Octahedrane

A structural determination1057 of CsCdCl3 reveals a polymer containing two distinct types of cadmium ion. One is surrounded by six chloride ions in a near perfect octahedron (Cd—Q = 2.60 A), while the other is surrounded by two distinct groups of chloride ions (Cd—Cl = 2.64, 2.59 A) in a distorted octahedran. Alternatively, Raman spectral studies on [Pr"N] [CdX3] (X = Cl, Br or I) indicate discrete [CdX3] anions possessing Qtv symmetry.1058... 

The molecule of/7-[3. 5 ]octahedrane (227) has the rare point group symmetry, and forms tetragonal crystals in space group R-3c. The structure of its 2, lO-COOMe derivative (228) has also been determined ". The bond in the three-membered ring in 227 is 1.507 (4) A, while the bonds adjacent to the substituent in 228 are longer, 1.529 (1) A, the distal bonds shorter, 1.495 (1) A. 

Case Study 6.14 Synthesis of cage compounds - octahedrane... 

Experimental details.83S A solution of diazacyclophane (236 50 pniol) in benzene (10 ml) in a quartz tube was purged with nitrogen and irradiated in a Rayonet photoreactor (Figure 3.10) equipped with 16 fluorescent lamps (2 = 300 nm, 25 W each) at room temperature for 36 h. The solution was concentrated under reduced pressure and the residue was separated repeatedly by preparative TLC to afford octahedrane in 33% chemical yield. 

Reduction of the diester 91 yielded the bis(hydroxymethyl)octahedrane 97. Treatment of 97 with superacid led to the interesting cage dication 98 which according to its NMR data must be regarded as a bis(bicyclobutonium) ion (Scheme 21) [78]. The positive charge in the dication 98 is significantly delocalized into the cyclopropane rings. 

Octahedrane does not seem to be a stationary point (minimum, transition state, or higher-order saddle point) at the HF/6-31G, MP2/6-31G or 3LYP/6-31G levels. 

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