Metal chelates of N-benzothiazol-2-yl-, N-benzoxazol-2-yl- and N-(1H-benzimidazol-2-yl)-benzamide

Article abstract of DOI:10.1016/S0020-1693(00)00109-2

The synthesis of the title ligands N-benzothiazol-2-yl-benzamide (1), N-benzoxazol-2-yl-benzamide (2) and N-(1H-benzimidazol-2-yl)-benzamide (3) is described. The molecular structure of 1 confirms the localization of a hydrogen atom at the nitrogen atom of the benzamide group. The ligands form 2:1 metal chelates under deprotonization with Cu(II), Ni(II), Pd(II) and Zn(II). 3 gives a cationic silver(I) complex. The complexes were characterized by XPS, NMR, and FAB mass spectroscopy. The molecular structure of two complexes was determined. (C) 2000 Elsevier Science S.A.

Full text of DOI:10.1016/S0020-1693(00)00109-2

www.elsevier.nl/locate/ica
Inorganica Chimica Acta 305 (2000) 38–45
Metal chelates of N-benzothiazol-2-yl-, N-benzoxazol-2-yl- and
N-(1H -benzimidazol-2-yl)-benzamide
a,
a
b
Jorge Angulo-Cornejo *1, Maria Lino-Pacheco , Rainer Richter , Lothar Hennig b,
Karl-Heinz Hallmeier , Lothar Beyer *2
b
b,
a Uni6ersidad Nacional Mayor de San Marcos Lima, Facultad de Qu´ımica e Ingenier´ıa Qu´ımica, Lima, Peru
b Uni6ersita¨t Leipzig, Fakulta¨t fu¨r Chemie und Mineralogie, D-04103 Leipzig, Germany
Received 24 November 1999; accepted 28 February 2000
Abstract
The synthesis of the title ligands N-benzothiazol-2-yl-benzamide (1), N-benzoxazol-2-yl-benzamide (2) and N-(1H -benzimid-
azol-2-yl)-benzamide (3) is described. The molecular structure of 1 confirms the localization of a hydrogen atom at the nitrogen
atom of the benzamide group. The ligands form 2:1 metal chelates under deprotonization with CuII, NiII, PdII and ZnII. 3 gives
a cationic silver(I) complex. The complexes were characterized by XPS, NMR, and FAB mass spectroscopy. The molecular
structure of two complexes was determined. © 2000 Elsevier Science S.A. All rights reserved.
Keywords: Crystal structures; Benzamide complexes; Transition metal complexes
1. Introduction
are also of interest with respect to their connection to
purin bases [6].
Previous investigations of synthesis and characteriza-
tion of metal complexes with guanidine and isourea
structural elements [1–3] are followed now by studies of
metal complexes from title ligands N-benzothiazol-2-yl-
benzamide (1), N-benzoxazol-2-yl-benzamide (2), and
N-(1H -benzimidazol-2-yl)-benzamide (3) (Scheme 1).
Metal complexes (mainly Zn(II)) with guanidinium
structure and from benzimidazoles and related com-
pounds are known as protease inhibitors [4] or are used
in structure investigation of metallo proteins [5]. They
2. Experimental
All chemicals and solvents were dried and purified by
the usual methods. Melting points are corrected and
were measured using a Boetius melting-point appara-
tus. Mass spectra were recorded on a Masslab VG
12-250 device and for the ESI-spectrum of 3e on a
LC-MS Platform 1 spectrometer, Fa. Micromass (1:1
H2O/acetonitrile). NMR spectra were recorded on a
Unity 400 spectrometer, 1H: | (ppm), 399.95 MHz,
solvent DMSO-d6; 13C: | (ppm), 100.58 MHz, solvent
DMSO-d6. The XPS spectra were recorded on a VG
ESCALAB 200i XL (Vaccuum Generators).
2.1. Synthesis of compounds 1–6: general procedure
N-(Ethoxyethylsulfanylmethylene)-benzamide (0.07
mol) [7] in 75 ml ethanol was treated with an equivalent
amount of the corresponding ortho-substituted aniline
(2-amino-benzenethiol for 1, 2-aminophenol for 2, ben-
zene-1,2-diamine for 3 [2], (3,4-diaminophenyl)-phenyl-
methanone for 4, and 2-amino-4-methylphenol for 5)
Scheme 1.
1 *Corresponding author.
2 *Corresponding author. Tel.: +49-341-973 6161; fax: +49-341-
973 6199; e-mail: beyinorg@organik.chemie.uni-leipzig.de
0020-1693/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII: S0020-1693(00)00109-2

J. Angulo-Cornejo et al. / Inorganica Chimica Acta 305 (2000) 38–45
39
Scheme 2.
dissolved in the same quantity of ethanol. The mixture
was stirred and refluxed for 4 h. An intensive smell of
ethanethiol was observed. Then the mixture was stirred
for further 12 h and kept in the refrigerator. The
formed precipitate was filtered, recrystallized and air
dried. Compound 6 was formed directly from 5 by
melting (Scheme 2).
531.6, 534.4; C1s 285.0, 286.3, 288.7. 1H NMR [l,
DMSO-d6]: 12.16 s (br, 1H); 8.05 d (2H); 7.49–7.66 m
(5H); 7.24–7.38 m (2H). 13C NMR [l, DMSO-d6,
APT]: 167 (br, C-q); 156.85 (br, C-q); 147.14 (br, C-q);
133.85 (C-q); 132.90 (CH); 128.80 (CH); 128.74 (CH);
124.96 (CH); 124.16 (CH); 117.44 (br, CH); 110.47
(CH).
2.1.1. N-Benzothiazol-2-yl-benzamide (1)
2.1.2.1. Alternati6e synthesis from 1-benzoyl-3-(2-hy-
droxyphenyl)thiourea and mercury(II) acetate. 1-Benz-
oyl-3-(2-hydroxyphenyl)thiourea (1.36 g, 0.005 mol) [8]
was dissolved in 40 ml methanol. To this solution 1.6 g
(0.005 mol) Hg(CH3COO)2 in hot methanol (20 ml) was
added. The mixture was refluxed and stirred for 30 min
at 40°C. The black precipitate of HgS was filtered and
washed with hot methanol. The solution was stored in
the refrigerator. The white–lightly yellow precipitate
was filtered and washed with a little cold methanol. The
precipitate was desiccated at room temperature (r.t.) for
24 h.
Yield: 0.4 g (34%); m.p.: 189–191°C, white–light
yellow crystals. Anal. Calc. for C14H10N2O2 (238.22 g
mol−1): C, 70.58; H, 4.23; N, 11.76; O, 13.4. Found: C,
69.20; H, 4.34; N, 11.60; O, 13.60%. MS [m/z] 238
(M+, 23% rel. int.); 209.9 (M+−CO, 2%); 105
(PhCO+, 100%); 77 (Ph+, 50%); 50.4 (C4H+2 , 15%).
Yield: 57%; m.p.: 187–189°C (ethanol), light yellow
crystals. Anal. Calc. for C14H10N2OS (254.30 g mol−1):
C, 66.12; H, 3.96; N, 11.02; O, 6.29; S, 12.61. Found: C,
66.10; H, 3.78; N, 10.60; O, 6.44; S, 13.30%. MS [m/z]:
254 (M+, 29.3% rel. int.); 226 (M+−CO, 11.4%); 105
(PhCO+, 100%); 77 (Ph+, 50%). XPS [eV]: N1s 399.1
(ꢀNꢁ); 400.6 (ꢀNHꢀ); S2p 164.5 (ꢀSꢀ); O1s 531.9; 534.0;
1
C1s 285.0; 287.9. H NMR [l, DMSO-d6]: 12.91 s (br,
1H); 8.14 d (2H); 8.00 d (1H); 7.78 d (2H); 7.49–7.69 m
(3H); 7.49 dd (1H); 7.32 dd (1H). 13C NMR: [l,
DMSO-d6] 167.07 (C-q); 159.97 (C-q); 149.24 (C-q);
133.84 (CH); 132.93 (C-q); 132.48 (C-q); 129.61 (CH);
129.32 (CH); 127.15 (CH); 124.65 (CH); 122.70 (CH);
121.28 (CH).
2.1.2. N-Benzoxazol-2-yl-benzamide (2)
Yield: 45%; m.p.: 188–190°C (ethanol), white–light
yellow crystals. Anal. Calc. for C14H10N2O2 (238.22 g
mol−1): C, 70.58; H, 4.23; N, 11.76; O, 13.43. Found:
C, 70.20; H, 4.47; N, 11.30; O, 13.8%. MS [m/z] 238
(M+, 20.7% rel. int.); 105 (PhCO+, 100%); 77 (Ph+,
45%). XPS [eV]: N1s 398.8 (ꢀNꢁ); 400.9 (ꢀNHꢀ); O1s
2.1.3. N-(1H -Benzimidazol-2-yl)-benzamide (3)
Elemental analysis, mass spectra, and NMR data
already have been published [2]. The results are now
completed by XPS data.

40
J. Angulo-Cornejo et al. / Inorganica Chimica Acta 305 (2000) 38–45
XPS [eV]: N1s 398.8 (ꢀNꢁ), 400.5 (ꢀNHꢀ); O1s 531.8,
534.0; C1s 285.0, 288.1.
2.2. Synthesis of complexes (1a, 1c; 2a, 2b; 3a, 3b, 3d,
3e): general procedure
2.1.4. 1-(2-Aminobenzoylphenyl)-3-benzoyl-2-
ethylisourea (4)
Ligands 1–3 (0.002 mol) were dissolved in 50–100 ml
ethanol. With heating and stirring 0.001 mol of the
Yield 54%; m.p.: 153–156°C, yellow crystals. Anal.
Calc. for C23H21N3O3 (387 g mol−1): C, 71.32; H, 5.43;
N, 10.85; O, 12.40. Found: C, 70.20; H, 5.39; N, 10.60;
O, 11.60%. MS [m/z] 386.9 (M+, 0.5% rel. int.); 340.9
(M+−OC2H5, 0.5%); 312.7 (M+−OC2H5−CO,
0.2%); 211.8 (PhCOC6H3(p-NH2)(m-NH)+, 25%); 134
(PhCONHCH+2 , 22%); 105.1 (PhCO+, 20%); 77.1 (Ph+,
corresponding
metal
acetate
[Cu(OAc)2·H2O;
Ni(OAc)2·4H2O; Zn(OAc)2, Pd(OAc)2], and silver(I) ni-
trate (for 3e), respectively, dropwise was added. In the
case of 3b the mixture was additionally treated with 1 g
pyridine. The mixture was stored in the refrigerator
overnight. The separated crystals were recrystallized
and dried.
1
12%), 44.1 (CONH+2 , 100%). H NMR [l, DMSO-d6]:
11.22 s (br, 1H); 8.22 d (2H); 7.49–7.69 m (10H); 6.89
d (1H); 6.19 s (br, 2H, NH2); 4.52 q (2H, OCH2); 1.29
t (3H, CH3). 13C NMR [l, DMSO-d6]: 193.50 (CO);
176.64; 161.72; 148.67; 138.84; 137.54; 132.26; 131.64;
130.43; 130.25; 129.26; 129.15; 128.53; 128.44; 124.51;
119.90; 114.99; 64.14 (OCH2); 14.58 (CH3).
2.2.1. Bis[N-(benzothiazol-2-yl)-benzamidato)]copper(II)
(1a)
Yield: 88%; m.p.: 287–289°C, olive–green crystals.
Anal. Calc. for C28H18CuN4O2S2 (569.54 g mol−1): C,
58.99; H, 3.16; N, 9.83; O, 5.62; S, 11.24; Cu, 11.16.
Found: C, 58.90; H, 3.14; N, 9.89; O, 5.88; S, 11.50%.
XPS [eV] N1s 399.0 (ꢀNꢁ), 399.9 (ꢀNꢀCuꢀ); S2p3/2
164.6 (ꢀSꢀ); Cu2p3/2 935.5, 940.7, 945.0 (Cu-coordi-
nated); O1s 532.3 (CꢀOꢀCu), 534.2; C1s 285.0, 285.8,
287.8 This product was recrystallized from DMF for
X-ray structure analysis. Anal. Calc. for C28H18-
CuN4O2S2·dmf (642.54 g mol−1): C, 57.90; H, 3.89; Cu,
9.89; N, 10.89; O, 7.47; S, 9.96. Found: C, 57.20; H,
3.93; Cu, 9.45; N, 10.80; O, 7.25; S 10.00%.
2.1.5. 1-Benzoyl-2-ethyl-3-(2-hydroxy-5-methylphenyl)-
isourea (5)
Yield: 30%; m.p.: 137–142°C, chestnut-colored crys-
tals. Anal. Calc. for C17H19N2O3 (298.12 g mol−1): C,
68.46; H, 6.04; N, 9.16; O, 16.20. Found: C, 67.60; H,
5.93; N, 9.16, O, 16.20%. MS [m/z] 297.9 (M+, 10% rel.
int.), 251.9 (M+−C2H5O, 12%); 176.9 (PhC(O)Nꢁ
COC2H+5 , 43%); 148.9 (PhC(O)NꢁCNH+2 +2H, 33%);
121.9 (PhC(O)NH++2H, 8%); 105.2 (PhCO+, 100%);
94.3 (PhNH+3 , 4%), 77 (Ph+, 32%); 50.4 (C4H+2 , 3%).
1H NMR [l, DMSO-d6]: 12.01 s (br, 1H); 9.99 s (br,
1H); 8.19 d (2H); 7.42–7.55 m (4H); 6.81 dd (2H); 4.61
2.2.2. Bis[N-(benzothiazol-2-yl)-benzamidato]zinc(II)
(1c)
Yield: 70%; m.p.: 347–349°C, white crystals. Anal.
Calc. for C28H18N4O2S2Zn (572.0 g mol−1): C, 58.80;
H, 3.17; N, 9.80; S, 11.21; Zn, 11.43. Found: C, 56.40;
H, 3.48; N, 9.01; S, 11.10; Zn, 10.59%. XPS [eV] N1s
398.9 (ꢀNꢁ), 399.9 (ꢀNZnꢀ); S2p 164.6 (ꢀSꢀ); Zn 2p3/2
1022.8; O1s 532.3, 534.0, C1s 285.0, 285.8, 287.8.
q
(2H, OCH2); 2.21 s (3H, CH3); 1.40 t (3H,
OCH2CH3). 13C NMR [l, DMSO-d6]: 177.04; 160.94;
146.32; 138.17; 132.99; 129.94; 129.16; 128.82; 126.51;
124.99; 123.36; 115.91; 65.07 (OCH2); 21.43 (CH3);
15.12 (OCH2CH3).
2.2.3. Bis[N-(benzoxazol-2-yl)-benzamidato)]copper(II)
(2a)
2.1.6. N-(5-Methylbenzoxazol-2-yl)-benzamide (6)
Complex 5 (200 mg, 0.0007 mol) was heated for 30
min at 150°C, followed by a short time of 200°C. The
substance changes to a red oil. The oil was stored at r.t.
and a few milliliters of acetone was added. The solution
was stored in the refrigerator. The precipitate 6 was
filtered, washed and desiccated at r.t.
Yield: 93%; m.p.: 309–311°C, dark green crystals.
Anal. Calc. for C28H18CuN4O4 (537.54 g mol−1): C,
62.51; H, 3.35; Cu, 11.82; N, 10.42; O, 11.91. Found: C,
62.00; H, 3.36; Cu, 11.22; N, 10.40; O, 11.70%. MS-
FAB [m/z] 537.3 (M+, 11% rel. int.), 405 (M+
−
Ph(N)(O)CꢁN, 37%); 300 (M+−L, 37%); 238.1 (L+,
33%); 194.9 (CuPh(N)(O)CꢁN, 17.6%); 106 (PhCOH+,
100%); 77 (Ph+, 21%). XPS [eV] N1s 399.0 (ꢀNꢁ), 399.8
(ꢀNꢀCu); Cu2p3/2 935.6, 941.6, 945.0 (Cu-coordi-
nated); O1s 532.3 (CꢀOꢀCu), 534.4; C1s 285.0, 285.7,
288.4.
Yield: 50 mg (30%); m.p.: 178–180°C, yellow crys-
tals. MS [m/z]: 251.8 (M+, 27% rel. int.); 223.8 (M+
−
CO, 1.4%); 105 (PhCO+, 100%); 77 (Ph+, 34%); 50.4
1
(C4H+2 , 5%). H NMR [l, DMSO-d6]: 12.09 s (br, 1H);
8.07 d (2H); 7.47–7.65 m (4H); 7.40 s (1H); 7.11 d
(1H); 2.41 s (3H). 13C NMR [l, DMSO-d6, APT]: 166.5
(br, C-q); 157.03 (br, C-q); 145.06 (br, C-q); 138.39 (br,
C-q); 134.37 (C-q); 133.95 (br, C-q); 132.83 (CH);
128.76 (2×CH); 124.90 (CH); 117.43 (br, CH); 109.91
(CH); 21.29 (CH3).
2.2.4. Bis(methanol)-bis[N-(benzoxazol-2-yl)-
benzamidato]nickel(II) (2b)
Yield: 67%; m.p.: 285–287°C, light green crystals.
Anal. Calc. for C28H18N4NiO4·2CH3OH (597.25 g

J. Angulo-Cornejo et al. / Inorganica Chimica Acta 305 (2000) 38–45
41
mol−1): C, 60.33; H, 4.39; N, 9.38; Ni, 9.83; O, 16.07.
Found: C, 59.70; H, 4.31; N, 9.22; Ni, 10.10%. MS-
FAB [m/z] 533.2 (M+−2CH3OH, 39% rel. int.), 105.1
(Ph+, 100%). XPS [eV] N1s 398.8 (ꢀNꢁ), 399.7
(ꢀNꢀNi); Ni2p3/2 856.3, 862.1 (Ni-coordinated); O1s
532.3 (CꢀOꢀNi), 534.4; C1s 285.0, 286.4, 288.1.
The structures were solved and refined by SHELX-97
[9]. The positions of all hydrogen atoms were taken
from difference syntheses and refined with isotropic
temperature factors 1.2 times higher than Ueq of the
parent C, N or O atoms.
Details of crystal data and structural determinations
are given in Table 1. Tables 2–4 show selected bond
distances and angles.
2.2.5. Bis[N-(benzimidazol-2-yl)-benzamidato]copper(II)
(3a)
Synthesis, elemental analysis and mass spectra were
already reported in our late work [2]. XPS [eV] N1s
399.1 (ꢀNꢁ), 399.6 (ꢀNꢀCu), 400.6 (ꢀNHꢀ); Cu2p3/2
935.4, 943.5, 945.6 (Cu-coordinated); O1s 532.4
(CꢀOꢀCu), 534.3; C1s 285.0, 285.7, 287.9.
3. Results and discussion
3.1. Synthesis and spectroscopic characterization of
ligands and metal complexes
2.2.6. Bis(pyridine)-bis[N-(benzimidazol-2-yl)-
benzamidato]nickel(II) (3b)
Synthesis of ligands 1–3 was performed easily by
reaction of N-(ethoxyethylsulfanylmethylene)-benz-
amide [7] and ortho-substituted aniline derivatives
XꢀC6H4ꢀNH2 (X=ꢀSH; ꢀOH; ꢀNH2) in boiling
ethanol (Scheme 3). Compounds 1–3 were obtained as
crystals in very good yields (90%) and are pure after
one recrystallization. Compound 1 furnished suitable
single crystals for X-ray analysis.
Under the same conditions educts (3,4-di-
aminophenyl)phenylmethanone and 2-amino-4-methyl-
phenol, respectively, gave with N-(ethoxyethylsulfanyl-
methylene)benzamide only isoureas 4 and 5 with elimi-
nation of ethanethiol. Complex formation of these
compounds has not been investigated (within this
work).
Yield: 87%; m.p.: \285°C (dec.), blue–gray crystals.
Anal. Calc. for C28H20N6NiO2·2Pyr (689.31 g mol−1):
C, 66.21; H, 4.38; N, 16.25; Ni, 8.51; O, 4.64. Found:
C, 65.65; H, 4.56; N, 16.05; Ni, 7.89; O, 4.47%. XPS
[eV] N1s 399.1 (ꢀNꢁ), 400.1 (ꢀNꢀNi), 400.8 (ꢀNHꢀ),
Ni2p3/2 856.4, 861.6, 864.6 (Ni-coordinated); O1s 531.8
(CꢀOꢀNi), 532.8; C1s 285.0, 285.7, 287.8, 292.3 (sat.).
2.2.7. Bis[N-(benzimidazol-2-yl)-benzamidato]-
palladium(II)hydrate (3d)
Yield: 85%; m.p.: \365°C, yellow crystals. Anal.
Calc. for C28H20N6O2Pd·H2O (596.42 g mol−1): C,
56.34; H, 3.69; N, 14.08; O, 8.05. Found: C, 56.6; H,
3.62; N, 13.70; O, 6.96%. XPS [eV] N1s 399.4 (ꢀNꢁ),
399.7 (ꢀNꢀPd), 400.6 (ꢀNHꢀ); Pd 3d5/2 338.9; O1s
532.6 (CꢀOꢀPd), 534.3, 536.6; C1s 285.0, 285.8, 287.8,
289.8.
We found that compound 5 melts over the large
temperature range 137–142°C. During the melting pro-
cess new crystals formed immediately and these had a
sharp melting point of 178–180°C. This effect is caused
by conversion of 5 with elimination of C2H5OH to
form compound 6 (see Scheme 2).
2.2.8. Bis[N-(benzimidazol-2-yl)-benzamide]-
sil6er(I)nitrate (3e)
Another new access route for ligand 2 was found by
reaction of 1-benzoyl-3-(2-hydroxyphenyl)thiourea [8]
with mercury(II) acetate in methanol, proceeding with
ring closure by loss of sulphur (see Scheme 4). In this
case the yields are lower contrary to the described
method above. An optimization of the yield has not
been done.
Synthesis of copper(II) complex from ligand 3 and its
molecular structure has been described recently [2]. In
this paper we report about complexes of 1 with cop-
per(II) and zinc(II), of 2 with copper(II) and nickel(II)
as well as of 3 with nickel(II), palladium(II), and sil-
ver(I) which have been obtained by reaction of the
ligands with the corresponding metal(II) acetates (CuII,
NiII, ZnII, PdII) and nitrate (AgI), respectively, in
ethanolic solution. In most cases (with exception of
silver(I) complex 3e) 2:1 neutral metal chelates were
formed with deprotonation of the ligand. The dark
green copper(II) complexes 1a and 3a [2] easily can be
recrystallized from DMF with inserting one DMF sol-
Yield: 88%; m.p.: 269–271°C, colorless crystals.
Anal. Calc. for C28H20AgN7O5 (641.87 g mol−1): C,
52.34; H, 3.12; Ag, 16.81; N, 15.27; O, 12.46. Found: C,
51.80; H, 3.45; N, 14.80; O, 12.20%. ESI-MS+ [m/z]:
581 (AgL+2 , 93% rel. int.); 344 (AgL+, 19.9%); 238
(LH+, 100%). XPS [eV] N1s 399.4 (ꢀNꢁ), 400.8
(ꢀNHꢀ), 406.7 (NO3−); Ag 3d 5/2 369.0; O1s 532.1
(CꢀOꢀAg), 533.7; C1s 285.0, 285.6, 288.3.
2.3. X-ray structural determination
All measurements were carried out on a Siemens
CCD SMART diffractometer equipped with a graphite
monochromator utilizing Mo Ka radiation (u=
,
0.71073 A).
The data were collected for 1 at r.t. and for 1a and 2b
at −53°C. Lorentz-polarization corrections and ab-
sorption corrections by SADABS were applied to the
intensity data.

42
J. Angulo-Cornejo et al. / Inorganica Chimica Acta 305 (2000) 38–45
Table 1
Crystallographic and structural determination data
1
1a
2b
Molecular formula
Formula weight (g mol−1
Crystal habit, color
Crystal system
C14H10N2OS
254.30
yellowish prisms
monoclinic
P 21/n
C
31H25CuN5O3S2
C30H26N4NiO6
597.26
light-green prisms
monoclinic
P 21/c
)
643.22
olive–green prisms
monoclinic
P 21/c
Space group
,
a (A)
5.9515(4)
16.8803(11)
11.9488(8)
102.390(1)
1172.5(1)
4
11.3666(2)
21.0299(3)
12.4076(2)
107.536(1)
2828.1(1)
4
7.1268(4)
19.5319(12)
10.3610(7)
106.829(1)
1380.5(2)
2
,
b (A)
,
c (A)
i (°)
V (A )
3
,
Z
Dcalc (g cm−3
F(000)
)
1.441
528
1.511
1324
1.437
620
Crystal size (mm)
Linear absorption coefficient v
(mm−1
0.42×0.25×0.13
0.263
0.43×0.17×0.11
0.963
0.27×0.25×0.18
0.754
)
Temperature (K)
2q Range (°)
298
220
220
4–56
6428
2507
2057
3–55
14807
5633
4884
4–55
7127
2729
2387
Measured reflections
Unique reflections
Observed reflections (I]2|(I))
Structure solution
Structure refinement
Refined parameters
wR2
direct methods
Patterson
Patterson
a
a
a
204
455
227
0.1058 for 2507 unique
reflections
0.1377 for 5633 unique
reflections
0.1241 for 2729 unique reflections
R1
0.0393 for 2057 observed
reflections
0.0553 for 4884 observed
reflections
0.0470 for 2387 observed
reflections
Greatest difference peak and hole
0.08 and −0.39
0.17 and −1.23
0.16 and −1.02
−3
,
(e A
)
a Anisotropic LS refinement of non-hydrogen atoms and isotropic LS refinement of hydrogen atoms.
vent molecule per complex into the coordination poly-
hedron in the crystalline state. In the light green nick-
el(II) chelate complexes either two molecules of the
Table 2
solvent methanol (2b) or two molecules of the deproto-
,
Selected distances (A) and angles (°) for 1
nating agent pyridine (3b) coordinate together with two
ligands. Zinc(II) complex 1c is of interest with respect
to the above mentioned papers [4–6]. But it was not
possible to get single crystals of it until now. Silver(I)
complex 3e consists of cationic complex unit [Ag(3)2]+
and nitrate ion.
From the ESCA, mass and NMR spectroscopic in-
vestigations result the following statements: the N1s
peaks of the ligands 1–3 consists of two components.
The lower energy component (1: 399.1 eV; 2: 398.8 eV;
3: 398.8 eV) originates from the binding fragment ꢀNꢁ.
As shown by X-ray structure analysis this fragment is
in case 1 localized in the thiazole ring. The higher
binding energy component (1 400.6 eV; 2 400.9 eV; 3
400.5 eV) results from the binding fragment ꢀNHꢀ. In
the coordinated ligands this N1s signal is shifted, with
exception of the silver(I) complex 3e, to binding energy
values lower than 400 eV. Therefore the difference of
both signals is reduced (for instance 1a: 399.7, 398.8 eV;
Bond lengths
S1ꢀC2
S1ꢀC3
O1ꢀC1
N1ꢀC2
N1ꢀC4
N2ꢀC1
N2ꢀC2
N2ꢀH2
1.749(2)
1.741(2)
1.217(2)
1.299(2)
1.398(2)
1.372(2)
1.383(2)
0.82(2)
C1ꢀC9
C3ꢀC4
C3ꢀC8
C4ꢀC5
C5ꢀC6
C6ꢀC7
C7ꢀC8
1.490(2)
1.399(3)
1.396(3)
1.395(3)
1.381(3)
1.388(3)
1.374(3)
Bond angles
C2ꢀS1ꢀC3
C2ꢀN1ꢀC4
C1ꢀN2ꢀC2
C1ꢀN2ꢀH2
C2ꢀN2ꢀH2
O1ꢀC1ꢀN2
O1ꢀC1ꢀC9
N2ꢀC1ꢀC9
S1ꢀC2ꢀN1
S1ꢀC2ꢀN2
N1ꢀC2ꢀN2
87.98(9)
109.5(2)
124.3(2)
118(2)
S1ꢀC3ꢀC4
S1ꢀC3ꢀC8
C4ꢀC3ꢀC8
N1ꢀC4ꢀC3
N1ꢀC4ꢀC5
C3ꢀC4ꢀC5
C4ꢀC5ꢀC6
C5ꢀC6ꢀC7
C6ꢀC7ꢀC8
C3ꢀC8ꢀC7
110.1(1)
128.6(2)
121.3(2)
115.1(2)
125.5(2)
119.5(2)
118.7(2)
121.4(2)
120.8(2)
118.3(2)
117(2)
122.0(2)
122.4(2)
115.5(2)
117.4(1)
121.8(1)
120.8(2)

J. Angulo-Cornejo et al. / Inorganica Chimica Acta 305 (2000) 38–45
43
Table 3
plex compound 3e contains intense fragment ions at
m/z 581 (AgL+2 ), 344 (AgL+) and 238 (LH+) and also
a lower intense fragment at m/z 927, which can be
explained by the cation Ag2L+3 . Therefore, it can be
concluded that such species also exist in solution. The
NMR spectra are also in agreement with the structure
of compounds 1–6 (see Section 2).
,
Selected distances (A) and angles (°) for 1a
Bond lengths
Cu1ꢀO1
Cu1ꢀN1
S1ꢀC2
1.953(2)
1.968(2)
1.763(3)
1.740(3)
1.282(4)
1.335(4)
1.403(4)
1.333(4)
1.352(4)
1.494(4)
1.401(4)
1.403(4)
1.405(4)
1.381(5)
1.395(5)
1.387(5)
2.294(2)
1.324(4)
1.460(5)
Cu1ꢀO2
Cu1ꢀN3
S2ꢀC16
1.952(2)
1.974(3)
1.765(3)
1.744(3)
1.276(4)
1.328(4)
1.404(4)
1.336(4)
1.348(4)
1.489(4)
1.402(4)
1.395(4)
1.400(4)
1.380(5)
1.402(5)
1.389(5)
1.225(4)
1.448(5)
S1ꢀC3
S2ꢀC17
O1ꢀC1
N1ꢀC2
N1ꢀC4
N2ꢀC1
N2ꢀC2
C1ꢀC9
C3ꢀC4
C3ꢀC8
C4ꢀC5
C5ꢀC6
C6ꢀC7
C7ꢀC8
Cu1ꢀO3
N5ꢀC29
N5ꢀC31
O2ꢀC15
N3ꢀC16
N3ꢀC18
N4ꢀC15
N4ꢀC16
C15ꢀC23
C17ꢀC18
C17ꢀC22
C18ꢀC19
C19ꢀC20
C20ꢀC21
C21ꢀC22
O3ꢀC29
N5ꢀC30
3.1.1. X-ray structural determination of N-benzo-
thiazol-2-yl-benzamide (1), dimethylformamide-
bis[N-(benzothiazol-2-yl)-benzamidato]copper(II) (1a)
and bis(methanol)-bis[N-(benzoxazol-2-yl)-
benzamidato]nickel(II) (2b)
The molecular structures of the investigated com-
pounds 1, 1a and 2b are shown in Figs. 1–3.
Structure 1 is a benzothiazole derivative with a dou-
,
ble bond between N1 and C2 (1.299 A) and a single
,
bond between N1 and C4 (1.398 A). The hydrogen
atom H2 is bonded to N2. The possible tautomeric
form of a benzothiazoline derivative with a hydrogen
atom bonded to N1 is not observed. With exception of
the phenyl ring C9ꢀC14 the molecule is mostly planar.
The angle between the phenyl ring C9ꢀC14 and the rest
of the molecule is 39.1°.
Bond angles
O1ꢀCu1ꢀN1
C2ꢀS1ꢀC3
Cu1ꢀO1ꢀC1
Cu1ꢀN1ꢀC2
Cu1ꢀN1ꢀC4
C2ꢀN1ꢀC4
C1ꢀN2ꢀC2
O1ꢀC1ꢀN2
O1ꢀC1ꢀC9
N2ꢀC1ꢀC9
S1ꢀC2ꢀN1
S1ꢀC2ꢀN2
N1ꢀC2ꢀN2
S1ꢀC3ꢀC4
S1ꢀC3ꢀC8
C4ꢀC3ꢀC8
N1ꢀC4ꢀC3
N1ꢀC4ꢀC5
C3ꢀC4ꢀC5
C4ꢀC5ꢀC6
C5ꢀC6ꢀC7
C6ꢀC7ꢀC8
C3ꢀC8ꢀC7
Cu1ꢀO3ꢀC29
C29ꢀN5ꢀC31
89.4(1)
90.3(1)
O2ꢀCu1ꢀN3
C16ꢀS2ꢀC17
Cu1ꢀO2ꢀC15
Cu1ꢀN3ꢀC16
Cu1ꢀN3ꢀC18
C16ꢀN3ꢀC18
C15ꢀN4ꢀC16
O2ꢀC15ꢀN4
O2ꢀC15ꢀC23
N4ꢀC15ꢀC23
S2ꢀC16ꢀN3
89.5(1)
90.4(1)
126.2(2)
122.4(2)
125.8(2)
111.7(2)
119.8(2)
127.8(3)
115.5(3)
116.7(3)
113.5(2)
115.8(2)
130.7(3)
109.7(2)
129.1(2)
121.2(3)
114.7(3)
125.6(3)
119.6(3)
118.9(3)
121.2(3)
120.8(3)
118.2(3)
139.9(2)
121.6(4)
126.5(2)
121.8(2)
125.1(2)
112.5(2)
119.8(3)
127.3(3)
115.6(3)
117.2(3)
113.1(2)
115.8(2)
131.1(3)
109.6(2)
128.9(2)
121.6(3)
114.4(3)
126.1(3)
119.5(3)
118.8(3)
121.5(3)
120.3(3)
118.3(3)
119.9(3)
118.4(4)
Both NꢀC bonds involving N2 differ only slightly
,
(1.372 and 1.383 A). O1 and S1 are cis arranged
(~(O1C1N2C2) 13.0(3)° and ~(S1C2N2C1) −1.8(3)°).
In the crystal structure of 1 a hydrogen bond between
N2 and N1 [−x +1, −y+2, −z] is observed
,
,
(N2···N1 3.075 A, H2···N1 2.28 A, N2ꢀH2···N1 163.0°)
which leads to pairs of molecules.
S2ꢀC16ꢀN4
N3ꢀC16ꢀN4
S2ꢀC17ꢀC18
S2ꢀC17ꢀC22
C18ꢀC17ꢀC22
N3ꢀC18ꢀC17
N3ꢀC18ꢀC19
C17ꢀC18ꢀC19
C18ꢀC19ꢀC20
C19ꢀC20ꢀC21
C20ꢀC21ꢀC22
C17ꢀC22ꢀC21
C29ꢀN5ꢀC30
C30ꢀN5ꢀC31
In the copper complex 1a of the ligand 1 the copper
central atom is five-coordinated by two deprotonated
Table 4
,
Selected distances (A) and angles (°) for 2b
Bond lengths
Ni1ꢀO1
Ni1ꢀO3
Ni1ꢀN1
O1ꢀC1
O2ꢀC2
O2ꢀC3
O3ꢀC15
N1ꢀC2
N1ꢀC4
2.058(2)
2.112(2)
2.052(2)
1.256(3)
1.382(3)
1.383(3)
1.415(4)
1.320(3)
1.411(3)
N2ꢀC1
N2ꢀC2
C1ꢀC9
C3ꢀC4
C3ꢀC8
C4ꢀC5
C5ꢀC6
C6ꢀC7
C7ꢀC8
1.351(3)
1.351(3)
1.514(4)
1.392(4)
1.388(4)
1.394(4)
1.400(4)
1.391(5)
1.401(4)
1c: 399.9, 398.9 eV; 2a: 399.8, 399.0 eV; 2b: 399.7, 398.8
eV). From this follows without doubt the deprotona-
tion of the NH group during the metal complexation.
Moreover the position of one of the two N1s signals at
399.890.1 eV (in the case 3b 400.1 eV due to the
influence of the two additional pyridine ligands) is of
great evidence for the metal coordination of one of
these nitrogen atoms. This was confirmed in the case of
1a and 2b by X-ray structural analysis.
Bond angles
O1ꢀNi1ꢀN1
Ni1ꢀO1ꢀC1
C2ꢀO2ꢀC3
Ni1ꢀO3ꢀC15
Ni1ꢀN1ꢀC2
Ni1ꢀN1ꢀC4
C2ꢀN1ꢀC4
C1ꢀN2ꢀC2
O1ꢀC1ꢀN2
O1ꢀC1ꢀC9
N2ꢀC1ꢀC9
O2ꢀC2ꢀN1
84.10(8)
128.6(2)
105.0(2)
128.1(2)
120.5(2)
131.7(2)
105.7(2)
118.9(2)
126.5(2)
117.2(2)
116.2(2)
113.2(2)
O2ꢀC2ꢀN2
N1ꢀC2ꢀN2
O2ꢀC3ꢀC4
O2ꢀC3ꢀC8
C4ꢀC3ꢀC8
N1ꢀC4ꢀC3
N1ꢀC4ꢀC5
C3ꢀC4ꢀC5
C4ꢀC5ꢀC6
C5ꢀC6ꢀC7
C6ꢀC7ꢀC8
C3ꢀC8ꢀC7
113.6(2)
133.2(2)
108.3(2)
127.6(3)
124.1(3)
107.7(2)
132.0(2)
120.3(2)
116.6(3)
122.1(3)
121.8(3)
115.0(3)
The mass spectra of the ligands and metal complexes
confirm in all cases their identity by the molecular
peaks. The ES+-mass spectrum for the silver(I) com-

44
J. Angulo-Cornejo et al. / Inorganica Chimica Acta 305 (2000) 38–45
Scheme 3.
Scheme 4.
Fig. 1. Molecular structure of N-benzothiazol-2-yl-benzamide (1).
ligands with N,O-coordination and a DMF molecule.
The coordination polyhedron is a trigonal bipyramid
with the nitrogen atoms N1 and N3 in the axial posi-
tions (N1ꢀCu1ꢀN3 173.1°) and the DMF coordinating
through O3 in an equatorial position (Cu1ꢀO3 2.294
,
A).
The coordination of the benzothiazole ligands results
as expected in lengthening of the O1ꢀC1 (1.217“1.279
,
,
A) and N1ꢀC2 bonds (1.299“1.332 A) and shortening
,
of the N2ꢀC1 (1.372“1.335 A) and N2ꢀC2 bonds
,
(1.383“1.350 A). Surprisingly the S1ꢀC2 bond
(1.749“1.764 A) also becomes longer. The angles be-
,
tween phenyl rings and chelate rings are 17.1 and 10.6°.
The nickel complex 2b shows coordination number 6
with coordination of two ligands 2 and two molecules
of methanol. The complex molecule has an inversion
center at the nickel atom and therefore an octahedral
coordination polyhedron with a trans arrangement of
the ligands. The coordinating atoms of the ligand 2 are
N and O, analogous to 1a. The bond lengths in the
coordinated ligand are comparable with those in 1a. In
Fig. 2. Molecular structure of dimethylformamide-bis[N-(benzothiaz-
ol-2-yl)-benzamidato]copper(II) (1a).

J. Angulo-Cornejo et al. / Inorganica Chimica Acta 305 (2000) 38–45
45
CCDC-140164, -140165, and -140166 for 1, 1a, and 2b,
respectively. Copies of the data can be obtained free of
charge, on application to CCDC, 12 Union Road,
Cambridge, CB2 1EZ, UK (fax: +44-1223-336-033;
e-mail: deposit@ccdc.cam.ac.uk or www: http://
www.ccdc.cam.ac.uk).
Acknowledgements
The authors (J.A-C., M.L-P.) wish to acknowledge
the financial support given by DAAD Bonn.
References
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the crystal structure hydrogen bonds exist between O3
,
,
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4. Supplementary material
Crystallographic data for the structures in this paper
have been deposited with the Cambridge Crystallo-
graphic Data Center as supplementary publication Nos.
.