Spectroscopic, structural and theoretical investigation of alkenyl ruthenium complexes supported by sulfur-nitrogen mixed-donor ligands

Article abstract of DOI:10.1002/ejic.200600241

A series of molecules bearing both sulfur and nitrogen donors has been investigated as ligands for σ-alkenyl ruthenium complexes. On deprotonation, the ligands, 4-amino-2-mercaptopyrimidine (HL₁), 2-amino-5-mercapto-1,3,4-thiadiazole (HL₂), 2-mercaptothiazoline (HL₃), 4-hydroxy-2-mercaptopyrimidine (HL₄) and 2-mercaptoquinoline (HL₅) all react with alkenyl complexes of the form [RuRCl(CO)(BTD)-(PPh₃)₂] [R = CH=CHC ₆H₅, CH=CHC₆H₄Me-4, C(C≡CPh)= CHPh; BTD = 2,1,3-benzothiadiazole] through loss of chloride and BTD ligands to yield [RuR(L)(CO)(PPh₃)₂]. Four of these ligands have alternative potential coordination modes and donor groups. In all cases complexation occurs to form four-membered nitrogen-sulfur chelates with the pendant amino or hydroxy functionality playing no role in coordination. In the case of the 4-aminopyrimidine-2-thiolate (L₁) ligand, this was confirmed by a single-crystal X-ray study. 2-Mercaptothiazoline (L₃) has the ability to coordinate through two sulfur donors, however, chelation to nitrogen and sulfur donors is preferred as demonstrated by a structural study. This observation is supported by theoretical calculations, which show that a complex displaying the nitrogen-sulfur chelate is of significantly lower energy than one bonded to the ligand through two sulfur donors, despite lone pairs being available in both cases. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.

Full text of DOI:10.1002/ejic.200600241

FULL PAPER
DOI: 10.1002/ejic.200600241
Spectroscopic, Structural and Theoretical Investigation of Alkenyl Ruthenium
Complexes Supported by Sulfur–Nitrogen Mixed-Donor Ligands
James D. E. T. Wilton-Ely,*[a] Ming Wang,[b] David M. Benoit,[c] and Derek A. Tocher[b]
Keywords: Mixed-donor ligands / Ruthenium / Alkenyl / Thiolate / Ab initio / Density functional theory
A series of molecules bearing both sulfur and nitrogen do-
nors has been investigated as ligands for σ-alkenyl ruthe-
nium complexes. On deprotonation, the ligands, 4-amino-2-
mercaptopyrimidine (HL1), 2-amino-5-mercapto-1,3,4-thia-
diazole (HL2), 2-mercaptothiazoline (HL3), 4-hydroxy-2-
mercaptopyrimidine (HL4) and 2-mercaptoquinoline (HL5) all
react with alkenyl complexes of the form [RuRCl(CO)(BTD)-
(PPh3)2] [R = CH=CHC6H5, CH=CHC6H4Me-4, C(CϵCPh)=
CHPh; BTD = 2,1,3-benzothiadiazole] through loss of chlo-
ride and BTD ligands to yield [RuR(L)(CO)(PPh3)2]. Four of
these ligands have alternative potential coordination modes
and donor groups. In all cases complexation occurs to form
four-membered nitrogen–sulfur chelates with the pendant
amino or hydroxy functionality playing no role in coordina-
tion. In the case of the 4-aminopyrimidine-2-thiolate (L1) li-
gand, this was confirmed by a single-crystal X-ray study. 2-
Mercaptothiazoline (L3) has the ability to coordinate through
two sulfur donors, however, chelation to nitrogen and sulfur
donors is preferred as demonstrated by a structural study.
This observation is supported by theoretical calculations,
which show that a complex displaying the nitrogen–sulfur
chelate is of significantly lower energy than one bonded to
the ligand through two sulfur donors, despite lone pairs be-
ing available in both cases.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2006)
Introduction
The alkenyl ligand is an important member of the σ-
organyl ligand family due to its presence as an intermediate
in many catalytic reactions, and has attracted substantial
interest over the last 40 years. Alkenyl complexes are known
for many metals. This is largely due to well-established syn-
thetic routes such as hydrometallation and the reaction of
coordinated alkynes with electrophiles or nucleophiles
(Scheme 1).[1]
Since the discovery of hydrometallation of alkynes by the
compounds [RuHCl(CO)L2/3] (L = PiPr3,[2] PPh3[3]), the re-
sulting alkenyl complexes have been the subject of much
pioneering work by the groups of Werner,[10] Esteruelas[11]
Santos,[12] and Caulton and Eisenstein[13] covering func-
tional-group transformation, ligand exchange and theoreti- Scheme 1. Common routes to alkenyl complexes: (A) RCϵCR;[2,3]
(B) Nu–, nucleophile is β to metal;[4] (C) E+, electrophile is β to
cal calculations. The hydride complexes themselves are
metal;[5] (D) Nu–, nucleophile is α to metal;[6] (E) rearrangement
known for their ability to catalyse hydrogenation,[14,15] hy-
yields alkenyl;[7] (F) H2C=C(X)R, X = halide;[8] (G) loss of H+ to
drocarbonylation[16] and hydrosilylation[15,17] reactions as
well as the formation of diynes.[18]
produce α-alkoxyalkenyls.[9]
Previous work from members of this group has concen-
trated on alkenyl complexes supported by bidentate and tri-
dentate nitrogen and sulfur donor ligands and the reactions
of these complexes.[19] This complemented work by other
groups exploring the effect of polydentate donors on the
structure and reactivity of alkenyl complexes. The majority
of this research has concentrated on the use of symmetrical,
bidentate phosphorus,[20] nitrogen[21] or chalcogen do-
nors.[22] The investigation of mixed-donor ligands has been
largely confined to simple, often homoleptic, coordination
compounds. In particular, very few organometallic com-
pounds bearing these ligands have been reported. The work
reported here is part of a programme[23] to synthesise σ-
[a] Chemistry Research Laboratory, University of Oxford,
Mansfield Road, Oxford OX1 3TA, UK
E-mail: james.wilton-ely@chem.ox.ac.uk
[b] Department of Chemistry, University College London,
20 Gordon Street, London WC1H 0AJ, UK
[c] Nachwuchsgruppe Theorie – SFB 569, Universität Ulm,
Albert-Einstein-Allee 11, 89081 Ulm, Germany
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Coordination Properties of Alkenyl Complexes of Ru with S,N Mixed-Donor Ligands
FULL PAPER
alkenyl complexes bearing mixed-donor bidentate ligands philic bonding.[30] In all these reports, the thionucleobase is
and to investigate their effect on migratory insertion reac- bonded through sulfur, in many cases as a monodentate
tions and hemilabile behaviour in these complexes.
ligand. In one study,[31] the cisplatin analogue, [PtCl2(L1)2],
Although the coordination chemistry of sulfur deriva- was prepared, in which 2-thiocytosine is bonded through
tives of nucleic bases has received sporadic attention due to the amino group, demonstrating the range of coordination
the interest in metal-based drugs,[24] the potential of thionu- options available. Only one organometallic complex (of tin)
cleobases and related molecules as sulfur–nitrogen mixed- has been reported very recently.[32]
donor ligands for organotransition-metal compounds has
been overlooked. The reactions of five such molecules with
coordinatively-saturated σ-alkenyl ruthenium complexes
bearing the labile 2,1,3-benzothiadiazole ligand are dis-
cussed below. Four of the ligands have alternative possible
coordination modes to those adopted and this aspect is ex-
plored in one case using a combination of structural and
computational methods.
Treatment of a suspension of [Ru(CH=CHC6H4Me-4)-
Cl(CO)(BTD)(PPh3)2] and 4-amino-2-mercaptopyrimidine
in dichloromethane with an ethanolic solution of sodium
methoxide led to an immediate colour change from red to
yellow. A yellow microcrystalline solid was isolated. This
gave rise to a singlet resonance in the 31P{1H} NMR spec-
trum at δ = 42.1 ppm, indicating a trans disposition of the
two phosphane ligands; a feature common to all the com-
plexes reported here. The retention of the alkenyl ligand
was confirmed by a doublet at 5.84 (JHH = 16.4 Hz) for the
β proton and a doublet of triplets to lower field for the α
proton at δ = 7.77 ppm (JHH = 16.4 Hz, JHP = 4.3 Hz) in
Results and Discussion
The organometallic starting materials used in this work
are the 2,1,3-benzothiadiazole (BTD) complexes [Ru(alk-
enyl)Cl(CO)(BTD)(PPh3)2],[25] which provide a useful alter-
native to the 16-electron starting materials, [Ru(alkenyl)-
Cl(CO)(PPh3)2]. The BTD compounds do not suffer con-
tamination by free triphenylphosphane and yield microcrys-
talline starting complexes of excellent purity, which can be
easily (re)crystallized from dichloromethane/ethanol mix-
tures.
4-Amino-2-mercaptopyrimidine (2-thiocytosine) has
been shown to play a role in E. coli transfer-RNA,[26] and
its coordination chemistry has been explored with a number
of metals.[27] Of the coinage metals, copper[28] and silver[29]
coordination complexes have been reported, and work by
1
the H NMR spectrum. The tolyl substituent was observed
as an (AB)2 system at 6.46, 6.87 ppm (JAB = 7.9 Hz) and a
methyl resonance at δ = 2.22 ppm. The mixed-donor ligand
itself was identified by a singlet at 4.37 (NH2) and doublet
resonances at 4.98 and 6.65 ppm, showing a coupling of
6.3 Hz between the pyrimidine protons. These values are
shifted to higher field compared to those at δ = 5.96 and
7.47 ppm (JHH = 7.15 Hz) in the free ligand.[33] A molecular
ion at m/z = 897 in the Fast Atom Bombardment (FAB)
mass spectrum and elemental analysis of the dichlorometh-
ane solvate confirmed the overall composition as
[Ru(CH=CHC6H4Me-4)(L1)(CO)(PPh3)2] (1) (Scheme 2).
Reaction of [Ru{C(CϵCPh)=CHPh}Cl(CO)(BTD)-
members of our group has investigated its use in supramo- (PPh3)2] with HL1 in a similar manner yielded the disubsti-
lecular networks of gold(I) based on hydrogen and auro- tuted alkynyl derivative [Ru{C(CϵCPh)=CHPh}(L1)-
Scheme 2. Alkenyl complexes bearing the mixed-donor ligands, L1–L5. (i) C4H5N3S (HL1), NaOMe; (ii) C2H3N3S2 (HL2), NaOMe; (iii)
C3H5NS2 (HL3), NaOMe; (iv) C4H4N2OS (HL4), NaOMe; (v) C9H7NS (HL5), NaOMe.
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(CO)(PPh3)2] (2), which gave rise to a ν(CϵC) absorption copper[35] and bronze.[36] The properties of its metal com-
of low intensity at 2147 cm–1 for the enynyl ligand. A plexes have been examined in the inhibition of carbonic
broadened singlet at 4.5 ppm was observed in the 1H NMR anhydrase.[37] [Ru(CH=CHPh)Cl(CO)(BTD)(PPh3)2] reacts
spectrum for the NH2 group. In addition to a singlet for with HL2 in the presence of base to provide
the vinylic proton (δ = 6.13 ppm) and resonances due to the [Ru(CH=CHPh)(L2)(CO)(PPh3)2] (3) in good yield. The
aromatic protons of the alkenyl substituents, two doublets presence of the mixed-donor ligand was indicated in the 1H
were observed at δ = 5.12 and 7.69 ppm (JHH = 6.3 Hz) in NMR spectrum by a singlet at δ = 5.22 ppm for the NH2
the 1H NMR spectrum of 2. The chemical shift of the latter group, along with typical spectroscopic features for the alk-
resonance was shifted by approximately 1 ppm downfield enyl ligand. The formulation of the structure (Scheme 2)
with respect to the same feature in complex 1. A possible was based on these data, a molecular ion at m/z = 889 and
explanation for this observation is provided by the crystal elemental analysis.
structure obtained from single crystals of 2, grown by slow
diffusion of ethanol into a dichloromethane solution of the ligand for palladium centres[38] and to generate polymeric
complex (Figure 1).
clusters of CuI and AgI.[39] It has also been employed as a
Thiazoline-2-thiolate (L3) has been used as a bridging
An interaction of around 2.6 Å was observed between ligand in precursor complexes for the deposition of cad-
the triple bond of the enynyl ligand (C10–C11) and the clos- mium selenide.[40] However, the potential of the ligand as a
est proton of the pyrimidine ring (C19–H). The presence bidentate donor has not been widely explored.[41]
of this interaction in solution could explain the apparent
The yellow compound [Ru(CH=CHC6H4Me-4)(L3)-
deshielding of the proton and hence its shift to lower field. (CO)(PPh3)2] (4) was isolated from the reaction of HL3 with
Such CH–π interactions are often found in terminal al- [Ru(CH=CHC6H4Me-4)Cl(CO)(BTD)(PPh3)2] and base
kynes,[34] such as in ( )-3-phenylbut-l-ynol, where the dis- (Scheme 2). Similar spectroscopic features for the alkenyl
1
tance to the midpoint of the triple bond is 2.62 Å.[34c] On ligand were observed in the H NMR spectrum as for 1.
the basis of this evidence, the proton resonances at δ = 5.12 Two triplets were also present in the spectrum at δ = 2.13
and 7.69 ppm were assigned to the H5 and H6 protons, and 2.36 ppm, and these were assigned to the thiazoline
respectively.
ring protons showing mutual coupling of 8.2 Hz. The corre-
Recent reports have shown 2-amino-5-mercapto-1,3,4- sponding enynyl derivative, [Ru{C(CϵCPh)=CHPh}(L3)-
thiadiazole (HL2) to be an effective corrosion inhibitor for (CO)(PPh3)2] (5), was prepared in an identical manner. Co-
Figure 1. Structure of [Ru{C(CϵCPh)=CHPh}(L1)(CO)(PPh3)2] (2). Selected bond lengths [Å] and angles [°]: Ru1–C1 1.827(4), Ru1–C2
2.111(4), Ru1–N1 2.176(3), Ru1–P2 2.3755(11), Ru1–P1 2.3918(11), Ru1–S1 2.5131(11), S1–C18 1.730(4), N1–C18 1.346(5), C2–C3
1.340(5), C10–C11 1.205(6), C1–Ru1–C2 89.55(16), C2–Ru1–N1 99.97(13), C1–Ru1–P2 89.98(13), C2–Ru1–P2 94.28(11), N1–Ru1–P2
89.80(9), C1–Ru1–P1 89.93(13), C2–Ru1–P1 90.23(11), N1–Ru1–P1 89.55(9), P2–Ru1–P1 175.48(3), C1–Ru1–S1 104.98(13), N1–Ru1–S1
65.49(9), P2–Ru1–S1 89.14(4), P1–Ru1–S1 86.52(4), C18–S1–Ru1 80.18(13), C18–N1–Ru1 102.6(2), C3–C2–Ru1 126.1(3), N1–C18–S1
111.5(3).
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Coordination Properties of Alkenyl Complexes of Ru with S,N Mixed-Donor Ligands
FULL PAPER
ordination of the ligand through a thiolate linkage was ex- CHPh}(L4)(CO)(PPh3)2] (6), the hydroxy analogue of the
pected in view of the basic conditions employed and this 4-aminopyrimidine-2-thiolate complex, 2, in excellent yield
assumption was reinforced by the observation of NaCl pre- (Scheme 2). The coordination of the ligand was assumed to
cipitation during the reactions. However, it was not clear be through the N1 and sulfur donors in order to minimize
whether a bidentate chelate would be achieved through the steric interaction between the hydroxy group and the car-
sulfur or the nitrogen donor on the thiazoline ring. A theo- bonyl and enynyl ligands. Coordination of L4 is also pos-
retical study was undertaken in order to examine the mode sible as an oxygen–nitrogen mixed-donor. This seemed un-
of coordination of L3. This showed that the chelate should likely, given the thiophilicity of ruthenium(II) and was ruled
form through sulfur and nitrogen donors rather than both out by the observation of a broadened singlet at δ =
sulfur donors and revealed that there is a significant energy 1.75 ppm for the hydroxy proton. A doublet for one of the
difference between the S,S and S,N coordination modes, pyrimidine protons was noted at δ = 5.22 ppm (JHH
=
favouring the latter (Computational Section). These calcu- 7.3 Hz) which was assigned to H5 on the basis of HMQC
lations were found to be in good agreement with a later and HMBC experiments. The H6 resonance (δ = 7.43 ppm,
structural determination using single crystals of the enynyl JHH = 7.7 Hz in the free ligand[33]) was obscured by the
derivative, [Ru{C(CϵCPh)=CHPh}(L3)(CO)(PPh3)2] (5), aromatic resonances.
which were grown by slow diffusion of ethanol into a
dichloromethane solution of the complex (Figure 2).
Walton and co-workers have investigated the coordina-
tion properties of quinoline-2-thiolate (L5) with rhenium
The thionucleobase, 4-hydroxy-2-mercaptopyrimidine complexes[43] and a few examples have been isolated for mo-
(HL4), also known as 2-thiouracil, has been used to prepare lybdenum,[44] cobalt[45] and gold.[46] HL5 has also been used
coordination compounds with
a
number of met- as an analytical reagent for the determination of nickel,
als.[42,27a,27k,31] Recent work has investigated the redox copper and palladium.[47] Reaction of a suspension of
properties of complexes using 2-thiouracil as a bridging li- [Ru(CH=CHC6H4Me-4)Cl(CO)(BTD)(PPh3)2] with HL5
gand between ruthenium centres.[27m] However, no organ- and sodium methoxide resulted in the formation of the yel-
oruthenium species stabilized by this ligand have been re- low complex [Ru(CH=CHC6H4Me-4)(L5)(CO)(PPh3)2] (7).
1
ported as far as we are aware.
The peaks observed in the H NMR spectrum for the alk-
[Ru{C(CϵCPh)=CHPh}Cl(CO)(BTD)(PPh3)2] reacted enyl ligand are similar to those seen in the spectra of 1, 3
readily with HL4 and base to yield [Ru{C(CϵCPh)= and 4. The protons of the quinoline rings are all obscured
Figure 2. Structure of [Ru{C(CϵCPh)=CHPh}(L3)(CO)(PPh3)2] (5). Selected bond lengths [Å] and angles [°]: Ru1–C1 1.827(2), Ru1–C5
2.102(2), Ru1–N1 2.1766(19), Ru1–P1 2.3667(6), Ru1–P2 2.3746(6), Ru1–S1 2.5521(6), S1–C2 1.720(2), N1–C2 1.283(3), C5–C6 1.361(3),
C13–C14 1.205(3), C1–Ru1–C5 88.28(9), C5–Ru1–N1 98.55(8), C1–Ru1–P1 88.62(7), C5–Ru1–P1 94.82(6), N1–Ru1–P1 88.95(5), C1–
Ru1–P2 87.87(7), C5–Ru1–P2 90.58(6), N1–Ru1–P2 93.88(5), P1–Ru1–P2 173.46(2), C1–Ru1–S1 108.27(7), N1–Ru1–S1 65.13(5), P1–
Ru1–S1 91.26(2), P2–Ru1–S1 84.61(2), C2–S1–Ru1 76.93(8), C2–N1–Ru1 101.39(15), N1–C2–S1 116.55(17), C6–C5–Ru1 126.48(17).
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by the resonances of the PPh3 ligands with the exception of bond length in HL3, 1.319(2) Å. These variations between
one proton, which gives rise to a doublet at δ = 7.92 ppm bonding in the ligand in free and coordinated states are
(JHH = 8.3 Hz). The overall formulation is based on these greater than those discussed for HL1 above. The bond
data, a molecular ion in the FAB mass spectrum at m/z = lengths between the donors and the ruthenium centre are
931 and elemental analysis.
essentially the same in both 2 and 5 with the exception of
the Ru1–S1 bond length, which is around 0.03 Å longer in
complex 5. Unlike the 4-aminopyrimidine-2-thiolate (L1) li-
gand, the thiazoline-2-thiolate (L3) moiety is not planar due
to the saturated C3–C4 linkage. The overall geometry of the
Structural Discussion
The structure of [Ru{C(CϵCPh)=CHPh}(L1)(CO)- structure of 5 is distorted octahedral with cis-interligand
(PPh3)2] (2) (Figure 1) has a distorted octahedral geometry angles in the range 65.13(5) – 108.27(7)°, the smallest being
with cis-interligand angles in the range 65.49(9)– due to the bite angle of the bidentate ligand. The bond
104.98(13)°. The smallest of these angles corresponds to the lengths and distances of the enynyl ligand are similar to
bite angle, N1–Ru1–S1, of the 4-aminopyrimidine-2-thiol- those found in [Ru{C(CϵCPh)=CHPh}(L1)(CO)(PPh3)2]
ate ligand (L1). The structure of 4-amino-5-methylmercap- (2).
topyrimidine has been determined[48] and can be assumed
to be a direct analogue of the free ligand, HL1. This report
revealed that the molecule exists essentially in the thione
In order to assess the relative stability of the S,N- and
form, however, on coordination to divalent ruthenium in
Computational Study
S,S-bonding
modes
available
to
the
complex,
our system, the bond lengths of L1 were observed to be
shifted towards the thiolate form. This is seen in the length-
ening of the C–S distance from 1.710(4) to 1.730(4) Å in 2,
while the N1–C18 distance shortens from 1.371(5) to
1.346(5) Å on coordination. A complex with the related li-
gand, 4-methylpyrimidine-2-thiolate (mpymt), [Ru(mpymt)-
(bpy)2]+ (bpy = 2,2Ј-bipyridine) has been reported,[42e] in
which the C–S distance [1.711(8) Å] is shorter, and the bond
length corresponding to N1–C18 [1.367(9) Å] is approxi-
mately the same as that found in 2. This indicates that com-
plexation of L1 in 2 represents a greater shift from the
thione to thiolate form than observed in the literature com-
plex. The Ru–S and Ru–N distances for the chelate in
[Ru(mpymt)(bpy)2]+ [2.408(2) and 2.103(6) Å, respectively]
are considerably shorter than the corresponding distances
in 2 of 2.513(11) and 2.176(3) Å. This is likely to be due
to the stronger trans-influence of the carbonyl and alkenyl
donors in [Ru{C(CϵCPh)=CHPh}(L1)(CO)(PPh3)2] (2)
compared to 2,2Ј-bipyridine in the literature complex. The
bite angle of L1 in 2 [65.49(9)°] is also smaller than that
of 68.2(2)° found in [Ru(mpymt)(bpy)2]+. The bond lengths
associated with the alkenyl ligand were found to be unre-
markable and fall within the typical range for these li-
gands.[49] As mentioned above (Results and Discussion), the
close proximity of the H6 proton of L1 and the triple bond
C10–C11 of the enynyl ligand appears to indicate an inter-
[Ru{C(CϵCPh)=CHPh}(L3)(CO)(PPh3)2] (5), it was de-
cided to use ab initio and density functional theory calcula-
tions to compute the optimized geometry of two model
complexes derived from structure 5. The calculations were
performed using the NWChem4.6 ab initio package[51] run-
ning on a dual processor Apple Xserve. Each optimization
was performed using analytic gradients and the default con-
vergence criteria of NWChem.
The simplest model for our computational study is ob-
tained by substituting all phenyl groups and R2 by hydrogen
atoms, thus reducing the enynyl ligand to the parent alkenyl
(Scheme 3).
1
action that is also present in solution, as suggested by H
NMR evidence.
The structure of 2-mercaptothiazoline (HL3) was only re-
ported very recently and revealed that the molecule adopts
the expected thione form in the solid state with the C–S
bond [1.6745(16) Å] displaying clear double bond charac-
ter.[50] As was found for HL1, coordination in the deproton-
ated form results in a shift of double bond character from
the C–S bond to the N–C bond involved in the chelate.
The C2–S1 distance of 1.720(2) Å found in the structure of
[Ru{C(CϵCPh)=CHPh}(L3)(CO)(PPh3)2] (5) (Figure 2) is
considerably longer than that in the free ligand and the N1–
Scheme 3. Computational model. Model A corresponds to R1
R2 = H. Model B is for R1 = CϵCCH3 and R2 = CH3. Numbering
=
C2 distance of 1.283(3) Å is shorter than the corresponding scheme is the same as that used in the structural study.
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Coordination Properties of Alkenyl Complexes of Ru with S,N Mixed-Donor Ligands
FULL PAPER
The modest size of model A, along with the use of rela- treatment of the electronic correlation. The correlated result
tivistic pseudo-potentials for each atom developed by Ste- computed using LDA brings the energy difference down to
vens, Basch and Krauss,[52] allowed us to perform fast ex- about 66 kJ·mol–1 which still indicates a very strong prefer-
ploratory calculations using both the Hartree–Fock (HF) ence of the ruthenium for S,N coordination over S,S com-
method and the local density approximation (LDA) of den- plex formation.
sity functional theory.
Table 2. Total energy differences for the S,N- and S,S-bonded ru-
thenium structures computed at various levels of ab initio theory.
The results of our calculations are shown in Table 1,
where we report a selection of metal–ligand distances. We
observe that the HF distances are much larger than those
measured in the experimental X-ray structure, in particular
for the two phosphanes and the Ru–S bond. This is to be
expected since this method does not take electronic corre-
lation into account. The LDA results for the S,N-bonded
structure on the other hand are in good agreement with
the X-ray values, showing the importance of correlation in
Level of theory E(S,N complex) – E(S,S complex)
Model A HF
LDA
Model B LDA
BP86
– 92.35 kJ·mol–1
– 65.93 kJ·mol–1
– 65.41 kJ·mol–1
– 64.91 kJ·mol–1
It has been shown that steric effects can have a great
describing the electronic structure of transition metal com- influence on the energetics of ruthenium complexes[53] and,
plexes. Moreover, the good agreement with experiment sug- to assess the influence of bulkier phosphane and alkenyl
gests that the computed values for the S,S complex, which ligands, we replaced the hydrogen atoms of our simple
was not isolated experimentally, are a plausible representa- model by methyl and propynyl groups to generate Model B
tion of the geometrical environment around the ruthenium (Scheme 3). The influence of these groups on the stability
atom in the S,S system.
of the bent ring in the S,S complex can result in an increase
In particular, we note that for both levels of theory the of the total energy difference between the S,N and S,S com-
S,S complex exhibits a strong degree of ring bending which plexes. While these groups cannot account for the overall
is absent in the S,N complex. Indeed, Table 1 shows that, steric bulk of the phenyl groups used experimentally, we
while the out-of-plane angle Ru1–S1–C2–C4 remains very expect that any important steric effects would become ap-
low for the S,N complex (about 3° to 5°), the S,S complex parent with this more limited substitution.
has out-of-plane angles between –128° and –110° which
The model B compounds were optimized using local
indicate that the hybridization of the second sulfur atom density functional theory and then further refined using a
(S2) is close to tetrahedral. This, in turn, forces the rest of gradient-corrected exchange and correlation functional
the thiazoline ring to bend out of the equatorial plane to BP86, which has been developed by Becke and Perdew.[54]
accommodate the bonding mode of both sulfur donors. The It has been shown that this exchange and correlation func-
out-of-plane angle computed for the S,N complex on the tional gives good results for transition-metal complexes[55]
other hand is in good agreement with that measured in the and ruthenium complexes containing carbonyl ligands in
X-ray structure of –4.5°.
particular.[56]
In Table 2, we observe that, for model A, the computed
Our results for these calculations are shown in Table 1
difference of total energy is in favour of the S,N complex and Table 2. First, we see that the change from model A to
in both types of calculations (HF and LDA), which is in model B has a small influence on the computed bond
line with the experimental observation. The HF method lengths and improves their agreement with the X-ray mea-
predicts a relatively large energy difference of about surements. We note a slight elongation of the Ru–P bonds
92 kJ·mol–1 which is likely to be an overestimation com- for both S,N and S,S complexes and a small contraction of
pared to the true value owing to the lack of an appropriate the Ru–S distance for the structure with the S,N coordina-
Table 1. Selected metal–ligand distances for the S,N- and S,S-bonded ruthenium complex computed at various levels of ab initio theory.
The atomic numbering scheme is identical to that in Figure 2.
S,N Complex
S,S Complex
Model A
HF
Model B
LDA
Model A
HF
Model B
LDA
Distance [Å]
X-ray
LDA
BP86
LDA
BP86
Ru1–C1
Ru1–C5
Ru1–N1
Ru1–P1
Ru1–P2
Ru1–S1
Ru1–C2
Ru1–S2
1.827(2)
2.102(2)
2.1766(19)
2.3667(6)
2.3746(6)
2.5521(6)
2.736
1.997
2.116
2.203
2.529
2.525
2.730
2.803
4.597
1.854
2.035
2.107
2.351
2.355
2.638
2.744
4.547
1.842
2.074
2.132
2.378
2.379
2.613
2.744
4.560
1.856
2.121
2.208
2.445
2.446
2.681
2.804
4.641
1.983
2.120
4.165
2.534
2.534
2.663
3.063
2.727
1.843
2.060
3.859
2.366
2.361
2.579
2.830
2.528
1.830
2.078
3.823
2.409
2.384
2.581
2.804
2.542
1.847
2.134
4.122
2.466
2.457
2.644
3.010
2.627
4.471
Out-of-plane angle
Ru1–S1–C2–C4 –4.50°
3.3°
5.0°
2.5°
2.8°
–127.9°
–108.6°
–114.8°
–123.5°
Eur. J. Inorg. Chem. 2006, 3068–3078
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
3073

J. D. E. T. Wilton-Ely, M. Wang, D. M. Benoit, D. A. Tocher
FULL PAPER
tion mode. The values for the out-of-plane angle are also ligand is composed mainly of the px orbital of the terminal
mildly affected and we see both types of complexes becom- sulfur atom but has a non-negligible contribution from the
ing slightly flatter. These observations suggest that the steric nitrogen atom, which allows a degree of π bonding with the
effects are small and indicate that our initial model (Model ruthenium centre. The presence of π ligands in the complex
A) already provided a good description of both complexes. already (e.g., the carbonyl group) means that an additional
Second, we note that the energetics of both complexes are ligand that can act as a π donor will participate more ef-
not perturbed by the increase in steric bulk of the substitu- ficiently in the bonding at the metal centre. Analysis of the
ents since the total energy differences between the S,N and molecular orbitals of the S,S complex shows that such π
S,S complexes remains at about 65 kJ·mol–1, again in favour bonding is not possible when the metal centre is bonded to
of the S,N complex.
the ligand using the S,S-configuration.
To further investigate the effects of electron correlation
In order to shed some light on a possible kinetic prefer-
on the structure and energetics of both types of complexes, ence at the ligand-binding stage for the formation of the
the structures obtained from the LDA calculations on S,N complex over the S,S complex, we computed the charge
model B were re-optimized using BP86. The resulting ge- distribution of the 2-mercaptothiazoline anionic ligand.
ometries for both complexes are shown in Figure 3. As ex- This calculation was performed using the GAMESS-US
pected, since gradient-corrected functionals such as BP86 suite of programs[57] at the Møllet-Plesset (MP2) level of
tends to elongate bonds in transition metal complexes,[55] theory with a TZV(d,p)++ basis set,[58] since it has been
we observe a lengthening of most bonds in both complexes. recognized that DFT can have problems describing
In the S,N complex, BP86 overestimates the Ru–P and the anions.[59] It should be noted that there is a large negative
Ru–S distances compared with the experimental values, region around the sulfur atom that protrudes out of the
while the other distances and the out-of-plane angle are rel- thiazoline ring (S1) and around the N atom (N1), while the
atively unaffected (see Table 1). In the case of the S,S com- sulfur atom within the thiazoline ring (S2) is mainly posi-
plex, the out-of-plane angle increases and the Ru–P, Ru–S tively charged. This charge distribution could be responsi-
bonds are longer than calculated previously using LDA.
ble for a preferential formation of a S,N complex since the
orientation of this anionic ligand with respect to a posi-
tively charged centre such as RuII will naturally lead to a
closer contact between the metal centre and the atoms S1
and N1.
Conclusions
This report details the investigation of the coordination
properties of five nitrogen–sulfur mixed-donor ligands with
alkenyl complexes of ruthenium. We believe that these are
Figure 3. Optimised structures of the S,N complex (left) and S,S the first organoruthenium examples to be reported. Al-
complex (right) for model B computed at the BP86/SBK level of
theory. Note the large out-of-plane angle in the S,S structure.
though a number of alternative coordination modes are
possible, all ligands adopt a four-membered nitrogen–sulfur
chelate, a fact confirmed crystallographically for two exam-
Gradient-corrected functionals, such as BP86, provide a
ples. In the case of the thiazoline-2-thiolate ligand, the alter-
more reliable estimation of the binding energy of transition-
native sulfur–sulfur coordination mode was investigated
computationally and found to be of much higher energy
than the observed S,N coordination, which was confirmed
metal complexes than the local density approximation.[55]
Therefore, despite the lengthening of the metal–ligand
bonds with BP86, it is interesting to note that the total en-
by a structural determination. The excellent correlation of
ergy difference between the S,N and the S,S complexes com-
structural and computational data indicates the utility of
puted with this method remains similar to the value com-
this theoretical approach in the rationalization of such com-
plexation behaviour.
puted using LDA (about 65 kJ·mol–1, see Table 2), again
pointing to a marked preference for S,N coordination.
Both models and all levels of theory used in this study
indicate that the S,N complex is thermodynamically fav-
oured over the S,S complex. There are several possible
Experimental Section
All manipulations were carried out under aerobic conditions with
reasons for the greater stability of a sulfur–nitrogen combi-
commercially available solvents and reagents, which were used as
nation. First, the S,N configuration of the 2-mercaptothiaz-
received. Infrared and NMR spectroscopy was carried out at 25 °C
oline ligand is able to approach the metal centre more
using Shimadzu FTIR 8700 (KBr plates and nujol mulls) and
closely than the ligand in the S,S arrangement. Indeed, ap-
proach of an S,S donor combination is unfavourable due to
the constraining bonding mode of the second sulfur atom
(S2), which causes out-of-plane ring bending of the rest of
Bruker AMX-300 (1H: 299.87 MHz, 31P: 121.39 MHz) spectrome-
ters respectively. Infrared spectroscopic features due to the tri-
phenylphosphane ligands have been omitted to aid clarity. FAB-
MS spectra (nitrobenzyl alcohol matrices) were measured using a
the ligand. Second, the HOMO of the 2-mercaptothiazoline VG 70-SB magnetic sector mass spectrometer. Elemental analysis
3074 Eur. J. Inorg. Chem. 2006, 3068–3078
www.eurjic.org
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Coordination Properties of Alkenyl Complexes of Ru with S,N Mixed-Donor Ligands
FULL PAPER
was performed at University College, London. Solvates were
determined by integration of the 1H NMR spectra. The
complexes
m/z (%) = 906 (3) [M+H2O]+, 888 (3) [M]+, 771 (1) [M – L3]+,
626 (6) [M 598 (2)
–
PPh3]+, [M–CO–PPh3]+.
[Ru(CH=CHC6H4CH3-4)Cl(CO)(BTD)(PPh3)2],[25] C49H43NOP2RuS2·CH2Cl2 (973.97): calcd. C 61.7, H 4.7, N 1.4;
[Ru(CH=CHPh)Cl(CO)(BTD)(PPh3)2],[25]
[Ru{C(CϵCPh)= found C 61.3, H 4.6, N 1.5.
CHPh}Cl(CO)(PPh3)2],[60] were prepared according to published
procedures. All other regents were obtained commercially.
Preparation of [Ru{C(CϵCPh)=CHPh}(L3)(CO)(PPh3)2] (5): Syn-
thesis as for using [Ru{C(CϵCPh)=CHPh}Cl(CO)(BTD)-
1
Preparation of [Ru(CH=CHC6H4Me-4)(L1)(CO)(PPh3)2] (1): (PPh3)2] (100 mg, 0.097 mmol) and 2-mercaptothiazoline (HL3)
[Ru(CH=CHC6H4Me-4)Cl(CO)(BTD)(PPh3)2] (100 mg, 0.106 (13 mg, 0.109 mmol) to provide a yellow microcrystalline product.
mmol) and 4-amino-2-mercaptopyrimidine (HL1) (15 mg, Yield: 72 mg (76%). IR (KBr/nujol): ν = 2152 [ν(CϵC)], 1917
˜
0.118 mmol) were suspended in dichloromethane (20 mL) and eth-
anol (10 mL) and treated with sodium methoxide (11 mg,
0.204 mmol) in ethanol (10 mL). The reaction was stirred for 1 h,
after which the solvent volume was concentrated under reduced
pressure until precipitation of a pale yellow product was complete.
This was washed with water (5 mL), ethanol (5 mL) and hexane
[ν(CO)], 1591, 1574, 1302, 1049, 941, 914 cm–1. 31P{1H} NMR
(CDCl3): δ = 39.6 ppm. 1H NMR (CDCl3): δ = 2.08, 2.88 (t×2,
JHH = 8.0 Hz, 2×2 H, C3H4NS2), 6.08 (s, 1 H, RuC=CH), 6.98–
7.81 (m, 30 H+10 H, PC6H5 +C6H5) ppm. FAB-MS: m/z (%) =
973 (2) [M]+, 856 (3) [M – L3]+, 771 (2) [M – alkenyl]+, 711 (1)
[M – PPh3]+, 684 (8) [M–CO–PPh3]+. C56H45NOP2RuS2 (975.13):
(10 mL). Yield: 68 mg (72%). IR (KBr/nujol): ν = 1923 [ν(CO)], calcd. C 69.0, H 4.7, N 1.4; found C 69.0, H 4.6, N 1.2.
˜
1614, 1572, 1545, 1313, 1256, 1186 cm–1. 31P{1H} NMR (CDCl3):
δ = 42.1 ppm. H NMR (CDCl3): δ = 2.22 (s, 3 H, CH3), 4.37 (s,
2 H, NH2), 4.98, 6.65 [d×2, JHH = 6.3 Hz, 2×1 H, C4H2(NH2)-
Preparation of [Ru{C(CϵCPh)=CHPh}(L4)(CO)(PPh3)2] (6):
[Ru{C(CϵCPh)=CHPh}Cl(CO)(BTD)(PPh3)2] (100 mg, 0.097
mmol) and 4-hydroxy-2-mercaptopyrimidine (HL4) (14 mg,
1
N2S], 5.84 (d, JHH = 16.4 Hz, 1 H, Hβ), 6.46, 6.87 [(AB)2, JAB
=
0.109 mmol) were suspended in dichloromethane (20 mL) and eth-
anol (10 mL) and treated with sodium methoxide (10 mg,
0.185 mmol) in ethanol (10 mL). The reaction was stirred for 1 h,
after which all solvent was removed. The residue was dissolved in
dichloromethane (10 mL) and filtered through diatomaceous earth
to remove NaCl. Diethyl ether (40 mL) was slowly added to pre-
cipitate the pale yellow product. This was washed with diethyl ether
(10 mL) and hexane (10 mL). Yield: 85 mg (89%). IR (KBr/nujol):
7.9 Hz, 4 H, C6H4], 7.25, 7.58 (m×2, 30 H, C6H5), 7.77 (dt, JHH
= 16.4 Hz, JHP = 4.3 Hz, 1 H, Hα) ppm. FAB-MS: m/z (%) = 897
(1) [M]+, 780 (1) [M
– –
alkenyl]+, 635 (2) [M PPh3]+.
C50H43N3OP2RuS·CH2Cl2 (981.93): calcd. C 62.4, H 4.6, N 4.3;
found C 62.8, H 4.8, N 4.3.
Preparation of [Ru{C(CϵCPh)=CHPh}(L1)(CO)(PPh3)2] (2): Syn-
thesis as for
1 using [Ru{C(CϵCPh)=CHPh}Cl(CO)(BTD)-
(PPh3)2] (100 mg, 0.097 mmol) and 4-amino-2-mercaptopyrimidine
(HL1) (14 mg, 0.110 mmol) to provide a yellow product. Yield:
ν = 2151 [ν(CϵC)], 1927 [ν(CO)], 1650, 1595, 1275, 1184, 976,
˜
914 cm–1. 31P{1H} NMR (CDCl3): δ = 40.3 ppm. 1H NMR
72 mg (76%). IR (KBr/nujol): ν = 2147 [ν(CϵC)], 1913 [ν(CO)], (CDCl3): δ = 1.75 (br. s, 1 H, OH), 5.22 [d, JHH = 7.3 Hz, 1 H,
˜
1611, 1580, 1537, 1312, 1186, 972, 914 cm–1. 31P{1H} NMR
(CDCl3): δ = 40.1 ppm. 1H NMR (CDCl3): δ = 4.5 (br. s, 2 H,
NH2), 5.12, 7.69 [d×2, JHH = 6.3 Hz, 2×1 H, C4H2(NH2)N2S],
6.13 (s, 1 H, RuC=CH), 6.78 (d, JHH = 7.4 Hz, 2 H, ortho-C6H5),
6.95 (t, JHH = 7.4 Hz, 1 H, para-C6H5), 7.27, 7.61 (m×2, 30 H +
7 H, PC6H5 + C6H5) ppm. FAB-MS: m/z (%) = 982 (9) [M]+, 856
(3) [M – L1]+, 779 (3) [M – alkenyl]+, 720 (5) [M – PPh3]+, 692 (16)
[M–CO–PPh3]+. C57H45N3OP2RuS (983.09): calcd. C 69.6, H 4.6,
N 4.3; found C 69.6, H 4.5, N 4.3.
C5H2(OH)N2S], 6.08 (s, 1 H, RuC=CH), 6.76 (d, JHH = 7.7 Hz,
2
H, ortho-C6H5), 6.98–7.72 [m, 30 H+8 H+1 H,
PC6H5 +C6H5 +C5H2(OH)N2S] ppm. FAB-MS: m/z (%) = 984 (1)
[M]+, 857 (0.2) [M – L4]+, 781 (0.6) [M – alkenyl]+, 722 (0.2) [M –
PPh3]+, 694 (1.5) [M–CO–PPh3]+, 491 (0.6) [M – alkenyl–CO–
PPh3]+. C57H44N2O2P2RuS·0.75CH2Cl2 (1047.77): calcd. C 66.2, H
4.4, N 2.7; found C 66.2, H 4.4, N 3.0.
Preparation of [Ru(CH=CHC6H4Me-4)(L5)(CO)(PPh3)2] (7):
[Ru(CH=CHC6H4Me-4)Cl(CO)(BTD)(PPh3)2] (100 mg, 0.106
Preparation of [Ru(CH=CHPh)(L2)(CO)(PPh3)2] (3): Synthesis as mmol) and 2-mercaptoquinoline (HL5) (19 mg, 0.118 mmol) were
for using [Ru(CH=CHPh)Cl(CO)(BTD)(PPh3)2] (100 mg, suspended in dichloromethane (20 mL) and ethanol (10 mL) and
1
0.108 mmol) and 2-amino-5-mercapto-1,3,4-thiadiazole (HL2)
(16 mg, 0.121 mmol) to provide a pale yellow-green product. Yield:
treated with sodium methoxide (11 mg, 0.204 mmol) in ethanol
(10 mL). The reaction was stirred for 1 h, after which the solvent
79 mg (82%). IR (KBr/nujol): ν = 1921 [ν(CO)], 1595, 1580, 1553, was concentrated under reduced pressure until precipitation of a
˜
1310, 1184, 972, 847 cm–1. 31P{1H} NMR (CDCl3): δ = 43.7 ppm. yellow product had begun. The flask was then kept at –20 °C for
1H NMR (CDCl3): δ = 5.22 (s, 2 H, NH2), 5.89 (d, JHH = 15.7 Hz, 4 hours. The resulting precipitate was washed with water (5 mL),
1 H, Hβ), 6.34 (d, JHH = 7.5 Hz, 2 H, ortho-C6H5), 6.82 (t, JHH
=
cold ethanol (5 mL) and hexane (10 mL). Yield: 76 mg (77%). Al-
7.5 Hz, 1 H, para-C6H5), 6.90 (t, JHH = 7.4 Hz, 2 H, meta-C6H5), though the product is partially soluble in ethanol, it can be recrys-
7.30–7.53 (m, 30 H, PC6H5), 7.94 (dt, JHH = 15.7 Hz, JHP = 3.2 Hz, tallised from dichloromethane/ethanol mixtures. IR (NaCl/nujol):
1 H, Hα) ppm. FAB-MS: m/z (%) = 889 (45) [M]+, 786 (20) [M –
ν = 1913 [ν(CO)], 1591, 1545, 1504, 1296, 1184, 1163, 1109, 974,
˜
alkenyl]+, 627 (12) [M – PPh3]+. C48H41N3OP2RuS2·1.5CH2Cl2 874, 845, 814 cm–1. 31P{1H} NMR (C6D6): δ = 35.6 ppm. 1H NMR
(1030.42): calcd. C 57.7, H 4.3, N 4.1; found C 57.5, H 4.0, N 4.3.
(C6D6): δ = 2.16 (s, 3 H, CH3), 6.09, 6.59 [(AB)2, JAB = 8.7 Hz, 4
H, C6H4], 6.64 (dt, JHH = 16.7 Hz, JHP = 2.0 Hz, 1 H, Hβ), 6.81–
7.16, 7.36–7.78 (m×2, 30 H+5 H, C6H5 +C9H6NS), 7.92 (d, JHH
= 8.3 Hz, 1 H, C9H6NS), 8.65 (dt, JHH = 16.7 Hz, JHP = 3.5 Hz,
1 H, Hα) ppm. FAB-MS: m/z (%) = 931 (4) [M]+, 669 (7)
[M – PPh3]+, 641 (8) [M–CO–PPh3]+, 524 (7) [M – alkenyl–CO–
PPh3]+. C55H45NOP2RuS·0.25CH2Cl2 (952.28): calcd. C 69.7, H
4.8, N 1.5; found C 69.9, H 4.8, N 1.5.
Preparation of [Ru(CH=CHC6H4Me-4)(L3)(CO)(PPh3)2] (4): Syn-
thesis as for
1 using [Ru(CH=CHC6H4Me-4)Cl(CO)(BTD)-
(PPh3)2] (100 mg, 0.106 mmol) and 2-mercaptothiazoline (HL3)
(14 mg, 0.117 mmol) to provide a yellow product. Yield: 77 mg
(82%). IR (KBr/nujol): ν = 1906 [ν(CO)], 1573, 1304, 1188, 1045,
˜
941, 831 cm–1. 31P{1H} NMR (CDCl3): δ = 40.4 ppm. 1H NMR
(CDCl3): δ = 2.13, 2.36 (t×2, JHH = 8.2 Hz, 2×2 H, C3H4NS2),
2.26 (s, 3 H, CH3), 5.84 (d, JHH = 16.5 Hz, 1 H, Hβ), 6.60, 6.92 X-ray Crystallography: Crystals of complexes 2 and 5 were grown
[(AB)2, JAB = 7.93 Hz, 4 H, C6H4], 7.33, 7.69 (m×2, 30 H, C6H5), by slow diffusion of ethanol into dichloromethane solutions of the
7.84 (dt, JHH = 16.5 Hz, JHP = 3.5 Hz, 1 H, Hα) ppm. FAB-MS: complexes. A single crystal of each compound was mounted on a
Eur. J. Inorg. Chem. 2006, 3068–3078
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
3075

J. D. E. T. Wilton-Ely, M. Wang, D. M. Benoit, D. A. Tocher
FULL PAPER
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1995, 14, 4685–4696.
glass fibre and all geometric and intensity data were taken from this
sample with a Bruker SMART APEX CCD diffractometer using
graphite-monochromated Mo-Kα radiation (λ = 0.71073 Å). Data
reduction and integration was carried out with SAINT+ and ab-
sorption corrections applied using the program SADABS. The
structures were solved by direct methods and developed using alter-
nating cycles of least-squares refinement and difference-Fourier
synthesis. All non-hydrogen atoms were refined anisotropically. Hy-
drogen atoms were placed in calculated positions and their thermal
parameters linked to those of the atoms to which they were at-
tached (riding model). Structure solution and refinement used the
SHELXTL PLUS V6.10 program package.[61] See Table 3 for se-
lected crystal data.
[5]
[6]
[7]
[8]
[9]
Table 3. Crystal data for compounds 2 and 5.
[10]
2
5·1.5(CH2Cl2)
Chemical formula
Fw
C57H45N3OP2RuS
983.03
C57.5H48Cl3NOP2RuS2
1102.45
Crystal system
Crystal colour
monoclinic
yellow
monoclinic
yellow
Crystal size [mm]
Space group
0.48×0.12×0.10
C2/c
0.24×0.22×0.12
P21/n
a [Å]
b [Å]
c [Å]
α [°]
28.321(3)
19.249(2)
21.145(3)
90
13.0473(8)
22.7831(14)
17.5285(11)
90
[11]
β [°]
γ [°]
V [Å3]
119.139(2)
90
10068(2)
8
104.5250(10)
90
5043.9(5)
4
Z
Calculated density [g/cm3]
1.297
1.452
T [K]
µ(Mo-Kα) [mm–1
F(000)
293(2)
0.458
4048
150(2)
0.658
2260
]
Reflections collected
Unique reflections (Rint
R1 [IϾ2σ(I)]
43639
12004 (0.0563)
0.0617
44202
12093 (0.0304)
0.0405
)
wRЈ2 (all data)
0.1832
0.0952
1.084, –1.214
Residual e·Å–3 (max., min.) 1.540, –1.20
CCDC-263406 and -263407 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.
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Acknowledgments
J. D. E. T. W.-E. gratefully acknowledges the Ramsay Memorial
Trust for provision of a Fellowship and Merton College, Oxford,
for a Fitzjames Fellowship. We thank the Department of Chemistry
at UCL, the University of London Central Research Fund and the
UCL Graduate School for funding and Johnson Matthey Ltd. for
a generous loan of ruthenium salts.
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Coordination Properties of Alkenyl Complexes of Ru with S,N Mixed-Donor Ligands
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Eur. J. Inorg. Chem. 2006, 3068–3078