One-pot preparation, spectroscopic and structural characterization of mercury(II) complexes of bulky diimines with halides and pseudohalides

Article abstract of DOI:10.1002/zaac.200800220

The preparation and characterization of two novel HgCl₂ and Hg(SCN)₂ complexes with bis[N-(2-tert-butylphenyl)imine]acenaphthene is here described. One-pot reaction techniques were used, leading to high yields of 75 % and 81 %, respectively. The complexes were characterized by microanalysis, i.r. and ₁HNMR spectroscopy, and by single crystal X-ray diffraction. The structures of the complexes present similar characteristics, the most outstanding being the formation of dimers via intermolecular interaction. Whereas the HgCl₂ complex shows a unidimensional network due to strong π-π interactions, its Hg(SCN) ₂ counterpart displays a supramolecular arrangement resulting from non classical hydrogen bond formation.

Full text of DOI:10.1002/zaac.200800220

DOI: 10.1002/zaac.200800220
One-pot Preparation, Spectroscopic and Structural Characterization of
Mercury(II) Complexes of Bulky Diimines with Halides and Pseudohalides
a
a,
a
a,†
˜
Leonardo C. Ferreira , Carlos A. L. Filgueiras *, Lorenzo C. Visentin , Jairo Bordinhao
and Manfredo Hörnerb
,
a
´
Rio de Janeiro / Brazil, Instituto de Quımica, Universidade Federal do Rio de Janeiro
b
´
Santa Maria / Brazil, Departamento de Quımica, Universidade Federal de Santa Maria
Received April 30th, 2008; accepted May 27th, 2008.
Abstract. The preparation and characterization of two novel HgCl2
and Hg(SCN)2 complexes with bis[N-(2-tert-butylphenyl)imine]a-
cenaphthene is here described. One-pot reaction techniques were
used, leading to high yields of 75 % and 81 %, respectively. The
complexes were characterized by microanalysis, i.r. and 1HNMR
spectroscopy, and by single crystal X-ray diffraction. The structures
of the complexes present similar characteristics, the most outstand-
ing being the formation of dimers via intermolecular interaction.
Whereas the HgCl2 complex shows a unidimensional network due
to strong πϪπ interactions, its Hg(SCN)2 counterpart displays a
supramolecular arrangement resulting from non classical hydrogen
bond formation.
Keywords: Mercury; α-Diimines; Crystal structures; π-π Interac-
tions; Hydrogen bonds
Introduction
of an aniline, catalyzed by a Lewis acid such as formic acid.
Several solvents are used, the most common being MeOH
and HCO2H. The reactions lead to high yields and the
products can be characterized by C,H,N analysis, i.r. and
1H and 13CNMR, as well as X-ray diffraction.
Coordination chemistry involving ligands with 1,4-diazabu-
tadiene groups has attracted much attention in recent years.
One of the main reasons for this interest is related to their
application as pre-catalysts in olefin polymerization, after
this behavior was demonstrated in 1990 by Brookhart and
collaborators [1]. The first complexes to be used were cat-
ionic α-diimine NiII species, which are effective in ethylene
polymerization, as well as in homo- and copolymerization
of polar monomers. In 1995 PdII complexes with bulky di-
imines were shown to be more active than with smaller li-
gands [2]. In view of the great success earned by NiII and
PdII diimine complexes, several other metal ions have also
been studied in this respect. Ions such as ZnII, CuII and
CoII, for instance, were proven to be active in polymeriz-
ation processes [3].
The choice of the diimine is doubtlessly one of the most
important items for the catalysis to proceed well. This is
linked directly to the substituents on the aromatic rings pre-
sent in the diimine. The preparation of the ligands is a well-
known procedure. Routes for their synthesis have been de-
veloped by Dieck and Dietrich [4], Fukuda et al. [5] and
Elsevier et al. [6]. The most widely used method involves
the reaction of 1 equivalent of a dicetone with 2 equivalents
In most cases the α-diimines are first prepared, charac-
terized and then put to react with the chosen metal salt. It
is, however, possible to obtain the final complex in a single
stage, by means of the so-called “one-pot reaction“. In
2002, Rausch et al. [7] succeeded in establishing this syn-
thetic route. 1 equivalent of both acenaphthenequinone and
NiBr2 were reacted with 2 equivalents of 2-tert-butylaniline,
in the presence of HOAc as solvent and catalyst. The prod-
uct was isolated and characterized, leading to a 77 % yield
of the desired complex, establishing the route as a successful
one. After a literature search, only one paper was found
describing the preparation and characterization of a HgII
complex with an α-diimine containing a acenaphthene
ring [8].
The present paper describes the synthesis and spectro-
scopic as well as structural characterization of two novel
HgII complexes containing bis[N-(2-tert-butylphenyl)-
imine]acenaphthene. The structure of the ligand has already
been reported by us [9].
Results and Discussion
The i.r. spectra of 1 and 2 show the appearance of the
characteristic diimine CN stretching vibrations [10]. When
Cl is replaced by SCN in the complex, the diimine vi-
brations occur at 1666(νas) and 1626(νs) cmϪ1, respectively.
Comparing these values with those of the free ligand, which
are observed at 1664(νas) and 1640(νs) cmϪ1, respectively,
* Prof. C. A. L. Filgueiras
Instituto de Quımica
Universidade Federal do Rio de Janeiro
C.P. 68563
21945-970 Rio de Janeiro / Brazil
Tel.: 55-21-2562-7812; fax: 55-21-2562-7559
E-mail address: calf@iq.ufrj.br
´
1896
© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2008, 634, 1896Ϫ1900

Mercury(II) Complexes of Bulky Diimines with Halides and Pseudohalides
˚
Table 1 Crystal data and structure refinement for 1 and 2
Table 2 Important bond lengths/A and bond angles/° for 1 and 2
Empirical formula
Formula weight
T /K
Radiation, λ /A
Crystal System, space group
Unit cell dimensions, a, b, c /A a ϭ 11.5395(3)
b ϭ 12.4890(3)
C32H32Cl2N2Hg(1)
716.12
295(2)
C32H32N4S2Hg(2)
761.35
295(2)
Complex 1
Complex 2
Hg1-N1
Hg1-N2
Hg1-Cl1
Hg1-Cl2
Hg1-S1
Hg1-S2
C33-N3
C34-N4
C1-N1
2.510(5)
2.594(5)
2.399(2)
2.314(2)
Ϫ
Ϫ
Ϫ
Ϫ
2.396(3)
2.498(3)
Ϫ
˚
0.71073
triclinic, P1
0.71073
¯
monoclinic, P21/c
a ϭ 11.3839(2)
b ϭ 22.5820(4)
c ϭ 12.4162(2)
β ϭ 97.0090(10)°
˚
Ϫ
2.533(9)
2.412(12)
1.152(5)
1.150(7)
1.273(4)
1.264(4)
1.522(4)
c ϭ 12.7860(3)
Ͱ ϭ 65.5190(10)°
β ϭ 68.8130(10)°
γ ϭ 83.0100(10)°
1.261(8)
1.275(8)
1.519(10)
3
˚
Volume /A
1522.81(7)
3167.99(9)
4, 1.596
5.019
C2-N2
C1-C2
Z, Calculated density /g.cmϪ3 2, 1.522
Absorption coefficient /mmϪ1 5.117
F(000)
704
1504
N1-C13
N2-C19
1.448(9)
1.417(9)
66.91(18)
111.8(5)
123.(4)
119.2(6)
141.93(8)
89.42(14)
128.05(15)
Ϫ
1.453(4)
1.447(4)
69.89(8)
114.1(2)
125.50(19)
119.6(3)
Ϫ
Crystal size / mm
Theta range /°
Index range
0.056 x 0.117 x 0.276 0.299 x 0.240 x 0.181
3.06 to 25.50°
Ϫ13 Յ h Յ 13,
Ϫ15 Յ k Յ 14,
Ϫ15 Յ l Յ 14
25655
5811 [R(int) ϭ 0.0519] 5888 [R(int) ϭ 0.0248]
99.7 %
2.55 to 25.50°
Ϫ13 Յ h Յ 13,
Ϫ27 Յ k Յ 24,
Ϫ15 Յ l Յ 14
30862
N1-Hg1-N2
C1-N1-Hg1
C13-N1-Hg1
C2-N2-C19
Cl1-Hg1-Cl2
N1-Hg1-Cl1
N1-Hg1-Cl2
S1-Hg1-S2
S1-Hg1-N1
S1-Hg1-N2
S1-C33-N3
S2-C34-N4
Reflections collected
Independent reflections
Completeness to theta max.
Max. and min. transmission
Refinement method
Ϫ
Ϫ
99.9 %
0.7626 and 0.3325
Full-matrix
0.3143 and 0.4652
Full-matrix
122.45(5)
101.63(7)
93.44(6)
178.5(4)
176.6(5)
Ϫ
Ϫ
Ϫ
Ϫ
least-squares on F2
least-squares on F2
5888/0/322
Data / restraints / parameters 5811/0/334
Goodness-of-fit on F2
0.951
1.066
Final R indices [I>2sigma(I)] R1 ϭ 0.0348
wR2 ϭ 0.0809
R indices (all data)
R1 ϭ 0.0247
wR2 ϭ 0.0621
R1 ϭ 0.0316
wR2 ϭ 0.0640
0.965 and Ϫ0.724
R1 ϭ 0.0544,
wR2 ϭ 0.0850
0.406 and Ϫ0.553
shared by both complexes is the relative position of the sub-
stituents in the aromatic rings; in both the tert-butyl groups
are cis, preserving the same configuration already seen in
the crystal structure of the free ligand [9]. The crystal struc-
tures of 1 and 2 are shown in Figures 1 and 2, respectively.
Largest diff. peak and hole
Ϫ
Ϫ3
˚
(e .A
)
one sees that the symmetric stretch is displaced in both
complexes, which is an indication of metal complexation at
the diimine nitrogens atoms. Thiocyanate absorptions are
also seen in the high frequency spectrum of 2, at 2137(νas)
and 2062(νs) cmϪ1, respectively. Whereas the 2062 cmϪ1 ab-
sorption is invariant in both the free and in the complexed
ligand, the absorption at 2137 cmϪ1 is indicative of bonding
to the metal via the S atom, which increases the CN bond
order. Indeed, the CN absorption in ionic thiocyanate, such
as in Kϩ[NCS]Ϫ, occurs at 2032 cmϪ1 [11]. Considering
that this ionic compound has an average CN bond order
between 3 and 2, due to resonance, an increase in the ab-
sorption value means that the CN bond force constant and
hence the CN bond order of the complex is greater than
that of the free ligand, i.e., the bond to the metal is likely
to occur via the S atom. This spectral evidence is confirmed
by the X-ray results. All other absorptions are listed in the
experimental section.
Crystal data, details of data collection and structure re-
finement are listed in Table 1. Selected bond distances and
angles of the complexes 1 and 2 are listed in Table 2.
In the crystal structure of 1, the mercury atom is coordi-
nated to two chloride ions and to the α-diimine in a biden-
tate manner. Thus, the mercury atom in 1 has a coordi-
nation number of four, with a distorted tetrahedral
surrounding. The crystal structure of 2 shows the same
characteristics of 1, with the difference of having two thio-
cyanate ligands replacing the chlorides. Another feature
Figure 1 ORTEP [13] projection of complex bis[N-(2-t-butylphen-
yl)imine]acenaphthenedichloromercury(II) (1). Thermal ellipsoids
in the level of 40 % of the probability. H atoms were omitted for
better visualization.
˚
The Hg1-N1 and Hg1-N2 bond lengths of 1, 2.510(5) A
˚
and 2.594(5) A, respectively, are longer than the similar
˚
˚
bond lengths of 2, 2.396(3) A and 2.498(3) A, respectively.
This difference can be assigned to a stronger coordination
of the metal to the α-diimine in 2. On the other hand, the
N1-Hg1-N2 bite angles of 66.91(18)° and 69.89(8)°, for 1
and 2, respectively, show no significant difference.
Z. Anorg. Allg. Chem. 2008, 1896Ϫ1900
© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wiley-vch.de
1897

L. C. Ferreira, C. A. L. Filgueiras, L. C. Visentin, J. Bordinha˜o, M. Hörner
Figure 3 Dimeric structure [13] of 1. Symmetry code for equiva-
lent atoms, (Ј) ϭ Ϫx, 1Ϫy, 1Ϫz. H atoms were omitted for better
visualization.
Figure 2 ORTEP [139 projection of complex bis[N-(2-t-butyl-
phenyl)imine]acenaphthenebis(thiocyanate)mercury(II) (2). Ther-
mal ellipsoids in the level of 40 % of the probability. H atoms were
omitted for better visualization.
˚
˚
The bond lengths in 1, 2.399(2) A and 2.324(2) A for
Hg1-Cl1 and Hg1-Cl2, respectively, agree well with values
found in the literature [8]. The bond lengths C-S and C-N
of the thiocyanate group in 2 are also in agreement with the
literature [12]. The bond lengths C33-N3 and C34-N4, of
˚
˚
1.152(5) A and 1.150(7) A, respectively, correspond to
lengths more akin to a triple bond, which explains the
higher CN stretching frequency observed in the i.r. spec-
trum, as discussed above. Selected geometric parameters for
1 and 2 are collected in Table 2 and conform to expected
values.
Figure 4 Dimeric structure [13] of 2. Symmetry code for equiva-
lent atoms, (Ј) ϭ Ϫx, 1Ϫy, 1Ϫz. H atoms were omitted for better
visualization.
The complexes form centrosymmetric dimers held to-
gether by weak Hg-Cl and Hg-S bonds, which can be vis-
ualized in Figures 3 and 4. In 1 the dimeric structure is
built by the interaction of the Hg1 mercury atom of the
asymmetric unit with the Cl1Ј chloride ion of a neighbor
molecule. Likewise, the Hg1Ј atom interacts with the Cl1
chloride ion of the asymmetric unit. The two Hg-Cl dis-
˚
(r.m.s ϭ 0.0086 A) and N1-Hg1-N2. In 2 this deviation is
15.94(1)°, involving the homologous fragments (r.m.s ϭ
0.0071 A); this five-membered ring is thus more staggered
in 1 than in 2. Nevertheless, both angles are relatively high,
and can be attributed to the presence of tert-butyl groups
on the aromatic rings and to the intermolecular interactions
in the dimeric structures.
˚
˚
tances are both 3.104(2) A. It is noteworthy that the sum of
the covalent radii of the atoms involved is lower than the
sum of the van der Waals radii. [symmetry code (Ј) ϭ Ϫx,
1Ϫy, 1Ϫz]
Analysis of the supramolecular structure of 1 shows that
a one-dimensional network is built along the b-axis as a
consequence of the packing of the molecules by means of a
stacking of the acenaphthene rings. The distance of the
π-π interactions is 3.671(1) A, in agreement with the
literature [14]. Figure 5 shows the arrangement along the b
crystallographic axis.
The observed interactions for 2 also led to a dimeric
structure with an inversion center, as shown in Figure 4.
The structure confirms that the metal-ligand interaction
takes place via the sulfur atoms, with an observed Hg-S
˚
˚
distance of 3.144(2) A, showing again the high affinity be-
In 2, the supramolecular arrangement shows that the
crystal packing is achieved by non classical H-bonding [15].
These interactions were calculated using the Platon pro-
gram [16] having C22 in the asymmetric unit as the H do-
nor, and N4Љ in a neighboring molecule as the H acceptor.
tween mercury and sulfur, in agreement with the hard-soft
acid-base concept.
Another feature shared by the structures of both 1 and 2
is a staggered Hg-containing five-membered ring in which
there is a deviation from planarity. In 1 the dihedral angle
amounts to 27.84(3)° between the fragments N1-C1-C2-N2
˚
The C22···N4Љ distance is 3.457(2) A, whereas the
˚
N4Љ···H22 distance is 2.579(2) A. The C22-H22···N4Љ angle
1898
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© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2008, 1896Ϫ1900

Mercury(II) Complexes of Bulky Diimines with Halides and Pseudohalides
Experimental Section
Melting points were determined, without correction, from a Quimi
Q-40M apparatus. Elemental analyses were obtained from a 2400
Perkin-Elmer instrument, using a PE AD-4 balance. I.R. spectra
were collected from a Magna-FTIR Nicolet spectrometer, and
1HNMR spectra were run at room temperature using a 200 MHz
Bruker instrument.
X-ray diffraction data were collected at 295 K from a Bruker AP-
EXII-CCD [17] diffractometer with graphite monochromatized Mo
Kα radiation. Cell parameters of complexes 1 and 2 were obtained
and refined using the SAINT [17] program. Absorption correction
was made with the SADABS [17] program. Data collection analysis
¯
revealed for 1 and 2 a triclinic P1 and a monoclinic P21/c space
group, respectively. The structures were solved by Direct Methods
using the SHELXS-97 [18] program. Atom positions were refined
using the SHELXL-97 [19] program with anisotropic displacement
parameters for all non-H atoms. H atoms were included in idealized
calculated positions and refined riding on their respective C atoms.
Aromatic carbons were refined with Uiso(H) ϭ 1.2 Ueq Csp2 and
tert-butyl group with Uiso(H) ϭ 1.5 Ueq Csp3. X-ray data are listed
in Table 1. The solution and refinement of 1 suggested the presence
of two markedly disordered water molecules as crystallization sol-
vates. The hydrogen atom coordinates corresponding to those water
molecules could not be localized experimentally in the Fourier map.
In view of this we opted for utilizing the SQUEEZE [20] tool con-
tained in the WinGX [20] package, in order to exclude any elec-
tronic density contributions relative to the disordered water mol-
ecules. This procedure is in accordance with the elemental analysis
of the complex, confirming a species free from any cristallization
solvate. This is validated insofar as the water molecules do not
contribute to the supramolecular arrangement under discussion.
The C30, C31 and C32 atoms exhibit disorder effects, which were
shown as a result of the anisotropic refinement. Their Ueq values
are C30, 92(2); C31, 107(3); C32, 94(2), respectively.
Figure 5 Packing [13] of 1 along the b axis. Symmetry for equiva-
lent atoms (Ј) ϭ Ϫx, 1Ϫy, 1Ϫz. H atoms were omitted for better
visualization.
is 156.72(1)°. When a dimer occurs, this intermolecular in-
teraction can be generated by symmetry along both the b
as well as the c crystallographic axis, as shown in Figure 6.
[Symmetry code (Љ) ϭ Ϫ0.5Ϫx, 0.5ϩy, 2Ϫz]
Thus the dimer will present a total of 4 interactions, all
of them with the same structural parameters.
CCDC 670143 & 670144 contains the supplementary crystallo-
graphic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data request/cif.
Preparation of bis[N-(2-t-butylphenyl)imine]acenaph-
thenedichloromercury(II), (1) and bis[N-(2-t-butyl-
phenyl)imine]acenaphthenebis(thiocyanate)mercury(II),
(2)
Figure 6 Packing [13] of 2 along the b and c axis. Symmetry code
for non classical hydrogen bonds, (Љ) ϭ Ϫ0.5Ϫx, 0.5ϩy, 2Ϫz. Non
essential H atoms were omitted for better visualization.
The syntheses of both complexes were carried out using the tech-
nique known as “one pot reaction” [7]. However, in the cases of
complexes (1) and (2) the preparations were modified in relation to
those in the literature, according to which all materials are mixed
together at once in the reaction flask. In our case, the organic start-
ing materials (acenaphthenequinone, 2-t-butylaniline and HOAc as
catalyst) were initially dissolved in MeOH, and only after some
time the metal salt was added, as described below. Scheme 1 shows
the corresponding equation.
The set of data shown is an evidence of how the one
pot reaction technique was essential in order to obtain the
complexes described in this work, and led to good chemical
yields. An analysis of the i.r. spectra gave a good indication
of this success and of the types of bonding in the complexes,
from the observation of the appearance of CN imine
stretching modes and from their frequencies. Structural
analysis by X-ray diffraction led to the establishment of
their crystal structures as well as to the supramolecular ar-
rangement formed by intermolecular interactions due to π-
π interactions and non classical H-bonding, respectively.
0.547 g (3 mmol) of acenaphthenequinone and 0.935 mL (6 mmol)
of 2-t-butylaniline were added to a 100 mL round bottom flask
containing 30 mL of MeOH and 5 drops of glacial HOAc. The
flask was connected to a Liebig condenser and heated under stir-
ring. The temperature was kept 20 °C above the boiling point of
the solvent. The color of the mixture changed from yellow to dark
Z. Anorg. Allg. Chem. 2008, 1896Ϫ1900
© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wiley-vch.de
1899

L. C. Ferreira, C. A. L. Filgueiras, L. C. Visentin, J. Bordinha˜o, M. Hörner
Acknowledgements. The authors are grateful to their sponsors,
CNPq and CAPES.
References
[1] M. Brookhart, A. F. Volpe, D. M. Lincoln, I. T. Hovarth, J.
M. Millar, J. Am. Chem. Soc. 1990, 112, 5634.
[2] F. C. Rix, M. Brookhart, J. Am. Chem. Soc. 1995, 117,
1137Ϫ1138.
[3] M. J. Tanner, M. Brookhart, J. M. DeSimone, J. Am. Chem.
Soc. 1997, 119, 7617Ϫ7618.
Scheme 1 Equation for the preparation of 1 and 2.
[4] H. T. Dieck, J. Dietrich, Chem. Ber. 1984, 117, 694.
[5] A. Paulovicova, U. El-Ayaan, K. Shibayama, T. Morita, Y.
Fukuda, Eur. J. Inorg. Chem. 2001, 10, 2641.
[6] R. Van Asselt, C. J. Elsevier, W. J. J. Smeets, A. L. Spek, R.
Benedix, Rec. Trav. Chim. Pays-Bas 1994, 113, 88.
[7] M. D. Rausch, J. C. W. Chien, J. S. Wood, R. J. Maldanis, J.
Organomet. Chem. 2002, 645, 158Ϫ167.
[8] U. El-Ayaan, Monatsh. Chem. 2004, 135, 919Ϫ925.
[9] L. C. Ferreira, C. A. L. Filgueiras, M. Hörner, L. C. Visentin,
J. Bordinha˜o, Acta Crystallogr. 2007, E63, o3427.
[10] John Dyer, Applications of absortion spectroscopy of organic
compounds, 3rd ed., Ed. Edgard Blücher, 1969, pps 36Ϫ41.
[11] K. Nakamoto, Infrared and Raman Spectra of Inorganic and
Coordination Compounds, 3rd ed., Ed. Wiley and Sons, 1963,
pps 270Ϫ271.
red. After 1h30m, heating was interrupted and the mixture cooled
to room temperature. At this point 3 mmol of the HgII salt was
added (chloride or thiocyanate, respectively) and an orange precipi-
tate was immediately formed. The mixture was then kept under
reflux for 2 more hours. The solid was filtered off and washed with
25 mL of cold MeOH. It was dried in vacuo and weighed, giving
1.61 g (75 %) in the case of 1 and 1.76 g (81 %) in the case of 2.
Both solids were recrystallized from CHCl3, and after a few days
bright orange crystals formed. These were used in m.p. determi-
1
nations, elemental analyses, i.r. and HNMR spectroscopy, and X
ray crystallography.
Properties of 1. Yield, 75 %; m.p. 264Ϫ266 °C; C,H,N analysis:
calcd. for 715.65 gmolϪ1, C, 53.7; H, 4.47; N, 3.91 %; found, C,
53.4; H, 4.2; N, 3.8 %.
[12] R. Kapoor, A. Kataria, A. Pathak, Polyhedron 2005, 24,
1221Ϫ1231.
[13] L. J. Farrugia, ORTEP-3 for Windows, J. Appl. Cryst. 1997,
30, 565.
IR spectroscopy (CsI pellet and nujol film between polyethylene sheets),
cmϪ1: 3097m, 3057m, 2992s, 2960s, 2098m, 2868m, 1667m, 1626s, 1587s,
1568w, 1481s, 1434s, 1420m, 1363m, 1282s, 1286m, 1239m, 1227m, 1207m,
1108m, 1082m, 1050s, 936m, 833s, 780s, 760s, 752s, 565m, 539s, 521s, 493m,
453m, 408m and 311s. 1HNMR (200 MHz in CDCl3, δ(ppm) relative to
TMS): 1.37 (s, 18H, tert-butyl), 6.62Ϫ8.45 (aromatic hydrogens)
´
[14] U. Mukhopadhyay, D. Choquesillo-Lazarte, J. Niclos-Gutier-
rez, I. Bernal, CrystEngComm 2004, 6(102), 627Ϫ632.
[15] G. A. Jeffrey, H. Maluszynska, J. Mitra, Int. J. Biol. Macro-
mol. 1985, 7, 336Ϫ348.
[16] A. L. Spek, PLATON program, J. Appl. Cryst. 2003, 36, 7.
[17] Bruker AXS Inc., Madison, Wisconsin, USA, © 2005, SAINT
(Version 7.06A), SADABS (Version 2.10).
[18] G. M. Sheldrick, SHELXS97, Program for Crystal Structure
solution. 1997, University of Göttingen, Germany.
[19] G. M. Sheldrick, SHELXL97, Program for crystal structure
Refinement, 1997, University of Göttingen, Germany.
[20] L. J. Farrugia, WinGX program, J. Appl. Cryst. 1999, 32.
Properties of 2. Yield, 81 %; m.p. 279Ϫ280 °C; C,H,N analysis:
calcd. for 760.65 gmolϪ1, C, 53.6; H, 4.2; N, 7.4 %; found, C, 53.3;
H, 4.1; N, 7.2 %.
IR spectroscopy (CsI pellet and nujol film between polyethylene sheets),
cmϪ1: 3060m, 2989s, 2967s, 2907m, 2871m, 2137vs, 2126s, 2062m, 2063m,
1666m, 1626s, 1600m, 1588s, 1482s, 1437s, 1363m, 1283m, 1240m, 1203m,
1109m, 1081m, 1050m, 938m, 833m, 779s, 758s, 563m, 539s, 491m, 452s,
417m, 407s,277s, 246m, 119m and 82m. 1HNMR (200 MHz in CDCl3,
δ(ppm) relative to TMS: 1.42 (s, 18H, tert-butyl), 6.63Ϫ8.56 (aromatic
hydrogens)
1900
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Z. Anorg. Allg. Chem. 2008, 1896Ϫ1900