Synthesis, characterisation and thermal studies of ruthenium(II) carbonyl complexes of functionalised tripodal phosphine chalcogen donor ligands, [CH3C(CH2P(X)Ph2)3], where X = Se, S, O

Article abstract of DOI:10.1016/j.saa.2008.09.018

The polymeric ruthenium(II) carbonyl complex, [Ru(CO)₂Cl₂]_n reacts with 1,1,1-tris-(diphenylphosphinomethyl)ethane trichalcogenide ligands, [CH₃C(CH₂P(X)Ph₂)₃], where X = Se(a),

Full text of DOI:10.1016/j.saa.2008.09.018

Spectrochimica Acta Part A 72 (2009) 339–342
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Spectrochimica Acta Part A: Molecular and
Biomolecular Spectroscopy
journal homepage: www.elsevier.com/locate/saa
Synthesis, characterisation and thermal studies of ruthenium(II) carbonyl
complexes of functionalised tripodal phosphine chalcogen donor ligands,
[CH3C(CH2P(X)Ph2)3], where X = Se, S, O
Biswajit Deb, Bhaskar Jyoti Sarmah, Bibek Jyoti Borah, Dipak Kumar Dutta∗
Materials Science Division, North-East Institute of Science and Technology (CSIR), Jorhat 785 006, Assam, India
a r t i c l e i n f o
a b s t r a c t
Article history:
The polymeric ruthenium(II) carbonyl complex, [Ru(CO)2Cl2]n reacts with 1,1,1-tris-(diphenyl-
phosphinomethyl)ethane trichalcogenide ligands, [CH3C(CH2P(X)Ph2)3], where X = Se(a), S(b) and
O(c) in 1:1 (metal:ligand) molar ratio to afford hexa-coordinated complexes of the type ␩2-(X,X)-
[Ru(CO)2Cl2P3X3] (1a–c). The complexes 1a–c exhibit two equally intense ꢀ(CO) bands in the range
1979–2060 cm−1 indicating cis-disposition of the two terminal carbonyl groups. The values of ꢀ(CO)
frequencies containing different ligands, in general, follow the order: P3O3 > P3S3 > P3Se3 which may be
explained in terms of ‘Soft–Hard’ (Ru(II)–O) and ‘Soft–Soft’ (Ru(II)–S/Se) interactions. The complexes have
been characterized by elemental analyses, mass, 1H, 31 P, 77Se and 13 C NMR spectroscopy. The thermal
stability of the complexes has also been studied.
Received 10 August 2008
Received in revised form
25 September 2008
Accepted 28 September 2008
Keywords:
Ruthenium(II)
Carbonyl complexes
Functionalized phosphine
Tripodal
© 2008 Elsevier B.V. All rights reserved.
Phosphine chalcogen donor
Thermal studies
1. Introduction
chalcogen donor ligands. In this paper, we report synthesis, spec-
troscopic characterization and thermal studies of ruthenium(II)
carbonyl complexes of the type [Ru(CO)2Cl2P3X3] (1) [X = Se(a),
S(b) and O(c)] with an ultimate aim to use them as catalyst
for selective organic transformations. The ꢀ(CO) frequencies of
the complexes are discussed in terms of the soft/hard acid/base
concept.
The chemistry of transition metal complexes with the
tripodal tridentate phosphine ligand 1,1,1-tris(diphenylph-
osphinomethyl)ethane (P3) has been developed in the last two
decades [1]. In particular, complexes containing [M(P3)] or
[M(CO)x(P3)] (x = 1, 2 or 3) fragment (M = Re, Ru, Rh or Ir) are
studied extensively because of their reactivity, structural nov-
elty and catalytic activities [2–6]. However, organophosphorus
ligands such as tertiary phosphineoxides, sulphides, or selenides
bearing O, S, or Se donor atoms have got much attention due
to their coordination chemistry, extractive metallurgy, catalytic
properties, and structural chemistry [7,8]. Metal complexes of
mono- and di-tertiary phosphine chalcogenides particularly
oxides, sulfides and selenides are reported [9–14]; but stud-
ies with poly-tertiary phosphine chalcogenides are only a few
[15–19]. The multidentate tertiary phosphine chalcogen deriva-
tives provide an interesting set of ligands whose coordination
chemistry is rich from the structural aspect, bonding interaction
and spectroscopic point of view. But, to our knowledge, there is
no report of ruthenium(II) carbonyl complexes containing P3X3 as
2. Experimental
All solvents were distilled under N2 prior to use. Tetrahydrofuran
(THF) was dried using standard literature procedure. RuCl3·xH2O
was purchased from M/S Arrora Matthey Ltd., Kolkota, India.
[CH3C(CH2PPh2)3], elemental sulfur and selenium were purchased
from M/S Aldrich, USA and used without further purification. H2O2
was obtained from Ranbaxy, New Delhi, India and estimated before
use.
Elemental analyses were performed on a Perkin-Elmer 2400 ele-
mental analyzer. IR spectra (4000–400 cm−1) were recorded on KBr
discs in a Perkin-Elmer system 2000 FT-IR spectrophotometer. The
1H, 13C and 31P NMR spectra were recorded at room temperature
in CDCl3 solution on a Bruker DPX-300 Spectrometer and chemi-
cal shifts are reported relative to SiMe4 and 85% H3PO3 as internal
and external standards respectively. Selenium-77 NMR (51.52 MHz)
spectra were recorded in CDCl3 solution on a Jeol Delta 270MHz
Spectrometer at room temperature. Mass spectra of the complexes
∗
Corresponding author. Tel.: +91 376 2370 081; fax: +91 376 2370 011.
E-mail address: dipakkrdutta@yahoo.com (D.K. Dutta).
1386-1425/$ – see front matter © 2008 Elsevier B.V. All rights reserved.
doi:10.1016/j.saa.2008.09.018

340
B. Deb et al. / Spectrochimica Acta Part A 72 (2009) 339–342
Scheme 1. Syntheses of the complexes 1a–c.
were recorded on ESQUIRE 3000 Mass Spectrometer. Thermal anal-
yses of the complexes were carried out using a thermal analyzer
(TA instrument, Model STD 2960 simultaneous DTA–TGA) under
N2 atmosphere with a heating rate of 10 ◦C/min.
0.218 mmol (147 mg) of ligand c in dichloromethane. The result-
ing mixture was refluxed for 5 h and the solvent was removed
under reduced pressure to get a solid product, which was washed
with diethyl ether and finally recrystallised from dichloromethane
solution to generate a greenish yellow solid compound. Yield:
78%.
2.1. Syntheses of the ligands, [CH3C(CH2P(X)Ph2)3], where (X = Se,
S, O)
3. Results and discussion
The ligands [CH3C(CH2P(Se)Ph2)3](a), [CH3C(CH2P(S)Ph2)3](b)
and [CH3C(CH2P(O)Ph2)3](c) were synthesized by slightly mod-
ifying standard literature methods [16,19–21]. The ligand ‘a’
was prepared by refluxing a solution of [CH3C(CH2PPh2)3] (1 g,
1.6 mmol) in toluene with the appropriate quantity of black sele-
nium (383 mg, 4.85 mmol). After the selenium has dissolved, the
solvent was removed under vacuum and the isolated solids were
recrystallised from dichloromethane and hexane [21]. The ligand
‘b’ was prepared in a similar manner by stirring the solution of
[CH3C(CH2PPh2)3] (1 g, 1.6 mmol) in toluene with a threefold excess
elemental sulfur (155 mg, 4.85 mmol) at room temperature [19,20].
The ligand ‘c’ was prepared by oxidation of [CH3C(CH2PPh2)3] (1.5 g,
2.4 mmol) with excess H2O2 in acetone [16,19].
3.1. Preparative considerations
The polymeric complex [Ru(CO)2Cl2]n reacts with equimo-
lar quantity of the ligands (a–c) by cleavage of the chloro
bridge to produce hexa-coordinated ␩2-X,X bonded complexes
[Ru(CO)2Cl2P3X3] (Scheme 1). All the complexes 1a–c thus pre-
pared are microcrystalline solids, stable in air and moisture.
Elemental analyses of the complexes 1a–c were determined and
the results matched well with the calculated values of molecular
composition [Ru(CO)2Cl2P3X3] (Table 1).
3.2. IR and NMR (1H, 31P, 13 C and 77Se) spectra
2.2. Synthesis of the starting complex, [Ru(CO)2Cl2]n
The IR spectrum (Table 2) of the complex 1a shows two equally
intense ꢀ(CO) bands in the regions 2044 and 1979 cm−1, indicat-
ing the presence of two terminal CO groups cis to one another
[10,12]. ꢀ(P–Se) bands at around 546, 539 and 533 cm−1 are about
2, 9 and 15 cm−1 lower than that in the corresponding free ligand
[ꢀ(P–Se) = 548 cm−1], suggesting two of the three P–Se groups are
The starting complex [Ru(CO)2Cl2]n was prepared by passing CO
through a refluxing solution of RuCl3·3H2O in ethanol for about 24 h
[22–25].
2.3. Synthesis of the complex, [Ru(CO)2Cl2(P3Se3)] (1a)
1
bonded through chalcogen donors. The 31P{ H} NMR spectra of
the complex 1a show two singlets centred at ı = 19.3 and 22.9 ppm
(intensity ratio 2:1) for three pentavalent P-atoms respectively,
exhibiting an up field shift compared to the free ligand (ı = 23.1).
The 1H NMR spectra (Table 2) of 1a show three multiplet resonances
in the ranges ı 7.07–7.26, ı 7.39–7.64 and ı 7.93–8.2 ppm which is
attributable to the three non-equivalent phenylic protons. Each of
the methylene protons appear separately as doublet centered at
4.02 and 4.42 ppm due to coupling with one phosphorus atom and
the other hydrogen which are matching well with the related com-
plexes of similar type of bidentate ligands reported by Dutta et al.
0.218 mmol (50 mg) of [Ru(CO)2Cl2]n was dissolved in THF
(10 cm3), to that 0.218 mmol (188 mg) of ligand a in 10 cm3 THF
was added dropwise by using a syringe. The reaction mixture was
refluxed for 2 h. The solvent was evaporated under reduced pres-
sure to get a solid product which was washed with diethyl ether and
finally recrystallised from dichloromethane solution to generate a
brown solid compound. Yield: 84%.
2.4. Synthesis of the complex, [Ru(CO)2Cl2(P3S3)] (1b)
[Ru(CO)2Cl2]n (0.439 mmol, 100 mg) was dissolved in methanol
(10 cm3) and the ligand ‘b’ (0.439 mmol, 317 mg) was dissolved in
dichloromethane (10 cm3). Both the solutions were mixed together
and refluxed for 3 h. The solvent was removed and the solid residue
was washed with diethyl ether. The resulting yellow compound was
recrystallised from dichloromethane/hexane to give the complex
‘1b’. Yield: 82%.
Table 1
Elemental analyses and mass spectrometric data of ligands and their complexes.
Compounds
Expected
molecular weight
Found (cald.) (%)
C
Mass (m/z)
H
a
b
c
1a
1b
1c
861.69
720.69
672.69
1089.69
948.69
900.69
56.93 (57.10)
67.79 (68.26)
72.91 (73.13)
46.89 (47.35)
54.12 (54.39)
57.06
4.35 (4.52)
5.21 (5.41)
5.38 (5.80)
861.5
719.8
673
2.5. Synthesis of the complex, [Ru(CO)2Cl2(P3O3)] (1c)
3.23 (3.58) 1089.1
4.03 (4.11)
4.52
(4.33)
949.4
674.1
695.8
The complex ‘1c’ was prepared by mixing
a solution of
(57.29)
0.218 mmol (50 mg) of [Ru(CO)2Cl2]n in THF (10 cm3) and

B. Deb et al. / Spectrochimica Acta Part A 72 (2009) 339–342
341
Table 2
Important IR (cm−1), 1H, 31 P and 77Se NMR (␦ in ppm) values of the ligands and their complexes.
Compounds
IR (cm−1
ꢀ(CO)]
–
)
31 P
77Se
1H NMR
CH3
ꢀ(P-X)
P = X
23.1(s)
P = Se
JP–Se (Hz)
CH2
C6H5
7.15–7.41(m)
a
548
−298(d)
715
0.59(s)
4.02(d)
8.0–8.06 (m)
–
–
625
611
35.5(s)
32.3(s)
0.64(s)
0.85(s)
0.60(s)
3.8(d)
6.98–7.40(m)
7.97–8.02(m)
b
c
1175
3.19(d)
7.27–7.50(m)
7.65–7.85(m)
1a
1b
1c
1979
2044
546
539
533
22.9(s)
19.3(s)
−295(d)
−265(d)
710
605
4.02(d)
4.42(d)
7.07–7.26(m)
7.39–7.64(m)
7.93–8.2(m)
1984
2059
624
606
41.3(s)
35.8(s)
0.68(s)
0.91(s)
3.76(d)
3.92(d)
7.03–7.48(m)
7.80–7.90(m)
7.96–8.13(m)
1988
2060
1174
1168
38.2(s)
32.7(s)
3.18(d)
3.27(d)
7.15–7.35(m)
7.45–7.61(m)
7.75–7.86(m)
s = singlet, d = doublet, m = multiplet.
indicated a marginal changes of 1 cm−1 suggesting the halide
[12] and Gonsalvi et al. [26]. The three methylene protons in the
chelate ligand do not seem to be equivalent which may be explained
by considering the fact that out of three P–Se donors, two of them
have coordinated to the metal center and the remaining one arm
is dangling [19]. This fact is well supported by its corresponding
substitution is very much unlikely. The 31P{ H} NMR spectra of
1
the complexes 1b and 1c show two singlets centred at ı = 35.8,
41.3 ppm, and 32.7, 38.2 ppm respectively for three pentavalent P-
atoms, which show a downfield shift compared to the free ligands
b (35.5 ppm) and c (32.3 ppm). The intensity ratio of the two sin-
glets from higher value to the lower value is found to be 2:1 in both
the complexes (1b and 1c). The occurrence of IR bands at around
546, 624 and 1174 cm−1 and their corresponding 31P NMR peak at
22.9, 35.8 and 32.7 ppm in the respective complexes 1a–c indicate
the presence of one dangling P–X (Scheme 1). The 1H NMR spec-
tra (Table 2) of the complexes 1b and 1c show the characteristic
resonances for the methylene and phenylic protons. Similar to the
complex 1a, the 13C NMR spectra of the complexes 1b and 1c also
consist of all characteristic signals for carbonyl and other carbons
(Table 3).
1
IR and 31P{ H} NMR data. In the 13C NMR spectra, only one weak
signal for the two carbonyl carbons is appeared as broad singlet
at ı 187.1 ppm. The phenyl and other carbons are found in their
respective range (Table 3).
Similar to 1a, the complexes 1b and 1c also exhibit two
intense ꢀ(CO) bands in the region 2060–1984 cm−1 respectively,
attributing the presence of two terminal CO groups cis to one
another. It is observed that the order of appearance of ꢀ(CO)
bands in respect of energy is 1a < 1b < 1c, which may be explained
in terms of ‘Soft–Hard’ [Ru(II)(Soft)–O(Hard)] and ‘Soft–Soft’
[Ru(II)(Soft)–S/Se(Soft)] interactions between the metal atom and
the chalcogen donors. ‘Se’ and ‘S’ in complexes 1a and 1b respec-
tively interact strongly with ‘Soft’ ruthenium(II) in contrast to
‘Hard’ oxygen (O) donor in complex 1c. Because of the ‘Soft–Soft’
interaction, the electron density increases on the central metal
atom which leads to donate more d␲-electrons to the antibond-
ing ␲* orbital of the CO [13,27,28] and consequently reduces the
CO bond order, which in turn lowers the ꢀ(CO) frequency. The
ꢀ(P–X) (X = S, O) bands in the complexes 1b and 1c occur at 624,
606 [ꢀ(P–S)] and 1174, 1168 cm−1 [ꢀ(P–O)] respectively are lower
than their corresponding free ligands [ꢀ(P–S) = 625, 611 cm−1 and
ꢀ(P–O) = 1175 cm−1]. The appearance of ꢀ(P–X) in 1a–c at relatively
lower stretching values on KBr disk compared to those reported
metal complexes [9–13] has prompted us to record the IR spectra in
nujol mull for confirmation whether any substitution by bromide
(from KBr) has occurred. The results of ꢀ(CO) and ꢀ(P–X) bands
The 77Se NMR spectra of the complex 1a exhibit two
doublets centered at −295 ppm (JP–Se = 710 Hz) and −265 ppm
(JP–Se = 605 Hz) for three P–Se groups which show a downfield
shift compared to the free ligand {ı = −298 ppm (d, JP–Se = 715 Hz)}.
The significant different chemical shifts as well as the coupling
constants of the complex 1a from that of the free ligand, and
the observed peak intensity of 1a reveal that two of the P–Se
groups have undergone chelate formation leaving one arm dan-
gling. Although no such evidence is available for the compounds
1
containing P3S3 and P3O3, the similar 31P { H} NMR spectra and
the infrared spectral evidence [ꢀ(P–X), X = S, O] are sufficient to
confirm coordination of S and O in the compounds 1b and 1c
respectively.
3.3. Electrospray mass spectrometry
Table 3
Important 13 C NMR data of the ligands and their complexes (␦ in ppm).
The solubility of the complexes 1a–c was investigated in chlo-
roform and their m/z values were analyzed by considering both
positive and negative mode of ion polarity. Poor ionization was
apparent for the complex 1c with [c+Na]+ and [c+H]+ being the
main features in the resulting spectra. Better quality spectra were
obtained for the complexes 1a,b which showed peaks consistent
with expected molecular ion peak. A cluster of peaks of low inten-
sity centered at m/z = 1089.1 (1a) and 949.4 (1b) are assigned to
[Ru(CO)2Cl2P3Se3]+ and [Ru(CO)2Cl2P3S3]+ respectively (Table 1).
Compounds
CH3
CH2–P = X
C
C6H5
CO
a
b
c
1a
1b
1c
26.1(q)
26.4(q)
29.1(q)
26.2(q)
25.9(q)
28.7(q)
40.9(dt)
41.8(dt)
41.1(dt)
41.2(dt)
41.9(dt)
41.8(dt)
42.9(q)
42.3(q)
39.7(q)
42.3(q)
41.5(q)
38.8(q)
128.38–132.78(m)
128.33–134.23(m)
128.57–134.51(m)
128.83–132.30(m)
128.92–134.32(m)
128.98–134.68(m)
–
–
–
187.1
186.5
186.2
dt = doublet of triplet, q = quartet.

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B. Deb et al. / Spectrochimica Acta Part A 72 (2009) 339–342
3.4. Thermal analysis
cations as efficient catalysts in organic transformations under
considerably higher temperature environment.
The thermal behaviour of the new compounds was investi-
gated using simultaneous differential thermoanalysis (DTA) and
thermogravimetry (TG) in a nitrogen atmosphere. The complex
1a decomposes in two steps, the first step observed in the tem-
perature range 210–255 ◦C with a total mass loss of 5.2% which
can be assigned to the removal of two CO groups. Similarly, the
complex 1b also undergoes decomposition by the loss of two CO
groups in the temperature range 130–180 ◦C with a mass loss
of 5.8%. These results can be corroborated by a similar type of
complexes reported by Soliman et al. [29]. Further decomposi-
tion of the complexes 1a and 1b proceeds in multiple stages that
extend in the temperature ranges at 250–460 ◦C and 280–520 ◦C
respectively. The observed mass loss notified by TG curve fits in
each case perfectly as the loss of the fragmented organic ligand,
whereby the corresponding DTA curve shows a strong endother-
mic effect. The complex 1c, on the other hand, shows mass loss
at the temperature of about 70 ◦C may be due to the elimina-
tion of solvent (THF) molecule from the matrix. On increasing
the temperature up to about 300 ◦C, there is a total mass loss
of about 10.0% in the temperature ranges of 100–130 ◦C and
240–300 ◦C, which may be due to the removal of moisture and
CO groups respectively from the complex moiety. The presence
of THF and water molecules in the complex matrix as indicated
by TG curve is also partially supported by elemental analysis.
On further increasing the temperature, there are at least three
stages of mass losses in the range of 300–500 ◦C corresponding
to decomposition of organic ligands from the matrix indicated
by three endothermic events in the DTA curve. The observed
mass loss may be due to the elimination of molecules like HCl,
CO, H2O, etc. formed from decomposed moieties of the metal
complex.
Acknowledgements
The authors are grateful to Dr. P.G. Rao, Director, North-East
Institute of Science and Technology (CSIR), Jorhat, Assam, India,
for his kind permission to publish the work. Thanks are also to
DST, New Delhi for a financial support (Grant: SR/S1/IC-05/2006).
The authors B. Deb (JRF), B.J. Borah (JRF) and B.J. Sarmah (SRF) are
grateful to CSIR for providing the fellowships.
References
[1] H.A. Mayer, W.C. Kaska, Chem. Rev. 94 (1994) 1239.
[2] W.O. Siegl, S.J. Lapporte, J.P. Collman, Inorg. Chem. 12 (1973) 3.
[3] T. Suzuki, K. Isobe, K. Kashiwabara, J. Fujita, S. Kaizaki, Dalton Trans. (1996)
3779.
[4] L.F. Rhodes, C. Sorato, L.M. Venanzi, F. Bachechi, Inorg. Chem. 27 (1988) 604.
[5] R.L. Geerts, J.C. Huffmann, G.K. Caulton, Inorg. Chem. 25 (1986) 590.
[6] W.O. Siegel, S.J. Lapporte, J.P. Collmann, Inorg. Chem. 10 (1971) 2158.
[7] T.S. Lobana, R. Verma, A. Singh, M. Shikha, A. Castineiras, Polyhedron 21 (2002)
205.
[8] T.S. Lobana, Prog. Inorg. Chem. 37 (1989) 495.
[9] D.K. Dutta, J.D. Woollins, A.M.Z. Slawin, D. Konwar, M. Sharma, P. Bhatacharyya,
S.M. Aucott, J. Organomet. Chem. 691 (2006) 1229.
[10] P. Chutia, M. Sharma, P. Das, N. Kumari, J.D. Woollins, A.M.Z. Slawin, D.K. Dutta,
Polyhedron 22 (2003) 2725.
[11] P. Das, D. Konwar, P. Sengupta, D.K. Dutta, Trans. Met. Chem. 25 (2000) 426.
[12] D.K. Dutta, P. Chutia, J.D. Woollins, A.M.Z. Slawin, Inorg. Chim. Acta 359 (2006)
877.
[13] P. Chutia, N. Kumari, M. Sharma, J.D. Woollins, A.M.Z. Slawin, D.K. Dutta, Poly-
hedron 23 (2004) 1657.
[14] S.N. Arbuzova, N.K. Gusarova, M.V. Bogdanoma, I.A. Ushakov, A.G. Malkina, B.A.
Trofimov, Mendeleev Commun. 17 (2007) 325.
[15] M. Valderrama, R. Contreras, V. Aranciba, P. Munaj, D. Boys, M.P. Lamata, F.
Viguri, D. Carmona, F.J. Lahoj, J.A. Lopez, L.A. Oro, J. Organomet. Chem. 545–546
(1997) 507.
[16] A.M.J. Lees, A.W.G. Platt, Polyhedron 24 (2005) 427.
[17] P.A.W. Dean, M.K. Hughes, Can. J. Chem. 58 (1980) 180.
[18] J. Browning, K.R. Dixon, N.J. Meanwell, F. Wang, J. Organomet. Chem. 460 (1993)
117.
4. Conclusions
[19] K. Heinze, G. Huttner, L. Zsolnai, Chem. Ber. 130 (1997) 1393.
[20] A.M. Bond, R. Colton, P. Panagiotidou, Organometallics 7 (1988) 1763.
[21] R. Colton, T. Whyte, Aust. J. Chem. 44 (1991) 525.
[22] M.L. Berch, A. Davison, J. Inorg. Nucl. Chem. 35 (1973) 3763.
[23] R. Colton, R.H. Farthing, Aust. J. Chem. 20 (1967) 1283.
[24] R.J. Irving, J. Chem. Soc. (1956) 2879.
[25] M.J. Cleare, W.P. Griffith, J. Chem. Soc. A (1969) 372.
[26] L. Gonsalvi, H. Adams, G.J. Sunley, E. Ditzel, A. Haynes, J. Am. Chem. Soc. 124
(2002) 13597.
[27] M. Sharma, N. Kumari, P. Das, P. Chutia, D.K. Dutta, J. Mol. Catal. A: Chem. 188
(2002) 25.
[28] T.S. Lobana, R. Singh, Trans. Met. Chem. 20 (1995) 501.
[29] A.A. Soliman, Spectrochim. Acta A 67 (2007) 852.
The coordination capability and bonding interactions of
three functionalized tripodal phosphine chalcogen donors lig-
ands, viz. [CH3C(CH2P(Se)Ph2)3](a), [CH3C(CH2P(S)Ph2)3](b) and
[CH3C(CH2P(O)Ph2)3](c) toward [Ru(CO)2Cl2]n were studied. The
ligands a–c favour to generate hexa-coordinated ␩2-X,X bonded
complexes of the type [Ru(CO)2Cl2(CH3C(CH2P-(X)Ph2)3)] (1a–c)
leaving one arm dangling. ‘Soft–Hard’ and ‘Soft–Soft’ interactions
between the metal and the chalcogen donors for the complexes
1a–c are found to be operative. Such complexes may find appli-