Synthesis and IR spectral study of MoO2Cl2 molecular complexes with acetoacetanilides. Crystal structure of MoO2Cl2 complex with acetoacet-2-toluidine

Article abstract of DOI:10.1023/A:1026679009037

A series of MoO₂Cl₂ complexes with acetoacetanilide derivatives were synthesized and studied by IR spectroscopy. The crystal and molecular structures of the MoO₂Cl₂ complex with acetoacet-2-toluidine (HL) were determined by X-ray diffraction analysis. The monoclinic crystals involved are a = 7.621(7) A, b = 9.498(3) A, c = 19.980(9) A, β = 95.16(7)°, V = 1440(2) A³, Z = 4, and space group P2₁/n. The coordination polyhedron of the Mo atom is a distorted octahedron with two O oxoatoms in the cis-position relative to each other, two Cl atoms in the trans-positions, and two O atoms (HL) in the trans-positions to O(oxo).

Full text of DOI:10.1023/A:1026679009037

Russian Journal of Coordination Chemistry, Vol. 26, No. 12, 2000, pp. 866–871. Translated from Koordinatsionnaya Khimiya, Vol. 26, No. 12, 2000, pp. 922–927.
Original Russian Text Copyright © 2000 by Abramenko, Sergienko, Churakov.
Synthesis and IR Spectral Study of MoO Cl Molecular
2
2
Complexes with Acetoacetanilides. Crystal Structure
of MoO Cl Complex with Acetoacet-2-Toluidine
2
2
V. L. Abramenko, V. S. Sergienko, and A. V. Churakov
East Ukrainian State University, Lugansk, Ukraine
Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 117907 Russia
Received June 5, 2000
Abstract—A series of MoO Cl complexes with acetoacetanilide derivatives were synthesized and studied by
2
2
IR spectroscopy. The crystal and molecular structures of the MoO Cl complex with acetoacet-2-toluidine (HL)
2
2
were determined by X-ray diffraction analysis. The monoclinic crystals involved are a = 7.621(7) Å, b =
3
9
.498(3) Å, c = 19.980(9) Å, β = 95.16(7)°, V = 1440(2) Å , Z = 4, and space group P2 /n. The coordination
1
polyhedron of the Mo atom is a distorted octahedron with two O oxoatoms in the cis-position relative to each
other, two Cl atoms in the trans-positions, and two O atoms (HL) in the trans-positions to O(oxo).
Solutions of β-diketones and their nitrogen-contain- (A–D) can be suggested in a solution:
ing derivatives (β-enamines, acetoacetanilides) repre-
O
CH3
R PhNH
sent equilibrium mixtures of various tautomers [1] and
can be used to prepare complexes of different types:
adducts (molecular complexes) and chelates [2, 3]. The
type of compound formed is determined by the synthe-
sis conditions and the nature of the reacting compo-
nents. It was reported in [4] that the reaction of molyb-
denum dioxodichloride with β-diketones (β-DicH) in a
benzene–petroleum ether medium at room temperature
yields MoO Cl · β-DicH adducts; however, their struc-
CH3
N
O
O
O
R Ph
H
(
A)
(
B)
R PhNH
CH3
O
CH3
H
O
O
N
O
2
2
R Ph
H
tures were not studied. Under more rigid conditions,
H
MoO (β-Dic) chelates are formed, whose structures
(C)
(D)
2
2
were determined by various methods including X-ray
diffraction [5–7].
This paper reports the results of the study of the
molybdenum dioxodichloride complexes with acetoac-
etanilide (R = H, I) and its derivatives: acetoacet-2-
With β-enamines (HL'), we obtained the molecular
complexes MoO Cl · 2HL' [8, 9] only. The data
toluidine (R = Ó-CH , II), acetoacet-2-anisidine (R = Ó-
3
2
2
CH O, III), and acetoacet-4-chloroanilide (R = p-Cl,
obtained through X-ray diffraction and IR spectroscopy
prove that, in molecular complexes, the neutral ligand
molecules are coordinated by the molybdenum central
atom in the aminoketone (enamine) tautomeric form
through the oxygen atom of the carbonyl group. A sim-
ilar coordination pattern was recently observed in the
adducts of zirconium or titanium tetrachlorides with a
number of β-aminovinylketones [10]. The results of IR
spectral and conductometric studies showed that the
sulfur-containing analogs of β-aminovinylketones are
also coordinated by the central atom in the aminothione
form through the sulfur atoms of the C=S group [11].
3
IV) in nonaqueous solvents. The structures of the iso-
lated complexes are discussed in terms of IR spectral
data. The structure of II was determined by X-ray dif-
fraction.
EXPERIMENTAL
Synthesis of the complexes. A solution of 0.199 g
(
1 mmol) of MoO Cl in ethyl acetate was added under
2 2
the process of stirring to a warm (35–40°ë) solution
containing 1 mmol of the corresponding anilide in
1
5 ml of the same solvent, and the mixture was allowed
It was of interest to study the complexation of Lewis to stay at room temperature for 1 h for crystallization.
acids with acetanilides (HL) that formally combine the The precipitated fine crystals of a lemon color were
functions of β-diketones (A) and β-aminovinylketones separated by filtration, washed with dehydrated ether,
(B) [12, 13], for which the following tautomeric forms and dried in a flow of dry argon.
1
070-3284/00/2612-0866$25.00 © 2000 åÄIä “Nauka /Interperiodica”

SYNTHESIS AND IR SPECTRAL STUDY
867
Table 1. Summary of physicochemical and IR spectral studies of the MoO Cl molecular complexes of acetoacetanilides
2
2
Content, %
anal. calcd./found)
ν, cm–1
(
No.
R
Tm, °C Empirical formula
Mo
195–196 C H Cl MoNO 25.35/25.51 18.97/18.86
Cl
ν(N–H)*
ν(C=O)* ν(Mo–O ) ν(Mo=O)
L
I
H
3315
1690 (1725,
442
458
415
430
945, 915 155
950, 920 162
953, 920 158
947, 915 155
1
0
11
2
4
(
(
(
3300, 3250) 1710, 1660)
II o-CH3 188–190 C H Cl MoNO 24.43/24.60 18.06/18.18
3340
1690 (1720,
11
13
2
4
3270, 3240) 1710, 1670)
III o-OCH 185–187 C H Cl MoNO 23.71/23.63 17.32/17.46
3310 1678 (1720,
3270, 3250) 1710, 1675)
3
11 13
2
5
IV p-Cl
203–205 C H Cl MoNO 23.34/23.39 26.07/25.91 3300 (3290, 1687 (1720,
10 10 3 4
3
250, 3200) 1710, 1657)
*
Frequencies for noncoordinated ligands are given in parentheses.
The metal content of the filtrate was determined by
RESULTS AND DISCUSSION
calcining the weighed sample of the complex to pro-
duce molybdenum trioxide (weight form) [14]. The
chlorine content was determined using the Volhard
method after treatment of the complex with alkali, fol-
lowed by the neutralization of the solution.
IR spectra were recorded on an IKS-29 spectrome-
ter with samples prepared as mineral oil mull.
Unlike β-enamines [8, 9], acetoacetanilides react
with MoO Cl in the ethyl acetate medium to form
2
2
complexes of equimolecular compositions independent
of the initial ratio of the reagents. The obtained complexes
are lemon-colored crystals stable in dry air; they melt at
high temperature without decomposition (Table 1). They
form electrolyte solutions in polar solvents; the molar
–
3
The conductivity of the methanol solutions of the conductivity of the 10 M methanol solutions is 150–
–
3
–1
2
–1
complexes (10 mol/l) was measured at 25°ë on a con- 160 Ω cm mol , which is characteristic of three-ion
ductometer with an ac working frequency of 1000 Hz electrolytes. Dissociation of the complexes in a methanol
using a bridge scheme in a temperature-controlled cell solution may be presented by the following scheme [11]:
with platinized electrodes.
The results of the physicochemical and IR spectral
studies of the complexes are given in Table 1.
MoO Cl ⋅ HL + (x + y)CH OH
2
2
3
2
+
–
[MoO (HL)(CH OH) ] + Cl (CH OH) .
2
3
x
3
y
The X-ray diffraction study of complex II was car-
This is confirmed by the ready precipitation by sil-
ver nitrate of chloride ions from the methanol solutions
of the complexes studied.
ried out on an Enraf-Nonius CAD-4 automated diffrac-
tometer (MoK radiation, λ = 0.71073 Å) at 293 K. The
α
experimental data arrays were corrected for the Lorentz
and polarization factors [15]. The structure was solved
Electronic, vibrational, and NMR spectroscopy are
using the direct method (SHELX86 [16]). All non- widely used in determining the structures of metal
hydrogen atoms were refined by the full-matrix least- complexes with β-diketones and their nitrogen-contain-
2
squares method in anisotropic approximation for F
ing analogs. However, as was noted in [3, 18], the fre-
(
SHELXL93 [17]). All hydrogen atoms were placed in quencies of vibrations of β-diketones and β-enamines
the calculated positions (d(C–H) = 0.96 Å) and then are the complex functions of not only the force con-
refined in isotropic approximation. Crystallographic stants but also of the molecular geometry and steric fea-
data, details of the experiment, and structure II refine- tures of the substituents, thus significantly complicat-
ment are given in Table 2. Coordinates of the non- ing the interpretation of the data.
hydrogen atoms and their equivalent isotropic thermal
As is seen from Fig. 1, the IR spectrum of separate
parameters are listed in Table 3. Bond lengths and
acetanilide is rather complicated; this is typical of pro-
angles are listed in Table 4.
totropic equilibrium systems, in particular, of β-dike-
The unit cell parameters for the crystal of acetoacet- tones and β-enamines [19]. The complexation is
2
-toluidine (V) were determined on an Enraf-Nonius accompanied by the following changes in the IR spec-
CAD-4 automated diffractometer (MoK radiation, λ = tra. A wide band of the stretching vibrations of the N−H
α
–
1
0
.71073 Å) at room temperature. Unfortunately, the bond of the ligand molecule (3300–3150 cm ) remains
low quality of the crystal did not allow a full X-ray dif- unchanged upon complexation but is slightly shifted to
–
1
fraction study. The crystallographic data forV are given higher frequencies by ~60 cm . The absorption bands
in Table 2. of the carbonyl groups of different acetanilide tau-
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 26 No. 12
2000

8
68
ABRAMENKO et al.
Table 2. Crystallographic data and details of the experiment and structure refinement for II and V
Parameter
II
V
Empirical formula
Molecular weight
Crystal system
Space group
a, Å
C H Cl MoNO
C H NO
2
1
1
13
2
4
11 13
390.06
191.23
Monoclinic
Monoclinic
P2 /n
P2 /c
1
1
7.621(7)
9.498(3)
19.980(9)
95.16(7)
1440(2)
4
7.494(7)
12.16(2)
10.816(8)
100.50(7)
962(2)
b, Å
c, Å
β, deg
V, Å3
Z
4
ρ(calcd.), g/cm3
1.799
1.311
F(000)
776
408
–
1
µ(MoK ), mm
1.289
0.090
α
Crystal size, mm
0.5 × 0.4 × 0.2
ω/2.05–24.97
0.3 × 0.2 × 0.2
Scanning type/region for θ, deg
≥
≥
Intervals of reflection indexes
–9
h
9
≥
≥
–
2
k
11
≥
≥
–
3
l
23
Number of measured reflections
Number of unique reflections
Reflections with I > 2σ(I)
Absorption correction
3865
2536 (Rint = 0.0171)
2178
ψ scan mode
Transmission, min/max
Refined parameters
0.4312/0.6480
225
R factors for I > 2σ(I)
R = 0.0258, wR = 0.0676
1
2
for all reflections
R = 0.0342, wR = 0.0718
1 2
Quality for F2
1.088
Extinction coefficient
0.0066(6)
Residual electronic density, min/max, e/Å3
–0.882/0.676
4
3
Table 3. Coordinates of non-hydrogen atoms (×10 ) and their isotropic equivalent thermal parameters U
plex II
(×10 ) for com-
equiv
Atom
x
y
z
Uequiv, Å2
Atom
x
y
z
Uequiv, Å2
Mo
–10163(1) 5883(1)
–10598(1) 4107(1)
–8662(1) 7555(1)
–8016(2) 6422(2)
–7930(2) 4613(2)
–11472(2) 5186(2)
–11441(3) 7085(2)
–5294(3) 4431(3)
–5539(5) 6436(4)
–6478(4) 6103(3)
–2205(1)
–3011(1)
–1487(1)
–2887(1)
–1823(1)
–1654(1)
–2631(1)
–1241(1)
–3510(2)
–2905(1)
28(1)
47(1)
51(1)
37(1)
31(1)
41(1)
44(1)
34(1)
46(1)
31(1)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
C(10)
C(11)
–5379(4)
–6303(3)
–5881(4)
–7392(4)
–7993(4)
–7080(5)
–5537(5)
–4908(4)
–3242(5)
5229(3)
4810(3)
3784(3)
4291(4)
3638(4)
2548(5)
2096(4)
2695(3)
2176(5)
–2339(2)
–1778(1)
–654(1)
–399(2)
156(2)
34(1)
27(1)
32(1)
41(1)
50(1)
55(1)
50(1)
38(1)
54(1)
Cl(1)
Cl(2)
O(1)
O(2)
O(3)
O(4)
N(1)
C(1)
C(2)
457(2)
216(2)
–345(1)
–605(2)
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 26
No. 12
2000

SYNTHESIS AND IR SPECTRAL STUDY
Table 4. Bond lengths and angles in structure II
869
Bond
d, Å
Bond
d, Å
Bond
d, Å
Mo–O(4)
Mo–O(3)
Mo–O(2)
Mo–O(1)
Mo–Cl(1)
Mo–Cl(2)
O(1)–C(2)
1.682(2)
1.685(2)
2.168(2)
2.281(2)
2.336(1)
2.365(1)
1.215(3)
O(2)–C(4)
N(1)–C(4)
N(1)–C(5)
C(1)–C(2)
C(2)–C(3)
C(3)–C(4)
C(5)–C(10)
1.249(3)
1.313(4)
1.432(4)
1.492(4)
1.490(4)
1.496(4)
1.385(4)
C(5)–C(6)
C(6)–C(7)
C(7)–C(8)
C(8)–C(9)
C(9)–C(10)
C(10)–C(11)
1.387(4)
1.384(5)
1.357(5)
1.379(5)
1.382(4)
1.498(5)
Angle
ω, deg
Angle
ω, deg
Angle
ω, deg
O(4)MoO(3)
O(4)MoO(2)
O(3)MoO(2)
O(4)MoO(1)
O(3)MoO(1)
O(2)MoO(1)
O(4)MoCl(1)
O(3)MoCl(1)
O(2)MoCl(1)
O(1)MoCl(1)
O(4)MoCl(2)
O(3)MoCl(2)
104.3(1)
163.03(9)
92.5(1)
O(2)MoCl(2)
O(1)MoCl(2)
Cl(1)MoCl(2)
C(2)O(1)Mo
C(4)O(2)Mo
C(4)N(1)C(5)
O(1)C(2)C(3)
O(1)C(2)C(1)
C(3)C(2)C(1)
C(2)C(3)C(4)
O(2)C(4)N(1)
O(2)C(4)C(3)
80.70(8)
82.99(7)
159.11(4)
135.1(2)
133.2(2)
125.7(2)
124.2(3)
120.3(3)
115.4(3)
117.9(2)
121.4(3)
122.4(2)
N(1)C(4)C(3)
C(10)C(5)C(6)
C(10)C(5)N(1)
C(6)C(5)N(1)
C(7)C(6)C(5)
C(8)C(7)C(6)
C(7)C(8)C(9)
C(8)C(9)C(10)
C(9)C(10)C(5)
C(9)C(10)C(11)
C(5)C(10)C(11)
116.1(2)
121.7(3)
119.4(3)
118.9(3)
118.9(3)
120.3(3)
120.2(3)
121.6(3)
117.2(3)
120.8(3)
122.0(3)
87.6(1)
167.71(9)
75.69(8)
95.81(9)
96.39(8)
84.24(7)
79.30(7)
94.4(1)
98.64(8)
–
1
tomers (~1725, 1710, and 1670–1660 cm ) are shifted uted to the symmetric and asymmetric stretching vibra-
–
1
to the 1690–1680 cm range upon complexation. The tions of the Mo=O bonds of the cis-MoO group [20],
2
–1
intensities and positions of the absorption bands of
skeletal vibrations of the conjugated bond system of the
coordinated acetanilide molecules (1550–1100 cm
range) become changed also.
as well as a new intensive band in the 458–415 cm
range, which can be attributed to the stretching vibra-
tions of the Mo O=C (ligand) bond.
Therefore, with a view to the results of the elemental
–
1
One should notice, in the low-frequency region, two analysis and IR spectral study and the data obtained [1,
intensive bands at 950–945 and 920–915 cm attrib- 3, 18–20], one can suggest that acetoacetanilides react
–1
1
2
*
*
*
*
3
600 3300 3000 1800 1500 1200
900
600 ν, cm–1
Fig. 1. IR spectra of (1) acetoacet-2-toluidine and (2) its complex with MoO Cl (absorption bands of mineral oil are marked with
2
2
asterisks).
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 26
No. 12 2000

8
70
ABRAMENKO et al.
O(4)
O(3)
Cl(1)
Mo
Cl(2)
C(7)
O(1)
O(2)
C(6)
C(5)
C(8)
C(2)
C(4)
C(3)
N(1)
C(1)
C(9)
C(10)
C(11)
Fig. 2. Molecular structure of complex II.
with molybdenum dioxodichloride like β-diketones [4] the O(1)–C(2) bond (1.215(3) Å). The average Mo–
to yield equimolecular adducts with octahedral struc- Cl(1, 2) bond length is 2.350(1) ± 0.001 Å.
ture, in which the neutral ligand molecules are coordi-
nated by two carbonyl oxygen atoms of the diketone
tautomeric form A.
The coordination polyhedron of the Mo atom in
structure II exhibits distortions typical of the dioxo
0
complexes of d -metals of Groups V–VII. As a result of
This suggestion is confirmed by the results of the X- the repulsion of the electronic clouds of the multiple-
ray diffraction analysis of complex II. In this complex bonded oxoligands, the O(3)MoO(4) angle increases to
(Fig. 2), the Mo atom is coordinated by two O(3,4) 104.3(1)° as compared to the standard value of 90° and
oxoatoms in cis-position relative to each other, two the opposite O(1)MoO(2) angle decreases to 75.69(8)°.
Cl(1,2) chlorine atoms in trans-position, and two The trans-angles Cl(1)MoCl(2) 159.11(4)° and
O(1,2) oxygen atoms in trans-positions to the O(3,4) O(oxo)MoO(HL) 165.37(9) ± 2.34° (average) also
atoms. This geometry of the metal coordination polyhe- deviate notably from the value of 180° in a standard
dron conforms to the self-consistency rule [21], which octahedron. The Mo atom is shifted from the center of
states that trans-positions to the multiple-bonded the MoO Cl octahedron toward the O(3)–O(4) edge by
4
2
ligands are preferably occupied by the neutral donor 0.390 Å.
ligands (or ligand atoms) rather than by the acido
Upon coordination of the metal by the HL bidentate
ligand, the six-membered ring
ligands.
The average Mo=O(oxo) bond length in structure II
1.684(2) ± 0.002 Å) is comparable to the average
Mo–O(1)–C(2)–C(3)–C(4)–O(2) closes in the sofa
conformation with a deviation of 0.415 Å of the O(2)
atom from the plane of the other five atoms, coplanar
within ±(0.001–0.064) Å (average 0.036 Å).
(
Mo=O bond length for 162 structures of the Mo(VI)
dioxo complexes (1.704 ± 0.028 Å) [22]. The Mo–
O(HL) bond lengths in II (Mo–O(2) 2.168(2) Å and
Mo–O(1) 2.281(2) Å) vary within the standard range of
As was mentioned above, the low quality of the
the Mo–Otrans distances (2.11–2.38 Å [23]). These crystals of acetoacet-2-toluidine V did not allow a full
bonds are notably elongated in comparison with stan- X-ray diffraction study. Earlier [24], the crystal struc-
dard values (Mo–O 1.94–2.08 Å [23]), due to the trans- ture of the unsubstituted analog of V, i.e., the N-phenyl
effect of the multiple-bonded oxoligand. It is notewor- amide of the acetoacetic acid (VI), was determined. If
thy that the Mo–Otrans bond lengths in structure II are we assume that the conformations of molecules V and
different: the Mo–O(1) bond, adjacent to the CMe VI are similar, then one can conclude that the configu-
group, is 0.113 Å longer than the Mo–O(2) bond join- ration of the initial HL molecule somewhat changes
ing the CN(H)C H Me fragment. The C=O bond during coordination to metal and closure of the six-
6
4
lengths are also unequal. Due to partial delocalization membered metal cycle. The angles between the planar
of the electronic density over the amide fragment, the fragments C(5)–C(10) and N(1), C(3,4), O(2) in com-
O(2)–C(4) bond (1.249(3) Å) adjacent to the N(1)– plex II are only slightly changed in comparison with a
C(4) multiple bond (1.313(4) Å) is 0.034 Å shorter than free molecule (41.8° for II and 33.2°, 39.0° for two
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 26
No. 12
2000

SYNTHESIS AND IR SPECTRAL STUDY
871
independent molecules VI, respectively), whereas the
angles between the fragments N(1), C(3,4), O(2) and
C(1,3), O(1) in structures II and VI are quite different
9. Abramenko, V.L., Sergienko, V.S., Garnovskii,A.D., and
Porai-Koshits, M.A., Koord. Khim., 1987, vol. 13,
no. 12, p. 1695.
1
0. Jones, D., Roberts, A., Cavell, K., et al., J. Chem. Soc.,
Dalton Trans., 1998, no. 2, p. 255.
(21.8° and 97.6°, 84.1°, respectively). The characteris-
tic torsion angles C(4)N(1)C(5)C(10) (138.8° in II and
3
1
1.4°, 39.7° in VI), C(4)N(1)C(5)C(6) (–42.7° in II and 11. Abramenko, V.L. and Garnovskii, A.D., Koord. Khim.,
1
988, vol. 14, no. 6, p. 783.
56.5°, –145.1° in VI), and N(1)C(4)C(3)C(2)
(
−169.4° in II and 101.2°, –95.0° in VI) also differ 12. Maurya, R.C., Mishra, D.D., and Pillai, S., Synth. React.
Inorg. Met.-Org. Chem., 1997, vol. 27, no. 10, p. 1453.
notably.
1
1
3. Maurya, R.C., Mishra, D.D., Pillai, S., and Singh, H.,
Natl. Acad. Sci. Lett. (India), 1998, vol. 21, nos. 1–2,
p. 24.
4. Busev, A.I., Analiticheskaya khimiya molibdena (Ana-
lytical Chemistry of Molybdenum), Moscow: Akad.
Nauk SSSR, 1962.
Structure II contains no intermolecular contacts that
are less than the sums of the van der Waals radii of the
corresponding atoms.
REFERENCES
1
1
1
5. Harms, K., XCAD4. Program for the Lp-Correction of
1
2
3
. Yakimovich, S.I. and Zelenin, K.N., Zh. Obshch. Khim.,
Nonius CAD4 Data, Marburg, Germany, 1997.
1
995, vol. 65, no. 5, p. 705.
6. Sheldrick, G.M., Acta. Crystallogr., Sect. A: Found.
Crystallogr., 1990, vol. 46, no. 6, p. 467.
7. Sheldrick, G.M., SHELXL93. Program for the Refine-
ment of Crystal Structures, Univ. of Göttingen, Ger-
many, 1993.
. Garnovskii, A.D., Nivorozhkin, A.L., and Minkin, V.I.,
Coord. Chem. Rev., 1993, vol. 126, nos. 1–2, p. 1.
. β-Diketonaty metallov. Sbornik nauchnykh trudov
(
Metal β-Diketonates. Collection of Works), Vladivos-
tok: Dal’nevostochn. Univ., 1990, vol. 1.
1
1
2
2
2
8. Nakamoto, K., Infrared Spectra of Inorganic and Coor-
4
5
. Kraus, H.-L. and Huber, W., Chem. Ber., 1961, vol. 94,
dination Compounds, New York: Wiley, 1988.
p. 2864.
^
^
^
^
^
9. Sergienko, V.S., Abramenko, V.L., and Ilyukhin, A.B.,
. Kojic-Prodic, B., Ruzic-Toros , Z., Grdenic, D., and
^
Zh. Neorg. Khim., 1997, vol. 42, no. 6, p. 945.
Golic, L., Acta Crystallogr., Sect. B: Struct. Crystallogr.
Cryst. Chem., 1974, vol. 30, no. 2, p. 300.
0. Abramenko, V.L., Garnovskii,A.D., and Sergienko, V.S.,
Koord. Khim., 1989, vol. 15, no. 12, p. 1587.
6
7
8
. Shkol’nikova, L.M. and Porai-Koshits, M.A., Itogi
1. Shustorovich, E.M., Porai-Koshits, M.A., and Busla-
Nauki Tekh., Ser.: Kristallokhim., Moscow: VINITI,
ev, Yu.A., Coord. Chem. Rev., 1975, vol. 17, no. 1, p. 1.
1
982, vol. 16, p. 117.
2. Mayer, J.M., Inorg. Chem., 1988, vol. 27, no. 22,
. Bhattacharyaya, S., Dutta, S.K., Chaudhury, M., and
Tiekink, E.R.T., Z. Kristallogr., 1998, vol. 213, nos. 7–8,
p. 436.
p. 3899.
23. Porai-Koshits, M.A. and Sergienko, V.S., Usp. Khim.,
990, vol. 59, no. 1, p. 86.
1
. Sergienko, V.S., Abramenko, V.L., Garnovskii, A.D., and
Porai-Koshits, M.A., Koord. Khim., 1985, vol. 11, 24. Sergienko, V.S. and Ilyukhin, A.B., Kristallografiya,
no. 10, p. 1407.
1997, vol. 42, no. 1, p. 171.
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 26
No. 12 2000