Photolysis of dicarbonyl(cyclopentadiene)rhodium complexes with a pendent alkyne unit

Bimetallic Reactivities of Dinuclear Iridium and Rhodium Complexes Generated from Two Types of Alkyne‐Containing Bisphosphine Ligands

“…Structures of a series of dinuclear iridium complexes 5 – 8 , 10 – 12 and rhodium complex 14 were unambiguously determined using X‐ray crystallographic analyses (Figure and Table ) . The C–C bond lengths of the 1,3‐butadiene‐1,4‐diyl moiety of all the complexes show apparent bond alternation of 1,3‐dienes, which are also presented in our previous report as well as Gleiter's and Power's reports , . In all iridium complexes, two metal atoms are bridged by a 1,3‐butadiene‐1,4‐diyl component whose termini are covalently bound to each iridium center [C(1)–Ir(1) and C(4)–Ir(2)], and whose alkene moieties also coordinate to each iridium atom in η 2 ‐fashion [C(1)=C(2) to Ir(2) and C(3)=C(4) to Ir(1)].…”

“…The metal centers in the flyover‐type dinuclear complexes contain both σ‐ and π‐coordinations from carbon‐based butadiene‐1,4‐diyl ligand backbone. Gleiter and Power reported pioneering works on dirhodium and diiron complexes , . However, their reactivities remain unclear because of robustness of structures toward ligand exchange.…”

Transition Metal Acetylide Rearrangement and Coupling Induced by Coordinative Unsaturation

“…Unlike the normal planar geometry of the five-membered C 4 M ring and unequal metal centers observed in metallacyclopentadiene complexes, ,− which are usually formed via coupled alkynes, complex 1 shows a rather distorted geometry of the C 4 M ring and similar iron(I) environment. Binuclear transition metal complexes with 1,3-butadiene-1,4-diyl ligands are rare, and structurally characterized examples are limited to {ArNC(H)C(H)NAr} 2 Ni 2 {(H)CC(CH 2 OCH 3 )} 2 (Ar = C 6 H 3 -2,6- i Pr 2 ) and Rh 2 {μ 2 ,η 5 ,η 2 ,η 2 ,η 5 -(3-C 6 H 5 -C 5 H 3 )-(CH 2 ) 3 CC( t Bu)C( t Bu)C(CH 2 ) 3 -(3-C 6 H 5 -C 5 H 3 )}, which were also prepared by alkyne coupling. The Fe···Fe separation in 1 is 2.5559(3) Å, which is slightly longer than the sum (2.48 Å) of the single-bond covalent radii for iron .…”