COM MU N ICATIONS
verts readily to the dinuclear ring-opened compound 3, or is desulfurized to afford cluster 4. A single-crystal X-ray structure for 2 (see Fig. 2) was needed to establish the mode of bonding. The desulfurized ligand is bonded to three metal atoms as a n 10-electron donor to give a 50-electron cluster with only two Ru-Ru bonds. T O(311 Fig. 2 Molecular structure of 2: selected bond lengths [A] and angles [ 1: Ru(1)-Rui2). 1.946(2): Ru(Z)-Ru(3), 2.781(2): Ru(2)-C(7), 2.257(5j; Ru(2)-C(8), 2.237 5). l . 4 l i l ) ; C(5)-C(6), 1.424(8): C(6)-C(7). 1.45XiX); C(7)-C(8). 1.400(9); C(1) ~C i 6 ) . 1.454(8); Ru(l)...Ru(3) . 3.815(2): R u ( 2 ) . . . C ( l ) . 2.934(6): Ru(2) . C(6). 2.657(6): Ru(l)-Ru(2)-Ru(3). 83.5(1): Ru(l)-C(l)-Ru(3). 119.6(2); Ru(3)-CIl)-C(6). 113.9(4); Ru(l)-C(l)-C(6), 72.9(3); Ru(3)-C(X)-C(7), 116.8(4); Ru(3)-CiX)-C(7), 72.7(3): C(2)-Ru(l)-C(5). 76.0(2); C(3)-Ru(l)-C(6). 75.6(2); Ru(l )-Ci6)-C(7). 128.3(3): Ru(2)-C(7)-C(6). XX.6(3).
[Ru,(C,H,)(CO),] (2) is the first example of a fully characterized trinuclear Ru complex containing a I-ruthenaindene system. The nine atoms of the bicyclic metallaindene system are substantially coplanar; the C,H,Ru(CO), unit can thus be regarded as an 8-electron-donor ligand n-complexed to the Ru,(CO), group.
E.xprrinwntal Procrdzrrr
[ R U , [ C O ) ~~] (0.200 g) and 1 (0.200g) were heated at reflux in tetrahydrofuran (50 cni') for 24 h under N,. The orange-brown solution was evaporated to dryness under reduced pressure. and the residue separated by TLC on silica with n-hexane 'IS eluent into three bands. which yielded 2 (yellow, 2X%). 3 (yellow-orange, 17%). and4(yellow. 10%).Asolutionof2(0.020g)inCDCI,(0.5 cm3) underCO(1 atm) showed complete conversion to compound 4 in 24 h at room temperature (monitored by ' H NMR spectroscopy). Crystals ofcompound 2 for structure determination were obtained fi-om cyclohexane. 2: IR (cyclohexane): 17(CO) [cm-'1