Phospha-scorpionate complexes by click chemistry using phenyl azide and ethynylphosphine oxides

Article abstract of DOI:10.1021/om800127h

The copper-catalyzed Click reaction of phenyl azide with ethynylphosphine oxides provides new P-substituted triazoles. With tris(ethynyl)phosphine oxide this route affords a versatile scorpionate ligand that coordinates to RhCl ₃ as a tripodal N ligand. Upon reduction, the same ligand can act as a P donor to W(CO)₅. Both coordination modes can be combined, giving access to a bimetallic Mo/W complex.

Full text of DOI:10.1021/om800127h

3210
Organometallics 2008, 27, 3210–3215
Phospha-Scorpionate Complexes by Click Chemistry using Phenyl
Azide and Ethynylphosphine Oxides
Sander G. A. van Assema,† Cornelis G. J. Tazelaar,† G. Bas de Jong,† Jan H. van
Maarseveen,‡ Marius Schakel,† Martin Lutz,§ Anthony L. Spek,§ J. Chris Slootweg,† and
Koop Lammertsma*,†
Department of Organic and Inorganic Chemistry, Faculty of Sciences, VU UniVersity Amsterdam,
De Boelelaan 1083, NL-1081 HV, Amsterdam, The Netherlands, Van ‘t Hoff Institute of Molecular Sciences,
UniVersity of Amsterdam, Nieuwe Achtergracht 129, NL-1018 WS, Amsterdam, The Netherlands, and BijVoet
Center for Biomolecular Research, Crystal and Structural Chemistry, Utrecht UniVersity, Padualaan 8,
NL-3584 CH, Utrecht, The Netherlands.
ReceiVed February 13, 2008
The copper-catalyzed Click reaction of phenyl azide with ethynylphosphine oxides provides new
P-substituted triazoles. With tris(ethynyl)phosphine oxide this route affords a versatile scorpionate ligand
that coordinates to RhCl3 as a tripodal N ligand. Upon reduction, the same ligand can act as a P donor
to W(CO)5. Both coordination modes can be combined, giving access to a bimetallic Mo/W complex.
heavily in a diversity of fields.7–9 Phospha-substituted triazoles
Introduction
are rare10 but add an extra dimension, as in the O,O- and N,O-
chelating 1a,b.11 Also illustrative is ClickPhos (2), which is an
effective ligand in Pd-catalyzed Suzuki-Miyaura coupling12,13
and is synthesized by “P-substitution” of the triazole ring.
Scorpionates are tripodal N ligands ubiquitous in both
coordination chemistry and homogeneous catalysis.1 In these
ligands two pyrazolyl groups form a chelate, while the third
(pyrazolyl) donor may act like a “scorpion tail” grabbing its
prey as it complexes the common metal. Their functionality was
extended only recently with hetero substituents2 on the pyrazole
rings to enable coordination on the apex face of the molecular
frame. Commonly the apex of scorpionates consists of anionic
borates1 or neutral hydrocarbons.3 Here we report on (bi)metallic
complexes of novel scorpionates having a phosphorus apex and
triazoles as N ligands.
Results and Discussion
Triazoles are readily obtained by a Huisgen 1,3-dipolar
cycloaddition4 of organic azides to alkynes. The CuI-catalyzed
version of this click reaction5 tolerates many functional groups
(e.g., esters, acids, alkenes, alcohols, and amines) and yields
only the 1,4-disubstituted derivatives,6 which are exploited
Phospha-substituted 1,2,3-triazoles can be obtained directly
by the stereoselective cycloaddition of azides to P-substituted
alkynes, but protection of the phosphorus center is necessary
(7) (a) Wu, P.; Feldman, A. K.; Nugent, A. K.; Hawker, C. J.; Scheel,
A.; Voit, B.; Pyun, J.; Fre´chet, J. M. J.; Sharpless, K. B.; Fokin, V. V.
Angew. Chem., Int. Ed. 2004, 43, 3928–3932. (b) Lee, L. V.; Mitchell,
M. L.; Huang, S.-J.; Fokin, V. V.; Sharpless, K. B.; Wong, C.-H. J. Am.
Chem. Soc. 2003, 125, 9588–9589. (c) Binder, W. H.; Kluger, C. Curr.
Org. Chem. 2006, 10, 1791–1815. (d) Bock, V. D.; Hiemstra, H.; van
Maarseveen, J. H. Eur. J. Org. Chem. 2006, 51–68.
* To whom correspondence should be addressed. Fax: +31-20-5987488.
E-mail: K.Lammertsma@few.vu.nl.
† VU University Amsterdam.
‡ University of Amsterdam.
§ Utrecht University.
(1) (a) Trofimenko, S. Scorpionates: The Coordination Chemistry of
Polypyrazolylborate Ligands; Imperial College Press: London, 1999. (b)
Trofimenko, S. Chem. ReV. 1993, 93, 943–980. (c) Trofimenko, S. J. Chem.
Educ. 2005, 82, 1715–1720.
(8) (a) Kolb, H. C.; Sharpless, K. B. Drug DiscoVery Today 2003, 8,
1128–1137. (b) Lewis, W. G.; Green, L. G.; Grynszpan, F.; Radic´, Z.;
Carlier, P. R; Taylor, P.; Finn, M. G.; Sharpless, K. B Angew. Chem., Int.
Ed. 2002, 41, 1053–1057.
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Chem. Commun. 2007, 1524–1526. (b) Silva, R. M.; Gwengo, C.; Lindeman,
S. V.; Smith, M. D.; Gardinier, J. R. Inorg. Chem. 2006, 45, 10998–11007.
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Dalton Trans. 2005, 635–651.
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J. L.; Fre´chet, J. M. J.; Hawker, C. J. J. Am. Chem. Soc. 2006, 128, 12084–
12085, and references therein. (b) van Steenis, D. J. V. C.; David, O. R. P.;
van Strijdonck, G. P. F.; van Maarseveen, J. H.; Reek, J. N. H. Chem.
Commun. 2005, 4333–4335.
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Huisgen, R.; Szeimies, G.; Moebius, L. Chem. Ber. 1967, 100, 2494–2507.
(c) Huisgen, R. Pure Appl. Chem. 1989, 61, 613–628.
(10) A few uncatalyzed reactions are known: (a) Hall, R. G.; Trippett,
S. Tetrahedron. Lett. 1982, 23, 2603–2604. (b) Balthazor, T. M.; Flores,
R. A. J. Org. Chem. 1980, 45, 529–531. (c) Shen, Y.; Zheng, J.; Xin, Y.;
Lin, Y.; Qi, M. J. Chem. Soc. Perkin Trans. 1 1995, 8, 997–999.
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Chem., Int. Ed. 2000, 39, 3321–3324.
(5) (a) Kolb, H. C.; Finn, M. G.; Sharpless, K. B. Angew. Chem., Int.
Ed. 2001, 40, 2004–2021. (b) Rostovtsev, V. V.; Green, L. G.; Fokin, V. V.;
Sharpless, K. B. Angew. Chem., Int. Ed. 2002, 41, 2596–2599.
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(b) Rodionov, V. O.; Fokin, V. V.; Finn, M. G. Angew. Chem., Int. Ed.
2005, 44, 2210–2215. (c) For 1,5-disubstituted 1,2,3-triazoles see: Fokin,
V. V.; Jia, G.; Zhang, L.; Chen, X.; Xue, P.; Sun, H. H. Y.; Williams,
I. D.; Sharpless, K. B. J. Am. Chem. Soc. 2005, 127, 15998–15999.
(12) Li, D.; Gao, W.; Dai, Q.; Zhang, X. Org. Lett. 2005, 7, 4907–
4910.
(13) The Ph2PCH2-substituted 1,2,3-triazole ClickPhine behaves as an
effective P,N-ligand: Detz, R. J.; Heras, S. A.; de Gelder, R.; van Leeuwen,
P. W. N. M.; Hiemstra, H.; Reek, J. N. H.; van Maarseveen, J. H. Org.
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10.1021/om800127h CCC: $40.75
2008 American Chemical Society
Publication on Web 05/24/2008

Phospha-Scorpionate Complexes by Click Chemistry
Organometallics, Vol. 27, No. 13, 2008 3211
Scheme 1. Syntheses of P-Substituted 1,2,3-Triazoles 4
Scheme 2. Syntheses of Complexed Phospha-Scorpionates
6-8
Figure 1. Displacement ellipsoid plot of 6 drawn at the 50%
probability level. Hydrogen atoms and disordered solvent molecules
are omitted for clarity. Selected bond lengths (Å) and angles (deg):
Rh1-Cl1 ) 2.3187(12), Rh1-N31 ) 2.057(4), P1-O1 ) 1.463(3),
P1-C11 ) 1.781(5), N11-N21 ) 1.352(5), N21-N31 ) 1.308(5),
N11-C21 ) 1.354(6), N11-C31 ) 1.435(6), N31-C11 )
1.369(6), C11-C21 ) 1.364(6); O1-P1-Rh1 ) 179.42(14),
O1-P1-C11 ) 116.8(2), C11-P1-C12 ) 99.9(2), Rh1-N31-N21
) 125.1(3), N31-C11-C21 ) 106.0(4).
structure is propeller-shaped, with the three phenyl groups
rotated by 37.9(3), 16.2(3), and 17.7(3)° in the same direction
from the planar triazole rings. The PdO group and the Rh
transition metal are on the axle of the propeller (O1-P1-Rh1
) 179.42(14)°), and the angles around Rh (88.17(15)-92.55(4)°)
are close to the ideal 90° for an octahedron.
to prevent the Staudinger reaction to occur.13,14 The thus
required phosphinoyl-ethynes 3a-d, having one to three
terminal acetylenic groups, were synthesized by reacting
RnP(dO)X3-n (R ) Ph, NiPr2; X ) Cl, Br; n ) 0-2) with
Me3SiCt CMgBr, followed by desilylation using nBu4NF.
Subsequent addition of phenyl azide under click conditions
(CuSO4 · 5H2O, sodium ascorbate, H2O/tBuOH)5b results ex-
clusively in the 1,4-disubstituted 1,2,3-triazoles 4a-d, which
are easily obtained in pure form after column chromatography
(>70% yield; Scheme 1).
An interesting application is the reduction of 4a (R ) Ph, n
) 2; δ(31P) 17.4) in PhSiH3 at 100 °C (12 h) to give the novel
ClickPhos ligand12 2a (R ) Ph, no Ar; δ(31P) -32.4) as a
colorless solid in 94% isolated yield. Phospha-scorpionate 4d
(δ(31P) -5.7), obtained in 72% yield from tris(ethynyl)phos-
phine oxide 3d (δ(31P) -56.8) by a triple click reaction, is also
amenable to reduction with PhSiH3 at 100 °C (48 h), affording
the corresponding phosphine 5 as an air-sensitive, off-white solid
(90% yield; δ(31P) -83.7).
Reaction of phosphine 5 with [W(CO)5(MeCN)] in THF
(room temperature, 16 h) gave the stable W complex 7 (86%
yield, mp 211-212 °C; Scheme 2) with the transition-metal
group connected to the phosphorus atom instead of to the triazole
1
rings, as evidenced by the J(P,W) coupling constant of 257.2
Hz for the 31P NMR signal at -40.6 ppm. The structure of 7
was established unequivocally by a single-crystal X-ray analysis
(Figure 2), which shows an octahedral arrangement for the W
metal center surrounded by five CO ligands and the apex P of
ligand 5 (W1-P1 ) 2.4829(10) Å). The P-C bond lengths
are in the expected range, and the nitrogens of the triazole rings
are mostly facing outward.
Bimetallic complexation of scorpionate 5 can also be realized.
Reaction of 7 with [(C7H8)Mo(CO)3] in THF (room temperature,
16 h) results in the desired W/Mo-bimetallic complex 8 as a
red solid (74% yield; δ(31P) -62.8, 1J(P,W) ) 261.1 Hz;
Scheme 2). Mo(CO)3 complexation to 7 causes an upfield shift
of 22.2 ppm for the 31P NMR signal and of 4.5 ppm for the
axial carbonyl signal of the W(CO)5 group (δ(13C) 194.6,
2J(C,P) ) 25.5 Hz); the 1H NMR signal of the triazole hydrogen
is not influenced (δ(1H) 8.59 for 8 vs 8.53 for 7). The X-ray
structure of 8 (Figure 3) shows the binding of the Mo(CO)3
unit to the 3-position of the three triazoles analogous to Rh
complex 6. This coordination elongates the (cage) C-N bonds
(C1-N3: 8, 1.374(4)-1.384(4) Å; 7, 1.351(4)-1.371(4) Å) and
slightly reduces the sum of the angles around P (8, 298.91°; 7,
303.34°) that contributes to the shielding of the 31P NMR
signal.16 A near-octahedral arrangement is observed for both
metals, with the Mo-centered one being the most distorted: i.e.,
the average N-Mo-N, C-Mo-C, and N-Mo-C angles are
81.2, 86.5, and 96.1°, respectively.
Both novel scorpionates, 4d and 5, are susceptible to
transition-metal complexation, but in different manners. Phos-
phine oxide 4d functions as a tripodal N ligand and coordinates
to rhodium trichloride in refluxing THF/EtOH to give the novel
6 as an orange solid (65% yield; Scheme 2), thereby behaving
like the related tris(pyrazolyl)phosphine oxides15 that complex
to CuI,15b ZnCl2,15b TlI,15c and Mo(CO)3.15d The Rh phospha-
scorpionate complex 6 shows a 31P NMR signal at -9.7 ppm
1
and a deshielded H NMR signal at 10.00 ppm (cf. 4d, 8.87
ppm) for the three triazole ring protons. A single-crystal X-ray
structural analysis confirmed the coordination of RhCl3 to the
3-position of the three triazole rings (Figure 1). The molecular
(14) (a) Staudinger, H.; Meyer, J. HelV. Chim. Acta 1919, 2, 635–646.
(b) Saxon, E.; Bertozzi, C. R. Science 2000, 287, 2007–2010.
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54, 2710–2714. (b) Tokar, C. J.; Kettler, P. B.; Tolman, W. B. Organo-
metallics 1992, 11, 2737–2739. (c) LeCloux, D. D.; Tokar, C. J.; Osawa,
M.; Houser, R. P.; Keyes, M. C.; Tolman, W. B. Organometallics 1994,
13, 2855–2866. (d) Joshi, V. S.; Kale, V. K.; Sathe, K. M.; Sarkar, A.;
Tavale, S. S.; Suresh, C. G. Organometallics 1991, 10, 2898–2902.
(16) Couzijn, E. P. A.; Ehlers, A. W.; Slootweg, J. C.; Schakel, M.;
Krill, S.; Lutz, M.; Spek, A. L.; Lammertsma, K. Chem. Eur. J. 2008, 14,
1499–1507.

3212 Organometallics, Vol. 27, No. 13, 2008
Van Assema et al.
curs to the phosphorus apex face, to the three triazole rings,
and even to both sites when two metals are used. The present
results demonstrate a simple and effective molecular design to
novel scorpionates with ample opportunities for expansion and
application.17 Homogenous catalysis is an obvious area to
explore their potential, but also the communication between the
metallic centers is an intriguing facet for further study.
Experimental Section
General Procedures. All experiments were performed under an
atmosphere of dry nitrogen. Solvents were purified, dried, and
degassed by standard techniques. Phenyl azide,18 tricarbonyl(cy-
cloheptatriene)molybdenum,19 W(CO)5(acetonitrile),20 and 3c21c
have been prepared according to literature procedures. NMR spectra
were recorded at 298 K on a Bruker Avance 250 or on a Bruker
Avance 400 spectrometer (1H, 13C, and 31P; 85% H3PO4) and
referenced internally to residual solvent resonances (1H 7.26 ppm
1
and 13C{1H} 77.16 ppm for CHCl3; H 5.32 ppm and 13C{1H}
53.8 ppm for CDHCl2; 1H 7.16 ppm and 13C{1H} 128.06 ppm for
C6D5H; 1H 2.49 ppm and 13C{1H} 39.5 ppm for DMSO-d6). High-
resolution mass spectra (HR EI-MS) were recorded on a Finnigan
Mat 900 (70 eV) and fast atom bombardment (HR FAB-MS) mass
spectrometry was carried out using a JEOL JMS SX/SX 102A four-
sector mass spectrometer, coupled to a JEOL MS-MP9021D/UPD
system program; samples were loaded in a matrix solution (3-
nitrobenzyl alcohol) onto a stainless steel probe and bombarded
with Xenon atoms with an energy of 3 keV. During the HR FAB-
MS measurements a resolving power of 10 000 (10% valley
definition) was used. IR spectra were recorded on a Mattson-6030
Galaxy FT-IR spectrophotometer. Melting points were measured
on samples in unsealed capillaries and are uncorrected. Elemental
analyses were performed at the Microanalytical Laboratory of the
Laboratorium fu¨r Organische Chemie, ETH Zu¨rich, Switzerland.
(Diphenylphosphinoyl)acetylene (3a).21a Me3SiCt CMgBr (0.5
M in THF; 70 mL, 35 mmol) was added slowly at 0 °C to a solution
of Ph2P(O)Cl (8.28 g, 35 mmol) in THF (50 mL). The reaction
mixture was stirred for 0.5 h at 0 °C and subsequently for 1 h at
room temperature. Evaporation of the solvent and filtration over
silica gel with ethyl acetate as eluent gave pure Ph2P(O)Ct
Figure 2. Displacement ellipsoid plot of 7 drawn at the 50%
probability level. Hydrogen atoms and cocrystallized THF are
omitted for clarity. Selected bond lengths (Å) and angles (deg):
W1-P1 ) 2.4829(10), W1-C1 ) 2.003(4), W1-C3 ) 2.059(4),
P1-C11 ) 1.810(4), C1-O1 ) 1.147(5), C3-O3 ) 1.138(4),
C11-C21 ) 1.372(5), C11-N31 ) 1.351(4), C21-N11 )
1.338(5), N11-N21 ) 1.342(4), N21-N31 ) 1.304(4), C31-N11
) 1.442(5); P1-W1-C1 ) 174.79(12), W1-P1-C11 ) 115.80(12),
C11-P1-C12 ) 101.74(16).
21a
CSiMe3 (9.55 g, 91%) as a light brown solid. Removal of the
silyl group was established by dissolving Ph2P(O)Ct CSiMe3 in
THF (150 mL), H2O (0.5 mL) was added, and the reaction mixture
was cooled to -78 °C. TBAF on silica (500 mg, 1-1.5 mmol of
fluoride/g) was added, the reaction mixture was then slowly warmed
to room temperature, and additional H2O (1 mL) was added.
Volatiles were evaporated and the crude product was purified by
column chromatography over silica gel with ethyl acetate/hexane
(1:1) as eluent, affording 3a21a as a colorless solid (6.50 g, 81%).
Mp: 55-56 °C. 1H NMR (250.1 MHz, CDCl3): δ 3.32 (d, 3J(H,P)
) 9.7 Hz, 1H; t CH), 7.46-7.54 (m, 6H; PhH), 7.80-7.89 (m,
4H; Ph); 13C{1H} NMR (62.9 MHz, CDCl3): δ 79.0 (d, 1J(C,P) )
160.2 Hz; PCt ), 95.8 (d, 2J(C,P) ) 27.7 Hz; t CH), 128.9 (d,
Figure 3. Displacement ellipsoid plot of 8 drawn at the 50%
probability level. Hydrogen atoms and cocrystallized THF are
omitted for clarity. Selected bond lengths (Å) and angles (deg):
W1-P1 ) 2.4760(8), W1-C1 ) 2.012(3), W1-C3 ) 2.049(3),
Mo1-C6 ) 1.951(4), Mo1-N31 ) 2.277(3), P1-C11 ) 1.810(3),
C1-O1 ) 1.149(4), C3-O3 ) 1.134(4), C6-O6 ) 1.168(4),
C11-C21 ) 1.368(4), C11-N31 ) 1.376(4), C21-N11 )
1.340(4), N11-N21 ) 1.362(4), N21-N31 ) 1.319(4), C31-N11
) 1.434(4); P1-W1-C1 ) 173.90(10), W1-P1-C11 ) 120.48(10),
C11-P1-C12 ) 98.91(14), N11-C21-C11 ) 105.5(3), N21-
N11-C21 ) 111.5(3), N11-N21-N31 ) 105.8(2), N21-N31-C11
) 109.8(2).
2
3J(C,P) ) 13.6 Hz; m-Ph), 131.1 (d, J(C,P) ) 11.3 Hz; o-Ph),
(17) Multimetallic Catalysts in Organic Synthesis; Shibasaki, M.,
Yamamoto, Y., Eds.; Wiley-VCH: Weinheim, Germany, 2004.
(18) Cwiklicki, A.; Rehse, K. Arch. Pharm. Pharm. Med. Chem. 2004,
337, 156–163.
(19) Cotton, F. A.; McCleverty, J. A.; White, J. E. Inorg. Synth. 1990,
28, 45–47.
(20) Marinetti, A.; Bauer, S.; Ricard, L.; Mathey, F. Organometallics
1990, 9, 793–798.
(21) (a) Corriu, R. J. P.; Gue´rin, C.; Henner, B. J. L.; Jolivet, A. J.
Organomet. Chem. 1997, 530, 39–48. (b) Naaktgeboren, A.; Meijer, J.;
Vermeer, P.; Brandsma, L. Recl. TraV. Chim. Pays-Bas 1975, 94, 92–94.
(c) van Assema, S. G. A.; de Jong, G. B.; Ehlers, A. W.; de Kanter, F. J. J.;
Schakel, M.; Spek, A. L.; Lutz, M.; Lammertsma, K. Eur. J. Org. Chem.
2007, 2405–2412. (d) Rosenberg, D.; Drenth, W. Tetrahedron 1971, 27,
3893–3907.
Conclusions
In summary, a new phospha-based scorpionate has been
designed with three 1,2,3-triazole rings that is conveniently
synthesized by the click reaction between phenyl azide and
tris(ethynyl)phosphine oxide. Transition-metal coordination oc-

Phospha-Scorpionate Complexes by Click Chemistry
Organometallics, Vol. 27, No. 13, 2008 3213
1
4
132.4 (d, J(C,P) ) 122.0 Hz; ipso-Ph), 132.8 (d, J(C,P) ) 3.0
Hz; p-Ph). 31P{1H} NMR (101.3 MHz, CDCl3): δ 9.5 (s). HR EI-
MS: calcd for C14H11OP 226.0548, found 226.0541; m/z (%) 226
(100) [M]+.
purified by column chromatography over silica gel with ethyl acetate
as eluent, affording 3d21d (133 mg, 55%) as a pale white solid,
which was stored at -30 °C to avoid decomposition. Mp: 111-112
1
3
°C. H NMR (250.1 MHz, C6D6): δ 2.15 (d, J(H,P) ) 12.3 Hz;
(Diethynylphosphinoyl)benzene (3b).21b Me3SiCt CMgBr (∼0.4
M in THF; 30 mmol) was added dropwise at 0 °C to a solution of
PhP(O)Cl2 (2.61 g, 15 mmol) in THF (50 mL); subsequently the
reaction mixture was slowly warmed to room temperature, after
which 31P NMR showed complete conversion to the product. After
evaporation of the solvent, the remaining dark brown oil was
dissolved in diethyl ether (400 mL) and extracted with H2O (2 ×
200 mL), dried over MgSO4, and evaporated under reduced
pressure. The crude product was then dissolved in THF (50 mL)
and 0.5 mL of H2O was added, after which TBAF on silica (500
mg, 1-1.5 mol % of fluoride/g) was added at 0 °C. The reaction
mixture was slowly warmed to room temperature and stirred for
another 1 h. Volatiles were evaporated, and the crude product was
purified by column chromatography over silica gel with ethyl
acetate/hexane (1:1) as eluent, affording 3b21b as a brownish solid
t CH). 13C{1H} NMR (62.9 MHz, C6D6): δ 78.8 (d, J(C,P) )
1
228.5 Hz; PCt ), 91.8 (d, 2J(C,P) ) 44.2 Hz; t CH). 31P{1H} NMR
(101.3 MHz, C6D6): δ -56.8 (s). IR (CH2Cl2): ν 3280 (m, C-H),
2068 (s, Ct C), 1235 cm-1 (m, PdO). HR EI-MS: calcd for
C6H3OP 121.9922, found 121.9916; m/z (%) 122 (6) [M]+.
4-(Diphenylphosphinoyl)-1-phenyl-1H-1,2,3-triazole (4a). So-
dium ascorbate (0.10 mmol, 100 µL of a freshly prepared 1 M
solution in H2O), followed by CuIISO4 · 5H2O (3.0 mg, 0.01 mmol),
dissolved in H2O (50 µL), were added to a suspension of 3a (226
mg, 1.00 mmol) and phenyl azide (119 mg, 1.00 mmol) in a 1:1
mixture of H2O and tBuOH (4 mL). The reaction mixture was stirred
for 16 h, during which time a light yellow solid precipitated. The
reaction mixture was extracted with DCM (2 × 10 mL) and dried
over MgSO4, volatiles were evaporated, and the crude product was
purified by column chromatography over silica gel with ethyl
acetate/hexane (1:1) as eluent, followed by 1% ethanol in ethyl
acetate, affording 4a as a colorless solid (248 mg, 72%). Mp:
191-192 °C. 1H NMR (250.1 MHz, CDCl3): δ 7.49-7.55 (m, 9H;
m-PhH, p-PhH), 7.74 (d, 3J(H,H) ) 7.1 Hz, 2H; o-PhH-N),
7.90-7.99 (m, 4H; o-PhH-P), 8.63 (s, 1H; dCH). 13C{1H} NMR
(62.9 MHz, CDCl3): δ 121.0 (s; o-Ph-N), 128.8 (d; 3J(C,P) ) 12.8
Hz; m-Ph-P), 129.6 (s; p-Ph-N), 130.2 (s; m-Ph-N), 131.8 (d;
2J(C,P) ) 9.7 Hz; o-Ph-P), 132.5 (s; p-Ph-P), 129.3 (d; 2J(C,P) )
23.5 Hz; PCdCH), 132.5 (d, 1J(C,P) ) 110.5 Hz; ipso-Ph-P), 136.7
1
(1.42 g, 54%). Mp: 83-84 °C. H NMR (250.1 MHz, CDCl3): δ
3.40 (d, 3J(H,P) ) 11.0 Hz, 2H; t CH), 7.45-7.52 (m, 3H; PhH),
7.82-7.92 (m, 2H; PhH). 13C{1H} NMR (62.9 MHz, CDCl3): δ
1
2
78.7 (d, J(C,P) ) 194.2 Hz; PCt ), 93.9 (d, J(C,P) ) 35.9 Hz;
3
2
t CH), 129.4 (d, J(C,P) ) 15.3 Hz; m-Ph), 130.8 (d, J(C,P) )
12.8 Hz; o-Ph), 131.4 (d, 1J(C,P) ) 142.6 Hz; ipso-Ph), 133.8 (d,
4J(C,P) ) 3.1 Hz; p-Ph). 31P{1H} NMR (101.3 MHz, CDCl3): δ
-19.5 (s). IR (CH2Cl2): ν 3287 (m, C-H), 2061 (s, Ct C), 1207
cm-1 (s; PdO). HR EI-MS: calcd for C10H7OP 174.0234, found
174.0225; m/z (%) 174 (100) [M]+.
1
(s; ipso-Ph-N), 143.1 (d, J(C,P) ) 143.2 Hz; PCdCH). 31P{1H}
(Diisopropylamino)diethynylphosphine Oxide (3c).21c Me3SiCt
CMgBr (2 equiv, ∼0.4 M in THF) was added dropwise at 0 °C to
NMR (101.3 MHz, CDCl3): δ 17.4 (s). HR FAB-MS: calcd for
C20H17N3OP (M + H) 346.1109, found 346.1110; m/z (%) 346 (100)
[M]+.
i
a solution of Pr2NP(O)Br2 (950 mg, 3.1 mmol) in THF (10 mL),
and the reaction mixture was slowly warmed to room temperature;
the 31P NMR spectrum showed complete conversion to the product.
The light brown residual oil, obtained after solvent evaporation,
was dissolved in diethyl ether (400 mL), washed with H2O, and
dried over MgSO4. The crude product was dissolved in wet THF
(50 mL), and TBAF on silica (250 mg, 1-1.5 mol % of fluoride/g)
was added at 0 °C. The reaction mixture was stirred for 1 h and
quenched with H2O. Volatiles were evaporated, and the crude
product was purified by column chromatography over silica gel
with ethyl acetate/hexane (1:1) as eluent, affording 3c21c as a light
4-(Diphenylphosphanyl)-1-phenyl-1H-1,2,3-triazole (2a). A mix-
ture of 4a (345 mg, 1.00 mmol) and PhSiH3 (875 mg, 8.1 mmol)
was heated at 100 °C for 12 h. After evaporation of excess PhSiH3,
the remaining white solid was dissolved in diethyl ether and filtered
over a short path of silica gel. Solvents were evaporated, and the
residue was extracted into hexane, affording, after evaporation of
all volatiles, 2a as a colorless solid (310 mg, 94%). Mp: 119-120
1
°C. H NMR (250.1 MHz, CDCl3): δ 7.34-7.68 (m, 13H; PhH),
7.68 (m, 2H; o-PhH-N), 7.81 (s, 1H; dCH). 13C{1H} NMR (62.9
2
MHz, CDCl3): δ 120.9 (s; o-Ph-N), 127.5 (d, J(C,P) ) 24.0 Hz;
1
yellow solid (415 mg, 68%). Mp: 134-135 °C. H NMR (250.1
PC)CH), 128.8 (d, 3J(C,P) ) 7.3 Hz; m-Ph-P), 129.0 (s; p-Ph-N),
3
MHz, CDCl3): δ 1.31 (d, J(H,H) ) 6.8 Hz, 12H; CH3), 3.05 (d,
129.4 (s; m-Ph-N), 130.0 (s; p-Ph-P), 133.9 (d, 2J(C,P) ) 20.0 Hz;
3J(H,P) ) 11.6 Hz, 2H; ‘CH), 3.60-3.74 (m, 3J(H,P) ) 21.2 Hz,
3J(H,H) ) 6.8 Hz, 2H; NCH). 13C{1H} NMR (62.9 MHz, CDCl3):
δ 22.5 (d, 3J(C,P) ) 2.1 Hz; CH3), 46.9 (d, 2J(C,P) ) 6.9 Hz;
NCH), 81.1 (d, 1J(C,P) ) 224.7 Hz; PCt ), 88.3 (d, 2J(C,P) )
41.5 Hz; t CH). 31P{1H} NMR (101.3 MHz, CDCl3): δ -21.4 (s).
IR (CH2Cl2): ν 3285 (m, C-H), 2063 (m, Ct C), 1238 cm-1 (m,
PdO);. HR EI-MS: calcd for C10H16NOP 197.0970, found 197.0969;
m/z (%) 197 (8) [M]+.
o-Ph-P), 136.3 (d, J(C,P) ) 6.6 Hz; ipso-Ph-P), 137.1 (s; ipso-
1
Ph-N), 145.9 (d, 1J(C,P) ) 6.7 Hz; PCdCH). 31P{1H} NMR (101.3
MHz, CDCl3): δ -32.4 (s). HR FAB-MS: calcd for C20H17N3P (M
+ H) 330.1160, found 330.1163; m/z (%) 330 (100) [M]+.
(Bis(1-phenyl-1H-1,2,3-triazol-4-yl)phosphinoyl)benzene (4b). So-
dium ascorbate (0.3 mmol, 0.3 mL of a freshly prepared 1 M
solution in H2O), followed by CuIISO4 · 5H2O (15 mg, 0.06 mmol),
dissolved in H2O (100 µL), were added to a suspension of 3b (509
mg, 2.93 mmol) and phenyl azide (700 mg, 5.88 mmol) in a 1:1
Tris(ethynyl)phosphine Oxide(3d).21d A freshly prepared so-
lution of Me3SiCt CMgBr (∼0.3 M in THF) was added dropwise
at 0 °C to a solution of P(O)Cl3 (307 mg, 2.00 mmol) in THF (10
mL) until 31P NMR showed complete conversion of the starting
material. The remaining acetylenic Grignard reagent was quenched
with H2O. The dark brown reaction mixture was warmed to room
temperature, and the solvent was evaporated under reduced pressure.
H2O (50 mL) was added, and extraction with diethyl ether (2 × 50
mL) gave a dark brown oil, which was purified by filtration over
silica gel with ethyl acetate as eluent. The 31P NMR spectrum
showed the formation of several triethynylphosphine oxides result-
ing from partial desilylation. Dissolving the dark brown oil in THF/
H2O (20 mL/0.25 mL) with TBAF on silica (250 mg, 1-1.5 mol
% of fluoride/g) and stirring the solution for 1 h resulted in complete
desilylation. Volatiles were evaporated, and the crude product was
t
mixture of H2O and BuOH (12 mL). The reaction mixture was
stirred for 16 h, during which time a light yellow solid precipitated.
The reaction mixture was extracted with DCM and dried over
MgSO4, volatiles were evaporated, and the crude product was
purified by column chromatography over silica gel with ethyl
acetate/hexane (1:1) as eluent, followed by 1% ethanol in ethyl
acetate, affording 4b as a colorless solid (890 mg, 74%). Mp:
179-180 °C. 1H NMR (250.1 MHz, CDCl3): δ 7.43-7.56 (m, 9H;
m-PhH, p-PhH), 7.73 (d, 3J(H,H) ) 7.1 Hz, 4H; o-PhH-N),
8.10-8.19 (m, 2H; o-PhH-P), 8.57 (s, 2H; dCH). 13C{1H} NMR
(62.9 MHz, CDCl3): δ 121.2 (s; o-Ph-N), 129.0 (d, 2J(C,P) ) 26.5
Hz; PC)CH), 129.0 (d, 3J(C,P) ) 13.4 Hz; m-Ph-P), 129.8 (s; p-Ph-
N), 130.2 (s; m-Ph-N), 131.8 (d, 2J(C,P) ) 10.6 Hz; o-Ph-P), 133.1
1
(s; p-Ph-P), 136.6 (s; ipso-Ph-N), 142.7 (d, J(C,P) ) 144.8 Hz;

3214 Organometallics, Vol. 27, No. 13, 2008
Van Assema et al.
PCdCH), ipso-Ph-P could not be resolved. 31P{1H} NMR (101.3
MHz, CDCl3): δ 5.3 (s). HR FAB-MS: calcd for C22H18N6OP (M
+ H) 413.1280, found 413.1280; m/z (%) 413 (100) [M]+.
for 3 h. An orange solid precipitated immediately, which was filtered
off and dried in vacuo to afford 6 (0.26 g, 65%). Orange needles,
suitable crystals for X-ray crystallography, were obtained by slowly
diffusing ethanol into a saturated solution of 6 in DMSO. Mp:
271-272 °C dec. 1H NMR (250.1 MHz, DMSO-d6): δ 7.56-7.71
(m, 9H; m-PhH, p-PhH), 7.90 (m, 6H; o-PhH), 10.00 (s, 3H; dCH).
13C{1H} NMR (62.9 MHz, DMSO-d6): δ 121.4 (s; o-Ph), 130.1
(s; m-Ph), 130.6 (s; p-Ph) 131.1 (s; PC)CH), 135.4 (d, 1J(C,P) )
149.8 Hz; PCdCH), 135.5 (s; ipso-Ph). 31P{1H} NMR (101.3 MHz,
DMSO-d6): δ -9.7 (s). HR FAB-MS: C24H19N9Cl3OPRh (M +
H) calcd 687.9571, found 687.9565; m/z (%) 688 (5) [M]+, 652
(46) [M - H - Cl]+.
Bis(1-phenyl-1H-1,2,3-triazol-4-yl)(diisopropylamino)phos-
phine Oxide (4c). Sodium ascorbate (0.60 mmol, 600 µL of a freshly
prepared 1 M solution in H2O), followed by CuIISO4 · 5H2O (15.0
mg, 0.06 mmol), dissolved in H2O (100 µL), were added to a
suspension of 3c (600 mg, 3.07 mmol) and phenyl azide (730 mg,
t
6.14 mmol) in a 1:1 mixture of H2O and BuOH (12 mL). The
reaction mixture was stirred for 16 h, during which time a light
brown solid precipitated. After filtration, volatiles were evaporated
and the crude product was purified by column chromatography over
silica gel with ethyl acetate/ethanol (95:5) as eluent, affording 4c
as a light yellow solid (0.97 g, 72%). Mp: 231-232 °C. 1H NMR
(250.1 MHz, CDCl3): δ 1.34 (d, 3J(H,H) ) 6.7 Hz, 12H;
CH(CH3)2), 3.69-3.82 (m, 2H; CH(CH3)2), 7.43-7.57 (m, 6H;
m-PhH, p-PhH), 7.75-7.80 (m, 4H; o-PhH), 8.48 (s, 2H; dCH).
(PhN3C2H)3PW(CO)5 (7). 5 (690 mg, 1.49 mmol) was added to
a solution of freshly prepared W(CO)5(MeCN)20 (700 mg, 1.91
mmol) in dry THF (30 mL), and the yellow solution was stirred
for 16 h at room temperature. The volatiles were evaporated,
and the remaining dark yellow foam was purified by column
chromatography over silica gel with DCM as eluent, followed
by ethyl acetate/hexane (1:1), affording 7 as a light yellow
crystalline solid (1.01 g, 86%). Suitable crystals for X-ray
crystallography were obtained from THF/hexane at -20 °C. Mp:
3
13C{1H} NMR (62.9 MHz, CDCl3): δ 23.1 (d, J(C,P) ) 1.8 Hz;
CH(CH3)2), 47.0 (d, 2J(C,P) ) 5.9 Hz; CH(CH3)2), 121.0 (s; o-Ph),
2
128.3 (d, J(C,P) ) 28.6 Hz; PCdCH), 129.5 (s; p-Ph), 130.2 (s;
m-Ph), 136.8 (s; ipso-Ph), 144.9 (d, 1J(C,P) ) 167.9 Hz; PCdCH).
31P{1H} NMR (101.3 MHz, CDCl3): δ 7.8 (s). HR FAB-MS: calcd
for C22H27N7OP (M + H) 436.2015, found 436.2027; m/z (%) 436
(100) [M]+.
1
211-212 °C dec. H NMR (250.1 MHz, CDCl3): δ 7.43-7.56
(m, 9H; m-PhH, p-PhH), 7.73-7.77 (m, 6H; o-PhH), 8.55 (s,
3H; dCH). 1H NMR (250.1 MHz, CD2Cl2): δ 7.44-7.64 (m,
9H; m-PhH, p-PhH), 7.71-7.85 (m, 6H; o-PhH), 8.53 (s, 3H;
dCH). 13C{1H} NMR (62.9 MHz, CDCl3): δ 121.1 (s; o-Ph),
Tris(1-phenyl-1H-1,2,3-triazol-4-yl)phosphine Oxide (4d). So-
dium ascorbate (0.2 mmol, 200 µL of a freshly prepared 1 M
solution in H2O), followed by CuIISO4 · 5H2O (8 mg, 0.03 mmol),
dissolved in H2O (50 µL), were added to a suspension of 3d (139
mg, 1.14 mmol) and phenyl azide (417 mg, 3.51 mmol) in a 1:1
mixture of H2O and tBuOH (4 mL). The reaction mixture was stirred
for 18 h, during which time a brown solid precipitated. Fifteen
milliliters of H2O and 2 mL of saturated aqueous NH4Cl were
added, and the mixture was extracted with DCM (3 × 10 mL).
The combined organic layers were dried over MgSO4, and all solids
were removed by filtration over Celite. The Celite plug was washed
with DCM (3 × 8 mL), and all volatiles were thoroughly evaporated
2
127.6 (d, J(C,P) ) 24.0 Hz; PCdCH), 129.8 (s; p-Ph), 130.2
(s; m-Ph), 136.7 (s; ipso-Ph), 142.8 (d, 1J(C,P) ) 73.7 Hz;
2
2
PCdCH), 196.4 (d, J(C,P) ) 7.1 Hz; COeq), 198.8 (d, J(C,P)
) 24.8 Hz; COax). 13C{1H} NMR (62.9 MHz, CD2Cl2): δ 121.2
(s, o-Ph), 127.8 (d, 2J(C,P) ) 23.4 Hz; PC)CH), 129.8 (s, p-Ph),
130.3 (s, m-Ph), 136.9 (s, ipso-Ph), 142.9 (d, 1J(C,P) ) 74.4
Hz; PCdCH), 196.7 (d, 2J(C,P) ) 7.2 Hz; COeq), 199.1 (d,
2J(C,P) ) 24.6 Hz; COax). 31P{1H} NMR (101.3 MHz, CDCl3):
1
δ -42.3 (s, J(P,W) ) 257.8 Hz). 31P{1H} NMR (101.3 MHz,
1
CD2Cl2): δ -40.6 (s, J(P,W) ) 257.2 Hz). IR (KBr): ν 2075
(m, COax), 1921 cm-1 (s, COeq). HR FAB-MS: calcd for
C29H19N9O5PW (M + H) 788.0756, found 788.0776; m/z (%)
788 (15) [M]+, 731 (34) [M - H - 2CO]+.
t
from the clear yellow filtrates. To remove residual BuOH, the
resulting pale foam was redissolved in 12 mL of DCM and again
taken to dryness, affording 4d as a light yellow solid still containing
0.39 equiv of DCM (465 mg, 80%). 4d · 0.5DCM can be obtained
as pale crystals from DCM/pentane at -20 °C. Mp: 201-202 °C.
1H NMR (250.1 MHz, CDCl3): δ 5.29 (s; DCM), 7.48-7.58 (m,
9H; m-PhH, p-PhH), 7.77 (d, 3J(H,H) ) 6.9 Hz, 6H; o-PhH), 8.87
(s, 3H; dCH). 13C{1H} NMR (62.9 MHz, CDCl3): δ 53.5 (s,
(OC)5WP(C2HN3Ph)3Mo(CO)3 (8). 7 (98.1 mg, 0.125 mmol) and
19
(C7H8)Mo(CO)3 (33.9 mg, 0.125 mmol) were taken up in THF
(8 mL), with stirring. The resulting bright red solution turned deep
red within 10 min, after which the reaction mixture was left standing
overnight in the dark at ambient temperature. Subsequently, the
glass wall of the reaction vessel was scratched to initiate crystal-
lization, and 1 h later red needles had formed, which were separated
from the mother liquor and dried in a stream of N2 to afford 8,
which still contained 1.58 equiv of THF according to 1H NMR
integration (100.6 mg, 74%). The compound slowly decomposes
both in the solid state and in solution upon exposure to air but is
a stable solid for weeks when stored under N2 at ambient
temperature in the dark. Crystals suitable for X-ray structure
determination were obtained by mixing 7 (51.1 mg, 0.065 mmol)
and (C7H8)Mo(CO)3 (17.7 mg, 0.065 mmol) in THF (5 mL). Mp
2
DCM), 121.1 (s; o-Ph), 129.6 (s; p-Ph), 129.6 (d, J(C,P) ) 28.6
Hz; PCdCH), 130.0 (s; m-Ph), 136.4 (s; ipso-Ph), 141.0 (d, 1J(C,P)
) 157.1 Hz; PCdCH). 31P{1H} NMR (101.3 MHz, CDCl3): δ -5.7
(s). HR FAB-MS: calcd for C24H19N9OP (M + H) 480.1450, found
480.1447; m/z (%) 480 (100) [M]+. Anal. Calcd for C24.5H19ClN9OP
(4d + 0.5 equiv of DCM): C, 56.38; H, 3.67; N, 24.15. Found: C,
56.44; H, 3.82; N, 24.26.
Tris(1-phenyl-1H-1,2,3-triazol-4-yl)phosphane (5). A mixture of
4d (500 mg, 1.04 mmol) and PhSiH3 (875 mg, 8.1 mmol) was
heated at 100 °C for 48 h. After evaporation of excess PhSiH3, the
remaining white solid was washed with hexanes, affording, after
drying in vacuo, 5 as an air-sensitive off-white solid (430 mg, 90%).
Mp: 197-198 °C dec. 1H NMR (250.1 MHz, CDCl3): δ 7.43-7.54
(m, 9H; m-PhH, p-PhH), 7.72-7.76 (m, 6H; o-PhH), 8.42 (s, 3H;
dCH). 13C{1H} NMR (62.9 MHz, CDCl3): δ 121.0 (s; o-Ph), 128.1
(d, 2J(C,P) ) 23.5 Hz; PCdCH), 129.3 (s; p-Ph), 130.1 (s; m-Ph),
137.0 (s; ipso-Ph), 142.7 (d, 1J(C,P) ) 4.5 Hz; PCdCH). 31P{1H}
NMR (101.3 MHz, CDCl3): δ -83.7 (s). HR-FAB-MS: calcd for
C24H19N9P (M + H) 464.1501, found 464.1507; m/z (%) 464 (72)
[M]+.
1
(sealed capillary): 224 °C dec. H NMR (250.1 MHz, CD2Cl2): δ
1.82 (m; THF), 3.68 (m; THF), 7.54-7.67 (m, 9H; m-PhH, p-PhH),
7.71-7.81 (m, 6H; o-PhH), 8.59 (s, 3H; dCH). 13C{1H} NMR
(100.6 MHz, CD2Cl2): δ 25.9 (s; THF), 68.1 (s; THF), 121.9 (s;
2
o-Ph), 130.0 (d, J(C,P) ) 41.1 Hz; PCdCH), 130.6 (s; m-Ph),
1
131.6 (s; p-Ph), 135.9 (s; ipso-Ph), 139.3 (d, J(C,P) ) 65.5 Hz;
PCdCH), 194.6 (d, 2J(C,P) ) 25.5 Hz; W-COax), 195.7 (d, 2J(C,P)
) 6.4 Hz; W-COeq), 227.8 (s; Mo-CO). 31P{1H} NMR (101.3 MHz,
1
CD2Cl2): δ -62.8 (s, J(P,W) ) 261.1 Hz). IR (KBr): ν 2083 (s,
W-COax), 1999 (sh, W-CO), 1954 (vs, W/Mo-CO), 1907 (vs,
W/Mo-CO), 1794 (vs, Mo-CO), 1765 cm-1 (vs, Mo-CO). HR FAB-
MS: calcd for C32H1896MoN9O8P184W 966.9581, found 966.9576;
m/z (%) 969 (73) [M]+, 731 (32) [M - Mo(CO)3 - 2 CO]+. Anal.
(K3-OP(C2HN3Ph)3)RhCl3 (6). RhCl3 · xH2O (135 mg, 0.6 mmol)
was added to a solution of 4d (280 mg, 0.58 mmol) in THF/EtOH
(1 mL/20 mL), and the reaction mixture was stirred under reflux

Phospha-Scorpionate Complexes by Click Chemistry
Organometallics, Vol. 27, No. 13, 2008 3215
Calcd for C38H30MoN9O9.5PW (8 + 1.5 equiv of THF): C, 42.44;
H, 2.81; N, 11.72. Found: C, 41.87; H, 2.87; N, 11.75.
15), a ) 27.6093(5) Å, b ) 20.4105(5) Å, c ) 13.53985(18) Å, ꢀ
) 114.452(1)°, V ) 6945.6(2) Å3, Z ) 8, Dx ) 1.644 g/cm3, µ )
3.43 mm-1. A total of 78 673 reflections were measured up to a
resolution of ((sin θ)/λ)max ) 0.65 Å-1 at a temperature of 150 K.
An absorption correction based on multiple measured reflections
was applied (0.56-0.81 correction range). A total of 7986 reflec-
tions were unique (Rint ) 0.0771). A total of 451 parameters were
refined with no restraints. R1/wR2 (I > 2σ(I)): 0.0331/0.0576. R1/
wR2 (all reflections): 0.0623/0.0651. S ) 1.031. The residual
electron density was between -0.89 and 1.08 e/Å3.
Crystal Structure Determinations. X-ray intensities were
measured on a Nonius Kappa CCD diffractometer with a rotating
anode (graphite monochromator, λ ) 0.710 73 Å). The structures
were solved with automated Patterson methods22 and refined with
SHELXL-9723 against F2 of all reflections. Non-hydrogen atoms
were refined with anisotropic displacement parameters. All hydro-
gen atoms were introduced in geometrically idealized positions and
refined with a riding model. Geometry calculations and checking
for higher symmetry was performed with the PLATON program.24
Crystallographic data have been deposited with the Cambridge
Crystallographic Data Centre as Supplementary Publication Nos.
CCDC 639631 (6), 639632 (7), and 639633 (8). These data can be
obtained free of charge from the Cambridge Crystallographic Data
Centre via www.ccdc.cam.ac.uk/data_request/cif.
Data for compound 8: C32H18MoN9O8PW · C4H8O + disordered
solvent, fw ) 1039.4,25 red plate, 0.30 × 0.18 × 0.06 mm3,
monoclinic, P21/c (No. 14), a ) 10.87209(6) Å, b ) 17.3152(2)
Å, c ) 29.6070(6) Å, ꢀ ) 98.052(1)°, V ) 5518.65(14) Å3, Z )
4, Dx ) 1.251 g/cm3,25 µ ) 2.39 mm-1 25
.
A total of 103 081
reflections were measured up to a resolution of ((sin θ)/λ)max
)
Data for compound 6: C24H18Cl3N9OPRh + disordered solvent,
fw ) 688.70,25 yellow needle, 0.12 × 0.03 × 0.03 mm3,
monoclinic, P21/c (No. 14), a ) 9.3892(2) Å, b ) 16.7894(5) Å,
c ) 21.7055(7) Å, ꢀ ) 109.1762(10)°, V ) 3231.78(16) Å3, Z )
0.65 Å-1 at a temperature of 150 K. An absorption correction based
on multiple measured reflections was applied (0.18-0.43 correction
range). A total of 12 685 reflections were unique (Rint ) 0.0567).
The crystal structure contains large voids (2136 Å3/unit cell) filled
with disordered solvent molecules. Their contribution to the
structure factors was secured by back-Fourier transformation using
the SQUEEZE routine of the PLATON program,24 resulting in 440
electrons/unit cell. A total of 514 parameters were refined with no
restraints. R1/wR2 (I > 2σ(I)): 0.0313/0.0747. R1/wR2 (all
reflections): 0.0410/0.0773. S ) 1.086. The residual electron density
was between -0.94 and 1.39 e/Å3.
4, Dx ) 1.415 g/cm3,25 µ ) 0.86 mm-1 25
.
A total of 22 074
reflections were measured up to a resolution of ((sin θ)/λ)max
)
0.53 Å-1 at a temperature of 125 K. An absorption correction was
not considered necessary. A total of 3940 reflections were unique
(Rint ) 0.0614). The crystal structure contains large voids (754.5
Å3/unit cell) filled with disordered solvent molecules. Their
contribution to the structure factors was secured by back-Fourier
transformation using the SQUEEZE routine of the PLATON
program,24 resulting in 197 electrons/unit cell. A total of 352
parameters were refined with no restraints. R1/wR2 (I > 2σ(I)):
0.0375/0.0899. R1/wR2 (all reflections): 0.0529/0.0942. S ) 1.013.
The residual electron density was between -0.55 and 0.60 e/Å3.
Data for compound 7: C29H18N9O5PW · C4H8O, fw ) 859.45,
yellow needle, 0.18 × 0.09 × 0.06 mm3, monoclinic, C2/c (No.
Acknowledgment. This work was partially supported by
the Council for Chemical Sciences of The Netherlands
Organization for Scientific Research (NWO/CW). We thank
Dr. M. Smoluch (EI) of our department and J. W. H. Peeters
of the University of Amsterdam (FAB) for recording the
high-resolution mass spectra.
(22) Beurskens, P. T.; Admiraal, G.; Beurskens, G.; Bosman, W. P.;
Garcia-Granda, S.; Gould, R. O.; Smits, J. M. M.; Smykalla, C. (1999)
The DIRDIF99 Program System, Technical Report of the Crystallography
Laboratory; University of Nijmegen, Nijmegen, The Netherlands.
(23) Sheldrick, G. M. SHELXL-97 Program for Crystal Structure
Refinement; University of Go¨ttingen, Go¨ttingen, Germany, 1997.
(24) Spek, A. L. J. Appl. Crystallogr. 2003, 36, 7–13.
Supporting Information Available: Figures giving the NMR
spectra of all new compounds and CIF files giving crystallographic
data for 6-8. This material is available free of charge via the
Internet at http://pubs.acs.org.
(25) Derived values do not contain the contribution of the disordered
solvent molecules.
OM800127H