Herein, the supramolecular architectures sustained by secondary bonding, encompassing tetrel, pnictogen and chalcogen bonding, interactions occurring between metal centres, metal⋯hydrogen, metal⋯π, main group element(lone pair)⋯π, and finally, those involving chelate rings sustained by formal bonding or by hydrogen bonding are described.
They are classified as bicyclic, tricyclic, tetracyclic, and so forth, according to the number of formal bond disconnections necessary to produce a noncyclic carbon chain.
Third, although Rome did not seek to govern Italy through a regular administration, it influenced local affairs through formal bonds of personal friendship (amicitia) and hospitality (hospitium) between the Roman elite and their local counterparts.
Connectivity (no formal bond orders) a. disconnected metals b.
For example, the computational solids group (CMLComp) insisted that a molecule should not contain bonds as they did not exist, whereas the chemical informatics community is concerned not only that bonds should exist but that they should be annotated with their formal bond order.
For atoms within the same molecule that are close in space, but not linked through a direct formal bond, the question arises, how much of the observed coupling is transmitted through a succession of bonds that eventually links them ("through-bond coupling"), and how much is due to interaction through the overlap of lone pairs ("through-space coupling").
In alternating single/double bond cyclic systems, bond-finding algorithms determine whether a formal double bond can exist between each of the two attached atoms.
It proceeds in two stages, the first of which is an elimination in which a formal triple bond is incorporated into the ring to give a benzyne intermediate.
analysis and by theoretical calculations that free rotation around formal single bonds is hampered by conjugation.
When using input originating from drawings, the perception of formal double bonds capable of supporting Z/E isomerism (Table 3) relies on atomic coordinates.
Efforts to tackle low permeability and high efflux in our previously reported pyrrolopyrimidine series (Scott et al., 2017) led to the identification of pyrrolotriazines which contained one less formal hydrogen bond donor and were intrinsically more lipophilic.
