Synthesis, microwave spectrum, and ab initio calculations for difluorocyclopropenone

Abstract

state and gas-phase structures recently noted for (CH3)3N-S0227 (0.21 Á) is encouraging in this respect, as it demonstrates the possibility of a substantial "dynamic range" in N-S bond lengths. ConclusionMicrowave spectroscopy has been used to observe the gas-phase adduct formed between CH3CN and BF3. The structure has been determined to be intermediate between the limits normally expected for van der Waals and covalent interactions and is significantly different from that observed in the crystalline material. The correlation between the boron-nitrogen bond length and the N-B-F angle in a series of BX3 species with nitrogen donors provides the first gas-phase example of a structure correlation analogous to those used frequently to map reaction paths in crystalline systems.Acknowledgment. The support of the National Science Foundation (Grant No. CHE-8807895) and the McKnight Foundation is gratefully acknowledged. We are also grateful to Ms. Robin Jurgens-Lutovsky and Prof. Jan Alrnlof for making the results of their ab initio study known to us prior to publication and to Prof. R. L. Kuczkowski for providing us with a preprint of his work on (CH3)3N-S02.

An Ab Initio and Density Functional Theory Study of Keto−Enol Equilibria of Hydroxycyclopropenone in Gas and Aqueous Solution Phase

“…This, however, is in marked contrast to other three- and even five- and seven-membered cyclic conjugated ketones, which have been the subject of a number of experimental − and theoretical studies − where their chemical and physical properties have been investigated. One well-known example is the seven-membered species tropolone (2-hydroxy-2,4,6-cycloheptatrien-1-one), which has also been studied extensively. − Tropolone is of interest in relation to the present study on hydroxycyclopropenone in that it may undergo tautomeric equilibriation between the keto and enol forms as it provides an example of an aliphatic carbonyl compound possessing hydrogens α to the carbonyl group.…”

“…This, however, is in marked contrast to other three-and even five-and seven-membered cyclic conjugated ketones, which have been the subject of a number of experimental [7][8][9][10][11] and theoretical studies [12][13][14][15][16][17][18][19] where their chemical and physical properties have been investigated. One well-known example is the seven-membered species tropolone (2-hydroxy-2,4,6-cycloheptatrien-1-one), which has also been studied extensively.…”

Cyclopropenylium Cations, Cyclopropenones, and HeteroanaloguesRecent Advances

“…231 Photolysis of difluoromaleic anhydride in the gas phase yielded difluorocyclopropenone in 21% isolated yield (eq 148). 234 This is an unstable cyclopropenone which decomposes at room temperature but can be stored for a long period of time at -78 °C. Fluorine is a strongly electronegative substituent, but it is also a π-electron donor.…”

Photodecarbonylation Mechanism of Cyclopropenone in the Gas Phase: Electronic Structure Calculation and AIMS Dynamics Simulation

“…Cyclopropenone (CP) is the simplest organic molecule that contains the conjugated CC and CO double bonds. Cyclopropenone and its derivative are molecules of great experimental and theoretical interests. − Cyclopropenone was first synthesized in 1967 and its properties were subsequently reported by Breslow and co-workers. ,,, Because of the conjugation interaction between the CC and CO bonds, cyclopropenone exhibits the aromatic character. , In comparison with cyclopropanone, cyclopropenone has higher thermal stability. However, cyclopropenone and its derivatives can dissociate into acetylene and carbon monoxide under relatively high temperature, which has been a subject of numerous experimental studies. ,,,,,, The key issue on the pyrolysis mechanism is whether the decarbonylation of cyclopropenones proceeds in a concerted or stepwise way.…”