Synthesis, Spectroscopic and Molecular Studies of Half-Sandwich η6-Arene Ruthenium, Cp Rhodium and Cp Iridium Metal Complexes with Bidentate Ligands

Article abstract of DOI:10.1002/zaac.201400491

The bidentate ligand benzoyl(2-pyridyl)thiourea (L1) was prepared by reaction of benzoyl isothiocyanate with primary amine (2-aminopyridine) but the reaction with secondary amine bis(2-pyridyl)amine, yielded the unexpected product bis(2-pyridyl)benzoylami

Full text of DOI:10.1002/zaac.201400491

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DOI: 10.1002/zaac.201400491
Synthesis, Spectroscopic and Molecular Studies of Half-Sandwich η6-Arene
Ruthenium, Cp* Rhodium and Cp* Iridium Metal Complexes with
Bidentate Ligands
Mahesh Kalidasan,[a] R. Nagarajaprakash,[b] Scott Forbes,[c] Yurij Mozharivskyj,[c] and
Kollipara Mohan Rao*[a]
Keywords: Ruthenium; Arene ligands; Rhodium; Iridium; Dipyridylamine ligands
Abstract. The bidentate ligand benzoyl(2-pyridyl)thiourea (L1) was
prepared by reaction of benzoyl isothiocyanate with primary amine (2-
respectively, were formed by reaction of the ligands L1 and L2 with
precursor complexes [(η6-arene)Ru(μ-Cl)Cl]2 and [Cp*M(μ-Cl)Cl]2
aminopyridine) but the reaction with secondary amine bis(2- (M = Rh, Ir). The cationic complexes were characterized by FT-IR,
1
pyridyl)amine, yielded the unexpected product bis(2-pyridyl)benzo-
UV/Vis, and H-NMR spectroscopy as well as mass spectrometry. X-
ray crystallographic studies of these complexes reveal piano-stool-like
ylamine (L2). Mononuclear complexes of the general formula [(η6-
arene)Ru(L)Cl]+ {where, L = L1, arene = benzene (1); p-cymene (2); arrangements around the metal atoms with six-membered metall-
L = L2, arene = benzene (5); p-cymene (6)} and [Cp*M(L)Cl]+ acycles in which L1 and L2 act as a N,S- and N,N’ chelating ligands,
{where, L = L1, M = Rh (3), Ir (4); L = L2, M = Rh (7), Ir (8)},
respectively.
fields and their metal complexes have been utilized for several
decades and are widely employed in coordination chemistry,
supramolecular chemistry and materials synthesis.[20–25] To the
best of our knowledge there is no report available in the litera-
ture regarding reactions of arene ruthenium and Cp*Rh and
Cp*Ir complexes with benzoyl-(2-pyridyl)thiourea/ bis(2-pyr-
idyl)benzoylamine ligands. Herein, the syntheses of a series
of new mononuclear half-sandwich complexes of arene RuII,
Cp*RhIII and Cp*IrIII with these bidentate ligands are reported.
The ligands used in this study are shown in Scheme 1.
Introduction
The study of half-sandwich arene Ru, Cp*Rh and Cp*Ir
complexes is a versatile subject in organometallic chemistry
due to their unique properties viz. mild reaction conditions re-
quired for synthesis, as well as their high yield, stability and
solubility under aqueous conditions.[1–3] It has been shown that
the nature of the arene, the chelating ligands, and the leaving
group in these complexes strongly influence their chemical and
biological activity.[4,5] The source of metals for all these half-
sandwich complexes are starting dimers, like [(η6-benzene/p-
cymene)RuCl2]2 and [Cp*M(μ-Cl)Cl]2 (M = Rh, Ir), which un-
dergo a rich variety of chemistry via intermediate chloro bridge
cleavage reaction, leading to the formation of a series of neu-
tral and cationic mononuclear complexes.[6–9] Recently, these
complexes have been used catalyst in various organic transfor-
mation reactions[10–15] and attracted considerable interest as a
potential anticancer agent because of their low toxicity, often
good aqueous solubility and their efficacy against platinum
drug resistant tumors.[16–19] Among various bidentate ligands,
2,2’-dipyridylamine (dpa) derivatives and N-substituted pyr-
idine-2-thiourea based ligands have shown interest in various
Scheme 1. Ligands used in this study.
Results and Discussion
* Prof. Dr. K. M. Rao
Fax: +91-364-2550076
Syntheses
E-Mail: mohanrao59@gmail.com
[a] Department of Chemistry
North Eastern Hill University
Shillong 793 022, India
Benzoyl(2-pyridyl)thiourea (L1) is synthesized by reaction
of benzoyl isothiocyanate with 2-aminopyridine in anhydrous
acetone. Similarly, we tried to isolate benzoyl-N,N’-bis(2-pyr-
idyl)thiourea, by reacting a secondary amine such as 2,2-dipyr-
idylamine to benzoyl isothiocyanate, but we isolate unexpected
product N-bis(2-pyridyl)benzoylamine (L2) in quantitative
yield and this conversion is unambiguous.[26] The reaction of
[b] Department of Chemistry
Pondicherry University
Puducherry 605014, India
[c] Department of Chemistry and Chemical Biology
McMaster University
Hamilton, ON L8S 4M1, Canada
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[(η6-arene)Ru(μ-Cl)Cl]2 (arene = benzene and p-cymene) and 1434 cm–1 which is corresponding to the stretching frequencies
[Cp*M(μ-Cl)Cl]2 (M = Rh, Ir) with 1:2 molar equivalents of of C=C and C=N bonds respectively. IR spectra of metal com-
ligand benzoyl(2-pyridyl)thiourea yielded mononuclear com- plexes with ligand L2 have displayed similar pattern of free
plexes [(η6-arene)Ru(NʝS)Cl]PF6 and [Cp*M(NʝS)Cl]PF6 ligand, C=O stretching frequency absorption at around
(Scheme 2). In the case of bis(2-pyridyl) benzoylamine 1690 cm–1 and stretching frequency of C=C and C=N have
and NH4PF6 yield complexes of the type [(η6- shown sharp bands at 1601 cm–1 and 1468 cm–1 respectively.
arene)Ru(NʝN)Cl]PF6 and [Cp*M(NʝN)Cl]PF6 in methanol Upon coordination to metal atoms, the IR stretching frequency
(Scheme 3) with same precursor complexes. These complexes of these groups is shifted to higher frequency region.[27] In
are isolated in very good yield and purified by recrystallization addition, these complexes display very sharp bands at
method. Some of complexes are isolated with a chloride as 841 cm–1 and 558 cm–1 that are corresponding to P-F stretch-
counterion, which improve the solubility in aqueous solvent ing frequency of counterion.[28]
compare to PF6 anion but these complexes are less stability
rather than of PF6 anion complexes. All these complexes are
yellow-orange crystalline solids, resulting as non-hygroscopic,
1H NMR Spectroscopy
1
air-stable. They are highly soluble in acetone, acetonitrile and
DMSO but they are sparingly soluble in methanol, dichloro-
methane and chloroform. The complexes were fully charac-
The H NMR spectrum of the free ligand L1 shows three
resonances for the protons of the phenyl ring at 7.11 to
7.7 ppm and four signals for the protons of the 2-pyridyl ring
are observed at 7.85 to 8.90 ppm, while the NH proton reso-
nances are observed at δ = 9.11 and 8.37 ppm as singlet sig-
nals. In the metal complexes, the NH resonances are observed
low field at δ = 14.25 ppm and 12.70 ppm and the other signals
are shown as similar pattern of free ligand except the signals
are shifted to downfield. The ligand L2 displays three doublets
and four triplets in the range 8.34 to 7.01 ppm that are assigned
to pyridyl and phenyl rings respectively. Upon coordination
with the metal atom, each metal complex has shown seven
signals in the range around 9.00 to 7.30 ppm similar to free
ligand, which is, indicated that formation of mononuclear com-
plexes. For all these complexes, the signals of the coordinated
dipyridyl and phenyl protons are shifted to considerable down-
field as compared to free ligand due to consequence of their
coordination to metal atoms.[29] Besides these signals, com-
plexes 1 and 5 exhibit a singlet signal at δ = 6.35 ppm for the
protons of the benzene ligand. Complexes 2 and 6 exhibit two
doublet signals at δ = 6.30 ppm and 6.02 ppm, which corre-
spond to the aromatic p-cymene ring CH protons, a septet at δ
= 3.04 ppm as well as a doublet observed at δ = 1.35 ppm for
the protons of isopropyl group and a singlet at δ = 2.04 ppm
for the methyl proton of p-cymene ligand, which are shifted
downfield compared to similar complexes. The Cp*Rh com-
plexes 3 and 7 and the Cp*Ir complexes 4 and 8 display singlet
signals at δ = 1.75 and 1.76 ppm due to the Cp* ligand, which
are shifted slightly downfield compared to the starting materi-
als.[7]
1
terized by IR, H NMR, and electronic spectroscopy as well
as mass spectrometry.
Scheme 2. Preparation of metal complexes with ligand L1.
Scheme 3. Preparation of metal complexes with ligand L2.
Mass Spectrometry
IR Spectroscopy
Mass spectrometric studies were carried out for all newly
IR spectra of metal complexes of ligand L1 exhibit vibration synthesized complexes. Parent peaks could be found in ESI
frequency bands at 1313 cm–1 and 1220 cm–1 for the C=S vi- spectra at (m/z) 473.14 (1), 529.15 (2), 532.10 (3) 621.21 (4),
bration whereas the free ligand shows these bands at 1340 cm–1 490.11 (5), 546.16 (6), 548.20 (7) and 638.24 (8). The mass
and 1250 cm–1. This observation indicate that metal is coordi- spectra showed prominent peaks corresponding to the loss of
nated through sulfur and nitrogen. The complexes also display the thiocarboamide ion in complexes 1–4 and the benzoyl
stretching frequency bands at 1670 cm–1 for C=O group and group in complexes 5–8 from molecular ion peaks, but loss of
1570 cm–1, 1434 cm–1 for C=C and C=N bonds.[23b] The IR arene group is not observed which indicate that the stronger
spectrum of the free ligand L2, shows C=O stretching fre- bond with metal ions to these groups. Mass spectra values are
quency at 1660 cm–1, sharp bands at 1584 cm–1 and strongly support the formation of mononuclear complexes.
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Molecular Structures
The molecular structure of mononuclear complexes has been
established by single-crystal X-ray structure analysis. ORTEP
diagrams of the complexes including atom-numbering scheme
are shown in Figure 1, Figure 2, Figure 3, Figure 4, Figure 5,
Figure 6, and Figure 7. Crystallographic and structure refine-
ment parameters for complexes have shown in Table 1. Se-
Figure 4. ORTEP diagram of complex [(η6-benzene)RuCl(L2)]PF6 (5)
with 50% probability thermal ellipsoids. Hydrogen atoms and counter
anion are omitted for clarity.
Figure 1. ORTEP diagram of complex [(η6-p-cymene)RuCl(L1)]Cl (2)
with 50% probability thermal ellipsoids. Hydrogen atoms and counter
anion are omitted for clarity.
Figure 5. ORTEP diagram of complex [(η6-p-cymene)RuCl(L2)]PF6
(6) with 50% probability thermal ellipsoids. Hydrogen atoms and
counter anion are omitted for clarity.
Figure 2. ORTEP diagram of complex [Cp*RhCl(L1)]Cl (3) with 50%
probability thermal ellipsoids. Hydrogen atoms and counter anion are
omitted for clarity.
Figure 3. ORTEP diagram of complex [Cp*IrCl(L1)]Cl (4) with 50%
Figure 6. ORTEP diagram of complex [Cp*RhCl(L2)]PF6 (7) with
probability thermal ellipsoids. Hydrogen atoms, solvent molecules and 50% probability thermal ellipsoids. Hydrogen atoms and counter anion
counter anion are omitted for clarity.
are omitted for clarity.
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¯
clinic space group P1, respectively. All complexes exhibit a
three-legged piano stool geometry with the metal atom coordi-
nated by the arene/Cp* ligand in the chelating k2-N,S mode/
N,N’ mode and a chloride ligand. The chloride anion acts as
counterion in complexes 2–4, and the PF6 anion acts as coun-
terion in complexes 5–8, respectively. The metal atoms in all
complexes adopt a pseudo-octahedral arrangement and the li-
gand is found to coordinate in the bidentate mode to generate
a six-membered metallacycle.
X-ray crystallography studies of all complexes show slightly
different bond lengths and angles between N,S- and N,N’-coor-
dinate complexes. In complexes 2, 3, and 4, only the
N,S-coordination mode like N-substituted 2-pyridine-car-
bothioamide complexes but in contrast to organometallic N-
phenyl-picoliamide complexes where amide switching is de-
tected, probably due to increased stability of the metal to sulfur
bond, as suggested by the HSAB principle.[24] The Ru–S bond
length in complex 2 is 2.360(13) Å, slightly longer than the
other Rh/Ir complexes (2.3386(14) (3), 2.3479(17) Å (4)) but
smaller than reported value [(η6-arene)Ru(NS)Cl]+ (2.3815–
2.3742 Å)[30] and both are within the range of the reported Ru–
S bond lengths (2.354–2.415 Å).[31,32] Complexes 5–8 have
shown that metal bonded through both pyridine nitrogen donor
sites with bond lengths in the range 2.096–2.128 Å. The M–Cl
Figure 7. ORTEP diagram of complex [Cp*IrCl(L2)]PF6 (8) with 50%
probability thermal ellipsoids. Hydrogen atoms and counter anion are
omitted for clarity.
lected bond lengths and bond angles are shown in Table 2 and
the N–H···Cl bonding interactions are shown in Table 3. Com-
plexes 2 and 6 crystallize in the monoclinic space group P21/
c; complexes 3 and 4 crystallize in the orthorhombic space
group Pbca and complexes 5, 7, and 8 crystallized in the tri- bonds are almost equivalent to 2.400 Å which are closely re-
Table 1. Crystallographic and structure refinement parameters for complexes.
[2] ·Cl
[3]·Cl
[4]·Cl·2H2O
[5]·PF6·Hexane
[6]·PF6
[7]·Acetone
Chemical formula
C23H25Cl2N3ORuS C23H26Cl2N3ORhS C23H28Cl2N3O2IrS C23H19ClF16N3OPRu1 C27H27ClF6N3OPRu C27H28ClF6N3OPRh
Formula Mass
563.49
566.35
691.66
634.90
691.00
693.85
Crystal system
a /Å
b /Å
c /Å
α /°
β /°
γ /°
Unit cell volume /Å3
Temperature /K
Space group
Z
Monoclinic
11.8013(4)
11.6159(3)
17.7498(5)
90
92.675(2)
90
2430.54(12)
293(2)
Orthorhombic
16.566(5)
15.216(5)
20.736(6)
90
Orthorhombic
16.5671(5)
15.1811(5)
20.8675(6)
90
90
90
5248.3(3)
293(2)
Pbca
Triclinic
8.5615(17)
12.165(2)
13.108(3)
93.59(3)
92.75(3)
91.54(3)
1360.4(5)
293(2)
Monoclinic
20.5310(6)
15.9530(3)
17.4631(4)
90.00
99.591(2)
90.00
5639.8(2)
293(2)
Triclinic
8.1424(16)
8.5413(17)
21.543(4)
88.94(3)
88.85(3)
86.62(3)
1495.1(5)
293(2)
90
90
5226.6(18)
293(2)
Pbca
¯
¯
P21/c
4
P1
2
P21/c
8
P1
2
16
8
Index ranges
–6 Յ h Ն 15
–14 Յ k Ն 14
–23 Յ l Ն 23
1.540
–15 Յ h Ն 20
–19 Յ k Ն 12
–25 Յ l Ն 13
1.439
–11 Յ h Ն 22
–20 Յ k Ն 15
–26 Յ l Ն 24
1.751
–10 Յ h Ն 10
–14 Յ k Ն 14
–15 Յ l Ն 15
1.550
–25 Յ h Ն 24
–19 Յ k Ն 19
–21 Յ l Ն 21
1.628
–9 Յ h Ն 9
–7 Յ k Ն 11
–28 Յ l Ն 28
1.541
Dc /g·cm–3
μ /mm–1
0.971
0.957
5.400
0.795
0.774
0.777
F(000)
1144
2304
2832
632
2784
700
θ Range
Reflections collected
Independent reflections
28.77, 3.42
10668
5517
26.37, 3.15
16449
5324
28.732, 3.109
17866
6100
24.86, 1.56
30689
4693
26.37, 3.34
30385
9167
24.35, 1.90
28017
5170
[R(int) = 0.0167]
99.7
[R(int) = 0.0229]
99.8
[R(int) = 0.0277]
99.8
[R(int) = 0.0292]
99.6
[R(int) = 0.0337]
99.8
[R(int) = 0.0337]
99.2
Completeness to θ =
25.00°
Data/restraints/parameters 5517/0/290
5324/1/306
1.115
0.0570, wR2 =
0.1903
0.0694, wR2 =
0.2036
1.516, –0.574
6100/0/302
1.052
0.0321, wR2 =
0.0643
0.0546, wR2 =
0.0734
1.069, –0.741
4693/0/325
0.976
0.0385, wR2 = 0.0999 0.0432, wR2 =
0.1052
0.0515, wR2 = 0.1037 0.0609, wR2 =
0.1178
11502/0/728
1.045
5170/0/369
1.156
0.0464, wR2 =
0.1255
0.0562, wR2 =
0.1286
0.888, –0.594
Goodness-of-fit on F2
Final R indices
1.084
0.0273, wR2 =
0.0672
[IϾ2σ (I)]*
R indices (all data)
0.0354, wR2 =
0.0638
0.522, –0.065
Max, Min Δρ /e·Å–3
0.923, –0.430
1.000, –1.006
* Structures were refined on Fo : wR2 = [Σ[w(Fo –Fc ) ]/Σw(Fo2)2]1/2, where w–1 = [Σ(Fo )+(aP)2+bP] and P = [max(Fo , 0)+2Fc ]/3.
2
2
2 2
2
2
2
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Table 2. Selected bond lengths /Å and angles /°.
Complex
2
3
4
5
6
7
8
M(1)–S(1)
M(1)–N(1)
2.360(13)
2.117(4)
2.3386(14)
2.088(4)
2.3479(17)
2.099(5)
2.096(3)
2.100(3)
2.391(12)
2.193(5)
1.682
2.128(3)
2.125(3)
2.397(9)
2.193(5)
1.692
2.122(4)
2.124(4)
2.392(15)
2.153(5)
1.778
2.122(13)
2.112(13)
2.391(4)
2.164(15)
1.790
M(1)–N(3)
M(1)–Cl(1)
M(1)–Cave
M(1)–CNT
2.409(13)
2.204(5)
1.697
2.3863(17)
2.160(6)
1.793
2.3479(17)
2.164(7)
1.796
N(1)–M(1)–S(1)
S(1)–M(1)–Cl(1)
N(1)–M(1)–N(3)
N(1)–M(1)–Cl(1)
N(3)–M(1)–Cl(1)
89.01(11)
86.86(5)
87.18(14)
89.06(6)
87.26(15)
87.93(7)
85.42(11)
83.16(9)
84.81(9)
83.22(11)
83.97(8)
85.32(9)
85.08(06)
86.42(13)
86.62(12)
84.7(5)
84.8(4)
85.5(4)
85.62(11)
87.82(14)
87.26(15)
CNT represents the centroid of the arene/Cp* ring; Cave represents the average bond length centroid of the arene/Cp* ring carbon and metal
atom.
Table 3. N–H···Cl bonding interactions in complexes 2–4.
Complex
Donor–H···Acceptor
D–H
H···A
D···A
D–H···A
2
N(2)–H(2)···Cl(2)i
N(3)–H(3)···Cl(2)i
N(2)–H(2)···Cl(2)
N(3)–H(3)···Cl(2)
N(2)–H(2)···Cl(2)
N(3)–H(3)···Cl(2)
0.62(5)
0.65(7)
0.86
0.86
0.65(8)
0.84(8)
2.59(5)
2.50(7)
2.23
2.64
2.77(7)
2.26(8)
3.173(6)
3.087(5)
3.0650(6)
3.3751(7)
3.373(7)
3.071(7)
157(7)
152(8)
163
145
154(7)
164(7)
3
4
Symmetry transformations used to generate equivalent atoms: i = 1–x, –1/2+y, 1/2–z.
lated to previous reported half-sandwich arene ruthenium com-
Complex 5 form dimers via CH/Cl and weak CH/Cl and
plexes with bis(2-pyridyl)benzoylamine,[33] 3-(di-2-pyridyl- CH/O intermolecular interactions with bond lengths 2.855,
aminomethyl) benzamide,[34] and similar systems of 2.866, and 2.511 Å by adopting dimeric units of R2 (8),
[Cp*Ir(NʝN)Cl]+ where, NʝN is bis(2-pyridyl) benzylamine, R2 (14), R2 (6) respectively which are stabilized by crystal
2
2
3
3-(di-2-pyridylaminomethyl)benzamide ligand[33–35] and other packing (Figure 8). Additionally, there is an interaction of the
dipyridylamine based ligand.[34] The bite angle of metal with pyridyl rings (C12/C13/C14/C15) in the molecule by π···π in-
ligand is around 85° which are normal and consistent with k2- teractions with the neighboring pyridyl molecule (C12/C13/
coordination of ligand. The bond angle of metal with ligand C14/C15) with a bond length of 3.307 Å.[38]. Furthermore this
and chloride atom is also similar to bite angle that is nearly complex has shown a mutual intermolecular C–H/Cl and C–
90° and is evidence for “piano stool” geometry.
H/π bonding network resulting in the formation of a 2D sheet-
Crystal structure analyses of the metal complexes have re- like arrangement consisting of various dimeric units. Some
vealed the presence of extensive inter-/intramolecular C–H/X interesting supramolecular interactions like C–H/Cl and C–H/
(O, Cl and F) and C–H/π interactions, as well as π···π interac- π interactions are observed in the solid state packing of com-
tions. These types of interaction play significant role in the
building of huge supra-molecular motifs and dominant role in
stabilizing the stacking of molecules.[36,37] Weak interactions
like S···O, C–H/Cl and C–H/π interactions, or π···π interactions
were observed in the solid state packing of the complexes.
Analyses of complexes 2–4 revealed five-membered intramo-
lecular O···S interactions with bond lengths 2.886, 2.849, and
2.824 Å, respectively. But these O···S interactions differ from
the free ligand of benzoyl(2-pyridyl)thiourea, which shows
five-membered intramolecular N–H···O hydrogen bonding in-
teraction. The counterion of chloride atom in the complexes
involves with thiourea unit in the formation of the resulting
intermolecular N–H···Cl hydrogen-bonded network and N–
H···Cl hydrogen bonding have shown in Table 3. The N–H···Cl
contact typically has a separation of 3.375–3.065 Å, the H···Cl
distances are in the range 2.23–2.77 Å, and the N–H···Cl
angles are in the range 145–164°, which is in the general range
of strong N–H···Cl bonds.[23]
Figure 8. Portions of the packing diagram of complex 5 (a). C–H···Cl
interaction; (b). C–H···Cl and π···π interaction; (c). C–H···O interaction
along c axis.
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Figure 9. Portions of packing diagram of showing C–H···Cl and C–H···π interaction along b axis in (a) Complex 7, b) Complex 8.
Figure 10. UV/Vis spectra of all complexes in the range 200–650 nm.
plexes 7 and 8 (Figure 9). Unlikely, complexes 7 and 8 form transition (MLCT) arising from the excitation of electrons
similar kinds of two-dimensional networks via C–H/Cl and C– from the metal t2g level to the empty molecular orbitals derived
H/π short contacts. Two molecules interact via C–H/π short from the π* level of the ligands.
contacts to form a dimeric pair and this dimeric pair is linked
via mutual C–H/Cl short contacts to form a 2D sheet along b
axis with bond lengths 2.827 and 2.886 Å (7), and 2.849 and
Conclusions
A new series of arene ruthenium and Cp*Rh and Cp*Ir
complexes with benzoyl(2-pyridyl)thiourea (L1)/bis(2-
pyridyl)benzoylamine (L2) ligands was synthesized. All com-
plexes were obtained in high yield, were soluble in polar sol-
2.760 Å (8), respectively. Complex 8 shows an interesting ar-
rangement in crystal packing of one PF6 anion molecule oc-
cupy into cavity of chain which is two-dimensional networks
via C–H/Cl and C–H/π short contacts. All the interactions are
intermolecular in nature and the short contact distances are
comparable to the literature reports.[39–41]
1
vents, and remarkably stable in air. IR and H NMR spectro-
scopic studies of the complexes strongly supported the forma-
tion of the products. X-ray crystallographic studies of the com-
plexes established the coordination of the ligand to the metal
atoms in bidentate mode. The binding mode of metal with li-
gands L1 is NʝS mode while L2 NʝN mode. The synthesis
of dinuclear complexes with L1 by using other binding sites
like NN’ or NO was unsuccessful. Moreover, metal complexes
have been found to form inter-/intramolecular interactions such
as O–S as well as CH···Cl, CH···π, or π···π interactions.
UV/Vis Spectroscopy
UV/Vis spectra of complexes are recorded in acetonitrile at
approx. 10–4 m concentration in the range 200–800 nm and the
spectra of all complexes are shown in Figure 10. The UV/Vis
spectra of complexes exhibit intense ligand-localized or intrali-
gand π–π* transitions in the UV region and metal to ligand
charge transfer (MLCT) of the dπ(M)–π*(L) band in the vis-
ible region.[42] The UV/Vis spectra of all complexes show two
bands in the region 446–230 nm. The high intense absorption
bands at approximately 230–320 nm are assigned to π–π*/n–
π* transitions while the low intensity bands observed around
Experimental Section
Materials and Methods
RuCl3•nH2O, RhCl3•nH2O, IrCl3•nH2O (Arora Matthey Limited), α-
406–446 nm are assigned to the metal to ligand charge transfer Phellandrene, Benzoylchloride (Merck) and 1,4-cyclohexadiene,
Z. Anorg. Allg. Chem. 0000, 0–0
6
© 0000 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Journal of Inorganic and General Chemistry
www.zaac.wiley-vch.de
ARTICLE
Zeitschrift für anorganische und allgemeine Chemie
1,2,3,4,5-pentamethylcyclopentadiene, 2-aminopyridine, 2,2-dipyr-
peak. UV/Vis: λmax nm (ε /10–4 –1 cm–1): 255(0.49), 280(0.42),
m
idylamine (Aldrich) were purchased and used as received. Solvents
were purified and dried according to standard procedures.[43] The ex-
periments were performed under normal conditions. The starting pre-
cursor metal complexes [(η6-benzene)Ru(μ-Cl)Cl]2, [(η6-p-
cymene)Ru(μ-Cl)Cl]2[44,45] and [Cp*M(μ-Cl)Cl]2 (M = Rh, Ir)[46] were
prepared according to the literature methods. The ligand benzoyl-(2-
pyridyl) thiourea, bis(2-pyridyl)benzoylamine were prepared to modify
the reported procedure.[47] 1H NMR spectra were recorded with a
Bruker Avance II 400 MHz. Infrared spectra were recorded as KBr
pellets with a Perkin- Elmer 983 spectrophotometer. Mass spectra were
obtained from Water ZQ-4000 mass spectrometer by ESI method in
positive mode. Elemental analyses were performed with a Perkin- El-
mer-2400 CH/N analyzer. Absorption spectra were obtained at room
temperature using a Perkin- Elmer Lambda 25 UV/Vis spectrophotom-
eter.
392(0.04); Elemental Anal. for C19H17N3OSRuClPF6 (616.9): C
36.99 (calcd. 40.15); H 2.78 (2.95); N 6.81 (6.91).
[(η6-p-cymene)Ru(L1)Cl]PF6 (2): Yield 97 mg (72%). IR (KBr
(cm–1)): ν(NH) 3400 m, ν(CH) 2963 m, ν(C=O) 1714 s, ν(C=C, C=N)
1600–1477 vs, ν(C=S, C–N) 1312–1217 s, νbent(CH) 780–709 m, ν(P–
1
F) 841, 554 s. H NMR (400 MHz, CDCl3, 25 °C): δ = 14.35 (s, 1 H,
NH), 12.82 (s, 1 H, NH), 8.75 (d, JH,H = 5.50 Hz, 1 H, py ring), 7.70
(d, JH,H = 4.75 Hz, 1 H, py ring), 7.53 (d, JH,H = 5.25 Hz, 2 H, ph
ring), 7.49 (t, 1 H, py ring), 7.46 (t, 2 H, ph ring), 7.34 (t, 1 H, py
ring), 7.12 (t, 1 H, ph ring), 6.32 (d, JH,H = 4.00 Hz, 2 H, ph ring),
6.12 (d, JH,H = 4.00 Hz, 2 H, ph ring), 3.06 (sep, 1 H, Ar(p– Cy)), 2.06
(s, 3 H, CH3Ar(p– Cy)), 1.37 (d, JH,H = 4.50 Hz, 6 H, CH3 Ar(p– Cy)),
1.25 (d, JH,H = 4.25 Hz, 6 H, CH3Ar(p– Cy)). ESI-MS: 529.15 [M+]
peak, 492.12 [M+ – Cl] peak, 329.00 [(p-cy)Ru(2-py)+] peak. UV/Vis:
λmax nm (ε /10–4 –1 cm–1): 257(0.46), 282(0.39), 403(0.03); Elemen-
m
tal Anal. for C23H25N3OSRuClPF6 (673.0): C 41.05 (calcd. 41.24); H
3.74 (3.87); N 6.24 (6.43).
Single-Crystal X-ray Structure Analyses
[Cp*Rh(L1)Cl]PF6 (3): Yield 92 mg (68%). IR (KBr (cm–1)): ν(NH)
3314 m, ν(CH) 2970 m, ν(C=O) 1706 s, ν(C=C, C=N) 1598–1476 vs,
ν(C=S, C–N) 1318–1215 s, νbent(CH) 782–712 m, ν(P–F) 845, 554 s.
1H NMR (400 MHz, CDCl3, 25 °C): δ = 14.23 (s, 1 H, NH), 12.71(s,
The orange crystals of complexes 2–7 were obtained by slow diffusion
of hexane into acetone solution and yellow crystals of complex 8 were
obtained by slow evaporation of acetonitrile of the corresponding com-
plex. Single crystal X-ray diffraction measurements were carried out
on an Xcalibur, Eos, Gemini and STOE IPDSII diffractometer. Single
crystals picked up from the samples were analyzed on a STOE IPDSII
diffractometer using Mo Kα radiation in the whole reciprocal sphere.
A numerical absorption correction was based on the crystal shape orig-
inally determined by optical face indexing but later optimized against
equivalent reflections using the STOE X-Shape software.[48] Crystal
structures were determined and solved using the SHELX software.[49]
PLATON SQUEEZE was applied to the X-ray single crystal data to
remove a highly disordered solvent which appeared to be “hexane”
(5), “acetone“ (7) and “acetonitrile” (8).[50] The crystal structure of
complex 8 could not be properly solved due to the residual electron
densities are extremely high Ͼ 5.5; we have presented the data here
to establish only the structure and composition of the molecule. In
crystal structure of complex 2, chlorine atoms Cl2, Cl3 and Cl4 were
refined with partial occupancy such that add up to 100%. Crystallo-
graphic details are summarized in Table 1 and selected bond lengths
and bond angles and given in Table 2. Figure 1, Figure 2, Figure 3,
Figure 4, Figure 5, Figure 6, and Figure 7 were drawn with ORTEP–
3[51] and Figure 8 and Figure 9 were drawn with MERCURY.
1 H, NH), 8.67 (d, JH,H = 3.25 Hz, 1 H, py ring), 8.32 (d, JH,H
=
4.75 Hz, 2 H, ph ring), 7.88 (d, JH,H = 5.00 Hz, 1 H, py ring), 7.83 (t,
1 H, py ring), 7.50 (m, 3 H, ph ring), 7.28 (t, 1 H, py ring), 1.56 (s,
15 H, Cp* ring). ESI-MS: 532.10 [M+] peak, 494.13 [M+ – Cl] peak,
331.02 [Cp*Rh(2-py)+] peak. UV/Vis: λmax nm (ε /10–4
m
–1 cm–1):
255(0.45),
295(0.33),
411(0.04);
Elemental
Anal. for
C23H26N3OSRhClPF6 (675.8): C 40.87 (calcd. 41.02); H 3.88 (3.97);
N 6.22 (6.41).
[Cp*Ir(L1)Cl]PF6 (4): Yield 98 mg (64%). IR (KBr (cm–1)): ν(NH)
3318 m, ν(CH) 2918 m, ν(C=O) 1707 s, ν(C=C, C=N) 1616–1477 vs,
ν(C=S, C–N) 1310–1229 s, νbent(CH) 781–712 m, ν(P–F) 843, 558 s.
1H NMR (400 MHz, CDCl3, 25 °C): δ = 13.99 (s, 1 H, NH), 12.68 (s,
1 H, NH), 8.58 (d, JH,H = 3.25 Hz, 1 H, py ring), 8.31 (d, JH,H
=
4.50 Hz, 2 H, ph ring), 7.90 (t, 1 H, py ring), 7.78 (m, 2 H, ph ring),
7.56 (d, JH,H = 4.25 Hz, 2 H, py ring), 7.49 (t, 1 H, py ring), 1.55 (s,
15 H, Cp* ring). ESI-MS: 621.21 [M+] peak, 584.23 [M+ – Cl] peak,
420.11 [Cp*Ir(2-py)+] peak. UV/Vis: λmax nm (ε/ 10–4
m
–1 cm–1):
255(0.57),
284(0.56),
396(0.08);
Elemental
Anal. for
C23H26N3OSIrClPF6 (765.1): C 36.10 (calcd. 36.28); H 3.42 (3.57); N
5.49 (5.63).
Syntheses of Metal Complexes 1–4
A mixture of the metal precursor [(η6-arene)Ru(μ-Cl)Cl]2 or [Cp*M(μ-
Cl)Cl]2 (0.1 mmol), benzoyl(2-pyridyl)thiourea (0.2 mmol) and 2.5
equivalents of NH4PF6 was dissolved in methanol (20 mL) and stirred A mixture of the metal precursor [(η6-arene)Ru(μ-Cl)Cl]2 or [Cp*M(μ-
Syntheses of Metal Complexes 5–8
at room temperature for 4 h. A yellow colored precipitate was formed Cl)Cl]2 (0.1 mmol), bis(2-pyridyl)benzoylamine (0.2 mmol) and 2.5
upon evaporation of methanol solvent by rotary evaporator. The pre-
cipitate was washed with methanol and diethyl ether (3 ϫ 10 mL) and
dried in vacuo.
equivalents of NH4PF6 was dissolved in methanol (20 mL) and stirred
at room temperature for 8 h. Yellow colored precipitate was formed.
The precipitate was washed with methanol and diethyl ether (3 ϫ
10 mL) and dried in vacuo.
[(η6-benzene)Ru(L1)Cl]PF6 (1): Yield 85 mg (69%). IR (KBr
(cm–1)): ν(NH) 3386 m, ν(CH) 3056 m, ν(C=O) 1699 s, ν(C=C, C=N) [(η6-benzene)Ru(L2)Cl]PF6 (5): Yield 100 mg (78%). IR (KBr
1598–1479 vs, ν(C=S, C–N) 1313–1229 s, νbent(CH) 773–706 m, ν(P–
(cm–1)): ν(CH) 3091 m, ν(C=O) 1693 s, ν(C=C, C=N) 1601–1469 vs,
F) 845, 555 s. H NMR (400 MHz, CDCl3, 25 °C): δ = 14.33 (s, 1 H, ν(C–N) 1329–1273 s, νbent(CH) 779–708 m, ν(P–F) 840, 558 s. 1H
1
NH), 12.81 (s, 1 H, NH), 8.72 (d, 1 H, J(H,H) = 5.25, py ring), 7.65
(d, JH,H = 4.75 Hz, 1 H, py ring), 7.52 (d, JH,H = 5.50 Hz, 2 H, ph
NMR (400 MHz, [d6]-Acetone, 25 °C): δ = 9.20 (d, JH,H = 3.25 Hz, 2
H, py ring), 8.11 (t, 2 H, py ring), 7.88 (d, JH,H = 5.25 Hz, 2 H, py
ring), 7.50 (t, 1 H, py ring), 7.47 (t, 2 H, ph ring), 7.35 (t, 1 H, py ring), 7.65 (t, 2 H, py ring), 7.57 (t, 1 H, ph ring), 7.53 (d, JH,H
ring), 7.11 (t, 1 H, ph ring), 6.32 (s, 6 H, benzene ring). ESI-MS: 4.50 Hz, 2 H, ph ring), 7.47 (t, 2 H, ph ring), 6.35 (s, 6 H, benzene
473.14 [M+] peak, 436.20 [M+ – Cl] peak, 274.08 [(ben)Ru(2-py)+] ring). ESI-MS: 490.11 [M+] peak, 455.13 [M+ – Cl] peak, 350.04
=
Z. Anorg. Allg. Chem. 0000, 0–0
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© 0000 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Journal of Inorganic and General Chemistry
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ARTICLE
Zeitschrift für anorganische und allgemeine Chemie
[(ben)Ru(dpy)+] peak. UV/Vis: λmax nm (ε /10–4 –1 cm–1): 275(0.20);
m
Elemental Anal. for C23H19N3ORuClPF6 (634.9): C 43.51 (calcd.
43.88); H 3.02 (3.30); N 6.62 (6.91).
[3] E. L. Muetterties, J. R. Bleeke, E. J. Wucherer, T. Albright, Chem.
Rev. 1982, 82, 499–525.
[4] A. Habtemariam, M. Melchart, R. Fernandez, S. Parsons, I. D. H.
Oswald, A. Parkin, F. P. A. Fabbiani, J. E. Davidson, A. Dawson,
R. E. Aird, D. I. Jodrell, P. J. Sadler, J. Med. Chem. 2006, 49,
6858–6868.
[5] F. Linares, E. Q. Procopio, M. A. Galindo, M. A. Romero,
J. A. R. Navarro, E. Barea, CrystEngComm 2010, 12, 2343–2346.
[6] J. Canivet, G. Suss-Fink, Green Chem. 2007, 9, 391–397.
[7] G. Gupta, K. T. Prasad, B. Das, G. P. A. Yap, K. M. Rao, J. Or-
ganomet. Chem. 2009, 694, 2618–2627.
[(η6-p-cymene)Ru(L2)Cl]PF6 (6): Yield 110 mg (79%). IR (KBr
(cm–1)): ν(CH) 2975 m, ν(C=O) 1687 s, ν(C=C, C=N) 1601–1440 vs,
ν(C–N) 1327–1280 s, νbent(CH) 780–709 m, ν(P–F) 841, 558 s. 1H
NMR (400 MHz, [d6]-Acetone, 25 °C): δ = 9.10 (d, JH,H = 3.25 Hz, 2
H, py ring), 8.11 (t, 2 H, py ring), 7.90 (d, JH,H = 5.00 Hz, 2 H, py
ring), 7.67 (t, 2 H, py ring), 7.67 (t, 1 H, ph ring), 7.54 (d, JH,H
=
4.50 Hz, 2 H, ph ring), 7.48 (t, 2 H, ph ring), 6.30 (d, JH,H = 4.00 Hz,
2 H, ph ring), 6.02 (d, JH,H = 4.00 Hz, 2 H, ph ring), 3.04 (sep, 1 H,
Ar(p– Cy)), 2.04 (s, 3 H, CH3Ar(p– Cy)), 1.35 (d, JH,H = 4.25 Hz, 6 H,
CH3Ar(p– Cy)), 1.24 (d, JH,H = 4.25 Hz, 6 H, CH3 Ar(p–Cy)). ESI-MS:
546.16 [M+] peak, 510.09 [M+ – Cl] peak, 406.10 [(p-cy)Ru(dpy)+]
[8] F. Marchetti, C. Pettinari, R. Pettinari, A. Cerquetella, A. Cingol-
ani, E. J. Chan, K. Kozawa, B. W. Skelton, A. H. White, R.
Wanke, M. L. Kuznetsov, L. M. D. R. S. Martins, A. J. L. Pom-
beiro, Inorg. Chem. 2007, 46, 8245–8257.
[9] S. Mirtschin, A. S. Turski, R. Scopelliti, A. H. Velders, K. Seve-
rin, J. Am. Chem. Soc. 2010, 132, 14004–14005.
[10] P. Kumar, R. K. Gupta, D. S. Pandey, Chem. Soc. Re. 2014, 43,
707–733.
[11] D. L. Davies, J. Fawcett, S. A. Garratt, D. R. Russell, Organome-
tallics 2001, 20, 3029–3034.
peak. UV/Vis: λmax nm (ε /10–4 –1 cm–1): 269(0.22); Elemental
m
Anal. for C27H27N3ORuClPF6 (691.0): C 46.93 (calcd. 47.28); H 3.94
(4.21); N 6.08 (6.33).
[Cp*Rh(L2)Cl]PF6 (7): Yield 112 mg (80%). IR (KBr (cm–1)):
ν(CH) 3120 m, ν(C=O) 1676 s, ν(C=C, C=N) 1600–1469 vs, ν(C–
[12] V. Cadierno, J. Francos, J. Gimeno, Green Chem. 2010, 12, 135–
143.
[13] L. Jafarpour, S. P. Nolan, J. Organomet. Chem. 2001, 617–618,
1
N) 1326–1277 s, νbent(CH) 783–715 m, ν(P–F) 839, 558 s. H NMR
17–27.
(400 MHz, [d6]-Acetone, 25 °C): δ = 8.88 (d, JH,H = 3.25 Hz, 2 H, py
ring), 8.06 (t, 2 H, py ring), 7.83 (d, JH,H = 5.25 Hz, 2 H, py ring),
7.66 (t, 2 H, py ring), 7.53 (t, 1 H, ph ring), 7.39 (t, 2 H, ph ring),
7.31 (d, JH,H = 4.75 Hz, 2 H, ph ring),1.75 (s, 15 H, Cp* ring).
[14] R. Noyori, S. Hashiguchi, Acc. Chem. Res. 1997, 30, 97–102.
[15] a) R. J. Lundgren, M. A. Rankin, R. McDonald, G. Schatte, M.
Stradiotto, Angew. Chem. Int. Ed. 2007, 46, 4732–4735; b) T. L.
Church, P. G. Anderson, Coord. Chem. Rev. 2008, 252, 513–531.
[16] M. Gras, B. Therrien, G. Süss-Fink, A. Casini, F. Edafe, P. J.
Dyson, J. Organomet. Chem. 2010, 695, 1119–1125.
[17] a) K. D. Camm, A. E. Sokkary, A. L. Gott, P. G. Stockley, T. Be-
lyaeva, P. C. McGowan, Dalton Trans. 2009, 10914–10925; b) W.
Kandioller, E. Balsano, S. M. Meier, U. Jungwirth, S. Goschl, A.
Roller, M. A. Jakupec, W. Berger, B. K. Keppler, C. G. Hartinger,
Chem. Commun. 2013, 49, 3348–3350.
ESI-MS: 548.20 [M+] peak, 512.20 [M+
–
m
Cl] peak, 408.15
–1 cm–1): 230(0.35),
[Cp*Rh(dpy)+] peak. UV/Vis: λmax nm (ε /10–4
273(0.18), 385(0.02); Elemental Anal. for C27H28N3ORhClPF6
(693.8): C 46.74 (calcd. 46.98); H 4.07 (4.32); N 6.06 (6.31).
[Cp*Ir(L2)Cl]PF6 (8): Yield 140 mg (87%). IR (KBr (cm–1)): ν(CH)
3122 m, ν(C=O) 1680 s, ν(C=C, C=N) 1603–1469 vs, ν(C–N) 1329–
1275 s, νbent(CH) 782–714 m, ν(P–F) 838, 558 s. 1H NMR (400 MHz, [18] a) Z. Liu, P. J. Sadler, Acc. Chem. Res. 2014, 47, 1174–1185; b)
C. Streu, L. Feng, P. J. Carroll, J. Maksimoska, R. Marmorstein,
E. Meggers, Inorg. Chim. Acta 2011, 377, 34–41.
[19] F. W. Monnard, T. Heinisch, E. S. Nogueira, T. Schirmer, T. R.
Ward, Chem. Commun. 2011, 47, 8238–8140.
[d6]-Acetone, 25 °C): δ = 8.98 (d, JH,H = 3.50 Hz, 2 H, py ring), 8.17
(t, 2 H, py ring), 8.01 (d, JH,H = 5.00 Hz, 2 H, py ring), 7.74 (t, 2 H,
py ring), 7.61 (t, 1 H, ph ring), 7.48 (t, 2 H, ph ring), 7.36 (d, JH,H
=
4.75 Hz, 2 H, ph ring), 1.76 (s, 15 H, Cp* ring). ESI-MS: 638.24 [M+]
peak, 602.24 [M+ – Cl] peak, 498.21 [Cp*Ir(dpy)+] peak. UV/Vis: λmax
[20] E. C. Constable, P. J. Steel, Coord. Chem. Rev. 1989, 93, 205–
223.
nm (ε /10–4 –1 cm–1): 273(0.27), 376(0.02); Elemental Anal. for
m
[21] a) C. J. Sumby, Coord. Chem. Rev. 2011, 255, 1937–1967; b) P. J.
Steel, C. J. Sumby, Dalton Trans. 2003, 4505–4515.
[22] a) B. Bantu, K. Wurst, M. R. Buchmeiser, J. Organomet. Chem.
2007, 692, 5272–5278; b) C. J. Sumby, P. J. Steel, Polyhedron
2007, 26, 5370–5381.
[23] a) D. Che, G. Li, Z. Yu, D. Zou, C. Du, Inorg. Chem. Commun.
2000, 3, 537–540; b) W. Kaminsky, K. I. Goldberg, D. X. West,
J. Mol. Struct. 2002, 605, 9–15.
[24] a) S. M. Meier, M. Hanif, Z. Adhireksan, V. Pichler, M. Novak,
E. Jirkovsky, M. A. Jakupec, V. B. Arion, C. A. Davey, B. K.
Keppler, C. G. Hartinger, Chem. Sci. 2013, 4, 1837–1846; b) P.
Haquette, B. Talbi, L. Barilleau, N. Madern, C. Fossec, M. Sal-
main, Org. Biomol. Chem. 2011, 9, 5720–5727.
C27H28N3OIrClPF6 (783.1): C 41.41 (calcd. 41.58); H 3.60 (3.72); N
5.37 (5.51).
CCDC-1021972 (2), -1021973 (3), -1021974 (4), -1021975 (5),
-102657 (6), -1026576 (7), and -1021976 (8) contain the supplemen-
tary crystallographic data for this paper. These data can be obtained
free of charge via www.ccdc.cam.ac.uk/data_request/cif, by E-mailing
data_request@ccdc.cam.ac.uk, or by contacting The Cambridge Crys-
tallographic Data Centre, 12, Union Road, Cambridge CB2 1EZ, UK;
Fax: +44-1223-336033.
[25] A. Chevalley, M. Salmain, Chem. Commun. 2012, 48, 11984–
11986.
Acknowledgments
[26] a) I. J. Bruno, J. C. Cole, P. R. Edgington, M. Kessler, C. F. Mac-
rae, P. McCabe, J. Pearson, R. Taylor, Acta Crystallogr., Sect. B
2002, 58, 389–397; b) H. V. D. Poel, G. V. Koten, K. Vrieze, In-
org. Chem. 1980, 19, 1145–1151.
[27] L. Bellamy, Infrared Spectra of Complex Molecules, Methuen,
London, 1954, p. 175.
Mahesh K thanks UGC, New Delhi for providing financial assistance
in the form of University Fellowship (UGC-RFSMS). K. M. Rao grate-
fully acknowledges financial support from CSIR, New Delhi, through
the Research grants No. 01(2493)/11/EMR-II.
[28] K. Nakamoto, Infrared and Raman Spectra of Inorganic and Co-
ordination Complexes, Part A, 6th ed., John Wiley & Sons, Ho-
boken, 2009, pp. 221–227.
[29] G. Gupta, S. Gloria, S. L. Nongbri, B. Therrien, K. M. Rao, J.
Organomet. Chem. 2011, 696, 2014–2022.
References
[1] P. Kumar, R. K. Gupta, D. S. Pandey, Chem. Soc. Rev. 2014, 43,
707–733.
[2] B. Therrien, Coord. Chem. Rev. 2009, 253, 493–519.
[30] P. Singh, A. K. Singh, Eur. J. Inorg. Chem. 2010, 4187–4195.
Z. Anorg. Allg. Chem. 0000, 0–0
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© 0000 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

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ARTICLE
Zeitschrift für anorganische und allgemeine Chemie
[31] V. A. Rao, R. Pallepogu, Z. Y. Zhou, K. M. Rao, Inorg. Chim. [42] E. Sindhuja, R. Ramesh, Y. Liu, Dalton Trans. 2012, 41, 5351–
Acta 2012, 387, 37–44.
5361.
[32] M. Ulaganatha Raja, R. Ramesh, J. Organomet. Chem. 2012, 699,
5–11.
[33] a) G. Gupta, S. Park, S. S. Lee, J. Kim, Z. Anorg. Allg. Chem.
2011, 637, 1516–1521; b) P. Kumar, A. K. Singh, R. Pandey, P. Z.
Li, S. K. Singh, Q. Xu, D. S. Pandey, J. Organomet. Chem. 2010,
695, 2205–2212.
[43] D. D. Perrin, W. L. F. Armarego, Purification of Laboratory
Chemicals, f4th ed., Butterworths-Heinemann, London, 1996.
[44] M. A. Bennett, T. N. Huang, T. W. Matheson, A. K. Smith, Inorg.
Synth. 1982, 21, 74–78.
[45] a) M. A. Bennett, T. W. Matheson, G. B. Robertson, A. K. Smith,
P. A. Tucker, Inorg. Chem. 1980, 19, 1014–1021; b) M. A.
Bennett, A. K. Smith, J. Chem. Soc., Dalton Trans. 1974, 233–
241.
[46] a) J. W. Kang, K. Moseley, P. M. Maitlis, J. Am. Chem. Soc. 1969,
91, 5970–5977; b) R. G. Ball, W. A. G. Graham, D. M. Heinekey,
J. K. Hoyano, A. D. McMaster, B. M. Mattson, S. T. Michel, In-
org. Chem. 1990, 29, 2023–2025; c) C. White, A. Yates, P. M.
Maitlis, Inorg. Synth. 1992, 29, 228–234.
[47] a) Y. F. Yuan, L. Y. Zhang, J. P. Cheng, J. T. Wang, Trans. Met.
Chem. 1997, 22, 281–283; b) D. Lee, B. Kim, Y. Oh, M. S. Lah,
W. Chang, Bull. Korean Chem. Soc. 1996, 17, 836–839.
[48] STOE X-Shape, STOE & Cie GmbH, Darmstadt, Germany, 2004.
[49] G. M. Sheldrick, SHELXL, University of Göttingen, Germany,
1997.
[34] S. Gloria, P. Wang, K. M. Rao, Z. Anorg. Allg. Chem. 2012,
638,634–640.
[35] C. Romain, S. Gaillard, M. K. Elmkaddem, L. Toupet, C. Fisch-
meister, C. M. Thomas, J. L. Renaud, Organometallics 2010, 29,
1992–1995.
[36] H. Mishra, R. Mukherjee, J. Organomet. Chem. 2010, 695, 1753–
1560.
[37] F. Tellez, A. Cruz, H. L. Sandoval, I. R. Garcıa, M. Gayosso,
R. N. C. Sierra, B. P. Michel, H. Noth, A. F. Parra, R. Contreras,
Eur. J. Org. Chem. 2004, 4203–4214.
[38] G. Gupta, S. Gloria, B. Therrien, B. Das, K. M. Rao, J. Or-
ganomet. Chem. 2011, 696, 702–708.
[39] C. Q. Wan, J. Han, T. C. W. Mak, New J. Chem. 2009, 33, 707–
712.
[40] R. Nagarajaprakash, B. Ramakrishna, K. Mahesh, S. M. Mobin,
B. Manimaran, Organometallics 2013, 32, 7292–7296.
[41] C. D. Nunes, M. Pillinger, A. Hazell, J. Jepsen, T. M. Santos, J.
Madureira, A. D. Lopes, I. S. Goncalves, Polyhedron 2003, 22,
2799–2807.
[50] A. L. Spek, J. Appl. Crystallogr. 2003, 36, 7–13.
[51] L. J. Farrugia, J. Appl. Crystallogr. 1997, 30, 565–566.
Received: October 26, 2014
Published Online: ᭿
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© 0000 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Journal of Inorganic and General Chemistry
www.zaac.wiley-vch.de
ARTICLE
Zeitschrift für anorganische und allgemeine Chemie
M. Kalidasan, R. Nagarajaprakash, S. Forbes,
Yu. Mozharivskyj, K. M. Rao* ........................................ 1–10
Synthesis, Spectroscopic and Molecular Studies of Half-Sand-
wich η6-Arene Ruthenium, Cp* Rhodium and Cp* Iridium
Metal Complexes with Bidentate Ligands
Z. Anorg. Allg. Chem. 0000, 0–0
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© 0000 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim