(Diphenylphosphinoethyl)cyclopentadienyl complexes of yttrium and lutetium: Synthesis and structure

Article abstract of DOI:10.1007/s11172-007-0271-1

The reaction of LnCl₃?xTHF with Na(C₅H ₄CH₂CH₂PPh₂) followed by the in situ reaction with Na₂(C₁₄H₁₀) afforded the (C ₅H₄CH₂

Full text of DOI:10.1007/s11172-007-0271-1

Russian Chemical Bulletin, International Edition, Vol. 56, No. 9, pp. 1749—1751, September, 2007
1749
(Diphenylphosphinoethyl)cyclopentadienyl complexes
of yttrium and lutetium: synthesis and structure*
D. M. Roitershtein,a,bꢀ A. V. Romanenkov,a K. A. Lyssenko,c P. A. Belyakov,d and M. Yu. Antipinc
aL. Ya. Karpov Institute of Physical Chemistry,
10 ul. Vorontsovo Pole, 105064 Moscow, Russian Federation.
Fax: +7 (495) 975 2450. Eꢀmail: roiter@server.ioc.ac.ru
bDepartment of Chemistry and Biology, Moscow City Pedagogical University,
4 Vtoroi Sel´skokhozyaistvennyi proezd, 129226 Moscow, Russian Federation.
Fax: +7 (495) 308 9546
cA. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences,
28 ul. Vavilova, 119991 Moscow, Russian Federation.
Fax: +7 (499) 135 5085
dN. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences,
47 Leninsky prosp., 119991 Moscow, Russian Federation.
Fax: +7 (499) 135 5328
The reaction of LnCl3•xTHF with Na(C5H4CH2CH2PPh2) followed by the in situ reaction
with Na2(C14H10) afforded the (C5H4CH2CH2PPh2)Ln(C14H10)L complexes (Ln = Y or Lu
and L = THF or DME). The structure of (C5H4CH2CH2PPh2)Lu(C14H10)(DME) was estabꢀ
lished by Xꢀray diffraction. In solution, there is an equilibrium between the complexes with the
coordinated and uncoordinated phosphorus atom.
Key words: organolanthanide compounds, yttrium, lutetium, dianion, anthracene, substiꢀ
tuted cyclopentadienyl anion.
Scheme 1
Lanthanide complexes with substituted cyclopentaꢀ
dienyl anions are of considerable interest.1 Earlier,2
we have synthesized the lutetium complexes
(C5H4CH2CH2PPh2)2LuCl by the reaction of LuCl3•
•3THF with Na(C5H4CH2CH2PPh2). However, an atꢀ
tempt to apply this method to the synthesis of the monoꢀ
substituted derivative failed due to the redistribution of
the ligands in the monosubstituted complex, which gives
rise to (C5H4CH2CH2PPh2)2LuCl and LuCl3•3THF. We
succeeded in stabilizing the monocyclopentadienyl deꢀ
rivative by introducing the anthracene dianion as the
ligand.
The mono(diphenylphosphinoethyl)cyclopentadiꢀ
enyl complexes (C5H4CH2CH2PPh2)Ln(C14H10)(THF)
(1a,b: Ln = Y (a) and Lu (b)) were synthesized by
the successive addition of solutions of (diphenylꢀ
phosphinoethyl)cyclopentadienylsodium and disodium
anthracene to lanthanide chloride tetrahydrofuranates
(Scheme 1). The complex with dimethoxyethane
(C5H4CH2CH2PPh2)Lu(C14H10)(DME) (2) was prepared
* Dedicated to Academician G. A. Abakumov on the occasion
of his 70th birthday.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1687—1689, September, 2007.
1066ꢀ5285/07/5609ꢀ1749 © 2007 Springer Science+Business Media, Inc.

1750
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 9, September, 2007
Roitershtein et al.
Table 1. Selected geometric parameters of molecule 2
by recrystallization of complex 1b from dimethoxyethane.
The H NMR spectra of all complexes show a singlet at
1
Bond length
d/Å
Bond angle
ω/deg
δ 3.50—3.75 corresponding to the signal for the H(9) and
H(10) atoms of anthracene. The downfield shift of the
signal compared to the signal of disodium anthracene
(δ 1.55)3 is indicative of the coordination of the anthracene
dianion to the Lu3+ cation.4 The 31P NMR spectrum of
the complex with THF (1b) shows an intense signal at
δ –12.0 and a weaker signal at δ –18.5. The downfield
shift of the signal with respect to the signal of the free
ligand (δ –15) gives evidence for the coordination of the
phosphorus atom to the lanthanide atom.2 Apparently,
the complex with the coordinated phosphorus atom is
characterized by the signal at δ –12.0. The signal at δ –18.5
is assigned to the complex with uncoordinated phosphoꢀ
rus, in which the vacant site in the coordination sphere
is occupied by the second tetrahydrofuran molecule
(Scheme 2). The spectrum of the complex with DME (2)
also shows two signals at δ –12.0 and –18.7, but the
intensity ratio is inverse. Therefore, the complex with the
uncoordinated phosphorus atom prevails in dimethoxyꢀ
ethane. This can be attributed to the stronger coordinaꢀ
tion of dimethoxyethane to the lanthanide atoms comꢀ
pared to tetrahydrofuran. To confirm this assumption,
compound 2 was studied by Xꢀray diffraction. Accordꢀ
ing to the Xꢀray diffraction data, the lutetium cation is
coordinated by the cyclopentadienyl fragment of the
(C5H4CH2CH2PPh2)– anion, the anthracene dianion,
and one dimethoxyethane molecule (Fig. 1). The second
DME molecule is included in the crystal lattice. There
are no short contacts between the phosphine fragment of
the (C5H4CH2CH2PPh2)– anion and the lutetium atom.
The average Lu—C distance in the anthracene dianion
is 2.417 Å; in the cyclopentadienyl fragment, these disꢀ
tances are in the range of 2.576—2.620 Å (Table 1). The
Lu—Cantr distances are shorter, on the average, by 0.03 Å,
and the Lu—CCp distances are longer, on the average, by
0.15 Å compared to the corresponding distances in
(C5H5)Lu(C14H10)(THF)2.4 Presumably, this may be parꢀ
tially associated with a weakening of the coordination of
the cyclopentadienyl fragment due to the presence of the
bulky CH2CH2PPh2 substituent.
Lu(1)—O(2)
Lu(1)—O(1)
Lu(1)—C(9)
Lu(1)—C(10) 2.436(7)
Lu(1)—C(15) 2.620(7)
Lu(1)—C(16) 2.609(7)
Lu(1)—C(17) 2.599(7)
Lu(1)—C(18) 2.576(7)
Lu(1)—C(19) 2.579(7)
C(9)—C(11)
C(9)—C(14)
C(10)—C(13) 1.472(9)
C(10)—C(12) 1.480(9)
C(11)—C(12) 1.438(9)
C(13)—C(14) 1.436(9)
2.316(5)
2.348(5)
2.399(6)
C(9)—Lu(1)—C(10)
C(11)—C(9)—C(14)
C(13)—C(10)—C(12) 115.7(6)
C(12)—C(11)—C(9) 116.9(6)
C(11)—C(12)—C(10) 117.7(6)
C(14)—C(13)—C(10) 116.7(6)
C(13)—C(14)—C(9)
O(2)—Lu(1)—O(1)
O(1)—Lu(1)—C(9)
O(2)—Lu(1)—C(9)
O(1)—Lu(1)—C(10)
O(2)—Lu(1)—C(10)
70.5(2)
116.0(6)
118.1(6)
68.51(17)
132.0(2)
87.6(2)
90.8(2)
126.7(2)
1.466(9)
1.470(9)
Scheme 2
To summarize, we synthesized and characterized the
(C5H4CH2CH2PPh2)Ln(C14H10)L complexes (Ln = Y
or Lu and L = THF or DME). Studies of their reactivity
and the dynamic processes in solutions of complexes 1a,b
and 2 are presently underway.
C(31)
C(3)
C(32)
C(6) C(7)
C(4)
C(8)
C(30)
Experimental
C(12)
C(5)
C(2)
C(13)
C(1)
C(29)
C(11)
C(9)
C(14)
Since the compounds under study are highly sensitive to
atmospheric oxygen and moisture, all synthetic operations were
carried out in sealed evacuated apparatus. The solvents were
purified according to known procedures.4 Lanthanide chloride
tetrahydrofuranates were synthesized according to a known proꢀ
cedure.5 The 1H and 31P NMR spectra were recorded on Bruker
WMꢀ250, Bruker AMꢀ300, and Bruker DRXꢀ500 instruments.
The metal content in samples was determined by the direct
complexometric titration with Trilon B using the Xylenol Orange
indicator.
C(10)
C(33)
C(28)
Lu(1)
C(27)
C(37)
C(35)
O(1)
P(1)
C(19)
C(20)
C(21)
C(26)
C(25)
O(2)
C(22)
C(23)
C(36)
C(18)
C(34)
C(15)
C(16)
C(17)
C(24)
Fig. 1. Structure of complex 2 (hydrogen atoms are omitted).

Yttrium and lutetium complexes
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 9, September, 2007
1751
Sodium diphenylphosphinoethylcyclopentadienide. The synꢀ
thesis was performed according to the procedure described
earlier for the preparation of KC5H4CH2CH2PPh2(THF).6
A mixture (5.2 mL) of diphenylphosphine (5.62 g, 30.2 mmol)
and anhydrous THF (5 mL) was gradually added to a suspenꢀ
sion of sodium hydride (1.45 g, 60 mmol) in anhydrous THF
(50 mL) cooled to –10 °C under purified argon. The reacꢀ
tion mixture was stirred at room temperature for 1 day until
evolution of hydrogen ceased. The resulting orange solution
of sodium diphenylphosphide was decanted and cooled to 0 °C.
A solution of spiro[2,4]heptaꢀ4,6ꢀdiene (3.33 g, 36.2 mmol)
in anhydrous THF (20 mL) was added. The reaction mixture
was stirred at room temperature for 2 h. The solvent was
removed in vacuo. The product was washed with anhydrous
petroleum ether and recrystallized from THF. The yield of
NaC5H4CH2CH2PPh2(THF) was 3.24 g (35.8%). 1H NMR
(THFꢀd8), δ: 2.40 (m, 2 H, CH2P); 2.75 (m, 2 H, CH2CH2P);
5.66 (m, 4 H, H(2), H(3), H(4), H(5), C5H4); 7.30 (m, 6 H,
Hm, Hp, Ph); 7.50 (m, 4 H, Ho, Ph). 31P NMR (THFꢀd8), δ:
–15.9 (s).
C14H10); 5.42 (m, 2 H, H(3), H(4), C5H4); 5.65 (m, 2 H, H(2),
H(5), C5H4); 6.02 (dd, 4 H, H(1), H(4), H(5), H(8), C14H10);
6.31 (dd, 4 H, H(2), H(3), H(6), H(7), C14H10); 7.33 (m, 6 H,
Hm, Hp, Ph); 7.50 (m, 4 H, Ho, Ph). 31P NMR (THFꢀd8), δ:
–12.0 (br.s), –18.7 (br.m).
Xꢀray diffraction study of complex 2. Crystals of
2
(C37H38LuO2P•C4H10O2) are monoclinic, at 110 K, space
group P21/c, a = 13.969(7) Å, b = 19.356(10) Å, c = 14.648(6) Å,
β = 116.688(13)°, V = 3539(3) Å3, Z = 4, dcalc = 1.522 g cm–3
,
µ(MoKα) = 28.76 cm–1, F(000)= 1648. The intensities of
23057 reflections were measured at 110 K on a Smart 1000 CCD
diffractometer (λ(MoKα) = 0.71072 Å, ωꢀscanning technique,
the scan step was 0.3°, 2θ < 54°), and 7718 independent reflecꢀ
tions were used in the refinement. The experimental data were
processed and merged and the absorption correction was applied
with the use of the SAINT Plus and SADABS programs. The
structure was solved by direct methods and the inspection of
successive electron density maps. The hydrogen atoms were
positioned geometrically. The refinement was carried out
based on F 2 with anisotropic displacement parameters for
hkl
(Diphenylphosphinoethyl)cyclopentadienyllutetium anthraꢀ
cenide tetrahydrofuranate (1b). A 0.80 М solution of sodium
diphenylphosphinoethylcyclopentadienide (1.64 mmol) in THF
(20.5 mL) was added to a suspension of LuCl3•3THF (0.815 g,
1.64 mmol) in anhydrous THF (70 mL). The reaction mixture
was stirred for 10 min. Then a solution of disodium anthracenide
(70 mL), which was prepared according to a known procedure5
from anthracene (0.292 g, 1.4 mmol), was added, and then the
mixture was vigorously stirred for 6 h. The solution was sepaꢀ
rated from the precipitate and evaporated to dryness. The residue
was washed with petroleum ether and recrystallized from THF.
The yield of compound 1b was 0.873 g (75.8%). Found (%):
Lu, 24.51. Calculated (%): Lu, 24.93. 1H NMR (THFꢀd8), δ:
2.53 (m, 2 H, CH2P); 2.58 (m, 2 H, CH2CH2P); 3.50 (s, 2 H,
H(9), H(10), C14H10); 5.41 (m, 2 H, H(3), H(4), C5H4); 5.69
(m, 2 H, H(2), H(5), C5H4); 6.02 (dd, 4 H, H(1), H(4), H(5),
H(8), C14H10); 6.30 (dd, 4 H, H(2), H(3), H(6), H(7), C14H10);
7.36 (m, 6 H, Hm, Hp, Ph); 7.65 (m, 4 H, Ho, Ph). 31P NMR
(THFꢀd8), δ: 12.0 (br.s), –18.5 (br.s).
(Diphenylphosphinoethyl)cyclopentadienylyttrium anthraꢀ
cenide tetrahydrofuranate (1a) was synthesized analogously to
the corresponding lutetium complex. Compound 1a was obꢀ
tained in a yield of 0.759 g (63.5%) from YCl3•2.7THF (0.754 g,
1.94 mmol). Found (%): Y, 22.73. Calculated (%): Y, 22.82.
1H NMR (THFꢀd8), δ: 2.35 (m, 2 H, CH2P); 2.62 (m, 2 H,
CH2CH2P); 3.72 (s, 2 H, H(9), H(10), C14H10); 5.61 (m, 2 H,
H(3), H(4), C5H4); 5.82 (m, 2 H, H(2), H(5), C5H4); 6.10 (dd,
4 H, H(1), H(4), H(5), H(8), C14H10); 6.32 (dd, 4 H, H(2),
H(3), H(6), H(7), C14H10); 7.30 (m, 6 H, Hm, Hp, Ph); 7.48 (m,
4 H, Ho, Ph).
nonhydrogen atoms and isotropic displacement parameters for
hydrogen atoms. The final R factors for 2 were R1 = 0.0464
(based on Fhkl for 4812 reflections with I > 2σ(I )) and
wR2 = 0.1153 (based F 2 for all 7718 reflections), the number
hkl
of variables was 428, GOOF = 1.001. The calculations were
carried out with the use of the SHELXTL 5.10 program package.
This study was financially supported by the Russian
Foundation for Basic Research (Project No. 04ꢀ03ꢀ
32737a).
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(Diphenylphosphinoethyl)cyclopentadienyllutetium anthraꢀ
cenide dimethoxyethoxide (2) was prepared by recrystallization
of 1b from dimethoxyethane. Found (%): Lu, 21.85. Calcuꢀ
lated (%): Lu, 21.60. 1H NMR (THFꢀd8), δ: 2.57 (m, 2 H,
CH2P); 2.70 (m, 2 H, CH2CH2P); 3.60 (s, 2 H, H(9); H(10),
Received December 29, 2006;
in revised form April 9, 2007