Complexation of N-alkyl(aryl)- and N,N-dialkylcarbamoylmethylphosphine oxides with the f-elements

Article abstract of DOI:10.1007/s11172-008-0255-9

Complexation of N-alkyl(aryl)carbamoylmethylphosphine oxides (CMPO) and their N, N-dialkyl analogs in neutral media was studied. N-Alkyl derivatives react with praseodymium and europium nitrates both in solution and in the individual state to give 1: 2 an

Full text of DOI:10.1007/s11172-008-0255-9

Russian Chemical Bulletin, International Edition, Vol. 57, No. 9, pp. 1890—1896, September, 2008
1890
Complexation of Nꢀalkyl(aryl)ꢀ and
N,Nꢀdialkylcarbamoylmethylphosphine oxides with the fꢀelements
E. V. Sharova, O. I. Artyushin, Yu. V. Nelyubina, K. A. Lyssenko, M. P. Passechnik, and I. L. Odinets
A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences,
28 ul. Vavilova, 119991 Moscow, Russian Federation.
Fax: +7 (499) 135 5085. Eꢀmail: odinets@ineos.ac.ru
Complexation of Nꢀalkyl(aryl)carbamoylmethylphosphine oxides (CMPO) and their
N,Nꢀdialkyl analogs in neutral media was studied. NꢀAlkyl derivatives react with praseodymium
and europium nitrates both in solution and in the individual state to give 1 : 2 and 1 : 3 complexꢀ
es, depending on the ratio of the starting reagents; for Nꢀaryl amides, 1 : 3 complexes were
obtained only. With the uranyl cation, both Nꢀalkyl and N,Nꢀdialkyl derivatives of CMPO form
various 1 : 1 complexes.
Key words: complexation, carbamoylmethylphosphine oxides, actinides, lanthanides.
Phosphorylacetamides, which are also referred to as
For benzylꢀmodified Nꢀalkyl(aryl)carbamoylmethylꢀ
phosphine oxides (CMPO), the complexes La(L´)2(NO3)3,
carbamoylmethylphosphoryl compounds, are neutral orꢀ
ganophosphorus complexing agents used in disposal of liqꢀ
uid radioactive wastes.1—4 Although complexes obtained in
model experiments in neutral media often differ from comꢀ
plexes produced in an organic phase during real extraction
from acidic media, it is obvious that the design of more
efficient extractants is impossible without an insight into
the fundamental coordination chemistry of ligands emꢀ
ployed in extraction systems. For this reason, the strucꢀ
tures of fꢀelement complexes with known carbamoylmeꢀ
thylphosphoryl compounds have been examined by a numꢀ
ber of researchers.5—13
For instance, in the study of the complexation between
the phosphonates (RO)2P(O)CH2C(O)NEt2 (L, R = Et
and Pri) and fꢀelements, the complexes UO2(L)(NO3)2,6
Th(L)2(NO3)4,7 Ln(L)2(NO3)3 (Ln = La—Gd),8 and
Ln(L)2(NO3)3•H2O (Ln = Tb—Eu)8 were isolated and
characterized by spectroscopic methods or, in a number of
cases, by a singleꢀcrystal Xꢀray diffraction. In the complexꢀ
es of the first three types, the ligand is coordinated
via O,Oꢀbidentate fashion, while in the last type, the Ln
atom is coordinated to the ligand through the phosphoryl
O atom and the carbonyl O atom is hydrogenꢀbonded to
the water molecule coordinated by the metal atom.8 Acꢀ
cording to Xꢀray diffraction data, N,Nꢀdimethyldiethoxyꢀ
phosphorylacetamide (L = (EtO)2P(O)CH2C(O)NMe2)
also forms the lanthanide complexes Ln(L)2(NO3)3
(Ln = La, Sm, Yb, Er, Ce, Eu, and Gd) with bidentate
coordination of the O atoms of the phosphoryl and carboꢀ
nyl groups.9 Complexes of the uranyl cation with this ligand
and its diphenylphosphoryl analog have a similar structure
and a metalꢀtoꢀligand ratio of 1 : 1 (UO2(L)(NO3)2).10
Er(L´)2(NO3)3•H2O,
UO2(L´)(NO3)2,
and
UO2(L´)2(NO3)2 (L´ = (PriO)2P(O)CH(CH2Ar)CONEt2
and Ph2P(O)CH(CH2Ar)CONEt2)11,12 were obtained.
According to IR and NMR spectra and singleꢀcrystal Xꢀray
diffraction data, the ligands in these complexes also show
bidentate O,Oꢀcoordination.
Thus, under neutral conditions, N,Nꢀdialkylcarbamꢀ
oylmethylphosphoryl compounds mainly yield ML comꢀ
plexes with a metalꢀtoꢀligand ratio of 1 : 1 or sometimes
1 : 2 for the uranyl cation and 1 : 2 for other lanthanides.
Complexes of fꢀelements (thorium, lanthanum, cerium,
neodymium, europium, and ytterbium) with a ratio of 1 : 3
were obtained and, in some cases, structurally characꢀ
terized only for the ligand containing three CMPO fragꢀ
ments fixed on the C3ꢀsymmetrical triphenoxymethane
platform.13
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1856—1862, September, 2008.
1066ꢀ5285/08/5709ꢀ1890 © 2008 Springer Science+Business Media, Inc.

Complexes of carbamoylmethylphosphine oxides
Russ.Chem.Bull., Int.Ed., Vol. 57, No. 9, September, 2008
1891
Recently, we have developed efficient methods for the
synthesis of Nꢀ(C2—C12)alkylꢀ and Nꢀarylcarbamoylꢀ
methylphosphine oxides14 of the general formula
Ph2P(O)CH2C(O)NHR (R = Alk, Ar, (CH2)nAr, and
(CH2)nHet; n = 1 and 2). The corresponding Nꢀalkyl derivꢀ
atives are virtually as efficient in the extraction of transuraꢀ
nium elements from nitric acid media as their N,Nꢀdialkyl
analogs used in practice, but Nꢀalkyl derivatives are subꢀ
stantially easier to prepare.
Since the presence of the hydrogen atom at the N atom
makes the CMPO molecule more hydrophilic and can
change the character of its complexation with actinide
atoms, here we studied the coordination of fꢀelements with
the ligands NH(Alk)ꢀ and NH(Ar)ꢀCMPO in neutral meꢀ
dia and compared their coordination behavior with that of
the corresponding N,Nꢀdialkyl analogs.
and 3, depending on the ratio of the starting reagents) the
reaction mixtures. The chemical shifts in the 31P NMR
spectra (CD3OD) of complexes 1a—d isolated in the indiꢀ
vidual state (Table 2) are similar to those for the reaction
mixtures (Table 3). The IR spectra of solidꢀstate praseodyꢀ
mium complexes 1a and 1b with metalꢀtoꢀligand ratios of
1 : 2 and 1 : 3, respectively, exhibit no absorption bands
characteristic of the free P=O and C=O groups (in the
spectrum of the solidꢀstate free ligand L1, they appear at
1178 and 1663 cm–1, respectively). Instead, the spectrum
contains bands at 1161 (1a) and 1162 cm–1 (1b) (coordiꢀ
nated P=O group) and at 1627 cm–1 (coordinated C=O
group). The nitrate groups coordinated in a bidentate manꢀ
ner absorb at 1470 (ν(N=O)), 1317 (νas(NO2)), and
1029 cm–1 (νs(NO2)). The absence of the absorption band
at ~1380 cm–1 (free nitrate group) suggests that all the
nitrate groups in complexes 1a and 1b are coordinated by
the metal in a bidentate fashion (i.e., the coordination
number of praseodymium is 10 and 12, respectively). Note
that the IR spectra of praseodymium complexes 1a,b and
europium complexes 1c,d are similar in the corresponding
pairs. Therefore, europium and praseodymium complexes
are structurally alike.
In the case of the ligand L2, the only complex obtained
as a precipitate from solutions with different molar ratios
of the reagents was Pr(L2)3(NO3)3 (2) (metal : ligand =
= 1 : 3). Samples of complex 2 isolated from the reaction
mixtures with different metalꢀtoꢀligand ratios showed
identical melting points, identical IR and 31P NMR specꢀ
tra, and close elemental analysis data. The presence of
several absorption peaks due to the coordinated carbonyl
(1646, 1635, and 1622 cm–1) and phosphoryl groups (1167
and 1154 cm–1) in the IR spectrum of powdered complex
2 suggests some lack of equivalence among the ligands
coordinated in a O,Oꢀbidentate fashion, while the presꢀ
ence of a lowꢀintensity band at 1397 cm–1 (ν(NO3)) points
to a possible migration of one nitrate group to the outer
coordination sphere.
Results and Discussion
We used (Nꢀisobutylcarbamoylmethyl)diphenylphosꢀ
phine oxide (L1, [Ph2P(O)CH2C(O)NHBui]), diphenylꢀ
(Nꢀphenylcarbamoylmethyl)phosphine oxide (L2,
[Ph2P(O)CH2C(O)NHPh]), and (N,Nꢀdibutylcarbamoylꢀ
methyl)diphenylphosphine
oxide
(L3,
[Ph2P(O)CH2C(O)NBu2]) as model compounds.
Upon mixing of an ethanolic solution of the ligand L1
or L2 with praseodymium or europium nitrates in molar
ligandꢀtoꢀmetal ratios of 2 : 1 and 3 : 1, the 31P NMR specꢀ
tra show singlets appreciably shifted downfield (Pr) or upꢀ
field (Eu) relative to their positions for the free ligand in
the same solvent (δP = 32.54 (L1) and 32.65 (L2)); the
signal of the free ligand is absent (Table 1). Considerable
downfield and upfield shifts of the signals provide convincꢀ
ing evidence for the participation of the phosphine oxide
group in the coordination.
In the case of the ligand L1, precipitate with time from
the complexes M(L1)x(NO3)3 1a—d (M = Pr and Eu; x = 2
Indeed, according to singleꢀcrystal Xꢀray diffraction
data for complex 2 (Fig. 1, Table 4), three ligand moleꢀ
cules are coordinated to the Pr atom through the O atoms
of all phosphoryl and carbonyl groups. At the same time,
three nitrate groups show different ways of coordination:
bidentate for one group and monodentate for the second,
while the third is in the outer coordination sphere and is
strongly hydrogenꢀbonded to the NH group of one ligand
(O...N, 2.886(2) Å). Thus, the coordination number of
praseodymium is nine and its coordination polyhedron is a
distorted monocapped antiprism. The Pr—O distances
range from 2.421(2) to 2.625(2) Å. The bonds between the
metal atom and the phosphoryl O atom are the strongest
ones, while the bonds between the metal atom and the
nitrate O atoms are the weakest ones. It should be noted
that the Pr—O bond lengths for the O atoms of the C=O
and P=O groups of each ligand differ substantially. The
Table 1. 31P NMR spectra (EtOH, δ) of the reaction mixꢀ
tures with different molar ligandꢀtoꢀmetal ratios (complexes
Ln(L)n(NO3)3, where Ln = Pr and Eu and L = L1—L3)
Ligand Metal
2 : 1
3 : 1
δ
Δδ
δ
Δδ
Р
Р
L1
Pr
Eu
U
Pr
Pr
Eu
75.25
–13.68
44.66
77.45
73.76
42.71
65.39
–6.56
44.08
67.53a
32.85
39.10
11.54
34.88
—
–46.22
12.12
44.8
42.01
42.85 –13.37
L2
L3
b
—
–11.10
45.12
a The spectrum was recorded in EtOH—CH2Cl2 (1 : 1, v/v).
b Mixing of the reagents resulted in the immediate precipitaꢀ
tion of Pr(L3)2(NO3)3.

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Russ.Chem.Bull., Int.Ed., Vol. 57, No. 9, September, 2008
Sharova et al.
Table 2. Yields, physicochemical constants, and elemental analysis data for the complexes M(L)n(NO3)3 (1—5)
Complex M
L
n
Yield*
(%)
M.p./°C
(solvent)
Found
Calculated
Molecular
formula
(%)
C
H
N
1a
1b
1c
1d
2
Pr
Pr
Eu
Eu
Pr
Pr
Eu
U
L1
L1
L1
L1
L2
L3
L3
L1
L1
2
3
2
3
3
2
2
1
1
55
56
58
62
75
71
68
77
55
128—129
(hexane—MeOH)
121—122
(hexane—MeOH)
131—132
(Et2O—MeOH)
109—110
(Et2O—MeOH)
215—216 (EtOH)
45.46
45.15
51.00
50.95
44.68
44.64
50.41
50.51
53.90
54.07
49.41
49.40
48.64
48.89
30.44
30.48
32.92
32.99
4.72
4.63
5.27
5.23
4.60
4.58
5.14
5.18
3.99
4.08
5.64
5.65
5.59
5.59
3.09
3.13
3.40
3.38
7.20
7.31
6.54
6.60
7.04
7.23
6.54
6.55
6.06
6.30
6.44
6.55
6.41
6.48
5.88
5.92
4.46
4.27
C36H44N5O13P2Pr
C54H66N6O15P3Pr
C36H44EuN5O13Р2
C54H66EuN6O15P3
C60H54N6O15P3Pr
C44H60N5O13P2Pr
C44H60EuN5O13Р2
C18H22N2O10PU
C36H44N4O15P2U2
3a
3b
4
167—168
(PriOH)
141—142
(EtOH)
235—237
(EtOH)
215—217
(EtOH)
5
U
* For the recrystallized product.
main geometrical parameters of three ligands in complex 2
are close to each other. In the crystal, the cations of
complex 2 form layers stabilized by the aforementioned
Hꢀbonds to uncoordinated anions and Hꢀbonds to coordiꢀ
nated nitrates (O...N, 2.849(2)—3.227(2) Å).
Reactions of N,Nꢀdibutylcarbamoylmethyldiphenylꢀ
phosphine oxide (L3) with praseodymium and europium
nitrates under analogous conditions (EtOH) give the crysꢀ
talline complexes M(L3)2(NO3)3 (M = Pr (3a) and Eu
(3b)), regardless of the ratio of the starting reagents (see
Tables 1 and 2). For L3 : Pr = 3 : 1, ethanolꢀinsoluble
complex 3a precipitates immediately upon mixing of the
reagents. This makes it impossible to accurately record an
31P NMR spectrum of the reaction mixture: in the superꢀ
natant solution, the spectrum shows only a signal for the
unreacted free ligand L3.
Complexes 3a and 3b are isostructural; this follows
from the Xꢀray diffraction data for their solvates with an
ethanol molecule (Fig. 2, Table 5). The bond lengths and bond
angles in the ligand L3 are equal within the experimental
error, while the lengths of the bonds formed by the metal
atoms are different. In complexes 3a,b, the metal atom is
coordinated by two neutral ligands L3 and three nitrate
anions. The latter are coordinated in a bidentate fashion
with a slight asymmetry (the M—O bond lengths in the
nitrate ligands range from 0.03 to 0.05 Å). The coordinaꢀ
tion number of the metal atom in the complex is ten. The
observed shortening of the M—O bonds for the europium
complexes (compared to the praseodymium ones) is conꢀ
sistent with the decrease in the atomic radius of the metal.
The bidentate O,Oꢀcoordination of both ligands is similar
to that described for carbamoylmethylphosphoryl comꢀ
pounds with a different environment of the P or N atom
(see above). The ethanol solvate molecule is weakly hydroꢀ
genꢀbonded (O...O, 3.001(2) Å) to the phosphoryl O(1)
atom, which slightly lengthens the M—O bond (M = Eu).
In the 31P NMR spectra of complexes 3a,b, the singlets
are significantly shifted upfield for M = Eu and downfield
O(5N)
N(2N)
O(6N)
C(2B)
C(9B)
C(9A)
P(1A)
C(3A)
O(7N)
O(8N)
C(3B)
C(1B)
O(1A)
O(3N)
O(4N)
N(3N)
O(9N)
P(1B)
O(1B)
C(1A)
C(2A)
N(1B)
C(15B)
Pr(1)
N(1N)
O(2A)
N(1A)
C(15A)
O(1N)
O(1)
C(9)
O(2)
O(2N)
O(2B)
N(1)
C(2)
P(1)
C(3)
C(15)
C(1)
Fig. 1. General view of the complex Pr(L2)3(NO3)3 (2) (the secꢀ
ondary position for the disordered phenyl group is omitted).

Complexes of carbamoylmethylphosphine oxides
Russ.Chem.Bull., Int.Ed., Vol. 57, No. 9, September, 2008
1893
Table 3. 31P NMR and IR spectra of complexes 1—5
Complex
δ
IR, ν/cm–1
P
(CD3OD)
ν(PO)
ν(CO)
ν(NH) δ(NH) + ν(CN) ν (NO2)
ν (NO2) ν(N=O)
s
as
1a
1b
1c
1d
2
70.65
63.09
–9.06
–1.43
58.59
1161
1162
1162
1162
1167,
1154
1627
1627
1627
1627
1646,
1635,
1622
1598
3300
3267
3292
3262
3291
1566
1569
1568
—
1317
1317
1312
1317
1317,
1305
1029
1029
1029
1029
1397
1472
1468
1470
1469
1450
1564
3a
3b
4*
5*
71.37
–8.13
1171
1155
1172,
1157
1159
1148
1163
—
—
—
—
1320,
1300
1306
1034
1034
1030
1024
1457
1465
1467
1469
1598
1616
1617
44.5 (br)
46.8**
3339
3339
1567
1547
1327,
1300
1319
* ν (O=U=O) = 938 (4), 916, and 895 cm–1 (5).
as
** The spectrum was recorded in MeCN.
for M = Pr. The chemical shifts for complexes 3a,b are
close to those for complexes 1a,c with the ligand L1. The
IR spectra of complexes 3a,b are generally similar to the
spectra of complexes 1a—d formed by an Nꢀisobutyl anaꢀ
log of this ligand. In the spectra of complexes 3a,b, the
absorption band due to the coordinated C=O group is shiftꢀ
ed to the lower frequencies (1598 cm–1) and the band of
the phosphoryl group has two peaks at 1171 (1172) and
1158 (1159) cm–1. These peaks correspond to a molecule
of the ligand L3 in which the P=O group is coordinated
only to the metal atom and another molecule of this ligand
additionally hydrogenꢀbonded to ethanol through the
phosphoryl O atom.
carbonyl groups, while reactions of N,Nꢀdialkylcarbamoylꢀ
methylphosphoryl compounds with the same metals under
similar conditions yield only 1 : 2 complexes. Apparently,
the ability of NHꢀalkyldiphenylphosphorylacetamides to
form stable 1 : 2 and 1 : 3 complexes with lanthanides is
due to the lower steric hindrance in the ligand molecule.
As noted above, when the central methylene unit bears
no additional substituents, N,Nꢀdialkyl derivatives of
CMPO form 1 : 1 complexes with the uranyl cation (see
Refs 6 and 10) via the bidentate O,Oꢀcoordination of the
ligand. Analogously, a reaction of the ligand L1 with
uranyl nitrate in a ratio of 1 : 1 gives the complex
[UO2(L1)(NO3)2] (4). Its structure was confirmed by IR
and Raman spectra, elemental analysis, and singleꢀcrystal
Xꢀray diffraction (Fig. 3, Table 6).
Thus, Nꢀalkyl(aryl)carbamoylmethyldiphenylphosꢀ
phine oxides react with praseodymium and europium niꢀ
trates in neutral media to give both 1 : 2 and 1 : 3 complexꢀ
es with a bidentate coordination of the phosphoryl and
In complex 4, the coordination sphere of the uranium
atom is made up of a neutral molecule of L1 and two
Table 4. Selected bond lengths (d) and bond angles (ω) in structure 2
Bond
d/Å
Bond
d/Å
Angle
ω/deg
P(1)—O(1)
O(2)—C(2)
1.4974(18)
1.236(3)
O(2A)—C(2A)
N(1N)—O(1N)
N(1N)—O(2N)
N(1N)—O(3N)
N(2N)—O(4N)
N(2N)—O(5N)
N(2N)—O(6N)
N(3N)—O(7N)
N(3N)—O(8N)
N(3N)—O(9N)
P(1B)—O(1B)
O(2B)—C(2B)
1.232(3)
1.235(3)
1.254(3)
1.270(3)
1.273(3)
1.255(3)
1.217(3)
1.253(3)
1.259(3)
1.233(3)
1.5067(18)
1.240(3)
P(1)—O(1)—Pr(1)
C(2)—O(2)—Pr(1)
138.20(10)
137.42(16)
136.10(10)
140.01(16)
135.48(10)
135.68(16)
97.06(13)
95.45(13)
136.94(15)
Pr(1)—O(1)
Pr(1)—O(2)
Pr(1)—O(1A)
Pr(1)—O(2A)
Pr(1)—O(1B)
Pr(1)—O(2B)
Pr(1)—O(2N)
Pr(1)—O(3N)
Pr(1)—O(4N)
P(1A)—O(1A)
2.4210(17)
2.5231(17)
2.4532(17)
2.5015(17)
2.4193(16)
2.5533(17)
2.6011(18
2.6259(18)
2.4630(18)
1.4969(18)
P(1A)—O(1A)—Pr(1)
C(2A)—O(2A)—Pr(1)
P(1B)—O(1B)—Pr(1)
C(2B)—O(2B)—Pr(1)
N(1N)—O(2N)—Pr(1)
N(1N)—O(3N)—Pr(1)
N(2N)—O(4N)—Pr(1)

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Russ.Chem.Bull., Int.Ed., Vol. 57, No. 9, September, 2008
Sharova et al.
C(6A)
O(6N)
N(2N)
C(17´)
O(4N)
C(7A)
O(1N)
C(5A)
C(16´)
O(3N)
C(15´)
C(4A)
O(4N)
C(18´)
C(20)
C(22)
C(21)
C(8A)
C(10A)
O(1S)
C(11A)
N(1N)
O(2N)
C(3A) N(2N)
P(1A)
O(1A)
C(17)
C(9A)
O(6N)
O(2)
C(19)
O(5N)
N(1)
C(2)
C(14)
C(1)
C(12A)
C(13A)
U(1)
C(18)
C(13)
C(12)
C(11)
C(1A)
C(2A)
O(2)
N(1)
C(2)
C(16)
C(22A)
C(14A)
O(5N)
O(1)
O(2S)
O(1)
C(14)
C(10)
C(21A)
C(13)
C(12)
C(11)
O(2A)
P(1)
C(3)
C(8)
C(19A)
C(20A)
N(1A)
C(16A)
C(15)
C(9)
C(1)
P(1)
C(3)
O(8N)
O(2N)
O(7N)
N(9N)
C(15A)
N(3N)
C(9)
N(1N)
C(4)
C(7)
C(6)
O(3N)
O(1N)
C(10)
C(8)
C(4)
C(17A)
C(5)
C(18A)
C(5)
Fig. 2. General view of the complex [M(L3)2(NO3)3] (M = Pr
(3a) and Eu (3b)) (the secondary position for the disordered butyl
substituent is omitted).
C(7)
C(6)
Fig. 3. General view of the complex [UO2(L1)(NO3)2] (4).
nitrate anions, all of them acting as bidentate ligands. The
coordination number of uranium in complex 4 is eight and
its coordination polyhedron is a hexagonal bipyramid. The
bond lengths in the phosphorusꢀcontaining ligand are virꢀ
tually equal to those in complexes 2 and 3a,b. The U—O
distances range widely from 1.758(3) Å in the fragment
O=U=O to 2.427 Å for the bond between the uranium
atom and the carbonyl O atom. The uranyl fragment is
slightly asymmetric: the U—O bond lengths are 1.758(3)
and 1.772(3) Å. A similar pattern can be noted for interacꢀ
tions of this cation with one nitrate ion (1N): the differꢀ
ence in the U—O distances amounts to 0.03 Å (see Fig. 3).
The N(1N)—O(3N) bond, which is not involved in the
coordination to uranyl, is substantially shorter (by ~0.1 Å)
than the N(2N)—O(6N) bond of the other nitrate ion.
This fact can be explained by the presence of a sufficiently
short O...O contact (2.957 Å) between the O(1S) atoms of
the uranyl fragment and the O(3N) atoms of a nitrate
anion. This strongest contact gives rise to a centroꢀ
symmetric dimer in the crystal. The dimers are united
into a threeꢀdimensional framework through the weaker
N—H...O, C—H...O, and C—H...C contacts.
For other metalꢀtoꢀligand ratios (1 : 2 and 1 : 3), we
isolated uranium complex 5* with a ratio of 1 : 1. Its strucꢀ
* Samples of complex 5 isolated from different reaction mixtures
show identical melting points, identical IR spectra, and very
close elemental analysis data (to within the experimental error).
Table 6. Selected bond lengths (d) and bond angles (ω) in
structure 4
Table 5. Selected bond lengths (d) for the metal atoms in
structure 3
Parameter
Value
Parameter
Bond
Value
Bond
d/Å
d/Å
U(1)—O(1)
U(1)—O(2)
U(1)—O(1N)
U(1)—O(2N)
U(1)—O(4N)
U(1)—O(5N)
U(1)—O(1S)
U(1)—O(2S)
P(1)—O(1)
O(2)—C(2)
2.350(3) N(1N)—O(1N)
2.427(3) N(2N)—O(6N)
2.521(3) N(2N)—O(5N)
2.493(3) N(2N)—O(4N)
2.536(3)
1.290(5)
1.220(5)
1.260(5)
1.288(5)
Bond
d/Å
Bond
d/Å
Pr(1)—O(1)
Pr(1)—O(2)
2.441(2)
2.508(3)
2.427(3)
2.459(2)
2.595(3)
2.556(3)
2.624(3)
2.633(3)
2.683(3)
2.600(3)
Eu(1)—O(1)
Eu(1)—O(2)
2.391(2)
2.458(2)
2.375(2)
2.416(2)
2.529(3)
2.499(2)
2.578(2)
2.587(2)
2.718(3)
2.523(3)
Pr(1)—O(1A)
Pr(1)—O(2A)
Pr(1)—O(1N)
Pr(1)—O(2N)
Pr(1)—O(4N)
Pr(1)—O(5N)
Pr(1)—O(7N)
Pr(1)—O(8N)
Eu(1)—O(1A)
Eu(1)—O(2A)
Eu(1)—O(1N)
Eu(1)—O(2N)
Eu(1)—O(4N)
Eu(1)—O(5N)
Eu(1)—O(7N)
Eu(1)—O(8N)
2.545(3)
Angle
ω/deg
136.30(19)
135.9(3)
1.758(3) P(1)—O(1)—U(1)
1.772(3) C(2)—O(2)—U(1)
1.512(3) N(1N)—O(1N)—U(1) 95.7(2)
1.259(5) N(1N)—O(2N)—U(1) 97.6(3)
N(1N)—O(3N) 1.212(5) N(2N)—O(4N)—U(1) 97.0(3)
N(1N)—O(2N) 1.268(5) N(2N)—O(5N)—U(1) 97.4(3)

Complexes of carbamoylmethylphosphine oxides
Russ.Chem.Bull., Int.Ed., Vol. 57, No. 9, September, 2008
1895
ture was suggested by the IR and Raman spectra and eleꢀ
mental analysis data.
its νas(O=U=O) frequencies are lower and that the strength
of the uranium—ligand bonds in complex 4 is close to that
in related complexes of CMPO with the phosphate and
phosphinate environment of the P atom.
In the 31P NMR spectra of uranium complexes 4 and 5
of the formula ML, the signals appear at δ 44.5 (CD3OD)
and 46.81 (MeCN), respectively. The IR and Raman specꢀ
tra of complexes 4 and 5 are different. The coordinated
carbonyl group in both complexes absorbs at 1616 (1617)
cm–1. The band due to the coordinated phosphoryl group
shows two peaks at 1159 and 1148 cm–1 for complex 4 and
a peak at 1163 cm–1 for complex 5. The antisymmetric
vibrations of UO2 are manifested as a band at 938 cm–1
for complex 4 and as two bands at 916 and 895 cm–1
for complex 5. Note that the position of the νas(UO2)
band correlates with the length of UO2 and with the elecꢀ
tron densities of the uranyl—ligand bonds.15,16 A strengꢀ
thening of the uranyl—ligand bonds increases the
U=O bond length, which in turn shifts the νas(UO2)
band to the lower frequencies. For the uranyl compꢀ
In the Raman spectra of complex 4, the line
νs(O=U=O) appears at 860 cm–1, while the spectra of
complex 5 show two lines at 831 and 821 cm–1, like two
absorption bands corresponding to νas(O=U=O) in its IR
spectra. Apparently, this splitting is due to the coupled
vibrations of two uranyl groups in the suggested structure.
The vibrations of the U—O—U bridge in complex 5
(i.e., the motion of the O atom between the heavy atoms)
should be manifested in the lowꢀfrequency range of its IR
spectrum. However, their accurate assignment is difficult
because the IR spectra of analogous structures are lacking
in the literature.
To sum up, the difference in the composition and strucꢀ
ture of the fꢀelement complexes with Nꢀalkyl(aryl)ꢀ
carbamoylmethylphosphine oxides and their N,Nꢀdialkyl
analogs is due to the presence of the hydrogen atom at the
N atom in CMPO. The general feature of all complexes is
the bidentate O,Oꢀcoordination of the ligands.
lexes
UO2[Ph(EtO)P(O)CH2C(O)NEt2](NO3)2,10
[UO2[(PriO)2P(O)CH2C(O)NEt2](NO3)2],6
and
UO2[Ph2P(O)CH2C(O)NEt2](NO3)2,10 the ν(O=U=O)
band appears at 943, 930, and 925 cm–1, respectively. This
suggests a monotonic strengthening of the coordination
bonding as phenyl groups are attached to the P atom and is
consistent with the soꢀcalled "anomalous aryl strengthenꢀ
ing effect".17 Taking this into account, one can believe that
the coordination bonds in complex 5 are stronger because
Experimental
The 31P NMR spectra of the reaction mixtures and the inꢀ
dividual complexes were recorded on Bruker Avanceꢀ400
Table 7. Selected crystallographic parameters and the data collection and refinement statistics for complexes 2, 3a, 3b, and 4
Parameter
2
3a
3b
4
Molecular formula
Molecular mass
T/K
C60H54N6O15P3Pr
1332.91
100
C46H66N5O14P2Pr
1115.89
120
C46H66EuN5O14P2
1126.94
120
C18H22N3O10PU
709.39
100
Crystal system
Space group
Triclinic
Pꢀ1
Triclinic
Pꢀ1
Triclinic
Pꢀ1
Triclinic
Pꢀ1
Z
2
2
2
2
a/Å
b/Å
c/Å
α/deg
9.3849(5)
14.9167(7)
22.0521(10)
107.116(5)
96.453(5)
94.641(5)
2910.5(3)
1.521
12.377(3)
12.615(3)
17.989(5)
87.870(5)
82.503(5)
67.810(5)
2578.1(11)
1.437
12.4571(8)
12.5977(8)
17.9578(11)
87.336(6)
82.157(6)
67.522(6)
2579.6(3)
1.451
9.1160(17)
10.2952(19)
14.003(2)
70.343(7)
79.391(5)
67.463(5)
1140.8(3)
2.065
β/deg
γ/deg
V/Å3
dcalc/g cm–3
μ/cm–1
9.94
10.74
13.45
72.43
F(000)
1360
1156
1164
676
2θmax/deg
56
56
56
53
Number of measured reflections
32326
26606
53287
9501
Number of independent reflections
13990
12374
12448
4924
Number of reflections with I > 2σ(I)
11545
10394
9713
4296
Number of parameters refined
761
629
629
300
R1
wR2
GOF
0.0352
0.0746
1.000
0.0524
0.1353
1.007
0.0419
0.1025
1.008
0.0280
0.0623
1.001
Residual electron density
1.328/–0.795
2.422/–0.917
1.543/–0.851
1.701/–0.683
/e•Å–3, ρmin/ρ
max

1896
Russ.Chem.Bull., Int.Ed., Vol. 57, No. 9, September, 2008
Sharova et al.
(161.98 MHz) and Bruker Avanceꢀ300 instruments (121.49 MHz)
with 85% H3PO4 as the external standard. The IR spectra were
recorded on a MagnaꢀIR 750 FTIR spectrometer (Nicolet) (resꢀ
olution 2 cm–1, number of scans 128, KBr pellets or Nujol). The
Raman spectra of powdered complexes were measured on a Jobin
Yvon Tꢀ64000 spectrometer (λ = 514.5 nm).
3. E. P. Horwitz, W. W. Schulz, in Metal Ion Separation and
Preconcentration: Progress and Opportunities, Eds A. H. Bond,
M. L. Dietz, and R. D. Rogers, Am. Nucl. Soc., 1998, Ch. 20.
4. V. N. Romanovskiy, I. V. Smirnov, A. Y. Shadrin, B. F.
Myasoedov, Spectrum´98, Proc. Int. Topical Meeting on Nuꢀ
clear and Hazardous Waste Management, La Grange Park,
Illinois, Am. Nucl. Soc., 1998, 576.
5. T. H. Siddall, J. Inorg. Nucl. Chem., 1964, 26, 1991; D. G.
Kalina, E. P. Horwitz, L. Kaplan, A. C. Muscatello, Sep. Sci.
Tech., 1981, 16, 1127.
6. S. M. Bowen, E. N. Duesler, R. T. Paine, Inorg. Chem.,
1983, 22, 286.
7. S. M. Bowen, E. N. Duesler, R. T. Paine, Inorg. Chem.,
1982, 21, 261.
8. S. M. Bowen, E. N. Duesler, R. T. Paine, Inorg. Chim. Acta,
1982, 61, 155.
9. J. Petrova, S. Momchilova, E. T. K. Haupt, Phosphorus,
Sulfur, Silicon, 2002, 177, 1337.
10. L. J. Caudle, E. N. Duesler, R. T. Paine, Inorg. Chim. Acta,
1985, 110, 91.
11. S. Karthikeyan, R. T. Paine, R. R. Ryan, Inorg. Chim. Acta,
1988, 144, 135.
12. G. S. Conary, R. L. Meline, L. J. Caudle, E. N. Duesler,
R. T. Paine, Inorg. Chim. Acta, 1991, 189, 59.
13. M. W. Peters, E. J. Werner, M. J. Scott, Inorg. Chem., 2002,
41, 1707.
14. O. I. Artyushin, E. V. Sharova, I. L. Odinets, S. V. Lenevich,
V. P. Morgalyuk, I. G. Tananaev, G. V. Pribylova, G. V.
Myasoedova, T. A. Mastryukova, B. F. Myasoedov, Izv. Akad.
Nauk, Ser. Khim., 2004, 2395 [Russ. Chem. Bull., Int. Ed.,
2004, 53, 2499]; O. I. Artyushin, E. V. Sharova, I. L. Odinets,
K. A. Lyssenko, D. G. Golovanov, T. A. Mastryukova, G. A.
Pribylova, I. G. Tananaev, G. V. Myasoedova, Izv. Akad.
Nauk, Ser. Khim., 2006, 1387 [Russ. Chem. Bull., Int. Ed.,
2006, 55, 1440]; E. V. Sharova, O. I. Artyushin, A. S. Sharov,
G. V. Myasoedova, I. L. Odinets, Tetrahedron Lett., 2008,
49, 1641.
The starting ligands were obtained as described earlier.14
Their physicochemical constants are identical with the literaꢀ
ture data.
Synthesis of complexes 1—5 (general procedure). A solution
of an appropriate metal nitrate in EtOH (3 mL) was added to
a solution of ligand L1—L3 (0.5 mmol) in EtOH (3 mL) (for L1 or
L3) or in a mixture of EtOH (3 mL) and CHCl3 (2 mL) (for L2).
The L : M ratio was 1 : 1, 2 : 1, and 3 : 1. The precipitates that
formed were filtered off, recrystallized from an appropriate solꢀ
vent (see Table 2), and dried over P2O5 in vacuo to a constant
weight.
Single crystals were grown from MeCN (2) and EtOH (3a,b,
4). Xꢀray diffraction analysis was carried out on a SMART 1000
CCD diffractometer (MoꢀKα radiation, graphite monochromaꢀ
tor, ωꢀscan mode) for complexes 3a and 3b and on a SMART
APEX2 CCD diffractometer (MoꢀKα radiation, graphite monoꢀ
chromator, ωꢀscan mode) for complexes 2 and 4. The structures
were solved by direct methods and refined by the leastꢀsquares
method in the anisotropic fullꢀmatrix approximation on F2
.
hkl
The hydrogen atoms of the N—H groups in structures 2 and 4
and the hydrogen atoms of the O—H groups of ethanol solvate
molecules in structures 3a and 3b were located from difference
electronꢀdensity maps. The hydrogen atoms of the C—H groups
were positioned geometrically. The positions of all hydrogen atꢀ
oms were refined isotropically using the riding model. An analyꢀ
sis of the Fourier series revealed that one of the phenyl rings in
the crystal of complex 2 is disordered over two positions (50 : 50).
In structures 3a and 3b, the butyl fragment is disordered over two
positions (70 : 30). Selected crystallographic parameters and the
data collection and refinement statistics are given in Table 7. All
calculations were performed with the SHELXTL PLUS program
package.18
15. B. W. Veal, D. J. Lem, W. T. Carnall, H. R. Hoekstra, Phys.
Rev., Sect. B, 1975, 12, 5651.
This work was financially supported by the Russian
Foundation for Basic Research (Project Nos 05ꢀ03ꢀ33094
and 05ꢀ03ꢀ32692).
16. L. I. Katzin, G. W. Mason, D. F. Peppard, in Recent Develꢀ
opment in Separation Science, Ed. N. N. Li, CRC Press, Boca
Raton, Fl, 1982, Vol. 7, p. 207.
17. A. M. Rozen, B. V. Krupnov, Usp. Khim., 1996, 65, 1052
[Russ. Chem. Rev., 1996, 65 (Engl. Transl.)] (and references
therein).
References
18. G. M. Sheldrick, SHELXTLꢀ97, Version 5.10, Bruker AXS
Inc., Madison,WIꢀ53719, USA.
1. T. Ya. Medved´, M. K. Chmutova, N. P. Nesterova, O. E.
Koiro, N. E. Kochetkova, B. F. Myasoedov, M. I. Kabachꢀ
nik, Izv. Akad. Nauk SSSR, Ser. Khim., 1981, 2121 [Bull.
Acad. Sci. USSR, Div. Chem. Sci., 1981, 30 (Engl. Transl.)].
2. E. P. Horwitz, D. G. Kalina, H. Diamond, D. G. Vanderꢀ
grift, W. W. Schultz, Solvent Extr. Ion Exch., 1985, 3, 75.
Received December 7, 2007;
in revised form April 10, 2008