The first examples of isonitrile insertion into a phosphido bridge and the crystal and molecular structures of [Pt2(PBut2){/i,?;2-P(But2)C(=NAr)}(CNAr)2] and [Pt{//,i/2-P(But2)C(NHAr)}(CNAr)]2(CF3SO3)2 (Ar = p-Tolyl)

Article abstract of DOI:10.1021/om000461t

The platinum(I) dinuclear carbonyl [Pfefa-PBuMPBuHXCO)] (1) reacts with organic isonitriles RNC (R =p-tolyl, Bu*, PhCH2), yielding the mono- and disubstituted derivatives [Pt2(/(-PBut2)2(PBut2H)(CNR)] (2, R = p-tolyl; 3, R = Bu1; 4, R = PhCH2) and [PtPBu)(CNR)]2 (5, R = p-tolyl; 6, R = Bu1; 7, R = PhCH2). Only with the aromatic isonitrile does the reaction proceed through two further well-separated steps, giving [PtPBuyi/*,?/2P(But2)C(=NAr)}(CNAr)2] (8) and [Pt{/iJ?/2-P(But2)C(=NAr)}(CNAr)]2 (9). These arise from the unprecedented reversible isonitrile insertion into the M-P bonds of the phosphidobridges. When 8 or 9 are reacted with CFaSOaH, the cyclic carbenes [Pt2(/i-PBut2){/fJ7/2P(BuyCCNHAr)}(CNAr)2]CF3SO3 (10) and [Pt(//,r/2-P(But2)C(NHAr)}(CNAr)]2 (CF3SO3)2 (11) are respectively formed. The crystal and molecular structures of complexes 8 and 11 were solved by X-ray diffraction.

Full text of DOI:10.1021/om000461t

Organometallics 2000, 19, 4589-4595
4589
Th e F ir st Exa m p les of Ison itr ile In ser tion in to a
P h osp h id o Br id ge a n d th e Cr ysta l a n d Molecu la r
Str u ctu r es of [P t2(µ-P Bu t ){µ,η2-P (Bu t )C(dNAr )}(CNAr )2]
2
2
a n d [P t{µ,η2-P (Bu t )C(NHAr )}(CNAr )]2(CF 3SO3)2 (Ar )
2
p-Tolyl)
Serena Cristofani,† Piero Leoni,*,† Marco Pasquali,† Frank Eisentraeger,‡,§ and
Alberto Albinati‡
Dipartimento di Chimica e Chimica Industriale, Universita` di Pisa, I-56126 Pisa, Italy, and
Istituto di Chimica Farmaceutica, Viale Abruzzi 42, I-20131 Milano, Italy
Received J une 1, 2000
The platinum(I) dinuclear carbonyl [Pt2(µ-PBut )2(PBut H)(CO)] (1) reacts with organic
2
2
isonitriles RNC (R ) p-tolyl, But, PhCH2), yielding the mono- and disubstituted derivatives
[Pt2(µ-PBut )2(PBut H)(CNR)] (2, R ) p-tolyl; 3, R ) But; 4, R ) PhCH2) and [Pt(µ-PBut )-
2
2
2
(CNR)]2 (5, R ) p-tolyl; 6, R ) But; 7, R ) PhCH2). Only with the aromatic isonitrile does
the reaction proceed through two further well-separated steps, giving [Pt2(µ-PBut ){µ,η2-
2
P(But )C(dNAr)}(CNAr)2] (8) and [Pt{µ,η2-P(But )C(dNAr)}(CNAr)]2 (9). These arise from
2
2
the unprecedented reversible isonitrile insertion into the M-P bonds of the phosphido-
bridges. When 8 or 9 are reacted with CF3SO3H, the cyclic carbenes [Pt2(µ-PBut ){µ,η2-
2
P(But )C(NHAr)}(CNAr)2]CF3SO3 (10) and [Pt{µ,η2-P(But )C(NHAr)}(CNAr)]2 (CF3SO3)2 (11)
2
2
are respectively formed. The crystal and molecular structures of complexes 8 and 11 were
solved by X-ray diffraction.
In tr od u ction
and then denied.6e Moreover, palladium-catalyzed isoni-
trile insertions into Si-Si bonds were thought to proceed
via the insertion into Pd-Si bonds.7
Isonitrile ligands insert easily into various types of
metal-carbon bonds, yielding iminoacyl derivatives of
great interest in organometallic synthesis.1 Even though
these reactions are quite common, related insertions
into other metal-element bonds are by far less studied.
Some examples of insertion into M-H,2 M-O,3 or M-N4
bonds have been reported, but few cases are known with
the heavier main-group elements.
For example, only recently have the first insertions
into metal-sulfur or -selenium bonds been discussed5a,b
(examples of isonitrile insertion into Os-S bonds were
also suggested in previous reports),5c,d and the insertion
into M-X (Cl, Br) bonds has been first suggested6a-d
As far as the metal-phosphorus bonds are concerned,
we are only aware of a few recent data on the insertion
into the M-P bonds of a terminal phosphide bonded to
zirconium8 or uranium9 or of a phosphazirconacy-
clobutene.10 The related insertion of carbon monoxide
is also very rare, and the insertion into the M-P bonds
of Cp*HfCl2(PBut ), reported by Bercaw et al.,11 is still
2
the unique example (if one neglects the insertion of CO
and other ligands into the M-P bonds of phosphido-
bridged derivatives).12
(5) (a) Kuniyasu, H.; Sugoh, K.; Su, M. S.; Kurosawa, H. J . Am.
Chem. Soc. 1997, 119, 4669. (b) Kuniyasu, H.; Maruyama, A.; Kuro-
sawa, H. Organometallics 1998, 17, 908. (c) Grundy, K. R.; Roper, W.
R. J . Organomet. Chem. 1976, 113, C45. (d) Clark. G. R.; Collins, T.
J .; Hall, D.; J ames, S. M.; Roper, W. R. J . Organomet. Chem. 1977,
141, C5.
(6) (a) Behnam-Dahkordy, M.; Crociani, B.; Nicolini, M.; Richards,
R. L. J . Organomet. Chem. 1979, 181, 69. (b) Crociani, B.; Nicolini,
M.; Richards, R. L. J . Organomet. Chem. 1975, 101, C1. (c) Crociani,
B.; Richards, R. L. J . Chem. Soc., Chem. Commun. 1973, 127. (d)
Behnam-Dahkordy, M.; Crociani, B.; Richards, R. L. J . Chem. Soc.,
Dalton Trans. 1977, 2015. (e) Silverman, L. D.; Dewan, J . C.;
Giandomenico, C. M.; Lippard, S. J . Inorg. Chem. 1980, 19, 3379.
(7) Ito, Y.; Suginome, M.; Matsuura, T.; Murakami, M. J . Am. Chem.
Soc. 1991, 113, 8899.
(8) Lindenberg, F.; Sieler, J .; Hey-Hawkins, E. Polyhedron 1996,
15, 1459.
(9) Zanella, P.; Brianese, N.; Casellato, U.; Ossala, F.; Porchin, M.;
Rossetto, G.; Graziani, R. J . Chem. Soc., Dalton Trans. 1987, 2039.
(10) Breen, T. L.; Stephan, D. W. Organometallics 1996, 15, 5729.
(11) Roddick, D. M.; Santarsiero, B. D.; Bercaw, J . E. J . Am. Chem.
Soc. 1985, 107, 4670.
† Universita` di Pisa.
‡ Istituto di Chimica Farmaceutica.
§ Permanent address: Organisch-Chemisches Institut, Universita¨t
Heidelberg, Heidelberg, Germany.
(1) Singleton, E.; Oosthuizen, H. E. Adv. Organomet. Chem. 1983,
22, 209.
(2) (a) Tanase, T.; Ohizumi, T.; Kobayashi, K.; Yamamoto, Y.
Organometallics 1996, 15, 3404. (b) Christian, D. F.; Clark, H. C.;
Stepaniak, R. F. J . Organomet. Chem. 1976, 112, 209. (c) Hogarth, G.;
Lavender, M. H.; Shukri, K. Organometallics 1995, 14, 2325. (d) Clark,
J . R.; Fanwick, P. E.; Rothwell, I. P. Organometallics 1996, 15, 3232.
(e) Wolczanski, P. T.; Bercaw, J . E. J . Am. Chem. Soc. 1979, 101, 6450.
(3) Michelin, R. A.; Ros, R. J . Organomet. Chem. 1979, 169, C42.
(4) (a) Galakhov, M.; Gomez-Sal, P.; Martin, A.; Mena, M.; Yelamos,
C. Eur. J . Inorg. Chem. 1998, 1319. (b) Kim, Y. J .; Kim, D. H.; Lee, J .
Y.; Lee, S. W. J . Organomet. Chem. 1997, 538, 189. (c) Beck, W.;
Burger, K.; Felhammer, W. P. Chem. Ber. 1971, 104, 1816. (d)
Chisholm, M. H.; Hammond, C. E.; Ho, D.; Huffman, J . C. J . Am. Chem.
Soc. 1986, 108, 7860. (e) Dormond, A.; Aaliti, A.; Mo¨ıse, C. J . Chem.
Soc., Chem. Commun. 1985, 1231. (f) Glueck, D. S.; Hollander, F. J .;
Bergman, R. G. J . Am. Chem. Soc. 1989, 111, 2719. (g) Zanella, P.;
Brianese, N.; Casellato, U.; Ossola, F.; Porchia, M.; Rossetto, G.;
Graziani, R. J . Chem. Soc., Dalton Trans. 1987, 2039.
(12) Regragui, R.; Dixneuf, P. H.; Taylor, N. J .; Carty, A. J .
Organometallics 1984, 3, 814.
10.1021/om000461t CCC: $19.00 © 2000 American Chemical Society
Publication on Web 09/28/2000

4590 Organometallics, Vol. 19, No. 22, 2000
Cristofani et al.
Ta ble 1. Sign ifica n t NMR (δ (p p m ), J (Hz)) a n d IR
(cm -1) P a r a m eter s for Com p lexes 1-4
Sch em e 1
1a
2
3
4
δP
δP
δPt
δPt
δH
295.8
60.7
-5483
-5220
6.2
295.0
62.7
-5549
-5162
6.3
288.6
61.2
-5586
-5252
6.3
289.3
61.2
-5573
-5249
6.3
1
2
1
2
2
2J P
1J P
1J P
2J P
1J P
1J P
3J P
38
41
41
41
1P2
2623
2431
31
4660
328
14
27
185
2277
1956(νCO
2665
2402
46
4695
324
15
17
178
2264
1936
2647
2543
41
4724
321
18
18
127
2259
1975
2642
2533
38
4716
318
17
18
188
2256
2029
1Pt1
1Pt2
2Pt2
2Pt1
2H2
1H2
2J Pt
1J Pt
νPH
1H2
1Pt2
b
To the best of our knowledge, the insertion of isoni-
triles into a bridging phosphide is yet unreported.
νCN
)
a
b
From ref 13. νCN of the free ligands 2125 (p-tolyl-NC), 2134
(ButNC), and 2146 cm-1 (PhCH2NC).
Resu lts a n d Discu ssion
charge. A limited number of complexes satisfy all (or
nearly all) these conditions; for example, the neutral
M(0) derivatives Fe(PMe3)2(CNR)3,14 M(CNR)2(dppe)2
(M ) Mo, W),15 trans-[Mo(PhNC)2(Me8[16]aneS4),16 and
Su bstitu tion Rea ction s. Orange-yellow toluene so-
lutions of [Pt2(µ-PBut ) (PBut H)(CO)] (1)13 were reacted
2 2
2
with equimolar amounts of organic isonitriles (RNC, R
) p-tolyl, But, PhCH2), yielding deep orange solutions
of the corresponding monosubstituted derivatives [Pt2-
(µ-PBut ) (PBut H)(CNR)] (2, R ) p-tolyl; 3, R ) But; 4,
Mo(η6-PhPMePh)(CNCMe3)(PMePh2)2 all exhibit νCN
17
values below 2000 cm-1
.
2 2
2
When the molar ratio RNC/1 was increased, complex
1 was cleanly converted into the corresponding bis-
R ) PhCH2) (Scheme 1). The new complexes were
formed in nearly quantitative yields (as observed by
NMR; much faster reactions occur with the aromatic
ligand (see the Experimental Section)) and were isolated
as orange solids and characterized by elemental analy-
ses and IR and multinuclear NMR spectroscopy (Table
1).
As can be seen by comparing the data of Table 1, 31P
and 195Pt NMR spectra are very similar to the corre-
sponding spectra of complex 1, which have been thor-
oughly discussed in a previous paper,13 where the
crystal and molecular structure of 1 was also reported.
Therefore, the spectral features will not be further
discussed.
(isonitrile) derivatives [Pt(µ-PBut )(CNR)]2 (5, R ) p-
2
tolyl; 6, R ) But; 7, R ) PhCH2); the reactions are nearly
quantitative (31P NMR), and complexes 5-7 were
isolated as analytically pure red-orange powders in
satisfactory yields (48-72%). The 31P{1H} NMR spectra
exhibit the expected pattern (a singlet with 195Pt satel-
lites, comprising a 1:8:18:8:1 quintet with J app ) 1J PPt
/
2)18 at low fields (297.7 ppm, 1J PPt ) 2557 Hz for 5; 293.1
ppm, 1J PPt ) 2632 Hz for 6; 294.7 ppm, 1J PPt ) 2649 Hz
195
for 7) for the equivalent P-bridging nuclei, and the
-
Pt{1H} NMR spectra give a unique signal for the
equivalent Pt nuclei (triplets (1J PPt as above) at -5177,
-5264, and -5268 ppm, respectively). H and 13C{1H}
1
The very low νCN frequencies in the IR spectra of 2
and 3 deserve a brief comment. First of all they show,
together with the low value of νCO found in complex 1,
NMR spectra (see Experimental Section) were consis-
tent with structures 5-7, and the stretching vibrations
of the CN groups give strong and broad IR absorptions
that the Pt2(µ-PBut ) core has a substantial π basicity,
at 2063, 2033 (5), 2175, 2167 (6), and 2073 (7) cm-1
.
2 2
enhanced by the good σ-donor properties of the PBut H
2
Reasonably, the increase of νCN, compared to that
observed in 2-4, is due to the substitution of a phos-
ligand. Moreover, it should be noted that most of the
known values of νCN for terminally bonded isonitriles
fall above 2000 cm-1; however, it should be kept in mind
that, although a great number of isonitrile complexes
are known, very few are directly comparable to com-
plexes 2-4. For a meaningful comparison (1) the
complex should bear only one isonitrile ligand, together
with other good σ-donor ligands, and the metal(s) should
be in a relatively low oxidation state and (2) it should
not bear other good π-acceptor ligands or a positive
(14) J ones, W. D.; Foster, G. P.; Putinas, J . M. Inorg. Chem. 1987,
26, 2120.
(15) Chatt, J .; Elson, C. M.; Pombeiro, A. J . L.; Richards, R. L.;
Royston, G. H. D. J . Chem. Soc., Dalton Trans. 1978, 165.
(16) Adachi, T.; Sasaki, N.; Ueda, T.; Kaminaka, M.; Yoshida, T. J .
Chem. Soc., Chem. Commun. 1989, 1320.
(17) Luck, R. L.; Morris, R. H.; Sawyer, J . F. Organometallics 1984,
3, 247.
(18) (a) Hill, G. S.; Puddephatt, R. J . J . Am. Chem. Soc. 1996, 118,
8745. (b) Mole, L.; Spencer, J . L.; Litster, S. A.; Redhouse, A. D.; Carr,
N.; Orpen, A. G. J . Chem. Soc., Dalton Trans. 1996, 2315. (c) Knobler,
C. B.; Kaesz, H. D.; Minghetti, G.; Bandini, A. L.; Banditelli, G.; Bonati,
F. Inorg. Chem. 1983, 22, 2324. (d) Tulip, T. H.; Yamagata, T.; Yoshida,
T.; Wilson, R. D.; Ibers, J . A.; Otsuka, S. Inorg. Chem. 1979, 18, 2239.
(13) Leoni, P.; Chiaradonna, G.; Pasquali, M.; Marchetti, F. Inorg.
Chem. 1999, 38, 253.

Isonitrile Insertion into a Phosphido Bridge
Organometallics, Vol. 19, No. 22, 2000 4591
Ch a r t 1
Ch a r t 2
phine with a less σ-basic isonitrile and to the sharing
of π-donation on two RNC ligands in 5-7.
1
) 215 Hz, and J PtPt ) 2100 Hz. This set of coupling
constants also reproduces nicely the weak lines due to
the isotopomer containing two 195Pt nuclei, as well as
the 195Pt{1H} spectrum (experimental and calculated
spectra are provided in the Supporting Information).
1H and 13C{1H} NMR spectra (see Experimental
Section) were consistent with structure 9, and the
stretching vibrations of the CN groups give a strong and
broad IR absorption at 2107 cm-1 and a less intense
absorption at 1542 cm-1, which can be assigned to the
stretching of the phosphaiminoacyl CdN bonds.
As was the case for complex 8, although more slowly,
complex 9 deinserts the isonitrile molecules if dissolved
in solution without an excess of p-tolyl isocyanide, to
give complex 5 quantitatively.
In ser tion Rea ction s. While complexes 6 and 7
remain unchanged in the presence of a large excess of
the corresponding isonitrile ligand, complex 5 reacts
further. After the addition of 3.5 equiv of p-tolylisoni-
trile, a toluene solution of complex 1 soon becomes (1
h) deep red and contains only [Pt2(µ-PBut ){µ,η2-P(But )C-
2
2
(dNAr)}(CNAr)2] (8) (Chart 1), arising from the inser-
tion of an isonitrile molecule into one of the Pt-P(µ)
bonds.
The structure of complex 8 was assigned on the basis
of its spectroscopic features and confirmed by an X-ray
crystallographic study (see below).
Two signals were observed in the 31P{1H} NMR
spectrum: one was still found in a region typical for
bridging phosphides spanning a metal-metal bond19
(197.0 ppm, P1), while the other was remarkably high-
field-shifted (-37.5 ppm, P2). Both appear as a central
doublet (2J PP ) 204 Hz) flanked by 195Pt satellites,
P r oton ation Reaction s. Iminoacyl derivatives formed
by isonitrile insertion into M-C bonds can be proto-
nated or alkylated at nitrogen to give Fisher carbenes.20
The same holds true for the new phosphaiminoacyls
8 and 9. By addition of an equimolar amount of CF3-
SO3H at room temperature, a red solution of complex 8
turned immediately brown and was shown (31P NMR)
to contain a unique new product. This was isolated as
a red microcrystalline solid in 55% yield and identified
as [Pt2(µ-PBut ){µ,η2-P(But )C(NHAr)}(CNAr)2]CF3SO3
1
1
yielding the values of J P Pt ) 2820 Hz, J P Pt ) 2351
1
1
2
1 2
Hz, 1J P Pt ) 2280 Hz, and J P Pt ) 257 Hz (assignment
2
1
2
2
facilitated by comparison with the 195Pt{1H} NMR
spectrum). This exhibits two doublets of doublets (J PPt
as above) at -4928.5 and -4523.3 ppm (with satellites
2
2
1
yielding the value of J PtPt ) 293 Hz), which were
(10) (Chart 2). Two doublets (2J PP ) 215 Hz) were
observed in the 31P{1H} NMR spectrum (CDCl3, 293 K)
at 208.4 (P1) and 27.0 ppm (P2), both flanked by 195Pt
respectively assigned to Pt1 and Pt2. H and 13C{1H}
1
NMR spectra (see Experimental Section) were consis-
tent with structure 8. The stretching vibrations of the
CN groups give strong and broad absorptions at 2073,
satellites (1J P Pt ) 3062, 2632 Hz, J P Pt ) 2380 Hz,
1
1
2
2J P Pt ) 216 Hz; note the large downfield shift of P2 (∆δ
2
2040 cm-1 and a less intense absorption at 1537 cm-1
,
) 64.5 ppm) compared to the corresponding phosphorus
in 8). The 13C{1H} and 1H NMR spectra (see Experi-
mental Section) were consistent with the structure given
for 10. The latter shows for the NH proton a broad
resonance at 14.3 ppm with satellites (3J HPt ) 120 Hz);
this large coupling constant implies a trans disposition
of the nuclei.21
which can be assigned to the stretching of the phos-
phaiminoacyl CdN bond. Complex 8 is stable in the
solid state, but in solution, without an excess of p-tolyl
isocyanide, slowly deinserts the isonitrile molecule,
yielding 5.
When the excess of p-tolyl isocyanide is increased
further (ArNC:1 g 5), a second molecule of the ligand
is inserted into a Pt-P(µ) bond of the remaining
The 195Pt{1H} NMR spectrum (CDCl3, 293 K) consists
of two doublets of doublets at -5085 (1J PtP ) 2380, 3062
phosphide, yielding [Pt{µ,η2-P(But )C(dNAr)}(CNAr)]2
Hz; Pt1) and - 4420 (1J PtP ) 2632 Hz, J PtP ) 216 Hz;
2
2
(9) (Chart 1), a complex with a centrosymmetric [PtPC]2
core. Accordingly, a single signal was observed in the
195Pt{1H} (-4364.3 ppm) and in the 31P{1H} (-15.1
ppm) NMR spectra (C6D6, 293 K). The latter appears
as a central singlet for the equivalent P nuclei. Since
these nuclei lose their magnetic equivalence in the two
isotopomers containing one 195Pt nucleus, the corre-
sponding satellites (eight lines with intensity ratio 1:2:
1:2:2:1:2:1) cannot be interpreted in terms of first-order
spectra, but were adequately simulated by using the
Pt2) ppm. The latter is further split in the proton-
coupled spectrum by the coupling to the NH proton.
The di-inserted derivative 9 reacts analogously with
2 equiv of CF3SO3H, yielding the bis(carbene) [Pt{µ,η2-
P(But )C(NHAr)}(CNAr)]2(CF3SO3)2 (11). The NMR pa-
2
rameters (see Experimental Section) compare well with
the corresponding parameters of complex 10 and will
not be discussed further. The structure of 11 has been
confirmed by an X-ray crystallographic study (see
below).
1
following values: J PPt ) 1455 Hz, 2J PPt ) -265 Hz, 3J PP
(20) (a) Yamamoto, Y.; Yamazaki, H. Bull. Chem. Soc. J pn. 1975,
48, 3691. (b) Treichel, P. M.; Wagner, K. P.; Hess, R. W. Inorg. Chem.
1973, 12, 1471.
(21) Michelin, R. A.; Bertani, R.; Mozzon, M.; Zanotto, L.; Benetollo,
F.; Bombieri, G. Organometallics 1990, 9, 1449.
(19) (a) Garrou, P. E. Chem. Rev. 1981, 81, 229. (b) Carty, A. J .;
MacLaughlin, S. A.; Nucciarone, D. In 31P NMR Spectroscopy in
Stereochemical Analysis: Organic Compounds and Metal Complexes;
Verkade, J . B., Quin, L. D., Eds., VCH: Weinheim, Germany, 1987.

4592 Organometallics, Vol. 19, No. 22, 2000
Cristofani et al.
F igu r e 1. ORTEP view of the molecular structure of 8.
Thermal ellipsoids are drawn at 50% probability.
F igu r e 2. ORTEP view of the molecular structure of the
cation 112+. Thermal ellipsoids are drawn at 50% prob-
ability.
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for
[P t2(µ-P Bu t2){µ,η2-P (Bu t2)C(dNAr )}(CNAr )2] (8) a n d
[P t{µ,η2-P (Bu t2)C(NHAr )}(CNAr )]2(CF 3SO3)2 (11)
moiety. The Pt-Pt separation falls in the expected range
and is shorter but comparable to that found in the cation
t
[Pt2(µ-PBu2 )2(H)(PButH)2][C3(CN5)5] (2.6473(5) Å),22 in
8
11
Pt1-Pt2
Pt1-P1
Pt2-P1
Pt2-P2
Pt1-C1
Pt2-C12
Pt1-C11
Pt2-C21
P1-C12
P2-C1
C11-N11
C21-N21
C1-N1
C12-N12
N1-C2
N12-C22
2.5980(3)
2.289(1)
2.298(1)
2.308(1)
2.073(5)
2.5838(6)
2.303(3)
keeping with the different electronic nature of the
terminal ligands.
The two Pt-P1 distances are different (2.289(1) and
2.298(2) Å, respectively) as can be expected from the
different trans influences exerted by P2 and C1. The
C1-N1 and N1-C2 separations, at 1.287(7) and 1.412-
(7) Å, and the C1-N1-C2 angle (120.4(4)°) are consis-
tent with the presence of a CdN-C moiety. All other
distances are unexceptional.
The conformation of the isonitrile substituents can
best be described by the dihedral angles between the
least-squares planes through the p-tolyl rings and the
coordination plane defined by atoms Pt1, Pt2, P1, and
P2. We found, for the two terminal rings, angles of 19.9-
(2) and 18.6(3)°, respectively; the ring bond to atom N1
makes an angle of 79.9(1)° with the aforementioned
plane.
2.301(3)
2.04(1)
2.01(1)
1.97(1)
1.96(1)
1.84(1)
1.84(1)
1.16(2)
1.17(2)
1.32(2)
1.31(2)
1.44(2)
1.43 (1)
1.911(6)
1.923(6)
1.842(5)
1.177(7)
1.184(7)
1.287(7)
1.412(7)
Pt2-Pt1-C11
Pt1-Pt2-C21
Pt1-C11-N11
Pt2-C21-N21
Pt1-P1-Pt2
P1-Pt1-C11
C1-Pt1-C11
P1-Pt2-C21
P1-Pt1-C1
168.3(1)
170.9(2)
174.5(5)
178.1(5)
69.01(4)
112.7(2)
106.9(2)
115.6(2)
140.4(1)
130.87(5)
159.8(4)
164.3(5)
171.2(13)
175.3(12)
X-r a y Str u ctu r e of 11. An Ortep view of the cation
is given in Figure 2, while relevant geometric param-
eters are listed in Table 2. The most significant differ-
ences in the coordination geometry, compared to that
of compound 8, are (i) a small but significant shortening
of the Pt-Pt separation (2.5838(6) vs 2.5980(3) Å), (ii)
a lengthening of the terminal Pt-C distances (average
values 1.965(7) and 1.917(8) Å, respectively), and (iii) a
significant widening of the angles C11-N11-C111
(176.3(15) vs 168.5(6)°) and C21-N21-C211 (176.5(15)
vs 168.0(6)°). These changes are consistent with the
expected reduced back-donation of platinum in cation
103.4(4)
98.6(5)
158.0(3)
P1-Pt2-P2
P2-Pt2-C12
P2-Pt2-C21
C12-Pt2-C21
Pt1-P1-C12
Pt2-P2-C1
157.4(3)
99.6(4)
103.1(5)
93.3(4)
113.5(2)
99.1(2)
93.5(4)
Pt1-C1-P2
Pt1-C1-N1
P2-C1-N1
Pt2-C12-P1
Pt2-C12-N12
P1-C12-N12
C1-N1-C2
C12-N12-C22
C11-N11-C111
C21-N21-C211
100.5(2)
138.3(4)
120.9(4)
104.6(5)
130.2(9)
124.2(9)
105.0(5)
129.1(8)
124.8(8)
123.8(11)
123.5(10)
176.3(15)
176.5(15)
112+
.
As expected, the C1-N1 and C12-N12 bond lengths
(average 1.315(7) Å) are longer than that found in 8
(1.287(7) Å), even though the lower precision of the
structural determination of 11 prevents a detailed
discussion of the changes induced by the protonation of
the N atoms, as the differences in bonding parameters
are marginally significant at the 3σ level; however, it
may be noted that the H atoms bonded to N1 and N12
can be clearly located in the difference Fourier maps,
thus confirming the proposed bonding scheme.
120.4(4)
168.5(6)
168.0(6)
Pt1-P1-C12-Pt2
Pt2-P2-C1-Pt1
P2-C1-N1 C21
16.3(5)
17.2(5)
158(1)
164(1)
0.1(2)
177.9(4)
P1-C12-N12-C22
X-r a y Str u ctu r e of 8. An Ortep view of compound 8
is given in Figure 1, while selected bond lengths and
angles are listed in Table 2. The structure consists of
discrete Pt dimers held together by van der Waals
forces. The immediate coordination sphere of the two
metal atoms comprises a metal-metal bond (2.5980(3)
Å), the two terminal p-tolyl isocyanide ligands, the
intact bridging phosphido group and the “R2P-CNR”
The steric crowding induced by the double insertion
into the phosphido bridges is clearly reflected in the
changes of the dihedral angles between the least-
(22) Leoni, P.; Pasquali, M.; Fortunelli, A.; Germano, G.; Albinati,
A. J . Am. Chem. Soc. 1998, 120, 9564.

Isonitrile Insertion into a Phosphido Bridge
Organometallics, Vol. 19, No. 22, 2000 4593
resonances of the solvent (128 ppm). See Table 1 for 31P and
195Pt NMR parameters.
squares planes through the p-tolyl rings and the coor-
dination plane defined by atoms Pt1, Pt2, P1, and P2.
Thus, the dihedral angles between the coordination
plane and the terminal rings are 41.7(5) and 36.7(6)°,
respectively; those made by the bridging groups are
39.9(4) and 37.5(4)°, respectively.
P r ep a r a tion of [P t2(µ-P Bu t2)2(CN-p-tolyl)2] (5). A tolu-
ene (15 mL) solution of p-tolyl isocyanide (1.38 mmol) was
added to a yellow-orange toluene (80 mL) solution of complex
1 (587 mg, 0.687 mmol). The solution quickly turned red, and
after a few minutes, the solvent was evaporated and the
residue suspended in acetonitrile (20 mL). An orange powder
was isolated by filtration, washed with acetonitrile, and
vacuum-dried (450 mg, 0.492 mmol, 72%). Anal. Calcd for
Exp er im en ta l Section
Gen er a l Da ta . The reactions were carried out under a
nitrogen atmosphere, by using standard Schlenk techniques.
[Pt2(µ-PBut )2(PBut H)(CO)] (1) was prepared as previously
C
32H50N2P2Pt2: C, 42.0; H, 5.51; N, 3.06. Found: C, 41.6; H,
5.63; N, 3.10. IR (Nujol, KBr): 2063, 2033 (broad, νCN) cm-1
.
1H NMR (C6D6, 293 K): δ (ppm) 7.09 (d, J HH ) 8 Hz, 4H, Ar
3
2
2
described.13
3
H), 6.68 (d, J HH ) 8 Hz, 4H, Ar H), 1.88 (s, 6H, p-CH3), 1.61
(virtual triplet, [3J HP + J HP] ) 7 Hz, 36H, µ-PBut). 13C{1H}
5
Solvents were dried by conventional methods and distilled
under nitrogen prior to use. IR spectra (Nujol mulls, KBr) were
recorded on a Perkin-Elmer FT-IR 1725X spectrophotometer.
NMR spectra were recorded on a Varian Gemini 200 BB
instrument; frequencies are referenced to the residual reso-
nances of the deuterated solvent (H, 13C), 85% H3PO4 (31P),
and H2PtCl6 (195Pt).
P r ep a r a tion of [P t2(µ-P Bu t2)2(P Bu t2H)(CN-p-tolyl)] (2).
A toluene (0.2 mL) solution of p-tolyl isocyanide (0.109 mmol)
was added by syringe to a yellow-orange toluene (15 mL)
solution of complex 1 (91 mg, 0.106 mmol). The solution quickly
turned deep orange, and after a few minutes, the solvent was
evaporated and the residue suspended in acetonitrile (10 mL).
An orange powder was isolated by filtration, washed with
acetonitrile, and vacuum-dried (42 mg, 0.044 mmol, 42%).
Anal. Calcd for C32H62NP3Pt2: C, 40.7; H, 6.62; N, 1.48.
Found: C, 40.2; H, 6.53; N, 1.48. IR (Nujol, KBr): 2264 (νPH),
1936 (νCN) cm-1. 1H NMR (C6D6, 293 K): δ (ppm) 7.16 (m, 2H,
NMR (C6D6, 293 K): δ (ppm) 136.7, 129.8 (weak singlets, Cipso
and p-C), 130.3, 124.4 (s, o-C and m-C), 40.9 (m, PCCH3), 32.7
(m, PCCH3), 20.8 (s, p-CH3). See Results and Discussion for
31P and 195Pt NMR parameters
Complexes 6 and 7 were prepared by the same procedure,
although they required longer reaction times (12 h at 20 °C
and 72 h at 30 °C, respectively) and higher excess of the
corresponding isonitrile (yield 54 and 48%, respectively). The
reactions were shown (31P NMR) to be nearly quantitative
before isolation of the products.
Complex 6: Anal. Calcd for C26H54N2P2Pt2: C, 36.9; H, 6.43;
N, 3.31. Found: C, 37.2; H, 6.39; N, 3.32. IR (Nujol, KBr):
2175, 2167 (broad, νCN) cm-1. H NMR (toluene-d8, 293 K): δ
1
(ppm) 1.74 (virtual triplet, [3J HP + 5J HP] ) 6 Hz, 36H, µ-PBut),
1.46 (s, 18H, CNBut). 13C{1H} NMR (C6D6, 293 K): δ (ppm)
40.3 (weak broad overlapping multiplets, CCH3), 33.2 (broad
s, PCCH3), 31.0 (broad s, CN-CCH3). See Results and Discus-
sion for 31P and 195Pt NMR parameters.
1
3
Ar H), 6.71 (m, 2H, Ar H), 6.33 (dt, J HP ) 324, J HP ) 15 Hz,
with 195Pt satellites, 2J HPt ) 17 Hz, P-H), 1.90 (s, 3H, p-CH3),
Complex 7: Anal. Calcd for C32H50N2P2Pt2: C, 42.0; H, 5.51;
N, 3.06. Found: C, 42.2; H, 5.49; N, 3.04. IR (Nujol, KBr): 2073
1.55 (broad s, 36H, µ-PBut ), 1.35 (d, J HP ) 14 Hz, 18H,
3
2
PHBut ). 13C{1H} NMR (C6D6, 293 K): δ (ppm) 136.0 (s, Cipso),
2
(broad, νCN) cm-1 1H NMR (C6D6, 293 K): δ (ppm) 7.4-6.7
.
1
1
(m, 10H, Ar H), 4.31 (s, with satellites, 4J HPt ) 9 Hz, 4H, CH2),
1.58 (virtual triplet,19 [3J HP + 5J HP] ) 7 Hz, 36H, µ-PBut).13C-
{1H} NMR (C6D6, 293 K): δ (ppm) 48.9 (s, CH2), 40.2 (s,
PCCH3), 32.9 (br s, PCCH3); the aromatic region is poorly
resolved due to overlapping with the resonances of the solvent
(128 ppm). See Results and Discussion for 31P and 195Pt NMR
parameters.
130.3 (s, CH [d, J CH ) 160 Hz]), 129.9 (s, CH [d, J CH ) 160
Hz]), 40.7 (s, PCCH3), 34.7 (s, PCCH3), 33.6 (m, PCCH3 [quart,
1J CH ) 125 Hz]), 31.5 (d, 2J CP ) 6.7 Hz, with satellites, 3J CPt
)
1
23 Hz, PCCH3 [quart, J CH ) 120 Hz]), 21.1 (s, p-CH3 [quart,
1J CH ) 127 Hz]) (features from the proton-coupled spectrum
are shown in brackets). See Table 1 for 31P and 195Pt NMR
parameters.
P r epar ation of [P t2(µ-P Bu t2){µ,η2-P (Bu t2)C(dN-p-tolyl)}-
(CN-p-tolyl)2] (8). A toluene (1.5 mL) solution of p-tolyl
isocyanide (0.787 mmol) was added to a yellow-orange toluene
(20 mL) solution of complex 1 (192 mg, 0.225 mmol). The
solution quickly turned deep orange and slowly (1 h) deep red,
the solvent was evaporated, and the residue suspended in
n-hexane (15 mL). A green-brown crystalline solid was isolated
by filtration and vacuum-dried (107 mg, 0.102 mmol, 46%).
Anal. Calcd for C40H57N3P2Pt2: C, 46.5; H, 5.57; N, 4.07.
Found: C, 46.1; H, 5.53; N, 4.03. IR (Nujol, KBr): 2073, 2040
Complexes 3 and 4 were prepared by the same procedure,
although they required longer (12 h) reaction times (yields 44
and 53%, respectively). The reactions were shown (31P NMR)
to be nearly quantitative before isolation of the products.
Complex 3: Anal. Calcd for C29H55NP3Pt2: C, 37.7; H, 6.14;
N, 2.06. Found: C, 37.3; H, 6.09; N, 2.02. IR (Nujol, KBr): 2259
(νPH), 1975 (νCN) cm-1
.
1H NMR (C6D6, 293 K): δ (ppm) 6.34
1
3
2
(dt, J HP ) 321, J HP ) 18 Hz, with satellites, J HPt ) 18 Hz,
1H, P-H), 1.57 (virtual triplet,23 [3J HP + J HP] ) 7 Hz, 36H,
5
µ-PBut), 1.36 (d, 3J HP ) 14 Hz, 18H, PHBut), 1.22 (s, 9H, CN-
But). 13C{1H} NMR (C6D6, 293 K): δ (ppm) 40.9 (s, CCH3), 40.4
(broad, νCN), 1537 (νCdN) cm-1
.
1H NMR (CD2Cl2, 293 K): δ
2
2
(s, CCH3), 40.1 (s, CCH3), 33.6 (m, µ-PCCH3), 31.5 (d, J CP
)
(ppm) 7.30 (m, 4H, Ar H), 7.12 (d, J HH ) 8 Hz, 2H, Ar H),
3
2
7 Hz, with satellites, J CPt ) 24 Hz, P(H)CCH3) 31.2 (s, CN-
CCH3). See Table 1 for 31P and 195Pt NMR parameters.
Complex 4: Anal. Calcd for C32H60NP3Pt2: C, 40.8; H, 6.42;
N, 1.49. Found: C, 40.3; H, 6.50; N, 1.47. IR (Nujol, KBr): 2256
7.01 (d, J HH ) 8 Hz, 2H, Ar H), 6.83 (m, 4H, Ar H), 2.40 (s,
3H, p-CH3), 2.31 (s, 3H, p-CH3), 2.10 (s, 3H, p-CH3), 1.41 (d,
3
3J HP ) 13 Hz, 18H, PCCH3), 1.34 (d, J HP ) 15 Hz, 18H,
PCCH3). 13C{1H} NMR (CDCl3, 293 K): δ (ppm) 130.5 (s, CH,
[d, 159 Hz]), 129.8 (s, CH, [d, 164 Hz]), 128.9 (s, CH, [d, 154
Hz]), 125.2 (s, CH, [d, 167 Hz]), 125.0 (s, CH, [d, 167 Hz]),
121.0 (s, CH, [d, 169 Hz]), 40.0 (s, PCCH3), 38.4 (s, PCCH3),
33.3 (m, PCCH3, [q, 126 Hz]), 29.5 (m, PCCH3, [q, 127 Hz]),
21.7 (2 overlapping singlets, p-CH3, [q, 130 Hz), 21.1 (s, p-CH3,
[q, 129 Hz]) (features from the proton-coupled spectrum are
shown in brackets). See Results and Discussion for 31P and
195Pt NMR parameters. The reaction was shown (31P NMR) to
be nearly quantitative before isolation of the product.
(νPH), 2029 (νCN) cm-1. H NMR (C6D6, 293 K): δ (ppm) 7.3-
1
1
3
7.0 (m, 5H, Ar H), 6.34 (dt, J HP ) 317, J HP ) 17 Hz, with
2
satellites, J HPt ) 18 Hz, 1H, P-H), 4.41 (s, with satellites,
4J HPt ) 8 Hz, 2 H, CNCH2), 1.57 (virtual triplet, [3J HP + 5J HP
]
) 10 Hz, 36H, µ-PBut), 1.38 (d, J HP ) 14 Hz, 18H, PHBut).
13C{1H} NMR (C6D6, 293 K): δ (ppm) 49.6 (s, CH2), 40.7-28.0
(weak broad overlapping multiplets, CCH3), 33.5 (m, µ-PCCH3),
3
2
31.5 (d, J CP ) 7 Hz, with broad satellites, P(H)CCH3); the
aromatic region is poorly resolved due to overlapping with the
P r ep a r a tion of [P t{µ,η2-P (Bu t2)C(dN-p-tolyl)}(CN-p-
tolyl)]2 (9). A toluene (2.5 mL) solution of p-tolyl isocyanide
(1.28 mmol) was added to a yellow-orange toluene (40 mL)
(23) Crabtree, R. H. The Organometallic Chemistry of the Transition
Metals; Wiley: New York, 1988.

4594 Organometallics, Vol. 19, No. 22, 2000
Cristofani et al.
Ta ble 3. Exp er im en ta l Da ta for th e X-r a y
solution of complex 1 (219 mg, 0.256 mmol). The solution
quickly turned deep orange and slowly (1 h) deep red, the
solvent was evaporated, and the residue was suspended in
n-hexane (10 mL). A deep green powder was isolated by
filtration and vacuum-dried (170 mg, 0.147 mmol, 57%). Anal.
Calcd for C48H64N4P2Pt2: C, 50.2; H, 5.61; N, 4.88. Found: C,
50.5; H, 5.58; N, 4.83. IR (Nujol, KBr): 2107 (broad, νCN), 1542
Diffr a ction Stu d y of Com p ou n d s:
[P t2(µ-P Bu t2){µ,η2-P (Bu t2)C(dNAr )}(CNAr )2] (8) a n d
[P t{µ,η2-P (Bu t2)C(NHAr )}(CNAr )]2(CF 3SO3)2 (11)
8
11
formula
mol wt
data coll. T, K
radiation
C
40H57N3P2Pt2
C50H66F6N4O6P2Pt2S2
1449.31
293(2)
1032.03
200(2)
1
(νCdN) cm-1. H NMR (C6D6, 293 K): δ (ppm) 7.60 (m, 4H, Ar
H), 7.10 (m, 4H, Ar H), 6.64 (m, 8H, Ar H), 2.02 (s, 6H, p-CH3),
1.84 (s, 6H, p-CH3), 1.65 (m, 36H, PCCH3). 13C{1H} NMR
(C6D6, 293 K): δ (ppm) 129.4 (s, CH), 128.0 (s, CH), 124.9 (s,
CH), 121.2 (s, CH), 36.9 (s, PCCH3), 29.7 (s, PCCH3), 20.7 (br
s, p-CH3). See Results and Discussion for 31P and 195Pt NMR
parameters. The reaction was shown (31P NMR) to be nearly
quantitative before isolation of the product.
Mo KR (graphite monochromated,
λ ) 0.710 69 Å)
cryst syst
space group
a, Å
triclinic
monoclinic
P21/n (No. 14)
13.0470(6)
10.4100(5)
43.706 (2)
90.0
90.43(1)
90.0
5935.9(5)
4
P1h (No. 2)
11.1702(1)
11.1723(1)
18.6149(2)
95.965(1)
107.333(1)
108.290(1)
2062.77(3)
2
b, Å
c, Å
R, deg
â, deg
γ, deg
V, Å3
P r ep a r a t ion of [P t 2(µ-P Bu t 2){µ,η2-P (Bu t 2)C(NH Ar )}-
(CNAr )2]CF 3SO3 (10). A red toluene (15 mL) solution of
complex 8 (139 mg, 0.135 mmol) quickly turned brown after
the addition of CF3SO3H (12 µL, 0.136 mmol), and a red solid
started to precipitate out. The suspension was stirred for 1 h
at ambient temperature, and the solid was isolated by filtra-
tion, washed with n-hexane, and vacuum-dried (86 mg, 55%
yield). Anal. Calcd for C41H58F3N3O3P2Pt2S: C, 38.6; H, 4.90;
N, 3.37. Found: C, 39.1; H, 4.93; N, 3.35. 1H NMR (CDCl3,
Z
F
(calcd), g cm-3
1.662
6.881
1.621
4.898
µ, mm-1
θ range, deg
1.17 < θ < 25.66 1.63 < θ < 29.45
0.291-0.180
transmissn factors
1.000-0.732
15105
no. of indep rflns, no 6855
no. of obsd rflns
(|Fo| > 4.0σ(|F|))
no. of params, nv
(no. of restraints)
R1, obsd rflns
(all data)a
5805
12615
293 K): δ (ppm) 14.3 (br s, with 195Pt satellites, J HPt ) 120
3
Hz, 1 H, NH), 8.0 (d, J HH ) 7.8 Hz, 2 H, Ar H), 6.9 (m, 4 H, Ar
H), 6.7 (d, J HH ) 8.1 Hz, 2 H, Ar H), 6.6 (d, J HH ) 8.3 Hz, 2 H,
Ar H), 6.5 (d, J HH ) 8.3 Hz, 2 H, Ar H), 1.95 (s, 3 H, CH3), 1.9
(s, 3 H, CH3), 1.8 (s, 3 H, CH3), 1.4 (m, 36 H, CH3). 13C{1H}
NMR (CDCl3, 293 K): δ (ppm) 139.8 s [s], 139.5 s [s], 122.9 s
[s], 131.2 s [d, 1J CH ) 163 Hz], 130.8 s [d, 1J CH ) 163 Hz], 130.3
424
621 (3)
0.0258 (0.0351)
0.0583 (0.0629)
0.0763 (0.0924)
0.1204 (0.1312)
wR2, obsd rflns
(all data)b
GOFc
1.088
0.784
1
1
s [d, J CH ) 172 Hz], 129.3 s [d, J CH ) 160 Hz], 126.9 s [d,
1J CH ) 164 Hz], 125.7 s [d, J CH ) 164 Hz], 40.8 s [s], 39.3 s
1
R ) ∑(|Fo - (1/k)Fc|)/∑|Fo|. wR2 ) [∑w(Fo - (1/k)Fc2)2/
a
b
2
∑w|Fo | ]. c GOF ) [∑w(Fo - (1/k)Fc2)2/(no - nv)]1/2
.
2 2
2
[s], 33.0 s [q, 1J CH ) 134 Hz], 30.1 s [q, 1J CH ) 135 Hz], 21.6 (3
1
overlapping s) [q, J CH ) 128 Hz] (features from the proton-
coupled spectrum are shown in brackets). See Results and
Discussion for 31P and 195Pt NMR spectra. IR (Nujol, KBr):
2105 (νCN), 1263, 1153, 1030, 637 (uncoordinated triflate)24
Prismatic single crystals of both compounds were mounted,
for the data collection, on a glass fiber at a random orientation,
on a Bruker SMART CCD diffractometer at 200 K for 8 and
at room temperature for 11.
cm-1
.
P r ep a r a tion of [P t{µ,η2-P (Bu t2)C(NHAr )}(CNAr )]2(CF 3-
SO3)2 (11). A red toluene (10 mL) solution of complex 9 (70
mg, 0.061 mmol) quickly turned brown after the addition of
CF3SO3H (12 µL, 0.136 mmol), and an orange solid started to
precipitate out. The suspension was stirred for 1 h at ambient
temperature, and the solid was filtered, washed with Et2O,
and vacuum-dried (52 mg, 57%). Anal. Calcd for C50H66F6N4O6P2-
Pt2S2: C, 41.4, H, 4.59; N, 3.87. Found: C, 41.2; H, 4.59; N,
3.91.31P{1H} NMR (CDCl3, 293 K): δ (ppm) 37.8 (s, with 195Pt
The space groups were unambiguously determined from the
systematic absences, while the cell constants were refined at
the end of the data collection with the data reduction software
SAINT.25 Data were collected by using ω scans in steps of 0.3°;
for compound 8 2142 frames were collected with a counting
time of 20 s, while for 11 2450 frames were measured, each
being counted for 20 s. A list experimental conditions for the
data collection is given in Table S1 in the Supporting Informa-
tion.
The measured intensities were corrected for Lorentz and
polarization factors25 and empirically for absorption using the
SADABS program.26
Selected crystallographic and other relevant data are listed
in Table 3 and in Table S1.
2
1
2
satellites, J PP ) 90, J PPt ) 1820, J PPt ) - 260 Hz from
simulated spectra). 1H NMR (CDCl3, 293 K): δ (ppm) 13.5 (br
3
t, J = 15 Hz, with broad 195Pt satellites, J HPt ) 128 Hz, 2 H,
NH), 7.8 (d, J HH ) 8.2 Hz, 4 H, Ar H), 7.2 (d, J HH ) 8.2 Hz, 8
H, Ar H), 6.8 (d, J HH ) 8.2 Hz, 4 H, Ar H), 2.4 (s, 6 H, CH3),
3
2.2 (s, 6 H, CH3), 1.5 (d, J HP ) 15 Hz, 36 H, CH3). 13C{1H}
The standard deviations on intensities were calculated in
NMR (CDCl3, 293 K): δ (ppm) 130.3 s [d, 1J CH ) 160 Hz], 129.0
2
term of statistics alone, while those on Fo were calculated as
1
1
s [d, J CH ) 161 Hz], 125.5 s [d, J CH ) 163 Hz], 124.2 s [d,
shown in Table S1.
1J CH ) 163 Hz], 141.3 s [s], 38.0 s [s], 30.5 s [q, J CH ) 148
1
All calculations were carried out by using the PC version of
the SHELX-97 programs.27 The scattering factors used, cor-
rected for the real and imaginary parts of the anomalous
dispersion, were taken from the literature.28
Str u ctu r al Stu dy of [P t2(µ-P Bu t2){µ,η2-P (Bu t2)C(dNAr )}-
(CNAr )2] (8). The structure was solved by direct and Patterson
methods.
1
Hz], 21.5 (2 overlapping s) [q, J CH ) 129 Hz] (features from
the proton-coupled spectrum are shown in brackets). 195Pt{1H}
1
2
NMR (CDCl3, 293 K): δ (ppm) - 4496 (dd, J PtP ) 1820, J PtP
) - 260 Hz) [3J PtH ) 128 Hz from the proton-coupled
spectrum]. IR (Nujol, KBr): 2147 (νCN), 1262, 1156, 1033, 637
(uncoordinated triflate) cm-1
.
Cr ysta llogr a p h y. Air-stable crystals of [Pt2(µ-PBut ){µ,η2-
2
P(But )C(dNAr)}(CNAr)2] (8) were obtained by recrystalliza-
2
(25) SAINT: SAX Area Detector Integration: Siemens Analytical
Instrumentation, 1996.
(26) Sheldrick, G. M. SADABS, Universita¨t Go¨ttingen, Go¨ttingen,
Germany (to be submitted for publication).
(27) Sheldrick, G. M. SHELX-97: Structure Solution and Refine-
ment Package; Universita¨t Go¨ttingen, Go¨ttingen, Germany, 1997.
(28) International Tables for X-ray Crystallography; Wilson, A. J .
C. Ed.; Kluwer Academic: Dordrecht, The Netherlands. 1992; Vol. C.
tion from toluene-hexane mixtures.
Crystals of [Pt{µ,η2-P(But )C(NHAr)}(CNAr)]2(CF3SO3)2 (11),
2
suitable for X-ray diffraction, were obtained by crystallization
from CH2Cl2/Et2O and are air stable.
(24) J ohnstone, D. H.; Shriver, D. F. Inorg. Chem. 1993, 32, 1045.

Isonitrile Insertion into a Phosphido Bridge
Organometallics, Vol. 19, No. 22, 2000 4595
Data were refined by full-matrix least squares,27 minimizing
Upon convergence (see Table S1) the final Fourier difference
map showed no significant peaks.
the function ∑w(Fo - (1/k)Fc2)2. Anisotropic displacement
2
parameters were used for all atoms, while the contribution of
the hydrogen atoms, in their calculated positions (C-H ) 0.95
Å, B(H) ) 1.5[B(Cbonded)] Å2), was included in the refinement
using a riding model.
No extinction correction was deemed necessary. Upon
convergence (see Table S1) the final Fourier difference map
showed no significant peaks.
Ack n ow led gm en t. The Consiglio Nazionale delle
Ricerche (CNR) and MURST, Programmi di Interesse
Nazionale, 1998-9, are gratefully acknowledged for
financial support. A.A. and F.E. wish to thank the
Vigoni program for partial support.
Str u ctu r a l Stu d y of [P t{µ,η2-P (Bu t2)C(NHAr )}(CNAr )]2-
(CF 3SO3)2 (11). The structure was solved and refined as above
using anisotropic displacement parameters for all atoms. The
contribution of the hydrogen atoms, in their calculated posi-
tions (C-H ) 0.95 Å, B(H) ) 1.5[B(Cbonded)] Å2), was included
in the refinement using a riding model. No extinction correc-
tion was deemed necessary.
As can be seen from the large values of their atomic
displacements, the triflate counterions are disordered and their
unconstrained refinement led to unacceptable geometries.
Therefore, a model was constructed using the strongest peaks
of a difference Fourier map and constrained to retain a
tetrahedral geometry (around the carbon and sulfur atoms)
but allowing the C-F and S-O distances to vary.
Su p p or tin g In for m a tion Ava ila ble: Text giving experi-
mental details and a full listing of crystallographic data for
compounds 8 and 11, including tables of positional and
isotropic equivalent displacement parameters, calculated posi-
tions of the hydrogen atoms, anisotropic displacement param-
eters, bond distances and angles, and ORTEP figures showing
the full numbering schemes, and experimental and calculated
31P{1H} and 195Pt{1H} NMR spectra of complex 9. This
material is available free of charge via the Internet at
http://pubs.acs.org.
OM000461T