Uranium-sulfilimine chemistry. Hydrolysis of Cp*2UCl2 with HNSPh2·H2O and the crystal structure of Cp*2UCl(OH)(HNSPh2), a metallocene terminal hydroxy complex of tetravalent uranium

Article abstract of DOI:10.1016/j.jorganchem.2004.03.029

The reaction of Cp*₂UCl₂(HNSPh₂) with HNSPh₂·H₂O in 1:1 stoichiometry, produces Cp*₂UCl(OH)(HNSPh₂) in good yield. This is the first structurally characterized metallocene f-element complex containing a terminal hydroxy ligand. Cp*₂UCl(OH)(HNSPh₂) is an intermediate in the formation of a tetra uranium-oxo-cluster [Cp*(Cl)(HNSPh₂)U(μ₃-O) (μ₂-O)₂U(Cl)(HNSPh₂) ₂]₂, which forms by hydrolysis of Cp*₂UCl₂ with excess HNSPh₂·H₂O.

Full text of DOI:10.1016/j.jorganchem.2004.03.029

Journal of Organometallic Chemistry 689 (2004) 2029–2032
www.elsevier.com/locate/jorganchem
Uranium-sulfilimine chemistry. Hydrolysis of Cp*2UCl2 with
HNSPh2 ꢀ H2O and the crystal structure of Cp*2UCl(OH)(HNSPh2),
a metallocene terminal hydroxy complex of tetravalent uranium
a,
b,
a,
*
Kanahara A.N.S. Ariyaratne *, Roger E. Cramer *, Geoffrey B. Jameson
,
c,
*
John W. Gilje
a
Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
Department of Chemistry, University of Hawaii at Manoa, 2545, The Mall, Honolulu, HI 96822, USA
b
c
Department of Chemistry, James Madison University, MSC 7701, Harrisonburg, VA 22807, USA
Received 13 January 2004; accepted 23 March 2004
Abstract
The reaction of Cp*2UCl2(HNSPh2) with HNSPh2 ꢀ H2O in 1:1 stoichiometry, produces Cp*2UCl(OH)(HNSPh2) in good yield.
This is the first structurally characterized metallocene f-element complex containing terminal hydroxy ligand.
a
Cp*2UCl(OH)(HNSPh2) is an intermediate in the formation of a tetra uranium-oxo-cluster [Cpꢁ(Cl)(HNSPh2)U(l3-O)(l2-
O)2U(Cl)(HNSPh2)2]2, which forms by hydrolysis of Cp*2UCl2 with excess HNSPh2 ꢀ H2O.
Ó 2004 Elsevier B.V. All rights reserved.
Keywords: f-element; Actinide; Uranium; Hydroxide; Metallocene
1. Introduction
product that could not be characterized. In a previous
paper we reported that the reaction of Cp*2
UCl2(HNSPh2) with excess HNSPh2 ꢀ H2O, a reagent
which supplies controlled amounts of water and absorbs
hydrogen chloride generated during hydrolysis, forms
a tetra-uranium-oxo cluster [Cpꢁ(Cl)(HNSPh2)U(l3-
O)(l2-O)2U(Cl)(HNSPh2)2]2 [14]. During the formation
of this cluster an intermediate with a NMR Cpꢁ reso-
nance at about )2.7 ppm, appears and disappears [15].
We have now identified this intermediate as Cp*2
UCl(OH)(HNSPh2), which is the first structurally
characterized metallocene f-element complex containing
a terminal hydroxy ligand.
Organometallic f-block hydroxide complexes are
rare. A few actinide metallocene hydroxides have been
reported [1,2] and there are a few lanthanide analogues
[3–11]. For the actinindes several closely related, but not
formally organometallic, molecular complexes have
been structurally characterized [12,13]. The preparation
of f-element hydroxides generally involves controlled
hydrolysis of a suitable metal precursor. For example,
Andersen and co-workers synthesized the bridging hy-
droxide Cp00 U2(OH)2 by treating Cp00 U, Cp00 ¼ 1,3-
4
3
(Me3Si)2C5H3 or 1,3-(t-Bu)2C5H3, with one equivalent
of water [1]. When we attempted to prepare a metallo-
cene hydroxo complex by the reaction of Cp*2UCl2,
Cp* ¼ C5Me5, with H2O, we obtained a heterogeneous
2. Experimental
2.1. General remarks
* Corresponding authors. Tel.: +1-540-568-3729; fax: +1-540-568-
7938 (J.W. Gilje).
All reactions were carried out under a dinitrogen at-
mosphere using normal Schlenk, glove box and vacuum
techniques. Solvents were dried and deoxygenated over
E-mail addresses: k.a.ariyaratne@massey.ac.nz (K.A.N.S. Ari-
yaratne), rogerc@gold.chem.hawaii.edu (R.E. Cramer), g.b.jame-
son@massey.ac.nz (G.B. Jameson), giljejw@jmu.edu (J.W. Gilje).
0022-328X/$ - see front matter Ó 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2004.03.029

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K.A.N.S. Ariyaratne et al. / Journal of Organometallic Chemistry 689 (2004) 2029–2032
sodium-benzophenone and were distilled prior to use.
Cp*2UCl2 was prepared using a literature method [16]
and HNSPh2 ꢀ H2O was purchased from Aldrich chem-
ical company. Cp*2UCl2(HNSPh2) was synthesized by
the reaction of Cp*2UCl2 with anhydrous HNSPh2 [14].
1H NMR spectra were obtained using a Nicolet QE 300
MHz spectrometer and samples were prepared in d6-
benzene, d8-toluene or d8-tetrahydrofuran. IR spectra
were recorded on a Perkin Elmer 1430 spectrometer or a
Nicolet-740 IR spectrometer operating in the Fourier
transform mode.
polarization effects and for decay of the intensities of
check reflections during data collection and an empirical
absorption correction was applied. The position of the
uranium was determined by direct methods and the re-
maining atoms were located in subsequent rounds of
difference Fourier maps and least squares refinements.
All non-hydrogen atoms were refined anisotropically
with restraints applied to non-U atoms. After an empir-
ical absorption correction, the H atoms were added at
calculated positions to the Cpꢁ methyl groups, phenyl
groups and the two benzene solvate molecules. The final
refinement yielded R values, R1 ¼ 6:51%, wR2 ¼ 16:30%
(I > 2rðIÞ and R ¼ 9:81%, wR2 ¼ 18:45% (all data)).
Crystalline Cp*2UCl(OH)(HNSPh2) belongs to the
monoclinic space group P2ð1Þ=c. There are two nearly
identical Cp*2UCl(OH)(HNSPh2) molecules and two
benzene molecules in the asymmetric unit leading to
eight molecules of Cp*2UCl(OH)(HNSPh2) and eight
benzene molecules in the unit cell. Least squares plane
calculations performed on the two benzene molecules in
the asymmetric unit with respect to the neighboring
phenyl groups indicate that these two benzenes are
symmetrically non-equivalent. The crystal, data collec-
tion and refinement information are summarized in
Table 1 and important bond lengths and bond angles
in Table 2. A perspective drawing of Cp*2UCl(OH)
(HNSPh2) is shown in Fig. 1.
2.2. Synthesis of Cp*2UCl(OH)(HNSPh2)
In a glove box, a solution of 73 mg (0.33 mmol) of
HNSPh2 ꢀ H2O in 10 ml of benzene was slowly added
to a solution of 193 mg (0.33 mmol) of Cp*2
UCl2(HNSPh2) in 15 ml of benzene. The sample turned
light green from dark orange and a white precipitate
began to form. After 3 h the solution was filtered
through a medium porosity frit and evaporated to dry-
ness. The green oily residue was dried under vacuum
overnight, dissolved in 3 ml of benzene and stored at
room temperature for a week during which period green
crystals formed. These crystals were separated from the
solution by filtration, rinsed with 2 ml of pentane and
dried under vacuum to yield 120 mg (63.7%) of
1
Cp*2UCl(OH)(HNSPh2). H NMR (d8-thf) at 23 °C:
)2.7 ppm (s, 30H, Cp*), )10.5 ppm (br), )0.5 (br), )163
ppm (br); at )60 °C: )4.1 ppm (Cp*, 30H), )2.0 ppm,
)0.5 ppm, )15.1 ppm, )163 ppm (br), 7.2 (br), 7.4 (br),
9.2 (br). IR (cmꢂ1): 3290 (w), 3150 (br), 3050 (s), 2900
(m), 2870 (m), 2250 (m), 1950 (s), 1875 (s), 1810 (s), 1560
(s), 1455 (m), 1440 (s), 1350 (w), 1250 (w), 1150 (m),
1075 (m), 1020 (w), 990 (w), 915 (w), 810 (m), 745 (s),
Table 1
Crystallographic data for Cp*2UCl(OH)(HNSPh2)
Identification code
Empirical formula
Formula weight
Hydp2
C38 H48 Cl N O S U
840.35
293(2)
Temperature (K)
Wavelength (A)
0.71073
Monoclinic, Pð2Þ1=c
Crystal system, space group
Unit cell dimensions
690 (s) cmꢂ1
.
Cp*2UCl(OH)(HNSPh2) decomposes in solution
over several days (Section 3) and more slowly at room
temperature in the solid phase. As a consequence of its
instability we were unable to obtain a satisfactory ele-
mental analysis.
ꢀ
a (A)
14.503(5)
30.095(11)
ꢀ
b (A)
ꢀ
c (A)
17.048(9)
90
a (°)
b (°)
c (°)
Volume
102.20(3)
90
7273(5) A3
8, 1.531
Z, Calculated density (Mg/m3)
2.3. Data collection and reduction of X-ray data
Absorption coefficient (mmꢂ1
)
4.623
3312
F (0 0 0)
Crystal size (mm)
Single crystals of Cp*2UCl(OH)(HNSPh2) were se-
lected, mounted and sealed in thin-walled glass capillaries
under dinitrogen. A Nicolet R3 computer-controlled
diffractometer with graphite-monochromated Mo Ka
1.0 ꢃ 0.5 ꢃ 0.5
1.59° to 22.56°
ꢂ15 6 h 6 15, ꢂ6 6 k 6 32,
ꢂ2 6 1 6 18
h Range for data collection
Limiting indices
ꢀ
ꢀ
Reflections collected/unique
Completeness to theta ¼ 22.56
Refinement method
10095/9343 ½RðintÞ ¼ 0:0511ꢄ
radiation (Ka1 ¼ 0:70930 A, Ka2 ¼ 0:71359 A) and a
scintillation detector with pulse height analyzer were used
for the measurement of diffraction intensities. During
data collection, the intensities of three standard reflec-
tions were re-measured every 97 reflections in the data
set. Data manipulation, structure solution and refine-
ment were carried out using SHELXL 97_2 Program
System [17]. Data were corrected for Lorentz and
97.5%
Full-matrix least-squares on F 2
9343/812/799
1.077
Data/restraints/parameters
Goodness-of-fit on F 2
Final R indices [I > 2rðIÞ]
R indices (all data)
Largest differential peak
and hole (e Aꢂ3
R1 ¼ 0:0651, wR2 ¼ 0:1630
R1 ¼ 0:0981, wR2 ¼ 0:1845
2.079 and )2.474
)

K.A.N.S. Ariyaratne et al. / Journal of Organometallic Chemistry 689 (2004) 2029–2032
2031
ꢀ
Table 2
The N- - -Cl separations of about 3.0 A are within the
range for N–H- - -Cl hydrogen bonds [19]. This geome-
try resembles that in Cp*2UCl2(HNPPh3), Cp*2UCl2
(HNSPh2) and [Cpꢁ(Cl)(HNSPh2)U(l3-O)(l2-O)2U(Cl)
(HNSPh2)2]2 where N–H- - -Cl hydrogen bonding is
proposed [14,18].
ꢀ
Selected bond lengths (A) and angles (°) for Cp*2UCl(OH)(HNSPh)2
Molecule 1
U(1)–O(1)
U(1)–N(1)
U(1)–Cl(1)
N(1)–S(1)
S(1)–C(51)
S(1)–C(61)
2.117(9)
2.47(2)
2.746(4)
1.57(1)
1.81(2)
1.77(2)
U(1)–C(11)
U(1)–C(12)
U(1)–C(13)
U(1)–C(14)
U(1)–C(15)
2.77(1)
2.81(2)
2.79(2)
2.75(1)
2.79(1)
The most interesting structural question involves the
assignment of the oxygen bonded to the uranium as an
OH group. Based on an analysis of data in the Cam-
bridge Crystallographic Database [20], typical U@O
U(1)–N(1)–S(1)
Cl(1)–U(1)–O(1)
N(1)–S(1)–C(51)
128.4(7)
147.0(7)
110.2(7)
N(1)–S(1)–C(61)
C(51)–S(1)–C(61)
107.7(7)
98.1(7)
ꢀ
distances are less than 1.95 A, terminal U–OH should be
ꢀ
ꢀ
about 2.1 A, and U–OH2 should exceed 2.3 A. Some
comparisons include [U(tpa)2(OH)2]2þ, tpa ¼ tris[(2-
Molecule 2
U(2)–O(2)
U(2)–N(2)
U(2)–Cl(2)
N(2)–S(2)
S(2)–C(71)
S(2)–C(81)
2.117(9)
2.47(1)
2.757(4)
1.57(1)
1.78(2)
1.83(2)
U(2)–C(31)
U(2)–C(32)
U(2)–C(33)
U(2)–C(34)
U(2)–C(35)
2.73(1)
2.76(1)
2.80(1)
2.80(1)
2.77(1)
ꢀ
pyridyl)methyl]amine, with U–O distances 2.127(1) A
0
0
ꢀ
and 2.147(1) A [12]; HO–U(NN 3)(CH2PMe3), NN 3@
t
ꢀ
CH2CH2NSiMe2Bu , whose U–O distance is 2.145(6) A
[13]; H2O–UCp*2(Otf)2, Otf ¼ trifluoromethanesulfo-
nate, with a U–O distance to the coordinated water
molecule of 2.57
[21]; and Cp*2U(O-2,6-iPr-
ꢀ
A
U(2)–N(2)–S(2)
Cl(2)–U(2)–O(2)
N(2)–S(2)–C(81)
128.9(6)
147.4(3)
109.8(7)
N(2)–S(2)–C(71)
C(71)–S(2)–C(81)
109.1(7)
97.9(7)
C6H3)(O), which is a U(V) complex with a terminal O–
i
ꢀ
U distance of 1.859(6) A and a U–O(-2,6- Pr-C6H3)
ꢀ
ꢀ
separation of 2.135 (5) A [22]. Clearly, the 2.117 (9) A
U–O bond in Cp*2UCl(OH)(HNSPh2) falls in the range
expected for a hydroxide. It is too long for a terminal
oxo, and too short for a coordinated water molecule.
Additionally, the intermolecular distances O(1)–Cl(2),
ꢀ
ꢀ
3.25 A, and O(2)–Cl(1), 3.32 A, respectively, lie in the
range observed for O–H- - -Cl hydrogen bonding, which
also supports the assignment of the ligand as hydroxide
[19]. The U(2)–O(2)–Cl(1), 150.4°, and U(1)–O(1)–Cl(2),
152.5°, angles are consistent with a large U–O–H angle,
which would be expected if the U–O bond possesses
significant pi character.
Based on the structural evidence presented, the re-
action of Cp*2UCl2(HNSPh2) with HNSPh2 ꢀ H2O is
CpꢁUCl2ðHNSPh2Þ þ HNSPh2 ꢀ H2O
2
! CpꢁUClðOHÞðHNSPh2Þ þ ½H2NSPh2ꢄCl
2
Fig. 1. Ortep diagram of the non-hydrogen atoms of Cp*2UCl
(OH)(HNSPh2) showing the atom labeling scheme.
In this reaction, HNSPh2 ꢀ H2O is the source of a
controlled amount of water and absorbs HCl as it is
1
generated during hydrolysis. The H NMR spectrum of
3. Results and discussion
freshly prepared Cp*2UCl(OH)(HNSPh2) dissolved in
deuterated THF contains a sharp signal at )2.7 ppm;
this can be assigned to the Cpꢁ protons on the basis of
relative intensity. In addition, broad signals appear at
)0.5, )10.5, and )163 ppm. Upon cooling these peaks
sharpen considerably. By )60 °C the former two are
resolved into three resonances at )0.5, )2.0 and )15.1
ppm that can be assigned to the aromatic protons on the
phenyl groups. The resonance at )163 ppm is assigned
to the N–H proton by analogy to the value of )142 ppm
observed in Cp*2UCl2(HNSPh2) [18]. Based on this
assignment, the O–H proton resonance was not located.
However, exchange between the hydroxy and imino
protons was not eliminated.
The reaction of Cp*2UCl2(HNSPh2) with HNSPh2 ꢀ
H2O produces Cp*2UCl(OH)(HNSPh2), which is a
green crystalline compound. The heavy atom structure
of Cp*2UCl(OH)(HNSPh2) is very similar to Cp*2UCl2
(HNSPh2) [18] with the former being derived from the
latter by the substitution of a hydroxide for a chloride.
The bond distances and angles within the Cp*2U and
U–N(H)SPh2 moieties are unremarkable and lie in the
same range as those in Cp*2UCl2(HNSPh2), Cp*2UCl2
(HNPPh3) and [Cpꢁ(Cl)(HNSPh2)U(l3-O)(l2-O)2U(Cl)
(HNSPh2)2]2 [14,18]. Placing the imino hydrogen at its
calculated position, it is directed towards the chloride.

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[2] J. Berthet, M. Ephritikhine, M. Lance, M. Nierlich, J.J. Vigner,
Organomet. Chem. 460 (1993) 47.
In solution Cp*2UCl(OH)(HNSPh2) decomposes over
several days. NMR spectra monitored periodically show
that the amount of Cp*2UCl(OH)(HNSPh2) decreases
and peaks characteristic of Cp*2UCl2(HNSPh2), CpꢁH,
and HNSPh2 grow in. In addition, [Cpꢁ(Cl)(HNSPh2)
U(l3-O)(l2-O)2U(Cl)(HNSPh2)2]2 precipitates [14]. Ap-
parently, upon coordination to uranium, the hydroxyl
group becomes acidic enough to hydrolyze moisture
sensitive species. This may explain why organouranium-
hydroxy complexes are often difficult to obtain in a state
of high purity and in good yield.
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Crystallographic data (excluding structural factors)
for the structural analysis of Cp*2UCl(OH)(HNSPh2)
have been deposited with the Cambridge Crystallo-
graphic Data Centre, CCDC 227353. Copies of this in-
formation may be obtained free of charge from The
Director, CCDC, 12 Union Road, Cambridge CB2 1EZ,
UK (fax: +44-1223-336033; deposit@ccdc.cam.ac.uk or
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We are grateful to the National Science Foundation
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