Cuneane derivative

The energy of the double bond may be raised by other means, e.g. by strain or by antiaromaticity [224]. Miller, a pioneer in the field of organofluorine chemistry, generated tetrakis(trifluoromethyl)cyclobutadiene and showed that it reacts to form a tricyclic dimer [242] which can be converted to the corresponding cubane and cuneane derivatives by ultraviolet radiation [243] (Figure 7.72). 

Cubane (CsH8), homocubane (C9H10) and 1,8-bishomocubane pentacy-clo[6.2.0.6. 0 ]decane (C10H12) are known to isomerize readily in the presence of silver ion to the related cuneane derivatives (4). The inability to calculate elaborated three-membered ring compounds accurately does not allow a quantitative estimation of the relative stabilities of these isomers to be obtained computationally. The force field calculated AH s of the cubane derivatives are... 

According to theoretical calculations [114], the most stable modification of a neutral P8 ligands is expected to be the cuneane structure (C), which is found in the phosphorus allotrope known as Hittorff s phosphorus [115,116]. Surprisingly, a ligand conforming to this structural motif has been stabilized in the mixed iron/iridium complex [ Cp Ir(CO) 2(p,q2 2 1 1 1-P8) Cr(CO)5 3] (90), prepared either by photolysis or thermolysis of [Cp Ir(CO)2] with P4 in the presence of excess [Cr(CO)5(thf)] (Scheme 4) [35]. The same unit has also been recognized in the iron derivatives [[CpMeFe(CO) 2(p,q2 2 l l-P8)[CpMeFe(CO)2 2]... 

Skeletal rearrangements of some strained compounds, such as bulvalene to bicyclo[4.2.2]deca-2,4,7,9-tetraene, cubane to cuneane, hexamethyl Dewar benzene to hexamethylbenzene (eq 52), and quadricyclane to norbornadiene (eq 53), are catalyzed by derivatives of PdCl2. 

However, Polesi and Miller reported in 1976 that irradiation (450 W high-pressure Hg lamp) of a perfluoro-derivative of ti-tricyclo[4.2.0.0 ]octa-3,7-diene in a fluorocarbon solution yielded perflu-orooctamethylcubane 30 (ca. 20%) and perfluorooctamethylcuneane 31 (15%) (Scheme 4). They postulated that the cubane 30 and cuneane 31 were formed from the syw-isomer 29 and the semibuUvalene 32, respectively. ... 

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