Ruthenium derivatives of NiS2N2 complexes as analogues of bioorganometallic reaction centers

Article abstract of DOI:10.1021/om020724e

Recent results from structural biology demonstrate the catalytic significance of Ni(SR)₂L₂ centers attached to a second metal that binds CO, in particular the NiFe hydrogenases and acetyl CoA synthase. In experiments aimed at developing bimetallic derivatives exhibiting an affinity for CO, we have studied Ru(II) derivatives of nickel diaminodithiolates and the reactivity of these complexes toward CO and other small molecules. The reaction of [Cp*Ru(NCMe)₃]OTf and NiS₂N₂ (S₂N₂ = N,N′-bis(2-mercaptoethyl)-N,N′-dimethyl-1,3-diaminoethane) gives [Cp*Ru(NiS₂N₂)]₂(OTf)₂ ([1]₂(OTf)₂), which exists as a monomer-dimer equilibrium in MeCN solution. Crystallographic analysis of [1]₂(OTf)₂ reveals a centrosymmetric dication with the Ru being quasi-octahedral and the NiS₂N₂ coordination sphere being relatively planar, the metal centers being linked via pairs of μ₂-SR and μ₃-SR units. Complex [1]₂²⁺ oxygenates and sulfidizes with O₂ and S₈, respectively, to give [Cp*Ru(NiS₂N₂)(η²- E₂)]⁺ (E = O, S), which were characterized spectroscopically and crystallographically. Solutions of [1]₂ (OTf)₂ also react with CO and MeNC to give the corresponding adducts [Cp*Ru(NiS₂N₂)L]OTf, where L = CO and MeNC. The v_CO = 1901 cm^-1 for the CO adduct indicates the excellent donating power of the NiS₂N₂ ligand. The Cp*Ru⁺ derivative of the bulkier version of the NiS₂N₂ species, Ni(bme*-daco) (bme*-daco = [1,5-bis(2-mercapto-2-methylpropyl)-1,5-diazacyclooctane]), is the monomeric analogue of 1⁺, [Cp*Ru(NCMe)(Ni-(bme*-daco))]⁺, whose structure was confirmed spectroscopically and crystallographically. In this species the thiolato ligands are doubly bridging and the Cp*Ru subunit adopts the usual piano-stool geometry with a terminal MeCN ligand. The MeCN is readily displaced by CO and O₂ to give the corresponding adducts. The reaction of CpRu(PPh₃)₂Cl and NiS₂N₂ produced the PPh₃ adduct [CpRu(NiS₂N₂)(PPh₃)]Cl, wherein the PPh₃ ligand is nonlabile. The corresponding reaction of NiS₂N₂ with sources of (arene)RuCl⁺ gave the expected adducts [(arene)Ru(Cl)(NiS₂N₂)]⁺, isolated as their OTf^- salts.

Full text of DOI:10.1021/om020724e

Organometallics 2003, 22, 1619-1625
1619
Ru th en iu m Der iva tives of NiS2N2 Com p lexes a s
An a logu es of Bioor ga n om eta llic Rea ction Cen ter s
Michael A. Reynolds, Thomas B. Rauchfuss,* and Scott R. Wilson
Department of Chemistry, University of Illinois at Urbana-Champaign,
600 S. Mathews Avenue, Urbana, Illinois 61801
Received September 3, 2002
Recent results from structural biology demonstrate the catalytic significance of Ni(SR)2L2
centers attached to a second metal that binds CO, in particular the NiFe hydrogenases
and acetyl CoA synthase. In experiments aimed at developing bimetallic derivatives
exhibiting an affinity for CO, we have studied Ru(II) derivatives of nickel diaminodithiolates
and the reactivity of these complexes toward CO and other small molecules. The reaction of
[Cp*Ru(NCMe)3]OTf and NiS2N2 (S2N2 ) N,N′-bis(2-mercaptoethyl)-N,N′-dimethyl-1,3-
diaminoethane) gives [Cp*Ru(NiS2N2)]2(OTf)2 ([1]2(OTf)2), which exists as a monomer-dimer
equilibrium in MeCN solution. Crystallographic analysis of [1]2(OTf)2 reveals a centrosym-
metric dication with the Ru being quasi-octahedral and the NiS2N2 coordination sphere being
relatively planar, the metal centers being linked via pairs of µ2-SR and µ3-SR units. Complex
2+
[1]2 oxygenates and sulfidizes with O2 and S8, respectively, to give [Cp*Ru(NiS2N2)(η2-
E2)]+ (E ) O, S), which were characterized spectroscopically and crystallographically.
Solutions of [1]2(OTf)2 also react with CO and MeNC to give the corresponding adducts
[Cp*Ru(NiS2N2)L]OTf, where L ) CO and MeNC. The νCO ) 1901 cm-1 for the CO adduct
indicates the excellent donating power of the NiS2N2 ligand. The Cp*Ru+ derivative of the
bulkier version of the NiS2N2 species, Ni(bme*-daco) (bme*-daco ) [1,5-bis(2-mercapto-2-
methylpropyl)-1,5-diazacyclooctane]), is the monomeric analogue of 1+, [Cp*Ru(NCMe)(Ni-
(bme*-daco))]+, whose structure was confirmed spectroscopically and crystallographically.
In this species the thiolato ligands are doubly bridging and the Cp*Ru subunit adopts the
usual piano-stool geometry with a terminal MeCN ligand. The MeCN is readily displaced
by CO and O2 to give the corresponding adducts. The reaction of CpRu(PPh3)2Cl and NiS2N2
produced the PPh3 adduct [CpRu(NiS2N2)(PPh3)]Cl, wherein the PPh3 ligand is nonlabile.
The corresponding reaction of NiS2N2 with sources of (arene)RuCl+ gave the expected adducts
[(arene)Ru(Cl)(NiS2N2)]+, isolated as their OTf- salts.
Ch a r t 1. Active Site Str u ctu r es for Acetyl CoA
Syn th a se (ACS) a n d NiF e Hyd r ogen a se
In tr od u ction
Nature employs hydrogenase enzymes for the sensing
and conversions of dihydrogen. These enzymes can be
classified according to the metal content at their active
sites: Fe-only, NiFe, and metal free.1 The active sites
of all three enzyme classes exhibit remarkably novel
structures, especially in the organometallic context. A
mechanistic understanding of these enzymes would be
significant for both basic organometallic chemistry as
well as the commercial utilization of dihydrogen. In the
case of the Fe-only hydrogenases, low molecular weight
models have achieved at least a rudimentary level of
success with respect to structure2,3 and function.4
Despite the fact that high-resolution crystal struc-
tures of the enzyme have been available for several
years,5-7 little progress has been achieved in the
characterization of Ni-Fe complexes with suitable re-
activity. The active sites of the NiFe enzymes consist
of a dithiolate-linked Ni-Fe center that bears little
resemblance to known compounds (Chart 1). Further-
more, the exact site of H2 activation remains contro-
versial.8-11 One reason to expect H2 binding at Fe is the
wealth of precedent for ferrous H2 complexes.12-16
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2001, 219-221, 1055-1074.
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R. H. J . Am. Chem. Soc. 1998, 120, 548-555.
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Field, M. J . J . Am. Chem. Soc. 1999, 121, 4468-4477.
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10.1021/om020724e CCC: $25.00 © 2003 American Chemical Society
Publication on Web 03/14/2003

1620 Organometallics, Vol. 22, No. 8, 2003
Reynolds et al.
Ch a r t 2. Str u ctu r a l Mod els for th e Ni-F e Hyd r ogen a se Meta lloen zym e Active Sitea
a
See text for references.
Representative synthetic models for the NiFe-hydroge-
nase active site are shown in Chart 2. The primary focus
has been on the preparation of the Ni(µ-SR)2Fe centers,
which are observed in the enzyme structure. Commonly
such bimetallic complexes are prepared by the interac-
tion of iron reagents with diaminodithiolates of Ni(II).
These diaminodithiolate building blocks comprise a
fairly large class of complexes.17 The Ni(SR)2(NR3)2
coordination set simulates the Ni(SR)4 site seen crys-
tallographically in the enzymes.18-21 Two unresolved
deficiencies with the applicability of Ni(SR)2(NR3)2 as
a subunit in these models are (i) that the naturally
occurring nickel thiolate is distorted toward the tetra-
hedral geometry, whereas the nickel is typically planar
in its diaminodithiolates, and (ii) the naturally occurring
Ni(SR)4 site is probably anionic. The other half of the
bimetallic active site features an Fe(CN)2(CO) subunit,
as established by combined crystallographic and spec-
troscopic studies. Many examples of Fe-CN-CO species
have been examined recently,22-24 some even linked to
a nickel thiolate.25 Bimetallic derivatives of Ni(SR)2-
(NR3)2 complexes are also relevant to the recently
characterized active site of acetyl CoA synthase (ACS,
Chart 1), which features a diamido-dithiolato nickel
center linked to copper via two thiolato bridges. ACS is
responsible for forming acetyl groups, which may occur
via methyl transfer from nickel to a Cu-bound CO
ligand.26
Several years ago we started to explore the synthesis
of fac-L3Fe(II) complexes of the NiS2N2 in a search for
complexes that would exhibit some reactivity at one of
the two metals. Initial studies focused on (Me3TACN)-
Fe2+ derivatives (Me3TACN ) N,N′,N′′-trimethyltriaza-
cyclononane). We synthesized the species [(Me3TACN)-
27
FeCl(NiS2N2)]+ via the reaction of (Me3TACN)FeCl2
with standard Ni(SR)2(NR3)2 building blocks, but the
resulting bimetallic complex, which was high spin,
showed little affinity for π-acid ligands.28 In a revised
approach, we synthesized the low-spin complex [CpFe-
(CO)(NiS2N2)]+ via the reaction of [CpFe(CO)2(CH2-
CMe2)]BF4 again using the NiS2N2 building block. The
resulting salt {CpFe(CO)[NiS2N2]}BF4, also character-
ized crystallographically,29 was found to be substitution-
ally inert. The lack of suitable reactivity in these Ni-Fe
species led us to redirect our efforts toward Ru ana-
logues with the knowledge that Ru(II) typically exhibits
a high affinity for π-acid ligands and H2.30 In this paper
(11) Stein, M.; Lubitz, W. Curr. Opin. Chem. Biol. 2002, 6, 243-
249.
(12) Scharrer, E.; Chang, S.; Brookhart, M. Organometallics 1995,
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(13) Morris, R. H.; Sawyer, J . F.; Shiralian, M.; Zubkowski, J . J .
Am. Chem. Soc. 1985, 107, 5581-5582.
(14) Amrhein, P. I.; Drouin, S. D.; Forde, C. E.; Lough, A. J .; Morris,
R. H. J . Chem. Soc., Chem. Commun. 1996, 1665-1666.
(15) Landau, S. E.; Morris, R. H.; Lough, A. J . Inorg. Chem. 1999,
38, 6060-6068.
(16) Kubas, G. J . Metal Dihydrogen and σ-Bond Complexes; Kluwer
Academic/Plenum Publishers: New York, 2001.
(17) Kru¨ger, H.-J .; Peng, G.; Holm, R. H. Inorg. Chem. 1991, 30.
(18) Volbeda, A.; Charan, M.-H.; Piras, C.; Hatchikian, E. C.; Frey,
M.; Fontecilla-Camps, J . C. Nature 1995, 373, 580-587.
(19) Volbeda, A.; Garcin, E.; Piras, C.; de Lacey, A. L.; Fernandez,
V. M.; Hatchikian, E. C.; Frey, M.; Fontecilla-Camps, J . C. J . Am.
Chem. Soc. 1996, 118, 12989-12996.
(22) Lai, C.-H.; Reibenspies, J . H.; Darensbourg, M. Y. Angew.
Chem., Int. Ed. Engl. 1996, 35, 2390-2393.
(23) Rauchfuss, T. B.; Contakes, S. M.; Hsu, S. C. N.; Reynolds, M.
A.; Wilson, S. R. J . Am. Chem. Soc. 2001, 123, 6933-6934.
(24) Sellmann, D.; Geipel, F.; Heinemann, F. W. Chem. Eur. J . 2002,
8, 958-966.
(25) Sellmann, D.; Geipel, F.; Lauderbach, F.; Heinemann, F. W.
Angew. Chem., Int. Ed. 2002, 41, 632-634.
(26) Doukov, T. I.; Iverson, T. M.; Seravalli, J .; Ragsdale, S. W.;
Drennan, C. L. Science 2002, 298, 567-572.
(27) Moreland, A. C.; Rauchfuss, T. B. Inorg. Chem. 2000, 39, 3029-
(20) Garcin, E.; Vernede, X.; Hatchikian, E. C.; Volbeda, A.; Frey,
M.; Fontecilla-Camps, J . C. Structure 1999, 7, 557-566.
(21) Higuchi, Y.; Ogata, H.; Miki, K.; Yasuoka, N.; Yagi, T. Structure
1999, 7, 549-556.
3036.
(28) Moreland, A. C. Unpublished results, 2000.
(29) Eckermann, A. L., Ph.D. Thesis, University of Illinois at
Urbana-Champaign, 2003.

Ruthenium Derivatives of NiS2N2 Complexes
Organometallics, Vol. 22, No. 8, 2003 1621
Ch a r t 3. Str u ctu r es of NiS2N2 a n d Ni(bm e*-d a co)
Meta lloliga n d sa
a
See text for references.
we summarize these results, focusing especially on
(C5R5)Ru+ and (C6R6)Ru2+ derivatives of the NiS2N2
metalloligands. We demonstrate that the Ru center,
used as a surrogate for the naturally occurring Fe, is
reactive toward π-acid ligands.
F igu r e 1. Molecular structure of the dication in [Cp*Ru-
(NiS2N2)]2(OTf)2, [1]2(OTf)2, with thermal ellipsoids drawn
at the 50% probability level.
Ta ble 1. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for [1]2(OTf)2
Resu lts a n d Discu ssion
Ru(1)-S(1)
Ru(1)-S(2)
Ru(1)-S(1A)
Ni(1)-S(1)
Ni(1)-S(2)
Ni(1)-N(1)
Ni(1)-N(2)
2.4736(16) S(1)-Ru(1)-S(1A)
2.4672(17) S(2)-Ru(1)-S(1A)
2.4396(17) S(1)-Ni(1)-S(2)
2.1401(18) N(1)-Ni(1)-N(2)
2.1761(17) C(6)-S(1)-Ru(1)
73.81(7)
81.61(6)
88.15(7)
88.6(2)
122.1(2)
98.9(2)
The overall synthetic methodology followed in this
work entails treatment of various ruthenium electro-
philes with nickel complexes of either of two diamino
dithiolates, which are shown in Chart 3.
Syn th esis of [Cp *Ru (NiS2N2)]2(OTf)2 ([1]2(OTf)2).
Treatment of MeCN solutions of [Cp*Ru(MeCN)3]OTf
with NiS2N2 furnished dark brown [Cp*Ru(NiS2N2)]2-
(OTf)2 ([1]2(OTf)2) in excellent yield (eq 1).
1.938(5)
1.943(5)
C(6)-S(1)-Ni(1)
Ru(1)-S(1)-Ni(1)
83.41(5)
S(1)-Ru(1)-S(2) 74.84(5)
Ru(1A)-S(1)-Ni(1) 124.10(7)
2.4396(17) Å. The Ni environment of the NiS2N2 moiety
is similar to that observed in [Ni(NiS2N2)2]2+ 31
.
2 [Cp*Ru(NCMe)3]OTf + 2 NiS2N2 -6 MeCN8
Complex [1]2 proved to be unreactive toward Ph-
2+
CCH, cyclohexene, Et3SiH, H2O, protic acids, and H2
in both MeCN and MeNO2, although it does react with
O2, S8, CO, and CNMe as described below. Reactions of
[Cp*Ru(NiS2N2)]2(OTf)2 (1)
[1]2(OTf)2
2+
[1]2 with more aggressive reagents such as LiAlH4,
The salt [1]2(OTf)2 is moderately air-stable in the solid
state but rapidly oxygenates when exposed to air in
solution (see below). H NMR spectroscopic analysis of
NaBH4, and NaOMe led to decomposition into NiS2N2
and unidentified ruthenium-containing products. Reac-
tion of [Cp*RuCl]4 with 4 equiv of NiS2N2 in MeCN
1
produced the chloride salt of [1]22+, as indicated by H
[1]2(OTf)2 in CD3CN showed broadened signals that
were shifted downfield of those in the free NiS2N2. Upon
cooling the solution to -30 °C, two subspectra can be
resolved, which we attribute to [Cp*Ru(NiS2N2)(CD3-
1
NMR spectroscopy.
Rea ctivity of [1]2(OTf)2 w ith O2 a n d S8. Exposure
of an MeCN solution of [1]2(OTf)2 to air quantitatively
afforded the red-brown peroxo species [Cp*Ru(NiS2N2)-
(η2-O2)]OTf ([2]OTf) (eq 3).
2+
CN)]+ and [Cp*Ru(NiS2N2)]2 (eq 2).
[Cp*Ru(NiS2N2)]22+ + 2 MeCN h
[Cp*Ru(NiS2N2)]22+ + 2 O2 f
2+
[1]2
2+
2 [Cp*Ru(NiS2N2)(MeCN)]+ (2)
[1]2
2 [Cp*Ru(NiS2N2)(O2)]+ (3)
2+
The high-temperature 1H NMR spectrum is simple, due
to rapid monomer-dimer equilibria, with the equilib-
rium favoring the monomer [Cp*Ru(NiS2N2)(NCMe)]+
(Supporting Information). The ESI-MS spectrum of
[1]2(OTf)2 shows a parent ion with m/z ) 501 corre-
sponding to Cp*Ru(NiS2N2)+, i.e., one-half of the dimer
unit. Signals for [Cp*Ru(NiS2N2)(NCMe)]+ were not
observed.
ESI-MS analysis confirms the formula (m/z ) 533.1).
1
Aside from the methylene signals, the H NMR spec-
trum shows a singlet for the two NMe groups and a
2+
singlet for Cp* shifted 0.12 ppm upfield vs [1]2
.
Crystallographic analysis confirms the close similarity
2+
of the Ru-Ni bimetallic unit in 2+ and [1]2 (Figure 2,
Crystallographic analysis of [1]2(OTf)2 reveals a cen-
trosymmetric dication with the Ru centers being quasi-
octahedral and the NiS2N2 coordination sphere being
relatively planar (Figure 1, Table 1). The Ru and Ni
centers are linked via the two µ-SR units. All three
Ru-S distances fall in a narrow range of 2.4736(16)-
Table 2). In principle, the species [Cp*Ru(L)(NiS2N2)]
could exist as four possible isomers; however only one
isomer (Chart 4) was observed for 2+. In terms of the
2+
relative stereochemistry, the Cp* ligands in [1]2 are
axial, while the Cp* in 2+ is equatorial. Cations [Ni-
2+
(NiS2N2)]2
and Fe(NO)2[Ni(S2N2′)] (S2N2′ ) N,N′-
(30) Law, J . K.; Mellows, H.; Heinekey, D. M. J . Am. Chem. Soc.
2002, 124, 1024-1030.
(31) Turner, M. A.; Driessen, W. L.; Reedijk, J . Inorg. Chem. 1990,
29, 3331-3335.

1622 Organometallics, Vol. 22, No. 8, 2003
Reynolds et al.
Complex [1]2(OTf)2 also reacts with elemental sulfur
at room temperature in MeCN solution to give the
brown persulfide [Cp*Ru(NiS2N2)](η2-S2)]OTf, [3]OTf
(eq 4).
[Cp*Ru(NiS2N2)]22+ + 0.5 S8 f
2+
[1]2
2 [Cp*Ru(NiS2N2)(S2)]+ (4)
3+
The 1H NMR data for 3+ resemble that for the dioxygen
complex 2+. Further supporting the structure proposed
for 3+, the FAB-MS showed a parent ion for [Cp*Ru-
(NiS2N2)(S2)]+ (m/z ) 565) and the fragment [Cp*Ru-
(NiS2N2)]+ (m/z ) 501).
Rea ction s of [1]2(OTf)2 w ith CO a n d MeNC.
Acetonitrile solutions of [1]2(OTf)2 react with CO and
MeNC to give the corresponding adducts [Cp*Ru-
(NiS2N2)L]OTf, [4]OTf for L ) CO and [5]OTf for L )
MeNC (eq 5).
F igu r e 2. Molecular structure of the cation of [Cp*Ru-
(NiN2S2)(η2-O2)](OTf), [2](OTf), with thermal ellipsoids
drawn at the 30% probability level.
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for [2]OTf
[Cp*Ru(NiS2N2)]22+ + 2 L f
Ru(1)-O(1)
Ru(1)-O(2)
Ru(1)-S(1)
Ru(1)-S(2)
O(1)-O(2)
Ni(1)-S(1)
Ni(1)-S(2)
Ni(1)-N(1)
Ni(1)-N(2)
2.054(6)
2.041(6)
2.418(2)
O(2)-Ru(1)-S(1)
S(1)-Ni(1)-S(2)
N(1)-Ni(1)-N(2)
86.1(3)
87.74(8)
89.3(2)
90.45(16)
90.75(17)
111.8(3)
96.8(3)
2+
[1]2
2 [Cp*Ru(NiS2N2)(L)]+ (5)
4+(L ) CO)
2.4086(19) N(1)-Ni(1)-S(1)
1.371(8)
2.144(2)
2.130(2)
1.939(5)
1.925(5)
N(2)-Ni(1)-S(2)
C(1)-S(1)-Ru(1)
C(1)-S(1)-Ni(1)
Ru(1)-S(1)-Ni(1) 82.84(7)
C(6)-S(2)-Ru(1) 114.0(3)
Ni(1)-S(2)-Ru(1) 83.36(6)
C(6)-S(2)-Ni(1) 98.5(3)
5+(L ) CNMe)
The IR spectrum of 4+ exhibits νCO at 1901 cm-1, the
low value of which is indicative of the excellent electron-
donating power of the NiS2N2 ligand. For comparison,
νCO for the structurally related phosphine complexes
[Cp*Ru(PMe3)2(CO)]+ and [Cp*Ru(dppe)(CO)]+ occur at
O(1)-Ru(1)-O(2) 39.1(2)
S(1)-Ru(1)-S(2) 75.71(7)
O(1)-Ru(1)-S(2) 95.6(3)
Ch a r t 4. P ossible Isom er s of [Cp *Ru (L)(NiS2N2)]+a
1935 and 1975 cm-1 35,36
respectively. FAB-MS shows
,
peaks for [Cp*Ru(NiS2N2)(CO)]+ as well as [Cp*Ru-
(NiS2N2)]+. The MeNC adduct [5]OTf proved to be
spectroscopically similar to 4+, the νCN again occurring
at relatively low energy at 2070 cm-1. Addition of excess
2+
of MeNC with [1]2
gave the bis(adduct) [Cp*Ru-
(NiS2N2)(CNMe)2]+, which was characterized spectro-
scopically. Telling 1H NMR data are the presence of
diastereotopic CNMe signals as well as signals consis-
tent with an unsymmetrically bound NiS2N2.
[Cp *Ru (Ni(bm e*-d a co))(MeCN)]OTf ([6]OTf). In
this series of experiments we examined a bulkier version
of the NiS2N2 species Ni(bme*-daco), where bme*-daco
) [1,5-bis(2-mercapto-2-methylpropyl)-1,5-diazacyclooc-
tane] (Chart 3). The goal was to generate a stable
monomeric analogue of [1]22+. Solutions of [Cp*Ru-
(NCMe)3]+ and Ni(bme*-daco) react readily in MeCN
solution to produce dark brown [Cp*Ru(NCMe)(Ni-
(bme*-daco))]+ (6+) (eq 6). FAB-MS analysis shows a
a
The one in the upper left is observed.
diethyl-3,7-diazanonane-1,9-dithiolate) adopt similar
conformations.31,32 The NiS2N2 ligand adopts a bowl-
like cavity under the η2-O2 ligand. In comparison to
[1]22+, the Ru(1)-S(1) and Ru(1)-S(2) distances of 2+
are 0.056-0.059 Å shorter. The O-O distance of 1.371-
(8) Å is similar to those observed in [Cp*Ru(dppe)(η2-
O2)]+ (1.398(5) Å)33,34 and [Cp*Ru(dppm)(η2-O2)]+ (1.37-
(1) Å),34 although the Ru-O distances are slightly
longer. The O2 ligand was not displaced by CO and was
also unreactive toward H2 in refluxing MeCN solution.
(32) Osterloh, F.; Saak, W.; Pohl, S. Chem. Commun. 1997, 979-
978.
(33) Kirchner, K.; Mauthner, K.; Mereiter, K.; Schmid, R. J . Chem.
Soc., Chem. Commun. 1993, 892-894.
(34) J ia, G.; Ng, W. S.; Chu, H. S.; Wong, W.-T.; Yu, N.-T.; Williams,
I. D. Organometallics 1999, 18, 3597-3602.

Ruthenium Derivatives of NiS2N2 Complexes
Organometallics, Vol. 22, No. 8, 2003 1623
duct [CpRu(NiS2N2)(PPh3)]Cl ([9]Cl), isolated as brick
red crystals (eq 7).
CpRu(PPh3)2Cl + NiS2N2 f
[CpRu(NiS2N2)(PPh3)]Cl + PPh3 (7)
[9]Cl
Analysis by 1H NMR spectroscopy and ESI-MS con-
firmed the formula. The PPh3 ligand in 9+ is not labile:
complex 9+ showed no reaction toward CO or NaBH4.
No reaction occurred between NiS2N2 and CpRu-
(PPh3)2H, indicating that the phosphine ligands in the
hydrido complex are nonlabile (presumably due to the
absence of π-donor ligands). We then examined the
reaction of NiS2N2 with CpRu(PPh3)2SH, which is
known to readily undergo CO-for-PPh3 ligand ex-
change,37 but this reaction instead afforded Cp4Ru4S4,
resulting from the thermally induced condensation of
CpRu(PPh3)2SH.38
F igu r e 3. Molecular structure of the cation of [Cp*Ru-
(Ni(bme*-daco))(NCMe)]OTf, [6]OTf, with thermal ellip-
soids drawn at the 50% probability level.
[(a r en e)Ru (Cl)(NiS2N2)]P F 6. Treatment of NiS2N2
with sources of (arene)RuCl+ (arene ) C6Me6, cymene)
gave the expected adducts [(arene)RuCl(NiS2N2)]+, iso-
lated as their OTf- salts (eq 8).
Ta ble 3. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for [6]OTf
Ru(1)-S(1)
Ru(1)-S(2)
Ru(1)-N(3)
Ni(1)-S(1)
Ni(1)-S(2)
Ni(1)-N(1)
Ni(1)-N(2)
S(1)-Ru(1)-S(2) 73.21(6)
S(1)-Ru(1)-N(3) 99.04(11)
N(3)-Ru(1)-S(2) 96.84(11)
2.4346(18) N(3)-C(25)-C(26) 177.4(5)
2.4628(18) C(25)-N(3)-Ru(1) 172.2(3)
[(arene)RuCl2]2 + 2 NiS2N2 2 AgOTf8
2.051(4)
S(1)-Ni(1)-S(2)
85.39(8)
[(arene)RuCl(NiS2N2)]OTf (8)
[10]OTf (arene ) cymene)
[11]OTf (arene ) C6Me6)
2.1519(17) N(1)-Ni(1)-N(2)
2.1548(17) C(1)-S(1)-Ru(1)
92.79(16)
123.80(15)
97.03(15)
1.983(3)
1.977(4)
C(1)-S(1)-Ni(1)
Ni(1)-S(1)-Ru(1) 93.75(8)
C(10)-S(2)-Ru(1) 125.37(14)
C(10)-S(2)-Ni(1) 97.22(15)
Ni(1)-S(2)-Ru(1) 92.89(7)
These cationic complexes proved thermally and chemi-
cally robust, and spectroscopic evidence supports the
expected symmetric structures.
parent ion at m/z ) 585.1 for [Cp*Ru(Ni(bme*-daco))]+.
1
The H NMR spectrum of 6+, while complex, exhibits
Su m m a r y
signals that can be reasonably assigned to those ex-
pected for the bme*-daco ligand at δ 4.5-1.8. The
geminal methyl groups appear as singlets at δ 1.57 and
1.13 and the Cp* methyl resonance is observed as a
sharp singlet at δ 1.56. The coordinated MeCN rapidly
exchanges in CD3CN solution.
This project explored the preparative accessibility of
thiolato-bridged Ni-Ru derivatives, as a starting point
for the further development of functional models for bio-
organometallic reaction centers. In particular the NiFe-
hydrogenases and acetyl CoA synthase (ACS) both
feature four-coordinate Ni centers bound to a second
metal that is proposed to bind π-acids as either sub-
strates (ACS) or constituative ligands. Although many
derivatives of Ni(SR)2(amine)2 are known, the resulting
bimetallic complexes studied to date are unreactive with
respect to the binding of π-acid ligands.
Crystallographic analysis demonstrates that 6+, un-
like [1]22+, consists of isolated Ru-Ni species wherein
the thiolato ligands are only doubly bridging (Figure 3,
Table 3). The Cp*Ru moiety adopts the usual piano-stool
2+
geometry as seen in [1]2 and 2+. The Ru centers
feature an MeCN ligand with a Ru-N-C angle of 172.2-
(3)° and Ru(1)-N(3) distance of 2.051(4) Å. The Ni
center sits in the pocket of the bme*-daco ligand in a
square planar arrangement, as observed for the NiS2N2
On the basis of the present results, the NiS2N2 species
could be expected to serve more generally as a support-
ing ligand in organometallic chemistry, e.g., in place of
diphosphines. In terms of their affinity for (cyclopenta-
dienyl)ruthenium(II) centers, the NiS2N2 species serve
as innocent spectator ligands, although one that is more
basic than typical Ph2P-derived chelating diphos-
phines.22 The high basicity of the NiS2N2 is further
indicated by the tendency of [Cp*Ru(NiS2N2)]+ to dimer-
ize via formation of µ3-thiolato ligands.
ligands in the structures of [1]2 and 2+.
2+
Complex 6+ reacts rapidly with air in solution to give
the peroxo complex [Cp*Ru(Ni(bme*-daco))(η2-O2)]OTf
([7]OTf), which proved structurally similar to 2+ (Sup-
porting Information). Carbonylation of solutions of 6+
gave the adduct [Cp*Ru(Ni(bme*-daco))(CO)]OTf, [8]-
OTf (νCO ) 1914 cm-1).
[Cp Ru (P P h 3)(NiS2N2)]Cl. The phosphine ligands in
CpRu(PPh3)2Cl are known to be labile,37 and this
encouraged us to examine the reaction of (NiS2N2) and
CpRu(PPh3)2Cl, a reaction that afforded the PPh3 ad-
The reactivity of [Cp*Ru(NiS2N2)]+ toward dioxygen
differs from the corresponding oxygenations of NiS2N2
and Ni(bme*-daco), which afford sulfinato (RSO2-) and
sulfenato (RSO-) complexes.39-42 It is well known that
(35) Tilley, T. D.; Grubbs, R. H.; Bercaw, J . E. Organometallics 1984,
3, 274.
(36) Xia, H. P.; Wu, W. F.; Ng, W. S.; Williams, I. D.; J ia, G.
Organometallics 1997, 16, 2940-2947.
(37) Amarasekera, J .; Rauchfuss, T. B. Inorg. Chem. 1989, 28, 3875.
(38) Amarasekera, J .; Rauchfuss, T. B.; Wilson, S. R. J . Chem. Soc.,
Chem. Commun. 1989, 14, 14.
(39) Farmer, P. J .; Solouki, T.; Mills, D. K.; Soma, T.; Russell, D.
H.; Reibenspies, J . H.; Darensbourg, M. Y. J . Am. Chem. Soc. 1992,
114, 4601-4605.

1624 Organometallics, Vol. 22, No. 8, 2003
Reynolds et al.
Ta ble 4. Deta ils of Da ta Collection a n d Str u ctu r e Refin em en t for [1]2(OTf)2, [2]OTf, a n d [6]OTf
[1]2(OTf)2
[2]OTf
[6]OTf
chemical formula
temp (K)
cryst size (mm)
space group
a (Å)
C
19H33F3N2NiO3RuS3
C19H33F3N2NiO5RuS3
193(2)
C27H46F3N3NiO3RuS3
193(2)
193(2)
0.66 × 0.06 × 0.04
0.47 × 0.20 × 0.08
0.30 × 0.10 × 0.07
P1h
P21/c
P21/c
9.252(2)
12.950(5)
15.019(5)
27.320(9)
90
91.271(7)
90
5312(3)
8
1.707
0.71073
11.084(10)
18.259(16)
16.519(15)
90
92.401(8)
90
3340(5)
4
1.252
0.71073
b (Å)
c (Å)
11.413(3)
13.835(3)
101.343(4)
99.102(4)
101.017(4)
1376.5(6)
2
R (deg)
â (deg)
γ (deg)
V (Å3)
Z
Dcalcd (Mg m-3
)
1.569
0.71073
µ (Mo KR, mm-1
)
max./min. transmn
no. of reflns measd/indep
no. of data/restraints/params
GOF
0.9950/0.8532
8562/5035
5035/0/323
0.896
0.7744/0.6440
39985/12786
12786/1047/835
0.968
0.9890/0.8661
21653/7944
7944/0/380
0.939
Rint
0.0665
0.0671
0.0623
R1[I >2σ] (all data)a
wR2 [I >2σ] (all data)b
max. peak/hole (e-/Å3)
0.0491 (0.1047)
0.1032 (0.1197)
1.019/-0.691
0.0588 (0.1513)
0.1547 (0.1919)
1.340/-0.609
0.0456 (0.0964)
0.0943 (0.1079)
1.727/-1.202
R1 ) ∑||Fo| - |Fc||/∑|Fo|. wR2 ) {∑[w(Fo - Fc2)2]/∑[w(Fo2)2]}1/2
.
a
b
2
η2-O2 ligands are nucleophilic,43,44 so it is not surprising
that oxygen atom transfer from the peroxy ligand to the
thiolate is not observed.
brown crystals precipitated from solution and were collected
and washed with Et2O. Yield: 260 mg (81%). H NMR (CD3-
1
CN, 20.1 °C): δ 3.72 (br, m, 2H), 3.12 (br, m, 2H), 2.61 (m,
4H), 2.51 (s, 6H), 3.38 (br, m, 2H), 2.15 (m, 2H), 1.56 (br, s,
15H). 1H NMR (CD3CN, 60.1 °C): δ 3.72 (m, 2H), 3.13 (m, 2H),
2.65-2.57 (m, 4H), 2.51 (s, 6H), 2.39 (m, 2H), 2.18 (m, 2H),
1.61 (s, 15H). FAB-MS (MeCN): m/z 501 [Cp*Ru(NiS2N2)]+.
Anal. Calcd for C19H33F3N2NiO3RuS3: C, 35.09; H, 5.11; N,
4.31. Found: C, 35.13; H, 5.22; N, 4.37.
[Cp *Ru (NiS2N2)(η2-O2)]OTf ([2]OTf). A solution of 100 mg
(0.077 mmol) of [1]2(OTf)2 in 10 mL of MeCN was stirred in
air for 1.5-2.0 h, resulting in a color change from dark brown
to red-brown. The solvent volume was reduced under vacuum
to ca. 2 mL and then layered with 15 mL of Et2O, which was
cooled to -20 °C for 8 h to produce red-brown crystals. Yield:
94 mg (95%). 1H NMR (CD3CN): δ 4.25 (m, 2H), 3.40 (m, 2H),
2.72 (m, 4H), 2.59 (s, 6H), 2.57 (m, 4H), 1.49 (s, 15H, Cp*).
ESI-MS (MeCN): m/z 533 [Cp*Ru(NiS2N2)(η2-O2)]+. Anal.
Calcd for C19H33F3N2NiO5RuS3: C, 33.44; H, 4.87; N, 4.10.
Found: C, 33.80; H, 5.08; N, 4.29.
[Cp *Ru (NiS2N2)(η2-S2)]OTf ([3]OTf). A solution of 142 mg
(0.109 mmol) of [1]2(OTf)2 and 10.0 mg (0.312 mmol) of S8 was
prepared in 15 mL of MeCN. After 2 h, the solvent volume
was reduced to ca. 2 mL, and the concentrate was treated with
10 mL of Et2O to give a brown precipitate of crude [3]OTf.
Yield: 104 mg (74%). Dark brown single crystals were grown
by diffusion of Et2O into an MeCN solution of [3]OTf. 1H NMR
(CD3CN): δ 4.09 (m, 2H), 3.30 (m, 2H), 2.62-2.49 (m, 6H),
2.52 (s, 6H), 2.39 (m, 2H), 1.41 (s, 15H). FAB-MS (MeCN): m/z
565 [Cp*Ru(NiS2N2)(S2)]+; 501 [Cp*Ru(NiS2N2)]+. Anal. Calcd
for C19H33F3N2NiO3RuS5: C, 31.94; H, 4.65; N, 3.92. Found:
C, 32.03; H, 4.62; N, 4.11.
[Cp *Ru (NiS2N2)(CO)]OTf ([4]OTf). A 15 mL solution
containing 104 mg (0.080 mmol) of [1]2(OTf)2 was purged with
CO for 30 min, resulting in a color change from dark brown to
deep red. The solvent volume was reduced to ca. 1 mL, and
the concentrate was layered with 20 mL of Et2O, which after
8 h produced red-brown crystals of [4]OTf at -20 °C. Yield:
80 mg (75%). 1H NMR (CD3CN): δ 4.00 (m, 2H), 3.43 (m, 2H),
2.80 (m, 4H), 2.62 (s, 6H), 2.58 (m, 2H), 2.18 (m, 2H), 1.75 (s,
15H). IR (MeCN): νCO 1901 cm-1. FAB-MS (MeCN): m/z 529
[Cp*Ru(NiS2N2)(CO)]+; 501 [Cp*Ru(NiS2N2)]+. Anal. Calcd for
Exp er im en ta l Section
Gen er a l Con sid er a tion s. All air-sensitive manipulations
employed standard Schlenk line and drybox techniques.
Solvents were dried using a solvent purification system similar
to that described by Grubbs et al.45 Published procedures were
2-
followed in the preparation of NiS2N2 (S2N2 ) SCH2CH2-
NMeCH2CH2NMeCH2CH2S),31 Ni(bme*-daco),46 [Cp*Ru(NC-
Me)3]OTf,47 CpRu(PPh3)2Cl,48 and [(arene)RuCl2]2 (arene )
cymene or C6Me6).49 Elemental analyses were conducted by
the Microanalytical Laboratory in the School of Chemical
Sciences. 1H NMR spectra were acquired on a Unity Varian
400 or a Unity Varian 500 NMR spectrometer. Infrared spectra
were acquired on a Mattson Infinity Gold FT-IR spectrometer
using solution cells with CaF2 plates. Fast atom bombardment
(FAB) and electrospray ionization-mass spectrometry (ESI-MS)
were acquired using a Micromass 70 VSE double-focusing
sector instrument and a Micromass Quattro QHQ quadrapole-
hexapole-quadrapole instrument, respectively.
[Cp *Ru (NiS2N2)]2(OTf)2 ([1]2(OTf)2). A solution of 252 mg
(0.495 mmol) of [Cp*Ru(NCMe)3]OTf in 10 mL of MeCN was
added to a solution of 134 mg (0.506 mmol) of NiS2N2 in 15
mL of MeCN. After 1 h, the resulting dark brown solution was
reduced in volume to ca. 5 mL. The concentrate was layered
with 15 mL of Et2O and stored at -20 °C overnight. Dark
(40) Farmer, P. J .; Solouki, T.; Soma, T.; Russell, D. H.; Darens-
bourg, M. Y. Inorg. Chem. 1993, 32, 4171-4172.
(41) Farmer, P. J .; Verpeaux, J .-N.; Amatore, C.; Darensbourg, M.
Y.; Musie, G. J . Am. Chem. Soc. 1994, 116, 9355-9356.
(42) Font, I.; Buonomo, R.; Reibenspies, J . H.; Darensbourg, M. Y.
Inorg. Chem. 1993, 32, 5897-5898.
(43) Gubelmann, M. H.; Williams, A. F. Struct. Bonding 1983, 55,
1-65.
(44) Beaulieu, W. B.; Mercer, G. D.; Roundhill, D. M. J . Am. Chem.
Soc. 1978, 100, 1147-1152.
(45) Pangborn, A. B.; Giardello, M. A.; Grubbs, R. H.; Rosen, R. K.;
Timmers, F. J . Organometallics 1996, 15, 1518-1520.
(46) Darensbourg, M. Y.; Font, I.; Pala, M.; Reibenspies, J . H. J .
Coord. Chem. 1994, 32, 39-49.
(47) Fagan, P. J .; Ward, M. J .; Calabrese, J . C. J . Am. Chem. Soc.
1989, 111, 1698-1719.
C
20H33F3N2NiO4RuS3: C, 35.41, H, 4.90, N, 4.13. Found: C,
(48) Bruce, M. I.; Windsor, N. J . Aust. J . Chem. 1977, 30, 1601-
35.66, H, 5.03, N, 4.27.
[Cp *R u (NiS2N2)(CNMe)]OTf ([5]OTf). To a solution of
86.0 mg (0.066 mmol) of [1]2(OTf)2 in 10 mL of MeCN was
1604.
(49) Bennett, M. A.; Huang, T.-N.; Matheson, T. W.; Smith, A. K.
Inorg. Synth. 1982, 21, 74-78.

Ruthenium Derivatives of NiS2N2 Complexes
Organometallics, Vol. 22, No. 8, 2003 1625
1
added 0.20 mL (0.18 mmol) of a 0.91 M stock solution of CNMe
in MeCN. The solution initially became red for 2 min and then
turned red-brown. After stirring for 2 h, the solvent volume
was reduced to ca. 1 mL, and the solution was then layered
with 10 mL of Et2O to produce brown crystals. Yield: 55 mg
(60%). 1H NMR (CD3CN): δ 4.00 (2H, m), 3.87 (3H, s), 3.27
(2H, m), 2.64 (4H, m), 2.54 (6H, s), 2.44 (2H, m), 1.87 (2H, m),
1.67 (15H, s). IR (KBr): νCN 2070 cm-1. FAB-MS (MeCN): m/z
542.0 [Cp*Ru(NiS2N2)(CNMe)]+, 501.0 [Cp*Ru(NiS2N2)]+. Anal.
Calcd for C21H36F3N3NiO3RuS3: C, 36.48; H, 5.25; N, 6.08.
Found: C, 37.02; H, 5.54; N, 6.14.
room temperature. Yield: 70 mg (69%). H NMR (CD3CN): δ
7.43-7.26 (15H, m, Ph), 4.51 (5H, s, C5H5), 4.04 (2H, m), 3.89
(2H, m), 3.62 (2H, m), 3.42 (2H, m), 3.28 (2H, m), 2.83 (6H, s,
2 Me), 2.69 (2H, m). 31P NMR: δ 52.6. FAB-MS (MeCN): m/z
693.0 [CpRu(NiS2N2)(PPh3)]+, 430.9 [CpRu(NiS2N2)]+. Anal.
Calcd for C31H38ClN2NiRuPS3: C, 51.08; H, 5.25; N, 3.84.
Found: C, 49.99; H, 5.55; N, 3.88.
[(cym en e)Ru Cl(NiS2N2)]OTf ([10]OTf). A 5 mL MeCN
solution of 29.0 mg (0.11 mmol) of AgOTf was added dropwise
to a solution of 34 mg (0.06 mmol) of [(cymene)RuCl2]2 in 5
mL of MeCN. The solution became light yellow with a white
precipitate and was stirred for another 20 min, then allowed
to settle. The yellow solution was filtered and transferred to
a 10 mL solution of 30 mg (0.11 mmol) of NiS2N2 in MeCN.
The brown solution became cherry-red immediately upon the
addition. After 2 h, the solution was reduced in volume to ca.
1 mL, layered with 10 mL of Et2O, and stored at -20 °C
overnight to afford a red powder. Yield: 57 mg (80%). 1H NMR
(CDCl3): δ 5.45 (2H, d, J ) 6.0 Hz), 5.31 (2H, d, J ) 6.0 Hz),
4.70 (2H, m), 3.84 (2H, m), 3.61-3.44 (6H, m), 3.06 (6H, s, 2
N-Me), 2.94 (2H, m), 2.81 (1H, septet, J ) 6.8 Hz), 2.15 (3H,
s, Me), 1.20 (6H, d, J ) 6.8 Hz, 2 Me). FAB-MS (MeCN): m/z
535.0 [(C10H14)Ru(NiS2N2)Cl]+. Anal. Calcd for C19H32ClF3N2-
NiO3RuS3: C, 33.32; H, 4.71; N, 4.09. Found: C, 33.44; H, 5.08;
N, 4.19.
[Cp *Ru (NiS2N2)(CNMe)2]OTf. To a solution of 100 mg
(0.077 mmol) of [1]2(OTf)2 in 10 mL of MeCN was added 1.00
mL (0.46 mmol) of a 0.46 M solution of CNMe in MeCN. The
solution was stirred for 6 h and during this time became red.
The volume was then reduced and 15 mL of Et2O was added.
A red crystalline solid was produced after 1 day at -20 °C,
collected by filtration, and dried in vacuo. Yield: 99.0 mg
1
(88%). H NMR (CD3CN): 3.74 (s, 3H, Me), 3.45 (s, 3H, Me),
3.21(m, 2H), 3.04 (m, 1H), 2.98 (m, 1H), 2.96 (s, 3H, Me), 2.82
(s, 3H, Me), 2.64 (m, 1H), 2.58 (m, 1H), 2.49-2.36 (m, 4H),
2.19 (m, 1H), 2.09 (m, 1H), 1.73 (s, 15H, Cp*). IR (MeCN): νCN
2159; 2125 cm-1. FAB-MS (MeCN): m/z 583.1 [Cp*Ru(NiS2N2)-
(CNMe)2]+; 501.1 [Cp*Ru(NiS2N2)]+.
[Cp*Ru (Ni(bm e*-daco))(NCMe)]OTf ([6]OTf). In a glove-
box, a solution of 27.0 mg (0.053 mmol) of [Cp*Ru(NCMe)3]-
OTf in 2 mL of MeCN was added to a solution of 19.0 mg (0.055
mmol) of Ni(bme*-daco) in 3 mL of MeCN. The dark solution
was stirred for 2 h followed by reduction of the solvent volume
to ca.1 mL. Layering with 6 mL of Et2O afforded red-brown
[(C6Me6)Ru (NiS2N2)Cl]OTf ([11]OTf). Complex [11]OTf
was prepared in a manner similar to [10]OTf by reacting 100
mg (0.15 mmol) of [(C6Me6)RuCl2]2 in 5 mL of MeCN and 77
mg (0.30 mmol) of AgOTf in 5 mL of MeCN. The resulting
slurry was filtered into a solution of 79.0 mg (0.30 mmol) of
NiS2N2 in 10 mL of MeCN. After 2 h, the solvent was reduced
in vacuo to ca. 1 mL and layered with Et2O. After 1 day, a red
1
crystals of [6]OTf. Yield: 40 mg (98%). H NMR (CD3CN): δ
4.53 (m, 1H), 3.59 (dt, 2H), 2.92 (m, 2H), 2.61 (dt, 2H), 2.54-
2.44 (m, 6H), 1.83 (m, 3H), 1.57 (s, 6H, 2 Me), 1.56 (s, 15H,
C5Me5), 1.13 (s, 6H, 2 Me). FAB-MS (CH3CN): m/z 585.1
[Cp*RuNi(bme*-daco)]+. Anal. Calcd for C27H46F3N3NiO3-
RuS3: C, 41.92; H, 5.99; N, 5.43. Found: C, 41.35; H, 5.90; N,
5.28.
1
powder precipitated. Yield: 58 mg (70%). H NMR (CD3CN):
δ 4.40 (m, 2H), 3.23 (m, 2H), 2.73 (m, 2H), 2.57 (s, 6H), 2.53
(m, 2H), 2.42-2.30 (m, 4H), 1.98 (s, 18H, C6Me6). FAB-MS
(MeCN): m/z 563.0 [(C6Me6)Ru(NiS2N2)Cl]+. Anal. Calcd for
C
21H36ClF3N2NiO3RuS3: C, 35.38; H, 5.09; N, 3.93. Found: C,
[Cp *Ru (Ni(bm e*-d a co))(η2-O2)]OTf ([7]OTf). A 5 mL
solution of 20 mg (0.029 mmol) of [6]OTf in MeCN was stirred
in air for 30 min. The solvent was then removed under
vacuum, producing a red-brown solid, which was recrystallized
from a 10:1 mL mixture of MeCN/Et2O at -20 °C overnight.
35.30; H, 5.17; N, 4.18.
Cr ysta llogr a p h y. Crystals were mounted on thin glass
fibers using oil (Paratone-N, Exxon). Data were collected at
193(2) K on a Siemens CCD diffractometer. Crystal and
refinement details are given in Table 4. All structures were
solved using SHELXTL and direct methods; correct atomic
positions were deduced from an E map or by an unweighted
difference Fourier synthesis. H atom U’s were assigned as 1.2
times the Ueq’s of adjacent C atoms. Non-H atoms were refined
with anisotropic thermal coefficients. Successful convergence
of the full-matrix least-squares refinement of F2 was indicated
by the maximum shift/error for the last cycle.
1
Yield: 18 mg (80%). H NMR (CD3CN): δ 3.82 (m, 1H), 3.54
(m, 2H), 3.18 (m, 2H), 2.78 (m, 4H), 2.66-2.42 (m, 6H), 1.88,
(m, 1H), 1.73 (s, 6H, 2 Me), 1.43 (s, 15 H, Cp*), 1.37 (s, 6H, 2
Me). An analytically pure sample of this compound was not
obtained.
[Cp*Ru (Ni(bm e*-daco))(CO)]OTf ([8]OTf). A 5 mm NMR
tube charged with a 1 mL of CD3CN solution containing 10.0
mg (0.013 mmol) of [6]OTf was purged with CO for 1 h, during
1
which time the dark solution became red. H NMR (CD3CN):
Ack n ow led gm en t. This research was supported by
NIH.
δ 4.44 (m, 1H), 3.60 (m, 2H), 2.94 (m, 2H), 2.68-2.51 (m, 8H),
2.06-1.85 (m, 3H), 1.75 (s, 15H, Cp*), 1.65 (s, 6H, 2 Me), 1.13
(s, 6H, 2 Me). IR (CD3CN): νCO ) 1914 cm-1. Anal. Calcd for
C26H43F3N2NiO4RuS3: C, 40.95; H, 5.95; N, 3.67. Found: C,
40.18; H, 5.64; N, 3.98.
[Cp Ru (NiS2N2)(P P h 3)]Cl ([9]Cl). A solution of 100 mg
(0.138 mmol) of CpRu(PPh3)2Cl and 37.0 mg (0.140 mmol) of
NiS2N2 in 15 mL of MeCN was heated at reflux for 12 h. After
removal of the solvent, the red residue was washed with 30
mL of Et2O. Brick red crystals were grown after 48 h by slow
diffusion of Et2O into a solution of [9]Cl in 4 mL of MeCN at
Su p p or tin g In for m a tion Ava ila ble: Atomic coordinates,
bond lengths and angles, anisotropic displacement parameters,
and hydrogen coordinates for [1]2(OTf), [2]OTf, [6]OTf, and
[7]OTf. Variable-temperature 1H NMR spectrum of [1]22+. A
molecular structure of [7]OTf is included with thermal el-
lipsoids drawn at the 30% probability level. This material is
available free of charge via the Internet at http://pubs.acs.org.
OM020724E