hatcher content part 3

what is edge directed assembly?

precursors whose chemical components will lie upon and define the edges of the desired ring or cage are employed

angles between reactive sites on the building blocks are retained in the final structure and closely match the ideal values for the preferred product

what is face directed self assembly?

some or all of the faces of the target aggregate are spanned by the linkers themselves which hold together the overall architecture

how important are guest molecules in forming complexes?

some will only form in high yield when a specific guest is used

the size of the hydrophobic moiety and the charge of the guest species all play a role

the guest induces the organisation of its own receptor

how can you remove an anionic guest from a Pt(II) framework?

Pt-N bonds are irreversible, so guest removal wont result in cage collapse

acidification will protonate the anionic guest so that it exits the cavity due to cationic repulsion

adding base again will return the guest to the cage due to decreased hydrophobic effects

how can cages be used to for stereoselectivity of alkenes?

under normal conditions the trans isomer may be favoured

make a cage where it wont fit so that the cis isomer is favoured

pr do this the ither way around

what interactions can anions form with pyridine?

arimatic pi pi stacking

determine with x ray structure

what types of aromatic interactions are there?

face to face (staggered for attractive interactions)

edge to face where the hydrogens come in towards the other ring center

how can you determine if a guest moves within a cavity?

need an aymmetric guest

variable temp 1H NMR in D2O for a 1:1 mixture of guest snd host

measure the coalescence temp

if observed, the guest is escaping from the tube leading to symmetrisation

what are the two exchange mechanism possibilities?

when guest:tube ratio </= 1.0, the guest must leave the tube prior to flipping and reentering

a pseudo sn1 like mechanism

when guest:tube ratio is >/= 1.0, the incoming guest can enter as the outgoing guest leaves

a speudo sn2 like mechanism

how can guests be removed from nanotubes?

protonation of the carboxylate

extraction with a non-polar solvent (for neutral guests)

unless yhe solvent is sufficiently stabilising, tubes often collapse

can be stabilised by increasing the tube length - increasing the number of irreversible Pd-N interactions