Ouroboros: Heterocycles closed by dative σ bonds and stabilized by π delocalization

Charge density of 4-methyl-3-[(tetrahydro-2H-pyran-2-yl)oxy]thiazole-2(3H)-thione. A comprehensive multipole refinement, maximum entropy method and density functional theory study

“…8(b) and 8(c). This resembles more dative -bonding as described by Donald et al (2019) for B N bonding between the terminal N and B atoms. Thus, one may point out that such a spatial arrangement around the negatively charged nitrogen and oxygen atoms is not consistent with a covalent bond.…”

Resonance-assisted intramolecular triel bonds

“…NICS(1) zz was evaluated as the chemical shielding at a point lying 1.0 Å above the ring center, defined as the z direction of the heavy atom coordinates. 54,55 A combination of NBO5.0 56 and Multiwfn 57 programs can provide information for normalized multicenter bond order, which is also used to estimate the aromaticity. 58…”

“…It has been found that best results are often achieved in evaluating the z-component of this property 1 Å above the ring center, commonly referred to as NICS(1) zz , and a more negative value is an indication of greater aromaticity via its ring current. 54,55,[69][70][71] This index is reported in Table 5 for the various systems considered here. Note first the large jump on going from the first to the second row where the conjugation has been introduced.…”

Twenty years of exceptional success: The molecular education and research consortium in undergraduate computational chemistry (MERCURY)

“…The faculty published 2 peer‐reviewed books, [ 238,239 ] 9 peer‐reviewed book chapters, [ 240–248 ] and 115 peer‐reviewed research papers. [ 249–363 ] This comes to 1.6 peer‐reviewed products/faculty/year during the 3‐year grant period, which is 3.2 times the rate of publication for natural science faculty at PUIs. [ 46 ]…”

“…Kelling Donald's research: In the Donald research group, work is focused on (a) halogen bonding and other sigma hole interactions in organic and inorganic systems, [ 210,278 ] (b) fluxionality in planar inorganic clusters and the nature and potential control of so‐called molecular machines, [ 208,263 ] (c) the evolution of structural preferences and thermal stability in metal halide and hydride molecules, clusters, and corresponding extended solids, [ 322 ] (d) the stability and catalytic applications of structurally interesting or unusual main‐group and transition‐metal organometallic compounds, [ 151,231,351,385 ] (e) the stabilization of unusual bonding arrangements, including planar tetra‐coordinate and other unusual coordination environments, [ 172 ] (f) quantifying currently qualitative but transferrable concepts in chemical bonding, [ 233 ] and (g) aromaticity and analogous phenomena in non‐hydrocarbon systems. [ 338,386 ] The MRI resources are essential for calculations on large and heavy elemental systems.…”