J inorg nucl. Chem., 1979, Vol. 41, pp I~g-199
Pergamon Press
Printed in Great Britain
STRUCTURAL STUDIES ON ACTINIDES
C ARB OXYLATES--III [ 1]
PREPARATION,
PROPERTIES
AND CRYSTAL
STRUCTURE
OF LITHIUM
GLUTARATE
HYDROGENGLUTARATE
DIOXOURAN ATE(VI)TETRAHYDRATE
UO2(CsH604)Li(CsHTO4)'4H20
F. BENETOLLO and G. BOMBIERI*
Laboratorio di Chimica e Tecnologia dei Radioelementi del C.N.R., Corso Stati Uniti, 35100 Padova, Italy
and
J. A. HERRERO and R. M. ROJAS
Instituto de Quimica lnorganica "ELHUYAR" C.S.I C., Madrid, Spain
(Received 5 June 1978)
A~traet--The synthesis, thermal behaviour and crystal structure of lithium glutaratehydrogenglutaratedioxouranate(VI) tetrahydrate is described. The compound crystallizes in the monoclinic system, space group P2dn
with a = 9.143(3), b =26.825(11), c =7.776(2) A, /3 = 101.2°(2) and Z = 4 . The two glutarato ligands behave
differently; one is bridging the uranyl groups in infinite chains running approximately in the u axis direction, the
second is bridging the uranyl and the lithium ions. The carboxylic groups are chelated on the uranium and
monodentate on the lithium. The structure is linked through a network of hydrogen bonding involving water
molecules and oxygen atoms from the carboxylato groups. The geometry around the uranium is approximately
hexagonal bipyramidal while the lithium is tetrahedrally coordinated with one glutarate oxygen and 3 water
oxygens.
INTRODUCTION
In a previous paper, the synthesis and thermal behaviour
of uranyl glutarate and its derivatives with lithium,
sodium and potassium have been described[2]. It was
found that sodium and potassium uranyl glutarate precipitated in the system glutaric acid-uranyl nitrate-alkaline hydroxide in molar ratio 3:2:6. When this procedure is used in the preparation of the lithium
compound, a new product identified as lithium glutaratehydrogenglutaratedioxouranate(VI) tetrahydrate is
formed,
EXPERIMENTAL
The compound was isolated in the system glutaric acid-uranyl
nitrate-lithium hydroxide in molar ratio 3:2:5.5 at pH =4.4.
Crystals suitable for X-ray work in the form of pale-yellow
prisms, were obtained by recrystallization from water.
The uranium content of the sample was determined gravimetrically as U3Os, after precipitation with ammonium
hydroxide. Carbon and hydrogen were determined by the microcombustion method, using a Coleman mod. 33 microanalyzer.
Lithium was measured by flame emission spectrophotometry
using a Pye Uuicam mod. SP 90 serie 2 spectrophotometer. Calc.
for Li[UOz(CsH604)(CsHTO4)]4H20 (%): C 19.68; H 3.47: U
39.01; Li 1.13. Found (%): C 19.71; H 3.36; U 39.02; Li 1.14).
The thermograms were obtained using a Deltatherm mod.
D-2000 differential thermal analysis and D-4000 thermobalance
assembly. The samples were ignited in static air; precalcined
alumina was used as reference material and a heating rate of
IO°CIm. was selected.
The IR spectra were obtained using a Perkin-Elmer 325 spectrophotometer, with samples in KBr pellets or Nujol mulls.
The X-ray powder diffraction patterns were obtained using a
114.8 mm Debye-Scherrer camera and CuK~ radiation.
*Author for correspondence.
Crystal data. C,oH21Ot4ULi, FW 610.25, monoclinic, a =
9.143(3), b = 26.825(11), c = 7.776(2) ,~,,/3 = 101.2°(2), U = 1871 ~,,
Dc=2.16gcm -3 for Z=4, AMoK~=0.7107A, /J,(MoKt~)=
83.5 cm -t, space group P2j/n.
The X-ray intensity data were collected on a four-circle Philips
PW 1100 automated diffractometer with graphite-monochromated MoKa radiation. The unit cell was determined on the
basis of 25 strong reflections found by mounting the crystal at
random, varying the orientation angles ,/, and X in the range of
120° each with the detector position varying between O = 6" and
d = 10°. For the determination of precise lattice parameters 25
strong reflections with 8 ° < 0 < 15° were considered and the
precise diffraction angles # were evaluated as centres of gravity
of their profiles I = F(O) averaging over positive and negative O
values. Integrated intensities for hkl reflections with k, 1 ~>0 and
3° ~ 0 ~<250 were measured using the 0120 scan method with a
scan speed of 1.20° rain ', scan width of 1.3° and two background
counts of 10 s at each end of the scan.
Of the 3161 reflections thus considered the 1816 having a net
intensity greater than 3o- (tr = standard error based on count
statistic) were used in the structure determination and refinement. o-(I) = [CT ~- (tc/tb)2(Bi + B2) + (pi)211t2 where CT is the
total integrated peack count obtained in scan time tc, B~ and B2
are background counts each obtained in time ~tb and 1=
CT - (tcltb)(B~ + B2). A value of 0.04 was assigned to the factor
p in the formula to calculate o-(I) to allow for other errors.
Every two hours, two standard reflections were monitored to
check the crystal stability. These were found to decrease nearly
linearly by about 20% during the course of data collection,
presumably as a result of crystal decomposition. The observed
intensities were corrected for this apparently isotropic crystal
decomposition.
Solution and refinement of the structure. The uranium atoms
were located in a three-dimensional Patterson synthesis.
Subsequent refinements and difference Fourier synthesis
revealed the presence of all non-hydrogen atoms. The structure
was then refined by the least-squares procedure using anisotropic
thermal parameters only for the atoms belonging to the uranium
195
F. BENETOLLO et al.
196
coordination sphere and isotropic for all others. During the
refinement the quantity minimized was X w(IFoI-IFcl) 2 where
Fo and Fc are the observed and calculated structure amplitudes
and where the weights w are taken as unitary. Atomic scattering
factors for the uranium were taken from Ref. [3], for the other
non-hydrogen atoms from [4] and [5] for the hydrogen atoms.
The anomalous dispersion terms for U were applied to the
calculated structure factors[6]. The structure converged to R =
0.08. Final difference Fourier syntheses revealed only two peaks
of about 1/~ 3 in the proximity of the uranium positions but not
the hydrogen atom positions. The positions of hydrogens belonging to the aliphatic chains were introduced at their idealized
positions, C-C-H 1090 and C-H 1.08/~, and they were included
as fixed contributions in a final refinement where the thermal
parameter of a hydrogen atom was assumed to be equal to that of
the carbon to which it was attached. The structure converged to
R = 0.079.
All data processing and computation were carried out using the
SHELX 76 program package [7].
The final positional and thermal parameters of atoms appear in
Table I. A listing of the observed and calculated structures
amplitudes for those data used in the refinements is available
from the authors.
RESULTS AND DISCUSSION
Thermal analysis and IR spectroscopy. The compound
is dehydrated between 90 and 160°C and when anhydrous, it transforms at 200-270°C into a mixture of
uranyl glutarate and lithium glutarate, as indicated by the
X-ray powder pattern of a sample heated at 300°C.
Finally, decomposition occurs between 340 and 700°C;
U02 and Li2CO3 can be identified as intermediate
products, Li2U207 being the residue at 800°C [8].
The thermal behaviour of the compound (see Fig. 1)
can be indicated as follows:
90-160*C
Li[UO2(CsH604)(CsHvO4)]4H20
Li[UO2(CsH604) (C5H704)]
200-270°C
) UO2(C5H604)
340-700°C
+ 1 Li2(C5H604)
1
) ~ Li2U207
z
The IR spectrum of the initial compound shows the
bending (8) and asymmetric stretching (vas) vibrations of
the uranyl group at 256 and 915 cm -t, respectively. A
strong band observed at 1720cm -~ in the hydrated
compound appears at 1710cm -~ in the anhydrous one,
and can be assigned to the C=O stretching of non-associated carboxylic acid[9, 10].
Overall crystal structure. The structure is shown projected down the c axis in Fig. 2. Table 2 contains the
most significant inter and intramolecular distances and
the bond angles. This structure is built up from two
distinct coordination polyhedrons. One is formed by the
uranium atoms surrounded by eight oxygen atoms O(1),
O(2), O(3), O(4), O(5), O(6), O(7), 0(8) in the shape of a
distorted hexagonal bipyramid. The two apical oxygens,
O(l) and O(2), constitute the uranyl group which is
perpendicular to the equatorial plane of the bipyramid
formed by the other six oxygen atoms. In the second
Table 1. Atomic coordinates (× 104, for hydrogen atoms x 103), anisotropict temperature factors and isotrupic
(u× 103)with e.s.d.'s in parentheses
X
U
O(1)
0(2)
0(3)
0(4)
0(5)
0(6)
0(7)
0(8)
0(9)
O(10)
O(11)
O(12)
O(13)
O(14)
C(1)
C(2)
y
275(1)
1532(0)
152(30)
1630(11)
404(29)
1405(10)
-2356(19)
1786(7)
3052(19) 1418(8)
2177(19) 2167(8)
-683(22)
2376(8)
848(24)
658(8)
- 1525(23)
841(8)
-4883(29)
-778(10)
-4154(33) - 1384(12)
5568(27)
815(9)
1727(27) 3198(9)
-8046(30) - 1038(10)
1665(29) 5072(10)
3298(34) 1882(12)
4898(32) 2103(11)
Z
UI l
3602(2) 19.8(5)
1448(23) 33(10)
5699(22) 26(9)
3243(37)
16(9)
4069(39)
13(9)
4312(40)
8(7)
4075(40) 28(11)
3115(47) 37(12)
2870(42) 31(12)
2168(36)
79(9)
477(41) 100(10)
4067(33) 67(7)
4497(34) 68(7)
2341(38)
84(9)
1613(36) 79(8)
4460(44) 46(8)
4942(42) 43(7)
C(3)
5208(33)
2411(11) 3313(42)
42(8)
C(4)
6783(33)
2624(12) 3863(46)
51(8)
C(5)
C(6)
C(7)
7954(37)
- 547(37)
- 870(45)
2221(13) 3636(46)
539(13) 2705(47)
11(15) 2165(63)
C(8)
-2351(49)
- 180(17)
C(9)
-2615(41)
-688(14)
C(10)
Li
-4029(41)
-6392(76)
-948(14)
-677(26)
U22
U33
U23
UI3
UI2
32.0(5)
13(10)
3104 )
29(11)
45(15)
55(14)
46(15)
4(13)
39(13)
97.4(10)
282(40)
150(36)
155(25)
165(26)
173(27)
154(27)
196(33)
180(30)
6.3(10)
32(15)
- 13(17)
16(13)
- 10(15)
16(16)
-21(16)
18(18)
-23(16)
17.4(5)
23(17)
20(14)
41(13)
32(12)
28(13)
32(14)
23(16)
44(16)
-0.1(7)
17(7)
-5(8)
8(8)
7(8)
10(9)
-4(10)
-1(10)
-3(10)
H(C2)
H(C2)
H(C3)
H(C3)
H(C4)
H(C4)
51(9)
55(9)
80(12) H(C7)
H(C7)
1872(64)
88(14) H(CS)
H(C8)
1101(53)
64(10) H(C9)
H(C9)
1282(51) 60(10)
3471(94) 75(19)
tln the form: exp [- 2¢r22 Ui~aiaihlhj].
x
569
499
439
517
688
697
y
180
234
270
217
294
275
z
523
607
299
220
301
521
- 23
- 49
- 269
- 304
- 169
- 262
- 22
- 5
- 19
8
- 92
- 65
318
95
313
102
170
- 28
197
Structural studies on actinides carboxylates--IIl
Table 2. Distances (,~) and angles (°) with e,s.d.'s in parentheses
U-O(2)
U-O{6)
U-O(5)
U-O(8)
C{6)-O(71
C(6)-O(8)
C(61-C(71
C(7)-C(8)
C(81-C(9)
C(9)-C(1O)
C(10)-0(91
C(IO~O(IO}
1.65(21
2.48(2)
2.42(2)
2.47(2)
1.29(41
1.23(41
1.49(5)
1.42(6)
1.49(6)
1.50(5)
1.23(51
1.32(5)
Li-O( 13 }
Li-O(14)vm
1.86(7)
2.02(7)
0{41.,. 0(5l
0(5)... 0(6)
0(3)... 0(8)
0(12)... 0(5)
0(12)... 0(10)TM
0(141... 0(7)v
0(11).. :'0(8)I
2.18(3)
2.64(3)
2.68(3)
2.80(3)
2.61(4)
2.74(3)
2.99(4)
Oil >1!-0(2)
177(1)
0(31-U-0(6l
53(1)
O{l i-U-O~3)
89(11
O{I1-U--0(61
93(1)
0(21-U-0{3)
92.(11
U.-()(~>C{51H
94(2)
:, -0(6>Ct5) l!
91(2)
0!31J-C(51--0(6t 122(31
Oi3)"-C(5)--C{4) 124(3)
0{6)r-C{5)-C(4) 113(3)
Ci5)-C(4)-C{3)
110(3)
C~41-C(3}-C(2}
106(2)
c (3 ~--('i2)-C(I)
109(2)
0(4)-U-0(51
O(I)-U-O(41
O(1)-U-O(7)
0(2)-U-0(4)
0(2)-U-0(7)
U-O(5)-C(I)
U-0{4)-C{1)
0(41--C(11-0(5)
0(5)-C(11-C(2)
0(41-C(11-C(2)
C(91-C(101--O(10)
C(9~C(101-0(9)
0t10~C(101-0(9)
53(1)
91(11
88(1)
88(11
89(I)
97(2)
92(2)
118(31
120(31
122(31
111(31
123(3)
126(41
O{9}-Lb-O(13)
106(4)
O(13Y-Li-O(II)*~ 119(41
( (lO~-Ot9)-Li
166(3)
O(9)-Li-O(l 1)m 109(31
O(131-Li-O(14)vm 115(31
U -0{ 1*
U-O(3)
U4){41
U-O(7)
Cil I-0{41
C;I)-()151
C{I ),-C{2)
('{21-C{3t
~713}-C~4~
7~4)-Ci5}
C~51-0{31'
~{5}-0!¢ff
1.68(2I
2.46(2}
2.51{2)
2.45(2)
l 29(4}
1.27{7}
1.55(4)
I 58{41
1.5~,i41
1.56(4}
I 22{a)
1.29(41
1.89{81
] -0(1~ III ] 04{7)
[ I-0{9t
0(3i. (){61
0~7'~. 0(8)
0~41 {}{7)
O{ll} . O{14P~
O~111 0(4)
!)!12t 0(3) ~
0(12} 0(131TM
2.20(3)
2.19(3)
2.86(3)
2.82(4)
2.81(3)
2.86(4)
2.90(4)
0(71-U-0(8)
O(I)-U-O(5)
0(11-U-0(8)
0(21-U-0(5)
0(2)-U-0(8)
U--0(7)-C(6)
U-0(8)-C(6)
0(7)-C(6)-0(8)
0(71-C(61-C(71
0(81-C(6)-C(7)
C(61-C(71-C(81
C(7)-C(81--C(9)
C(8)-C(9)-C(10)
53(11
91(11
89(11
91(11
89(11
92(2)
93(2)
121(31
116(3)
123(3)
121(4)
118(4)
117(4)
O{9)-Li-O(141vnl
O{1l)m-Li-O(14)vtn
103(4)
104(3)
Key fer symmetry
II
IV
~
1
~+x. ~ y, ~+z
~H
~- ~. ~+y, ~ - z
t
1
V
-l+x,
y,
1
~-x,
1
Vlll - 5 - x ,
z
I
1
~+y,
1
~-z
1
-~+y, } - z
polyhedron the lithium ion is tetrahedrally coordinated
with three water oxygens O(11), O(13), O(14) and one
glutarate oxygen 0(9).
The U polyhedra are connected through bridging glutarato groups, each ligand being chelated via 0(3) and 0(6)
to one uranyl unit and via 0(4) and O(5) to another uranyl
unit. In this way infinite chains, glutarato-U-glutarato,
are formed in the direction of the a axis. The second
glutarato group is chelated through 0(7) and 0(8) to the
uranium, thus completing its equatorial hexacoordination
and with the other carboxylic group is coordinated to the
lithium atom through 0(9). The lithium polyhedra are in
the proximity of inversion centers and are linked two by
two through relatively short O(14)...O(11)' contacts,
2.81 ,~., that could be ascribed to hydrogen bonding. The
fourth water molecule O{ 12), not coordinated, is involved
in short contacts either with the non-coordinated O(10)
oxygen atom of the glutarato group or with oxygen
Ill
-x,
1
-y, l--z
1
1
VI ~-x, -~+y, ~--z
IX
-x,
-y,
-z
atoms belonging to the uranium and lithium coordination
sphere. The existence of these contacts suggests the
presence of a network of hydrogen bonding connecting
the polymeric chains.
The uranium coordination polyhedron. The characteristic dimensions for the uranyl group are observed in
this structure. (Table 2) The O(1)-U-O(2) angle 177(11° is
linear and the uranyl distances close to the usual value of
ca. 1.70/k [U-O(1), 1.68(21 and U-O(2), 1.65(2)]. The six
equatorial oxygens are coplanar within _+0.06]k. The
equation of their best plane in direct space is - 1.3672X 5.0440Y + 7.6305Z = 1.9459 and the deviations (in /I, of
the atoms belonging to this plane are: 0(3) -0.050, 0(4)
0.026, 0(5) -0.046, 0(6) 0.058, 0(7) -0.017, 0(8) 0.028, U
- 0,007.
The highest deviations are presented by the four
oxygens of the U-U bridging glutarato group, showing
some ~t~in in the structure which is also reflected by the
198
F. BENETOLLO et al.
10-
t •
2O
r
T~
I
I
30-
I
40-
I
r
500
100
2OO
3O0
~00
5OO
6OO
700
800
g00*C
T (* C)
Fig. 1. DTA and TG curves of [UO2(CsH~O4)(CsHTO4)]Li.4H20.
Fig. 2. Cell content viewed down the c axis.
different conformations of the two aliphatic chains. In
fact, while the glutarato group bridging the uranium and
a lithium atom has essentially a trans planar conformation, the conformation of the chain in the glutarato
group belonging to the polymeric chains is trans and
cis-planar (Table 3).
The U--O distances in the equatorial plane range between 2.42(2) and 2.51(2),i~ with an average value of
2.46/~, which is comparable with those reported for
analogous compounds, e.g. in Na[UO2(OOCCH3)3] U O(acetate) = 2.49A[11]. The three independent O . . . . O
Table 3. Torsion angles (°)
C(6)--C(7)-C(8)--C(9)
C(7)-C(8)--C(9)--C(10)
C(1)--C(2)--C(3)--C(4)
C(2)--C(3)--C(4)-C(5)
171.7
162.2
180.0
98.4
The torsion angle W(IJKL) is defined as the
angle between the vector Jl and the vector
KL when viewed down JK. The signe of W is
positive if Jl is to be rotated clockwise into
KL and negative if anticlockwise[15].
199
Structural studies on actinides carboxylates--Ill
bite distances across the chelated carboxylic groups
[2.19(3)]~ average value] and across the monodentate
carboxylic group [2.27(4),~] are comparable to those
reported in bis(iminodiacetato)dioxouranium(VI)[l]. The
other O . . . O approaches in the equatorial plane are 2.64,
2.68 and 2.86 A, two of them being shorter than the sum
of the van der Waals radii[12].
The lithium coordination polyhedron polyhedron. The
tetrahedral coordination of the lithium ion is well
known[13]. In the present study the Li-O distances vary
between 1.86 and 2.02 A,, compared with 1.89-2.04 A, in
lithium acetate dihydrate[14J, while the angles vary between 1030 and 119°. As the standard deviations are high
for all the distances reported in this structure no particular meaning is attributable to the reported difference in
the lithium oxygen bond distances and angles.
Hydrogen bonding system.+ The contacts between the
atoms are related mainly to the water-water and watercarboxylic oxygen interactions. The approaches are
illustrated in Fig. 1 and in Table 2 and are attributable to
the presence of a network of hydrogen 0onds. In fact,
the four non-equivalent water molecules have different
roles in the structure. The H20(ll), HzO(13) and H2(Y(14)
water molecules act as ligands for the Li + ions while
H20(12) binds carboxylate oxygen atoms and H20(13) by
means of hydrogen bonding. The HzO(ll) molecules
have interactions with H20(14)v~, 0(4) and 0(8) ~ from
two different chelated carboxylate groups, besides an
electrostatic contact to the lithium ions. [O(11)... O(41
2.81 A: O(11).,. O(14)v~ 2.82 A; O(11)... 0(8)' 2.99 ~,l.
Fhese contacts are in the directions of a distorted tetrahedron with HzO(ll) at the centre, and they could be
assigned to hydrogen bonding. H20(13) forms onlYo a
contact with H20(12) TM [O(13)IX...O(12) TM 2.90A].
H20(14) exhibits two probable hydrogen bonds with
H20(ll) and 0(7) of a chelated carboxylato group
!O(14)v'... O(11) 2.82 A and O(14)v~... 0(7) 2.74 A],
tin the description of the hydrogen bonding system, for the
,,ymmetry related atoms the superscripts of the key given in
]able 2 are used.
JINC Vol. 41, No. 2--E
thus forming a six membered ring having a chair
configuration, with lithium and O(11) and the
centrosymmetnc related atoms. The non-coordinated
H20(12) TM are approximately at the centre of tetrahedra
with, at the corners, H20(13) TM, O(10)TM belonging to the
monodentate carboxylate groups and 0(5) ~v, O(3) 1 from
different
chelated
carboxylate
groul~s
[O(12)'v...O(13) TM 2.90A O(12)~v...O(10) TM 2.61A,
O(12)lV... 0(5) tv 2.80 A, and O(12)~v... 0(3) TM 2.86 ]~].
The strongest interaction involve the monodentate
carboxylate group suggests the presence of a hydrogen
attached to O(10).
Acknowledgemem--We thank Mrs. M. Magnaboscofor technical
assistance.
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