Organometallics 1995, 14, 1626-1631
1626
Transition-Metal-Substituted Acylphosphanes and Phosphaalkenes. 27.l Synthesis and Structure of q l:q2=MetallophosphaalkeneComplexes ( q5-C5H5)2(CO)2Fe2[(q5-CsMe4R)(C0)LM-P=CHSMe] (M = Fe, Ru, Mn; L = CO, NO; R = Me, Et) Lothar Weber,* Iris Schumann, Hans-Georg Stammler, and Beate Neumann Fakultat fur Chemie der Universitat Bielefeld, Universitatsstrasse 25, 0-33615 Bielefeld, Germany Received March 28, 1994@
The condensation of the p-carbyne complex [(r5-C5H5)2(C0)2~-CO)(p-CSMe)Fe21(S03CF3) (1)with metallobis(trimethylsily1)phosphanes [Ml-P(SiMe3)2 (2) (2a,[MI = (1;15-C5Me5)(C0)2Fe; 2b,[MI = (q5-C5MedC0)2Ru; 2c, (q5-C5Me5)(CO)(NO)Mn;2d, (r5-C5Me4Et)(C0)2Fe)in acetonitrile afforded p(q1:y2)-metallophosphaalkene complexes (r5-C5H5)(CO)2Fe2([M]-P= CHSMe} (3a-d). Similarly 3a results from the reaction of 1 and the complex (r5-C5Me5)(C0)2Fe-PH2. The compounds 3a-d were characterized by spectroscopic methods (IR, 'H, 13C,31PNMR, mass spectroscopy). The solid state structure of 3a was determined by a single crystal X-ray diffraction analysis (Pi, a = 9.445(5)A,b = 11.654(6)A, c = 15.732(9) A,a = 99.93(4)",/?= 103.09(4)",y = 105.58(4)").
Introduction Theoretical calculations2 and experimental evidence3 underline the pronounced instability of isophosphaalkynes R-PIC (isocyaphides) with respect to the more familar phosphaalkynes R-CEP.~ Recently Angelici et al. succeeded in the preparation of a first diplatinum complex I featuring a semibridging supermesitylisophosphaalkyne (supermesitylisocyaphide) ligand (eq l).5More recently we described an alterna-
Aryl P(H) W e 3
DBU
,Aryl
P
\\
Mes' L = PEt3
/p
-I
tive and complementary approach to p-isophosphaalkyne complexes which was based on the condensation of the (p-carbyne)diiron complex I with aryl(sily1)phosphanes (eq 2L6 The employment of metallodisilylphosphanes instead of aryl(sily1)phosphanes should provide a synthetic access to compounds I11 exhibiting the C=P
ligand in a novel mode of coordination. Two years ago the first cyaphide complex IV with a p(y1:y2) ligand arrangement was reported by Angelici et al.7 CI Et3P-Pt
Abstract published in Advance ACS Abstracts, February 15,1995. (1)Part 26: Weber, L.; Kaminski, 0.; Stammler, H.-G.; Neumann, B. Organometallics 1995, 14, 581. ( 2 )(a)Lehmann, K. K.; Ross, S. C.; Lohr, L. L. J . Chem. Phys. 1985, 82, 4460. (b) Nguyen, M. T.;Ha, T.-K.; J . Mol. Struct. Pi"heochem) 1986,139, 145. ( 3 )(a) Goede, S. J.;Bickelhaupt, F. Chem. Ber. 1991,124,2677. (b) Yoshifuji, M.; Niitsu, T.; Inamoto, N. Chem. Lett. 1988, 1733. (c) Markovskii, L. N.; Koidan, G. N.; Marchenko, A. P . ; Romanenko, V. D.; Povolotskii,M. I.; Pinchuk, A. M. Zh. Obshch.Khim. 1988,59,2133. ( 4 )(a)Becker, G.; Gresser, G.; Uhl, W. 2. Naturforsch. 1981, 36b, 16. (b) Regitz, M. Chem. Rev. 1990, 90,191. (c) Regitz, M.; Binger, P.;Angew.Chem. 1988,100,1541;Angew.Chem.,Int. Ed. Engl. 1988, 27, 1484. (d) Regitz, M. In Multiple Bonds and Low Coordination in Phosphorus Chemistry; Regitz, M., Scherer, 0. J., Eds.; Thieme: Stuttgart, Germany, 1990; p 58. ( 5 ) Jun, H.; Young, V. G.; Angelici, R. J. J . Am. Chem. SOC.1991, 113, 9379. Jun, H.; Angelici, R. J . Organometallics 1994, 13, 2454. ( 6 )Weber, L.; Schumann, I.; Schmidt, T.; Stammler, H.-G.; Neumann, B.; 2. Anorg. Allg. Chem. 1993, 619, 1759. @
I
I
--Et3
PEt J
Experimental Section General Information. Standard inert-atmosphere techniques were used for the manipulation of all reagents and reaction products. Infrared spectra were recorded on a Perkin( 7 )Jun,H.; Young, V. G., Jr.;Angelici, R. J . J . Am. Chem. SOC.1992, 114, 10064.
0276-733319512314-1626$09.00/0 0 1995 American Chemical Society
Metallophosphaalkene Complexes
Organometallics, Vol. 14, No. 4, 1995 1627
(30%) of dark-green microcrystalline 3b was obtained as Elmer Model 580 spectrometer. UV/vis spectra were obtained described before. with a modified Omega UV/vis spectrometer. 'H, 13C,and 31P NMR spectra were taken on a Bruker AM 400, Bruker AM IR (KBr, cm-'1: Y 2981 w, 2912 m, 2013 s [v(CO)], 1960 s 300, or Bruker AC 100 spectrometer in C& solution at room [v(CO)I, 1920 s [Y(CO)I,1754 s [v(CO)I,1698 w, 1631 m, 1487 temperature. Mass spectra were measured on a Finnigan w, 1456 w, 1422 w, 1385 m, 1364 w, 1307 w, 1158 w, 1112 w, MAT MS 311A (EI-mode, 80 eV). 1073 m, 1028 m, 957 s, 848 w, 818 w, 668 w, 630 w, 582 m, 556 s, 538 s, 522 s, 504 s, 474 m. IR (toluene, Y(CO),cm-l): Materials. All solvents were rigorously dried with an Y 2016 s, 1965 s, 1919 s, 1783 s. U V l v i s (toluene) [Amm (log appropriate drying agent and distilled before use (e.g. CH3CN E)]: 370 (3.89), 550 (2.50) nm. 'H NMR (CsDs): 6 1.40 ( 8 , lH, according to ref 8). The metallophosphanes (q5-C5Me5)(CO)2~ 1.9 ~ Hz, 15H, Cs(CHs)a), 1.83 (d, 4 J p ~= CHI, 1.59 (d, 4 J = FeP(SiMe3)2,9 (q5-C5Me5)(CO)2RuP(SiMe&,'0 (q5-C5Me5)(CO)1.4 Hz, SCH3), 4.34 (d, 3 J p = ~ 1.3 Hz, 5H, C5H5), 4.73 (d, 3 J p ~ and (q5(NO)MnP(SiMe&,'l (q5-C5EtMe4)(C0)2FeP(SiMe3)2,l2 = 0.6 Hz, 5H, C5H5). 13C{'H} NMR (CsDs): 6 9.6 (s,C5(CH3)5), C&e5)(CO)zFePH2l3 and the carbyne complex [(q5-C5H5)2(C0)220.4 (d, Vpc = 6 Hz, SCH3), 50.2 (d, ' J p c = 43 Hz, P=C), 81.6 Fe(u-CO)(u-CSMe)IfS03CF3- l4 were prepared as described in (s,C a ) , 83.7 (9, C A ) , 101.4(9, C5(CH3)5),200.8 (9, Cp*RuCO), the literature. 1,8-Diazabicyclo[5.4.0lundec-7-ene (DBU) and 201.7 (d, 'Jpc = 11 Hz, Cp*RuCO), 219.8 (d, 2 J p c = 24 Hz, silica gel 60, silanized, 70-230 mesh ASTM (Merck), were CpFeCO), 257.6 (s, p-co). 31P{1H}NMR (CsDs): 6 264.0 s. obtained commercially. MS: mle 682 (M+),654 (M+ - CO), 626 (M+ - 2CO), 583 (M+ Preparation of Compounds: (115-CaH~)~(CO)~e~I(~s-C~- 3CO - CH3), 555 (M+ - 4CO - CH3), 186 (Cp,Fe+), 121 Me5)(CO)zFe-P=CHSMe] (3a). Path A. A sample of 0.46 (CpFe+). Anal. Calcd for CzsH2~Fez04PRuS(681.32): C, 45.84; g (1.09 mmol) of solid 2a was added to a solution of 0.58 g H, 4.29. Found: C, 45.57; H, 4.20. (1.09 mmol) of 1 in 30 mL of acetonitrile at 0 "C. After the (qs-CsH5)z(CO)zFez[(;rlS-C5Me~)(CO)(NO)Mn-P= solution was stirred for 15 min at 0 "C, 0.23 g (1.52 mmol) of CHSMe] (3c). Analogously, 0.10 g (30%)of microcrystalline DBU was added, whereupon the color of the mixture imred-brown 3c was synthesized from 0.24 g (0.56 mmol) of 1, mediately changed to reddish-brown. Stirring was continued 0.30 g (0.56 mmol) of 2c, and 0.12 g (0.79 mmol) of DBU in 20 at ambient temperature for another 3 h. After evaporation to mL of acetonitrile. dryness the oily brown residue was chromatographed on silanized silica gel. The product was eluted as a dark red zone IR (KBr, cm-l): 2962 m, 2920 m, 1984 s [v(CO)], 1925 sh with a hexanelether mixture (15). The elute was freed from [v(CO)], 1748 s, br [v(CO), v(NO)I, 1630 m, 1429 m, 1384 m, volatiles, and the residue was crystallized from toluene/ 1269 m, 1015 m, 961 m, 842 m, 672 m, 579 m. IR (toluene, cyclopentane at -30 "C. After 24 h 0.20 g (28%) of deep-red cm-l): 1994 s, 1919 s, 1783 s [v(CO)I, 1734 s, [v(NO)I. UV/vis crystalline 3a was isolated. (toluene): ,A (log E): 328 (4.00) nm. 'H NMR (CsDs): 6 1.37 (d, 2 J p = ~ 1.2 Hz, l H , CHI, 1.53 (d, 4 J p = ~ 0.5 Hz, 15H, C5Path B. A sample of 0.51 g (1.82 mmol) of (q5-C5Me5)(C0)2~ 1.5 Hz, 3H, SCH3), 4.40 (d, 3 J= ~ 1.1 ~ (CH3)5), 1.80 (d, 4 J p = Fe-PH2 was added to a solution of 0.97 g (1.82 mmol) of 1 in Hz, 5H,C5H5), 4.82 (d, 3 J p ~= 0.3 Hz, 5H, C5H5). W{lH}30 mL of acetonitrile at 0 "C. After stirring of the solution for NMR (C&): 6 9.7 (s, C5(CH3)5),20.8 ( 8 , br, SCH& 55.8 (d, 10 min at 0 "C, 0.39 g (2.55 mmol) of DBU was added, where 3 J p c = 49 Hz, P-C), 81.6 (s, C5H5), 84.5 (s, C5H5), 104.4 (9, upon the color of the mixture changed from red to reddishCs(CH&), 219.7 (d, 2 J p ~= 23 Hz, CpFeCO), 233.1 (s, br, brown. An analogous workup led to the isolation of 0.45 g Cp*MnCO),257.2 (s, y-CO). 31PNMR (CsDs): 6 312.0 s. MS/ (39%) of 3a. FD: m/e 637 (M+). Anal. Calcd for C25HzsFezMnN04PS IR (KBr, cm-'1: 2963 m, 2909 m, 1997 s [v(CO)I, 1952 s (637.18): C, 47.13; H, 4.59; N, 2.20. Found: C, 46.87; H, 4.95; [v(CO)],1917 s [v(CO)],1762 s [v(CO)],1429 m, 1379 m, 1262 N, 2.47. m, 1129 m, 1025 m, 816 m, 668 m, 580 s, 501 m. IR (toluene, (~S-C~H~)z(CO)zFe~[(~s-C~e4Et)(CO)~Fe-P~CHSMel v(CO), cm-'1: 2002 s, 1955 s, 1920 s, 1783 s. UV/vis (toluene) (3d). Analogously to the synthesis of 3a, 0.14 g (35%) of [Amm (log E)]: 339 (3.971, 430 (3.56) nm. 'H NMR (CsDs): 6 microcrystalline brown 3d was prepared from 0.33 g (0.62 1.38 (d, 'JPH = 1.6 Hz, l H , CHI, 1.50 (d, 4 J p = ~ 1.0 Hz, 15H, mmol) of 1, 0.27 g (0.62 mmol) of 2d, and 0.13 (0.86 mmol) of ~ 1.5 Hz, 3H, SCHs), 4.37 (d, 3 J p = ~ C5(CH3)5), 1.83 (d, 4 J p = DBU in 20 mL. of acetonitrile. 1.0 Hz, 5H, C5H5), 4.74 (d, 3 J p = ~ 0.5Hz, 5H, C5H5). W('H} NMR (CsDs): 6 9.5 (d, 3 J p c = 2 Hz, c5(CH3)5), 20.6 (d, 3 J p c = IR (KBr, cm-'1: 2966 m, 2914 m, 1998 s [v(CO)I, 1956 s 5 Hz, SCHs), 55.6 (d, ' J p c = 49 Hz, P-C), 81.7 (8, C5H5), 84.4 [v(CO)I,1920 sh [v(CO)I,1768 s [v(CO)I, 1631 m, 1457 m, 1429 m, 1383 m, 1308 m, 1261 m, 1012 m, 813 m, 671 m, 580 s. IR (s, C5H5), 98.1 (s, C5(CH&), 215.0 (d, 2 J= ~ 13 Hz, ~ Cp*FeCO), 216.3 (d, 'Jpc = 18 Hz, Cp*FeCO), 219.6 (d, 2 J p ~= 25 Hz, (toluene, v(CO), cm-': 2002 s, 1955 s, 1920 s, 1782 s. UV/vis CpFeCO), 257.3 (s, p-co). 31P{1H}NMR (CsDs): 6 301.7 s. (toluene) [A,,.,= (log E ) ] : 315 (4.061, 400 (3.69) nm. 'H NMR MS: mle 636 (M+),608 (M+ - CO), 580 (M+ - 2CO), 537 (M+ 7.6 HZ, ~ 3 H, CH2CH31, 1.39 (d, 'JPH (CsDs): 6 0.75 (t, 3 J= ~ - 3CO - CH3), 509 (M+ - 4CO - CH3), 186 (CpzFe'), 121 = 1.2 Hz, lH, CHI, 1.51 (d, 4JPH = 0.6 Hz, 3H, CH3-3 or 41, (CpFe+). Anal. Calcd for C~&sFe304PS (636.09): C, 49.09; 1.53 ( 6 , 3H, CH3-3 or 41, 1.56 (s, 3H, CH3-2 or 5), 1.58 (s, 3H, H, 4.60; Fe, 26.34. Found: C, 48.95; H, 4.82; Fe, 27.02. CH3-2 or 5), 1.83 (d, 4JPH = 1.3 Hz, 3H, SCHs), 2.11 (qd, 3 J ~ ~ ~ 1.2 Hz, 2H, CHZCH~), 4.38 (d, 3JpH = 0.5 Hz, ( ~ 5 - C a H s ) ~ ( C O ) z F e z [ ( ~ 5 - C ~ e ~ ) ( C O(3b). ) z R u l = 7.5 Hz, 4 J p = 5H, C5H5), 4.74 (s, 5H,C5H5). 13C{lH}NMR (C6Ds): 6 9.3 (s, The solution of 0.46 g (0.97 mmol) of 2b and 0.52 g (0.97 mmol) CH3-3,4),9.5 (9, CH3-2,5), 14.3 (d, 4 J p = ~ 8 Hz, CHZCH3), 18.4 of 1 in 30 mL of acetonitrile was stirred at ambient temper(s, CHZCH~), 20.7 (d, 3 J p c = 4 Hz, SCHd, 55.8 (d, 'JPC = 49 ature for 30 min. Then 0.20 g (1.36 mmol) of DBU was added. Hz, P-C), 81.8 (s, C5H5), 84.5 (s, C~HS), 97.5 (s, CdCH)3)-3or After 3 h of stirring the mixture was freed from volatiles to 41, 97.6 (8, C5(CH3)-3 or 4) 98.6 (s, CdCH3)-2 or 51, 99.0 (s, give a greenish brown residue. Column chromatography on Cs(CH3)-2 or 5), 102.5 (s, C5(CzH5)), 215.0 (d, 2 J p c = 13 Hz, silanized silica gel with hexanelether (51)and hexane/ether (CsEtMed)FeCO),216.3 (d, Vpc = 18 Hz, (CsEtMe4)FeCO), (1:l) as eluents furnished a green fraction, from which 0.20 g ~ 24 Hz, CpFeCO), 258.1 (s,y-CO). 31{1H}NMR 219.9 (d, 2 J p = (CsDe): 6 300.0 8. MS: mle 650 (M'), 622 (M+ - Co), 594 (8)Christe, K. 0.; Dixon, D. A.; Mahjoub, A. R.; Mercier, H. P. A.; Sanders, J. C. P.; Seppelt, R;Schrobilgen, G. J.; Wilson, W. W. J.Am. (M+ - 2CO), 551 (M+ - 3CO - CH3), 523 (M+ - 4CO - CH3), Chem. SOC.1993,115,2696. 186 (CpzFe+), 121 (CpFe+). Anal. Calcd for C27H31Fe304PS (9)Weber, L.;Reizig, K.; Boese, R. Chem. Ber. 1988,118,1193. (650.12): C, 49.88; H, 4.81; Fe, 25.77. Found: C, 50.06; H, (10)Weber, L.;Reizig, K.; Boese, R.; Organometallics 198S,4 , 2097. 4.88; Fe, 25.84. (11)Weber, L.;Meine, G.; Chem. Ber. 1987,120,457. (12)Weber, L.; Schumann, I.; Stammler, H.-G.; Neumann, B. 2. X-ray Structure Determination of sa. Dark red crystals Naturforsch. 1992,47b, 1134. of 3a were grown from a solution in toluenekyclopentane at (13)Weber, L.;Kirchhoff, R.; Stammler, H.-G.; Neumann, B. Chem. -40 "C. An irregularly shaped crystal of the approximate Ber. 1992,125,1553. dimensions 0.60 x 0.15 x 0.10 mm was coated with a layer of (14)Quick, M.H.;Angelici, R. J. Inorg. Chem. 1981,20, 1123.
Weber et al.
1628 Organometallics, Vol. 14, No. 4, 1995
Scheme 1
the 31PNMR data of the arylisophosphaalkyne complex I1 (6 249.3-258.016 and would be consistent with the anticipated formation of 111. On the grounds of lH and D/ 13CNMR evidence, however, this assumption had to be discarded. Doublets which would correspond to the carbon atom of the C=P moiety of hypothetical I11 were absent in the low-field region of the spectra (in I1 they 0 SMe were registered at 6 333.8-345.8). Instead doublets at 6 50.2-55.8 P J p c = 43-49 Hz) in the J-modulated 13C NMR spectra are in agreement with the situation of a n-bonded P=CH unit. As later confirmed by an X-ray study of 3a the dinuclear iron complexes 3a-d were formed, displaying p-(y1:y2)-ligatedmetallophosphaalkenes of the type [MI-P=CHSMe. With respect to the low-field 31P-resonancesof related metallophosphaalkenes such as (v5-C5Me5)(C0)zFe-P=C(SiMe3)2(6 = 641.5),15(rl5-CsMesXC0)2Fe-P(Ph)SiMe3 (6 = 520.0),16 30-d and (v5-C5Me5)(C0)zFe-P=C(SSiMe3)2 (6 = 503.8)17 (the free metallophosphaalkenes [MI-P=CHSMe are unknown), the 31PNMR data of 3a-d are also in accord with an v2-phosphaalkene ligand featuring the familiar hydrocarbon oil, attached to a glass fiber, cooled to 173 K for high-field shifts upon n-coordination. The 2 J p c coudata collection, and mounted on a Siemens P21 four-circle plings (23-25 Hz) of the remaining terminal carbonyl I diffractometer (Mo Ka radiation, graphite monochromator, , ligand at the CpFe building block (6 219.6-219.9) = 0.710 73 A). The cell dimensions were determined by indicate an intense Fe-P interaction. In I1 the terminal refinement of the s?tting angles of 30 reflections (4" < 28 < CO groups gave rise to absorptions at much higher field 25"): a = 9.445(5) A, b = 11.654(6) A, c = 15.732(9)A, a = (6(13C)209.9-211.0). This observation is in accord with 99.93(4)",fi = 103.09", y = 105.58", V = 1537(2)A3. The space a considerable charge transfer from the metallophosgroup was established to be Pi (2= 2, Dealc= 1537 mg/m3, p = 1.518 mm-') with w-scan data collection of 7225 independent phaalkene to the Cp(C0)Fe unit in 3a-d. Singlets at intensities (3" 28 < 55"). The structure was solved by direct 6 257.2-258.1 were attributed to the p-CO ligand. methods, successive difference Fourier maps, and full-matrix These signal are markedly shielded as compared to the least-squares cycles. The crystallographic programs applied related resonances in I1 (6(13C) 269.2-270.8). The were SHELXS-86/SHELXL-93 using intrinsic scattering faccarbonyl resonances of the ligands incorporated in the tors. All non-hydrogen atoms were given anisotropic displace[MI in 3a-d are well comparable with the fragment ment parameters; all the hydrogen atoms were fxed at corresponding absorptions in the metallodiphosphenes calculated positions. The R values based on the final model [6 = 216.3 (d, 2 J p ~= 11.9 refined with 379 parameters were RF = X(IFoI- IFcl)/Z(I~ol) Cp*(C0)2Fe-P=P-Mes* Hz)I,'* Cp*(CO)zRu-P=P-Mes* [6 = 202.1 (d, 2 J p = ~ = 0.0949 and Ruvp= [CwFo2 - Fc2)2/cFo2]1i2 = 0.2253, based 13.9 Hz)1,18 and Cp*(CO)(NO)Mn-P= on 4185 reflections with F, > 4dF,). The maximum residual electron density was 1.4 elA3, 1.03 A from Fe(3). P-Mes* (6 = 233.4 m).ll The presence of the S-CH3 group in 3a,b,d is ascertained by doublets at 6(13C) Results and Discussion 20.4-20.7 ( 3 J p ~= 4-6 Hz) and a broad singlet at 6The reaction of the p-carbyne complex 1 with equimoP3C)20.8 for 3c. The lH NMR spectrum shows doublets lar amounts of the metallodisilylphosphanes 2a-d in at 6 1.80-1.83 (*JpH = 1.3-1.5 Hz) for this functionality. the presence of DBU afforded microcrystalline deeply The proton at the C=P bond in 3a,c,d is detected as a colored solids, which were isolated by column chroma~ 1.2-1.6 Hz) and as a doublet at 6 1.37-1.39 ( 2 J p = tography and subsequent crystallization (Scheme 1). singlet at 6 = 1.40 in 3b. In complex 4 a doublet at 6 The course of the reaction was conveniently monitored by 31P NMR spectroscopy. The high-field singlets of 2a-d (6 -202.9 to -219.9) were replaced by singlets at 6 264.0-312.0. These resonances compare well with [MI
1'
-
(15) Gudat, D.; Niecke, E.; k i f , A. M.; Cowley, A. H.; Quashie, S. Organometallics 1986, 5 , 593. (16) Niecke, E.; Metternich, H.J.; Nieger, M.; Gudat, D. Wenderoth, P.; Malisch, W.; Hahner, C. Reich, W. Chem. Ber. 1993, 126, 1299. (17) Weber, L.; Tonviehe, B. Unpublished results. (18)Weber, L.; Reizig, K.; Bungardt, D.; Boese, R. Organometallics 1987, 6, 110. (19) Weber, L.; Lucke, E.; Boese, R.; Chem. Ber. 1990, 123, 23. (20)Appel, R.; Casser, C.; Knoch, F. J. Organomet. Chem. 1985,293, 213. (21) Holand, S.; Charrier, C.; Mathey, F.; Fischer, J.; Mitschler, A. J . Am. Chem. SOC.1984,106,826. (22) Knoll, K.; Huttner, G.; Wasciucionek, M.; Zsolnai, L. Angew. Chem. 1984,96, 708; Angew. Chem., Int. Ed. Engl. 1984,23, 739. (23)Adelt, S.; Bitterer, F.; Fischer, J.; Rothe, J.; Stelzer, 0.; Sheldrick, W. S. Chem. Ber. 1992, 125, 1999. (24) Williams, G. D.; Geoffrey, G. L.; Whittle, R. R.; Rheingold, A. L.; J . Am. Chem. SOC.1985, 107, 729. (25)Appel, R.; Krieger, L. J. Orgunomet. Chem. 1988, 354, 309. (26)Niecke, E.; Leuer, M.; Nieger, M. Chem. Ber. 1989, 122, 453. (27) Karsch, H. H. Personal communication.
w OC-Fe
4 -
0.35 ( 2 J p ~= 2.5 Hz) accounts for the proton at the n-bonded organophosphorus ligand.lg In the IR spectra of the complexes 3a,b,d (toluene solution) the carbonyl stretching vibrations give rise t o three intense bands at 2013-1919 cm-l for the terminal CO groups and one intense band at 1752-1783 cm-l for the bridging carbonyl. In 3c the NO stretching vibration is assigned to a strong absorption at 1734 cm-l. X-ray Structure Analysis of 3a. Single crystals of 3a suitable for an X-ray analysis were grown from
Metallophosphaalkene Complexes
Organometallics, Vol. 14,No. 4,1995 1629 Table 2. Selected Bond Lengths (A) and Angles (deg) for 3a
Figure 1. Table 1. Atomic Coordinates ( x 104) and Equivalent Isotropic Displacement Parameters V(iso) or U(eq)l (A2 x 103) for 3a X
1850(1) 4275(1) 3937(1) 7351(3) 3801(2) 3322(8) 2766(9) 6805(8) 1896(9) 148(12) -305( 11) -397(9) O( 10) 352(11) 3577(12) 4821(11) 6092(11) 5688(13) 4133(13) 3418( 11) 2468( 11) 5429( 10) 7976( 12) 5657( 11) 271 l(11) 2423(11) 2895( 11) 4502( 11) 501l(11) 3701(12) 771(14) 1883(14) 5492(12) 6605(14) 3682( 17) 8393(14) 6877(13) 6329(14) 7289(16) 8768(14) 9334(13) 9030(16)
Y
Z
2432( 1) 2502(1) 5933(1) 4626(2) 4084(2) 493(6) 2697(7) 6232(6) 47 lO(7) 920(9) 1193(9) 2399(9) 2845(9) 1939(9) 1990(11) 3079(9) 2885(9) 1645(10) 1089(9) 1379(8) 2622(8) 37 1O(7) 5 110(10) 6052(8) 5179(8) 6543(8) 7332(8) 7858(7) 7406(8) 6606(8 ) 5912(11) 7596(10) 8793(9) 7835(10) 6001( 10) 1111(9) 1056(10) 1320(11) 1677(10) 1731(12) 1459(12) 784( 11)
7102(1) 6548( 1) 6931(1) 8040(2) 7233( 1) 7370(5) 9029(5) 6459(5) 5109(5) 6144(7) 6921(7) 7026(6) 6302(6) 5768(6) 5103(6) 5417(6) 5971(6) 6015(7) 5488(7) 71 lO(6) 8283(6) 7828(6) 9259(6) 6655(6) 5823(6) 7556(7) 6983(6) 732 1(6) 8094(6) 8228(6) 7508(11) 6208(8) 6973(7) 8700(7) 899 l(7) IO53 l(7) 10216(8) 94 1O( 9) 8900(8) 9168(7) 9976(8) 11399(8)
U(es)
Fe( 1)-C( 12) Fe( 1)-C( 2) Fe( 1)-C(3) Fe( 1)-C( 1) Fe( 1)-C(4) Fe( 1)-C(5) Fe( l)-C(11) Fe( 1)-P( 1) Fe( 1)-Fe(2) Fe(2)-C(ll) Fe(2)-C(9) Fe(2)-C( 10) Fe(2)-C( 13) Fe(2)-C(8) Fe(2)-C(6) Fe(2)-C(7) Fe(2)-P( 1) Fe(3)-C( 15) Fe(3)-C( 16) Fe(3)-C( 19) Fe(3)-C( 17) Fe(3)-C(20) Fe(3)-C( 18) Fe(3)-C(2 1) Fe(3)-P( 1) S(1)-C(13) S(l)-C(14) P( 1)-C( 13) O(1)-C( 11) O(2)-C( 12) O(3)-C( 15) 0(4)-C( 16)
1.771(10) 2.080( 10) 2.088(9) 2.104(10) 2.129(9) 2.130(10) 2.162(9) 2.22 1(3) 2.616(2) 1.818(9) 2.101(9) 2.085(9) 2.104(9) 2.098(8) 2.144( 10) 2.128(8) 2.177(3) 1.752(9) 1.778(10) 2.105(8) 2.111(8) 2.113(9) 2.1 18(9) 2.138(9) 2.26 l(3) 1.764(9) 1.811(10) 1.812(9) 1.163(10) 1.126(11) 1.168(11) 1.150(11)
C(l2)-Fe(l)-C(ll) C( 12)-Fe( 1)-P(l) C( 11)-Fe( 1)-P(l) C( 12)-Fe( 1)-Fe(2) C(l l)-Fe(l)-Fe(2) P( 1)-Fe( 1)-Fe(2) C( 1l)-Fe(2)-P( 1 ) C( 13)-Fe(2) -P( 1) C( ll)-Fe(2)-Fe( 1) C( 13)-Fe(2)-Fe( 1) P( l)-Fe(2)-Fe( 1) C( 15)-Fe(3)-C( 16) c(13)-s( 1)-c(14) C( 13)-P(l)-Fe(2) C( 13)-P( 1)-Fe( 1) Fe(2)-P( 1)-Fe( 1) C( 13)-P( 1)-Fe(3) Fe(2)-P( 1)-Fe(3) Fe(1)-P( 1)-Fe( 3) O(1)-C( 11)-Fe(2) O(1)-C(l1)-Fe(1) Fe(2)-C(ll)-Fe(l) 0(2)-C( 12)-Fe(1) S( l)-C(13)-P(l) S(1)-C( 13)-Fe(2) P( 1)-C( 13)-Fe(2) 0(3)-C( 15)-Fe(3) O(4)-C( 16)-Fe(3)
ligands in dinuclear complexes (e.g. in tiz0and 621).
pMe
Me
Mes' \
(W5W
J
w-0)5
5 =
Here, however, unlike in 3a-d a direct metal-metal linkage is absent. In cluster-stabilized phosphaalkenes 722and 8,23the phosphorus atom also bridges two metal centres, whereas the P-C n-bond interacts with a third iron atom. R 1
Ph 1
" U(eq) is defined as one-third of the trace of the orthogonalized U,, tensor.
toluene/cyclopentane solutions at -40 "C. The analysis displays the picture of a metallophosphaalkene which serves as a bridging g1:g2-ligandtoward the Cpz(C0)2Fez moiety (Figure 1;Tables 1and 2). Such a coordination mode of metallophosphaalkenes is novel. Metalfree phosphaalkenes may well interact as p-(v1:y2)-
82.7(4) 89.3(3) 87.9(3) 105.7(3) 43.5(2) 52.74(7) 98.8(3) 50.0(2) 54.9(3) 82.9(2) 54.27(7) 95.8(4) 101.8(5) 62.9(3) 102.2(3) 72.98(9) 124.3(3) 131.65(11) 133.06(11) 152.3(7) 125.8(7) 81.7(3) 175.5(9) 123.5(5) 118.9(4) 67.1(3) 174.1(8) 178.3(8)
1
Ph
Ph
Weber et al.
1630 Organometallics, Vol. 14, No. 4, 1995 Two different iron-phosphorus bonds [Fe(l)-P(l) = 2.221(3), Fe(2)-P(1) = 2.177(3) AI and an iron-carbon 1underline the unsymbond [Fe(2)-C(13) = 2.104(9) 8 metrical ligation of the P-C moiety of the metallophosphaalkene to the Fe-Fe unit. The u/n coordination is accompanied by an elongation of the P=C bond to 1.812(9)A. In free phosphaalkenes P-C double bonds range from 1.65 to 1.72 A, whereas P=C distances in 5 and 7-gZ4 amount to 1.737(6), 1.76(1), 1.772(4), and 1.800(6)8,respectively. The Fe-Fe bond in 3a [2.616(2) A] is similar to the metal-metal separation in 1 (SEt instead of SMe) [2.510(2) All4 or I1 [2.527(5) AI6 and those found in clusters 8 and 9 [2.671(2)-2.750(1) 81. The (2)-configurated organophosphorus ligand is distorted from planarity as evidenced by the torsion angle Fe(3)-P(l)-C(l3)-S(l) [-13.3"l. The CpzFez unit possesses a nearly linear terminal CO ligand at FeU) [Fe(l)-C(12) = 1.771(10) 8,Fe(l)-C(12)-0(2) = 175.5(9)"],whereas the second ligand is a semibridging 1and one with a short Fe(2)-C(11) contact [1.818(9)8 a markedly longer Fe(l)-C(ll) bond [2.162(9) 81. In keeping with this, the bond angles Fe(2)-C(ll)-O(l) = 152.3(7)" and Fe(l)-C(ll)-O(l) = 125.8(7)' differ significantly. Both cyclopentadienyl rings are synconfigurated. The metric parameters of the (CsMe5)(C0)zFe fragment which is linked to P(1) via a Fe-P single bond [2.261(3)AI are as expected. With respect t o the spectroscopic and structural data the bonding situation in 3a may be described by the canonical structures A-C.
Discussion. It is conceivable that the formation of compounds 3 is initiated by the nucleophilic attack of metallo(sily1)phosphide{ P(SiMe3)[Ml}- (VIat the carbyne bridge of 1 to give the p-alkylidene complex VI (Scheme 2). Compounds such as VI were detected as intermediates during the formation of 11. The replacement of the Me3Si group at phosphorus in VI by hydrogen was unexpected. Hydrolysis by traces of moisture can be excluded as the reaction vessels were flame-dried. The acetonitrile and trideuterioacetonitrile used as solvents were dried by refluxing over P4010as described by Christe et aL8 With CD3CN as a solvent no incorporation of deuterium in 3a was observed. DBU was treated with potassium metal before use. Thus the source of the hydrogen may be DBU itself. This is in line with findings where the acidic methylene group in the a-position of the imino carbon of DBU was involved in a condensation reaction with Mes*PClz to give Moreover one of these a-hydrogens of DBU was substituted by a phosphiranyl group when treated with 7 C ~ P C ( S I M ~ ~ ) Z C H The S~M attempted ~ ~ . ~ ~ dehydrochlorination of (Me3Si)zCHPClz by means of DBU surpris-
Scheme 2 [ M]-P(SiMe3)2
DBU
- (DBUSIMe3)+
am
MejSi
\ /
[MI
P
\ /
+ DBU
cp\ /
oc
SMe
c,\
Fe
-Fe\ \/ I/
cO
I
SIMe3
I-co
-1,Z
H
,
ingly afforded the condensation product 1Lz7 Thus it is reasonable that VI is desilylated by DBU and that the cation [DBU.SiMe31+ is deprotonated by the generated metallophosphide. An intramolecular replacement of CO by the phosphine function results in VIII. A 1,2 hydrogen shift and a second Fe-P contact leads to the final product. It is worth mentioning that the formation of 3 failed when NEt3 was used instead of DBU.
n
p\
10 -
Mes*
In a control experiment 1,(775-C5Mes)(CO)~Fe-PH~ and DBU afforded 3a in a slightly better yield (39%instead of 28%). The difference in the reactivity of arylPH(SiMes) or arylPHz and [MI-PH(SiMes) or [MI-PHz towards 1 may be rationalized by regarding the common intermediate VI. Obviously activation by the aryl group at phosphorus promotes 1,2 elimination of MesSiSMe or HSMe to give 11,whereas the electron donating metal group enhances the phosphane nucleophilicity facilitating intramolecular CO displacement instead of 1,2elimination. In VI11 the P-H bond at the tetracoordinate phosphorus atom is acidified enough to allow the
Metallophosphaalkene Complexes
1,2 H-shift from phosphorus t o carbon yielding p-(qJ: v2)-metallophosphaalkene complexes 3a-d as final products.
Acknowledgment. This work was generously SUPported by the Deutsche Forschungsgemeinschaft, Bonn, the Fonds der Chemischen Industrie, Frankfurt, the
Organometallics, Vol. 14, No. 4, 1995 1631
BASF AG, Ludwigshafen, and the DEGUSSA AG, Hanau, which is gratefully acknowledged. Supplementary Material Available: Tables of crystallographic data collection parameters, bond lengths and angles, anisotropic thermal parameters, and H coordinates and U values (7 pages). Ordering information is given on any current masthead page. OM9402451
