Novel tetranuclear cubane-like Co(II) complexes involving chelate phosphoramide ligands

Article abstract of DOI:10.1016/S0277-5387(02)00895-1

Interaction of cobalt(II) ions and sodium carbacylamidophosphates Na(L) (HL = PhC(O)NHP(O)(NR₂)₂; where NR₂ are morpholyl, HL¹; NMe₂, HL²; NEt₂, HL³) in methanol solution afforded polynuclear alkoxo complexes [Co₄{L¹}₃(OCH₃)₄ (OH)(H₂O)₅·3H₂O] 1 and [Co₄{L}₄(OCH₃)₄ (CH₃OH)₄] (L = L², L³ 3). Data of spectral and TGA studies are presented. Coordination compounds 1 and 3 have been characterized by means of X-ray diffraction. Both the structures consist of tetranuclear cubane alkoxo clusters with methoxide ions bridging three metal centers (Co-O 2.068(3)-2.093(4) A?) and phosphorylic ligands coordinated in a bidentatechelate fashion via the carbonyl oxygen atoms (Co-O 1: 2.050(2); 3: 2.031(4) A?) and the phosphoryl groups (2.093(2) and 2.106(4) A?). Isolation of these cubane alkoxo complexes is an important proof for close resemblance in behavior of carbacylamidophosphate systems and β-diketonates towards transition metal ions.

Full text of DOI:10.1016/S0277-5387(02)00895-1

Polyhedron 21 (2002) 963ꢁ967
/
www.elsevier.com/locate/poly
Novel tetranuclear cubane-like Co(II) complexes involving chelate
phosphoramide ligands
Kateryna E. Gubina a,*, Vladimir A. Ovchynnikov a, Jolanta Swiatek-Kozlowska b,
Vladimir M. Amirkhanov a, Tatyana Yu. Sliva a, Konstantin V. Domasevitch a
a Department of Inorganic Chemistry, Kiev University, Vladimirskaya St. 64, Kiev 01033, Ukraine
b Department of Basic Medical Sciences, Medical Academy, Kochanowskiego 14, 51601 Wroclaw, Poland
Received 31 October 2001; accepted 10 December 2001
Abstract
Interaction of cobalt(II) ions and sodium carbacylamidophosphates Na(L) (HLꢀ
morpholyl, HL1; NMe2, HL2; NEt2, HL3) in methanol solution afforded polynuclear alkoxo complexes
[Co4{L1}3(OCH3)4(OH)(H2O)5× L2 2, L3 3). Data of spectral and TGA studies
3H2O] 1 and [Co4{L}4(OCH3)4(CH3OH)4] (Lꢀ
are presented. Coordination compounds 1 and 3 have been characterized by means of X-ray diffraction. Both the structures consist
/PhC(O)NHP(O)(NR2)2; where NR2 are
/
/
˚
of tetranuclear cubane alkoxo clusters with methoxide ions bridging three metal centers (Coꢀ
/
O 2.068(3)ꢁ2.093(4) A) and
/
˚
phosphorylic ligands coordinated in a bidentatechelate fashion via the carbonyl oxygen atoms (CoꢀO 1: 2.050(2); 3: 2.031(4) A) and
/
˚
the phosphoryl groups (2.093(2) and 2.106(4) A). Isolation of these cubane alkoxo complexes is an important proof for close
resemblance in behavior of carbacylamidophosphate systems and b-diketonates towards transition metal ions. # 2002 Elsevier
Science Ltd. All rights reserved.
Keywords: Cobalt(II); Cubane complexes; Carbacylamidophosphates; X-ray data
1. Introduction
cubane complexes in solution is competitive for Co(II)
complexes just as for Co(III).The cubane structure is
also common in the realm of metal diketonates, recent
examples include series of cobalt(II) and nickel (II)
The cubane-like structure of tetranuclear metal com-
plexes is a characteristic motif in coordination chemistry
of different metal ions. It may dominate assembly of
relatively simple compounds like thallium alkoxides [1]
as well as of complicated molecular and supramolecular
architectures [2]. This structural motif with close spatial
alignment of metal centers is important also in the
chemistry of transition metals where it may have an
essential impact considering possible magnetic and
catalytical properties of the compounds [3,4]. The
structural and magnetochemical features of numerous
Co(II) and Co(III) based cubane molecules have been
compounds [8ꢁ11]. We were interested in the generation
/
of the cubane structure for new transition metal
derivatives involving structural analogs of b-diketones.
Such species may allow further functionalization of the
metal-organic core, and phosphazo analogs of b-dike-
tones are of special interest in this context: these N-
acylated phosphoramides bear a close structural resem-
blance to the b-diketone frame, they usually act as
effective chelating groups, and stoichiometry, structure
and properties of coordination compounds thereof may
be clearly related with known types of metal diketo-
nates.
reported [5ꢁ7]. Forming the complete or incomplete
/
In this contribution we report on the engineering of a
tetrameric cubane structure involving Co(II) ions and
three chelating phosphoramide ligands.
* Corresponding author. Tel.: ꢂ
07112.
E-mail address: katlig@mail.univ.kiev.ua (K.E. Gubina).
/
380-4422-10292; fax: ꢂ380-5031-
/
0277-5387/02/$ - see front matter # 2002 Elsevier Science Ltd. All rights reserved.
PII: S 0 2 7 7 - 5 3 8 7 ( 0 2 ) 0 0 8 9 5 - 1

964
K.E. Gubina et al. / Polyhedron 21 (2002) 963ꢁ967
/
2. Experimental
C52H96N12Co4O16P4: C 41.40, H 6.38, N 11.16%.
Anal. for 3. Found: C 47.01, H 8.6, N 9.3. Calc. for
C68H128N12Co4O16P4: C 47.23, H 8.1, N 9.7%.
2.1. Preparation of Co4L4-n(m3-OCH3)4(OH)n ×
/
mSolv
(SolvꢀH2O or CH3OH)
/
2.2. Methods
Dimorpholido-N-benzoylamidophosphate
HL1,
N,N?-tetramethyl-Nƒ-benzoyltriamido-phosphate HL2
IR spectra of the compounds were recorded on an
N,N?-tetraethyl-Nƒ-benzoyltriamidophosphate
HL3
and their sodium salts were obtained and identified
according to [12,13].
UR-10 spectrometer in the range 400ꢁ
(samples as KBr pellets). Differential thermal analyses
were carried out in the temperature range 20ꢁ500 8C
/
4000 cmꢃ1
/
Coordination compounds of cobalt(II) were synthe-
sized reacting the metal chloride and sodium salts of the
ligands in methanol solution:
using a Q-1500 ‘Quasi’ thermoanalyzer at a heating rate
of 5 8C minꢃ1. Electronic diffuse reflectance spectra
were recorded on a SPECORD M-40 (Carl Zeiss, Jena)
UVꢁVis spectrometer.
/
4CoCl2 × 6H2Oꢂ8NaL
CH3OH
X-ray diffraction data for 1 were collected using an
Enraf-Nonius CAD-4 diffractometer. For 3 crystallo-
graphic measurements were made using a SMART CCD
area-detector diffractometer (Siemens). Table 2 lists the
cell parameters and details of data acquisition and
structure refinement. Selected geometrical parameters
of 1 and 3 are listed in Table 3. The structures were
solved by direct methods and refined by full-matrix
least-square methods using programs SHELXS-86 and
SHELXL-93 [14,15]. All the non-hydrogen atoms were
refined anisotropically. The hydrogen atoms were loca-
lized by difference Fourier techniques without further
refinement.
0 Co4L4ꢃn(m3OCH3)4(OH)n × mSolvꢂ4HL
ꢃNaCl
where Lꢃ ꢀ
In a typical synthesis, CoCl2×
/
(L1)ꢃ, (L2)ꢃ, (L3)ꢃ.
6H2O (0.238 g, 1 mmol)
/
was dissolved in methanol (15 ml) and combined with
the solution of NaL1 (0.722 g, 2 mmol) in 10 ml
methanol. The mixture was allowed to stand in a
vacuum desiccator over CaCl2. After a while the pink-
violet crystals of the complex [Co4{L1}3(OCH3)4(OH)-
(H2O)5×
/
3H2O] 1 precipitated from the solution in the
mixture along with neutral ligand HL1. The latter was
separated out by washing the product with methanol
and identified according to IR spectra. Crystals of the
complex were additionally washed with cool acetone,
and dried over CaCl2 (yield: 0.248 g, 65.6%). Complexes
Table 1
Main IR absorption bands and their assignments for carbacylamido-
phosphate compounds, cmꢃ1
[Co4{L}4(OCH3)4(CH3OH)4] (Lꢀ
L2 2, L3 3) were
/
prepared in the same manner. Single crystals of 1 and
3 were prepared by slow crystallization from acetone-
methanol mixture.
The complexes are unstable in air and decompose
under long-term storage. They were soluble in nonpolar
aprotic solvents, less soluble in acetone, isopropanol and
ethyl alcohol.
Compound
n(NH) n(Cꢁ
/
n(Cꢀ
/
n(Pꢁ
/
O)
N)
O)
HL1
NaL1
3100
1685
1545
1530
1440
1385
1380
1200
1115
1110
[Co4{L1}3(OCH3)4(OH)(H2O)5×
3H2O]
/
HL2
NaL2
3070
3070
1680
1595
1535
1675
1535
1530
1460
1380
1380
1450
1380
1380
1280
1130
1085
1280
1120
1090
The compositions of the compounds were established
on the basis of the elemental analysis. Anal. for 1.
[Co4{L2}4(OCH3)4(CH3OH)4]
HL3
NaL3
Found:
C
37.53,
H
5.56,
N
7.75. Calc. for
[Co4{L3}4(OCH3)4(CH3OH)4]
C49H92N9Co4O28P3: C 38.32, H 5.8, N 8.2%. Anal. for
2. Found: C 41.67, H 6.78, N 10.01. Calc. for

K.E. Gubina et al. / Polyhedron 21 (2002) 963ꢁ
/967
965
Table 2
Crystal data and structure refinement for 1 and 3
Table 3
Selected bond lengths (A) and angles (8) for 1 and 3
˚
1
3
1
3
Empirical formula
Temperature (K)
˚
Wavelength (A)
C
293
49H92Co4N9O25P3 C68H128Co4N12O16P4
Bond lengths
223
0.71073
tetragonal
Co(1)ꢀ
Co(1)ꢀ
Co(1)ꢀ
Co(1)ꢀ
Co(1)ꢀ
Co(1)ꢀ
/
O(2)
O(7)a
O(6)
O(7)
O(l)
2.050(2)
2.083(2)
2.086(2)
2.092(2)
2.093(2)
2.161(2)
Co(1)ꢀ
Co(1)ꢀ
Co(1)ꢀ
Co(1)ꢀ
Co(1)ꢀ
Co(1)ꢀ
/
O(2)
O(3)a
O(3)b
O(3)
O(1)
O(4)
2.031(4)
0.71073
rhombohedral
/
/
2.068(3)
2.084(3)
2.091(4)
2.106(4)
2.204(4)
Crystal system
Space group
/
/
R/3/
P/
4
/
21c
/
/
/
/
Unit cell dimensions
˚
/
O(5)
/
a (A)
21.604(3)
26.014(5)
10515(3)
6
16.921(2)
15.404(3)
4410.5(11)
2
˚
c (A)
Bond angles
3
V (A )
˚
P(1)ꢀ
P(1)ꢀ
O(2)ꢀ
N(1)ꢀ
O(2)ꢀ
O(7)aꢀ
O(2)ꢀCo(1)ꢀ
O(2)ꢀCo(1)ꢀ
O(7)aꢀ
O(7)aꢀ
O(1)ꢀCo(1)ꢀ
O(1)ꢀP(1)ꢀN(1)
C(1)ꢀN(1)ꢀP(1)
Co(1)bꢀ
O(7)ꢀCo(1)
/O(l)
1.509(2) P(1)ꢀ
1.617(3) P(1)ꢀ
1.266(4) O(2)ꢀ
1.314(5) N(1)ꢀ
90.47(8) O(2)ꢀ
83.16(9) O(2)ꢀ
93.00(8) O(2)ꢀ
91.55(9) O(3)aꢀ
173.61(8) O(2)ꢀCo(1)ꢀ
89.13(8) O(3)aꢀ
Co(1)ꢀ
96.80(8) O(3)bꢀ
118.37(14) O(3)ꢀCo(1)ꢀ
127.7(2) Co(1)ꢀ
O(2)ꢀ
96.46(9) O(3)aꢀ
Co(1)ꢀ
O(3)ꢀCo(1)ꢀ
O(1)ꢀCo(1)ꢀ
O(1)ꢀP(1)ꢀ
C(1)ꢀN(1)ꢀ
Co(1)cꢀ
O(3)ꢀ
Co(1)cꢀ
O(3)ꢀ
Co(1)bꢀ
O(3)ꢀ
/
O(1)
N(1)
C(1)
C(1)
Co(1)ꢀ
Co(1)ꢀ
Co(1)ꢀ
Co(1)ꢀ
O(1)
O(1)
1.523(4)
Z
/N(1)
/
1.625(5)
1.264(7)
1.294(7)
176.23(14)
93.55(14)
98.1(2)
Crystal size (mm)
2umax (8)
Reflections collected
0.25ꢄ
/
0.25ꢄ
/
0.30 0.2ꢄ/0.2ꢄ/0.25
/
C(1)
C(1)
Co(1)ꢀ
Co(1)ꢀ
/
50.1
5178
3449
2488
51.4
/
/
16341
4059
2490
/
/
O(7)a
O(6)
/
/
O(3)a
O(3)b
O(3)
Independent reflections
/
/
/
/
Reflections observed (ꢀ
/
/
/O(7)
/
/
2s)
Data used/parameters
refined
/
/O(1)
/
/
O(3)
82.73(14)
89.9(2)
3449/271
4059/266
1.050
/
Co(1)ꢀ
/O(1)
/
/
/
Co(1)ꢀ
/O(5)
/
/
93.76(15)
175.09(13)
94.06(14)
93.1(2)
Goodness-of-fit on F2
Rl, wR2 (observed)
Rl, wR2 (all data)
Largest difference peak
0.998
0.037, 0.090
0.068, 0.101
/
/O(5)
/
Co(1)ꢀ
/
O(1)
O(1)
O(4)
0.057, 0.106
0.121, 0.142
/
/
/
/
/
/
/
/
0.52, ꢃ
/0.39
0.48, ꢃ
/
0.43
/
/
/
/
O(4)
85.58(14)
166.36(13)
93.70(15)
118.7(2)
124.7(4)
96.74(14)
96.52(14)
97.7(2)
ꢃ3
˚
and hole (e A
)
/
/O(4)
/
/O(4)
/
/
N(1)
P(1)
3. Results and discussion
/
/
/
/
Co(1)b
Co(1)
/
/
/
/Co(1)
3.1. Spectroscopy
Symmetry transformations used to generate equivalent atoms for 1:
(a) 1ꢃxꢂy, 1ꢃx, z; (b) 1ꢃy, xꢃy, z; for 3: (a) 1ꢃy, x, ꢃz; (b) 1ꢃ
x, 1ꢃy, z; (c) ꢃy, 1ꢃx, ꢃz.
/
/
/
/
/
/
/
/
The IR spectra of the coordination compounds have a
number of common features (Table 1). The IR bands in
/
/
/
/
the region 3070ꢁ
3100 cmꢃ1, observed in spectra of the
/
3.2. Thermogravimetry
neutral carbacylamidophosphates, may be ascribed to
n(NH) vibrations of the amide protons. These bands are
absent in the spectra of the sodium and cobalt(II)
The thermal behavior of the cobalt complexes 2 and 3
is very similar. According to the TGA data, these
complexes are stable up to 100 8C. In the temperature
carbacylamidophosphates 1ꢁ3, which is evidence for
/
ligand coordination in the deprotonated form. The
spectra reveal significantly lower frequencies of n(PO)
as may be compared with those for the sodium salts
range 100 8Cꢁ290 8C, the thermoanalytical curves
/
indicate two endothermic effects. The first of them
(115 8C) is connected with the elimination of four
molecules of methanol. This relatively elevated tempera-
ture of the methanol molecule removal indirectly
indicates their disposition in the internal coordination
sphere of the metal ions. The other endothermic stage
corresponds to the beginning of the decomposition of
the complex. It takes place at the same temperature for
the both compounds, namely 265 8C. Full decomposi-
tion of the complex is accompanied by its vigorous
exothermic oxidation at 285 8C. It is necessary to note
that a difference in the temperatures of the maximal
onset of the processes is not essential and it is equal to
within 20 8C. This fact shows the important role of the
methanol molecules in the formation of the crystal
lattice of the cobalt complexes 2 and 3. The similar
character of the decomposition of these compounds and
(Dn(PO)ꢀ
/
45 and 30 cmꢃ1 for compounds 2 and 3,
respectively), reflecting coordination via the phosphoryl
oxygen atom [8,9]. In the case of compound 1, the
position of the n(PO) band could not be related
identically. The n(CO) values in spectra of the com-
plexes are shifted to lower frequencies (Dn(CO)ꢀ
/
5ꢁ60
/
cmꢃ1). These facts suggest a bidentate chelate coordina-
tion of the anionic ligands Lꢃ via the oxygen atoms of
phosphoryl and carbonyl groups.
UVꢁ/Vis absorption spectra reflect the octahedral
environment the cobalt(II) ions in 1ꢁ
/
3 [16]. The bands
4T1g are
4
related to the electron transition T1g(P)0
/
observed at 18 000, 19 000 and 21 000 cmꢃ1 for 1, 2
4
and 3, respectively. The transition A2g0
/
4T1g is very
weak and appears as a shoulder.

966
K.E. Gubina et al. / Polyhedron 21 (2002) 963ꢁ967
/
the same temperature interval of thermal effects may
suggest a similarity of their structures.
In the case of complex 1, the TGA results are rather
different. The thermoanalytical curves also reflect two
endothermic effects at 130 and 200 8C, and an exother-
mic one at 335 8C. The first effect is connected with the
elimination of three water molecules from the external
sphere of the complex. The compound decomposes at
200 8C. The fact that the further dehydration of 1 is
accompanied by its decomposition is evidence of the
involvement of the other five water molecules in the
internal coordination sphere and their strong bonding
with the central atoms. The full exothermic decomposi-
tion of the complex takes place at 335 8C.
3.3. Description of the structures
We succeeded in confirming the conclusions about the
structure of the obtained compounds based on IR and
UVꢁVis spectroscopy data by the results of full X-ray
/
analysis of compounds 1 and 3.
The solid-state structure of 3 contains discrete tetra-
meric molecules. [Co4{L3}4(m3-OCH3)4(CH3OH)4], each
octahedral Co(II) ion being bound to three m3-OMeꢃ
ligands, one chelating carbacylphosphortriamide ligand
(L3), and one terminal MeOH ligand. Concerning the
composition of the compound and the results of spectral
and TGA studies, the same structure may also be
ascribed for compound 2. The molecule occupies a
special position on an inversion fourfold axis and has
virtual D2d symmetry.
For both structures, the tetrameric skeletons are
formed by four cobalt atoms and four oxygen atoms
of methoxy groups. The octahedral environment for
each cobalt atom in 3 and for three of four cobalt atoms
in 1 comprises three oxygen atoms of methoxy groups,
carbonylic and phosphoryl oxygen atoms of the chelate
anionic ligands and an oxygen atom of an alcohol
molecule in structure 3 (Fig. 1). The fourth cobalt atom
in structure 1 is situated on a threefold axis and is
connected with three oxygen atoms of methoxy groups,
oxygen atoms of two water molecules and one OHꢃ
group. These hydro and hydroxo ligands are structurally
equivalent and all are related by a threefold axis.
The cubane-like frameworks in the present cases are
Fig. 1. Molecular structure of the cobalt cubane alkoxo complexes: A-
Co4{L1}3(OCH3)4(OH)(H2O)5×
3H2O 1, hydrogen atoms oxamethy-
/
lene linkage of morpholine cycles and two of the three phenyl groups
are omitted; B-Co4{L3}4(OCH3)4(CH3OH)4 3, hydrogen atoms, ethyl
and methyl fragments of the phosphorylic, metoxy and methoxo
ligands are omitted for clarity, and only one of the four chelate frames
is shown. Thermal ellipsoids are at 40% probability level and possible
hydrogen bonding is shown as dotted lines.
1 and the Coꢀ
/
O bond with a coordinated methanol
˚
oxygen atom (2.204(4) A) in the case of compound 3 are
the longest.
The ligand deprotonation leads to the appearance of
slightly distorted, the angles Oꢀ
smaller than 908, while the angles Coꢀ
O(2) bond with the car-
/
Coꢀ
/
O are about 58
p-conjugation in the chelate ring of the compounds,
/
OꢀCo are
/
which may be illustrated by the changes of the bond
˚
O (1: 1.509; 3: 1.523 A)
approximately 978. The Coꢀ
/
lengths. Thus the distances Pꢁ
/
bonyl oxygen atom is the shortest in the cobalt
environment in both structures (1: 2.050(2) and 3:
˚
O (1: 1.266; 3: 1.264 A) both appeared slightly
and Cꢁ
/
longer with respect to those for the non-coordinated
molecules HL1 and HL3 [12,18]. The increase of the
˚
2.031(4) A). The Coꢀ
/
O(CH3) bond lengths are typical
for m2- and m3-OMe groups [17] and are in the range of
˚
bond order for Pꢀ
/
N and Cꢀ
/
N caused by the increase of
˚
0.09 A shortening of
2.068(3)ꢁ
/
2.093(4) A for both structures. The distances
O(l) in 1 and 3,
are 2.093 (2), and 2.106(4) A, respectively. The CoꢀO(4)
the p-bonding leads to the 0.05ꢁ
/
to the phosphoryl oxygen atoms, Coꢀ
/
˚
these bond lengths in the complexes with respect to that
observed for HL1 and HL3. The OPNCO chelate
/
˚
bond with a coordinated water molecule (2.161(2) A) for

K.E. Gubina et al. / Polyhedron 21 (2002) 963ꢁ
/967
967
˚
fragment in both structures are planar to within 0.1 A
and the deviation of the metal atoms from these planes
˚
does not exceed 0.5 A.
Center, CCDC numbers CSD-142056 (1) and CSD-
166804 (3). Copies of this information may be obtained
free of charge from the Director CCDC, 12 Union
Road, Cambridge, CB2 1EZ, UK (fax: ꢂ44-1223-
/
336033; e-mail: deposit@ccdc.cam.ac.uk or www:
http://www.ccdc.cam.ac.uk).
The phosphorus atoms have a distorted tetrahedral
References
environment. The atoms forming the angles O(1)ꢀ
/
P(1)ꢀ
/
N(1) (118.378, 118.78) for both cases have the largest
deviations because they are involved in the p-conjuga-
tion. All the other angles in the 3 are nearly tetrahedral.
For each type of the cubane molecules the OH and O
counterparts are involved in extensive intramolecular
hydrogen bonding. Thus, in 3 each MeOH hydroxy
group forms an hydrogen bond with the phosphoryl
oxygen atom of carbacylphosporamide ligand coordi-
[1] A.F. Wells, Structural Inorganic Chemistry, 5th ed., Clarendon,
Oxford, 1986.
[2] M.D. Clark, M.I. Zaworotko, Chem. Commun. (1991)
1607.
[3] M.A. Banares, L. Dauphin, V. Calvo-Perez, T.P. Fehlner, E.E.
Wolf, J. Catal. 152 (1995) 396.
[4] B.C. Gates, Catalytic Chemistry, Wiley-Interscience, New York,
1992.
[5] K. Dimitrou, J.-S. Sun, K. Folting, G.I. Christou, Inorg. Chem.
34 (1995) 4160.
˚
nated to a neighboring Co ion (OÁ Á ÁO 2.78 A). A similar
[6] R.D. Kohn, M. Haufe, G. Kociok-Kohn, A. Filippou, Inorg.
Chem. 36 (1997) 6064.
pattern of intramolecular hydrogen bonding has also
been observed in other alkoxides cubane complexes
containing Co(II), Co(III) and Ni(II) and coordinated
alcohol molecules [7,19].
[7] T. Ama, M.d.M. Rashid, T. Yonemura, H. Kawaguchi, T. Yasui,
Coord. Chem. Rev. 198 (2000) 101.
[8] V.A. Ovchynnikov, V.M. Amirkhanov, A.A. Kapshuk, T.Y.u.
Sliva, T. Glowiak, H. Kozlowski, Z. Naturforsch., Teil. B 53
(1998) 836.
[9] E.A. Bundya, V.M. Amirkhanov, V.A. Ovchynnikov, V.A.
Trush, K.V. Domasevitch, J. Sieler, V.V. Skopenko, Z. Natur-
forsch., Teil. B 54 (1999) 1033.
4. Conclusions
Isolation of cobalt(II) tetranuclear cubane alkoxo
complexes with carbacylamidophosphates is an impor-
tant proof for close resemblance of behaviour of these
ligand systems and b-diketonates towards transition
metal ions. In the present case, the remarkable stability
of (Co{L})4(OCH3)4 or (Co{L})3(CoOH)(OCH3)4 cores
dominates the pathways of interaction in the system
[10] Q.L. Tuan, J.D. Woollins, Coord. Chem. Rev. 176 (1998) 469.
[11] A.L. Kon’kin, V.G. Shtyrlin, N.G. Zabirov, I.A. Litvinov, A.T.
Gubaidullin, R.R. Garipov, A.V. Aganov, A.V. Zacharov,
Phosphorus, Sulfur Silicon 147 (1999) 449.
[12] K.E. Gubina, V.A. Ovchynnikov, V.M. Amirkhanov, V.V.
Skopenko, O.V. Shishkin, Z. Naturforsch., Teil. B 55 (2000)
495.
[13] G.I. Derkach, V.V. Kruzement-Prichodko, A.V. Kirsanov,
Zhurn. Neorg. Khimii (Russ.) 31 (1961) 2391.
[14] G.M. Sheldrick, SHELXS-86, Acta Crystallogr., Sect. A 46 (1990)
467.
M
2ꢂ ꢃ
to be a most stable and common product. This effective
stabilization of a cubane metalꢁalkoxide cluster with a
carbacylamidophosphate anion may allow the prepara-
tion of novel functionalized condensed metalꢁalkoxide
/
Lꢃ and corresponding cubane molecules appear
/
[15] G.M. Sheldrick, SHELXL-93, In: Program for the Refinment of
Crystal Structures, University of Gottingen, Gottingen, Germany,
¨ ¨
/
1993.
[16] J. Reedijk, W.L. Driessen, W.L. Groeneveld, Rec. Trav. Chim.
Pays-Bas. 88 (1969) 1095.
complexes.
[17] C. Goh, B.M. Segal, J. Huang, J.R. Long, R.H. Holm, J. Am.
Chem. Soc. 118 (1996) 11844.
5. Supplementary material
[18] V.M. Amirkhanov, V.A. Ovchynnikov, T. Glowiak, H.Z. Ko-
zlowski, Z. Naturforsch., Teil. B 52 (1997) 1331.
[19] M. Halcrow, J.S. Sun, J.C. Huffman, G. Christou, Inorg. Chem.
34 (1995) 4167.
Crystallographic data for the structural analysis have
been deposited at the Cambridge Crystallographic Data