Syntheses and properties of new metal-carbon bonded heteroleptic complexes of ruthenium(II) containing terpyridine coligand

Article abstract of DOI:10.1016/j.ica.2009.09.024

Reactions of 2-(arylazo)aniline, HL [H represents the dissociable protons upon orthometallation and HL is p-RC₆H₄N = NC₆H₄-NH₂; R = H for HL¹; CH₃ for HL² and Cl for HL³] with Ru(R₁-tpy)Cl₃ (where R₁-tpy is 4′-(R₁)-2,2′,6′′,2′′-terpyridine and R₁ = H or 4-N,N-dimethylaminophenyl or 4-methylphenyl) afford a group of complexes of type [Ru(L)(R₁-tpy)]·ClO₄ each of which contains C,N,N coordinated L^- as a tridentate ligand along with a terpyridine. Structure of one such complex has been determined by X-ray crystallography. All the Ru(II) complexes are diamagnetic, display characteristic ¹H NMR signals and intense dπ(Ru^II) → π*(tpy) MLCT transitions in the visible region. Cyclic voltammetric studies on [Ru(L)(R₁-tpy)]·ClO₄ complexes show Ru(II)-Ru(III) oxidation within 0.63-0.67 V versus SCE.

Full text of DOI:10.1016/j.ica.2009.09.024

Inorganica Chimica Acta 362 (2009) 5170–5174
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Inorganica Chimica Acta
journal homepage: www.elsevier.com/locate/ica
Syntheses and properties of new metal–carbon bonded heteroleptic complexes
of ruthenium(II) containing terpyridine coligand
Jahar Lal Pratihar a, Poulami Pattanayak a, Jui-Hsien Huang b, Surajit Chattopadhyay a,
*
a Department of Chemistry, University of Kalyani, Kalyani 741235, India
b Department of Chemistry, National Changhua University of Education, Changhua, Taiwan
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 28 July 2009
Received in revised form 4 September 2009
Accepted 8 September 2009
Available online 12 September 2009
Reactions of 2-(arylazo)aniline, HL [H represents the dissociable protons upon orthometallation and HL is
p-RC6H4N = NC6H4–NH2; R = H for HL1; CH3 for HL2 and Cl for HL3] with Ru(R1-tpy)Cl3 (where R1-tpy is
40-(R1)-2,20,600,200-terpyridine and R1 = H or 4-N,N-dimethylaminophenyl or 4-methylphenyl) afford a
group of complexes of type [Ru(L)(R1-tpy)]ꢀClO4 each of which contains C,N,N coordinated Lꢁ as a triden-
tate ligand along with a terpyridine. Structure of one such complex has been determined by X-ray crys-
tallography. All the Ru(II) complexes are diamagnetic, display characteristic 1H NMR signals and intense
*
Keywords:
d
p
(RuII) ?
p
(tpy) MLCT transitions in the visible region. Cyclic voltammetric studies on [Ru(L)(R1-tpy)]ꢀ-
2-(Arylazo)aniline
Terpyridine
Cycloruthenation
Redox
ClO4 complexes show Ru(II)–Ru(III) oxidation within 0.63–0.67 V versus SCE.
Ó 2009 Elsevier B.V. All rights reserved.
R
N
1. Introduction
N
N
The chemistry of Ru(II) complexes incorporating polypyridyl
ligands has expanded significantly in recent years. Particular
attention has been focused on the complexes of Ru(II) with
2,20,60,200-terpyridine (tpy) and 2,20-bypyridine (bpy) ligands
[1–9]. Homoleptic and heteroleptic tpy complexes have been pre-
pared using (tpy)RuCl3 precursors [1–6]. Often, reaction of triden-
tate ligands with (tpy)RuCl3, during the preparation of bis
heteroleptic complex of the type [Ru(L)(tpy)]n+, resulted in forma-
tion of intractable mixtures, and in particular when drastic reac-
tion condition was required [1–6]. Although there are abundant
reports on the synthesis of [Ru(L)(tpy)]n+ type of complexes where
L is tridentate but the reports are scarce where L binds to Ru centre
with Ru–C(aryl) bond [10–13]. Therefore, from our interest on the
design and synthesis of ligands, suitable for orthometallation, we
intended to prepare [Ru(L)(tpy)]n+ complexes where L is tridentate
with M–C(aryl) bond.
N
R1
N
NH2
R1-tpy
HL
2
1
R = H for HL1 (2a),
R1 = H for tpy,
4-methylphenyl
4-N,N-dimethylaminophenyl
CH3 for HL2 (2b),
Cl for HL3 (2c)
2. Results and discussion
2.1. Syntheses
Herein we report the synthesis of [Ru(L)(tpy)]+ complexes using
three kinds of substituted tpy ligands and three types of substi-
tuted HL as given in the structures 1 and 2. The complex forma-
tions have been authenticated on the basis of X-ray studies and
1H NMR spectroscopy. The redox property of the new Ru(II) cyclo-
metallates have been studied electrochemically.
description of redox orbitals have been ascribed on the basis of
single point DFT calculations.
Reaction of one equivalent 2-(arylazo)aniline (HL) 2 with Ru(R1-
tpy)Cl3, in refluxing methanol and subsequently upon treatment
with NaClO4, afforded [Ru(L)(R1-tpy)]ꢀClO4, 3. The composition of
diamagnetic [Ru(L)(R1-tpy)]ꢀClO4 complexes matched well with
the analytical data and total proton count in 1H NMR spectrum
(vide infra). Orthometallation of HL, substituting the ortho aryl
hydrogen of aryl ring, has been established from spectral
(1H NMR) data (see below) and confirmed by X-ray studies. Seven
complexes have been prepared varying the tpy moiety and HL as
given in Scheme 1.
A plausible
* Corresponding author. Tel.: +91 33 25828750; fax: +91 33 25828282.
E-mail address: scha8@rediffmail.com (S. Chattopadhyay).
0020-1693/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2009.09.024

J.L. Pratihar et al. / Inorganica Chimica Acta 362 (2009) 5170–5174
5171
R
R
N
N
Cl
N
(a)
N
N
N
Ru
Cl
R1
+
N
N
N
Ru
N
R1
(b)
Cl
NH2
NH2
ClO4
HL
[Ru(R1-tpy)Cl3]
[Ru(L)(R1-tpy)].ClO4
2
3
R
H
R1
3a
3b
3c
3d
3e
4-methylphenyl
4-methylphenyl
4-methylphenyl
CH3
Cl
H
4-N,N-dimethylaminophenyl
4-N,N-dimethylaminophenyl
Cl
H
H
CH3
Cl
3f
3g
Scheme 1. Synthesis of [Ru(L)(R1-tpy)]ꢀClO4, 3. (a) MeOH, (b) NaClO4.
2.2. Characterization
(ꢂ1455–1474 cmꢁ1) shifted to lower frequency upon complexa-
tion (1382–1409 cmꢁ1), consistent with coordination of the azo
nitrogen [14–22]. Ruthenium complexes exhibited a broad band
near 1090 cmꢁ1, characteristic of uncoordinated ClO4ꢁ. The IR data
are collected in Section 4.
The compositions of 3a–g matched well with the C, H, N analyt-
ical data and 1H NMR spectral data. The 1H NMR spectra (Supple-
mentary Figs. S15–S21) of the complexes were recorded in CDCl3.
The well resolved 1H NMR spectra of [Ru(L)(R1-tpy)]ꢀClO4, 3, com-
plexes are consistent with their structures. The significant features
that have been taken into consideration to elucidate the structures
are as follows: (i) The NH2 resonance of [Ru(L)(R1-tpy)]ꢀClO4, 3, ap-
peared as a singlet in the range of d 5.28–4.56 for two proton; (ii)
the total count of aromatic protons matched well with the total
number of protons (data are given in Section 4); (iii) a sharp singlet
appeared in the range of d 6.10–4.99 for the 3b, 3c and 3e–g
(where R = CH3 or Cl) indicating the orthometallation on the
substituted phenyl ring of HL.
All the complexes 3a–g, are soluble in common organic solvents
furnishing pink solutions. UV–Vis spectra of the complexes have
been recorded in dichloromethane solutions. All the complexes
displayed several absorptions in the visible and ultraviolet regions.
The absorptions near 500 nm has been assigned to the MLCT tran-
sition i.e. dp p (tpy) consistent with DFT results (see be-
(RuII) ?
*
low). An absorption near 1050 nm of lower intensity was
observed for all the complexes in contrast to the reported tpy com-
plexes of ruthenium [1–6]. A representative spectrum of 3a is
shown in Fig. 1. The UV–Vis spectral data are given in Section 4.
The IR spectra of the complexes (Figs. S8–S14 in the Supple-
mentary material) in solid KBr support mNH2 appeared as broad
band within the ranges 3261–3210 cmꢁ1. The mN@N of the ligands
2.3. X-ray structure
Suitable crystals of [Ru(L2)(4-methylphenyl-tpy)]ꢀClO4, 3b, were
grown by slow diffusion of dichloromethane solution into petro-
leum ether. A perspective view of the molecule has been shown
in Fig. 2 and selected bond distances and angles are collected in
Table 1. The monoanionic (L2)ꢁ ligand bind to the ruthenium metal
in C,N,N-tridentate fashion along with 40-(4-methyl phenyl)-
2,20,60,200-terpyridine (4-methylphenyl-tpy). Two tridentate ligands
are meridionally bound to the Ru(II) centre in the cationic complex
[Ru(L2)(4-methylphenyl-tpy)]+. The crystal consists of a cluster of
[Ru(L2)(4-methylphenyl-tpy)]+, [ClO4]ꢁ and dichloromethane sol-
vent in 3:3:2 stoichiometry in asymmetric unit. All the units of
[Ru(L2)(4-methylphenyl-tpy)]ꢀClO4 in the asymmetric unit are
equivalent having similar bond parameters. The RuN5C coordina-
tion sphere is distorted octahedral. The Ru1–N5 (central pyridine
nitrogen of terpyridine) distance [Ru1–N5, 1.967(5) Å] is shorter
than the terminal Ru1–N (pyridine) distances [Ru1–N4,
2.056(4) Å; Ru1–N6, 2.064(4) Å] like other ruthenium terpyridine
Fig. 1. UV–Vis spectrum of [Ru(L3)(4-methylphenyl-tpy)]ꢀClO4 in dichloromethane.

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J.L. Pratihar et al. / Inorganica Chimica Acta 362 (2009) 5170–5174
Fig. 2. Molecular structure of [Ru(L2)(4-methylphenyl-tpy)]+, (except ClO4) with
atom numbering scheme. The hydrogen atoms excepting on N(1) of the amino
groups have been omitted for clarity.
Fig. 3. Cyclic voltammogram of the [RuII(L3)(4-methylphenyl-tpy)]ꢀClO4 complex in
acetonitrile solution (0.1 M TBAP) at scan rate of 50 mV sꢁ1
.
Table 1
Selected bond distances (Å) and angles (°) for compound 3b.
2þ
½RuðLÞðR1-tpyÞꢃþ ꢁ e ! ½RuðLÞðR1-tpyÞꢃ
ð1Þ
Distances
Ru1–N1
Ru1–N2
Ru1–N4
Ru1–N5
Ru1–N6
N1–C1
N2–N3
N2–C6
N3–C7
2.218(5)
1.966(5)
2.056(4)
1.967(5)
2.064(4)
1.448(9)
1.298(7)
1.419(9)
1.386(10)
2.000(5)
According to the DFT results the composition of HOMO (Fig. 4a)
of [Ru(L)(R1-tpy)]+ is Ru centered indicating the oxidation to be
metal centered. The LUMO (Fig. 4b) is primarily concentrated on
the tpy ligand. Therefore the HOMO ? LUMO MLCT transition is
consistent with the assignment of UV–Vis spectra.
3. Concluding remarks
Ru1–C12
Quite a number of reports are there on Ru(II) terpyridine com-
plexes incorporating tridentate coligands. But the examples on the
corresponding organometallic analogues are limited. The new
organometallic heteroleptic bis complexes have been prepared uti-
lising the strategy of orthometallation. A series of such Ru(II) com-
plexes have been prepared containing tridentate C,N,N donor
ligands along with a terpyridine analogue. Therefore, we believe
that the methods of preparation and properties of orthometallated
Ru(II) complexes in presence of polypyridyl ligands may prove to
be useful in future.
Angles
N1–Ru1–N2
N1–Ru1–N4
N1–Ru1–N5
N1–Ru1–N6
N1–Ru1–C12
N2–Ru1–N4
N2–Ru1–N5
N2–Ru1–N6
N2–Ru1–C12
N4–Ru1–N5
N4–Ru1–N6
N4–Ru1–C12
N5–Ru1–N6
N5–Ru1–C12
79.8(2)
90.25(18)
105.14(18)
91.92(16)
158.1(2)
100.6(2)
175.02(18)
102.51(19)
78.3(2)
78.98(19)
156.9(2)
93.6(2)
78.21(18)
96.8(2)
4. Experimental
4.1. Materials
complexes [23–26]. The Ru1–C12 (2.000(5) Å), Ru1–N2(azo)
(1.966(5) Å) bond lengths of [Ru(L2)(4-methylphenyl-tpy)]+ are
within the normal range [27–29]. The [Ru1–N1(amine)
(2.218(5) Å) is longer than the other amine complexes [27–29]
due to the trans effect of aryl carbon [18]. In the crystal lattice
the perchlorate ions are held between two [Ru(L2)(p-methyl-
phenyl-tpy)]+ through hydrogen bond interaction with the amino
protons. The dichloromethane solvents are held in the crystal lat-
tice through non bonded interactions. The relevant packing dia-
gram has been given in Fig. S29 (Supplementary material).
The solvents used in the reactions were of reagent grade (E.
Marck, Kolkata, India) and were purified and dried by reported pro-
cedure [30]. Ruthenium trichloride was purchased from Johnson
Matthey, India. Ru(R1-tpy)Cl3 was synthesized following the
reported procedure [31]. The ligands 2-(phenylazo)aniline (HL1),
2-(4-methylphenylazo)aniline (HL2), and 2-(4-chloropheny-
lazo)aniline (HL3) were prepared following the reported proce-
dures [15–17].
4.2. Syntheses of complexes
2.4. Electrochemistry
4.2.1. [Ru(L)(R1-tpy)]ꢀClO4
The [Ru(L)(R1-tpy)ꢀClO4] complexes were obtained by following
a general procedure. Specific details are given below for a particu-
lar complex.
[Ru(L)(R1-tpy)]ꢀClO4 complexes exhibit one electron quasi
reversible oxidative cyclic voltammetric responses in the range of
0.63–0.67 V versus SCE in acetonitrile solution. A representative
cyclic voltammogram of 3c is shown in Fig. 3 and data are given
in Section 3. The oxidation has been assigned according to the cou-
ple of Eq. (1) where [Ru(L)(R1-tpy)]2+ is the Ru(III) analogue of
[Ru(L)(R1-tpy)]+.
4.2.1.1. [Ru(L1)(4-methylphenyl-tpy)]ꢀClO4 3a. HL1 (0.043 g,
0.22 mmol) was dissolved in methanol (40 mL) and to it were
added [Ru(4-methylphenyl-tpy)Cl3] (0.0 g, 0.22 mmol). The

J.L. Pratihar et al. / Inorganica Chimica Acta 362 (2009) 5170–5174
5173
Fig. 4. (a) HOMO of [Ru(L2)(4-methylphenyl-tpy)]+ and (b) LUMO of [Ru(L2)(4-methylphenyl-tpy)]+.
mixture was then refluxed for 4 h, when a pink solution was ob-
tained. Evaporation of these solutions afforded a dark solid
which was washed with petroleum ether several times to re-
move excess ligands, and then it was purified by thin layer
chromatography on silica plate with toluene/acetonitrile
(20:80) as the eluent. A pink band separated and the complex
was extracted from it with methanol and NaClO4. The pure crys-
tals, obtained upon evaporation of the solvent, was recrystal-
lised from dichloromethane-petroleum ether to afford
[Ru(L1)((4-methylphenyl-tpy)]ꢀClO4 as a crystalline dark solid.
Yield: 60%. Anal. Calc. for 3a: C, 56.70; H, 3.78; N, 11.67. Found:
3H); 6.98 (t, 2H); 6.90–6.84 (m, 3H); 6.64 (t, 1H); 4.64 (s, 2H);
3.10 (s, 6H). E1/2 [V]: 0.64.
4.2.1.5. [Ru(L3)(4-N,N-dimethylaminophenyl-tpy)]ꢀClO4 3e. Yield:
60%. Anal. Calc. for 3e: C, 53.63; H, 3.73; N, 12.51. Found: C,
53.69; H, 3.82; N, 12.43%. Electronic spectrum (kmax/nm (e/
dm2 molꢁ1), dichloromethane): 1060 (2300), 515 (8460), 365
(12820), 315 (18820), 290 (16820). IR (KBr pellets, cmꢁ1): mNH2
3244, 3212, mN@N 1381, mCl–O 1087. 1H NMR (CDCl3 + 1 drop
DMSO-d6, ppm): d 8.67 (d, 1H); 8.46 (s, 2H); 8.26 (d, 2H); 8.03
(d, 1H); 7.83 (d, 1H); 7.73–7.68 (m, 2H); 7.56–7.47 (m, 3H);
7.45–7.37 (m, 3H); 6.99–6.96 (m, 2H); 6.83–6.78 (m, 2H); 6.08 (s,
1H); 5.79–5.74 (m, 1H); 4.73 (s, 2H); 3.07 (s, 6H). E1/2 [V]: 0.65.
C, 56.64; H, 3.87; N, 11.74%. Electronic spectrum (kmax/nm (e/
dm2 molꢁ1), dichloromethane): 1040 (3200), 495 (6300), 365
(8125), 310 (17100), 290 (18300). IR (KBr pellets, cmꢁ1): mNH2
3260, 3234, mN@N 1404, mCl–O 1089. 1H NMR (CDCl3 + 1 drop
DMSO-d6, ppm): d 8.75 (d, 1H); 8.74 (s, 2H); 8.27 (d, 2H); 8.16
(d, 1H); 7.81 (d, 2H); 7.70 (t, 2H); 7.60–7.57 (m, 1H); 7.52 (d,
1H); 7.49–7.43 (m, 3H); 7.41 (d, 2H); 7.01 (t, 2H); 6.91–6.87
(m, 1H); 6.65–6.62 (m, 1H); 6.15 (d, 1H); 4.62 (s, 2H); 2.84 (s,
3H). E1/2 [V]: 0.63.
4.2.1.6. [Ru(L2)(tpy)]ꢀClO4 3f. Yield: 60%. Anal. Calc. for 3f: C, 52.22;
H, 3.60; N, 13.05. Found: C, 52.16; H, 3.67; N, 12.98%. Electronic
spectrum (kmax/nm
(e
/dm2 molꢁ1), dichloromethane): 1035
(1400), 525 (10430), 370 (17230), 315 (24860), 275 (27820), 235
(28850). IR (KBr pellets, cmꢁ1): mNH2 3261, 3242, mN@N 1383, mCl–O
1087. 1H NMR (CDCl3 + 1 drop DMSO-d6, ppm): d 8.67 (d, 1H);
8.34 (d, 2H); 8.19 (d, 2H); 8.01 (t, 2H); 7.69 (t, 2H); 7.57–7.49
(m, 3H); 7.47–7.41 (m, 2H); 6.99 (t, 2H); 5.81 (d, 1H); 5.45 (s,
1H); 5.28 (s, 2H); 1.90 (s, 3H). E1/2 [V]: 0.63.
4.2.1.2. [Ru(L2)(4-methylphenyl-tpy)]ꢀClO4 3b. Yield: 60%. Anal. Calc.
for 3b: C, 57.26; H, 3.98; N, 11.45. Found: C, 57.34; H, 4.02; N,
11.58%. Electronic spectrum (kmax/nm (e
/dm2 molꢁ1), dichloro-
methane): 1090 (5350), 500 (9800), 360 (14450), 310 (25560),
285 (27840). IR (KBr pellets, cmꢁ1): mNH2 3258, 3238, mN@N 1405,
mCl–O 1089. 1H NMR (CDCl3 + 1 drop DMSO-d6, ppm): d 8.70 (d,
1H); 8.49 (s, 2H); 8.27 (d, 2H); 8.04 (d, 1H); 7.85–7.81 (m, 2H);
7.73–7.68 (m, 2H); 7.55–7.34 (m, 7H); 7.00 (t, 2H); 6.68 (d, 1H);
5.89 (s, 1H); 4.56 (s, 2H); 2.47 (s, 3H); 1.91 (s, 3H). E1/2 [V]: 0.66.
4.2.1.7. [Ru(L3)(tpy)]ꢀClO4 3g. Yield: 60%. Anal. Calc. for 3g: C, 48.80;
H, 3.03; N, 12.65. Found: C, 48.65; H, 3.09; N, 12.74%. Electronic
spectrum (kmax/nm
(e
/dm2 molꢁ1), dichloromethane): 1040
(1020), 525 (6800), 365 (11650), 320 (18250), 275 (19450), 235
(19850). IR (KBr pellets, cmꢁ1): mNH2 3255, 3244, mN@N 1382,
mCl–O 1088. 1H NMR (CDCl3 + 1 drop DMSO-d6, ppm): d 8.69 (d,
1H); 8.35 (d, 2H); 8.20 (d, 2H); 8.10–8.00 (m, 2H); 7.76–7.67 (m,
2H); 7.58–7.51 (m, 2H); 7.49–7.44 (m, 2H); 7.05–6.99 (m, 2H);
6.85–6.81 (m, 1H); 6.01 (d, 1H); 4.99 (s, 1H); 4.66 (s, 2H). E1/2
[V]: 0.64.
4.2.1.3. [Ru(L3)(4-methylphenyl-tpy)]ꢀClO4 3c. Yield: 60%. Anal. Calc.
for 3c: C, 54.11; H, 3.47; N, 11.14. Found: C, 54.21; H, 3.42; N,
11.23%. Electronic spectrum (kmax/nm (e
/dm2 molꢁ1), dichloro-
methane): 1040 (2000), 500 (5920), 365 (9150), 310 (16780), 285
(17840). IR (KBr pellets, cmꢁ1): mNH2 3244, 3210, mN@N 1382, mCl–O
1087. 1H NMR (CDCl3 + 1 drop DMSO-d6, ppm): d 8.70 (d, 1H);
8.49 (s, 2H); 8.27 (d, 2H); 8.07 (d, 1H); 7.82 (d, 2H); 7.78–7.72
(m, 2H); 7.57–7.40 (m, 7H); 7.02 (t, 2H); 6.87 (d, 1H); 6.10 (s,
1H); 4.66 (s, 2H); 2.49 (s, 3H). E1/2 [V]: 0.67.
4.3. Physical measurements
Microanalysis (C, H, N) was performed using a Perkin–Elmer
240C elemental analyzer. Infrared spectra were recorded on a Per-
kin–Elmer L120-00A FT-IR spectrometer with the samples pre-
pared as KBr pellets. Electronic spectra were recorded on a
Shimadzu UV-1601 PC spectrophotometer. 1H NMR spectra were
obtained on Brucker DPX 400 and Brucker 500 RPX NMR spectrom-
eters in CDCl3 with 1 drop DMSO-d6 using TMS as the internal
standard. Electrochemical measurements were made under dini-
trogen atmosphere using a PAR model VARSASTAT-II potentiostat.
A platinum disc working electrode, a platinum wire auxiliary elec-
trode and an aqueous saturated calomel reference electrode (SCE)
were used in a three-electrode configuration. All electrochemical
4.2.1.4. [Ru(L1)(4-N,N-dimethylaminophenyl-tpy)]ꢀClO4 3d. Yield:
60%. Anal. Calc. for 3d: C, 56.11; H, 4.03; N, 13.09. Found: C,
56.23; H, 4.12; N, 13.11%. Electronic spectrum (kmax/nm (e/
dm2 molꢁ1), dichloromethane): 1070 (4550), 517 (20000), 365
(27560), 315 (42440), 290 (38300). IR (KBr pellets, cmꢁ1): mNH2
3247, 3215, mN@N 1406, mCl–O 1085. 1H NMR (CDCl3 + 1 drop
DMSO-d6, ppm): d 8.73 (d, 1H); 8.46 (s, 2H); 8.23 (d, 2H); 8.15
(d, 1H); 7.82 (d, 2H); 7.69 (t, 2H); 7.57–7.51 (m, 3H); 7.45 (d,

5174
J.L. Pratihar et al. / Inorganica Chimica Acta 362 (2009) 5170–5174
Table 2
Crystallographic data for 3b.
can be obtained free of charge from The Cambridge Crystallo-
graphic 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 doi:10.1016/j.ica.2009.09.024.
Chemical formula
Formula weight
Crystal system
Space group
a (Å)
3(C34H27N6Ru), 3(ClO4), 2(CH2Cl2)
2330.26
Triclinic
ꢀ
P1
16.681(2)
18.454(5)
18.852(4)
76.589(12)
63.794(8)
86.571(12)
0.71073
5058.7(19)
2364
2
293
1.530
0.698
References
b (Å)
c (Å)
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a
(°)
b (°)
(°)
c
k (Å)
V (Å3)
F(0 0 0)
Z
T (K)
D (mg/mꢁ3)
l
(mmꢁ1
)
R1 (all data)
wR2 [I > 2 (I)]
Goodness-of-fit (GOF)
0.0602
0.1618
1.02
r
data were collected at 298 K and are uncorrected for junction
potentials.
4.4. DFT calculations
Using the X-ray coordinates of the [Ru(L2)(4-methylphenyl-
tpy)]ꢀClO4 complex, ground state electronic structure calculations
have been carried out using DFT [32] methods with the GAUSSIAN
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Parr (LYP) correlation function [34] was used throughout the study.
LANL2DZ valence and effective core potential functions were used.
All energy calculations were performed using the self-consistent
field ‘‘tight” option of the GAUSSIAN 03 program to ensure sufficiently
well converged values for the state energies.
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4.5. Crystallography
Singlecrystals of [Ru(L2)(4-methylphenyl-tpy)]ꢀClO4 were grown
by slow diffusion of a dichloromethane solution into petroleum
ether at 298 K. Data were collected by
Smart CCD diffractometer with Mo K
graphite crystal. Structure solution was done by direct method with
SHELXS-97 program [35]. Full matrix least square refinements on F2
were performed using SHELXL-97 program [36]. All non-hydrogen
atoms were refined anisotropically using reflections I > 2r(I). All
hydrogens were included at calculated positions. The data collection
parameters and relevant crystal data are collected in Table 2.
x
-scan technique on a Bruker
a
radiation monochromated by
(b) M.J. Frisch, G.W. Trucks, H.B. Schlegel, G.E. Scuseria, M.A. Robb, J.R.
Cheeseman Jr., J.A. Montgomery, T. Vreven, K.N. Kudin, J.C. Burant, J.M.
Millam, S.S. Iyengar, J. Tomasi, V. Barone, B. Mennucci, M. Cossi, G. Scalmani,
N. Rega, G.A. Petersson, H. Nakatsuji, M. Hada, M. Ehara, K. Toyota, R.
Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, M.
Klene, X. Li, J.E. Knox, H.P. Hratchian, J.B. Cross, R. ammi, C. Pomelli, J.W.
Ochterski, P.Y. Ayala, K. Morokuma, G.A. Voth, P. Salvador, J.J. Dannenberg,
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A.D. Rabuck, K. Raghavachari, J.B. Foresman, J.V. Ortiz, Q. Cui, A.G. Baboul, S.
Clifford, J. Cioslowski, B.B. Stefanov, G. Liu, A. Liashenko, P. Piskorz, I.
Komaromi, R.L. Martin, D.J. Fox, T. Keith, A. Al-Laham, C.Y. Peng, A.
Nanayakkara, M. Challacombe, P.M.W. Gill, B. Johnson, W. Chen, M.W.
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Wallingford, CT, 2004.
Acknowledgements
We are thankful to the DST (New Delhi) for funding under DST-
SERC (SR/S1/IC-0026/2007) project. JP is thankful to the CSIR (New
Delhi) for his fellowship (No. 09/106(0097)2K8-EMR-I). We are
thankful to Dr. G. Saha (Chembiotek). The necessary laboratory
and infrastructural facility are provided by the Department of
Chemistry, University of Kalyani. The support of DST under FIST
and UGC SAP program to the Department of Chemistry, University
of Kalyani is acknowledged.
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[35] G.M. Sheldrick, SHELXS-97, University of Göttingen, Göttingen, Germany,
1990.
Appendix A. Supplementary material
[36] G.M. Sheldrick, SHELXL-97, Program for the Refinement of Crystals
Structures from Diffraction Data, University of Göttingen, Göttingen,
Germany, 1997.
CCDC 740067 [(L2)Ru(4-methylphenyl-tpy)]ꢀClO4, 3b contains
the supplementary crystallographic data for this paper. These data