Angewandte
Chemie
estingly,the selenol 11 reacted with 7 to give the hydrido PtII
complex 12. When a sufficient amount (two molar equiv-
distorted. While the P1-Pt1-Se1 bond angle (91.10(3) ) is
near 908,the P1-Pt1-P2 bond angle widens to 100.87(4) 8; this
value is larger by about 58 than the corresponding angle in
selenaplatinacycle
8 (95.70(4)8). In hydroselenation of
alkynes employing selenols in the presence of Pt0 cata-
lysts,[13,14] hydrido selenolato platinum(II) complexes were
proposed as key intermediates.[13a] Ananikov et al. succeeded
1
in the observation of trans-[Pt(H)(SePh)(PPh3)2] by H and
31P NMR spectroscopy. The configuration of the two phos-
phane ligands in 12 is cis,in contrast to trans-[Pt(H)(SePh)-
1
(PPh3)2] of Ananikov et al. In the H NMR spectrum of 12,
the proton bound to the Pt atom resonates at d = À6.10 ppm
2
alents) of 7 was employed, 8 and 12 were obtained in 80% and
with J(P,H) couplings of 16 and 184 Hz and with satellite
88% yields,respectively,together with a small amount of
3
signals from the 195Pt isotope separated by 1523 Hz. In
contrast,no 2J(P,H) coupling was observed for trans-[Pt-
(PPh3)2(PhSe)(H)] (1H NMR: d = À8.77 ppm, J(Pt,H) =
999.8 Hz, J(Se,H) = 44.1 Hz). Interestingly,treatment of 12
with HBF4 provided selenaplatinacycle 8 in 60% yield
(Scheme 3). Elimination of a hydride (HÀ) from 12 under
strongly acidic conditions would generate the cationic inter-
mediate 9,which then proceeds to form 8,thus supporting the
mechanism in Scheme 2.
(7%). This result is in marked contrast to the previously
reported reactions of other diselenides (RSeSeR) with
smaller R groups to give the corresponding (diselenolato)PtII
complexes.[3,4]
Hydrido selenolato platinum(II) complex 12 was obtained
in pure form by the reaction of selenol 11 with 7 (Scheme 3).
Complex 12 is stable under ambient conditions,and the
In conclusion,we found that the reactions of selenosele-
ninate 1,selenenic acid 2,and diselenide 3,which have a 9-
triptycyl group,with [Pt(PPh 3)2(h2-C2H4)] 7 gave selenaplati-
À
nacycle 8 by intramolecular C H bond activation. We also
succeeded for the first time in the full characterization of a
hydrido selenolato platinum(II) complex (12). These results
will give a new insight into the reaction of selenium
compounds with low-valent transition-metal complexes. In
the formation of 8,bulkiness of the substituents both on the
selenium atom in 1 and on the platinum atoms in 7 play an
important role. The generality of this reaction is under
investigation,focusing both on the substituents of the organic
selenium compounds and on the phosphane ligands and
metals of low-valent transition metal-complexes.
Scheme 3. The reaction of selenol 11 with 7 giving the hydrido
selenolate platinum(II) complex 12 and the reaction of 12 with HBF4
to give selenaplatinacycle 8.
structure was confirmed unambiguously by X-ray crystallo-
graphic analysis (Figure 2). The sum of the four angles around
the Pt atom is 365.48,and the planarity of the Pt atom is
Experimental Section
Reaction of 1 with 7: A solution of 7 (58.3 mg,0.0780 mmol) in
toluene (5 mL) was added dropwise at room temperature to a
solution of 1 (47.9 mg,0.0704 mmol) in toluene (5 mL) under argon.
The mixture was stirred for 1 h at room temperature and then the
solvent was removed in vacuo. The mixture was subjected to column
chromatography (silica gel). Di-9-triptycyldiselenide (3,14.0 mg,
0.021 mmol,30%) was first eluted with hexane/dichloromethane
(1:1),and then the column was eluted with dichloromethane to give
selenaplatinacycle
8
(53.4 mg,0.0508 mmol,36%).
8: colorless
crystals,m.p. 286–288 8C (decomp). 1H NMR (400 MHz,CDCl
258C,TMS): d = 5.22 (s,1H),5.81–5.88 (m,1H),6.65–6.71 (m,2H),
,
3
6.90–6.98 (m,10H),7.13 (pseudo t, J = 6.9 Hz,3H),7.21 (dt, J = 7.7,
1.9 Hz,6H),7.25–7.36 (m,11H),7.62–7.68 (m,6H),7.98 ppm
(pseudo d, J = 7.6 Hz,2H). Elemental analysis calcd (%) for
C57H44Cl2P2PtSe (C56H42P2PtSe·CH2Cl2): C 60.27,H 3.86; found:
Figure 2. ORTEP drawing of cis-[Pt(H)(SeTrip)(PPh3)2] 12. Thermal
ellipsoids are set at 30% probability. Hydrogen atoms except H1 and
the solvent molecules were omitted for clarity. Selected bond lengths
[] and angles [8]: Pt1–P2 2.2474(12), Pt1–P1 2.3295(12), Pt1–Se1
2.4272(5), Pt1–H1 1.69(5); P2-Pt1-P1 100.87(4), P1-Pt1-Se1 91.10(3),
P2-Pt1-H1 85.65(10), Se1-Pt1-H1 87.8(16), P2-Pt1-Se1 166.89(3), P1-
Pt1-H1 178.9(16).
C 60.74,H 3.90.
Crystallographic
data:
C
63H50P2PtSe
(C56H42P2PtSe·C7H8), Ms = 1143.02,colorless prism,0.25 0.25
0.20 mm3,monoclinic,space group
P21/c, a = 13.9733(8), b =
16.8802(10), c = 20.5325(13) , b = 91.374(2)8, V= 4841.7(5) 3,
1calcd = 1.568 gcmÀ3, Z = 4, m(MoKa) = 3.758 cmÀ1. Intensity data of
9503 unique reflections were collected in the range of À16 ꢀ h ꢀ 17,
À20 ꢀ k ꢀ 20, À16 ꢀ l ꢀ 25 at 183 K. R1 = 0.0346 (I ꢁ 2sI,7858 reflec-
Angew. Chem. Int. Ed. 2008, 47, 2661 –2664
ꢀ 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim