Synthesis and X-ray structures of hydridotris(-pyrazolyl)borate carbonyl complexes of ruthenium

Abstract

A series of new hydridotris(1-pyrazolyl)borate (Tp) carbonyl complexes of ruthenium were synthesized. Treatment of [TpRu(CO)2X] (X = Br, I) with Me3NO in MeCN afforded [TpRu(CO)(NCMe)X] (X = Br (1), I (2)). The reactions of 1 and 2 with either neutral isocyanides or anionic dialkyldithiocarbamates to produce [TpRu(CO)(CNR)X] (X = Br, R = PhCH2 (3); X = Br, R =t_{Bu (4); X = I, R = PhCH}

2(5) X = I, R =tBu (6)) and [TpRu(CO)(h2-S2CNR2)] (R = Me (7), Et (8)), respectively. Compounds 1 and 2 reacts with RSH – Et3N in THF or 1,2-dimethoxyethane at reflux to give mono- and dithiolato diruthenium products, (cis)-[Tp2Ru2(CO)2(m-X)(m-SR)] (X=I, R=iPr (11); X = Br, R =tBu (13); X = I, R =tBu (14)), (trans, anti-1)-[Tp2Ru2(CO)2(m-SiPr)2] (9), (cis, syn)-[Tp2Ru2(CO)2(m-SiPr)2] (10), (trans, anti-1)-[Tp2Ru2(CO)2(m-StBu)2] (12), and (cis, anti-2)-[Tp2Ru2(CO)2(m-SiPr)(m-StBu)] (15). Compound 11 reacts with Me3NO to form stereo- and chemospecifically the first diruthenium sulfenate, (cis)-[Tp2Ru2(CO)2(m-I)(m-S(O)iPr)] (16) with the SO bond at the endo position with respect to carbonyls. Structures

8, 9, 10, 12, 14, 15, and 16 are described. © 2002 Elsevier Science B.V. All rights reserved.

Keywords:Ruthenium; Hydridotris(1-pyrazolyl)borate; Thiolates; Isocyanides; Dialkyl dithiocarbamates; Carbonyl

1. Introduction

Since the discovery of the pyrazolylborate ligands by Trofimenko in 1966 [1], an extensive transition-metal chemistry that utilizes these ligands has emerged [2]. Due to the apparent similarity in coordination and electronic structure to the cyclopentadienyl (Cp) ligand, much chemistry developed with the hydridotris(L -pyra-zolyl)borate (Tp) ligand has involved compounds whose Cp analogues were well established. Despite these similarities, there were for many years few and scattered reports of mixed-ligand complexes of ruthe-nium containing a Tp ligand, a carbonyl ligand, and other ligands [3], in contrast with numerous corre-sponding CpRu(CO) complexes [4]. The obvious reason is the lack of TpRu(CO) starting compounds. Previous attempts, as well as our own attempts (vide infra) to

synthesize the mixed-ligand Ru compounds using [TpRu(CO)2X] (X = Br, I) [3a,3d] were frustrated by

low or no conversion. However, we wish to report here that [TpRu(CO)(MeCN)X] (X = Br (1), I (2)) can be obtained readily and serve as a better starting material, leading to a series of new TpRu(CO) products.

2. Results and discussion

2.1. Preparation of [TpRu(CO)(MeCN)X] (X = Br (1),

I (2))

The Tp ligand, with its steric bulk (cone angle 180°) and unique electronic properties [5], is known to bias formation of the octahedral six-coordinate complexes of transition-metal atoms. It is hence not unexpected that no genuine seven-coordinate TpRu compounds were described in the literature [3,6]. This propensity of the ligand apparently accounts for the observed poor

* Corresponding author. Fax: + 886-6-2740552. E-mail address:[email protected](K.-B. Shiu).

0022-328X/02/$ - see front matter © 2002 Elsevier Science B.V. All rights reserved. PII: S 0 0 2 2 - 3 2 8 X ( 0 1 ) 0 1 4 1 7 - 6

reactivity of [TpRu(CO)2X] (X = Br, I) toward various

nucleophiles even under forced conditions. Thus, it usually allows only a partial conversion (ca. 30 – 50%), shown in the sequentially measured solution IR spectra, from [TpRu(CO)₂X] into other derivatives, even when the reaction mixture of [TpRu(CO)₂X] and nucleophiles in MeCN was heated at 82 °C for 3 days. Unfortu-nately, there were for many years no reports in the literature concerning any other {TpRu(CO)} complexes as good starting material [3]. We have now found that employment of [TpRu(CO)(MeCN)X] (X = Br (1), I (2)), prepared in a high yield from decarbonylation of [TpRu(CO)2X] with Me3NO in MeCN, as the starting

compounds can allow a complete conversion into the derived products. Apparently compounds 1 and 2 are the lightly stabilized complexes [7], and can serve as a good starting material leading to other substituted compounds.

2.2. Formation of monomeric TpRu(CO) complexes

No apparent reaction between [TpRu(CO)2X] and

neutral alkyl isocyanides in MeCN was observed, mon-itored by sequential solution IR spectra, even under reflux for a week. However, treatment of 1 and 2 with a slight excess of RNC under reflux for 12 h gave the expected complexes [TpRu(CO)(CNR)X] (X = Br, R = PhCH2 (3),

t

Bu (4); X = I, R = PhCH2 (5),

t

Bu (6)) in 60 – 70% yield. Likewise, reaction between 2 and anionic dialkyldithiocarbamate produced as expected [TpRu(CO)(h2_-S

2CNR2)] (R%=Me (7), Et (8)) in a

satisfactory yield within a reasonable period of time.

The monomeric feature of 8 was also confirmed by its crystal structure (Fig. 1). The CN distance of the coordinated diethyldithiocarbamate, d(C(11)N(7))= 1.329(3) A, , is within the typical range of 1.31–1.36 A, [8] for containing a partial double-bond character, and the distance is found compatible with the CN stretch-ing frequency of 1501 cm− 1 _{measured in CH}

2Cl2.

2.3. Formation of dimeric TpRu(CO) complexes

Prior to studying the reactions between [TpRu(CO)-(MeCN)X] and thiolates, it was expected to obtain dimeric {Tp2Ru2} products with exclusively

trans-dis-posed Tp ligands, based on the steric bulk of this ligand. However, to our surprise, seven different prod-ucts were obtained with five cis and two trans com-pounds, containing one and two thiolato bridges: (cis)-[Tp₂Ru₂(CO)(m-X)(m-SR)] (X=I, R=i_{Pr (11);}

X = Br, R =t_{Bu (13); X = I, R =}t_{Bu (14)), (trans,}

anti-1)-[Tp₂Ru₂(CO)₂(m-Si_Pr)

2] (9), (cis, syn)-[Tp2Ru2(CO)2

-(m-Si_Pr)

2] (10), (trans, anti-1)-[Tp2Ru2(CO)2(m-StBu)2]

(12), and (cis, anti-2)-[Tp2Ru2(CO)2(m-SiPr)(m-StBu)]

(15). For the compounds containing two thiolato bridges, except the common syn orientation [9], there are two types of anti orientations: anti-1 for the geome-try containing one thiolato R group above plane Ru2S2

and the other group below, and anti-2 for the geometry with one thiolato R group below plane Ru2S2 and the

other group coplanar with Ru2S2 (Chart 1).

[Tp2Ru2(CO)2(m-Br)(m-S

i

Pr)] was not isolated in the reaction between 1 and i_{PrSH – Et}

3N. Clearly with the

exception of the steric effect of the Tp ligand, the formation of different products is also dependent on the effect of the halo ligand, X, of [TpRu(CO)-(MeCN)X] and that of the thiolato R group. Using a thiol reagent with a bulkier t_{Bu group, or using 2 with}

a larger iodo ligand, mono-thiolato products [Tp2Ru2(CO)2(m-X)(m-SR)] (X=I, R=iPr (11); X = Br,

R =t_{Bu (13); X = I, R =}t_{Bu (14)) were then observed.}

The geometries of these mono-thiolato complexes are similar to each other: each displays two carbonyl stretching bands in the IR spectrum, and one set of six doublets in an intensity ratio of 1:1:1:1:1:1 for hydrogen nuclei at the 3- and 5-positions of the pyrazolyl rings of the Tp ligand and a set of three triplets in an intensity ratio of 1:1:1 for those at the 4-positions in the 1

H-NMR spectrum. The crystal structure of 14 was deter-mined, and two Tp ligands were found to adopt the cis positions (Fig. 2). Sum in the metallacycle Ru(1)/S(1)/ Ru(2)/I is 345.50°, deviated largely from the theoretical value of 360° required for planar four-membered ring. It indicates that the four atoms, Ru2SX (X = I, in 14),

are not coplanar. Apparently, [TpRu(CO)(MeCN)X] reacted with RSH – Et3N to form an intermediate

[TpRu(CO)(SR)] first, and either dimerization of this intermediate or a subsequent reaction between

[TpRu-Fig. 1. ORTEP drawing of [TpRu(CO)(h2_-S

2CNEt2)] (8). Thermal

ellipsoids are drawn at the 50% probability level. Selected bond distances (A, ) and angles (°) are as follows: Ru(1)C(1), 1.834(3); Ru(1)N(1), 2.158(2); Ru(1)N(3), 2.101(2); Ru(1)N(5), 2.113(2); Ru(1)S(1), 2.3811(7); Ru(1)S(2), 2.4013(7); S(1)C(11), 1.725(3); S(2)C(11), 1.724(3); C(11)N(7), 1.329(3); C(1)O(1), 1.146(3); S(1)Ru(1)S(2), 72.93(2); Ru(1)C(1)O(1), 178.7(2); S(1)C(11) S(2), 123.9(2).

Chart 1.

(CO)(SR)] and [TpRu(CO)(MeCN)X] then took place to form [Tp2Ru2(CO)2(m-SR)2] and [Tp2Ru2(CO)2

(m-X)(m-SR)] (Scheme 1).

The reaction of 1 or 2 withi_{PrSH – Et}

3N was heated

in either THF or 1,2-dimethoxyethane under reflux, giving several products. Two typical reactions as shown in the Section 3 produced (trans, anti-1)-[Tp2Ru2

-(CO)2(m-SiPr)2] (9), (cis, syn)-[Tp2Ru2(CO)2(m-SiPr)2]

(10), and (cis)-[Tp2Ru2(CO)2(m-I)(m-SiPr)] (11). The

crystal structures of 9 (Fig. 3) and 10 (Fig. 4) were also determined by X-ray diffraction methods to confirm the (trans, anti-1) and (cis, syn-1) geometries assigned for 9 and 10, respectively. Sum in the metallacycle Ru(1)/ S(1A)/Ru(1A)/S(1) is 360° in 9, indicating that unlike Ru2SX in 14 (Fig. 2), the four atoms, Ru2S2 in 9 (Fig.

3) are coplanar, with one thiolato R group above this plane and the other below, probably due to the fact that this structure contains a crystallographically im-posed inversion center. Although, structure 10 has a crystallographically imposed mirror plane containing two sulfur atoms, S(1) and S(2), and two carbon atoms, C(11) and C(13), the four Ru₂S₂ atoms (i.e. Ru(1), Ru(1A), S(1), and S(2)), in 10 are not coplanar with sum in the metallacycle Ru(1)/S(2)/Ru(1A)/S(1) of 356.94°.

Except the mono-thiolato complexes, (cis)-[Tp2Ru2

-(CO)2(m-Br)(m-S

t

Bu)] (13) and (cis)-[Tp2Ru2(CO)2

(m-I)(m-St

Bu)] (14), (trans, anti-1)-[Tp2Ru2(CO)2(m-S

t

Bu)2]

(12) was separated successfully from the reactions of 1

or 2 with t

BuSH – Et3N. Compound 12 shows similar

features in both IR and1_{H-NMR spectra to compound} 9. Like 9, compound 12 also adopts a (trans, anti-1)

geometry as confirmed by X-ray diffraction methods.

Fig. 2.ORTEPdrawing of (cis)-[Tp2Ru2(CO)2(m-I)(m-StBu)] (14).

Ther-mal ellipsoids are drawn at the 50% probability level. Hydrogen atoms are omitted for clarity. Selected bond distances (A, ) and angles (°) are as follows: Ru(1)C(1), 1.844(8); Ru(1)N(1), 2.102(6); Ru(1)N(3), 2.099(6); Ru(1)N(5), 2.148(6); Ru(1)S(1), 2.423(2); Ru(1)I(1), 2.7288(7); C(1)O(1), 1.115(10); Ru(2)C(2), 1.825(9); Ru(2)N(7), 2.089(6); Ru(2)N(9), 2.100(7); Ru(2)N(11), 2.173(6); Ru(2)S(1), 2.452(2); Ru(2)I(1), 2.7338(7); C(2)O(2), 1.152(12); S(1)C(21), 1.828(8); S(1)Ru(1)I(1), 76.07(5); Ru(1)I(1)Ru(2), 89.60(2); I(1)Ru(2)S(1), 75.53(5); Ru(2)S(1)Ru(1), 104.30(8); Ru(1)C(1)O(1), 173.2(8); Ru(2)C(2)O(2), 171.4(9).

Scheme 1.

fact that the t

Bu singlet for 14 or 13 is at the further upfield position, with l 0.88 for 14 and l 1.02 for 13 relative to that ofl 1.74 for 12, is probably caused by the different shielding ring-current effect of the nearby pyrazolyl moieties of the Tp ligands.

To obtain some diruthenium complexes with mixed thiolato ligands, the reaction of 1 with i_PrSH, t_BuSH,

and Et₃N was also carried out in 1,2-dimethoxyethane. Since a t

Bu group is much larger than an i

Pr group, more t

BuSH than i

PrSH was used in the reaction. Except three homo-dithiolato compounds of 9, 10, and

12, only one hetero-dithiolato product [Tp2Ru2(CO)2(

m-Si_Pr)(m-St_{Bu)] (15) was isolated. The crystal structure of}

15 was determined and found to contain a

crystallo-graphically imposed mirror plane consisting of atoms S(1), S(2), C(11), C(13) and C(15) (Fig. 6). It is worthy to note that structure 15 adopts a unique (cis, anti-2) geometry with a large R group,t

Bu, rather than a small one,i_{Pr, at a position close to the plane Ru}

2S2(Fig. 6).

Like structure 10, the four atoms, Ru2S2, in structure 15 are not coplanar with sum in the metallacycle Ru(1)/

S(1)/Ru(1A)/S(2) of 351.03°. In order to find an expla-nation for 15 to adopt such a geometry, structures, 9,

10, 12, 14, and 15 were compared with each other

again, and a unique feature was then rediscovered as shown in Scheme 2. If the carbon and oxygen atoms of each carbonyl in these structures, the ligated Ru atom, and one trans-pyrazolyl nitrogen atom are connected in one imaginary line segment, two such segments in 9 and

12 are found to be almost parallel to each other, but the

two segments in 10, 14, and 15 are not, forming a small angle of 2.6° in 10, 8.0° in 14 and 4.4° in 15. Appar-ently, the molecular strain resulting from repulsive non-bonded interactions between a bulky Tp ligand and a thiolato group (or a halo group) cannot be relieved in a

Fig. 3.ORTEPdrawing of (trans, anti-1)-[Tp2Ru2(CO)2(m-SiPr)2] (9).

Thermal ellipsoids are drawn at the 30% probability level. Hydrogen atoms are omitted for clarity. Selected bond distances (A, ) and angles (°) are as follows: Ru(1)C(1), 1.826(3); Ru(1)N(1), 2.165(2); Ru(1)N(3), 2.104(3); Ru(1)N(5), 2.127(3); Ru(1)S(1), 2.4264(7); S(1)C(11), 1.858(3); C(1)O(1), 1.152(4); S(1)Ru(1)S(1A), 79.90(3); Ru(1)S(1)Ru(1A), 100.10(3); Ru(1)C(1)O(1), 172.6(3).

The asymmetric unit of the single crystal used contains one half dinuclear molecule for 9 (Fig. 3), but two such half molecules, 12A and 12B, for 12. Both 9 and 12 contain a crystallographically imposed inversion center. Although structure 12A is similar to structure 12B, two methyl groups of the t

Bu group in 12B were found to be disordered in two positions with an occupancy ratio of 0.726:0.274. Molecule 12A was drawn in Fig. 5. The

Fig. 4.ORTEPdrawing of (cis, syn)-[Tp2Ru2(CO)2(m-SiPr)2] (10). Thermal ellipsoids are drawn at the 50% probability level. Hydrogen atoms are

omitted for clarity. Selected bond distances (A, ) and angles (°) are as follows: Ru(1)C(1), 1.820(6); Ru(1)N(1), 2.098(4); Ru(1)N(3), 2.113(4); Ru(1)N(5), 2.192(4); Ru(1)S(1), 2.4146(12); Ru(1)S(2), 2.415(2); S(1)C(11), 1.840(7); C(1)O(1), 1.155(7); S(1)Ru(1)S(2), 80.49(6); Ru(1)S(1)Ru(1A), 98.00(6); Ru(1)S(2)Ru(1A), 97.96(8); Ru(1)C(1)O(1), 172.6(5).

Fig. 5.ORTEPdrawing of (trans, anti-1)-[Tp2Ru2(CO)2(m-S

t_Bu)

2] (12A). Thermal ellipsoids are drawn at the 50% probability level. Hydrogen atoms

are omitted for clarity. Selected bond distances (A, ) and angles (°) are as follows: Ru(1)C(1), 1.829(3); Ru(1)N(1), 2.167(3); Ru(1)N(3), 2.139(3); Ru(1)N(5), 2.107(3); Ru(1)S(1), 2.4527(8); S(1)C(11), 1.895(3); C(1)O(1), 1.162(4); S(1)Ru(1)S(1A), 78.87(3); Ru(1)S(1)Ru(1A), 101.13(3); Ru(1)C(1)O(1), 173.3(3).

Fig. 6.ORTEPdrawing of (cis, anti-2)-[Tp2Ru2(CO)2(m-SiPr)(m-StBu)] (15). Thermal ellipsoids are drawn at the 50% probability level. Hydrogen

atoms are omitted for clarity. Selected bond distances (A, ) and angles (°) are as follows: Ru(1)C(1), 1.817(5); Ru(1)N(1), 2.103(4); Ru(1)N(3), 2.186(4); Ru(1)N(5), 2.126(4); Ru(1)S(1), 2.4222 (11); Ru(1)S(2), 2.4040(11); S(1)C(11), 1.832(9); S(2)C(13), 1.828(7); C(1)O(1), 1.150(5); S(1)Ru(1)S(2), 75.40(5); Ru(1)S(1)Ru(1A), 99.60(6); Ru(1)S(2)Ru(1A), 100.63(6); Ru(1)C(1)O(1), 172.1(4).

trans geometry such as 9 or 12. However, the strain can

be relieved more or less in a cis geometry such as 10,

14, or 15 by twisting two line segments toward the

carbonyl side. This twisting also shifts four atoms of Ru2SX in 14 or Ru2S2 in 10 and 15 away from

copla-narity (Scheme 2). The strain relieving is probably effective, and there are five-versus-two cis reaction products favorably formed from 1 and 2 Chart 1. By comparison of the structure models for 15 and a hypo-thetical one, 15%, with i_{Pr and} t_{Bu positions}

inter-changed, there is non-bonding repulsive interaction between the lone pair electrons of the S atom of i

PrS and a methyl group oft

BuS.

2.4. Reaction of (cis)-[Tp2Ru2(CO)2(v-I)(v-S i

Pr)] (11)

with Me3NO

Following a recent focus of research on the

forma-tion of a transiforma-tion-metal sulfenate (MS(O)R) [10], oxygenation of (cis)-[Tp2Ru2(CO)2(m-I)(m-SiPr)] (11)

with trimethylamine oxide was also carried out. Two new carbonyl stretching bands at 1979s and 1945m cm− 1 _{and one strong band at 943 cm}− 1_{, assigned to}

w(SO), appeared almost immediately as shown in an IR spectrum measured in CH₂Cl₂. The ruthenium sulfe-nate, (cis)-[Tp2Ru2(CO)2(m-I)(m-S(O)iPr)] (16) was

ob-tained as the only product, which is the first diruthenium sulfenate, to the best of our knowledge [11]. The asymmetric unit of the single crystal used contains two molecules, 16A and 16B, for 16. Both structures are similar to each other, and only structure

16A is shown in Fig. 7. The molecular structure

confi-rms that the mono-oxygenation process is probably stereo- and chemospecific to give the product with an SO bond at an endo rather than exo position with respect to carbonyls (Scheme 3). The SO distances of

1.509(6) A, in 16A and 1.534(6) A, in 16B are similar to that of 1.548(8) A, in a nickel sulfenate complex [10a].

3. Experimental

All solvents were dried and purified by standard methods and were freshly distilled under N2

immedi-ately before use. All reactions and manipulations were carried out in standard Schlenk ware, connected to a switchable double manifold providing vacuum and N2.

The compound [TpRu(CO)2X] (X = Br, I) was

pre-pared by the literature method [3d]. Reagents were used as supplied by Aldrich, Fluka, or Strem. 1_{H- and} 31_{P-NMR spectra were measured on a Brueker}

AMC-400 (1_{H, 400 MHz;}31_{P, 162 MHz) NMR spectrometer.} 1_{H chemical shifts (l in ppm, J in Hz) are defined as}

positive downfield relative to internal Me4Si (TMS) or

the deuterated solvent, while 31_{P chemical shifts are}

referred to external 85% H3PO4. The IR spectra were

recorded on a BioRad FTS 175 instrument. The follow-ing abbreviations were used: s, strong (IR); m, medium; w, weak; s, singlet (NMR); d, doublet; br, broad; m, multiplet. Microanalyses were carried out by the staff of the Microanalytical Service of the Department of Chemistry, National Cheng Kung University.

3.1. Synthesis of [TpRu(CO)(NCMe)X] (X = Br (1), I

(2))

A solution of complex [TpRu(CO)₂X] (1.90 mmol) in MeCN (45 ml) was added dropwise with the Me3NO

solution, prepared from 0.245 g of Me3NO·2H2O (2.21

mmol) in 30 ml of MeCN. The solution was stirred at room temperature (r.t.) for 10 min, and the solvent was removed under vacuum. Recrystallization from CH2Cl2– MeOH gave pure product.

[TpRu(CO)-(NCMe)Br] (1): yellow; yield 87%. Anal. Calc. for C12H13BBrN7ORu: C, 31.13; H, 2.83; N, 21.17. Found: C, 31.09; H, 2.87; N, 21.13%.1_{H-NMR (CDCl} 3):l 2.33 (s, 3H), 6.15 (t, 1H, 3_J H,H= 2.2), 6.22 (t, 1H, 3JH,H= 2.1), 6.33 (t, 1H,3_J H,H= 2.0), 7.53 (d, 1H,3JH,H= 2.0), 7.61 (d, 1H, 3_J H,H= 2.4), 7.69 (d, 1H,3JH,H= 2.4), 7.73 (d, 1H, 3_J H,H= 2.4), 7.80 (d, 1H, 3JH,H= 2.0), 8.16 (d, 1H, 3_J H,H= 2.0). IR (CH2Cl2):wBH, 2495w;wCO, 1981s

cm− 1_{. [TpRu(CO)(NCMe)I] (2): yellow; yield 84%.}

Anal. Calc. for C12H13BIN7ORu: C, 28.26; H, 2.57; N,

19.22. Found: C, 28.03; H, 2.54; N, 18.95%. 1_H-NMR (CDCl3): l 2.40 (s, 3H), 6.13 (t, 1H, 3JH,H= 2.8), 6.23 (t, 1H, 3_J H,H= 2.8), 6.32 (t, 1H, 3JH,H= 2.8), 7.54 (d, 1H,3_J H,H= 2.4), 7.60 (d, 1H,3JH,H= 2.4), 7.67 (d, 1H, 3_J H,H= 2.4), 7.70 (d, 1H, 3JH,H= 2.4), 7.89 (d, 1H, 3_J H,H= 2.4), 8.28 (d, 1H, 3JH,H= 2.4). IR (CH2C12): wBH, 2495w;wCO, 1979s cm− 1. 3.2. Synthesis of [TpRu(CO)(CNR)Br] (R = PhCH2 (3), t_{Bu (4)) and [TpRu(CO)(CNR)I] (R = PhCH} 2 (5), t_{Bu (6))}

These yellow compounds were prepared by using a similar procedure described below for the synthesis of compound 6. tert-Butylisocyanide (0.093 g, 1.10 mmol) was added to a stirred solution of 2 (0.510 g, 1.00 mmol) in 30 ml of THF. The solution was then heated under reflux for 12 h. The volatiles were stripped off under vacuum. Recrystallization from CH2Cl2– MeOH

gave 0.362 g of 6. Yield 66%. [TpRu(CO)(CNCH2 Ph)-Scheme 2.

Fig. 7.ORTEPdrawing of (cis)-[Tp2Ru2(CO)2(m-I)(m-S(O)iPr)] (16A).

Thermal ellipsoids are drawn at the 30% probability level. Hydrogen atoms are omitted for clarity. Selected bond distances (A, ) and angles (°) are as follows: Ru(1)C(1), 1.840(10); Ru(1)N(1), 2.171(8); Ru(1)N(3), 2.129(8); Ru(1)N(5), 2.066(8); Ru(1)S(1), 2.347(2); Ru(1)I(1), 2.7054(12); S(1)C(21), 1.828(10); C(1)O(1), 1.137(12); Ru(2)C(2), 1.840(10); Ru(2)N(7), 2.163(8); Ru(2)N(9), 2.142(8); Ru(2)N(11), 2.085(8); Ru(2)S(1), 2.344(2); Ru(2)I(1), 2.7082(11); S(2)C(44), 1.817(10); C(2)O(2), 1.139(12); S(1)O(3), 1.509(6); O(3)S(1)C(21), 104.1(4); S(1)Ru(1)I(1), 82.35(6); Ru(1) S(1)Ru(2), 104.18(9); S(1)Ru(2)I(1), 82.33(6); Ru(2)I(1)Ru(1), 86.26(3); Ru(1)C(1)O(1), 170.0(9); Ru(2)C(2)O(2), 174.8(9).

Scheme 3.

Br] (3): Anal. Calc. for C18H17BBrN7ORu: C, 40.10; H,

3.18; N, 18.19. Found: C, 39.70; H, 3.22; N, 17.88%. 1_{H-NMR (CD} 2Cl2):l 5.07 (s, 2H), 6.20 (t, 1H,3JH,H= 2.3), 6.27 (m, 2H), 7.33 (m, 6H), 7.71 (m, 3H), 7.95 (m, 2H). IR (CH2Cl2): wBH, 2493; wCN, 2184; wCO, 1995s cm− 1_{. [TpRu(CO)(CN}t

Bu)Br] (4): Anal. Calc. for C15H19BBrN7ORu: C, 35.67; H, 3.79; N, 19.41. Found: C, 35.58; H, 3.85; N, 19.28%.1_{H-NMR (CDCl} 3):l 1.53 (s, 9H), 6.21 (br, 1H), 6.26 (br, 1H), 6.30 (br, 1H), 7.48 (br, 1H), 7.70 (m, 3H), 7.92 (br, 1H), 7.98 (br, 1H). IR (CH₂Cl₂):w, 2495; w_CN, 2172s;w_CO, 1991s cm− 1_.

[TpRu-(CO)(CNCH2Ph)I] (5): Anal. Calc. for C18H17BIN7

-ORu: C, 36.88; H, 2.92; N, 16.73. Found: C, 36.81; H, 2.95; N, 16.67%. 1_{H-NMR (C} 3H6O-d6): l 5.33 (s, 2H), 6.27 (t, 1H, 3_J H,H= 2.2), 6.30 (m, 2H), 7.37 (m, 3H), 7.55 (m, 2H), 7.76 (d, 1H, 3_J H,H= 1.8), 7.85 (br, 3H), 7.89 (d, 1H,3_J H,H= 2.4), 8.04 (d, 1H,3JH,H= 1.8), 8.07 (d, 1H, 3_J H,H= 1.8). IR (CH2Cl2): wBH, 2492w; wCN, 2182s; wCO, 1993s cm− 1. [TpRu(CO)(CN t Bu)I] (6): Anal. Calc. for C15H19BIN7ORu: C, 32.63; H, 3.47; N,

17.76. Found: C, 32.26; H, 3.45; N, 17.57%.1_H-NMR (C3H6O-d6): l 1.55 (s, 2H), 6.28 (t, 1H, 3JH,H= 2.2), 6.29 (t, 1H,3_J H,H= 2.2), 6.31 (t, 1H,3JH,H= 2.2), 7.76 (d, 1H, 3_J H,H= 1.6), 7.84 (d, 1H, 3JH,H= 2.4), 7.85 (d, 1H,3_J H,H= 2.4), 7.88 (d, 1H,3JH,H= 2.0), 8.02 (d, 1H, 3_J H,H= 1.6), 8.12 (d, 1H, 3JH,H= 2.0). IR (CH2Cl2): wBH, 2493w; wCN, 2168s;wCO, 1989s cm− 1. 3.3. Preparation of[TpRu(CO)(p2_-S 2CNR2)] (R%=Me (7), Et (8))

Compound 7 and 8 were prepared similarly by using the procedure described below for the synthesis of the

yellow – green compound 7. Na+_S

2CNMe2− (0.082 g,

0.573 mmol) was added to a stirred solution of 2 (0.240 g, 0.481 mmol) in 30 ml of MeOH. The solution was then heated under reflux for 14 h. The volatiles were stripped off under vacuum. Recrystallization from CH2Cl2– MeOH gave 0.171 g. Yield 79%.

[TpRu(CO)(h2_-S

2CNMe2)] (7): yellow – green. Anal.

Calc. for C13H16BN7ORuS2: C, 33.77; H, 3.48; N,

21.20. Found: C, 33.69; H, 3.45; N, 21.04%. 1_H-NMR (C3H6O-d6): l 3.36 (s, 6H), 6.25 (t, 2H, 3JH,H= 2.2), 6.29 (t, 1H, 3_J H,H= 2.1), 7.63 (d, 2H,3JH,H= 2.1), 7.88 (m, 4H). IR (CH₂Cl₂): w_BH, 2487w; w_CO, 1949s; w_CN, 1501s cm− 1_{. [TpRu(CO)(h}2_-S

2CNEt2)] (8): pale green,

yield 79%. Anal. Calc. for C15H20BN7ORuS2: C, 36.74;

H, 4.11; N, 19.99. Found: C, 36.63; H, 4.03; N, 19.88%. 1_{H-NMR (C} 3H6O-d6): l 1.33 (t, 6H, 3JH,H= 7.2), 3.84 (m, 4H), 6.25 (t, 2H, 3_J H,H= 2.1), 6.31 (t, 2H,3JH,H= 2.1), 7.62 (d, 2H, 3_J H,H= 2.0), 7.88 (m, 4H). IR (CH2Cl2): wBH, 2489w; wCO, 1947s; wCN, 1501s cm− 1.

3.4. Reaction of [TpRu(CO)(NCMe)Br] (1) with i

PrSH and Et3N

Compound 1 (0.293 g, 0.63 mmol),i_{PrSH (ca. 0.5 ml,}

5.22 mmol), Et3N (ca. 0.5 ml, 3.59 mmol) and

1,2-dimethoxyethane (20 ml) were heated under reflux for 20 h. The solvent and volatiles were then removed under vacuum, and the residue was taken up in a minimum amount o f CH₂Cl₂. The products were sepa-rated by thin-layer chromatography using CH2Cl2–

C6H14 mixed solvents to give 2.6 mg of (trans,

anti-1)-[Tp₂Ru₂(CO)₂(m-Si_Pr)

2] (9) (0.5%) and 109 mg

of (cis, syn)-[Tp2Ru2(CO)2(m-S

i

anti-1)-[Tp2Ru2(CO)2(m-S

i

Pr)2] (9): yellow. Anal. Calc.

for C26H34B2N12O2RU2S2: C, 37.42; H, 4.11; N, 20.14. Found: C, 37.24; H, 3.93; N, 20.02%. 1_H-NMR (CDC1₃): l 1.51 (d, 12H, 3_J H,H= 6.8), 4.20 (m, 2H), 6.17 (t, 2H), 6.18 (t, 2H), 6.29 (t, 2H), 7.59 (d, 2H, 3_J H,H= 2.0), 7.60 (d, 2H, 3JH,H= 2.0), 7.66 (d, 2H, 3_J H,H= 2.0), 7.67 (d, 2H, 3JH,H= 2.0), 7.73 (d, 2H, 3_J H,H= 2.0), 7.79 (d, 2H, 3JH,H= 2.0). IR (CH2Cl2): wBH, 2491w; wCO, 1962s cm− 1. (cis,

syn)-[Tp2Ru2(CO)2(m-SiPr)2] (10): orange – yellow. Anal.

Calc. for C26H34B2N12O2Ru2S2: C, 37.42; H, 4.11; N, 20.14. Found: C, 37.14; H, 4.08; N, 20.07%.1_H-NMR (CDCl3): l 0.50 (d, 12H, 3JH,H= 6.8), 2.70 (m, 2H), 6.18 (t, 4H), 6.45 (t, 2H), 7.61 (d, 4H,3_J H,H= 2.4), 7.82 (d, 2H, 3_J H,H= 2.0), 7.88 (d, 2H, 3JH,H= 2.4), 8.92 (d, 2H, 3_J H,H= 2.0). IR: wBH, 2487w; wCO, 1981sh, 1968s cm− 1 _{in CH} 2Cl2 and wBH, 2477w; wCO, 1989m, 1979s cm− 1_{in C} 6H14.

3.5. Reaction of [TpRu(CO)(NCMe)I] (2) with i_PrSH

and Et3N

Compound 2 (0.301 g, 0.59 mmol),i_{PrSH (ca. 0.5 ml,}

5.22 mmol), Et3N (ca. 0.5 ml, 3.59 mmol) and

1,2-dimethoxyethane (20 ml) were heated under reflux for 2 h. The solvent and volatiles were then removed under vacuum, and the residue was taken up in a minimum amount of CH2Cl2. The products were separated by

thin-layer chromatography using CH2Cl2– C6H14 mixed

solvents to give 9.3 mg of (trans,

anti-1)-[Tp₂Ru₂(CO)₂(m-Si_Pr)

2] (9) (1.9%), 53.4 mg of (cis,

syn)-[Tp₂Ru₂(CO)₂(m-Si_Pr)

2] (10) (10.8%), and 3.2 mg of

(cis)-[Tp₂Ru₂(CO)₂(m-I)(m-Si_{Pr)] (11) (0.7%).}

(cis)-[Tp₂Ru₂(CO)₂(m-I)(m-Si_{Pr)] (11): yellow – brown. Anal.}

Calc. for C23H27B2IN12O2Ru2S: C, 31.17; H, 3.07; N, 18.96. Found: C, 31.02; H, 3.07; N, 18.87%.1_H-NMR (CDCl3):l 0.89 (d, 6H,3JH,H= 6.4), 2.88 (m, 1H), 6.17 (t, 2H), 6.21 (t, 2H), 6.44 (t, 2H), 7.58 (d, 2H,3_J H,H= 2.4), 7.67 (d, 2H,3_J H,H= 2.4), 7.74 (d, 2H,3JH,H= 2.0), 7.80 (d, 2H,3_J H,H= 2.4), 7.94 (d, 2H,3JH,H= 2.0), 8.86 (d, 2H, 3_J H,H= 2.0). IR (CH2Cl2): wBH, 2489w; wCO, 1981s, 1949m cm− 1_.

3.6. Reaction of [TpRu(CO)(NCMe)Br] (1) with t BuSH

and Et₃N

Compound 1 (0.232 g, 0.50 mmol), t_{BuSH (ca. 0.5}

ml, 4.40 mmol), Et₃N (ca. 0.5 ml, 3.59 mmol) and 1,2-dimethoxyethane (30 ml) were heated under reflux for 44 h. The solvent and volatiles were then removed under vacuum, and the residue was taken up in a minimum amount of CH2Cl2. The products were

sepa-rated by thin-layer chromatography using CH2Cl2–

C6H14 mixed solvents to give 0.3 mg of (trans,

anti-1)-[Tp2Ru2(CO)2(m-S t Bu)2] (12) (0.07%) and 11.1 mg of (cis)-[Tp2Ru2(CO)2(m-Br)(m-S t Bu)2] (13) (2.6%).

(trans, anti-1)-[Tp2Ru2(CO)2(m-S

t

Bu)2] (12): yellow.

Anal. Calc. for C28H38B2N12O2Ru2S2: C, 38.99; H, 4.44;

N, 19.49. Found: C, 38.84; H, 4.43; N, 19.37%. 1 H-NMR (CDCl₃): l 1.74 (s, 18H), 6.18 (m, 4H), 6.30 (t, 2H), 7.59 (m, 4H), 7.66 (m, 4H), 7.73 (d, 2H, 3_J H,H= 2.4), 7.84 (d, 2H, 3_J H,H= 2.0). IR (CH2Cl2): wBH, 2489w; wCO, 1964s cm− 1. (cis)-[Tp2Ru2(CO)2( m-Br)(m-St_Bu)

2] (13): orange – yellow. Anal. Calc. for

C24H29B2BrN12O2Ru2S: C, 33.78; H, 3.43; N, 19.70. Found: C, 33.67; H, 3.43; N, 19.62%. 1_H-NMR (CDCl3): l 1.02 (s, 9H), 6.16 (t, 2H), 6.18 (t, 2H), 6.50 (t, 2H), 7.57 (d, 2H, 3_J H,H= 2.4), 7.76 (d, 2H, 3JH,H= 2.4), 7.77 (d, 2H,3_J H,H= 2.0), 7.83 (d, 4H,3JH,H= 2.0), 7.92 (d, 2H, 3_J H,H= 2.0), 9.07 (d, 2H, 3JH,H= 2.0). IR (CH2Cl2):wBH, 2489w;wCO, 1976s, 1935m cm− 1.

3.7. Reaction of [TpRu(CO)(NCMe)I] (2) with t_BuSH

and Et₃N

Compound 2 (0.311 g, 0.61 mmol), t_{BuSH (ca. 0.5}

ml, 4.40 mmol), Et3N (ca. 0.5 ml, 3.59 mmol) and

1,2-dimethoxyethane (20 ml) were heated under reflux for 16 h. The solvent and volatiles were then removed under vacuum, and the residue was taken up in a minimum amount of CH2Cl2. The products were

sepa-rated by thin-layer chromatography using CH2Cl2–

C6H14 mixed solvents to give 1.0 mg of (trans,

anti-1)-[Tp2Ru2(CO)2(m-S

t

Bu)2] (12) (0.19%) and 48.7

mg of (cis)-[Tp2Ru2(CO)2(m-I)(m-S

t

Bu)2] (14) (8.9%).

(cis)-[Tp2Ru2(CO)2(m-I)(m-S

t

Bu)2] (14): yellow – brown.

Anal. Calc. for C₂₄H₂₉B₂IN₁₂O₂Ru₂S: C, 32.02; H, 3.25; N, 18.67. Found: C, 31.98; H, 3.23; N, 18.62%. 1 H-NMR (CDCl₃): l 0.88 (s, 9H), 6.13 (t, 2H), 6.20 (t, 2H), 6.50 (t, 2H), 7.55 (d, 2H,3_J H,H= 2.4), 7.66 (d, 2H, 3_J H,H= 2.4), 7.81 (d, 2H, 3JH,H= 2.0), 7.82 (d, 2H, 3_J H,H= 2.4), 7.99 (d, 2H, 3JH,H= 2.0), 9.10 (d, 2H, 3_J H,H= 2.0). IR (C6H14):wBH, 2481w;wCO, 1985s, 1966s cm− 1_.

3.8. Reaction of [TpRu(CO)(NCMe)Br] (1) with i PrSH, t BuSH and Et3N Compound 1 (0.262 g, 0.57 mmol),i PrSH (ca. 0.1 ml, 1.04 mmol), t

BuSH (ca. 0.5 ml, 4.40 mmol), Et3N (ca.

0.5 ml, 3.59 mmol) and 1,2-dimethoxyethane (15 ml) were heated under reflux for 25 h. The solvent and volatiles were then removed under vacuum, and the residue was taken up in a minimum amount of CH₂Cl₂. The products were separated by thin-layer chromato-graphy using CH2Cl2– C6H14mixed solvents to give 8.1

mg of (trans, anti-1)-[Tp2Ru2(CO)2(m-SiPr)2] (9) (1.7%),

42.9 mg of (cis, syn)-[Tp2Ru2(CO)2(m-SiPr)2] (10) (9%),

4.1 mg of (trans, anti-1)-[Tp2Ru2(CO)2(m-StBu)2] (12)

(0.8%), and 4.6 mg of (cis, anti-2)-[Tp2Ru2(CO)2

-(m-Si_Pr)(m-St

Bu)] (15) (0.5%). (cis, anti-2)-[Tp2Ru2

-(CO)2(m-S

i_Pr)(m-St

Table 1 Crystal data Compound 8 9 ·2CH 2 Cl 2 10 ·3 /2CH 2 Cl 2 12 14 C24 H27 B2 IN 12 O2 -C28 H36 B2 N12 O2 Ru 2 -C C27 H36.5 B2 Cl 3 N12 -Empirical formula C28 H34 B2 Cl 4 N12 -C15 H10 BN 7 O-S2 Ru 2 S O2 Ru 2 S2 O2 Ru 2 S2 RuS 2 898.30 1000.35 955.41 Formula w eight 480.30 860.57 295(2) 295(2) 295(2) 293(2) 150(1) Temperature (K) Monoclinic, P 21 /c Triclinic, P 1( Monoclinic, P 21 /c Space group T riclinic, P 1( Orthorhombic, Pnnm a (A ,) 12.1281(7) 9.2217(1) 13.0914(1) 10.0740(1) 16.163(2) 12.329(1) b (A ,) 10.6930(6) 11.4607(1) 16.2025(3) 9.4158(1) 17.812(2) 15.8813(9) 11.9236(2) 18.3263(3) 17.4487(1) c (A ,) 90 90 83.599(1) 90 80.775(1) h (° ) 98.909(2) 78.960(1) i (° ) 90 86.249(1) 104.096(1) 64.986(1) 90 k (° ) 9 0 80.852(1) 90 3506.6(6) V (A , 3) 1997.6(2) 1784.66(3) 3887.3(1) 1014.58(2) 4 4 14 2 Z 1.702 1.597 1.637 1.633 1.601 Dcalc (g cm − 3) 1.1842 1.009 1.134 v (Mo – Ka )( m m − 1) 1.013 1.154 1752 952 500 1918 868 F (000) 0.40 × 0.12 × 0.10 0.30 × 0.10 × 0.05 0.40 × 0.40 × 0.20 0.30 × 0.30 × 0.30 0.22 × 0.20 × 0.16 Crystal size (mm) 3 – 57 2 – 55 Unit cell determination 2q range (° )3 – 56 3 – 55 3 – 57 9 13, 9 15, 9 22 9 21, 9 15, 9 22 (h , k , l) range 9 15, 9 13, 9 21 9 12, 9 12, 9 15 9 16, 9 21, 9 22 20 364 No. of measured re fl ections 11 722 15 934 21 802 10 634 7755 (\ 2| ) 4453 (\ 2| ) 4576 (\ 2| ) 4465 (\ 2| ) 7918 (\ 2| ) Observed re fl ections (N o ) R a, Rw a 0.0292, 0.0650 0.0349, 0.0985 0.0525, 0.1258 0.0343, 0.0795 0.056, 0.1708 SHELXTL-PLUS Re fi nement program SHELXTL -PLUS NRCVAX SHELXTL-PLUS NRCVAX 398 244 235 243 462 No. of re fi ned parameters (N p ) [| 2(F o ) Weighting scheme [| 2(F o ) [| 2(F o )] − 1 [| 2(F o )] − 1 [| 2(F o )] − 1 + 0.0009 Fo 2] − 1 + 0.0007 Fo 2] − 1 1.068 0.944 1.045 1.121 1.034 Goodness-of-fi t a 3.828 (D z )max (e A, 3) 1.652 0.381 1.278 1.610 (D z )min (e A, 3) − 0.319 − 0.818 − 1.394 − 0.811 − 0.940 aR = [ Fo − Fc /  Fo ]. Rw = [ … ( Fo − Fc ) 2/ … Fo  2] 1 /2. GOF = [ …  Fo − Fc  2/N o − Np ] 1 /2.

for C27H36B2N12O2Ru2S2: C, 38.22; H, 4.28; N, 19.81. Found: C, 38.06; H, 4.29; N, 19.77%. 1_H-NMR (CDCl₃): l 1.80 (s, 9H), 1.37 (d, 6H,3_J H,H= 6.8), 3.99 (m, 1H), 6.27 (t, 2H), 6.31 (t, 2H), 6.37 (t, 2H), 7.68 (d, 2H,3_J H,H= 2.0), 7.69 (d, 2H, 3JH,H= 2.0) 7.73 (d, 4H, 3_J H,H= 2.4), 7.75 (d, 2H, 3JH,H= 2.4), 8.55 (d, 2H, 3_J H,H= 2.0). IR (C6H14):wBH, 2481w;wCO, 1987s, 1979s cm− 1_.

3.9. Reaction of (cis)-[Tp2Ru2(CO)2(v-I)(v-SiPr)] (11)

with Me3NO

A solution of complex 11 (8.9 mg, 0.010 mmol) in CH2Cl2 (10 ml) was added with Me3NO·2H2O (51 mg,

0.46 mmol). The solution was stirred at r.t. for 1 h, and the solvent was removed under vacuum. Recrystalliza-tion from CH₂Cl₂– MeOH gave 6.1 mg of pure product

16. Yield 68%. Anal. Calc. for C₂₃H₂₇B₂IN₁₂O₃Ru₂S: C, 30.62; H, 3.02; N, 18.63. Found: C, 30.59; H, 3.17; N, 18.54%.1_{H-NMR (CDCl} 3): l 0.89 (d, 6H,3JH,H= 6.8), 2.87 (m, 1H), 6.16 (t, 2H), 6.20 (t, 2H), 6.43 (t, 2H), 7.57 (d, 2H,3_J H,H= 2.0), 7.63 (d, 2H,3JH,H= 2.0), 7.71 (d, dH, 3_J H,H= 2.0), 7.79 (d, 2H, 3JH,H= 2.0), 7.92 (d, 2H,3_J H,H= 2.0), 8.84 (d, 2H,3JH,H= 2.0). IR (CH2Cl2): wBH, 2491w; wCO, 1979s, 1945m;wSO, 943s cm− 1.

3.10. Single-crystal X-ray diffraction studies

Suitable single crystals of 8, 9, 10, 12, 14, 15, and 16 were grown from CH2Cl2– MeOH or CH2Cl2– C6H14at

r.t. and chosen for single crystal structure determina-tions. All the X-ray diffraction data were measured in frames with increasing… (width of 0.3° per frame) and with the scan speed at 20.00 s/frame on a Siemens SMART-CCD instrument, equipped with a normal fo-cus and 3 kW sealed-tube X-ray source. Empirical absorption corrections were carried out usingSHELXTL

-PC program for 8, 10, 14, and 15, andSADABSprogram

for 9, 12 and 16. These three structures were solved by the heavy-atom method and refined by a full-matrix least-squares procedure using NRCVAX [12]. Structures

8, 10, 14, and 15 were solved by direct methods and

refined by a full-matrix least-squares procedure using

SHELXTL-PLUS[13]. Neutral atom scattering factors for non-hydrogen atoms and the values for Df % and Df ¦ described in each software [12,13] were used. The other essential details of single-crystal data measurement and refinement are listed in Table 1. In structure 10, atom C(13) was found to contain 0.5 occupancy and both S(2)C(13) and C(13)C( 14) bond lengths were fixed with 1.808 and 1.525 A, , respectively, to allow a satisfac-tory refinement. Likewise, the C(17)Cl(3) bond length for one CH2Cl2contained in structure 15 was also fixed

with 1.89 A, . Several residual electron peaks with more than 1 e A, − 3_{were found with one peak close to atom}

Cl(2) in structure 9, one close to atom S(2) in structure

10, one close to atom Ru(1) in structure 12, one close to

atom S(1) in structure 14, and one close to atom I(1) in structure 16. The one close to S(1) in 14 has the largest value of 3.828 e A, − 3 _{while there is a hole with the}

largest (Dz)_min value of − 4.200 e A, − 3 _{close to I(1) in}

structure 16. Apparently both positions of the S(1) atom in 14 and the I(1) atom in 16 are slightly disordered.

4. Conclusions

In this work, we have demonstrated that [TpRu(CO)(MeCN)X] (X = Br (1), I (2)), prepared readily from [TpRu(CO)2X], can serve as a good

start-ing material leadstart-ing to a variety of substituted prod-ucts, including [TpRu(CO)(CNR)X] (X = Br, R = PhCH2(3); X = Br, R =

t_{Bu (4); X = I, R = PhCH}

2

(5), X = I, R =t_{Bu (6)), [TpRu(CO)(h}2_-S

2CNR2)] (R =

Me (7), Et (8)), (cis)-[Tp₂Ru₂(CO)₂(m-X)(m-SR)] (X=I, R =i_{Pr (11); X = Br, R =}t_{Bu (13); X = I, R =}t_Bu

(14)), (trans, anti-1)-[Tp2Ru2(CO)2(m-SiPr)2] (9), (cis,

syn)-[Tp2Ru2(CO)2(m-SiPr)2] (10), (trans,

anti-1)-[Tp2Ru2(CO)2(m-StBu)2] (12) and (cis, anti-2)-[Tp2Ru2

-(CO)2(m-SiPr)(m-StBu)] (15). Compound 11 reacts with

Me3NO to form stereo- and chemospecifically the first

diruthenium sulfenate, (cis)-[Tp2Ru2(CO)2

(m-I)(m-S(O)i_{Pr)] (16) with the SO bond at the endo position}

with respect to carbonyls.

5. Supplementary material

Crystallographic data for the structural analysis has been deposited with the Cambridge Crystallographic Data Centre, CCDC no. 173316, 173454, 173315, 173455, 173317, 173456, and 138612 for structures 8, 9,

10, 12, 14, 15, and 16. Copies of this information may

be obtained free of charge from The Director, CCDC, 12 Union Road, Cambridge CB2 1EZ, UK (Fax: + 44-1223-336033; e-mail: [email protected] or www:http://www.ccdc.cam.ac.uk).

Acknowledgements

Financial support for this work by the National Science Council of Republic of China (Contract NSC89-2113-M006-013) is gratefully acknowledged.

References

[1] S. Trofimenko, J. Am. Chem. Soc. 88 (1966) 1842.

[2] For the reviews on Tp complexes, see for example: (a) S. Trofimenko, Chem. Rev. 93 (1993) 943;

[5] M.D. Curtis, K.-B. Shiu, W.M. Butler, J.C. Huffman, J. Am. Chem. Soc. 108 (1986) 3335.

[6] C. Gemel, G. Trimmel, C. Slugovc, S. Kremel, K. Mereiter, R. Schmid, K. Kirchner, Organometallics 15 (1996) 3998.

lease 4.21; Siemens Analytical X-ray Instruments: Madison, WL, 1991. ;

(b) Siemens Analytical X-ray Instruments Inc., Karlsruhe, Ger-many, 1991.