Synthesis of novel fullerene complex: the [4+2] cycloadduct of (bicyclo[3.2.0]hepta-1,3-dienyl)cobalt(I) complex with C60

π Complexes with Annellated Cyclobutene Rings: Bicyclo[3.2.0]heptadienyl Anion and Benzocyclobutene as Ligands for Transition Metals

“…23 was obtained in 28% yield along with a diadduct (12%) and showed interesting structural aspects and electrochemical behviour. 15 To our knowledge 23 is the first cobalt complex with a C 60 incorporated.…”

“…2 When anion 13 was treated with ClCo[P(OiPr) 3 ] 3 followed by 1,5-cyclooctadiene (COD) cobalt complex 15 was obtained in 49% yield from 12. 15 showed interesting behaviour in the 1 H NMR when compared with the known [4][5][6] next higher homologue 16: Whereas the chemical shift difference ∆δ between 3-H and the neighbouring 2(4)-H was 0.14 ppm for 16 it was -1.67 ppm for 15! A possible explanation was found by comparison of the crystal structure analyses of both complexes.…”

“…The reaction was tested with a number of other dienophiles with formation of cycloadducts 21-23. [13][14][15] The cycloadduct 23 with C 60 fullerene was prepared in a cooperation with Professor M. Iyoda, Tokyo Metropolitan University. 23 was obtained in 28% yield along with a diadduct (12%) and showed interesting structural aspects and electrochemical behviour.…”

Diels-Alder Additions as Mechanistic Probes–Interception of Silyl-Isoindenes: Organometallic Derivatives of Polyphenylated Cycloheptatrienes and Related Seven-Membered Rings

“…The molecular structure of the cation, 13 , and of the crystal packing, are shown as Figure 9 and Figure 10 and reveal that the seven-membered ring is not planar but adopts a shallow boat conformation such that the interplanar angles between C(6)-C(7)-C(1) [plane 1], C(1)-C(2)-C(5)-C(6) [plane 2], and C(2)-C(3)-C(4)-C(5) [plane 3] are 13° for [plane 1/plane 2] and 18° for [plane 2/plane 3], noticeably less bent than those found for the precursor C 7 Ph 7 H. The peripheral phenyls are each twisted very markedly out of the plane containing their attached central ring carbon and neighbouring ring atoms by 76°–82° (average 80°), and may be compared to the values for dihedral angles found in C 6 Ph 6 (67°–75°) [ 33 , 34 ], (η 5 -C 5 Ph 5 )ML n complexes (~50°) [ 35 , 36 , 37 ], (η 4 -C 4 Ph 4 )ML n complexes (average ~36°) [ 38 , 39 ] and for the [C 3 Ph 3 + ] cation (~5°) [ 40 , 41 ].…”

C60-Linked Carboxylic Acid and Its Derivatives by Diels-Alder Cycloaddition of C60 with a Buta-1,3-diene Bearing an Electron-Withdrawing Group

“…The Diels-Alder reaction has been demonstrated to be one of the most reliable methods for functionalization of C 60 since the pioneering work by Wudl et al, who first showed the remarkable reactivity with cyclopentadiene and anthracene. 1 The cumulative results revealed that (i) the low lying LUMO level is advantageous for this type of cyclization (e.g., C 60 has nearly the same reactivity as Nphenylmaleimide 2 ), (ii) the addition occurs selectively at the 6,6-ring junction without exceptions, 3 (iii) the number of the addends (i.e., monoadduct vs polyadduct) is controlled with relative ease unless excess amount of reagent is used, and (iv) cycloreversion is sometimes observed, but avoided by incorporating the forming double bond into an aromatic ring as is shown in the case of o -quinodimethanes 4 or by converting the formed double bond to a single bond as was shown in the case of 2-silyloxy-1,3dienes. 2,5 In our previous work, the Diels-Alder reactions of C 60 with buta-1,3-dienes bearing an electron-withdrawing substituent was shown to occur effectively to give α , βunsaturated ethoxycarbonyl-, acetyl-, cyano-, sulfonyland nitro-functionalized derivatives.…”