Circumambulatory rearrangements of cyclopolyenes containing element-centred migrants

Abstract

PACS. 73.20.At -Surface states, band structure, electron density of states. PACS. 73.23.Ad -Ballistic transport. PACS. 73.50.-h -Electronic transport phenomena in thin films.Abstract. -We present fully quantum-mechanical magnetotransport calculations for shortperiod lateral superlattices with one-dimensional electrostatic modulation. A non-perturbative treatment of both magnetic field and modulation potential proves to be necessary to reproduce novel quantum oscillations in the magnetoresistance found in recent experiments in the resistance component parallel to the modulation potential. In addition, we predict oscillations of opposite phase in the resistance component perpendicular to the modulation not yet observed experimentally. We show that the new oscillations originate from the magnetic miniband structure in the regime of overlapping minibands.

Barriers to the intramolecular N‐ to N‐transfer of different groups in pyrazoles: Prototropy vs. Elementotropy

“…• , thus an increase in θ means that the MH 2 group rotates more in BH 2 rearrangements of cyclopentadiene derivatives CpM [42,43]. With the following values in kJ mol −1 of 98.7 (H), 56.9 (Si), 51.9 (Ge), 31.4 (Sn), and 58.2 (B) [41], Eq.…”

A Cationic Phosphapyramidane

“…[8] Amazingly,d espite its anticipated C S -symmetry [for the optimizedg eometry of 1,s ee Figure S6 29 Si NMR (À8.9), 31 PNMR (À158.9) (Supporting Information, Figures S1-S4). [9,10] In accord with this hypothesis, the calculated barrier to migration was only 12.8 and 15.2 kcal mol À1 for the H-substituted model (at B3LYP/Def2TZVP [DFT1] and M06/6-311 + G(d,p) [DFT2],r espectively,s ee Figure1)a nd even 10.5 kcal mol À1 for the H 3 Sisubstituted model (at DFT1, Figure 1), which values are quite reasonable even considering ar oom temperature process. [9,10] In accord with this hypothesis, the calculated barrier to migration was only 12.8 and 15.2 kcal mol À1 for the H-substituted model (at B3LYP/Def2TZVP [DFT1] and M06/6-311 + G(d,p) [DFT2],r espectively,s ee Figure1)a nd even 10.5 kcal mol À1 for the H 3 Sisubstituted model (at DFT1, Figure 1), which values are quite reasonable even considering ar oom temperature process.…”

Stereochemical Nonrigidity of Organometallic Complexes

“…105 Since the rhenium fragment is chiral diastereomers are formed with prochiral olefins; hence, rotamers interconvert faster than diastereomers. The interconversions of rotamers for propene are shown in Figure 4; diastereomer interconversions involve barriers of ∼134 kJ mol The TpRe(CO)(PMe 3 )(thiophene) complex shows a selectivity of 3.2:2.0:1.0 for diastereomer (22) to (23) to an η 1 -S isomer, as shown in Figure 5. This complex, as well as other thiophene complexes, offer the potential for an intramolecular face flip via formation of an η 1 -S intermediate that could invert at sulfur to interconvert diastereomers.…”