Organometallics 1995, 14, 5024-5029
5024
Articles Synthesis of @-Bis( amin0carbene))dimetalComplexes of Chromium and Iron by the Reaction of Tertiary Diamides with Cr(C0)52-or Fe(C0)d2-in the Presence of Chlorotrimethylsilane Miroslav Havrdnek,’ Michal Hugak,+and Dalimil DvoHk*vt Departments of Organic and Solid State Chemistry, Prague Institute of Chemical Technology, Technick6 5, 166 28 Prague 6, Czech Republic Received April 11, 1995@
Reaction of a n excess of Cr(CO)b2- with N,N,”,”-tetramethylisophthalamide (la)or the of pyridine-2,6-dicarboxylicacid (IC)in the presence of chlorotrimethylsilane readily gives (u-bis(aminocarbene))dichromiumcomplexes (CO)&rb-l,3(C(NM~Z))CGH~(C(NM~Z))IC~(CO)~ @a) or ( C O ) ~ C ~ ~ - ~ , ~ - ( C ( N M ~ Z ) ) ( C ~ H ~ N ) ( C ( N M ~ Z ) ) I C ~ C O ) ~ (2c),respectively. Under the same conditions, N,N,”,”-tetramethylphthalamide (lb), binaphthyl bis(amide) Id,and NJV,”,”-tetramethylsuccinamide (le)afford monocarbene complexes (C0)5Cr[C(NMe2)(2-(Me2NCO)C6H4)](3b),binaphthyl derivative 3c,and (CO)aCr[C(NMe2)((CH2)2CONMe2)1(3d)as the sole products. N,N,”,W-Tetramethylglutaramide (10and N,N,”,W-tetramethyladipamide (lg)form mixtures of both bis- and mono(carbene) complexes with the bis(carbene) complex strongly predominating. The reaction of Fe(C0)d2with diamide la or IC under similar conditions produces the (u-bis(amin0carbene))diiron complexes ( C ~ ) ~ F ~ ~ - ~ , ~ - ( C ( N M ~ Z ) ) C ~ H ~ ( C ( N (2b) M or ~ Z(CO>4Feb-2,6-(C(NMe2))))~F~(CO)~ ( C ~ H ~ N ) ( C ( N M ~ Z ) ) I F ~(2d), ( C Orespectively. )~ When a 1:l molar ratio of la and Cr(C0)52is used, the monocarbene complex (CO)~C~EC(NM~Z)(~-(M~ZNCO)C~H~)] (3a)is formed in moderate yield along with 2a. The monocarbene complex 3a can be converted to the mixed chromium-iron p-bidaminocarbene) complex (CO)~C~[CL-~,~-(C(NM~Z))C~H~(C(N~Z))IF~(C0)4 (4) on reaction with Fe(C0)2- and chlorotrimethylsilane. This complex was fully characterized by X-ray diffraction study.
N,N,”,”-tetramethylamide
The chemistry of Fischer carbene complexes, in particular that of chromium, is well established and has found many applications in organic synthesis.’ By contrast (p-bis(carbene)dimetal complexes of number of transition metals are rare2 and their synthetic potential remains to be e ~ p l o r e d .There ~ are several methods reported for the preparation of Fischer @-bis(carbene1)dimetal complexes of group 6 metals. The most useful methods for their preparation are based on the reaction of bidlithio) or bis(Grignard) reagents with metal carbonyl followed by 0-alkylation4 and Michael type addition of a-anions derived from group 6 carbene com+Departmentof Organic Chemistry. * Department of Solid State Chemistry. @Abstractpublished in Advance ACS Abstracts, October 1, 1995. (1)For the most recent review on synthetic applications oftransition metal carbene complexes, see: Hegedus, L. S. Transition Metals in the Synthesis of Complex Organic Molecules: University Science Books, Mill Valley, CA, 1994;pp 151-197. (2) For references concerning @-bis(carbene))homodimetalcomplexes of chromium, molybdenum, tungsten, manganese, rhenium, and iron see: (a) Macomber, D. W.; Hung, M.-H.; Madhukar, P.; Liang, M.; Rogers, R. D. Organometallics 1991,10,737and references 5-8 citated therein. (b) Macomber, D. W.; Hung, M.-H.; Verma, A. G.; Rogers, R. D. Organometallics 1988, 7, 2072. (c) Macomber, D. W.; Hung, J. Organomet. Chem. 1989,366,147. (d) Macomber, D. W.; Madhukar, P.; Rogers, R. D. Organometallics 1991, 10,2121. (e) Albrecht, T.; Sauer, J.; Noth, H. Tetrahedron Lett. 1994,35,561. (3)The only examples of the reactivity of @-bis(carbene)dimetal complexes mentioned in the literature are in ref 2b and: Hoa Tran Huy, N.; Lefloch, P. J. Organomet. Chem. 1988,344,303.
plexes to aS-unsaturated carbene complexes of group 6 elements.2a-c Alkylation of w-diiodoalkanes by a-anions derived from group 6 carbene complexes has also been de~cribed.~ A very efficient method for the preparation of chromium aminocarbene complexes is the reaction of Cr(C0)52- with tertiary amides in the presence of chlorotrimethylsilane.6 We have recently shown that this methodology can also be utilized for the preparation of iron aminocarbene complexes lacking a-hydr~gens.~ To the best of our knowledge, this method has never been used for the preparation of b-bis(aminocarbene))dimetal complexes. We have therefore studied the reaction of C~(CO)E,~and Fe(C0)d2- with diamides, (4)(a) Fischer, E.0.;Roll, W.; Hoa Tran Huy, N.; Ackermann, K. Chem. Ber. 1982,115,2951. (b) Quy Dao, N.; Fevrier, H.; Jouan, M.; Fischer, E. 0.;Roll, W. J. Organomet. Chem. 1984,275,191. (c) Hoa ”ran Huy, N.; Lefloch, P.; Robert, F.; Jeannin, Y. J. Organomet. Chem. 1987,327,211.(d) Anderson, D. M.; Bristow, G. S.; Hitchcock, P. B.; Jasim, H. A.; Lappert, M. F.; Skelton, B. W. J. Chem. SOC., Dalton Trans. 1987,2843. For recent example, see: Dumas, S.; Lastra, E.; Hegedus, L. S. J. Am. Chem. Soc. 1995,117,3368. (5) Macomber, D. W.; Madhukar, P. J. Organomet. Chem. 1992,433, 279. (6)(a) Imwinkelried, R.;Hegedus, L. S. Organometallics 1988,7, 702. (b) Schwindt, M. A.; Lejon, T.; Hegedus, L. S. Organometallics 1990, 9, 2814. (7) Dvofdk, D. Organometallics 1995,14,570.
0276-733319512314-5024$09.0010 0 1995 American Chemical Society
Organometallics, Vol. 14, No. 11, 1995 5025
(pBis(amin0carbene))dimetal Complexes Table 1. Carbene Complexes Prepared by Reaction of Cr(CO)s2-or Fe(C0)42-with Tertiary Diamides and Chlorotrimethylsilane amide
M
ratio M(CO),'W amide
1 2 3
la la la
Cr Fe Cr
4: 1 4: 1 1:l
4 5 6 7 8 9
lb Id le If
Cr Cr Fe Cr Cr Cr
4:l 4: 1 4: 1 4: 1 4: 1 4: 1
10
lg
Cr
4:l
11
3a
Fe
4:l
entry
IC IC
01
product (isolated yield, %) 2a (50.6) 2b (55.7) 2a (17.2) 3a (31.9) 3b (29.7) 2c (24.8) 2d (46.5) 3c (39.0) 3d (55.1) 2e (47.5) 3e (12.5) 2f (16.5) 3f (8.3) 4 (35.3)
Figure 1. Molecular structure of complex 4. Table 2. 'Selected Bond Lengths (A) and Bond Angles (deg) for Complex 4 Cr( 1)-C( 1) Cr(l)-C(3) Cr( 1)- C(5) Fe(l)-C(17) Fe(l)-C(19) Fe( 1)-C(2 1) 0(2)-C(2) 0(4)-C(4) 0(6)-C(18) 0(8)-C(20) N(U-C(6) N(1)-C(8) N(2)-C(16)
Scheme 1 1. M(C0);Me2NCOa C O N M e 2 la X 1b X IC X
2a 2b 2c 2d
X X X X
---
--
CH, 1,3 - subst. CH, 1,2 subst. N, 2,6 Subst.
-
-
CH, 1,3 - subst., M = Cr CH, 1,3 - subst., M = Fe N, 2,6 - subst., M = Cr N, 2,6 - subst., M Fe
2. Me3SICI
C
- -
M =Cr, n = 5 M Fe, n 4
3a X 3b X
--
CH, 1,3 - subst., M CH, 1,2 - subst., M
--
09
Cr Cr
-
aiming a t developing a new route for the preparation of fp-bis(amin0carbene))dimetalcomplexes of chromium and iron. We chose N,N,","-tetramethylisophthalamide (la) as a model compound for the reaction of diamides with chromium and iron carbonylate anions in the presence of chlorotrimethylsilane. Aromatic amides have no a-hydrogens, which is necessary for the successful preparation of the iron aminocarbene c~mplexes.~ Moreover the 1,3-disubstitution pattern causes no steric hindrance. By this choice we also hoped to avoid solubility problems, which are typical for the 1,4disubstituted aromatics. The reaction of diamide la with excess of Cr(C0)52in THF followed by addition of chlorotrimethylsilane ,(Scheme1)readily afforded the desired @-bis(aminocarbene))dichromium complex 2a in 50% yield (Table 1, entry 1). Under the same conditions,8 Fe(C0)42- gave the corresponding fp-bis(amin0carbene))diiron complex 2b in 55%yield (Table 1,entry 2). When l a was treated with C~(CO)E,~in 1:l molar ratio, besides the (u-bis(aminocarbene))dichromiumcomplex 2a, the aminocarbene 3a was also isolated in a modest yield (Table 1, entry 3). Interestingly, the latter complex can easily (8) It is necessary to use Fe(C0)d2-, prepared by reduction of Fe-
(C0)s with sodium naphthalenide in THF. The commercial product
solvated by dioxane is insoluble in THF and therefore useless for this reaction (cf. ref 7).
C(2)-Cr(l)-C(l) C(3)-Cr(l)-C(2) C(4)-Cr(l)-C(2) C(5)-Cr(l)-C(l) C(5)-Cr(l)-C(3) C(6)-Cr(l)-C(l) C(6)-Cr(l)-C(3) C(6)-Cr(l)-C(5) C(19)-Fe(l)-C(17) C(20)-Fe(l)-C(17) C(20)-Fe(l)-C(19) C(21)-Fe(l)-C(18) C(21)-Fe(l)-C(20) C(8)-N(l)-C(6) C(16)-N(2)-C( 15) C(17)-N(2)-C(16) C(9)-C(6)-Cr(l) N(2)-C(17)-Fe(l) C(13)-C(17)-N(2)
1.91(2) 1.90(2) 1.87(2) 2.00(1) 1.78(1) 1.79(2) 1.18(2) 1.18(2) 1.19(3) 1.16(2) 1.30(2) 1.45(2) 1.42(2) 91.0(6) 87.1(5) 173.2(7) 89.6i5j 88.5(6) 90.4(5) 91.6(5) 174.2(5) 89.2(5) 87.0(5) 120.8(7) 86.6(6) 91.0(6) 124.9(11) 112.7(10) 126.4(11) 113.8(8) 125.9(8) 116.8(10)
Cr(l)-C(2) Cr(l)-C(4) Cr( 1)-C(6) Fe(l)-C(18) Fe(l)-C(20) 0(1)-C(1) 0(3)-C(3) 0(5)-C(5) 0(7)-C(19) 0(9)-C(21) N(U-C(7) N(2)-C(15) N(2)-C( 17) C(3)-Cr(l)-C(l) C(4)-Cr(l)-C(l) C(4)-Cr(l)-C(3) C(5)-Cr(l)-C(2) C(5)-Cr(l)-C(4) C(6)-Cr(l)-C(2) C(6)-Cr(l)-C(4) C(18)-Fe(l)-C(17) C(19)-Fe(l)-C(18) C(20)-Fe(l)-C(18) C(21)-Fe(l)-C(17) C(21)-Fe(l)-C(19) C(7)-N(l)-C(6) C(8)-N(l)-C(7) C(17)-N(2)-C( 15) N(l)-C(6)-Cr(l) C(9)-C(6)-N(1) C(13)-C(17)-Fe(l)
1.87(1) 1.87(1) 2.15(1) 1.78(2) 1.76(1) 1.16(2) 1.17(2) 1.15(2) 1.11(2) 1.13(2) 1.47(2) 1.50(2) 1.32(2) 177.4(5) 92.1(6) 89.7(5) 88.8(6) 85.2(6) 97.0(5) 89.1(5) 93.3(5) 115.5(6) 123.7(7) 177.7(5) 92.9(6) 122.6(12) 112.4(10) 120.9(10) 130.8(9) 115.1(11) 117.2(8)
be converted to the mixed chromium-iron p-bidaminocarbene) complex 4 in 35% yield by the reaction with an excess of tetracarbonylferrate and chlorotrimethylsilane (Table 1, entry 11). The reaction of o-phthalic diamide lb with Cr(C0)52gave the monocarbene complex 3b as the only product even when excess of the carbonylate anion was employed (Table 1, entry 4). The steric bulk of Cr(C0)5 group apparently prevents reaction with the second amidic group. The structure of the mixed p-bidaminocarbene) complex 4 was confirmed by single-crystal X-ray crystallography. The molecular structure and atom-labeling scheme is presented in Figure 1,whereas selected bond distances and angles are summarized in Table 2. The complex 4 shows structural features typical for other aminocarbene complexes of chromiumg and ironlo with metal-carbene bonds perpendicular t o the plane of the (9) Schubert, U.Coord. Chem. Rev. 1984,55,261. (10)Huttner, G.; Gartzke, W. Chem. Ber. 1972,105,2714.
Havranek et al.
5026 Organometallics, Vol. 14,No. 11, 1995 benzene ring and with the bulky metallocarbonyl groups pointing t o the opposite faces of the aromatic ring. To establish the scope of the reaction we further turned our attention to binaphthyl-derived bis(amide1 Id, N,N,”,”-tetramethyl-2,6-pyridinedicarboxamide (IC), and amides of furane-2,5-dicarboxylic acid. The binaphthyl bidamidel Id behaved similarly to the o-phthalic diamide l b in the reaction with cr(c0)s2giving monocarbene complex 3c as the only carbene product (Table 1,entry 7). On the contrary, no carbene complex was formed in the reaction of bis(amide) Id with Fe(C0)d2-. Pyridine bis(amide) ICreacted readily with both Cr(C0)s2- and Fe(C0)d2- with formation of bidcarbene) complexes 2c in low and 2d in good yields (Table 1,entries 5 and 6). On the other hand, N,N,N’,N’tetramethyl-, N,N,”,”-tetrabutyl-, and the bis(morpholine) amide of furane-2,5-dicarboxylic acid failed to give any carbene product in reaction with both Fe(C0)d2and Cr(C0)52-.11 The @-bis(amin0carbene))dimetal complexes prepared from aromatic amides are yellow solids which decompose upon heating without melting. The lH-NMR spectra of these compounds show, as expected, two separate signals for the methyl groups of the N,Ndimethylamino substituent at 0 3.1 and 4.0 ppm, with the chemical shifts very similar for all the complexes prepared. For the aromatic region, a large upfield shift of the protons next to the carbene moiety is characteristic. This shift is 0.92 ppm for 4-H and 6-H and 1.37 ppm for the 2-H of the bidchromium carbene) complex 2a, which contrasts with the bis(amide) la, whose aromatic protons form a singlet at 7.45 ppm. For the bidiron aminocarbene) complex 2b, these values are somewhat lower (0.79 and 1.131, and the corresponding upfield shifts for the mixed complex 4 fall between those for 2a and 2b (0.80 and 0.87 ppm for the 4-H and 6-H and 1.26 ppm for the 2-H). At the same time the chemical shift of the aromatic proton in 5-position remains practically unchanged as for the starting bis(amide) l a (7.42 ppm). Similar effects can be seen in the 13CNMR spectra. Thus, for example, the aromatic carbons C-4 and C-6 in the bidchromium carbene) complex 2a have chemical shifts down a t 11.17 ppm and the C-2 even at 16.01 ppm compared to the corresponding amide la. At the same time, the change of chemical shift of C-5 is -= 1ppm. Similar but less profound effects in the NMR spectra of the monocarbene complexes of chromium are known12and were attributed to the steric interactions of an aromatic ring with the rest of the m01ecule.l~ Aliphatic diamides derived from oxalic14and malonic acids failed to give any isolable carbene product which,
-
(11)In principle, this unreactivity might be a result of low solubility in the case of tetramethyl bis(amide) and steric hindrance in the case of tetrabutyl bis(amide) of furane-2,5-dicarboxylic acid. But the failure to react with the bis(morpho1ide) of 2,5-furanedicarboxylic acid, which is reasonably soluble (approximately 2.5 g/100mL THF), together with the fact that morpholine amides of monocarboxylicacids react smoothly with both Cr(CO)& and Fe(C0)?2- (refs 6a and 7), indicates that the reason for the observed behavior is the presence of disubstituted furane itself. (12) Connor, J. A.;Jones, E. M.; Randall, E. W.; Rosenberg, E. J. Chem. SOC., Dalton Trans. 1972,2419. (13) For further discussion of this phenomenon, see also note 29 in: Aoki, S.;Fujimura, T.; Nakamura, E. J.Am. Chem. SOC. 1992,114, 2985. (14) [~-l,2-bis~diethylamino~ethanediylidene]bis(pentacarbonylchromium) is a known compound: Fischer, 0. E.; Wittmann, D.; Himmelreich, D.; Neugebauer, D. Angew. Chem., Int. Ed. Engl. 1982, 21,444.
Scheme 2 Me2NCO-(CH2)n-CONMe2
1. Cr(C0);2. Me3SICI
l e n - 2 ; I f 17-3; l g n - 4
( c 0 ) 5 c 6 ( C H2)n-CON Me2 Me2N 3d n - 2 ; 3e n - 3 ; 3f n - 4 X
OMe
CONMe2 4 Id X=O 3c X = (CO)&r
in the latter case, may be due to deprotonation of the malonic acid diamide by the relatively strongly basic Cr(CO)s2-. N,N,”,N’-Tetramethylsuccinamide (le)reacted similarly t o N,NJV’,”-tetramethylphthalamide (lb) to afford the monocarbene complex 3d as the only product (Scheme 2), even if a large excess of Cr(C0)s2was used (Table 1,entry 8). This is rather surprising, because diamide le is much more flexible than l b so that a smooth formation of the @-bis(amin0carbene))dichromium complex could be expected. N,N,”,”tetramethylglutaramide (If) gave a mixture of both bis(amin0carbene)dichromium complex 2e and monocarbene complex 3e with former as the main product (Table 1, entry 9). N,N,”,”-tetramethyladipamide (lg) behaved as expected, giving the @-bis(aminocarbene))dichromium complex 2f in moderate yield. A small amount of monocarbene complex 3f was also formed15 (Table 1, entry 10). The structure of our aliphatic chromium carbene complexes thus obtained is confirmed by the ‘H-NMR and IR spectra. In conclusion, the reaction of tertiary unhindered bis(amides) with cr(c0)s2- has been developed as a method for the preparation of @-bis(amin0carbene))dichromium complexes. Similarly, Fe(C0)d2- can be used for the preparation of @-bis(amin0carbene))diiron complexes from aromatic diamides. Experimental Section Melting points were determined on a Kofler block and are uncorrected. Unless otherwise noted, all lH NMR spectral (15)To confirm the surprising outcome that succinamide le gives exclusively monocarbene complex 3d while the analogous reaction of the adipamide lg gives predominantly the bidcarbene) 2f,a control experiment with an equimolar mixture of le and lg and 4 equiv of Cr(C0)s2- was done. Again no succinamide-derived bidcarbene) was formed. Interestingly, the yield of crude adipamamide-derived bis(carbene) 2f was higher (75%) compared to the nonmixed experiment in this case. This might be a result of the relatively higher amount of Cr(CO)& in the reaction mixture (only 1 equiv of Cr(C0)62- reacts with le).
(pBis(aminocarbeneJdimeta1 Complexes Table 3. Structure Determination Summary empirical formula fw temp, K diffractometer and radiation used scan technique cryst syst space group unit cell dimens, A a
b c
cell vol, A3
z
d(calcd),Mglm3 abs coef, mm-l abs conF(OO0) cryst dimens, mm no. of reflcns used for cell determination 0 range for reflctns used for cell determination, deg interval of std reflcns monitoring, min intensity fluctuation tot. no. of reflcns measd 20 range, deg h k 1
no. of unique reflcns obsd criterion for obsd reflcns function minimized weighting scheme params refined R, % Rw, % S max shift/esd max and min heights in final ~p map (e*A-3) programs used
Cz&&rFeNzOg 548.21 293
Organometallics, Vol. 14, No. 11, 1995 5027 Table 4. Fractional and Thermal Parameters (k) for Compound 4 atom
Enraf-Nonius CAD4, graphite monochromator, Cu Ka (3, = 1.5418 A) a129
orthorhombic p 2 12121 6.464(2) 13.373(1) 27.27(8) 2357(1) 4 1.545 9.29
W-scan 1112 0.8 x 0.5 x 0.2 15 35-40 120 -1% 3136 1-100 0 to 6 0 to 13 -27 to 27 2888 (Friedel pairs not merged) Z > 1.9641) w(lFoI - IFcI)'
Chebychev series based on FdFJmax) and Fo-Fc, scheme 1517
308 9.7 11.5 1.13 0.02 -0.92 to 0.72 SIR92,16 CRYSTALS17
data were recorded in CDC13 at 300 MHz and chemical shifts are reported relative t o TMS. 13CNMR spectra were recorded at 75.46 MHz. Elemental analyses were performed by the analytical departments of UOCHB-AVCR and Prague Technical University. All experiments were carried out under argon. Tetrahydrofuran was distilled from benzophenone ketyl under the nitrogen atmosphere prior to use. Iron pentacarbonyl, chromium hexacarbonyl, and chlorotrimethylsilane were obtained from Aldrich and used without further purification. Neutral aluminum oxide (Brockman I11 grade) and silica were obtained from Lachema. Amides la-d were prepared from acid chlorides and dimethylamine in ether. The yields are based on the starting amides.
X-ray Data Collection, Structure Determination,and Refinement for Compound 4. The single crystal suitable for the measurement was obtained by diffusion of pentane vapors into a toluene solution of 4 a t room temperature. All pertinent data are summarized in Table 3. Data were corrected for Lorentz-polarization factors. Due to a high absorption caused by the wavelength used for the measurement, and the presence of Cr and Fe atoms in the molecule, it was necessary to use a correction of absorption based on a 1/, scan of five reflections. The structure was solved by direct methods by the use of SIR92 program.16 Because of the nonsymmetry of the P212121 space group the Cr and Fe atoms show high (16) Altomare, A.; Burla, M. C.; Camalli, M.; Cascarano, G.; Giacovazzo, C.; Guagliardi, A.; Polidori, G. J.Appl. Crystallogr. 1994, 27, 435.
xla
vlb
zlc
u(iZ
0.5257(3) 0.3586(3) 0.711(3) 0.130(2) 0.340(2) 0.936(2) 0.689(2) 0.305(2) 0.028(2) 0.716(3) 0.152(3) 0.314(2) 0.570(1) 0.639(3) 0.281(2) 0.408(2) 0.77~32) 0.633(2) 0.431(2) 0.209(3) 0.274(2) 0.533(2) 0.712(2) 0.818(2) 0.760(2) 0.585(2) 0.470(2) 0.688(2) 0.535(2) 0.515(2) 0.328(2) 0.157(2) 0.572(2) 0.228(2)
0.6381(1) 1.1933(1) 0.4893igj 0.518(1) 0.7745(8) 0.749(1) 0.5132(9) 1.091(1) 1.162(1) 1.317(1) i.360(1) 0.7178(7) 1.0743(7) 0.545(1) 0.5639(9) 0.725(1) 0.709(1) 0.5609(9) 0.7347(9) 0.622(1) 0.7888(9) 0.8322(8) 0.8477(9) 0.937( 1) 1.0105(8) 0.9986(8) 0.9092(7) 0.986(1) 1.1475(9) 1.0803(7) 1.129(1) 1.1749(8) 1.2694(9) 1.296(1)
0.39444(7) 0.37119(6) 0.3209(5) 0.4065(4) 0.4735(4) 0.4041(6) 0.4785(5) 0.2752(4) 0.4409(5) 0.3952(7) 0.3220(5) 0.2978(4) 0.4485(4) 0.3482(6) 0.3983(5) 0.4420(6) 0.3984(5) 0.4459(6) 0.3357(4) 0.2898(5) 0.2589(4) 0.3362(4) 0.3067(5) 0.3107(5) 0.3413(4) 0.3694(4) 0.3662(4) 0.4672(5) 0.4854(4) 0.4021(4) 0.3143(7) 0.4147(5) 0.3851(6) 0.3427(5)
0.036(1) 0.035(1) 0.070(7) 0.073(6) 0.066(6) 0.080(7) 0.068(6) 0.067(7) 0.080(7) 0.088(9) 0.079(7) 0.043(5) 0.039(5) 0.048(8) 0.046(7) 0.051(8) 0.051(8) 0.049(7) 0.037(6) 0.055(7) 0.048(6) 0.034(5) 0.041(6) 0.049(7) 0.041(6) 0.038(6) 0.033(5) 0.048(7) 0.044(6) 0.032(5) 0.06(1) 0.032(6) 0.045(8) 0.049(7)
anomalous dispersion and therefore the Friedel pairs were not merged. Refinement of parameters was achieved by the program CRYSTALS7(full-matrix refinement with hydrogen atoms fmed in positions found for geometry U(iso) = U(eq) for the corresponding atom). The molecule 4 does not contain chiral centers, but the determination of the absolute configuration of the crystal should give the proper configuration of the molecules forming the studied crystal. However, the attempt to establish the absolute configuration by the refining of Flack's parameter was unsuccessful. The final value of Flack's parameter afier refinement was 0.45(2). Final atomic coordinates are collected in Table 4. NJV,iV',iV'-Tetramethylisophthalamide(la):lH NMR 6 2.96 (9, 6, CHs), 3.10 (s, 6, CH3), 7.45 (s, 4, ArH); 13CNMR 6 35.88 (9, CH3), 40.10 (q, CH3), 126.16 (d, C-arom), 128.67 (d, C-arom); 129.11 (d, C-arom), 137.14 (s, C-arom), 171.26 (s,
c-0).
(CO)SC~[C~-~,~-(C(NM~~))C~H~(C(NM~Z))IC~(CO (2a). To a suspension of chromium hexacarbonyl (2.2 g, 1 0 mmol) in THF (10 mL) was added a 0.78 M THF solution of sodium naphthalenide (32 mL, 25 mmol) at -78 "C via canula, and the mixture was allowed to warm to 0 "C. After stirring at this temperature for 0.5 h, a solution of N,N,","-tetramethylisophthalamide (0.55 g, 2.5 mmol) in THF (10 mL) was added, the reaction mixture was kept at 0 "C for another 0.5 h and then cooled to -78 "C, and then chlorotrimethylsilane (2 mL, 15.7 mmol) was added via syringe. The resulting mixture was stirred at -78 "C for 30 min and then allowed to warm slowly ( 1 h) to room temperature. Neutral alumina (8 g) was added, and the THF was evaporated. Chromatography on silica (130 g, hexane, then hexane-dichloromethane, 2 : l ) gave crude product (0.81 g). Crystallization (n-heptanedichloromethane) afforded 0.724 g (50.6%) of a yellow solid: 'H NMR 6 3.17 (9, 3, CH3), 4.00 (s, 3, CH3), 6.08 (s, 1,ArH), 6.53 (d, J = 7.2 Hz, 2, ArH),7.42 (t, J = 7.5 Hz, 1, ArH); 13C (17) Watkin, D. J. CRYSTALS, University of Oxford, 1990.
Havranek et al.
5028 Organometallics, Vol.14,No. 11, 1995 NMR 6 47.10 (9, CHd, 52.22 (9, CHd, 110.15 (d, C-arom), 117.50 (d, C-arom), 129.98 (d, C-arom), 153.88 (9, C-arom), 217.88 (s, cis CO), 224.15 ( 8 , trans CO), 274.16 ( 8 , C-Cr); IR (CC14)v 2053 (m), 1968 (m), 1936 (s), 1923 (s, sh) cm-l. Anal. Calcd for CzzH16CrzNz010:C, 46.17; H, 2.82; N, 4.89. Found: C, 45.96; H, 2.84; N, 4.95.
J = 8 Hz, 2, PyH), 7.77 (t,J = 8 Hz, 1, PyH); 13CNMR 6 47.73 (9, CH3), 51.97 (9, CH3), 113.69 (d, 138.07 (d, Py), 161.23 (s, Py),217.85 ( 8 , cis, CO), 224.20 ( 8 , trans CO), 271.16 (9,
m),
C=Cr); IR (CHC13) v 2054 (m), 1974 (w), 1932 (s) cm-'. Anal. Calcd for Cz1H1&r2N3010: C, 43.99; H, 2.64; N, 7.33. Found: C, 43.88; H, 2.79; N, 7.25.
(CO)rFe[lr-1,3-(C(NMe~))CsH4(C(NMez))lFe(CO)r (2b).
(CO)rFe[lr-2,6-(C(NMez))CaHsN(C(NMez))IFe(C0)4 (2d).
The same procedure as for 2a starting from Fe(CO)s (1.4 mL, 10 mmol), a 0.75 M THF solution of sodium naphthalenide (32 mL, 24 mmol), and diamide la (0.55 g, 2.5 mmol) gave after chromatography on neutral alumina (120 g) and cryetallization from an n-heptane-dichloromethane mixture 0.73 g (55.7%) of pure 2b: 'H NMR 6 3.19 (s, 6, 2CH3), 4.02 (9, 6, 2CH3), 6.32 (s, 1,ArH), 6.67 (d, J = 7.7 Hz, 2, ArH), 7.41 (t, 1, J = 7.7 Hz, ArH); 13CNMR 6 47.00 (9, CH3), 51.11 (9, CH3), 112.69 (d, C-arom), 118.94 (d, C-arom), 129.98 (d, C-arom), 154.13 (s, C-arom), 215.40 (9, CO), 258.54 (9, C-Fe); IR (CC14) v 2042 (m), 1970 (w), 1936 (s), 1927 (m, sh) cm-l. Anal. Calcd for CzoH16FezNz08:C, 45.84; H, 3.08, N, 5.35. Found: C, 46.06; H, 3.09; N, 5.32. (CO)aCr[C(NMe2)(3-(Me2NCO)CsH4)1 (3a). To a solution of CI(CO)~Z-, prepared by reduction of chromium hexacarbonyl (2.2 g, 10 mmol) with a 0.75 M THF solution of sodium naphthalenide (38 mL, 28.5 mmol) as described for 2a, was added a solution of bis(amide) la (2.2 g, 10 mmol) in THF (70 mL) at -78 "C. The mixture was allowed to warm to 0 "C, kept at this temperature for 0.5 h, and then again cooled t o -78 "C, and chlorotrimethylsilane (4 mL, 31.5 mmol) was added via syringe. The reaction mixture was allowed to warm to 0 "C, alumina (16 g) was then added, and THF was evaporated. The residue was suspended in n-hexane (50 mL) and transferred to the top of a column filled with 65 g of silica. Naphthalene was washed out by hexane, then bis(carbene) 2a (0.985 g, 17.2%) was eluted with n-heptane and dichloromethane (2:1), and finally 3a (1.266 g, 31.9%) was washed out by dichloromethane-ethyl acetate (2:l) mixture. Carbene 3a was a yellow oil, which solidified after several weeks in the refrigerator: mp 63-67 "C; lH NMR 6 2.98 (br S, 3, CH3 amide), 3.08 (s, 6, CH3 carbene), 3.11 (s, 3, CH3 amide), 3.99 (s, 3, CH3 carbene), 6.73 (9, 1, ArH), 6.78 (d, J = 7.7 Hz, 1, ArH), 7.21 (d, J = 7.7 Hz, l,ArH), 7.44 ( t , J =7.7 Hz, 1,ArH); IR (CC14)v 2054 (s), 1970 (m), 1932 (vs), 1641 (s) cm-'. Anal. Calcd for C1&6CI"z06: c, 51.51; H, 4.07; N, 7.07. Found: c , 51.53; H, 4.08; N, 7.36. (CO)~C~[C(NM~Z)(~-(M~ZNCO)C~H~)] (3b). The same procedure as for 2a starting from Cr(COI6 (2.2 g, 10 mmol), a 0.78 M THF solution of sodium naphthalenide (30 mL, 23.4 mmol), and diamide lb (0.55 g, 2.5 mmol) furnished 0.816 g of crude product, which gave, after crystallization from an n-heptane-dichloromethane mixture, 0.294 g (29.7%) of 3b: lH NMR 6 3.02 (s, 3, CH3 amide), 3.15 (s, 3, CH3 carbene), 3.16 (s, 3, CH3 amide), 3.92 (s, 3, CH3 carbene), 6.75 (d, J = 7.8 Hz, 1,ArH), 7.16 (t,J = 7.4 Hz, 1,ArH), 7.29 (d, J = 7.4 Hz, 1,ArH), 7.42 (t,J = 7.7 Hz, 1,ArH); IR v 2053 (w), 1983 (w), 1966 (w), 1934 (SI, 1919 (SI, 1637 (w) cm-'. Anal. Calcd for C17H16CrNZ06: C, 51.51; H, 4.07; N, 7.07. Found: C, 51.81; H, 4.14; N, 6.87. N ~ ~ ~ - T e t r a m e t h y l - 2 , 6 p y r i d i n e d i c (IC): arbo 'H NMR 6 3.04 (9, 3, CH3), 3.13 (9, 3, CH3), 7.65 (d, J = 7.8 Hz, 2,PyH), 7.88 (t, J = 7.6 Hz, 1,PyH); 13CNMR 6 36.33 (9, CH3), 39.64 (9, CH3), 124.62 (d, Py), 138.68 (d, Py),153.80 (s, Py),168.88 (s, C=O).
Fe(C0)6 (1.4 mL, 10 mmol) was added via syringe to a solution of sodium naphthalenide prepared from sodium (0.60 g, 26 mmol) and naphthalene (3.5 g, 27 mmol) in THF (50 mL) at -60 "C. The mixture was allowed to warm to 0 "C. After being stirred at this temperature for 15 min, the solution was cooled to -78 "C, amide IC (0.553 g, 2.5 mmol) in 15 mL of THF was added, and the mixture was allowed t o reach 0 "C and kept at this temperature for another 15 min. Then 20 mL of THF was added, the solution was cooled to -78 "C, and chlorotrimethylsilane (2.5 mL, 19.6 mmol) was added via syringe. The resulting mixture was allowed to warm to room temperature (1 h), neutral alumina (8 g) was added, and the THF was evaporated. Chromatography on alumina (150 g, n-heptane, n-heptane-dichloromethane, 2:l) gave 0.760 g of crude product, Crystallization from an n-heptane-dichloromethane mixture afforded 0.611 g (46.5%) of a yellow solid: 'H NMR 6 3.22 ( 8 , 3, CH3), 4.02 (5, 3, CH3), 6.90 (d, J = 7 Hz, 2, F'yH), 7.81 (t,J = 7 Hz, 1,PyH); 13CNMR 6 47.22 (q, CH3), 51.12 (9, CH3), 117.06 (d, C-F'y), 138.32 (d, C-Py), 166.84 (s, C-Py), 215.18 (s, CO), 255.10 (s, C-Fe); IR (CHC13) v 2042 (s), 1968 (m), 1939 (vs) cm-l. Anal. Calcd for C19H15FezN308: C, 43.47; H, 2.88; N, 8.00. Found: C, 43.28; H, 3.02; N, 7.94. Bis(amide) Id:Mp 210 "C (EtOH-HZO); lH NMR 6 2.96 3.20 (s,6, CH3), 3.35 (bs, 3, CH3), 3.68 (bs, 3, CH3), (~,6, 7.12-7.22 (m, 1,ArH), 7.24-7.32 (m, 3, ArH), 7.39-7.47 (m, 2, ArH), 7.87-8.01 (m, 4, ArH); 13C NMR u 35.55 (4, NCH3amide), 38.97 (9, NCHs-amide),62.09 (9, OCH3), 125.95 (d, Ar), 127.78 (d, Ar),128.89 (d, Ar), 130.81 (s, Ar), 134.73 (s, Ar), 170.01 (s, CO); IR (CHC13)v 3010 (m), 2942 (w), 2878 (w), 1627 (vs), 1501 (m), 1459 (m), 1398 (m), 1354 (w) cm-l. Anal. Calcd for CzsHz8Nz04.HzO: C, 70.87; H, 6.37; N, 5.90. Found: C, 70.49; H, 6.50; N, 5.81. Carbene Complex 3c. To the solution of cr(c0)5'-, prepared by reduction of chromium hexacarbonyl (0.88 g, 4 mmol) with a 0.80 M THF solution of sodium naphthalenide (13 mL, 10.4 mmol) as described for 2a,was added a solution of bis(amide) Id (0.456 g, 1 mmol) in THF at -78 "C. The mixture was allowed to warm to 0 "C, kept at this temperature for 0.5 h, and then again cooled t o -78 "C, and chlorotrimethylsilane (0.8 mL, 6 mmol) was added via syringe. The reaction mixture was allowed to warm to 0 "C, alumina (4 g) was added, and THF was evaporated. Chromatography of the residue on silica (30 g) using gradually n-heptane, n-heptane-dichloromethane (2:l and l:l), and finally dichloromethane-ethylacetate (1:l)mixtures gave crude 5, which was further purified by chromatography on silica using an n-heptane-etheracetone-methanol (50:30:17:3) mixture. By this way 0.27 g (39%)of carbene 5 was obtained as a clathrate with n-heptane in the form of yellow crystals: Mp 192-195 "C; lH NMR 6 0.88 (t,J = 7 Hz, 3, CH3-heptane), 1.27 (bs, 5, CHz-heptane), 2.94 (bs, 3, NCH3-amide), 3.19 (s, 3, CH3), 3.21 (s, 3, CH3), 3.22 (s, 3, CH3), 3.43 (bs, 3, NCH3-amide),4.05 (s, 3, NCH3-carbene), 6.95-7.25 (m, 2, ArH), 7.3-7.5 (m, 4, ArH), 7.8-8.05 (m, 4, ArH); 13C NMR (selected signals) 6 14.74 (9, CH3-heptane), 23.32 (t, CHz-heptane), 29.63 (t, CHz-heptane), 32.51 (t,CHZheptane), 35.69 (9, NCH3-amide),39.07 (9, NCH3-amide),46.35 (9, NCHa-carbene), 51.82 (q, NCH3-carbene), 60.61 (q, OCHs), 62.08 (9, OCH3), 169.97 ( 8 , CON(CH&), 218.22 (s, cis CO), 224.22 (9, trans CO), 271.84 (s, C=Cr); IR (CHC13)v 2053 (m), 1971 (w), 1928 br (s), 1627 (w) cm-'. Anal. Calcd for 2C33H28CrN208*C,H16: C, 64.22; H, 5.32; N, 4.10. Found: C, 64.07; H, 5.32; N, 4.09. (CO)aCr[C(NMe~)((CHz)zCONMe~)l (3d). The same procedure as for 2a was used, starting from Cr(CO)6 (2.2 g, 10 mmol), a 0.78 M THF solution of sodium naphthalenide (32
(CO)sCr[lr-2,6-(C(NMez))CsHsN(C(NMez))ICr(CO)a (2~). The same procedure as for 2a starting from Cr(C0)e(2.2 g, 10 mmol), a 0.78 M THF solution of sodium naphthalenide (32 mL, 25 mmol), and diamide IC (0.553 g, 2.5 mmol) in 20 mL of THF gave after chromatography on silica (70 g, n-heptane, n-heptane-dichloromethane, 1:1 mixture) 0.380 g of crude product. Further purification by radial-layer chromatography (Chromatotron) under argon (heptane, ether, acetone, methanol, 50:30:17:3) afforded 0.355 g (24.8%) of pure 2c as yellow crystals: lH NMR 6 3.21 (6, 3, CH3), 4.00 (s, 3, CH3), 6.62 (d,
(pBis(amin0carbene))dimetal Complexes
Organometallics, Vol. 14, No. 11, 1995 5029
with a 1:l dichloromethane-ethyl acetate mixture and purification by radial-layer chromatography (Chromatotron) under argon (heptane, ether, acetone, methanol, 50:30:17:3) 0.078 g (8.3%) of a yellow oil containing according to the 'H NMR mainly monocarbene complex 3f was obtained: 'H NMR 6 1.47 (m, 2, CHz), 1.75 (m, 2, CHz), 2.37 (m, 2, CHd, 2.93 (s, 3, CHd, 3.00 (s, 3, CHd, 3.06 (m, 2, CHd, 3.33 (s, 3, CH3), 3.81 (s, 3, CH3). (CO)sCr[lr-l,3-(C(NMe2))CsH4(C(NMea))lFe(CO)r (4). To a solution of Fe(C0)E (0.4 mL, 3 mmol) in THF (20 mL) was added a 0.78 M THF solution of sodium naphthalenide (9.5 mL, 7.4 mmol) at -78 "C. The mixture was allowed to warm to 0 "C, kept a t this temperature for 30 min, and then cooled (CO)SC~[~~-(C(NM~~))(CH~)S(C(NM~~))IC~(CO)S (2e)and to -78 "C, and the carbene complex 3a (0.6 g, 1.5 mmol) in THF (5 mL) was added. The reaction mixture was then (CO)aCr[C(NMez)(CH2)sCONMe2] (3e). The same procedure as for the preparation of 2a starting from Cr(CO)6 (2.2 g, 10 allowed to warm t o 0 "C, kept at this temperature for 30 min, mmol), a 0.78 M THF solution of sodium naphthalenide (32 and then cooled again to -78 "C, and chlorotrimethylsilane (2 mL, 15.7 mmol) was added via syringe. The mixture was mL, 25 mmol), diamide If (0.46 g, 2.5 mmol), chlorotrimethylsilane (2 mL, 15.7 mmol), and A1203 (8g) afforded upon allowed to warm to 0 "C, alumina (4 g) was added, and the chromatography on silica (70 g, n-heptane, n-heptane-dichlosolvent was evaporated in vacuo. Chromatography on alumina romethane, 2:l) 0.682 g of crude 2e. Crystallization from an (50 g, n-hexane, n-hexane-dichloromethane, 2: 1) gave crude n-heptane-dichloromethane mixture gave 0.64 g (47.5%) of 4 (0.46 g, 55%). Crystallization from an n-heptane-dichlopure bis(carbene) complex 2e as a yellow solid: 'H NMR 6 1.49 romethane mixture yielded pure 4 (0.295 g, 35.3%) as a yellow (m, 2, CHz), 3.18 (m, 4, 2CHz), 3.37 (8, 6, 2CH3), 3.85 (s, 6, solid: lH NMR 6 3.16 (s, 3, CH3), 3.19 (8, 3, CH3), 4.01 (s, 6, 2CH3); IR (CHC13) Y 2052 (m), 1987 (w), 1921 (8) cm-l. Anal. 2CH3), 6.19 (s, 1,ArH), 6.58 (d, J = 7.6 Hz, 1, ArH), 6.65 (d, Calcd for ClgH&rzNz010: C, 42.39; H, 3.37; N, 5.20. Found: J = 6.2 Hz, 1,ArH), 7.42 (m, 1, ArH); 13C NMR 6 46.87 (9, C, 42.07; H, 3.42; N, 5.17. Crude monocarbene complex 3e CH3), 47.18 (9, CH3), 51.07 (q, CH31, 52.24 (q, CHd, 111.39 (d, was obtained by further elution with a 1:l dichloromethaneC-arom), 118.14 (d, C-arom), 118.31 (d, C-arom), 129.95 (d, ethyl acetate mixture as a yellow oil, which was purified by C-arom), 153.65 (s, C-arom), 154.20(s, C-arom), 215.44 (5, C-0 radial-layer chromatography (Chromatotron) under argon (Fe)), 218.00 (s, cis CO (Cr)),224.04 (s, trans CO (Cr)),258.86 (heptane, ether, acetone, methanol, 50:30:17:3). By this way (9, C=Fe), 273.86 (s, C-Cr); IR (cc4)Y 2054 (w), 2043 (w), 0.114 g (12.5%) of yellow oil was obtained: lH NMR 6 1.72 (m, 1970 (w), 1931 (s), 1925 (s, sh) cm-l. Anal. Calcd for C21H162, CHz), 2.44 (m, 2, CHz), 2.95 (s, 3, CH3), 3.02 (9, 3, CHd, CrFeNzOg: C, 45.99; H, 2.94; N, 5.11. Found: C, 46.04; H, 3.00; 3.10 (m, 2, CHz), 3.50 (s, 3, CH3), 3.82 (8,3, CH3); IR (CHC13) N, 5.18. Y 2052 (m), 1966 (w), 1922 (s), 1638 (w) cm-l. Anal. Calcd for C14H18CrNZ06: C, 46.41; H, 5.01; N, 7.73. Found: C, 46.55; Acknowledgment. Support of this research under H, 5.20; N, 7.58.
mL, 25 mmol), diamide l e (0.46 g, 2.5 mmol), chlorotrimethylsilane (2 mL, 15.7 mmol), and A1203 (8 g). Elution with n-hexane followed by a dichloromethane-ethyl acetate mixture gave 0.48 g (55.1%) of 3d as a yellow oil, which solidified to a yellow product: mp 65-69 "C dec; 'H NMR 6 2.44 (br S, 2, CHz), 2.96 (s, 3, CH3 amide), 3.04 ( e , 3, CH3 amide), 3.38 (s, 5, CH3 carbene CHz), 3.85 ( 6 , 3, CH3 carbene); IR (CHC13) Y 2054 (w), 1969 (w), 1924 (s), 1639 (m) cm-l. Anal. Calcd for C1&&rN~06:C, 44.82; H, 4.64; N, 8.05. Found: C, 44.64; H, 4.82; N, 7.76. N,.",iV'-Tetramethylglutaramide (10: lH NMR 6 1.94 (quin, J = 7 Hz, 2, CHd, 2.41 (t, J = 7 Hz, 4, 2CHz1, 2.92 (s, 3, CH3), 3.01 ( 8 , 3, CH3).
+
(CO)~Cr[lr-(C(NMez))(CH2)r(C(NMe2))lCr(CO)a (20 and (CO)&r[C(NMe2)(CH2)&ONMe2] (30. The preparation of 2a used Cr(CO)6 (2.2 g, 10 mmol), a 0.78 M THF solution of sodium naphthalenide (32 mL, 25 mmol), diamide l g (0.475 g, 2.5 mmol), chlorotrimethylsilane (2 mL, 15.7 mmol), and (8 g) and afforded upon chromatography on silica (70 g, n-hexane, n-hexane-dichloromethane, 2:l) and crystallization (n-heptane, dichloromethane) 0.228 g (16.5%) of 2f. Carbene 2f was isolated as a light yellow solid: lH NMR 6 1.53 (s, 4, 2CHz), 3.10 (9, 4, 2CHz), 3.32 (s,6, 2CH3), 3.84 ( 8 , 6, 2CH3); IR (CHC13)Y 2057 (w), 1979 (w), 1927,1885 (91, 1641 (w), 1543 (w) cm-l. Anal. Calcd for CzoHzoCrzNzOlo:C, 43.48; H, 3.65; N, 5.07. Found: C, 43.51; H, 3.82; N, 5.34. By further elution
Grant 203/95/0160from the Czech Grant Agency is gratefully acknowledged. We also thank the Prague Institute of Chemical Technology and the Institute of Organic Chemistry and Biochemistry-AVCR for their support of our program.
A1203
Supporting Information Available: Tables of anisotropic thermal parameters, complete bond lengths and bond angles, and complete fractional and thermal parameters for compound 4 (8 pages). Ordering information is given on any current masthead page. OM950258B
