Geminale substituenteneffekte
1990; Elsevier BV; Volume: 160; Issue: 2 Linguagem: Inglês
10.1016/0040-6031(90)80255-w
ISSN1872-762X
AutoresKatharina Fritzsche, Barbara Dogan, Hans‐Dieter Beckhaus, Christoph Rüchardt,
Tópico(s)Thermal and Kinetic Analysis
ResumoThe heats of combustion of 1-nitroadamantane (1), 2-nitroadamantane (2), 2,2-di-nitroadamantane (3) and 2-cyano-2-nitroadamantane (4) were measured by combustion calorimetry, and the heats of sublimation were derived from the temperature dependence of the vapour pressure measured in a flow system. The results for ΔHXXXc(c) and ΔHSub (in kJ mol−1, standard deviation in parentheses) are: 1, −5824.1 (±2.2) and 63.6 (±1.0); 2, −5841.0 (±2.2) and 58.0 (±2.3); 3, −5685.2 (±1.0) and 96.4 (±1.4); 4, −6238.4 (±1.5) and 70.0 (±1.9). A comparison of the resulting heats of formation ΔHXXXf(g) (in kJ mol−1, standard deviation in parentheses) for 1 = −191.1 (± 2.4), 2 = −179.8 (±3.2), 3 = −154.3 (±1.7) and 4 = −21.0 (±2.5) reveals a destabilizing interaction of the geminal substituents in 3 and 4 amounting to 59 kJ mol−1 (nitro/nitro) and 33 kJ mol−1 (nitro/cyano) respectively. Die Verbrennungsenthalpien von 1-Nitroadamantan (1), 2-Nitroadaman-tan (2), 2,2-Dinitroadamantan (3) und 2-Cyano-2-nitroadamantan (4) wurden kalorimetrisch bestimmt, die Sublimationsenergien aus der Temperaturabhangigkeit der Dampfdriücke abgeleitet, die mil der Überführungsmethode gemessen wurden, ΔHXXXc(c), ΔHSub [kJmor−1 (Standardabw.)]: 1 = −5824,1 (±2,2), 63,6 (± 1,0); 2 = − 5841,0 (±2,2), 58,0 (± 2,3); 3 = − 5685,2 (±1,0), 96,4 (± 1,4); 4 = −6238,4 (± 1,5), 70,0 (± 1,9). Der Vergleich der daraus ermittelten Standardbildungsenthalpien ΔHXXXg (g) [kJ mol−1 (Standardabw.)] für 1 = −191,1 (±2,4); 2 = −179,8 (±3,2); 3 = −154,3 (±1,7) und 4= -21,0 (±2,5) mil aus Gruppenelementen ermittelten Werten ergibt eine destabilisierende Wechselwirkung für geminale Substituenten: in 3 von 59 kJ mol−1 (Nitro/Nitro) und in 4 von 33 kJ mol−1 (Nitro/Cyano).
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