Easy synthesis and water solubility of ruthenium complexes containing PPh3, mTPPMS, PTA and mPTA, (mTPPMS = meta-triphenyphosphine monosulfonate, PTA = 1,3,5-triaza-7-phosphaadamantane, mPTA = N-methyl-1,3,5-triaza-7-phosphaadamantane)

Article abstract of DOI:10.1016/j.ica.2016.06.019

New water soluble {CpRu} complexes with formula [RuCpX(L¹)(L²)]ⁿ⁺(L¹, L²= PPh₃, mTPPMS (meta-triphenyphsphine monosulfonate), PTA (1,3,5-triaza-7-phosphaadamantane), mPTA (N-methyl-1,3,5-triaza-7-phosphaadamantane)) were synthesized and characterized by elemental analytical, IR and NMR spectroscopy. Complexes [RuClCp(PPh₃)(mPTA)](OTf) (3·OTf), [RuCpI(PPh₃)(mPTA)]·2I·EtOH (5·I·EtOH)·and [RuCpBr(PTA)₂]·3.5H₂O (6·3.5H₂O) were also characterized by single crystal X-ray diffraction. The NMR spectra of the complexes are in agreement with their composition, indicating also that their solid state structure is maintained in solution. These results are integrated in a thorough overview of preparative routes, structural composition and solubility of {CpRu} complexes containing water-soluble phosphanes.

Full text of DOI:10.1016/j.ica.2016.06.019

Inorganica Chimica Acta xxx (2016) xxx–xxx
Contents lists available at ScienceDirect
Inorganica Chimica Acta
journal homepage: www.elsevier.com/locate/ica
Research paper
Easy synthesis and water solubility of ruthenium complexes containing
PPh3, mTPPMS, PTA and mPTA, (mTPPMS = meta-triphenyphosphine
monosulfonate, PTA = 1,3,5-triaza-7-phosphaadamantane,
mPTA = N-methyl-1,3,5-triaza-7-phosphaadamantane)
Manuel Serrano-Ruiz a, Pablo Lorenzo-Luis b, , Antonio Romerosa a,
⇑
⇑
a Área de Química Inorgánica-CIESOL, Facultad de Ciencias, Universidad de Almería, Almería, Spain
b Departamento de Química-Área de Inorgánica, Facultad de Química, Universidad de La Laguna, La Laguna, Tenerife, Spain
a r t i c l e i n f o
a b s t r a c t
New water soluble {CpRu} complexes with formula [RuCpX(L1)(L2)]n+ (L1, L2 = PPh3, mTPPMS (meta-triph-
enyphsphine monosulfonate), PTA (1,3,5-triaza-7-phosphaadamantane), mPTA (N-methyl-1,3,5-triaza-7-
phosphaadamantane)) were synthesized and characterized by elemental analytical, IR and NMR
spectroscopy. Complexes [RuClCp(PPh3)(mPTA)](OTf) (3ꢀOTf), [RuCpI(PPh3)(mPTA)]ꢀ2IꢀEtOH (5ꢀIꢀEtOH)ꢀ
and [RuCpBr(PTA)2]ꢀ3.5H2O (6ꢀ3.5H2O) were also characterized by single crystal X-ray diffraction. The
NMR spectra of the complexes are in agreement with their composition, indicating also that their solid
state structure is maintained in solution. These results are integrated in a thorough overview of preparative
routes, structural composition and solubility of {CpRu} complexes containing water-soluble phosphanes.
Ó 2016 Elsevier B.V. All rights reserved.
Article history:
Received 20 April 2016
Received in revised form 7 June 2016
Accepted 9 June 2016
Available online xxxx
Keywords:
Ruthenium
Water soluble complexes
Water soluble phosphanes
1. Introduction
complexes constitute an entire family of {CpRu}-complexes with
similar structure, which provide the possibility of correlating
Pearson’s hard-soft acid-base (HSAB) principle, introduced in
1963 [1] has become one of the central constructs of modern
chemistry. The HSAB principle is useful in making qualitative esti-
mates of the solubility of ionic salts in water and to some extent in
other solvents, though not many other solvents yield solvation
energies large enough to dissolve many ionic salts. As a general
strategy aqua-soluble ligands are used to provide water solubility
to metal complexes. Nevertheless, there is not an extensive study
on complex solubility in water related with complex composition,
structure and, number and nature of water-soluble ligands. Over
the last years, we have published the synthesis of the piano-stool
complexes [RuCp0X(L1)(L2)]n+ (Cp0 = Cp; Cp⁄; X = Cl, I, L1 = PPh3;
L2 = PTA, mPTA; L1 = L2 = PTA, mPTA), Na2[RuCpX(mTPPMS)2]
(X = Cl, I) and Nax[RuCp(mTPPMS)(PR13)(PR32)](OTf)y (PR31 = PR32 =
PPh3, PTA, x = y = 0. PR31 = mTPPMS, PR32 = PTA, x = 1, y = 0. PR13 =
mTPPMS, PR23 = mPTA, x = y = 0. PR31 = PR23 = mTPPMS, x = 2, y = 0.
PR31 = PPh3, PR32 = PTA, x = y = 0. PR31 = mPTA, PR32 = PPh3, x = 0, y = 1)
(mTPPMS = meta-triphenyphsphine monosulfonate; OTf = ꢁOSO2
CF3; PTA = 1,3,5-triaza-7-phosphaadamantane; mPTA = N-methyl-
PTA) and reported on their interaction with DNA [2,3,4]. These
composition with solubility in water.
This paper describes the synthesis and characterization of new
water soluble half-sandwich ruthenium(II) complexes with halides
and/or hydrophobic (PPh3), amphiphilic (mTPPMS) and hydrophi-
lic (PTA and mPTA) phosphane coligands which are needed to
arrive to have a more complete overview about the relation
between structure and water solubility of the complex family of
general formula [RuCpX(L1)(L2)]n+ (X = Cl, Br, I; L1 = PPh3; mTPPMS,
L2 = mPTA, PTA; L1 = L2 = PTA, mPTA).
2. Experimental
2.1. Materials and methods
All reagents and chemicals were reagent grade and, unless
otherwise stated, were used as received by commercial suppliers.
All reactions and manipulations were routinely performed under
a dry nitrogen atmosphere. The solid complexes were collected
on sintered glass-frits and purified as described. The aryl-sul-
fonated (mTPPMS) and the cage-like phosphines (PTA and mPTA)
as well as the complexes [RuClCp(PPh3)2], Na2[RuClCp(mTPPMS)2],
[RuClCp(PPh3)(mPTA)](OTf) (3ꢀOTf), [RuClCp(PPh3)(PTA)] and
[RuClCp(PTA)2], were prepared as described in the literature [2–5].
⇑
Corresponding authors.
E-mail addresses: plorenzo@ull.es (P. Lorenzo-Luis), romerosa@ual.es
(A. Romerosa).
http://dx.doi.org/10.1016/j.ica.2016.06.019
0020-1693/Ó 2016 Elsevier B.V. All rights reserved.
Please cite this article in press as: M. Serrano-Ruiz et al., Inorg. Chim. Acta (2016), http://dx.doi.org/10.1016/j.ica.2016.06.019

2
M. Serrano-Ruiz et al. / Inorganica Chimica Acta xxx (2016) xxx–xxx
The deuterated solvents CD3OD, DMSO-d6 and CDCl3 (Cortec-
evaporation from a solution of 3ꢀOTf in CHCl3/n-hexane (1:1) (syn-
thesis in Scheme 1 and X-ray structure in Fig. 2). Crystal data and
structure refinement information are listed in Table 1.
Euriso-top) was dried over molecular sieves (0.4 nm). 1H and 13C
{1H} NMR spectra were recorded on a Bruker DRX300 spectrome-
ters operating at 300.13 MHz (1H) and 75.47 MHz (13C), respec-
tively. Peak positions are relative to tetramethylsilane and were
calibrated against the residual solvent resonance (1H) or the
deuterated solvent multiplet (13C). 31P{1H} and 19F{1H} NMR spec-
tra were recorded on the same instruments operating at
121.49 MHz and 282.40 MHz. The chemical shifts were measured
relative to external 85% H3PO4 and CFCl3 with downfield values
taken as positive. Infrared spectra were recorded on KBr disks
using an IR-ATI Mattson Infinity Series. Elemental analysis (C, H,
N, S) were performed on a Fisons Instruments EA 1108 elemental
analyser.
2.5. Synthesis of [RuCp(PPh3)(PTA)(mPTA)](OTf)(Cl) (4ꢀOTfꢀCl)
A solution of mPTA(OSO2CF3) (0.1 g, 0.32 mmol) in 2 cm3 of
MeOH was added to [RuClCp(PPh3)(PTA)] [4] (0.2 g, 0.32 mmol)
previously dissolved in 3 cm3 of MeOH. The mixture was stirred
for 15 min at room temperature and then to refluxing temperature.
After 1 h the yellow solution was slowly cooled at room tempera-
ture and yellow-orange microcrystals were obtained, which were
filtered and dried under an argon flow. Powder yield: 0.18 g, 90%.
(mg/cm3): 0.4. Anal. Calc. (C37H47ClN6P3RuSO3F3)
(942.32): C, 47.2; H, 5.0; N, 8.9; S, 3.4. Found: C, 48.5; H, 5.1; N,
9.1; S, 3.4%. FT-IR (KBr, cmꢁ1 (SO3). 1H NMR
1196 for
2OÞ25ꢃ
SðH
C
2.2. Synthesis of Na[RuCp(mTPPMS)2(PPh3)] (1)
)
m
To an ethanolic solution of Na2[RuClCp(mTPPMS)2] [4] (0.36 g,
0.39 mmol) was added gradually NaBF4 (0.04 g, 0.37 mmol). The
reaction mixture was sonicated 30 min. giving rise to a white pre-
cipitate, which was filtered. Then PPh3 (0.097 g, 0.37 mmol) was
added to the yellow solution and the mixture refluxed for 5 min.
The resulting solution was concentrated until 0.5 cm3 and the
obtained yellow precipitate filtered, washed with EtO2
(3 ꢂ 2 cm3) and dried under vacuum. Powder yield: 0.28 g, 63%.
(mg/cm3): 8.3. Anal. Calc. (C59H48NaO6P3RuS2)
2OÞ25ꢃ
SðH
C
(1134.13): C, 62.5; H, 4.3; S, 5.6%. Found C, 60.9; H; 4.0, S, 5.3%.
FT-IR (KBr, cmꢁ1 (SO3). 1H NMR
1185 and 1222 for
(300.13 MHz, 20 °C, CD3OD): (ppm) 4.15 (bm, Cp, H),
)
m
d
5
7.13–8.17 (m, aromatic, 43 H); 13C{1H} NMR (75.47 MHz, 20 °C,
CD3OD): d (ppm) 81.18 (bm, Cp), 126.19–145.73 (m, aromatic);
31P{1H} NMR (121.49, 20 °C, CD3OD): d (ppm) 39.60 (AXY system,
1J(PPh3/mTPPMS) = 49.9 Hz, 1J(PPh3/mTPPMS) = 46.2 Hz, PPh3); 39.80
1
(bd, J(mTPPMS/PPh3) = 46.2 Hz, mTPPMS).
2.3. Synthesis of [RuCp(PPh3)2(mPTA)](OTf)(BF4) (2ꢀOTfꢀBF4)
The complex [RuClCp(PPh3)2] [2] (0.29 g, 0.40 mmol), mPTA
(OSO2CF3) (0.145 g, 0.45 mmol) and NaBF4 (0.049 g, 0.45 mmol)
were introduced into a vessel containing 50 cm3 of EtOH. The
resulting mixture was kept at refluxing temperature for 12 h and
evaporated under vacuum until 10 cm3. The obtained yellow pre-
cipitate was filtered, washed with Et2O (2 ꢂ 5 cm3) and vacuum
2OÞ25ꢃ
dried. Powder yield: 0.332 g, 75%. SðH
(mg/cm3): 2.7. Anal.
C
Calc. (C49H50N3P3RuSO3BF7) (1098.81): C, 53.1; H, 4.6; N, 3.8; S,
2.9%. Found C, 51.9; H, 4.3; N, 3.6; S, 3.6%. FT-IR (KBr, cmꢁ1
1253 and 1273 for
(OSO). 1H NMR (300.13 MHz, 20 °C, CDCl3):
)
m
2
d (ppm) 2.87 (s, CH3N, 3 H), 2.89 (ABX system, JHH = 1.8 Hz,
2JHP = 8.34 Hz, CH3NCHP, 2H), 3.51 (ABX system, JHH = 6.18 Hz,
2
2JHP = 15.07 Hz, PCH2N, 2 H), 3.81–4.39 (m, CH3NCH2N, 4 H),
4.66–5.01 (m, NCH2N, 2 H), 5.13 (s, Cp, 5 H), 7.09–7.66 (m, aro-
matic, 30 H); 13C{1H} NMR (75.47 MHz, 20 °C, D2O): d (ppm)
1
48.66 (s, CH3N), 51.85 (d, JCP = 13.81 Hz, PCH2N), 60.90 (d,
1JCP = 10.21 Hz, PCH2NCH3), 68.52 (d, JCP = 6.0 NCH2N), 79.65 (d,
3
3JCP = 3.61 Hz, NCH2NCH3), 85.93 (s, Cp), 128.95–136.54 (aromatic,
PPh3); 31P{1H} NMR (121.49, 20 °C, CDCl3): d (ppm) ꢁ25.48 (t,
2JPP = 39.6 Hz, mPTA), 39.33 (d, JPP = 40.35 Hz,, PPh3, 2 P); 19F{1H}
2
NMR (282.40, 20 °C, D2O): d (ppm) ꢁ78.98 (s, ꢁOTf), d (ppm)
ꢁ150.19 (s, BFꢁ4 ).
2.4. Synthesis of [RuCpCl(PPh3)(mPTA)](OTf) (3ꢀOTf)
Complex 3ꢀOTf was prepared by following the method reported
by us [3]. The conditions to obtain this complex were optimized
and crystals suitable for X-ray diffraction were grown by slow
Scheme 1. Synthetic pathway for the family of organoruthenium complexes
(mTPPMS = meta-triphenyphsphine monosulfonate; PTA = 1,3,5-triaza-7-phos-
phaadamantane; mPTA = N-methyl-PTA); OTf = ꢁOSO2CF3.
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M. Serrano-Ruiz et al. / Inorganica Chimica Acta xxx (2016) xxx–xxx
3
2.6. Synthesis of [RuCpI(PPh3)(mPTA)]ꢀIꢀEtOH (5ꢀIꢀEtOH)ꢀ
Complex 5ꢀIꢀEtOH was prepared by reaction of 3ꢀOTf with NaI in
refluxing EtOH by slight modification of the method previously
2OÞ25ꢃ
published by us [3]. Powder yield: 0.105 g (45%). SðH
(mg/
C
cm3): 60.1 mg/cm3. Anal. Calc. (C32H41I2N3P2RuO) (900.53): C,
42.7; H, 4.6; N, 4.7. Found C, 42.5; H; 4.0, N, 4.1%. Crystals were
undertaken by slow evaporation from EtOH/NaI (1:1.5).
2.7. Synthesis of [RuCpBr(PTA)2]ꢀ3ꢀ5H2O (6ꢀ3ꢀ5H2O)
Fig. 1. Combination of phosphines to provide control over the water-solubility of
the family of complexes with formula [RuCpX(L1)(L2)]n+ (X = Cl, Br, I; L1 = PPh3;
mTPPMS, L2 = mPTA, PTA; L1 = L2 = PTA, mPTA).
A solution of [RuCpCl(PTA)2] [2,5] (0.10 g, 0,14 mmol) in 20 cm3
of MeOH was reacted with KBr (0.025 g, 0,21 mmol). The mixture
refluxed for 4 h, cooled down to room temperature and concen-
trated under reduced pressure to dryness. Addition of 10 cm3 of
hot CH3Cl with strong stirring afforded a yellow precipitate that
was filtered, washed with Et2O (3 ꢂ 3 cm3) and vacuum dried. Slow
evaporation in water solution enabled obtaining crystals of good
quality (X-ray structure in Fig. 4). Crystal data and structure refine-
ment information are listed in Table 1. Power yield: 0.035 g, 81%.
(mg/cm3): 30. Anal. Calc. (C17H36BrN6P2RuO3.5) (623.44):
2OÞ25ꢃ
SðH
C
C, 32.7; H, 5.8; N, 13.5. Found: C, 31.9; H, 5.4; N, 13.1%. 1H NMR
(300,13 MHz, D2O, 20 °C): d (ppm) 3.97 (ABX system, 2JHH = 15.0 Hz,
2JHP = 15.0 Hz, NCH2P, 6H), 4.46 (bs, NCH2N, 6H), 4.66 (s, Cp,
5H); 13C{1H} NMR (75.47 MHz, D2O, 20 °C):
d (ppm) 54.80
1
3
(t, JCP = 9.0 Hz, NCH2P), 70.56 (t, JCP = 3.0 Hz, NCH2N), 77.01
3
(t, JCP = 1.8 Hz, Cp). 31P{1H} NMR (121.49 Mz, D2O, 20 °C):
Fig. 2. A perspective drawing of 3ꢀOTf with atom numbering. Dashed lines
d (ppm) ꢁ26.37 (s, PTA).
represent the select inter-molecular interactions.
2.8. Synthesis of [RuCp(PTA)2(mPTA)](OTf)ꢀ(Cl) (7ꢀOTfꢀCl)
(300.13 MHz, 20 °C, CD3OD): d (ppm) 2.82 (bs, CH3NmPTA, 3 H),
3.62–4.00 (m, CH2PPTA + CH2PmPTA, 10 H), 4.16–4.59 (m, CH2NPTA
+
Into
a vessel the complex [RuClCp(PTA)2] [2,5] (0.1 g,
0.19 mmol), mPTA(OSO2CF3) (0.06 g, 0.19 mmol) and 15 cm3 of
MeOH were introduced. The mixture was kept at refluxing temper-
ature for 1 day. The resulting pale-yellow precipitate was filtered,
washed with MeOH (2 ꢂ 3 cm3), Et2O (2 ꢂ 2 cm3) and vacuum
CH2NmPTA, 8 H), 3.77–5.13 (m, CH2NmPTA + CH2PmPTA, 6 H), 5.25
(s, Cp, 5 H), 7.31–7.64 (m, aromatic protons, 15 H); 13C{1H} NMR
(75.47 MHz, 20 °C, CD3OD): d (ppm) 53.07 (s, CH3(mPTA)-N), 56.60
1
(m, CPPTA), 56.80 (m, CPmPTA), 61.50 (d, JCP = 3.6 Hz, CH3NCPmPTA),
dried. Powder yield: 0.09 g, 57%. SðH
(mg/cm3): 200. Anal.
C
71.41, 71.46 (m, NCNPTA + NCNmPTA), 79.86 (m, CH3NCNmPTA), 84.20
2OÞ25ꢃ
(bs, Cp), 129.03–136.16 (m, PPh3); 31P{1H} NMR (121.49, 20 °C,
Calc. (C25H44ClN9P3RuSO3F3) (837.18): C, 35.9; H, 5.3; N, 15.1; S,
3.8%. Found: C, 36.2; H, 5.5; N, 15.0; S, 4.0%. FT-IR (KBr, cmꢁ1
1244, 1258 and 1280 for
(SO3). 1H NMR (300.13 MHz, 20 °C,
D2O): d (ppm) 2.82 (bd, JHP = 1.8 Hz, CH3NmPTAN, 3 H), 3.94 (ABX
1
DMSO):
d
(ppm) ꢁ39.40 (AMX system, J(PTA/mPTA) = 35.4 Hz,
)
1J(PTA/PPh3) = 36.0 Hz, PTA), ꢁ16.18 (AMX system, J(mPTA/mPTA)
=
1
m
1
4
35.4 Hz, J(mPTA/PPh3) = 35.3 Hz, mPTA), 47.22 (AMX system,
1J(PPh3/PTA) = 35.3 Hz, J(PPh3/mPTA) = 36.0 Hz, PPh3), 19F{1H} NMR
1
2
2
system, JHH = 13.7 Hz, JHP = 45.9 Hz, PCH2NmPTA, 4 H), 4.27 (bs,
(282.40, 20 °C, MeOH): d (ppm) ꢁ78.98 (s, OTf).
CH3NCH2PmPTA, 2 H), 4.34–4.50 (m, NCH2NPTA, 6 H), 4.54–4.63
Table 1
Crystal data and structure refinement information for complexes 3ꢀOTf, 5ꢀIꢀEtOH and 6ꢀ3.5H2O.
3ꢀOTf
5ꢀIꢀEtOH
6ꢀ3.5H2O
Empirical formula
Formula weight
Crystal system
Space group
a (Å)
C
31H35ClN3P2RuO3SF3
C32H35I2N3P2RuO
894.44
C17H36BrN6P2RuO3.5
623.44
785.14
triclinic
triclinic
monoclinic
ꢀ
ꢀ
ꢀ
P
P
P21/c 1
9.073(4)
9.4749(4)
11.8703(6)
b (Å)
c (Å)
13.535(5)
14.167(6)
76.099(6)
79.343(9)
78.203(7)
1636.2(11)
2
1.594
0.71073
0.777
800
13.6140(6)
14.0751(6)
89.8630(10)
72.3720(10)
76.6490(10)
1679.08(13)
2
1.769
0.71069
2.430
872
14.6036(7)
14.1137(7)
90
107.6830(10)
90
2331.0(2)
4
1.756
0.71069
2.558
1240
a
(°)
b (°)
c
(°)
V (Å3)
Z
Calculated density (gꢀcmꢁ3
k (Å)
)
Absorption coefficient (mmꢁ1
F(0 0 0)
)
Data/restraints/parameters
Final R indices [I > 2r(I)]
4644/0/404
R1 = 0.0745; wR2 = 0.1497
R1 = 0.1236; wR2 = 0.1725
0.998
5846/0/369
R1 = 0.0308; wR2 = 0.0792
R1 = 0.0342; wR2 = 0.0811
1.058
4098 /0/280
R1 = 0.0493; wR2 = 0.0910
R1 = 0.0662; wR2 = 0.0965
1.067
wR2 R indices (all data)
Goodness of fit (GOF) on F2
Largest difference in peak and hole (eꢀÅꢁ3
)
1.079 and ꢁ0.893
1.132 and ꢁ0.562
1.04 and ꢁ0.785
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4
M. Serrano-Ruiz et al. / Inorganica Chimica Acta xxx (2016) xxx–xxx
full-matrix least-squares techniques on F2 with SHELXL [6]. The
C-bonded hydrogen atoms were included in idealized geometry
riding on their parent atoms with C–H = 0.93–0.99 Å. The triflate
anion (OTf = ꢁOSO2CF3) for 3ꢀOTf, was found to be disordered and
refined isotropically, with Uiso(F1T/F2T) = 0.33 and 0.63; Uiso
(F3T/F4T) = 0.72 and 0.28 and Uiso(F5T/F6T) = 0.79 and 0.21.
The ethanol molecule in 5ꢀIꢀEtOH is disordered between two
positions with occupancy factors of Uiso(C1E/C2E) = 0.81 and
0.21 and Uiso(C3E/C4E) = 0.61 and 0.41. The water molecules for
6ꢀ3ꢀ5H2O were refined anisotropically, with Uani (Ow4) = 0.5. A
brief summary of crystallographic details is given in Table 1.
Fig. 3. A perspective drawing of 5ꢀIꢀEtOH with atom numbering. For the sake of
clarity, the dashed line C4P-H4PAꢀ ꢀ ꢀO1E was omitted.
3. Results and discussion
3.1. Synthesis and characterization
One of the most popular synthetic routes to obtain aqueous
organometallic complexes is the incorporation of water-soluble
phosphines within the metal coordination sphere. A wide variety
of functionalized aqua-soluble phosphines are actually known
and their effectiveness in the aqueous organometallic chemistry
context used [2–5].
We have synthesized a series of {CpRu} complexes of general
formula [RuCpX(L1)(L2)]n+ (X = Cl, Br, I; L1 = PPh3; mTPPMS,
L2 = mPTA, PTA; L1 = L2 = PTA, mPTA) (Table 2) that constitute an
entire family with the same piano-stool structure in which three
coordination positions on the Ru are occupied by one Cp and
remaining coordination positions available for ancillary ligands.
The steric and electronic properties of the benchmark ligand
PPh3 have a large effect on their poor solubility in water as far
the bulky aryl ring of PPh3 (cone angle h = 145°) causes a severe
reduction on the water-solubility of the complexes (vide infra)
[3]. In contrast, its meta-sulfonated derivative, the mTPPMS, dis-
play a large cone angle (h = 151°) [7] but also a larger solubility
Fig. 4. A perspective drawing of 6ꢀ3ꢀ5H2O with atom numbering. Dashed lines
represent the select inter-molecular interactions. For the sake of clarity, the dashed
lines for Ow1; Ow2 and Ow3 were omitted.
(2d, 1JHH = 13.7 Hz, NCH2NmPTA, 2 H), 4.88–5.10 (m, CH3NCH2NmPTA
,
4 H); 5.26 (s, Cp, 5 H); 13C{1H} NMR (75.47 MHz, 20 °C, D2O): d
1
(ppm) 48.82 (s, CH3NmPTA), 54.49 (d, JCP = 17.3 Hz, PCH2NmPTA),
56.87 (d, 1JCP = 9.7 Hz, PCH2NPTA), 62.07–62.27 (m, CH3PCH2NmPTA),
68.58–68.66 (m, NCH2NmPTA), 70.40 (s, NCH2NPTA), 79.87
(s, CH3NCH2NmPTA), 82.93 (s, Cp); 31P{1H} NMR (121.49, 20 °C,
2
= 80 mg/cm3) and behaves like an amphiphile
D2O):
d
(ppm) ꢁ25.97 (d, JPTA/mPTA = 35.4 Hz, PTA), ꢁ8.6
2OÞ20ꢃ
in water (SðH
C
(t, JmPTA/PTA) = 35.4 Hz, mPTA). 19F{1H} NMR (282.40, 20 °C, D2O):
2
[8], providing a significant water solubility to its metal complexes.
d (ppm) ꢁ78.98 (s, OTf).
The small (cone angle h ꢄ 103°) cage-like phosphine PTA (Fig. 1)
is largely soluble in water (SðH
= 235 mg/cm3) but also in
C
2OÞ25ꢃ
2.9. Synthesis of [RuCp(PTA)3](BF4) (8ꢀBF4)
most of the organic solvents such as CHCl3. The PTA derivatives
and its metal complexes use to be also water soluble. The mPTA,
the PTA mono-methylated derivative, is also largely soluble in
The ligand PTA (0.03 g, 0.191 mmol) and NaBF4 (0.11 g,
0.193 mmol) were added to a suspension of [RuClCp(PTA)2] [2,5]
(0.10 g, 0.193 mmol) in 15 cm3 of MeOH. The mixture was stirred
at room temperature for 10 min and kept to refluxing temperature
for 10 h. The resulting pale yellow precipitate was filtered, washed
with MeOH (2 ꢂ 5 cm3) and Et2O (2 ꢂ 5 cm3), vacuum dried and
then dissolved in 30 cm3 of CHCl3. The obtained suspension was fil-
tered out and evaporated under vacuum until 1 cm3. Addition of
5 cm3 of Et2OH afforded a pale yellow precipitate that was filtered
out, washed with Et2O (2 ꢂ 2 cm3) and vacuum dried. Powder
Table 2
Solubility (mg/cm3) in water at 25 °C.
ðH2 OÞ25ꢃ
C
Complex
S
Ref.
Na2[RuCpCl(mTPPMS)2]
Na2[RuCp(mTPPMS)3]
[RuCp(mTPPMS)(PPh3)2]
41.0
20.0
0.9
8.3
2.7
1.1
0.4
60.1
0.4
60.1
16
[4]
[4]
[4]
Na[RuCp(mTPPMS)2(PPh3)] (1)
[RuCp(PPh3)2(mPTA)](OTf)(BF4) (2ꢀOTfꢀBF4)
[RuCpCl(PPh3)(mPTA)]ꢀ(OTf) (3ꢀOTf)
[RuCp(PPh3)(PTA)(mPTA)](OTf)(Cl) (4ꢀOTfꢀCl)
[RuCpI(PPh3)(mPTA)]ꢀIꢀEtOH (5ꢀIꢀEtOH)
[RuCpI(PPh3)(mPTA)]ꢀCl
yield: 0.070 g, 51%. SðH
(mg/cm3): 40. Anal. Calc. (C23H41N9P3-
C
2OÞ25ꢃ
[3]
RuBF4) (724.44): C, 38.1; H, 5.7; N, 17.4. Found: C, 37.8; H, 5.5; N,
16.9%. 1H NMR (300.13 MHz, 20 °C, D2O): d (ppm) 3.97 (bs, NCH2-
P
PTA, 18 H), 4.48–4.60 (m, NCH2NPTA, 18 H), 4.70 (s, Cp, 5 H); 13C
[3]
[3]
{1H} NMR (75.47 MHz, 20 °C, D2O): d (ppm) 56.92 (AXY system,
[RuCpI(PPh3)(mPTA)]ꢀ(OSO2CF3)ꢀ2H2O
[RuCpCl(mPTA)2]ꢀ(OSO2CF3)2
[RuCpCl(mPTA)2]ꢀ(BF4)2
[10]
[10]
[3]
[2,5]
[2]
1JCP = 8.6 Hz, JCH = 8.6 Hz, NCH2PPTA), 70.43 (s, NCH2NPTA), 82.36
1
0.29*
32
(s, Cp); 31P{1H} NMR (121.49, 20 °C, D2O): d (ppm) ꢁ24.09 (s,
PTA). 19F{1H} NMR (282.40, 20 °C, D2O): d (ppm) ꢁ150.19 (s, BF4).
[RuCpI(mPTA)2]ꢀ(OSO2CF3)2
[RuClCp(PTA)2]
40
25
[RuCp⁄Cl(PTA)2]
[RuCpBr(PTA)2] (6ꢀ3ꢀ5H2O)
30
10
2.10. X-ray structure determinations
[RuCpI(PTA)2]
[3]
[RuClCp(HPTA)2]Cl2ꢀ2H2O
[RuCp(PTA)2(mPTA)](OTf)(Cl) (7ꢀOTfꢀCl)
[RuCp(PTA)3](BF4) (8ꢀBF4)
OTf = ꢁOSO2CF3
320
200
40
[11]
X-ray diffraction data for 3ꢀOTf, 5ꢀIꢀEtOH and 6ꢀ3ꢀ5H2O were
collected by u-x-scans technique on a Bruker APEX diffractometer
using a graphite-monochromated MoK radiation. The structures
a
*
Solubility in water at 22 °C.
were solved by direct methods with SHELXS [6] and refined with
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M. Serrano-Ruiz et al. / Inorganica Chimica Acta xxx (2016) xxx–xxx
5
2OÞ25ꢃ
water (SðH
angle than the PTA.
= 240 mg/cm3) [3,9], displaying a similar cone
C
In order to tackle this question the complex, [RuCpI(PPh3)
(mPTA)]ꢀIꢀEtOH (5ꢀIꢀEtOH) was synthesized from 3ꢀOTf (Scheme 1)
where both triflate ion and chloride ligand were replaced by iodide.
The composition of 5ꢀIꢀEtOH was clearly supported by the determi-
nation of its crystal structure by single crystal X-ray diffraction
(Table 1 and Fig. 3). It is important to stress that 5ꢀIꢀEtOH is less
Most of the complexes in this paper (2ꢀOTfꢀBF4, 4ꢀOTfꢀCl, as well
as 6ꢀ3ꢀ5H2O, 7ꢀOTfꢀCl and 8ꢀBF4) were obtained by substitution of
the Cl and PPh3 ligands in the complexes [RuCl(PPh3)2], [RuCl
(PPh3)(PTA)] and [RuCl(PTA)2] [2,3,5]. Complexes 1 and 5ꢀIꢀEtOH
were obtained respectively from the complexes Na2[RuClCp
(mTPPMS)2] [4] and [RuCpCl(PPh3)(mPTA)](OTf) (3ꢀOTf) [3], as
the direct synthesis from the starting compound was not possible
(Scheme 1).
Our research team prepared over the past few years some
piano-stool water-soluble ruthenium complexes containing
mTPPMS [4]. These complexes showed good solubility in water,
which was related to the phosphanes coordinated to the metal.
The complex [RuCp(mTPPMS)(PPh3)2] was found to be practi-
2OÞ25ꢃ
C
soluble in water than 3ꢀOTf (SðH
6 0.1 mg/cm3). This beha-
viour, has been previously observed by us for the complexes
X = Cl: 0.4 mg/cm3; X = I:
2OÞ25ꢃ
[RuCpI(PPh3)(mPTA)]ꢀ(X) (SðH
:
C
60.1 mg/cm3) [3], where the decreasing solubility can be rational-
ized in terms of anion salt effect. Therefore, reaction of NaI with
3ꢀOTf (Scheme 1) should provide a less water soluble complex,
suggesting that Iꢁ anion exhibits a comparable effect on the solu-
bility to than Clꢁ and ꢁOTf anions (Table 2).
On the other hand, this low solubility could indicate that the
strategy to modify the hydrosolubility using PPh3 in combination
with one hydrophilic coligand in the {RuCpX(L1)(L2)} moiety
(X = Cl, I; L1 = PPh3; L2 = mPTA) is invalid, but also it is possible that
more than one water soluble ligand coordinated to the metal are
required (vide infra).
2OÞ25ꢃ
C
cally insoluble in water (SðH
RuCp(mTPPMS)3] (SðH
= 0.9 mg/cm3) while the Na [-
2
= 20.0 mg/cm3) showed a significant
2OÞ25ꢃ
C
solubility but lower than that for Na2[RuCpCl(mTPPMS)2]
= 41 mg/cm3). The scarce water solubility of [RuCp
2OÞ25ꢃ
(SðH
C
(mTPPMS)(PPh3)2] denotes the strong negative effect on the water
solubility of the PPh3 ligand (Table 2).
In fact, we have found that more than one mPTA and/or PTA per
ruthenium atom is enough to achieve a significant water-solubility
(Table 2). For example, complex [RuCpCl(mPTA)2]ꢀ(OSO2CF3)2
With this precedent, we decided to investigate the reaction of
sulfonated phosphane precursor Na2[RuCpCl(mTPPMS)2] [4], with
NaBF4 and PPh3 in ethanol (Scheme 1) to obtain the new complex
Na[RuCp(mTPPMS)2(PPh3)] (1), which was isolated in moderate
good yield (75%) and characterized by means of standard spectro-
scopic techniques as well as elemental analysis. The chemical shift
in its 31P{1H} NMR spectrum of the mTPPMS ligands (39.80 ppm)
moves ca. 0.3 ppm to up-field from that observed for starting com-
plex Na2[RuCpCl(mTPPMS)2] while the chemical shift of Cp in its
1H NMR is closer (4.15 ppm) to that in starting complex
(4.21 ppm) [4].
As expected the water solubility of 1 is larger than that for
[RuCp(mTPPMS)(PPh3)2] with only one mTPPMS and two PPh3,
but lower than that for Na2[RuCp(mTPPMS)3] containing three
mTPPMS ligands (Table 2). Therefore, we might infer that the steric
and electronic properties cannot be regarded as separated factors
without influence on the complex water-solubility (vide infra) [7].
Upon reaction of [RuClCp(PPh3)2] [2] with mPTA(OTf) and
NaBF4 the new complex [RuCp(PPh3)2(mPTA)](OTf)(BF4)
(2ꢀOTfꢀBF4) was obtained by exchanging the Cl coordinated to the
metal by a mPTA ligand (Scheme 1). Its proposed structure was
supported by the appearance in the 31P{1H} NMR of a doublet at
39.33 ppm for the PPh3 and a triplet at ꢁ25.48 ppm for the mPTA.
Additionally, its 1H NMR spectrum shows signals at 2.87 ppm that
only can be due to the group CH3NmPTA [3]. It is important to point
out that the 19F{1H} NMR spectrum shows for the CF3 singlets at
ꢁ78.98 ppm and for the BF4 at ꢁ150.19 ppm, indicating that there
are no significant interaction among the metal and these anions
[10].
(SðH
= 16 mg/cm3) is more soluble in water than [RuCpCl
C
2OÞ25ꢃ
= 0.29 mg/cm3) [10] but surprisingly
2OÞ22ꢃ
C
(mPTA)2]ꢀ(BF4)2 (SðH
smaller than [RuCpI(mPTA)2]ꢀ(OSO2CF3)2 (SðH
= 32 mg/cm3)
C
2OÞ25ꢃ
[3]. The access of water molecules into the solid to interact with
complex units leading to their dissolution is known to be more
problematic for BFꢁ4 salts than for ꢁOSO2CF3 salts. Nevertheless,
this effect should not be the main reason for understand the
observed solubility trend.
To understand this behaviour, the synthesis of [RuCpBr(PTA)2]
(6ꢀ3ꢀ5H2O) was carried out (Scheme 1). This complex was obtained
by reaction of [RuClCp(PTA)2] [2,5] and KBr in refluxing methanol.
Single crystals were grown by slow evaporation from its aqueous
solution. The structure of 6ꢀ3ꢀ5H2O has been unequivocally con-
firmed by single-crystal X ray diffraction that confirms the coordi-
nation of a Br to the Ru instead of the Cl (Table 1 and Fig. 4). Its 31
P
{1H} NMR is in agreement with the observed fact that substitution
of the chloride bonded to the metal by iodide causes the chemical
shift of the phosphine resonances to move to higher field [3] (vide
infra). The chemical shift of PTA in [RuClCp(PTA)2] (-23.6 ppm) [2]
is shifted by ca. 2.8 ppm up-field than that in 6ꢀ3ꢀ5H2O and shifted
by ca. 5 ppm up-field from that [RuICp(PTA)2] [3].
2OÞ25ꢃ
C
Compound 6ꢀ3ꢀ5H2O is less water-soluble (SðH
= 30 mg/
cm3) than [RuClCp(PTA)2] [2] (SðH
= 40 mg/cm3), slightly more
= 25 mg/cm3) [2] but much
C
2OÞ25ꢃ
C
soluble than [RuCp⁄Cl(PTA)2] (SðH
2OÞ25ꢃ
more soluble than [RuCpI(PTA)2] (SðH
= 10 mg/cm3) [3].
2OÞ25ꢃ
C
Therefore, as we anticipated, when bromide or iodide replaces
chloride the solubility in water drops down.
The complex 2ꢀOTfꢀBF4 is sparsely soluble in water
From above results (Table 2) it should be noted that there are a
larger variety of factors than the number of water-soluble phosphi-
nes bonded to the metal, which can determine the solubility of
their metal-complexes. For example, we showed that reaction of
complex [RuClCp(PTA)2] [2,5] in acidic media provides the larger
water-soluble complex [RuClCp(HPTA)2]Cl2ꢀ2H2O (HPTA = 1-H-
= 2.7 mg/cm3) but larger than that for the earliest
C
2OÞ25ꢃ
(SðH
2OÞ25ꢃ
reported [RuCpCl(PPh3)(mPTA)]ꢀ(OTf) (3ꢀOTf) (SðH
= 1.1 mg/
C
cm3) [3] in spite of this complex includes only one PPh3. This fact
apparently contradicts our early supposition on the influence of
the number of PPh3 ligands coordinate to the metal.
1,3,5-triaza-7-phosphaadamantane) (SðH
= 320 mg/cm3) [11].
C
To further verify the effect of the PPh3 on the water solubility of
this complex family, the new member [RuCp(PPh3)(PTA)(mPTA)]
(OTf)(Cl) (4ꢀOTfꢀCl) was synthesized (Scheme 1). The 31P{1H}
NMR spectrum displays an AMX system at ꢁ39.40 ppm for the
PTA, at ꢁ16.18 ppm due to mPTA and at 47.22 ppm for the PPh3.
Compound 4ꢀOTfꢀCl however displays a lower water solubility
2OÞ25ꢃ
In order to complete our study, the complexes
[RuCp(PTA)2(mPTA)](OTf)(Cl) (7ꢀOTfꢀCl) and [RuCp(PTA)3](BF4)
(8ꢀBF4) were obtained by replacing the Cl ligand in [RuClCp
(PTA)2] [2,5] with the water-soluble phosphines mPTA and PTA
respectively, in presence of NaBF4 (Scheme 1). This metathesis
reaction was confirmed by the appearance in the 31P{1H} NMR
of a triplet at ꢁ8.6 ppm (mPTA) in 7ꢀOTfꢀCl and a singlet at
–24.09 ppm (PTA) in 8ꢀBF4. As expected (vide supra), the chemical
(SðH
= 0.4 mg/cm3) than that of 3ꢀOTf (Table 2). This fact sug-
2OÞ25ꢃ
C
gested that the water solubility of these complexes could be also
affected by counterion salt effects and/or halide coligands.
Please cite this article in press as: M. Serrano-Ruiz et al., Inorg. Chim. Acta (2016), http://dx.doi.org/10.1016/j.ica.2016.06.019

6
M. Serrano-Ruiz et al. / Inorganica Chimica Acta xxx (2016) xxx–xxx
shift of PTA in [RuClCp(PTA)2] (ꢁ23.6 ppm) [2] is shifted by ca.
2.4 ppm up-field than that in 7ꢀOTfꢀCl, which is closer to that in
6ꢀ3ꢀ5H2O, and shifted by ca. 0.5 ppm up-field from that 8ꢀBF4. In
the 1H NMR spectrum of 7ꢀOTfꢀCl the Cp chemical shift arises
shifted by ca. 0.6 ppm down-field from that observed for 8ꢀBF4,
while is almost the same than that found for 2ꢀOTfꢀBF4. Finally,
the 19F{1H} NMR spectrum shows that for both complexes there
are no significant interaction between the metal and anions [10].
Surprisingly, 8ꢀBF4, which contains three PTA, displays the same
Selected distances and angles for 5ꢀIꢀEtOH are displayed in
Table 3. The asymmetric unit of this complex is constituted by a
chiral molecule containing a metal coordinated to a Cp, a PPh3,
an iodide and a mPTA coordinated by the P (Fig. 3).
We must note that, compound 5ꢀIꢀEtOH is constituted by the
same complex but different counter ions than [RuCpI(PPh3)
(mPTA)]ꢀ(OSO2CF3)ꢀ2H2O, which was previously described by us
[3]. This last compound crystallises in the monoclinic system
(P21/c space group), while compound 5ꢀIꢀEtOH crystallises in the
ꢀ
2OÞ25ꢃ
water-solubility (SðH
= 40 mg/cm3) than [RuClCp(PTA)2] [2,5]
C
triclinic system (P space group).
with only two PTA, but significantly lower than 7ꢀOTfꢀCl
The geometry of the complex is quite similar to that of 3ꢀOTf
discussed previously. The Cp ring is practically planar with the lar-
ger separation from the overal Cp plane of only 0.0085 Å (C5). The
Ru-Cpcentroid distance (1.851 Å) is consistent with the values
reported for [RuCpI(PPh3)(PTA)] (1.852 Å) and [RuCpI(PPh3)
(mPTA)]+ (1.8563(7) Å) [3].
= 200 mg/cm3) that contains one mPTA and two PTA.
2OÞ25ꢃ
(SðH
C
However, this last complex displays much more water-solubility
than 4ꢀOTfꢀCl (Table 2), which is constituted by one PTA, one mPTA
and one PPh3.
3.2. Crystal structures
The coordination P1-Ru1-P2 angle, is found to be 99.42(4)°,
which is slightly shorter than in [RuCpI(PPh3)(mPTA)]+ (100.12
(8)°) and ca. 2.1° greater than that found for [RuCpI(PPh3)(PTA)]+
(97.31(4)°) [3]. This fact suggests that the steric interactions are
similar in both complexes.
The asymmetric unit of 3ꢀOTf is constituted by one triflate anion
disordered by rotation around the C-S bond and the enantiomeric
cationic unit [RuCpCl(PPh3)(mPTA)]+.
Selected distances and angles are collected in Table 3. The
ruthenium atom is coordinated with a pseudo-octahedral geome-
The Ru-I distance in 5ꢀIꢀEtOH (2.7164(4) Å shortened respecting
to [RuCpI(PPh3)(PTA)]+ (2.7514(4) Å) but, match closely to that
found in [RuCpI(PPh3)(mPTA)]+ (2.724 Å) as well as to the mean
value (2.711 Å) for the known [CpRuIL2] complex structures [3].
The crystal structure of 6ꢀ3ꢀ5H2O is constituted by a achiral unit
try to one g
5-Cp, formally occupying three contiguous coordination
positions, one Cl, one PPh3 and one mPTA. Actuation of the symme-
try element (ꢁ1) leads to the enantiomeric unit (Fig. 2) and, there-
fore, 3ꢀOTf is
a
racemate constituted by the two possible
[RuCpBr(PTA)2] made by a ruthenium coordinated to a g
5-Cp, a Br
enantiomers obtained by distribution of the four different ligands
around the Ru atom.
and two PTA bonded by the P atom. A perspective drawing is
shown in Fig. 4 and selected distances and angles in Table 3.
The coordination polyhedron about the metal atom adopts a
highly distorted pseudo-octahedral geometry (P1-Ru1-P2 = 98.13
(6)°). This angle value is larger than that found for [RuClCp0(L2)]
(Cp0 = Cp, Cp⁄; L2 = PTA; HPTA) (93.30(5)–96.85(5)°, mean 95.44
(6)°) [2,5,11] and shorter than [RuClCp(mPTA)2]2+ (99.44(4)°)
[10]. This result is intriguing due to the larger size of bromide that,
likely increases the repulsion between the halide ligand and the
other coordinated ligands.
The P1-Ru1-P2 angle is found to be 99.02(10)°, in line to that
found in [RuCpCl(PPh3)(PTA)] (mean 98.99(8)°) [3] and slightly
higher than in [RuClCp(PPh3)(dmoPTA)]+ (98.37(9)°) [12]. The Cp
ring is essentially planar, the biggest separation being 0.017 Å (C1).
The Ru-Cpcentroid distance is 1.839 Å, comparable with that for
those complexes earliest report containing PTA (mean 1.847 Å)
[3] and dmoPTA (1.860 Å) [12]. The Ru-PmPTA separation (Ru1-
P2 = 2.261(3) Å) match closely to that found in [RuClCp(mPTA)2]2+
(mean 2.255(12) Å) [10] but is shorter than in [RuClCp(PPh3)
(dmoPTA)]+ (2.277(3) Å) [12].
These observations are consistent with the greater steric and
electrodonating properties of PPh3 versus PTA-derivatives and
Cp⁄ versus Cp, which should have anticipated dissimilar
intramolecular repulsions in related piano-stool complexes [3,5].
Another important metrical characteristic are as follows: The Cp
ring is practically planar with the larger separation from the overall
Cp plane of only 0.0035 Å (C34). The Ru-Cpcentroid distance
(1.849 Å) comparable with the values found in bibliography (range
1.840-1.861 Å, median: 1.849 Å) [3,10,11]. The Ru-Br distance
(2.5832(7) Å), identical to those found for the Ru(II)-aminophos-
The Ru-Cl distance (2.447(3) Å) in line with the average value
(medium: Ru-Cl = 2.447(7) Å) found in bibliography [2,3,5,10–12].
Table 3
Selected distances (Å) and angles (°) for 3ꢀOTf, 5ꢀIꢀEtOH and 6ꢀ3.5H2O.
3ꢀOTf
Ru-P1
2.300(3)
2.261(3)
2.447(3)
1.839
99.02(10)
90.96(9)
87.60(9)
Ru-P2
Ru-Cl1
Ru-Cpcentroid
P2-Ru-P1
P1-Ru-Cl1
P2-Ru-Cl1
phine complexes [RuCp-(PN-jN,j
P)(CH3CN)]+ (2.589(2) Å) [13].
Figs. 2 and 3 show a perspective view of the crystal packing for
3ꢀOTf and 5ꢀIꢀEtOH, respectively. The disordered triflate anion and
ethanol molecules, respectively, have been interspersed in the lat-
tice, clearly located between the C23-H23ꢀ ꢀ ꢀF5T (2.554(3) Å) for
3ꢀOTf and C7P-H7PBꢀ ꢀ ꢀO1E (2.560(5) Å) and C4P-H4PAꢀ ꢀ ꢀO1E
(2.417(5) Å) for 5ꢀIꢀEtOH.
5ꢀIꢀEtOH
Ru-P1
Ru-P2
2.3077(10)
2.2609(10)
2.7164(4)
1.851
99.42(4)
90.75(3)
87.72(3)
Ru-I1
It is also worth mentioned that in this complex the iodide coun-
terions are all anchored through hydrogen-bonding interactions
C1P-H1PBꢀ ꢀ ꢀI2 (3.052(2) Å) and C7P-H7PCꢀ ꢀ ꢀI2 (3.061(3) Å).
The structure of the compound 6ꢀ3ꢀ5H2O (Fig. 4) can be visu-
Ru-Cpcentroid
P2-Ru-P1
P1-Ru-I1
P2-Ru-I1
6ꢀ3.5H2O
Ru1-P1
Ru1-P2
alised as two achiral units [RuCpBr(PTA)2] linked in the
l2-Ow4.
2.2587(16)
2.2644(17)
2.5832(7)
1.849
98.13(6)
91.01(4)
89.21(4)
The Ow4-N11 distances through this bridging are: 2.790(2) Å for
N11 (1 ꢁ x, 0.5 + y, 0.5 ꢁ z) and 2.890(1) Å for N11 (x, 0.5 ꢁ y,
ꢁ0.5 + z).
Ru1-Br1
Ru-Cpcentroid
P1-Ru1-P2
P1-Ru1-Br1
P2-Ru1-Br1
Likewise, in the crystal packing diagrams from the three com-
plexes another weak intermolecular interaction provides addi-
tional stabilization of their crystal structure (Table 4).
Please cite this article in press as: M. Serrano-Ruiz et al., Inorg. Chim. Acta (2016), http://dx.doi.org/10.1016/j.ica.2016.06.019

M. Serrano-Ruiz et al. / Inorganica Chimica Acta xxx (2016) xxx–xxx
7
Table 4
PTA in the {RuCpX} moiety (X = Cl, Br, I) becomes more soluble
as the ionic radii of halide ligand decreases.
Additional weak intermolecular interactions for 3ꢀOTf, 5ꢀIꢀEtOH and 6ꢀ3ꢀ5H2O. D and
A stand for donor and acceptor, respectively.
D–Hꢀ ꢀ ꢀA
DꢀꢀꢀA (Å)
Hꢀ ꢀ ꢀA (Å)
Acknowledgments
3ꢀOTf
C3P-H3P1ꢀ ꢀ ꢀCl1
C6P-H6P2ꢀ ꢀ ꢀCl1
C36-H36ꢀ ꢀ ꢀCl1
3.738(1)
3.687(2)
3.633(1)
2.850(3)
2.762(3)
2.843(3)
Thanks are given to the European Commission FEDER program
for cofinancing the projects CTQ2015-67384-R (MINECO) and P09-
FQM-5402 (Junta de Andalucía). Thanks are also given to Junta de
Andalucía PAI-research group FQM-317 and COST Action CM1302
(WG1, WG2). M. S.-R. is grateful to Excellence project P09-FQM-
5402 for a postdoctoral contract. Thanks are also given to Chaker
Lidrissi and Sonia Mañas for help.
5ꢀIꢀEtOH
C1P-H1PAꢀ ꢀ ꢀI1
C2-H2ꢀ ꢀ ꢀI1
3.562(5)
3.828(4)
3.905(3)
3.880(4)
3.935(4)
4.074(4)
4.051(5)
3.484(4)
3.449(8)
2.947(3)
3.115(3)
3.018(3)
2.990(3)
3.211(3)
3.197(3)
3.311(3)
–
C3P-H3PBꢀ ꢀ ꢀI1
C6P-H6PAꢀ ꢀ ꢀI1
C2P-H2PBꢀ ꢀ ꢀI2
C4P-H4PBꢀ ꢀ ꢀI2
C24-H24ꢀ ꢀ ꢀI2
O1Eꢀ ꢀ ꢀI2
Appendix A. Supplementary data
C7P-H7PBꢀ ꢀ ꢀO1E
2.560(5)
X-ray crystallographic data of complexes 3ꢀOTf (CCDC
1475100); 5ꢀIꢀEtOH (CCDC 1475101) and 6ꢀ3H2O (CCDC
1475102) (CIF). These data can be obtained free of charge from
the Cambridge Crystallographic Data Centre via www.ccdc.cam.
ac.uk.data-request/cif. Supplementary data associated with this
article can be found, in the online version, at http://dx.doi.org/10.
1016/j.ica.2016.06.019.
6ꢀ3.5H2O
C12-H12Bꢀ ꢀ ꢀOw1
C14-H14Aꢀ ꢀ ꢀOw1
C34-H34ꢀ ꢀ ꢀOw1
C35-H35ꢀ ꢀ ꢀOw1
N13ꢀ ꢀ ꢀOw1
3.634(7)
3.835(8)
3.610(8)
3.532(7)
2.827(7)
3.270(8)
3.384(7)
3.228(8)
3.664(9)
3.537(7)
2.898(6)
3.774(9)
3.601(8)
3.554(9)
3.327(6)
3.286(1)
2.696(4)
2.950(4)
2.684(4)
2.947(4)
C35-H35ꢀ ꢀ ꢀOw2
C14-H14Aꢀ ꢀ ꢀOw2
C24-H24Bꢀ ꢀ ꢀOw2
C31-H31ꢀ ꢀ ꢀOw2
C13-H13Bꢀ ꢀ ꢀOw2
N23ꢀ ꢀ ꢀOw2
2.713(4)
2.762(4)
2.852(5)
2.894(5)
2.805(4)
–
2.811(5)
2.671(5)
2.704(7)
–
References
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C13-H13Bꢀ ꢀ ꢀOw3
C22-H22Aꢀ ꢀ ꢀOw3
C32-H32ꢀ ꢀ ꢀOw3
Br1ꢀ ꢀ ꢀOw3
C25-H25Aꢀ ꢀ ꢀOw4
2.803(9)
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4. Conclusions
In this overview, the synthesis and structural characterization
of a new member of the piano-stool family [RuCpX(L1)(L2)]n+
(X = Clꢁ, Brꢁ, Iꢁ; L1 = PPh3; mTPPMS, L2 = mPTA, PTA; L1 = L2 = PTA,
mPTA) have been presented. The comparison between composition
and water solubility of the family members suggested some rela-
tionship between water solubility and complex composition.
All IR and NMR analyses supported the proposed composition
for the new complexes and indicate that their solid state structure
is maintained in solution.
The combination of PPh3 and mTPPMS phosphanes shows that
the steric and electronic properties cannot be regarded as sepa-
rated factors and both influence the complex water-solubility.
Likewise, the incorporation of two PTA with one mPTA in the
{RuCp} moiety, met with greater success in the complex 7ꢀOTfꢀCl,
the most water-soluble complex tested. The incorporation of two
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Please cite this article in press as: M. Serrano-Ruiz et al., Inorg. Chim. Acta (2016), http://dx.doi.org/10.1016/j.ica.2016.06.019