Organometallics 1995, 14, 1756-1760
1756
a-Sulfonyl Carbanion-Transition-Metal Bonds. Alkali-Metal a-Sulfonyl Carbanions and Their Reactivity with Metal Complexes Pier Giorgio Cozzi and Carlo Floriani" Institut de Chimie MinLrale at Analytique, BCH, Universitk de Lausanne, CH-1015 Lausanne, Switzerland
Angiola Chiesi-Villa and Corrado Rizzoli Dipartimento di Chimica, Universita di Parma, I-43100 Parma, Italy Received December 9,1994@ Deprotonation of p-MeC6H4SO2Me (1) with KH in THF in the presence of 18-crown-6 led to the isolation of the ion contact pair [p-MeC6H&(CH2)02-- -K(18-crown-6)1 (2). The a-sulfonyl carbanion has been involved in the derivatization of both early- and late-transitionmetal complexes. When the deprotonation of 1 in situ was followed by a reaction with CpzTiClz (Cp = v5-C5H5), we obtained a Ti-C-bonded a-sulfonyl complex, [Cp2Ti(ClXCH2SOzC&14Me-p)l(41, while the reaction of 2 with CpzZrCl2 led to a 1:l mixture of Zr-C- and Zr-0-bonded a-sulfonyl complexes, [Cp2Zr(C1)(CH2S02C6H4Me-p)](5a) and [CpzZr(Cl)(02S(CH2)C6H4Me-p)](5b). The reaction of the a-sulfonyl carbanion derived from 1 with [cis-Pd(PPh3)2C12]gave a Pd-C-bonded a-sulfonyl complex occurring with the isomerization of the metal center, [ ~ ~ ~ ~ S - ( P P ~ ~ ) ~ ( C ~ ) P ~ - C H(7). ~ S Crystallographic O Z ( J I - M ~ C ~deH~)~ tails: 2 is monoclinic, space group P21/c, with a = 8.635(2) b = 14.879(3) c = 19.589(3) a = y = go", p = 96.30(2)", 2 = 4, and R = 0.057; 4 is monoclinic, space group C2/c, with a = 22.318(3) b = 9.727(2) c = 16.267(3) a = y = go", p = 100.08(2)",2 = 8, and R = 0.047.
A,
A,
A,
A,
w,
A,
The importance of sulfones in organic synthesis stems from their easy conversion into the corresponding a-sulfonyl carbanions, which are employed in a variety of C-C bond formation reactions. The sulfone group has proved t o be enormously valuable in some of the most demanding and difficult total syntheses carried out in recent years.' A number of X-ray structural determinations of a-sulfonyl carbanions were reported by the Boche2and Gais3groups. Such studies were principally devoted to illustrating the configurational and structural characteristics of lithium a-sulfonyl carbanions. Other significant crystal structure determinations have been carried out on organometallic titanium alkoxide4 and potassium derivatives5 of a-sulfonyl carbanions. As an extension of our study into the fundamental aspects of a-carbanions and enolateq6 we report here our preliminary investigation into this closely related field. Deprotonation of methyl p-tolyl sulfone (1)was carried out with KH in THF, and the suspension was then treated with either 18-crown-6or 2,2,2-Kryptofix. The potassium ion pair 2, fully characterized including the * To whom correspondence should be addressed. @Abstractpublished in Advance ACS Abstracts, March 15, 1995. (1) SimDkins. N.J. In Sulphones in Organic Synthesis: Pernamon: Oxford, U:K., 1993. (2)Hollstein, W.;Harms, K.; Marsch, M.; Boche, G. Angew Chem., Int. Ed. E n d . 1988.27.846. Boche, G. Anpew. - Chem., Int. Ed. E n d . 1989,28,277. (3)Gais, H.-J.; Hellman, G.; Gunther, H.; Lopez, F.; Lindner, H. J.; Braun, S. Angew. Chem., Int. Ed. Engl. 1989,28, 1025. Gais, H. J.; Hellman, G.; Lindner, H. Angew Chem., Int. Ed. Engl. 1990,29,100. (4)Gais, H.-J.; Vollhardt, J.;Lindner, H.; Paulus, M. Angew. Chem., Int. Ed. E n d . 1988.27. 1450. (5)Gais,k.-J.; Vollhardt, J.;Kruger, C. Angew. Chem., Int. Ed. Engl, 1988,27,1092. I
I
X-ray analysis reported in Figure 1,is an extremely airsensitive compound. In Table 1, we report significant bond distances and angles for this complex.
2
I SOzMe 1
ocH2
%Y+ Kryptofix
The CH2S02C6H4Me anion interacts with the potassium atom of the K(18-crown-6)cation through the 0 7 and 0 8 oxygen atoms as an asymmetric chelating ligand (Figure 1). The plane through K, 07, and 08 is tilted with respect to the oxygen mean plane by 71.6(1)". The cation has a typical geometry with the potassium atom protruding by 0.803(1) A from the mean least-squares plane running through the six oxygen atoms. The distortions of the oxygen atoms from the mean plane range from -0.258(4) to 0.232(4) A. The sulfur atom lies on the plane of the aromatic ring, which is ap(6)( a ) Veya, P.; Floriani, C.; Chiesi-Villa, A.; Guastini, C. Organometallics 1991,10,1652,2991.(b) Veya, P.; Floriani, C.; Chiesi-Villa, A.; Guastini, C. J. Chem. SOC.,Chem. Commun. 1991, 116. Organometallics 1993,12,253. ( c ) Veya, P.;Floriani, C.; Chiesi-Villa, A,; Guastini, C.; Dedieu, A.; Ingold, F.; Braunstein, P. Organometallics 1993,12,4359. (d) Veya, P.;Floriani, C.; Chiesi-Villa, A.; Rizzoli, C. Organometallics 1993,12,4646.(e) Veya, P.; Floriani, C.; Chiesi-Villa, A,; Rizzoli, C. Organometallics 1993,12,4892. (0 Veya, P.; Floriani, C.; Chiesi-Villa, A,; Guastini, C. Organometallics 1994,13,208. (g) Veya, P.; Floriani, C.; Chiesi-Villa, A,;Rizzoli, C. Organometallics 1994, 13,441.( h )Cozzi, P. G.; Veya, P.; Floriani, C.; Chiesi-Villa, A,; Rizzoli, C. Organometallics 1994,13,1528.
0276-733319512314-1756$09.00/0 0 1995 American Chemical Society
Organometallics, Val. 14, No. 4, 1995 1757
a-Sulfonyl Carbanion-Transition-Metal Bonds
tonation (eq 1) in the presence of Kryptofix gave only uncharacterized decomposition products. This may be due to the very high reactivity of the naked species. For studying the complexation of a-sulfonyl carbanions with transition metals, we prepared the lithium a-sulfonyl carbanion 3, using the recently described LDA-hexane methodology (eq 21.’
C27
C25
C23
Q-Q CH3
c22
C26
CH3
so2cH3
SO~CI+-L~+
3
I
07
08
c2 C8
(2)
We studied the reactivity of lithium and potassium derivatives of methylp-tolyl sulfone with early and late transition metals in order to discover a general approach to organometallic a-sulfonyl carbanion derivatives. However, since the use of the lithium derivative 3 proved troublesome in the isolation and purification of the metal complexes, the potassium complex 2 has been used instead, and to good effect, in the synthesis of transition-metal a-sulfonyl carbanion complexes. Despite the fact that CpzMClz (M = Ti, Zr, Cp = v5-C5H5) reacts with the ion-pair forms of a-sulfinyl anions t o give only decomposition products,6gthe corresponding reactions with the a-sulfonyl carbanion generated in situ give characterizable products (eq 3).
c12
Figure 1. ORTEP drawing for complex 2 (30%probability ellipsoids). Table 1. Relevant Bond Distances (A) and Angles (deg) for Complex 2 Kl-01 Kl-02 KI-03 K1-04 K1-05 KI-06 07-KI-08 C21 -S1 -C28 0 8 - S 1-C28 08-Sl-C21 07-Sl-C28
2.888(5) 3.020(4) 2.861(5) 2.975(4) 2.807(3) 2.894(5) 48.6( 1) I15.7(3) 109.8(3) 103.4(2) 109.6(3)
KI-07 KI-08 SI-07 SI-08 SI-C21 S 1-C28 07-Sl-C21 07-S 1-08 K1-07-S 1 K1-08-SI
2.879(4) 3.094(4) 1.456(4) 1.459(5) 1.810(4) 1.62 l(6) 102.8(2) I15.4(2) 88.8(2) 80.6(2)
proximately coplanar with the K, 07, and 08 plane (dihedral angle of 11.3(1)’). The S-Cip, bond distance corresponds well to a single bond, while the S-C28 and S-0 distances are consistent with some degree of double-bond character. There is one feature which deserves particular attention, i.e. the orientation of the 07, 0 8 , C28 group of atoms which is roughly parallel to the 18-crown-6oxygen plane (dihedral angle of 15.7(l)’), causing the C28 atom to approach the potassium at a distance of 3.403(6)A,indicative of a weak bonding interaction between the two atoms. We assume that the negative charge is delocalized over all three of the atoms without significantly affecting the values of the bond distances. Accordingly, the small influence of the charge distribution on the S-0 distances is further demonstrated by comparing these distances with those of complex 4 (see below), where an expected shortening is not observed, in spite of the charge localization on the carbon atom. The attempt to prepare a naked form of the a-sulfonyl carbanion by carrying out the depro-
1
L. cpzZrClz
CI
\ ,cp ..Zr
0” : ‘cp Me$ CH2
I
5b
Complex 4 has been fully characterized, including an X-ray crystal analysis. A picture of 4 is shown in Figure 2. A chlorine atom and the C17 carbon atom of the a-sulfonyl anion are coordinated to titanium in the equatorial plane of the CpzTi unit. The Ti-C bond distance is remarkably longer than the values generally observed for organotitanium derivatives of Ti(IV).8 The S1-C17 bond distance (1.743(5) is also much lon er than the corresponding one in complex 2 (1.621(6) 1, while the sulfur-oxygen distances are not significantly different from those observed in complex 2. The aromatic ring is nearly perpendicular t o the equatorial plane, with the dihedral angle between the Ti, C11, C17, and the C11, ..., C16 planes being 96.4(1)’. The sulfur atom is significantly displaced from the ring plane by 0.085(1) A. The C17-Sl-Cll-Cl6 torsion angle is
A)
x
(7) Kim, Y.-J.;Bernstein, P.; Galiano Roth, A. S.; Romesberg, F. E.; Williard, P. G.; Fuller, D. J.; Harrison, A. T.; Collum, D. B. J. Org. Chem. 1991,56, 4435. (8) Solari, E.; Floriani, C.; Chiesi-Villa, A.; Rizzoli, C. J.Chem. Soc., Dalton Trans. 1992, 367 and references therein.
1758 Organometallics, Vol. 14,No. 4, 1995
Cozzi et al.
c4
Figure 2. ORTEP drawing for complex 4 (30% probability ellipsoids). Table 2. Relevant Bond Distances (hi) and Angles (deg) for ComDlex 4" Til -Cpl Til -Cp2 Til-CII Til -Cl7 Cp2-Ti I -C 17 Cpl-Til -Cl7 Cpl-Til-Cp2 CII-Til -C17 CI I-Ti I -Cp2 Cll-Til -Cpl Ti I -C17-S 1
2.068(7) 2.059(6) 2.347(2) 2.244(5) 106.7(2) 106.4(2) I3 1.4(3) 87.0(1) 108.1(2) 108.2(2) 126.7(3)
SI-01 s 1-02 SI-c11 SI-c17 0 2 - s 1-c 17 01-SI -C 17 01-s I -c 1 I 01-SI-02 0 2 - s I -CI 1 CI1-Sl-CI7
1.447(4) 1.448(4) 1.77l(4) 1.743(5) 10932) 1 I1.3(2) 106.8(2) I15.8(2) 108.1(2) 104.7(2)
Complexes 6 have been found to be fairly unreactive, although they both react slowly over a period of several days with a typical electrophile, namely benzaldehyde, to afford the same expected product, 6, contaminated with small impurities derived from deoxygenation pathwaysQ (eq 4).
Cpl and Cp2 refer to the centroids of the cyclopentadienyl rings C1C5 and C6-C10, respectively. ('
76.4(4)". The geometries of the a-sulfonyl carbanion in complexes 2 and 4 are very similar except for a rotation of about 20" of the aromatic ring around the C-S bond as shown by the following torsion angles: complex 2, C26-C21-S1-07 = 37.8(4)", C22-C21-S1-08 = -22.6(5)"; complex 4, C12-Cll-S1-02 = 15.4(5)", C16-Cll-S1-01= -41.7(5)". The presence of a Ti-C bond in 4, and likewise in related compo~nds,~ makes such complexes particularly useful for reactivity studies. In addition, complex 4 contains a Ti-C1 group available for further functionalization. The a-sulfonyl carbanion has bonding sites for both carbophilic and oxophilic metals. Therefore, when we shifted our attention onto zirconium, which is much more oxophilic than titanium, we found that the use of Cp2ZrCl2, as shown in eq 3, led to a 1:l mixture of metal-C-bonded (5a) and metal-0-bonded (5b)sulfonyl carbanions. The NMR spectrum of one of the two complexes is quite close to that of 4, while the spectrum of the other one, which we believe to be the 0-bonded form, is remarkably different. The presence of two Cp resonances is in agreement with the presence of a bidentate form of the a-sulfonyl fragment in 5b and accounts for the fact that we did not observe interconversion between the two forms. This latter observation also rules out a possible C,O bidentate bonding mode.
Complex 6 could only be isolated as an oil and was therefore only characterized by lH NMR spectroscopy. Attempts t o isolate the organometallic product in a cationic f ~ r m afforded ~ ~ , ~only secondary products of decomposition. We have further shown that late transition metals are amenable t o this sort of chemistry.6dy6ga-Sulfinyl potassium carbanions react with [cis-(PPh&PdC121 to give the Pd-C-bonded product [trans-(PPh&(Cl)Pd(CH2Soh)],where Ar = C6H5 or p-MeC&. The reaction of [cis-(PPh3)2PdC12]with the a-sulfonyl anion from 1 parallels the reaction we reported with a-sulfinyl derivatives, including the isomerization of the metal center, thus leading to 7.Q It is noteworthy that in these reactions no reduction of the palladium center was observed, despite the reducing nature of such carbanions. Complex 7 is stable and can be handled in air, but we have experienced some difficulties in completely eliminating the potassium chloride byproduct of this reaction. This is probably the result of the strong coordinative interaction of the potassium ion with the oxygens of the sulfone moiety. The NMR data, quite close to those of the analogous a-sulfinyl derivatives,Q (9) Berno, P.; Floriani, C.; Chiesi-Villa, A.; Guastini, C. Organometallics 1990,9,1995.
a-Sulfonyl Carbanion-Transition-Metal Bonds
($
+ K
cis(PPh3)2PdCIt PhP, Pd,CHzS0zCeb-P CI'
Organometallics, Vol. 14, No. 4, 1995 1759 Table 3. Experimental Data for the X-ray Diffraction Studies for Complexes 2 and 4 (5)
'PPh
I
SOzMe
7
I
for which the X-ray analysis is available, allows a confident attribution of the structure for 7 . The reactivity of Pd a-sulfonyl carbanions and the use of the titanium complex as a starting material in organometallic chemistry is under investigation.
Experimental Section All operations were carried out under an atmosphere of purified nitrogen. All solvents were purified by standard methods and freshly distilled prior to use. NMR spectra were recorded on a 200-AC Bruker instrument. Methyl p-tolyl sulfone (1) was prepared according to the literature.1° Preparation of 2. To a solution of 1 (2.02 g, 11.87 mmol) in THF (220 mL) was added KH (0.477 g, 11.92 mmol). The resulting mixture was stirred a t room temperature overnight, and then 18-crown-6 (3.15 g, 11.92 mmol) was added. After a few minutes, a yellow mixture was obtained; the mixture was filtered, and the THF was removed. Diethyl ether was added (60 mL), and the resulting yellow-green product was collected via filtration (2.6 g, 46%). The very sensitive product was purified by extraction with Et2O. IH NMR ( 6 ) : 8.38 (d, 2 H, J = 8 Hz, AA'BB system, Ar);7.12 (d, 2 H, J = 8 Hz, AA'BB' system, Ar); 3.32 (s, 24 H, 18-crown-6); 2.31 (s, 2 H, CH,); 2.04 (s, 3 H, CH3). I3C NMR ( 6 ) : 129.02, 126.21 (Ar); 70.96 (18crown-6); 38.92 (CHz); 21.78 (Me). Anal. Calcd for C20H33KOSS: C, 50.78; H, 6.98. Found: C, 50.76; H, 7.48. Preparation of 3. To a solution of diisopropylamine (16.2 g, 160 mmol) in n-hexane (80 mL) was added a solution of butyllithium in hexane (100 mL, 1.6 M, 160 mmol) in a dropwise manner with stirring a t room temperature. The pale yellow solution was stirred for 1 h, and then a solution of 1 (27.2 g, 160 mmol) in toluene (80 mL) was added dropwise by cannula. The lithium derivative immediately started to precipitate. The resulting suspension was filtered, and the solvent was removed a t low pressure overnight. The residual white powder was stored in sealed ampules (26 g, 92%). IH NMR (pyridine-&; 6 ) : 8.22 (d, 2 H, J = 8 Hz); 7.11 (d, 2 H, J = 8 Hz); 2.41 (s, 2 HI; 2.17 (s, 3 HI. Anal. Calcd for C7H9LiO2S: C, 54.56; H, 5.11. Found: C, 54.01; H, 5.68. Preparation of 4. To a solution of 1(1.3 g, 7.64 mmol) in THF (200 mL) was added KH (0.316 g, 7.9 mmol), and the mixture was stirred overnight a t room temperature. The resulting white slurry was cooled t o 0 "C with an ice bath, and Cp2TiCl2 (1.96 g, 7.89 mmol) was added. The red mixture was stirred a t 0 "C for 6 h and then warmed to room temperature. The red mixture was stirred for a 1day further a t room temperature, and the KCl was filtered off. The resulting orange-red solution was concentrated to about 15 mL, and then Et20 (5 mL) was added in a dropwise manner. After a few hours the solid product was collected via filtration (35%). Another crop of the product was obtained after allowing the remaining filtrate to stand for a few days a t -20 "C (56% total yield). 1H NMR (200 MHz, CD2Cl2; 6): 7.73 (d, 2 H, J = 8.3 Hz, AA'BB' system, Ar); 7.3 (d, 2 H, J = 8.3 Hz, AA'BB' system, Ar); 6.69 (s, 10 H, Cp); 3.14 (s, 2 H, CH2); 2.41 (s, 3 H, Me). 13C NMR (CD2C12; 6 ) : 144.25, 143.25, 130.27, 126.78 (Ar); 119.24 (Cp);66.36 (CH2);21.93 (Me). Anal. Calcd for ClBH1902ClSTi: C, 56.19; H, 4.96. Found: C, 56.07; H, 5.00. Preparation of 5. To a solution of 1 (1.08 g, 6.375 mmol) in THF (150 mL) was added M (0.255 g, 6.375 mmol), and the mixture was stirred a t room temperature overnight. The (10)Organic Synthesis; Wiley: New York, 1963; Collect. Vol. IV, p
674.
2
formula Mi cryst syst space group cell params at 298 K" a, 8, h, 8, c', A P* deg
v,A3 Z
d&dl g cm-' cryst dimens, mm
linear abs coeff, cm-' diffractometer diffraction geometry scan type scan speed, deg min-l scan width, deg radiation data collcn range of 20 range, deg no. of f i n s measd unique total data criterion for observn no. of unique obsd data (NO) no. of params refined (NV) overdetermn ratio (NO/NVj transmissn factors R =IIAFI/WoI R , = [Iw"?lAFI/Cw"?lF~I] GOF= [XwlAFI?/(NO - NV)]"? largest shift/esd, final cycle largest peak, e k'
4
C~IIHUKO~S 472.6 monoclinic P2 I/C
ClxHl9C102STi 382.8 monoclinic c2/c
8.635(2) 14.879(3) 19.589(3) 96.30(2) 250 1.6(9) 4
22.3 18(3) 9.727(2) 16.267(3) 100.08(2) 3476.9( I I ) 8 1.462 0.18 x 0.21 x 0.68 68.04 Siemens AED equatorial 0120 3-12 h
1.255 0.15 x 0.35 x 0.45 29.76 Siemens AED equatorial 6/20 3-12 h c'
c
6- 140 ih,k,l 4732 I > 20(f) 2419 27 I 8.9 0.498- 1.000 0.057 0.07 1
6-140 fh,k,l 3296 I > 2u(r) 2008 208 9.7 0.712- 1.000 0.047 0.057 0.996 0.001 0.41
1.008 0.002 0.25
'' Unit cell parameters were obtained by a least-squares analysis of the setting angles of 25 carefully centered reflections chosen from diverse regions of reciprocal space. /' (0 - 0.6) - [0 (0.6 Aej]; A0 = [(i.az - La~)lI](tan0). ' Graphite-monochromated Cu K a ( I = 1.541 78 Aj.
+
+
resulting white slurry was cooled t o 0 "C, and CpzZrCl?(1.8 g, 6.375 mmol) was added. The yellow mixture was stirred a t 0 "C for 5 h and then warmed to room temperature. The mixture was stirred a t room temperature for 1day more, and then the KCl was removed by filtration. The THF was removed, and ether was then added. The resulting white powder was filtered and collected (72%). The NMR spectra in several different solvents showed an equimolar mixture of two organometallic products. The positions of the signals of the two species are, however, solvent dependent. In THF, a 0.2 M solution of the two species showed no transformation of one species into another after 3 days of stirring at room temperature and then heating. 'H NMR (CD2C12; 6): 7.74 (d, 2 H, J = 8.26 Hz, AA'BB' system, Ar); 7.66 (d, 2 H, J = 8.26 Hz, AA'BB' system, Ar); 7.30 (d, 4 H, J = 8.26 Hz, AA'BB' system, Ar); 6.61 (s, 10 H, Cp); 6.48 (s, 5 H, Cp); 6.37 (s, 5 H, Cp); 2.75 (s, 2 H, CHd; 2.40 (s, 5 H, CH2 and Me); 2.29 (s, 3 H, Me). Anal. Calcd for CleH1&102SZrEt20: C, 52.8; H, 5.8. Found: C, 52.57; H, 5.04. Reaction of 5 with Benzaldehyde: Preparation of 6. In an NMR tube, complex 5 (0.064 g, 0.128 mmol) was suspended in CsDs and then benzaldehyde (0.013 mL, 0.128 mmol) was added. The NMR tube was then frozen, sealed, and warmed to room temperature; the contents were then allowed to react for 2 days. NMR spectra were then run on the resulting orange solution. 'H NMR (C&; 6 ) : 7.76 (d, 2 H, J = 8.0 Hz, AA'BB' system, Ar); 7.28-7.00 (m, 5 H, Ar); 6.66 (d, 2 H, J = 8.0 Hz, AA'BB'system, Ar); 6.31 (s, 5 H, Cpj; 6.03-6.00 (m, 5 H, Cp); 5.97 (dd, 1H, J = 3.8 Hz, CHOZrCpd; 3.25 (dd, 1 H, J = 8.16 Hz, CH2S02Ar); 3.00 (dd, 1H, J = 3.16 Hz, CH2S02Ar); 1.88 (s, 3 H, CH3Ar). Preparation of 7. To a solution of 1 (0.364 g, 2.14 mmol) in THF (80 mL) was added M (0.085 g, 2.14 mmol), and the mixture was stirred a t room temperature overnight. [cis-
Cozzi et al.
1760 Organometallics, Vol. 14, NO.4, 1995
Table 4. Fractional Atomic Coordinates ( x lo4) for Complex 2 atom
.ria
y/h
K1
4685.I ( 12) 2387.0(14) 6950(5) 4538(6) 2323(5) 3297(4) 5826(4) 7923(5) 2347(4) 2163(4) 6881(11) 5 193(12) 2935(10) 2342(8) 1649(7) 1734(7) 348I(8) 5129(8) 7443(7) 7980(7) 8473(8) 8538(8) 634(5) -226(7) - 1574(8) -2083(6) - I174(7) 168(6) -3550(8) 4007(6)
7599.8(7) 7627.4(8) 90333) 9223(2) 7833(3) 6043(2) 5845(2) 7272(3) 8420(2) 677l(3) 9758(5) 9979(4) 935 l(5)
s1
01
02 03 04 05 06 07 08 CI c2
c3 c4 c5 C6 c7 C8 c9 CIO CI 1 c12 c2I c22 C23 C24 C25 C26 C27 C28
8588(5)
7048(5) 6293(5) 5304(4) 5102(4) 5710(4) 6482(5) 8043(6) 8804(5) 7747(3) 6997(4) 7097(5) 7923(5) 8658(4) 8583(3) 8007(7) 7608(4)
ZJC
3143.7(5) I747.0(6) 3220(2) 4060(2) 4045(2) 3810(2) 3033(2) 2971(2) 218l(2) 2085(2) 3685(4) 3764(4) 4137(4) 4495(3) 4317(3) 38333) 3374(3) 3363(3) 2962(3) 2564(3) 2627(4) 3I30(4) 1157(2) 943(3) 495(3) 250(3) 460(3) 915(2) -249(3) I400(3)
Table 5. Fractional Atomic Coordinates ( x lo4) for Complex 4 ~
Ti 1
c1I SI
0 1 02
c1
c2 c3 c4 c5 C6 c7 C8 c9
CIO
c11 c12 C13 C14 c15 C16 C17
CIS
3540.0(3) 4400.7(6) 3818.4(4) 3479(2) 351 l ( 1 ) 3734(3) 3 107(3) 3004(2) 3560(3) 4009(2) 2909(3) 326I(3) 3083(3) 2643(2) 25332) 4492(2) 4712(2) 5252(2) 5577(2) 5347(2) 4806(2) 4070(2) 6183(3)
580.6(9) 1141.7(17) -2470.5(12) - 1853(4) -3562(4) 1172(7) 1232(7) 2318(7) 289l(6) 2155(7) - 1258(7) -850(7) 481(7) 894(6) - 190(8) -3 158(5) -4402(6) -4913(7) -4170(7) -294 l(7) -2403(6) - I23l(5) -4699(9)
1777.7(5) I198.7(9) 300537) 359l ( 2 ) 2491( 2 ) 3236(4) 2944(4) 2368(4) 2280(4) 2829(4) 1175(4) 585(4) 336(4) 790(4) 1303(4) 3601(3) 3385(3) 3829(4) 4481(4) 4703(4) 4268(3) 237l(3) 4938(5 )
(PPhdPdC121 (1.50 g, 2.14 mmol) was added at room temperature, and the mixture was stirred for 2 days. The THF was removed, and CHZClz (120 mL) was added. Small quantities of a yellow solid were eliminated by filtration. CHzClz was removed, and Et20 was added. The resulting yellow solid was isolated by filtration and dried under vacuum (1.1g, 70%). We were unable to make the product free of KCl. ‘H NMR (C6D6; 6 ) : 8.05-7.98 (m, 12 H, Ar); 7.14-7.11 (m, 18 H, Ar); 6.83 (d, 2 H, J = 8.77 Hz, AA’BB‘ system, tolyl); 6.68 (d, 2 H, J = 8.77 Hz, AA’BB’ system, tolyl); 2.65 (t, 2 H, J = 7.68 Hz,
CHd; 1.87 (s,3 H, Me). NMR (C6D6;6): 144.11, 141.2 (tol); 136.58-127.21 (Ar); 21.45 (Me); 1.68 (CH2). 31PNMR (CsDs; 6): 28.77 (PPh3). Crystallography. The crystals selected for study were mounted in glass capillaries and sealed under nitrogen. The reduced cells were obtained with use of TRACER.I1 Crystal data and details associated with data collection are given in Table 3. Data were collected at room temperature (295 K)on a single-crystal diffractometer. For intensities and background, individual reflection profiles were analyzed.I2 The structure amplitudes were obtained after the usual Lorentz and polarization correction^,'^ and the absolute scale was established by the Wilson method.14 Data for both complexes were corrected for absorption using the program ABSORB.15 The function minimized during the full-matrix least-squares refinement was AwlhFI2. Weights were applied according t o the scheme w = k/[u2(F,)+ lg~Fo21. Anomalous scattering corrections were included in all structure factor calculations.16b Scattering factors for neutral atoms were taken from ref 16a for non-hydrogen atoms and from ref 17 for H. Among the low-angle reflections no correction for secondary extinction was deemed necessary. Solution and refinement were based on the observed reflections. The structures were solved by using SHELX8618 for complex 2 and by the heavy-atom method starting from a three-dimensional Patterson map for complex 4. Refinement was first done isotropically and then anisotropically for non-H atoms. Both structures were refined straightforwardly. All the hydrogen atoms were located from difference Fourier maps and introduced in the subsequent refinements as fixed-atom contributions with isotropic Us fixed at 0.08 and 0.10 A2 for 2 and 4, respectively. The final difference maps showed no unusual feature, with no significant peak above the general background. Final atomic coordinates are listed in Tables 4 and 5 for non-H atoms and in Tables S1 and S2 for hydrogens. Thermal parameters are given in Tables S3 and S4 and bond distances and angles in Tables S5 and S6.I9
Acknowledgment. We thank the Fonds National Suisse de la Recherche Scientifique (Grant No. 2040268.94) for financial support. Supplementary Material Available: Listings of anisotropic thermal parameters, atomic coordinates for hydrogen atoms, and all bond lengths and angles (Tables Sl-S6) for complexes 2 and 4 (6 pages). Ordering information is given on any current masthead page. OM940939R (11)Lawton, S. L.; Jacobson, R. A. “TRACER, a Cell Reduction Program; Ames Laboratory, Iowa State University of Science and Technology: Ames, IA, 1965. (12) Lehmann, M. S.; Larsen, F. K. Acta Crystallogr., Sect. A: Cryst. Phys., Diffr., Theor. Gen. Crystallogr. 1974, A30, 580. (13) Data reduction, structure solution, and refinement were carried out on a Gould 32/77 computer using: Sheldrick, G. “SHELX-76: System of Crystallographic Computer Programs”; University of Cambridge: Cambridge, England, 1976. (14) Wilson, A. J. C. Nature 1942, 150, 151. (15) Ugozzoli, F. ABSORB, a program for F, Absorption Correction. In Comput. Chem. 1987, 11, 109. (16) ( a ) International Tables for X-ray Crystallography; Kynoch Press: Birmingham, England, 1974; Vol. IV, p 99. (b) Ibid., p 149. (17) Stewart, R. F.; Davidson, E. R.; Simpson, W. T. J.Chem. Phys. 1966, 42, 3175. (18)Sheldrick, G. “SHELX-86:a FORTRAN-77 Program for the Solution of Crystal Structure from Diffraction Data; University of Cambridge: Cambridge, England, 1986. (19) See the paragraph at the end of paper regarding supplementary material.
