Structures and vibrational spectra of the N-benzoyl N′- dialkylthiourea derivative and their complexes with Hg(II)

Article abstract of DOI:10.1016/j.molstruc.2005.03.046

The complex Hg (MTCB)₂ (MTCB=N-(morpholinothiocarbonyl) benzamide) and Hg (PTCB)₂ (PTCB=N-(piperidylthiocarbonyl) benzamide) have been synthesized and characterized by elemental analysis, FT-IR, FT-Raman spectra and NMR methods. The complex, Hg (MTCB)₂, crystallizes in the triclinic space group P1?, with Z=2. Unit cell parameters, a=10.3621(11) ?, b=11.5738(11) ?, c=12.7722(7) ?, α=64.493(8)°, β=66.132(8)°, γ=85.811(11)°, V=1254.7(2) ?³. The FT-Infrared and FT-Raman spectra were used in study of the structures of MTCB, PTCB and their complexes with mercury cation, which were agreement with the result of X-ray diffraction.

Full text of DOI:10.1016/j.molstruc.2005.03.046

Journal of Molecular Structure 749 (2005) 89–95
www.elsevier.com/locate/molstruc
Structures and vibrational spectra of the N-benzoyl N0-dialkylthiourea
derivative and their complexes with Hg(II)
*
Zhou Weiqun , Yang Wen, Qiu Lihua, Zhang Yong, Yu Zhengfeng
Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry and Chemical Engineering, Suzhou University,
1 shizi St Suzhou, Suzhou 215006, People’s Republic of China
Received 13 February 2005; revised 21 March 2005; accepted 29 March 2005
Available online 26 May 2005
Abstract
The complex Hg (MTCB)2 (MTCBZN-(morpholinothiocarbonyl) benzamide) and Hg (PTCB)2 (PTCBZN-(piperidylthiocarbonyl)
benzamide) have been synthesized and characterized by elemental analysis, FT-IR, FT-Raman spectra and NMR methods. The complex, Hg
ꢀ
˚
˚
(MTCB)2, crystallizes in the triclinic space group P1, with ZZ2. Unit cell parameters, aZ10.3621(11) A, bZ11.5738(11) A,
3
˚
˚
cZ12.7722(7) A, aZ64.493(8)8, bZ66.132(8)8, gZ85.811(11)8, VZ1254.7(2) A . The FT-Infrared and FT-Raman spectra were used
in study of the structures of MTCB, PTCB and their complexes with mercury cation, which were agreement with the result of X-ray
diffraction.
q 2005 Elsevier B.V. All rights reserved.
1. Introduction
complexes with N-benzoyl-N0, N0-dialkylthioureas. The
N-benzoyl-N0, N0-dialkylthioureas ligands exhibit various
donor ability in coordination compounds. The most
common type of ligand bonding to the metal centre is
through the S atoms and carbonyl oxygen atoms [8,9].
On the basis of spectroscopic studies of complexes in the
solution and crystalline state, it was found that the
complexes with Ni(II), Pt(II), Cu(II), Zn(II) and Co(II) are
coordinated. Such five-membered chelate ring containing S,
O donor atoms were established by X-ray analysis for the
Ni(II) and Pt(II) complexes [9,16]. Mercury (II) complexes
containing sulfur were described and the tetrahedral
geometry postulated on the basis of IR and NMR data
[17,18], and the experiments of X-ray diffraction technol-
ogy have also made sure [19–22]. There is no structural
studies on the mercury (II) complexes with N-benzoyl-N0,
N0-dialkylthioureas systems. In the present work, we have
synthesized and studied ligands MTCB and PTCB and their
complexes with mercury by FT-IR, NMR and FT-Raman
methods. The crystal structure of complex Hg (MTCB)2 has
been determined by X-ray diffraction technology.
The study of compounds N-benzoyl-N0-alkylthioureas
and N-benzoyl-N0, N0-dialkylthioureas has recently attracted
great interest in view of the potential use of these compounds
as highly selective reagents for the concentration and
separation of metal cations [1–10]. One specific use for
these substances is the coordination with harmful com-
pounds, which can be achieved in the organism by one of
several ligands of adequate structure. This is an important
aspect and in future more attention should be devoted to the
design and synthesis of new agents able to coordinate these
toxic metal ions with a view to obtain complexes that can be
readily eliminated.
Mercury (II) complexes with heterocyclic molecules
which may contain nitrogen, oxygen or sulphur as
endocyclic or a combination of these and an exocyclic
thione (thioketo) group can be used to imitate mercury
cysteine thionato interactions in biosystems [11–13] as well
as to establish the toxicological behavior of mercury
[14,15]. As the continuation of our interest in mercury
complexes, in the present study we have investigated
2. Experiment
*
Corresponding author. Tel.: C86 0512 65125164.
E-mail address: wqzhou@suda.edu.cn (Z. Weiqun).
X-ray diffraction structure determination was carried out
with Rigaku Mercury CCD. Melting points were determined
on a Kofler melting point apparatus and uncorrected.
0022-2860/$ - see front matter q 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.molstruc.2005.03.046

90
Z. Weiqun et al. / Journal of Molecular Structure 749 (2005) 89–95
IR spectra were obtained in KBr discs using a Nicolet
Magna550 spectrometer. NMR spectroscopy was recorded
in CDCl3 at room temperature at 400 MHz on an INOVA
400 instrument. The FT-Raman spectrum was measured
with a SPEX-1377 laser Raman spectrometer at room
temperature. An Ar-ion laser with a wavelength of 514.5 nm
in a backscattering configuration was used to excite the
N-(piperidylthiocarbonyl) benzamide: colorless, Mp:
123–124 8C. Elemental analysis: found (%C, H, N, S):
63.01, 6.22, 11.20, 12.9. Stoichiometric amounts (% C, H, N,
S): 63.13, 6.11, 11.33, 12.96. FTIR (cmK1): 3161.7, 3061.3,
2927.6, 2858.0, 2424.2, 1651.4, 1581.1, 1538.1, 1470.8,
1370.3, 1284.8, 1280.0, 1249.47, 1180.7, 1137.3, 1076.0,
1018.9, 947.4, 908.3, 971.7, 839.0, 794.4, 713.6, 655.9,
616.6, 570.1, 491.1, 448.9, 428.6, 404.0. 1H NMR (CDCl3)
(ppm): 8.524, 7.776 (d), 7.623, 7.489 (d), 3.243 (d), 3.024 (d)
2.043 (q), 1.724 (d). 13C NMR (CDCl3) (ppm): 179.3, 138.5,
132.5, 132.1, 126.1(d), 127.8(d), 43.0(d), 34.3(d), 23.6.
crystals. The spectral resolution was 4.0 cmK1
.
2.1. Synthesis and characterization of the ligands
of N-benzoyl-N0-dialkylthiourea derivatives
N-benzoyl-N0-dialkylthiourea derivatives MTCB and
PTCB were synthesized following the procedure given in
the literature [23]. A freshly prepared acetone solution
of benzoyl isothiocyanic synthesized by condensation of
benzoyl chloride with NH4SCN was added dropwise to
chemical calculated solutions of morpholine or piperine
with stirring. After addition, the mixture was heated under
reflux for 1–2 h and poured onto crushed ice with vigorous
stirring. The isolated solids were filtrated, washed with
water, and dried to yield.
2.2. Synthesis and characterization of the complexes
Hg (MTCB)2 and Hg (PTCB)2
The synthesis of complexes Hg (MTCB)2 and Hg
(PTCB)2 are according to the reference [23]. The pure
1 mmol N-(morpholinothiocarbonyl) benzamide or
N-(piperidylthiocarbonyl) benzamide was added respect-
ively in 100 ml water. 10% NaOH was added dropwise until
the suspension was dissolved. Added respectively
0.05 mmol HgCl2 water solution, maintained stirring 1 h,
the deposition was washed by water separately, and dried.
Hg (MTCB)2: colorless. Elemental analysis: Obs. (%C,
H, N, S): 41.38, 7.82, 4.12, 9.3. Stoichiometric amounts
(%C, H, N, S): 41.23, 8.00, 3.96, 9.2.
N-(morpholinothiocarbonyl) benzamide: colorless, Mp:
131–132 8C. Elemental analysis: found (% C, H, N, S):
57.68, 5.30, 11.14, 12.9. Stoichiometric amounts (%C, H, N,
S): 57.81, 5.26, 11.24, 12.86. FTIR (cmK1): 3236.2,
2963.3, 2924.6, 2847.0, 2448.3, 1670.5, 1530.8, 1453.3,
1418.4, 1353.7, 1276.1, 1193.4, 1141.7, 1111.9, 1060.2,
1034.4, 955.5, 938.8, 843.0, 791.3, 709.8, 658.3,
618.4, 498.7, 462.1, 408.9. 1H NMR (CDCl3) (ppm):
8.439, 7.856 (doublet, d), 7.634, 7.489 (d), 4.253 (d),
3.884 (quadruplet, q), 3.675 (d). 13C NMR (CDCl3) (ppm):
176.4, 164.5, 134.2, 132.2, 126.1 (d), 125.8 (d), 67.8 (d),
50.5 (d).
Hg (PTCB)2: colorless. Elemental analysis: Obs. (%C, H,
N, S): 45.02, 4.28, 8.22, 9.04. Stoichiometric amounts (%C,
H, N, S): 44.92, 4.35, 8.06, 9.2.
2.3. Structure determination of the complex Hg (MTCB)2
The growth of the single crystal of the complex Hg
(MTCB)2 is carried out by slow evaporating solvent toluene.
Fig. 1. ORTEP plot of Hg(MTCB)2, thermal ellipsoids and depicted at 50%.

Z. Weiqun et al. / Journal of Molecular Structure 749 (2005) 89–95
91
A colorless block crystal with approximate dimensions
of 0.18!0.60!0.35 mm3 was mounted on a glass fiber.
All measurements were made on a Rigaku Mercury CCD
area detector with graphite monochromatic Mo-Ka
effects. The crystal structure is of the triclinic, space
˚
ꢀ
˚
group: P1 (#2), aZ10.3621(11) A, bZ11.5738(11) A,
˚
cZ12.7722(7) A,
aZ64.493(8)8,
bZ66.132(8)8,
3
˚
gZ85.811(11)8, VZ1254.7(2) A , ZZ2. F000Z684,
R1(IO3.00s(I))Z0.035, wR2(IO3.00s(I))Z0.097. The
molecular structure by X-ray determination is showed in
Fig. 1. The crystallographic information file is deposited
with the Cambridge Crystallographic Data Center as CCDC
262322, and non-hydrogen atom coordination and thermal
parameters were listed in Table 1, selected bond parameters
are listed in Table 2.
˚
(lZ0.71070 A) radiation. Data were collected by u scan
technique. The data were collected at a temperature of
K80G1 8C to a maximum 2q value of 55.08. A total of 720
oscillation images were collected. A sweep of data was done
using q scans from K80.0 to 100.08 in 0.58 step, at cZ45.08
and fZ0.08. The exposure rate was 6.0 [s/deg.]. The
detector swing angle was 9.978. A second sweep was
performed using scans from K80.0 to 100.08 in 0.58 step, at
cZ45.08 and fZ90.08. The exposure rate was 6.0 [s/deg.].
The detector swing angle was 9.978. The crystal-to-detector
distance was 34.53 mm. Readout was performed in the
0.273 mm pixel mode. The structure was solved by direct
methods and expanded using Fourier techniques ‘SIR97’
[24]. The non-hydrogen atoms were refined anisotropically.
Hydrogen atoms were refined using the riding model. The
data were corrected for Lorentz and polarization
3. Results and discussion
3.1. Structure discussion
The crystal structure of Hg(MTCB)2 is built up of
discrete complex molecules shown in Fig. 1. The charac-
teristic mercury coordination in Hg (MTCB)2 is
diagonal since S1–Hg1–S2 valence angle is almost
1808(S2–Hg–S1Z172.9928), which is in a very good
Table 1
Atomic coordinates and Biso/Beq and occupancy
˚
agreement with Hg–S bond distance of 2.34 A, character-
˚
istic for the sum of covalent radius of Hg (1.30 A for
Atom
x
y
z
Beq
˚
diagonal coordination and covalent radius of S, 1.04 A
´
according to Pauling [30] and Grdenic [31]). The Hg atom is
additionally coordinated by atoms O1 and O3, at distances
Hg(1)
S(1)
K0.00856(2)
K0.07769(13) 0.19251(12) 0.44095(13) 2.03(2)
0.41542(2)
0.32251(2)
1.785(5)
S(2)
0.0318(1)
0.1551(5)
0.2464(4)
0.2034(4)
0.3916(5)
0.1918(5)
0.1447(4)
0.3029(4)
0.2796(4)
0.1847(5)
0.2273(5)
0.2759(5)
0.64049(12) 0.20678(13) 2.19(2)
O(1)
O(2)
O(3)
O(4)
N(1)
N(2)
N(3)
N(4)
C(1)
0.3451(4)
0.0541(4)
0.4319(4)
0.1457(4)
0.6956(4)
0.3679(4)
2.95(9)
2.43(8)
2.48(8)
3.55(10)
2.26(9)
1.70(7)
2.06(8)
1.98(8)
1.90(9)
1.69(9)
1.96(9)
2.55(11)
2.71(11)
2.41(11)
2.23(10)
1.77(9)
2.32(10)
2.37(10)
2.09(9)
2.50(10)
1.83(9)
1.71(9)
2.59(11)
3.04(13)
2.74(12)
2.41(10)
2.11(10)
1.72(9)
2.25(10)
2.92(12)
2.41(10)
3.3(1)
˚
of 2.631 and 2.527 A, which is less than the van der Waals
radii of the corresponding atoms, so the effective
coordinated can be described as 2C2. These contacts are
responsible for the elongation of the Hg–S bond and for the
slight deviation from linearity. In fact, the N1–C8
0.6608(5) K0.2191(4)
0.1650(4)
0.1278(4)
0.6238(4)
0.7025(4)
0.2325(5)
0.1667(5)
0.0459(5)
0.2986(4)
0.5025(4)
0.1893(4)
0.0015(4)
0.1850(5)
0.0995(4)
0.1343(5)
0.0553(5)
˚
(1.304 A), is similar to CaN bond length 1.298 A [4],
˚
Table 2
C(2)
The selected structure parameters of X-ray experimental
C(3)
C(4)
0.3079(6) K0.0138(5)
Bond lengths
(nm)
Bond lengths
˚
(A)
Bond angles (8)
Torsion
angles
C(5)
0.2886(6)
0.2429(6)
0.2137(6)
0.1039(5)
0.2972(5)
0.3194(6)
0.0634(6)
0.0976(6)
0.2701(5)
0.3256(5)
0.3993(6)
0.4433(7)
0.4151(6)
0.3453(5)
0.3018(5)
0.2213(5)
0.4339(5)
0.4627(6)
0.2027(6)
0.2421(7)
0.0432(6) K0.0557(5)
0.1646(5) K0.0935(5)
0.2256(5) K0.0157(5)
C(6)
C(7)
Hg(1)–S(1)
Hg(1)–S(1)
Hg(1)–O(3)
Hg(1)–O(1)
S(1)–C(8)
O(1)–C(1)
O(2)–C(10)
N(1)–C(8)
N(1)–C(1)
N(2)–C(8)
N(2)–C(9)
C(1)–C(2)
C(9)–C(10)
C(11)–C(12)
C(2)–C(3)
C(2)–C(7)
C(3)–C(4)
C(4)–C(5)
C(6)–C(7)
C(5)–C(6)
2.343(1)
2.343(1)
2.526(5)
2.631(5)
1.794(5)
1.243(7)
1.428(7)
1.304(7)
1.350(8)
1.341(8)
1.469(7)
1.499(9)
1.519(8)
1.508(8)
1.392(8)
1.396(7)
1.38(1)
S(1)–Hg(1)–S(2)
S(1)–Hg(1)–O(3)
S(1)–Hg(1)–O(1)
O(1)–Hg(1)–O(3)
C(8)–S(1)–Hg (1)
C(1)–O(1)–Hg (1)
C(10)–O(2)–C(12)
C(8)–N(1)–C(1)
C(8)–N(2)–C(9)
C(8)–N(2)–C(11)
C(9)–N(2)–C(11)
S(1)–C(8)–N(1)
S(1)–C(8)–N(2)
N(1)–C(8)–N(2)
C(2)–C(1)–O(1)
C(2)–C(1)–N(1)
O(1)–C(1)–N(1)
C(10)–C(9)–N(2)
O(2)–C(10)–C(9)
C(11)–C(12)–O(2)
173.00(5)
99.29(9)
81.94(9)
88.7(2)
C(8)
0.1630(4)
0.1242(6)
0.0288(6)
0.1412(5)
0.0424(6)
0.5413(5)
0.5850(5)
0.7080(6)
0.7500(6)
0.6691(6)
0.5472(6)
0.5048(5)
0.6501(4)
0.4069(5)
0.4721(5)
0.5884(5)
0.6206(5)
0.7271(5)
0.3132(5)
0.3818(4)
0.3240(5)
0.3924(6)
0.5185(5)
0.5758(5)
0.5077(5)
0.1296(4)
C(9)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
C(19)
C(20)
C(21)
C(22)
C(23)
C(24)
91.1(1)
115.8(3)
108.6(5)
126.1(5)
117.9(4)
124.3(4)
113.4(5)
123.0(1)
116.1(2)
119.9(4)
119.6(5)
115.4(5)
124.7(3)
110.4(4)
112.2(1)
111.5(4)
0.7107(6) K0.0692(5)
0.6275(6) K0.1376(5)
0.7334(5) K0.0802(5)
0.6475(7) K0.1477(6)
1.391(8)
1.38(1)
BeqZ8/3p2(U11(aa*)2CU22(bb*)2CU33(cc*)2C2U12(aa*bb*) cos gC
2U13(aa*cc*) cos bC2U23(bb*cc*) cos a.
1.37(1)

92
Z. Weiqun et al. / Journal of Molecular Structure 749 (2005) 89–95
˚
N1–C1 (1.350 A) has values between C–N single bond and
˚
double bonds. The bonds S1–C8 (1.794 A), is longer than
There is a weakly p–p interaction between two phenyl
˚
rings. The distance between C15 and C17(A) is 3.419 A, the
˚
double bonds (1.63 A), so it must derive from the electron
de-localization along the N2–C8–N1–C1 fragment.
˚
distance C16–C16(A), 3.392 A.
˚
Whereas, the bond O1–C1 (1.244 A), is close to CaO
3.2. FT-IR and FT-Raman analysis
double bonds. These bond lengths are similar to those
observed for related complexes and thiourea derivatives
[25–27]. No significantly difference exists for morpholine
ring in the crystal comparing with 4,40-carbonyl-di-morpho-
line[28]. The intramolecular hydrogen bonding between NH
and benzoyl oxygen is inexistence due to de-protonated
of the N(2) nitrogen atom. That would be responsible for
the conformational dispositions were seen in this compound
and it must derive from the electron delocalization along the
C(Ph)–N–C(S)–N fragment. The intramolecular hydrogen
bonding are found, C9–H/N1, nonbonding distance,
The FT-IR spectra of two compounds, MTCB and PTCB
together with their two complexes are shown in Fig. 3. The
CaS and CaO stretch of two complexes shifted to lower
value than pure their ligands due to its coordinate interaction
with Hg2C. In addition, this interaction is also evident by
a shift in the N–C–N stretch of thiourea to higher value in
the complexes compared to the ligands. CaS and CaO
coordination to mercury ion enhances the resonance
delocalization of nitrogen atom lone pair electrons, thus
providing more double bond character for N–C–N, hence
both symmetric and asymmetric N–C–N stretching is
shifted to higher values. In pure ligands, CaS and CaO
are bonded to NH, whereas in the complexes are bonded to
Hg2C and therefore increasing C–S and C–O bonding
length, bonding vibrational mode are also shifted to lower
values (Fig. 3).
˚
2.703 A, !C9HN1, 102.88 and C3H/O1, nonbonding
˚
distance, 2.802 A, !C3HO1, 99.08.
A interaction is found between the mercury ion and the
phenyl ring of MTCB, and the distances are Hg(1)–C(20A),
˚
˚
3.263 A, Hg(1)–C(21A), 3.282 A, shown in Fig. 2. It is
attributed empty out-nucleus atomic orbits of metal ion and
p electrons of phenyl ring, which formed the interaction
of donor (p electrons)–acceptor (Hg2C). A intermolecular
hydrogen boned interaction is C(11) H(12).O(2),
As all thiosemicarbazones, our ligands can exhibit
thione–thiol tautomerism, since it contains a thioamide
–NH–CaS functional group. There is an IR band at
2400–2500 cmK1 in the spectrum of the free ligands, and
these indicate the existence of S–H group in the free ligands.
˚
the distance of C(11) H(12).O(2) is 3.206 A,
!C(11)H(12)O(2) is 149.88.
Fig. 2. The interactions of the mercury cations and the phenyl rings.

Z. Weiqun et al. / Journal of Molecular Structure 749 (2005) 89–95
93
Fig. 3. The FT-IR spectra of MTCB and PTCB and their complexes with mercury cation(II).
However, there are bands in the regions of 843.0,
838.98 cmK1 and 3241.2, 3161.7 cmK1, characteristic of
n(CaS) and n(N–H), respectively, indicating that the ligand
remains as the thione tautomer.
at about 1530 cmK1 in free ligand also discovered in the
complex is attributed to d(Ph–H).
In addition, this interaction is also evident of the N–C–N
stretching vibrations of thiourea occur at 1443 and
1406 cmK1 in ligands thioureas and shift to about
1500 cmK1 in the complexes, these frequencies is strongly
increased because of the greater double bond character
of C–N bond. As expected, a appears at 1500 cmK1 due to
N–C–N asymmetric stretching vibrations. The weak bands
at 669 cmK1 are attributed to CaS symmetric stretching
vibration. Some of the CaS vibration bands overlap
with N–C–N. The bands 1583.2,15, 1530.8, 1581.14,
1538.06 cmK1 found in the ligands are attributed to
d(Ph–H) shift to 1517.7 and 1511.7 cmK1 in their mercury
complexes. The shown thionyl asymmetric stretching
vibration band at about 1260 cmK1 for ligands shifts to
1220 cmK1 for the complexes, as resulting of coordination
to metal mercury. Both ligands and complexes, the bands
The experimental band about 3200 cmK1 in free ligands,
corresponding to the stretching n(NH) vibrations of the
hydrogen bond NH groups is disappeared in the complex
along with the disappearance of the N–H bond. The peak at
3048.2 cmK1 is assigned to n(Ph–H), and this absorb peak
is covered with wide absorb bands at the 3236.2 cmK1 in the
ligand MTCB. The bands at 2936.18, 2847.80 cmK1 are
assigned to n(CH2) and appeared almost at the same wave
number in the complex. The bands at 1667.7 cmK1 in the
free ligands are disappeared in the corresponding com-
plexes. The substituted bands about at 1600 cmK1 are
found. In the laser Raman spectra, these bands appear at the
same frequency with very strong intensity. The appearance
of the bands are attributed to CaN double bonded. The band

94
Z. Weiqun et al. / Journal of Molecular Structure 749 (2005) 89–95
Fig. 4. FT-Raman spectra of Hg(MTCB)2.
Fig. 5. FT-Raman spectra of Hg(PTCB)2.
at about 1420 cmK1 would be attributed to nCH2, and the
band about 1100 cmK1 would be attributed to nC–O.
The laser Raman spectra recorded for both complexes to
compliment the FTIR results are shown in Figs. 4 and 5. The
presence of all functional groups is confirmed from FTIR.
The bands about 290–300 cmK1 of the complexes are
assigned to Hg–S stretching vibrations. The peaks around
370 cmK1 absorb peaks are assigned to Hg–O stretching
vibrations. It is supported by the work of Bertin [29] and is
in a very good agreement with experimental X-ray
diffraction results.
and the Hg2C cations is weaker than between the
sulfur atoms and the Hg2C. A weaken interaction donor(p
electrons)–acceptor(Hg2C) is found between the mercury
ion and the phenyl ring of ligand MTCB. The results of FT-
IR, FT-Raman and NMR experiments are agreement with
the X-ray diffraction. The ligands thioureas can be
examined thione–thiol tautomerism by FT-IR method,
since it contains a thioamide –NH–CaS functional group.
References
4. Conclusion
[1] C.C. Chambers, E.F. Archibong, A. Jabalameli, R.H. Sullivan,
D.J. Giesen, C.J. Cramer, D.G. Truhlar, J. Mol. Struct. (Theochem)
425 (1998) 61.
According to the X-ray data of the structure of
Hg(MTCB)2, the intramolecular hydrogen bonding between
NH and benzoyl oxygen is inexistence due to no hydrogen
atom bonded to nitrogen atom. All of C–N bonds lengths in
the complex crystal are shorter than the normal C–N.
The coordination interaction between the oxygen atoms
[2] Schroeder, Chem. Rev. 55 (1955) 181.
[3] O.F. Huebhr, J.L. Marsh, R.H. Mizzoni, R.P. Mull, D.C. Schroeder,
H.A. Troxell, C.R. Scholz, J. Am. Chem. Soc. 75 (1953) 2274.
[4] R.P. Rao, Indian J. Appl. Chem. 23 (1960) 110.
[5] V.K. Madan, A.D. Taneja, Indian Chem. Soc. 68 (1991) 471.

Z. Weiqun et al. / Journal of Molecular Structure 749 (2005) 89–95
95
[6] E. Rodriguez-Fernandez, E. Garcia, M.R. Hermosa, A. Jimenez-
Sanchez, M.M. Sanchez, E. Monte, J.J. Criado, J. Inorg. Biochem. 75
(1999) 181.
[20] C.S. Salteris, I.D. Kostas, M. Micha-Screttas, B.R. Steele,
G.A. Heropoulos, C.G. Screttas, A. Terzis, J. Organomet. Chem. 590
(1999) 63.
[7] L. Beyer, J.J. Garcia, E. Garcia, F. Lessmann, M. Medarde, R. Richter,
E. Rodriguez, Tetrahedron 52 (1996) 6233.
[21] E.S. Raper, J.R. Creighton, N.A. Bell, W. Clegg, L. Cucurull-
Sanchez, Inorg. Chim. Acta 277 (1998) 14.
[8] I. Dechamps-Olivier, E. Guillon, A. Mohamadou, J.P. barbbier,
Pelyhedron 15 (1996) 3617.
[22] Z. Popovic, D. Matkovic-Calogovic, J. Hasic, D. Vikic-Topic, Inorg.
Chim. Acta 285 (1999).
[9] R.D. Campo, J.J. Crriado, E. Garcia, M.R. Hermosa, A.J. Sanchez,
J.L. Manzano, E. Monte, E. Rodriguez-Fernandez, F. Sanz, J. Inorg.
Biochem. 89 (2002) 74.
[23] W. Zhou, L. Zhu, Y. Zhang, Z. Yu, L. Lu, X. Yang, Vib. Spectrosc. 36
(2004) 73.
[24] SIR97:A. Altomare, M. Burla, M. Camalli, G. Cascarano,
C. Giacovazzo, A. Guagliardi, A. Moliterni, G. Polidori, R. Spagna,
J. Appl. Crystallogr. 32 (1999) 115.
[10] M. Dominguez, E. Antico, L. Beyer, A. Aghirre, S. Garcia-Granda,
V. Salvado, Polyhedron 21 (2002) 1429.
[11] R.W. Pickersgill, P. Rizkallah, Acta Crystallogr. B 47 (1991) 766.
[12] R.A. Steele, S.J. Opella, Biochemistry 36 (1997) 6885.
[13] I.G. Dance, Polyhedron 5 (1986) 1037.
[25] E. Rodriguez-Fernandez, E. Garcia, M.R. Hermosa, A. Jimenez-
Sanchez, M.M. Sanchez, E. Monte, J.J. Criado, J. Inorg. Biochem. 75
(1999) 181.
[14] B.V. Cheesman, A.P. Arnold, D.Z. Rabenstein, J. Am. Chem. Soc.
110 (1988) 6359.
[26] K.R. Koch, S. Bourne, J. Mol. Struct. 441 (1) (1998) 11.
[27] W.Q. Zhou, K.Sh. Leng, Y. Zhang, L.D. Lu, J. Mol. Struc. 657 (2003)
215.
[15] K.B. Nielsen, C.L. Atkin, D.R. Winge, J. Biol. Chem. 260 (1985) 5342.
[16] W. Zhou, L. Zhu, Y. Zhang, Z. Yu, L. Lu, X. Yang, Vib. Spectrosc. 36
(2004) 73.
[28] W.Q. Zhou, L.M. Zhu, Zh.B. Cao, Y. Zhang, J. Mol. Struct. 655
(2003) 405.
[17] A.R. Lennie, J.M. Charnock, R.A.D. Pattrick, Chem. Geol. 199 (2003)
199.
[29] E.P. Bertin, I. Nakagawa, S. Mizushima, Jivi Qvaglian, J. Am. Chem.
Soc. 80 (1958) 525.
[18] G. Mugesh, Harkesh B. Singh, Ray J. Butcher, Eur. J. Inorg. Chem.
1999; 1229.
´ ´ ´
[19] Z. Popovic, D. Matkovic-Calogovica, Z. Soldina, G. Pavlovica,
[30] L. Pauling, The Nature of the Chemical Bond, third ed., Cornell
University Press, Ithaca, 1960.
´
[31] D. Grdenic, Q. Rev. Chem. Soc. 19 (1965) 303.
´ ´ ´
N. Davidovic, D. Vikic-Topic, Inorg. Chim. Acta 294 (1999) 35.