Synthesis and Theoretical Analysis of Palladium(II) Complexes Containing a .eta.1 Metallacarbyne Ligand

The Potential of Palladacycles: More Than Just Precatalysts

“…For the initial insertion, theoretical and experimental studies have pointed to an η 2 -preinsertion scenario as in Chart . Both structural and theoretical studies involving isolobal metallacarbynes have shown an alternative η 1 coordination mode of the carbyne to palladium . From an early stage, the alkyne insertion process was found to be a useful method for the synthesis of heterocycles (Scheme ).…”

Theoretical Studies in Palladium and Platinum Molecular Chemistry

“…Related to all these alkyne complexes are the metallacarbyne complexes of Pd(II) that have been analyzed in a joint experimental and theoretical study . The experimental systems are of the type shown in 4 , displaying an unexpected η 1 mode of bonding.…”

Carborane Complexes of Ruthenium: Synthesis of the Bimetal Compounds [MRu(μ-CC6H4Me-4)(CO)4(η5-7,8-C2B9H11){κ3-HB(pz)3}] (M = Mo or W) and Their Reactions with Sulfur and Selenium,

“…Relevant to consideration of the bonding in the ring systems of the complexes under discussion are studies reported on compounds containing [M(⋮CC 6 H 4 Me-4)(CO) 2 ( η 5 -C 5 H 5 )] groups coordinated in an η 1 manner to Pd(II). In the molecule [WPdCl( μ -CC 6 H 4 Me-4)(CO) 2 (bhq)( η 5 -C 5 H 5 )] (bhq = benzo( h )quinoline) the W−Pd distance is long (2.8001(6) Å), suggesting a weak bonding interaction, and the W− μ -C−Pd angle is 89.27(2)°.…”

“…These structural features are similar to those for 2b and 4b . The ring bonding in the palladium−tungtsen complex was interpreted in terms of the tungstacarbyne molecule being bound to the palladium essentially through the alkylidyne−carbon atom (Chart , A ) . This maximizes the strong Lewis acid character of the Pd(II) center, while weak donation from the Pd d z 2 orbital into the π* orbital of the tungstacarbyne is possible.…”

“…The compounds 4 are the first molecules to be reported in which tolylmethylidyne groups bridge Ru(CO) 2 ( η 5 -7,8-C 2 B 9 H 11 ) and M(CO) 2 { κ 3 -HB(pz) 3 } fragments, the nature of the bridging alkylidyne system being of interest in the context of earlier studies. , The complexes [MRu( μ -1 κ C α ,1:2 κ E -ECC 6 H 4 Me-4)(CO) 4 ( η 5 -7,8-C 2 B 9 H 11 ){ κ 3 -HB(pz) 3 }] ( 6, E = S or Se) have unique structures in which M(CO) 2 ( η 2 -ECC 6 H 4 Me-4){ κ 3 -HB(pz) 3 } fragments are stabilized by attachment of Ru(CO) 2 ( η 5 -7,8-C 2 B 9 H 11 ) units to the sulfur and selenium atoms.…”