The photochemical reaction of 1,2-digermacyclobutane with C60: possible example of a closed [6,5]-bridged fullerene derivative of germacyclopropane

[6,6]‐Open and [6,6]‐Closed Isomers of C70(CF2): Synthesis, Electrochemical and Quantum Chemical Investigation

“…The 13 C NMR spectrum of C 70 (CF 2 )‐I features 34 sp 2 carbon atom signals in the range δ =124–153 ppm plus two triplet signals at δ =69.4 ( 3 J (C,F)=23 Hz) and 102.8 ppm ( 1 J (C,F)=285 Hz) attributed to the bridgehead sp 3 carbon atoms and the sp 3 carbon of the CF 2 group, respectively. The signals observed within the range δ =68–80 ppm are typical for bridgehead carbon atoms of methanofullerenes, as follows from the literature data obtained for [5,6]‐closed C 60 (GeR 2 ),15 [6,6]‐closed C 60 (CR 2 ), R=H, Cl, Br, I,16–19 and C 70 (CCl 2 ) 20. The 13 C NMR spectrum of C 70 (CF 2 )‐II contains 35 sp 2 carbon atom signals in the range δ =125–155 ppm, a triplet signal at δ =111.6 ppm ( 1 J (C,F)=257 Hz; CF 2 ) and two triplet signals at δ =99.2 and 98.2 ppm ( 3 J (C,F)=37.4 and 38.5 Hz, respectively).…”

“…For example, CF 2 chemical shift values for saturated 7,7-difluoronorcarane [12] are d F = À129 and 159 ppm; for 11,11-difluoro-1,6-methano- [10]annulene [13] and difluorocyclopropabenzene, [14] which contain sp 2 -bridgehead carbon atoms, d = À126.2 and À80.4 ppm, respectively. [15] [16][17][18][19] and…”

23 Fullerenes

“…184 The photochemical reaction of a 1,2-digermacyclobutane derivative containing bulky bistrimethylsilylmethyl ligands with [60]fullerene is reported to produce the first example of a closed [5,6] adduct of [60]fullerene. 185 Copper() complexes react with hexaaza [60]fulleroids (open hexakis- [5,6] adducts) producing polymetallated [60]fullerene derivatives such as C 60 [(NR)Cu(MeCN) 2 -(ClO 4 )] 6 . 186…”

A Computational Study of the Mechanism of Addition of Singlet Carbene Analogues to 1,3-Butadiene to Form 1,1-Dimethylmetallacyclopent-3-enes [MMe2C4H6, M = Si, Ge, Sn] and Their Reverse Retro-addition Reactions

“…1b,2a,b,4,5 Addition reactions of carbenes to multiple bonds are well documented, [6][7][8] and the cyclopropane products of their addition to olefins are abundant. While silicon analogues of these products, siliranes, are well known, 1b,h,9-11 and there are two examples 12,13 of stable germiranes and considerable evidence for their intermediacy, 1b,2b the existence of stanniranes remains to be established. Carbenes add to 1,3-butadiene to form their 1,2addition products vinylcyclopropanes (Scheme 1).…”