Isoselenocarbonyls via acetylenic C–Se activation

Abstract

The first examples of isoselenocarbonyl linked bimetallics arise from the chemoselective insertion of platinum(0) into the alkynyl-selenium bond of a molybdenum alkynylselenolatoalkyidyne complex.

Synthesis of a Stable Methylidyne Complex

“…Despite the considerable steric clutter associated with both the dcpe and SiPh 3 groups, this bond length is essentially identical (3 esd) with that of the precursor 2 (1.816(3) Å) and comparable to the mean value for 118 tungsten carbyne complexes (1.8264 Å) archived in the Cambridge Crystallographic Data Centre . The W1C1–Si1 bond angle (167.3(2)°) deviates significantly from the sp-C ideal 180°; however, the mean WC–A angle (173.4°) of 118 mononuclear tungsten carbyne complexes indicates that modest carbyne bending is commonplace and departures from linearity have generally been attributed to crystal-packing effects. , The angles between the carbon atoms of the carbyne and carbonyl ligands are very close to 90°, while those between the carbyne and the bulky phosphine are more obtuse (101.6(1), 95.3(1)°). Similarly obtuse angles are observed between the carbyne and picoline ligands in 2 (99.9(1), 99.4(1)°).…”

“…Angles at carbon for carbyne ligands have been observed to be as small as 163°, and such deformations are generally attributed to crystal-packing effects …”

Advances in Transition Metal Seleno‐ and Tellurocarbonyl Chemistry

“…The first binuclear selenocarbonyl was prepared in 2008 by the chemoselective insertion of platinum(0) into the acetylenic carbon‐selenium bond of [Mo(≡CSeC≡CCMe 3 )(CO) 2 (Tp*)] ( 27 ), which after initial π‐coordination of the alkyne, initially gives cis ‐[Pt{SeC≡Mo(CO) 2 (Tp*)}(C≡CCMe 3 )(PPh 3 ) 2 ] ( cis ‐ 28 ) which slowly rearranges to the trans isomer trans ‐ 28 (Scheme ) . This complex adopts the isoselenocarbonyl bridging mode (Figure d), with a formal Mo≡C triple bond and Se–Pt single bond.…”

Bi‐ and Polynuclear Transition‐Metal Carbon Tellurides

“…In contrast, CO,C S [1,4] and CSe [5] complexes have demonstrated av ariety of possible binuclear bonding modes (Scheme 1) and extensive computational studies by King and co-workers on hypothetical binuclear thiocarbonyl-carbonyl complexes have revealed the thiocarbonyl ligand(s) to bridge exclusively in preference to carbonyl co-ligands. [6] Were binuclear tellurocabonyl complexes to emerge,i tm ight therefore be anticipated that the CTel igand would also adopt abridging role.This scenario is of particular interest to us in understanding the activation of diatomic chalcocarbonyl ligands en route to bimetallic carbido complexes, [5f, 7] given CTes hould possess the most fragile C À Eb ond within group 16.…”