Photoelectron spectroscopy carbenes from

Cyclopent-2-en-l-one, 2-hydroxy-3-methyl-synthesis, 3, 693 Cyclopentenone, 4-methoxy-formation, 1, 423 Cyclopenthiazide as diuretic, 1, 174 Cyclopent[2,3-d]isoxazol-4-one structure, 6, 975 Cyclophane conformation, 2, 115 photoelectron spectroscopy, 2, 140 [2,2]Cyclophane conformation, 2, 115 Cyclophanes nomenclature, 1, 27 Cyclophosphamide as pharmaceutical, 1, 157 reviews, 1, 496 Cyclopiloselloidin synthesis, 3, 743 Cyclopolymerization heterocycle-forming, 1, 292-293 6H-Cyclopropa[5a,6a]pyrazolo[l,5-a]pyrimidine pyrazoles from, 5, 285 Cydopropabenzopyran synthesis, 3, 700 Cyclopropachromenes synthesis, 3, 671 Cyclopropa[c]dnnolines synthesis, 7, 597 Cyclopropanation by carbenes... 

The electronic structures of the l,3,2(A2)-diazasiloles 83-85 and 89 have been probed by He(i) and He(n) photoelectron spectroscopy. The experimental ionization potentials are summarized in Table 3. The molecular orbitals were assigned with the help of quantum mechanical computations for model compounds and in each case the HOMO was found to be a Jt-type MO of b, symmetry. In the case of the benzol] and pyiido[/4 fused compounds 85 and 89 also the HOMO-1 is a Jt-type MO. The next band was assigned to a lone pair-type MO of aj symmetry, which is mostly located at the dicoordinated silicon atom. Therefore, the HOMOs of the cyclic silylenes 83 and 84 differ in nature from those of the homologues V-heterocyclic carbenes which consist of an essentially aj lone pair-type MO at... 

Clauberg, H. Minsek, D. W. Chen, P. Mass and photoelectron spectroscopy of CjHj. AHf of singlet carbenes deviate from additivity by their singlet-triplet gaps, J. Am. Chem. Soc. 1992,114,99-107. 

Considering the observations that vaporized ILs [105] consist of single ion pairs [106-108], these aforementioned gas phase calculations on these structures directly represent the vapor of ILs. Thus, photoelectron and mass spectroscopies could be applied to confirm directly the results of the theoretical calculations [30]. Interestingly, under the conditions of photoelectron spectroscopy (ca. 10 mbar, 420 K), the first reported isomer B carbene-acetic acid H-bonded system - and not the ion pair A - has been observed [30], in contrast to previous findings for ILs, containing less basic anions [105-108]. This result indicates that the stability of isomer A is slightly overestimated by some of the theoretical methods applied. A further important observation for the vapor phase structure comes from the MS spectmm, which clearly shows all the characteristic peaks of acetic acid (base peak at... 

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