Organometallics 1995,14, 1732-1738
1732
Reactivity of the Diruthenium(1)Diphosphine- and Acetate-Bridged Species [Ruz(C0)4@-02CMe) @-DPPM)21 [BF4I Kom-Bei Shiu,* Wei-Ning Guo, and Tsung-Jung Chan Department of Chemistry, National Cheng Kung University, Tainan, Taiwan 701, Republic of China
Ju-Chun Wang and Lin-Shu Liou Department of Chemistry, Soochow University, Taipei, Taiwan 111, Republic of China
Shie-Ming Peng and Ming-Chu Cheng Department of Chemistry, National Taiwan University, Taipei, Taiwan 106, Republic of China Received September 6, 1994@
Reactions of the cationic singly bridged A-frame complex [RU~(CO)~C~-O~CM~)C~-DPPM)~I+ (2)with I-, N3-, and Pz'-, via HPz'Et3N (HPz' = 3,5-dimethylpyrazole),in MeOH yield two types of neutral dibridged A-frame products, [RU~(CO)~C~-CO)C~-X)XC~-DPPM)~I (X = I (3), N3 (4)) and [RU~(CO)~~~-PZ')HC~-DPPM)~I (10). Complexes 3,4, and 10 have been characterized by spectroscopic data and X-ray crystallography: 3*Et20,a = 12.779(4) b = 27.447(11)A,c = 15.487(4) A, p = 95.676(23)", V = 5405(3) A3, monoclinic, P21/c; 2 = 4, refined to R = 0.041, R, = 0.034, and GOF = 1.33; 4CHzC12, a = 19.764(2) A,b = 14.647(2) c = 20.033(2) A,p = 97.532(8)", V = 5749(1) A3, monoclinic, P21/c; 2 = 4, refined to R = 0.058, R, = 0.086, and GOF = 1.16; leCH2C12, a = 13.046(2)A, b = 15.179(3) c = 28.226(5) A, p = 95.93(1)", V = 5559(1) A3, monoclinic, P2&, 2 = 4,refined to R = 0.074, R, = 0.081, and GOF = 1.70. The Ru-Ru distance is 3.0147(15) in 3, 3.020(1) in 4, and 2.891(3) in 10. Complex 3 reacts with PMe3 and P(OMe)3 to give [RU~(CO)~I~(PM~~)C~-DPPM)~~ (8) and [Ruz(CO)&{P(OMe)3}(pDPPM)21(9),respectively, whereas no reaction between 4 and these phosphine ligands was observed even under forcing conditions. This difference in reactivity, accompanied with the spectral evidences of 8 and 9, reflects apparently the greater importance of a facile switch from a bridging to terminal group relative to the cleavage of the dative Ru-Ru bond in the double-bridged A-frame complexes such as 3 and 4 to form isolable adducts such a s 8 and 9.
A,
A,
A,
A
A
A
Scheme 1
Introduction Binuclear complexes of two bridging bis(dipheny1phosphinolmethane (DPPM) ligands with a singly bridged A-frame geometry (I) have recently attracted a significant amount of interest because of their rich chemistry and potential as catalysts, catalyst precursors, or model compounds to study the metal-metal cooperativity effects in binding and activation of s u b ~ t r a t e s . l One -~
I\
important focus of many of these studies has centered on the binding of small molecules, either at endo (i.e. bridging) or ex0 (i.e. terminal) sites of the complexes. t a Abstract
published in Advance ACS Abstracts, March 15,
1995. (l)Puddephatt,R. J. Chem. SOC.Rev. 1983,12, 99.
In this regard, rarely encountered cationic complexes (1)are more intersuch as [Rh201-Cl)(C0)201-DPPM)21+ esting than the numerous neutral species, for 1 displays (2) Balch, A. L. In Homogeneous Catalysis with Metal Phosphine Complexes; Pignolet, L.H., Ed.; Plenum: New York,1983;pp 167-213. (3) Chaudret, B.;Delavaux, B.; Poilblanc, R. Coord. Chem. Reu. 1988,86, 191.
0276-733319512314-1732$09.00/00 1995 American Chemical Society
An Ru$ Diphosphine- and Acetate-Bridged Species
Organometallics, Vol. 14,No. 4,1995 1733
Table 1. Selected Bond Lengths (A)and Angles (deg) for 3, 4, and 10 Ru(l)-Ru(2) Ru( 1)-1(2) Ru( 1)-C( 1) Ru(2)-C( 1) Ru(1)-P(l) Ru(2)-P(2) C(1)-0(1) C(3)-0(3) Ru(l)-I(2)-Ru(2)
Figure 1. Perspective drawing with 30% probability ellipsoids and numbering scheme (only the ipso carbon atom of each phenyl group has been retained for clarity) for 3.
Ru(l)-C(2)-Ru(2) N(l)-N(2)-N(3)
substrate-dependent reactivity; SO2 enters the symmetry-allowed5 endo pocket, whereas 13C0 chooses the ex0 addition to produce doubly bridged A-frame complexes (Scheme 1L6 In this paper, we present the following new information: (1)reactions of the cationic singly bridged A-frame complex [ R u ~ ( C O ) ~ ( ~ - O ~ C M ~ ) ~ - (2I7with D P P M )dif~~+ ferent halide and pseudohalide anions, yielding two types of neutral doubly bridged A-frame products with the entering groups a t both sites, (2) reactivity of two dimeric products with a Ru-Ru distance longer than 3.0 A toward PR3 (R = Me, OMe, Ph) and (3) the X-ray structures of three reaction products obtained from 2.
Results and Discussion The cation-anion annihilation reactin between 2 and iodide did not occur at ambient temperature. However,
-
Ru(l)-N(I)-N(2) R~(l)-C(2)-0(2) C(2)-Ru(l)-C(l)
+ xS. HPz’ / E13N
.co - E1,NH’MeCO; O W p PC
v (10)
96.4(4) 177.9(14)
C(l)-Ru( 1)-N(1) Ru(l)-N(l)-Ru(2) N(4)-N(5)-N(6)
114.9(2) 151.4(22) 100.2(12)
N(l)-N(2)-Ru(2) C(l)-Ru(l)-N( 1) C(3)-Ru(2)-N(2)
2.7674( 15) 2.7556( 15) 1.847(12) 1.879(12) 2.426(3) 2.328(3) 1.141(14) 155.2(4) 91.9(4) 2.342(2) 2.167(8) 1.981(9) 2.380(3) 2.166(9) 1.844(10) 1.109(18) 1.136(15) 1.192(11) 173.0(4) 88.0(3) 175.1(11) 2.526(7) 2.260(18) 1.742(25) 2.54 l(7) 1.673(23) 1.235(28) 1.470(34) 1.398(30) 1.22 l(32) 1.058(27) 107.1(13) 134.8(9) 168.6(9)
when the mixture of the two ions was heated under reflux, an orange-red precipitate of 3 gradually formed. Two iodide ions were needed for a complete conversion of every cation 2 into [Ru~(CO)~~~-CO)(~-I)I~~-DPP (3). The single-crystal X-ray diffraction structure of this
MeCO,‘
*
C(3)-Ru(2)-1(2) Ru(l)-C(l)-Ru(2)
(c) Compoc 2.891(3) 2.536(7) 1.788(27) 2.5 12(7) 1.993(17) 1.346(24) 1.354(29) 1.277(30) 1.485(30) 1.119(32)
Scheme 2
+ X.
65.38(3)
(b) Compound 4 3.020( 1) Ru(1)-P(l) 2.344(2) Ru( 1)-N( 1) 1.855(11) Ru( 1)-C(2) 2.388(3) Ru(2)-P(4) 2.181(7) Ru(2)-N(4) 2.071(9) Ru(2)-C( 3) 1.178(13) N(2)-N(3) 1.202(13) W)-N(6) 1.147(14) C(2)-0(2) 1.133(13)
C
C
(a) Compound 3 3.0147(15) Ru( l)-I(l) 2.8252( 15) Ru(2)-1(2) 2.179( 10) Ru(l)-C(2) 2.014( 10) Ru(2)-C(3) 2.408(3) Ru(l)-P(3) 2.344(3) Ru(2)-P(4) 1.069(12) C(2)-0(2) 1.056(14)
1734 Organometallics, Vol. 14,No. 4, 1995
Shiu et al.
Q
cor,
a511
Figure 2. Perspective drawing with 30% probability ellipsoids and numbering scheme (only the ipso carbon atom of each phenyl group has been retained for clarity) for 4.
COMe){pu-Me2PCH2PMe2}21+ and then reacts with
Cl2lI f%
Y
c1411
C1311
0111
0131
another iodide anion to yield one CO and 3 (Scheme 2). It is also possible that 3 can be prepared from reaction of the related complex [Ru~(CO)~(,~-I)~(,~-DPPM)I (719 with DPPM. From Table 1, it is clear that the bridging iodide and carbonyl ligands are also unsymmetrically placed (Ru(l)-I(2) = 2.8252(15) Ru(2)-1(2) = 2.7556(15) A; Ru(l)-C(l) = 2.179(10) A; Ru(2)-C(l) = 2.014(10) A). Such a feature was observed previously in 1.6 Since either terminal iodide or carbonyl ligands are connected with Ru a t a short distance of 2.7674(15) for Ru(1)-I, 1.847(12)A for Ru(l)-C(2), and 1.879(12) A for Ru(2)-C(3), it is quite obvious that 3 has the two weak bridges Ru(l)-C(l)and Ru(1)-1(2). Two ruthenium atoms in 3 are separated by a distance of 3.0147(15) with one trigonal-bipyramidal and one octahedral Ru center. This value is much larger than that of 2.821(1)A in 6 or that of 2.7074(6) A in 7. The multiplicity of phosphorus signals observed in a 31P(1H} NMR spectrum reflects that 3 is diamagnetic. Conventional electron counting would predict a single Ru-Ru bond for this 34-electron species, and the long Ru(l)-Ru(2) bond may be classified as a dative bond, donating an electron pair from the 18-electron Ru(1) center to the 16-electron Ru(2) center.1° Apparently 3 has also a weak Ru-Ru bond, despite the two weak bridges. Reactivity of this complex toward Lewis bases such as phosphine ligands PR3 was hence studied. Complex 3 reacts as expected with PR3 to produce the adducts [Ruz(C0)312(PR3)CU-DPPM)21(R = Me (81, OMe (9)). Each
A;
A
A
CllOI PI:
Cl611 CIS11
b
v c1711
Figure 3. Perspective drawing with 30% probability ellipsoids and numbering scheme (only the ipso carbon atom of each phenyl group has been retained for clarity) for 10.
product then revealed that it is a doubly bridged A-frame complex with an unsymmetrical disposition of two iodide groups (Figure 1). Presumably, 2 reacts with (5), one iodide anion to give [Ru~(CO)~CU-I)(~-DPPM)~I+ having a structure similar to that of [Ru2(C0)4(pL(4)Parshall, G. W.; Ittel, S. D. Homogeneous Catalysis: The Applications and Chemistry of Catalysis by Soluble Transition Metal Complexes, 2nd ed.; Wiley: New York, 1992. ( 5 ) Hoffman, D. M.; Hoffmann, R. Inorg. Chem. 1981,20,3543.
~
(6)(a) Cowie, M.; Mague, J . T.; Sanger, A. R. J . A m . Chem. SOC. 1978,100, 3628. (b) Mague, J. T.; Sanger, A. R. Inorg. Chem. 1979, 18, 1224. (c) Sanger, A. R. J . Chem. SOC.,Dalton Trans. 1981,221. (7) Sherlock, S. J.; Cowie, M.; Singleton, E.; S t e p , M. M. d. V. Organometallics 1988,7,1663. ( 8 ) Johnson, K. A.; Gladfelter, W. L. Organometallics 1990,9,2101. (9) Colombie, A.; Lavigne, G.; Bonnet, J.-J. J . Chem. SOC.,Dalton Trans, 1986,899.
An Ru$ Diphosphine- and Acetate-Bridged Species
Organometallics, Vol. 14, No. 4, 1995 1735
Table 2. Fractional Atomic Coordinates and Be, Values“ for 3
(1
X
Y
Z
Be,
0.18664(7) 0.32567(8) 0.17294(8) 0.38749(7) 0.10642(23) 0.26658(23) 0.27 135(24) 0.41647(24) 0.1826(8) 0.1253(5) 0.0550(9) -0.0246(6) 0.3404(9) 0.3536(7) 0.2006(9) 0.4056(8) -0.0053(8) -0.0423(9) -0.1279( 10) -0.1790( 10) -0.1465(9) -0.0602( 8) 0.0470(9) 0.0738(9) 0.0189(11) -0.0637( 10) -0.0888( 10) -0.0350(9) 0.1750(8) 0.1535(9) 0.0801(9) 0.0268(9) 0.0486(9) 0.1229(8) 0.3742(8)
0.85946(3) 0.9 1693(3) 0.77178(3) 0.82811(3) 0.82323(11) 0.87344( 11) 0.90176(11) 0.95549( 12) 0.9287(4) 0.95718(24) 0.8698(4) 0.8740(3) 0.9737(4) 1.0048(3) 0.8 160(4) 0.9231(4) 0.8519(4) 0.8332(4) 0.8531(5) 0.8927(5) 0.9106(4) 0.8907(5) 0.7624(4) 0.7236(4) 0.6814(5) 0.6752(5) 0.735(5) 0.7568(5) 0.9023(4) 0.8803(4) 0.9013(5) 0.942 1(4) 0.9639(4) 0.9440(4) 0.8562(4)
0.25731(6) 0.14830(6) 0.34373(6) 0.2 1896(5) 0.12539(19) 0.02256( 19) 0.38283( 19) 0.26690( 19) 0.1883(6) 0.1817(4) 0.2935(8) 0.3202(6) 0.0828(7) 0.0452(5) 0.0432(7) 0.3693(7) 0.0625(7) -0.0177(7) -0.0661 (7) -0.0325(8) 0.0458(8) 0.0938(7) 0.1300(7) 0.0805(8) 0.07777(8) 0.1298(9) 0.1811(9) 0.1803(8) -0.0590(7) -0.1421(7) -0.2019(8) -0.18 17(7) -0.1023(7) -0.0408(7) -0.0396(7)
1.89(4) 1.94(4) 4.08(4) 2.78(4) 2.06( 14) 1.91(13) 2.23( 14) 2.30( 14) 1.6(5) 2.1(3) 3.4(6)
+
Be, = s / 3 n z ( U l ~ ( n a * ) 2&(bb*)*
5.0(5)
3.0(6) 3.7(4) 2.4(5) 2.0(5) 1.9(5) 2.8(5) 3.9(7) 4.1(7) 3.2(6) 2.8(6) 2.1(5) 3.2(6) 4.3(7) 4.7(8) 4.4(7) 3.4(6) 2.0(5) 2.9(6) 3.5(6) 2.9(6) 2.8(6) 2.3(5) 2.2(5)
C(22B) C(23B) C(24B) C(25B) C(26B) C(31A) C(32A) C(33A) C(34A) C(35A) C(36A) C(31B) C(32B) C(33B) C(34B) C(35B) C(36B) C(41A) C(42A) C(43A) C(44A) C(45A) C(46A) C(41B) C(42B) C(43B) C(44B) C(45B) C(46B) C(51) C(52) O(53) C(54) C(55)
X
Y
Z
Be.
0.4381(10) 0.5176(10) 0.5353( 10) 0.4707( 10) 0.3912(9) 0.2108(9) 0.1 160(9) 0.0704( 11) 0.1272(14) 0.2257(12) 0.2654( 11) 0.3001(9) 0.2584(10) 0.2874( 11) 0.3559( 11) 0.3972(11) 0.3719(10) 0.3855(9) 0.2989(9) 0.2743(9) 0.3402( 11) 0.4263( 10) 0.4502(9) 0.5570(8) 0.6034(10) 0.7084(12) 0.7715(10) 0.7300(10) 0.6245(9) 0.2983(19) 0.234(3) 0.3175(12) 0.323318) 0.3224(24)
0.8921(4) 0.881 l(5) 0.8346(5) 0.7983(5( 0.8095(4) 0.9583(4) 0.9743(4) 1.0177(5) 1.0433(5) 1.0292(6) 0.9860(5) 0.8692(4) 0.8799(5) 0.8550(6) 0.8172(5) 0.8049(4) 0.8304(5) 1.0180(4) 1.O412(4) 1.0880(4) 1.1122(4) 1.0913(4) 1.0433(4) 0.9585(4) 0.9988(5) 1.0005(6) 0.9630(5) 0.9220(5) 0.9205(4) 0.3132(8) 0.2761(10) 0.2627(6) 0.2120( 10) 0.2187( 10)
-0.0668(9) -0.1171(9) -0.1432(9) -0.1 168(9) -0.0668(8) 0.4179(7) 0.3835(8) 0.413 l(9) 0.4764( 10) 0.5093( 10) 0.4805(9) 0.4846(7) 0.5605(8) 0.6357(8) 0.6364(8) 0.5645(9) 0.4872(8) 0.2954(7) 0.2569(8) 0.2800(8) 0.3402(8) 0.3810(9) 0.3594(8) 0.2598(7) 0.2255(10) 0.2167(11) 0.2420(9) 0.2723 10) 0.2825(8) 0.0519(14) 0.095(4) -0.0327( 13) -0.0974( 22) -0.2 17(4)
4.2(7) 4.9(8) 4.8(8) 4.37) 3.5(6) 2.5(5) 3.1(6) 5.5(8)
7.0(10) 6.3(9) 5.0(8) 2.7(6) 4.3(7) 6.2(10) 5.0(7) 4.6(7) 4.1(7) 2.6(6) 2.8(6) 3.6(6) 4.0(7) 4.2(7) 3.5(6) 2.4(5) 4.9(8) 6.6(9) 4.9(8) 5.2(8) 3.6(7) 13.8(18) 39.0(53) 18.2(15) 2 1.0(27) 46.3(64)
+ U13(cc*)*+ 2Ulza~*bb(cosy ) + 2U130~*cc*(cosp) + 2Uz~bb*cc*(cosa)).
adduct displays three carbonyl stretching bands in CH2Clz with one band a t the lowest frequency of 1742 cm-l for 8 and 1826 cm-l for 9, indicating that 8 and 9 may retain the carbonyl bridge or semibridge,ll but whether the iodide bridge or the Ru-Ru bond is cleaved in these adducts should be the subject of a further structural analysis. Since there is an open terminal site around Ru(2), it appears probable that an initial terminal attack of PR3 will occur, leading to the formation of the adducts with cleavage of either the Ru-Ru dative bondlo or the weak iodide bridge. The fact that 2 fails to react with PPh3 is probably due to the steric nature of this phosphine ligand. Reaction of 1with azide follows similarly to give [Ruz( C ~ ) Z ~ ~ - C O ~ - N ~ ) ( N ~ ) ~(4). ~-D The P Pbridging M ) Z I azide group adopts an end-on coordination mode with LN(l)-N(2)-N(3) = 177.9(14)”(Figure 21, though it is able to bridge the metals in an end-to-end mode.12 To the best of our knowledge, 4 is the first dinuclear carbonyl (10)(a) Langebach, H.-J.; Vahrenkamp, H. Chem. Ber. 1979,112, 3390,3773.(b) Breen, M.J.;Duttera, M. R.; GeofTroy, G. L.; Novotnak, G. C.; Roberts,D. A.; Shulman, P. M.; Steinmetz, G. R. Organometallics 1981,1, 1008. (c) Roberts, D. A.; Steinmetz, G. R.; Breen, M. J.; Shulman, P. M.; Morrison, E. D.; Duttera, M. R.; DeBrosse, C. W.; Whittle, R. R.; GeofTroy, G. L. Organometallics 1983, 2, 846. (d) Mercer, W. C.; Whittle, R. R.; Burkhardt, E. W.; Geoffroy, G. L. Organometallics 1986,4,68. (e) Shyu, S.-G.; Wojcicki, A. Organometallics 1985,4,1457.(0Powell, J.;Coutoure, C.; Gregg, M. R. J.Chem. SOC.,Chem. Commun.1988,1208. (g) Baker, R. T.; Calabrese, J . C.; Krusic, P. J.; Therien, M. J.; Trogler, W. C. J . Am. Chem. SOC.1988, 110,8392.(h) Jenkins, H. A.; Loeb, S. J.; Stephan, D. W. Inorg. Chem. 1989,28,1998. (i) Powell, J.; Sawyer, J. F.; Stainer, M. V. R. Inorg. Chem. 1989,28,4461. Shyu, S.-G.; Hsu, J.-Y.; Lin, P.-J.; Wu, W.J.;Peng, S.-M.; Lee,G.-H.; Wen, Y . 3 . Organometallics 1994,13,1699. (11)Horwitz, C. P.; Schriver, D. F. Adu. Organomet. Chem. 1984, 23,219.
complex containing both the terminal and bridging azides. Complex 4 has also a long dative Ru-Ru bond of 3.020(1) A,but it has only one apparently weak Ru(2)-C(2) bridge (Ru(2)-C(2) = 2.071(9) A;Ru(l)-C(2) = 1.981(9) A; Ru(l)-C(l) = 1.855(11) A; Ru(2)-C(3) = 1.844(10) A; Ru(l)-N(l) = 2.167(8) A; Ru(2)-N(l) = 2.181(7) Ru(2)-N(4) = 2.166(9) By comparison of the Ru-C bridging bond distances in 4 with those in 3, it is evident that the “weak”Ru(2)-C(2) bond in 4 is significantly shorter than the “weak” Ru(l)-C(l) bond in 3. Thus, from the fact that 4 does not react at all with PMe3, P(OMe)3, or PPh3 under the forcing conditions, even though 4 has a more open terminal site around one Ru center to potentially accept an incoming nucleophile than does 3 (LC(l)-Ru(l)-N(l) = 173.0(4)”in 4 versus LC(3)-Ru(2)-1(2) = 155.2(4)”in 31, a successful adduct formation of the doubly bridged Aframe complexes such as 3 and 4 with the added molecules appears to involve a switch from a bridging to a terminal group rather than the cleavage of the long dative Ru-Ru bond after an initial terminal attachment of the molecules at the open site. If such a switch would be blocked either thermodynamically or kinetically, no isolable adduct would form. In this regard, the facile conversion from a bridging to a terminal iodide in 3 helps formation of 8 and 9, but the stubborn carbonyl and azide bridges in 4 inhibit any PR3-adduct formation.
A;
A).
(12)(a) Vicente, R.; Escuer, A.; Ribas, J.; Solans, X. Inorg. Chem. 1992,31, 1726. (b) Escuer, A.;Vicente, R.; Ribas, J.; Fallash, M. S. E.; Solans, X.; Font-Bardia, M. Inorg. Chem. 1993,32,3727.(c) Cortes, R.; Pizzaro, J. L.; Lezama, L.; Arriortua, M. I.; Rojo, T. Inorg. Chem. 1994,33,2697.
1736 Organometallics, Vol. 14,No.4, 1995
Shiu et al.
Table 3. Atomic Coordinates ( x 104) and Equivalent Isotropic Displacement Coefficients" (A2x 103) for 4 4576( 1) 5680(1) 5352(1) 6486( 1) 3803(1) 4863(1) 3489(4) 4786(4) 6234(5) 5302(4) 5444(5)
5559(9) 6365(4) 6767(5) 7160(6) 6225(5) 4226(5) 3909(5) 4947(5) 601 l(6) 5115(3) 5224 5683 6033 5924 5465 5155(4) 4916 465 1 4624 4863 5128 7250(4) 7434 7089 6560
6376 672 1 7536(5) 8149 8528 8296 7683 7303 2533(4) 1997 2014 2567 3103 3085 3086(4) 2775 2768 3073 3384 3390 3784(4) 3368 3506 4060 4475 4337 5411(4) 5718 5829 5632 5325 5215 7275(6) 6267 6740
532(1) -887(1) 1602(2) 186(2) -311(2) - 1867(2) 1108(5) -816(4) -2386(6) 236(5) 463(6) 693(11) -1157(6) -1776(6) -2334(7) 1368(6) -1211(7) 890(7) -509(6) - 1810(7) 1238(4) 1335 1989 2545 2448 1794 2834(5) 3641 4330 4212 3404 2715 718(5) 712 149 -410
-405 159 763(5) 623 - 167 -818 -678 112 - 1203(5) - 1667 - 1824 -1518 -1055 -897 1194(5) 1780 1560 754 268 388 -3079(5) -3672 -3840 -3415 -2822 -2654 -3486(5) -4054 -3738 -2855 -2287 -2603 2396(9) 3542 2722
4256 3852 2211(6) 1950 2114 2539 2799 2636 1538(3) 1778 2466 2915 2675 1987 1185(3) 688 10 -172 325 1003 1827(3) 2137 2826 3207 2897 2207 1393(4) 96 1 328 126 558
1192 95( 11) 157 690
['Equivalent isotropic U,defined as one-third of the trace of the orthogonalized Ug tensor.
In order to get some other information about the paucity of reactivity of 4 toward PR3, a parallel reaction of 2 with another pseudohalide, Pz'-, obtained in situ from deprotonation of HPz' with Et3N, was also carried out. Unfortunately, this experiment did not give us any directly related information but did result in something unexpected. The reaction was found t o be complicated with at least two different products, as indicated by two triplet signals at -10.31 and -10.55 ppm in a lH NMR spectrum of the reaction mixture dissolved in CDzClz. Unlike 4, one product 10,separated cleanly from the mixture, does not contain two but one pseudohalide (i.e. Pz'-) and one hydride. The crystal structure of [Ruz(C0)30L-Pz')(H)01-DPPM)21(10)was determined (Figure 3) to have structural features similar t o those of 3 and 4, except for a much shorter Ru-Ru distance of 2.891(3)A and two more unsymmetrical bridging ligands (Ru(l)-N(l) = 2.260(18) A; Ru(2)-N(2) = 1.993(17) A; Ru(l)-C(2) = 1.742(25) A; Ru(2)-C(2) = 2.612(27) A). Carbonyl C(2)0(2)can even be classified as a semibridging carbonyl with an asymmetry parameter, Q,ll of 2.15 and appears to form a stronger bonding with Ru(1)than with Ru(2). Although the terminal hydride position in 10 could not be located from the last difference Fourier map, its position can be inferred to be connected to Ru(21, since the vacancy around this atom is larger than that around Ru(1). The hydride location is probably included in one mirror plane of 10 and is cis to the Pz' nitrogen atom N(2), the carbonyl C(3)0(3), and two equivalent phosphorus atoms P(2) and P(4)while being trans to C(2)0(2),as is supported by the presence of a triplet signal at -10.31 ppm ( 2 J p , = ~ 19 Hz) in the lH
NMR spectrum.13 The relatively long distance of 2.612(27) A between Ru(2) and C(2) compared to that of 1.742(25)between C(2) and Ru(1) is compatible with the high trans influence of the hydride ligand in 10.14 Alternatively speaking, carbonyl C(2)0(2)in a semibridging structure with LRu(l)-C(2)-0(2) = 151.4(22)" in 10 rather than a symmetrical or nearly symmetrical bridging structure like that found in 3 or 4 may act as a better n-acceptor with the R* orbital of CO tipped toward Ru(2) to dissipate effectively the accumulated charge density on this atom,15when a superior a-donor (Le. hydride) is at this atom and is trans to C(2)0(2) (Scheme 2).
Conclusions The cationic single-bridged A-frame complex 2 is a convenient starting material to form different types of double-bridged A-frame products 3, 4, and 10. The specific type of product appears to be dependent on the substrate used. The different reactivities of 3 and 4 toward phosphine ligands and the spectral evidence of the resulting phosphine adducts 8 and 9 reflect apparently the greater importance of a facile switch from a bridging to a terminal group relative to the cleavage of the dative Ru-Ru bond in a double-bridged A-frame (13)Schreiner, S.;Gallaher, T. N.; Parsons, H. F. Znorg. Chem. 1994, 33, 3021.
(14)Douglas, B. E.;McDaniel, D. H.; Alexander, J. J. Concepts and Models of Inorganic Chemistry, 3rd ed.; Wiley: New York, 1994; p 525. (15)Cotton, F . A. Prog. Inorg. Chem. 1976,21, 1.
An
Ru$ Diphosphine- a n d Acetate-Bridged Species
Organometallics, Vol. 14, No. 4, 1995 1737
Table 4. Atomic Coordinates ( x 104) and Equivalent Isotropic Displacement Coefficients" (biz x 103) for 10 155l(2) 1178(2) 4591(9) 5615(8) 451(5) - 12(6) 2926(6) 2617(5) 2552(13) 2318(5) 260( 18) 3566( 16) 3622(18) 3256( 19) 3530( 19) 2931( 18) 2834(18) 5705(26) 1403(17) - 169(15) -307( 13) 1515(22) 529(21) 267( 19) 1309(13) 1649 1566 1143 803 886 - 1556(13) -2421 -2641 - 1996 -1132 -912
1651( 1) 2737(1) 7683(8) 6433(7) 2537(4) 360 l(4) 943(4) 2129(4) 2855(12) 3348( 11) 3643(13) 1684(14) 2891(15) 3266( 16) 4058( 15) 4063( 15) 4 7 4 3 14) 7387(23) 139(12) 942( 11) 2163(11) 769(18) 1349(17) 2370(16) 2181(8) 2339 3181 3865 3708 2866 2726(8) 2372 1477 934 1287 2183
1682(1) 840( 1) 122l(3) 1792(3) 2193(2) 13lO(2) 1234(2) 393(2) 1628(6) 1235(6) 192l(7) 781(6) 2294(8) 1856(8) 1597(8) 12lO(7) 831(7) 1450(11) 2358(6) 1156(5) 157(5) 2100(9) 1267(9) 426(8) 3027(5) 3505 3695 3408 2931 2741 2649(5) 2832 2779 2543 2360 2413
572(12) 689 302 -203 -319 68 - 1876(14) -2933 -3530 -3069 -201 1 -1415 4854( 14) 5704 5629 4705 3855 3930 3433( 10) 3216 2339 1678 1895 2773 4507(12) 4948 4326 3265 2824 3445 3322( 10) 3191 2340 1619 1750 2602
5 4 2 3 10) 6267 6455 5801 4959 477 1 2730( 10) 2599 3229 3990 4121 349 1 1114(9) 82 1 60 -409 -116 645
-430( 10) -1249 -1712 -1357 -539 -75 3 114(10) 3762 4266 4123 3475 297 1 11 19(10) 406 - 148 12 725 1279
1424(4) 1238 770 487 673 1141 1162(5) 1166 1371 1572 1568 1363 1589(5) 1889 2160 2131 1831 1561 617(5) 406 503 812 1023 926 990) -166 -494 -557 -292 36 -379(5) -692 -682 -359 -47 -57
Equivalent isotropic U,defined as one-third of the trace of the orthogonalized Uv tensor.
3.56. 31P{1H} NMR (25 "C, acetone-ddCHzClz (l/l), 162 MHz): 6 14.79 (m, 2 P), 28.15 (m, 2 P). IR (CHZC12): vco 1982 m, 1912 s, 1712 m cm-'. Synthesis of [RU~(C~)~OI-CO)(C~-N~)(N~)(~~-DPPM (4). The orange-yellow compound 4 was prepared in a yield of 70% by a procedure similar to that for 3. Anal. Calcd for Experimental Section C&&&~P~RUZ: C, 55.88; H, 3.90; N, 7.37. Found: C, 55.70; H, 4.10; N, 7.48. 31P{1H}NMR (25 "C, CDC13, 162 MHz): 6 General Comments. All solvents were dried and purified by standard methods (ethers, paraffins, and arenes from 20.15-23.16 (m, 4 P). IR (CHZClz): vco 1960 m, 1914 s, 1696 potassium with benzophenone as indicator; halocarbons and m cm-l. acetonitrile from CaHz and alcohols from the corresponding Synthesis of [RU~(CO)~I~(PRS)(~~-DPPM)~I (R= Me (8), alkoxide) and were freshly distilled under nitrogen immediOMe (9)). To an orange-red suspension of 2 (153 mg, 0.117 ately before use. All reactions and manipulations were carried mmol) in THF (25 mL) was added PMe3 (0.5 mL, 1.0 M in out in standard Schlenkware, connected to a switchable double THF). The mixture was stirred for 10 min at ambient manifold providing vacuum and nitrogen. Reagents were used temperature, and some orange-yellow precipitate formed. This as supplied by Aldrich. 'H and 31P NMR spectra were mixture was then heated under reflux for 3 h to give a measured on a Bruker AMC-400 or a Varian Unity Plus-400 complete conversion. The precipitate formed was collected by ('H, 400 MHz; 31P,162 MHz) NMR spectrometer. 'H chemical filtration, washed three times with 15 mL of EtzO, and shifts (6 in ppm, J in Hz) are defined as positive downfield vacuum-dried. Recrystallization from CHZC12/MeOH gave the relative to internal MeSt (TMS) or the deuterated solvent, pure product 8 (81 mg, 50%). Anal. Calcd for C56H531203P5while 31P chemical shifts are defined as positive downfield Ruz: C, 48.57; H, 3.86. Found: C, 48.35; H, 3.86. 31P{1H} relative to external 85% H3P04. The IR spectra, calibrated NMR (25 "C, aCetOne-ds, 162 MHz): 6 -15.80 (m, 1PI, 22.06 with polystyrene, were recorded on a Hitachi Model 270-30 (m, 2 P), 30.28 (m, 2 P). IR (CHzClZ): vco 1946 sh, 1926 S, instrument. The following abbreviations are used: s, strong; 1742 m cm-1. Compound 9 was obtained similarly in a yield m, medium; w, weak. Microanalyses were carried out by the of 48%. Anal. Calcd for C ~ ~ H ~ ~ I Z O ~ P ~ R U C,Z47.82; . E ~ ZH, O: staff of the Microanalytical Service of the Department of 4.21. Found: C, 47.60; H, 4.04. 31P{1H} NMR (25 "C, Chemistry, National Cheng Kung University. aCetOneHd6, 162 MHz): 6 -28.33 (m, 2 P), 38.12 (m, 2 P), 96.70 Synthesis of [RU~(CO)Z(~~-CO)OI-I)-OI-DPPM)~] (3). A (m, 1P). IR (CHzClZ: YCO 1984 m, 1908 s, 1826 m cm-'. The suspension of [Ru~(CO)~(~-OZCM~)~-DPPM)ZI[BF~I (2;7157 presence of diethyl ether solvate was confirmed by 'H NMR mg, 0.128 mmol) and NaI (48 mg, 0.32 mmol) in MeOH (25 spectroscopy. mL) was heated under reflux for 5 h, giving an orange-red Synthesis of [R~~(CO)~OI-PZ')H~-DPPM)~I (10).A susprecipitate, which was collected by filtration. Recrystallization pension of 2 (200 mg, 0.163 mmol), HPz' (20 mg, 0.208 mmol), from CHZC12/MeOH gave the pure product 3 (131 mg, 78%). and Et3N (0.5 mL) in MeOH (15 mL) was heated under reflux Anal. Calcd for C ~ ~ H ~ ~ I Z O ~C, P~ 48.64; R U ZH,: 3.58. Found: for 36 h, giving an yellow precipitate, which was collected by C, 48.45; H,
complexes to form isolable adducts. Further studies on the synthetic uses of 2-4, the hydride source, and isolation of the second hydride compound are currently in progress in our laboratory.
Shiu et al.
1738 Organometallics, Vol. 14,No. 4, 1995 Table 5. Crystal Data for 3, 4, and 10 compd formula fw diffractometer used spaw group a, A b, A c.
A
Z
Dcaicd, g Cm-? A(Mo K a ) , 8,
F(000) unit cell detn: no. 28 range, deg scan type 28 range, deg h,k,l range p(Mo Ka), cm-I cryst size, mm transmissn factor temp, K no. of measd rflns no. of unique rflns no. of obsd rtlns (No) R," R,"
GOF" refinement program no. of ref params (Np) weighting scheme g (2nd ext coeff) x 104 (ua)max
(Ae)max,
solvent
(AeLn, e 8,-'
3 CS~HJ~I~O~P~RW 1385.88 Nonius CAD4 monoclinic, P 2 1 k 12.779(4) 27.447( 1 1) 15.487(4) 95.676(23) 5405(3) 4 1.699 0.709 30 2713 24, 18-31 8-28 2-45 i 1 3 , 2 9 , 16 18.3 0.10 x 0.10 x 0.30 0.859- 1.000 298 7069 7069 3830 (>2a) 0.041.0.034 1.33 NRCVAX 623 [u2(Fo)1-I 0.314(11) 0.074 -3.6, 3.5 Et20
filtration. Recrystallization from CH2CldEt20 gave the pure product 4 (90mg, 48%). Anal. Calcd for C~~H~zN203P4Ruz: C,60.52;H, 4.55;N, 2.43. Found: C, 60.45;H, 4.56;N, 2.37. 31P{1H}NMR (25 "C, CD2C12, 162 MHz): 6 19.54 (m, 2 P), 33.45(m, 2 P). IR (CHzC12): YCO 1924 s, 1876 s, 1810 m cm-l. Single-Crystal X-ray Diffraction Studies of 3, 4, and 10. Suitable single crystals were grown from CHzClz/hexane or CH2Clfit20 at ambient temperature and chosed for the single-crystal structure determination. Atomic coordinates and equivalent isotropic displacement coefficients for 3,4, and 10 are listed in Tables 2-4, respectively. The X-ray diffraction data were measured on a four-circle diffractometer. Intensities of 3 standard reflections were monitored every 1 h or every 500 reflections throughout the data measurement. The variation was less than 2% for 3,5% for 4, and 12% for 10. For 3, the structure was solved by the heavy-atom method and refined by a full-matrix least-squares procedure using NRCVAX.16 For 4 and 10, the structure was solved by direct methods and refined by a full-matrix least-squares procedure using SHELXTL-PLUS." Two chlorine atoms and one carbon (16)Gabe, E. J.; Le Page, Y.; Charland, J.-P.; Lee, F. L.; White, P. S. J.Appl. Crystallogr. 1989,22, 384.
4
10
CS~HM,C~&JN"RU~ 1223.89 Siemens P4 monoclinic, P2Jn 19.764(2) 14.647(2) 20.033(2) 97.532(8) 5749( 1) 4 1.414 0.710 73 2519 25, 10-13 8-0 4-50 24, 18, i 2 4 7.75 0.4 x 0.4 x 0.5 0.421-0.491 298 10968 10197 6067 ( > 4a) 0.058, 0.086 1.16 SHELXTL-PLUS 536 [a2(Fo) 0.003F2]-1 0 0.001 -0.7, 1.3 CHzCl2
CS~HS~C~ZNZO?PJRU~ 1235.91 Siemens P4 monoclinic, P211c l3.O46(2) 15.179(3) 28.226(5) 95.93( 1) 5559(1) 4 1.468 0.710 73 2480 25, 10-13 8-0 4-45 15, 17, f 3 1 8.0 0.1 x 0.2 x 0.4 0.865-0.939 298 806 1 7320 2608 ( > 6a) 0.074, 0.081 1.70 SHELXTL-PLUS 258 [02(Fo) 0.005F02]-1 0 0.001 -1.3, 0.9 CHzCl2
+
+
atom of the CHzClz solvate in 4 were located from difference Fourier maps, and this solvent molecule was refined as a rigid group using the SHELXTL command DFM 6. Hydrogen positions, except those of Pz'- and H- of 10, were either located from the difference maps or calculated at idealized locations. The other essential details of the single-crystal data measurements and refinements are given in Table 5.
Acknowledgment is made to the National Science Council of the Republic of China for financial support of this research (Contract No. NSC84-2113-M006010). Supplementary Material Available: Tables of all bond lengths and angles, anisotropic displacement coefficients, and hydrogen coordinates for 3, 4, and 10 (14pages). Ordering information is given on any current masthead page.
OM9407013 (17)Siemens Analytical X-ray Instruments Inc., Karlsruhe, Germany, 1991.
