Organometallics 1995,14, 4446-4448
4446
P-FunctionalizedCyclic Phosphinidenemetallophosphoranes
c~(co)~W-P(X)(~.B~)-P(~-B~) (x = ci, H):
Direct Formation from Metallophosphines and Transformation Reactions Bernd K. Schmiedeskamp,t Joachim G. Reising,? Wolfgang Malisch,*p’ Kathrin Hindah1,t Rudolf Schemm,? and William S. Sheldrickt Institut fur Anorganische Chemie der Universitat Wurzburg, Am Hubland, 0-97074 Wiirzburg, Germany, and Lehrstuhl fur Analytische Chemie der Ruhruniversitat Bochum, Universitatsstrasse 150, 0-44780Bochum, Germany Received May 23, 1995@ Summary: The functionalized tungsten phosphines Cp(C0)3WP(X)-t-Bu (la,X = Cl; lb, X = H) convert in a controlled manner to the cyclized phosphinidenemetal-
-
lophosphoranes Cp(CO)2W-P(X)(t-BuI-P)t-Bu)(2a,X = Cl; 2b, X = H), which have been structurally determined by X-ray analysis. 2b can be transformed to Cp-
(CO)2W-P(t-Bu)(R)-P(t-Bu)(4a,R
= Me; 4b, R = CH2CH=CH2) via lithiation followed by alkylation. 4a is quaternized with methyl iodide to give the cationic 4diphosphine complex (Cp(CO)~4-Me(t-Bu)P-P(t-Bu)MeIw)I (5).
Metallophosphines of the type Cp(CO)3M-PRz are characterized by a high Lewis basicity, which guarantees their facile quaternization, oxidation, and coordination.2 In the case where bulky organic groups are attached at phosphorus, a high tendency for the formation of the corresponding phosphenium complexes Cp(C0)zM-PRz (R = t-Bu, Mes) is ~ b s e r v e darising ,~ from an intramolecular ligand exchange, leading to CO elimination. These kinds of complexes, conceivable as phosphorus analogues of carbene c~mplexes,~ represent, due to the high reactivity of the M=P bond, excellent starting materials for the generation of phosphametalla cycle^.^?^ In keeping with studies concerning the transformation of metallophosphines into M=P com~
~
Universitat Wiirzburg. Ruhruniversitat Bochum. @Abstractpublished in Advance ACS Abstracts, September 1, 1995. (1)Phosphenium TransitionMetal Complexes. 34. Part 3 3 Malisch, W.; Hahner, C.; Gnin, K.; Reising, J.;Goddard, R. Inorg. Chim. Acta, in press. (2) (a) Malisch, W.; Maisch, R.; Colquhoun, I. J.; McFarlane, W. J . Organomet. Chem. 1981, 220, C1. (b) Maisch, R.; Ott, E.; Buchner, W.; Malisch, W. J. Organomet. Chem. 1986,286, C31. (3)(a) Malisch, W.; Jorg, K.; Hofmockel, U.;Schmeusser, M.; Schemm, R.; Sheldrick, W. S. Phosphorus Sulfur Relat. Elem. 1987, 30, 205. (b) Malisch, W.; Reich, W. to be submitted for publication. (4) (a) Schrock, R. R. ACC.Chem. Res. 1986, 19, 342. (b) Dotz, K. H.; Fischer, H.; Hofmann, P.; Kreissl, F. R.; Schubert, U.; Weiss, K . Transition Metal Carbene Complexes; Verlag Chemie: Weinheim, Germany, 1983. (5) (a)Fried, A,; Malisch, W.; Schmeusser, M.; Weis, U . Phosphorus, Sulfur Silicon Relat. Elem. 1992, 65, 7 5 . (b) Malisch, W.; Markl, M.; Amann, S.; Hirth, U.;Schmeusser, M. Phosphorus, Sulfur Silicon Relat. Elem. 1990, 49/50, 441. (c) Hirth, U.-A.;Malisch, W.; m b , H.; Bright, T.A. J. Organomet. Chem. 1992, 439, C20. (d) Pfister, H.; Malisch, W. J. Organomet. Chem. 1992, 439, C11. (e) Sporl, A,; Hindahl, K.; Fried, A.; Pfister, H.; Malisch, W. In Selective Reactions ofMetal-Activated Molecules; Werner, H., Griesbeck,A. G., Adam, W., Bringmann, G., Kiefer, W., Eds.; Vieweg: Braunschweig, Germany, 1992; p 191. (0 Fried, A.; Hahner, C.; Malisch, W. In ref 5e, p 195. +
plexes, we have investigated the decarbonylation of the functionalized species Cp(CO)sW-P(X)-t-Bu (la,X = C1; lb, X = H) and observed controlled, stereospecific formation of a cyclized phosphinidenemetallophosphorane, containing a hydrogen- or chlorine-substituted phosphorus, useful for further derivatization. The metallophosphines la,b are generated by metalation of t-BuPClz with Na[W(CO)&pI in benzene (la) or via deprotonation of the cationic complex [Cp(COh(t-BuHzP)W]BF4with triethylamine in toluene (lb), respectively. Both compounds analogously convert in solution (la, 24 h, benzene, room temperature; lb, 3.5 h, toluene, 80 “C) to the three-membered diphosphametallacycles 2a,b and the chlorohydrido tungsten complex 3a,b (Scheme 1). 2a,b can easily be separated by extraction with pentane (2a)or column chromatography (Zbh6 The generation of 2a,b is explained via decarbonylation of la,b, leading to the M-P intermediates Cp(C0)2W=P(X)-t-Bu (X = C1, H)and simultaneous decomposition to 3a,b, with elimination of “tert-butylphosphinidene”, which immediately adds to the M=P bond. Evidence for this reaction mechanism is provided by the easy transfer of the “MeP” moiety to the stable phosphenium complexes Cp(CO)zW=PRz (R = t-Bu, o-Tol) using (MeP)5.7 An additional access to 2b is offered by treatment of 2a with LiAlH4 in benzene.6 According to NMR spectroscopy PH, 13C, 31P)6the compounds 2a,b exist only as one diastereomer, indicating stereocontrolled coupling of the phosphenium ligand and the “tert-butylphosphinidene” unit. The stereochemistry of 2a,b has been proven by X-ray analysis,8 illustrated in Figures 1 and 2. It reveals that the tertbutyl groups, in agreement with the steric requirement, are located on different sides of the ring plane. The H or C1 atom at the phosphorane phosphorus P1 is in a position anti to the Cp ligand, while the lone pair a t the phosphinidene phosphorus P2 in that respect adopts a syn ~rientation.~ In addition the X-ray study provides support for our description of 2a,b as cyclic phosphinidenemetallophosphoranes, in which the metal acts as a coordination center for the phosphinidene phosphorus P2 as well as a a-bonded ligand to P1.l0 The diverse kinds of bonding of the phosphinidene-phosphorane unit t o the metal are documented by the significantly different W-P1 and W-P2 distances in 2a,b. While
Q276-7333I95/2314-4446$Q9.QQ/Q 0 1995 American Chemical Society
Organometallics, Vol. 14, No. 10, 1995 4447
Communications Scheme 1
4p
&Q
t-eu
+K
CH4I
Figure 1. Drawing of 2a. Selected bond lengths (A): W1P1= 2.355(2),Wl-P2 = 2.572(2),P1-P2 = 2.101(3), C11P1 = 2.059(3). Selected bond angles (deg): Pl-Wl-P2 = 50.25(7), W1-P1-P2 = 70.25(8), W1-P2-H = 59.50(8). Hydrogen atoms are omitted for clarity. c7
c3
5
Figure 2. Drawing of 2b. Selected bond lengths (A): W1P1 = 2.411(3), Wl-P2 = 2.576(3),P1-P2 = 2.095(4), P1H1 = 1.27(4). Selected bond angles (deg): Pl-Wl-P2 = 49.54(9),Wl-Pl-P2 = 69.33(11),Wl-P2-P1= 61.13(10). Hydrogen atoms (except for H1) are omitted for clarity. the metal-phosphorane phosphorus distances W-P1 of 2.355(2) A (2a)/2.411(3) A (2b) lie between those of W-P double and single bonds,l' the values of W-P2
bonds (2.572(2) (2a)/2.576(3) A (2b)) are comparable to those of metal-phosphorus single bonds in the phosphido complexes Cp(C0)2(L)W--PPhz (d(W-P) = 2.615-
(3) A (L= CO), 2.545(2) A (L= PMe3)).12 A considerable double-bond character of the P-P unit is established (6)Experimental details are given in the supporting information. Analvtical and sDectroscoDical data are as follows. tertButvlchloro[ t i ~ ~ n y l ( q ~ ~ c l o p e n ~ d i e n y l ~ t(la) u n mp gste~ 51 "C dec; lH NMR (60MHz, CaHa) 6 4.80 (d, 3 J ~ w = c~ 1.9 Hz, 5 H, C5H5),1.39 ppm (d, 3JpcCH = 13.3 Hz, 9 H, (Hac)&); 31P{1H}NMR (36.2MHz, CDs) 6 197.1ppm (s, lJwp = 29.8Hz); IR (pentanej v(C0) 2012 (vs), 1952 (s), 1927 cm-l (vs); MS (based on 35C1 and '@W) mle 456 (M+). Anal. Calcd for C12H14C103PW (456.53):C, 31.57;H, 3.09; C1 7.77. Found C, 30.70; H, 3.10; C1, 8.00. [Tricarbonyl(qScyclopentadienyl)tungetenioltert-butylphosphine (lb): 'H NMR (200.1MHz, CsDe) 6 4.59(d, 3Jpwc~ = 1.8 Hz, 5 H, C5H5), 3.95(d, 'JPH = 212.2Hz, 1 H, PH), 1.43ppm (d, 3JPCCH = 12.5Hz, 9 H, (H&)3C); 31P{1H}NMR (36.2MHz, C&) 6 -71.6 ppm (9, 'Jwp = 52.8 Hz); IR (pentane) v(C0) 2001 (s), 1935 (s), 1920 cm-l (vs), v(PH) 2259 cm-Yw).
Dicarbonyl(q~-cyclopentadienyl)[qa-(tert-butylphosphinidene)tert-butylchlorophosphorane-PJYtungsten(II) (2a): mp 93 "C; 'H NMR (here and in the following compounds the tetravalent phosphorus is assigned as Pa and the trivalent phosphorus as Pb)(60 MHz, C & 3 )6 4.84(dd, 3 J p b w c ~= 1.4Hz, 3Jp.wc~ = 0.6Hz, 5H, H5C5), 1.44 (dd, 3 J p b=~ 13.9 ~ ~ Hz, 4JppbCCH= 1.3 Hz, 9H, H3CCPb),1.26 ppm (dd, 3Jp.cc~ = 21.2 Hz, 4Jpbpcc~= 0.3Hz, H3CCPa); 3'P{'H} NMR (36.2 MHz, &De) 6 118.58(d, 'Jppb = 549.11 Hz, Pa), -196.86 ppm (d, 'Jpbp. = 549.11 Hz, Pb);13C{'H} NMR (22.6MHz, C&j) 6 228.3 (dd, 2Jpbwc = 29.6 Hz, 2Jp.w~= 2.3 Hz, COB), 29.8 (9, br, Cob), 89.0(d, 2 J p .=~ ~ 2.9 Hz, C5H5), 40.8 (d, lJp.c = 22.9 Hz, (H3C)3CPa),32.3 (dd, 'Jpbc = 59.4Hz,'Jpphc = 6.8Hz, (H3C)3CPb),32.4 (dd, 2 J ~=c18.4Hz, 3Jp.~c = 5.2 Hz, (H&)&Pb), 27.3ppm (dd, 2 J p .=~5.5 ~ Hz, 3 J ~ b=p3.7 ~~ Hz, (H3C)3CPa);IR (pentane) v(C0) 1959 (vs), 1883 cm-Vs); MS (based on 35C1 and 1MW) mle 517 (M+). Anal. Calcd for ClsH23C102PzW (516.60):C, 34.88;H, 4.49;C1, 6.86. Found: C, 35.01;H, 4.67;C1, 7.14. Dicarbonyl(g~-cyclopentadienyl)[q2-(~e~-butylphoaphinidene)-tert-butylphosphorane-P,P'ltungsten~II) (2b):mp 110 "C; 'H NMR (200.1MHz, C&) 6 5.24(dd, 'JFH = 415.0Hz, 2Jpbpq = 3.4 Hz, lH, P'H), 4.85 (d, 'Jpbwc~= 1.3Hz, 5H, H5C5), 1.22(dd, 3Jpbcc~= 13.8 Hz, 4Jppbcc~= 1.8 Hz, 9H, (H3C)3CPb),0.93 (d, 3Jp.cc~= 19.2 Hz, 9H, (H&)&Pa); 31P{1H}NMR (36.2MHz, CsD6) 6 -26.1 ('Jppb = 489.8 Hz, P*), -191.6 ppm ( l J p b p . = 489.8 Hz, Pb);l3C(lH}NMR (100.6 MHz, C&s) 6 231.86 (dd, 2Jpbwc = 23.8 Hz, 2Jp.wc= 2.9 Hz, Coal, ~ C5H5), 31.81 (dd, 'Jpc = 224.55(6, br, Cob),87.96(d, 2 J p =~2.~9 Hz, 16.8Hz, 2Jpbw:= 4.9Hz, (CH3)3cPa),29.25 (dd, 2Jp.cc= 4.7Hz, 3Jpbp.cc = 1.8 Hz, (CH3)3CPa),27.52 (dd, 'Jpbc = 50.3 Hz, 2Jppbc = 4.9 Hz, (CH3)3CPb),27.47 ppm (d, 2Jpk~ = 29.8 Hz, (CH3)3CPb);IR (pentane) v(PH) 2319 (w), v(C0) 1942 (s), 1870 (8)cm-l; MS (based on law) mle 482 (M+),425 (M+ - C4H9),397 (M+ - C4H9 and CO), 339 (M+ - 2 C4H9 - CO - H), 311 (C5HsWP2+), 57 (C4Hg+). Anal. Calcd for C15H2402P2W (482.16):C, 37.37;H, 5.02. Found C, 36.72;H, 4.98. Dicarbonyl(qs-cyclopentadienyl~[qz-~tert-butylphoaphinidene~methyl-tert-butylphosphorane-P97tungsten(II) (4a):mp 133 "C; 'H NMR (400.1MHz, C&) 6 4.90(s,5H, H5C5) 1.81 (d, 2 J p .=~11.0 ~ Hz, 3H, H3CPa),1.23(d, 3JpbCCH= 13.4 Hz, 9H, (H3C)3CPb),0.86ppm (d, 3Jp.cc~ = 16.9Hz, 9H, (H3C)3CPB); 31P{1H}NMR (162.0MHz, C6De) 6 -5.07 (d, lJp.pb = 534.2 Hz, l J w = 169.5 Hz, Pa), -180.8 ppm (d, 'Jpbp = 534.2 Hz, Pb); 13C{'H} NMR (100.6MHz, C&) 6 234.00 (d, 'Jpbwc = 24.8 Hz, COB), 224.87 (5, Cob),89.66 (d, 2 J ~=c3.0 Hz, C5H5), 32.87(dd, 2Jpbcc = 18.2 Hz, 3Jp.pbcc = 4.8 Hz, (CH3)3CPb),30.63(dd, lJpbc = 58.1 Hz, 'Jppbc = 6.8 Hz, (CH3)3CPb),30.18 (dd, 'Jpac = 26.1 Hz, 2Jpbp.c= 2.0Hz, (CH3)3CPa),27.99(dd, 'Jp.cc = 4.0Hz, 3 J p b w c = 3.9 Hz, (CH3)3CPa), 12.56 ppm (dd, 'Jpq = 27.7 Hz, 2Jpbpy = 3.6 Hz, CH3Pa);IR (pentane) v(C0) 1933 (s), 1860 (8) cm-'. Anal. Calcd for C16H2eOzPzW (496.18):mle C, 38.73;H, 5.28. Found: C, 38.67;H, 5.52. Dicarbonyl(qs-cyclopentadienyl)[qa-te~butylphoaphinidene)allyl-tert-butylphosphorane-P,P'ltungsten(II)(4b):mp 94 "C; 1H NMR (400.1MHz, [D&oluene, 203 K)6 6.40(m, lH, HaC=CH2), 5.14(d, 3 J ~ a c c ~=b 9.7 Hz, 1H, HbHcC=CHa), 5.04 (d, 3JH.ccHc = 15.2 Hz, lH, HbH'C-CHa), 4.86 (5, 5H, H5C51, 3.61 (dd, 2 J = 14.6 ~ ~Hz, ~ 3 J ~ c c=~8.3 * Hz, lH, H H2C); 3.26 (dd, 2 J = 14.4 ~ HZ, ~ 3J~cc~a ~ = 4.8Hz, lH, HzC), 1.56(d, 3JpbCCH= 10.3 Hz, 9H, (H3C)3CPb),1.20ppm (d, 3Jp.CCH= 16.7Hz, 9H, (H3C)3CPa);31P{1H}NMR (162.0MHz, C6D6) 6 0.74(d, 'Jpbp. = 537.1 Hz, lJwpp = 170.1 Hz, Pa), -169.84 ppm (d, 'Jp.pb = 537.1Hz, Pb); '3C{'H} NMR (100.6MHz, C&) 6 234.56 (d, 2 J ~ =c 26.5 Hz, COB), 224.67 (s, Cob), 135.40 (d, 2Jpacc = 9.0 Hz, CHa-CHbHc). 118.18 (d. 3 J m ~ p=~12.0 Hz. CHa-CHbH'). 88.66 (d. 2Jpbwc = 3.2 Hz,C5H5) 37.7%-?idd,lJpac = 78.2 Hz, 'Jpbpc = 3.6 Hzj CHd, 32.85(dd, 2Jpkc= 18.8Hz, 3 J p a p b ~=~ 4.7Hz, (CH3)3CPb),32.28 (dd,1Jp.c = 27.9 Hz, 2 J e w = 2.4Hz, (CH&CPa), 31.45 (dd,'Jpbc = 60.9Hz, 2Jppv = 7.3Hz, (CH3)3CPb),29.40ppm (d, 2 J = 3.7 ~ Hz, ~ ~ (CH3)3CPB);IR (petroleum ether, 40-60 "C) v(C0) 1933 (vs), 1859 (s) cm-l. Anal. Calcd for C ~ ~ H ~ ~ O(522.22): Z P ~ W C, 41.40;H, 5.40. Found: C, 40.98H, 5.03. Dicarbonyl(q~-cyclopentadienyl[q2-l,2di-tert-butyl-1,2-dimethyldiphosphineltungsten(II) iodide (5): mp 171 "C; 1H NMR (CD3N02) 6 5.83 (t, 3JPWCH= 0.3Hz, 5H, HsCs), 2.29 (vt, N = 1.9 Hz, 6H,HsCP), 1.42 ppm (vt, N = 19.8 Hz, 18H, (H&C); 31P{1H} NMR (CD,N02,245 K, AB spectrum) 8~ -84.2 ('JAB = 384.1 Hz, 'Jwp = 128.0Hz), 6 g -97.2 ppm WAB = 384.1Hz, lJwp = 153.3Hz); IR (acetonitrile) v(C0) 1984 (vs), 1904 (s)err-'. Anal. Calcd for C ~ ~ H ~ S I O(638.12): ~ P ~ W C, 32.00;H, 4.58;I, 19.89. Found: C, 32.21;H, 4.71;I, 19.64.
4448 Organometallics, Vol. 14, No. 10, 1995 by the Pl-P2 distances (2.101(3)A (2a)/2.095(4) A (2b)), similar t o what has been found for comparable systems prepared by different routes.13 Further evidence for this fact is given by the high value of the coupling constant l J p p = 549.3 Hz (2aY489.8Hz (2b). Due t o its PH functionality, 2b opens up the possibility of phosphorus metallation. The spontaneous reaction of 2b with n-BuLi already occurs at -78 "C in THF, yielding the lithiated species Li[Cp(CO)ZW-P(tBu)-P(t-Bu)l,14 which reacts "in situ" with methyl or allyl iodide to give the methyl- or allyl-substituted phosphinidenemetallophosphoranes 4a,b (Scheme 2), purified by column chromatography. Alkylation proceeds presumably with retention of configuration at the phosphorane phosphorus, evident by comparison of 31P NMR parameters of 4a,b with those of 2b. In accordance with the trivalency of the phosphinidene phosphorus, 4a is quaternized with methyl iodide in toluene at room temperature, yielding the pale yellow (7)Malisch, W.; Hindahl, K.;Schemm, R. Chem. Ber. 1992, 125, 2027. (8)2a: orange crystals of 2a, suitable for X-ray analysis, were obtained by low-temperature crystallization from pentane at -40 "C; C ~ ~ H ~ ~ C ~M O~ Z W , Crystallographic data for 2a: monoclinic, = P516.60. P21/n, Z = 4, a = 11.888(3)A, b = 11.103(3)A,c = 14.798(4)A, j3 = 94.32(2Y, V = 1947.6(16)A3, ecslc= 1.76 g ~ m - Enraf-Nonius ~, CAD4 diffractometer, Mo Ka radiation (1 = 0.710 93 A);3419 independent reflections with 3.0"
