1551
Organometallics 1991, 10, 1551-1560
Reactions of Compounds Containing Ni-Ni, Ni-Mo, and Ni-W Bonds with Allene and 1,l-Dimethylallene. X-ray Diffraction Studies of the m-Allylic Complexes N ~ M O ( C ~ ) ~ { ~ - ~ ~ , ~ ~ - C ~ (q5-C,H,Me) H , ~ ) ( ~ ~ - Cand ,H,) NiMo(p-CO) (CO){p-q1,q3-C(Me)-C( Me)-CH,i(q5-C,H,) (q5C,H,Me) (Ni-Mo) Michael J. Chetcuti,
*9t
Phillip E. Fanwick,’ Steven R. McDonald,+.*and Nigam N. RathtgI1
Department of Chemistty and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, and Department of Chemistry, Purdue University, West Lafayette, Indiana 47907 Received September 25, 1990
The reactions of the dinickel species [Ni(p-Co)(qS-C6H5)]z (Ni-Ni) and of the mixed-metal complexes
(q5-CsH5)(CO)Ni-M(CO)3(q6-CsH,Me) [la, M = Mo; lb, M = W] with propa-1,Zdiene (allene) and 3-
methyl-1,2-butadiene (1,l-dimethylallene)are described. When [Ni(p-CO)(q6-CsH6)]z (Ni-Ni) is treated with allene, the nickel-nickel bond is ruptured and two allene units couple forming the 2,2’-bis(allyl) species (q6-C5H6)Ni(p-q3,q3-CsHe)Ni(q5-C5H5) (2). No reaction ensues when the Niz complex is treated 1,l-dimethylallene. la and l b react with allene, but the only heterobimetallic product characterized was (q5-C6Hs)Ni(p-q3,q3-CgH12}Mo(~~)z(q6-C6H4Me) (31, whose structure was determined by an X-ray diffraction ligand that tethers the two metal study. Complex 3 contains no metal-metal bond, and the p-q3,q3-CsHl2 centers together, derived from the trimerization of three allene units, is q3-coordinatedin a T-allyl fashion to each metal. Both 2 and 3 exhibit interesting CIMS: when isobutane is used as the ionization gas, a butyl cation adds on to the parent molecule of both species, forming (M + 57)+ ions for both species. -C H ) (la’) to form 1,l-Dimethylallenereacts with complexes la, lb, and (sS-CsHM~)(CO)N~-MO(CO)~(~ (CH,))M(CO),(q -C6H4R)(Ni-M) the 2-nickel-substituted allylic complexes (qS-CSHs)Ni(p-ql,~-C(CMez) (Ni-Mo) (4a’), [4a, M = Mo; 4b, M = W] and (q6-C5H4Me)Nilp-q1,q3-C(CMez)(CHz)JMo(CO)z(q6-CdH5) respectively. On silica gel, isomerization to the l-nickel-substituted allyl species ( q -C6H5)Ni(p-q1,q3-C(Me)-C(Me)-CH2)(pz-CO)M(CO)(q5-C5H4Me) (Ni-M) [5a, M = Mo; 5b, M = W] and (q5-C5H4Me)Ni(pq1,&C (Me)-C (Me)-CHz)(p2-CO) Mo(CO)(q6-CsH5)(Ni-M) (5a’), respectively, takes place. Complex 4b reductively eliminates a nickel atom in a side reaction to form an isomeric mixture of 2-substituted 1,3and 1,4-cyclopentadienyl-1,l-dimethylallyl species W (C0)z(q3-(CH2-C(CsHs)-CMez)}(q5-C5H4Me) (6b). Related allene derived isomers W(CO)2(q3-(CH2-C(C&&-CHJ(q5-C&4Me) (6)were lsolated from the reaction of allene with lb. Labeling studies using 1,l-dimethylallene-3-dlor acetic acid-dl demonstrated that an effective 1,l-proton shift and not a 1,Zmethyl group migration was operative in the isomerization of 4a-dl to 5a-dl. In contrast to the reactivity exhibited toward cumulated dienes, neither la nor l b reacted with isoprene.
Introduction A full understanding of the role metals play in promoting carbon-carbon bond formation and hydrocarbon skeletal rearrangements remains elusive despite advances made in di- and polynuclear organometallic chemistry. While synthetically useful reactions have been developed from the interactions of dimetallic systems with hydrocarbons,l the outcome of the reaction of a hydrocarbon with a particular dimetallic complex is often unpredictable, especially when dissimilar metals are involved: novel compounds often result or the “expected” species may have a transient existence en route to a new rearranged final product. The chemistry of the mixed-metal complexes (q5C5H6)(CO)Ni-M(C0)3(q6-C6H4Me) [la, M = Mo; lb, M = W] with unsaturated hydrocarbons has been the focus of recent research in our group.z4 Significant differences are observed between the reactivity of the group 6-group 10 complexes la and l b and the chemistry exhibited toward the same reagents by either the dimolybdenum/dior the dinickel tungsten systems [M(C0)z,3(q6-C6H5)]z University of Notre Dame.
* Purdue University.
‘Current address: Union Carbide Corp., South Charleston, WV 25303. Current address: Department of Chemistry, Washington University, St. Louis, MO 63120.
0276-7333/91/2310-1551$02.50/0
la, M = Mo; R = H;R’= Me la’, M = Mo; R = Me; R = H lb, M = W; R = H;R = Me
compound [Ni(p-CO)(v5-C5Hs)] (Ni-Ni).4*5 Reactions of these heterodinuclear species also diverge from those displayed by the isoelectronic diiron species Fe2(CO)4(95-C5Hs)z. To date the bulk of our published work has focused on reactions of these and related species with alkynes. Allenes customarily act p-q2,q2-ligandstoward (1) (a) Bilhgton, D. C.; P a w n , P. L. Organometallics 1982,1,1560. (b) Padmanabhan, S.; Nicholas, K. M. Tetrahedron Lett. 1983,24,2239. (c) Exon, C.; Magnus, P. J. Am. Chem. SOC.1983,105,2477. (d) Caeey, C. P.; Fagan,P. J. J. Am. Chem. SOC.1982,104,4950. (e) Paueon, P. L. In Organometallics in Organic Synthesis; de Meijere, A., tom Dieck, H., Eds.; Springer: Heidelberg, Germany, 1987; p 233. (fj S b - F i n k , G.; Neumann, F. In The Chemistry of the Metal Carbon Bond; Hartley, F. R., Ed.;John Wiley and Sons: London, 1989; Vol. 5. (2) Azar, M. C.; Chetcuti, M. J.; Eigenbrot, C.; Green, K. A. J. Am. Chem. SOC.1985,107,7209. (3) Chetcuti, M. J.; Eigenbrot, C.; Green, K. A. Organometallics 1987, 6, 2298. (4) Chetcuti, M. J.; Green, K. A. Organometallics 1988, 7, 2450. ( 5 ) Chetcuti, M. J.; Fanwick, P. E.; Gordon, J. C.; Green, K. A.; Morgenstern, D. Organometallics 1989,8, 1790.
0 1991 American Chemical Society
1552 Organometallics, Vol. 10, No. 5, 1991 C&Meb 4.85, 4.78, 4.68, 4.65 5.02: 4.95, 4.84 4.88, 4.83, 4.74, 4.67 4.66: 4.60, 4.51 4.98, 4.84, 4.75‘ 4.71,d 4.69, 4.58
ca6
4a 4a‘ 4b 5a Sa’ 5b a
5.14 4.94 5.13 5.03 4.82 5.02
Table I. IH NMR Data CHH (eyn) 4.22 4.29 4.31 2.94 (d) (JHH= 1.52) 3.02 (d) (JHH = 1.37) 2.78
Spectra recorded in chloroform-d,. bABCD multiplets. ‘2 H.
co 4a 4aJd 4be Sad 5a’ 5b a
Chetcuti et al.
254.0, 238.7 255.3, 237.3 240.2, 227.1 (Jwc 262.9 ( p ) , 229.8 263.4 ()I, 229.3 251.3 ( p ) , 217.0
Me 2.35, 1.83 (Jm 0.44) 2.29, 1.19 2.44, 1.15 2.15: 1.83 2.17,” 1.83 2.24: 2.00 ( J m = 3.35)
CsH&e 2.04 1.86 2.18 2.01 1.85 2.13
Ni-C(Me).
c H 2
54.0 53.2 46.6 51.1 50.8 41.7 (Jwc = 9)
Me CsH,Me 32.9, 23.7 13.4 32.8, 23.6 12.3 33.9, 24.6 13.5 29.9, 20.4 13.0 29.7, 20.5 12.5 29.5, 20.2 13.0
Assigned from ‘H-coupled spectrum. e Acetone-de ’Broad. gNi-C(Me).
dimetal compounds, mimicking bridging alkynes in palkyne complexes; an exploration of the reactions of allenes with la and l b was therefore of interest. Reactions of the dimolybdenum species [ M o ( C O ) ~ ( ~ ~ C6H4R)I2(R = H, Me; M m M o ) with allenes have been probed by Chisholm6 and Curtis:’ bridging q2,q2-allene compounds resulted with allene or monosubstituted allenes, but 1,l-dimethylallene was unreactive toward these metal complexes. Nickel(0) complexes display an interesting reactivity toward allenes,8 but to our knowledge, reactions of the dinickel complex [Ni(p-CO)(q5-C5H5)]2 with allene or 1,l-dimethylallene are not documented. These are reported here, followed by a discussion of the reactions of la and lb with these dienes. Some aspects of this work have been comm~nicated.~
Results and Discussion (a) Reaction of Allene and 1,l-Dimethylallene with [Ni(p-CO)(+C6H5)]2(Ni-Ni). Allene (l,a-propadiene, CH2=C=CH2)reacts slowly with red hexane solutions of this nickel species to afford a dark red compound (2). The ‘H NMR spectrum of 2 (Table I) reveals a singlet at 6 5.29 ppm that may be assigned to a q5-C5H5group; two other singlets are observed at 3.01 and 1.62 ppm, at ranges characteristic of syn and anti protons of a-allylic species. Complex 2 exhibits no v(C0) absorptions in its IR spectrum. These spectroscopic results and the E1 (electron ionization) MS are in accord with 2 being the 2,2’-bis(a-allyl) complex Ni2(p-q8,q3-C6H8) (q5-C6H5)z. [The chemical ion-
L
ization mass spectrum (CIMS) of 2 is discussed later.] Two allene unita are reduced to a “tetramethyleneethane”ligand with the concurrent formal oxidation of a pair of nickel H.;Rankel, L. A.; Bailey, W. I., Jr.; Cotton, F.
A.; Murillo, C. A. J. Am. Chem. Soc. 1977,99,1261. (b) Bailey, W. I., Jr.; Chirholm, M. H.;Cotton, F. A.; Murillo, C. A.; Rankel, L. A. J. Am. Chem. Soc. 1978,100,802. (7) Meyer, A.; McCabe, D. J.; Curtis, M. D. Organometallics 1987,6, 1491. (8) Pasto, D. J.; Huang, N.
CHH (anti) 2.81 2.95 4.82) 2.89 (J2.76 (m) 2.79 (m) 2.77
Table 11. ‘42NMR Data (6, ppm; J, Hz)” C-CHQ CJZK CsH,Me C(Me) 171.6 93.9 107.2,b 94.0, 93.0, 91.7, 90.9 119.W 172.4 91.6 106.6,b96.0, 94.9, 92.7, 90.2 119.5’ 173) 173.7 (Jwc = 7) 94.2 105.9,b93.4, 91.8, 89.8, 89.6 110.8‘ 145.68 93.1 107.7,b94.4, 92.6, 92.0, 91.8 101.6 146.38 92.4 105.6,b94.8, 94.1, 91.9, 90.8 101.2 131.58 93.6 106.6,*93.1, 92.6, 91.1, 89.8 99.8
Spectra acquired in choroform-d, C(Me). CMe,.
(6) (a) Chisholm, M.
(6, ppm; J, Hz)”
2.Organometallics 1986,4, 1386. (9) Chetcuti, M.J.; McDonald, 5.R.; Rath, N. P. Organometallics 1989,8, 2077.
comDlex 3
Table 111. LR v(C0)Data (cm-’) hexanes Nujol 1961 (s), 1891 ( 8 ) 1951 (m), 1940 (a), 1888 (w), 1861 ( 8 )
4b 5a 5a’ 5b 6a 6b
1928 (w),1809 (s) 1929 (s), 1803 ( 8 ) 1911 (s), 1811 (a) 1948 (a), 1784 (a) 1949 (a), 1782 ( 8 ) 1944 (s), 1778 ( 8 ) 1948 (s), 1878 (a) 1946 (s), 1872 (a)
6b
1954 (a), 1881 ( 8 )
4a 4a’
1924 (a), 1790 (a) 1934 (a), 1787 (a) 1913 (a), 1794 ( 8 ) 1936 (a), 1757 (a) 1942 (a), 1768 (a) 1939 (4, 1755 (a) 1943 (a), 1918 (m), 1868 (a), 1840 (m)
CHpClzsolution. * KBr pellet.
atoms from Ni(1) to Ni(I1). A new C-C bond replaces the ruptured Ni-Ni bond present in [NiG-CO)(q6-C5H5)I2. The reaction is shown in eq 1. [Ni(p-CO)(q5-C,H5)1,+ 2CH2=C=CH2 Ni2(~-q3,q3-C6Hs)(q5-C5H5)2 + 2C0 (1) The identity of 2 was confirmed by comparing its spectroscopic data with those reported for the independently prepared complex Ni2(~-q3,q3-C6H8)(t16-CgH~)2,10 whose structure has been determined by X-ray diffraction.” The manganese12 and iron13 complexes Mn2(CO),(p-q3,q3-C6H8)(no Mn-Mn bond) and Fe2(CO)6(p73,q3-C6H8)(Fe-Fe), which contain similar ligands, result when Mn2(C0)10and Fe2(CO)9,respectively, are photolyzed with allene. When [Ni(p-CO)(q5-C5H6)]2was reacted with 1,l-dimethylallene (Me2C=C==CH2,3-methyl-buta-1,2-diene), no complexes containing this ligand could be isolated. The diene was consumed slowly, but nickelocene and the l4 paramagnetic trinickel cluster [Ni3(pa-C0)2(q5-C6HS)31 were the only new organonickel species characterized. (b) Reactions of Allene with la and lb. (i) Reaction Description. Molecules of stoichiometry NiM(CO)?(pq2,q2-CH2=C=CH2)(q5-C5H5)(q5-C5H4Me) were not iso-
-
(10) Keim, W. Angew. Chem., Znt. Ed. Engl. 1968,11,-879. 2 is obtained from the reaction of a mononuclear palladium chloroallyl complex with bis(l,5-~yclooctadiene)nickel,followed by treatment with C H6-. The mixed nickel-palladium species formed slowly affords 2 and the analogous dipalladium species. (11) Smith, A. E. Inorg. Chem. 1972, 11, 165. (12) Kreiter, C. G.; Leyendecker, M.; Sheldrick, W. S. J. Orgonomet. Chem. 1986,302, 35. A 1971,154. (13) (a)Otsuka, S.; Nakamura, A.; Tani,K. J. Chem. SOC. (b) Sadeh, S.; Gaoni, Y. J. Organomet. Chem. 1976,93, C31. (14) Fischer, E. 0.; Palm,C. Chem. Ber. 1958,91, 1725.
Reactions of Ni-Ni, Ni-Mo, and Ni- W Compounds Table IV. Crystal and Data Collection Parameters for 3 and 5a 3 5a formula CBHuMoNi02 ClaH&oNiO2 fw 475.09 423.10 space group P 2 1 / ~(NO.14) P21/n (NO. 14) 9.104 (3) 14.104 (1) a, A 15.840 (16) 15.444 (2) b, A 9.952 (1) 11.559 (4) 94.20 (3) 110.558 (8) 1662.3 (9) 2029.6 (7) 4 4 1.690 d*, g cm-a 1.555 0.49 X 0.44 X 0.15 0.35 X 0.35 X 0.45 cryst dimens, mm 25 20 temp, "C 0.71073 0.710 73 X(Mo Ka),A monochromator graphite graphite g(Mo Ka),cm-l 15.47 18.79 not applied abs corr empirical Enraf-Nonius diffractometer Enraf-Nonius CAD-4 CAD-4 w-28 8-28 scan method h, k, 1 limits 0 to 15, -16 to 0, -11 to 13,O to 23, -10 to 10 1to 17 28 range, deg 4.00-45.00 3.20-64.0 scan width, deg 0.79 + 0.35 tan 8 0.80 + 0.35 tan 0 programs used Enraf Nonius SHELXS
SDP no. of data collcd, 2778, 2778 no. of unique data no. of data with 2238 I > 3.0a(0 no. of variables 235 R 0.035 0.045 R" goodness of fit 1.57
Organometallics, Vol. 10, No. 5, 1991 1553 Table V. Fractional Atomic Coordinates for 3 atom X Y z Mo 0.29976 (3) 0.58224 (2) 0.10968 (4) 0.12127 (4) 0.33543 (4) 0.47221 (6) 0.1214 (3) 0.4525 (3) -0.0131 (3) 0.4077 (3) 0.4103 (3) 0.0971 (5) 0.1889 (4) 0.5018 (3) 0.0366 (5) 0.3691 (3) 0.4755 (3) 0.1067 (5) 0.4023 (4) 0.5822 (3) 0.3481 (5) 0.5477 (3) 0.3081 (3) 0.3380 (4) 0.6003 (3) 0.2233 (4) 0.2790 (5) 0.3704 (4) 0.2047 (4) 0.6718 (5) 0.3691 (3) 0.2589 (3) 0.5769 (5) 0.2891 (3) 0.2585 (4) 0.5095 (6) 0.4561 (3) 0.2983 (3) 0.3832 (4) 0.4496 (3) 0.2987 (3) 0.5356 (4) 0.5098 (4) 0.3383 (4) 0.6339 (5) 0.7044 (3) 0.3946 (4) 0.0784 (5) 0.6479 (3) 0.3746 (3) -0.0383 (5) -0.1111 (5) 0.6434 (3) 0.2710 (4) 0.6947 (3) -0.0405 (5) 0.2239 (4) 0.7336 (3) 0.2982 (4) 0.0765 (5) 0.7338 (5) 0.1766 (8) 0.4966 (5) 0.4088 (4) -0.0066 (5) 0.3445 (9) 0.3590 (5) 0.0282 (4) 0.2552 (6) 0.2719 (5) 0.0239 (4) 0.2955 (6) 0.2692 (4) -0.0163 (4) 0.4006 (6) -0,0319 (4) 0.4353 (6) 0.3507 (5)
5509, 5509 3426 279 0.039 0.043 1.32
lated from these reactions. Any heterobimetallic monoallene species resisted characterization and ultimately decomposed yielding intractable products and/or oils. Though the bulk of the allene appeared to oligomerize,16 a tan species (3) was harvested in moderate yield (18%) by reacting la with excess allene under carefully controlled conditions. The corresponding nickel-tungsten complex was not isolated when lb was treated with allene, but a yellow oil containing a tungsten species 6 (discussed later) was isolated from this reaction. The 'H, '9c NMR (Tables I and 111, and IR data (Table 111) suggest that 3 can be formulated as NiMo(CO)2(CSH4~s(t16-CpH4Me)(s6-C6H6). Four singlets spanning the chemical shift range of 6 2.93-1.76 ppm are observed in its 'H NMR spectrum. In addition, both AB-type multiplets (centered a t 5.35 and 5.29 ppm) and a singlet (at 1.16 ppm) accounting for two hydrogen atoms are seen. Signals for $-C6H6 and $-CJ-14Me groups were also noted and the AA'BB' spin system exhibited by the aromatic q6-C6H4Meprotons implies that an effective mirror plane of symmetry is present, at least on the 'HNMR time scale. EIMS data corroborate the proposed empirical formula. [CIMS data for 3 (cf. 2) are unusual and will be discussed shortly.] A molecular structure of 3 consistent with these spectroscopic data can be proposed.
(15) Thie allene oligomerization resembles the polymerization of eth#,q*-C*H, complexes are isolated yne observed with la or lb.' Brionly under closely monitored conditions.
Table VI. Mo-C(1) Mo-C(l1) Mo-C(l3) Mo-C(l02) Mo-C( 104) NiC(21) Ni-C(23) Ni-C(202) Ni-C (204) 0(1)-C(1) C(ll)-C(l2) C(12)-C(31) C(22)-C(23) C(31)-C(32) C(lOl)-C(lO6) C(Cp)-C(Cp) Ni-C(Cp)
Selected Bond Distances (A) for 3 1.929 (5) Mo-C(2) 1.922 (4) 2.305 (4) Mo-C(12) 2.297 (3) 2.314 (4) Mo-C(101) 2.396 (4) 2.324 (4) Mo-C(l03) 2.293 (4) 2.296 (4) Mo-C(105) 2.359 (4) 1.995 (4) NiC(22) 1.924 (4) 1.972 (5) Ni-C(201) 2.131 (6) 2.128 (5) Ni-C(203) 2.061 (5) 2.085 (5) Ni-C(205) 2.073 (5) 1.182 (5) 0(2)-C(2) 1.167 (5) 1.402 (6) C(12)-C(13) 1.393 (6) 1.504 (5) C(21)4(22) 1.408 (6) 1.405 (6) C(22)-C(32) 1.480 (5) 1.519 (5) C(32)-C(33) 1.322 (6) 1.498 (6) 1.397 (av) 1.381 (av) C(Cp')-C(Cp') 2.334 (av) 2.096 (av) Mo-C(Cp')
Table VII. Selected Bond Angles (deg) for 3 C(l)-Mo-C (2) 78.0 (2) C(l)-Mo-C(ll) 121.4 (2) 88.6 (2) C(l)-Mo-C(13) 80.2 (2) C(l)-Mo-C( 12) C(2)-Mo-C(11) 82.9 (2) C(2)-Mo-C(12) 88.1 (2) C(2)-Mo-C(13) 119.0 (2) C(ll)-Mo-C(12) 35.5 (1) C(ll)-M~C(13) 62.3 (2) C(12)-Mo-C(13) 35.2 (1) C(21)-Ni-C(22) 42.1 (2) C(21)-Ni-C(23) 73.4 (2) C(22)-Ni-C(23) 42.2 (2) Mo-C(l)-O(l) 177.5 (4) Mo-C(2)-0(2) 176.2 (4) Mo-C(11)-C(12) 72.0 (2) hloC(l2)-C(11) 72.6 (2) Mo-C(12)-C(13) 73.1 (2) Mo-C(12)-C(13) 122.4 (2) c(ll)-C(l2)-C(l3) 117.3 (4) C(ll)-C912)4(31) 121.3 (4) C(13)-C(12)-C(31) 121.3 (4) Mo-C(13)-C(12) 71.7 (2) Ni-C(21)-C(22) 66.3 (2) Ni-C(22)-C(21) 71.6 (2) Ni-C(22)-C(23) 70.7 (2) Ni-C(22)-C(32) 119.1 (3) C(21)-C(22)-C(23) 114.8 (4) C(21)-C(22)4(32) 121.5 (4) C(23)-C(22)-C(32) 123.0 (4) Ni-C(23)-C(22) 67.0 (2) C(12)-C(31)
