Dielectric and optical properties of C60 material studied by ellipsometry and quantitative IR and UV/VIS spectroscopy

The Solitary Isomer of C60H18 Is Proven to Have a C3v Crown Shape: Crystal Structure Determination and Synthesis of Its Triruthenium Cluster Complex

“…The CÀCb ond lengths in the isolated hexagon are essentially equivalent [aÀa' 1.37(2); aÀa'' 1.38(2) ] and comparablet o1 .39 f or hexamethylbenzene, [15] indicating full delocalization of three C=Cd ouble bonds throughout the ring. However,the average out-of-plane distances forc arbon atoms connected to the benzenoid ring (0.14 ) is substantially larger than that in C 60 F 18 (0.06 ), suggesting C 60 H 18 is less aromatic than C 60 F 18 .T he C(sp 3 )ÀC(sp 3 )b onds in the hydrogenated belt are elongatedt o1 .55(3) ( d Àe), 1.56(3) ( b Àc), 1.61(3) (bÀd), and 1.65(3) ( c Àc'), whereas the residual bottomh emisphere made up of 24 C(sp 2 )a toms (not connected to CH groups) have CÀCb ond lengths and C-C-C bond angles close to the normalf ullereneg eometry. [16] Notably,t he average CÀCb ond lengths is 1.544 f or dodecahedrane (C 20 H 20 ), [17] which may be considered as the smallest polyhydrofullerene, consisting of twelvepentagons only.…”

“…There are three independent but structurally similarm olecules in the asymmetric unit, one of which is depicted in Figure 1. The overall geometry resembles C 60 F 18 . [12] C 60 H 18 consists of one flattened hemisphere, to which all 18 hydrogen atoms are symmetrically bonded, and one curved hemisphere akin to the parent C 60 (Figure 2).…”

“…After filtration and evaporation of the solvent, the residue was appliedt oT LC (silica gel) and eluted with CS 2 .C rystallization of the material forming the orange-red band from n-hexaney ieldedas lightly air-sensitive, orange-red crystalline solid, characterized as [Ru 3 (CO) 9 (m 3 -h 2 ,h 2 ,h 2 -C 60 H 18 )] (1;4 3% yield based on Ru atoms). Thereafter,t reating 1 with CO (1 atm) in o-dichlorobenzene so- lution at 180 8Cf or 2hled to decomplexation to release C 60 H 18 (79 %y ield) in pure form after workup.S everal attractive features were revealed by this process:1 )The Ru 3 clusterc omplex of C 60 H 18 can be easily separated from the others;2 )the reactive C 60 H 18 cage is stabilized by donating p electrons to the ruthenium atoms and protected by the bulky {Ru 3 (CO) 9 }g roup; 3) carbonylation of 1 cleanly releases pure C 60 H 18 . Single crystals of C 60 H 18 fora nX -ray diffraction study were grown from o-C 6 H 4 Cl 2 /CS 2 /n-hexane at À20 8Cunder dinitrogen in the dark for two weeks.…”

“…The crystal structure of C 60 H 18 consists of one flattened hemisphere,t ow hich all 18 hydrogen atoms are symmetrically bonded, and one curved hemisphere akin to C 60 .Abenzenoid ring in the flattened hemisphere is isolated from the residual p systems by ab elt composed of sp 3 -hybridized CH units.T he averageo ut-of-plane distancesf or carbon atoms attachedto the benzenoid ring (0.14 ) is substantially larger than that found in C 60 F 18 3 trianglei sr egiospecifically linked to the hexagon opposite to the benzenoid ring. Compound 1 is the first transition metal complexo fapolyhydrofullerene (fullerane).C 60 H 18 and 1 have been characterized by 1 Ha nd 13 CNMR, UV/Vis, and mass spectroscopies. The HOMO-LUMO gap of C 60 H 18 is evaluated to be 1.51 Vb yc yclic voltammetry.…”

“…The UV/Vis spectrum of C 60 H 18 in CH 2 Cl 2 shows distinct absorption peaks at l = 231,2 60, and 341 nm, comparable to peaks at l = 229, 259, and 330 nm for C 60 ,a nd shoulders at l = 384 and 446 nm (see the Supporting Information, Figure S-3). [18] As ample for NMR spectroscopy was prepared under N 2 using freeze-pump-thawed deoxygenated solvents (CDCl 3 + CS 2 ,2 :1 v/v) and kept protected from light (entire decomposition of the sample had occurred after exposure to the lab lamps for 2days). For C 60 H 18 with an idealized C 3v symmetry,t here are 4d ifferent hydrogen environments and 12 types of carbon atoms (Figure 3 Figure S-4).…”