Part 2 Flashcards
Spectrometer placed where in flow when oxygen used?
before oxygen added as air bubbles will disrupt in-line monitoring
reduce reaction time in flow
increasing pressure gives higher solvent boiling points and quicker reactions, increasing temp generally increases reaction time, flow also has more efficient heat transfer allowing for faster interception of potentially unstable intermediates
non-radiative processes
inter-system crossing, internal conversion
radiative processes
fluorescence and phosphorescence
consequences of high quantum yield of radiative processes for photoexcitation of O2
low excitation of O2 as these compete with triplet-triplet anhiliation
wavelength for photodynamic cancer therapy
UV is damaging, ideally 600-800 nm but longer wavelengths aren’t effective for photoexcitation of O2
test reaction for singlet O2 production
a-terpinine to ascaridole
test if superoxide is produced in reaction
superoxide is a radical, radical trapping experiments eg with TEMPO
Heck
alkyl halide with alkene using Pd(0) and base
Stille
alkyl halide with Sn(Me)3-R using Pd(0)
Suzuki
R-B(OH)2 with alkyl halide using Pd(0)
Sonogashira
alkyl halide and alkyne with Pd(0), CuI and EtNH2
conjugated microporous polymers characteristics
3D networks, cross-linked, conjugated throughout
CMP design
building blocks must have at least two reactive groups, for 3D structure need cross coupling of building blocks with different geometries
disadvantages of CMPs
insoluble therefore exist in solns as dispersion/suspension, need specialist peristaltic pump in flow and solid may block in-line monitoring techniques
CMP vs cross-linked polymers
CMP need continuous pi-conjugation throughout but cross-linked polymers don’t and both utilise cross-coupling reactions for their formation
merrifield resins
insoluble polymeric support for photocatalysts
advantages of Merrifield resins
immobilise photocatalyst in given flow path allowing for easy recovery and less product purification steps
formation of merrifield resins
coupling reactions
characterising photoelectronic properties
UV vis for which wavelength a photocatalyst absorbs at, fluorescence quantum yield as if too high it’s not a good photocatalyst as this competes with ISC and cyclic voltrametry to measure redox potentials and tell us size of HOMO-LUMO gap
requirements for free-radical polymerisation
initiator AIBN, main monomer, bifunctionalised cross linker and molecule with required FG
