Properties of tetramethyleneethane (TME) as revealed by ion chemistry and ion photoelectron spectroscopy

The negative ion chemistry and photoelectron spectra of[CH2=C(CH3)-C(CH2)2]- and [(CH2)2C-C(CH2)2]- have been studied. The negative ion photoelectron spectra reveal the tetramethyleneethane diradical, TME, to have two low-lying electronic states, X̃ and ã. The ground X̃ state is assigned as [TME] 1A and the excited ã state as [TME] 3B1. The energy separation between these states is about 2 kcal mol-1; ΔE[ã 3B1 ← X̃1A] ≅ 0.1 eV. The experimental electron affinities of the neutrals are: Eea[CH2=C(CH3)-C(CH2)2] = 0.654 ± 0.010 eV and Eea[(CH2)2C-C(CH2)2] = 0.855 ± 0.010 eV. The experimental gas phase acidities are: ΔacidH298[CH2=C(CH3)-C(CH 2)CH2-H] = 388 ± 3 kcal mol-1 and ΔacidH298[(CH2)2C-C(CH 2)-CH2-H] = 388 ± 4 kcal mol-1. These findings can be used to establish the bond energies and heats of formation: DH298[CH2=C(CH3)-C(CH2)CH 2-H] = 90 ± 3 kcal mol-1 and ΔfH298[(CH2)2C-C(CH 3)=CH2] = 48 ± 3 kcal mol-1; DH298[(CH2)2C-C(CH2)CH 2-H] = 94 ± 4 kcal mol-1 and ΔfH298[(CH2)2C-C(CH 2)2] = 90 ± 5 kcal mol-1

Anion recognition by azophenol thiourea-based chromogenic sensors: A combined DFT and molecular dynamics investigation

10.1007/s00894-012-1530-0Journal of Molecular Modeling191205-213JMMO

Neural Mechanisms of Encoding Binaural Localization Cues in the Auditory Brainstem

When an animal hears a sound in its environment, there are several important tasks that the auditory system must try to accomplish. Two major jobs are to determine what it was that produced the sound and where it comes from. Understanding how the nervous system can accomplish these tasks is a majo