Erbium and ytterbium complexes with phosphates and phosphine oxides

Article abstract of DOI:10.1070/MC2004v014n03ABEH001894

The new complexes of erbium and ytterbium with amine, phosphate and phosphine oxide ligands Ln(NH₂R)₃Cl₃, Ln[O=P(NMe₂)₂NHR]₃Cl₃, Ln[O=P(OPh)₂NHR]₃Cl₃

Full text of DOI:10.1070/MC2004v014n03ABEH001894

, 2004, 14(3), 109–111
Erbium and ytterbium complexes with phosphates and phosphine oxides
Boris A. Bushuk,a Sergei B. Bushuk,a Nadezhda F. Cherepennikova,b William E. Douglas,c Georgii K. Fukin,b
Iliya S. Grigoriev,b Larisa G. Klapshina,b Arie van der Leed and Vladimir V. Semenov*b
a B. I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, 220072 Minsk, Belarus.
E-mail: bushuk@dragon.bas-net.by
b G. A. Razuvaev Institute of Organometallic Chemistry, Russian Academy of Sciences, 603950 Nizhnii Novgorod, Russian Federation.
Fax: +7 8312 12 7497; e-mail: vvsemenov@imoc.sinn.ru
c Laboratoire de Chimie Moléculaire et Organisation du Solide, CNRS UMR 5637, Université Montpellier II,
34095 Montpellier cedex 5, France. Fax: 33 467 143 852; e-mail: douglas@univ-montp2.fr
d Institut Européen de Membranes, UMR CNRS 5635, CC047, Université Montpellier II, 34095, Montpellier cedex 5, France.
E-mail: vdlee@pollux.iemm.univ-montp2.fr
DOI: 10.1070/MC2004v014n03ABEH001894
The new complexes of erbium and ytterbium with amine, phosphate and phosphine oxide ligands Ln(NH2R)3Cl3,
Ln[O=P(NMe2)2NHR]3Cl3, Ln[O=P(OPh)2NHR]3Cl3, [R=CH2CH2CH2Si(OEt)3], Ln[O=P(OPh)3]3Cl3, Ln[O=P(CH2CH2CF3)3]3Cl3
and Ln[O=P(CH=CHPh)3]3Cl3 have been synthesised, and their absorption spectra have been measured in both films and solutions.
Many organometallic compounds and complexes of lanthanides
exhibit extraordinarily high photo- and electroluminescence
properties. For this reason, lanthanide-doped materials are very
promising as gain media for the generation and amplification of
intense light pulses.1–4 For practical applications of lanthanide
metal complexes in optoelectronic devices, further development
should be focused on obtaining easier fabrication at lower
cost, together with better mechanical and thermal stability of
the resulting materials. Thus, the preparation of stable rare eath
metal complexes incorporated into a solid organic or organo-
silicon polymer matrix is very challenging.1,2 Here we report
the synthesis of three new phosphorous- and fluorine-containing
ligands giving stable complexes with erbium and ytterbium, and
the incorporation of these complexes into film-forming polymer
composites. The preparation of high optical quality thermo-
stable films doped with Er or Yb cations is also described. The
absorption spectra of the Er and Yb complexes are reported.
New ligands 2, 3 and 5 were prepared. The procedures
described previously5,6 were used for the syntheses of tri-
phenylphosphate O=P(OPh)3 4 and tris(styryl)phosphine oxide
O=P(CH=CHPh)3 6. Bis(dimethylamido)(3-triethoxysiliyl-
propylamido)phosphate O=P(NMe2)2NHCH2CH2CH2Si(OEt)3
2 was synthesised by the reaction of 3-aminopropyltriethoxy-
silane NH2CH2CH2CH2Si(OEt)3 1 (APTES) with bis(dimethyl-
amido)chlorophosphate (Me2N)2P(O)Cl. The interaction of
APTES with diphenylphosphate (PhO)2P(O)Cl gives diphenyl-
(3-triethoxysilylpropylamido)phosphate O=P(OPh)2NHCH2-
CH2CH2Si(OEt)3 3. Tris(3,3,3-trifluoropropyl)phosphine oxide
O=P(CH2CH2CF3)3 5 was synthesised by the interaction of
3 equiv. of 3,3,3-triflouropropylmagnesium chloride F3CCH2-
CH2MgCl with phosphorous chloroxide in ether.
The interaction of dried erbium(III) or ytterbium(III) chloride
with amine 1, phosphates 2–4 or phosphine oxides 5, 6 in
diethyl ether, chloroform and acetonitrile afforded 11 new
lanthanide complexes: Er(NH2R)3Cl3 7, Er[O=P(NMe2)2-
NHR]3Cl3 8,† Er[O=P(OPh)2NHR]3Cl3 9, Er[O=P(OPh)3]3Cl3
10, Er[O=P(CH2CH2CF3)3]3Cl3 11, Er[O=P(CH=CHPh)3]3Cl3
12, Yb(NH2R)3Cl3 13, Yb[O=P(OPh)2NHR]3Cl3 14,
Yb[O=P(OPh)3]3Cl3 15, Yb[O=P(CH2CH2CF3)3]3Cl3 16,
Yb[O=P(CH=CHPh)3]3Cl3 17, R=CH2CH2CH2Si(OEt)3. Com-
pounds 7–10 and 13–15 are viscous liquids, whereas 11, 12, 16
and 17 are solids of differing stability towards atmospheric
moisture. It is well known14 that rare earth metal complexes are
readily hydrolysed by water. The H2O molecule causes strong
†
Bis(dimethylamido)(3-triethoxysilylpropylamido)phosphate 2. A solu-
tion of APTES (11.4 g, 0.052 mol) in 50 ml of toluene was added drop-
by-drop to a solution of (Me2N)2P(O)Cl (8.8 g, 0.052 mol) and Et3N
(5.25 g, 0.052 mol) in 50 ml toluene with stirring. The reaction mixture
was heated for 10 h at 100–110 °C followed by filtering and vacuum
distillation to afford 4.2 g (23%) of ligand 2 [colourless transparent
1
liquid, bp 120–123 °C (0.3 Torr)]. H NMR (200 MHz, CDCl3) d: 0.45,
0.49, 0.51, 0.53 (q, 2H, CH2Si), 0.92 (s, NH), 1.04, 1.05, 1.08, 1.09,
1.11, 1.12 (m, 9H, Me–CH2OSi), 1.43, 1.47, 1.50 (t, 2H, CH2–CH2Si),
2.50, 2.51, 2.54, 2.56 (q, 12H, MeN), 2.68, 2.71, 2.73, 2.75, 2.79 (m,
2H, NCH2), 3.62, 3.66, 3.69, 3.73, 3.75, 3.76, 3.79 (m, 6H, CH2OSi).
IR (n/cm–1): 3200, 2970, 2920, 2870, 2800, 1450, 1390, 1290, 1200,
1170, 1110, 1080, 980, 955, 770, 740, 660, 470. Found (%): C, 43.21; H,
10.06; P, 9.03; Si, 8.05. Calc. for. C13H34N3O4PSi (%): C, 43.92; H,
9.64; P, 8.72; Si, 7.90.
Compound 3 was synthesised in an analogous way to that used for 2.
Tris(3,3,3-trifluoropropyl)phosphine oxide 5. Mp 193–195 °C. 1H NMR
(200 MHz, CDCl3) d: 2.01, 2.03, 2.04, 2.07, 2.09 (m, 6H, CH2P), 2.37,
2.40, 2.42, 2.43, 2.44, 2.46, 2.47, 2.48, 2.49, 2.50 (m, 6H, CH2C).
31P NMR (200 MHz, CD3CN) d: 45.17. IR (n/cm–1): 1305, 1255, 1230,
1200, 1150, 1125, 1110, 1065, 1020, 925, 835, 785, 640, 615, 550, 440,
375, 355. Found (%): C, 31.94; H, 3.90. Calc. for. C9H12F9OP (%): C,
31.98; H, 3.58.
Compounds 2 and 3 are colourless viscous liquids, and 4–6
are colourless crystalline solids relatively stable to oxygen and
moisture.† The crystal structure and main geometrical parameters
of phosphine oxides 5 and 6 are shown in Figure 1.‡
1
Tris(styryl)phosphine oxide 6. H NMR (200 MHz, CDCl3) d: 6.53,
Needle crystals suitable for single X-ray analysis were grown
from hot acetonitrile (5) or hot toluene (6). The P atoms have
a distorted tetrahedral coordination. The bond angles for the
P atoms vary in the ranges 105.53(9)–113.17(8)° for 5 and
104.38(5)–114.18(4)° for 6. The P–O distances are 1.494(2)
and 1.485(2) Å for 5 and 6, respectively. The corresponding
distance for the other compounds is 1.489 Å.11 The P–C distance
for 5 [1.801(2) Å] is longer than that for 6 [1.781(1) Å]. The
C(1)–C(2) distance [1.335(2) Å] in 6 lies in the range of C=C
distances [1.294–1.345 Å]11 for organic molecules. The C(2)–
C(3) distance in 6 is 1.471(2) Å, which is very close to that in
molecules containing conjugated C=C–Car fragments (1.470 Å).11
The styrene ligands in 6 have a trans conformation. The
angle between the C(1)H(1)C(2)H(2) and C(3–8) planes is
34.1° being significantly bigger than analogous angles in
Ph2PCH=CHPh (9.4°)12 and (OH)2(O=)PCH=CHPh (13.5°).13
6.61, 6.64, 6.72 (q, 6H, CH=CH), 7.37, 7.39, 7.40, 7.41, 7.42 (m, 6H,
CH=CH–P), 7.50, 7.52, 7.53, 7.55, 7.57, 7.60 (m, 15H, Ph). 31P NMR
(200 MHz, CDCl3) d: 20.90. IR (n/cm–1): 1610, 1575, 1230, 1170, 980,
835, 800, 740, 690, 600, 505, 460. UV [l/nm (e/dm3 mol–1 cm–1)]: 214
(sh.), 220 (sh.), 281 (42000).
Trichloro-tris[bis(dimethylamido)(3-triethoxysilylpropylamido)phos-
phate]erbium(III) 8. A solution of amidophosphate 2 (1.82 g, 0.0051 mol)
in diethyl ether (5 ml) was dropped onto ErCl3 (0.47 g, 0.0017 mol) in
vacuo resulting in an exothermal reaction accompanied by the dissolu-
tion of the erbium chloride. The solid product was separated by centri-
fuging and the diethyl ether was removed in vacuo affording 1.66 g of
complex 8 (yield 73%, viscous pink liquid). IR (n/cm–1): 3250, 2970,
2920, 2875, 2800, 1480, 1450, 1390, 1300, 1270, 1210, 1170, 1130,
1110, 1060, 1000, 990, 955, 770, 755, 690, 475. Found (%): C, 35.38;
H, 8.04; Cl, 7.24; Er, 12.75; P, 7.08; Si, 6.42. Calc. for
C39H102Cl3ErN9O12P3Si3 (%): C, 34.95; H, 7.67; Cl, 7.95; Er, 12.48; P,
6.94; Si, 6.29. Complexes 9, 10, 14 and 15 were obtained analogously.
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, 2004, 14(3), 109–111
Table 1 Absorption spectra [n/cm–1 (e/dm3 mol–1 cm–1)] of erbium complexes 7–9, 11 and 12.a
Transition
7
8
9
11
12
Er3+ aqua cation
4I15/2 ® 2K15/2
4I15/2 ® 4G11/2
4I15/2 ® 4F7/2
4I15/2 ® 2H11/2
4I15/2 ® 4F9/2
4I15/2 ® 4I9/2
4I15/2 ® 4I11/2
4I15/2 ® 4I13/2
27400 (2.63)
26400 (18.42)
20600 (2.63)
19200 (11.58)
15400 (2.11)
12500 (0.35)
10200 (1.06)
6540 (2.83)
27500
26550 (15.73)
20550
19300 (6.11)
15400
27400
26400 (8.25)
20400 (1.68)
19100 (5.73)
15250 (1.96)
12200 (0.98)
26500 (16.08)
19210 (9.46)
26370 (6.90)
20530 (2.03)
19120 (3.28)
15.326 (2.04)
19230 (15.58)
15310 (1.25)
11330 (4.90)
9850 (9.02)
10250 (0.82)
6530 (2.34)
a7–9, films on silica; 11, an acetonitrile solution; 12, a chloroform solution.
luminescence quenching.15 We monitored the concentration of
hydroxyl groups by IR spectroscopy, which showed that the
trend to hydration depends on the ligand and increases in the
order 6 < 2 < 3 < 1 < 5 < 4. The hydroxyl bands at 3300 and
1600 cm–1 are absent for complexes 8, 9, 12, 14, 17 with
triamidophospate, diphenylamidophosphate and styrylphosphine
oxide ligands and are very weak for complexes 7, 11, 13, 16
with amine and trifluoropropylphosphine oxide ligands. How-
ever, the bands are quite intense for complexes 10, 15 with the
triphenylphosphate ligand. Note that the addition of free tri-
phenyl phosphate decreases the hydroxyl band intensities for 10
and 15.
F(6)
(a)
F(7)
C(5)
F(8)
APTES is an excellent precursor for the production of sol–
gel films. We found that this useful feature is transferred to
metal complexes 7–9, 13 and 14 synthesised from ligands 2
and 3. High optical quality sol–gel films were obtained from the
compositions containing the amidophosphate erbium complex,
oligodimethylsiloxane-α,ω-diols HO(SiMe2O)nH (n = 3–7) and
trifunctional organoalkoxysilanes [MeSi(OMe)3, PhSi(OMe)3,
NH2CH2CH2CH2Si(OEt)3] with a weight ratio from 1:0.5:0.2
up to 1:1:0.5. The films are formed within 5–15 h and they
remained transparent up to 200 °C.
C(4)
C(3)
O(2)
P(1)
The electronic absorption spectra for the complexes were
measured in films of thickness 70–170 µm for 7–9, and 14 and
in acetonitrile or chloroform solutions in the case of 11 or 12,
respectively (Table 1). The series of narrow bands in the region
28000–15000 cm–1 corresponds to f–f transitions in Er3+. Their
position depends very slightly on the ligand (the variation
being no more than 200 cm–1) and no splitting or broadening is
observed. However, an increase in the value of e by a factor of
2.7–3.5 (relative to the erbium aqua cation15) is observed for
(b)
the supersensitive transition bands at 26370 (4I15/2 ® 4G11/2
)
and 19120 cm–1 (4I15/2 ® 2H11/2). The strongest absorption was
revealed for erbium amine complex 7. The narrow bands arising
2
4
4
P(1)
O(1)
from the f–f transitions to the exited levels H11/2, F9/2, I9/2
4
and I11/2 were revealed in the absorption spectrum of erbium
C(2)
complex 12 with the tris(styryl)phosphine oxide ligand in the
region 500–1100 nm (20000–9090 cm–1). The region 250–420 nm
(40000–23800 cm–1) is occupied by an intense absorption
C(3)
C(1)
C(8)
C(4)
C(5)
band of ligand 6. The I15/2 ® 4I9/2 and I15/2 ® 4I11/2 transition
absorption bands also have high intensities and in comparison
with the corresponding transitions in the amide and phenyl-
phosphate complexes are shifted to longer wavelengths. The
absorption spectrum of ytterbium complex 14 was measured in
the region 50000–12000 cm–1. Only the ligand absorption band
(triplet at 38900, 38100 and 37200 cm–1) was observed.15
The near-IR absorption spectra were measured for films
prepared from amine 7 and amidophosphate 8 complexes,
siloxanediols and phenyltrimethoxysilane (all the films con-
tained the same concentration of erbium). The spectra of the
complexes are very similar in the region 800–2000 nm (12500–
5000 cm–1) in spite of the essential difference in the chemical
structures of the ligands. The transition 4I15/2 ® 4I13/2 at 1530 nm
(6530 cm–1) overlaps with the absorption of the N–H and O–H
bonds. Note that the degree of the overlap is greater for amine
complex 7 containing a higher concentration of N–H groups.
4
4
C(7)
C(6)
Figure 1 Molecular structures of compounds (a) 5 and (b) 6. Important
distances (Å) and angles (°) for 5: P(1)–C(3) 1.801(2), P(1)–O(2) 1.494(2),
C(5)–F(8) 1.341(3), C(5)–F(7) 1.335(3), C(5)–F(6) 1.340(3); C(3)–P(1)–
O(2) 113.17(8), C(3)–P(1)–C(3) (2 – x + y, 1 – x, z) 105.53(9) and for 6:
P(1)–O(1) 1.485(2), P(1)–C(1) 1.781(1), C(1)–C(2) 1.335(2), C(2)–C(3)
1.471(2); O(1)–P(1)–C(1) 114.18(4), C(1)–P(1)–C(1) (–x + y + 1, –x + 1, z)
104.38(5).
C9H12F9OP 5: trigonal, a = 15.170(2), c = 9.979(1) Å, V = 1988.8(4) Å3,
space group R3c, Z = 6, m = 0.307 mm–1, number of reflections measured,
12831; number of independent reflections, 1440; Rint = 0.05, Rall
= 0.0575, wRall = 0.0568. Structure solution by direct methods7 and
structure refinement using CRYSTALS.8
‡
=
C24H21OP 6: trigonal, a = 18.0896(8), c = 5.0536(4) Å, V = 1432.2(1) Å3,
space group R3, Z = 3, m = 0.153 mm–1, number of reflections measured,
3410; number of independent reflections, 1644; Rint = 0.02, Rall = 0.0363,
wRall = 0.0876. Structure solution by direct methods SHELXS-979 and
structure refinement using SHELXL-97.10
Atomic coordinates, bond lengths, bond angles and thermal param-
eters have been deposited at the Cambridge Crystallographic Data Centre
(CCDC). These data can be obtained free of charge via www.ccdc.cam.uk/
conts/retrieving.html (or from the CCDC, 12 Union Road, Cambridge
CB2 1EZ, UK; fax: +44 1223 336 033; or deposit@ccdc.cam.ac.uk).
Any request to the CCDC for data should quote the full literature citation
and CCDC reference numbers 229549 (for 5) and 230016 (for 6). For
details, see ‘Notice to Authors’, Mendeleev Commun., Issue 1, 2004.
4
At the same time, the transition I15/2 ® 4I11/2 at 975 nm
(10250 cm–1) is almost free from overlap with the bands of the
overtone absorption for the C–H bonds normally observed in
the region 850–950 nm (11760–10530 cm–1).
This study was supported by the Russian Foundation for
Basic Research (grant no. 02-03-32165), the President of the
Russian Federation (grant no. 1652.2003.3) and the RAS
Nanotechnology Programme.
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, 2004, 14(3), 109–111
11 F. H. Allen, O. Kennard, D. G. Vatson, L. Brammer, A. G. Orpen and
R. Taylor, J. Chem. Soc., Perkin Trans. 2, 1987, 12, 51.
12 M. Taillefer, H. J. Cristau, A. Fruchier and V. Vicente, J. Organomet.
Chem., 2001, 624, 307.
13 V. V. Tkachev, L. O. Atovmyan, B. V. Timokhin, O. A. Bragina, G. V.
Ratovskii and L. M. Sergienko, Zh. Strukt. Khim., 1986, 27, 121 [J.
Struct. Chem. (Engl. Transl.), 1986, 27, 443].
References
1
2
3
K. Kuriki, Y. Koike and Y. Okamoto, Chem. Rev., 2002, 102, 2347.
U. Mitschke and P. Bauerle, J. Mater. Chem., 2000, 10, 1471.
A. V. Vannikov, Ross. Khim. Zh. (Zh. Ross. Khim. Ob-va im.
D. I. Mendeleeva), 2001, 45, 41 (in Russian).
4
5
S. Heer, O. Lehman, M. Haase and H. U. Gudel, Angew. Chem., Int.
Ed. Engl., 2003, 42, 3179.
E. E. Nifant’ev, Khimiya fosfororganicheskikh soedinenii (Chemistry
of Organophosphorus Compounds), Izdatel’stvo Moskovskogo Univer-
siteta, Moscow, 1971, p. 154 (in Russian).
14 J. H. Forsberg, Coord. Chem. Rev., 1973, 10, 195.
15 N. C. Poluektov, L. I. Kononenko, N. P. Efryushina and S. V. Beltyukova,
Spektrofotometricheskie i luminestsentnye metody opredeleniya lan-
tanoidov (Spectrophotometrical and Luminescence Methods of a
Lanthanoid Determination), Naukova Dumka, Kiev, 1989 (in Russian).
6
7
8
V. S. Galeev and Ya. A. Levin, Zh. Obshch. Khim., 1972, 42, 1496
[J. Gen. Chem. USSR (Engl. Transl.), 1972, 42, 1487].
A. Altomare, G. Cascarano, G. Giacovazzo, A. Guagliardi, M. C. Burla,
G. Polidori and M. Camalli, J. Appl. Crystallogr., 1994, 27, 435.
D. J. Watkin, C. K. Prout, J. R. Carruthers, P. W. Betteridge and R. I.
Cooper, CRYSTALS, Chemical Crystallography Laboratory, Oxford,
2001, Issue 11.
9
G. M. Sheldrick, SHELXS-97 Program for the Solution of Crystal
Structures, Universität Göttingen, 1990.
10 G. M. Sheldrick, SHELXL-97 Program for the Refinement of Crystal
Structures, Universität Göttingen, 1997.
Received: 22nd January 2004; Com. 04/2220
– 111 –