0 Copyright 1995
Volume 14, Number 2, February 1995
American Chemical Society
Communications Transition-Metal-SubstitutedAcylphosphanes and Phosphaalkenes. 26.l Synthesis and Structure of the 2-Metallo-1,2,3-diazaphospholes I
(q5-C5Mes)(C0)2Fe-N-P=C(NMe2)-C(C02R)=N (R = Et, tBu)
Lothar Weber," Olaf Kaminski, H.-G. Stammler, and Beate Neumann Fakultat fur Chemie, Universitat Bielefeld, Universitatsstrasse 25, D-33615 Bielefeld, Germany Received November 15, 1994@ Summary: Treatment of the metallophosphaalkene (r5CsMes)(CO)2Fe-P=C(NMed2 with diazoacetates N Z CHCOZR(R = Et, tBu) afforded the novel N-metalated
, NMe2
[Fel,
I P-c
1,2,3-diazaphospholes (q5-C5Mes)(CO)2Fe-N-P=C(NMedC(COd?)=N (R = Et, tBu) as the formal result of a dipolar [3 21 cycloaddition which is followed by the elimination of dimethylamine and a sigmatropic 1,2shift of the metal fragment from phosphorus to nitrogen. The molecular structure of one representative (R = tBu) was established by a single-crystal X-ray analysis.
+
The combination of reactive sites in metallophosphaalkenes such as (q5-CsMes)(CO)2Fe-P=CR1R2 (R1 = R2 = s i M e ~NMez3) ,~ renders them versatile as useful building blocks in organometallic synthesis. Thus, the compound (r5-CsMes)(CO)2Fe-P=C(MMe2)2 (1)was conveniently converted into l-metallo-1,2-dihydrophosphetes I3and IV4when reacted with fumarodinitrile and dimethyl fumarate or methyl butynoate, respectively. @Abstractpublished in Advance ACS Abstracts, January 1, 1995. (1)Part 25: Weber, L.; Kaminski, 0.;Boese, R.; Blaser, D. Organometallics, in press. (2) Niecke, E.; Metternich, H.-J.; Nieger, M.; Gudat, D.; Wenderoth, P.; Malisch, W.; Hahner, C.; Reich, W. Chem. Ber. 1993, 126, 1299. (3) Weber, L.; Kaminski, 0.; Stammler, H.-G.; Neumann, B.; Romanenko, V. D. Z. Naturforsch. 1993,48B, 1784. (4) Weber, L.; Kaminski, 0.;Stammler, H.-G.; Neumann, B.; Boese, R. 2.Naturforsch. 1994,49B, 1693.
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0 1995 American Chemical Society
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Communications
582 Organometallics, Vol. 14,No.2, 1995 Treatment of 1 with dimethyl acetylenedicarboxylate furnished a mixture of l-metallo-l-phospha-1,3-butadiene I1 and the metallaheterocycle III: whereas the synthesis of the condensation products V was achieved upon exposure of 1 to dialkyl azodicarboxy1ates.l The step from electron-deficient azo compounds to diazocarboxylates was obvious. Here we report on the chemical behavior of 1 toward ethyl diazoacetate (2a) and tert-butyl diazoacetate (2b), both of which are known as potent 1,3-dipoles. Treatment of a diethyl ether solution of 1 with a slight excess of the esters 2a,b at -30 "C afforded the products as yellow (3a)or red (3b)crystalline solids, respectively. The structure of 3a,b was assigned on the basis of spectral evidence5 and confirmed by the single-crystal X-ray diffraction study of 3b. The 31PNMR spectra exhibit a singlet resonance at 6 229.1 (3a) and 228.8 ppm (3b). These shifts compare well with the 6(31P) NMR shifts of the metal-free W-1,2,3-diazaphospholes 4 (R = Me, 6 228.9 ppm), 5 (R = Ph, 6 225 ppm), and 6 (R = 2-py, 6 228.1 ppmh6
r -12
[Fe]
[Fe]-N:
CmI
Figure 1. Molecular structure of 3b. Important bond lengths (A)and angles (deg) are as follows: Fe-C(cp*) = 2.120(3)-2.139(3), Fe-C(11) = 1.782(8),Fe-C(l2) = 1.770(9), Fe-N(l) = 1.953(6),P-N(l) = 1.703(6),P-C(14) = 1.746(8), C(13)-C(14) = 1.425(10),N(2)-C(13) = 1.346(8),N(l)-N(2) = 1.342(7),C(13)-C(17) = 1.488(10),N(3)C(14) = 1.390(9);Fe-N(1)-N(2) = 118.9(5),Fe-N(1)-P = 126.3(4),P-N(l)-N(S) = 114.7(5),N(l)-N(2)-C(13) = 111.1(7),N(2)-C(13)-C(14) = 116.2(7),N(l)-P-C(14) = 91.O( 4). cally Werent N-methyl groups and the C5Me5 protons in 3b and 3a, respectively. The ethyl group in 3a and the tert-butyl group in 3b gave rise to resonances at 6 1.18 (t,3 J =~7.1 ~ Hz), 4.31 (9,3 J =~7.1 Hz), and 1.62 (9) ppm, respectively. In the l3C(lH} NMR spectrum of the products the amino-substituted ring carbon atom is observed as a doublet a t 6 184.0 (Vpc = 50.4 Hz) (3a) or 183.5 ppm (~JPc = 50.2 Hz) (3b),respectively. A singlet a t 6 146.2 ppm in 3a and a doublet at 6 147.5 ( 2 J p ~= 9.2 Hz) ppm in 3b are attributed to the alkoxycarbonyl-functionalized ring carbons. The terminal carbonyl ligands cause a singlet at 6 214.0 ppm in 3a and a doublet at 6 215.1 (3Jpc = 5.1 Hz) ppm in 3b. The carbon atoms of the ester carbonyls are observed at 6 163.3 s (3a) and 6 162.8 (d, 3 J p = ~ 2.9 Hz) in 3b. In diazaphosphole 4 for comparison, doublets a t 6 135.3 (VPC= 35.4 Hz) and 155.7 ( 2 J=~ 8.8~Hz) ppm are due to the ring carbons C(4) and C(5).6 Complex 3a displays two intense v(C0) bands for the Fe(C0)2 groups at 2024 and 1972 cm-l, whereas the carbonyl stretch of the ester function gives rise to a band of medium intensity at 1695 cm-l. The most interesting feature of the molecular structure of 3b (Figure 1)'is the geometry of the heterocyclic ligand, which is attached to the iron center by an Fe-N single bond of 1.953(6)A. In low-valent iron carbonyl
YNMS \ t?*C\C02R
-$+In the lH NMR spectrum two singlets at 6 2.86 and 2.87 ppm and a singlet a t 6 1.27 (3b) or 1.28 ppm (3a) are readily assigned to the two chemically and magneti( 5 ) 3a: 1H NMR (300 MHz, c&) 6 1.18 (t, 3 J m= 7.1 Hz, CHgCiYd, 2.86 ( 8 , 3H, NCHs), 2.87 (8, 3H, NCHd, 4.31 1.27 [s, 15H, CS(CH~)~I, (9, 3 5 H H = 7.1 Hz, CHzCH3); '3C{'H} NMR (75 MHZ, CsDd 6 8.7 [S, C6(CH3)51, 14.7 ( 8 , CHZCH~), 47.3 ( 8 , NCHs), 47.45 ( 8 , NCHd, 59.5 ( 8 , CHZCHs), 97.8 (s,C5(CH&), 146.2 ( 8 , P 4 - 0 , 163.3 ( 8 , C02Et), 184.0 (d, lJpc = 50.4 Hz, P-C), 214.0 (s, FeCO); 31P{1H} NMR (40.5 MHz, c a s ) 6 229.1 s; MS (EI, 70 eV) mle 447 (19%, M+), 391 (loo%, M+ -2CO), 247 [37%, (C5Me5)(CO)zFe+l. 3 b 'H N M R (300 MHz, C6Dd 6 1.28 [s, 15H, C5(CH&I, 1.62 (s,9H, tBu), 2.86 (s,3H, NCHs), 2.87 ( 8 , 3H, NCH3); 13C{'H} NMR (75 MHz, C&) 6 8.7 [d, 4Jpc= 0.6 Hz, C5( m 3 ) 6 1 , 26.7 [s, C(CH3)31, 47.4 (s, NCHd, 47.6 (8, NCHd, 78.7 [S, C(CH&], 97.8 [s, C5(CH3)51, 147.5 (d, 'Jpc = 9.2 Hz, P-C-C), 162.8 (d, 3 J p c = 2.9 Hz, COztBu), 183.5 (d, 'Jpc = 50.2 Hz, P-), 215.1 (d, 3Jpc = 5.1 Hz, FeCO); 31P{1H}NMR (40.5 MHz, c&) 6 228.8 s; MS (EI, 70 eV) m/e 475 (25%, M+), 419 (45%, M+ - 2CO), 363 (loo%, M+ - 2CO - CHZ=CMez), 247 [21%, (C5Me~)(C0)2Fe+l.
(6) Weinmaier, J. H.; Brunnhuber, G.; Schmidpeter, A. Chem. Ber. 1980,113,2278. (7) Crystal data for complex 3b: space group P21/c, a = 11.3353) A, b = 17.273(5)A, c = 12.316(3) A, j3 = 90.87(2)", V = 2411.1(11) Z = 4, e = 1.309 g/cm3, Mo Ka (graphite monochromator, 1 = 0.710 73 $,w scan, data collection at 183 K (3" 4 20 d 50"); 4274 unique reflections Siemens P2(1) four-circle difiadometer, structure solved by direct methods and refinement by full-matrix least squares, using Siemens SHELXTL PLUWSHEXL-93. All non-hydrogen atoms were refined anisotropically with 258 parameters and 226 restraints (hydrogen atoms in calculated positions riding on the corresponding C atoms). RF = 0.089 and W&Q = 0.105 for 1771 reflections withFo > 4dF0) and maximum rest electron density 0.5 e/&.
a3,
Communications
Organometallics, Vol. 14,No. 2, 1995 583
complexes with nitrogen-containingligands Fe-N single bonds usually range from ca. 1.80 to 2.00 A.a The endocyclic ring distances N(l)-N(2) (1.342(7)A), P-N(l) (1.703(6)A), P-C(14) (1.746(8) A), N(2)-C(13) (1.346(8) A), and C(13)-C(14) (1.425(10) A) compare well with the corresponding parameters in 7 (1.34,1.68, The endocyclic 1.75, 1.34, and 1.44 A, respe~tively).~ angles at phosphorus in both compounds are determined to be 91.0(4)" (3b)and 89'. The Fe atom is located in the plane of the heterocycle, which encloses a dihedral angle with the plane defined by the atoms Fe, C(11), C(12), 0(1),and O(2) of 85.4'. The results reported here merit attention for several reasons. (1)1,3-Dipolarcycloadditionsof acyldiazoalkaneswith properly 1,2-functionalizedphosphaalkenes such as Me3Si-P = C(R1)(OSiMe3)or Cl-P=C(R1)(SiMe3) usually afford 1,2,4-diazaphospholes and not the 172,3-isomers described here.1° Diazoalkanes also add t o phosphaalkynes R2C=P (R2 = neopentyl, iPr, tBu, other tertiary alkyl groups) regiospecifically with the formation of a P-C bond. The regioisomeric 1,2,3-diazaphospholes, however, result as minor products from the cycloaddition of tert-butyl diazoacetate to HC=P12 or CF&H=N2 and N2=CH-C02Me to i P r 2 N - c ~ P . l ~ (2) The coordination chemistry of 1,2,3-diazaphospholes has been scarcely developed and features a few
P- and N-coordinated complexes where the ring invariantly donates two electrons via the respective lone pair.14 Compounds 3a,b are the first transition-metal derivatives of W-l,2,3-diazaphospholeswhere a 17-valenceelectron fragment is linked to the ring atom N(2) in place of an organic substituent. n Complexes of 1,2,3diazaphospholes are still unknown. The facile loss of two CO ligands in the mass spectra (E1 and CI) of 3a,b gives evidence for a facile o h rearrangement. Preliminary attempts, however, to reproduce this rearrangement on a preparative scale either in boiling xylene or by W irradiation failed. Investigations on the chemistry of 2-metallo-1,2,3diazaphospholes are underway.
(8) (a) Baikie, P. E.; Mills, 0. S. J. Chem. SOC.,Chem. Commun. 1966,707. (b) Doedens, R. J. Inorg. Chem. 1969,8,570; 1970,9,429. (c) Friihauf, H.-W.; Landers, A.; Goddard, R.; Kriiger, C. Angew. Chem. 1978, 90, 56; Angew. Chem., Int. Ed. Engl. 1978, 17, 64. (d) Berndt, A. F.; Barnett, K. W. J. Organomet. Chem. 1980, 184, 211. (9)Vilkov, L. V.; Khaikin, L. S.; Vasilev, A. F.; Ignatova, N. P.; Melnikov, N. N.; Negrebetskii, V. V.; Shvetsov-Shilovskii,N. I.; Dokl. Akad. Nauk SSSR 1971, 197, 1081 (cited in ref 10, p 281). (10) Schmidpeter, A.; Karaghiosoff, K. In Multiple Bonds and Low Coordination on Phosphorus Chemistry; Regitz, M., Scherer, 0. J., Eds.; Thieme: Stuttgart, Germany, 1990; p 258 and literature cited therein. (11)Regitz, M.; Binger, P. Angew. Chem. 1988, 100, 1541; Angew. Chem., Int. Ed. Engl. 1988,27, 1484. (12) Fuchs, E. P. 0.;Hermesdorf, M.; Schnurr, W.; Rb;sch, W.; Heydt, H.; Regitz, M.; Binger, P. J. Organomet. Chem. 1988, 338, 329. (13) Grobe, J.; LeVan, D.; Hegemann, M.; Krebs, B.; Lage, M. Chem. Ber. 1992, 125, 411.
(14) P-coordinated complexes 1,2,3-diazaphospholeshave been dePtscribed with C I ( C O ) ~ , ~W(CO)6,l5 ,~~ Fe(C0)4,15 Mn(Mecp)(CO)~,l~ (PPhS), (n = 2, 3),16 and ci~-PtClz(PEt3).'~ In a trans-PdClz(PEt3) complex the heterocycle is N-coordinated, whereas the reaction of afforded a 2:l [PtBrz(PEt~)lzwith 2,5-dimethyl-l,2,3-diazaphosphole mixture of the cis-P isomer and the trans-N isomer of PtBrz(PEt8).l7 In gold 1,2,3-diazaphosphole complexes N- or P-coordination is governed by the nature of the substituents at the heterocycle.1s ( 1 5 ) Weinmaier, J. H.; Tautz, H.; Schmidpeter, A. J. Organomet. Chem. 1980,185, 53. (16) Kraijkamp, J. G.; van Koten, G.; Vrieze, K.; Grove, D. M.; Hop, E. A.; Spek, A. L.; Schmidpeter, A. J. Organomet. Chem. 1983, 256, 375. (17) Kraijkamp, J. G.; Grove, D. M.; van Koten, G.; Schmidpeter, A. Inorg. Chem. 1988,27, 2612. (18)Dash, K C.; Schmidbaur, H.; Schmidpeter, A. Inorg. Chim. Acta 1980,41, 167.
Acknowledgment. Our work was generously supported by the Deutsche Forschungsgemeinschaft, Bonn, Germany, the Fonds der Chemischen Industrie, Frankfurt,Germany, and BASF AG, Ludwigshafen, Germany. This assistance is gratefully acknowledged. Supplementary Material Available: Tables of crystal data and structure refinement details, positional and thermal parameters, and bond distances and angles for 3b (7 pages). Ordering information is given on any current masthead page. OM940866B
