Synthetic, X-ray diffraction, electrochemical, and density functional theoretical studies of (indenyl)ruthenium complexes containing dithiolate ligands

FULL PAPER

DOI: 10.1002/ejic.200700070

Synthetic, X-ray Diffraction, Electrochemical, and Density Functional

Theoretical Studies of (Indenyl)ruthenium Complexes Containing Dithiolate

Ligands

Sin Yee Ng,^[a]Jialin Tan,^[a]Wai Yip Fan,^[a]Weng Kee Leong,^[a]Lai Yoong Goh,*^[a]and

Richard D. Webster^[b]

Keywords: Ruthenium complexes / Dithiolates / Cyclic voltammetry / Density functional calculations

Halide substitution of the complexes [(Ind)Ru(L₂)X] {Ind = η⁵-

C₉H₇. 1: (L₂) = dppf [1,1Ј-bis(diphenylphosphanyl)ferrocene],

X = Cl; 2: (L₂) = dppm [1,1Ј-bis(diphenylphosphanyl)meth-

ane], X = Cl; and 18: (L₂) = (CO)₂, X = I} with the 1,1-dithiol-

ates ^–S₂CNR₂(dialkyl dithiocarbamates for R = Me, Et, and

C₅H₁₀), ^–S₂COR (alkyl xanthates for R = Et and iPr), and

^–S₂PR₂(dithiophosphinates for R = Et and Ph) showed that

the lability of the indenyl ligand is influenced by the nature

of both the coligand and the incoming dithiolate, as well as

the solvent. In addition to dithiolate derivatives, the reactions

also produced the hydride species [(Ind)Ru(diphos)H] in sol-

vent- and stoichiometry-dependent yields. The observed de-

pendence of lability of Ind on (L₂) follows the order, dppf Ͻ

dppm ≈ (CO)₂, in agreement with the electron-donor capa-

bility of L₂, as well as the estimation of lowest activation en-

ergy for the η⁵Ǟ η³ring slippage process in the series of

complexes [(Ind)Ru(L)₂(S₂COMe)] (L = PMeH₂, PH₃, CO) for

L = CO. The computational study also indicated an indenyl

lability order for dithiolate substitution (dithiocarbamate Ͼ

xanthate), in agreement with experimental findings. The

dissociation of the indenyl ligand in chloro substitution of 1

by ^–S₂CNEt₂was found to be exhaustive in a polar solvent

like MeOH, but only partial in CH₂Cl₂. Cyclic voltammetry

experiments indicated that [(Ind)Ru(dppf)(η¹-S₂COiPr)] (10)

and [(Ind)Ru(dppf)(η¹-S₂PPh₂)] (13) can be oxidized in one-

electron chemical irreversible or chemical reversible pro-

cesses, respectively (at a scan rate of 100 mV/s), at about 0 V

versus Fc/Fc⁺. Complex 13 underwent additional one-elec-

tron oxidation processes at +0.5 and +0.8 V versus Fc/Fc⁺.

The new complexes have all been characterized spectroscop-

ically, and some (four containing the indenyl ligand and three

of the non-indenyl type) by X-ray diffraction as well.

Germany, 2007)

Introduction

1,1-Dithiolate compounds represent a class of versatile

ligands, owing to the occurrence of resonance phenomena,

which result in electron delocalization, as depicted in

Scheme 1. Their coordination chemistry with the transition

metals commands much interest, on account of the rich di-

versity of the complexes and their numerous and potential

applications in industry and agriculture.^[1]

Our work on some of these ligands was directed at their

reactivity in the coordination environment of CpCr(CO)_n

(n = 2 or 3),^[2](HMB)Ru(dppf), and CpRu(dppf) (Cp = η⁵-

C₅H₅and HMB = η⁶-C₆Me₆).^[3]A logical and interesting

follow-up of these studies on Ru would be a corresponding

reactivity study of the indenyl (Ind) analogue, as Ind can

potentially assume bonding modes involving η⁵-Cp or by

Scheme 1.

ring slippage to η³or η⁶-C₉H₇.^[4]Such an investigation is

also timely, as there is intense interest in reactivity aspects

of (Ind)Ru complexes, especially from catalytic perspec-

tives;^[5]and the bulk of the literature on (Ind)Ru complexes

deals with examples containing phosphanes as coligands,

with only two such complexes carrying S-donor ligands, viz.

SEt and SEtMe.^[6]Moreover, the outcome of the study will

provide a useful comparison to our completed study of

(Ind)Ru(dppf)Cl (1) with simple alkyl/aryl monothiolates,

SR^–(R = Me, Et, and Ph).^[7]This paper will describe the

results of reactions of 1, its dppm analogue 2, and (Ind)-

Ru(CO)₂I 18 with dialkyl dithiocarbamate, alkyl xanthate,

and bis(alkyl/aryl)dithiophosphinate, together with X-ray

[a] Department of Chemistry, National University of Singapore,

Kent Ridge, Singapore 117543, Singapore

Fax: +65-6779-1691

E-mail: chmgohly@nus.edu.sg

[b] Division of Chemistry and Biological Chemistry, Nanyang

Technological University,

Singapore 637616, Singapore

Supporting information for this article is available on the

WWW under http://ww w .eurjic.org or from the author.

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structural and electrochemical data of some of the new that the reaction mixture contained species 1 (δ =

complexes, and a computational estimation of the energies 51.7 ppm), 6 (δ = 62.8 ppm), 4 (δ = 47.1 ppm), and [(Ind)-

involved in η⁵Ǟ η³ring slippage of the indenyl ligand in Ru(η¹-dppf)(η²-S₂CNEt₂)] 4a (δ = –17.7 and 57.3), in an

selected molecules.

approximate 2:3:7:1 molar proportion after 4 h at room

temperature, but finally only complexes 4 and 6 in 3:2 molar

ratio after 16 h. A repeat of the reaction in CH₂Cl₂using 1

and NaS₂CNEt₂in 1:4 molar proportion yielded a final 1:1

molar mixture of 4 and 4a, which was isolated in 35% yield.

It was further demonstrated that the reaction of 4a with

NaS₂CNEt₂in MeOH yielded 4 (Scheme 3).

Results and Discussion

Reactions of [(Ind)Ru(L₂)Cl] (L₂= dppf, dppm)

Reaction with Dialkyl Dithiocarbamates

The structure of 4a was determined by X-ray diffraction

analysis. This is consistent with its NMR spectroscopic

data, which indicated the presence of η⁵-Ind and η²-

S₂CNEt₂ligands in the proton spectrum, and η¹-dppf in

the ³¹P spectrum (δ = –17.7 and 57.3, with the upfield signal

associated with the uncoordinated phosphorus atom).

The progression of 1 to 4 via 4a indicates the weaker

Complex [(Ind)Ru(dppf)Cl] (1) and its dppm analogue

[(Ind)Ru(dppm)Cl] (2) were reacted with NaS₂CNR₂. The

product mixture from the reaction of 1 in MeOH is both

stoichiometry- and time-dependent. Thus the addition of 1

mol-equiv. of ^–S₂CNR₂to 1 gives complexes [Ru(η²-

dppf)(η²-S₂CNR₂)₂] [R = Me (3), Et (4), C₅H₁₀(5)], to-

gether with the hydride, [(Ind)Ru(dppf)H] 6, which was not

–

observed with the use of excess S₂CNR₂(Scheme 2). The thermodynamic stability of bidentate dppf versus

release of indene in all cases is consistent with the formation ^–S₂CNEt₂, which in excess will also displace the indenyl li-

of the non-indenyl complexes 3–5. In the reaction of 1 with gand, accompanied by rechelation of the monodentate dppf

1 mol-equiv. of S₂CNEt₂, ³¹P NMR spectroscopy showed ligand in 4a to achieve the favored hexacoordination at

–

Scheme 2.

Scheme 3.

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Ru^II. We had previously isolated complex 4 in 80% yield by because of thermodynamic instability, though complexes

displacement of triphenylphosphane in Ru(η²-S₂CNEt₂)₂- with monodentate dppm are known.^[11]

(PPh₃)₂with dppf and have observed mono- and bidentate

exchange behavior of the dithiocarbamate ligand in solu- actions of LRu(dppf)Cl [L = Cp (A), HMB (B)] with

tion.^[8]

^–S₂CNEt₂were very different. For L = Cp, a dinuclear com-

Our previous studies showed that the outcome of the re-

The formation of 6 points to the role of methoxide plex [CpRu(S₂CNEt₂)₂]₂(µ-dppf) (C) was formed, and for L

arising from an equilibrium, as discussed before for SR^–= arene, ^–S₂CNEt₂displaced the arene ligand, as it dis-

(R = Me, Et):^[7]

placed the indenyl ligand in complex 1, as discussed above

(see Scheme 4, a,b^[3a]). In comparison, the analogous reac-

tion of [CpRu(dppe)Cl] (D) was reported to give the mono-

nuclear complex [CpRu(dppe)(η¹-S₂CNEt₂)] (E) (Scheme 4,

c).^[12]

It is significant that 6 was not detected when excess

^–S₂CNR₂was used. Although it is probable that it was

formed but underwent a facile H^–and S₂CNEt₂exchange,

–

as found in the reactions of CpRu(PPh₃)₂H with the halide

and SCN anions,^[9]this probability was ruled out experi-

mentally in this case, as 6 did not react at all with excess

Reaction with Alkyl Xanthates

The reaction of 1 with KS₂COR (R = Et, iPr) in MeOH

NaS₂CNR₂, indicating that 6 was not the intermediate lead- at room temp. or in refluxing CH₂Cl₂yielded [(Ind)Ru(η²-

ing to 4. As the formation of 4 requires 2 mole equiv. of dppf)(η¹-S₂COR)] in high yield [R = Et (9), 78% yield; R

^–S₂CNEt₂to 1, such a stoichiometric reaction was carried = iPr (10), 83% yield]. On the other hand, the reaction of 2

out in MeOH, in an attempt to further investigate the reac- with KS₂COiPr in MeOH gave only a non-indenyl complex

tion pathways. A yellow precipitate, identified as 4, was ob- [Ru(η²-dppm)(η²-S₂COiPr)₂] (11) (Scheme 5). There was no

tained, while the reaction of the filtrate with a new batch sign of the formation of any (Ind)Ru complex, neither

of 1 for 18 h at room temp. generated 6, indicative of the [(Ind)Ru(η²-dppm)(η¹-S₂COR)] nor [(Ind)Ru(η¹-dppm)(η²-

presence of ^–OMe in the filtrate. This indirectly demon- S₂COR)], indicative of thermodynamic instability of such

strated that MeOH was the proton source for the conver- indenyl compounds in MeOH. A change of solvent to

sion of the indenyl moiety to indene.

CH₂Cl₂was attempted; however, unlike in the case with

A comparative study was carried out on the reactivity of ^–S₂CNR₂, there was no reaction at all, even after prolonged

[(Ind)Ru(dppm)Cl] (2), the dppm analogue of 1, towards heating.

–

1

the nucleophile S₂CNR₂. As shown in Scheme 2, similar

The H NMR spectra of 9 and 10 showed the presence

observations were found in MeOH solvent, giving 7 (a com- of η⁵-Ind [δ(H²) 5.16–5.17, δ(H^1,3) 5.43–5.51]. Bidentate co-

pound similar to 4) and 8 (a hydride similar to 6);^[10]the ordination of dppf is evident from its single ³¹P resonance

latter was not formed when the nucleophile was used in in both 9 (δ = 54.9 ppm) and 10 (δ = 54.8 ppm). Mono-

excess. However, the dppm equivalent of 4a, that is, [(Ind)- dentate coordination of the xanthate ligand was supported

Ru(η¹-dppm)(η²-S₂CNEt₂)], was not observed, probably by X-ray diffraction analysis.

Scheme 4.^[3a]

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Scheme 5.

Scheme 6.

Complex 11 was formulated, based on its spectroscopic dithiophosphinate ligand at δ = 88.0–105.6, as well as for

1

data. Its H NMR spectrum showed the absence of a η⁵- dppm at δ = 4.0–5.1.

Ind ligand and its ³¹P NMR spectrum showed a singlet at

δ = 4.1, assignable to chelating dppm. The FAB⁺-mass spec-

trum showed the molecular ion peak at m/z 756, consistent

with the presence of the non-indenyl six-coordinate com-

plex.

Reactions of [(Ind)Ru(CO)₂I] (18) with NaS₂CNEt₂and

KS₂COiPr with or without Mediation by Trimethylamine

N-Oxide

The reaction of 18 with ^–S₂COiPr in MeOH gave, within

30 min, free indene and the six-coordinate Ru complex,

[Ru(η²-S₂COiPr)₂(CO)₂] (19) (Scheme 7). It is apparent that

Reaction with Dialkyl/Aryl Dithiophosphinates

The reactions of 1 with NaS₂PR₂gave high yields of

[(Ind)Ru(dppf)(η¹-S₂PR₂)] [R = Et (12), R = Ph (13)]

(Scheme 6). The similar reaction of the dppm complex 2

gave the dppm analogues of 12 and 13, viz. [(Ind)

Ru(dppm)(η¹-S₂PR₂)] [R = Et (14), 56%; and R = Ph (16),

50%], the lower yields probably arising from degradation

to the non-indenyl compounds, [Ru(dppm)(η²-S₂PR₂)₂] [R

= Et (15) and R = Ph (17)], which were isolated in 4–5%

yields.

–

the strong propensity of S₂COiPr towards chelation facili-

tated the dissociation of the weaker indenyl ligand rather

than the CO ligands. Liberation of free indene was likewise

observed in the reactions of 18 with thiolates, for example,

–

^–SMe or S₂CNC₆H₄.^[13]

1

The H NMR spectra of 12–14 and 16 showed η⁵-Ind

bonding to the Ru center, δ(H²) 4.84–5.15 and δ(H^1,3) 5.34–

6.12. In their ³¹P NMR spectra, the chelating diphosphanes

are seen as doublets (in the range δ = 53.1–54.8 for η²-dppf

in 12 and 13, and at δ = 12.5–12.6 for η²-dppm in 14 and

16), while the monodentate dithiophosphinate ligand is seen

as a triplet in the range δ = 84.9–87.9 for S₂PEt₂and δ =

70.9–71.1 for S₂PPh₂.

Scheme 7.

An attempt was made to hamper the dissociation of the

The multiplet nature of these resonances is indicative of indenyl ligand by generating a vacant site for coordination

coupling between the two ligands in each of these com- of the incoming bidentate thiolate. This was done by prior

plexes. However, for some unclear reason, such coupling is removal of CO ligands in 18 with trimethylamine N-oxide

not evident in the ³¹P NMR spectra of the non-indenyl dihydrate, TMNO·2H₂O. It was found that decarbonylation

complexes 15 and 17, both of which show a singlet for the of 18 resulted in a dark brown solution, from which a red

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(Indenyl)ruthenium Complexes Containing Dithiolate Ligands

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Scheme 8.

solid of [(Ind)Ru(CO)(µ-I)]₂(20) (70%) was obtained, un-

doubtedly from facile dimerization of the coordinatively un-

saturated [(Ind)Ru(CO)I] species.

1

Complex 20 was characterized, based on its H NMR

spectrum, which showed η⁵-Ind resonances at δ = 4.26

(H^1,3), 4.37 (H²), and 6.54–7.59 (H^5–8), its ESI⁺-mass spec-

trum, which gave the molecular ion peak at m/z 742.5 and

an isotopic fragmentation pattern indicative of a Ru₂moi-

ety, and its IR spectrum, which showed a terminal CO

stretch at 1925 cm^–1, in addition to an X-ray diffraction

analysis.

The dark brown solution of 20 in CH₃CN reacted slowly

with ^–S₂CNEt₂or ^–S₂COiPr giving dirty green and dirty

yellow solutions, respectively, from which (Ind)Ru(CO){η²-

(S–S)} [S–S = S₂CNEt₂(21, 55%), S₂COiPr (22, 81%)] was

isolated (Scheme 8).

Figure 1. ORTEP diagram of 4a. Thermal ellipsoids are drawn to

50% probability level. Hydrogen atoms are omitted for clarity. Se-

lected bond lengths [Å] and angles [°]: Ru1–C* 1.873, Ru1–C1

2.180(5), Ru1–C2 2.159(5), Ru1–C3 2.185(5), Ru1–C4 2.309(5),

Ru1–C9 2.302(5), Ru1–P1 2.2392(13), Ru1–S1 2.4068(13), Ru1–S2

2.3826(14), S1–C10 1.699(5), S2–C10 1.718(5), C10–N1 1.337(6),

P1–C21 1.825(5), P2–C26 1.810(6), S1–Ru1–S2 71.85(4), S1–Ru1–

P1 93.73(5), S2–Ru1–P1 88.04(5), S1–C10–S2 110.7(3), S1–C10–

N1 126.3(4), S2–C10–N1 122.9(4), C10–N1–C11 121.1(4), C10–

N1–C13 119.7(4), Ru1–P1–C21 111.90(16).

The infrared spectra of 21 and 22 in THF showed a new

CO stretching frequency at 2031 and 2041 cm^–1, respec-

tively. The presence of the η⁵-Ind ligand was again indicated

1

by the H NMR signals at δ = 4.77–4.85 (H²), 5.07–5.16

(H^1,3), and 6.83–7.16 (H^5–8). The molecular ions were ob-

served at m/z 393 and 380, respectively. The structure of

21 has been determined by single-crystal X-ray diffraction

analysis.

Table 1. Comparison of slip-fold parameters^[a]of the (η⁵-Ind)Ru

complexes.

Complex

∆ [Å]

HA [°]

FA [°]

[(Ind)Ru(DTC_Et)(η¹-dppf)] 4a

[(Ind)Ru(dppf)(η¹-S₂COEt)] 9

[(Ind)Ru(dppf)(η¹-S₂PEt₂)] 12

[(Ind)Ru(dppm)(η¹-S₂PPh₂)] 16

0.123

0.152

0.203

0.128

0.162,

0.185

0.165

4.68

6.23

7.52

6.38

6.32,

5.87

6.81

3.32

5.1

3.53

9.21

12.91

4.96

3.96,

4.18

4.83

5.59

8.4

Crystallographic Studies

The molecular structure of 4a is illustrated in the ORTEP [(Ind)Ru(CO)I]₂20

diagram (Figure 1, with selected bond parameters), which

[(Ind)Ru(CO)(DTC_Et)] 21

shows Ru coordinated to η⁵-Ind, η²-S₂CNEt₂, and η¹-dppf

ligands. The Cp rings of dppf are almost eclipsed (anticli-

nal) to each other, with a torsional angle (τ) of 136.58°.

The slip-fold parameters of the indenyl ligand (see Table 1)

suggest undistorted η⁵-coordination,^[14]with the benzenoid

ring “flipped” towards the Ru center, probably a conse-

quence of the relief in steric congestion around the metal

center, which undoubtedly is the underlying cause for the

dppf ligand to adopt a rare η¹-coordination mode, the first

such case (as far as we are aware) in a structurally charac-

terized mononuclear complex. Likewise steric demands

[(Ind)Ru(CO)I{P(CH₂Ph)₃}] F^[17]0.10

[(Ind)RuH(PPh₃)₂] G^[5a]

0.154

[a] ∆ is the difference in the average bond lengths of the metal to

the ring junction carbons, i.e., C4, C9, and of the metal to adjacent

carbon atoms of the five-membered ring, i.e., C1, C3. HA is the

angle between the planes defined by [C1,C2,C3] and

[C1,C3,C4,C9]. FA is the angle between the planes defined by

[C1,C2,C3] and [C4,C5,C6,C7,C8,C9]^[14](see Figure 9 for atom

numbering).

The asymmetric unit of complex 9 contains one ruthe-

have caused the pendant PPh₂group to point away from nium complex and two dichloromethane solvent molecules.

the [(Ind)Ru(S₂CNEt₂)] fragment. The extensive electron The Ru center is coordinated to η⁵-Ind, η²-dppf, and a

delocalization in the S₂CNEt₂ligand can be observed in the monodentate xanthate ligand. The Ru centers in 12 and 16

bond lengths of S1–C10, S2–C10, and C10–N1, the values are similarly coordinated with a monodentate dithiophos-

of which lie between those of a single and a double bond phinate ligand. The ORTEP diagrams of complexes 9, 12,

(C–S 1.81 Å; C=S 1.61 Å; C–N 1.47 Å; C=N 1.27 Å).^[15]

and 16 are shown in Figures 2, 3, and 4.

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Figure 2. ORTEP diagram of 9. Thermal ellipsoids are drawn to

50% probability level. Hydrogen atoms are omitted for clarity. Se-

lected bond lengths [Å] and angles [°]: Ru1–C* 1.918, Ru1–C1

2.220(3), Ru1–C2 2.186(3), Ru1–C3 2.212(3), Ru1–C4 2.361(3),

Ru1–C9 2.374(3), Ru1–P1 2.3110(7), Ru1–P2 2.2618(7), Ru1–S1

2.3964(7), S1–C10 1.712(3), S2–C10 1.674(3), C10–O1 1.331(4),

P1–Ru1–P2 97.43(3), S1–Ru1–P1 89.31(3), S2–Ru1–P2 86.53(3),

Ru1–S1–C10 116.03(10), S1–C10–S2 120.60(17), S1–C10–O1

116.4(2), S2–C10–O1 123.0(2), C10–O1–C11 118.5(2).

Figure 4. ORTEP diagram of 16. Thermal ellipsoids are drawn to

50% probability level. Hydrogen atoms are omitted for clarity. Se-

lected bond lengths [Å] and angles [°]: Ru1–C* 1.884, Ru1–C1

2.161(7), Ru1–C2 2.183(7), Ru1–C3 2.223(7), Ru1–C4 2.318(7),

Ru1–C9 2.321(7), Ru1–P1 2.2695(19), Ru1–P2 2.242(2), Ru1–S1

2.439(2), S1–P3 2.044(3), S2–P3 1.965(3), C10–P1 1.848(7), C10–

P2 1.848(8), P1–Ru1–P2 72.20(7), S1–Ru1–P1 84.98(7), S2–Ru1–P2

84.76(7), Ru1–S1–P3 117.45(10), S1–P3–S2 121.02(14), P1–C10–P2

92.0(3).

R groups in dithiophosphinate ligands and the indenyl li-

gands.

The six-coordinate complexes 7, 11, and 17 have also

been characterized by X-ray diffraction analysis. Their mo-

lecular structures were found to be similar to those of

known analogues, such as [Ru(dppf)(S₂CNEt₂)₂]^[8]and

[Ru(L)(LЈ)(S₂Z)₂] (L = CO, L = PEt₃, Z = CNMe₂, COEt,

L = LЈ = PMe₂Ph, Z = PEt₂)^[16](see electronic supporting

information).

The molecular structure of the di-iodo-bridged complex

20 is shown in the ORTEP diagram (Figure 5). The struc-

ture exhibits crystallographic mirror symmetry, with the

Figure 3. ORTEP diagram of 12. Thermal ellipsoids are drawn to

50% probability level. Hydrogen atoms and phenyl groups are

omitted for clarity. Selected bond lengths [Å] and angles [°]: Ru1–

C* 1.941, Ru1–C1 2.244(8), Ru1–C2 2.168(7), Ru1–C3 2.182(7),

Ru1–C4 2.408(7), Ru1–C9 2.424(8), Ru1–P1 2.2516(19), Ru1–P2

2.3181(18), Ru1–S1 2.4647(18), P1–Ru1–P2 98.98(7), S1–Ru1–P1

89.27(7), S1–Ru1–P2 86.07(6).

The η⁵-indenyl ligands in 9 and 16 do not show notice-

able distortion, while that of 12 is slightly distorted^[14](see

Table 1). The fold angle of complex 16 indicates that the

benzenoid ring of the indenyl ligand bends towards the ru-

thenium center rather than away as observed in 9 and 12.

This presumably is due to the coordination of a less steri-

cally demanding dppm compared to dppf. Another interest-

ing feature in the structures of complexes 9, 12, and 16 is

the orientation of the monodentate dithiolate ligand. The

noncoordinating S atom of the xanthate ligand in 9 is ori-

ented away from the indenyl ligand, whereas those of the

dithiophosphinate ligands in 12 and 16 are pointing

towards the indenyl ligands, as shown in their stereo views.

Figure 5. ORTEP drawing of [(Ind)Ru(CO)I]₂20 with 50% prob-

ability thermal ellipsoids. H atoms are omitted for clarity. Selected

bond lengths [Å] and angles [°]: Ru1–C* 1.874, Ru1–C12 2.142(16),

Ru1–C13 2.172(10), Ru1–C14 2.334(10), Ru2–C* 1.885, Ru2–C22

2.141(15), Ru2–C23 2.171(10), Ru2–C24 2.356(10), Ru1···Ru2

4.014, Ru1–I1 2.716(10), Ru2–I1 2.717(10), Ru1–C10 1.820(15),

Ru2–C20 1.812(16), I1–Ru1–I#1 84.37(4), I1–Ru2–I#1 84.35(4),

This probably arises from steric repulsion between the two C10–Ru1–I1 93.1(4), C20–Ru2–I1 92.5(4), Ru1–I1–Ru2 95.26(3).

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–

mirror plane passing through the two Ru centers, the two in S₂CNR₂possess the lowest electron density because of

CO ligands and the center of the two η⁵-Ind ligands extensive electron delocalization. Hence the increased ten-

through C12 and C22. As in [(Ind)Ru(CO)₂]₂, the structure dency of the latter towards chelation. In the absence of a

possesses two trans CO ligands and two trans [(Ind)- vacant site or an easily displaceable ligand, chelation of a

Ru(CO)] fragments, but unlike it, there is no interaction ligand will inevitably enforce dissociation of the indenyl li-

between Ru1 and Ru2 (4.014 Å).

gand. For rationalizing trend (ii), we note that the benze-

The ORTEP diagram for the molecular structure of 21 is noid ring of the indenyl ligand can be considered as an

depicted in Figure 6, together with selected bond param- electron-withdrawing group,^[18]hence an electron-rich Ru

eters. The structure shows a three-legged piano-stool con- center is required for strong interaction with η⁵-Ind through

figuration at Ru^II, being coordinated to η⁵-Ind, η²- its fused C₅H₃ring, a situation provided by strong donor

S₂CNEt₂, and one CO ligand. The slip-fold parameters for coligands like dppf, while labilization of the indenyl ligand

21 are in agreement with η⁵-coordination of Ind.^[14]As in will be assisted by the presence of a strong π-acceptor co-

the structure of 4a, the metric data show that there is exten- ligand, like CO.

sive electron delocalization in the S₂CNEt₂ligand.

The application of density functional theory has pro-

vided an understanding of the effect of different ligands on

the energetics of η⁵Ǟ η³ring slippage of the indenyl ligand

and hence on its dissociation tendency. In a recent study,

Veiros et al. demonstrated that the effect of the nature of

the coligands on the strength of the indenyl–metal bond

plays an important role in the energetics of η⁵versus η³

indenyl–molybdenum complexes.^[19]Because of the con-

straints on computational time, we have selected the com-

plexes [(Ind)Ru(L)₂(S₂COMe)] (H1: L = PMeH₂, H2: L =

PH₃, H3: L = CO), containing small phosphane ligands

such as PH₃and PH₂Me, rather than the larger diphos li-

gands (dppm or dppf), as the model compounds for study.

In this series, complex H1 contains the strongest σ-donor

ligand, followed by H2, with H3 possessing the strongest π-

acceptor ligand. The dissociation of the indenyl ligand by

η⁵Ǟ η³Ǟ η¹has been considered and the results are pre-

sented in Figure 7.

Figure 6. ORTEP drawing of (Ind)Ru(CO)(S₂CNEt₂) 21 with 50%

probability thermal ellipsoids. H atoms are omitted for clarity. Se-

lected bond lengths [Å] and angles [°]: Ru1–C* 1.910, Ru1–C1

2.210(4), Ru1–C2 2.174(4), Ru1–C3 2.191(4), Ru1–C4 2.358(4),

Ru1–C9 2.372(4), Ru1–S1 2.4035(10), Ru1–S2 2.3930(10), S1–C11

1.712(4), S2–C11 1.724(4), C11–N1 1.320(5), Ru1–C10 1.807(4),

S1–Ru1–S2 72.22(3), S1–C11–S2 110.7(2).

It was found that η⁵Ǟ η³indenyl ring slippage in com-

plexes H1 and H2 possesses comparable activation energy

(67 and 70 kJ/mol, respectively), with the process in H1 be-

ing slightly more endothermic (7.4 kJ/mol). However, a re-

markable difference was observed in the case of the strong

π-acceptor CO in complex H3. Not only is the activation

energy of the slippage almost half that for both H1 and

H2 (33 kJ/mol), but the η³-Ind coordination mode is more

favorable, with the η⁵Ǟ η³ring slippage process being exo-

thermic (–13 kJ/mol). This is consistent with the expecta-

tion that stronger σ-donor ligands enhance the interaction

between electron-rich Ru and the η⁵-Ind ligand and vice

versa. Therefore, as the dithiolate ligand tends to chelate to

the electron-deficient Ru, the weak interaction of the η⁵-

Ind ligand and the Ru center would have facilitated the ease

of η⁵Ǟ η³slippage, and the combined effect would be the

dissociation of the indenyl ligand.

An examination of slip-fold parameters of the indenyl

complexes in this study and two other reported examples

(Table 1) shows that complexes 4a, 16, 20, and 21 possess

FA values smaller than their HA values. This observation

is unusual for η⁵-indenyl complexes. The probable cause is

the lack of a bulky ligand directly below the benzenoid ring

of the Ind ligand in these complexes, unlike the structural

feature found in 9, 12, F, and G. In these four latter phos-

phane complexes, the steric repulsion between the indenyl

and bulky phosphane ligands forces the benzenoid ring to

“flip” away from the Ru center, hence resulting in greater

FA values.

Lability of the Indenyl Ligand

The foregoing results indicate that the lability of the in-

A comparison between the effect of xanthate and dithio-

denyl ligand is influenced by the incoming 1,1-dithiolate carbamate ligands on indenyl ring slippage has also been

and the coligands, according to the following trends: (i) di- made using the PH₃-containing complex H4 as the model

thiolates: ^–S₂CNR₂Ͼ ^–S₂COR Ͼ ^–S₂PR₂, (ii) coligands: CO compound. As shown in Figure 1, the formation of the η³-

≈ dppm Ͼ dppf. Trend (i) can be readily rationalized, based Ind isomer of the dithiocarbamate complex H4 is a much

on e-density considerations of the S donor atoms. The ob- more exothermic process. Unfortunately the transition state

servation of monodenticity of the S₂PR₂moiety in the high- for this process could not be located, though it is not un-

yield indenyl complexes, 12–14 and 16, is significant. In this common for activation energies of highly exothermic pro-

–

dithiolate series, the S atoms in S₂PR₂possess the most cesses to be much lower or even close to zero, thus causing

localized and hence highest electron density, whereas those the transition state to assume a structure similar to that of

Eur. J. Inorg. Chem. 2007, 3827–3840

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3833

L. Y. Goh et al.

FULL PAPER

Figure 7. Energy diagram of ring slippage from η⁵Ǟ η³(E^ais activation energy in kJ/mol).

the reactant. This may have caused difficulty in optimizing

the transition-state structure using computational methods.

Nevertheless the calculations indicated that ^–S₂CNR₂exerts

a stronger effect than xanthate in causing indenyl ring slipp-

age, in good agreement with the trend observed in the ex-

perimental data.

Electrochemical Studies

Cyclic voltammograms performed at a GC electrode in

0.5 m solutions of 10 and 13 in CH₂Cl₂at 233 K are

shown in Figure 8. Complex 10 displayed one chemically

irreversible oxidation process at about 0 V versus Fc/Fc⁺.

The expression “chemical reversibility” when used in con-

nection with cyclic voltammetry experiments relates to the

ratio of the oxidative (i_p^ox) to reductive peak currents (i_p^red).

The i_p^ox/i_pratio approaches unity for a fully chemically

red

Figure 8. Cyclic voltammograms performed at a 1-mm diameter

planar GC electrode in CH₂Cl₂(0.25  Bu₄NPF₆) at 233 K at a

scan rate of 100 mV/s for 0.5 m 10 and 13.

reversible process. Complex 13 showed three oxidation pro-

cesses, although the two most positive processes displayed

small reverse peaks when the scan direction was reversed,

suggesting instability of the highly oxidized states. Increas-

ing the scan rate up to 5 V/s did not improve the chemical

reversibility of the processes shown in Figure 8. Table 2 lists

the reversible oxidation potentials (E^r_1/2) that were calcu-

ox

red

where E_pand E_pare the anodic and cathodic peak po-

tentials respectively. In situations where small reverse peaks

were observed, only the forward (oxidative) peak potentials

are given.

red

lated from CV data under conditions where the i_p^ox/i_p

ratio was equal to unity and using the relationship [Equa-

tion (1)]

The peak current intensities were similar to those ob-

tained under identical conditions for the one-electron oxi-

(1) dation of 1, [(Ind)Ru(dppf)(SMe)], [(Ind)Ru(dppf)(SPh)],^[7]

E^r_1/2= (E_p+ E_p^red)/2

ox

3834

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Eur. J. Inorg. Chem. 2007, 3827–3840

(Indenyl)ruthenium Complexes Containing Dithiolate Ligands

FULL PAPER

Table 2. Cyclic voltammetric data obtained at a scan rate of ates, which results in ease of indenyl ligand dissociation at

100 mV/s at a 1-mm diameter glassy carbon electrode at 233 K in

CH₂Cl₂with 0.25  Bu₄NPF₆as the supporting electrolyte.

(Ind)Ru(dppf) as follows: dithiocarbamates Ͼ xanthates Ͼ

dithiophosphinates, in agreement with DFT calculations,

Compound

Oxidation process^[a]

and (iii) the solvent medium, as illustrated in complete

dissociation of Ind from (Ind)Ru(dppf) in dithiocarbamate

substitution in the highly polar solvent MeOH relative to

partial dissociation in CH₂Cl₂. In the case of the (Ind)-

Ru(CO)₂substrate, dissociation of Ind could be averted by

chemically assisted decarbonylation of the complex before

reaction with 1,1-dithiolate ligands. The hydride species

[(Ind)Ru(diphos)H], formed in solvent- and stoichiometry-

dependent yields in the (diphos) systems, presumably arose

from the presence of OMe^–in MeOH, as previously ob-

served.^[7]Cyclic voltammetry experiments indicate that the

(Ind)Ru(dppf) derivatives containing η¹-S₂COiPr and η¹-

S₂PPh₂can be oxidized in one-electron chemical irreversible

and reversible processes, respectively, at a scan rate of

100 mV/s at about 0 V versus Fc/Fc⁺.

ox

red

E_p[V]^[b]E_p[V]^[c]E^r_1/2[V]^[d]

∆E [mV]^[e]

10

13

–0.023

–0.004

+0.540

+0.830

–0.068

–0.04

64

[a] All potentials in Table 2 are relative to the ferrocene/ferrocenium

ox

red

redox couple. [b] E_pis the oxidative peak potential. [c] E_pis

the reductive peak potential. [d] E^r_1/2= (E_p+ E_p^ox)/2. [e] ∆E =

red

ox

|E_p– E_p^red|.

I, and [Cp*Ru(dppf)Cl] (VI), indicating that 10 and 13 were

also oxidized by one electron. However, 1, [(Ind)Ru(dppf)-

(SMe)], [(Ind)Ru(dppf)(SPh)], I, and VI showed two or

three one-electron chemically reversible oxidation processes,

whilst cyclic voltammograms performed on solutions of 10

and 13 indicated that their oxidized states were relatively

unstable even at low temperatures (Figure 8).^[7]

Experimental Section

General: All reactions were carried out using conventional Schlenk

techniques under inert nitrogen or under argon in an M. Braun

Labmaster 130 Inert Gas System. NMR spectra were measured

Based on previous studies, it is thought that the initial

oxidation process in Figure 8 for 10 and 13 is associated

with Ru^IIbeing oxidized to Ru^III(rather than oxidation in

the region of dppf), as this process is very sensitive to the

substituent (S or Ind) coordinated to the Ru. It is thought

that the second process in the CV of 13 is associated with

oxidation in the region of dppf, as the potential is close to

that observed in other dppf-containing complexes,^[7]while

the third oxidation process is associated with further oxi-

dation of the Ru ion. This would explain why the third oxi-

dation process shows more chemical reversibility than the

second process, if the individual regions (Ru and Fe) are

not electronically communicating, then it is possible that

the individual oxidation processes are semi-independent of

one another (i.e., the first and third are associated with oxi-

dation of the Ru ion, whilst the second process involves

oxidation in the vicinity of dppf).

Both compounds displayed one chemically irreversible

reduction process at very negative potentials (about –2.5 V

vs. Fc/Fc⁺), with a similar current magnitude to the first

oxidation process (indicating that the same number of elec-

trons were transferred). It is not possible to conclude

whether the chemical instability of the reduced compounds

is because of increased chemical reactivity due to the very

high reduction potentials, or due to an η⁵Ǟ η³ring slipp-

age mechanism following reduction.

1

on a Bruker 300 FT NMR spectrometer, H chemical shifts were

referenced to residual solvent in the deuterio-solvents, C₆D₆or

CD₃CN, and ³¹P chemical shifts were referenced to external

H₃PO₄. IR spectra in KBr pellets were measured in the range 4000–

400 cm^–1by means of a BioRad FTS-165 FTIR instrument. Mass

spectra were run on a Finnigan Mat 95XL-T (FAB) or a Finnigan-

MAT LCQ (ESI) spectrometer. Voltammetric experiments were

conducted with a computer-controlled Eco Chemie µAutolab III

potentiostat. The electrochemical cell was jacketed in a glass sleeve

and cooled to 233 K using a Lauda RL6 variable-temperature

methanol-circulating bath. Elemental analyses were performed by

the microanalytical laboratory in-house. [(Ind)Ru(dppf)Cl] (1),^[20]

[(Ind)Ru(dppm)Cl] (2),^[21]and [(Ind)Ru(CO)₂I] (18)^[22]were pre-

pared by published methods. All other chemicals were obtained

commercially and used without any further purification. All sol-

vents were dried with sodium/benzophenone and distilled before

use. Celite (Fluka AG) and silica gel (Merck Kieselgel 60, 230–400

Mesh) were dried at 140 °C overnight before chromatographic use.

Conventional numbering of indenyl protons shown in Figure 9 is

followed in the assignment of NMR signals.

Figure 9. Atom labeling of the indenyl ligand.

Conclusions

(I) Reactions of (Ind)Ru(diphosphane) Complexes

(a) Reactions with Dialkyl Dithiocarbamates

The lability of the Ind ligand in halide substitution of

[(Ind)Ru(L₂)Cl] [L₂= dppf, dppm or (CO)₂] with 1,1Ј-di-

thiolates is dependent on several variables: (i) the nature of

the coligand L₂, which follows a lability order: dppf Ͻ

dppm ≈ CO, in agreement with the electron donor capa-

bility of L₂and calculated energetics for η⁵Ǟ η³ring slipp-

(i) Reactions of [(Ind)Ru(dppf)Cl] (1) with NaS₂CNR₂were carried

out at stoichiometries of 1:1 and 1:4. A typical reaction for each

stoichiometry is described for R = Et, as follows:

1:S₂CNR₂(1:1): NaS₂CNEt₂·3H₂O (10 mg, 0.04 mmol) was added

to a suspension of 1 (35 mg, 0.04 mmol) in MeOH (5 mL) and the

age in related (Ind)Ru complexes, (ii) the incoming dithiol- mixture was stirred at room temp. for 18 h. The color of the suspen-

Eur. J. Inorg. Chem. 2007, 3827–3840

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3835

L. Y. Goh et al.

FULL PAPER

sion slowly changed from red to yellow. The suspension was filtered

and the residue was extracted using toluene (2ϫ5 mL). The filtrate

was examined by GC/MS, which showed indene. The extract was

concentrated to about 2 mL and loaded onto a silica gel column

(2ϫ5 cm) prepared in n-hexane. Elution gave two fractions: (i) a

yellow eluate in toluene (8 mL), which yielded [(Ind)Ru(dppf)H] (6)

(13 mg, 39% yield) (for the reaction in which R = Me, 11 mg, 32%

yield, R = C₅H₁₀, 8 mg, 25% yield), (ii) a yellow eluate in toluene/

THF (1:1, 10 mL), which yielded [Ru(η²-dppf)(η²-S₂CNEt₂)₂] 4

(25 mg, 60% yield). Similar reactions gave 3 (R = Me), 22 mg, 56%

yield, and 5 (R = C₅H₁₀), 25 mg, 58% yield. Analytical pure sam-

ples of complexes 3–5 were obtained by recrystallization from

THF/hexane (1:5).

[M – Ind]⁺. C₄₈H₄₅FeNP₂RuS₂(918.87): calcd. C 62.7, H 4.9, N

1.5, S 7.0, found C 62.6, H 5.2, N 1.3, S 6.9.

1

Data for 5: H NMR (C₆D₆): δ = 0.95 (br. s, 12 H, S₂CNC₅H₁₀),

3.02, 3.63 (each br. s, 4 H, S₂CNC₅H₁₀), 3.95, 4.05, 4.62 and 4.71

(each s, 2 H, C₅H₄), 7.00–7.23, 7.69–7.72, 8.03–8.05 and 8.19–8.24

(each m, total 20 H, Ph) ppm. ³¹P{¹H} NMR (C₆D₆): δ = 47.6 (s,

dppf) ppm. IR (KBr): ν = 3048 (w), 2931 (m), 2853 (m), 1479 [s,

˜

SC(S)], 1433 [s, SC(S)], 1233 [s, SC(S)], 1129 (m), 1086 (m), 995

(m), 885 (w), 850 (w), 811 (w), 743 (m), 695 (s), 546 (m), 518 (m)

cm^–1. FAB⁺-MS: m/z (%) = 976 [M]⁺, 816 [M – S₂CNC₅H₁₀]⁺.

C₄₆H₄₈FeN₂P₂RuS₄(976.01): calcd. C 56.6, H 5.0, N 2.9, S 13.1,

found C 56.5, H 5.0, N 2.7, S 12.9.

(ii) Reactions of [(Ind)Ru(dppm)Cl] 2 with NaS₂CNEt₂were car-

1:S₂CNR₂(1:4). Reaction in MeOH: NaS₂CNEt₂·3H₂O (40 mg,

0.16 mmol) was added to a suspension of 1 (35 mg, 0.04 mmol) in

MeOH (5 mL) and the mixture was stirred at room temp. for 18 h.

The color of the suspension slowly changed from red to yellow.

The solvent was removed in vacuo and the residue was extracted

with toluene (2ϫ5 mL). The extract was concentrated to about

2 mL, addition of hexane (2 mL) at –30 °C for 1 d gave yellow crys-

tals of 4 (37 mg, 90% yield). Similar reactions gave 3 (R = Me),

36 mg, 92% yield, and 5 (R = C₅H₁₀), 41 mg, 98% yield.

ried out at stoichiometries of 1:1 and 1:4.

2:S₂CNR₂(1:1): NaS₂CNEt_2t·3H₂O (10 mg, 0.04 mmol) was

treated with 2 (20 mg, 0.04 mmol) in MeOH (5 mL). A similar

workup as described above for the dppf analogue yielded

[Ru(dppm)(η²-S₂CNEt₂)₂] (7) (18 mg, 58% yield) and [(Ind)

Ru(dppm)H] (8) (5 mg, 20% yield), identified by its published pro-

ton NMR spectroscopic data, notably δ(H) –14.21 (s) in C₆D₆ver-

sus the lit. value of –14.12 (s) in CD₂Cl₂.^[10]

Using 2:S₂CNR₂(1:4): A similar reaction as described above for 1

was carried out, using NaS₂CNEt₂·3H₂O (20 mg, 0.08 mmol) and

[(Ind)Ru(dppm)Cl] (2) (10 mg, 0.02 mmol) in MeOH (5 mL) and

the mixture was stirred for 4 h. Similar workup procedures gave

yellow crystals of [Ru(dppm)(η²-S₂CNEt₂)₂] (7) (10 mg, 81% yield).

Reaction in CH₂Cl₂: NaS₂CNEt₂·3H₂O (60 mg, 0.24 mmol) was

added to a solution of 1 (50 mg, 0.06 mmol) in CH₂Cl₂(10 mL)

and the mixture was refluxed for 4 h. The solution was evacuated

to dryness and the residue extracted with diethyl ether (2ϫ3 mL).

The extract was concentrated to about 3 mL and kept at –30 °C,

after 2 d, yellow microcrystals of 4 (16 mg, 28% yield) were col-

lected. Addition of hexane (about 0.5 mL) to the mother liquor

led to the isolation of red microcrystals of [(Ind)Ru(η¹-dppf)(η²-

S₂CNEt₂)] (4a) (20 mg, 36% yield) after two more days at –30 °C.

1

Data for 7: H NMR (C₆D₆): δ = 0.63–0.68 and 0.86–0.91 (each t-

like m, 6 H, CH₃), 2.85–3.02 (m, 2 H, CH₂CH₃), 3.15–3.28 (m, 2

H, CH₂CH₃), 3.43–3.62 (m, 4 H, CH₂CH₃), 4.73 (t, ²J_HP= 9.9 Hz,

2 H, CH₂of d), 6.98–7.16 (m, 14 H, Ph), 7.54–7.58 (m, 3 H, Ph),

7.93–7.95 (m, 3 H, Ph) ppm. ³¹P{¹H} NMR (C₆D₆): δ = 3.7 (s,

A small-scale reaction was carried out at stoichiometry 1:2, using 1

(5 mg, 6.2 µmol) and NaS₂CNEt₂·3H₂O (3 mg, 12 µmol) in MeOH

(2 mL) and the red suspension was stirred at room temp. for 18 h.

The resultant yellow suspension was filtered to give yellow solids,

4 (5 mg, 85% yield), and pale yellow filtrate. The ¹H and ³¹P NMR

spectra of the yellow solids (in C₆D₆) showed 4 as the sole product.

A new batch of 1 (5 mg, 6.2 µmol) was added to the filtrate and the

red suspension was stirred for another 18 h. The resultant yellow

suspension was filtered and the yellow solids, 6 (4 mg, 84% yield)

dppm) ppm. IR (KBr): ν = 3050 (w), 2974 (w), 2929 (w), 2871 (w),

˜

1483 [s, SC(S)], 1426 [s, SC(S)], 1303 (w), 1268 [s, SC(S)], 1214 (m),

1142 (m), 1091 (m), 997 (w), 911 (w), 848 (w), 698 (s), 535 (m)

cm^–1. FAB⁺-MS: m/z (%) 782 [M]⁺, 634 [M – S₂CNEt₂]⁺.

C₃₅H₄₂N₂P₂RuS₄(782.00): calcd. C 53.8, H 5.4, N 3.6, S 16.4,

found C 53.8, H 5.5, N 3.7, S 16.2.

(b) Reactions with Alkyl Xanthates

1

were obtained. The H and ³¹P NMR spectra of the yellow solids

(i) KS₂COR (0.07 mmol, R = Et, 11 mg, R = iPr, 12 mg) was added

into a solution of 1 (15 mg, 0.02 mmol) in CH₂Cl₂(10 mL) and the

mixture was refluxed. The reaction was not accompanied by any

in C₆D₆indicate the sole presence of 6.

Data for 3: ¹H NMR (C₆D₆): δ = 2.41 and 2.43 [each s, 3 H,

S₂CN(CH₃)₂], 3.94, 4.04, 4.62 and 4.69 (each s, 2 H, C₅H₄), 7.03–

7.11, 7.21–7.25, 7.95 and 8.20–8.25 (m, 20 H, Ph) ppm. ³¹P{¹H}

1

color change, hence it was monitored by H and ³¹P NMR spec-

troscopy. After the reaction was complete (about 4 h), the solution

was evacuated to dryness. The solid residue was extracted with tol-

uene (2ϫ2 mL) and the concentrated extract recrystallized from

1:2 THF/hexane at –30 °C. Red microcrystals of [(Ind)Ru(dppf)(η¹-

S₂COR)] [R = Et (9), 13 mg, 78% yield, R = iPr (10), 14 mg, 83%

yield] were obtained after one day.

NMR (C D ): δ = 47.9 (s, dppf) ppm. IR (KBr): ν = 3053 (w),

˜

6

2922 (w), 2855 (w), 1509 [m, SC(S)], 1432 [m, SC(S)], 1386 [s,

SC(S)], 1262 [m, SC(S)], 1146 (m), 1086 (m), 1028 (m), 811 (w),

746 (w), 697 (m), 548 (w), 521 (w) cm^–1. FAB⁺-MS: m/z (%) = 896

[M]⁺, 776 [M

–

S₂CNMe₂]⁺. C₄₀H₄₀FeN₂P₂RuS₄·1/4C₆H₁₂

3

Data for 9: ¹H NMR (C₆D₆): δ = 1.06 (t, J_HH= 7.4 Hz, 3 H,

(917.39): calcd. C 54.3, H 4.7, N 3.1, S 14.0, found C 54.1, H 5.1,

N 3.2, S 13.5.

S₂COCH₂CH₃), 3.55, 3.81, 3.98 and 4.34 (each s, 2 H, C₅H₄), 4.41

3

(q, J_HH= 7.4 Hz, 2 H, S₂COCH₂CH₃), 5.16 (s, 1 H, H²), 5.43 (s,

3

Data for 4a: ¹H NMR (C₆D₆): δ = 0.61 [t, J_HH= 7.4 Hz, 6 H,

2 H, H^1,3), 6.98–7.14, 7.26–7.30 and 7.43–7.48 (each m, total 24 H,

3

S₂CN(CH₂CH₃)₂], 2.81 and 3.04 [each m, J_HH= 7.4 Hz, 2 H,

H^5–8and Ph) ppm. ³¹P{¹H} NMR (C₆D₆): δ = 54.9 (s, dppf) ppm.

S₂CN(CH₂CH₃)₂], 4.11 and 4.33 (each s, 2 H, C₅H₄), 4.19 (s, 4 H,

IR (KBr): ν = 3050 (w), 2978 (w), 1478 (w), 1432 (w), 1382 (w),

˜

3

C₅H₄), 4.56 (t, J_HH= 2.5 Hz, 1 H, H²), 4.89 (d, J_HH= 2.5 Hz, 2

H, H^1,3), 7.04–7.16, 7.37–7.40, 7.42–7.48 and 7.75–7.81 (each m,

total 24 H, H^5–8and Ph) ppm. ³¹P{¹H} NMR (C₆D₆): δ = 57.3

1165 [s, (CO)], 1105 [s, (CS)], 1030 [vs, (CS)], 858 w, 819 w, 792 w,

744 m, 697 s, 631 w, 513 m. FAB⁺-MS: m/z (%) = 892 [M]⁺, 777

[M – Ind]⁺, 655 [M – Ind – S₂COEt]⁺. C₄₆H₄₀FeOP₂RuS₂(891.80):

calcd. C 62.0, H 4.5, S 7.2, found C 61.6, H 4.8, S 7.5.

and –17.7 (each s, dppf) ppm. IR (KBr): ν = 3050 (w), 2972 (w),

˜

2929 (w), 1484 [s, SC(S)], 1431 [vs, SC(S)], 1380 (w), 1324 (w), 1270

1

3

[m, SC(S)], 1215 (w), 1159 (m), 1092 (m), 1030 (m), 830 (w), 743 Data for 10: H NMR (C₆D₆): δ = 1.25 [d, J_HH= 5.76 Hz, 6 H,

(m), 696 (vs), 543 (m), 517 (m) cm^–1. FAB⁺-MS: m/z (%) = 804

S₂COCH(CH₃)₂], 3.55, 3.84, 3.98 and 4.46 (each s, 2 H, C₅H₄),

3836

www.eurjic.org

Eur. J. Inorg. Chem. 2007, 3827–3840

(Indenyl)ruthenium Complexes Containing Dithiolate Ligands

FULL PAPER

5.17 (s, 1 H, H²), 5.51 (s, 2 H, H^1,3), 5.67 [sept, J = 6.6 Hz, 1 H, red mixture was stirred at room temp. for 18 h. The red product

S₂COCH(CH₃)₂] 7.00–7.47 (m, 24 H, H^5–8and Ph) ppm. ³¹P{¹H} solution was evacuated to dryness and the residue extracted with

NMR (C D ): δ = 54.8 (s, dppf) ppm. IR (KBr): ν = 3047 (w),

toluene (2ϫ3 mL). The extract was concentrated to about 2 mL

and loaded on a silica gel column (1.5ϫ2.0 cm). Elution gave three

fractions: (i) a yellow eluate in ether/hexane (1:2, about 4 mL),

which yielded [Ru(dppm)(η¹-S₂PR₂)₂] (R = Et (15), 3 mg, 5% yield,

R = Ph (17), 3 mg, 4% yield), (ii) a red eluate in ether:hexane (2:1,

4–8 mL), which yielded [(Ind)Ru(dppm)(η¹-S₂PR₂)] (R = Et (14),

16 mg, 56% yield, R = Ph (16), 33 mg, 50% yield), (iii) an orange-

yellow eluate in THF (3 mL), which gave 2 in trace amounts.

˜

6

2963 (w), 2923 (w), 1940 (w), 1478 (w), 1433 (w), 1382 (w), 1261

[m, (CO)], 1187 (w), 1089 [s, SC(S)], 1015 [s, SC(S)], 803 (s), 743

(m), 695 (s), 631 (w), 507 (m) cm^–1. FAB⁺-MS: m/z (%) = 906

[M]⁺, 791 [M – Ind]⁺, 771 [M – S₂COiPr]⁺, 655 [M – Ind – S₂CO-

iPr]⁺. C₄₇H₄₂FeOP₂RuS₂(905.83): calcd. C 62.3, H 4.7, S 7.0,

found C 61.9, H 4.8, S 6.6.

(ii) KS₂COiPr (23 mg, 0.13 mmol) was added to a solution of 2

(20 mg, 0.03 mmol) in MeOH (5 mL) and the solution was stirred

at room temp. for 18 h. The color of the solution changed slowly

from red to yellow in the course of reaction. The yellow product

solution was evacuated to dryness and the residue extracted with

toluene (2ϫ2 mL). Addition of hexane (about 4 mL) into the con-

centrated extract (about 2 mL) at –30 °C for 1 d gave

[Ru(dppm)(η²-S₂COiPr)₂] (11) (27 mg, 93% yield) as yellow micro-

crystals.

1

3

Data for 14: H NMR (C₆D₆): δ = 1.07 and 1.11 [each t, J_HH

=

7.4 Hz, 3 H, S₂P(CH₂CH₃)₂], 1.46–1.57 [m, 4 H, S₂P(CH₂CH₃)₂],

3

4.04–4.16 and 4.43–4.54 [each m, 1 H, CH₂(PPh₂)₂], 5.15 (t, J_HH

3

= 2.5 Hz, 1 H, H²), 6.12 (d, J_HH= 2.5 Hz, 2 H, H^1,3), 6.89–7.12,

7.23–7.29, 7.37–7.43 and 7.78–7.81 (each m, total 24 H, H^5–8and

3

Ph) ppm. ³¹P{¹H} NMR (C₆D₆): δ = 12.5 (d, J_PP= 19 Hz, d),

3

84.9 (t, J_PP= 19 Hz, S PEt ) ppm. IR (KBr): ν = 3052 (w), 2967

˜

2

(w), 2927 (w), 1433 (m), 1324 (w), 1093 (m), 1027 (w), 730 [s, (PS)],

697 [vs, (PS)], 596 (m, (PS)], 534 m, 510 m. FAB⁺-MS: m/z (%) =

791 [M – Ind + S₂PEt₂]⁺, 639 [M – Ind]⁺, 601 [M – S₂PEt₂]⁺.

C₃₈H₃₉P₃RuS₂(753.84): calcd. C 60.5, H 5.2, S 8.5, found C 60.6,

H 5.3, S 8.3.

1

Data for 11: H NMR (C₆D₆): δ = 0.87–0.89 and 0.95–0.97 (each

2

d-like m, 6 H, CH₃), 4.67 (t, J_HP= 9.9 Hz, 2 H, CH₂of d), 5.34

3

[sept, J_HH= 6.6 Hz, 2 H, CH(CH₃)₂], 6.95–7.02 (m, 7 H, Ph),

7.08–7.16 (m, 5 H, Ph), 7.38–7.45 (m, 4 H, Ph), 7.81–7.89 (m, 4 H,

Ph) ppm. ³¹P{¹H} NMR (C₆D₆): δ = 4.1 (s, dppm) ppm. IR (KBr):

Data for 15: ¹H NMR (C₆D₆):

δ = 0.45–0.57 [m, 6 H,

ν = 3049 (w), 2976 (w), 2930 (w), 1481 (w), 1432 (m), 1371 (w),

˜

S₂P(CH₂CH₃)₂], 0.87–1.02 [m, 4 H, S₂P(CH₂CH₃)₂], 1.14–1.25 [m,

6 H, S₂P(CH₂CH₃)₂], 2.18–2.45 [m, 4 H, S₂P(CH₂CH₃)₂], 4.78–4.85

[m, 2 H, CH₂(PPh₂)₂], 6.91–7.34 and 8.10–8.16 (each m, total 20

H, Ph) ppm. ³¹P{¹H} NMR (C₆D₆): δ = 5.1 (s, d), 105.6 (s, S₂PEt₂)

1231 [vs, (CO)], 1093 [vs, SC(S)], 1033 [s, SC(S)], 905 m, 723 s, 696

s, 538 m, 509 s. FAB⁺-MS: m/z (%) = 756 [M]⁺. C₃₃H₃₆O₂P₂RuS₄

(755.92): calcd. C 52.4, H 4.8, S 17.0, found C 52.4, H 4.8, S 17.0.

(c) Reactions with Dithiophosphinates

ppm. IR (KBr): ν = 3049 (w), 2967 (w), 2929 (w), 2874 (w), 1433

˜

(m), 1096 (m), 1036 (w), 723 [s, (PS)], 699 [vs, (PS)], 674, 603 [w,

(PS)], 541 (m), 510 (m) cm^–1. FAB⁺-MS: m/z (%) = 791 [M]⁺, 639

[M – S₂PEt₂]⁺. C₃₃H₄₂P₄RuS₄(791.92): calcd. C 50.0, H 5.4, S 16.2,

found C 50.2, H 5.4, S 15.7.

(i) NaS₂PR₂(0.04 mmol, R = Et, 7 mg, R = Ph, 11 mg) was added

to a suspension of 1 (10 mg, 0.01 mmol) in MeOH and the mixture

was stirred at room temp. for 18 h. The resultant red solution was

evacuated to dryness and the residue extracted with toluene

(2ϫ3 mL). The extract was concentrated to about 2 mL and

loaded on a silica gel column (1.5ϫ2.0 cm). Elution with 2:1 hex-

ane/diethyl ether (3–5 mL) and subsequent workup gave red crys-

tals of [(Ind)Ru(dppf)(η¹-S₂PR₂)] (R = Et (12), 8 mg, 70% yield,

R = Ph (13), 9 mg, 72% yield).

1

Data for 16: H NMR (C₆D₆): δ = 3.94–4.06 and 4.42–4.54 [each

3

m, 1 H, CH₂(PPh₂)₂], 5.15 (t, J_HH= 2.5 Hz, 1 H, H²), 5.82 (d,

³J_HH= 2.5 Hz, 2 H, H^1,3), 6.66–6.69 (4-line m, 2 H, H^4–7), 6.90–

7.11, 7.26–7.32, 7.47–7.53 and 8.13–8.20 [each m, total 32 H,

S₂PPh_2,CH₂(PPh₂)₂, 2H of H^5–8] ppm. ³¹P{¹H} NMR (C₆D₆): δ =

3

Data for 12: ¹H NMR (C₆D₆):

δ = 1.18–1.30 [m, 6 H,

12.6 (d, J_PP= 15 Hz, d), 70.9 (t, J_PP= 19 Hz, S₂PPh₂) ppm. IR

(KBr): ν = 3050 (w), 1481 (w), 1434 (s), 1306 (w), 1098 (s), 726 [m,

˜

S₂P(CH₂CH₃)₂], 1.90–2.12 [m, 4 H, S₂P(CH₂CH₃)₂], 3.70, 3.81,

(PS)], 703 [vs, (PS)], 568 [s, (PS)], 539 (m), 509 (m) cm^–1. FAB⁺-

MS: m/z (%) 850 [M]⁺, 735 [M – Ind]⁺, 601 [M – S₂PPh₂]⁺.

C₄₆H₃₉P₃RuS₂(849.93): calcd. C 65.0, H 4.6, S 7.6, found C 65.2,

H 5.0, S 7.7.

4.20 and 5.15 (each s, 2 H, C₅H₄), 4.84 (s, 1 H, H²), 5.70 (s, 2 H,

3

H^1,3), 6.90–6.93 and 7.58–7.61 (each 4-line m, J_HH= 3.3 Hz, 2 H,

H^5–8), 7.11–7.68 (m, 20 H, Ph) ppm. ³¹P{¹H} NMR (C₆D₆): δ =

3

54.8 (d, J_PP= 16 Hz, dppf), 87.5 (t, J_PP= 16 Hz, S₂PEt₂) ppm.

IR (KBr): ν = 3054 (w), 2966 (w), 2924 (w), 2868 (w), 1479 (w),

Data for 17: ¹H NMR (C₆D₆): δ = 4.76–4.82 [m, 2 H, CH₂-

(PPh₂)₂], 6.91–7.34, 8.08–8.26 (each m, total 40 H, Ph) ppm.

³¹P{¹H} NMR (C₆D₆): δ = 4.0 (s, d), 88.0 (s, S₂PPh₂) ppm. IR

˜

1433 (m), 1325 (w), 1157 (w), 1090 (m), 1030 (m), 821 (m), 746 [s,

(PS)], 695 (PS), 594 [w, (PS)], 632 (m), 511 (s) cm^–1. FAB⁺-MS: m/z

(%) = 924 [M]⁺, 809 [M – Ind]⁺, 771 [M – S₂PEt₂]⁺, 655 [M – Ind –

S₂PEt₂]⁺. C₄₇H₄₅FeP₃RuS₂(923.833): calcd. C 61.1, H 4.9, found

C 61.4, H 4.7.

(KBr): ν = 3049 (w), 2923 (w), 2854 (w), 1480 (w), 1433 (m), 1305

˜

(w), 1097 (s), 1025 (w), 997 (w), 845 (w), 725 [s, (PS)], 703 [vs, (PS)],

631 (w), 608 (w), 567 [s, (PS)], 538 (m), 508 (m) cm^–1. FAB⁺-MS:

m/z (%) 984 [M]⁺, 735 [M – S₂PPh₂]⁺. C₄₉H₄₂P₄RuS₄(984.09):

calcd. C 59.8, H 4.3, S 13.0, found C 60.1, H 4.6, S 12.6.

1

Data for 13: H NMR (C₆D₆): δ = 3.60, 3.79, 4.05 and 5.20 (each

s, 2 H, C₅H₄), 5.10 (s, 1 H, H²), 5.34 (s, 2 H, H^1,3), 6.61–6.64 and

7.35–7.39 (each 4-line m, 2 H, H^5–8), 7.05–7.19, 7.26–7.33 and 7.45–

7.51 (each m, total 26 H, Ph), 8.43–8.50 (4-line m, 4 H, Ph) ppm.

(II) Reactions of (Ind)Ru(carbonyl) Complexes

3

³¹P{¹H} NMR (C₆D₆): δ = 53.1 (d, J_PP= 15 Hz, dppf), 71.1 (t,

(a) Reaction with Isopropyl Xanthate: A solution of [(Ind)Ru-

(CO)₂I] (18) (50 mg, 0.13 mmol) and KS₂COiPr (45 mg,

0.26 mmol) in CH₃OH (15 mL) was stirred for 30 min at ambient

temperature. The red solution slowly turned orange-yellow. Solvent

was removed under vacuo and extracted with toluene (about

20 mL) to afford orange-red solids of [Ru(CO)₂(η²-S₂COiPr)₂] (19)

(24 mg, 50% yield).

³J_PP= 15 Hz, S PPh ) ppm. IR (KBr): ν = 3052 (w), 2922 (w),

˜

2

2854 (w), 1650 (w), 1477 (w), 1433 (m), 1158 (w), 1089 (m), 1033

(w), 821 (w), 745 [m, (PS)], 698 [s, (PS)], 649 [m, (PS)], 512 (m)

cm^–1. FAB⁺-MS: m/z (%) = 1020 [M]⁺, 905 [M – Ind]⁺, 771 [M –

S₂PPh₂]⁺, 655 [M – Ind – S₂PPh₂]⁺. C₅₅H₄₅FeP₃RuS₂(1019.91):

calcd. C 64.8, H 4.5, S 6.3, found C 64.8, H 4.4, S 5.8.

1

(ii) NaS₂PR₂(0.31 mmol, R = Et, 55 mg, R = Ph, 85 mg) was

added to a suspension of 2 (50 mg, 0.08 mmol) in MeOH and the

Data for 19: H NMR (C₆D₆): δ = 0.85 (m, 6 H, CH₃), 5.15 (sept,

³J_HH= 6.1 Hz, 1 H, CH) ppm. ¹³C NMR (C₆D₆): δ = 21.8 (CH₃),

Eur. J. Inorg. Chem. 2007, 3827–3840

www.eurjic.org

3837

L. Y. Goh et al.

FULL PAPER

78.0 (O-CH), 195.3 (SCO), 230.0 (CO) ppm. IR (THF): ν_CO= 2047

351.9524 (calcd.). C₁₄H₁₄O₂RuS₂(379.46): calcd. C 44.3, H 3.7, S

16.9, found C 44.7, H 3.7, S 16.8.

˜

s, 1986 (s) cm^–1(literature^[23]values 2052 s, 1990 s in C₆H₁₂). FAB⁺-

MS: 429.3 [M + H]⁺.

Crystal Structure Determinations: X-ray diffraction-quality crystals

were obtained at –30 °C from solvent mixtures as follows: 7, 9, 11,

16, and 17 from CH₂Cl₂/hexane, 4a from CH₂Cl₂/ether and 12 from

THF/hexane, while those of 20 and 21 were obtained at room tem-

perature from C₆D₆and CH₃CN/C₆D₆, respectively. Crystals were

mounted on quartz fibers. X-ray data were collected on a Bruker

AXS APEX system, using Mo-K_αradiation, with the SMART suite

of programs.^[24]Data were processed and corrected for Lorentz and

polarization effects with SAINT,^[25]and for absorption effects with

SADABS.^[26]Structural solution and refinement were carried out

with the SHELXTL suite of programs.^[27]Crystal and structure

refinement data are summarized in Table 3. The structures were

solved by direct methods or Patterson maps to locate the heavy

atoms, followed by difference maps for the light, non-hydrogen

atoms. All non-hydrogen atoms were generally given anisotropic

displacement parameters in the final model.

(b) Reaction with Trimethylamine N-Oxide (TMNO): A solution of

18 (20.0 mg, 0.05 mmol) and TMNO·2H₂O (12.0 mg, 0.11 mmol)

in CH₃CN (10 mL) was stirred for 1 h at ambient temperature. The

resulting dark brown solution was adsorbed onto Celite (150 mg).

Solvent was removed under vacuo and the Celite mixture was

loaded onto a silica gel column (5ϫcm) prepared in n-hexane. Elu-

tion with toluene gave an orange-red solution (about 40 mL),

which, upon removal of solvent to dryness, afforded a red solid of

[(Ind)Ru(CO)I]₂(20) (13 mg, 70% yield).

In a repeated reaction of the same scale, the resulting brown solu-

tion was evacuated to dryness. The residue was dissolved in C₆D₆

and filtered. The reddish brown filtrate was allowed to evaporate

at room temperature. Analytical pure red microcrystals of 20 were

obtained after 2 d (10 mg, 54% yield).

3

Data for 20: ¹H NMR (C₆D₆): δ = 4.26 (d, J_HH= 2.5 Hz, 4 H,

3

The crystal of 4a contains one and a half Et₂O solvent molecules.

The half solvent molecule was disordered over two sites related by

an inversion center, appropriate restraints on the molecular geome-

try were applied.

H^1,3), 4.37 (t, J_HH= 2.5 Hz, 2 H, H²), 6.54 (d, J_HH= 8.2 Hz, 2

H, H^5–8), 6.77 (t, ³J_HH= 8.1 Hz, 2 H, H^5–8), 6.90 (t, ³J_HH= 7.9 Hz,

2 H, H^5–8), 7.59 (d, ³J_HH= 8.2 Hz, 2 H, H^5–8) ppm. IR (KBr): ν

˜

CO

= 1925 (s) cm^–1. ESI⁺-MS: 742.5 [M]⁺. C₂₀H₁₄I₂O₂Ru₂·0.35C₆D₆

(771.67): calcd. C 34.4, H 1.8, found C 34.8, H 2.3.

The crystal of 11 contained two half CH₂Cl₂solvent molecules,

both at special position and both disordered, while the crystal of

17 contained three CH₂Cl₂solvent molecules. Two CH₂Cl₂solvent

molecules were also found and refined for 7 and 9. The latter also

contained a half molecule of hexane, which was modeled as disor-

dered over two sites of equal occupancies, a common thermal pa-

rameter each for the CH₂and CH₃carbon atoms were assigned,

with appropriate restraints on the bond lengths. The molecule of 7

exhibited disorder of the NEt₂fragment over two alternative sites,

the occupancies were allowed to refine and summed to unity, giving

an approximate 65:35 ratio. The thermal parameters for the corre-

sponding atoms were restrained to be the same, as were the bond

lengths.

(c) Reaction with Diethyl Dithiocarbamate in the Presence of

TMNO: A solution of 18 (30.0 mg, 0.08 mmol) and TMNO·2H₂O

(17.0 mg, 0.15 mmol) in CH₃CN (15 mL) was stirred for 30 min at

ambient temperature. The resulting dark brown solution was trans-

ferred via a cannula into a flask containing NaS₂CNEt₂·3H₂O

(17.0 mg, 0.80 mmol) and the mixture was stirred for 1 h, giving a

dirty green solution. This was concentrated to about 10 mL and

adsorbed onto Celite (200 mg). Solvent was removed under vacuo

and the Celite mixture was loaded onto a silica gel column

(5ϫ2 cm) prepared in n-hexane. Elution gave a yellow eluate in

toluene (about 25 mL), which, upon removal of solvent, afforded a

yellow solid of (Ind)Ru(CO)(η²-S₂CNEt₂) (21) (16 mg, 55% yield).

1

3

For complex 12, two half molecules of THF were found. These

were modeled with a common thermal parameter each for the O

and C atoms, and with appropriate restraints on the bond lengths.

The molecule of 12 exhibited disorder, which was modeled with

two alternative sites for the Ru atom and the PEt₂fragment. The

occupancies were initially refined in an all-isotropic model and then

fixed at 0.9 and 0.1 for the two sites, respectively, in the final model.

Appropriate restraints similar to those described for the solvent

molecule above were also applied. The molecular structure of 20

exhibits crystallographic mirror symmetry, with the mirror plane

passing through the two Ru atoms and bisecting the Ru₂S₂plane.

Data for 21: H NMR (C₆D₆): δ = 0.61 (t, J_HH= 7.1 Hz, 6 H, N-

3

CH₂CH₃), 2.94 (q, J_HH= 7.1 Hz, 4 H, N-CH₂), 4.85 (t, J_HH

=

2.6 Hz, 1 H, H²), 5.16 (d, J_HH= 2.6 Hz, 2 H, H^1,3), 6.91–6.96 (4-

line m, 2 H, H^5–8), 7.12–7.16 (m, 2 H, H^5–8) ppm. ¹³C NMR

(C₆D₆): δ = 11.7 (CH₃), 43.1 (N–CH₂), 64.6 (C^1,3), 85.8 (C²), 113.1

(C^4,9), 124.4, 126.3 (C^5,8and C^6,7), 201.5 (SCN), 215.3 (CO) ppm.

3

IR (THF): ν_CO= 1931 (s) cm^–1. FAB⁺-MS: 393.0 [M]⁺, 364.9 [M –

˜

CO]⁺. C₁₅H₁₇NORuS₂(392.5): calcd. C 45.9, H 4.4, N 3.6, S 16.3,

found C 45.8, H 4.2, N 3.2, S 16.0.

(d) Reaction with Isopropyl Xanthate in the Presence of TMNO: A

similar reaction using KS₂COiPr (14.0 mg, 0.08 mmol) to replace

NaS₂CNEt₂·3H₂O resulted in a brownish yellow solution. A similar

chromatographic workup gave a yellow solution in toluene (about

25 mL), which, upon removal of solvent, afforded an orange oil.

Recrystallization of the orange oil in hexane gave yellow crystals

of (Ind)Ru(CO)(η²-S₂COiPr) (22) (23.0 mg, 81% yield).

CCDC-626123 to -626131 contain the supplementary crystallo-

graphic data for this paper. These data can be obtained free of

charge from The Cambridge Crystallographic Data Centre via

www.ccdc.cam.ac.uk/data_request/cif.

Computation: The initial geometries of the ruthenium complexes

Data of 22: ¹H NMR (C₆D₆): δ = 0.80 (d, ³J_HH= 6.2 Hz, 6 H,CH₃), used for the calculations were based on some of the X-ray crystal

4.77 (t, J_HH= 2.6 Hz, 1 H, H²), 5.00 (sept, J_HH= 6.2 Hz, 1 H, structures obtained. The structures of the reactants, products, and

3

O-CH), 5.07 (d, J_HH= 2.6 Hz, 2 H, H^1,3), 6.83–6.87 (4-line m, 2

transition state were fully optimized at the B3LYP density func-

tional theory together with LANL2DZ basis sets. Harmonic fre-

3

H, H^5–8), 6.95–6.98 (4-line m, 2 H, H^5–8) ppm. ¹³C NMR (CD₂Cl₂):

δ = 21.4 (CH₃), 65.1 (C^1,3), 76.8 (O-CH), 85.8 (C²), 111.6 (C^4,9), quencies were calculated at the optimized geometries to character-

124.8, 127.4 (C^5,8and C^6,7), 199.4 (SCO), 231.9 (CO) ppm. IR

(THF):

2041 (s) cm^–1. EI-MS: 380.1 [M]⁺, 352.0 quencies, or transition states with one imaginary frequency, and to

ize stationary points as equilibrium structures, with all real fre-

ν

˜

=

CO

[M – CO]⁺, 217.0 [M – CO–S₂COC₃H₇]⁺. HR-FAB⁺-MS for

C₁₄H₁₄O₂RuS₂[M]⁺: m/z (%)

379.9563 (found), 379.9473

(calcd.), for C₁₃H₁₄ORuS₂[M – CO]⁺: m/z (%) = 351.9599 (found),

evaluate zero-point energy (ZPE) corrections. For all cases in which

transition states have been found, these states were verified by fol-

lowing the path traced by the reaction coordinate, which was the

=

3838

www.eurjic.org

Eur. J. Inorg. Chem. 2007, 3827–3840

(Indenyl)ruthenium Complexes Containing Dithiolate Ligands

Table 3. Crystal and structure refinement data.

FULL PAPER

Compound

4a·1.5(Et₂O)

9·2(CH₂Cl₂)·0.5(C₆H₁₄)

12·(C₄H₈O)

Formula

Formula mass

Space group (crystal system)

C₅₄H₆₀FeNO_1.50P₂RuS₂

1030.01

P1

C₅₁H₅₁Cl₄FeOP₂RuS₂

1104.70

P1

C₅₁H₅₃FeOP₃RuS₂

995.88

P1

¯

Crystal system

triclinic

Unit cell dimensions

a [Å]

b [Å]

c [Å]

13.7226(9)

13.7314(9)

14.4562(9)

75.104(2)

69.530(2)

84.632(2)

2466.2(3)

2

1.387

0.790

11.6305(7)

14.5322(8)

15.8226(9)

104.580(1)

109.823(1)

95.273(1)

2388.2(2)

2

1.536

1.036

11.3272(14)

13.4646(17)

16.962(2)

105.351(3)

94.667(3)

99.352(3)

2440.4(5)

α [°]

β [°]

γ [°]

Cell volume [Å³]

Z

2

D_calcd(g/cm³)

Absorption coefficient [mm^–1]

F(000) electrons

Crystal size [mm³]

θ range for data collection [°]

Index ranges

1.355

0.826

1028

0.28ϫ0.20ϫ0.12

2.09–26.37

–14 Յ h Յ 14

–16 Յ k Յ 16

0 Յ l Յ 21

31598

1070

1130

0.29ϫ0.10ϫ0.04

2.11–26.37

–16 Յ h Յ 17

–16 Յ k Յ 17

0 Յ l Յ 18

33018

0.32ϫ0.24ϫ0.11

2.17–29.69

–16 Յ h Յ 14

–20 Յ k Յ 18

0 Յ l Յ 21

33852

Reflections collected

Independent reflections

Max. and min. transmission

Data/restraints/parameters

Gof

10064

12251

9971

0.9691–0.8033

10064/15/577

1.167

0.8945–0.7327

12251/4/555

1.099

0.9074–0.8017

9971/26/571

1.173

Final R indices [I Ͼ 2σ (I)]

R₁= 0.0728

wR₂= 0.1325

R₁= 0.1051

wR₂= 0.1434

1.058 and –0.591

R₁= 0.0484

wR₂= 0.1162

R₁= 0.0540

wR₂= 0.1203

1.462 and –0.893

R₁= 0.0861

wR₂= 0.2272

R₁= 0.1024

wR₂= 0.2371

1.512 and –1.322

R indices (all data)

Largest diff. peak and hole [e/Å³]

Compound

16

20

21

Formula

Formula mass

C₄₇H₄₁Cl₂P₃RuS₂

934.80

C₁₀H₇IORu

371.13

C₁₅H₁₇NORuS₂

392.49

Space group (crystal system)

Crystal system

P2₁/C

monoclinic

Pnma

orthorhombic

P2₁/c

monoclinic

Unit cell dimensions

a [Å]

b [Å]

c [Å]

11.4645(6)

44.244(2)

8.3165(5)

90

19.462(2)

9.5125(12)

19.7207(15)

90

11.6373(9)

7.1854(5)

19.7207(15)

90

α [°]

β [°]

γ [°]

90.321(2)

90

4218.3(4)

4

1.472

0.745

90

1999.2(4)

8

2.466

4.611

1376

0.18ϫ0.11ϫ0.05

2.09 to 26.37

0 Յ h Յ 24

0 Յ k Յ 11

0 Յ l Յ 13

12455

103.900(2)

90

1600.7(2)

4

1.629

1.234

Cell volume [Å³]

Z

D_calcd(g/cm³)

Absorption coefficient [mm^–1]

F(000) electrons

Crystal size [mm³]

θ range for data collection [°]

Index ranges

1912

792

0.20ϫ0.16ϫ0.10

0.92–25.00

–11 Յ h Յ 13

–52 Յ k Յ 52

–9 Յ l Յ 9

24515

0.34ϫ0.20ϫ0.14

1.80 to 27.49

–11 Յ h Յ 15

–9 Յ k Յ 9

–21 Յ l Յ 25

10941

Reflections collected

Independent reflections

Max. and min. transmission

Data/restraints/parameters

Gof

7415

2162

3648

0.9292–0.8653

7415/0/496

1.310

0.8022–0.4908

2162/0/130

1.335

0.8462–0.6790

3648/0/183

1.172

Final R indices [I Ͼ 2σ (I)]

R₁= 0.0916

wR₂= 0.1609

R₁= 0.1113

wR₂= 0.1674

1.108 and –1.358

R₁= 0.0580,

wR₂= 0.1698

R₁= 0.0580,

wR₂= 0.1698

3.170 and –1.211

R₁= 0.0414

wR₂= 0.0985

R₁= 0.0460

wR₂= 0.1011

0.585 and –0.351

R indices (all data)

Largest diff. peak and hole [e/Å³]

mode with the imaginary frequency. These displacements were in-

complex) or back to the reactants (the η⁵complex). All calculations

deed along the reaction pathways leading to the products (the η³

were performed using the Gaussian 03 suite of programs.^[28]

Eur. J. Inorg. Chem. 2007, 3827–3840

www.eurjic.org

3839

L. Y. Goh et al.

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Received: January 20, 2007

Published Online: June 29, 2007

3840

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Eur. J. Inorg. Chem. 2007, 3827–3840

Article Doi

Synthetic, X-ray diffraction, electrochemical, and density functional theoretical studies of (indenyl)ruthenium complexes containing dithiolate ligands

DOI: 10.1002/ejic.200700070

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Article abstract of DOI:10.1002/ejic.200700070

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