Inner and Outer Sphere Coordination of Tricyclohexylphosphine oxide with Lanthanide Bromides Allen Bowden 1 , Anthony M.J.Lees 2* and Andrew W.G.Platt 2* 1. Department of Chemistry and Analytical Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6BT, UK 2. School of Sciences, Staffordshire University, Leek Road, Stoke-on-Trent, ST4 2DF, UK * Corresponding authors, E-Mail addresses [email protected], [email protected]Abstract Complexes of lanthanide bromides with tricyclohexylphosphine oxide (Cy 3 PO) form three distinct structural classes. Type I complexes LnBr 3 (Cy 3 PO) 3 have been structurally characterised for Ln = La, Pr, Nd, Gd and Ho and are molecular 6 coordinate with a distorted meridional octahedral arrangement. Type II complexes are based on pentagonal bipyramidal [Ln(Cy 3 PO) n (H 2 O) 5 ] 3+ structures and fall into three subsets; n = 2 and 3 have been isolated for Ln = Lu and n = 4 with Ln = La, Dy, Er and Yb. The structures of [Lu(Cy 3 PO) 2 (H 2 O) 5 ]Br 3 ·2EtOH and [Ln(Cy 3 PO) 2 (H 2 O) 5 ]Br 3 (Ln = Dy, Er, Yb) have been determined. When n = 2 both ligands are directly coordinated to the metal whilst complexes in which n = 4 have two ligands bonded to the metal and two hydrogen bonded to the coordinated water molecules. Analysis of the bond distances shows that the lanthanide contraction accounts for about 99% of the observed 1
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Inner and Outer Sphere Coordination of Tricyclohexylphosphine oxide with Lanthanide Bromides
Allen Bowden1, Anthony M.J.Lees2* and Andrew W.G.Platt2*
1. Department of Chemistry and Analytical Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6BT, UK2. School of Sciences, Staffordshire University, Leek Road, Stoke-on-Trent, ST4 2DF, UK* Corresponding authors, E-Mail addresses [email protected], [email protected]
AbstractComplexes of lanthanide bromides with tricyclohexylphosphine oxide (Cy3PO) form three
distinct structural classes. Type I complexes LnBr3(Cy3PO)3 have been structurally
characterised for Ln = La, Pr, Nd, Gd and Ho and are molecular 6 coordinate with a distorted
meridional octahedral arrangement. Type II complexes are based on pentagonal bipyramidal
[Ln(Cy3PO)n(H2O)5]3+ structures and fall into three subsets; n = 2 and 3 have been isolated for
Ln = Lu and n = 4 with Ln = La, Dy, Er and Yb. The structures of
[Lu(Cy3PO)2(H2O)5]Br3·2EtOH and [Ln(Cy3PO)2(H2O)5]Br3 (Ln = Dy, Er, Yb) have been
determined. When n = 2 both ligands are directly coordinated to the metal whilst complexes
in which n = 4 have two ligands bonded to the metal and two hydrogen bonded to the
coordinated water molecules. Analysis of the bond distances shows that the lanthanide
contraction accounts for about 99% of the observed trends. The infrared spectra of the
complexes give a good means of identifying the structural types produced. 31P NMR show
that the Type I complexes are fluxional in solution and that the Type II complexes undergo
ligand exchange between metal and H-bonded ligands. Analysis of the lanthanide induced
shifts indicates that the Type II complexes are isostructural in solution.
Introduction
The coordination complexes formed between lanthanide metal ions and phosphine oxides
have been studied since the late 1960s [1]. Continued interest in this area comes as a result of
the use of phosphine oxides in the solvent extraction in nuclear fuels reprocessing [2]. The
PrBr3·6H2O (0.25 g, 0.51 mmol) and Cy3PO (0.66 g, 2.24 mmol) in 4.0 g hot ethanol gave a
small quantity of green crystals in the hot solution. These were removed, washed with a little
cold ethanol and air dried giving 0.06 g. Slow evaporation gave a further crop of green
crystals 0.30 g (55%) with an identical infrared spectrum.
IR(ATR)/cm-1: OH 3150 (w), PO1085 (s), 1073(m)
Analysis for PrBr3(Cy3PO)3·0.5H2O : required (found) C50.71(50.79) H 7.88(7.97)
GdBr3(Cy3PO)3·0.5H2O
GdBr3·6H2O (0.40 g, 0.80 mmol) and Cy3PO (0.56 g, 1.89mmol) in 7.5 g hot ethanol led to
the formation of a small quantity of colourless crystals (0.04 g). On standing a further crop of
colourless crystals (0.21 g, 30%) were obtained.
IR(ATR)/cm-1: OH 3230 (w) PO1095 (s), 1073(m)
Analysis for GdBr3(Cy3PO)3·0.5H2O required (found) C50.07(49.71) H 7.78(7.83)
[Dy(Cy3PO)2(H2O)5](Cy3PO)2Br3·H2O
DyBr3·6H2O (0.32 g 0.63 mmol) and Cy3PO (0.72 g 2.44 mmol) in 11 g hot ethanol on slow
evaporation (21 days) gave a small quantity of colourless crystals (0.09 g, 1%)
IR(ATR)/cm-1:OH 3170 (w,br) PO1094 (s), 1079(m)
Analysis required for [Dy(Cy3PO)2(H2O)5](Cy3PO)2Br3·H2O (found) C51.02(50.96) H
8.56(8.78)
[Er(Cy3PO)2(H2O)5](Cy3PO)2Br3·4H2O
ErBr3·7H2O (0.36 g, 0.70 mmol) and Cy3PO (0.34 g1.13 mmol) in 12.0 g hot ethanol gave a
small quantity of pink crystals on standing overnight and a further 0.37 g (75%) on slow
evaporation. The infrared spectra of both batches were identical.
14
IR(ATR)/cm-1: OH 3219(m, br), OH 1633 (w), PO1100 (s)
Analysis required for [Er(Cy3PO)2(H2O)5](Cy3PO)2Br3·4H2O (found) C49.28(49.25) H
8.62(8.26)
[Yb(Cy3PO)2(H2O)5](Cy3PO)2Br3·H2O
YbBr3·6H2O (0.28 g 0.41 mmol) and Cy3PO (0.51 g 1.74 mmol) in 10 g hot ethanol gave 0.25
g colourless crystals on standing overnight. A further 0.36 g (51%) were obtained from the
filtrate by slow evaporation. The infrared spectra of both batches were identical.
IR(ATR)/cm-1:OH 3180 (m), PO 1118(m), 1102(s)
Analysis required for [Yb(Cy3PO)2(H2O)5](Cy3PO)2Br3.H2O (found) C50.70(49.85) H
8.51(8.67)
[Lu(Cy3PO)2(H2O)5]Br3
LuBr3·7H2O (0.37g, 0.68mmol) and Cy3PO (0.45g, 1.50 mmol) in 4.8 g hot ethanol gave a
colourless crystalline solid on standing overnight, 0.44 g (59%)
IR(ATR)/cm-1: OH 3219(m, br), OH 1617 (w), PO1100 (s)
Analysis for [Lu(Cy3PO)2(H2O)5]Br3: required (found) C39.39(39.46) H 6.98(7.44)
[Lu(Cy3PO)2(H2O)5](Cy3PO)Br3
The filtrate from the above on standing yielded a crop of colourless crystals of
[Lu(Cy3PO)2(H2O)5](Cy3PO)Br3, 0.20 g (24%)
IR(ATR)/cm-1: OH 3173(m, br), OH 1643 (w), PO 1120 (m)1101 (s)
Analysis for [Lu(Cy3PO)2(H2O)5](Cy3PO)Br3: required (found) C46.53(46.63) H 7.88(8.07)
15
References
[1] a) D. R. Cousins, F. A. Hart, J. Inorg. Nucl. Chem. 29 (1967) 1745-1757; b) D. R. Cousins, F. A. Hart, J. Inorg. Nucl. Chem. 30 (1968) 3009-3015.
[2] J. V. Kingston, E. M. Krankovits, R. J. Magee, Inorg. Nucl. Chem. Lett. 5 (1969) 485-489.
[3] C. Jones, P. C. Junk, M. K. Smith, R. C. Thomas, Z. Anorg. Allg. Chem. 626 (2000) 2491-2497.
[4] C. C. Hines, C. B. Bauer, R. D. Rogers, New J. Chem. 31 (2007) 762-769.
[5] M. D. Brown, W. Levason, D. C. Murray, M. C. Popham, G. Reid, M. Webster, J. Chem. Soc. Dalton Trans. (2003) 857-865.
[6] a) D. Parker, H. Puschmann, A. S. Batsanov, K. Senanayake, Inorg. Chem. 42 (2003) 8646-8651; b) K. I. Hardcastle, M. Botta, M. Fasano, G. Digilio, Eur. J. Inorg. Chem. 5 (2000) 971-977; c) A. Barge, M. Botta, D. Parker, H. Puschmann, Chem. Commun. 12 (2003) 1386-1387.
[7] a) S. Ishiguro, Y. Umebayashi, M. Komiya, Coord. Chem. Rev.226 (2002) 103-111; b) S. Ishiguro, Y. Umebayashi, R. Kanzaki, Anal. Sci.20 (2004) 415-421.
[8] G. R. Choppin, J. Alloy. Compd. 249 (1997) 9-13.
[9] a) M. J. Glazier, W. Levason, M. L. Matthews, P. L. Thornton, M. Webster, Inorg. Chim. Acta 357 (2004) 1083-1091; b) N. J. Hill, L-S Leung, W. Levason, M. Webster; Acta Cryst. C58 (2002) m295-m296.
[10] N. J. Hill, W. Levason, M. C. Popham, G. Reid, M. Webster, Polyhedron 21 (2002) 445-455.
[11] A. Bowden, A. W. G. Platt, K. Singh, R. Townsend, Inorg. Chim. Acta 363 (2010) 243-249.
[12] J-C. Berthet, M. Nierlich, M. Ephritikhine, Polyhedron 22 (2003) 3475-3482.
[13] A. M. J. Lees, A. W. G. Platt, Polyhedron 67 (2014) 368-372.
[14] L. I. Semenova, P. C. Junk, B. W. Skelton, A. H. White, Aust. J. Chem.52 (1999) 531-538.
[15] A. P. Hunter, A. M. J. Lees, A. W. G. Platt, Polyhedron 26 (2007) 4865-4876.
[16] F. G. Moers, P. J. W. M. Müskens, J. Francot, J. Inorg. Nucl. Chem.41 (1979) 759-760.
[17] G. Bandoli, D. A. Clemente, G. Deganelli, G. Carturan, P. Uguaglia, U. Belluco, J. Organomet. Chem. 71 (1974) 125-133.
16
[18] D. Lundberg, I. Persson, L. Eriksson, P. D’Angelo, S. De Panfilis, Inorg. Chem. 49 (2010) 4420-4432.
[19] H. P. Lane, S. M. Godfrey, C. A. McCauliffe, R. G. Prochard, J. Chem. Soc. Dalton Trans. (1994) 3249-3256.
[20] E. M. Godfrey, N. Ho, C. A. McCauliffe, R. G. Prichard, Angew. Chem. Int. Ed. 35 (1996) 2344-2346.
[21] A. A. Boraei, V-V. DuMont, F. Rulhe, P. G. Jones, Acta Cryst. C58 (2002) o318-o320.
[22] A. R. Kennedey, S. W. Sloss, M. D. Spicer, Acta Cryst. C53 (1997) 292-293.
[23] S. Alvarez, P. Alemany, D. Casanova, J. Cirera, M. Llunell, D. Avnir, Coord. Chem. Rev. 249 (2005) 1693-1708.
[24] M. Llunell, D. Casanova, J. Cirera, P. Alemany, S. Alvarez, SHAPE – Program for the Stereochemical Analysis of Molecular Fragments by Means of Continuous Shape Measures and Associated Tools, Version 2.1, University of Barcelona, Spain, 2013
[25] D. Casanova, P. Alemany, J. Bofill, S. Alvarez, Chem. Eur. J. 9 (2003) 1281-1295.
[26] a) A. Bowden, S. J. Coles, M. B. Pitak, A. W. G. Platt, Polyhedron 68 (2014) 258-264; b) A. Bowden, K. Singh, A. W. G. Platt, Polyhedron 42 (2012) 30-35; c) A. Bowden, P. N. Horton, A. W. G. Platt, Inorg. Chem.50 (2011) 2553-2561.
[27] N. Ouali, J-P Rivera, D. Chapon, P. Delange, C. Piguet, Inorg. Chem. 43 (2004) 1517-1529.
[28] C. F. G. C. Geraldes, S. R. Zhang, A. D. Sherry, Inorg. Chim. Acta 357 (2004) 381-395.
[29] P. Rubini, C. Ben Nasr, L. Rodehüser, J-J. Delpuech, Magn. Reson. Chem. 25 (1987) 609-618.
[30] DENZO - Data collection and processing software: Z. Otwinowski, W. Minor in Methods in Enzymology, Vol 276; Macromolecular Crystallography, part A, (Eds.: C. W. Carter, Jr, R. M. Sweet), Academic Press, London, 1997, pp. 307-326.
[31] COLLECT - Data collection software, R. Hooft, Nonius B.V., 1998.
[32] Unit cell determination using DirAx: a) A. J. M. Duisenberg, J. Appl. Crystallogr. 25 (1992) 92-96; b) A. J. M. Duisenberg, R. W. W. Hooft, A. M. M. Schreurs, J. Kroon, J. Appl. Crystallogr. 33 (2000) 893-898.
[33] Absorption correction: G. M. Sheldrick, SADABS. Version 2007/2. Bruker AXS Inc., Madison, Wisconsin, USA.
[34] SHELX-2013: G. M. Sheldrick, Acta Cryst. A64 (2008) 112-122.
17
[35] WinGX: L. J. Farrugia, J. Appl. Crystallogr. 45 (2012) 849-854.
[36] SQUEEZE: P. van der Sluis, A. L. Spek, Acta Crystallogr., Sect. A: Found. Crystallogr. 46 (1990) 194-201.
[37]PLATON: A. L. Spek, J. Appl. Crystallogr. 36 (2003) 7-13.
[38]ORTEP3 for Windows: L. J. Farrugia, J. Appl. Crystallogr. 45 (2012) 849-854.
[39]S. J. Coles, P. A. Gale, Chem. Sci. 3 (2012) 683-689.
Acknowledgements
The authors wish to thank EPSRC for the use of the National Crystallography Service at the
University of Southampton for data collection and the National mass spectrometry service at
Swansea University.
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Table 1 - Infrared spectra of crystallographically confirmed structures of the lanthanide bromide complexes.
Table 2 - Crystal data, data collection and refinement parameters.
Table 3 - Selected bond lengths (Å), bond angles (º) and non-bonded distances in Type I complexes.
Table 4 - Selected bond lengths (Å), bond angles (º) and non-bonded distances in Type II complexes.
Table 5 Shape Measures S, for the Type I and Type II complexes
Table 6 - 31P NMR data in CDCl3 at ambient temperature (unless otherwise stated).
Figure 1 - The infrared spectra of [Lu(Cy3PO)2(H2O)5]Br3 (lower) and [Lu (Cy3PO)2(H2O)5](Cy3PO)2Br3 (upper). The differences in P=O are indicated.
Figure 2 - The structure of Nd(Cy3PO)3Br3 showing the atom labelling scheme Thermal ellipsoids are drawn at the 30% probability level. H atoms have been omitted for clarity.
Figure 3 - The correlation between Ln – Br and Ln - O distances in the Type I complexes and the 6 coordinate ionic radius [18].
Figure 4 - The structure of [Er(Cy3PO)2(H2O)5](Cy3PO)2Br3 showing the atom labelling scheme Thermal ellipsoids are drawn at the 30% probability level. Cyclohexyl H atoms have been omitted for clarity.
Figure 5 - The structure and H-bonding network of [Lu(Cy3PO)2(H2O)5](EtOH)2Br3 showing the atom labelling scheme. Thermal ellipsoids are drawn at the 30% probability level. Cyclohexyl groups and ethyl H atoms have been omitted for clarity. [Symmetry codes: i = 1½-x, ½-y, 1-z; ii = 2-x, y, 1½-z]
Figure 6 - The Two Nucleus Lanthanide Induced Shift Plot for the Type II Complexes
Figure S1 - Single Nucleus Lanthanide Induced Shift Plots for Type I and Type II complexes.
19
Table 1 - Infrared spectra of crystallographically confirmed structures of the lanthanide bromide complexes.
Type I Type IIa Type IIb L
OH 3250(w) 3122(m) 3170-3180(m)
CH 2924(m), 2850(m) 2927(m), 2850(m) 2927(m), 2852(m) 2923(s),2850 (s)
(Δ/σ)max 0.003 0.003 0.004 0.001 0.002Largest diff. Peak and hole (eÅ-3) 0.669 and -0.510 0.530 and -0.747 0.474 and -0.891 1.003 and -1.715 1.068 and -1.086
Table 5 - Shape Measures S, for the Type I and Type II complexes
a. Octahedron, b. Trigonal Prism, c. Pentagonal Bipyramid, d. Capped Trigonal Prism
25
LnBr3(Cy3PO)3 [Ln(H2O)5(Cy3PO)2]+
Ln S(Oh)a S(TP)b Ln S(PBP)c S(CTP)d
La 2.262 12.512 Dy 0.307 4.899
Pr 1.419 15.922 Er 0.119 5.856
Nd 1.375 15.942 Yb 0.191 5.880
Gd 1.364 15.888 Lu 0.136 5.956
Ho 1.451 15.738
Table 6 - 31P NMR data in CDCl3 at ambient temperature (unless otherwise stated)
Type I Type IIP1
c P2d
La 61.0b 62.8,a
62.461.0
61.5b 52.4b
Pr 212.8 359.9,b 141.0
Nd 187.4, 167.6
153.3
Sm 56.5 65.0,a
58.6Eu -74.4, -
106.559.2
Tb 247.1,17.2 48.0Dy -97.8 52.7Ho 522.5, -
107.7518.4 0.5
Er -96.5 69.4Yb -7.8 70.9Lu 63.5
63.657.358.5
a -90°C in CD2Cl2 ; b at -50°C ;c Ln-OP ; d Ln-OH…OP
26
Figure 1 - The infrared spectra of [Lu(Cy3PO)2(H2O)5]Br3 (lower) and [Lu (Cy3PO)2(H2O)5](Cy3PO)2Br3 (upper). The differences in P=O are indicated.
27
Figure 2 - The structure of Nd(Cy3PO)3Br3 showing the atom labelling scheme Thermal ellipsoids are drawn at the 30% probability level. H atoms have been omitted for clarity.
28
Figure 3 The correlation between Ln – Br and Ln - O distances in the Type I complexes and the 6 coordinate ionic radius [18].
29
Figure 4 - The structure of [Er(Cy3PO)2(H2O)5](Cy3PO)2Br3 showing the atom labelling scheme Thermal ellipsoids are drawn at the 30% probability level. Cyclohexyl H atoms have been omitted for clarity.
30
Figure 5 - The structure and H-bonding network of [Lu(Cy3PO)2(H2O)5](EtOH)2Br3 showing the atom labelling scheme. Thermal ellipsoids are drawn at the 30% probability level. Cyclohexyl groups and ethyl H atoms have been omitted for clarity. [Symmetry codes: i = 1½-x, ½-y, 1-z; ii = 2-x, y, 1½-z]
31
Figure 6 - The Two Nucleus Lanthanide Induced Shift Plot for the Type II Complexes.
32
Figure S1 - Single Nucleus Lanthanide Induced Shift Plots for Type I and Type II complexes.
-50
0
50
100
150
200
-1.5 -1 -0.5 0 0.5 1
Type I
Pr
Sm
Tb HoNd
i/Ci
<Sz>i/Ci
-40
-35
-30
-25
-20
-15
-10
-5
0
5
-3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1
Type II P(a)
Eu
ErYb
Dy
Tb
Ho
i/Ci
<Sz>i/Ci
-1000
-500
0
500
1000
1500
2000
2500
-6 -4 -2 0 2 4 6 8 10 12
Type I
Pr Nd Tb
Sm
Ci/<Sz>i
Ho
i/<Sz>i
-30
-20
-10
0
10
20
30
40
-10 -8 -6 -4 -2 0 2 4 6
Type II P(a)
Yb
Er Eu
Ho
Tb
Dy
i/<Sz>i
Ci/<Sz>i
-30
-20
-10
0
10
20
30
-10 -8 -6 -4 -2 0 2 4 6
Type II P(b)
Yb
ErEu
Ho
Dy
Tb
i/<Sz>i
Ci/<Sz>i
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
-3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1
Type II P(b)
Er
Yb
Tb
Ho
Eu
Dy<Sz>i/Ci
i/Ci
33
Synopsis
Complexes of lanthanide bromides with tricyclohexylphosphine oxide (=L) form in two distinct structural types. Type I, LnBr3L3 (Ln = La, Pr, Nd, Gd and Ho) are octahedral and Type II, [Ln(H2O)5L2]L2Br3
(Ln = Dy, Er, Yb, Lu) , pentagonalbipyramidal with two L bonded to the lanthanide and two hydrogen bonded to the coordinated water. Over 99% of the changes in Ln-O and Ln-Br distances in Type I complexes can be accounted for by the lanthanide contraction. In the Type II complexes the hydrogen bonding of the coordinated water with phosphine oxides and bromide ions has a small influence on Ln-O distances Variable temperature solution 31P NMR measurements show a variety of dynamic processes. Analysis of the lanthanide induced shifts indicates structural uniformity in solution.