Syntheses and structures of blue-luminescent mercury(11) complexes with 2,6-bis(imino)pyridyl ligands

Article abstract of DOI:10.1021/ic900339u

Seven five-coordinate 2,6-bis(imino)pyridyl mercury complexes, [2,6-(ArN=CMe)₂C₅H₃NHgCI₂· nCH3CN] (Ar = C₆H₅, n = 1.5,1; Ar = 2,6- ⁱPr₂C₆H₃, n =

Full text of DOI:10.1021/ic900339u

6034 Inorg. Chem. 2009, 48, 6034–6043
DOI: 10.1021/ic900339u
Syntheses and Structures of Blue-Luminescent Mercury(II) Complexes with
2,6-Bis(imino)pyridyl Ligands
Ruiqing Fan,*,† Yulin Yang,*,† Yanbin Yin,† WuLiJi Hasi,† and Ying Mu‡
†Department of Chemistry, Harbin Institute of Technology, Harbin 150001, P. R. of China, and
‡Key Laboratory for Supramolecular Structure and Materials of Ministry of Education, School of Chemistry,
Jilin University, Changchun 130012, P. R. of China
Received February 20, 2009
Seven five-coordinate 2,6-bis(imino)pyridyl mercury complexes, [2,6-(ArNdCMe)2C5H3NHgCl2 nCH3CN] (Ar = C6H5,
3
n = 1.5, 1; Ar = 2,6-iPr2C6H3, n = 0, 2; Ar = 2,6-Me2C6H3, n = 1, 3; Ar = 2-MeC6H4, n = 1, 4; Ar = 4-MeC6H4, n = 1, 5; Ar =
2,4,6-Me3C6H2, n = 1, 6; Ar = 2,6-Et2C6H3, n = 0, 7), were synthesized by reactions of the corresponding bis(imino)pyridine
ligands with HgCl2 in CH3CN, and in good yield. The structures of complexes 1-6 were determined by single-crystal X-ray
diffraction. In all complexes, the metal center is tridentately chelated by the ligand and further coordinated by two chlorine
atoms, resulting in a distorted trigonal bipyramidal geometry. All complexes have blue luminescence at room temperature
in solution and the solid state. At 293 K in a CH2Cl2 solution, the fluorescent emission maxima for complexes 1-7 are at λ =
395, 400, 407, 403, 427, 415, and 403 nm, respectively, which can be attributed to ligand-centered π* f π transitions.
Introduction
their good performance in sensor technologies and electrolu-
minescent devices.1-11 For example, luminescent noble
Luminescent coordination compounds with nitrogen-con-
taining ligands have attracted much attention recently due to
(5) (a) Yam, V. W. W.; Pui, Y. L.; Cheug, K. K. J. Chem. Soc., Dalton
Trans. 2000, 3658. (b) Kunkely, H.; Vogler, A. J. Photochem. Photobiol., A
2001, 144, 69. (c) Das, S.; Hung, C.-H.; Goswami, S. Inorg. Chem. 2003, 42,
8592. (d) Atoub, N.; Mahmoudi, G.; Morsali, A. Inorg. Chem. Commun.
2007, 10, 166.
(6) (a) Niu, C.-Y.; Wu, B.-L.; Zheng, X.-F.; Zhang, H.-Y.; Hou, H.-W.
Cryst. Growth Des. 2008, 8, 1566. (b) Chu, Z.-L; Zhu, H.-B.; Hu, D.-H.;
Huang, W.; Gou, S.-H. Cryst. Growth Des. 2008, 8, 1599. (c) Ranjbar, Z. R.;
Morsali, A. Inorg. Chim. Acta 2007, 360, 2056.
(7) (a) Tang, C. W.; VanSlyke, S. A. Appl. Phys. Lett. 1987, 51, 913. (b)
Baldo, M. A.; Lamansky, S.; Burrows, P. E.; Thompson, M. E.; Forrest, S.
R. Appl. Phys. Lett. 1999, 75, 4. (c) Adachi, C.; Kwong, R. C.; Djurovich, P.;
Adamovich, V.; Baldo, M. A.; Thompson, M. E.; Forrest, S. R. Appl. Phys.
Lett. 2001, 79, 2082.
(8) (a) Sprouse, S.; King, K. A.; Spellane, P. J.; Watts, R. J. J. Am. Chem.
Soc. 1984, 106, 6647. (b) Balzani, V.; Juris, A.; Venturi, M.; Campagna, S.;
Serroni, S. Chem. Rev. 1996, 96, 759. (c) Tian, A.-X.; Ying, J.; Peng, J.; Sha,
J.-Q.; Pang, H.-J.; Zhang, P.-P.; Chen, Y.; Zhu, M.; Su, Z.-M. Inorg. Chem.
2009, 48, 100.
*To whom correspondence should be addressed. Fax: +86-451-86418270.
E-mail: fanruiqing@163.com (R.F.), and ylyang@hit.edu.cn (Y.Y.).
(1) (a) Yu, G.; Yin, S. W.; Liu, Y. Q.; Shuai, Z. G.; Zhu, D. B. J. Am.
Chem. Soc. 2003, 125, 14816. (b) Berry, S. M.; Bebout, D. C. Inorg. Chem.
2005, 44, 27. (c) Aragoni, M. C.; Arca, M.; Demartin, F.; Devillanova, F. A.;
Lsaia, F.; Garau, A.; Lippolis, V.; Jalali, F.; Papke, U.; Shamsipur, M.; Tei,
L.; Yari, A.; Verani, G. Inorg. Chem. 2002, 41, 6623. (d) Xu, X. X.; Lu, Y.;
Wang, E. B.; Ma, Y.; Bai, X. L. Cryst. Growth Des. 2006, 6, 2029. (e) Xu, X.
X.; Lu, Y.; Wang, E. B.; Ma, Y.; Bai, X. L. Inorg. Chim. Acta 2007, 360, 455.
(f) Liu, Q. D.; Wang, R. Y.; Wang, S. N. J. Chem. Soc., Dalton Trans. 2004,
2073.
(2) (a) Li, X. P.; Zhang, J. Y.; Liu, Y.; Pan, M.; Zheng, S. R.; Kang, B. S.;
Su, C. Y. Inorg. Chim. Acta 2007, 360, 2990. (b) Jin, F.; Zhou, H.-P.; Wang,
X.-C.; Hu, Z.-J.; Wu, J.-Y.; Tian, Y.-P.; Jiang, M.-H. Polyhedron 2007, 26,
1338. (c) Bazzicalupi, C.; Bencini, A.; Berni, E.; Bianchi, A.; Borsari, L.;
Giorgi, C.; Valtancoli, B.; Lodeiro, C.; Lima, J. C.; Parola, A. J.; Pina, F. J.
Chem. Soc., Dalton Trans. 2004, 591. (d) Shao, K.-Z.; Zhao, Y.-H.; Wang,
X.-L.; Lan, Y.-Q.; Wang, D.-J.; Su, Z.-M.; Wang, R.-S. Inorg. Chem. 2009,
48, 10.
(3) (a) Wu, Q.; Lavigne, J. A.; Tao, Y.; D’Iorio, M.; Wang, S. Inorg.
Chem. 2000, 39, 5248. (b) Yam, V. W. W.; Pui, Y. L.; Wong, K. M. C.;
Cheung, K. K. J. Chem. Soc. Chem. Commun. 2000, 1751. (c) Yang, W.;
Schmider, H.; Wu, Q.; Zhang, Y. S.; Wang, S. Inorg. Chem. 2000, 39, 2397.
(d) Wong, W. Y.; Tsang, K. Y.; Tam, K. H.; Lu, G. L.; Sun, C. J. Organomet.
Chem. 2000, 601, 237. (e) Sazanovich, L. V.; Kirmaier, C.; Hindin, E.; Yu, L.;
Bocian, D. F.; Lindsey, J. S.; Holten, D. J. Am. Chem. Soc. 2004, 126, 2664.
(f) Chen, X.-L.; Gou, L.; Hu, H.-M.; Fu, F.; Han, Z.-X.; Shu, H.-M; Yang,
M.-L.; Xue, G.-L.; Du, C.-Q. Eur. J. Inorg. Chem. 2008, 239.
(9) (a) Jia, W. L.; Liu, Q. D.; Wang, R.; Wang, S. Organometallics 2003,
22, 4070. (b) Lamansky, S.; Djurovich, P.; Murphy, D.; Abdel-Razzag, F.;
Lee, H. E.; Adachi, C.; Burrows, P. E.; Forrest, S. R.; Thompson, M. E. J.
Am. Chem. Soc. 2001, 123, 4304.
(10) (a) Xia, H.; Zhang, C.; Liu, X.; Qiu, S.; Lu, P.; Shen, F.; Zhang, J.;
Ma, Y. J. Phys. Chem. B 2004, 108, 3185. (b) Tung, Y. L.; Wu, P. C.; Liu, C.
S.; Chi, Y.; Yu, J. K.; Hu, Y. H.; Chou, P. T.; Peng, S. M.; Lee, G. H.; Tao,
Y.; Arthur, J. C.; Shu, C. F.; Wu, F. I. Organometallics 2004, 23, 3745. (c)
Zhang, P.; Guo, J. H.; Wang, Y.; Pang, W. Q. Mater. Lett. 2002, 53, 400. (d)
Tung, Y. L.; Lee, S. W.; Chi, Y.; Chen, L. S.; Shu, C. F.; Wu, F. I.; Carty, A.
J.; Chou, P. T.; Peng, S. M.; Lee, G. H. Adv. Mater. 2005, 17, 1059.
(11) (a) Chen, Y. L.; Lee, S. W.; Chi, Y.; Hwang, K. C.; Kumar, S. B.; Hu,
Y. H.; Cheng, Y. M.; Chou, P. T.; Peng, S. M; Lee, G. H.; Yeh, S. J.; Chen, C.
T. Inorg. Chem. 2005, 44, 4287. (b) Carlson, B.; Phelan, G. D.; Kaminsky,
W.; Dalton, L.; Jiang, X. Z.; Liu, S.; Jen, A. K.-Y. J. Am. Chem. Soc. 2002,
124, 14162. (c) Xia, H.; Zhang, C.; Qiu, S.; Lu, P.; Zhang, J.; Ma, Y. Appl.
Phys. Lett. 2004, 84, 290.
(4) (a) Anjali, K. S.; Pui, Y. L.; Yam, V. W. W.; Vittal, J. J. Inorg. Chim.
::
Acta 2001, 319, 57. (b) Zhu, H.; Strobele, M.; Yu, Z.; Wang, Z.; Meyer, H. J.;
You, X. Inorg. Chem. Commun. 2001, 4, 577. (c) Kang, Y.; Seward, C.; Song,
D.; Wang, S. Inorg. Chem. 2003, 42, 2789. (d) Yam, V. W. W.; Pui, Y. L.;
Cheung, K. K. New J. Chem. 1999, 23, 1163. (e) Du, M.; Li, C. P.; Zhao, X.
J.; Yu, Q. CrystEngComm 2007, 9, 1011.
r
2009 American Chemical Society
pubs.acs.org/IC
Published on Web 06/03/2009

Article
Inorganic Chemistry, Vol. 48, No. 13, 2009 6035
Table 1. Crystal Data and Structure Refinement for 1-6
data
1
2
3
4
5
6
formula
fw
C24H23.5N4.5Cl2Hg C33H43N3Cl2Hg C27H30N4Cl2Hg C25H26N4Cl2Hg C25H26N4Cl2Hg C29H34N4Cl2Hg
710.09
646.47
triclinic
P1
753.19
triclinic
P1
682.04
monoclinic
P21/c
653.99
triclinic
P1
653.99
monoclinic
C2/c
cryst syst
space group
monoclinic
P21/n
˚
a/A
8.9830(18)
12.591(3)
22.783(5)
92.14(3)
97.30(3)
93.55(3)
2548.4(9)
2a
8.8470(18)
9.853(2)
21.037(4)
80.47(3)
88.41(3)
66.89(3)
1662.0(6)
2
13.377(3)
14.863(3)
14.499(3)
9.3470(19)
12.994(3)
21.585(4)
93.59(3)
90.64(3)
98.18(3)
2589.3(9)
2a
21.8046(14)
14.8059(10)
16.8208(12)
16.826(5)
14.980(4)
23.598(6)
˚
b/A
˚
c/A
R/deg
β/deg
γ/deg
108.44(3)
101.4770(10)
92.896(4)
3
˚
volume (A )
Z
2735.0(10)
4
1.656
5.845
1336
5321.8(6)
4
0.816
3.002
1272
5941(3)
4a
1.588
Dcalcd, g cm-3
μ, mm-1
F(000)
1.685
6.268
1252
1.505
4.816
752
1.678
6.170
1272
5.385
2800
θ range for data collection
limiting indices
1.89-27.48°
-11 e h e 11
-15 e k e 16
-29 e l e 29
2.28-27.48°
0 e h e 11
-11 e k e 12
-27 e l e 27
1.81-27.48°
-17 e h e 17
-19e k e 19
-18 e l e 18
0.95-27.48°
-11 e h e 11
-16 e k e 16
-28 e l e 27
1.67-28.59°
-22 e h e 28
-19e k e 19
-19 e l e 21
1.61-26.14°
-20 e h e 20
-18e k e 14
-28e l e 28
absorption correction
data/restraints/params
goodness-of-fit on F2
final R indices [I > 2σ(I)]
semiempirical
10288/12/548
1.026
7359/12 /362
1.014
6041/6/315
1.044
9842/28/572
0.967
6259/6/290
0.852
11585/12/651
0.667
b
R1
wR2
0.0589
0.1329
0.0561
0.1461
0.0579
0.1479
0.0640
0.1167
0.0398
0.0753
0.0488
0.0884
c
R indices (all data)
R1
wR2
largest diff. peak/hole (e A
b
0.0982
0.1511
2.399/-1.193
0.0821
0.1529
1.948/-1.596
0.0732
0.1625
2.150/-1.791
0.1460
0.1432
1.174/-0.769
0.0718
0.0837
1.606/-0.599
0.1066
0.1094
1.336/-1.434
c
-3
˚
)
3
P
P
P
P
2
a There are two crystallographically independent molecules in the asymmetric unit. b R1=
Fo| - |Fc
/
|Fo|. c wR2=[ [w (Fo - Fc2)2]/ [ w
(Fo2)2]]1/2
.
Scheme 1
metal complexes with bipyridine-containing ligands have at-
tracted much attention because of their high luminescent
efficiency.10,11 However, the lower synthetic yields and higher
costs of these complexes are disadvantages for their use as
optoelectronic materials. Lower-cost d10 metal complexes with
nitrogen-containing ligands have been synthesized and their
luminescent behavior studied,1-6 among which, a few mercury
complexes have been reported in studies concerning their
luminescence behavior.2,5 It has been found that, for a given
complex, the size of the π-conjugated system of the ligand and
the electronic effect of substituents on the ligand are important
factors for modulating its luminescent properties.3e,4c,4d On the
other hand, the design and synthesis of efficient luminescent
chelating Hg(II) complexes is also of importance for detection
of Hg(II), as mercury and its derivatives are highly toxic
contaminants of the environment.12 In the past several years,
iron and cobalt complexes with bulky aryl-substituted
(12) (a) Guo, X. F.; Qian, X. H.; Jia, L. H. J. Am. Chem. Soc. 2004, 126,
2272. (b) Yu, Y.; Lin, L.-R.; Yang, K.-B.; Zhong, X.; Huang, R.-B.; Zheng,
L.-S. Talanta 2006, 69, 103. (c) Wang, L.; Zhu, X.- J.; Wong, W.-Y.; Guo, J.-
P.; Wong, W.-K.; Li, Z.-Y. J. Chem. Soc., Dalton Trans. 2005, 3235.
(13) (a) Fan, R. Q.; Zhu, D. S.; Mu, Y.; Li, G. H.; Yang, Y. L.; Su, Q.;
Feng, S. H. Eur. J. Inorg. Chem. 2004, 4891. (b) Fan, R. Q.; Zhu, D. S.; Mu,
Y.; Su, Q.; Xia, H. Synth. Met. 2005, 149, 135. (c) Fan, R. Q.; Zhu, D. S.; Mu,
Y; Li, G. H.; Su, Q.; Ni, J. G.; Feng, S. H. Chem. Res. Chin. Univ. 2005, 21,
496.

6036 Inorganic Chemistry, Vol. 48, No. 13, 2009
Fan et al.
n=1.5, 1; Ar=2,6-iPr2C6H3, n=0, 2; Ar=2,6-Me2C6H3,
n=1, 3; Ar=2-MeC6H4, n=1, 4; Ar=4-MeC6H4, n=1, 5;
Ar=2,4,6-Me3C6H2, n=1, 6; Ar=2,6-Et2C6H3, n=0, 7).
Experimental Section
Materials and Methods. All manipulations of air- and moist-
ure-sensitive compounds were performed under an atmosphere
of nitrogen using standard Schlenk techniques. 1H NMR spec-
tra were recorded on a Varian Mercury 300 MHz spectrometer.
IR spectra were recorded on a Nicolet Impact 410 FTIR
spectrometer using KBr pellets. Elemental analyses were per-
formed on a Perkin-Elmer 240c element analyzer. UV-vis
spectra were obtained on a Perkin-Elmer Lambda 20 spectro-
meter. Luminescence spectra were measured on a Perkin-Elmer
LS55 Luminescence spectrometer at room temperature. Fluor-
escence lifetimes were measured with a Lecroy Wave Runner
6100 Digital Oscilloscope (1 GHz) using a 350 nm laser (pulse
width=4 ns) as the excitation source (Continuum Sunlite OPO).
Solvents were refluxed over an appropriate drying agent and
distilled and degassed prior to use. Aniline, 2,6-diisopropylani-
line, 2,6-dimethylaniline, 2-methylaniline, 4-methylaniline,
2,4,6-trimethylaniline, and 2,6-diethylaniline were purchased
from Aldrich Chemical Company and used as received.
2,6-Diacetylpyridine was prepared according to a published
procedure.18 Free ligands, 2,6-(ArNdCMe)2C5H3N [Ar =
C6H5, L1; Ar=2,6-iPr2C6H3, L2; Ar=2,6-Me2C6H3, L3; Ar=
2-MeC6H4, L4; Ar=4-MeC6H4, L5; Ar=2,4,6-Me3C6H2, L6;
Ar=2,6-Et2C6H3, L7] were synthesized according to published
procedures in good yield by the condensation of 2,6-diacetyl-
pyridine with the corresponding aniline in refluxing absolute
methanol in the presence of a catalytic amount of formic acid
(Scheme 1).13,14
Syntheses. Synthesis of 2,6-Bis[(1-phenylimino)ethyl]pyridi-
neHgCl2 1.5CH3CN (1). A mixture of L1 (113 mg, 0.36 mmol)
3
and HgCl2 (98 mg, 0.36 mmol) in CH3CN (20 mL) was stirred
under nitrogen at room temperature for 12 h. Evaporation of the
solvent gave the crude product as a yellowish powder. Pure
product 1 was obtained in 77% yield (179 mg) by recrystalliza-
tion from CH3CN/CH2Cl2 (2:1). 1H NMR (300 MHz, CD3CN):
δ 8.49 (s, 3 H, Py-H), 7.51-7.12 (m, 10 H, Ar-H), 2.52 (s, 6 H,
NdCMe). 13C NMR (CD3CN, 1H gated decoupled): δ 164.79
(NdC), 148.83 (Py-Co), 147.56 (Ar-Cip), 142.52 (Ar-Co), 129.33
(Ar-Cp), 128.35 (Py-Cp), 126.02 (Py-Cm), 121.05 (Ar-Cm), 17.78
(NdC-Me). IR (KBr, cm-1): 3089 (w), 3019 (w), 2970 (w), 2920
(w), 2247 (w), 1643 (s), 1594 (s), 1485 (s), 1448 (m), 1368 (s), 1247
(s), 1225 (s), 1185 (w), 1148 (w), 1011 (w), 906 (w), 816 (s), 775
(s), 697 (s), 573 (w), 532 (w). Elem anal. calcd for
Figure 1. Top: Molecular structure of complex 1 (the other molecule
and CH3CN molecules have been omitted for clarity). Bottom: Packing
diagram of complex 1 along the c axis. Hydrogen bonds are indicated by
dashed lines.
bis(imino)pyridyl ligands were reported by Brookhart et al. and
Gibson et al.14-16 These iron and cobalt complexes exhibit high
activity for olefin polymerization. Recently, we synthesized a
number of bis(imino)pyridine zinc(II) and cadmium(II) com-
plexes and explored the electronic effect of substituents at the
aryl-ring of the bis(imino)pyridyl ligand on the luminescent
properties of these complexes.13 To fulfill full-color electro-
luminescent displays, three color components, that is, red,
green, and blue, must be available. Stable blue luminescent
compounds used for electroluminescent devices are still rare
and very challenging to prepare. In this work, we report the
syntheses, structures, and blue luminescent properties of seven
new mercury(II) complexes with 2,6-bis(imino)pyridyl ligands,
C21H19N3HgCl2 1.5CH3CN: C, 44.59; H, 3.66; N, 9.75. Found:
C, 44.19; H, 3.60; N, 9.44.
3
Synthesis of 2,6-Bis[1-(2,6-diisopropylphenylimino)ethyl]pyri-
dineHgCl2 (2). Complex 2 was prepared in the same way as
described for 1. Yield: 78%. 1H NMR (300 MHz, CD3CN): δ
8.52 (s, 3 H, Py-H), 7.26-7.18 (m, 6 H, Ar-H), 2.87 (sept, J = 6.8
Hz, 4 H, CHMe2), 2.39 (s, 6 H, NdCMe), 1.23 (dd, J = 6.8 Hz,
24 H, CHMe2). IR (KBr, cm-1): 3088 (w), 3059 (w), 2960 (s),
2925 (m), 2865 (m), 1638 (s), 1581 (s), br 1455 (s), 1366 (s), 1329
(m), 1301 (m), 1244 (s), 1202 (s), 1105 (m), 1056 (m), 978 (w), 936
(m), 819 (m), 793 (s), 774 (s), 759 (w), 715 (w), 634 (w), 554 (w).
Elem anal. calcd for C33H43N3HgCl2: C, 52.62; H, 5.75; N, 5.58.
Found: C, 52.88; H, 5.96; N, 5.89.
2,6-(ArNdCMe)2C5H3NHgCl2 nCH3CN (Ar= C6H5,
3
(14) (a) Small, B. L.; Brookhart, M.; Bennett, A. M. A. J. Am. Chem. Soc.
1998, 120, 4049. (b) Britovsek, G. J. P.; Gibson, V. C.; Kimberley, B. S.;
Maddox, P. J.; McTavish, S. J.; Solan, G. A.; White, A. J. P.; Williams, D. J.
J. Chem. Soc., Chem. Commun. 1998, 849. (c) Gibson, V. C.; Redshaw, C.;
Solan, G. A. Chem. Rev. 2007, 107, 1745.
(15) (a) Bennett, A. M. A. Chemtech 1999, 29, 24. (b) Lttel, S. D.;
Johnson, L. K. Chem. Rev. 2000, 100, 1169. (c) Small, B. L.; Marcucci, A.
J. Organometallics 2001, 20, 5738. (d) Pelascini, F.; Wesolek, M.; Peruch, F.;
Lutz, P. J. Eur. J. Inorg. Chem. 2006, 4309.
Synthesis of 2,6-Bis[1-(2,6-dimethylphenylimino)ethyl]pyridi-
neHgCl2 CH3CN (3). Complex 3 was prepared in the same way
3
(17) (a) Mahmoudkhani, A. H.; Langer, V.; Casari, B. M. Acta Crystal-
logr. 2001, E57, m393. (b) Fan, R.-Q.; Wang, P.; Yang, Y.-L.; Lv, Z.-W. Acta
Crystallogr. 2007, E63, m2501. (c) Jia, W. L.; Liu, Q. D.; Song, D; Wang, S.
Organometallics 2003, 22, 321.
(16) (a) Abu-Surrah, A. S.; Lappalainen, K.; Piirone, U.; Lehmus, P.;
::
Repo, T.; Leskela, M. J. Organomet. Chem. 2002, 648, 55. (b) Gibson, V. C.;
Spitzmesser, S. K. Chem. Rev. 2003, 103, 283.
(18) Zhong, J. Z.; Wang, F. Acta Acad. Med. Jiangxi 1999, 39, 93.

Article
Inorganic Chemistry, Vol. 48, No. 13, 2009 6037
Figure 2. Top: Molecular structure of complex 2. Bottom: Packing diagram of complex 2 along the c axis. Hydrogen bonds are indicated by dashed lines.
as described for 1. Yield: 80%. 1H NMR (300 MHz, CD3CN): δ
8.54 (s, 3 H, Py-H), 7.22-6.87 (m, 6 H, Ar-H), 2.41 (s, 6 H,
NdCMe), 2.19 (s, 12 H, CMe). IR (KBr, cm-1): 3084 (w), 3019
(w), 2960 (w), 2920 (w), 1646 (s), 1583 (s), 1466 (s), 1440 (m),
1371 (s), 1251 (s), 1215 (s), 1093 (w), 1036 (w), 979 (w), 919 (w),
817 (m), 781 (m), 737 (w), 697 (w), 580 (w). Elem anal. calcd for
Synthesis of 2,6-Bis[1-(2,4,6-trimethylphenylimino)ethyl]pyri-
dineHgCl2 CH3CN (6). Complex 6 was prepared in the
3
same way as described for 1. Yield: 80%. 1H NMR (300
MHz, CD3CN): δ 8.60 (s, 3 H, Py-H), 6.91 (s, 4 H, Ar-H),
2.50 (s, 6 H, NdCMe), 2.24 (s, 6 H, CMe), 2.01 (s, 12 H,
CMe). IR (KBr, cm-1): 3086 (w), 2950 (w), 2918 (m), 2860
(w), 2737 (w), 1642 (s), 1584 (s), 1474 (s), 1435 (m), 1370 (m),
1247 (s), 1222 (s), 1157 (w), 1098 (w), 1007 (w), 846 (s),
807 (s), 736 (w), 645 (w), 561 (w). Elem anal. calcd for
C25H27N3HgCl2 CH3CN: C, 47.55; H, 4.43; N, 8.21. Found: C,
47.38; H, 4.51; N, 8.15.
Synthesis of 2,6-Bis[1-(2-methylphenylimino)ethyl]pyridi-
3
C27H31N3HgCl2 CH3CN: C, 49.05; H, 4.83; N, 7.89. Found:
C, 48.98; H, 4.81; N, 7.75.
Synthesis of 2,6-Bis[1-(2,6-diethylphenylimino)ethyl]pyridi-
neHgCl2 CH3CN (4). Complex 4 was prepared in the same
3
3
way as described for 1. Yield: 82%. 1H NMR (300 MHz,
CD3CN): δ 8.50 (s, 3 H, Py-H), 7.30-6.61 (m, 8 H, Ar-H),
2.43 (s, 6 H, NdCMe), 2.22 (s, 6 H, CMe). IR (KBr, cm-1): 3078
(w), 3019 (w), 2920 (w), 1646 (s), 1581 (s), 1482 (s), 1457 (m),
1368 (m), 1249 (s), 1225 (s), 1200 (m), 1113 (w), 1044 (w), 1011
(w), 816 (s), 786 (s), 753 (s), 718 (m), 666 (w), 443 (m). Elem anal.
neHgCl2 CH3CN (7). Complex
7 was prepared in the
3
same way as described for 1. Yield: 82%. 1H NMR (300
MHz, CD3CN): δ 8.47 (s, 3 H, Py-H), 7.22-7.18 (m, 6 H,
Ar-H), 2.68 (q, J =6.8 Hz, 8 H, Ar-CH2Me), 2.36 (s, 6 H,
NdCMe), 1.09 (t, J =6.8 Hz, 12 H, Ar-CH2Me). IR (KBr,
cm-1): 3067 (w), 2964 (s), 2938(m), 2880 (m), 1622 (m),
1589 (s), 1447 (s), 1369 (s), 1319 (m), 1271 (s), 1213 (s),
1109 (w), 1038 (w), 985 (w), 868 (w), 810 (s), 771 (s),
745 (w), 641 (w), 550 (w). Elem anal. calcd for C29H35N3-
HgCl2: C, 49.97; H, 5.06; N, 6.03. Found: C, 50.08; H, 5.31;
N, 6.25.
calcd for C23H23N3HgCl2 CH3CN: C, 45.91; H, 4.01; N, 8.57.
Found: C, 45.68; H, 4.38; N, 8.29.
Synthesis of 2,6-Bis[1-(4-methylphenylimino)ethyl]pyridi-
3
neHgCl2 CH3CN (5). Complex
5 was prepared in the
3
same way as described for 1. Yield: 85%. 1H NMR (300
MHz, CD3CN): δ 8.25 (s, 3 H, Py-H), 7.11-6.84 (m, 8 H,
Ar-H), 2.32 (s, 6 H, NdCMe), 2.20 (s, 6 H, CMe). IR (KBr,
cm-1): 3079 (w), 3025 (w), 2915 (w), 2860 (w), 1638 (m),
1583 (m), 1505 (s), 1458 (m), 1368 (m), 1250 (s), 1226 (s),
1104 (w), 1013 (w), 842 (m), 813 (m), 762 (w), 734 (s), 707
(w), 630 (w), 542 (w), 514 (w). Elem anal. calcd for
X-Ray Crystallography. The single-crystal X-ray diffraction
data for complexes 1-6 were collected on a Rigaku R-AXIS
RAPID IP or a Bruker Smart Apex CCD diffractometer
equipped with graphite-monochromated Mo KR radiation
˚
C23H23N3HgCl2 CH3CN: C, 45.91; H, 4.01; N, 8.57. Found:
C, 45.88; H, 4.11; N, 8.75.
(λ = 0.71073 A), operating at 293 ( 2 K. The structures were
3
solved by direct methods and refined by full-matrix

6038 Inorganic Chemistry, Vol. 48, No. 13, 2009
Fan et al.
Figure 3. Top: Molecular structure of complex 3 (the CH3CN molecule has been omitted for clarity). Bottom: Packing diagram of complex 3 along the c
axis. Hydrogen bonds are indicated by dashed lines.
least-squares based on F2 using the SHELXTL 5.1 software
package.19 The hydrogen atoms residing on the carbon atoms
were located geometrically. All non-hydrogen atoms were re-
fined anisotropically. Crystallographic data are given in Table 1.
The CCDC reference numbers for complexes 1-6 are 232414,
232419, 232420, 232415, 720498, and 720499, respectively.
Crystallographic data are given in Table 1.
Crystal Structures. Crystals of 1-6 suitable for X-ray
structural determination were grown from an acetoni-
trile/dichloromethane (2:1) solution (1, 3, 4, and 5),
from a concentrated dichloromethane solution (2), or
from a concentrated tetrahydrofuran solution (6). The
molecular structures of complexes 1-6 are shown in
Figures 1-6, respectively, and selected bond lengths
and angles are presented in Table 2.
Results and Discussion
Complexes 1, 2, 3, 5, and 6 possess structures with
approximate Cs symmetry about a plane bisecting the
central pyridine ring and containing the mercury atom
and two chlorine atoms, while complex 4 adopts C2
symmetry. The central mercury atom in 1-6 is coordi-
nated to five groups, and the geometry about the mercury
atom is a distorted trigonal bipyramid, with the equator-
ial plane defined by the N(2)(pyridine), Cl(1), and Cl(2)
atoms and the N(1) and N(3)(imino) atoms in the axial
position, in which Hg-Cl(2) bond distances are signifi-
cantly longer than that of Hg-N(2); moreover, Hg-N(3)
bond distances are still longer than that of Hg-N(1).
There are two independent complex molecules and three
Synthesis. The bis(imino)pyridine mercury complexes
1-7 were synthesized in good yield (ca. 77-85%) as air-
stable yellowish solids by reactions of the corresponding
bis(imino)pyridyl ligands with HgCl2 in CH3CN solution
at room temperature (Scheme 1). All compounds were
1
characterized by H NMR, UV/vis, and IR spectrosco-
pies as well as elemental analyses. Molecular structures of
complexes 1-6 were determined by single-crystal X-ray
diffraction analyses.
(19) SHELXTL NT Crystal Structure Analysis Package, version 5.10;
Bruker AXS, Analytical X-ray System: Madison, WI, 1999.

Article
Inorganic Chemistry, Vol. 48, No. 13, 2009 6039
two independent molecules and two acetonitrile mole-
cules in the asymmetric unit in mercury complexes 4 and
6, respectively. The dihedral angles in one molecule in 1
between the phenyl rings and the plane formed by the
three coordinated nitrogen atoms are 75.6(4) and 80.4
(5)°, larger than those in the other molecule [60.0(3) and
66.5(3)°, respectively]. The dihedral angles in 2-6 ranging
between the phenyl rings and plane formed by three
coordinated nitrogen atoms are 75.3(4) and 89.3(3)°.
The dihedral angles between the two phenyl rings are
73.4(4)° and 83.0(4)° in the two molecules in 1. The
dihedral angles between the two phenyl rings are oriented
essentially orthogonally in 2-6 [ranging between 80.6(3)°
and 89.0(2)°]. The mean deviation of the mercury atoms
in 1-6 from the equatorial planes is 0.015, 0.032, 0.019,
˚
˚
0.011, 0.012, and 0.022 A (0.014, 0.012, and 0.010 A for
the other molecule in 1, 4 and 6, respectively), respec-
tively, and the axial Hg-N(imino) bonds subtend angles
of 134.4(3)°, 126.6(2)°, 135.6(2)°, 134.8(3)°, 133.9(1)°,
and 135.3(2)° , respectively [135.2 (1)°, 135.5(3)°, and
134.3(2)° for the other molecule in 1, 4, and 6, respec-
tively]. The mercury atoms in 1-6 deviate by 0.113, 0.740,
˚
0.120, 0.054, 0.032, and 0.017 A, respectively (0.110,
˚
0.001, and 0.180 A for the other molecule in 1, 4, and 6,
Figure 4. Top: Molecular structure of complex 4 (the other molecule and
CH3CN molecules have been omitted for clarity). Bottom: Packing diagram
of complex 4 along the caxis. Hydrogen bonds are indicated by dashed lines.
respectively), from the coordinated plane. The Hg-N
(pyridine) bonds in 1-6 range from 2.354(1) to 2.399-
(6) A, while the distances between the mercury atom and
˚
the imino nitrogen atoms in the six complexes are almost
˚
the same [2.429(9) and 2.443(9) A] in 1 [2.449(1) and
˚
2.477(1) A for the other molecule in 1], [2.514(6) and
˚
2.533(7) A] 2, [2.475(5) and 2.487(6) A] 3, [2.421(9) and
˚
˚
2.457(9) A] 4 [2.424(10) and 2.443(9) A for the other
˚
˚
molecule in 4], [2.461(4) and 2.452(4) A] 5, and [2.490(7)
˚
˚
and 2.457(6) A] 6 [2.498(6) and 2.450(6) A for the other
molecule in 6]. In each complex, the Hg-N(pyridine)
bond is significantly shorter than the Hg-N(imino)
bonds, with the formal double-bond character of the
imino linkages N(1)-C(1) and N(3)-C(7) being retained
˚
[CdN distances in the range 1.249(13)-1.324(11) A].
There are no intermolecular packing features of interest
in any of the six complexes. However, the structures of
complexes 1-6 are stabilized by the hydrogen bonds
between the Cl atom and C atoms of the adjacent com-
plexes (Figures 1-6 bottom), as indicated by the distances
˚
of Cl C, 3.453-3.828 A, and the bond angles of
3 3 3
Cl
H
C, 133.65-165.87°, which are similar to re-
3 3 3 3 3 3
sults from the literature reported previously.17a,17b The
Cl C bond distances and Cl
listed in Table 3.
H
C bond angles are
3 3 3
3 3 3 3 3 3
Luminescent Properties. Table 4 presents the absorp-
tion and emission data for the new complexes 1-7 in a
dichloromethane solution and in the solid state at room
temperature together with those of ligands L1-L7. The
seven complexes show two main absorption bands (Fig-
ures 7), which are similar to those in ligands L1-L7 in the
UV region. The electronic absorption spectra of the
complexes show low energy absorption bands at ca.
346-364 nm (329-347 nm for ligands L1-L7) and higher
energy absorption bands at ca. 288-303 nm (281-300
nm for ligands L1-L7), attributed to ligand-centered
π f π* transitions. The electronic absorption spectra of
the complexes compared with ligands are red-shifted, for
the metal perturbed intraligand π f π* transition of the
Figure 5. Top: Molecular structure of complex 5 (the CH3CN molecule
has been omitted for clarity). Bottom: Packing diagram of complex 5
along the a axis. Hydrogen bonds are indicated by dashed lines.
acetonitrile molecules in the asymmetric unit in mercury
complex 1. Complexes 3 and 5 contain one independent
molecule and one acetonitrile molecule, whereas there are

6040 Inorganic Chemistry, Vol. 48, No. 13, 2009
Fan et al.
Figure 6. Top: Molecular structure of complex 6 (the other molecule and CH3CN molecules have been omitted for clarity). Bottom: Packing diagram of
complex 6 along the c axis. Hydrogen bonds are indicated by dashed lines.
˚
Table 2. Selected Bond Lengths (A) and Angles (deg) for 1-6
1
2
3
4
5
6
molecule1-1 molecule1-A
molecule4-1 molecule4-A
molecule7-1 molecule7-A
Hg-N(2)
2.382(8)
2.429(9)
2.389(3)
2.443(8)
2.434(3)
1.271(14)
1.249(13)
67.4(3)
2.354(1)
2.449(1)
2.398(1)
2.477(1)
2.427(1)
1.281(1)
1.275(10)
67.6(1)
2.399(6)
2.514(6)
2.365(3)
2.533(7)
2.418(3)
1.266(11)
1.291(11)
65.7(2)
2.354(6)
2.475(5)
2.414(2)
2.487(6)
2.412(2)
1.259(10)
1.275(9)
67.4(2)
2.376(9)
2.421(9)
2.396(4)
2.457(9)
2.420(3)
1.317(11)
1.300(14)
67.6(3)
2.382(8)
2.424(10)
2.416(3)
2.443(9)
2.426(3)
1.317(11)
1.324(11)
67.9(3)
2.387(4)
2.461(4)
2.416(1)
2.452(4)
2.424(1)
1.265(6)
1.264(6)
67.1(1)
2.370(6)
2.490(7)
2.430(2)
2.457(6)
2.442(2)
1.272(9)
1.265(9)
67.6(2)
2.387(6)
2.498(6)
2.423(2)
2.450(6)
2.445(2)
1.286(9)
1.287(9)
67.1(2)
Hg-N(1)
Hg-Cl(1)
Hg-N(3)
Hg-Cl(2)
N(1)-C(1)
N(3)-C(7)
N(2)-Hg-N(1)
N(2)-Hg-Cl(1) 125.8(2)
N(1)-Hg-Cl(1) 104.7(2)
N(2)-Hg-N(3)
N(1)-Hg-N(3)
129.1(1)
101.9(1)
67.7(1)
135.2(1)
103.3(1)
109.1(1)
98.5(1)
134.5(2)
98.3(2)
65.4(2)
126.6(2)
100.9(2)
94.4(2)
101.1(2)
131.0(1)
102.6(2)
122.1(2)
102.8(2)
68.3(2)
135.6(2)
97.5(2)
115.7(2)
99.9(2)
122.1(1)
102.0(2)
119.8(2)
100.5(2)
67.2(3)
134.8(3)
100.1(2)
113.6(2)
98.4(2)
124.5(2)
101.7(2)
67.6(3)
135.5(3)
103.1(2)
115.9(2)
101.0(2)
119.6(1)
98.1(2)
120.2(1)
101.2(1)
66.8(1)
133.9(1)
100.7(1)
115.2(1)
100.4(1)
124.6(1)
99.6(1)
121.7(2)
99.8(2)
67.7(2)
135.3(2)
102.9(2)
118.8(2)
100.9(2)
119.5(8)
100.6(2)
127.0(2)
102.7(2)
67.6(2)
134.3(2)
100.0(2)
114.4(2)
99.5(2)
67.1(3)
134.4(3)
Cl(1)-Hg-N(3) 104.1(2)
N(2)-Hg-Cl(2) 109.8(2)
N(1)-Hg-Cl(2)
Cl(1)-Hg-Cl(2) 124.4(1)
N(3)-Hg-Cl(2) 97.5(3)
94.5(2)
121.8(1)
98.8(1)
126.6(1)
100.7(2)
118.5(8)
103.5(2)
bis(imino)pyridyl unit. The energy trend of this band for
the complex 1-7 series is found to follow the order 5 <
6< 3 < 4, 7 < 2 < 1 (similar to ligands L1-L7). It is very
interesting that the electron-donating ability of the alkyl
group (2,4,6-trimethylphenyl > 2,6-dimethylphenyl >
2-methylphenyl, 2,6-diethylphenyl > 2,6-diisopropylphe-
nyl > phenyl) is in the line with the energy trend, with
the exception of complex 5. Complex 5 shows that
the lowest absorption energy attributable to lower
steric hindrance on the p-methyl-substituted phenyl

Article
Inorganic Chemistry, Vol. 48, No. 13, 2009 6041
ring of the bis(imino)pyridyl metal complex leads to a
highly coplanar situation and an absorption energy red
shift.
the order 5 < 6 < 3 < 4, 7 < 2 < 1 is observed, again in
line with the electron-donating ability of the alkyl and
with steric effects. The quantum yields of all compounds
have been determined in solution (Table 4). It was found
that the quantum yields of Hg(II) complexes 1-7 are
slightly higher than those of free ligands L1-L7 and are
lower than those of their Zn(II) complexes.15b These
results can be easily understood considering the following
factors: The chelation of the ligand to the metal center
increases the rigidity of the ligand and thus reduces the
loss of energy by thermal vibrational decay and therefore
increases the emission efficiency. On the other hand, the
Hg(II) cation and the chloride anions can quench the
fluorescence and result in luminescence decay. These
emission bands are dominated by fluorescence. The
fluorescence decay lifetimes of 1-7 were found to range
from 2.11 to 2.95 ns (0.62-0.95 ns for ligands L1-L7;
Table 4). However, in the solid state at room temperature,
complexes 1-7 exhibit a bright greenish-blue color emis-
sion band with an emission maximum at λmax = 485, 486,
488, 486, 498, 492, and 486 nm, respectively (λmax= 471,
475, 480, 476, 485, 480, and 475 nm for L1-L7), red-
shifted about 80 nm (ca. 100 nm for L1-L7) from that of
the emission in solution (Figure 9). This dramatic red
shifts of the emission energy of complexes 1-7 from
solution to solid are probably caused by the intermole-
cular hydrogen bonds in solid-state complexes 1-7,
which effectively decreases the energy gap. The existence
of intermolecular hydrogen bonds in complexes 1-6, as
shown by the crystal structures, may be a factor contri-
buting to the red shift.17c
Complexes 1-7 have blue emission in a degassed
CH2Cl2 solution at room temperature, with λmax = 395,
400, 407, 403, 427, 415, and403nm, respectively(Figure8;
λmax = 368, 375, 381, 378, 405, 388, and 380 nm, for
L1-L7). Similar to the electronic absorption data,
their emission energies are found to depend on the
electron donation of the alkyl substituents on the aryl
rings of the bis(imino)pyridyl ligand and steric effects.
For the complex 1-7 series, an emission energy trend in
˚
Table 3. Hydrogen-Bond Geometry (A, deg) for 1-6
D-H
A
D
A
D-H
3 3 3
A
3 3 3
3 3 3 3
1
Cl1-H C20
3.681
3.742
3.716
3.621
3.681
3.650
3.453
3.643
3.828
3.651
3.763
3.625
3.621
3.662
3.761
3.686
3.652
3.636
3.643
3.728
138.23
154.16
160.42
159.67
149.26
164.27
133.65
162.42
163.45
141.77
147.22
146.44
161.84
163.31
147.15
147.37
165.02
141.95
159.66
165.87
3 3 3
Cl2-H C12
3 3 3
Cl2-H C12A
3 3 3
Cl2-H C3A
3 3 3
Cl1A-H C9
3 3 3
Cl2A-H C5
3 3 3
2
3
Cl1-H C3
3 3 3
Cl1-H C3
3 3 3
Cl1-H C9
3 3 3
Cl2-H C8
3 3 3
4
Cl1-H C23A
3 3 3
Cl2-H C21
3 3 3
Cl2-H C3A
3 3 3
Cl2A-H C3
3 3 3
5
6
Cl1-H C8
3 3 3
Cl1-H C9
3 3 3
Cl2-H C5
3 3 3
Cl1-H C9
3 3 3
To further understand the origin of the red shift of the
absorption energy from the free ligand to the complex, we
Cl2-H C5
3 3 3
Cl2A-H C5A
3 3 3
Table 4. Photoluminescent Data for 1-7 and L1-L7a
absorption (nm)
ε/dm3 mol-1 cm-1
excitation
(λmax, nm)
emission
(λmax, nm)
quantum
yields (Φ)b
decay lifetime
(τ, ns)
compound
conditions
1
2
288 (15522), 346 (3017)
293 (15590), 352 (3221)
300 (15986), 360 (3491)
296 (15716), 355 (3356)
303 (15907), 364 (5973)
302 (15846), 360 (2661)
296 (15741), 356 (2559)
281 (16025), 329 (7485)c
284 (16180), 334 (7640)c
291 (16528), 340 (7998)c
287 (16335), 337 (7843)c
300 (26463), 347 (18838)
296 (21090), 342 (12340)
287 (16418), 338 (7862)
395
485
400
486
407
488
403
486
427
498
415
492
403
486
368c
471c
375c
475c
381c
480c
378c
476c
405
485
388
480
380
475
0.028
0.032
0.037
0.034
0.035
0.042
0.032
0.005
0.008d
0.009d
0.008
0.008
0.012
0.009
2.11
2.25
2.88
2.60
2.65
2.95
2.28
0.62
0.76d
0.89d
0.73
0.80
0.95
0.80
CH2Cl2, 298 K
solid, 298K
CH2Cl2, 298 K
solid, 298K
CH2Cl2, 298 K
solid, 298K
CH2Cl2, 298 K
solid, 298 K
CH2Cl2, 298 K
solid, 298 K
CH2Cl2, 298 K
solid, 298 K
CH2Cl2, 298 K
solid, 298 K
CH2Cl2, 298 K
solid, 298 K
CH2Cl2, 298 K
solid, 298 K
CH2Cl2, 298 K
solid, 298 K
CH2Cl2, 298 K
solid, 298 K
CH2Cl2, 298 K
solid, 298 K
CH2Cl2, 298 K
solid, 298 K
CH2Cl2, 298 K
solid, 298 K
330
330
330
330
330
330
330
330
330
330
330
330
330
330
3
4
5
6
7
L1
L2
L3
L4
L5
L6
L7
a Concentration: [M] = 1 ꢀ 10-5 M. b Determined using quinine sulfate in 0.1 M sulphuric acid as a standard. c Photoluminescent data of L1-L4 from
ref 15. d Photoluminescent data of L1-L4 from ref 15.

6042 Inorganic Chemistry, Vol. 48, No. 13, 2009
Fan et al.
Figure 9. Emission spectra of complexes 1-7 in the solid state at 298 K.
Table 5. Primary Electron Transitions of L2 and 2 at the TD-DFT/TZP Level
Figure 7. UV-vis absorption spectra of complexes 1-7.
Ege
compound (ev)
λ
(nm)
major
contributions
fos
L2
2
4.2703 290.30 0.0770 HOMO-6 f LUMO (43.5%)
3.8633 320.93 0.0170 HOMO-4 f LUMO+1 (91.7%)
3.4068 363.93 0.0515 HOMO-1 f LUMO+2 (96.1%)
3.3919 365.53 0.0011 HOMO f LUMO+2 (72.2%)
For ligand L2, the electron transitions are complicated,
and there are many transitions with small oscillator
strengths that can be obtained. It is interesting to note
that the intense bands of both ∼280 and ∼330 nm in the
experiments are well reproduced, that is, respectively
290.30 nm (HOMO-6 f LUMO) and 320.93 nm
(HOMO-4 f LUMO+1) in computations, and mainly
come from π f π* transitions in the center pyridyl ring. In
contrast, the electron transitions for complex 2 are
relatively simple and dominantly come from the frontier
molecular orbitals. As can be seen, the electron densities
of HOMO-1 and HOMO for complex 2 are located
toward the conjugated CdN bridge and the phenyl
ring, while those of LUMO+2 are located on the
HgCl2 subunit in the center part of the whole molecule.
Computationally, the intense absorption band (∼365 nm)
for complex 2 compares well with the experimental one at
∼350 nm; however, the band at ∼290 nm in the experi-
ment is difficult to predict and might be attributed to the
insufficiency of the TD-DFT method employed.23
As given in Figure 10, the intense bands including
363.93 nm originating from an almost pure HOMO-
1 f LUMO+2 (54A00 f 67A0) and 365.53 nm coming
mainly from HOMO f LUMO+2 (65A0 f 67A0)
are characteristic for metal-to-ligand charge transfer
excitation from the peripheral phenyl ring to the center
Hg/Cl atoms. Obviously, the electron densities on
the metal atom in 67A0 (LUMO+2) are not small, which
indicates that Hg(II) plays an important role of electronic
transmission during the transition. In addition, the
shift of absorption energy of the complex in comparison
to the free ligand is consistent with the experimental
observation.
Figure 8. Emission spectra of complexes 1-7 in CH2Cl2 solution at
298 K.
performed ab initio calculations (ADF2008)20 for the free
ligand L2 and complex 2 based on the time-dependent
density functional theory (TD-DFT) GGA-PW91 meth-
od, with the TZP basis set for all atoms.21 The geometric
parameters obtained from X-ray diffraction analyses
were fully optimized in conjunction with the COSMO22
solvent model (CH2Cl2, ε = 8.9), and the symmetries of
both compounds are a little enhanced, that is, C2 and Cs
for the L2 and complex 2, respectively. The properties of
the significant transitions are reported in Table 5, and the
qualitative MO diagram and shapes of the spectroscopi-
cally relevant molecular orbitals are plotted in Figure 10.
(20) ADF 2008.01; Department of Theoretical Chemistry, Vrije Univer-
siteit: Amsterdam.(a) Baerends, E. J.; Ellis, D. E.; Ros, P. Chem. Phys. 1973,
2, 41. (b) Versluis, L.; Ziegler, T. J. Chem. Phys. 1988, 88, 322. (c) Te Velde,
G.; Baerends, E. J. J. Comput. Phys. 1992, 99, 84. (d) Baerends, E. J. Theor.
Chem. Acc. 1998, 99, 391.
(21) The internal electrons (1s for Cl, C, and N; 1s to 4d for Hg) were
described by means of single Slate functions. The quasi-relativistic forzen
core shells generated by the auxiliary program DIRAC were used to correct
the core potential within the ZORA formalism.
:: ::
(22) (a) Klamt, A.; Schuurmann, G. J. Chem. Soc., Perkin Trans. 1993, 2,
(23) Cramariuc, O.; Hukka, T. I.; Rantala, T. T.; Lemmetyinen, H. J.
Phys. Chem. A 2006, 110(45), 12470.
799. (b) Klamt, A. J. Chem. Phys. 1995, 99, 2224.

Article
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Figure 10. Qualitative MO diagram and shapes of the spectroscopically relevant molecular orbitals. The orbital labels correspond to those in Table 5.
Conclusion
Acknowledgment. This work was supported by the
National Natural Science Foundation of China (Grant
Nos. 20771030, 20671025, and 60778019), Young Foun-
dation of Heilongjiang Province in China (QC06C029),
and The Research Fund for the Doctoral Program of
Higher Education (20070213005). We thank Dr. Yongq-
ing Qiu in Northeast Normal University for providing
quantum chemical calculations.
A series of mercury(II) bis(imino)pyridyl complexes
has been synthesized and characterized. Complexes 1-7
have fluorescent emission at 395-427 nm in a dichloro-
methane solution at room temperature. Complexes 1-7
have fluorescent emission bands in the solid state at room
temperature, with λmax = 485, 486, 488, 486, 498, 492,
and 486 nm for 1-7, respectively. Their luminescent proper-
ties show that they are a new class of luminescent metal
compounds with potential applications in optoelectronic
devices.
Supporting Information Available: A crystallographic infor-
mation file (CIF) is provided. This material is available free of
charge via the Internet at http://pubs.acs.org.