Synthesis and substitution reactions of dichlorobis-triphenylphosphine [2-(N-(2-pyridinium-2-yl)-carbamoyl-N-)-pyridine]ruthenium(II)

Article abstract of DOI:10.1016/S0277-5387(01)00706-9

Spectroscopic and crystallographic studies show that 2-(N-(2-pyridyl)carbamoyl)pyridine (HL) in both its neutral and deprotonated forms, coordinates ruthenium(II) via the amidato- and pyridine-nitrogen atoms thereby forming five-membered rings. In neutral [Ru(HL)(PPh₃)₂Cl₂], HL exists as a zwitterion and the molecular structure is stabilised, in part, by an intramolecular Cl···N interaction. Reaction of the title complex with bidentate chelating ligands leads to the replacement of two chlorides by the bidentate ligands, resulting in the formation of the mixed-ligand complexes. There is deprotonation of the zwitterionic HL in the mixed-ligand complexes.

Full text of DOI:10.1016/S0277-5387(01)00706-9

Polyhedron 20 (2001) 1815–1820
www.elsevier.com/locate/poly
Synthesis and substitution reactions of
dichlorobis-triphenylphosphine[2-(N-(2-pyridinium-2-yl)-
carbamoyl-N−)-pyridine]ruthenium(II)
Sujit Dutta a, Pabitra K. Bhattacharya* a,1, Ernst Horn b,c, Edward R.T. Tiekink* d,2
a Department of Chemistry, Faculty of Science, M.S. Uni6ersity of Baroda, Baroda 390 002 Gujarat, India
b Department of Chemistry, Rikkyo Uni6ersity, Nishi-Ikebukuro, Tokyo 171-8501, Japan
c Tsukuba Ad6anced Research Alliance, Uni6ersity of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
d Department of Chemistry, The Uni6ersity of Adelaide, 5005 Australia
Received 19 October 2000; accepted 22 January 2001
Abstract
Spectroscopic and crystallographic studies show that 2-(N-(2-pyridyl)carbamoyl)pyridine (HL) in both its neutral and
deprotonated forms, coordinates ruthenium(II) via the amidato- and pyridine-nitrogen atoms thereby forming five-membered
rings. In neutral [Ru(HL)(PPh3)2Cl2], HL exists as a zwitterion and the molecular structure is stabilised, in part, by an
intramolecular Cl···N interaction. Reaction of the title complex with bidentate chelating ligands leads to the replacement of two
chlorides by the bidentate ligands, resulting in the formation of the mixed-ligand complexes. There is deprotonation of the
zwitterionic HL in the mixed-ligand complexes. © 2001 Elsevier Science Ltd. All rights reserved.
Keywords: Ru complexes; Linkage isomers; Amide ligands
[Ru(L)(PPh3)2(L%)]ClO4 by the deprotonation of HL,
are also reported.
1. Introduction
The location of an amide linkage between two pyri-
Linkage isomers of ruthenium complexes with amide
dine rings allows the ligand HL, to function as an
ligands have received due attention in the context of
ambidentate chelating ligand. Thus, for example, a
transition metal-peptide chemistry [1]. However, these
five-membered chelate ring involving the pyridyl nitro-
studies are mainly limited to systems featuring tetra-
gen, Na, and either of the oxygen atom (1) or the
and penta-ammineruthenium(II/III). Both O-bonded
and N-bonded linkage isomers are known for glyci-
namide chelated to the tetraammineruthenium(III) cen-
tre [1a,b]. Ruthenium complexes with other amide
nitrogen atom (2) of the amide linkage may be envis-
aged. Participation of the pyridyl nitrogen, Nb, coupled
with chelate rings 1 or 2, would lead to a tridentate
mode of coordination for HL. HL may also act as a
ligands are also abundant [2,3], but these do not involve
bridging ligand. Additional coordination modes may be
the study of linkage isomerisation. In this paper, the
syntheses and characterisation of 2-(N-(2-pyridyl)-
envisaged when HL is deprotonated. Analogous chelate
rings to 1 and 2 have been reported for ruthenium
carbamoyl)pyridine (HL) and a complex, [Ru(HL)-
complexes with other amide ligands [2,3]; and in the
(PPh3)2Cl2] where HL exists as a zwitterion, are re-
present study type 2 is found for complexes containing
both neutral HL and its deprotonated form.
ported. Reactions of the complex with bidentate chelat-
ing ligands, leading to the substitution of two chlorides
and formation of mixed-ligand complexes of the type
1 *Corresponding author. Tel.: +91-265-79552.
2 *Corresponding author.
0277-5387/01/$ - see front matter © 2001 Elsevier Science Ltd. All rights reserved.
PII: S0277-5387(01)00706-9

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S. Dutta et al. / Polyhedron 20 (2001) 1815–1820
2. Experimental
2.1. Materials
bonate. The resulting white solid was filtered, washed
thoroughly with distilled water and crystallised from
aqueous methanol as colourless needles. Yield: 1.65 g
(67%), m.p. 110°C. Anal. Found C; 66.16; H, 4.28; N,
20.81. Calc. for C11H9N3O: C, 66.33; H, 4.52; N,
21.10%.
RuCl3·xH2O (Loba, India) was converted to
RuCl3·3H2O by repeated evaporation to dryness with
concentrated hydrochloric acid. Pyridine-2-carboxylic
acid (E-Merck, Germany), 2-aminopyridine (Sigma)
and triphenylphosphine (Loba, India) were used as
received. Acetonitrile was distilled over CaH2 before
performing electrochemical experiments and ethanol
was dried over fused CaO. All other chemicals were
obtained from commercial sources and were used as
received. Tetraethylammonium perchlorate [4] (TEAP)
and [Ru(PPh3)3Cl2] [5] were prepared as reported
before.
2.4. Syntheses of the complexes
Caution: Although no problems were encountered in
the present study, perchlorate salts are potentially ex-
plosive and should be handled in small quantities.
Dichlorobis-triphenylphosphine[2-(N-(2-pyridinium-2-
yl)-carbamoyl-N−)-pyridine]ruthenium(II)
[Ru(HL)-
(PPh3)2Cl2] (I). To a solution of HL (21 mg, 0.1 mmol)
in 15 ml dry ethanol, [Ru(PPh3)3Cl2] (0.1 g, 0.1 mmol)
was added. The resulting suspension was refluxed for 2
h with stirring. From the cold reaction mixture the deep
brown coloured microcrystalline product was isolated
by filtration, washed thoroughly with dry ethanol, and
dried over fused CaCl2. Yield: 66 mg (71%). Anal.
Found C; 62.87; H, 4.27; N, 4.65. Calc. for
C47H39Cl2N3OP2Ru: C, 63.01; H, 4.36; N, 4.69%.
[2 - (N - (2 - pyridyl)carbamoyl)pyridine]bis - triphenyl-
phosphine(2,2% - bipyridine)ruthenium(II) - perchlorate,
[Ru(L−)(bpy)(PPh3)2]ClO4 (II). To a solution of 2,2%-
bipyridine (bpy) (18 mg, 0.11 mmol) in 10 ml dry
ethanol, I (0.1 g, 0.11 mmol) and triethylamine (12 mg,
0.11 mmol) were added. The resulting suspension was
refluxed for 2 h. The resulting deep red coloured solu-
tion was filtered to reject any impurity and the solution
was subjected to distillation to obtain a concentrated
solution. Into this cold solution 5 ml saturated aqueous
sodium perchlorate solution was added. The red
coloured solid product was isolated by filtration,
washed thoroughly with distilled water, dried over
fused CaCl2. Yield: 95 mg (85%). Anal. Found C; 63.64;
H, 4.48; N, 6.21. Calc. for C57H46ClN5O5P2Ru: C,
63.42; H, 4.26; N, 6.49%.
2.2. Physical measurements
Microanalysis (C, H, N) was performed using a
Perkin–Elmer 240 C elemental analyser. IR spectra
were obtained on a Perkin–Elmer 783 spectrophotome-
ter. Electronic spectra were recorded on a Shimadzu
240-UV–Vis spectrophotometer. Magnetic susceptibili-
ties were measured employing a PAR 155 vibrating
1
sample magnetometer. The H NMR spectra were ob-
tained with a 300 MHz Varian Fourier-transform spec-
trometer, using TMS as an internal standard. The
positive ion electrospray mass spectra were recorded on
a Micromass Quattro II triple quadruple mass spec-
trometer (assignments are based on the 102Ru isotope).
The FAB mass spectrum of LH was recorded on a
JOEL SX 102/DD 6000 mass spectrometer. Electro-
chemical measurements were made using a 174 polaro-
graphic analyser, a universal programmer, an X–Y
recorder, a platinum working electrode, a platinum wire
auxiliary electrode and Ag ꢀ AgNO3 reference electrode.
All electrochemical measurements were performed un-
der a nitrogen atmosphere. Ferrocene was used as an
internal standard and all potentials are quoted versus
the ferrocene/ferrocenium couple. The supporting elec-
trolyte used was TEAP.
The complexes [2-(N-(2-pyridyl)carbamoyl)pyridine]-
bis-triphenylphosphine(1,10-phenanthroline)ruthenium-
(II)-perchlorate,
[Ru(L−)(phen)(PPh3)2]ClO4
(III).
[2-(N-(2-pyridyl)carbamoyl)pyridine]bis-triphenylphos-
phine(1,2 - diaminoethane)ruthenium(II) - perchlorate,
[Ru(L−)(en)(PPh3)2]ClO4 (IV) and [2-(N-(2-pyridyl)-
carbamoyl)pyridine]bis-triphenylphosphine(2-(2-amino-
2.3. Ligand synthesis
2-(N-(2-Pyridyl)carbamoyl)pyridine (HL). Into a so-
lution of pyridine-2-carboxylic acid (1.54 g, 12.5 mmol)
in 5 ml pyridine, 2-aminopyridine (1.18 g, 12.5 mmol)
was added and warmed with stirring for 15 min. Into
the resulting solution triphenylphosphite (3.3 ml, 12.5
mmol) was added and the mixture was stirred at 110°C
for 4 h. The cold reaction mixture was washed with 100
ml distilled water. The resulting light brown oil was
taken in 50 ml dichloromethane and was extracted in
150 ml 1:1 (v/v) aqueous hydrochloric acid. The acidic
aqueous extract was neutralised by solid sodium bicar-
ethylpyridine)ruthenium(II)-perchlorate,
[Ru(L−)-
(amepy)(PPh3)2]ClO4 (V) were prepared by a method
similar to that used for the preparation of II, using an
equivalent amount of 1,10-phenanthroline (phen), 1,2-
diaminoethane (en) and 2-(2-aminoethyl)pyridine
(amepy), respectively, instead of 2,2%-bipyridine. Yields:
104 mg, (91%) for III, 90 mg, (88%) for IV, and 102
mg, (94%) for V. Anal. Found for III: C; 64.20; H, 4.24;
N, 6.13. Calc. for C59H46ClN5O5P2Ru: C, 64.16; H,
4.17; N, 6.34%; for IV: C; 59.73; H, 4.41; N, 6.87. Calc.

S. Dutta et al. / Polyhedron 20 (2001) 1815–1820
1817
for C49H46ClN5O5P2Ru: C, 59.84; H, 4.68; N, 7.12%;
for V: C; 61.87; H, 4.68; N, 6.32. Calc. for
C54H48ClN5O5P2Ru: C, 62.04; H, 4.60; N, 6.70%.
8.38 (d, 1H, J=4.56, H3), 8.30 (d, 1H, J=7.33, H3%),
7.95 (t, 1H, J=4.60, H4), 7.89 (t, 1H, J=4.58, H5),
7.51 (t, 1H, J=7.38, H5%) and 7.09 (1H, t, J=7.27,
H4%).
2.5. X-ray crystallography
3.2. Syntheses and characterisation of the complexes
Intensity data for a colourless prism (0.20×0.20×
0.40 mm3) were collected at 293 K on a Rigaku AFC7R
diffractometer employing Mo Ka radiation (u=
The reaction of [Ru(PPh3)3Cl2] with an equimolar
quantity of HL in dry ethanol proceeds smoothly to
precipitate microcrystalline [Ru(HL)(PPh3)2Cl2] (I) in
reasonably good yield. Further reaction of I with neu-
tral chelating ligands, L%, in presence of an equivalent
amount of triethylamine and sodium perchlorate leads
to the formation of complexes of the form [Ru(L−
)(PPh3)2(L%)]ClO4, II–V (L%=bidentate chelating lig-
ands bpy, phen, en and amepy). When conducted in the
absence of triethylamine, the same products were ob-
tained but in lower yields. The complexes II–V were
isolated as perchlorate salts and the molar conductivity
data (Table 1) indicate that these are 1:1 electrolytes.
Microanalytical data (see Section 2) correspond to
the expected composition. Magnetic susceptibility mea-
surements show the complexes to be diamagnetic as
expected for ruthenium(II) (low spin d6, S=0). In the
IR spectrum of I the CO stretching is found at 1639
cm−1. The lowering of the CO stretching compared to
the free LH is typical for coordination of the amide-ni-
trogen in its deprotonated form [8]. A NH stretching
band for I appears as a broad band centred at 3442
cm−1, an indication of hydrogen bonding [9]. This
indicates that in the neutral complex I, HL exists as a
zwitterion with the deprotonation of the amide NH and
protonation of the pyridyl nitrogen. There is hydrogen
bond formation between the protonated pyridyl nitro-
gen and one of the coordinated chloride ligands. The
existence of the hydrogen bonding has been further
confirmed by the X-ray studies, discussed later. The
NH stretching band does not appear for II and III,
while for IV and V the band around 3311 cm−1 may be
attributed to NH of the coordinated primary amines.
The bands around 520, 690 and 740 cm−1 arise due to
coordinated triphenylphosphine [10,11]. Two intense
vibrations are observed at ca. 1091 and 622 cm−1, in
the IR spectra of II–V, which are ascribed to non-coor-
dinated perchlorate anions.
,
0.71073 A) and the ꢀ–2q scan technique such that qmax
was 30.5°. Corrections were made for Lorentz and
polarisation effects [6a] but not for absorption. Of the
13 345 reflections measured, 12 848 were unique (Rint
=
0.039) and of these, 6875 with I]3.0|(I) were used in
the subsequent analysis.
C47H39Cl2N3OP2Ru, M=895.8, monoclinic, P21/c,
,
a=15.786(2), b=19.848(2), c=13.085(2) A, i=
3
,
90.52(2)°, V=4099.6(8) A , Z=4, v (Mo Ka)=6.31
cm−1, F(000)=1832, 463 refined parameters, zmax
=
−3
,
0.75 e A
.
The structure was solved by heavy-atom methods
[6b] and refined by a full-matrix least-squares procedure
based on F [6a]. Non-hydrogen atoms were refined
employing anisotropic displacement parameters and C-
bound H atoms were included in the model at their
calculated positions; the NꢀH atom was located from a
difference map but included in a calculated position. A
weighting scheme of the form w=1/[|2(F)] was em-
ployed and at convergence, final R=0.040 and RW=
0.033. Fig. 3, showing the crystallographic numbering
scheme, was drawn with ORTEP at the 35% probability
level [6c].
3. Results and discussion
3.1. Synthesis and characterisation of the ligand
The ligand, HL, has been prepared by an analogous
procedure to that reported [7a] for the preparation of
picolinic acid amides with a slight modification in the
isolation of the product [7b]. The reaction between
pyridine-2-carboxylic acid and 2-aminopyridine pro-
ceeds smoothly in pyridine medium in presence of
triphenylphosphite. In the FAB mass spectrum the
maximum peak is observed at m/z 200, which corre-
sponds to the molecular ion (calculated molecular
weight 199). In the IR spectrum the NH and CO
stretching of the amide linkage are observed at 3347
The 1H NMR spectra of I–V were recorded in
CHCl3-d solution. In the spectrum of I, a signal due to
a NH proton is found at d 14.46, as a broad singlet.
This signal disappears on H2O-d2 exchange. The low
field proton signal supports the hydrogen bonding of
the pyridinium NH with one of the coordinated chlo-
ride ligands as indicated in the IR studies. The signal
1
and 1695 cm−1, respectively. The H NMR spectrum
(CHCl3-d) shows a singlet at l 10.56, which disappears
upon the addition of H2O-d2 and is thus, assigned to
the NH proton of the amide. In the aromatic region
eight resonances are found to integrate to eight pro-
tons. The signals in the aromatic region are assigned as:
l 8.65 (d, 1H, J=4.56, H6), 8.43 (d, 1H, J=7.30, H6%),
1
due to the NH proton does not appear in the H NMR
spectra of the other complexes, II–V, thereby confirm-
ing deprotonation of the ligand. From the above, it can

1818
S. Dutta et al. / Polyhedron 20 (2001) 1815–1820
Table 1
Characterisation data for I–V
Complex
Electronic spectral data a umax (nm)
Molar conductivity data c LM
Cyclic voltammetric data d
b
(m (dm3 mol−1 cm−1
)
(W−1 dm3 mol−1 cm2)
E0298, V (DEp, mV)
RuII/III
RuIII/IV
I
479(2299.8),308(10696.5)e, 274(28590.7),230(31760.6)
436(6865.8),293(30773.7), 230(36622.6)
437(8493.4),266(41011.6), 231(52173.3)
–
86
95
115
114
0.44(60)
0.40(07)
0.42(70)
0.59(70)
0.76(60)
0.98(60)
0.88(70)
0.93(70)
0.88(70)
-
II
III
IV
V
464(2421.3),401(331706), 258(21968.4),231(37480.9)
386(5861.6),312(9661.4)e, 254(2453408)e,230(40167.9)
a In dichloromethane solution
b Extinction coefficient
c In acetonitrile solution
d Conditions: solvent, acetonitrile; supporting electrolyte, tetraethylammonium perchlorate; working electrode, platinum; reference electrode,
Ag ꢀ Ag+; E2o98=0.5(Epa+Epc); DEp=Epa−Epc
.
e Shoulder
be concluded that, L− coordinates to ruthenium(II)
centre forming a chelate ring of type 2 in complexes
II–V. The aromatic region of the H NMR spectra of
3.4. Electrochemical properties
1
The electrochemical properties of I were studied in
dichloromethane solution (0.1 M TEAP) and those for
II–V were studied in acetonitrile solution (0.1 M
TEAP) by cyclicvoltammetry. The voltammetric data
are collected in Table 1 and a selected voltammogram is
shown in Fig. 2. Complexes I–IV show two reversible
responses in the potential range 0.35–1.0 V. The first
response is assigned to the ruthenium(II)/rutheniu-
m(III) oxidation and the second is due to the rutheniu-
all complexes are quite complicated owing to significant
overlap of the signals due to both HL, L−, L% and
triphenylphosphine ligands.
The electrospray mass spectra of two representative
complexes, III and V were recorded. The peaks ob-
served at m/z 1104.2 for III and at m/z 1046.2 for V
correspond to the molecular ions of the corresponding
complexes; calculated molecular weight: 1103.6 for III
and 1045.6 for V.
m(III)/ruthenium(IV)
oxidation.
For
all
the
voltammetric responses, the DEp values lie within the
range 60−70 mV, which do not change with changes
in the scan rate. The ipa/ipc (ipa=anodic peak current
3.3. Electronic spectra
Electronic spectra have been recorded in
dichloromethane solution. Spectral data are collected in
Table 1 and a representative spectrum is shown in Fig.
1. All complexes display intense absorption in the visi-
ble region. On the basis of the magnitudes of the
extinction coefficients, these bands are assigned to the
t62“p* metal to ligand charge-transfer (MLCT) transi-
tions [11]. For I two absorptions are found at 308 and
479 nm. The band at 308 nm disappears after conver-
sion of I into the other complexes, while the band at
479 nm remains for II–IV. For IV, a new band appears
at 401 nm and for V two new bands appear at 312 and
386 nm. Two intense absorptions at ca. 266 and 230
nm, which also appear in the spectrum of HL due to
intraligand transitions, appear in the UV region of the
spectra of all the complexes; for V the band at 254 nm
appears as a shoulder. In the complexes the intraligand
bands are found to appear with a minor shift in the
position compared to those for HL.
Fig. 1. Representative UV–Vis spectrum for III in dichloromethane.

S. Dutta et al. / Polyhedron 20 (2001) 1815–1820
1819
tion potentials for the substituted complexes II–V can
be attributed to the following reasons: (i) in all the
complexes the coordination from the negatively
charged nitrogen atom of the amide linkage, which is a
strong s-donor, increases the electron density over the
ruthenium(II) centres; (ii) in II and III there is substitu-
tion of the chloride ligands of I by the p-accepting
diimine ligands; (iii) all the complexes II–V have one
unit positive charge; and (iv) the higher molar conduc-
tance values for IV and V indicate that they are more
ionic i.e. the formal positive charge over these com-
plexes are greater compared to the same over II and III.
3.5. Crystal structure of I
Fig. 2. Representative voltammogram for III in acetonitrile (0.1 M
TEAP); scan rete 100 mV s−1
.
The molecular structure of I is illustrated in Fig. 3
and selected interatomic parameters are collected in
Table 2. The structure confirms the spectroscopic re-
sults obtained for I, i.e. type 2 coorindation, is also
found in the solid state. The transfer of the amide-pro-
ton to a pyridine-nitrogen retains the electrical neutral-
ity of the complex so that coordinated LH functions as
a zwitterion. The ruthenium atom exists in a distorted
octahedral geometry with a Cl2N2P2 donor set. The
maximum deviation from the ideal geometry is mani-
fested in the N(1)ꢀRuꢀN(8) chelate angle of 77.89(9)°.
,
The five-membered chelate ligand is planar to 0.067 A
but there is some buckling in this ring, notably about
the amide-nitrogen atom as seen in the RuꢀN8ꢀC7ꢀC6
torsion angle of 13.1(3)°. The dihedral angle between
the pyridine rings is calculated to be 29.5° suggesting
that there is no extensive delocalisation of p-electron
density over LH. This is further borne out by the
geometric parameters characterising the backbone of
Table 2
,
Selected bond lengths (A) and angles (°) for I
Bond lengths
RuꢀCl(1)
RuꢀP(1)
RuꢀN(1)
C(7)ꢀO(7)
N(1)ꢀC(6)
N(8)ꢀC(9)
N(10)ꢀC(11)
2.4503(9)
2.3804(8)
2.067(2)
1.232(4)
1.337(4)
1.362(4)
1.353(4)
RuꢀCl(2)
RuꢀP(2)
RuꢀN(8)
N(1)ꢀC(2)
N(8)ꢀC(7)
N(10)ꢀC(9)
2.4197(9)
2.3708(8)
2.152(2)
1.344(4)
1.375(4)
1.358(4)
Fig. 3. An ORTEP representation of I showing the atomic numbering
scheme.
and ipc=cathodic peak current) ratio is close to 1.0, as
expected for reversible response.
Bond angles
Cl(1)ꢀRuꢀCl(2)
Cl(1)ꢀRuꢀP(2)
Cl(1)ꢀRuꢀN(8)
Cl(2)ꢀRuꢀP(2)
Cl(2)ꢀRuꢀN(8)
P(1)ꢀRuꢀN(1)
P(2)ꢀRuꢀN(1)
N(1)ꢀRuꢀN(8)
RuꢀN(1)ꢀC(6)
RuꢀN(8)ꢀC(7)
C(7)ꢀC(8)ꢀC(9)
90.34(3)
86.39(3)
100.40(6)
88.00(3)
169.19(6)
90.23(7)
93.21(7)
77.89(9)
116.3(2)
113.5(2)
116.0(2)
Cl(1)ꢀRuꢀP(1)
Cl(1)ꢀRuꢀN(1)
Cl(2)ꢀRuꢀP(1)
Cl(2)ꢀRuꢀN(1)
P(1)ꢀRuꢀP(2)
P(1)ꢀRuꢀN(8)
P(2)ꢀRuꢀN(8)
RuꢀN(1)ꢀC(2)
C(2)ꢀN(1)ꢀC(6)
RuꢀN(8)ꢀC(9)
90.21(3)
178.24(6)
90.48(3)
91.36(7)
176.27(3)
90.69(7)
91.44(7)
126.6(2)
117.1(2)
130.3(2)
For I the responses due to Ru(II)/Ru(III) and
Ru(III)/Ru(IV) couples appear at 0.44 and 0.98 V,
respectively. In the complexes II and III the same
oxidation couples appear at a lower potential value
compared to I, whereas in case of complex IV they
appear at a more positive potential. For complex V, the
response due to Ru(II)/Ru(III) couple appears at a
higher positive potential compared to I, while the
Ru(III)/Ru(IV) oxidation couple does not appear
within the solvent window. The difference in the oxida-

1820
S. Dutta et al. / Polyhedron 20 (2001) 1815–1820
the ligand (Table 2). The RuꢀN(amidato) distance of
the Head, Department of chemistry, M.S. University of
Baroda for providing laboratory facility.
,
2.152(2) A is [4a,5b] longer, as expected, than the
,
RuꢀN(pyridine) distance of 2.067(2) A and both fall in
the ranges expected for such interactions[2]. A key
feature of the molecular structure is the presence of a
short intramolecular NꢀH···Cl interaction that provides
additional stability to the ligand donor set.
References
[1] (a) Y. Ilan, H. Taube, Inorg. Chem. 22 (1983) 1655. (b) Y. Ilan,
M. Kapon, Inorg. Chem. 25 (1986) 2350. (c) D.P. Fairlie, H.
Taube, Inorg. Chem. 24 (1985) 3199. (d) D.P. Fairlie, Y. Ilan, H.
Taube, Inorg. Chem. 36 (1997) 1029.
[2] S.M. Redmore, C.E.F. Rickard, S.J. Webb, L.J. Wright, Inorg.
Chem. 36 (1997) 4743.
The NꢀH atom was located in the X-ray study and is
,
separated from Cl(1) by 2.17 A so that Cl(1)···N(10) is
,
3.016(3) A. The participation of the Cl(1) atom in this
contact has the result that its distance to the ruthenium
centre has elongated significantly, i.e. by approximately
[3] (a) P.-H. Co; T.-Y. Chen; J. Zhu; K.-F. Cheng; S.-M. Peng,
C.-M. Che, J. Chem. Soc., Dalton Trans. (1995) 2215 (b) P.-M.
Chan; W.-Y. Yu; C.-M. Che, K.-K. Cheung, J. Chem. Soc.,
Dalton Trans. (1998) 3183.
[4] D.T. Sawyer, J.L. Roberts Jr., Experimental Electrochemistry
for Chemists, Wiley, New York, 1974 (pp. 167–215).
[5] T.A. Stephenson, G. Wilkinson, J. Inorg. Nucl. Chem. 28 (1966)
945.
,
0.03 A, compared to the RuꢀCl(2) distance (Table 2).
The closest intermolecular contact involving non-H
i
,
atoms of 3.290(4) A between the O(7) and C(116)
,
atoms corresponds to an O···H separation of 2.74 A;
symmetry operation i: x, 0.5−y, −0.5+z.
[6] (a) Programs used for X-ray analysis: TEXSAN, Structure Analy-
sis Package, Molecular Structure Corporation, TX, 1992. (b)
P.T. Beurskens, G. Admiraal, G. Beurskens, W.P. Bosman, S.
Garc´ıa-Granda, J.M.M. Smits and C. Smykalla, The DIRDIF
program system, Technical Report of the Crystallography Labo-
ratory, University of Nijmegen, 1992. (c) C.K. Johnson, ORTEP
II, Report ORNL-5136, Oak Ridge National Laboratory, Oak
Ridge, TN, 1976.
[7] (a) D.J. Barnes, R.L. Chapman, R.S. Vagg, E.C. Watton., J.
Chem. Engng Data, 23 (1978) 349. (b) S. Dutta, S. Pal, P.K.
Bhattacharya, Polyhedron, 18 (1999) 2157.
[8] K. Nakamoto, Infrared and Raman Spectra of Inorganic and
Co-ordination Compounds, 3rd edition, Wiley, New York,
1978.
4. Supplementary material
Crystallographic data for the structural analysis has
been deposited at the Cambridge Crystallographic Data
Centre, CCDC No. 149895. Copies of the information
may be obtained free of charge from The Director,
CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK
(fax: +44-1223-336033; e-mail: deposit@ccdc.cam.
ac.uk or www:http://www.ccdc.cam.ac.uk).
Acknowledgements
[9] P. Ghosh, Polyhedron 16 (1997) 1343 (and refernece therein).
[10] P.K. Sinha, J. Chakravarty, S. Bhattacharya, Polyhedron 16
(1997) 81.
The authors P.K.B and S.D are thankful to DST,
Government of India, for the financial assistance and
[11] J. Chakravarty, S. Bhattacharya, Polyhedron 15 (1996) 257.
.