5561
Organometallics 1995, 14, 5561-5565
Optically Active Transition-Metal Complexes. 4.l Rhenium Complexes with the Enantiopure Cyclopentadienyl Ligand PCp: X-ray Structure of the ex0 Isomer of SRe-(PCp)Re(NO) (PPh3)(CH3) Bernhard Pfister, Ulli Englert, and Albrecht Salzer” Institut fur Anorganische Chemie der RWTH Aachen, 0-52056 Aachen, Germany Received June 27, 1995@ Treatment of a 1:1 mixture of the diastereomers S R e - and R~,-exo-[(q~-Pcp)Re(NO)(PPh3)(CO)I+BF4- (la,b)(PCp = “pinene-fused cyclopentadienyl”) with sodium methoxide in methanol affords the derivative “esters” S R e - and RR,-~~o-(~~~-PCP)R~(NO)(PP~~)(COOM~) (2a,b) (SRe:RRe = 1:l). Reaction of 2a,b with (+)-(R)-(1-naphthylethy1)aminegives the “amides” S R e - and Rh-exo-(q5-PCp)Re(NO)(PPh3)[CONHCH(CH3)Cl~H71 (3a,b)(Sh:Rb=1:1). 3a,b are separated by recrystallization. 3a is treated with CF3C02H and NaBF4 to give SRe-( la). l a is then converted to SR,-~~O-(~~-PC~)R~(NO)(PP~~)(CH~) (4a). Protonolysis of 4a with HBFflt20 in CDzCl2 at -78 “C results in solvent-stabilized S~,-exo-[(q~PC~)R~(NO)(PP~~)(C~CDZC~)I+BF~(5a);the thermal and configurational stability of 5a is investigated at various temperatures. An X-ray crystal structure of 4a establishes the absolute configurations of l a , 3a, and 4a.
Introduction
L
We recently described the synthesis of the diastereOmeriC methylrhenium ComplexessRe,RRe-eXo-(?75-Pcp)Re(NO)(PPh3)(CH3)(4a,b)(Figure 112with the optically active pinane-related cyclopentadienyl ligand (lR,8R)Figure 1. S R ~ ~ R ~ ~ ~ O - ( ~ ? ~ - P C ~ ) R ~(4a,b). (NO)(PP~~) (-)-9,9-dimethyltricyclo[6.l.l.O2~6ldeca-2,5-dienyl (PCp-; Figure 2).3-5 Starting from diastereomerically pure exo-(y5-PCp)endo face Re(C013, we obtained, after a sequence of ligand sub4 0 stitutions, the “chiral-at-rhenium”derivatives SRe$Reexo-[(r5-PCpRe(NO)(PPh3)(CO)I+BF4(la,b)and SR~,RR~exo face ’ 1 0 exo-(r5-PCp)Re(NO)(PPh3)(CH3) (4a,b)in good overall yields as 1:1 inseparable mixtures of diastereomers. Figure 2. The PCp- anion and its numbering scheme. Crystallization of 4a,b, for example, afforded the rare case that both diastereomers cocrystallized in a ratio In our last paper we described the conversion of 4a of 1:lin the unit -I- 4b with HBF4.Et20 t o S R ~ ~ R ~ - ~ X O - [ ( ~ ~ - P C ~ ) R Gladysz and co-workers have demonstrated in a host (NO)(PPh3)(ClCD2Cl)I+BF4-(5a,b)in CDzCl2 at -78 “C. of experiments with the Cp analogs of 4a,b that methThe experiment was performed in an NMR tube and ylrhenium complexes such as (r5-Cp)Re(NO)(PPh3)(CH3) immediately analyzed by 31P-NMR at -80 “C. We can readily be converted to chiral, pyramidal, substituobserved two resonance peaks (6 13.4 and 11.9 ppm) tion-labile dichloromethane complexes, [(y5-PCp)Redue to two diastereomers (ratio of integration: SRe:RRe (NO)(PPh3)(ClCH2Cl)I+BF4-, which appear to be of = 1:l). By stepwise warming of the sample to -20 “C, stable configuration in dichloromethane at low temperatures. Generated by protonolysis of (q5-Cp)Re(NO)(7) Gladysz, J. A.; Strouse, C. E.; Merrifield, J . M. Organometallics 1982,I , 1204. (PPh3)(CH3) with HBF4.Et20 in CH2C12 at -78 “C, (8) Gladysz, J . A.; Fernandez, J . M.; Buhro, W. E.; Merrifield, J. M. [(r5-Cp)Re(NO)(PPh3)(ClCH2Cl)l+BF4exhibits overall Inorg. Chem. 1984,23,4022. retention at rhenium after reaction with various neutral (9) Gladysz, J. A.; Fernandez, J. M. Inorg. Chem. 1986,25,2672. (10)Gladysz, J. A.; Fernandez, J. M. Organometallics 1989,8, 207. donor l i g a n d ~ . ~ - l ~
9ql2
a
(1)Part 3: U s e r , M.; Salzer, A. J . Organomet. Chem., submitted
for publication. Abstract published in Advance ACS Abstracts, November 1, 1995. (2) Salzer, A.; Bosch, W. H.; Enplert, U.; Pfister, B.; Stauber, R. J. Organomet. Chem., in press. (3) Paquette, L. A.; McLaughlin, M. L. Org. Synth. 1992,69, 220. (4) Salzer, A.; Schmalle, H.; Stauber, R.; Streiff, S. J . Organomet. Chem. 1991,408, 403. (5) Nelson, J . H.; Bhaduri, D.; Jacobson, R. A,; Wang, T. Organometallics 1994,13, 2291. (6) Gladysz, J . A.; Tam, W.; Lin, G. Y.; Wong, W. K.; Kiel, W. A.; Wong, V. K. J. Am. Chem. SOC.1982,104, 141. @
(11)Gladysz, J . A.; Peng, T. S. J. A m . Chem. SOC.1992,114, 4174. (12) Gladysz, J. A,; Agbossou, F.; OConnor, E. J.; Garner, C. M.; Mendez, N. Q.; Fernandez, J . M.; Patton, A. T.; Ramsden, J . A. Inorg. Synth. 1992,29,211. (13)Gladysz, J. A.; Mendez, N. Q.; Seyler, J. W.; Arif, A. M. J . A m . Chem. SOC.1993,115, 2323. (14) Gladysz, J. A.; Arif, A. M.; Peng, T. S. Helu. C h i n . Acta 1992, 75,442. (15) Gladysz, J. A.; Wang, Y.; Agbossou, F.; Dalton, D. M.; Liu, Y.; Arif, A. M. Organometallics 1993,12, 2699. (16)Gladysz, J. A,; Knight, D. A.; Dewey, M. A,; Stark, G. A,; Bennett, B. K.; Arif, A. M. Organometallics 1993,12, 4523. (17)Gladysz, J. A,; Peng, T. S.; Pu, J . Organometallics 1994,13, 929.
0276-733319512314-5561$09.00/00 1995 American Chemical Society
Pester et al.
5562 Organometallics, Vol. 14, No. 12, 1995
Scheme 2
Scheme 1
7 -
laJh SR,:RR, = 1 : I
SR,:R,,
la
3a
2a,2b =
1:l
I
SRe-isomer
SR,-isomer
NH,R'
NaBH, THF
4a SRe-isomer
3a
3a,3b
+
Conversion of 2a 2b to their derivative "amides" could be performed in good yield in CHzClz by addition of commercial (+I-(R)-(1-(1-naphthy1)ethyl)amineat NH,R': (+)-(R)-1-(1-naphthy1)ethylamine room temperature. The course of the reaction can easily be monitored by IR. After removal of solvent, crude 31P-NMR spectra showed only two resonances, which SR,,RR,-~XO-(~~~-PC~)R~(NO)(PP~~)[ CONHCH(CH3)shifted slightly to higher field, over the entire temperC10H71(3a,b)with the ratio of diastereomers 1:l was ature range. Above -20 "C, decomposition of 5a,b obtained. However, the diastereomeric amides (3a,b) occurred.2 were readily separable by fractional crystallization in From these experiments, it was impossible t o decide benzeneln-hexane. The yellow crystals of the less whether inversion of 5a,b occurred on a time scale soluble diastereomer were collected, washed with nslower than that of the NMR experiment. To answer hexane, and dried to give S~,-exo-(y~-Pcp)Re(NO)this question and unequivocally establish that 5a and (PP~~)[CONHCH(CH~)CIOH~I (3a) of 298% diastereo5b are configurationally stable at temperatures up t o meric ~ u r i t y . ~ -20 "C, it was necessary to also investigate the stability For 3a,b, ratios of diastereomers SR,:RR,were deterof a single diastereomer, either Sa or 5b. mined by 31P-NMR spectra. The assignment of the Our aim was therefore to find a synthetic route to absolute configuration at rhenium of 3a and the subdiastereomerically pure SFW or R~wexo-(v~-PCp)Re(NO)- sequent derived rhenium complexes is based on an (PPh3)(CH3)in good overall yield. X-ray structure analysis of S~,-exo-(y~-Pcp)Re(No)(PPh3)(CH3)(4a) (vide infra). As all these complexes Results and Discussion undergo bond cleavages and metatheses which do not affect any rhenium-carbon bond; retention of the 1. Synthesis and Resolution of Optically Active absolute configuration at rhenium has previously been [CONHCH(CHs)S ~ , - e x o - ( q ~ - P C p ) R e ( N(PPh3) o) established. CIOH,](3a). To obtain diastereomerically pure ex0-(y52. Preparation of S,~-(~5-PCp)Re(NO)(PP~)PCp)Re(NO)(PPh3)(CH3), we used a reaction pathway CH3) (4a). The amide linkage of 3a was cleaved with quite similar to that found by Gladysz and co-worke r ~ . S~R,, ~~R~, - ~ X O - [ ( ~ ~ - P C ~ ) R ~ ( N O ) ( P P ~ ~ ) ( C OCF3COzH ) ] + B F ~ - in CH2C12 at 0 "C, and the optically active SR,-~~O-[(~~-PC~)R~(NO)(PP~~)(CO)]+CF~CO thus (la,b) (ratio of 1a:lb = 1:l)were prepared as deformed was metathesized to the BF4- salt, la, which scribed.2,6J2l a l b were then treated with sodium has a higher tendency t o precipitate (Scheme 2).12 methoxide in methanol and stirred for 10 h at ambient temperature. After work-up S ~ e P ~ , e x o - ( y ~ - P c P ) R e - Reduction of l a by treatment with NaBH4 in THF at ambient temperature resulted in diastereomerically (NO)(PPh3)(COOMe)(2a,b)could be obtained in excel(4a)(Scheme pure SR,~~O-(~~~-PC~)R~(NO)(PP~~)(CH~) lent yield as a light yellow solid with the ratio of 2). Evaporation of solvent, purification by chromatogdiastereomers 1:l (Scheme 1). raphy, and subsequent crystallization from a saturated The ratio of diastereomers was determined by intetoluene solution, layered with 6 equiv of n-hexane, gration of both the lH-NMR peaks assigned to the afforded red single crystals of 4a after 2 d. A crystal methoxy groups (6 3.12 and 3.08 ppm) and the 31P-NMR structure analysis of 4a established the absolute conpeaks (6 19.5 and 19.3 ppm) of 2a,b. As 2a,b exhibit figuration at rhenium of 3a, la, and 4a. the same IR absorptions in the nitrosyl and carbonyl region, they cannot be distinguished by IR spectroscopy. 3. X-rayStructure of 4a. The solid-state structure 13C-NMRspectra of 2a,b show only one doublet resoanalysis of complex 4a shows the expected orientation nance for the CO ligands with identical chemical shifts of the bulky PPh3 group positioned as far as possible for 2a,b. away from the sterically demanding pinene part of the SR,-isomer
S R , : R R ~ =1:1
+
Organometallics, Vol.14,No. 12, 1995 5563
Table 1. Fractional Atomic Coordinates and Equivalent Isotropic Displacement Parameters (A2)of S~-e~o-(PCp)Re(NO)(PPhs)(Ca) (4a) with Estimated Standard Deviations in Parentheses X Y z UeqP Re P 0 N
0.34557(4) 0.5363(3) 0.3283(9) 0.3416(9) c1 0.346(2) C10 0.118(1) C11 0.004(1) C12 -0.000(1) C13 0.067(1) C14 0.075(1) C15 -0.011(1) C16 -0.084(1) C20 0.176(1) C21 0.202(1) C22 0.300(1) C23 0.334(1) C24 0.257(1) C31 0.611(1) C32 0.553(2) C33 0.614(2) Figure 3. Molecular structure and crystallographic numc34 0.723(1) bering scheme of SR,-~XO-(~~~-PC~)R~(NO)(PP~~)(CH~) (4a). C35 0.727(1) C36 0.777(1) C41 0.606(1) C42 0.562(1) C43 0.612(1) C44 0.711(1) C45 0.761(1) C46 0.709(1) C51 0.585(1) C52 0.581(1) C53 0.619(1) C54 0.645(1) C55 0.639(2) C56 0.617(1)
x
yx
0.99547(5) 1.0020(4) 0.999(1) 1.001(1) 1.153(1) 1.062(1) 1.012(1) 1.016(1) 0.934(1) 1.108(1) 0.909(1) 1.078(1) 0.922(1) 0.987(1) 0.949(1) 0.866(1) 0.849(1) 0.8977(9) 0.833(1) 0.755(1) 0.739(1) 0.880(1) 0.796(1) 1.107(1) 1.157(1) 1.233(1) 1.266(1) 1.212(1) 1.135(1) 1.006(1) 1.0922(9) 1.093(1) 1.007(1) 0.921(1) 0.916(1)
0.83871(3) 0.8308(2) 1.0216(5) 0.9465(6) 0.805(1) 0.7221(9) 0.7168(7) 0.8144(7) 0.8550(8) 0.806(1) 0.6793(9) 0.674(1) 0.8121(9) 0.7449(7) 0.7091(8) 0.7512(9) 0.813(1) 0.8733(7) 0.927(1) 0.965(1) 0.9411(9) 0.856(1) 0.8847(9) 0.8854(8) 0.9454(8) 0.982(1) 0.9642(8) 0.9021(9) 0.8595(7) 0.7232(6) 0.6789(8) 0.5960(9) 0.5557(7) 0.598(1) 0.6810(8)
0.02999(9) 0.0302(7) 0.072(3) 0.045(3) 0.059(5) 0.040(4) 0.050(4) 0.046(4) 0.047(5) 0.053(5) 0.064(6) 0.079(6) 0.046(4) 0.033(3) 0.039(4) 0.047(4) 0.041(4) 0.029(4) 0.062(6) 0.074(6) 0.047(5) 0.063(6) 0.045(5) 0.032(4) 0.038(4) 0.061(6) 0.043(4) 0.047(5) 0.029(4) 0.031(3) 0.028(3) 0.050(5)
0.066(4) 0.081(7) 0.037(4)
U values for anisotropically refined atoms are given in the form of the isotropic equivalent displacement parameter defined as one-third of the trace of the orthogonalized U tensor.
U Figure 4. Top view of 4a.
Table 2. Selected Bond Lengths (A)and Angles (4a) with (deg) of S~-exo.(PCp)Re(NO)(PPhH)(CHS) Estimated Standard Deviations in Parentheses ~~
Bond Lengths 2.324(3) Cll-c12 1.73(1) Cll-C15 2.20(1) Cll-C16 2.33(2) C12-Cl3 2.31(1) C12-Cl4 2.24(1) C13-C20 2.25(2) c20-c21 2.30(1) C20-C24 1.22(1) c21-c22 1.54(2) C22-C23 1.57(2) C23-C24 1.49(2)
PCp ligand (Figures 3 and 4). The small NO and methyl Re-P 1.57(2) ligand are well shielded below the n-plane. The bond Re-N 1.53(3) Re-C1 1.55(2) angles at the metal center deviate distinctly from an Re-C20 1.52(2) octahedral coordination of go", and the Re-C distances Re-C21 1.55(2) t o the cyclopentadienyl ring range from 2.20 to 2.30 A. Re-C22 1.51(2) A summary of crystal data, data collection parameters, Re-C23 1.42(2) Re-C24 and convergence results for 4a is given in Table 3. 1.39(2) 0-N 1.42(2) Fractional atomic coordinates and equivalent isotropic c10-c11 1.38(2) displacement parameters are listed in Table 1, and ClO-Cl4 1.38(2) selected bond lengths and angles in Table 2. ClO-C21 4. Formation and Stability of Swexo-[(rf-PCp)Bond Angles R~(NO)(PP~~)(C~CDBC~]+BF~(5a). Similar to the P-Re-N 94.6(4) C11-C10-C21 109(1) NMR experiment which we had already conducted with P-Re-C1 86.9(6) Cll-Cl2-Cl3 113(1) the 1:l mixture of diastereomers 4a,b,299we treated N-Re-C1 101.6(7) Cll-Cl2-Cl4 86(1) 173(1) C12-Cll-Cl5 115(2) ) ( P P ~ ~ ) Re-N-0 (CH~) optically active S R , ~ ~ O - ( ~ ~ ~ - P C ~ ) R ~ ( N O (4a) c21-c2o-c24 107(1) C12-Cll-Cl6 114(1) with a stoichiometric amount of HBF40Et20 in CDzCl2 c10-c11-c12 88(1) C12-C13-C20 111(1) at -78 "C. The conversion to the corresponding (dichloClO-C11-C15 122(2) C13-Cl2-Cl4 108(1) rometharielrhenium complex (Sa)was performed in an ClO-Cll-Cl6 113(2) c13-c2o-c21 118(1) ClO-C14-C12 87(1) c13-c2o-c24 134(2) NMR tube and immediately analyzed at -80 "C by 31PC1O-C21-C20 117(1) c14-c1o-c21 107(1) NMR (Scheme 3). ClO-C21-C22 136(1) C15-Cll-Cl6 106(1) Only one resonance peak (6 13.5 ppm) due to one c11-c1o-c14 86(1) diastereomer could be observed. When the probe was warmed stepwise to -20 "C, the 31P-NMR spectra with formation of new complexes (presumably chloro showed only one resonance over the entire temperature complexes),but even then no resonance due to 5b could range (Figure 5). Above -20 "C, decomposition occurred be observed.
5564 Organometallics, Vol. 14, No. 12, 1995
Scheme 3
Pfister et al. of S~eP~,-exo-(y~-PCp)Re(NO)(PPh3)(COzCH3) (2a,b),which was collected by filtration and dried under oil pump vacuum; yield of 2a 2b, 3.63 g (5.21 mmol, 95%), with the ratio of diastereomers S R ~ : R=R1:l. ~ 2a 2b: IR 1681,1596 cm-l (n-hexane); IR 1655,1585 cm-' (CHZClZ);'H-NMR (500 MHz, CDC13) 6 7.69-7.35 (m, 30H, 6 x Ph), 5.18 (br, lH), 5.04 (br, lH), 4.46 (br, lH), 4.42 (dd, J = 2.8, 1.5 Hz, l H ) , 4.34 (dd, J = 4.9, 2.5 Hz, lH), 4.23 (dd, J = 4.9,2.5 Hz, lH), 3.12 (s,3H, OCH3), 3.08 (s,3H, OCHs), 2.882.59 (m, 8H), 2.24 (m, 2H), 1.70 (d, J = 10.1 Hz, lH), 1.69 (d, J = 10.1 Hz, lH), 1.42 (s,3H, CH3), 1.40 (s,3H, CH3), 0.77 (s, 3H, CH3), 0.74 (s, 3H, CH3) ppm; W-NMR (125 MHz, CDC13) 6 198.5 (d, J c p = 4.1 Hz), 135.7 (d, J c p = 54.0 Hz), 133.7 (d, J c p = 10.9 Hz), 130.1, 128.2 (d, J c p = 10.9 Hz), 126.3, 121.0, 107.6, 104.7, 90.8,90.0, 89.3, 88.7, 87.6, 85.9,49.6, 49.2,42.1, 41.8, 41.6, 41.5, 41.3, 41.1, 37.2, 35.9, 31.6, 27.1, 26.8, 26.6, 22.7, 22.0 ppm; 31P-NMR(202 MHz, CDC13) 6 19.5, 19.3 ppm. Anal. Found: C, 55.15; H, 4.89; N, 1.90. Calc for C32H33N03PRe: C, 55.16; H, 4.77; N, 2.01.
+
L
+
4a
5a
SR,-isomer
SR,-isomer
One might argue that 5a,b are diastereomers of different thermodynamic stability so that an interconversion of 5a to 5b was not possible for thermodynamic reasons. However, as a 1:l mixture of 5a,b also did not change in ratio up to -20 "C, we conclude that the inversion barrier of 5a is high enough so that decomposition occurs faster than inversion. These NMR S~-exo-(q5-PCp)Re(NO)(PPhs)[CONHCH(CH3)CloH,1 measurements make it possible for the first time to (3a). A 2.14 g amount (3.07 mmol) of 2a + 2b was dissolved estimate a lower value for the inversion barrier of these in 10 mL of dichloromethane. A 0.99 mL amount (6.14 mmol) chiral, pyramidal dichloromethane complexes (AG* L of commercial (+)-(R)-(l-(l-naphthy1)ethyl)amine was added by syringe, and the yellow solution was stirred for 8 h a t 47.9 f 0.8 kJ mol-l). These experiments also clearly ambient temperature. The progress of the reaction was establish the usefulness of optically active cyclopentamonitored by IR. Evaporation of the solvent afforded a yellowdienyl ligands as spectroscopic probes in mechanistic brown oil of crude S R ~ ~ P R ~ ~ ~ - ( ~ ~ - P C ~ ) R ~ ( N O ) ( P P ~ ~ ) [ C O N H studies where chirality is involved. Up t o now, it had (CH~)CI~H (3a ~ ]+ 3b) and residual amine. This oil was only been possible to determine the stability of funcdissolved in 10 mL of benzene, upon which 35 mL of n-hexane tional equivalents of the chiral, 16-valence-electron was layered. The layers were allowed to diffuse for 6 d, and Lewis acids SR~PR~-[(~;~~-C~)R~(NO)(PP~~)~+ by indirect the resulting yellow crystals were collected and washed with m e t h o d ~ ~and , ~ Jnot ~ by a simple NMR experiment. n-hexane t o give SR,-~~~-(~~-PC~)R~(NO)(PP~~)[CONH We are currently studying other organometallic sys(CH~)CIOH (3a) ~ ] of 298% diastereomeric purity; yield of 3a, tems, where the formation of metal-centered chirality 0.96 g (1.15 mmol, 75%). 3a: IR 1631,1535 cm-' (CHzC12);'H-NMR (500 MHz, CD2can be monitored (and not induced) by chirality in the Cl2) 6 8.14 (d, J = 8.2 Hz, lH, naphthyl), 7.83 (dd, J = 7.9, 1.2 cyclopentadienyl ring. Hz, l H , naphthyl), 7.70 (d, J = 7.9 Hz, l H , naphthyl), 7.577.41 (m, 19H, naphthyl and phenyl), 5.54 (m, 2H, NCH and Experimental Section
NH), 5.24 (br, lH), 4.63 (dd, J = 2.8, 1.5 Hz, lH), 3.91 (dd, J = 2.8, 2.1 Hz, lH), 2.73 (m, 2H), 2.51 (m, l H ) , 2.34 (m, lH), General Data. All reactions and manipulations were 2.09 (m, lH), 1.34 (d, J = 10.1 Hz, lH), 1.31 (s, 3H, CH3), 0.99 performed under nitrogen by use of standard vacuum line and (d, J = 6.7 Hz, 3H, CH3), 0.71 (s, 3H, CH3) ppm; 13C-NMR Schlenk tube techniques. All solvents were degassed before (125 MHz, CD2C12) 6 191.5 (d, J c p = 10.9 Hz), 142.6, 136.9 (d, use. Diethyl ether and THF were distilled from sodium J c p = 53.4 Hz), 134.2 (d, J c p = 10.9 Hz), 131.5, 130.5, 128.8, benzophenone ketyl. Methanol was distilled from magnesium 128.6 (d, J c p = 10.4 Hz), 127.2, 126.0, 125.7, 124.6, 122.6, filings. Dichloromethane, benzene, toluene, and n-hexane 121.3, 105.0,93.5,91.4,87.5,44.5,42.0,41.64,41.60,37.7,27.4, were dried over molecular sieves. Unless otherwise indicated, 26.8,22.0, 21.5 ppm; 31P-NMR(202 MHz, CD2Clz) 6 18.6 ppm. all commercially available reagents were used as received. Anal. Found: C, 61.89; H, 5.13; N, 3.32. Calc for C43H42N202Column chromatography was performed on grade I1 (activated) PRe: C, 61.78; H, 5.06; N, 3.35. silica gel (Merck Kieselgel60). For organometallic complexes, S~-eso-(tls-PCp)Re(NO)(PPh~)(CHs) (4a). 3a (0.32 g, all chromatography was carried out under nitrogen. (+)
[email protected] mmol) was dissolved in 1.5 mL of dichloromethane, and (1-(1-naphthy1)ethyl)amine(Aldrich),HBF4 (54%in EtzO), CF3the solution was kept a t 0 "C with an ice bath. While the COzH (Merck), NaBF4, and NaBH4 (Fluka) were used as ) ( P P ~ ~ ) solution ~ + B F ~was - stirring, 73 pL (0.96 mmol) of CF3C02H was supplied. S R ~ P R ~ ~ O - [ ( ~ ~ - P C ~ ) R ~ ( N O ) ( C O(la,b) added by syringe. The solution was stirred for 10 min at 0 were prepared as described in the literature.2J2 Infrared "C. The solvent was then removed under reduced pressure to spectra were recorded on a Perkin-Elmer 1750 Fourier transform spectrophotometer as solutions in n-hexane or dichlogive a yellow foam. The residue was taken up in 1.5 mL methanol, and a solution of NaBF4 (0.08 g, 0.76 mmol) in water romethane using NaCl cells. NMR spectra were recorded on (0.75 mL) was added with vigorous stirring. A yellow solid either a Varian VXR 300 or a Varian Unity 500 spectrometer precipitated. Additional water (2.5 mL) was added, and the in CDC13 or CDzClz solutions unless otherwise stated. 'H- and mixture was stirred for 15 min. The yellow precipitate was 13C-NMRspectra were referenced t o tetramethylsilane (TMS) collected by filtration, washed with water (4 x 2.5 mL), washed using internal solvent peaks; 31P-NMRspectra were referenced with n-hexane, and dried under oil pump vacuum to afford t o H3P04 (external). In the Experimental Section, 13C- and 31P-NMR data are given in terms of the proton-decoupled SR~-~~~-[(~~-PC~)R~(NO)(CO)(PP~~)~+BF~(la);yield of la, 0.27 g (0.36 mmol, 95%). (broad band) spectra. S ~ ~ R R , - ~ ~ ~ - ( ? ~ - P C ~ ) R ~ ( N O ) ( P(2a,b). P ~ ~ )A( C O ~ CAH0.27 ~ ) g (0.36 mmol) amount of l a was dissolved in 25 mL solution of 4.12 g (5.48 mmol) of l a + lb (ratio of 1a:lb = of THF. While the mixture was stirred, 0.043 g (1.15 mmol) 1:l)in 60 mL of methanol was treated with 4.37 M sodium of NaBH4 was added. The solution was stirred for 3 h at room methoxide in methanol (8.64 mL, 37.74 mmol). The suspentemperature. The solvent was then removed under reduced sion was stirred a t room temperature for 10 h. The solvent pressure, and the residue was extracted with toluene and was then removed and the brown residue extracted with hot filtered. Chromatography over silica gel (1.5 x 20 cm) in n-hexane and filtered. The orange filtrate was concentrated toluene and evaporation of the solvent gave an orange solid. and recrystallized a t -30 "C to afford a light yellow precipitate This was dissolved in 1 mL of toluene, upon which 6 mL of
Organometallics, Vol. 14,No.12, 1995 5565
I
1
23
~
~
22
~
21
'
I
20
~
~
19
"
1
1B
~
~
17
~
'
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Figure 5. 31P-NMR spectra of SR,-~X~-[(~~-PC~)R~(NO)(PP~~)(C~CD~C~)~+BF~(Sa)in CDzClz at various temperatures. Note that the spectra at -60, -40, and -20 "C have been displaced to t h e right for clarity. Table 3. Summary of Crystal Data and Details of n-hexane was layered. The layers were allowed t o diffuse for the Intensity Collection and Refinement for 2 d to afford red single crystals of S~,-exo-(y~-PCp)Re(N0)Srce-exo-(PCp)Re(NO)(PPh3)(CH3) (4a) (PPh3)(CH3)(4a),which were filtered off and dried: yield of formula C31H33NOPRe 4a, 0.19 g (0.29 mmol, 80%); mp 150 "C. fw 652.79 la: IR 2015, 1754 cm-l (CH2C12); lH-NMR (500 MHz, color, habit red rod acetone-ds) 6 7.67 (m, 9H, Ph), 7.50 (m, 6H, Ph), 6.19 (br, lH), cryst size, mm3 0.17 x 0.17 x 0.45 5.68 (br, l H ) , 5.42 (dd, J = 6.1, 2.8 Hz, lH), 3.27-2.83 (m, cryst system orthorhombic 4H), 2.40 (m, lH), 1.46 (s, 3H, CH3), 1.35 (d, J = 10.4 Hz, l H ) , space group P212121 (NO.19) 0.80 (s, 3H, CH3) ppm; 13C-NMR(125 MHz, acetone-&) 6 197.9, a, A 12.156(3) 134.0 (d, J c p = 9.9 Hz), 133.1, 131.8 (d, J c p = 60.3 Hz), 130.5 b, A 13.531(4) (d, J c p = 11.5 Hz), 129.2, 113.5,96.3,93.9,87.4,42.1,41.9,41.8, C, A 16.066(4) 37.0, 27.2, 26.5, 22,l ppm; 31P-NMR(202 MHz, acetone-&) 6 v, A3 2643(1) z 4 11.3 ppm. d(calc),g cm-3 1.640 4a: IR 1631 cm-l (THF); IR 1613 cm-' (CH2C12); lH-NMR F(000) 1296 (500 MHz, CDzC12) 6 7.39 (m, 15H, 3 x Ph), 5.20 (br, lH), 4.02 abs coeff 01, cm-l) 47.41 (dd, J = 2.8, 1.5 Hz, l H ) , 3.62 (m, lH), 2.83 (m, 3H), 2.56 (m, abs corr numerical l H ) , 2.21 (m, l H ) , 1.54 (d, J = 9.8 Hz, l H ) , 1.42 (s, 3H, CH3), madmin transm 0.5310.26 0.93 (d, J = 6.1 Hz, 3H, CH3), 0.78 (s, 3H, CH3) ppm; 13Cradiation (A,A) Mo K a (0.710 73) NMR (125 MHz, CDzClz) 6 137.2 (d, J c p = 50.3 Hz), 134.0 (d, temp, K 263 J c p = 10.6 Hz), 130.2, 128.5 (d, J c p = 10.1 Hz), 118.8, 101.6, scan mode (0 range, deg) w (3-25) no. of unique rflns 3237 91.4, 88.5, 83.5, 41.7, 41.5,41.4, 37.2, 30.1, 27.3, 27.0, 22.0, No,no. of obsd rflns 2407 (Z > l.Oo(Z)) -35.7 (d, J c p = 6.6 Hz) ppm; 31P-NMR(202MHz, CD2C12) d N p ,no. of params refined 316 26.9 ppm. Anal. Found: C, 56.85; H, 5.16; N, 2.21. Calc for weighting scheme w - l = u2( F J C31H33NOPRe: C, 57.04; H, 5.10; N, 2.15. R 0.048 Crystal Structure Determination of 4a. A saturated RW 0.046 solution of 4a in toluene, layered with 6 equiv of n-hexane, GOF 1.156 afforded red single crystals after 2 d of layer diffusion. The resid fluctuation in final DF map, 1.7, 0.8 A from Re crystals of 4a were filtered off and dried under oil pump e1A3 vacuum. Data collection was performed with a n Enraf-Nonius CAD4 diffractometer equipped with a graphite monochromawas added by syringe. The tube was shaken and placed in a tor. Crystal data, data collection parameters, and convergence -80 "C NMR probe. 31P-NMRspectra at various temperatures results are given in Table 3. Before averaging over symmetrywere recorded. related refle$ions, a numerical ab_s_orptioncorrection (crystal Sa: 31P-NMR (202 MHz, CDzClz) 6 13.5 ppm (at -80 "C). faces: 101, 101, 101, 101, 111, 111, 010) was applied. The structure was solved by direct methods1*and refined on F with Acknowledgment. The authors are grateful for the SDP program system.Ig In the final refinement cycles, financial support from the Deutsche Forschungsgemeinhydrogen atoms were included as riding on the corresponding schaft ( G r a n t SFB 380) and from the "Fonds d e r carbon atoms (C-H = 0.98 A). Fractional coordinates of the chemischen Industrie". non-hydrogen atoms are compiled in Table 1. S ~ , - ~ ~ O - [ ( ~ ~ - P C ~ R ~ ( N O ) ( P P ~ ~ ) ( C ~(5a) CD~C~)]+BF~Supporting Information Available: Tables giving a (NMR Experiment). A 5-mm NMR tube was charged with structure report on the X-ray data collection and refinement, 0.040 g (0.061 mmol) of 4a and 0.50 mL of CDzClp. The tube positional and thermal parameters for all atoms, anisotropic was cooled to -78 "C, and HBF4.Et20 (8.4 pL, 0.061 mmol) displacement parameters (U), and bond lengths and bond angles and a n ORTEP drawing for 4a (12 pages). Ordering (18)Sheldrick, G. M. SHELXS-86; Program for Crystal Structure information is given on any current masthead page. Solution; University of Gottingen, Gottingen, Germany, 1986. (19) Frenz, B. A. Enraf-Nonius Structure Determination Package, Version 5.0, Delft, The Netherlands, 1989. OM950498R
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