
ment. The fac-trialkyl complex is not formed possibly be-
cause the trans arrangement between strong π-accepting
nitrosyl and trans-directing alkyl ligand is not favored,
although trans Ru nitrosyl alkyl compounds, e.g., trans-
Ru(OEP)(NO)(C6H4F-p) (OEP2-=octaethylporphyrin dia-
nion), in which the Ru-N-O linkage is bent and tilted,14d,20
are known. It may also be noted that related nitrosyl
trihydride complexes MH3(NO)L2 (M=Ru, Os; L=PR3)
also exhibit a mer geometry. However, in MH3(NO)(PR3)2
the nitrosyl is trans to a hydride instead of L.21 Such a
geometry is not possible for 2 because of the bidentate
binding mode of dtbpy. As expected, the Ru-C distances
The Ru-S distance of 2.4941(6) A in 12 is longer than that in
[Ru(NO)(SAr)4]- (Ar=mesityl) (2.385 A).22 The relatively
˚
small Ru-S-C angle (115.37(3)o) suggests that Ru-S π
interactions, if any, are not signficant.
Complexes 8-10 exhibit a cis,trans geometry with the
nitrosyl opposite the phenoxide/siloxide ligand and the two
cisoid alkyl groups opposite dtbpy. The Ru-C distances in
˚
the range 2.113(4)-2.127(5) A are similar to those of the cis,
˚
cis-complexes. The Ru-O distance in 8 (2.0212(9) A) is
shorter than that in TpRu(PMe3)2(OPh) (Tp- = hydrido-
˚
trispyrazolylborate) (2.102(2) A), while the Ru-O-C angle
in the former (128.72(9)o) is smaller than that of the latter
(133.2(2)o).23 The Ru-O distance in 9 (1.974(4) A) is similar
˚
˚
for the axial alkyls (2.188(2) and 2.202(3) A) are longer than
to those in cis-[RuIII(L)(OSiMe3)2]þ (L = 3,6-hexamethyl-
3,6-diazaoctane-1,8-diamine) (1.977 A),24 but the Ru-O-Si
0
˚
˚
the equatorial one (2.132(3) A). The C(axial)-Ru-C (axial)
unit is slightly bent, with an angle of 165.49(10)o presumably
due to mutual trans influence of the alkyl ligands. Also, the
Ru-C(axial) bonds are slightly bent away from the Ru-NO
bond with the C(axial)-Ru-NO angles of 98.33(12)° and
angle (149.1(2)o) is smaller than those of the latter (av
˚
172.5°). The Ru-O distance in 10 (1.994(2) A) is slightly
shorter than that in Ru(OSiPh3)(CO)(H)(Pt-Bu2Me)2 (av
2.057(4) A), in which the siloxide is trans to carbonyl,19 but
˚
o
˚
95.12(12) . The Ru-NO distance of 1.693(2) A and the
the Ru-O-Si angle (150.51(15)o) is smaller that that in the
latter (av 165.5°). The observed large Ru-O-C/Si bond
angles in 8-10 are indicative of Ru-O π interactions. The
Ru-N-O angle of 175.5(2)o are typical for Ru(II) linear
nitrosyl complexes.
˚
Complexes 3-5, 7, and 12 exhibit cis,cis geometry with the
alkyls cis to each other and the nitrosyl opposite a pyridyl
group. The Ru-C distances in these complexes are in the
Ru-NO distances (1.690(6)-1.715(3) A) and Ru-N-O
angles (172.65(14)-177.6(3)o) in 8-10 are similar to those
in 2 and rather insensitive to the trans ligand X.
˚
range 2.100(4)-2.156(2) A, which are similar to the Ru-
Complex 13 exhibits a cis,cis geometry with the [OsO3N]-
ligand trans to an alkyl. Unlike the crystal structures of the
above cis,cis-Ru(dtbpy)R2(NO)X complexes, the asym-
metric unit of 13 consists of a pair of molecules that are
optical isomers of each other. The Ru-N-Os unit is roughly
C(equatorial) distance in 2. The Ru-Cl distance (2.4759(10)
A) in 3 is rather long due to the trans influence of the alkyl.
˚
(20) Richter-Addo, G. B.; Wheeler, R. A; Hixson, C. A.; Chen, L.;
Khan, M. A.; Ellison, M. K.; Schulz, C. E.; Scheidt, W. R. J. Am. Chem.
Soc. 2001, 123, 6314.
(21) Yandulov, D. V.; Huang, D. J.; Huffman, J. C.; Caulton, K. G.
Inorg. Chem. 2000, 39, 1919.
(22) Soong, S.-L.; Hain, J. H., Jr.; Millar, M.; Koch, S. A. Organo-
metallics 1988, 7, 556.
(23) Feng, Y.; Lail, M.; Foley, N. A.; Gunnoe, T. B.; Barakat, K. A.;
Cundari, T. R.; Petersen, J. L. J. Am. Chem. Soc. 2006, 128, 7982.
(24) Chiu, W.-H.; Che, C.-M.; Mak, T. C. W. Polyhedron 1996, 15,
1129.

Article
Organometallics, Vol. 28, No. 19, 2009 5801
linear (av 163.2°). The rather long Ru-N(nitride) and short
easily cleaved by Brønsted acids to give cis-dialkyl complexes.
The triflate complex 5 proved to be a good starting material for
preparations of Ru(II) alkyl complexes containing heteroatom
ligands. Substitution of 5 with amines and thiolate affords
dialkyl complexes with the nitrosyl opposite a pyridyl group,
whereas that with phenoxide and siloxide resulted in trans
nitrosyl phenoxide/siloxide complexes. The study of organo-
metallic chemistry and catalytic activity of Ru di- and trialkyl
complexes with dtbpy is underway.
˚
Os-N distances (av 2.104 and 1.698 A, respectively) indicate
that Ru-N(Os) π interaction is not significant, and 13 is
best described as an unsymmetrically nitrido-bridged Ost
NfRu complex. By comparison, the Ru-N and Os-N
distances in trans-Ru(OEP)(NO)(NOsO3), which exhibits
substantial Ru-N(Os) π interactions, are 1.83(2) and
25
˚
1.79(1) A, respectively. The Os-N and Os-O distances
of the [OsO3N]- ligand in 13 (av 1.698 and 1.732 A,
˚
respectively) are similar to those in free [OsO3N]- (1.67(2)
26
˚
and 1.744(1) A).
Acknowledgment. This work has been supported by
the Hong Kong Research Grants Council (project num-
ber 601708). We thank Dr. Herman H. Y. Sung for
solving the crystal structures.
Conclusions
We have synthesized and structurally characterized the first
Ru(II) nitrosyl mer-trialkyl compound with a 2,20-bipyridyl
ligand. One of the mutually trans Ru-C bonds in 2 can be
Supporting Information Available: Tables of crystal data,
final atomic coordinates, anisotropic thermal parameters, and
complete bond lengths and angles for complexes 2, 3 0.25C7H8,
3
(25) Leung, W.-H.; Chim, J. L. C.; Lai, W.; Lam, L.; Wong, W.-T.;
Chan, W.-H.; Yeung, C.-H. Inorg. Chim. Acta 1999, 290, 28.
(26) Kafitz, W.; Weller, F.; Dehnicke, K. Z. Anorg. Allg. Chem. 1982,
590, 175.
4 0.5H2O, 5, 7 1.5H2O, 8, 9 0.25C4H8O, 10, 12 C6H14, and 13.
This material is available free of charge via the Internet at http://
pubs.acs.org.
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