Reversible Interconversion between μ,η²:η²- and μ₃,η²:η²:η²-C₆₀ on a Carbido Pentaosmium Cluster Framework

Abstract

Decarbonylation of Os 5 (CO) 14 (PPh 3 ) by 2 equiv of Me 3 NO/CH 3 CN at room temperature followed by reaction with C 60 in refluxing chlorobenzene produces Os 5 C(CO) 11 (PPh 3 )(µ 3 ,η 2 : η 2 :η 2 -C 60 ) (1) in 44% yield. Thermal treatment of 1 at 80 °C under 1 atm of carbon monoxide affords Os 5 C(CO) 12 (PPh 3 )(µ,η 2 :η 2 -C 60 ) (2) in good yield (72%). Upon thermolysis of 2 at 132 °C, 2 is cleanly reconverted to 1 (73%) by loss of a carbonyl ligand. Reaction of 1 with benzyl isocyanide at room temperature gives the addition product Os 5 C(CO) 11 (CNCH 2 C 6 H 5 )(PPh 3 )-(µ 3 ,η 2 :η 2 :η 2 -C 60 ) (3) in 85% yield. Thermolysis of 3 at 100 °C forms the isomeric Os 5 C(CO) 11 -(CNCH 2 C 6 H 5 )(PPh 3 )(µ,η 2 :η 2 -C 60 ) (4) in 64% yield. Treatment of 4 with 1 equiv of Me 3 NO/ CH 3 CN at room temperature followed by heating at 132 °C in chlorobenzene gives Os 5 C(CO) 10 (CNCH 2 C 6 H 5 )(PPh 3 )(µ 3 ,η 2 :η 2 :η 2 -C 60 ) (5) in 71% yield. Compound 5 can be alternatively prepared from the reaction of 1 with excess Ph 3 PdNCH 2 Ph at room temperature in 59% yield. Heating a chlorobenzene solution of 5 at 55 °C under 3 atm of carbon monoxide produces 4 as the only major product (16%). Treatment of Ru 5 C(CO) 11 (PPh 3 )(µ 3 ,η 2 :η 2 :η 2 -C 60 ) (1′) with benzyl isocyanide at room temperature forms Ru 5 C(CO) 11 (CNCH 2 C 6 H 5 )(PPh 3 )(µ 3 ,η 2 : η 2 :η 2 -C 60 ) (3′) in 90% yield. Reaction of 1′ with benzyl isocyanide at a slightly elevated temperature of 40 °C affords Ru 5 C(CO) 10 (CNCH 2 C 6 H 5 )(PPh 3 )(µ 3 ,η 2 :η 2 :η 2 -C 60 ) (5′) in an almost quantitative yield of 96%. Compounds 1-5, 3′, and 5′, isolated as crystalline solids, have been characterized by microanalytical and spectroscopic methods. Molecular structures of 1-4 and 5′ have been elucidated by X-ray crystallographic studies.

Transition Metal Complex Formation

“…This new complex is one of the rare examples for a M-C 60 σ-bond. One further example, where C 60 can act as a four-electron ligand is the fullerene carbido pentaosmium cluster complex 28 shown in Scheme 7.13 [75,76]. Heating 26 with an excess of PPh 3 under pressure in chlorobenzene leads to the loss of one coordination site.…”

“…Such complexes are known for the clusters Os 5 C [75,76], Ru 5 C [77][78][79], Ru 6 C [78], PtRu 5 C [77] and Rh 6 [80]. Such complexes are known for the clusters Os 5 C [75,76], Ru 5 C [77][78][79], Ru 6 C [78], PtRu 5 C [77] and Rh 6 [80].…”

[60]Fullerene–Metal Cluster Complexes: Understanding Novel η1 and η2[6:5] Bonding Modes of Metallofullerenes

“…Shapley et al [32][33][34] and Park et al [35][36][37][38][39] independently prepared various L n M x (C 60 ) y complexes and demonstrated that a variety of cluster frameworks [Re 3 (µ-H) 3 , Ru 3 , Os 3 , Ru 5 C, Os 5 C, PtRu 5 C, Ru 6 C, and Ru 6 ] can bind to C 60 through a face-capping cyclohexatriene-like bonding mode: µ 3 -η 2 ,η 2 ,η 2 -C 60 . The metallofullerene complexes with this relatively strong bonding mode exhibited remarkable thermal and electrochemical stabilities, uniquely suitable for various device applications, which is in contrast to other previously known η 2 -C 60 metal cluster complexes.…”

GEOMETRICAL CONFIGURATION AND ELECTRONIC STRUCTURE OF C60 FULLERENE MOLECULE UNDER EXTERNAL ELECTRIC FIELD

“…[1][2][3][4] In the carbon fullerene molecules, C 60 attracts one's attention by its excellent physical and chemical stability, and many investigations on its chemical, optical, and electronic properties have been published. [1][2][3][5][6][7] Now some theoretical work on the polarizability of C 60 fullerene under the external electric field has been carried out. For example, in Ref.…”