Tetrahedral fullerene

Two redox states of one complex, (168) and (169), exhibit very similar respective values of ca. 0.6 J cm-2 and 0.7 J cm-2 with 32 ps pulses at 532 nm (in benzene).452 A 532 nm OL study of the two neutral complexes (170) and (171) using ns and ps pulses has also been reported.453-455 Low values of ca. 0.3 Jem-2 are observed with ps pulses in benzene, and both ps time-resolved pump-probe and Z-scan measurements reveal that RSA and nonlinear refraction are responsible for the OL behavior.453-455 Because (170) and (171) are transparent in the region 400-900 nm, their OL responses should cover a wider range than those of fullerenes and MPcs.453-455 Dai et al. have applied ps 532 nm DFWM to the tetrahedral Zn11 or Cd11 complexes (172) and (173), the modest 7 responses of which are resonance enhanced by the n- 7r transition at 512nm.456 The dimeric square pyramidal Zn11 complex (174) exhibits a broad n —> tt absorption with Amax = 497 nm in DMF and is shown by 532 nm Z-scan to exhibit SF behavior.457... 

Hirsch and co-workers calculated NICS values for tetrahedral clusters of N, P, As, Sb, and Bi, as well as for the corresponding tetra-anions composed of Si, Ge, Sn, or Pb atoms, finding diatropic values for 2,n(n 1) jr-systems.296a b It was postulated by Hirsch, Schleyer, and their co-workers that for icosahedral fullerenes and their hetero-analogues the Hiickel rule, involving 4/2+2 //-electrons, should be replaced by the 2(/2+l)2 electron rule.296... 

Intermediates and artificial ("forced ) tetrahedral molecules inside fullerenes 95... 

Figure 1 The structures of endohedral fullerenes with encapsulated tetrahedral MX molecules and...

Figure 14. Unit cells of fullerite with bcc (a) and fee (b) structures with lattice hydrogen only. (Shaded circle) Sites of crystalline lattices, in which fullerenes molecules are distributed ( ) octahedral (O) interstitial sites (o) tetrahedral...

The relief of strain in the fullerene cage is the primary driving force for addition reactions, by altering the hybridization of the reacting fullerene carbon atoms from a trigonal sp2 to a less strained tetrahedral sp3 configuration. 

Peculiarity of the fullerene molecule formation also reveals itself in a fullerite crystal structure. Cubic crystal lattices of fullerites and hydrofullerites behave like those of different metals and alloys. Fullerene molecules are distributed in the lattice sites while atoms of elements are distributed in the octa- and tetrahedral interstitial sites forming the interstitial solid solutions. Fullerene molecules substitute each other in the sites of lattice and form the substitution solid solutions. Forming exo- and endocompounds, fullerene molecules that are in the lattice sites can change considerably the properties of crystal, whereas its crystalline structure remain unchanged. 

The room-temperature conductivities of these compounds are usually about one or two orders of magnitude smaller than those shown in Table 12.2. Included in Table 12.3 are the superconducting (but very air-sensitive) alkali metal and alkaline earth fullerides these are compounds with three-dimensional superconductivity, where the alkali metal ions are just gegenions tucked in tetrahedral and octahedral holes in the cubic fullerene crystal structure [36]. The critical temperatures of ET salts seem to be stuck at... 

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