Synthesis and characterization of molecular rectangles of half-sandwich p-cymene ruthenium complexes bearing oxamidato ligands

Article abstract of DOI:10.1039/b909357e

A series of binuclear half-sandwich p-cymene ruthenium complexes bearing oxamidato ligands [(p-cymene)₂Ru₂(μ-N,N′- bis(aryl)oxamidato)Cl₂] (1-3) was synthesized by the reactions of the lithium salts of oxamide with [(p-cym

Full text of DOI:10.1039/b909357e

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www.rsc.org/dalton | Dalton Transactions
Synthesis and characterization of molecular rectangles of half-sandwich
p-cymene ruthenium complexes bearing oxamidato ligands†
Wan-Zheng Zhang, Ying-Feng Han, Yue-Jian Lin and Guo-Xin Jin*
Received 12th May 2009, Accepted 14th August 2009
First published as an Advance Article on the web 28th August 2009
DOI: 10.1039/b909357e
A series of binuclear half-sandwich p-cymene ruthenium complexes bearing oxamidato ligands
[(p-cymene)2Ru2(m-N,N ¢-bis(aryl)oxamidato)Cl2] (1–3) was synthesized by the reactions of the lithium
salts of oxamide with [(p-cymene)RuCl2]2, respectively. Treatment of the binuclear complexes (1–3) with
bidentate ligands such as 4,4¢-bipyridine (4,4¢-bpy) and trans-1,2-bis(4-pyridyl)ethylene (bpe) in the
presence of AgOTf (OTf = CF3SO3) gave the corresponding tetranuclear complexes generally
formulated as [(p-cymene)4Ru4(m-N,N ¢- bis(aryl)oxamidato)2(m-4,4¢-bpy)2](OTf)4 (4a–c) and
[(p-cymene)4Ru4(m-N,N¢-bis(aryl)oxamidato)2(m-bpe)2](OTf)4 (5a–c) in high yields. All compounds
(1–3, 4a–5c) have been characterized by NMR and IR spectra and elemental analyses. The molecular
structures of 1, 4a and 5a have been determined by single-crystal X-ray analyses. The molecular
structures of tetranuclear complexes 4a and 5a showed that two binuclear fragments as building blocks
˚
were connected by 4,4¢-bpy or bpe to construct a rectangular cavity with the dimensions 5.57 ¥ 11.28 A
˚
(4a) and 5.56 ¥ 13.65 A (5a).
of which show special ability in ion affinity and selectivity.11 In our
Introduction
group, a series of tetra-, hexa- and octanuclear complexes with
In the past decades, the design and synthesis of supramolecular
half-sandwich Ir, Rh, and Ru fragments have been synthesized
polygons and polyhedra containing metal building blocks have
successfully by the combination of binuclear complexes bridged
been developed extensively.1 These ensembles represent poten-
tial uses as precursors of electronic,2 photophysical materials,3
photonic devices,4 catalysts,5 sensors,6 and in basic host–
guest chemistry.7 By employing mononuclear units, such as
by oxalato or chloranilate and pyridyl-based subunits.12 These new
half-sandwich complexes with rectangle, prism or box shape are
expected to play an exciting role in host–guest chemistry as gas
storage materials.
M(diamine)22+, M(diphosphine)2 (M = Pd and Pt), connected
2+
Oxamide type compounds comprise a very interesting family
in coordination chemistry, as they can chelate as well as bridge
the metal ions to construct discrete and extended structures via
the cis or trans conformation.13 These coordination compounds
containing oxamidate derivatives have been studied extensively,
they may similarly be good magnetic mediators and useful for
magnetic materials and catalysis.14 However metal complexes with
the oxamidato ligand to build two-dimensional organometallic
rectangles have not been reported as far as we know, although
these supramolecular structures may display interesting functional
properties and applications in various fields.
Herein we report the stepwise formation of bi- and tetranuclear
half-sandwich ruthenium complexes bearing oxamidato bridges,
based on pyridyl subunits. A new series of bi- and tetranu-
clear ruthenium complexes was synthesized and characterized
(Scheme 1). The molecular structures of the binuclear complex [(p-
cymene)2Ru2(m-N,N ¢-diphenyloxamidato)Cl2] (1) and the tetranu-
clear complexes [(p-cymene)4Ru4(m-N,N ¢-diphenyloxamidato)2(m-
4,4¢-bpy)2] (4a), [(p-cymene)4Ru4(m-N,N ¢- diphenyloxamidato)2(m-
bpe)2] (5a) were confirmed by single crystal X-ray analyses.
by appropriate linkers such as 4,4¢-bipyridine, diverse structures of
supramolecules have been synthesized by many groups.8 Cotton
and co-workers have achieved supramolecular arrays based on
dimetal building units [M2(DAniF)], where M = Mo, Rh or
Ru and DAniF is an N,N ¢-di-p-anisylformamidinate anion.9 This
strategy results in neutral rather than highly positive oligomers
and networks, which can then be oxidized in a controlled way, with
retention of structural integrity. An enormous range of structures
are available by using different metals and organic ligands, which
could show special electrochemical activity, and other properties.
Hupp and Lu reported the preparation of rhenium rectangles
containing two different rigid or semi-rigid bifunctional ligands
which exhibited interesting electrochemistry and photophysical
properties.10
Multinuclear rectangles and cages based on Ru, Co, Ir, Rh
and Re have been studied extensively by many groups, as there
are three available coordination sites of (arene)-Ru, CpCo, Cp*M
(M = Rh, Ir) or Re(CO)3 complexes that can be used to construct
metallamacrocyclic complexes as well as coordination cages, some
Shanghai Key Laboratory of Molecular Catalysis and Innovative Material,
Department of Chemistry, Advanced Materials Laboratory, Fudan Univer-
sity, Shanghai, 200433, China. E-mail: gxjin@fudan.edu.cn; Fax: +86-21-
65641740; Tel: +86-21-65643776
† CCDC reference numbers 731558 (1), 731560 (4a), and 731559 (5a).
For crystallographic data in CIF or other electronic format see DOI:
10.1039/b909357e
Result and discussion
As shown in Scheme 1, when oxamide compounds were treated
successively with 2 equivs of n-BuLi in THF at -78 ◦C
and 1 equiv of [(p-cymene)RuCl2]2, the binuclear complexes
8426 | Dalton Trans., 2009, 8426–8431
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Scheme 1 Synthesis of bi- and tetranuclear complexes.
[(p-cymene)2Ru2(m-N,N ¢-bis(aryl)oxamidato)Cl2] (1, aryl = Ph; 2,
aryl = C6H4-p-Me; 3, aryl = C6H4-p-Cl) were formed in about 50%
yield. All the binuclear complexes are soluble in common organic
solvents such as CH2Cl2, CHCl3 and THF. The IR spectra showed
a strong absorption at approximately 1605 cm-1 for 1, 1589 cm-1
˚
are separated by 5.5567 A, which is closely similar to the Ru ◊ ◊ ◊ Ru
distance (5.50 A) of [(p-cymene)2Ru2(m-h -C2O4)Cl2].11a The Ru–N
and Ru–O bond distances are 2.101 and 2.083 A, respectively. The
Ru–Cl bond distance is 2.410 A. The two Cl atoms are oriented in
4
˚
˚
˚
a trans manner.
for 2 and 1598 cm-1 for 3 owing to the C O stretching of the
=
When the binuclear complexes were reacted with AgOTf in
CH3OH (scheme 1) for 4 h, then the AgCl removed by filtration
and the pyridinyl linker 4,4¢-bpy added, the tetranuclear rectangles
were formed after 15 h stirring. Tetranuclear complexes were
formulated as [(p-cymene)4Ru4(m-N,N ¢-bis(aryl)oxamidato)2(m-
4,4¢-bpy)2](OTf)4 (4a, aryl = Ph; 4b, aryl = C6H4-p-Me; 4c,
aryl = C6H4-p-Cl). The IR spectra showed a strong band at about
1605 cm-1 for 4a, 1588 cm-1 for 4b and 1598 cm-1 for 4c indicating
the presence of the coordinated bis-bidentate oxamidato ligands.
The 1H NMR spectra showed two double resonances at d = 8.23,
8.30 ppm due to dipyridyl protons of 4,4¢-bpy for 4a. Similarly,
the resonances of 4b at d = 7.98, 8.29 ppm and 4c at d = 7.04,
oxamidato ligands. The 1H NMR spectra showed signals at about
d = 7.1–7.5 ppm for the oxamidato ligands and d = 4.6–5.2 ppm
for the arene of the p-cymene, and the signals of N–H were absent.
The molecular structure of 1 was determined by X-ray diffrac-
tion methods. A perspective drawing of 1 with the atomic
numbering scheme is given in Fig. 1. The crystal structure of 1
consists of binuclear units, connected by a oxamidato ligand, and
each ruthenium atom is surrounded by one O atom and one N
atom from the oxamidato ligand and one Cl atom. All of the
ruthenium centers have six-coordinate geometry, assuming that
the p-cymene occupies three coordination sites. The two Ru atoms
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Fig.
1 Complex 1 with thermal ellipsoids drawn at the 30%
level. All hydrogen atoms are omitted for clarity. Selected dis-
◦
˚
tances (A) and angles ( ): Ru(1)–O(1) 2.091(6), Ru(1)–N(1) 2.098(9),
Ru(1)–Cl(1) 2.403(4), O(1)–C(1) 1.284(12), N(1)–C(1A) 1.283(13),
N(1)–C(2) 1.450(13), O(1)–Ru(1)–N(1) 77.2(3), N(1)–Ru(1)–Cl(1) 84.8(2),
O(1)–Ru(1)–Cl(1) 83.5(3), C(1A)–N(1)–Ru(1) 115.4(7), C(1)–O(1)–Ru(1)
114.1(6), C(2)–N(1)–Ru(1) 124.5(6).
8.24 ppm in the 1H NMR spectra demonstrate the coexistence of
4,4¢-bpy. 4a–c display similar signal patterns for the protons of the
p-cymene ligands.
Bpe-based molecular rectangles of general formula [(p-
Fig. 2 (a) Complex cation of 4a with thermal ellipsoids drawn at the
30% level. (b) Stacking of the molecules in crystals of 4a viewed along the
c-axis. Ru, N, O and C atoms are represented by green, red, blue and gray,
respectively. All hydrogen atoms, anions and solvent molecules are omitted
for clarity.
cymene)4Ru4(m-N,N ¢-bis(aryl)oxamidato)2(m-bpe)2](OTf)4
(5a,
aryl = Ph; 5b, aryl = C6H4-p-Me; 5c, aryl = C6H4-p-Cl) were
synthesized following a similar procedure using bpe instead of
4,4¢-bpy. The bands at about 1606 cm-1 for 5a, 1588 cm-1 for 5b
and 1598 cm-1 for 5c in the IR spectra can be assigned to the
11a
1
˚
=
cavity with the dimensions of 5.53 ¥ 11.32 A. These values are
C O stretching. The H NMR spectra of 5a showed resonances
very similar to the dimensions for 4a. The diagonal lengths in the
at approximately d = 7.63 (s), 7.78 (d), and 7.98 (d) ppm; the first
˚
=
structure are 12.40 and 14.55 A for 4a and 5a. The dihedral angle
is assigned to CH CH protons and the others are assigned to
1
=
between the two pyridine rings of the dipyridyl ligand for 4a is
13.1◦ (13.1◦), while for 5a it is 38.6◦ (16.6◦). As shown in Fig. 2b
and 3b, the molecules stack via the c-axis (4a) or a-axis (5a) to
form rectangular channels. Interestingly, while viewed along the
dipyridyl protons. Similarly, in the H NMR spectra, the CH CH
protons appear at 7.60 ppm for 5b and 5c as a singlet, respectively,
while the resonances for the pyridyl unit at approximately d = 7.96
(d), 7.75 (d) for 5b and 7.94 (d), 7.77 (d) ppm for 5c. 5a–c also
display similar signal patterns for the protons of the p-cymene
ligands.
=
c-axis, two 5a cations are arranged around the C C of bpe, thus
forming a ‘moonshaped’ structure. In addition, the counterions of
4a are located outside the channels, while the Et2O and two triflate
anions of 5a are located outside the channels and then another
two triflate anions are located inside the channels.
The structures of 4a and 5a have also been determined by
X-ray analyses. A perspective drawing of 4a and 5a with the
atomic numbering scheme are given in Fig. 2 and 3, respectively,
and selected bond lengths and angles are listed in Tables 1
and 2. The crystal units of 4a and 5a are composed of [(p-
cymene)2Ru4(m-N,N ¢-diphenyloxamidato)2(m-4,4¢-bpy)2]4+ or [(p-
cymene)2Ru4(m-N,N ¢-diphenyloxamidato)2(m-bpe)2]4+ cations and
OTf- counteranions in the solid. Assuming that the p-cymene
occupies three coordination sites, each Ru center adopts a
three-legged piano-stool conformation, which is a six-coordinate
geometry. Each Ru center is coordinated by one nitrogen atom
and oxygen atom from the oxamidato ligand and one nitrogen
atom of the 4,4¢-bpy or bpe ligand. The complex cations have a
rectangular cavity bridged by the oximadato ligand and 4,4¢-bpy
In conclusion, we have successfully synthesized a series of
bi- and tetranuclear p-cymene ruthenium complexes bearing
oxamidato ligands. Determined by single-crystal X-ray analysis,
the structure shows a rectangle in which two binuclear complexes
were connected by 4,4¢-bpy (4a) or bpe (5a) to construct a
rectangular cavity. We believe that it will be possible to synthe-
size supramolecules with prism or cubic frameworks following
this general strategy by using oxamidato complexes as starting
materials, this work is still in progress.
Experimental
˚
or bpe molecules with dimensions of 5.57 ¥ 11.28 A for 4a, and
˚
5.56 ¥ 13.65 A for 5a, respectively. The complex cation of [(p-
All manipulations were performed using standard Schlenk tech-
niques under an atmosphere of nitrogen. CH2Cl2 was dried over
cymene)2Ru4(m-h -C2O4)2(m-4,4¢-bpy)2]4+ is known to consist of a
4
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Table 1 Selected bond distances and angles for 4a
˚
Bond distances (A)
Ru(1)–O(1)
Ru(1)–N(3)
Ru(2)–N(4)
2.093(4)
2.115(5)
2.099(7)
Ru(1)–N(1)
Ru(2)–N(2)
Ru(2)–O(2)
2.115(5)
2.100(7)
2.152(7)
Bond angles (deg)
O(1)–Ru(1)–N(1)
N(1)–Ru(1)–N(3)
N(4)–Ru(2)–O(2)
C(1A) –N(1)–C(2)
C(2)–N(1)–Ru(1)
O(1)–C(1)–N(1A)
N(1A)–C(1)–C(1A)
77.45(19)
86.2(2)
80.9(3)
119.2(5)
126.5(4)
125.5(6)
114.5(7)
O(1)–Ru(1)–N(3)
N(4)–Ru(2)–N(2)
N(2)–Ru(2)–O(2)
C(1A) –N(1)–Ru(1)
C(1)–O(1)–Ru(1)
O(1)–C(1)–C(1A)
C(3)–C(2)–N(1)
85.07(18)
88.0(3)
78.3(3)
114.1(4)
113.6(4)
120.0(8)
117.8(8)
Table 2 Selected bond distances and angles for 5a
˚
Bond distances (A)
Ru(1)–O(1)
Ru(1)–N(3)
Ru(2)–N(2)
2.109(4)
2.124(6)
2.097(6)
Ru(1)–N(1)
Ru(2)–O(2)
Ru(2)–N(4)
2.116(5)
2.090(5)
2.140(6)
Bond angles (deg)
O(1)–Ru(1)–N(1)
N(1)–Ru(1)–N(3)
O(2)–Ru(2)–N(4)
C(2)–N(1)–Ru(1)
C(15)–N(3)–Ru(1)
C(1)–O(1)–Ru(1)
C(9)–N(2)–Ru(2)
C(2)–N(1)–C(3)
O(1)–C(1)–N(2)
N(2)–C(1)–C(2)
N(1)–C(2)–C(1)
77.53(19)
86.4(2)
84.4(2)
O(1)–Ru(1)–N(3)
O(2)–Ru(2)–N(2)
N(2)–Ru(2)–N(4)
C(3)–N(1)–Ru(1)
C(19)–N(3)–Ru(1)
C(1)–N(2)–Ru(2)
C(2)–O(2)–Ru(2)
C(1)–N(2)–C(9)
O(1)–C(1)–C(2)
N(1)–C(2)–O(2)
O(2)–C(2)–C(1)
82.4(2)
77.57(19)
85.3(2)
113.9(4)
122.2(5)
113.4(4)
125.7(4)
118.5(6)
127.8(6)
112.6(5)
115.0(5)
127.6(4)
120.6(5)
115.9(4)
113.9(4)
117.8(6)
119.6(6)
125.9(6)
118.8(6)
reagents were obtained from commercial sources and used without
further purification.
General procedure for preparation of binuclear complexes 1–3
2 equivs of n-BuLi (0.30 mL, 0.48 mmol) was added to a solution
of oxamide compound (0.2 mmol) in 15 mL THF at -78 ◦C. The
reaction mixture was allowed to warm to room temperature
gradually with stirring for about 2 h. Then the mixture was
added to a solution of equivalvent [(p-cymene)RuCl2]2 in 5 ml
THF, and stirred overnight. The solvent was evaporated in vacuo
and the residue was extracted with CH2Cl2 and the extract was
evaporated to dryness. Crystalline products were obtained from
CH2Cl2/hexane.
Fig. 3 (a) Complex cation of 5a with thermal ellipsoids drawn at the
30% level. (b) Stacking of the molecules in crystals of 5a viewed along the
a-axis. (c) the staggered disposition of 5a viewed along the c-axis. Ru, N,
O and C atoms are represented by green, blue, red, and gray, respectively.
All hydrogen atoms, anions and solvent molecules are omitted for clarity.
CaH2 and CH3OH was distilled over Mg/I2. THF, diethyl ether
and hexane were dried over Na and then distilled under nitrogen
immediately prior to use. The 1H NMR spectra were measured on
a VAVCE-DMX 400 spectrometer in CDCl3. Elemental analysis
was performed on an Elementar vario EL III analyzer. IR (KBr)
spectra were recorded on the Nicolet FT-IR spectrophotometer.
[(p-cymene)2Ru2(l-g4-oxa-R)Cl2] (R = Ph) (1). Red crystals,
yield: 100 mg, 64%. Anal. Calcd (%) for C34H38N2Cl2O2Ru2: C,
1
52.37; H, 4.88; N, 3.59. Found: C, 52.77; H,4.70; N, 3.43. H
NMR (400 MHz, CDCl3): d (ppm) 7.50 (d, 4H; CH, oxamidato),
7.18–7.34 (m, 6H; CH, oxamidato), 4.64–5.13 (m, 8H; CH,
p-cymene), 2.52 (m, 2H; CH(CH3)2), 1.95 (s, 6H; CH3), 1.13 (d, 6H;
CH(CH3)2), 1.09 (d, 6H; CH(CH3)2). IR (KBr): nCO = 1605 cm-1.
The oxamide compounds15 and [(p-cymene)RuCl2]2 were
16
prepared according to the reported procedures. Other chemical
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[(p-cymene)2Ru2(l-g4-oxa-R)Cl2] (R
=
C6H4-p-Me) (2).
20H; CH, oxamidato), 4.71–5.68 (m, 16H; CH, p-cymene), 2.52
(m, 4H; CH(CH3)2), 1.95 (s, 12H; CH3), 1.15 (d, 12H; CH(CH3)2),
0.97 (d, 12H; CH(CH3)2). IR (KBr): nCO = 1605 cm-1;
Red crystals, yield: 80 mg, 50%. Anal. Calcd (%) for
C36H42N2Cl2O2Ru2: C, 53.53; H, 5.20; N, 3.47. Found: C,
1
53.41; H, 5.42; N, 3.33. H NMR (400 MHz, CDCl3): d (ppm)
[(p-cymene)4(l-g4-oxa-R2)2Ru4(l-4,4¢-bpy)2] (OTf)4 (R = C6H4-
p-Me) (4b). Yield: 35.7 mg, 70%. Anal. Calcd (%) for
C96H100N8F12S4O16Ru4: C, 48.40; H, 4.20; N, 4.71. Found: C, 48.35;
H, 4.20; N, 4.57. 1H NMR (400 Hz, CDCl3): d = 8.29 (d, 8H; CH,
4,4¢-bpy), 7.98 (d, 8H; CH, 4,4¢-bpy), 7.54 (d, 8H; CH, oxamidato),
7.32 (d, 8H; CH, oxamidato), 5.15–5.58 (m, 16H; CH, p-cymene),
2.54 (m, 4H; CH(CH3)2), 2.50 (s, 12H; CH3, oxamidato), 1.64 (s,
12H; CH3, p-cymene), 1.17 (d, 12H; CH(CH3)2), 1.03 (d, 12H;
CH(CH3)2) ppm. IR (KBr): nCO = 1588 cm-1.
[(p-cymene)4Ru4(l-g4-oxa-R)2(l-4,4¢-bpy)2] (OTf)4 (R = C6H4-
p-Cl) (4c). Yield: 46 mg, 74%. Anal. Calcd (%) for
C92H88N8F12Cl4S4O16Ru4: C, 44.84; H, 3.57; N, 4.55. Found: C,
44.94; H, 3.60; N, 4.44. 1H NMR (400 Hz, CDCl3): d (ppm) 8.24
(d, 8H; CH, 4,4¢-bpy), 8.04 (d, 8H; CH, 4,4¢-bpy), 7.54–7.70 (m,
16H; CH, oxamidato), 5.03–5.80 (m, 16H; CH, p-cymene), 2.57
(m, 4H; CH(CH3)2), 1.99 (s, 12H; CH3), 1.17 (d, 12H; CH(CH3)2),
0.99 (d, 12H; CH(CH3)2). IR (KBr): nCO = 1598 cm-1.
7.39 (d, 4H; CH, oxamidato), 7.12 (d, 4H; CH, oxamidato),
4.62–5.13 (m, 8H; CH, p-cymene), 2.54 (m, 2H; CH(CH3)2),
2.37 (s, 6H; CH3, oxamidato), 1.99 (s, 6H; CH3, p-cymene), 1.13
(d, 6H; CH(CH3)2), 1.10 (d, 6H; CH(CH3)2) ppm. IR (KBr):
nCO = 1589 cm-1.
[(p-cymene)2Ru2(l-g4-oxa-R)Cl2] (R = C6H4-p-Cl) (3). Yel-
low crystals, yield: 87 mg, 51%. Anal. Calcd (%) for
C34H36N2Cl4O2Ru2: C, 48.11; H, 4.25; N, 3.30. Found: C, 47.96;
1
H, 4.55; N, 3.11. H NMR (400 MHz, CDCl3): d (ppm) 7.45
(d, 4H; CH, oxamidato), 7.31(d, 4H; CH, oxamidato), 4.65–5.18
(m, 8H; CH, p-cymene), 2.52 (m, 2H; CH(CH3)2), 1.99 (s, 6H;
CH3), 1.13 (d, 6H; CH(CH3)2), 1.10 (d, 6H; CH(CH3)2). IR (KBr):
nCO = 1598 cm-1.
General procedure for preparation of tetranuclear complexes 4a–5c
2 equivs AgOTf (36 mg, 0.14 mmol) was added to a solution of
binuclear complex (1, 2, or 3) (0.05 mmol) in CH3OH (15 mL)
at room temperature, and the mixture was stirred for 4 h,
followed by filtration. Equivalent 4,4¢-bpy (10 mg, 0.05 mmol)
or bpe (9 mg, 0.05 mmol) was added to the filtrate, and the
mixture was stirred for 15 h before being filtered. The solvent was
removed from the filtrate and the residue was recrystallized from
CH2Cl2/Et2O/hexane to give orange-red crystalline products.
[(p-cymene)4Ru4(l-g4-oxa-R)2(l-bpe)2] (OTf)4 (R = Ph) (5a).
Yield: 34 mg, 57%. Anal. Calcd (%) for C96H96N8F12S4O16Ru4:
C, 48.49; H, 4.04; N, 4.71. Found: C, 48.42; H, 4.02; N, 4.68. 1H
NMR (400 Hz, CDCl3): d (ppm) 7.98 (d, 8H; CH, bpe), 7.78 (d,
8H; CH, bpe), 7.39–7.69 (m, 20H; CH, oxamidato), 7.63 (s, 4H;
=
HC CH, bpe), 5.03–5.76 (d, 16H; CH, p-cymene), 2.50 (m, 4H;
CH(CH3)2), 2.10 (s, 12H; CH3), 1.08 (d, 12H; CH(CH3)2), 0.91 (d,
[(p-cymene)4Ru4(l-g4-oxa-R)2(l-4,4¢-bpy)2] (OTf)4 (R = Ph)
(4a). Yield: 35.3 mg, 59%. Anal. Calcd (%) for
C92H92N8F12S4O16Ru4: C, 47.50; H, 3.96; N, 4.82. Found: C,
47.66; H, 4.10; N, 4.68. 1H NMR (400 Hz, CDCl3): d (ppm) 8.30
(d, 8H; CH, 4,4¢-bpy), 8.03 (d, 8H; CH, 4,4¢-bpy), 7.76–7.38 (m,
12H; CH(CH3)2). IR (KBr): nCO = 1606 cm-1.
[(p-cymene)4Ru4(l-g4-oxa-R)2(l-bpe)2] (OTf)4 (R
p-Me) (5b). Yield: 31.5 mg, 52%. Anal. Calcd (%) for
=
C6H4-
C100H104N8F12S4O16Ru4: C, 49.34; H, 4.28; N, 4.60. Found: C,
Table 3 Crystallographic data and structure refinement parameters for 1, 4a and 5a
1·2CH2Cl2
4a·1.3CH2Cl2
5a·Et2O
Formula
Fw
cryst syst
C36H42Cl6N2O2Ru2
949.56
Triclinic
¯
P1
9.142(14)
9.416(14)
12.623(19)
103.083(19)
97.87(2)
106.425(18)
991(3)
C93.30H94.60Cl2.60F12N8O16Ru4S4
C100H106F12N8O17Ru4S4
2452.45
Orthorhombic
Pccn
16.560(5)
41.448(13)
15.582(5)
90
90
90
10695(6)
4
1.523
0.12 ¥ 0.10 ¥ 0.10
0.719
49321
11652
661
0.955
0.0747, 0.1841
0.1540, 0.2097
1.002/-0.580
2436.66
Monoclinic
C2/c
25.896(13)
20.555(10)
21.037(11)
90
101.970(8)
90
10954(9)
4
1.475
0.20 ¥ 0.18 ¥ 0.10
0.760
24569
10778
614
0.790
space group
˚
a (A)
˚
b (A)
˚
c (A)
a (deg)
b(deg)
g (deg)
3
˚
V (A )
Z
1
rcalcd (g/cm3)
cryst size (mm3)
m(Mo Ka)/mm-1
no. collected reflns
no. unique reflns
no. of params
GOF
1.591
0.12 ¥ 0.10 ¥ 0.08
1.200
4081
3401
220
1.178
0.1030, 0.2720
0.1189, 0.2921
2.845/-3.458
R1, wR2 [I > 2s(I)]a
R1, wR2 (all date)
max./min. residual density (e A )
0.0662, 0.1619
0.1455, 0.1834
1.240/-1.006
-3
˚
ꢀ
ꢀ
ꢀ
a R1 = ꢀFo| - |Fcꢀ (based on reflections with Fo > 2sF2)2. wR2 = [ [w(Fo - Fc2)2]/ [w(Fo2)2]]1/2; w = 1/[s (Fo2) + (0.095P)2]; P = [max(Fo
,
2
2
2
2
2
0) + 2Fc2]/3 (also with Fo > 2sF2).
8430 | Dalton Trans., 2009, 8426–8431
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1
49.35; H, 4.41; N, 4.42. H NMR (400 Hz, CDCl3): d = 7.96
(j) C. G. Oliveri, P. A. Ulmann, M. J. Wiester and C. A. Mirkin, Acc.
Chem. Res., 2008, 41, 1618.
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130, 839; (b) F. A. Cotton, C. Lin and C. A. Murillo, J. Am. Chem.
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1862; (b) S.-S. Sun, C. L. Stern, S. T. Nguyen and J. T. Hupp, J. Am.
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(d, 8H; CH, bpe), 7.75 (d, 8H; CH, bpe), 7.47-7.68 (m, 16H; CH,
oxamidato), 7.60 (s, 4H; HC CH, bpe), 5.06–5.69 (m, 16H; CH, p-
=
cymene), 2.51 (m, 4H; CH(CH3)2), 2.45 (s, 12H; CH3, oxamidato),
1.67 (s, 12H; CH3, p-cymene), 1.13 (d, 12H; CH(CH3)2), 0.95 (d,
12H; CH(CH3)2) ppm. IR (KBr): nCO = 1588 cm-1.
[(p-cymene)4Ru4(l-g4-oxa-R)2(l-bpe)2] (OTf)4 (R
=
C6H4-
p-Cl) (5c). Yield: 50 mg, 78%. Anal. Calcd (%) for
C96H92N8F12Cl4S4O16Ru4: C, 45.82; H, 3.66; N, 4.46. Found: C,
45.72; H, 3.70; N, 4.37. 1H NMR (400 Hz, CDCl3): d (ppm) 7.94
(d, 8H; CH, bpe), 7.77 (d, 8H; CH, bpe), 7.35–7.67 (m, 16H;
5 S. J. Lee, A.-G. Hu and W.-B. Lin, J. Am. Chem. Soc., 2002, 124, 12948.
6 M. Lahav, R. Gabai, A. N. Shipway and I. Willner, Chem. Commun.,
1999, 1937.
=
CH, oxamidato), 7.60 (s, 4H; HC CH, bpe), 5.10–5.82 (m, 16H;
7 K. Severin, Coord. Chem. Rev., 2003, 245, 3.
CH, p-cymene), 2.54 (m, 4H; CH(CH3)2), 1.98 (s, 12H; CH3, p-
cymene), 1.14 (d, 12H; CH(CH3)2), 0.94 (d, 12H; CH(CH3)2). IR
(KBr): nCO = 1598 cm-1.
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X-ray structure determination
Suitable crystals for X-ray analysis of 1, 4a, and 5a were
obtained by slow diffusion of diethyl ether/hexane into CH2Cl2
solutions of the corresponding compound. Data were collected
on a CCD-Bruker SMART APEX system at 293 K. All the
determinations of unit cell and intensity data were performed
with graphite-monochromated Mo Ka radiation (l = 0.71073
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Y.-H. Liu, T. Rajendran, S. Rajagopal and K.-L. Lu, Coord. Chem. Rev.,
2005, 249, 1085.
˚
A). All the data were collected at room temperature using
the w-scan technique. These structures were solved by direct
methods, using Fourier techniques, and refined on F2 by a full-
matrix least-squares method. All the calculations were carried
out with the SHELXTL-97 program.17 In complex 1 and 5a, all
of the non-hydrogen atoms were refined anisotropically, and all
hydrogen atoms were included in calculated positions. For 4a, all
of the non-hydrogen atoms were refined anisotropically except
C46 and C47, the SQUEEZE algorithm18 was used to omit the
disordered solvents. Crystal data, data collection parameters, and
the results of the analyses of compounds 1, 4a and 5a are listed in
Table 3.
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Dalton Trans., 2004, (10), 1656; (f) H. Piotrowski, K. Polborn, G. Hilt
and K. Severin, J. Am. Chem. Soc., 2001, 123, 2699; (g) Z. Grote, S.
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Acknowledgements
This work was supported by the National Science Foundation
of China (20531020, 20721063, 20771028), Shanghai Science and
Technology Committee (08DZ2270500, 08DJ1400103), Shanghai
Leading Academic Discipline Project (B108) and the National
Basic Research Program of China (2009CB825300).
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