Contrasting thermal and photochemical intramolecular coupling in alkynylphosphine platinum(II) complexes

Article abstract of DOI:10.1021/om060342z

The thermal and photochemical transformations of a series of alkynylphosphine platinum(II) complexes are described. Compounds [Pt](PPh ₂C≡CR)₂ ([Pt] = cis-Pt(C₆F ₅)₂, R = Ph, Tol) rearrange thermally to generate naphthalene-based diphenylphosphine complexes (1a, 1b) containing the fragment {C₁₀H₅-1-Ph-2,3-κPP′(PPh₂) ₂} or {7-CH₃-C₁₀H₄-1-Tol-2,3- κPP′(PPh₂)₂}, formed by intramolecular coupling of two adjacent PPh₂C≡CR ligands. By contrast, irradiation of these alkynylphosphine derivatives in toluene results in the formation of a mixture of 1a/1b and the 1,2-diphosphino-alk-1-ene complexes [Pt]{PPh₂C-(Ph)=C(R)PPh(C≡CR)} (R = Ph, 2a; Tol, 2b) in a final ratio of 60:40. However, irradiation of the mixed alkynylphosphine derivatives [Pt](PPh₂C≡CR)(PPh₂C≡Ct-Bu) gives selectively [Pt]{Ph₂PC(Ph)= C(R)PPh(C≡Ct-Bu)} (R = Ph, 3a; Tol, 3b; t-Bu, 3c) as result of a P-C(Ph) activation of a tert-butylalkynylphosphine, PPh ₂C≡Ct-Bu. Under thermolysis, bis(tert-butyl)alkynyl derivatives produce no evidence of any cyclization product, but the mixed alkynylphosphine derivatives [Pt](PPh₂C≡CR)-(PPh₂C≡Ct-Bu) evolve giving small amounts of 1a/1b and trans-[Pt(C₆F ₅)₂(PPh₂C≡Ct-Bu)₂], 4. Under photolytic conditions, the diynyl phosphine derivatives [Pt](PPh ₂Ca≡CC₆H₄C≡CR)₂ (R = Ph, t-Bu) rearrange directly to the naphthalene complexes [Pt]{7-C≡CR-C ₁₀H₄-1-(C₆H₄-pC≡CR)-2,3- κPP′(PPh₂)₂} (R = Ph, 5a; t-Bu, 5c), resulting from the intramolecular coupling of the two inner alkynyl fragments, with no observable intermediates. Finally, site-selective activation takes place by photochemical or thermal treatment of [Pt](PPh₂C≡CPh)(PPh ₂H), 6. Thus, while under photochemical conditions complex 6 yields selectively [Pt]{Ph₂PC(Ph)=C(Ph)PPhH}, 7, by a ligand rearrangement coupling process involving activation of a P-C(Ph) bond, the regioisomer [Pt]{Ph₂PC(H)=C(Ph)PPh₂}, 8, is generated by a thermal activation of the P-H bond.

Full text of DOI:10.1021/om060342z

3926
Organometallics 2006, 25, 3926-3934
Contrasting Thermal and Photochemical Intramolecular Coupling in
Alkynylphosphine Platinum(II) Complexes
Ana Garc´ıa, Julio Go´mez, Elena Lalinde,* and M. Teresa Moreno
Departamento de Qu´ımica, Grupo de S´ıntesis Qu´ımica de La Rioja, UA-CSIC, UniVersidad de La Rioja,
26006, Logron˜o, Spain
ReceiVed April 18, 2006
The thermal and photochemical transformations of a series of alkynylphosphine platinum(II) complexes
are described. Compounds [Pt](PPh2CtCR)2 ([Pt] ) cis-Pt(C6F5)2, R ) Ph, Tol) rearrange thermally to
generate naphthalene-based diphenylphosphine complexes (1a, 1b) containing the fragment {C10H5-1-
Ph-2,3-κPP′(PPh2)2} or {7-CH3-C10H4-1-Tol-2,3-κPP′(PPh2)2}, formed by intramolecular coupling of two
adjacent PPh2CtCR ligands. By contrast, irradiation of these alkynylphosphine derivatives in toluene
results in the formation of a mixture of 1a/1b and the 1,2-diphosphino-alk-1-ene complexes [Pt]{PPh2C-
(Ph)dC(R)PPh(CtCR)} (R ) Ph, 2a; Tol, 2b) in a final ratio of 60:40. However, irradiation of the
mixed alkynylphosphine derivatives [Pt](PPh2CtCR)(PPh2CtCt-Bu) gives selectively [Pt]{Ph2PC(Ph)d
C(R)PPh(CtCt-Bu)} (R ) Ph, 3a; Tol, 3b; t-Bu, 3c) as result of a P-C(Ph) activation of a
tert-butylalkynylphosphine, PPh2CtCt-Bu. Under thermolysis, bis(tert-butyl)alkynyl derivatives produce
no evidence of any cyclization product, but the mixed alkynylphosphine derivatives [Pt](PPh2CtCR)-
(PPh2CtCt-Bu) evolve giving small amounts of 1a/1b and trans-[Pt(C6F5)2(PPh2CtCt-Bu)2], 4. Under
photolytic conditions, the diynyl phosphine derivatives [Pt](PPh2CtCC6H4CtCR)2 (R ) Ph, t-Bu)
rearrange directly to the naphthalene complexes [Pt]{7-CtCR-C10H4-1-(C6H4-pCtCR)-2,3-κPP′(PPh2)2}
(R ) Ph, 5a; t-Bu, 5c), resulting from the intramolecular coupling of the two inner alkynyl fragments,
with no observable intermediates. Finally, site-selective activation takes place by photochemical or thermal
treatment of [Pt](PPh2CtCPh)(PPh2H), 6. Thus, while under photochemical conditions complex 6 yields
selectively [Pt]{Ph2PC(Ph)dC(Ph)PPhH}, 7, by a ligand rearrangement coupling process involving
activation of a P-C(Ph) bond, the regioisomer [Pt]{Ph2PC(H)dC(Ph)PPh2}, 8, is generated by a thermal
activation of the P-H bond.
metal complexes have been designed. The cleavage of the
phosphorus-carbon bond to generate bridging diphenylphos-
phido and alkynyl groups has been observed by pyrolizing metal
carbonyl clusters.15-21 The cyclization reactions are of partic-
ular interest for the work presented here. Several years ago,
Carty et al. showed the thermal intramolecular coupling of the
two alkynyl moieties located in close proximity in cis-[PtX2-
(PPh2CtCR)2] to form substituted naphthalenes.22,23 One of the
parameters that seems to play a role in this reaction is the
separation between the acetylenic carbon atoms (commonly
referred to as the CR-CR distance). Recently, we have demon-
strated4,6,9 the formation of novel coordinated naphthalene
diphosphine ligands ({C10H4-1-C6F5-4-Ph-2,3-κPP′(PPh2)2} (L1)
and {7-CH3-C10H3-1-C6F5-4-Tol-2,3-κPP′(PPh2)2} (L2)) facili-
Introduction
Coordination chemistry of alkynylphosphines has long been
investigated. The η2-binding at the triple bond and coordination
of metal ions at the P donor allow the straightforward formation
of a variety of polynuclear species.1-14 Several strategies of
reactivity of alkynylphosphines coordinated via phosphorus to
* Corresponding author. E-mail: elena.lalinde@dq.unirioja.es.
(1) Went, M. J. Polyhedron 1995, 14, 465, and references therein.
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10.1021/om060342z CCC: $33.50 © 2006 American Chemical Society
Publication on Web 07/01/2006

Intramolecular Coupling in Alkynylphosphine Pt(II) Complexes
Organometallics, Vol. 25, No. 16, 2006 3927
Scheme 1
Scheme 2
control the cyclization process involving alkynylphosphine lig-
ands, we have examined the behavior of several pentafluophenyl
mononuclear platinum complexes bearing different alkynylphos-
phines, [Pt](PPh2CtCR)2 (R ) Ph, Tol), [Pt](PPh2CtCR)-
(PPh2CtCt-Bu), [Pt](PPh2CtCC6H4CtCR)2 (R ) Ph, t-Bu),
and [Pt](PPh2CtCPh)(PPh2H), under thermal and photochemi-
cal conditions, which have been shown to promote cyclization
reactions in all cases.
tated by complexation of the “Pt(C6F5)2” fragment to platinum
and palladium precursors containing at least two alkynylphos-
phine ligands (see Scheme 1). The formation of the ligands takes
place through initial µ-2,3-bis(diphenylphosphino)-1,3-butadien-
1-yl binuclear complexes {µ-C(R)(C6F5)dC(PPh2)C(PPh2)d
C(R)} formed by successive insertion of both PPh2CtCR
ligands into a Pt-C6F5 bond, which evolve through a formal
4-1 migration to analogous {µ-C(C6F5)dC(PPh2)C(PPh2)d
C(R)2} isomers and finally to 1-pentafluorophenyl-2,3-bis-
(diphenylphosphine)naphthalene derivatives.
In the context of this chemistry we note the Bergman-
cyclization processes of bis(phosphino)enediynes upon com-
plexation to metal ions. The thermal reactivity of such systems
is elegantly modulated by the adequate choice of the metal ion
geometry, indicating that both conformational and electronic
effects play a prominent role in the final reactivity of the
enediyne ligands.24-26 More recently, two examples of cycload-
dition reactions of rigid diyne-based bis(diphenylphosphino)
complexes to give strained macrocyclic ring systems have been
also described.12,27 Apart from thermal effects or metal ion
complexation, other cyclization strategies have been employed
for the activation of alkynylphosphines. Examples of these are
the insertion of the alkynyl functionality into a metal-carbon
bond4,6,9,28-33 or reactions with nucleophilic or electrophilic
substrates.34-39 To get a better insight into the parameters that
Results and Discussion
Carty and co-workers reported that pyrolysis of a solid sam-
ple of [Pt](PPh2CtCPh)2 at 210 °C for 2.5 h afforded the bis-
(diphenylphosphine)naphthalene species [Pt]{C10H5-1-Ph-2,3-
κPP′(PPh2)2}, 1a, by the intramolecular coupling reaction of
two coordinated cis-alkynylphosphine ligands.22 The ligand has
been suggested to be formed via a biradical intermediate or a
concerted [2+2+2] cycloaddition to form a common intermedi-
ate followed by a 1,3-hydrogen shift.22 Likewise, we have found
that thermal treatment (∼220 °C, 1 h) of the analogous
tolylalkynylphosphine complex [Pt](PPh2CtCTol)2 gives the
related derivative [Pt]{7-CH3-C10H4-1-Tol-2,3-κPP′(PPh2)2}, 1b,
as the only phosphorus-containing final species (Scheme 2). The
formation of the chelating bis(diphenylphosphine)naphthalene
ligands, characterized by X-ray in 1a,22 is inferred by the
presence of two relatively close and characteristic, deshielded
31P{1H} NMR resonances (δ 46.53, 41.06, 1a; 46.17, 40.24,
1b) with a slightly smaller 1JPt-P coupling constant for the high-
energy signal (2267/2322 Hz, 1a; 2242/2309 Hz, 1b) and both
values, as expected, smaller than in the corresponding starting
materials (2400 Hz, R ) Ph; 2407 Hz, R ) Tol). The 19F NMR
spectra confirm the existence of two different sets of C6F5
ligands, and in the proton spectrum of 1b, two methyl reso-
nances at 2.29 and 2.24 ppm are in agreement with the formation
of the {7-CH3-C10H4-1-Tol-2,3-κPP′(PPh2)2} ligand.
(24) Coalter, N. L.; Concolino, T. E.; Streib, W. E.; Hughes, C. G.;
Rheingold, A. L.; Zaleski, J. M. J. Am. Chem. Soc. 2000, 122, 3112.
(25) Basak, A.; Mandal, S.; Bag, S. S. Chem. ReV. 2003, 103, 4077.
(26) Schmitt, E. W.; Huffman, J. C.; Zaleski, J. M. Chem. Commun.
2001, 167.
(27) Martin-Redondo, M.; Scoles, L.; Sterenberg, B. T.; Udachin, K.
A.; Carty, A. J. J. Am. Chem. Soc. 2005, 127, 5038.
(28) Dupuis, L.; Pirio, N.; Meunier, P.; Igau, A.; Donnadieu, D.; Mayoral,
J.-P. Angew. Chem., Int. Ed. Engl. 1997, 36, 987.
(29) Rosa, P.; Le Floch, P.; Ricard, L.; Mathey, F. J. Am. Chem. Soc.
1997, 119, 9417.
(30) Miquel, Y.; Igau, A.; Donnadieu, B.; Majoral, J. P.; Dupuis, L.;
Pirio, N.; Meunier, P. Chem. Commun. 1997, 279.
Under photolytic conditions, these cis-bis(alkynylphosphine)-
platinum(II) complexes simultaneously afford not only the
diphosphinenaphthalene derivatives 1 but also new diphosphine
complexes 2, resulting from an easy P-C(Ph) activation in one
PPh2CtCR ligand and its formal final 2,1-addition to the triple
bond of the second PPh2CtCR group (Scheme 2). Thus,
photochemical reaction of cis-[Pt(C6F5)2(PPh2CtCR)2] (R )
Ph, Tol) in toluene solutions for 1 h at room temperature using
(31) Bennett, M. A.; Cobley, C. J.; Rae, A. D.; Wenger, E.; Willis, A.
C. Organometallics 2000, 19, 1522.
(32) Edwards, A. J.; Macgregor, S. A.; Rae, A. D.; Wenger, E.; Willis,
A. C. Organometallics 2001, 20, 2864.
(33) El Harouch, Y.; Cadierno, V.; Igau, A.; Donnadieu, B.; Majoral, J.
P. J. Organomet. Chem. 2004, 689, 953.
(34) Bennett, M. A.; Castro, J.; Edwards, A. J.; Kopp, M. R.; Wenger,
E.; Willis, A. C. Organometallics 2001, 20, 980.
(35) Bennett, M. A.; Kwan, L.; Rae, A. D.; Wenger, E.; Willis, A. C. J.
Chem. Soc., Dalton Trans. 2002, 226.
(36) Liu, X.; Mok, K. F.; Leung, P. H. Organometallics 2001, 20, 3918.
(37) Liu, X.; Ong, T. K. W.; Selvaratnam, S.; Vittal, J. J.; White, A. J.
P.; Williams, D. J.; Leung, P. H. J. Organomet. Chem. 2002, 643, 4.
(38) Carty, A. J.; Jacobson, S.; Simpson, R. T.; Taylor, N. J. J. Am.
Chem. Soc. 1975, 97, 7254.
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Commun. 1974, 668.

3928 Organometallics, Vol. 25, No. 16, 2006
Garc´ıa et al.
Table 1. Selected Bond Distances (Å) and Angles (deg) for
Scheme 3
trans-[Pt(C6F5)2(PPh2CtCt-Bu)2], 4a
Pt(1)-C(19)
Pt(1)-P(1)
2.063(3)
2.2986(9)
P(1)-C(1)
C(1)-C(2)
1.747(4)
1.199(4)
C(19)-Pt(1)-P(1)
C(19a)-Pt(1)-P(1)
P(1)-Pt(1)-P(1a)
90.06(9)
89.94(9)
180.00(3)
P(1)-C(1)-C(2)
C(1)-C(2)-C(3)
Pt(1)-P(1)-C(1)
175.2(3)
179.7(4)
114.54(11)
a Symmetry transformations used to generate equivalent atoms are #1
-x+2, -y, -z.
Table 2. Selected Bond Distances (Å) and Angles (deg) for
cis-[Pt(C6F5)2{Ph2PC(Ph)dC(Ph)PPh(CtCt-Bu)}], 3a
Pt(1)-C(39)
Pt(1)-C(45)
P(1)-C(1)
P(2)-C(2)
2.065(9)
2.083(7)
1.830(8)
1.847(7)
Pt(1)-P(1)
Pt(1)-P(2)
C(1)-C(2)
C(27)-C(28)
2.2527(18)
2.268(2)
1.333(10)
1.167(12)
also monitored by NMR spectroscopy, and transformation to
[Pt]{Ph2PC(Ph)dC(R)PPh(CtCt-Bu)} (R ) Ph, 3a; Tol, 3b)
(Scheme 3) was only quantitatively observed with the mixed
aryl/tert-butylalkynylphosphine derivatives. As was expected,
the related [Pt](PPh2CtCt-Bu)2 gives, by photolysis, the cor-
responding complex [Pt]{Ph2PC(Ph)dC(t-Bu)PPh(CtCt-Bu)},
3c. The site-selective activation of P-C(phenyl) bonds with
respect to the P-CtCR bonds in the ligands PPh2CtCR
(R ) Ph, 2a; Tol, 2b; t-Bu, 3) is in contrast with pre-
vious observations, according to which the bond cleavage
in phosphines follows the order P-C(sp) > P-C(sp2) >
P-C(sp3).40,41
C(39)-Pt(1)-C(45)
P(1)-Pt(1)-P(2)
C(1)-P(1)-Pt(1)
C(2)-P(2)-Pt(1)
C(21)-C(1)-P(1)
C(3)-C(2)-P(2)
90.9(3)
C(39)-Pt(1)-P(1)
C(45)-Pt(1)-P(2)
C(2)-C(1)-P(1)
C(1)-C(2)-P(2)
C(28)-C(27)-P(1)
C(27)-C(28)-C(29)
92.7(2)
91.1(2)
118.7(5)
117.5(6)
168.3(8)
177.1(10)
85.42(7)
109.3(2)
108.9(2)
116.6(5)
120.2(5)
Table 3. Selected Bond Distances (Å) and Angles (deg) for
cis-[Pt(C6F5)2{Ph2PC(Ph)dC(Ph)PPhH}]‚CHCl3, 7‚CHCl3
Pt(1)-C(33)
Pt(1)-C(39)
P(1)-C(1)
P(2)-C(2)
2.092(6)
2.074(5)
1.826(6)
1.840(6)
Pt(1)-P(1)
Pt(1)-P(2)
C(1)-C(2)
P(1)-H(1)
2.2419(14)
2.2751(15)
1.345(8)
0.9800
The X-ray molecular structure of 3a (see below) indicates
that the photochemical reaction produces regiospecifically 1,2-
diphosphinoalk-1-ene complexes, involving a formal 2,1-
addition of a P-C(Ph) bond in one phosphine through the
CtCR of the other phosphine. The 31P{1H} NMR spectra of
complexes 3a-c show two broad, well-separated singlet
resonances (δ 62.97-58.42/33.12-27.33) strongly deshielded
with respect to the starting material, arising from two non-
equivalent phosphorus atoms in the final five-membered chelate
ring. The low-frequency resonances are tentatively assigned to
the phosphorus atom of the PPhCtCt-Bu group, whereas the
highly deshielded signals are therefore attributed to the PPh2
fragment of the diphenylphosphine alkene ligand. This assign-
ment is in accord with the chemical shifts of phosphines such
as PPh3 (δ ≈ -6 ppm) and PPh2CtCt-Bu (δ -34.24).31 At
low temperature (223 K), the 19F NMR spectra display two
different sets of rigid C6F5 groups (AFMRX systems), confirm-
ing that the platinum coordination plane is not a symmetry plane.
Upon heating to 293 K, the pattern in the ortho-fluorine region
indicates that one of the C6F5 groups is still rigid on the NMR
time scale. Their IR spectra exhibit two characteristic ν(CtC)
absorptions in the range 2167-2219 cm-1 due to the uncoor-
dinated CtCt-Bu fragments.
C(33)-Pt(1)-C(39)
P(1)-Pt(1)-P(2)
C(1)-P(1)-Pt(1)
C(2)-P(2)-Pt(1)
C(3)-C(1)-P(1)
87.5(2)
85.44(5)
109.14(18)
108.18(19)
116.9(4)
C(33)-Pt(1)-P(1)
C(39)-Pt(1)-P(2)
C(2)-C(1)-P(1)
C(1)-C(2)-P(2)
C(9)-C(2)-P(2)
91.35(17)
96.01(18)
118.0(4)
117.8(4)
121.8(4)
Table 4. Selected Bond Distances (Å) and Angles (deg) for
cis-[Pt(C6F5)2{Ph2PC(H)dC(Ph)PPh2}], 8
Pt(1)-C(33)
Pt(1)-C(39)
P(1)-C(1)
P(2)-C(2)
2.075(4)
2.094(5)
1.806(5)
1.854(5)
Pt(1)-P(1)
Pt(1)-P(2)
C(1)-C(2)
C(1)-H(1)
2.2608(13)
2.2756(12)
1.324(6)
0.9300
C(33)-Pt(1)-C(39)
P(1)-Pt(1)-P(2)
C(1)-P(1)-Pt(1)
C(2)-P(2)-Pt(1)
H(1)-C(1)-P(1)
88.98(18)
C(33)-Pt(1)-P(1)
C(39)-Pt(1)-P(2)
C(2)-C(1)-P(1)
C(1)-C(2)-P(2)
C(1)-C(2)-C(3)
91.43(13)
93.94(14)
121.0(4)
116.3(4)
122.2(4)
85.66(4)
107.21(17)
107.74(15)
119.5
Table 5. Control of the Formation of 1a and 2a by 31P{1H}
NMR
time (min)
cis-[Pt(C6F5)2(PPh2CtCPh)2]
1a
2a
5
25
70
43
15
6
20
37
55
61
58
10
20
30
33
39
45
60a
75a
≈3
The 31P{1H} NMR spectra of complexes 3 and 1 allow us
to assign the corresponding signals for compounds 2 in the
final mixtures 1/2 (60:40) obtained from photolysis of [Pt]-
(PPh2CtCR)2 (R ) Ph, Tol) (see Experimental Section). As
described for 3a-c, complexes 2a and 2b show two separated
signals (δP 58.92/28.38, 2a; 58.50/28.48, 2b) versus the close
signals assigned to naphthalene complexes 1 (46.50/41.03, 1a;
46.18/40.25, 1b).
The thermolysis reactions of the tert-butylalkynylphosphine
complexes [Pt](PPh2CtCR)(PPh2CtCt-Bu) (R ) Ph, Tol,
t-Bu) were also examined (Scheme 3). Surprisingly, no reaction
was observed with the sterically bulky bis(tert-butylalky-
a Small signals at δ 54.9, 43.1, and 18.1 were also observed.
a 400 W Hg lamp results in the formation of a mixture of the
naphthalene complexes 1a and 1b and new platinum complexes
2a and 2b (Scheme 2). Monitoring these reactions over a period
of time (Table 5) indicated the parallel formation of both species
1a/2a, 1b/2b resulting in a final 60:40 ratio, even with longer
reaction times. All attempts to separate both types of complexes
have been unsuccessful. The formulation of 2a and 2b as 1,2-
diarylalkene-1,2-diphosphine complexes is clearly supported by
the photochemical reaction of the related mixed tert-butylalky-
nylphosphine species [Pt](PPh2CtCR)(PPh2CtCt-Bu) (R ) Ph,
Tol) in toluene. With these precursors the formation of 1-t-Bu-
naphthalene complexes was not observed. The reactions were
(40) Carty, A. J. Pure Appl. Chem. 1982, 54, 113, and references therein.
(41) Tschan, M. J. L.; Che´rioux, F.; Karmazin-Brelot, L.; Su¨ss-Fink, G.
Organometallics 2005, 24, 1974.

Intramolecular Coupling in Alkynylphosphine Pt(II) Complexes
Organometallics, Vol. 25, No. 16, 2006 3929
Scheme 4
[Pt]{7-CtCR-C10H4-1-(C6H4-pCtCR)-2,3-κPP′(PPh2)2} (R )
Ph, 5a; t-Bu, 5c), resulting from the intramolecular coupling of
the two inner alkynyl fragments (eq 1). The formation of these
Figure 1. Molecular structure of trans-[Pt(C6F5)2(PPh2CtCt-Bu)2],
4. Ellipsoids are drawn at the 50% probability level.
nylphosphine) complex. However, when the mixed aryl/tert-
butylphosphine derivatives were heated at their melting point
for 2 h, the 31P{1H} NMR spectrum of the final brown oily
residue obtained showed the formation of a mixture of com-
plexes, which contain (see Experimental Section) small amounts
of the corresponding precursors, the naphthalene species 1a or
1b and, surprisingly, the trans-derivative trans-[Pt(C6F5)2-
(PPh2CtCt-Bu)2], 4, common to both reactions. Crystallization
of these mixtures at low temperature generates colorless crystals
of 4. Figure 1 shows the X-ray structure of complex 4, which
contains two trans-oriented C6F5 and two tert-butylethynylphos-
phine ligands. This complex can be alternatively prepared in
high yield by simple displacement of the tetrahydrothiophene
ligands (tht) in trans-[Pt(C6F5)2(tht)2] by PPh2CtCt-Bu (see
Experimental Section). We recently reported the isomeric cis-
[Pt(C6F5)2(PPh2CtCt-Bu)2] (δP -8.79; 1JP-Pt ) 2426 Hz).4 The
trans derivative 4 is characterized by a single resonance at δ
species is inferred by the similarity of their spectroscopic data
with those of the products 1a and 1b. The most characteristic
feature appears in their 31P{1H} NMR spectra, which exhibit
two close doublets in the region of 40-46 ppm, the P-P
coupling constants being ca. 9 Hz, with the corresponding
platinum satellites (1JPt-P ) 2310-2250 Hz). Their IR spectra
showed, in each case, two ν(CtC) absorptions (range 2219-
2173 cm-1) due to the uncoordinated alkyne fragments, and
two different alkyne moieties are inferred from their 13C{1H}
NMR spectra. Thus, four singlet signals (δ 92.0, 90.1, 88.6,
88.4, 5a; 101.6, 99.3, 78.5, 78.1, 5b) corresponding to both
alkyne Câ and both CR carbon resonances are seen, contrasting
with the typical AXX′ pattern for the inner (P-CRtCâ-) alkyne
carbons of the precursors [Pt](PPh2CtC-C6H4-CtCR)2 (R
) Ph, t-Bu) [81.9 (CR, 1+3JC-P 101.3 Hz, 2JCR-Pt 17 Hz); 107.3
1
-7.60 with a JP-Pt of 2854 Hz, in agreement with the higher
trans influence of PPh2CtCt-Bu relative to the C6F5 ligand. It
should be noted that trans-configured mononuclear platinum
complexes containing alkynylphosphines had not been previ-
ously reported, probably due to the fact that the precursors
previously employed (K2PtCl412,42-44 or [PtR2(cod)]3,7) usually
generate final cis-derivatives. The structural parameters of the
trans complex 4 are unexceptional (Table 1), with structural
data comparable to those of the related palladium complexes,
trans-[PdX2(PPh2CtCPh)2] (X ) Br, I).12 The two P-CtC
units exhibit a transoid arrangement with a torsion angle
CR-P-Pt-P-CR of 180° and the C6F5 rings are coplanar,
forming a dihedral angle with the platinum plane of 85.56°.
The details of alkynyl fragments (P-CR-Câ 175.2(3)°,
CR-Câ-Cγ 179.7(4)°, CRtCâ 1.199(4) Å) are typical of
P-coordinated alkynylphosphine ligands.
2+4
1+3
(Câ,
J
15 Hz) R ) Ph; 81.3 (CR,
J
102 Hz, CR);
C-P
C-P
2+4
107.5 (Câ,
J
15.1 Hz) R ) t-Bu]. As expected, the 19F
C-P
NMR spectra show two sets (AA′MXX′ systems) of C6F5 signals
in accordance with the presence of two nonequivalent C6F5
groups.
Despite several attempts to grow crystals for X-ray analysis
of 5a or 5c, no crystals were obtained. In an attempt to isolate
one of the free phosphines, complex 5c in DMSO was treated
with an excess of KCN for 24 h. The 31P{1H} NMR spectrum
of the residue, obtained after usual workup, exhibits an AB spin
system (δA -6.14, δB -10.52, JAB ) 155 Hz) in good agree-
ment with the formation of free ligand. However, all attempts
to obtain crystals from the ligand were also unsuccessful.
Finally, we present the results of the thermal and photo-
chemical reactions of a platinum(II) complex bearing one
alkynylphosphine and a diphenylphosphine ligand, [Pt](PPh2Ct
CPh)(PPh2H), 6 (Scheme 4). This kind of system may be of
interest, taking into account the precedents on P-H activation
by addition of a secondary phosphine to a coordinated alkynyl
As an extension of our investigation, we studied the thermal
and photochemical reactions of the P-coordinated diynylphos-
phine Pt(II) mononuclear complexes [Pt](PPh2CtC-C6H4-
CtCR)2 (R ) Ph, t-Bu),10 to compare, in particular, the
reactivity of inner and outer units. Unfortunately, no change
was observed with these precursors after heating for 6 h at 250
°C. However, photolysis of toluene solutions of these com-
plexes for 45 min cleanly afforded the new naphthalene products
(42) Simpson, R. T.; Carty, A. J. J. Coord. Chem. 1973, 2, 207.
(43) Carty, A. J.; Johnson, D. K.; Jacobson, S. J. Am. Chem. Soc. 1979,
101, 5612.
(44) Carty, A. J.; Efrati, A. Can. J. Chem. 1969, 47, 2573.

3930 Organometallics, Vol. 25, No. 16, 2006
Garc´ıa et al.
phosphine. Along this line, several years ago Carty et al. showed
that the addition of secondary phosphines to coordinated
alkynylphosphines in metal complexes (Ni, Pd, Pt) yields
stereospecifically unsymmetrical diphosphine (cis-1,2-diphos-
phinoalk-1-ene) complexes.22,43 We have recently reported the
synthesis of the cationic related complex [Pt(bzq)(PPh2CtCPh)-
(PPh2H)]ClO4 (bzq ) benzoquinolate)45 and its evolution, even
at low temperature, to a mixture of isomers of 1,2-diphosphi-
noalk-1-ene complex [Pt(bzq)(PPh2C(Ph)dC(H)PPh2)]ClO4,
formally generated by addition of a P-H bond to the coordi-
nated PPh2CtCPh ligand.
Complex [Pt](PPh2CtCPh)(PPh2H), 6, was synthesized by
displacement of the tetrahydrothiophene labile ligand on
[Pt](PPh2CtCPh)(tht)7 by diphenylphosphine and characterized
by usual analytical and spectroscopic means. In particular, 6
shows two characteristic absorptions in its IR spectrum due to
ν(P-H) (2358 cm-1) and to ν(CtC) (2177 cm-1) vibrations,
and its 31P{1H} spectrum exhibits two broad doublets flanked
by platinum satellites (δ -5.56, 1JPt-P ) 2223 Hz; -7.39 1JPt-P
) 2338 Hz, JP-P ≈ 10 Hz). The high-field signal (δ -5.56),
which splits into a doublet due to the P-H coupling (378 Hz)
under off conditions, is attributed to the phosphorus atom of
the PPh2H ligand, whereas the signal at -7.39 is assigned to
the PPh2CtCPh ligand. The resonance corresponding to the
CR alkyne carbon is found as a doublet of doublets at lower
frequency than the Câ atom (δ CR 78.1 vs Câ 108.6) and shifted
with respect to that of free PPh2CtCPh (δ CR 86.5/Câ 109.4).
The resulting shift difference (∆(δCâ - δCR)), which can be
related to the triple bond polarization,5,8,11,46 is, in this case,
30.5, which is similar to those observed in other alkynylphos-
phine neutral platinum complexes.3,6,7,9
The photochemical reaction of [Pt](PPh2CtCPh)(PPh2H), 6,
in toluene for 45 min, yields the asymmetric diphosphine
compound [Pt]{Ph2PC(Ph)dC(Ph)PPhH}, 7, in an intramolecu-
lar ligand coupling reaction that involves a very unusual and
selective activation of a P-C(Ph) bond in the PPh2H ligand
with formal final 2,1-addition to the triple bond of the PPh2Ct
CPh group. Activation of the P-C(Ph) bond is a well-known
process,41,47-50 but the observed site-selective activation in the
presence of the P-H bond is noteworthy because the chemistry
of secondary phosphines is usually dominated by the reactive
P-H bond.51-56 However, the behavior of 6 upon thermolysis
contrasts that of the photolysis. Thus, by heating the solid 6 at
∼175 °C for 1 h the isomeric chelating diphosphine compound
[Pt]{Ph2PC(H)dC(Ph)PPh2}, 8, is cleanly obtained. The induced
2,1-addition of the P-H bond to the alkynylphosphine ligand
is in accordance with the triple bond polarization of this group
Figure 2. Molecular structure of cis-[Pt(C6F5)2{Ph2PC(Ph)dC(Ph)-
PPh(CtCt-Bu)}], 3a. Ellipsoids are drawn at the 50% probability
level.
upon coordination to the platinum center (Pt-PPh2Cδ-
t
Cδ+Ph). This product 8 can also be alternatively generated in
high yield by treatment of a dichloromethane solution of
complex 6 with (NBu4)(acac) (Scheme 4). The molecular
structures of both derivatives (see below) unambiguously
confirm that they are regioisomers, a fact previously confirmed
by spectroscopic means. Thus, in their IR spectra both com-
plexes (7 and 8) show an absence of ν(CtC) absorptions, but
in complex 7 a weak absorption due to the ν(P-H) at 2365
cm-1 can be observed. The proton spectrum of complex 7 shows
the expected large doublet due to the P-H proton centered at
δ 6.60 (1JP-H ) 389 Hz) and flanked by platinum satellites
(2JPt-H ) 32.3 Hz), confirming that this proton is not re-
moved from the phosphorus. However, complex 8 exhibits, in
CD3COCD3, a broad doublet resonance at 7.92 ppm with
platinum satellites (3JPt-H ) 40 Hz), which is modified by
selective 31P decoupling, being therefore assigned to the unique
vinylic proton. Carty et al. assigned the doublet separation (10.4
Hz in 8) of the vinyl proton resonance in related systems to
2
3
| JP-H + JP-H|.43 Complex 7 exhibits two phosphorus reso-
nances with platinum satellites at δ 61.05 and 28.06, respec-
tively, in accordance with the formation of the five-membered
phosphinoplatinacycle.22,43,45,57,58 In the proton-coupled 31P
experiment, the high-field signal (δ 28.06) splits into a doublet
resonance by P-H coupling (1JP-H ) 389 Hz), being attributed
to the phosphorus atom of the unit PPhH. In agreement with
the formation of the chelating diphosphine {Ph2PC(H)dC(Ph)-
PPh2}, complex 8 also display two singlets at δ 61.07 and 38.98,
but under off conditions, only the downfield signal (δ 61.07)
splits into a doublet resonance by P-H coupling (3JP-H ≈ 55
Hz), being assigned to phosphorus trans to the vinylic proton.
The X-ray structures of 3a, 7, and 8 (Figures 2-4 and Tables
2-4) confirm the formation of unsymmetrical diphosphine
alkene ligands coordinated in a chelate-like fashion to the
platinum centers. The observed C(1)-C(2) alkene bond lengths
of 1.333(10) (3a), 1.345(8) (7), and 1.324(6) Å (8) are
comparable to those observed in related complexes.45,58,59 The
bond angles P(1)-C(1)-C(2) and C(1)-C(2)-P(2) are in the
(45) D´ıez, A.; Fornie´s, J.; Garc´ıa, A.; Lalinde, E.; Moreno, M. T. Inorg.
Chem. 2005, 44, 2443.
(46) Louattani, E.; LLedo´s, A.; Suades, J.; Alvarez-Larena, A.; Piniella,
J. F. Organometallics 1995, 14, 1053.
(47) Garrou, P. E. Chem. ReV. 1985, 3, 171.
(48) Shima, T.; Suzuki, H. Organometallics 2005, 24, 1703.
(49) Adams, R. D.; Captain, B.; Fu, W.; Smith, M. D. J. Organomet.
Chem. 2002, 651, 124.
(50) Xia, C. G.; Yang, K.; Bott, S. G.; Richmond, M. G. Organometallics
1996, 15, 4480.
(51) Levason, W. In The Chemistry of Organophosphorus Compounds;
Hartley, F. R., Ed.; Wiley: Chichester, England, 1990; Vol. 1, pp 567-
641.
(52) Zhuravel, M. A.; Grewal, N. S.; Glueck, D. S.; Lam, K. C.;
Rheingold, A. L. Organometallics 2000, 19, 2882.
(53) Kourkine, I. V.; Sargent, M. D.; Glueck, D. S. Organometallics
1998, 17, 125.
(54) Witch, D. K.; Kourkine, I. V.; Lew, B. M.; Nthenge, J. M.; Glueck,
D. S. J. Am. Chem. Soc. 1997, 119, 5039.
(55) Leoni, P. Organometallics 1993, 12, 2432.
(56) Alonso, E.; Fornie´s, J.; Fortun˜o, C.; Mart´ın, A.; Orpen, A. G.
Organometallics 2001, 20, 850.
(57) Garrou, P. E. Chem. ReV. 1981, 81, 229.
(58) Falvello, L. R.; Fornie´s, J.; Go´mez, J.; Lalinde, E.; Mart´ın, A.;
Moreno, M. T.; Sacrista´n, J. Chem. Eur. J. 1999, 5, 474.
(59) Taylor, N. J.; Jacobson, S.; Carty, A. J. Inorg. Chem. 1975, 14,
2648.

Intramolecular Coupling in Alkynylphosphine Pt(II) Complexes
Organometallics, Vol. 25, No. 16, 2006 3931
the new chelating diphosphine complexes [Pt]{PPh2C(Ph)d
C(R)PPh(CtCR)}, 2, generated by an unexpected selective
activation of a P-C(Ph) bond in one of the ligands with formal
2,1-addition to the CtC triple bond of the second phosphine.
Similar final 1,2-diphosphinoalk-1-ene complexes [Pt]{Ph2PC-
(Ph)dC(R)PPh(CtCt-Bu)}, 3, were formed by photolysis of
[Pt](PPh2CtCR)(PPh2CtCt-Bu) (R ) Ph, Tol, t-Bu). Under
thermal conditions, these later evolve (except for R ) t-Bu)
giving a mixture of species containing the trans-derivative trans-
[Pt(C6F5)2(PPh2CtCt-Bu)2], 4, along with trace amounts of 1
and the corresponding precursors. The mixed ligand complex
[Pt](PPh2CtCPh)(PPh2H), 6, selectively gives under photolysis
[Pt]{Ph2PC(Ph)dC(Ph)PPhH}, 7, by an activation of the
P-C(Ph) bond, while the expected isomer [Pt]{Ph2PC(H)d
C(Ph)PPh2}, 8, is formed under thermolysis or alternatively in
the presence of a base such as (NBu4)(acac).
Figure 3. Molecular structure of cis-[Pt(C6F5)2{Ph2PC(Ph)dC(Ph)-
PPhH}], 7. Ellipsoids are drawn at the 50% probability level.
Experimental Section
General Considerations. All reactions and manipulations were
carried out under an argon atmosphere using Schlenk techniques,
and distilled solvents were purified by known procedures. IR spectra
were obtained on a Perkin-Elmer FT-IR 1000 spectrometer using
Nujol mulls between polyethylene sheets. NMR spectra were
recorded on a Bruker ARX 300 spectrometer; chemical shifts are
reported in ppm relative to external standards (SiMe4, CFCl3, and
85% H3PO4), the temperature of the routine NMR being 293 K.
Elemental analyses were carried out with Carlo Erba EA1110
CHNS/O or Perkin-Elmer 2400 CHNS/O microanalyzers. Mass
spectra were recorded on a VG Autospec double-focusing mass
spectrometer operating in the FAB mode, on a HP-5989B mass
spectrometer using the ES techniques, and on a Microflex MALDI-
TOF Bruker spectrometer for MALDI-TOF spectra operating in
the linear and reflector modes using dithranol as matrix. The pre-
cursors cis-[Pt(C6F5)2(tht)(PPh2CtCPh)],7 cis-[Pt(C6F5)2(PPh2Ct
CR)2] (R ) t-Bu,4 Ph,4 Tol6), cis-[Pt(C6F5)2(PPh2CtCR)(PPh2Ct
Ct-Bu)] (R ) Ph, Tol),6 and cis-[Pt(C6F5)2(PPh2CtC-C6H4-Ct
CR)2] (R ) t-Bu, Ph)10 were prepared according to literature
methods. PPh2H was used as received.
Figure 4. Molecular structure of cis-[Pt(C6F5)2{Ph2PC(Ph)dC(H)-
PPh2}], 8. Ellipsoids are drawn at the 50% probability level.
116.3(4)-121.0(4)° range, close to the ideal value of 120° for
sp2 carbon atoms, the most marked difference between these
angles being found in 8. The planarity of the five-membered
chelate rings is reflected in the angle sum of 539.82° (3a),
538.56° (7), and 537.91° (8) with acute PPtP angles (85.42-
(7)°, 3a; 85.44(5)°, 7; 85.66(4)°, 8). The hydrogen atoms in 7
and 8 were located in the Fourier map with P-H and C-H
bond distances of 0.98 Å (7) and 0.93 Å (8), respectively.
General Procedure for Irradiation. The platinum mononuclear
complexes (∼0.20 mmol) were dissolved in ∼100 mL of deoxy-
genated toluene. The resulting colorless solutions were irradiated
at room temperature under an argon atmosphere through Pyrex glass
with a medium-pressure mercury lamp (400 W).
Synthesis of cis-[Pt(C6F5)2{C10H5-1-Ph-2,3-KPP′(PPh2)2}], 1a.22
A small quantity (∼0.05 g, 0.045 mmol) of solid cis-[Pt(C6F5)2-
(PPh2CtCPh)2] was heated at ∼220 °C in an oil bath for 1 h, giving
rise to a brown oil, the NMR data of which indicate the formation
1
of 1a in nearly quantitative yield. H NMR (δ, CDCl3): 8.43 (d,
Conclusions
1H, JH-H ) 9.5 Hz); 7.93 (d, 1H, JH-H ) 7.8 Hz); 7.63-6.78 (m,
27H); 6.35 (d, 1H, JH-H ) 7.3 Hz) (aromatics). 19F NMR (δ,
CDCl3): -116.6 (m, 3JPt-o-F ≈ 290 Hz, 2o-F); -117.3 (m, 3JPt-o-F
≈ 305 Hz, 2o-F); -162.8 (t, 1p-F); -162.9 (t, 1p-F); -164.5 (m,
2m-F); -164.9 (m, 2m-F). 31P{1H} NMR (δ, CDCl3): 46.53 (d,
In conclusion, we have examined the reactivity of alkynyl-
diphenylphosphine platinum(II) complexes under thermal or
photochemical conditions. [Pt](PPh2CtCR)2 (R ) Ph, Tol) were
found to rearrange by thermolysis to naphthalene-based diphen-
ylphosphine complexes [Pt]{C10H5-1-Ph-2,3-κPP′(PPh2)2}, 1a,
and [Pt]{7-CH3-C10H4-1-Tol-2,3-κPP′(PPh2)2}, 1b, presumably
through a [2+2+2] cycloaddition with subsequent 1,3-H shift
in a manner similar to that observed for dichloro Pt(II) deriv-
atives containing monophosphine22 and diphosphinoacetylene12
ligands. Similar naphthalene species [Pt]{7-CtCR-C10H4-1-
(C6H4-pCtCR)-2,3-κPP′(PPh2)2} (R ) Ph, 5a; t-Bu, 5c) were
also generated starting from the diynyl systems [Pt](PPh2Ct
CC6H4CtCR)2, but only under photolytical reaction conditions
(toluene, 45 min, eq 1). In contrast, the photolysis of the
monoalkynyl complexes [Pt](PPh2CtCR)2 (R ) Ph, Tol)
evolves with parallel formation of naphthalene species 1 and
2
1
1JPt-P ) 2267 Hz, JP-P ) 9.3 Hz); 41.06 (d, JPt-P ) 2322 Hz).
Synthesis of cis-[Pt(C6F5)2{7-CH3-C10H4-1-Tol-2,3-KPP′-
(PPh2)2}], 1b. Solid cis-[Pt(C6F5)2(PPh2CtCTol)2] (0.189 g, 0.168
mmol) was heated at ∼220 °C for 1 h, obtaining a brown oil. The
residue was treated with CH2Cl2 (10 mL) and charcoal and filtered
through Celite. Evaporation to small volume and addition of
n-hexane gave 1b as a brown solid (0.088 g, 47% yield). Anal.
Calcd for C54F10H34P2Pt (1129.88): C, 57.40; H, 3.03. Found: C,
57.32; H, 2.98. MS (MALDI-TOF (-): m/z 1128 [M - 2H]- 47%.
IR (cm-1): ν(CdC) 1605 (w); ν(C6F5)X-sens 790 (m), 780 (m). 1H
NMR (δ, CDCl3): 8.35 (d, 1H, JH-H ) 9.3 Hz); 7.82 (d, 1H, JH-H
) 8.3 Hz); 7.60-6.69 (m, 22H) (aromatics); 6.57 (d, JH-H ) 7.8
Hz); 6.22 (d, JH-H ) 7.8 Hz) (C6H4, Tol); 2.29 (s, 3H, CH3); 2.24

3932 Organometallics, Vol. 25, No. 16, 2006
Garc´ıa et al.
3
(s, 3H, CH3). 19F NMR (δ, CDCl3): -116.4 (m, JPt-o-F ≈ 310
(s); ν(CdC) 1605 (w); ν(C6F5)X-sens 789 (s), 780 (s). 1H NMR (δ,
CDCl3): 7.54-7.32 (m, 15H); 6.92 (m, 4H); 6.76 (m, 2H); 6.53
(d, 2H, JH-H ) 6.8 Hz); 6.28 (d, 2H, JH-H ) 7.1 Hz) (Ph); 1.24 (s,
9H, C(CH3)3). 19F NMR (δ, CDCl3): at 293 K, -116.7 (br, 1o-F);
3
Hz, 2o-F); -117.3 (m, JPt-o-F ≈ 310 Hz, 2o-F); -162.9 (t,
1p-F); -163.1 (t, 1p-F); -164.5 (m, 2m-F); -164.9 (m, 2m-F).
31P{1H} NMR (δ, CDCl3): 46.17 (d br, 1JPt-P ) 2242 Hz, 2JP-P
≈
1
3
8 Hz); 40.24 (d br, JPt-P ) 2309 Hz).
-117.8 (m, JPt-o-F ≈ 300 Hz, 2o-F); -118.3 (br, 1o-F); -162.2
(m, 2p-F); -164.7 (m, 3m-F); -165.2 (br, 1m-F); at 223 K, -116.9
Irradiation of cis-[Pt(C6F5)2(PPh2CtCPh)2]. Formation of cis-
[Pt(C6F5)2{C10H5-1-Ph-2,3-KPP′(PPh2)2}], 1a, and cis-[Pt(C6F5)2-
{PPh2C(Ph)dC(Ph)PPh(CtCPh)}], 2a. Irradiation of a colorless
solution of cis-[Pt(C6F5)2(PPh2CtCPh)2] (0.412 g, 0.374 mmol)
in toluene was followed by 31P{1H} NMR and 19F NMR spectros-
copy in CDCl3 at room temperature. The formation of a mixture
of 1a and 2a was observed, the approximate proportion of which,
in relation with time, is shown in Table 5. After 1 h and 15 min of
irradiation the resulting light yellow solution was evaporated to
small volume (∼2 mL) and treated with diethyl ether (∼10 mL),
causing the precipitation of a pale yellow solid, which was a mixture
of 1a and 2a (60:40) (0.322 g).
3
3
(m, JPt-o-F ≈ 305 Hz, 1o-F); -118.1 (m, JPt-o-F ≈ 295 Hz,
3
1o-F); -118.7 (m, JPt-o-F ≈ 295 Hz, 2o-F); -161.48, -161.51
(2p-F); -163.9 (m, 2m-F); -164.2 (m, 1m-F); -164.7 (m, 1m-F).
Between 243 and 253 K, the signal at -118.1 ppm and one of the
o-F at -118.7 ppm coalesce to one slightly shifted and centered at
ca. -118.1 ppm. 31P{1H} NMR (δ, CDCl3): 58.84 (s, JPt-P
)
1
1
2283 Hz); 27.33 (s, JPt-P ) 2371 Hz).
Data for 3b. Anal. Calcd for C51F10H36P2Pt (1095.87): C, 55.90;
H, 3.31. Found: C, 55.68; H, 3.00. MS (FAB+): m/z 929 [M -
C6F5]+ 18%; 762 [M - 2C6F5]+ 32%. MS (apci-): m/z 1095 [M]-
25%; 1018 [M - Ph]- 100%. IR (cm-1): ν(CtC) 2219 (m), 2176
1
(s); ν(CdC) 1600 (w); ν(C6F5)X-sens 790 (m), 781 (s). H NMR
If the solution was irradiated for a longer time (∼8 h), the
resulting pale yellow solid was a mixture of 1a and 2a in a similar
molar ratio (60:40).
(δ, CDCl3): 7.60-7.34 (m, 15H); 6.92 (t, 1H, JH-H ) 7.3 Hz);
6.83 (d, 2H, JH-H ) 7.6 Hz); 6.69 (d, 2H, JH-H ) 8.2 Hz) (Ph);
6.48 (d, 2H, JH-H ) 7.7 Hz); 6.34 (d, 2H, JH-H ) 7.6 Hz) (Ph,
Tol); 2.15 (s, 3H, CH3); 1.30 (s, 9H, -C(CH3)3). 19F NMR (δ,
Data for 2a were obtained from this mixture (1a + 2a, 60:40).
IR (cm-1): ν(CtC) 2176 (s), 2a. H NMR (δ, CDCl3): 8.38 (d,
1
3
CDCl3): at 293 K, -116.8 (vbr), -117.8 (m, JPt-o-F ≈ 320 Hz)
JH-H ) 9.4 Hz); 7.87 (d, JH-H ) 8.1 Hz); 7.60-6.72 (m); 6.62 (d,
JH-H ) 6.9 Hz); 6.29 (d, JH-H ) 7.2 Hz) (aromatics, 1a + 2a). 19
F
(4o-F); -162.4, -162.3 (overlapping of two triplets, 2p-F); -164.8
3
NMR (δ, CDCl3): -116.6 (m, 3JPt-o-F ≈ 290 Hz, o-F, 1a); -117.3
(m, o-F, 1a + 2a); -117.7 (m, 3JPt-o-F ≈ 265 Hz, o-F, 2a); -161.9
(t), -162.0 (t) (p-F, 2a); -162.7 (t), -162.9 (t) (p-F, 1a); -164.4
to -164.9 (m-F, 1a + 2a). 31P{1H} NMR (δ, CDCl3): 58.92 (s,
1JPt-P ) 2270 Hz); 28.38 (s, 1JPt-P ) 2358 Hz), 2a; signals due to
1a were also present at δ 46.50 and 41.03 (≈ 40:60 2a:1a).
Irradiation of cis-[Pt(C6F5)2(PPh2CtCTol)2]. Formation of
cis-[Pt(C6F5)2{7-CH3-C10H4-1-Tol-2,3-KPP′(PPh2)2}], 1b, and cis-
[Pt(C6F5)2{PPh2C(Ph)dC(Tol)PPh(CtCTol)}], 2b. Following a
procedure similar to that described for cis-[Pt(C6F5)2(PPh2Ct
CPh)2], irradiation of a colorless solution of cis-[Pt(C6F5)2(PPh2Ct
CTol)2] in toluene (0.125 g, 0.111 mmol) for 45 min caused the
formation of a yellow solid, which was identified as a mixture of
1b and 2b (60:40) (0.066 g).
(m, 3m-F); -165.3 (br, 1m-F); at 223 K, -116.8 (m, JPt-o-F
≈
310 Hz, 1o-F); -118.2 (m, 3JPt-o-F ≈ 310 Hz, 1o-F); -118.7 (m,
overlapping of two o-F); -161.5, -161.6 (overlapping of two
triplets, 2p-F); -164.0 (m, 2m-F); -164.3 (m, 1m-F); -164.8 (m,
1m-F). 31P{1H} NMR (δ, CDCl3): 58.42 (s, JPt-P ) 2260 Hz);
1
1
27.60 (s, JPt-P ) 2375 Hz).
Data for 3c. Anal. Calcd for C48F10H38P2Pt (1061.85): C, 54.29;
H, 3.61. Found: C, 53.94; H, 3.91. MS (FAB+): m/z 983 [M -
Ph]+ 42%; 894 [M - C6F5]+ 36%; 727 [M - 2C6F5]+ 46%. IR
(cm-1): ν(CtC) 2211 (m), 2169 (s); ν(CdC) 1603 (w); ν(C6F5)X-sens
790 (sh), 779 (s). 1H NMR (δ, CDCl3): 7.44-6.92 (m, 18H); 6.61
(d, 1H, JH-H ) 7.4 Hz); 6.35 (d, 1H, JH-H ) 7.5 Hz); (aromatics);
1.39 (s, 9H, C(CH3)3); 1.02 (s, 9H, C(CH3)3). 19F NMR (δ, CDCl3):
3
-116.5 (m, br, o-F); -117.6 (vbr, 2o-F); -119.3 (m, JPt-o-F
≈
275 Hz, 1o-F); -162.7 (t), -162.8 (t) (2p-F); -165.0 (m, 4m-F).
Data from the mixture (1b + 2b, 60:40): IR (cm-1): ν(CtC)
2173 (s), 2b. H NMR (δ, CDCl3): 8.35 (d, JH-H ) 9.3 Hz, 1b);
1
1
31P{1H} NMR (δ, CDCl3): 62.97 (s br, JPt-P ) 2241 Hz); 33.12
1
(s br, JPt-P ) 2222 Hz).
7.82 (d, JH-H ) 8.3 Hz, 1b); 7.60-6.69 (m, 1b + 2b) (aromatics);
6.57 (d, JH-H ) 7.8 Hz, 1b + 2b, C6H4, Tol); 6.36 (d, JH-H ) 7.6
Hz, 2b, C6H4, Tol); 6.22 (d, JH-H ) 7.8 Hz, 1b, C6H4, Tol); 2.40,
2.18 (s, CH3), 2b; 2.29, 2.24 (s, CH3), 1b. 19F NMR (δ, CDCl3):
-116.4 (m, 1b), -117.3 (m, 1b + 2b), -117.7 (m, 2b) (o-F);
-162.0 (t), -162.2 (t) (p-F, 2b); -162.9 (t), -163.1 (t) (p-F, 1b);
-164.5 (m br, m-F, 1b + 2b). 31P{1H} NMR (δ, CDCl3): 58.50
(s br, 1JPt-P ) 2261 Hz); 28.48 (s br, 1JPt-P ) 2370 Hz), 2b; signals
due to 1b at δ 46.18 and 40.25 (∼40:60 2b:1b) were also present.
Irradiation of cis-[Pt(C6F5)2(PPh2CtCR)(PPh2CtCt-Bu)].
Synthesis of cis-[Pt(C6F5)2{Ph2PC(Ph)dC(R)PPh(CtCt-Bu)}]
(R ) Ph, 3a; Tol, 3b; t-Bu, 3c). Irradiation of a solution of cis-
[Pt(C6F5)2(PPh2CtCPh)(PPh2CtCt-Bu)] (0.198 g, 0.183 mmol) in
toluene (50 mL) for 30 min, evaporation to small volume, and
addition of n-hexane (∼8 mL) gave complex 3a as a white solid
(0.083 g, 42% yield).
Complexes 3b and 3c were prepared similarly as white (3b) or
beige (3c, 2 h) solids starting from cis-[Pt(C6F5)2(PPh2CtCTol)-
(PPh2CtCt-Bu)] (0.200 g, 0.182 mmol; 0.128 g, 64% yield) or
cis-[Pt(C6F5)2(PPh2CtCt-Bu)2] (0.225 g, 0.212 mmol; 0.131 g, 58%
yield). In the synthesis of 3c on several occasions small amounts
of trans-[Pt(C6F5)2(PPh2CtCt-Bu)2], 4, were also detected in the
final reaction mixture.
Thermal Reactions of cis-[Pt(C6F5)2(PPh2CtCR)(PPh2Ct
Ct-Bu)]. (a) Solid cis-[Pt(C6F5)2(PPh2CtCPh)(PPh2CtCt-Bu)]
(0.05 g, 0.046 mmol) was heated at its melting point (220 °C) for
2 h, giving rise to a dark brown oil. After cooling to room
temperature, the residue was treated with CDCl3 (0.5 mL). Its
31P{1H} NMR spectrum indicates the presence of a mixture of
complexes including 1a (δ 46.53, 41.06), trans-[Pt(C6F5)2(PPh2Ct
Ct-Bu)2] (4) (δ -7.60, 1JPt-P ) 2854 Hz), the precursor, and other
nonidentified species.
(b) A similar experiment with solid cis-[Pt(C6F5)2(PPh2CtCTol)-
(PPh2CtCt-Bu)] (0.05 g, 0.045 mmol) gave a brown oily liquid,
whose 31P{1H} NMR spectrum in CDCl3 mainly shows the presence
of 1b, 4 (∼0.37:1), and the precursor.
(c) cis-[Pt(C6F5)2(PPh2CtCt-Bu)2] was unchanged when heated
at 220 °C for 2 h, showing in the 31P{1H} NMR spectrum only
signals of the starting material.
Synthesis of trans-[Pt(C6F5)2(PPh2CtCt-Bu)2], 4. A solution
of trans-[Pt(C6F5)2(tht)2] (0.122 g, 0.181 mmol) in CH2Cl2 was
treated with PPh2CtCt-Bu (0.096 g, 0.362 mmol), and the mixture
was stirred for 10 min. The solvent was reduced to 2 mL, and
addition of n-hexane (5 mL) afforded 4 as a white solid (0.136 g,
71% yield). Anal. Calcd for C48F10H38P2Pt (1061.86): C, 54.29;
H, 3.61. Found: C, 54.22; H, 3.57. MS (FAB+): m/z 1061 [M]+
5%; 984 [M - Ph]+ 9%; 894 [M - C6F5]+ 57%; 813 [M -
C6F5 - CtCt-Bu]+ 100%; 727 [M - 2C6F5]+ 62%. IR (cm-1):
Data for 3a. Anal. Calcd for C50F10H34P2Pt (1081.84): C, 55.51;
H, 3.17. Found: C, 55.48; H, 3.01. MS (FAB+): m/z 1005 [M -
Ph]+ 6%; 915 [M - C6F5]+ 75%; 748 [M - 2C6F5]+ 100%. MS
(apci-): m/z 1081 [M]- 28%. IR (cm-1): ν(CtC) 2210 (m), 2167
1
ν(CtC) 2215 (m), 2171 (s); ν(C6F5)X-sens 777 (vs). H NMR (δ,

Intramolecular Coupling in Alkynylphosphine Pt(II) Complexes
Organometallics, Vol. 25, No. 16, 2006 3933
1
CDCl3): 7.53 (m, 8H); 7.28 (m, 12H) (Ph); 1.23 (s, 18H, C(CH3)3).
19F NMR (δ, CDCl3): -116.7 (m, 3JPt-o-F ) 240 Hz, 4o-F); -163.3
(m, 2p-F); -164.6 (m, 4m-F). 31P{1H} NMR (δ, CDCl3): -7.60
796 (s), 786 (s). H NMR (δ, CDCl3): 7.62 (m, 4H); 7.34-7.16
1
(m, 19H); 6.99 (d, 2H, JH-H ) 7.5 Hz) (Ph); 5.98 (dd, 1H, JP-H
) 372 Hz, 2JPt-H ≈ 14 Hz, 3JP-H ) 14.5 Hz, P-H). 13C{1H} NMR
1
1
2
(s, JPt-P ) 2854 Hz).
(δ, CDCl3): 145.4 (dt, JC-F ) 230 Hz, JC-F ≈ 20 Hz); 136.9
(dm, 1JC-F ≈ 240 Hz) (C6F5); 133.4 (d, 2JC-P ) 10.9 Hz, 3JC-Pt
≈
Irradiation of cis-[Pt(C6F5)2(PPh2CtC-C6H4-CtCR)2] (R )
Ph, t-Bu). Synthesis of cis-[Pt(C6F5)2{7-CtCR-C10H4-1-(C6H4-
pCtCR)-2,3-KPP′(PPh2)2}] (R ) Ph, 5a; t-Bu, 5c). Irradiation
(45 min) of a solution of cis-[Pt(C6F5)2(PPh2CtC-C6H4-CtCPh)2]
(0.200 g, 0.154 mmol) in toluene, evaporation to small volume,
and addition of n-hexane (∼5 mL) produced 5a as a light yellow
solid (0.154 g, 77% yield).
Complex 5c (0.097 g, 54% yield) was prepared as a beige solid
following a similar procedure, by irradiation of cis-[Pt(C6F5)2-
(PPh2CtC-C6H4-CtCt-Bu)2] (0.180 g, 0.143 mmol).
18.4 Hz, o-C, PPh2); 132.3 (d, 2JC-P ) 12.9 Hz, 3JC-Pt ≈ 16.9 Hz,
o-C, PPh2); 131.9 (d, 4JC-P ) 1.3 Hz, o-C, CtCPh); 130.9 (d, 4JC-P
) 2.3 Hz, p-C, PPh2); 130.7 (d, 4JC-P ) 2.1 Hz, p-C, PPh2); 130.2
3
1
(s, p-C, CtCPh); 129.1 (dd, JC-P ) 1.8 Hz, JC-P ) 63.5 Hz,
2JC-Pt ) 23.8 Hz, i-C, PPh2); 128.2 (overlapping of two d, JC-P
)
10 Hz, m-C, PPh2); 128.1 (s, m-C, Ph); 126.0 (dd, 3JC-P ) 1.8 Hz,
1JC-P ) 56 Hz, 2JC-Pt ) 15.4 Hz, i-C, PPh2); 119.7 (d, 3JC-P ) 3.0
2
3
Hz, i-C, CtCPh); 108.6 (d, JC-P ) 15.2 Hz, JC-Pt ≈ 17.8 Hz,
1
3
Câ, -PCtCPh); 78.1 (dd, JC-P ) 99.6 Hz, JC-P ) 4.7 Hz, CR,
-PCtCPh). 19F NMR (δ, CDCl3): -117.8 (m, 3JPt-o-F ≈ 330 Hz,
4o-F); -162.0 (t, 1p-F); -162.6 (t, 1p-F); -163.9 (m, 4m-F).
31P{1H} NMR (δ, CDCl3): -5.56 (s br, 1JPt-P ) 2223 Hz, PPh2H);
Data for 5a. Anal. Calcd for C68F10H38P2Pt (1302.07): C, 62.73;
H, 2.94. Found: C, 62.87; H, 3.04. MS (FAB+): m/z 1135 [M -
C6F5]+ 56%; 967 [M - 2C6F5 - 1H]+ 88%. IR (cm-1): ν(CtC)
-7.39 (d br, JPt-P ) 2338 Hz, JP-P ≈ 10 Hz, PPh2CtCPh). 31P
1
1
2213 (w), 2173 (w); ν(C6F5)X-sens 790 (m), 780 (m). H NMR (δ,
1
1
NMR (δ, CDCl3): -5.70 (d, JPt-P ) 2238 Hz, JH-P ) 378 Hz,
CDCl3): 8.40 (d, 2H, JH-H ) 9.2 Hz); 7.91 (d, 2H, JH-H ) 8.5
Hz); 7.70 (d, 2H, JH-H ) 8.5 Hz); 7.62-6.98 (m, 28H); 6.36 (d,
4H, JH-H ) 8.0 Hz) (Ph, aromatic). 13C{1H} NMR (δ, CDCl3):
146.6 (dm), 137.1 (dm) (C6F5); 133.5-127.7; 124.1-121.8 (aro-
matics); 92.0; 90.1; 88.6; 88.4 (CtC). 19F NMR (δ, CDCl3): -116.6
(m, 3JPt-o-F ≈ 335 Hz, 2o-F); -117.3 (m, 3JPt-o-F ≈ 310 Hz, 2o-
F); -162.5 (t, 1p-F); -162.8 (t, 1p-F); -164.4 (m, 2m-F); -164.7
1
PPh2H); -7.31 (s br, JPt-P ) 2322 Hz, PPh2CtCPh).
Irradiation of cis-[Pt(C6F5)2(PPh2CtCPh)(PPh2H)]. Synthesis
of cis-[Pt(C6F5)2{Ph2PC(Ph)dC(Ph)PPhH}], 7. A colorless solu-
tion of cis-[Pt(C6F5)2(PPh2CtCPh)(PPh2H)] (0.100 g, 0.100 mmol)
was irradiated for 45 min in toluene. The colorless solution was
evaporated to small volume (∼2 mL) and treated with EtOH
absolute (∼10 mL), which caused the precipitation of a white solid,
7 (0.052 g, 52% yield). Anal. Calcd for C44F10H26P2Pt (1001.71):
C, 52.76; H, 2.62. Found: C, 53.01; H, 2.69. MS (ES-): m/z 1001
[M]- 100%. IR (cm-1): ν(P-H) 2365 (w); ν(CdC) 1605 (w);
ν(C6F5)X-sens 791 (br s). 1H NMR (δ, CDCl3): 7.61-6.80 (m, 23H),
1
(m, 2m-F). 31P{1H} NMR (δ, CDCl3): 46.53 (d, JPt-P ) 2260
1
Hz, JP-P ) 9.2 Hz); 40.95 (d, JPt-P ) 2308 Hz, JP-P ) 9.2 Hz).
Data for 5c. Anal. Calcd for C64F10H46P2Pt (1262.09): C, 60.91;
H, 3.67. Found: C, 61.05; H, 4.05. MS (FAB+): m/z 1262 [M]+
12%; 1095 [M - C6F5]+ 60%; 927 [M - 2C6F5 -1H]+ 100%. IR
(cm-1): ν(CtC) 2219 (w), 2174 (w); ν(C6F5)X-sens 790 (m), 781
1
6.37 (d, 2H, JH-H ) 7.6 Hz) (Ph); 6.60 (d, 1H, JP-H ) 389 Hz,
1
2JPt-H ) 32.3 Hz, P-H). 19F NMR (δ, CDCl3): -118.0 (m, 3JPt-o-F
≈ 325 Hz, 4o-F); -161.4 (t, 1p-F); -162.0 (t, 1p-F); -163.9 (m,
2m-F); -164.6 (m, 2m-F). 31P{1H} NMR (δ, CDCl3): 61.05 (s,
(m). H NMR (δ, CDCl3): 8.32 (d, 2H, JH-H ) 9.1 Hz); 7.80 (d,
2H, JH-H ) 8.5 Hz); 7.60-6.92 (m); 6.81 (d, JH-H ) 7.9 Hz);
6.25 (d, JH-H ) 7.9 Hz) (aromatics); 1.32 (s, 9H, C(CH3)3); 1.24
(s, 9H, C(CH3)3). 13C{1H} NMR (δ, CDCl3): 145.5 (dm), 136.6
(dm) (C6F5); 133.5-127.6; 124.9; 122.9; (aromatics); 101.6; 99.3;
78.5; 78.1 (CtC); 30.7 (s); 30.4 (s) (C(CH3)3); 27.74 (s); 27.70
1JPt-P ) 2247 Hz, PPh2); 28.06 (s, JPt-P ) 2190 Hz, PPhH). 31P
1
NMR (δ, CDCl3): 61.03 (s, 1JPt-P ) 2245 Hz); 28.04 (d, 1JPt-P
≈
1
2190 Hz, JP-H ) 389 Hz).
3
(s) ((C(CH3)3). 19F NMR (δ, CDCl3): -116.5 (m, JPt-o-F ≈ 300
Synthesis of cis-[Pt(C6F5)2{Ph2PC(H)dC(Ph)PPh2}], 8. Com-
plex 8 was obtained quantitatively (31P{1H}) by heating cis-[Pt-
(C6F5)2(PPh2CtCPh)(PPh2H)] (0.050 g, 0.05 mmol) at ∼175 °C
for 1 h. Alternatively, complex 8 was obtained by using (NBu4)-
(acac) prepared in situ: Tl(acac) (0.046 g, 0.150 mmol) was treated
with a CH2Cl2 solution (15 mL) of (NBu4)Br (0.048 g, 0.150 mmol)
at room temperature for 3 h. The resulting TlBr was filtered off
and the filtrate added to a colorless solution of cis-[Pt(C6F5)2-
(PPh2CtCPh)(PPh2H)] (0.100 g, 0.100 mmol) at 0 °C. The mixture
was stirred for 1 h and then evaporated to small volume (∼4 mL).
Addition of i-PrOH (∼10 mL) caused the precipitation of a white
solid, 8 (0.088 g, 88% yield). Anal. Calcd for C44F10H26P2Pt
(1001.71): C, 52.76; H, 2.62. Found: C, 52.35; H, 2.55. MS
(es-): m/z 1001 [M]- 100%. IR (cm-1): ν(CdC) 1601 (m);
3
Hz, 2o-F); -117.3 (m, JPt-o-F ≈ 310 Hz, 2o-F); -162.7 (t,
1p-F); -162.9 (t, 1p-F); -164.4 (m, 2m-F); -164.8 (m, 2m-F).
1
31P{1H} NMR (δ, CDCl3): 46.36 (d, JPt-P ) 2250 Hz, JP-P ≈ 9
1
Hz); 40.70 (d, JPt-P ) 2310 Hz, JP-P ≈ 9 Hz).
{7-CtCt-Bu-C10H4-1-(C6H4-pCtCt-Bu)-2,3-(PPh2)2}. A solu-
tion of cis-[Pt(C6F5)2{7-CtCt-Bu-C10H4-1-(C6H4-pCtCt-Bu)-2,3-
κPP′(PPh2)2}], 5c (0.1 g, 0.079 mmol), in DMSO (15 mL) was
treated with KCN (0.206 g, 3.16 mmol), and the mixture was stirred
at room temperature for 24 h. Addition of n-hexane (30 mL) and
successive portions of water (3 × 5 mL), separation, and evapora-
tion of the organic phase gave a yellow residue. 1H NMR (δ,
CDCl3): 7.63-6.88 (m, 26 H), 6.45 (d, 2H, JH-H ) 8 Hz)
(aromatics); 1.32 (s, 9H, C(CH3)3); 1.24 (s, 9H, C(CH3)3). 31P{1H}
NMR (δ, CDCl3): -8.33 (AB, 2JP-P )155 Hz, δΑ ) -6.14, δΒ )
-10.52).
1
ν(C6F5)X-sens 790 (m), 782 (w). H NMR (δ, CDCl3): 7.57-7.10
(m, 24H); 6.84 (d, JH-H ) 7.4 Hz, 2H). 1H NMR (δ, CD3COCD3):
3
7.92 (d br, 1H, JH-P ) 10.4 Hz, JPt-H ≈ 40 Hz), 7.77-7.47 (m,
Thermolysis of cis-[Pt(C6F5)2(PPh2CtC-C6H4-CtCR)2] (R
) Ph, t-Bu). (a) cis-[Pt(C6F5)2(PPh2CtC-C6H4-CtCPh)2] (0.05
g, 0.038 mmol) and cis-[Pt(C6F5)2(PPh2CtC-C6H4-CtCt-Bu)2]
(0.05 g, 0.040 mmol) were unchanged when heated 6 h at 240-
250 °C (31P{1H} NMR identification).
Synthesis of cis-[Pt(C6F5)2(PPh2CtCPh)(PPh2H)], 6. PPh2H
(85 µL, 0.465 mmol) was added to a colorless solution of cis-[Pt-
(C6F5)2(PPh2CtCPh)(tht)] (0.420 g, 0.465 mmol) in CH2Cl2 (20
mL) at -20 °C, and the mixture was stirred for 2 h. The colorless
solution obtained was evaporated to small volume (∼2 mL) and
treated with EtOH absolute (10 mL) to give 6 as a white solid (0.400
g, 86% yield). Anal. Calcd for C44F10H26P2Pt (1001.71): C, 52.76;
H, 2.62. Found: C, 52.92; H, 2.51. MS (ES-): m/z 1004 [M]-
100%. IR (cm-1): ν(P-H) 2358 (m); ν(CtC) 2177 (s); ν(C6F5)X-sens
20H); 7.27 (d, 1pH, JH-H ) 7.5 Hz, C-Ph); 7.18 (t, 2mH, C-Ph);
7.02 (d, 2oH, JH-H ) 7.5 Hz, C-Ph). 19F NMR (δ, CDCl3): -117.8
(m, 3JPt-o-F ≈ 325 Hz, 4o-F); -162.0 (t), -162.2 (t) (2p-F); -164.4
(m, 4m-F). 31P{1H} NMR (δ, CDCl3): 61.07 (s, 1JPt-P ) 2327 Hz,
PPh2C(Ph)d); 38.98 (s, 1JPt-P ) 2294 Hz, PPh2C(H)d). 31P NMR
(δ, CDCl3): 61.07 (d, 1JPt-P ) 2327 Hz, 3JP-H ≈ 55 Hz); 38.98 (s,
1JPt-P ) 2294 Hz).
Treatment of cis-[Pt(C6F5)2(PPh2CtCPh)(PPh2H)] (0.050 g, 0.05
mmol) in toluene at 383 K for 5 h afforded unchanged starting
material.
X-ray Crystallography. Table 6 reports details of the structural
analyses for all complexes. Colorless crystals of complexes 3a, 7,
and 8 were obtained at low temperature (-30 °C) by slow diffusion

3934 Organometallics, Vol. 25, No. 16, 2006
Table 6. Crystal Data and Structure Refinement Details for 3a, 4, 7‚CHCl3, and 8
Garc´ıa et al.
3a
4
7‚CHCl3
8
empirical formula
fw
C50H34F10P2Pt
1081.80
C48H38F10P2Pt
1061.81
C45H27Cl3F10P2Pt
1121.05
C44H26F10P2Pt
1001.68
temp (K)
293(2)
173(1)
293(2)
293(2)
wavelength (Å)
cryst syst
0.71073
monoclinic
0.71073
monoclinic
0.71073
triclinic
0.71073
monoclinic
space group
a (Å); R (deg)
b (Å); â (deg)
c (Å); γ (deg)
V (Å3); Z
Pc
P21/c
P1h
P21/n
10.8190(3); 90
10.4640(4); 101.693(2)
20.2720(6); 90
2247.37(13); 2
1.599
11.0706(2); 90
17.8513(3); 93.4910(10)
11.1888(2); 90
2207.08(7); 2
1.598
11.7815(2); 73.6040(10)
12.7708(3); 83.7160(10)
15.9553(4); 71.1300(10)
2178.79(8); 2
1.709
10.6341(2); 90
15.9946(3); 91.3550(10)
22.6780(4); 90
3856.18(12); 4
1.725
calcd density (Mg/m3)
abs correction (mm-1
F(000)
)
3.269
1064
3.327
1048
3.553
1092
3.802
1952
cryst size (mm3)
2θ range (deg)
index ranges
0.20 × 0.15 × 0.10
2.74 to 25.36
-11 e h e 13,
-11 e k e 12,
-24 e l e 23
14 546
7327 [R(int) ) 0.0370]
7327/2/571
1.077
R1 ) 0.0349,
wR2 ) 0.0788
R1 ) 0.0407,
wR2 ) 0.0823
0.862 and -1.241
0.40 × 0.30 × 0.10
3.40 to 27.88
-14 e h e 14,
-21 e k e 23,
-14 e l e 14
35 418
5264 [R(int) ) 0.0676]
5264/0/280
1.036
R1 ) 0.0314,
wR2 ) 0.0705
R1 ) 0.0554,
wR2 ) 0.0779
2.156 and -0.969
0.20 × 0.15 × 0.10
2.98 to 27.90
-15 e h e 15,
-16 e k e 16,
-20 e l e 20
19 790
10 153 [R(int) ) 0.0462]
10 153/3/545
1.026
R1 ) 0.0485,
wR2 ) 0.1144
R1 ) 0.0676,
wR2 ) 0.1261
1.409 and -1.231
0.15 × 0.10 × 0.10
3.19 to 27.87
-13 e h e 13,
-21 e k e 21,
-29 e l e 29
29 758
9133 [R(int) ) 0.0709]
9133/0/514
1.050
R1 ) 0.0429,
wR2 ) 0.0680
R1 ) 0.0838,
wR2 ) 0.0788
0.558 and -1.087
no. of reflens collected
no. of indep reflns
no. of data/restraints/params
goodness of fit on F2 a
final R indices [I>2σ(I)]a
R indices (all data)a
largest diff peak and hole (e Å-3
)
2
2
2
2
2
2
a R1 ) ∑(|Fo| - |Fc|)/∑|Fo|; wR2 ) [∑w(Fo - Fc )2/∑wFo ]1/2; goodness of fit ) {∑[w(Fo - Fc )2]/(Nobs - Nparam)}1/2; w ) [σ2(Fo ) + (g1P)2
+
2
2
g2P]-1; P ) [max(Fo ;0) + 2Fc ]/3.
of ethanol into a dichloromethane (3a) solution or by slow diffusion
of n-hexane into chloroform (7, 8) solutions. Colorless crystals of
4 were obtained leaving a diethyl ether solution of this complex to
evaporate at room temperature. For complex 7 one molecule of
chloroform was found in the asymmetric unit (7‚CHCl3). X-ray
intensity data were collected with a NONIUS κ-CCD area-detector
diffractometer, using graphite-monochromated Mo KR radiation.
Images were processed using the DENZO and SCALEPACK suite
of programs.60 The structures of 3a, 4, and 8 were solved by
Patterson and Fourier methods using the DIRDIF92 program,61 and
the absorption corrections were performed using SORTAV.62 The
structure of 7‚CHCl3 was solved by Patterson using the SHELXS-
97 program,63 and the absorption correction was performed using
MULTISCAN.62 All structures were refined by full-matrix least
squares on F2 with SHELXL-97.64
All non-hydrogen atoms were assigned anisotropic displacement
parameters, and all hydrogen atoms were constrained to idealized
geometries, fixing isotropic displacement parameters of 1.2 times
the Uiso value of their attached carbon for the phenyl and methine
hydrogens and 1.5 for the methyl groups. For complexes 4 and
7‚CHCl3, there are peaks of electron density higher than 1 e/Å3 in
the final map, but they are located very close to the platinum atoms
and have no chemical meaning. Complexes 3a and 7‚CHCl3 have
a chiral center at the phosphorus P(1). The absolute structure
parameter for 3a is 0.007(2), which crystallizes in the space group
Pc, and shows the enantiomorphic R form in the crystallographic
study present in this paper (Figure 2). Complex 7‚CHCl3 crystallizes
in the space group P1h; in this case both enantiomers, R and S, are
present in the unit cell (Figure 3 shows the enantiomer S). Finally,
for complex 3a, the low quality of the crystals does not allow the
observation of reflections at high θ.
(60) Otwinowski, Z.; Minor, W. In Methods in Enzymology; Carter, C.
V., Jr., Sweet, R. M., Eds.; Academic Press: New York, 1997; Vol. 276A,
p 307.
(61) Beursken, P. T.; Beursken, G.; Bosman, W. P.; de Gelder, R.; Garc´ıa-
Granda, S.; Gould, R. O.; Smith, J. M. M.; Smykalla, C. The DIRDIF92
program system; Technical Report of the Crystallography Laboratory;
University of Nijmegen: The Netherlands, 1992.
Acknowledgment. This work was supported by the Minis-
terio de Educacio´n y Ciencia (Project CTQ2005-08606-C02-
02 and a grant for A.G.).
Supporting Information Available: Crystallographic data in
CIF format. This material is available free of charge via the Internet
at http://pubs.acs.org.
(62) Blessing, R. H. Acta Crystallogr. 1995, A51, 33.
(63) Sheldrick, G. M. SHELXS97: Program for the Solution of Crystal
Structures; University of Go¨ttingen: Go¨ttingen, Germany, 1997.
(64) Sheldrick, G. M. SHELX-97, a program for the refinement of crystal
structures; University of Go¨ttingen: Germany, 1997.
OM060342Z