Synthesis, structures, and properties of group 9- and group 10-group 6 heterodinuclear nitrosyl complexes

Article abstract of DOI:10.1021/ic702309h

The reaction of the group 9 bis(hydrosulfido) complexes [Cp*M(SH)₂(PMe₃)] (M = Rh, Ir; Cp* = η⁵-C₅Me₅) with the group 6 nitrosyl complexes [Cp*M′Cl₂(NO)] (M′ = Mo, W) in the presence of NEt₃ affords a series of bis(sulfido)-bridged early-late heterobimetallic (ELHB) complexes [Cp*M(PMe₃)(μ-S) ₂M′(NO)Cp*] (2a, M = Rh, M′ = Mo; 2b, M = Rh, M′ = W; 3a, M = Ir, M′ = Mo; 3b, M = Ir, M′ = W). Similar reactions of the group 10 bis(hydrosulfido) complexes [M(SH)₂(dppe)] (M = Pd, Pt; dppe = Ph₂P(CH₂)₂PPh₂), [Pt(SH)₂(dppp)] (dppp = Ph₂P(CH₂) ₃PPh₂), and [M(SH)₂(dpmb)] (dpmb = o-C ₆H₄(CH₂PPh₂)₂) give the group 10-group 6 ELHB complexes [(dppe)M(μ-S)₂M′(NO) Cp*] (M = Pd, Pt; M′ = Mo, W), [(dppp)Pt(μ-S)₂M′ (NO)Cp*] (6a, M′ = Mo; 6b, M′ = W), and [(dpmb)M(μ-S) ₂M′(NO)Cp*] (M = Pd, Pt; M′ = Mo, W), respectively. Cyclic voltammetric measurements reveal that these ELHB complexes undergo reversible one-electron oxidation at the group 6 metal center, which is consistent with isolation of the single-electron oxidation products [Cp*M(PMe₃)(μ-S)₂M′(NO)Cp*][PF ₆] (M = Rh, Ir; M′ = Mo, W). Upon treatment of 2b and 3b with ROTf (R = Me, Et; OTf = OSO₂CF₃), the O atom of the terminal nitrosyl ligand is readily alkylated to form the alkoxyimido complexes such as [Cp*Rh(PMe₃)(μ-S)₂W(NOMe)Cp*][OTf]. In contrast, methylation of the Rh-, Ir-, and Pt-Mo complexes 2a, 3a, and 6a results in S-methylation, giving the methanethiolato complexes [Cp*M(PMe₃)(μ-SMe)(μ-S)Mo(NO)Cp*][BPh₄] (M = Rh, Ir) and [(dppp)Pt(μ-SMe)(μ-S)Mo(NO)Cp*][OTf], respectively. The Pt-W complex 6b undergoes either S- or O-methylation to form a mixture of [(dppp)Pt(μ-SMe)(μ-S)W(NO)Cp*][OTf] and [(dppp)Pt(μ-S) ₂W(NOMe)Cp*][OTf]. These observations indicate that O-alkylation and one-electron oxidation of the dinuclear nitrosyl complexes are facilitated by a common effect, i.e., donation of electrons from the group 9 or 10 metal center, where the group 9 metals behave as the more effective electron donor.

Full text of DOI:10.1021/ic702309h

Inorg. Chem. 2008, 47, 4264-4274
Synthesis, Structures, and Properties of Group 9- and Group
10-Group 6 Heterodinuclear Nitrosyl Complexes
Kazuya Arashiba,† Hidetaka Iizuka,† Shoji Matsukawa,‡ Shigeki Kuwata,§ Yoshiaki Tanabe,†
Masakazu Iwasaki,¶ and Youichi Ishii*,†
Department of Applied Chemistry, Faculty of Science and Engineering, Chuo UniVersity, Kasuga,
Bunkyo-ku, Tokyo 112-8551, Japan, Institute of Industrial Science, The UniVersity of Tokyo,
Komaba, Meguro-ku, Tokyo 153-8505, Japan, Department of Applied Chemistry, Graduate School
of Science and Engineering, Tokyo Institute of Technology, O-okayama, Meguro-ku,
Tokyo 152-8552, Japan, and Department of Applied Chemistry, Faculty of Engineering, Saitama
Institute of Technology, Okabe, Saitama 369-0293, Japan
Received November 24, 2007
5
The reaction of the group 9 bis(hydrosulfido) complexes [Cp*M(SH)2(PMe3)] (M ) Rh, Ir; Cp* ) η -C5Me5) with
the group 6 nitrosyl complexes [Cp*M′Cl2(NO)] (M′ ) Mo, W) in the presence of NEt3 affords a series of bis(sulfido)-
bridged early-late heterobimetallic (ELHB) complexes [Cp*M(PMe3)(µ-S)2M′(NO)Cp*] (2a, M ) Rh, M′ ) Mo; 2b,
M ) Rh, M′ ) W; 3a, M ) Ir, M′ ) Mo; 3b, M ) Ir, M′ ) W). Similar reactions of the group 10 bis(hydrosulfido)
complexes [M(SH)2(dppe)] (M ) Pd, Pt; dppe ) Ph2P(CH2)2PPh2), [Pt(SH)2(dppp)] (dppp ) Ph2P(CH2)3PPh2),
and [M(SH)2(dpmb)] (dpmb ) o-C6H4(CH2PPh2)2) give the group 10-group 6 ELHB complexes [(dppe)M(µ-
S)2M′(NO)Cp*] (M ) Pd, Pt; M′ ) Mo, W), [(dppp)Pt(µ-S)2M′(NO)Cp*] (6a, M′ ) Mo; 6b, M′ ) W), and [(dpmb)M(µ-
S)2M′(NO)Cp*] (M ) Pd, Pt; M′ ) Mo, W), respectively. Cyclic voltammetric measurements reveal that these
ELHB complexes undergo reversible one-electron oxidation at the group 6 metal center, which is consistent with
isolation of the single-electron oxidation products [Cp*M(PMe3)(µ-S)2M′(NO)Cp*][PF6] (M ) Rh, Ir; M′ ) Mo, W).
Upon treatment of 2b and 3b with ROTf (R ) Me, Et; OTf ) OSO2CF3), the O atom of the terminal nitrosyl ligand
is readily alkylated to form the alkoxyimido complexes such as [Cp*Rh(PMe3)(µ-S)2W(NOMe)Cp*][OTf]. In contrast,
methylation of the Rh-, Ir-, and Pt-Mo complexes 2a, 3a, and 6a results in S-methylation, giving the
methanethiolato complexes [Cp*M(PMe3)(µ-SMe)(µ-S)Mo(NO)Cp*][BPh4] (M ) Rh, Ir) and [(dppp)Pt(µ-SMe)(µ-
S)Mo(NO)Cp*][OTf], respectively. The Pt-W complex 6b undergoes either S- or O-methylation to form a mixture
of [(dppp)Pt(µ-SMe)(µ-S)W(NO)Cp*][OTf] and [(dppp)Pt(µ-S)2W(NOMe)Cp*][OTf]. These observations indicate that
O-alkylation and one-electron oxidation of the dinuclear nitrosyl complexes are facilitated by a common effect, i.e.,
donation of electrons from the group 9 or 10 metal center, where the group 9 metals behave as the more effective
electron donor.
Introduction
centers may lead to unique activation and effective trans-
formation of substrate molecules.1 Yet, it is little understood
how early and late metals can interact in actual ELHB
complexes, and obviously more information about such
cooperative effects is needed to better design effective ELHB
systems.2 In the course of our study on multinuclear
complexes, we have revealed that hydrosulfido complexes
serve as versatile metalloligands to construct various ELHB
Early-late heterobimetallic (ELHB) complexes in which
an electron-deficient early-transition metal and an electron-
rich late-transition metal are located in close proximity have
recently been attracting considerable attention because the
cooperative effects between such significantly different metal
* To whom correspondence should be addressed. E-mail: ishii@
chem.chuo-u.ac.jp.
†
Chuo University.
The University of Tokyo.
Tokyo Institute of Technology.
Saitama Institute of Technology.
‡
§
(1) (a) Wheatley, N.; Kalck, P. Chem. ReV. 1999, 99, 3379–3419. (b)
Stephan, D. W. Coord. Chem. ReV. 1989, 95, 41–107.
¶
4264 Inorganic Chemistry, Vol. 47, No. 10, 2008
10.1021/ic702309h CCC: $40.75  2008 American Chemical Society
Published on Web 04/22/2008

Heterodinuclear Nitrosyl Complexes
complexes.3 In this study, we have designed group 9- and
group 10-group 6 sulfido-bridged nitrosyl complexes [Cp*M-
(PMe3)(µ-S)2M′(NO)Cp*] (M ) Rh, Ir; M′ ) Mo, W; Cp*
) η5-C5Me5) and [L2M(µ-S)2M′(NO)Cp*] [M ) Pd, Pt; M′
) Mo, W; L2 ) 1,2-bis(diphenylphosphino)ethane (dppe),
1,2-bis(diphenylphosphino)propane (dppp), o-bis(diphe-
nylphosphinomethyl)benzene (dpmb)] and investigated the
factors that control the activation of NO at the group 6 metal
center.
It is well-known that the nitrosyl ligand exhibits charac-
teristic redox behavior and reactivities depending upon the
electronic states of the metal centers.4 In particular, the
terminally bound linear nitrosyl is an effective π acid and
therefore is expected to be activated toward electrophilic
attack, but such reactivity has poorly been exploited with
actual transition-metal nitrosyl complexes.5 On the basis of
our previous results on multinuclear nitrosyl complexes,6 we
have embarked on investigating the origin of the ELHB
cooperative effect in nitrosyl activation at dinuclear com-
plexes. In this paper, we report that in the above-mentioned
group 9- and group 10-group 6 dinuclear complexes the
electron donation from the electron-rich late-transition (group
9 or 10) metal center plays a critical role in the activation of
the nitrosyl ligand at the group 6 metal center toward
electrophilic O-alkylation. Part of the results have already
been published in a Communication.7
dried and distilled over P4O10, while NEt3 was dried and distilled
over KOH. The other solvents (dehydrated-grade) were purchased
from Aldrich and used as received. [Cp*M(SH)2(PMe3)] (M ) Rh,
Ir),8 [Cp*M′Cl2(NO)] (1a, M′ ) Mo; 1b, M′ ) W),9 [M(SH)2-
(dppe)] (M ) Pd, Pt),10 [Pt(SH)2(dppp)],11 and [MCl2(dpmb)] (M
) Pd, Pt)12 were prepared according to the literature methods. 1H
(500 or 400 MHz) and 31P{1H} (202 or 121 MHz) NMR spectra
were recorded on a JEOL ECA-500, JEOL JNM-GSX-400, or
Varian Mercury-300 spectrometer by using CDCl3 as the solvent.
IR spectra were recorded on a Jasco FT/IR-410 spectrometer using
KBr pellets. Elemental analyses were performed on a Perkin-Elmer
2400II CHN analyzer. Cyclic voltammetry studies were performed
with a BAS CV-50W analyzer. Potentials were measured at a
glassy-carbon working electrode in a CH2Cl2 solution containing
0.1 M (nBu4N)(BF4) and a 2 mM sample at 25 °C.
Preparation of [Cp*M(PMe3)(µ-S)2M′(NO)Cp*] (2a, M )
Rh, M′ ) Mo; 2b, M ) Rh, M′ ) W; 3a, M ) Ir, M′ ) Mo;
3b, M ) Ir, M′ ) W). The following procedure for the preparation
of [Cp*Rh(PMe3)(µ-S)2W(NO)Cp*] (2b) is representative. To a
solution of 1b (475 mg, 1.13 mmol) in THF (40 mL) at -40 °C
were added [Cp*Rh(SH)2(PMe3)] (430 mg, 1.13 mmol) and NEt3
(0.33 mL, 2.37 mmol), and the mixture was warmed gradually to
room temperature. After 3 h of stirring at room temperature, the
dark-brown solution was dried up in vacuo, and the residue was
dissolved in CH2Cl2 (15 mL) to load onto an alumina column, where
the adsorbed mixture was eluted with THF-hexane (2:1). The main
green band was collected, and the solvent was removed in vacuo.
Recrystallization of the residual dark-green solid from benzene (20
mL)-hexane (45 mL) afforded 2b as dark-green crystals (472 mg,
0.649 mmol, 57% yield). 31P{1H} NMR: δ 7.6 (d, 1JRhP ) 147 Hz,
Experimental Section
4
PMe3). 1H NMR: δ 1.99 (s, 15H, Cp*W), 1.92 (d, JPH ) 2.4 Hz,
15H, Cp*Rh), 1.25 (d, 2JPH ) 11.0 Hz, 9H, PMe3). IR (cm-1): 1490
(νNO). Anal. Calcd for C23H39NOPRhS2W: C, 37.98; H, 5.40; N,
1.93. Found: C, 38.10; H, 5.45; N, 2.00.
General Remarks. All manipulations were carried out under
an atmosphere of nitrogen by using standard Schlenk techniques.
Dichloromethane (CH2Cl2) and 1,2-dichloroethane (C2H4Cl2) were
2a: dark-green crystals, 79% yield. 31P{1H} NMR: δ 11.2 (d,
1
1JRhP ) 147 Hz, PMe3). H NMR: δ 1.91 (s, 15H, Cp*Mo), 1.89
(2) (a) Kajitani, H.; Seino, H.; Mizobe, Y. Organometallics 2007, 26,
3499–3508. (b) Hernandez-Gruel, M. A. F.; Lahoz, F. J.; Dobrinovich,
I. T.; Modrego, F. J.; Oro, L. A.; Pérez-Torrente, J. J. Organometallics
2007, 26, 2616–2622. (c) Takei, I.; Kobayashi, K.; Dohki, K.; Nagao,
S.; Mizobe, Y.; Hidai, M. Chem. Lett. 2007, 36, 546–547. (d) Komuro,
T.; Kawaguchi, H.; Lang, J.; Nagasawa, T.; Tatsumi, K. J. Organomet.
Chem. 2007, 692, 1–9. (e) Herbst, K.; Söderhjelm, E.; Nordlander,
E.; Dahlenburg, L.; Brorson, M. Inorg. Chim. Acta 2007, 360, 2697–
2703. (f) Molina, R. H.; Kalinina, I.; Sokolov, M.; Clausen, M.; Platas,
J. G.; Vicent, C.; Llusar, R. Dalton Trans. 2007, 550–557. (g)
Kuwabara, J.; Takeuchi, D.; Osakada, K. Chem. Commun. 2006, 3815–
3817. (h) Herberhold, M.; Jin, G.-X.; Rheingold, A. L. Z. Anorg. Allg.
Chem. 2005, 631, 135–140. (i) Cornelissen, C.; Erker, G.; Kehr, G.;
Fröhlich, R. Organometallics 2005, 24, 214–225. (j) Hidai, M.;
Kuwata, S.; Mizobe, Y. Acc. Chem. Res. 2000, 33, 46–52. (k) Hanna,
T. A.; Baranger, A. M.; Bergman, R. G. J. Am. Chem. Soc. 1995,
117, 11363–11364.
4
2
(d, JPH ) 2.7 Hz, 15H, Cp*Rh), 1.26 (d, JPH ) 11.0 Hz, 9H,
PMe3). IR (cm-1): 1515 (νNO). Anal. Calcd for C23H39MoNOPRhS2:
C, 43.20; H, 6.15; N, 2.19. Found: C, 43.52; H, 6.19; N, 2.27.
3a: dark-green crystals, 66% yield. 31P{1H} NMR: δ -22.8 (s,
PMe3). 1H NMR: δ 1.97 (s, 15H, Cp*Mo), 1.89 (d, 4JPH ) 1.5 Hz,
15H, Cp*Ir), 1.34 (d, 2JPH ) 11.0 Hz, 9H, PMe3). IR (cm-1): 1521
(νNO). Anal. Calcd for C23H39IrMoNOPS2: C, 37.90; H, 5.39; N,
1.92. Found: C, 38.08; H, 5.44; N, 1.97.
3b: dark-violet crystals, 48% yield. 31P{1H} NMR: δ -28.6 (s,
4
PMe3). 1H NMR: δ 2.02 (s, 15H, Cp*W), 1.93 (d, JPH ) 1.7 Hz,
15H, Cp*Ir), 1.34 (d, 2JPH ) 11.0 Hz, 9H, PMe3). IR (cm-1): 1491
(νNO). Anal. Calcd for C23H39IrNOPS2W: C, 33.82; H, 4.81; N,
1.71. Found: C, 33.68; H, 4.86; N, 1.79.
(3) (a) Kuwata, S.; Nagano, T.; Matsubayashi, A.; Ishii, Y.; Hidai, M.
Inorg. Chem. 2002, 41, 4324–4330. For reviews of these types of
synthetic methods for S-bridged complexes, see: (b) Kuwata, S.; Hidai,
M. Coord. Chem. ReV. 2001, 213, 211–305. (c) Peruzzini, M.; de los
Rios, I.; Romerosa, A. Prog. Inorg. Chem. 2001, 49, 169–453.
(4) (a) Hayton, T. W.; Legzdins, P.; Sharp, W. B. Chem. ReV. 2002, 102,
935–991. (b) Ford, P. C.; Lorkovic, I. M. Chem. ReV. 2002, 102, 993–
1017. (c) Kuwata, S.; Kura, S.; Ikariya, T. Polyhedron 2007, 26, 4659–
4663. (d) Landry, V. K.; Parkin, G. Polyhedron 2007, 26, 4751–4757.
(e) Lis, E. C., Jr.; Delafuente, D. A.; Lin, Y.; Mocella, C. J.; Todd,
M. A.; Liu, W.; Sabat, M.; Myers, W. H.; Harman, W. D. Organo-
metallics 2006, 25, 5051–5058.
Preparation of [M(SH)2(dpmb)] (M ) Pd, Pt). The following
procedure for the preparation of [Pt(SH)2(dpmb)] is representative.
A suspension of [PtCl2(dpmb)] (2.79 g, 3.77 mmol) and NaSH (549
(8) (a) Klein, D. P.; Kloster, G. M.; Bergman, R. G. J. Am. Chem. Soc.
1990, 112, 2022–2024. (b) Dobbs, D. A.; Bergman, R. G. Inorg. Chem.
1994, 33, 5329–5336.
(9) Dryden, N. H.; Legzdins, P.; Batchelor, R. J.; Einstein, F. W. B.
Organometallics 1991, 10, 2077–2081.
(10) (a) Schmidt, M.; Hoffmann, G. G.; Höller, R. Inorg. Chim. Acta 1979,
32, L19–L20. (b) Kato, H.; Seino, H.; Mizobe, Y.; Hidai, M. Inorg.
Chim. Acta 2002, 339, 188–192.
(5) Sharp, W. B.; Legzdins, P.; Patrick, B. O. J. Am. Chem. Soc. 2001,
123, 8143–8144.
(6) (a) Hattori, T.; Matsukawa, S.; Kuwata, S.; Ishii, Y.; Hidai, M. Chem.
Commun. 2003, 510, 511. (b) Matsukawa, S.; Kuwata, S.; Hidai, M.
Inorg. Chem. 2000, 39, 791–798.
(11) Mas-Ballesté, R.; Aullón, G.; Champkin, P. A.; Clegg, W.; Mégret,
C.; González-Duarte, P.; Lledós, A. Chem.sEur. J. 2003, 9, 5023–
5035.
(7) Arashiba, K.; Matsukawa, S.; Kuwata, S.; Tanabe, Y.; Iwasaki, M.;
Ishii, Y. Organometallics 2006, 25, 560–562.
(12) Brown, M. D.; Levason, W.; Reid, G.; Watts, R. Polyhedron 2005,
24, 75–87.
Inorganic Chemistry, Vol. 47, No. 10, 2008 4265

Arashiba et al.
mg, 9.79 mmol) in EtOH (70 mL) and benzene (30 mL) was
refluxed for 17 h. The resulting suspension was cooled to room
temperature. The precipitate was collected by filtration, washed with
H2O, EtOH, and hexane, and dried in vacuo to afford
[Pt(SH)2(dpmb)] as a white solid (2.23 g, 3.03 mmol, 80% yield).
31P{1H} NMR: δ 1.1 (s with 195Pt satellites, 1JPtP ) 2928 Hz, dpmb).
1H NMR: δ 7.85-7.81, 7.48-7.41 (m, total 20H, Ph of dpmb),
7.00, 6.40 (br, 2H each, C6H4 of dpmb), 3.94 (d with 195Pt satellites,
15H, Cp*). IR (cm-1): 1535 (νNO). Anal. Calcd for C37H41-
MoNOP2PtS2: C, 47.64; H, 4.43; N, 1.50. Found: C, 47.88; H, 4.43;
N, 1.45.
6b: brown solids, 56% yield. 31P{1H} NMR: δ -8.5 (s with 195Pt
satellites, 1JPtP ) 3125 Hz, dppp). 1H NMR: δ 7.63-7.35 (m, 20H,
Ph of dppp), 2.66-2.51 (br, 4H, CH2 of dppp), 2.12-1.88 (br, 2H,
CH2 of dppp), 1.78 (s, 15H, Cp*). IR (cm-1): 1499 (νNO). Anal.
Calcd for C37H41NOP2PtS2W: C, 43.54; H, 4.05; N, 1.37. Found:
C, 43.65; H, 4.08; N, 1.30.
3
2JPH ) 10.0 Hz, JPtH ) 32.5 Hz, 4H, CH2 of dpmb), -0.31 (d
with 195Pt satellites, 3JPH ) 7.5 Hz, 2JPtH ) 49.5 Hz, 2H, SH). Anal.
Calcd for C32H30P2PdS2: C, 52.24; H, 4.11. Found: C, 51.93; H,
3.97.
Preparation of [(dpmb)M(µ-S)2M′(NO)Cp*] (7a, M ) Pd,
M′ ) Mo; 7b, M ) Pd, M′ ) W; 8a, M ) Pt, M′ ) Mo; 8b,
M ) Pt, M′ ) W). These complexes were obtained from
[M(SH)2(dpmb)] (M ) Pd, Pt) by a procedure similar to that
described for 4a. 7a ·Et2O·0.5CH2Cl2: eluted with CH2Cl2, brown
[Pd(SH)2(dpmb)]: yellow solid, 46% yield. 31P{1H} NMR: δ 11.9
1
(s, dpmb). H NMR: δ 7.80-7.43 (m, 20H, Ph of dpmb), 6.99,
6.39 (br, 2H each, C6H4 of dpmb), 3.80 (d, JPH ) 9.0 Hz, 4H,
crystals, 52% yield. 31P{1H} NMR: δ 7.8 (s, dpmb). H NMR: δ
2
1
CH2 of dpmb), -0.30 (d, 3JPH ) 7.0 Hz, 2H, SH). Anal. Calcd for
7.92-7.41 (m, 20H, Ph of dpmb), 6.72, 5.99 (m, 2H each, C6H4 of
dpmb), 4.35, 3.67 (m, 2H each, CH2 of dpmb), 1.39 (s, 15H, Cp*.
IR (cm-1): 1525 (νNO). Anal. Calcd for C46.5H54ClMoNO2P2PdS2:
C, 54.60; H, 5.32; N, 1.37. Found: C, 54.86; H, 5.31; N, 1.36.
7b·CH2Cl2: eluted with CH2Cl2-MeOH (100:2), dark-blue
C32H30P2PdS2: C, 59.40; H, 4.67. Found: C, 59.18; H, 4.72.
Preparation of [(dppe)M(µ-S)2M′(NO)Cp*] (4a, M ) Pd,
M′ ) Mo; 4b, M ) Pd, M′ ) W; 5a, M ) Pt, M′ ) Mo; 5b,
M ) Pt, M′ ) W). The following procedure for the preparation
of [(dppe)Pd(µ-S)2Mo(NO)Cp*] (4a) is representative. To a suspen-
sion of [Pd(SH)2(dppe)] (355 mg, 0.62 mmol) in THF (20 mL) at
-60 °C were added 1a (206.4 mg, 0.62 mmol) in THF (20 mL)
and NEt3 (0.17 mL, 1.24 mmol), and the mixture was warmed
gradually to room temperature with stirring. The dark-brown
suspension was stirred overnight and then dried in vacuo. The
resultant residue was dissolved in CH2Cl2 and loaded on an alumina
column. The main brown band eluted with CH2Cl2-MeOH (100:
2) was collected, and the volatile materials were removed in vacuo.
Recrystallization of the residual dark-brown solid from
CH2Cl2-hexane afforded 4a·CH2Cl2 as brown crystals (294 mg,
0.32 mmol, 52% yield). 31P{1H} NMR: δ 60.3 (s, dppe). 1H NMR:
δ 7.78-7.41 (m, 20H, Ph of dppe), 2.45 (br, 4H, CH2 of dppe),
1.79 (s, 15H, Cp*). IR (cm-1): 1535 (νNO). Anal. Calcd for
C37H41Cl2MoNOP2PdS2: C, 48.56; H, 4.52; N, 1.53. Found: C,
48.62; H, 4.54; N, 1.50.
1
crystals, 76% yield. 31P{1H} NMR: δ 3.3 (s, dpmb). H NMR: δ
7.94-7.40 (m, 20H, Ph of dpmb), 6.70, 5.97 (m, 2H each, C6H4 of
dpmb), 4.32, 3.66 (m, 2H each, CH2 of dpmb), 1.43 (s, 15H, Cp*).
IR (cm-1): 1482 (νNO). Anal. Calcd for C43H45Cl2NOP2PdS2W: C,
47.86; H, 4.20; N, 1.30. Found: C, 47.88; H, 4.20; N, 1.30. Crystals
of 7b·MeCN suitable for X-ray analysis were obtained by further
recrystallization from MeCN-Et2O.
8a·Et2O·0.5CH2Cl2: eluted with CH2Cl2-MeOH (100:2), green
crystals, 58% yield. 31P{1H} NMR: δ 0.3 (s with 195Pt satellites,
1
1JPtP ) 3266 Hz, dpmb). H NMR: δ 7.89-7.42 (m, 20H, Ph of
dpmb), 6.74, 6.04 (m, 2H each, C6H4 of dpmb), 4.31, 3.91 (m, 2H
each, CH2 of dpmb), 1.42 (s, 15H, Cp*). IR (cm-1): 1525 (νNO).
Anal. Calcd for C46.5H54ClMoNOP2PtS2: C, 50.25; H, 4.90; N, 1.26.
Found: C, 50.44; H, 4.97; N, 1.28.
8b ·Et2O·0.5CH2Cl2: eluted with CH2Cl2-MeOH (100:2), green
crystals, 60% yield. 31P{1H} NMR: δ -4.1 (s with 195Pt satellites,
1
1JPtP ) 3332 Hz, dpmb). H NMR: δ 7.90-7.43 (m, 20H, Ph of
4b·C2H4Cl2: recrystallized from C2H4Cl2-hexane, dark-purple
dpmb), 6.73, 6.02 (m, 2H each, C6H4 of dpmb), 4.37, 3.92 (m, 2H
each, CH2 of dpmb), 1.48 (s, 15H, Cp*). IR (cm-1): 1482 (νNO).
Anal. Calcd for C46.5H54ClNO2P2PtS2W: C, 46.57; H, 4.54; N, 1.17.
Found: C, 46.37; H, 4.45; N, 1.14.
1
crystals, 63% yield. 31P{1H} NMR: δ 55.3 (s, dppe). H NMR: δ
7.78-7.41 (m, 20H, Ph of dppe), 2.45 (br, 4H, CH2 of dppe), 1.79
(s, 15H, Cp*). IR (cm-1): 1499 (νNO). Anal. Calcd for
C38H43Cl2NOP2PdS2W: C, 44.88; H, 4.26; N, 1.38. Found: C, 44.68;
H, 4.28; N, 1.36.
Preparation of [Cp*M(PMe3)(µ-S)2M′(NO)Cp*][PF6] (9a,
M ) Rh, M′ ) Mo; 9b, M ) Rh, M′ ) W; 10a, M ) Ir, M′
) Mo; 10b, M ) Ir, M′ ) W). The following procedure for the
preparation of [Cp*Rh(PMe3)(µ-S)2W(NO)Cp*][PF6] (9b) is rep-
resentative. To a dark-green solution of 2b (43 mg, 0.059 mmol)
in CH2Cl2 (5 mL) was added [Cp2Fe][PF6] (20 mg, 0.060 mmol;
Cp ) η5-C5H5), and the mixture was stirred at room temperature
for 1 h. The resultant brown solution was filtered, and the slow
addition of hexane (12 mL) to the concentrated filtrate (ca. 3 mL)
afforded 9b as dark-brown crystals (50 mg, 0.057 mmol, 97%
yield). IR (cm-1): 1581 (νNO). Anal. Calcd for C23H39F6-
NOP2RhS2W: C, 31.67; H, 4.51; N, 1.61. Found: C, 31.47; H, 4.51;
N, 1.62.
5a·CH2Cl2: eluted with CH2Cl2-MeOH (100:1), light-green
crystals, 70% yield. 31P{1H} NMR: δ 50.4 (s with 195Pt satellites,
1
1JPtP ) 3116 Hz, dppe). H NMR: δ 7.78-7.41 (m, 20H, Ph of
dppe), 2.41 (br, 4H, CH2 of dppe), 1.79 (s, 15H, Cp*). IR (cm-1):
1534 (νNO). Anal. Calcd for C37H41Cl2MoNOP2PtS2: C, 44.27; H,
4.12; N, 1.40. Found: C, 44.10; H, 4.15; N, 1.37.
5b·C2H4Cl2: recrystallized from C2H4Cl2-hexane, brown crys-
tals, 46% yield. 31P{1H} NMR: δ 46.4 (s with 195Pt satellites, 1JPtP
1
) 3194 Hz, dppe). H NMR: δ 7.76-7.43 (m, 20H, Ph of dppe),
2.45 (br, 4H, CH2 of dppe), 1.85 (s, 15H, Cp*). IR (cm-1): 1497
(νNO). Anal. Calcd for C38H43Cl2NOP2PtS2W: C, 41.28; H, 3.92;
N, 1.27. Found: C, 41.19; H, 3.97; N, 1.27.
9a: brown solid, 81% yield. IR (cm-1): 1597 (νNO). Anal. Calcd
for C23H39F6MoNOP2RhS2: C, 35.21; H, 5.01; N, 1.79. Found: C,
35.20; H, 4.97; N, 1.52.
Preparation of [(dppp)Pt(µ-S)2M′(NO)Cp*] (6a, M′ ) Mo;
6b, M′
) W). These complexes were synthesized from
10a: brown solid, 84% yield. IR (cm-1): 1591 (νNO). Anal. Calcd
for C23H39F6IrMoNOP2S2: C, 31.61; H, 4.50; N, 1.60. Found: C,
31.75; H, 4.79; N, 1.44.
[Pt(SH)2(dppp)] and 1a or 1b by a procedure similar to that
described for 4a except that CH2Cl2 was used as the eluent for
alumina column chromatography. 6a: green solids, 83% yield.
1
31P{1H} NMR: δ -4.0 (s with 195Pt satellites, JPtP ) 3056 Hz,
10b: dark-green crystals, 97% yield. IR (cm-1): 1578 (νNO). Anal.
Calcd for C23H39F6IrNOP2S2W: C, 28.73; H, 4.09; N, 1.46. Found:
C, 28.91; H, 4.03; N, 1.30.
1
dppp). H NMR: δ 7.65-7.37 (m, 20H, Ph of dppp), 2.61-2.53
(br, 4H, CH2 of dppp), 2.14-1.84 (br, 2H, CH2 of dppp), 1.63 (s,
4266 Inorganic Chemistry, Vol. 47, No. 10, 2008

Heterodinuclear Nitrosyl Complexes
Preparation of [Cp*M(PMe3)(µ-S)2W(NOR)Cp*][OTf] (11,
M ) Rh, R ) Me; 12, M ) Ir, R ) Me; 13, M ) Rh, R )
Et; 14, M ) Ir, R ) Et). The following procedure for the
preparation of [Cp*Rh(PMe3)(µ-S)2W(NOMe)Cp*][OTf] (11; OTf
) OSO2CF3) is representative. To a dark-green solution of 2b (160
mg, 0.220 mmol) in CH2Cl2 (10 mL) was added MeOTf (25 µL,
0.22 mmol) at -40 °C, and the resultant red solution was gradually
warmed to room temperature. The solution was stirred overnight
and dried in vacuo. The dark-red residue was recrystallized from
CH2Cl2-hexane (5 mL-10 mL) to afford 11 as a red solid (179
mg, 0.201 mmol, 91% yield). 31P{1H} NMR: δ 8.1 (d, 1JRhP ) 142
Hz, PMe3). 1H NMR: δ 4.06 (s, 3H, NOMe), 2.18 (s, 15H, Cp*W),
1.93 (d, 4JPH ) 2.9 Hz, 15H, Cp*Rh), 1.31 (d, 2JPH ) 11.2 Hz, 9H,
PMe3). Anal. Calcd for C25H42F3NO4PRhS3W: C, 33.68; H, 4.75;
N, 1.57. Found: C, 33.50; H, 4.81; N, 1.54. Single crystals of
[Cp*Rh(PMe3)(µ-S)2W(NOMe)Cp*][PF6] (11′) suitable for X-ray
crystallography were obtained by the anion metathesis of 11 with
nBu4NPF6 and further recrystallization from CH2Cl2-hexane.
12: orange crystals, 95% yield. 31P{1H} NMR: δ -25.3 (s,
was recrystallized from CH2Cl2-hexane to afford 17·CH2Cl2 as
orange crystals (40.0 mg, 0.034 mmol, 75%). 31P{1H} NMR: δ
-9.1 (d with 195Pt satellites, JPP ) 32 Hz, 1JPtP ) 3054 Hz, dppp),
-13.6 (d with 195Pt satellites, JPP ) 32 Hz, 1JPtP ) 2884 Hz, dppp).
1H NMR: δ 7.68-7.29 (m, 20H, Ph of dppp), 3.53-3.45,
3.29-3.22 (m, 1H each, CH2 of dppp), 2.90-2.81 (m, 2H, CH2 of
dppp), 2.63-2.50 (br, 2H, CH2 of dppp), 2.22 (d with 195Pt satellites,
4JPH ) 3.5 Hz, 3JPtH ) 34.0 Hz, 3H, SMe), 1.76 (s, 15H, Cp*). IR
(cm-1): 1603 (νNO). Anal. Calcd for C40H46Cl2F3MoNO4P2PtS3: C,
40.65; H, 3.92; N, 1.19. Found: C, 40.51; H, 3.87; N, 1.13.
Reaction of 6b with MeOTf. MeOTf (1 equiv) was added to a
solution of 6b in CH2Cl2 at -60 °C to afford a mixture of the
S-methylated complex [(dppp)Pt(µ-SMe)(µ-S)W(NO)Cp*](OTf)
(18) and the O-methylated complex [(dppp)Pt(µ-S)2W(NOMe)-
1
Cp*](OTf) (19) (ca. 2:1, determined by 31P{1H} and H NMR).
These complexes could not be separated but were characterized
spectroscopically.
18. 31P{1H} NMR: δ -9.4 (d with 195Pt satellites, JPP ) 30 Hz,
1JPtP ) 3098 Hz, dppp), -13.8 (d with 195Pt satellites, JPP ) 30
Hz, 1JPtP ) 2970 Hz, dppp). 1H NMR: δ 2.36 (br, 3H, SMe), 1.86
(s, 15H, Cp*). IR (cm-1): 1602 (νNO).
1
PMe3). H NMR: δ 4.02 (s, 3H, NOMe), 2.20 (s, 15H, Cp*W),
1.94 (d, 4JPH ) 1.2 Hz, 15H, Cp*Ir), 1.41 (d, 2JPH ) 11.2 Hz, 9H,
1
PMe3). Anal. Calcd for C25H42F3IrNO4PS3W: C, 30.61; H, 4.32;
19. 31P{1H} NMR: δ -8.9 (s with 195Pt satellites, JPtP ) 3088
1
N, 1.43. Found: C, 30.37; H, 4.32; N, 1.50.
Hz, dppp). H NMR: δ 3.77 (s, 3H, NOMe), 1.93 (s, 15H, Cp*).
1
13: red crystals, 53% yield. 31P{1H} NMR: δ 9.3 (d, JRhP
)
Preparation of [Cp*M(PMe3)(µ-S)2W(O)Cp*](OTf) (20, M
) Rh; 21, M ) Ir). The following procedure for the preparation
of [Cp*Rh(PMe3)(µ-S)2W(O)Cp*][OTf] (20) is representative. To
a dark-green solution of 2b (53.0 mg, 0.073 mmol) in CH2Cl2 (5
mL) was added HOTf (13 µL, 0.15 mmol) at -40 °C, and the
resultant red solution was gradually warmed to room temperature.
The solution was stirred overnight and was dried in vacuo. The
residual red oil was recrystallized from CH2Cl2 (2 mL)-Et2O (20
mL) to afford 20 as orange needles (47.3 mg, 0.055 mmol, 75%
yield). 31P{1H} NMR: δ 8.7 (d, 1JRhP ) 140 Hz, PMe3). 1H NMR:
3
143 Hz, PMe3). 1H NMR: δ 4.27 (q, JHH ) 6.4 Hz, 2H,
4
NOCH2CH3), 2.16 (s, 15H, Cp*W), 1.92 (d, JPH ) 2.7 Hz, 15H,
Cp*Rh), 1.30 (m, 12H, PMe3 and NOCH2CH3). Anal. Calcd for
C26H44F3NO4PRhS3W: C, 34.49; H, 4.90; N, 1.55. Found: C, 34.44;
H, 5.01; N, 1.52.
14: brown crystals, 84% yield. 31P{1H} NMR: δ -25.5 (s, PMe3).
3
1H NMR: δ 4.21 (q, JHH ) 7.0 Hz, 2H, NOCH2CH3), 2.16 (s,
15H, Cp*W), 1.91 (d, 4JPH ) 1.0 Hz, 15H, Cp*Ir), 1.37 (d, 2JPH
11.0 Hz, 9H, PMe3), 1.26 (t, JHH ) 7.0 Hz, 3H, NOCH2CH3).
Anal. Calcd for C26H44F3IrNO4PS3W: C, 31.39; H, 4.46; N, 1.41.
Found: C, 31.00; H, 4.34; N, 1.38.
)
3
4
δ 2.22 (s, 15H, Cp*W), 2.00 (d, JPH ) 2.5 Hz, 15H, Cp*Rh),
1.39 (d, 2JPH ) 11.5 Hz, 9H, PMe3). IR (cm-1): 909 (νWdO). Anal.
Calcd for C24H39F3O4PRhS3W: C, 33.42; H, 4.56. Found: C, 33.40;
H, 4.60. Single crystals of [Cp*Rh(PMe3)(µ-S)2W(O)Cp*][BPh4]
(20′) suitable for X-ray crystallography were obtained by the anion
metathesis of 20 with NaBPh4 and further recrystallization from
CH2Cl2-Et2O.
Preparation of [Cp*M(PMe3)(µ-SMe)(µ-S)Mo(NO)Cp*]-
[BPh4] (15, M ) Rh; 16, M ) Ir). The following procedure for
the preparation of [Cp*Rh(PMe3)(µ-SMe)(µ-S)Mo(NO)Cp*][BPh4]
(15) is representative. To a dark-green solution of 2a (37 mg, 0.058
mmol) in CH2Cl2 (5 mL) was added MeOTf (6.6 µL, 0.058 mmol)
at -40 °C, and the mixture was stirred at room temperature for
5 h. The resultant dark-red solution was evaporated to dryness, and
NaBPh4 (ca. 20 mg) and CH2Cl2 (5 mL) were added to the residual
solid. The mixture was filtered, and Et2O (10 mL) was added to
the concentrated filtrate (4 mL). Dark-red crystals of 15 were
gradually formed upon standing at room temperature for 2 weeks,
21: yellow needles, 51% yield. 31P{1H} NMR: δ -22.7 (s,
4
PMe3). 1H NMR: δ 2.23 (s, 15H, Cp*W), 2.02 (d, JPH ) 1.5 Hz,
15H, Cp*Ir), 1.46 (d, 2JPH ) 11.5 Hz, 9H, PMe3). IR (cm-1): 910
(νWdO). Anal. Calcd for C24H39F3IrO4PS3W: C, 30.29; H, 4.13.
Found: C, 30.13; H, 4.02.
Magnetic Moment Measurements. The ambient-temperature
solution magnetic moment of 9b was measured by the Evans
method.13 A CD2Cl2 solution of 9b with known concentration (6.8
mM) was prepared and placed in an NMR tube. A 1H NMR
spectrum was first recorded, and then a coaxial reference capillary
filled with pure CD2Cl2 was inserted inside the sample tube. A
second 1H NMR spectrum, which clearly showed the original and
the paramagnetically shifted deuterated solvent peaks, was thus
obtained. The magnetic moment was calculated using equations
and parameters cited in ref 14.
which were collected by filtration and washed with hexane (30.0
1
mg, 0.031 mmol, 53% yield). 31P{1H} NMR: δ 12.5 (d, JRhP
)
1
135 Hz, PMe3). H NMR: δ 2.58 (s, 3H, SMe), 1.90 (s, 15H,
4
2
Cp*Mo), 1.74 (d, JPH ) 3.2 Hz, 15H, Cp*Rh), 0.94 (d, JPH
)
11.5 Hz, 9H, PMe3). IR (cm-1): 1573 (νNO). Anal. Calcd for
C48H62BMoNOPRhS2: C, 59.20; H, 6.42; N, 1.44. Found: C, 59.07;
H, 6.48; N, 1.39.
16: brown crystals, 54% yield. 31P{1H} NMR: δ -24.4 (s, PMe3).
1H NMR: δ 2.68 (s, 3H, SMe), 2.01 (d, 4JPH ) 1.5 Hz, 15H, Cp*Ir),
2
X-ray Diffraction Studies. Diffraction data for 2b, 4a·CH2Cl2,
9b, 11′, 15, and 20′ were collected on a Rigaku AFC-7S four-
1.93 (s, 15H, Cp*Mo), 1.36 (d, JPH ) 11.5 Hz, 9H, PMe3). IR
(cm-1): 1572 (νNO). Anal. Calcd for C48H62BIrMoNOPS2: C, 54.23;
H, 5.88; N, 1.32. Found: C, 54.20; H, 6.24; N, 1.20.
(13) Evans, D. F. J. Chem. Soc. 1959, 2003–2005.
Preparation of [(dppp)Pt(µ-SMe)(µ-S)Mo(NO)Cp*][OTf] ·
CH2Cl2 (17·CH2Cl2). MeOTf (8.0 mg, 0.049 mmol) was added
to a solution of 6a (42.0 mg, 0.045 mmol) in CH2Cl2 (5 mL) at
-60 °C. The mixture was stirred overnight at room temperature,
and then the volatiles were removed in vacuo. The brown residue
(14) (a) Chufán, E. E.; Verani, C. N.; Puiu, S. C.; Rentschler, E.;
Schatzschneider, U.; Incarvito, C.; Rheingold, A. L.; Karlin, K. D.
Inorg. Chem. 2007, 46, 3017–3026. (b) O’Connor, C. J. Progress in
Inorganic Chemistry; John Wiley & Sons Inc.: New York, 1982; Vol.
29; pp 203-283. (c) Lide, D. R., Ed. CRC Handbook of Chemistry
and Physics, 86th ed.; CRC Press: Boca Raton, FL, 2005.
Inorganic Chemistry, Vol. 47, No. 10, 2008 4267

Arashiba et al.
Table 1. X-ray Crystallographic Data for 2b, 4a·CH2Cl2, 6a, and 7b·MeCN
2b
4a ·CH2Cl2
6a
7b ·MeCN
chemical formula
fw
C23H39NOPRhS2W
727.42
C37H41Cl2MoNOP2PdS2
915.05
C37H41MoNOP2PtS2
932.83
C44H46N2OP2PdS2W
1035.18
dimens of crystals
cryst syst
space group
a, Å
0.60 × 0.30 × 0.30
monoclinic
P21/n
0.50 × 0.30 × 0.30
monoclinic
P21/n
0.20 × 0.20 × 0.20
orthorhombic
Pbca
0.20 × 0.20 × 0.20
orthorhombic
Pnma
17.008(2)
22.457(4)
18.643(4)
19.175(4)
b, Å
18.843(2)
15.578(5)
15.995(3)
17.553(4)
c, Å
17.127(2)
23.520(5)
23.338(5)
12.300(3)
R, deg
, deg
97.121(8)
105.15(2)
γ, deg
V, Å3
5446(1)
8
1.774
2864
50.57
0.164-0.219
5-55
13 308
12 486
8566
7942(3)
8
1.530
6959(3)
8
1.781
4140(2)
4
1.661
Z
F
calcd, g cm-3
F(000)
3696
3680
2056
µ, cm-1
11.180
0.546-0.715
5-55
18 718
18 261
7227
930
0.048
0.050
1.001
46.030
0.261-0.398
5-55
47 349
7986
2413
447
0.035
0.035
34.287
0.388-0.504
5-55
29 676
4897
2993
281
0.021
0.025
transmn factor range
2θ range, deg
no. of reflns measd
no. of unique reflns
no. of reflns used [I > 3σ(I)]
no. of param refined
R [I > 3σ(I)]a
620
0.037
0.038
1.012
+0.81/-1.60
2
Rw [I > 3σ(I)]b
GOF [I > 3σ(I)]c
max diff peak/hole, e Å-3
1.004
+1.90/-0.81
1.004
+1.54/-0.61
+0.48/-0.44
a R ) ∑|Fo| - |Fc|/∑|Fo|. b Rw ) [∑w(|Fo| - |Fc|)2/∑wFo ]1/2, w ) [pFo2 + qσ(Fo ) + r]-1 [p ) 0.0001 (2b and 6a), 0.0003 (4a·CH2Cl2), 0 (7b·MeCN);
2
c
q ) 1.2 (2b), 1.55 (4a·CH2Cl2), 0.55 (6a), 0.35 (7b·MeCN); r ) 0.25 (2b), 0 (4a·CH2Cl2, 6a, and 7b·MeCN)]. GOF ) [∑w(|Fo| - |Fc|)2/(Nobs
-
Nparams)]1/2
.
circle automated diffractometer (crystal-to-detector distance 235
mm) with graphite-monochromated Mo KR radiation (λ ) 0.710 69
Å) at room temperature using the ω-2θ scan technique. Diffraction
data for 6a and 7b·MeCN were collected on a Rigaku Mercury
CCD area detector (crystal-to-detector distance 45 mm) with
graphite-monochromated Mo KR radiation (λ ) 0.710 69 Å) at
-150 °C. Cell parameters were determined by least-squares
refinement of 25 machine-centered reflections for 2b, 4a·CH2Cl2,
9b, 11′, 15, and 20′ or of reflections among 5 < 2θ < 55° for 6a
and 7b·MeCN. Intensity data were corrected for empirical absorp-
tions (Ψ scans for 2b, 4a·CH2Cl2, 9b, 11′, 15, and 20′; REQAB
for 2b, 4a·CH2Cl2, 9b, 11′, and 15; SHELX-97 for 6a),19 and the
remaining non-H atoms were found by subsequent Fourier synthe-
ses.20 All non-H atoms were refined on Fo [I > 3σ(I)] anisotropi-
cally by full-matrix least-squares techniques, while all the H atoms
were placed at calculated positions with fixed isotropic parameters.
The atomic scattering factors were taken from ref 21. Anomalous
dispersion effects were included in Fc.22 The values of ∆f′ and ∆f′′
were taken from ref 23. Details of the X-ray diffraction study are
summarized in Tables 1 and 2.
Results and Discussion
for 6a and 7b·MeCN) and for Lorentz-polarization effects.15
A
Synthesis and Structure of Group 9-Group 6 Hetero-
dinuclear Complexes 2 and 3. When the bis(hydrosulfido)
complexes of the group 9 metals [Cp*M(SH)2(PMe3)] (M
) Rh, Ir) were allowed to react with an equimolar amount
of the group 6 nitrosyl complexes [Cp*M′Cl2(NO)] (1) in
the presence of 2 equiv of NEt3, the bis(sulfido)-bridged
ELHB complexes [Cp*M(PMe3)(µ-S)2M′(NO)Cp*] (2 and
3) were obtained in good-to-moderate yields (eq 1). The
molybdenum complexes 2a and 3a show one strong IR
correction for secondary extinction was further applied for 2b
[coefficient, 32(5)], 4a·CH2Cl2 [coefficient, 57(8)], 9b [coefficient,
35(4)], 11′ [coefficient, 52(2)], and 20′ [coefficient, 16(2)].16 No
significant decay was observed during the collection of reflections.
The structure solution and refinements were carried out using the
CrystalStructure crystallographic software package.17 The positions
of the heavy atoms were determined by direct methods (SIR92 for
7b·MeCN; SHELX97 for 20′)18 or by Patterson methods (PATTY
(15) Jacobson, R. A. REQAB: priVate communication to Rigaku Corp.;
Rigaku Corp.: Tokyo, Japan, 1998.
(16) Larson, A. C. In Crystallographic Computing: Proceedings of an
International Summer School Organized by The Commission on
Crystallographic Computing of the International Union of Crystal-
lography and Held in Ottawa, August 4-11, 1969; Ahmed, F. R.,
Hall, S. R., Huber, C. P., Eds.; Munksgaard: Copenhagen, Denmark,
1970; pp 291–294.
(19) Beurskens, P. T.; Admiraal, G.; Behm, H.; Beurskens, G.; Bosman,
W. P.; García-Granda, S.; Gould, R. O.; Smits, J. M. M.; Smykalla,
C. Z. Kristallogr., Suppl. 1991, 4, 99.
(20) Beurskens, P. T.; Beurskens, G.; de Gelder. R.; García-Granda, S.;
Gould, R. O.; Israël, R.; Smits, J. M. M. The DIRDIF-99 program
system; Crystallography Laboratory, University of Nijmegen: Nijmegen,
The Netherlands, 1999.
(21) Cromer, D. T.; Waber, J. T. In International Tables for X-ray
Crystallography; Ibers, J. A., Hamilton, W. C., Eds.; Kynoch Press:
Birmingham, England, 1974; Vol. IV, Table 2.2 A.
(22) Ibers, J. A.; Hamilton, W. C. Acta Crystallogr. 1964, 17, 781–782.
(23) (a) Creagh, D. C.; Hubbell, J. H. In International Tables for X-ray
Crystallography; Wilson, A. J. C., Ed.; Kluwer Academic Publishers:
Boston, MA, 1992; Vol. C, Table 4.2.4.3. (b) Creagh, D. C.; McAuley,
W. J. In International Tables for X-ray Crystallography; Wilson,
A. J. C., Ed.; Kluwer Academic Publishers; Boston, MA, 1992; Vol.
C, Table 4.2.6.8.
(17) (a) CrystalStructure 3.60: Single Crystal Structure Analysis Software;
Rigaku Corp.: The Woodlands, TX, 2000–2004. (b) Watkin, D. J.;
Prout, C. K.; Carruthers, J. R.; Betteridge, P. W. CRYSTALS Issue
10; Chemical Crystallography Laboratory: Oxford, U.K., 1996.
(18) (a) Altomare, A.; Cascarano, G.; Giacovazzo, C.; Guagliardi, A.; Burla,
M. C.; Polidori, G.; Camalli, M. J. Appl. Crystallogr. 1994, 27, 435.
(b) Altomare, A.; Burla, M. C.; Camalli, M.; Cascarano, G. L.;
Giacovazzo, C.; Guagliardi, A.; Moliterni, A. G. G.; Polidori, G.;
Spagna, R. J. Appl. Crystallogr. 1999, 32, 115–119. (c) Sheldrick,
G. M. SHELX-97: Program for the Refinement of Crystal Structure;
University of Göttingen: Göttingen, Germany, 1997.
4268 Inorganic Chemistry, Vol. 47, No. 10, 2008

Heterodinuclear Nitrosyl Complexes
Table 2. X-ray Crystallographic Data for 9b, 11′, 15, and 20′
9b
11′
15
20′
chemical formula
fw
C23H39F6NOP2RhS2W
872.38
C24H42F6NOP2RhS2W
887.42
C48H62BMoNOPRhS2
973.77
C47H59BOPRhS2W
1032.64
dimens of crystals
cryst syst
space group
a, Å
b, Å
c, Å
0.50 × 0.40 × 0.30
orthorhombic
Pbcn
17.627(2)
16.322(2)
0.90 × 0.30 × 0.20
monoclinic
P21/c
8.714(3)
24.849(4)
0.40 × 0.40 × 0.20
1.00 × 0.30 × 0.30
triclinic
triclinic
j
j
P1
P1
10.204(1)
18.072(3)
27.000(5)
75.05(1)
88.46(1)
82.92(1)
4773(1)
4
1.355
2016
7.62
0.702-0.859
5-55
22 495
21 897
8584
12.236(1)
17.377(2)
11.669(1)
103.311(8)
94.657(8)
73.725(8)
2317.3(4)
2
1.480
1040
29.953
0.315-0.407
5-55
11 100
10 603
8546
547
0.031
0.032
1.014
+1.61/-1.33
21.780(2)
14.533(2)
R, deg
, deg
91.52(2)
γ, deg
V, Å3
6266(1)
8
1.849
3416
44.87
0.209-0.260
5-55
7890
7201
4151
376
0.036
0.038
1.008
+0.90/-0.52
2
3145(1)
4
1.874
1744
44.71
0.176-0.409
5-55
7875
7213
6041
422
0.030
0.031
1.018
+1.12/-1.26
2
Z
F
calcd, g cm-3
F(000)
µ, cm-1
transmn factor range
2θ range, deg
no. of reflns measd
no. of unique reflns
no. of reflns used [I > 3σ(I)]
no. of param refined
R [I > 3σ(I)]a
1133
0.053
0.054
1.014
Rw [I > 3σ(I)]b
GOF [I > 3 σ(I)]c
max diff peak/hole, e Å-3
+0.60/-0.62
a R ) ∑|Fo| - |Fc|/∑|Fo|. b Rw ) [∑w(|Fo| - |Fc|)2/∑wFo ]1/2, w ) [pFo2 + qσ(Fo ) + r]-1 [p ) 0.0002 (9b), 0.0001 (11′, 15, and 20′); q ) 1.0 (9b), 3.0
c
(11′), 1.1 (15), 1.8 (20′); r ) 0.15 (9b), 0.10 (11′ and 15), 0.30 (20′)]. GOF ) [∑w(|Fo| - |Fc|)2/(Nobs - Nparams)]1/2
.
Table 3. Selected Bond Lengths (Å) and Angles (deg) for 2b
molecule 1 molecule 2
absorption assignable to the NO stretching around 1520 cm-1
and the tungsten congeners 2b and 3b at 1490 cm-1. These
ν(NO) values are among the lowest for linear nitrosyl
complexes and suggest the existence of strong M′fNO back-
bonding.24 Particularly noteworthy is the large red shift from
the mononuclear thiolato complexes [Cp*M′(NO)(SPh)2]
[ν(NO) ) 1631 (M′ ) Mo), 1609 (M′ ) W) cm-1],25 which
mimic the coordination environment of 2 and 3 except for
the neighboring rhodium or iridium center. We thus attribute
the strong π back-bonding primarily to the influx of electrons
from the group 9 metal center through the MIII fM′II dative
bond.26 The 1H NMR spectra display a set of signals due to
two distinct Cp* ligands and one PMe3 ligand, being well
in accordance with the formulation.
W1-Rh1
W1-S1
W1-S2
W1-N1
W1-C1
W1-C2
W1-C3
W1-C4
W1-C5
Rh1-S1
Rh1-S2
N1-O1
2.9149(6)
2.331(2)
2.327(2)
1.754(6)
2.337(7)
2.355(8)
2.538(8)
2.551(8)
2.375(7)
2.390(2)
2.394(2)
1.244(9)
W2-Rh2
W2-S3
2.8986(6)
2.342(2)
2.330(2)
1.746(6)
2.338(8)
2.353(8)
2.525(8)
2.531(8)
2.343(8)
2.396(2)
2.385(2)
1.255(9)
W2-S4
W2-N2
W2-C24
W2-C25
W2-C26
W2-C27
W2-C28
Rh2-S3
Rh2-S4
N2-O2
W1-S1-Rh1
W1-S2-Rh1
W1-N1-O1
76.25(6)
76.24(6)
169.8(5)
W2-S3-Rh2
W2-S4-Rh2
W2-N2-O2
75.44(6)
75.86(6)
170.1(5)
of 2b. As mentioned above, this electron donation between
the metal atoms is responsible for the electron-rich nature
of the WII center. Enhancement of the π donation of the
bridging S atoms by the Rh atom is not evident, because the
(24) (a) Hayton, T. W.; Legzdins, P.; Patrick, B. O. Inorg. Chem. 2002,
41, 5388–5396. (b) Müller, A.; Eltzner, W.; Clegg, W.; Sheldrick,
G. M. Angew. Chem., Int. Ed. Engl. 1982, 21, 536–537. (c) Chen, Z.;
Schmalle, H. W.; Fox, T.; Berke, H. Dalton Trans. 2005, 580–587.
(25) Jin, G.-X.; Herberhold, M. Transition Met. Chem. 2001, 26, 445–
447.
The molecular structure of 2b has been established by an
X-ray diffraction study (Table 3). The unit cell contains two
independent but very similar complex molecules, one of
which is shown in Figure 1. Both rhodium and tungsten
centers adopt a three-legged piano-stool geometry. The two
Cp* ligands occupy mutually trans positions with respect to
the RhWS2 ring. Within the RhWS2 core, the short Rh-W
distance (2.91 Å, mean) as well as the acute Rh-S-W
angles (75.9°, mean) clearly indicates the presence of a dative
bond from RhIII to WII in agreement with the 34e structure
(26) In complexes 2 and 3, the π donation from the S atoms to the
molybdenum/tungsten center is considered to be stronger than that in
[Cp*M′(NO)(SPh)2] (M′ ) Mo, W) because of the four-electron
repulsion from the 18e rhodium/iridium center, and this effect may
also be responsible to the low νNO values of 2 and 3 (see ref 27).
However, as described below, the W-S bond distances in 2b are not
as exceptional as 16e WII-S bonds. Therefore, we believe that the
Rh/Ir f Mo/W dative bond plays the major role in the increase of
the electron density at the Mo/W center.
(27) (a) Fox, D. C.; Fiedler, A. T.; Halfen, H. L.; Brunold, T. C.; Halfen,
J. A. J. Am. Chem. Soc. 2004, 126, 7627–7638. (b) Galindo, A.; Mealli,
C.; Cuyás, J.; Miguel, D.; Riera, V.; Pérez-Martínez, J. A.; Bois, C.;
Jeannin, Y. Organometallics 1996, 15, 2735–2744.
Inorganic Chemistry, Vol. 47, No. 10, 2008 4269

Arashiba et al.
W-S distances in 2b (2.33 Å) are comparable with those in
the related mononuclear polysulfido complex [Cp*W-
(NO)(S5)] (2.33 Å).28 It should also be mentioned that the
two W-C bonds trans to the nitrosyl ligand (2.53-2.55 Å)
are meaningfully longer than the other three W-C bonds
(2.34-2.37 Å), although the Cp* protons are indistinguish-
able in the 1H NMR spectrum even at -90 °C. We consider
that the increased electron density of the tungsten center, in
combination with the trans influence of the nitrosyl ligand,29
causes the displacement of the Cp* ligand on the W atom
from the symmetrical η5-coordination.30 Despite the electron
richness of the tungsten center and the consequent strong π
back-donation, the structure of the W-N-O moiety is not
exceptional as a linear nitrosyl ligand.
Figure 1. Molecular structure of 2b. One of the two crystallographically
independent components in the crystal is shown. Thermal ellipsoids are
shown at the 50% probability level. H atoms are omitted for clarity.
Synthesis and Structure of Group 10-Group 6 Hetero-
dinuclear Complexes 4-8. When the group 10 bis(hydro-
sulfido) complexes [L2M(SH)2] (L2 ) dppe, dppp, dpmb;
M ) Pd, Pt) were used as templates to react with 1, a series
of group 10-group 6 ELHB complexes [(dppe)M(µ-
S)2M′(NO)Cp*] (4 and 5), [(dppp)Pt(µ-S)2M′(NO)Cp*] (6),
and [(dpmb)M(µ-S)2M′(NO)Cp*] (7 and 8) were obtained
in good-to-moderate yields (eq 2). In the IR spectra, an NO
stretching is observed at around 1530 cm-1 for the molyb-
denum complexes 4a-8a and 1500 cm-1 for the tungsten
complexes 4b-8b. The lowest νNO values are observed for
M(dpmb)-W complexes 7b and 8b at around 1480 cm-1
1
(overlapping with a νPPh band). The H and 31P{1H} NMR
spectra of 4-8 are consistent with the formulation and
indicative of a Cs symmetrical structure.
Figure 2. Molecular structure of 4a·CH2Cl2. One of the two crystallo-
graphically independent molecules in the crystal is shown. Thermal ellipsoids
are shown at the 50% probability level. H atoms are omitted for clarity.
Table 4. Selected Bond Lengths (Å) and Angles (deg) for 4a·CH2Cl2
molecule 1
molecule 2
Mo1-Pd1
Mo1-S1
Mo1-S2
Mo1-N1
Mo1-C1
Mo1-C2
Mo1-C3
Mo1-C4
Mo1-C5
Pd1-S1
Pd1-S2
N1-O1
2.9142(10)
2.335(2)
2.327(2)
1.772(7)
2.311(12)
2.341(10)
2.457(9)
2.470(9)
2.403(11)
2.364(2)
2.364(2)
1.223(9)
Mo2-Pd2
Mo2-S3
Mo2-S4
Mo2-N2
Mo2-C38
Mo2-C39
Mo2-C40
Mo2-C41
Mo2-C42
Pd2-S3
2.9149(10)
2.327(2)
2.329(2)
1.761(7)
2.320(11)
2.391(12)
2.475(10)
2.466(9)
2.328(9)
2.355(2)
2.353(2)
1.228(9)
Pd2-S4
N2-O2
The detailed molecular structure of 4a has been
determined by X-ray crystallography (Figure 2 and Table
4). The unit cell contains two crystallographically inde-
pendent molecules, but their structures are essentially the
same. The Pd atom has a square-planar geometry, and the
PdMoS2 core is slightly puckered where the dihedral angle
between the PdS2 and MoS2 planes is 165.3°. On the other
Mo1-S1-Pd1
Mo1-S2-Pd1
Mo1-N1-O1
P1-Pd1-P2
P1-Pd1-S1
P2-Pd1-S2
S1-Pd1-S2
76.65(8)
76.81(8)
170.1(7)
86.15(9)
84.82(9)
87.79(9)
101.24(9)
Mo2-S3-Pd2
Mo2-S4-Pd2
Mo2-N2-O2
P3-Pd2-P4
P3-Pd2-S3
P4-Pd2-S4
S3-Pd2-S4
77.01(8)
77.01(8)
169.5(7)
85.76(9)
88.01(9)
84.54(9)
101.69(9)
(28) Herberhold, M.; Jin, G.-X.; Kremnitz, W.; Rheingold, A. L.; Haggerty,
B. S. Z. Naturforsch. B: Chem. Sci. 1991, 46b, 500–506.
(29) Gomez-Sal, P.; de Jesu´s, E.; Michiels, W.; Royo, P.; Vázque de Miguel,
A.; Martínez-Carrera, S. J. Chem. Soc., Dalton Trans. 1990, 2445–
2449.
hand, the structure of the molybdenum center is closely
related to that of the tungsten center in 2b except that the
displacement of the Cp* ligand from η5 coordination is
not as remarkable as that in 2b. The separation of Pd-Mo
(2.91 Å, mean) and the acute angle of Pd-S-Mo (76.9°,
mean) suggest the presence of a dative bond from PdII to
MoII.
(30) (a) The electron-rich metal centers in the formally 20e complexes
[Cp2Mo(NO)Me] and [Cp*2Mo(N)(N3)] are known to reduce the
hapticity of the Cp ligands to a greater extent. Cotton, F. A.; Rusholme,
G. A. J. Am. Chem. Soc. 1972, 94, 402–406. (b) Shin, J. H.;
Bridgewater, B. M.; Churchill, D. G.; Baik, M.-H.; Friesner, R. A.;
Parkin, G. J. Am. Chem. Soc. 2001, 123, 10111–10112.
4270 Inorganic Chemistry, Vol. 47, No. 10, 2008

Heterodinuclear Nitrosyl Complexes
Figure 3. Molecular structures of 6a (a) and 7b·MeCN (b). Thermal ellipsoids are shown at the 50% probability level. H atoms are omitted for clarity.
Table 5. Selected Bond Lengths (Å) and Angles (deg) for 6a and
7b·MeCN
Table 6. Cyclic Voltammetry Data for the Oxidation Potentials of
Complexes 2-8
a
6a
7b ·MeCN
compound
E1/2
ip,c/ip,a
Mo1-Pt1
Mo1-S1
Mo1-S2
Mo1-N1
Mo1-C1
Mo1-C2
Mo1-C3
Mo1-C4
Mo1-C5
Pt1-S1
2.9189(12)
2.329(3)
2.317(3)
1.764(11)
2.467(15)
2.417(13)
2.331(13)
2.309(14)
2.432(15)
2.377(3)
W1-Pd1
W1-S1
W1-N1
W1-C1
W1-C2
W1-C3
Pd1-S1
N1-O1
2.9565(5)
2.3101(10)
1.763(4)
2.339(3)
2.441(4)
2.483(5)
2.3833(11)
1.244(6)
2a
3a
4a
5a
6a
7a
8a
2b
3b
4b
5b
6b
7b
8b
+0.24
+0.22
+0.39
+0.39
+0.37
+0.41
+0.41
+0.13
+0.12
+0.32
+0.31
+0.30
+0.29
+0.31
1.27
1.18
0.69
0.92
0.94
0.73
0.81
1.30
0.94
0.92
0.99
0.96
0.91
1.01
Pt1-S2
2.365(3)
1.226(15)
N1-O1
Mo1-S1-Pt1
Mo1-S2-Pt1
Mo1-N1-O1
P1-Pt1-P2
76.66(10)
77.13(10)
172.5(9)
W1-S1-Pd1
W1-N1-O1
P1-Pd1-P1*
S1-Pd1-S1*
P1-Pd1-S1
78.07(3)
174.9(4)
103.24(4)
96.77(4)
79.95(3)
a vs SCE, reversible.
98.55(13)
that of the group 6 metal center. The chelate size of the
diphosphine in complexes 4-8 has little effect on the
oxidation potentials. No notable reduction waves are ob-
served in the range down to -1.5 V. These results make a
sharp contrast with the redox behavior of the parent mono-
nuclear group 6 nitrosyl complexes [Cp*M′X2(NO)] (M′ )
Mo, X ) Cl, Br, I; M′ ) W, X ) I), for which a reversible
single-electron reduction at -0.3 to -0.5 V has been
reported.31 In the present ELHB complexes, the flux of
electrons from the neighboring late metal center obviously
increases the electron density at the group 6 metal center
and facilitates its oxidation. It is also interesting to note that
the group 9-group 6 complexes 2 and 3 are oxidized at
lower potentials by about 0.17 V than the group 10-group
6 complexes 4-8 in spite of the lower oxidation state of the
group 10 metals. We consider that the formal 18e structure
of the RhIII/IrIII center in 2 and 3 contributes to the more
effective electron donation than the formal 16e PdII/PtII center
in 4-8.
The molecular structures of (dppp)Pt-Mo complex 6a and
(dpmb)Pd-W complex 7b were also confirmed by crystal-
lographic studies (Figure 3 and Table 5). Complex 7b has a
crystallographic mirror plane containing the Pd1, W1, N1,
O1, and C3 atoms. The total coordination geometries of 6a
and 7b are similar to that of 4a, but the difference in the
phosphine chelate ring size gives rise to the slight deforma-
tion of the core structure. Unlike 4a, the PtMoS2 atoms in
6a are almost coplanar, while the P2S2 coordination arrange-
ment around the platinum center is distorted from planarity,
where the PtP2 plane is skewed by 13.9° from the PtS2 plane.
On the other hand, the palladium center in 7b adopts almost
a planar geometry, while the PdWS2 core is considerably
puckered (159.1°). In all cases, the nitrosyl ligands keep the
linear coordination mode.
Electrochemical Properties of 2-8. The electron-rich
nature of the group 6 metal centers in 2-8 was further
demonstrated by cyclic voltammetry measurements. As
shown in Table 6, complexes 2-8 undergo reversible single-
electron oxidations. The dinuclear complexes containing
molybdenum are oxidized at 0.22-0.24 V (for the group 9
metal complexes) or 0.37-0.41 V (for the group 10 metal
complexes) vs SCE and those containing tungsten at
0.12-0.13 V (for the group 9 metal complexes) or 0.29-0.31
V (for the group 10 metal complexes). Because the potentials
are governed by the group 6 metals regardless of the group
9 and 10 metals, the oxidation could be ascribed mainly to
One-Electron Oxidation of 2 and 3. On the basis of the
electrochemical behavior of 2-8, we next examined isolation
of the one-electron-oxidation products. Treatment of 2 and
3 with [Cp2Fe][PF6] afforded the cationic complexes [Cp*M-
(PMe3)(µ-S)2M′(NO)Cp*][PF6] (9 and 10) in excellent yield
(eq 3). Extremely broadened 1H NMR spectra clearly indicate
the paramagnetic nature of 9 and 10. Complex 9b exhibits
(31) Herring, F. G.; Legzdins, P.; Richter-Addo, G. B. Organometallics
1989, 8, 1485–1493.
Inorganic Chemistry, Vol. 47, No. 10, 2008 4271

Arashiba et al.
Figure 4. Molecular structure of the cationic part of 9b. Thermal ellipsoids
Figure 5. Molecular structure of the cationic part of 11′. Thermal ellipsoids
are shown at the 50% probability level. H atoms are omitted for clarity.
Selected bond lengths (Å) and angles (deg): W1-Rh1 2.9096(3), W1-S1
2.297(1), W1-S2 2.303(1), W1-N1 1.747(4), Rh1-S1 2.388(1), Rh1-S2
2.398(1), N1-O1 1.350(6), O1-C11 1.436(7), W1-S1-Rh1 76.74(4),
W1-S2-Rh1 76.46(4), W1-N1-O1 164.0(3), N1-O1-C11 112.3(4).
are shown at the 50% probability level. H atoms are omitted for clarity.
Table 7. Selected Bond Lengths (Å) and Angles (deg) for 9b
W1-Rh1
W1-S1
W1-S2
W1-N1
W1-C1
W1-C2
2.8833(6)
2.2780(19)
2.284(2)
1.796(7)
2.404(7)
2.384(7)
W1-C3
W1-C4
W1-C5
Rh1-S1
Rh1-S2
N1-O1
2.358(8)
2.364(8)
2.368(7)
2.370(2)
2.383(2)
1.222(10)
characterized by the absence of IR absorptions ascribable to
1
the NO multiple bond and a new H NMR resonance for
the alkoxy group. The detailed structure of [Cp*Rh(PMe3)(µ-
S)2W(NOMe)Cp*](PF6) (11′), which is obtained by the anion
metathesis of 11 with [Bu4N][PF6], has been unambiguously
determined by an X-ray crystallographic study (Figure 5).
The W-N-O moiety is essentially linear [164.0(3)°], being
diagnostic of the four-electron donor character of the
alkoxyimido ligand. The metrical parameters of the alkoxy-
imido ligand in 11′ are comparable to those in
[CpNbCl2(NOBut)], which was derived from an O-tert-
butylhydroxylamine salt.32 It should be mentioned that
electrophilic methylation of a genuine terminal nitrosyl ligand
has not been described in the literature. The closest example
to the present reaction is the methylation of the anionic
nitrosyl complex [Cp*MoMe3(NO)Li(thf)2]2, giving the
methoxyimido complex [Cp*MoMe3(NOMe)].33 The Mo-
N-O-Li array in the former lithiated complex, however,
has been revealed to be a bridging oxoimido ligand on the
basis of X-ray crystallography [Mo-N, 1.742(2) Å; N-O,
1.279(3) Å] and IR spectroscopy (νNO ) 1399 cm-1). On
the other hand, the µ-NO ligands are known to be more
activated toward electrophilic attack, and several examples
of their methylation have been documented.34
W1-S1-Rh1
W1-S2-Rh1
76.66(6)
76.28(6)
W1-N1-O1
167.4(6)
µeff ) 1.87 (Evans NMR method), which is consistent with
an S ) 1/2 system. In good agreement with the oxidation of
the group 6 metal center, 9 and 10 exhibit an NO stretching
band at around 1595 cm-1 (molybdenum complexes) or 1580
cm-1 (tungsten complexes), which is about 100 cm-1 blue-
shifted compared to those for 2 and 3. The molecular
structure of 9b was fully established by an X-ray analysis
(Figure 4 and Table 7). The Rh-W [2.8833(6) Å] and W-S
(2.28 Å, mean) bond distances are slightly shorter than those
of 2b, suggesting oxidation of the tungsten center. On the
other hand, the Cp* ligand at the tungsten center adopts a
normal η5-coordination mode with the approximately equiva-
lent W-C distances (2.36-2.40 Å), which is also consistent
with the lower electron density at the W atom than in 2b. In
contrast to 2 and 3, oxidation of 4-8 with [Cp2Fe][PF6]
resulted in unidentified complex mixtures.
Alkylation of Complexes 2 and 3. As described above,
complexes 2-8 are featured by the strong π back-bonding
to the nitrosyl ligand. We have therefore examined their
reactivities with electrophiles. As expected, treatment of the
M-W complex 2b or 3b with 1 equiv of ROTf (R ) Me,
Et; OTf ) OSO2CF3) in CH2Cl2 selectively afforded the MIII/
WVI alkoxyimido complexes [Cp/M(PMe3)(µ-S)2W(NOR)-
Cp*](OTf) (11-14) through the electrophilic O-alkylation
of the nitrosyl ligand (eq 4). These complexes have been
In contrast to the O-alkylation of 2b and 3b, treatment of
the M-Mo complexes 2a and 3a with MeOTf followed by
(32) Green, M. L. H.; James, J. T.; Sanders, J. F. Chem. Commun. 1996,
1343–1344.
(33) Sharp, W. B.; Daff, P. J.; McNeil, W. S.; Legzdins, P. J. Am. Chem.
Soc. 2001, 123, 6272–6282.
4272 Inorganic Chemistry, Vol. 47, No. 10, 2008

Heterodinuclear Nitrosyl Complexes
Scheme 1
6a with 1 equiv of MeOTf yielded the S-methylated
complex [(dppp)Pt(µ-SMe)(µ-S)Mo(NO)Cp*][OTf] (17)
in 75% yield (eq 5).36 Complex 17 shows two doublets
at δ -9.1 and -13.6 with 195Pt satellites in the 31P{1H}
NMR spectrum as well as one doublet (4JPH ) 3.5 Hz)
with 195Pt satellites at δ 2.22 due to the SMe protons in
1
the H NMR, indicating the methylation of one of the
bridging sulfur ligands. On the other hand, a similar
reaction of Pt-W complex 6b led to a mixture of the
S-methylated complex [(dppp)Pt(µ-SMe)(µ-S)W(NO)-
Cp*][OTf] (18) and the O-methylated complex [(dpp-
p)Pt(µ-S)2W(NOMe)Cp*][OTf] (19) in a ratio of 2:1
(determined by NMR spectra; eq 6).35 Complex 18 has
been unambiguously characterized by the 31P{1H} NMR
resonances at δ -9.4 and -13.8 (d with 195Pt satellites),
the 1H NMR signal at δ 2.36 (br, SMe), and the IR
absorption at 1602 cm-1 (νNO) and 19 by the characteristic
methoxyimido signal at δ 3.77 (s) in the 1H NMR
spectrum. These observations indicate that the group
10-group 6 complexes possess a lower tendency to
undergo the O-alkylation of the nitrosyl ligand than the
group 9-group 6 complexes, which is in full agreement
with the results of the IR and cyclic voltammetry
measurements. Thus, not only the tungsten center, which
forms effective π back-bonding, but also the late metal
center, which boosts the π-electron donation through the
metal-metal bond, are essential for the O-alkylation of
the ELHB nitrosyl complexes.
the anion metathesis with NaBPh4 resulted in selective
formation of the methanethiolato complexes [Cp*M(PMe3)(µ-
SMe)(µ-S)Mo(NO)Cp*][BPh4] (15 and 16; Scheme 1).35
Complex 15 exhibits a νNO band at 1573 cm-1 in the IR
spectrum and a singlet at δ 2.58 attributable to an SMe group.
The former value is about 60 cm-1 blue-shifted in the
reaction, reflecting the cationic nature of the RhMoS2 core.
The S-methylation structure of 15 has further been confirmed
by X-ray analysis (Figure 6 and Table 8). The total
coordination geometry of 15 is comparable to that of 2b
except for the S-Me group, but it should be noted that the
Mo-SMe distance is considerably longer (ca. 0.07 Å) than
the Mo-S(sulfido) distance, while the Rh-SMe and
Rh-S(sulfido) distances are nearly the same. The SMe group
is syn to the nitrosyl ligand, probably to avoid the steric
repulsion with the PMe3 ligand. Judging from the results of
the alkylation of 2 and 3, π back-donation from the more
electron-rich tungsten center is necessary for sufficient
activation of NO toward O-alkylation. This tendency parallels
well with the νNO values and the oxidation potentials of 2
and 3.
Methylation of Pt-M′ Complexes 6. Analogously to the
methylation of 2a and 3a, the reaction of Pt-Mo complex
Reaction of 2b and 3b with HOTf. In addition to the
alkylation reactions, protonation of the ELHB complexes has
been attempted as an electrophilic functionalization of the
nitrosyl ligand. With respect to the protonation of a terminal
Figure 6. Molecular structure of the cationic part of 15. One of the two
crystallographically independent components in the crystal is shown.
Thermal ellipsoids are shown at the 50% probability level. Hydrogen atoms
are omitted for clarity.
(34) (a) Stevens, R. E.; Gladfelter, W. L. J. Am. Chem. Soc. 1982, 104,
6454–6457. (b) Stevens, R. E.; Guettler, R. D.; Gladfelter, W. L. Inorg.
Chem. 1990, 29, 451–456. (c) Barr, M. E.; Bjarnason, A.; Dahl, L. F.
Organometallics 1994, 13, 1981–1991. (d) Lee, K. K. H.; Wong, W. T.
J. Chem. Soc., Dalton Trans. 1996, 1707–1720.
Table 8. Selected Bond Lengths (Å) and Angles (deg) for 15
molecule 1
molecule 2
Mo1-Rh1
Mo1-S1
Mo1-S2
Mo1-N1
Rh1-S1
Rh1-S2
N1-O1
2.940(1)
2.385(3)
2.317(3)
1.76(1)
2.395(3)
2.400(3)
1.22(1)
Mo2-Rh2
Mo2-S3
Mo2-S4
Mo2-N2
Rh2-S3
Rh2-S4
N2-O2
2.940(1)
2.391(2)
2.324(3)
1.758(8)
2.389(2)
2.413(2)
1.21(1)
(35) No thermal interconversion between 15 and Rh–Mo analog of 11 or
18 and 19 has been observed. The S-methylated complexes 15 and
18 decompose at 70 °C in C2H4Cl2 without formation of the
O-methylated complexes, while 11 and 19 are stable at this tempera-
ture.
(36) (a) For S-alkylation of [Pt2(diphosphine)2(µ-S)2] complexes, see:
Chong, S. H.; Henderson, W.; Hor, T. S. A. Dalton Trans. 2007, 4008–
4016. (b) Nova, A.; Gonza´lez-Duarte, P.; Lledo´s, A.; Mas-Ballesté,
R.; Ujaque, G. Inorg. Chim. Acta 2006, 359, 3763–3744, and
references cited therein.
Mo1-S1-Rh1
Mo1-S2-Rh1
Mo1-N1-O1
75.92(9)
77.10(9)
164.9(9)
Mo2-S3-Rh2
Mo2-S4-Rh2
Mo2-N2-O2
75.92(6)
76.71(7)
167.4(9)
Inorganic Chemistry, Vol. 47, No. 10, 2008 4273

Arashiba et al.
of the nitrosyl ligand. Subsequent hydrolysis would lead to
complex 20, but unfortunately nitrogenous products could
not be identified. We must await further investigation to
reveal the mechanism for this reaction.
Conclusion
We have synthesized a series of bis(sulfido)-bridged ELHB
complexes composed of a group 6 metal nitrosyl as the
reaction site and a group 9 or group 10 metal fragment as
the electron pool and demonstrated that the latter unit
increases the electron density on the former through the
metal-metal dative bond. The 18e group 9 MIII center
(Cp*M(PMe3)(µ-S)2) is shown to work as a more efficient
electron donor than the 16e group 10 MII center ((diphos-
phine)M(µ-S)2). Treatment of the Rh/Ir-W complexes 2b
and 3b with ROTf results in the electrophilic O-alkylation
of the terminal nitrosyl ligand owing to the enormous π back-
donation to the nitrosyl ligand assisted by donation from the
late metal center in the ELHB core. In contrast, S-methylation
takes place for the ELHB complexes with less electron-rich
nitrosyl ligands. Further studies on the electrophilic func-
tionalization of nitrosyl and related ligands at the ELHB
complexes are currently underway.
Figure 7. Molecular structure of the cationic part of 20′. Thermal ellipsoids
are shown at the 50% probability level. H atoms are omitted for clarity.
Selected bond lengths (Å) and angles (deg): W1-Rh1 2.8635(4), W1-S1
2.2555(10), W1-S2 2.2700(12), W1-O1 1.723(2), Rh1-S1 2.3884(10),
Rh1-S2 2.3866(14), W1-S1-Rh1 76.08(2), W1-S2-Rh1 75.85(3).
nitrosyl ligand, N-protonation has mainly been reported for
late-transition-metal nitrosyls,37 whereas O-protonation of a
(nitrosyl)tungsten complex has only recently been described
by Legzdins and co-workers.5,38
Treatment of 2b and 3b with excess HOTf (2 equiv) gave
the cationic oxo complexes [Cp*M(PMe3)(µ-S)2W(O)Cp*]-
[OTf] (20 and 21; eq 7). Complexes 20 and 21 were
characterized by NMR, IR, and elemental analyses, and the
detailed structure was confirmed by X-ray analysis of
[Cp*Rh(PMe3)(µ-S)2W(O)Cp*][BPh4] (20′), which is ob-
tained by the anion metathesis of 20 with NaBPh4 (Figure
7). The W-O [1.723(2) Å] and W-S [2.2555(10) and
2.2700(12) Å] distances are similar to those of [Cp*W(O)(µ-
S)2Ru(CH3CN)(PPh3)2][OTf] [W-O 1.727(3) Å, W-S 2.26
Å, mean).39 From the analogy to the alkylation, we presume
that the first step of the above reaction is the O-protonation
Acknowledgment. Financial support by the Ministry of
Education, Culture, Sports, Science and Technology of Japan
and Chuo University (Joint Research Grant) is appreciated.
Supporting Information Available: Crystallographic data for
2b, 4a·CH2Cl2, 6a, 7b·MeCN, 9b, 11′, 15, and 20′ in CIF format.
This material is available free of charge via the Internet at
http://pubs.acs.org.
(37) (a) Farmer, P. J.; Sulc, F. J. Inorg. Biochem. 2005, 99, 166–184. (b)
Melenkivitz, R.; Hillhouse, G. L. Chem. Commun. 2002, 660–661.
(38) Obayashi, E.; Takahashi, S.; Shiro, Y. J. Am. Chem. Soc. 1998, 120,
12964–12965.
(39) Ohki, Y.; Matsuura, N.; Marumoto, T.; Kawaguchi, H.; Tatsumi, K.
J. Am. Chem. Soc. 2003, 125, 7978–7988.
IC702309H
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