Organometallics 1995, 14,3952-3957
3952
Agostic B-H-Ru Bonds in exo-Monophosphino-7,8-dicarba-nido-undecaborate Derivatives Clara Vifias,' Rosario Nufiez,' Miquel A. Flores,t Francesc Teixidor,*lt Raikko Kivekas,$ and Reijo Sillanpaag Institut de Cikncia de Materials de Barcelona, Campus de Bellaterra, Cerdanyola, 08193 Barcelona, Spain, Inorganic Chemistry Laboratory, Box 6, University of Helsinki, FIN-00024 Helsinki, Finland, and Chemistry Department, University of Turku, FIN-20500 Turku, Finland Received January 3, 1995@ The reaction of [ N M ~ ~ I [ ~ - P P ~ Z - ~ - M ~ - with ~ , ~ RuClyH20 - C ~ B ~ Hor~ RuC12(DMS0)4 OI leads Each carborane ligand is tridentate, to the formation of [Ru(7-PPhz-8-Me-7,8-C2BgHlo)21. forming one P-Ru bond and two B-H-Ru agostic bonds. The number of isomers obtained depends on the initial ruthenium form, giving one isomer (1)when RuClyH20 is used and two isomers (1 and 2) in the case of the DMSO derivative. No reaction is found with similar ~-= C ZPh,Me), B ~ H ~suggesting O~ that the thiocarborane ligands [ N M ~ ~ I [ ~ - S R - ~ - M ~ - ~ , (R surrounding Pz(BH)4 is a better stabilizing system. The complexes have been characterized by a n X-ray diffraction study. Introduction
The chemistry of ruthenium and its complexes plays an important role in fields such as catalysis1 of organic reactions or, more recently, in the search for organic conductors2to be used as elements in electronic circuits. In such applications, stable, long-lasting molecules are demanded along with the desired specific properties. Phosphorus-, nitrogen-, or sulfur-containing ligands are usually involved in those complexes in order to fulfill these requirements. Since the discovery of carboranes, boron chemistry has provided new, versatile clusters which can bind transition metals, giving stable complexes that are of interest in the aforementioned applications. Our research has been dealing with the chemistry of platinum-group metal complexes of 11 vertex exothiocarborane and exo-phosphinocarborane derivative^.^ Besides the sulfur-metal and phosphorus-metal interaction, agostic B-H-M bonds have been found. In order to further explore the coordinating properties of
' Institut de Cikncia de Materials de Barcelona, CSIC.
University of Helsinki. University of Turku. @Abstractpublished in Advance ACS Abstracts, July 1, 1995. (1)For recent applications see: (a) Darensbourg, D. J.; Joo, M.; Kannisto, M.; Katho, A,; Reibenspies, J. H.; Daigle, J. Inorg. Chem. 1994,33,200 and references therein. (b) Gargulak, J. D.; Gladfelter, W. L. Inorg. Chem. 1994,33,253. (2) (a)Sano, M.; Taube, H. Inorg. Chem. 1994,33,103 and references therein. (b) Sun, Y.; DeArmond, K. Inorg. Chem. 1994,33,2004.(c) Meyer, T. J.;Meyer, G. J.; Pfennig, B. W.; Schoonover,J. R.; Timpson, C. J.; Wall, J. F.; Kobusch, C.; Chen, X.; Peek, B. M.; Wall, C. G.; Ou, W.; Erickson, B. W.; Bignozzi, C. A. Znorg. Chem. 1994,33,3952. ( 3 ) (a)Teixidor, F.; Rudolph, R. W. J . Organomet. Chem. 1983,241, 301. (b) Vifias, C.; Butler, W. M.; Teixidor, F.; Rudolph, R. W. Organometallics 1984,3,503.(c) Vifias, C.; Butler, W. M.; Teixidor, F.; Rudolph, R. W. Inorg. Chem. 1986,25,4369.(d)Teixidor, F.; Rius, J.; Romerosa, A. M.; Miravitlles, C.; Escriche, Ll.; Sanchez, E.; ViAas, C.; Casabo, J. Inorg. Chim. Acta 1990, 176, 287. (e) Teixidor, F.; Romerosa, A. M.; Rius, J.; Miravitlles, C.; Casab6, J.; Viiias, C.; Sanchez, E. J . Chem. Soc., Dalton Trans. 1990,525.(0 Teixidor, F.; Vifias, C.; Rius, J.;Miravitlles, C.; Casab6, J. Inorg. Chem. 1990,29, 149.(gJTeixidor, F.; Casabo, J.; Romerosa, A. M.; Vifias, C.; Rius, J.; Miravitlles, C. J . Am. Chem. SOC.1991,113,9895. t
5
those B-H groups and study their dependence on the electron-rich element attached to the carborane cage, new metal complexes have been synthesized. In this paper we report the synthesis and structural characterization of two isomers of the first ruthenium carborane complex incorporating four B-H-Ru agostic bonds, which are provided by two nido-monophosphinocarborane anionic ligands. Results and Discussion
Monothioethers of the type indicated in Figure 1A have been proven to be tridentate4 when they are bonded to Ru(II), which is a transition-metal ion that demands an octahedral geometry. The coordination takes place by means of the thioether group and boron atoms B(2) and B(11) through B-H-Ru agostic bonds. The 3-fold denticity of these compounds parallels that of dithioether species of a similar type indicated in Figure 1B. In that case coordination takes place via the two sulfur atoms and the B(3)-H-Ru agostic bond. Consequently the existence of one or two sulfur elements in the molecule does not modify the binding capacity of these exo-thioether 7,8-dicarba-nido-undecaborate derivatives, but it does modify the nature and number of the participating B-H groups. A further difference between mono- and dithioethers has been found upon their coordination to the moiety [RuWl(PPh&]+. The monothioether alters the cage by removal of B(5), while the dithioethers leave the cage ~naltered.~ The monothioether species offer the possibility of being separated into enantiomers and consequently being used as tricoordinating4 (S, BH(21, BH(11)), or dicoordinatine (S, BH(11)) anionic chiral ligands in (4)Teixidor, F.; ViAas, C.; Casab6, J.; Romerosa, A. M.; Rius, J.; Miravitlles, C. Organometallics 1994,13,914. (5)Teixidor, F.; Ayllbn, J. A,;Viiias, C.; Kivekas, R.; Sillampaa, R.; Casabo, J. Organometallics 1994,12,2751. (GJTeixidor, F.; Viiias, C.; Flores, M. A. To be submitted for publication.
0276-733319512314-3952$09.00/0 0 1995 American Chemical Society
Agostic B-H-Ru
Bonds in Carborane Derivatives A
A B Figure 1. Schematic drawings of mono- and dithioether derivatives of 7,8-dicarba-nido-undecaborate.
Organometallics, Vol. 14, No. 8, 1995 3953 r)
rr)
m)
Iv)
I I
I
I
Figure 2. Schematic drawing of the 7-(diphenylphosphino)-8-methyl-7,8-dicarba-nido-undecaborate anion showing the A motif.
Me asymmetric catalysis. Due to the role phosphines play in catalysis, the arylphosphine equivalent to Figure 1A was synthesized (Figure 2). This would lead to a comparison of the coordinating capacity of the monothioethers versus monophosphine derivatives. The C-P bond in exo-phosphino-1,2-dicarba-closo-dodecaborane derivatives easily breaks in the partial degradation Figure 3. Isomers compatible with the formulation [Ruprocess; however, a procedure has been found which (7-PPhz-8-Me-7,8-C2BsHlo)2].The bonding scheme shown enables the synthesis of the ligands in the free state.7 at the bottom has been used. A stands for an anticlockwise The reaction of [7-PPh2-8-Me-7,8-C2BgH101-, abbreviand C for a clockwise motif following Figure 2. ated as Lpn-, with RuClsxHzO in a 2:l ratio in ethanol produced a very low yield of yellow crystals with the the starting nido-carborane had been converted upon stoichiometry Ru(Lp,-,)z (1). The low yield was attributed Ru complexation into an arachno species by the removal to the partial consumption of the phosphine ligand to of B(5). This nido to arachno conversion could have produce the Ru(II1) Ru(I1) conversion. The lH NMR taken place with the monophosphines as well; however, spectra displays broad signals at -11.20 and -10.32 the llB NMR indicates the 11-vertex cage retention. ppm, which are assigned to two sorts of B-H-Ru Even more conclusive than the llB NMR spectrum is agostic bonds. Furthermore, the existence of a unique the lack of a quartet of doublets at --2.40 ppm, which CH3 peak at 1.51 ppm indicated that the two cages were we have found indicative of two B-H-B hydrogen symmetry-related, No other -CH3 peaks were obbridges in the open face defined by five boron atoms in served, which proved the isomeric purity of the crystal(5)-C& cages. line material. The 31P NMR also displayed only one The low yield obtained in the former synthesis of (1) signal at 22.93 ppm, in agreement with the sample’s using RuClsxHzO was partially overcome by using isomeric purity. [RuC12(DMS0)41 as a source of Ru(I1). The reaction is The 2:1, Lp,-:Ru(II), stoichiometry and the hexacoindicated in eq 1. ordinating predisposition of Ru(I1) presumes that each Lp,- ligand has to be tricoordinating. This was expected 2[Lp,][RuCl&DMSO)J [Ru(Lpn)21 (1) in the event Lpn- had a coordinating behavior compa1 : l or 2 : l 192 The three rable to that of [7-SR-8-Me-7,8-CzBgHlol-. The product of this reaction and that formerly obcoordinating sites could be provided by the -PPh2 tained with RuClsxHzO show a common [Ru(Lpn)21 moiety and BH(11) and BH(2) fragments. Thus, as with stoichiometry, but the lH NMR of the [RuCldDMS0)41 the monothioether, the activation of two BH units had reaction mixture displayed two peaks of unequal intenbeen made possible in this monophosphinocarborane sity in the -CH3 region at 1.51 and 1.23 ppm. The first derivative. peak corresponded to the signal found in 1 following the Earlier we did report4 that the reaction of [7-SR-8RuCl3 procedure, but the peak a t 1.23 ppm should Me-7,8-CzBgHloI- with [RuC12(PPh3)31yielded the compound [RuCl{~ - S R - ~ - M ~ - ( ~ ) - ~ , ~ - C ~ where B ~ H I O }correspond ( P P ~ ~ Mto,a new isomer. Consequently, the [RuC12(DMS0)4] method has produced two isomers, which are 1 and 2. The 31PNMR also shows two resonances at (7) Teixidor, F.; ViAas, C.; Abad, M. M.; NuAez, R.; Kivekas, R.; 22.93 and 36.53 ppm, the first corresponding to 1. The Sillanpaa, R. J . Organomet. Chem., submitted for publication.
-
+
-C
Viiias et al.
3954 Organometallics, Vol. 14,No. 8, 1995 C42
a
Table 1. Final Positional Parameters and Isotropic Thermal Parameters (A2)with Esd's in Parentheses for [Ru(7-PPhz-8-Me-7,8-CzBsHlo)21*2(Me)zCO (1) Ru
c52
P(1)
c21
c22
63
Figure 4. Simplified ORTEP view of [Ru(7-PPh+Me7,8-C~BgH~o)z1.2(Me)~CO (1) showing 30% thermal ellipsoids.
Q
c1
C16
Cl5
Figure 5. Simplified ORTEP view of LRu(7-PPhz-8-Me7,8-CzBgHlo)z1.1.486CHC13 (2) showing 30% thermal ellipsoids.
lH NMR in the negative area shows, in addition to the signals at resonances assigned to 1, two B-H-Ru -5.55 and -10.70 ppm, which are attributed to the 2 isomer. There are several isomers compatible with this stoichiometry, which are the result of the PPh2, BH(21, and BH(11) disposition of one cluster when the second one is kept immobile around the Ru(I1). In Figure 3 the possible isomers are represented. To make the representation clearer, only the intervening atoms are depicted. The structure of the ligating section is shown at the bottom of Figure 3. In the event the isomer is optically active, only one of the enantiomers is represented. This is the general situation, since optical isomers should be expected for I-V but not for VI in Figure 3. The capital letters C and A in the drawing stand for clockwise and anticlockwise motifs. To distinguish these, the CIP protocol has been used, in a view of the cluster through a n axis moving down to the unique vertex as shown in Figure 2.
B(1) B(2) B(3) B(4) B(5) B(6) C(7) C(8) B(9) B(10) B(11) C(12) (313) C(14) C(15) C(16) C(17) C(18) C(19) C(20) C(21) C(22) C(23) C(24) P(2) B(31) B(32) B(33) B(34) B(35) B(36) C(37) C(38) B(39) B(40) B(41) C(42) C(43) C(44) C(45) C(46) (347) (348) C(49) C(50) C(51) C(52) C(53) C(54) O(55) C(56) C(57) C(58) O(59) C(60) C(61) C(62)
xla 0.96172(9) 1.0811(3) 0.734(1) 0.848(1) 0.867(1) 0.802(1) 0.746(1) 0.770(1) 0.9709(9) 0.9459(9) 0.882(1) 0.856(1) 0.917(1) 1.034(3) 1.1011(9) 1.023(1) 1.028(1) 1.112(1) 1.194(1) 1.190(1) 1.2152(9) 1.318(1) 1.418(1) 1.425(1) 1.328(1) 1.2240(9) 0.8438(3) 1.082(1) . 1.014(1) 0.944(1) 1.048(1) 1.185(1) 1.162(1) 0.9540(9) 0.971(1) 1.107(1) 1.185(1)
1.072(1) 0.873(2) 0.8317(9) 0.908(1) 0.898(1) 0.812(1) 0.738(1) 0.746(1) 0.7027(9) 0.636(1) 0.529(1) 0.489(1) 0.555(1) 0.6597(9) 1.426(1) 1.354(1) 1.248(1) 1.391(1) 0.602(2) 0.548(2) 0.613(3) 0.420(2)
Ylb
zic
0.3078(1) 0.2092(4) 0.241(1) 0.259(1) 0.151(2) 0.237(2) 0.394(2) 0.402(2) 0.271(1) 0.254(1) 0.394(2) 0.504(2) 0.406(1) 0.180(3) 0.028(1) -0.060(1) -0.200(1) -0.256(1) -0.177(1) -0.032(1) 0.287(1) 0.254(1) 0.315(2) 0.415(1) 0.450(1) 0.387(1) 0.4146(3) 0.136(1) 0.218(2) 0.211(2) 0.235(2) 0.262(1) 0.243(2) 0.366(1) 0.375(1) 0.409(2) 0.411(2) 0.376(1) 0.431(4) 0.601(1) 0.678(1) 0.821(1) 0.884(1) 0.806(1) 0.665(1) 0.353(1) 0.418(1) 0.363(1) 0.244(1) 0.179(1) 0.236(1) 0.873(1) 0.797(2) 0.823(2) 0.647(2) -0.178(2) -0.173(3) -0.178(5) -0.160(5)
0.63494(2) 0.59588(7) 0.5600(3) 0.5890(3) 0.5559(3) 0.5229(3) 0.5361(3) 0.5778(3) 0.5675(2) 0.5306(2) 0.5176(3) 0.5519(3) 0.5836(3) 0.5103(7) 0.5928(2) 0.6072(3) 0.6045(3) 0.5864(3) 0.5725(3) 0.5751(3) 0.5860(2) 0.6031(3) 0.5956(3) 0.5720(3) 0.5554(3) 0.5623(3) 0.67264(7) 0.7195(3) 0.6863(3) 0.7225(3) 0.7528(3) 0.7354(3) 0.6931(3) 0.7017(2) 0.7386(2) 0.7472(3) 0.7099(3) 0.6813(3) 0.7588(8) 0.6739(2) 0.6912(3) 0.6907(3) 0.6738(3) 0.6571(3) 0.6568(3) 0.6822(2) 0.7046(3) 0.7120(3) 0.6973(3) 0.6746(3) 0.6676(3) 0.6467(3) 0.6531(4) 0.6692(4) 0.6425(3) 0.5638(4) 0.5371(4) 0.5064(4) 0.5360(7)
Ueg" 0.0376(3) 0.042(1) 0.049(6) 0.047(6) 0.057(7) 0.064(7) 0.061(7) 0.053(6) 0.040(5)
0.048(5) 0.056(6) 0.058(6) 0.036(5) 0.065(4) 0.045(5) 0.057(5) 0.069(6) 0.076(6) 0.067(5) 0.062(6) 0.041(4) 0.061(6) 0.081(6) 0.074(6) 0.066(6) 0.051(5) 0.040(1) 0.038(5) 0.042(6) 0.056(6) 0.052(6) 0.053(6) 0.049(6) 0.037(4) 0.047(5) 0.057(7) 0.057(6) 0.035(5) 0.063(4) 0.038(5) 0.065(5) 0.072(6) 0.066(6) 0.073(6) 0.062(5) 0.037(4) 0.059(5) 0.069(6) 0.065(6) 0.060(5) 0.049(5) 0.193(6) 0.132(6) 0.119(6) 0.111(6) 0.340(8) 0.340(8) 0.340(8) 0.340(8)
U,,= 1i3~,~JU~ar*aJ*a,.aJ. To unambiguously know the nature of compounds 1 and 2, their X-ray analysis was necessary. Crystals suitable for X-ray analysis were obtained from recrystallization. The isomer I1 in Figure 3 was obtained pure in the RuCls reaction, while a mixture of isomers I and I1 was obtained by using [RuClz(DMSO)41. In the second case, care was taken to examine a crystal not having the cell parameters of the former. Figure 4 shows the molecular structure of compound 1. Table 1 lists positional parameters, and Table 2 lists selected interatomic distances and angles. The Ru(I1) a
Agostic B-H-Ru
Table 2. Selected Interatomic Distances (A) and Angles (deg) with Esd's in Parentheses for
[Ru(7-PPh2-8-Me-7,8-C2B9H1&l-2(Me)2CO (1) Ru-P( 1) Ru-B(2) Ru-B(32) Ru-H(2) RU-H(32) P(1)-C(7) P(1)- C(19) P(2)-C(43) B(3)-C(7) C(7)-C(8) C(8)-B(9) B(9)-B(10) B(33)-C(37) C(37)-C(38) C(38)-B(39) B(39)-B(40) P(l)-Ru-P(2) H(2)-Ru-H(41) H(ll)-Ru-H(32) Ru-P(l)-C(7) Ru-P(l)-C(13) Ru-P( 1)-C( 19) C(7)-P(l)-C(13) C(7)-P(l)-C(19) C(131-P( 11- C(19) Ru-P(2)-C(37) Ru-P(2)-C(43) Ru-P(2)-C(49) C(37)-P(2)-C(43) C(37)-P(2)-C(49) C(43)-P(2)-C(49) C(7)-B(3)-C(8) P(l)-C(7)-B(2) P(l)-C(7)-B(3) P(l)-C(7)-C(8) P(l)-C(7)-B(ll)
Organometallics, Vol. 14, No. 8, 1995 3955
Bonds in Carborane Derivatives
2.373(3) 2.34(1) 2.38(1) 1.88 1.94 1.82(1) 1.80(1) 1.82(1) 1.74(2) 1.56(1) 1.64(2) 1.81(2) 1.75(2) 1.55(1) 1.65(2) 1.82(2) 177.6(1) 172 173 83.8(4) 122.0(4) 121.0(4) 111.7(5) 108.4(5) 106.7(5) 84.9(4) 120.5(4) 123.3(4) 107.3(5) 113.6(5) 104.8(5) 53.3(6) 103.0(7) 115.6(8) 135.4(8) 106.1(7)
Ru-P(2 ) Ru-B(11) Ru-B(41) Ru- H(11) Ru- H(41) P(l)-C(13) P(2)-C(37) P(2)-C(49) B(3)-C(8) C(7)-B(ll) C(8)-C(12) B(lO)-B(ll) B(33)-C(38) C(37)-B(41) C(38)-C(42) B(40)-B(41) C(8)-C(7)-B(ll) C(7)-C(8)-B(9) C(7)-C(8)-C(12) B(9)-C(8)-C(12) C(8)-B(9)-B(10) B(9)-B(lO)-B(ll) C(7)-B(ll)-B(lO) C(37)-B(33)-C(38) P(2)-C(37)-B(32) P(2)-C(37)-B(33) P(2)-C(37)-C(38) P(2)-C(37)-B(41) C(38)-C(37)-B(41) C(37)-C(38)-B(39) C(38)-B(39)-B(40) C(37)-C(38)-C(42) B(39)-C(38)-C(42) B(39)-B(40)-B(41) C(37)-B(41)-B(40)
2.358(3) 2.39(1) 2.38(1) 1.95 1.93 1.79(1) 1.80(1) 1.81(1) 1.74(2) 1.62(2) 1.53(3) 1.76(2) 1.76(2) 1.64(2) 1.53(3) 1.79(2) 115.1(9) 108.0(9) 119(1) 121(1) 108.4(9) 102(1) 106.5(9) 52.2(7) 105.2(7) 120.3(7) 135.9(8) 103.1(7) 115.3(9) 108.6(9) 108.9(9) 119(1) 122(1) 100.6(9) 106.3(9)
cation is coordinated octahedrally to two tridentate carborane cages, and two acetone molecules from recrystallization occupy empty places in the lattice. The phosphorus atoms are in trans positions, and BH(2)'s and BH(l1)'s are in cis positions with the molecular symmetry C1. In the complex both clusters have the A configuration. The structure is the enantiomer to that of isomer I1 in Figure 3. However, as 1 crystallizes in a centrosymmetric space group, the crystal contains an equal amount of isomer I1 and its enantiomer with ligand configuration C. Figure 5 shows the complex unit of compound 2. Table 3 lists positional parameters, and Table 4 lists selected interatomic distances and angles. The molecular structure is essentially the same as for compound 1. The Ru(I1) cation is coordinated octahedrally t o two tridentate carborane cages, and chloroform molecules occupy empty places in the lattice. The phosphorus atoms are in positions cis t o each other, the BH(2)'s are trans to phosphorus atoms, and the BH(1l)'s are trans t o each other. The molecular symmetry is C2 with Ru on the 2-fold axis. In the complex both ligands have the C configuration and the structure is equivalent to that of isomer I in Figure 3. However, as 2 crystallizes in a centrosymmetric space group, the crystal contains an equal amount of isomer I and its enantiomer with ligand configuration A. A comparison of distances and angles of the two isomeric complex units reveals some significant differences. In 1 the Ru-P distances (2.373(3) and 2.358(3) A)are clearly longer than in 2 (2.298(2) A). The RuB(2) distance in 2 (2.436(8) A) is slightly longer than
Table 3. Final Positional Parameters and Isotropic Thermal Parameters (A)with Esd's in Parentheses for
[Ru(7-PPh~-8-Me-7,8-C~B~Hl~)21~l.48f3CHC13 (2) xla
Ru P B(1) B(2) B(3) B(4) B(5) B(6) C(7) C(8) B(9) B(10) B(11) C(12) C(13) C(14) C(15) C(16) C(17) (318) C(19) C(20) C(21) C(22) (323) C(24) Cl(lIb C1(2)* C1(3)b C(25)b
'12
0.5072(1) 0.5756(5) 0.5399(4) 0.5397(4) 0.6185(5) 0.6686(5) 0.6162(5) 0.5693(3) 0.6099(4) 0.6862(5) 0.6882(5) 0.6043(4) 0.6026(5) 0.5495(4) 0.5110(4) 0.5445(5) 0.6148(5) 0.6536(4) 0.6207(4) 0.4348(4) 0.4358(5) 0.3847(6) 0.3324(6) 0.3304(5) 0.3820(4) 0.6874(3) 0.6125(3) 0.7553(3) 0.6931(8)
Ylb 0.83192(7) 0.7112(2) 1.0473(7) 0.9449(7) 0.9152(7) 0.9670(8) 1.0260(8) 1.0166(7) 0.8126(6) 0.8237(6) 0.8813(8) 0.9192(9) 0.8653(7) 0.7304(8) 0.5707(6) 0.4700(7) 0.3634(7) 0.3572(6) 0.4572(7) 0.5630(6) 0.6941(6) 0.6135(8) 0.6127(9) 0.690(1) 0.7713(9) 0.7723(8) 0.6691(5) 0.8793(5) 0.8674(6) 0.827(2)
ZIC
Vega
0.3394(1) 0.4201(5) 0.3550(4) 0.4372(4) 0.4936(5) 0.4488(5) 0.3597(5) 0.3933(3) 0.4704(3) 0.4817(5) 0.3954(5) 0.3427(5) 0.5180(4) 0.3498(4) 0.3307(4) 0.3395(5) 0.3676(5) 0.3858(5) 0.3766(5) 0.3675(4) 0.4183(5) 0.4447(6) 0.4240(6) 0.3766(6) 0.3481(5) 0.7171(3) 0.6808(2) 0.7012(3) 0.7287(7)
0.0258(3) 0.0298(7) 0.042(4) 0.032(3) 0.034(3) 0.041(4) 0.045(4) 0.037(4) 0.031(3) 0.039(3) 0.047(4) 0.049(4) 0.036(4) 0.066(4) 0.035(3) 0.053(4) 0.065(4) 0.067(5) 0.062(4) 0.052(4) 0.039(3) 0.064(4) 0.095(7) 0.097(6) 0.077(5) 0.060(4) 0.153(3) 0.144(3) 0.172(4) 0.118(9)
'14
Ue, = l/~~,~JUUalhuJ*ul.aJ. * Site occupation parameter 0.743(4).
Table 4. Selected Interatomic Distances (A) and Angles (deg) with Esd's in Parentheses for [Ru(7-PPh2-8-Me-7,8-C2B9Hl~)21*1.488CHC13 (2) Ru-P Ru-B(l1) Ru- H( 11) P-C(13) B(2)-H(2) B(3)-C(8) C(7)-B(ll) C(8)-C(12) B(lO)-B(ll) P-Ru-H(2) P-Ru-H(l1) P-Ru-P" P-Ru-H(2)" P-Ru-H( 11)" H(2)-Ru-H(11) H(2)-Ru-H(2P H(2)-Ru-H(11P H( 11)-Ru- H( 11)" Ru-P-C(7) Ru-P-C(13) Ru- P- C(19) C(7)-P-C(13) C(7)-P-C(19)
2.298(2) 2.363(8) 1.69(4) 1.818(7) 1.23(6) 1.73(1) 1.60(1) 1.51(1) 1.80(1)
Ru-B(2) Ru-H(2) P-C(7) P-C(19) B(3)-C(7) C(7)-C(8) C(8)-B(9) B(9)-B( 10) B(ll)-H( 11)
84(2) 81(2) 105.33(8) 165(2) 92(2) 102(2) 89(3) 87(2) 169(2) 86.7(2) 121.8(3) 120.9(2) 107.4(3) 110.7(4)
Symmetry code: 1 - x , y ,
'12
C(13)-P-C(19) C(7)-B(3)-C(8) P-C(7)-B(2) P-C(7)-B(3) P-C(7)-C(8) P-C(7)-B(11) C(8)-C(7)-B(ll) C(7)-C(8)-B(9) C(7)-C(8)-C(12) B(9)-C(8)-C(12) C(8)-B(9)-B(10) B(9)-B(lO)-B(ll) C(7)-B(ll)-B(lO)
2.436(8) 2.01(7) 1.806(6) 1.805(9) 1.74(1) 1.538(9) 1.65(1) 1.88(2) 1.27(4) 106.5(4) 52.6(4) 103.1(4) 117.8(5) 135.4(6) 102.6(5) 117.3(6) 108.7(7) 119.3(6) 120.6(6) 107.7(6) 99.4(7) 106.7(6)
- 2.
the Ru-B(2) distance in 1 and Ru-B(11) distances in 1 and 2. In 1 the P-Ru-P angle value does not deviate much from linearity (177.6(1)"). In 2, in which the phosphorus atoms are in a cis disposition, the P-Ru-P angle (105.33(8)")is considerably opened compared to the ideal angle (90") of an octahedral coordination sphere. The opening is not unexpected, taking into account the great differences in the Ru-H and Ru-P bond lengths. The angles around the phosphorus atoms
3956 Organometallics, Vol. 14, No. 8, 1995
Viiias et al.
Synthesisof [ R ~ ( ~ - P P ~ ~ - ~ - M ~ - ~ (a) , ~To- 25 C~BBH~O) vary from 83.8(4)to 123.3(4)' for 1, and from 86.7(2) to cm3 of deoxygenated methanol containing 428 mg (1.06 mmol) 121.8(3)"for 2. In both structures the smallest values of [NMeJ[7-PPh2-8-Me-7,8-CzBgHl,l was added RuClszHnO are for Ru-P-C(7) angles (83.8(3)and 84.9(4)"for 1 and (48 mg, 0.197 mmol), and the mixture was refluxed for 6 h. A 86.7(2)" for 2), and the values are much smaller than red solid precipitated in the warm mixture. The solution was the others, indicating angle strain at the phosphorus concentrated to one-third of the initial volume. The red solid atoms caused by tridentate coordination of the carbowas separated by filtering under nitrogen, and then it was rane cages. washed with deoxygenated methanol (10 cm3)and ethyl ether. Practically all the red solid dissolved in ethyl ether, forming By using monophosphinocarboranes as the unique a red solution. The solvent was eliminated to yield a n orangesource of Ru(I1) ligands, it has been possible to get the red solid, yield 15 mg (3%). FTIR (KBr): Y (cm-') 2551, 2530 RuP2(BH)4 motifs. To our knowledge, these molecules (B-H). 'H FT NMR (250 MHz, CDC13,25 "C, TMS): d -11.20 contain the largest number of BH units in the vicinity (br, 1, BHRu), -10.32 (4, 1, BHRu), -2.73 (br, 1, B-H-B), of a metal. Examples of molecules with a large number 1.51 (s, 3, CH3), 7.20-7.60 (m, 10, Cavl-H). IlB FT NMR (128 of BH units in the metal neighborhood are (OChMnMHz, CO(CD&, 25 "C, BF3.Et20): d 6.01 (d, 'J(B,H) = 142 B8H13,8 (OC)3MnB3Hs? ( P P ~ ~ ) ~ C ~ R U ( C ~ Band ~ H ~ O RHz, Z )lB), , ~-10.33 ~ (lB), -15.37 ( l B ) , -17.05 (d, 'J(B,H) = 141 C P Z ~ ( C H ~ ) ~ ( C B all ~ ~ containing H I ~ ) , ~ ~three BH units Hz, lB), -22.93 (d, 'J(B,H) = 91 Hz, lB), -23.49 (d, 'J(B,H) attached to the metal. The low bonding capacity of the = 122 Hz, lB), -28.59 (2B), -38.76 (d, 'J(B,H) = 141 Hz, 1B). BH groups is proved by the instability of some of those 31P{1H}FT NMR (101 MHz, CDC13, 25 "C, H3P04, 85%): d 22.93 (s). Anal. Calcd for C ~ O H ~ ~ B ~ C, ~ P47.00; ~ R UH,: 6.07. compounds. In contrast, 1 and 2 are fairly stable in the Found: C, 46.95; H, 6.03. From slow evaporation of an ethyl solid state as well as in solution. To have a comparison etheracetone (5:l) solution of the solid, red microcrystals were with the equivalent monothioethers, reactions similar obtained. to those described above leading to 1 and 2 have been (b) To 20 cm3 of deoxygenated ethanol containing 100 mg conducted. In contrast, the reactions of [('l-SPh-B-Mewas ~ -added ~,~-C~BS,H (0.25 mmol) of [ N M ~ ~ ] I [ ~ - P P ~ ~ - ~ - M 7,8-C2BgH10)1-(Lsph-)12 and [ ( ~ - S M ~ - ~ - M ~ - ~ , B - C ~ B ~ [RuC12(DMS0)4] H~O)I(120 mg, 0.25 mmol), and the mixture was (LSMe-) with [RuC12(DMS0)4]in different solvents (ethrefluxed for 3 h. An orange solid precipitated in the warm anol, THF, dimethoxyethane, toluene), at different mixture. The solution was cooled to -10 "C and the solid was stoichiometries (2:1, l:l),and at different temperatures separated by filtering, and then it was washed with deoxyhave yielded free ligand in every case. The lack of genated ethanol (20 cm3);yield 20 mg (11%). FTIR (KBr): v reaction was, initially, attributed to the difficulty of (cm-l) 2564,2551,2544 (B-H). 'H FT NMR (250 MHz, CDC13, 25 "C, TMS): d -10.70 (br, 3, BHRu), -5.55 (br, 1, BHRu), these anionic monothioethers in displacing chloride -2.87 (br, 2, B-H-B), 1.23 (s, 3, CH3), 1.51 (s, 3, CH31, 7.11completely from transition-metal complexes. To over7.60 (m, 20, Cavl-H). llB FT NMR (128 MHz, CDC13, 25 "C, come this difficulty, the ligands LSMe- and Lsph- were BF3.Et20): d 4.65 (2B), -10.31 (2B), -14.70 (2B), -17.51 (3B), or [Ru(DMSO)dCF3treated with [Ru(DMS0)61[C10~12 -20.26 (2B), -23.84 (d, 'J(B,H) = 122 Hz, lB), -28.20 (2B), SO&, two Ru(I1) complexes with weak coordinating -30.47 (2B), -37.27 (lB), -38.25 (1B). 31P{1H}FT NMR (101 ligands in the form of perchlorate or trifluoromethaneMHz, CDC13,25 "C, H3P04, 85%): d 22,93 (s), 36.53 (SI. Anal. sulfonate salts. As before, only free ligand was found. Calcd for C30H46B1&'2Ru: C, 47.00; H, 6.07. Found: C, 47.10; In summary, it can be concluded that metal coordinaH, 6.12. Red and orange microcrystals were obtained from ethyl ether/chloroform (1:l). tion surroundings with four BH units have been found X-ray Data Collection for [Ru(7-PPh2-8-Me-7,8-C2Beas RuPz(BH)4 moieties. Furthermore, the binding caHl&].2(Me)zC0 (1). Single-crystal data collection was perpacity of exo-monothiocarborane derivatives LSMe- and formed a t ambient temperature on a Nicolet P3F diffractomeLSph- does not fully parallel that of the analogous exoter using graphite-monochromatized Mo K a radiation. The monophosphine Lh-. Therefore, the P2(BH)4 surroundunit cell parameters were determined by least-squares refineing is a better stabilizing system than Sz(BH14. On the ment of 18 carefully centered reflections. Owing to the width other hand, the coordinating capability of the S(BH)2 of the reflections and very long c axis, the individual reflections moiety is increased when two triphenylphosphine ligands a t high reflection angles could not be distinguished and and a chloride fulfill the Ru(I1) octahedral environment. numerous backround imbalances were observed. Therefore, the data collection was terminated after collecting 8259 reflections. The data were then limited, and only reflections Experimental Section with 2&,, = 42" were included in the calculations. The data were corrected for decay (10%) and for absorption (v scan). Before use, methyl-o-carborane (Dexsil Chemical Corp.) was sublimed under high vacuum; [ N M ~ ~ I [ ~ - P P ~ ~ - ~ - M ~ - Numerous ~ , ~ - C ~attempts B S H ~ to O Iprepare crystals of better quality failed. Crystallographic data are presented in Table 5. was prepared from l-(diphenylphosphino)-2-methyl-1,2-di-
carba-closo-dodecaborane according to the literature.' LRuC12-
Structure Determination and Refinement of [Ru(7-
were synthesized according to the l i t e r a t ~ r e , and ' ~ RuClaxHzO was utilized a s purchased. Ethanol was reagent grade.
solved by direct methods by using the SHELXS86 program.14 Least-squares refinements and all subsequent calculations were performed using the XTAL3.2 program system,I5 which minimized the function Z w ( A W ( l l w = 02(Fo)).One of the acetone molecules and all of the methyl groups were refined a s rigid groups. The non-hydrogen atoms of the other acetone molecule were refined isotropically as individual atoms. The rest of the non-hydrogen atoms were refined with anisotropic temperature factors. The hydrogen atoms of the carborane
~)~ structure I . ~ ( Mwas ~)~CO. (DMSOLI, [Ru(DMSO)~I[C10~12, and [Ru(DMSO)~I[CF~SO~IZ P P ~ Z - ~ - M ~ - ~ , ~ - C Z B B H ~The
(8)Calabrese, J. C.; Fischer, M. B.; Gaines, D. F.; Lott, J. W. J . A m . Chem. SOC.1974, 96, 63186. (9) Hildebrandt, S. J.; Gaines, D. F.; Calabrese, J. C. Inorg. Chem. 1978, 17, 790. (10)Chizhevsky, I. T.; Lobanova, I. A,; Bregadze, V. I.; Petrovskii, P. V.; Antonovich, V. A,; Polyakov, A. V.; Yanovskii, A. I.; Struchkov, Y. T. J. Chem. SOC.,Mendeleev Commun. 1991, 47. (ll)Crowther, D. J.; Borkowsky, S. L.; Swenson, D.; Meyer, T. Y.; Jordan, R. F. Organometallics 1993, 12, 2897. (lB)Teixidor, F.; ViAas, C.; Flores, M. A. To be submitted for
nublication. (13)Evans, P.; Spencer , A,; Wilkinson, G. J . Chem. SOC.,Dalton Trans. 1973, 204-209.
(14)Sheldrick, G. M. SHELXS86, Program for Crystal Structure Solution; University of Gottingen, Gottingen, Federal Rebublic of Germany, 1986. (15lHal1, S. R., Flack, H. D., Stewart, J. M., Eds. Xta13.2 User's Guide; Universities of Western Australia and Maryland, 1992.
Agostic B-H-Ru
Organometallics, Vol. 14, No. 8, 1995 3957
Bonds in Carborane Derivatives
Table 5. Crystallographic Data for
Structure Determination and Refinement of [Ru(7-
[RU(~-PP~~-B-M~-~,~-CZ~H~O)~I.~(M~)~CO (1) and PPhz-8-Me-7,8-CzB~H*o)zl.1.486CHCls. The structure was [R~(~-PP~~-~-M~-~,~-CZB (2)S H I O )solved ~ I *by~ direct . ~ ~methodslS ~ C H C ~and S successive Fourier map calcula~~
chem formula fw a (A) b (A) c (A,
space group
T "C
1 (A) e (g ~ m - ~ ) p (cm-') transmissn coeff
C30H46BisPzRw 2(CHdzCO 880.45 11.664(9) 9.773(7) 4 1.59(3) 91.61(6) 4739(6) 4 monoclinic, P21h (NO. 14) 23 "C 0.710 69 1.234 4.2 0.903-1.000 0.067 0.060
tions. Refinements of the non-hydrogen atoms anisotropically resulted in abnormal thermal parameters and residual elecC ~ O H ~ S B I E P ~ R ~tron densities for the CHC13 solvent molecule, indicating t h a t 1.486CHC13 the solvent molecule is not fully occupied. Refinements yielded 941.4 the value 0.743(4) for the population parameter of the solvent 20.674(3) molecule. In the final refinements the non-hydrogen atoms 11.539(2) were refined anisotropically and the hydrogen atoms bonded 20.976(3) 110.92(1) to the carbaborane moiety were refined isotropically. The 4674(2) phenyl hydrogen atoms and the hydrogen atom of the solvent 4 molecule were included in the calculations in fixed positions monoclinic, with C-H = 0.95 A. The final R value was 0.066 (Rw= 0.068). C2lc Refinements were performed using the XTAL3.2 program 23 system,15 which minimized the function Cw(iFol - IFC1)*,where 0.710 69 w = l/uF2. 1.338 6.8 0.91-1.000 Acknowledgment. We are grateful to the Spanish 0.066 agencies CICYT and CIRIT (QF92-4313)for financial 0.068
moieties (except H( 10B) and H(40B)) and the phenyl hydrogen atoms were included in the calculations in fured positions (B-H = 1.10 A and C-H = 0.95 A). The final R value was 0.067 (R, = 0.060). Neutral atomic scattering factors were those included in the programs.
X-ray Data Collection for [Ru(7-PPhz-8-Me-7,8C&&Il&]*l.486CHCk(2). Single-crystal data collection was performed a t ambient temperature on a Rigaku AFC5S diffractometer using graphite-monochromatized Mo K a radiation. The unit cell parameters were determined by leastsquares refinement of 25 carefully centered reflections. Crystallographic data are presented in Table 5.
support and to Suomen Kulttuurirahasto for a grant.
Supporting Information Available: Tables giving experimental details of the X-ray crystallographic analysis, positional and thermal parameters for hydrogen atoms, anisotropic thermal parameters, and interatomic distances and angles for [Ru(L&I (1) and [RU(Lph)zI(2)(29 pages). Ordering information is given on any current masthead page. OM950003Y (16)TEXSAN-TEXRAY: Single Crystal Structure Analysis Package, Version 5.0; Molecular Structure Corp., The Woodlands, TX,1989.
