Reactions of the Dinuclear Ruthenium Complex {(η⁵-C₅H₃)₂(SiMe₂)₂}Ru₂(CO)₄, Featuring a Doubly Linked Dicyclopentadienyl Ligand

Abstract

The complex {(η 5 -C 5 H 3 ) 2 (SiMe 2 ) 2 }Ru 2 (CO) 4 (1), which features the doubly linked dicyclopentadienyl ligand (η 5 -C 5 H 3 ) 2 (SiMe 2 ) 2 , reacts with phosphines (PMe 3 , PCy 3 , PPh 3 ) to give {(η 5 -C 5 H 3 ) 2 (SiMe 2 ) 2 }Ru 2 (CO)(µ-CO) 2 (PR 3 ) (2a-c), with halogens X 2 (X ) Cl, Br, I) to give the Ru-Ru-cleaved products {(η 5 -C 5 H 3 ) 2 (SiMe 2 ) 2 }Ru 2 (CO) 4 (X) 2 (3a-c), with X 2 and AgTfO to give [{(η 5 -C 5 H 3 ) 2 (SiMe 2 ) 2 }Ru 2 (CO) 4 (µ-X)] + TfO -(X ) Cl, Br, I; 4a-c), and with SnCl 2 to give {(η 5 -C 5 H 3 ) 2 (SiMe 2 ) 2 }Ru 2 (CO) 4 (µ-SnCl 2 ) (5), resulting from the insertion of SnCl 2 into the Ru-Ru bond. Reduction of 1 with Na/Hg generates [{(η 5 -C 5 H 3 ) 2 (SiMe 2 ) 2 }Ru 2 (CO) 4 ] 2-(6), which reacts with (η 5 -C 5 H 5 ) 2 TiCl 2 to give {(η 5 -C 5 H 3 ) 2 (SiMe 2 ) 2 }Ru 2 (CO) 4 {µ-Ti(η 5 -C 5 H 5 ) 2 } (7). Ultraviolet photolysis of 1 with diphenylacetylene and phenylacetylene yields a series of five dinuclear Ru complexes (8-10, 12, 13) containing one or two bridging acetylene units. The rigidity of the doubly linked (η 5 -C 5 H 3 ) 2 (SiMe 2 ) 2 ligand substantially influences the reactivity and structures of the complexes. Molecular structures of 1, 2a, 3c, 5, 9, 10, and 12 as determined by X-ray diffraction studies are also presented.

Synthesis, structures and reactions of doubly bridged biscyclopentadienyl diruthenium complexes (CR2)(EMe2)[(η5-C5H3)Ru(CO)2]2 (R = Me, H; E = Si, Ge)

“…These molecules deviate from C 2v symmetry only slightly (for complex 2, see the right drawing in Fig. 3), as reflected by their respective minor torsion angle (:Cp(centroid)eRu(1)eRu(2)eCp(centroid): 5.9 for 2; 8.4 for 5; 3.4 for 7; 2.4 for 10), which is much smaller than that (24.2 ) in its analogue (SiMe 2 ) 2 [(h 5 -C 5 H 3 )Ru(CO) 2 ] 2 [13]. The bend of the doubly bridged ligands, defined as the angle between the planes of two Cp rings, is relatively large (131.5 for 2; 130.7 for 5; 131.7 for 7; 130.7 for 10).…”

“…The bend of the doubly bridged ligands, defined as the angle between the planes of two Cp rings, is relatively large (131.5 for 2; 130.7 for 5; 131.7 for 7; 130.7 for 10). So nonbonding interactions between highly symmetrical and eclipsed carbonyl ligands and strain resulting from bending the normally planar doubly bridged ligands might be two main factors which lead to significantly greater RueRu bond distances than those in the respective non-bridged and singly bridged biscyclopentadienyl diruthenium analogues ( [5], and even its double-bridged analogue (SiMe 2 ) 2 [(h 5 -C 5 H 3 )Ru(CO) 2 ] 2 (2.8180(3) Å) [13]. This hypothesis is also supported by single crystal X-ray structural data for the series…”

“…The molecular structure of 12 was confirmed by single-crystal X-ray determination, which contains not only a terminal iodine atom, but also a bridged iodine atom at the same time, as a neutral molecule. However, the similar products containing the bridged-halogen unit are not detected in reactions of the respective non-bridged and singly bridged biscyclopentadienyl dimeric carbonyl analogues, and even the doublebridged analogue (SiMe 2 ) 2 [(h 5 -C 5 H 3 ) 2 Ru 2 (CO) 2 ] 2 with X 2 (X ¼ Cl, Br, I) [13]. This difference in reactivity might arise from the rigid (CMe 2 )(SiMe 2 ) doubly bridged biscyclopentadienyl ligand or the elongated RueRu bond in complex 2, which provide an appropriate environment for formation of novel complex containing bridgedhalogen unit.…”

“…In addition, complex 12 could also be obtained from the reaction of complex 11 with an excess of I 2 (Scheme 3). We also extended the reaction scope to Br 2 subsequently, and obtained the similar bromo-products (CMe 2 )(SiMe 2 )[(h 5 -C 5 H 3 )Ru(CO) 2 Br] 2 (13) and (CMe 2 )(SiMe 2 )[(h 5 -C 5 H 3 ) 2 Ru 2 (CO) 3 (Br)](m-Br) (14), although the yields were fairly low (Scheme 3).…”

Ferrocene bridged and substituted tetramethylcyclopentadienyl (or indenyl) carbonyl complexes of iron, ruthenium, and molybdenum

“…This makes the Ru-Ru and Fe-Fe bond distance [2.7785(11), 2.568 Å ] in 2 and 3 longer than those in the unbridged and many bridged analogues (Table 4). It is reported that the bridging carbonyl groups tend to shorten metal-metal distances [22], and the dicyclopentadienyl dinuclear metal complexes without the bridging carbonyls usually show longer M-M distances that those with the bridging carbonyls. So the Ru-Ru bond distance in 2 is the longest one among the dicyclopentadienyl tetracarbonyl diruthenium complexes with the bridging carbonyls, and even longer than those in (CH 2 ) [(g 5 -C 5 H 4 )Ru(CO) 2 ] 2 [2.766(1) Å ] [23], which has no the bridging carbonyls.…”