Di-n-butyltin methyl- and phenylphosphonates

Article abstract of DOI:10.1021/om010140x

The structure of [Bu₂Sn(HO₃PMe)₂]₂ (1), as determined by single-crystal X-ray diffraction, is based on a dimer containing bridging and terminal hydrogenophosphonate ligands. The tin atoms are formally five-coordinate, but exhibit also two additional remote contacts, d(Sn-O) ≈ 3.14 ?, which results in a 5+2 type coordination. This crystalline compound and the three other amorphous compounds, Bu₂Sn(O₃PMe) (2), Bu₂Sn(HO₃PPh)₂ (3), and Bu₂Sn(O₃PPh) (4), have been characterized by solid state ³¹P and ¹¹⁹Sn MAS NMR. Compound 1 exhibits a very well resolved ³¹P MAS NMR spectrum in which three different ²J-(³¹P-^119/117Sn)_iso scalar couplings can be measured. ³¹P and ¹¹⁹Sn NMR, ³¹P-¹⁹Sn HMQC spectroscopy, and various other 2D NMR techniques at variable temperatures were used to unravel the basic structural unit of compounds 2 and 4 in solution, which is proposed to be based on a trigonal bipyramid of the type R₂SnO₃ with two apical and one equatorial oxygen atom. Compound 1, in solution, displays a similar local geometry at tin and the same dimeric unit as in the crystalline state. In contrast with 2 and 4, however, compounds 1 and 3 display and extremely high degree of stereochemical fluxionality based on fast exchange of the bridging and terminal hydrogenophosphonate ligands.

Full text of DOI:10.1021/om010140x

Organometallics 2001, 20, 2593-2603
2593
Di-n -bu tyltin Meth yl- a n d P h en ylp h osp h on a tes
Fran c¸ ois Ribot* and Cl e´ ment Sanchez
Laboratoire de Chimie de la Mati e` re Condens e´ e (UMR CNRS 7574), Tour 54, 5e e´ tage,
Universit e´ Pierre et Marie Curie, 4 Place J ussieu, F-75252 Paris Cedex 05, France
Monique Biesemans, Fr e´ d e´ ric A. G. Mercier, J os e´ C. Martins, Marcel Gielen, and
Rudolph Willem
High Resolution NMR Centre (HNMR), Free University of Brussels (VUB), Pleinlaan 2,
B-1050 Brussel, Belgium
Received February 20, 2001
2 3 2 2
The structure of [Bu Sn(HO PMe) ] (1), as determined by single-crystal X-ray diffraction,
is based on a dimer containing bridging and terminal hydrogenophosphonate ligands. The
tin atoms are formally five-coordinate, but exhibit also two additional remote contacts, d(Sn-
O) ≈ 3.14 Å, which results in a “5+2” type coordination. This crystalline compound and
2 3 2 3 2 2
the three other amorphous compounds, Bu Sn(O PMe) (2), Bu Sn(HO PPh) (3), and Bu -
3
1
119
Sn(O
3
PPh) (4), have been characterized by solid state P and Sn MAS NMR. Compound
3
1
2
1
(
exhibits a very well resolved P MAS NMR spectrum in which three different J -
3
1
119/117
Sn)iso scalar couplings can be measured. 31P and
119
31
19
P-
Sn NMR, P- Sn HMQC
spectroscopy, and various other 2D NMR techniques at variable temperatures were used to
unravel the basic structural unit of compounds 2 and 4 in solution, which is proposed to be
based on a trigonal bipyramid of the type R SnO with two apical and one equatorial oxygen
2 3
atom. Compound 1, in solution, displays a similar local geometry at tin and the same dimeric
unit as in the crystalline state. In contrast with 2 and 4, however, compounds 1 and 3 display
an extremely high degree of stereochemical fluxionality based on fast exchange of the bridging
and terminal hydrogenophosphonate ligands.
In tr od u ction
organotin phosphonates was developed over the years,
despite recent reports on a rich organometallic and
inorganic phosphonate chemistry for numerous metals,
including tin(II) and tin(IV), which give rise to layered
Diorganotin carboxylates have been extensively in-
vestigated, because of their biological properties as well
1
as their applications in chemistry in general and more
6
-15
and/or microporous (open-framework) materials,
2
specifically in catalysis. They exist as two basic types
8
,16,17
18
molecular cages,
or Langmuir-Blodgett films.
of compounds depending on the molar ratio R′COO/R2-
Sn: as dimeric bis(dicarboxylatotetraorganodistannoxane)
microclusters of the type {[R′COOSnR2]2O}2 (I) for a
ratio of 1:1 and as monomeric coordination complexes
of the type (R′COO)2SnR2 (II) for a ratio of 2:1.3 Several
structural motifs have been observed in the crystalline
(5) (a) Meriem, A.; Willem, R.; Meunier-Piret, J .; Biesemans, M.;
Mahieu, B.; Gielen, M. Main Group Met. Chem. 1990, 13, 167. (b)
Gielen, M.; El Khloufi, A.; Biesemans, M.; Willem, R.; Meunier-Piret,
J . Polyhedron 1992, 11, 1861. (c) Gielen, M.; Bouhdid, A.; Tiekink, E.
R. T. Main Group Met. Chem. 1995, 18, 199. (d) Gielen, M.; Bou aˆ lam,
M.; Mahieu, B.; Tiekink, E. R. T. Appl. Organomet. Chem. 1994, 8,
,4
1
9.
(6) (a) Clearfield, A. Prog. Inorg. Chem. 1998, 47, 371. (b) Clearfield,
A. Chem. Mater. 1998, 10, 2801.
7) (a) Burwell, D. A.; Thompson, M. E. Chem. Mater. 1991, 3, 14.
b) Burwell, D. A.; Thompson, M. E. Chem. Mater. 1991, 3, 730. (c)
3
,4
state for the dimers of type I, but only a single one in
solution.4 The compounds of type II have a “4+2”
(
coordination scheme at tin, which exhibits the geometry
(
of a distorted trapezoidal bipyramid.3
,5
Thompson, M. E. Chem. Mater. 1994, 6, 1168. (d) Byrd, H.; Cleafield,
A.; Poojary, D.; Reis, K. P.; Thompson, M. E. Chem. Mater. 1996, 8,
In contrast with tin carboxylates, a much less clear
picture on the structural coordination chemistry of
2
9
239. (e) Medoukali, D.; Mutin, P. H.; Vioux, A. J . Mater. Chem. 1999,
, 2553.
(
8) Guerrero, G.; Mutin, P. H.; Vioux, A. Chem. Mater. 2000, 12,
1268.
(9) (a) Cheetham, A. K.; F e´ rey, G.; Loiseau, T. Angew. Chem., Int.
*
To whom correspondence should be adressed. E-mail: fri@
ccr.jussieu.fr. Fax: (33) 1 44 27 47 69.
1) (a) Gielen, M.; Lelieveld, P.; de Vos, D.; Willem, R. In Metal
Complexes in Cancer Chemotherapy; Keppler, B. K., Ed.; VCH:
Weinheim, 1993; p 383. (b) Gielen, M. Coord. Chem. Rev. 1996, 151,
1. (c) de Vos, D.; Willem, R.; Gielen, M.; van Wingerden, K. E.; Nooter,
K. Metal Based Drugs 1998, 5, 179. (d) Clarke, M. J .; Zhu, F.; Frasca,
D. R. Chem. Rev. 1999, 99, 2511.
2) (a) Smith, P. J ., Ed. Chemistry of Tin, 2nd ed.; Blackie Academic
Professional: London, 1998. (b) Davies, A. G. Organotin Chemistry,
VCH: Weinheim, 1997. (c) Mascaretti, O. A.; Furlan, R. L. E.
Aldrichim. Acta 1997, 30, 55. (d) Otera, J . Chem. Rev. 1993, 93, 1449.
(
Ed. 1999, 38, 3268. (b) Bonavia, G.; Haushalter, R. C.; O’Connor, C.
J .; Sangregorio, C.; Zubieta, J . J . Chem. Soc., Chem. Commun. 1998,
2187. (c) Finn, R. C.; Zubieta, J . Inorg. Chem. Commun. 2000, 3, 520.
(d) Rodgers, J . A.; Harrison, W. T. A. J . Chem. Soc., Chem. Commun.
2000, 2835.
(10) (a) Massiot, D.; Drumel, S.; J anvier, P.; Bujoli-Doeuff, M.; Bujoli,
B. Chem. Mater. 1997, 9, 6. (b) Bujoli-Doeuff, M.; Evain, M.; Fayon,
F.; Alonso, B.; Massiot, D.; Bujoli, B. Eur. J . Inorg. Chem. 2000, 2497.
(11) Corriu, R. J . P.; Leclercq, D.; Mutin, P. H.; Sarlin, L.; Vioux, A.
J . Mater. Chem. 1998, 8, 1827.
4
(
&
(
3) (a) Tiekink, E. R. T. Appl. Organomet. Chem. 1991, 5, 1. (b)
Tiekink, E. R. T. Trends Organomet. Chem. 1994, 1, 71.
4) Ribot, F.; Sanchez, C.; Meddour, A.; Gielen, M.; Tiekink, E. R.
T.; Biesemans, M.; Willem, R. J . Organomet. Chem. 1998, 552, 177.
(12) Poojary, D. M.; Zhang, B.; Bellinghausen, P.; Clearfield, A.
Inorg. Chem. 1996, 35, 4942.
(13) J aimez, E.; Bortlum, A.; Hix, G. B.; Garcia, J . R.; Rodriguez,
J .; Slade, R. C. T. J . Chem. Soc., Dalton Trans. 1996, 2285.
(
1
0.1021/om010140x CCC: $20.00 © 2001 American Chemical Society
Publication on Web 05/15/2001

2
594 Organometallics, Vol. 20, No. 12, 2001
Ribot et al.
1
9-24
Organotin derivatives that involve phosphates,
Tri- and diorganotin derivatives involving triply
bridging phosphorus oxo species are usually described
as polymeric compounds where tin atoms exhibit trigo-
phosphinates,2
0,23,25-31
or phosphonates
20,21,23,27,30-48
have
been reported in the literature. In many cases the
compounds are based on esterified species, and therefore
the connecting ability of the phosphorus atom is re-
duced; for example, a phosphonate monoester or a phos-
phate diester will mainly result in structural motifs
similar to a phosphinate. The following overview on oxy-
phosphorus organotin derivatives is based on the con-
nectivity patterns of the phosphorus-containing ligands.
Phosphorus atoms with four P-O-Sn links are found
in tris(dimethyltin) bis(orthophosphate), (Me2Sn)3(PO4)2‚
2
0,23,27
nal bipyramidal environments.
The only studiess
to the best of our knowledgeson dibutyltinphosphonates
with a basic structural unit of the type Bu2SnO3PR were
made at the end of the 1960s by Ridenour et al.2 (R )
C6H13, CH2C6H5, C8H17) and by Freireich et al. (R )
7a
2
7b
C6H5).
Triply bridging phenyl phosphates are also
found in a tetranuclear methyltin oxo cluster, {(MeSn)2-
2
1
(OH)[O2P(OPh)2]3[O3P(OPh)]}2.
Potentially doubly bridging phosphorus oxo deriva-
tives (i.e., phosphinates, phosphonate monoesters, or
phosphate diesters) generate polymeric compounds with
8
H2O, which forms infinite ribbons with distorted
1
9
octahedral geometries at tin. They are also encoun-
tered in tris(tributyltin) phosphate, (Bu3SnO)3PdO,
which undergoes autoassociation, as suggested by solu-
tion NMR experiments, resulting in terminal four- and
bridging five-coordinate tin atoms.20
2
0,22,23,26-29,34,38,39
di- and triorganotin structural units.
In triorganotin derivatives, the tin atom environments
generally correspond to trigonal bipyramids, with oxy-
gen atoms in apical positions. Diorganotin derivatives
display distorted octahedral geometries at tin, with a
C-Sn-C trans configuration. The X-ray structure of
Me3SnO2P(OH)Ph, for instance, shows infinite helicoidal
(
14) Fernandez, S.; Mesa, J . L.; Pizarro, J . L.; Lezama, L.; Arriortua,
M. I.; Olazcuaga, R.; Rojo, T. Chem. Mater. 2000, 12, 2092.
15) (a) Adair, B.; Natarajan, S.; Cheetham, A. J . Mater. Chem. 1998,
, 1477. (b) Stock, N.; Stucky, G. D.; Cheetham, A. Chem. Commun.
000, 2277. (c) Medeiros, M. E.; Alves, O. L. J . Mater. Chem. 1992, 2,
075. (c) Owens, C.; Pytlewski, L. L.; Karyannis, N. M.; Wysoczanski,
J .; Labes, M. M. J . Polym. Sci. B 1970, 8, 81.
16) (a) Walawalkar, M. G.; Horchler, S.; Dietrich, S.; Chakraborty,
D.; Roesky, H. W.; Sch a¨ fer, M.; Schmidt, H.-G.; Sheldrick, M.; Muru-
gavel, R. Organometallics 1998, 17, 2865, and references therein. (b)
Walawalkar, M. G.; Roesky, H. W.; Murugavel, R. Acc. Chem. Res.
(
4
0
8
2
1
chains. The polymeric structure can also be limited
to finite oligomers, as in the triphenyltin derivatives
3
6
24
{Ph3Sn[O2P(OMe)Me]}6 and {Ph3Sn[O2P(OPh)2]}6,
(
which form only cyclohexamers. When more complex
organic moieties are bound to tin, monomeric or dimeric
compounds, yet with purely monodentate phosphorus
oxo derivatives, can be observed as in the X-ray struc-
ture of 1-methyl-5-(O-tert-butylphosphonic acid)-1-aza-
1
999, 32, 2, 117, and references therein.
17) (a) Mehring, M. M.; Guerrero, G.; Dahan, F.; Mutin, P. H.;
Vioux, A. Inorg. Chem. 2000, 39, 3325. (b) Guerrero, G.; Mehring, M.;
Mutin, P. H.; Dahan, F.; Vioux, A. J . Chem. Soc., Dalton Trans. 1999,
(
1
,5
45
5-stannabicyclo[3.3.0 ]octane, {5-tert-butyl-7-diethoxy-
1
537. (c) Errington, R. J .; Ridland, J .; Willett, K. J .; Clegg, W.; Coxall,
phosphonyl-3-ethoxy-3-oxo-1,1-diphenyl-2,3,1-benzoxa-
R. A.; Health, S. L. J . Organomet. Chem. 1998, 550, 473.
4
1
(
(
18) Petrushka, M. A.; Talham, D. R. Langmuir 2000, 16, 5123.
19) Ashmore, J . P.; Chivers, T.; Kerr, K. A.; Van Roode, J . H. G.
phosphastannole, or di-n-butyltin pyridine-2-phospho-
37
nate-6-carboxylate. In the latter case, the tin atom is
Inorg. Chem. 1977, 16, 191.
20) Blunden, S. J .; Hill, R.; Gillies, D. G. J . Organomet. Chem. 1984,
70, 39.
21) Swamy, K. C. K.; Schmid, C. G.; Day, R. O.; Holmes, R. R. J .
Am. Chem. Soc. 1990, 112, 223.
22) (a) Kowalski, J .; Chojnowski, J . J . Organomet. Chem. 1980, 193,
seven-coordinate via the addition of a water molecule,
corresponding to a pentagonal bipyramid with two
apical carbon atoms. Several monoorganotin oxo clusters
based on doubly bridging phosphorus oxo derivatives
and hexacoordinated tin atoms have also been reported
(
2
(
(
1
91. (b) Molloy, K. C.; Nasser, F. A. K.; Zuckerman, J . J . Inorg. Chem.
982, 21, 1711. (c) Otera, J .; Yano, T.; Kunimoto, E.; Nakata, T.
1
21,25
by Holmes and co-workers.
Organometallics 1984, 3, 426.
23) Chivers, T.; van Roode, J . H. G., Ruddick, J . N. R.; Sams, J . R.
Can. J . Chem. 1973, 51, 3702.
24) Molloy, K. C.; Nasser, F. A. K.; Barnes, D.; Van der Helm, D.;
Zuckerman, J . J . Inorg. Chem. 1982, 21, 960.
25) (a) Holmes, R. R. Acc. Chem. Res. 1989, 22, 190, and references
(
A variety of organotin compounds with nonbridging
phosphorus oxo derivatives, mainly phosphonate di-
esters and phosphinate monoesters, have also been
(
3
0-33,35,42-44,46-48
(
reported.
Such compounds mostly cor-
therein. (b) Day, R. O.; Holmes, J . M.; Chandrasekhar, V.; Holmes, R.
respond to adducts on organotin halides, RnSnX4-n (n
R. J . Am. Chem. Soc. 1987, 109, 9, 940.
(
26) Sidib e´ , M.; Lahlou, M.; Diop, L.; Mahieu, B. Main. Group Met.
Chem. 1998, 21, 605.
27) (a) Ridenour, R. E.; Flagg, E. E. J . Organomet. Chem. 1969,
1
1
(37) Gielen, M.; Dalil, H.; Ghys, L.; Boduszek, B.; Tiekink, E. R. T.;
Martins, J . C.; Biesemans, M.; Willem, R. Organometallics 1998, 17,
4259.
(38) (a) Pandey, J . N.; Srivastava, G. J . Organomet. Chem. 1988,
354, 301. (b) Nietzschmann, E.; Kellner, K. Phosphorus, Sulfur Silicon
Relat. Elem. 1991, 55, 73.
(
6, 393. (b) Freireich, S.; Gertner, D.; Zilkha, A. J . Organomet. Chem.
970, 25, 111.
(
(
28) Shihada, A.-F. Z. Naturforsch. B Chem. Sci. 1994, 49, 1319.
29) Shihada, A.-F.; Yousif, H. R. Z. Naturforsch. B Chem. Sci. 1991,
4
6, 1568.
30) Grigoriev, E. V.; Yashina, N. S.; Prischenko, A. A.; Livantsov,
(39) Cunningham, D.; Kelly, L. A.; Molloy, K. C.; Zuckerman, J . J .
Inorg. Chem. 1982, 21, 1416.
(
M. V.; Petrosyan, V. S.; Pellerito, L.; Schafer, M. J . Appl. Organomet.
Chem. 1993, 7, 353.
(40) Molloy, K. C.; Hossain, M. B.; Van der Helm, D.; Cunningham,
D.; Zuckerman, J . J . Inorg. Chem. 1981, 20, 2402.
(41) Mehring, M.; L o¨ w, C.; Sch u¨ rmann, M.; J urkschat, K. Eur. J .
Inorg. Chem. 1999, 887.
(42) Lorberth, J .; Shin, S.-H.; Otto, M.; Wocadlo, S.; Massa, W. J .
Organomet. Chem. 1991, 407, 313.
(
31) Richter, F.; Dargatz, M.; Hartung, H.; Schollmeyer, D.; Weich-
mann, H. J . Organomet. Chem. 1996, 514, 233.
32) Grigoriev, E. V.; Yashina, N. S.; Prischenko, A. A.; Livantsov,
(
M. V.; Petrosyan, V. S.; Massa, W.; Karms, K.; Wocadlo, S.; Pellerito,
L. Appl. Organomet. Chem. 1995, 9, 11.
(43) Freitag, S.; Herbst-Irmer, R.; Richter, F. U.; Weichmann, H.
Acta Crystallogr. 1994, C50, 1558.
(44) Lorberth, J .; Wocadlo, S.; Massa, W.; Grigoriev, E. V.; Yashina,
N. S.; Petrosyan, V. S.; Finocchiaro, P. J . Organomet. Chem. 1996,
510, 287.
(45) Dakternieks, D.; J urkschat, K.; Tiekink, E. R. T. Z. Kristallogr.
1996, 211, 755.
(46) Hartung, H.; Krug, A.; Richter, F.; Weichmann, H. Z. Anorg.
Allg. Chem. 1993, 619, 859.
(
33) Mehring, M.; Sch u¨ rmann, M.; J urkschat, K. Organometallics
998, 17, 1227.
34) (a) Kellner, K.; Rodewald, L.; Schenzel, K. Phosphorus, Sulfur
1
(
Silicon Relat. Elem. 1991, 55, 65. (b) Chaturvedi, A.; Sharma, R. K.;
Nagar, P. N.; Rai, A. K. Phosphorus, Sulfur Silicon Relat. Elem. 1996,
1
12, 179.
35) Grigoriev, E. V.; Yashina, N. S.; Petrosyan, V. S.; Pellerito, L.;
(
Gianguzza, A.; Pellerito, A.; Avtomonov, E. V.; Lorberth, J .; Prischenko,
A. A.; Livantsov, M. V. J . Organomet. Chem. 1999, 577, 113.
(47) Kolb, U.; Dr a¨ ger, M.; Fischer E.; J urkschat, K. J . Organomet.
Chem. 1992, 423, 339.
(48) Hartung, H.; Krug, A.; Richter, F.; Weichmann, H.; Zeigan, D.
Main Group Metal Chem. 1994, 17, 603.
(
36) Masters, J . G.; Nasser, F. A. K.; Hossain, M. B.; Hagen, A. P.;
Van der Helm, D.; Zuckerman, J . J . J . Organomet. Chem. 1990, 385,
9.
3

Di-n-butyltin Methyl- and Phenylphosphonates
Organometallics, Vol. 20, No. 12, 2001 2595
)
1, 2, 3 and X ) Cl or Br), where the coordination of
In a first step, tetra-n-butyldi-n-propoxydistannoxane,
(n-Bu2PrOSn)2O, is prepared from di-n-butyltin oxide
and n-propanol in refluxing benzene, under elimination
of water. This distannoxane reacts in situ after cooling
to room temperature with the phosphonic acid, either
in 1:2 or in 1:1 molar ratio, leading to respectively
compounds 1 and 2 for the reaction with methylphos-
phonic acid (H2O3PMe) and 3 and 4 for the reaction with
phenylphosphonic acid (H2O3PPh).
tin is expanded to 5 or 6 by the oxygen atom of the Pd
O groups. The use of bifunctional nonbridging phospho-
rus oxo derivatives (e.g., (EtO)2P(O)CH(Me)P(O)(OR)2)
3
2
3
2,44
42,43,47
can lead to structures based on chains,
dimers,
or even monomers.3
1,33,35,46
The formation of phosphoryl
adducts have also been reported for tetraorganotin
derivatives bearing a rigid O,C,O-pincer group of the
3
3
type (2,6-bis(diethoxyphosphonyl)-4-tert-butyl)phenyl.
For such cases, the Sn-O contacts generated are weak
2.8-3.0 Å), and the tin coordination is better described
The compounds synthesized were identified by el-
emental analysis and NMR data to have the empirical
formulas Bu2Sn(HO3PMe)2 for compound 1, Bu2Sn(O3-
PMe) for compound 2, Bu2Sn(HO3PPh)2 for compound
3, and Bu2Sn(O3PPh) for compound 4. Indeed, the FT-
IR spectra of compounds 1 and 3 both exhibit two broad
(
as “4+2”. On the contrary, the corresponding dichlorotin
derivative leads to stronger Sn-O contacts (2.2-2.4 Å)
and a six-coordination at tin.33
The few data available on diorganotin nonesterified
phosphonates,2 as well as the diversity in the structures
and coordination chemistry of organotin phosphonates
in crystalline and amorphous states sketched above and
the potentials of such derivatives in material sciences
illustrated by other metals, prompted us to synthesize
and investigate novel di-n-butyltin phosphonates, from
which a novel structural class emerged. The strategy
adopted was based on the well-known chemistry of
diorganotincarboxylates,2 in which the molar ratio 1:1
or 1:2 of Bu2SnO to R′COOH enables one to modulate
the structure of the desired compounds. It was expected
that varying the molar ratio Bu2SnO/methyl- or phe-
nylphosphonic acid (1:1 or 1:2 molar ratios) would
likewise give rise to a similar structural diversity and
contribute to the development of novel diorganotin
coordination compounds. However, phosphonates are
potentially tridentate dianionic ligands and differences
with carboxylates (bidentate and monoanionic) can be
expected.
7
-1
vibrations centered at 2370 and around 2820 cm . The
frequency of the later is ill-defined, as it partially
overlaps with the C-H stretching bands. These two
broad vibrations are in the ranges for O-H stretching
involved in a strong or moderate hydrogen bond, re-
5
2
spectively. On the contrary, the FT-IR spectra of
compounds 2 and 4 do not show such vibrations.
The compounds 1 and 3 are generated according to
-5
4 H O P-R + [Bu Sn(OPr)] O f
2
3
2
2
2
Bu Sn(HO P-R) + 2 PrOH + H O
2 3 2 2
whereas compounds 2 and 4 are obtained from the
reaction
2
H O P-R + [Bu Sn(OPr)] O f
2 3 2 2
2
Bu Sn(O P-R) + 2 PrOH + H O
2 3 2
The 1:2 compounds 1 and 3 show little to no solubility
The present work offered us the opportunity to
3
1
in most usual organic solvents, except in methanol,
where it is anyhow limited (e.g., 1 mg/0.5 mL for 1). By
contrast, the 1:1 compounds 2 and 4 are better soluble
in most organic solvents, like chloroform, dichlo-
romethane, benzene, and methanol, up to 60 mg for 2
and 100 mg for 4 in 0.5 mL of dichloromethane or
benzene/methanol (1:1 vol.). Tonometry performed on
implement and assess the use of P-detected 2D HMQC
4
9
31
119
NMR spectroscopy applied to the P- Sn pair, to
2
31
119/117
identify complex J ( P-O-
Sn) coupling patterns
and getting, in this way, insight into possible structures.
3
1
m
Several P- Y correlation experiments have been
1
3
performed with nonmetals, predominantly C and
1
5
50 31
31
m
N.
P-detected HMQC P- Y pulse sequences have
4
in chloroform, in the concentration domain ranging
also been used to investigate the structure of silver,
platinum, and mercury complexes, as well as of orga-
from 2 to 65 mg of 4 per gram of solvent, reveals a mean
molar mass of ca. 5000 ( 100 g/mol, which indicates
aggregation in solution. The number of Bu Sn(O PPh)
2 3
units per oligomer averages 12.9. The linearity of the
tonometry measurements on the explored concentration
range suggests the absence of equilibrium between
several oligomers of different molar masses. This value
of 5000 g/mol is lower than those reported between
10 000 and 7000 g/mol by Freireich et al. on several
poly(dibutyltin phenylphosphonate)s which consisted of
5
0
notungsten, -iron, and -rhodium compounds. However,
except for the case of 31P- Li, correlations between
6
31
P
and main group metal nuclei have not been reported.
Resu lts a n d Discu ssion
Syn th esis. The di-n-butyltin derivatives of methyl-
and phenylphosphonic acid were synthesized by a
method described for carboxylic acids by Davies et al.
5
1
polymers of the same basic chemical unit, Bu2Sn(O3-
(
49) (a) Bax, A.; Griffey, R. H.; Hawkins, B. L. J . Magn. Reson. 1983,
5, 301. (b) Bax, A.; Summers, M. F. J . Magn. Reson. 1986, 67, 565.
c) Bax, A.; Summers, M. F. J . Am. Chem. Soc. 1986, 108, 2093. (d)
27b
PPh), than 4.
However, Freireich’s polymeric com-
5
(
pounds were prepared according to a process differing
fairly from ours (different precursors, biphasic media,
much shorter times). Moreover, Freireich et al. observed
Kayser, F.; Biesemans, M.; Gielen, M.; Willem, R. In Advanced
Applications of NMR to Organometallic Chemistry; Gielen, M., Willem,
R., Wrackmeyer, B., Eds.; J ohn Wiley & Sons: Chichester, 1996;
Chapter 3, p 45. (e) Berger, S.; F a¨ cke, T.; Wagner, R. In Advanced
Applications of NMR to Organometallic Chemistry; Gielen, M., Willem,
R., Wrackmeyer, B., Eds.; J ohn Wiley & Sons: Chichester, 1996;
Chapter 2, p 29. (f) Kayser, F.; Biesemans, M.; Gielen, M.; Willem, R.
J . Magn. Reson. A 1993, 102, 249. (g) Martins, J . C.; Biesemans, M.;
Willem, R. Prog. NMR Spectrosc. 2000, 36, 271.
an influence of the synthesis solvent on the molar
27b
masses of their polymers.
Ridenour et al. have
reported for similar Bu2Sn(O3PR) dibutyltinphospho-
(52) (a) Novak, A. Struct. Bonding 1974, 18, 177. (b) Hibbert, F.;
Emsley, J . Adv. Phys. Org. Chem. 1990, 26, 255. (c) Bellamy, L. J .;
Owen, A. J . Spectrochim. Acta 1969, 25A, 329. (d) Mikenda, W. J . Mol.
Struct. 1986, 147, 1.
(
50) Gudat, D. Annu. Rep. NMR Spectrosc. 1999, 38, 139.
(51) Davies, A. G.; Kleinschmidt, D. C.; Palan, P. R.; Vasishtha, S.
C. J . Chem. Soc. 1971, 3972.

2
596 Organometallics, Vol. 20, No. 12, 2001
Ribot et al.
F igu r e 1. CAMERON53 drawing of {Bu
, showing 30% displacement ellipsoids.
2
3 2 2
Sn(HO PMe) } ,
1
nates (R ) C6H13, CH2C6H5, C8H17) oligomerization
degrees ranging from 5 to 37.2 Therefore, the molar
mass found for compound 4 does not appear contradic-
tory with the results of Freireich et al.,27b but mainly
indicates that our experimental conditions yield a
lighter oligomer.
7a
Crystals suitable for X-ray diffraction analysis could
be obtained for compound 1 only, the compounds 2, 3,
and 4 giving rise to amorphous materials.
F igu r e 2. CAMERON53 drawing of {Bu
, showing the long-range organization of the dimers in
2
3 2 2
Sn(HO PMe) } ,
1
Cr ysta llin e Str u ctu r e of 1. The structure of 1, as
determined by X-ray diffraction analysis, is presented
in Figures 1 and 2.53 Selected interatomic distances and
bond angles are given in Table 1. The molecular
structure of 1 corresponds to a centrosymmetric dimer
based on an eight-membered ring containing two five-
coordinate tin atoms which exhibit distorted trigonal
bipyramid environments (oxygen atoms in apical posi-
tion, angle O1-Sn1-O2 ) 172.1(1)°). One phosphonate
group (P1) forms a nonsymmetrical bridge (d(Sn1-O1)
the plane ab (large black circle, Sn; medium gray circle, P;
small dark circle, O; and small white circle, C). Hydrogen
bonds (〈d〉 ) 2.57 Å) and weak Sn-O contacts (〈d〉 ) 3.14
Å) are drawn as dotted and dashed lines, respectively.
Ta ble 1. Selected In ter a tom ic Dista n ces (Å) a n d
Bon d An gles (d eg) for {Bu
2
Sn (HO
3
Pa Me)
2
}
2
(1) w ith
Esd in P a r en th eses
Sn1-O1
Sn1-O2
Sn1-O3
Sn1-C1
Sn1-C5
2.165(4) P1-O1
2.197(4) P1-O3′
2.058(4) P1-O11
2.110(5) P1-C11
1.498(4) P2-O2
1.501(4)
1.511(4)
1.559(4)
1.779(8)
1.512(4) P2-O21
1.564(5) P2-O22
1.786(7) P2-C21
)
2.165(4) and d(O1-P1) ) 1.498(4), or d(Sn1′-O3′) )
.058(4) and d(O3′-P1) ) 1.512(4) Å). The other one
P2) is formally terminal (d(Sn1-O2) ) 2.197(4) and
d(O2-P2) ) 1.501(4) Å). However, two oxygen atoms
O2 and O22) of this terminal phosphonate form weak
contacts (3.099(5) and 3.183(4) Å), nevertheless smaller
2
(
2.107(6) O21- - -O22* 2.553(6) O21- - -O11′′′ 2.587(6)
Sn1- - -O2′′ 3.183(4) Sn1- - -O22′′ 3.099(5)
O1-Sn1-O2
O1-Sn1-O3
O2-Sn1-O3
O1-Sn1-C1
O2-Sn1-C1
O3-Sn1-C1
O1-Sn1-C5
O2-Sn1-C5
O3-Sn1-C5
C1-Sn1-C5
Sn1-O1-P1
Sn1-O2-P2
Sn1-O3-P1′
Sn1-C1-C2
Sn1-C5-C6
172.1(1)
88.4(2)
84.2(2)
92.8(2)
91.6(2)
103.0(2)
88.2(2)
90.9(2)
104.1(2)
152.9(2)
153.1(3)
143.2(2)
142.5(2)
113.0(5)
112.1(5)
O1-P1-O3′
O1-P1-O11
O3′-P1-O11
O1-P1-C11
O3′-P1-C11
O11-P1-C11
O2-P2-O21
O2-P2-O22
O21-P2-O22
O2-P2-C21
O21-P2-C21
O22-P2-C21
114.7(2)
112.7(3)
105.7(3)
108.2(3)
107.8(3)
107.3(3)
116.1(3)
106.3(2)
109.8(2)
108.8(4)
110.0(4)
105.2(4)
(
5
4
than the sum of the van der Waals radii (3.70 Å), with
a tin atom belonging to a neighboring dimer. These
contacts result in the formation of chains of dimers
along the b axis, such that the coordination of tin is
better described as “5+2” (Figure 2). The deviation from
the standard trigonal bipyramidal environment is also
confirmed by the value of the C1-Sn1-C5 angle, 152.9-
(2)°, which is much larger than 120°. A network of
hydrogen bonds, associated with an average O-O
distance of 2.57 Å, assembles these chains into planes
parallel to the a and b axes (Figure 2). According to the
correlation between ν(O-H) and d(OH-O) given by
Novak,5 this average distance would agree with an
a
′
refers to symmetry -x, 1-y, 1-z; ′′ refers to symmetry -x,
*
-y, 1-z; ′′′ refers to symmetry 1+x, y, z; refers to symmetry 1-x,
y, 1-z.
-
2a
of 1 exhibits broad vibrations in both regions, and a
more conclusive assignment appears difficult. The acidic
hydrogen atoms of the hydrogenophosphonates could
not be located on the final difference Fourier map. Yet,
according to the hydrogen bonds (Figure 2) and to the
lengths of the P-O bonds (Table 1), they are likely
located on O11 (for P1) and O22 (for P2).
-
1
O-H stretching of 2370 cm , in the strong hydrogen
5
2b
bonds region. Yet, the works of Hibbert et al.
and
5
2c
Bellamy et al.
would correlate such an OH-O dis-
-
1
tance with an O-H stretching around 2800 cm , in the
moderate hydrogen bonds region. The FT-IR spectrum
(53) (a) Watkin, D. J .; Prout, C. K.; Pearce, L. J . CAMERON;
1
19
Sn a n d 31P MAS NMR Stu d ies of
Solid Sta te
Chemical Crystallography Laboratory, University of Oxford: Oxford,
U.K., 1996.
3
1
1
1. The P{ H} MAS NMR spectrum of 1 is presented

Di-n-butyltin Methyl- and Phenylphosphonates
Organometallics, Vol. 20, No. 12, 2001 2597
Ta ble 2. 31P MAS NMR Da ta
δiso
ppm)
ú
σ11
(ppm)
σ22
(ppm)
σ33
(ppm)
intensity
(%)
2J iso(31P-119/117Sn)
(
(ppm)
η
(Hz)
{
22
-61
Bu2Sn(HO3PMe)2}2 (1)
1
1
X
Y
21.3
16.9
-50
50
0.75
0.80
-15
-22
-71
32
50
50
160
130-215
Bu2Sn(O3PMe) (2)
2
X
13.4
-37
0.65
17
-7
-50
100
Bu2Sn(HO3PPh)2 (3)
3
3
3
X
Y
Y′
13.3
4.5
3.8
58
-62
-66
0.80
0.85
0.85
-65
-19
44
-66
-70
49
28
22
52
57
0
1
Bu2Sn(O3PPh) (4)a
4
4
4
X
Y
Z
3.3
28
65
7
-0.2
-4.6
a
The phosphorus resonances were so broad and strongly overlapping that no attempt to extract the shielding parameters was made.
frequency when the phosphonate connectivity increases
1
0a,55
from a “111” to a “122” type.
assignment turns opposite, as the bridging phosphonate
P1), which exhibits a higher connectivity (“011”) than
At first glance, our
(
the terminal phosphonate (P2, “001”), corresponds to the
signal at low frequency. However, if the weak Sn-O
contacts (∼3.15 Å) are included in the connectivity
analysis, the so-called terminal phosphonate (P2) turns
to a “012” connectivity, which is higher than the “011”
connectivity of the bridging phosphonate (P1), and our
assignment follows the rule found for the zinc phospho-
nates. This effect of the connectivity on the isotropic
chemical shift should anyhow be considered with some
care, as it was established for too small a number of
compounds, all based on fully deprotonated phospho-
nates, which is not the case here. Moreover, the same
connectivity can lead to fairly different chemical shifts,
F igu r e 3. Experimental and simulated 31P MAS NMR
spectrum of {Bu Sn(HO PMe) } , 1, under high-power
2 3 2 2
3
1
as observed for some titanium derivatives (δiso( P) ≈
proton decoupling, νMAS ) 1700 Hz (the isotropic resonances
i
6
.5 ppm for the cage compounds [Ti4(µ3-O)(OPr )5(µ-
are pointed out with arrows). The inset shows an expansion
i
31
2
31
119/117
OPr )3(O3PPh)3]‚DMSO and δiso( P) ) -4 ppm for
lamelar Ti(O3PPh)2, the phosphonate ligands in these
of the isotropic resonances with the J ( P-
Sn) satel-
lites pointed out.
8
,13,17a
compounds being all “111”).
in Figure 3. It reveals the existence of two unequivalent
sites (1X and 1Y), the NMR characteristics and relative
populations of which have been extracted by simulation
The asymmetries (Table 2) are close to unity for both
types of phosphorus in compound 1, indicating that local
geometries are very far away from 3-fold or higher
symmetry, as expected for terminal or bridging hydro-
genophosphonates. Such high asymmetries have already
been reported for various phosphonic acids and
(Table 2). The two sites are equally populated, in
agreement with the X-ray structure. All the resonances
(
(
isotropic or spinning sidebands) also exhibit satellites
two pairs for 1Y and one pair for 1X) which can be
zinc phosphonates which exhibit “112” or “122” con-
2
31
119/117
assigned to unresolved J ( P-
plings. The intensity of each pair of satellites is 16 (
% of the corresponding site, indicating that each
Sn) scalar cou-
10a,55-57
nectivities.
The magnitude of the shielding
anisotropies (Table 2) are comparable to values reported
1
56,57
for phosphonic acids,
zirconium carboxyalkylphos-
3
1
coupling to the P nucleus involves a single tin atom.
This feature is in perfect agreement with the molecular
structure of 1 as determined from X-ray analysis and
enables one to assign unambiguously the low-frequency
site (1Y) to the unsymmetrical bridging phosphonate
58
phonates, zinc phosphonates, and galium phospho-
nates. The change of sign of the shielding anisotropies,
10
as observed between sites 1Y (P1) and 1X (P2), has
already been observed and arises from the large values
(
54) Bondi, A. J . Phys. Chem. 1964, 68, 441.
(P1) and the high-frequency site (1X) to the terminal
(55) The connectivity of a phosphonate is labeled from the number
phosphonate (P2). Indeed, P1 is linked to Sn1 and its
symmetric Sn1′ through two paths (P1-O1-Sn1 and
P1-O3′-Sn1′) of different length, while P2 is linked to
Sn1 through a unique path (P2-O2-Sn1). One can note
that the main difference between the two phosphorus
atom environments is only observed in the O-P-X
angles (X ) O or C) and not in the P-O and P-C
distances (∆dmax ) 0.004 Å e esd).
of metal atoms bound to each oxygen; for example, a connectivity noted
“111” corresponds to a phosphonate where each oxygen is bound to a
single metal, while a connectivity noted “122” corresponds to a
phosphonate where one oxygen is bound to a single metal and the two
10a
other ones are bound to two metals each.
(56) (a) Harris, R. K.; Merwin, L. H.; H a¨ gele, G. J . Chem. Soc.,
Faraday Trans. 1 1989, 85, 1409. (b) Harris, R. K.; Merwin, L. H.;
H a¨ gele, G. Magn. Res. Chem. 1989, 27, 470.
(57) (a) Klose, G.; Trahms, L.; M o¨ ps, A. Chem. Phys. Lett. 1985, 122,
5
45. (b) Klose, G.; M o¨ ps, A.; Grossmann, G.; Trahms, L. Chem. Phys.
Lett. 1990, 175, 472.
58) Burwell, D. A.; Valentine, K. G.; Thompson, M. E. J . Magn.
Reson. 1992, 97, 498.
3
1
A
P NMR study on a series of lamelar zinc phos-
(
3
1
phonates revealed that the δiso( P) moves to high

2
(
598 Organometallics, Vol. 20, No. 12, 2001
Ribot et al.
Ta ble 3. 119Sn MAS NMR Da ta
terminal phosphonates, yet opposite the case of 1 if the
high-frequency site (3X) is considered as terminal.
The 31P{1H} MAS NMR spectrum of compound 2
shows only a single broad resonance (450 Hz). The
isotropic P chemical shift, at lower frequency than the
bridging phosphonate of 1, suggests the existence of
phosphonates in which the three oxygens atoms are
bound to tin atoms (i.e., connectivity “111” or higher).
The presence of such triply bridging phosphonates was
δ
iso
ú
σ
11
σ
22
σ
33
intensity
(%)
ppm) (ppm)
η
(ppm) (ppm) (ppm)
Bu Sn(HO PMe) (1)
337.0 825 0.35 -220 69
Bu
coordination
{
2
3
2 2
}
1160
-
100
5+2
31
2
Sn(O
170
230
3
PMe) (2)
880
-
-
276.5 600 0.65 -220
285.0 560 0.80 -220
45
55
5
5
850
Bu
2
Sn(HO
3 2
PPh) (3)
-
-
277.5 770 0.45 -280
60
1050
100
100
5
5
previously proposed to explain the polymeric nature of
Bu
2
Sn(O
3
PPh) (4)
27a
[
Bu2Sn(O3PR)]n (R ) C6H13, CH2C6H5, C8H17).
The
280.0 630 0.70 -255
185
910
smaller anisotropy and asymmetry, as compared to 1,
also suggest a different type of phosphonate.
of the asymmetries and from the sorting protocol of the
σii values established by Haeberlen.56,59 Two alternative
The 31P{ H} NMR spectrum of compound 4 is much
more complex. Three main broad (300 to 500 Hz) and
overlapping resonances, roughly in a 4:9:1 ratio, can be
deconvoluted. Because of the spectrum complexity, no
1
parameters, associated with a different sorting protocol,
can be used: the span and the skew.60 For compound 1,
the spans of both sites turn to be identical, at 93 ppm,
3
1
P shielding tensor parameters could be extracted
and the skews are 0.16 and -0.20 for 1Y (P1) and 1X
reliably. The isotropic chemical shifts suggest that two
or three oxygen atoms of the various phosphonates are
bound to tin atoms. The nonequivalence and the large
width of the resonances are in line with the amorphous
nature of compound 4.
(P2), respectively. The latter parameter has been found
to increase with the phosphonate connectivity in a series
of zinc and gallium phosphonates.10 Yet, according to
the nonunivocal connectivity scheme for the phospho-
nates of compound 1 (“001” vs “012”, vide supra), the
proposed correlation seems difficult to verify here.
The 119Sn MAS NMR spectrum of 1 shows only one
The 119Sn MAS NMR spectra of compounds 3 and 4
exhibit a single isotropic resonance, the line-width of
which is slightly larger than for 1. Compound 2 exhibits
site, in agreement with the X-ray structure (Table 3).
The line-width of the resonances (∼1000 Hz) prevents
the observation of the multiplicity pattern expected from
1
19
two overlapping
Sn isotropic resonances, in a 1:1
ratio, with widths comparable to 1. These large widths
prevent, even more than for 1, the observation of any
2
119
31
the J ( Sn- P) couplings. The isotropic resonance
-337 ppm) can be considered as characteristic for a
2
119
31
J ( Sn- P) scalar coupling splittings. Importantly,
(
1
19
the
Sn isotropic chemical shifts are very similar for
dibutyltin in a “5+2” coordination site. Indeed, the two
Sn-O remote contacts (∼3.15 Å, vide supra) have to be
the three amorphous solids 2, 3, and 4 (ca. -280 ( 5
ppm) but about 60 ppm at higher frequency than for 1.
This last point suggests that the tin environments in
compounds 2, 3, and 4 are only five-coordinate, the 60
ppm low-frequency shift for 1 being related to the
presence of the two additional weak Sn-O contacts
taken into account in the shieding of the 119Sn nucleus,
as recently evidenced in {(BuSn)12O14(OH)6}(4-CH3C6H4-
SO3)2‚C4H8O2, where a single tin-oxygen remote con-
tact of about 3.3 Å is able to induce a shielding of about
6
1
2
5 ppm.
6
1
Solid Sta te 119Sn a n d
31
found in its structure. The smaller anisotropies and
the larger asymmetries also suggest a different coordi-
nation, likely smaller at tin than in compound 1.
P MAS NMR Stu d ies of
3
1
1
2
, 3, a n d 4. The data of the solid state P{ H} and
1
19
Sn MAS NMR spectra extracted by simulation for the
Solu tion Sta te NMR Da ta of Com p ou n d s 1 a n d
three other compounds, which are all amorphous, are
reported in Tables 2 and 3.
1
13
3
. The H and C NMR spectra of compound 1 in CD3-
The 3 P{ H} NMR spectrum of compound 3, which
1
1
OD display the signals characteristic for a methyl group
bound to phosphorus (doublet) and n-butyl groups bound
to tin, with their relative integrated areas as expected
from the molar ratio of the reaction mixture (2 equiv of
CH3PO(OH)2 and 1 equiv of Bu2SnO). In contrast with
exhibits a Sn:P ratio of 1:2 as 1, shows three resonances,
approximately in a 2:1:1 ratio. The 31P resonances are
broader than those of 1 (100 Hz vs 40 Hz), and no
2
31
119
J ( P- Sn) coupling satellite could be observed. The
two groups of resonances (3X, on one hand, and 3Y and
Y′, on the other hand) suggest, by comparison with the
3
1
the solid state spectrum, the P NMR solution spectrum
of 1 displays only a single broad resonance at 21.6 ppm,
3
2
31
119/117
without any J ( P-
Sn) coupling satellites. This
results obtained for 1 and considering the usual low-
chemical shift is similar to the one found in the solid
state for a terminal phosphonate (P2). The coupling
frequency shift (ca. 10 ppm) upon methyl to phenyl
1
7a
substitution in phosphonates, the presence of the two
types of phosphonate groups, i.e., bridging (3Y and 3Y′)
and terminal (3X). This proposal is supported by the
1
19
splitting is also absent in the
Sn NMR solution
spectrum, which displays a rather sharp resonance at
-278 ppm in a 1:1 CD3OD/C6D6 solution, ca. 60 ppm to
higher frequency with reference to the solid state 1 Sn
isotropic chemical shift. In pure CD3OD, despite the
lower solubility, a slight concentration effect on the
3
1
P shielding tensor anisotropies and asymmetries
Table 2), which are very similar to those of compound
. Here also a sign change occurs between the anisotro-
pies associated with the presumably bridging and
19
(
1
1
19
Sn chemical shifts could be observed, ca. 8 ppm to
high frequency upon 5-fold dilution. These data, com-
(
59) Haeberlen, U. Adv. Magn. Reson. Suppl. 1 1976.
2
31
119/117
(60) (a) Mason, J . Solid-State Nucl. Magn. Reson. 1993, 2, 285. (b)
bined with the absence of J ( P-
Sn) coupling
J ameson, C. J . Solid State NMR 1998, 11, 265.
61) Eychenne-Baron, C.; Ribot, F.; Steunou, N.; Sanchez, C.; Fayon,
F.; Biesemans, M.; Martins J . C.; Willem, R. Organometallics 2000,
9, 1940.
satellites, indicate that the structure observed in the
solid state by X-ray crystallography and supported by
the solid state NMR data no longer exists as such in
(
1

Di-n-butyltin Methyl- and Phenylphosphonates
Organometallics, Vol. 20, No. 12, 2001 2599
solution and that an intermolecular exchange of the
phosphonate moieties fast on the 119Sn and P time
scales must take place. The latter kind of exchange was
already reported earlier for SnCl4, RSnCl3, R2SnCl2, and
R3SnCl adducts of the zwitterionic ethyl phosphonate,
31
-
+
35
EtOPO2 CH2N Me2Et.
Decreasing the temperature down to 213 K fails to
2
31
reveal any decoalescence of the resonance toward J ( P-
1
19/117
119
31
Sn) multiplets and satellites in the
Sn and
P
spectra, respectively, even in the very diluted solution
necessarily used because of the very limited solubility
of 1 (and 3). Temperature decrease down to 163 K leads
to decoalescence of the single 31P resonance into a major,
relatively narrow resonance at 29.5 ppm and several
smaller ones between 19 and 23 ppm, however without
2
31
119/117
any J ( P-
Sn) multiplet decoalescence, showing
that the intermolecular exchange of phosphonates is
extremely fast, even at the lowest temperatures acces-
sible. The 1 Sn resonance shifts, in CD3OD, from -289
ppm at room temperature to ca. -348 ppm, at 243 K,
and simultaneously undergoes a dramatic broadening
19
3
1
1
F igu r e 4. P{ H} spectrum of compound 4 in CD
13 and 273 K.
2 2
Cl at
2
(from ca. 50 to 400 Hz), leading to a loss of signal-to-
noise ratio, followed at lower temperatures by an
apparent, ill-defined, decoalescence. Similar observa-
tions were made in the 1 Sn and P NMR spectra of
19
31
1
the other Bu2Sn(HO3PR)2 compound 3 (R ) Ph), the H
and 13C spectra being as expected.
Solu tion Sta te NMR Da ta of Com p ou n d s 2 a n d
1
4
. The H NMR spectrum of compound 2 displays a
pattern depending on the nature of the solvent. In a
CDCl3/CD3OD mixture, the resonances are broad, en-
abling one only to identify the butyl groups and to
confirm the ratio of butyl-to-methyl protons expected
from the 1:1 Bu2SnO:H2O3PCH3 reaction stoichiometry.
3
1
2
31
One P resonance is observed at 13.3 ppm with J ( P-
1
19/117
Sn) satellites, the intensity of which is in agree-
ment with a phosphorus atom being connected to three
1
19
tin atoms through Sn-O bridges. The
Sn NMR
spectrum reveals a badly resolved quartet-like reso-
nance at -279 ppm. Both chemical shifts are very
similar to the isotropic values found in the solid state.
When 2 is (partially) dissolved in C6D6 (the undissolved
species has the appearance of a transparent gel), the
F igu r e 5. Cross-section along the 31P axis and at the
1
19
31
119
Sn resonance frequency of a P- Sn HMQC spectrum
of compound 4 in CD Cl . The middle of the pattern shows
the residual peaks of the three main P resonances (labeled
2
2
3
1
2
31
1
1, 2, 3), while the side resonances show the J ( P-O-
19
H NMR spectrum has sharper lines and reveals the
1
Sn) satellites, with their respective assignment to the
existence of two sets of butyl groups reflecting distinct
main resonance. Each of the three 31P resonance types
shows two coupling splittings, with the values indicated
below the figure.
1
3
chemical environments. The C NMR spectrum con-
firms this. The 31P NMR spectrum reveals at least five
sharp resonances, centered around 13.4 ppm, with broad
tin satellites and superimposed onto a hump resonance.
The quartet-like 1 Sn resonance at -279 ppm turns out
to be an unresolved broad triplet of doublets with
at high temperature to a single one at low temperature
19
(
a kind of “upside-down” coalescence!) to temperature
31
dependences of the P chemical shifts which lead to an
accidental isochrony, enhanced by line broadening due
to the low temperature. The broad quartet-like pattern
2
31
119/117
J ( P-
Hz.
Sn) coupling constants of ca. 160 and 130
1
19
The phenyl phosphonate analogue, 4, displays a better
solubility in less polar solvents (CD2Cl2, CDCl3, and
toluene-d8). All spectra have sharp resonances at room
temperature. The 31P NMR spectrum of 4 in CD2Cl2, at
and below room temperature, shows three major reso-
nances around 1 ppm in the approximate relative ratio
of 2:6:5, together with a minor one, all of them being
of the
Sn spectrum of 4 around -280 ppm was
interpreted as a superposition of three partially unre-
solved doublets of triplets, originating from a single
119
31
Sn and the three above-mentioned P resonances,
making use of a 2D P-119Sn heteronuclear correlation
HMQC spectrum (Figure 5).
The J ( P-O-
Table 4, together with all other H, C, Sn, and
31
2
31
119/117
Sn) coupling data are given in
2
31
119/117
1
13
119
31
flanked by broad unresolved J ( P-O-
Sn) cou-
P
2
31
119
pling satellites (Figure 4). Surprisingly, at 213 K, only
a single, slightly broader resonance remains. We at-
tribute this very unusual merging of three resonances
NMR data. The J ( P-O- Sn) coupling patterns of
3
1
119
the P- Sn HMQC spectrum (Figure 5) as well as the
3
1
P NMR spectrum at 213 K (Figure 4), where the single

2
600 Organometallics, Vol. 20, No. 12, 2001
Ribot et al.
Ta ble 4. 1H, 13C, 31P , a n d 119Sn NMR Da ta of
Com p ou n d 4 a t Room Tem p er a tu r e in CD Cl
2 2
Sch em e 1
A
B
butyl groups
13C
1H
13C
1H
R-CH2
â-CH2b
γ-CH2
CH3
25.9 [746/716]a 0.73 30.09 [700/666]a 1.96
a
2
2
9.92 [718/678]
1.93
9.44 [728/686]a 1.90
27.25
1.23 28.03
27.94
27.87
1.00 27.74
2.06
1.59
1.14
2
2
7.21
7.18
c
b
b
b
of GPC separation of such possible oligomers in com-
pound 4 failed. The impossibility to separate the
26.9 [113]
62
2
2
7.68
7.63
oligomers could be due to an equlibrium, yet such an
equilibrium has to be very slow on the various NMR
13.6
0.67 14.35
1
1
4.24
4.18
3
1
13
time scales, since all the nonequivalent P and
C
resonances, which appear on a narrow spectral band,
phenyl group
13C
1H
2
31
119/117
and the J ( P-O-
Sn) coupling multiplets or
d
ipso
ortho
meta
136.3 [192]
131.9 [9]
satellites observed are basically uncoalesced at room
e
7.65
7.14
temperature and even above. Indeed, high-temperature
127.70 [15]f
31
(
up to 378 K) P NMR in toluene-d8 shows only
1
1
27.63
27.58
appearing and disappearing chemical shift overlappings,
but no coalescence phenomenon that would provide us
support for the existence of an equlibrium between
various oligomers. However, either as a pure tridecam-
er, which appears most likely, or as a mixture of
oligomers, which cannot be totally ruled out, a more
precise solution structure cannot be proposed, since no
crystal structure determination has been possible for 4
(and 2, which are both amorphous solids in their
isolated state), so no starting point to a solution
structure determination is available.
para
31P
130.1
7.31
g
g
g
0.41 [186, 134]
0
0
.37 [188, 131]
.33 [191, 129]
119Sn
h
-279 (td) [188, 131]
a 1 13
119/117
b
2/3 13
J ( C-
Sn) coupling constants. Overlapping, no J ( C-
1
19/117
c
3
13
119/117
Sn) coupling constants visible. Unresolved J ( C-
Sn)
coupling constants. J ( C- P) coupling constant. J ( C-31P)
d 1 13
13
31
31
e 2 13
g 2
coupling constant. f 3J ( C- P) coupling constant. J (31P-O-
1
19
119
Sn) couplings determined from the cross-section at the
Sn
3
1
31
119
resonance frequency of the 2D P-detected P- Sn HMQC
3
1
119
spectrum. td ) triplet of doublets J ( Sn-O-31P).
h
2
119
The P and
Sn NMR data at hand, mainly the
2
31
119
31
J ( P-O- Sn) coupling multiplet analysis using P-
Sn HMQC spectroscopy, do enable us, however, to
precise at least the local coordination environments of
resonance with better resolved J ( P-O-119/117Sn)
satellites is observed, reveal that the satellites with the
larger value (around 190 Hz) have twice the intensity
of those with the smaller value (around 130 Hz). Note
the significantly better resolution in the satellite pat-
2
31
119
119
31
2
the
Sn and P atoms. The triplet of doublets J -
Sn-O- P) coupling pattern in the
119
31
119
(
Sn NMR
spectrum indicates that each tin atom must be bound
to two equivalent (or nearly so) P-O moieties, on one
hand, and to a third one with different environment,
on the other hand. Similarly, the 2:1 intensity ratio in
3
1
119
terns in the P- Sn HMQC spectrum (Figure 5), as
compared to the standard P NMR spectra (Figure 4),
3
1
2
31
117
which is mainly due to the J ( P-O- Sn) satellites
2
31
119/117
in the unresolved J ( P-O-
Sn) satellites of the
2
31
119/117
the J ( P-O-
Sn) coupling satellites flanking the
3
1
standard P NMR spectra being filtered away in the
31
main P resonancessespecially well visible at low
temperature (Figure 4)sindicates that each phosphorus
atom must be bound to two equivalent Sn-O moieties,
on one hand, and to a third nonequivalent one, on the
other hand. The most likely bonding schemes A and B
for Sn and P, respectively, compatible with these pat-
terns, are given in Scheme 1.
3
1
119
P- Sn HMQC spectrum. The approximate 2:6:5
3
1
splitting of the resonances in the P spectrum also
1
3
exists in the C NMR spectrum for most of its reso-
nances. The complete assignment of the C resonances
1
3
1
and the corresponding H resonances was achieved by
13
2
D heteronuclear 1H- C HMQC and HMBC experi-
1
ments, together with a 2D homonuclear H TOCSY
experiment, which clearly revealed the presence of two
At the level of the phosphorus atom, the bonding
scheme corresponds to a “111” motif with local Cs
symmetry.
“
kinds” of butyl groups, given as A and B in Table 4.
The R-butyl H resonances again reveal a splitting
similar to that of the P spectrum. Importanly, the
relative intensity ratio (2:6:5) of the P (and C)
resonances was found perfectly reproducible for several
synthesis batches.
Solu tion Sta te Bon d in g P a tter n s a n d Str u c-
tu r es. The mean molar mass equivalent to 12.9 mon-
omeric Bu2Sn(O3PPh) units, combined with the inde-
pendent data of 2:6:5 demultiplication, also observed in
CDCl3, of most 31P, C, and even 1H resonances, all
these results being obtained in the same concentration
range, highly suggests 4 to be a tridecamer, [Bu2Sn(O3-
PPh)]13. The alternative, i.e., a mixture of several closely
related oligomers, seems less likely, as several attempts
1
2
119
31
The resolved J ( Sn-O- P) multiplets, as well as
3
1
119
the absence of low-frequency shift in the Sn chemical
3
1
13
shift around -280 ppm upon temperature decrease and
concentration increase, show a very stable structural
motif with no tendency to chemical exchange observable
on any of the NMR time scales available. The simulta-
neous presence of the two structural motifs of Scheme
1
is in agreement with the 1P:1Sn stoichiometric ratio
of the basic Bu2Sn(O3PR) unit of compounds 2 and 4.
13
(62) GPC equipment and operating contidions: Pump (Waters 510)
and refractometer (Waters RI-410). The columns were µ-styragel
4
3
(
porosity 10 , 10 , and 500 Å; grain size 10 µm; length 30 cm). The
-1
solvent was THF with a flow rate of 1 mL‚min ; 50 µL of 1 wt %
solutions was injected.

Di-n-butyltin Methyl- and Phenylphosphonates
Organometallics, Vol. 20, No. 12, 2001 2601
A global key observation is that at room temperature
proton on the oxygens of P-O-Sn moieties possible,
which results necessarily in a dynamic network of
closing and opening O-Sn bonds compatible with the
all four compounds, the 1P:1Sn compounds 2 and 4 as
1
19
well as the 2P:1Sn compounds 1 and 3, exhibit a
Sn
resonance in the same 1 Sn chemical shift area around
280 ppm, which strongly suggests that the basic
19
2
119
31
loss of observable J ( Sn-O- P) couplings on both
1
19
31
-
the Sn and P NMR time scales, as indeed observed.
By contrast, the source of stereochemical stability of
compound pair 2/4 results from the fact that all three
oxygen atoms of a phosphonate ligand are bound to tin
atoms and cannot undergo such a substitution.
coordination motifs around the tin atom must be very
similar, despite the presence of one hydrogen on each
phosphonate ligand in compounds 1 and 3 but none in
2
and 4. On the other hand, the very high similarity of
1
19
119
the Sn chemical shift of 1 at low temperature and of
Noteworthy is that the Sn chemical shift of the five-
1
19
its Sn isotropic chemical shift in the crystalline state,
around -350 ppm, lead us to propose that the low-
temperature solution structure of 1 mainly consists of
the aggregation through “5+2” coordination at the tin
atoms of the basic dimeric units also observed in the
crystalline state. The 1 Sn chemical shift of 1 around
coordinate Bu SnO coordination motif, involving phos-
2
3
phonate ligands, appears around -280 ppm, ca. 60-80
ppm to lower frequency, as compared with that of
dimeric bis(dicarboxylatotetraorganodistannoxanes) of
4
the type {[R′COOSnR ] O} . This is quite acceptable,
2
2
2
19
considering that a phosphonate contains one oxygen
more than a carboxylate ligand and that the phosphorus
atom has more electrons and a wider electron cloud than
the carboxylate carbon atom. This must result in a
higher global shielding of the tin nucleus, conforming
-
280 ppm is representative of the basic dimeric unit
with pure five-coordination at tin, in R2SnO3 distorted
trigonal bipyramidal configuration, being the dominant
species in the dynamic equilibrium at room tempera-
ture. Since at low and room temperatures a single
averaged 1 Sn resonance is observed, the equilibrium
between the “5+2” coordinated aggregates of dimeric
units and the isolated purely five-coordinate dimers
must necessarily be fast on the 1 Sn NMR time scale.
Such an equilibrium is responsible for the absence of
1
19
to the
Sn chemical shifts observed at significantly
19
lower frequency.
Exp er im en ta l Section
2
Syn th eses. Di-n-butyltinoxide, Bu SnO, MePO(OH) , and
19
2
2
31
119/117
PhPO(OH) were purchased from respectively J anssen Chim-
2
J ( P-
Sn) splittings, as it causes the phosphonate
ica (17.936.88), Fluka (64259), and Acros (13079-1000).
Com p ou n d s 1 a n d 2. Di-n-butyltin oxide (1.62 g, 6.5 mmol)
and an excess (5 mL) of 1-propanol were refluxed in 125 mL
of benzene for 4 h. The ternary azeotrope benzene/water/
propanol was removed using a Dean Stark funnel. After cooling
the reaction mixture to room temperature, a solution of 1.25
to move from one tin to another.
The same argument holds for compound 3. Further-
more, the similar 1 Sn chemical shifts, in the same
range around -280 ppm, at room temperature strongly
suggest an analogous R2SnO3 coordination motif for
compounds 2 and 4. Supporting arguments are (i) that
19
g (13 mmol), for 1, or 0.625 g (6.5 mmol), for 2, of MePO(OH)
2
2
119
in a mixture of 20 mL of benzene and 20 mL of methanol was
added slowly to the solution. The reaction mixture was stirred
at room temperature for 18 h. The reaction mixture was then
filtered off, and the solvents were removed from the filtrate
under reduced pressure. Only compound 1 could be obtained
as a crystalline compound. It was recrystallized from a 1:1
benzene/methanol mixture.
the motifs of Scheme 1 proposed from the J ( Sn-O-
3
1
P) coupling patterns for 4 are compatible with the R2-
2
119
31
SnO3 motif, (ii) that the J ( Sn-O- P) coupling
values of 1 in the solid state are in the same value range
and obey similar coupling patterns as in 4 in solution,
and (iii) that all the 1J ( C- Sn) coupling values,
which range from 700 to 750 Hz, indicate C-Sn-C
angles between 138° and 141°, fully compatible with the
proposed distorted trigonal bipyramid tin environ-
ment.63 Such a local geometry is similar to the one
13
119
Com p ou n d 1. Yield: 65%; mp > 350°. Anal. Found: Sn,
28.8; C, 28.3; H, 6.2; P, 15.8. Calcd for Sn C H O P : Sn,
2
20 52 12
4
28.08; C, 28.39; H, 6.21; P, 14.64. NMR (C
6 6 3
D /CD OD),
chemical shifts in ppm, coupling constants in Hz: 1H: 0.94
(
3H, t, CH
3
butyl); complex patterns centered at 1.37 (2H,
proposed in the late 1960s by Ridenour et al. from IR
2
1
119/117
and 119Sn M o¨ ssbauer data on [Bu2Sn(O3PR)]n (R )
γ-CH
2
); 1.54 (2H, R-CH
2
, J ( H-
2
Sn) 88); 1.73 (2H, â-CH ,
3
1
1
119/117
2
1
31
2
7a
J ( H-
Sn) 106); 1.36 (3H, d, J ( H- P) 18, CH
3
-P).
C6H13, CH2C6H5, C8H17). Finally, the five-coordination
of tin implies triply bridging phosphonates for com-
pounds 2 and 4, but an equal amount of terminal and
doubly bridging phosphonates for compounds 1 and 3,
as suggested by 31P MAS NMR and actually proved by
X-ray data for 1.
3
3
13
119/117
butyl); 27.0 (γ-CH , J ( C-
1 13
C: 13.6 (CH
3
2
Sn) 110); 27.4
2
13
119/117
119/117
(â-CH
2
, J ( C-
Sn) 24); 27.7 (R-CH
2
, J ( C-
119
Sn) 732/
1
13
31
31
7
01); 13.8 (d, J ( C- P) 144, CH
Com p ou n d 2. Yield: 64%; mp > 350°. Anal. Found: Sn,
6.7; C, 33.3; H, 6.2; P, 10.4. Calcd for SnC P: Sn, 36.30;
H (CDCl /CD OD): broad
3
-P). P: 21.6. Sn: -278.
3
9
21 3
H O
1
C, 33.06; H, 6.49; P, 9.47. NMR
3
3
The only major difference between the compound
pairs 2/4 and 1/3 lies in the dramatic contrast between
the high stereochemical lability of the latter as opposed
to the high stereochemical stability of the former. It is
proposed that the key to this difference is the proton
bound to the phosphonate ligand in the compound pair
resonances centered at 0.87, 1.29, 1.64 for Bu; 1.29 (3H, d,
2
1
31
31
119
1
J ( H- P) 17, CH
3H, t, CH butyl); complex patterns centered at 2.19, 2.06, 1.85,
.73, 1.41, and 1.23 ppm (butyl CH
3
-P). P: 13.3. Sn: -279. H (C
6 6
D ): 0.94
(
3
2
1
1
2
’s); 1.36 (3H, d, J ( H-
-P). C: 14.3 (several overlapping lines, CH
butyl); 27.9 (several overlapping broad lines without visible
3
1
13
P) 17.4, CH
3
3
1
13
31
satellites), 27.0, 26.6, 26.0 (butyl CH
2
’s); 15.0 (d, J ( C- P)
1
/3. Thus, this acidic proton can interact intra- or
31
119
2
1
49, CH
3
31
-P). P: 13.5, 13.3, 13.0, 12.9. Sn: -280 (td, J -
intermolecularly with oxygens bound to tin atoms and
be transferred to them, henceforth destabilizing the
O-Sn bonds, as observed. In other terms, this should
make an easy electrophilic substitution of tin by the
119
(
Sn- P) 160 and 130).
Com p ou n d s 3 a n d 4. Di-n-butyltin oxide (3.24 g, 13 mmol)
and an excess (10 mL) of 1-propanol were refluxed in 250 mL
of benzene for 4 h. The ternary azeotrope benzene/water/
propanol was removed using a Dean Stark funnel. After cooling
the reaction mixture to room temperature, a solution of 4.11
(63) Lockhart, T. P.; Manders, J . J .; Zuckerman, J . J . J . Am. Chem.
Soc. 1985, 107, 4546.
2
g (26 mmol) for 3, or 2.05 g (13 mmol) for 4, of PhPO(OH) in

2
602 Organometallics, Vol. 20, No. 12, 2001
Ribot et al.
tion correction was applied.64 The structure was solved using
the direct method with the SHELXS program.65 Successive
Fourier maps were used to locate all non-H atoms. The H
atoms of the butyl and methyl were placed geometrically at
the end of each cycle. A unique isotropic thermal parameter
was used for all the H atoms. The H atoms of the hydrogeno-
phosphonate could not be located. Full matrix least-squares
refinement, based on F, of atomic parameters, of anisotropic
thermal parameters for non-H atoms, and of the unique
isotropic thermal parameter for H atoms was carried out with
Ta ble 5. Cr ysta llogr a p h ic Da ta a n d Refin em en t
Deta ils for 1
formula
M
Sn2C20H52O12P4
846.0
cryst color, habit
cryst size
cryst syst
colorless, ∼platelet
0.3 × 0.3 × 0.1 mm
triclinic
3
space group
unit cell dimens
P 1h (no. 2)
a ) 8.612(3) Å
b ) 9.927(4) Å
c ) 10.584(6) Å
R ) 100.37(4)°
â ) 93.94(3)°
γ ) 103.04(3)°
6
6
the CRYSTALS programs. The atomic scattering factors were
provided by CRYSTALS.66 Final refinement details are given
in Table 5. The numbering scheme employed is shown in
Figure 1.
3
V
Z
861.4(7) Å
Solid Sta te NMR Exp er im en ts. The 119Sn and 31P MAS
(magic angle spinning) NMR experiments have been performed
on a Bruker MSL300 spectrometer (111.92 and 121.49 MHz
1
-
3
Dc
F(000)
1.63 g cm
428
diffractometer
radiation (λ)
Enraf-Nonius CAD-4
Mo KR (0.71069 Å);
119
31
for
Sn and P, respectively) equipped with a 4 mm high-
1
19
speed locked Bruker probe. For Sn, the spectral width, pulse
graphite monochromator
-
1
durations, and recycling delays were 200 000 Hz (∼1800 ppm),
µ
T
16.9 cm
1
-1.5 µs (<30°), and 15 s, respectively. Typically, 500-4000
room temperature (22 °C)
ω-2θ
scan type
scan width
θ range for data collection
hkl ranges
no. of reflns collected
no. of unique reflns
abs corr
transients were accumulated in order to achieve reasonable
signal-to-noise ratios. 1 Sn chemical shifts are quoted relative
19
0.8 + 0.345 tan(θ)°
1-30°
4
to Me Sn, using solid tetracyclohexyltin (δiso ) -97.35 ppm)
67 31
0f +12; -13 f +13; -14 f +14
5335
as a secondary external reference. For P, the spectral width,
pulse durations, and recycling delays were 30 000 Hz (∼250
ppm), 1-2 µs (<30°), and 10-15 s, respectively. A total of 16-
5024 (Rint ) 0.06)
6
4
DIFABS (min. 0.91; max. 1.00)
4
00 transients were recorded depending on the sample and
no. of data/restraints/params 4146 [I > 3.00σ(I)]/16/174
spinning rate. High-power proton decoupling was switched on
refinement method
full-matrix least squares on F
1
31
during acquisition to remove the H- P dipolar interaction,
secondary extinction param
final indices: R, Rw
goodness of fit on F
residual electron density,
min./max.
66
a
which was not fully averaged to zero by the MAS and can
0.0723; 0.0861
1.075
-3.15/+2.89 e Å
dramatically broaden the resonances, especially at low spin-
-
3
31
3
ning rate. P chemical shifts are quoted relative to 85% H -
4 4 2 4
PO , using solid NH (H PO ) (δiso ) 0.95 ppm) as a secondary
a
R ) ∑||Fo| - |Fc||/∑|Fo|; Rw ) [∑(w|Fo - Fc| )/∑(wFo )]1/2, where
2
2
external reference. For both nuclei, at least two experiments,
with sufficiently different spinning rates, were run in order
to identify the isotropic chemical shifts. The spinning frequen-
cies were stabilized to (5 Hz.
2
2
w ) w′[1 - (||Fo| - |Fc||/6σ(Fo)) ] and w′ ) 1/∑rArTr(X) with 3
coefficients 7.64, 3.45, and 5.51 for a Chebyshev series, for which
X is Fc/Fc (max.).
1
19
Sn and 31P spectra were simulated with WINFIT
The
software.68 The principal components of the shielding tensors
a mixture of 50 mL of benzene and 50 mL of methanol was
added slowly to the solution. The reaction mixture was stirred
at room temperature for 18 h. The reaction mixture was then
filtered off, and the solvents were removed from the filtrate
under reduced pressure.
6
9
were extracted using the Herzfeld and Berger approach. They
are reported, following Haeberlen’s convention as the isotropic
chemical shift (δiso ) -σiso), the anisotropy (ú ) σ33 - σiso), and
5
9,70
the asymmetry (η ) |σ22 - σ11|/|σ33 - σiso|).
The accuracy of
δ
iso corresponds to the digital resolution ((0.5 and (0.1 ppm
Com p ou n d 3. Yield: 69%; mp 183-185°. Anal. Found: Sn,
for 1 Sn and P, respectively). The accuracy of ú was esti-
19
31
2
2
1.8; C, 43.8; H, 5.5; P, 12.6. Calcd for SnC20
H
30
O
6
P
2
: Sn,
): 0.78 (3H,
2
); 1.56 (2H, m,
1
19
31
1
mated to (10 and (4 ppm for Sn and P, respectively. The
accuracy on η is (0.05.
1.70; C, 43.90; H, 5.54; P, 11.32. H (CD
3 4
OD/CCl
t,CH
â-CH
ortho). C: 14.6 (CH
3
); 1.20 (2H, m, γ-CH ); 1.44 (2H, m,R-CH
2
2
Solu tion NMR Exp er im en ts. The spectra were recorded
at 303 K, unless otherwise stated, on a Bruker AMX500
instrument, equipped with a triple resonance inverse probe-
); 7.31 (2H, m, meta); 7.42 (1H, m, para); 7.69 (2H, m,
1
3
3
13
119/117
3
); 27.9 (γ-CH
2
, J ( C-
Sn) 112); 28.2
2
13
119/117
1
13 119/117
(
â-CH
2
, J ( C-
Sn) 23); 29.3 (R-CH
2
, J ( C-
Sn) 700/
head (TBI) with 1H, P, or
31
119
Sn and broad band channels,
3
13
31
6
86); 129.1 (meta, J ( C- P) 14); 132.0 (para); 132.3 (ortho,
13 31 1 13 31 31 119
1
2
operating at 500.13, 125.76, 202.46, and 186.50 MHz, for H,
Sn, respectively. All 1D spectra and 2D
homonuclear H TOCSY as well as the 2D heteronuclear
J ( C- P) 11); 135.2 (ipso, J ( C- P) 190). P: 10.4. Sn:
1
3
31
119
C, P, and
-
275.
1
Com p ou n d 4. Yield: 67%; mp > 350°. Anal. Found: Sn,
8.3; C, 43.0; H, 5.9; P, 8.0. Calcd for SnC14H O P: Sn, 30.51;
23 3
C, 43.22; H, 5.97; P, 7.96. NMR data: see Table 4.
Cr ysta llogr a p h y. Single crystals of 1 were obtained after
cold crystallization of 100 mg of the crude compound in a
1
13
ge- H- C HMQC and HMBC were obtained from standard
2
pulse programs in the Bruker library. The 2D double hetero-
nuclear 31P- Sn HMQC spectrum was recorded with
119
31
P
detection at 263 K, and the delay for heteronuclear coupling
evolution was set at 3.6 ms, with 1H decoupling throughout.
6 6
mixture of 4 mL of C H and 4 mL of MeOH. A colorless
crystal, suitable for X-ray diffraction, was sealed in a Lindman
glass capillary tube, and intensity data were collected at room
temperature on an Enraf-Nonius CAD4 diffractometer fitted
with graphite-monochromatized Mo KR radiation (λ ) 0.71069
Å). Details concerning the crystallographic data collection and
structure determination are given in Table 5. Cell dimensions
were determined from 25 reflections (17° < θ < 20°) dispersed
in reciprocal space. Two standard reflections were monitored
every hour during data collection and showed a decay of 36%;
the data were scaled accordingly. Intensities were corrected
for Lorentz and polarization effects, and an empirical absorp-
(
(
64) Walker, N.; Stuart, D. Acta Crystallogr. Sect. A 1983, 39, 158.
65) Sheldrick, G. M. SHELXS-86, Program for Automatic Solution
of Crystal Structure; University of G o¨ ttingen: G o¨ ttingen, Germany,
986.
66) Watkin, D. J .; Prout, C. K.; Carruthers, J . R.; Betteridge, P.
1
(
W. CRYSTALS issue 10; Chemical Crystallography Laboratory, Uni-
versity of Oxford: Oxford, U.K., 1996.
(67) Reuter, H.; Sebald, A. Z. Naturforsch. 1992, 48b, 195.
(68) Massiot, D.; Thiele, H.; Germanus, A. Bruker Rep. 1994, 140,
4
3.
(
(
69) Herzfeld, J .; Berger, A. E. J . Chem. Phys. 1980, 73, 6021.
70) Harris, R. K.; Lawrence, S. E.; Oh, S. W. J . Mol. Struct. 1995,
347, 309.

Di-n-butyltin Methyl- and Phenylphosphonates
Organometallics, Vol. 20, No. 12, 2001 2603
F T-IR Sp ectr oscop y. FT-IR spectra were recorded on a
Nicolet Magna-IR 550 spectrometer. Solid samples were
dispersed in spectroscopic grade KBr pellets.
indebted to the Fund for Scientific Research Flanders
(Belgium, grant no. G.0192.98) for financial support.
J .C.M. is a Postdoctoral Fellow of the Fund for Scientific
Research Flanders (F.W.O.) (Belgium). F.R., C.S., M.B.,
and R.W. are indebted to the Flemish Ministry of
Education and the French Ministries of Foreign Affairs
and Education, Research and Technology for the alloca-
tion of a Tournesol Grant (no. 99.091).
Mola r Ma ss Deter m in a tion by Va p or P r essu r e Os-
m om etr y. The molecular mass measurements were performed
with a Knauer vapor pressure osmometer No. 11.00, in
chloroform at 43 °C (( 0.01 °C). The calibration was performed
6 5 6 5
with benzil (C H COCOC H ). The accuracy of the determi-
nation was estimated from two independent measurements,
each being performed with five different concentrations.
Ch em ica l An a lyses. Sn, C, H, and P elemental analyses
were performed at the “Service Central d’Analyse” in Vernai-
son (France).
Su p p or tin g In for m a tion Ava ila ble: Further details of
the structure determination including bond distances and
2 3 2 2
angles and thermal parameters for {Bu Sn(HO PMe) } , 1, as
3
1
well as the P MAS NMR spectra of compounds 2, 3, and 4
and the 1 Sn MAS NMR spectra, with simulations, of com-
pounds 1, 2, 3, and 4. This material is available free of charge
via the Internet at http://pubs.acs.org.
Ack n ow led gm en t. The authors thank Dr. J . Vais-
sermann (Centre de R e´ solution Structurale, Bat. F-E4,
UPMC, Paris, France) for solving the X-ray structure
and J . Maquet for her precious assistance in solid state
19
1
19
31
Sn and P MAS NMR. M.B., R.W., and F.A.G.M. are
OM010140X