Cyclodextrins! A powerpoint presentation :evening Presenting-Addison Carter Advisor- Dr David Kammler

Cyclodextrins: α-cyclodextrin- 5 sugar molecules β-cyclo-dextrin- 6 sugar molecules γ-cyclodextrin- 7 sugar molecules Simply cyclized α-d-1,4-glucopyranose sugar

Utility to Humans Centered in the Torus shaped form, differing interior sizes allow for encapsulation of many target compounds. β-cyclo-dextrin

Nonpolar central cavity Secondary Hydroxyl rim Primary Hydroxyl Rim An ether-like central section creates ideal conditions for preferential spacial arrangement of non-polar compounds in the central section The exterior wall retains polar (hydrophilic) sugar-like character which allows for solubility of the cyclodextrin molecule both with and without a guest molecule

Bacillus Circulans Cyclodextrin glucosyltransferase- Extracted v. in situ In reaction vats at pH at °C. The source of cyclodextrins Within starch producing plants

Targets:

Real World Apps Drugs -solubility -photostability -oxidation prevention -ease of handling Synthesis -site-selective binding -chiral selectivity -general protecting group

Real World Apps II Environmental Problems -well water contamination -hypothetically use for heavy metal contamination Chemical Analysis with HPLC -selective complexation with different target substrates allows for different flow rates for the various target substrates Enzyme Mimicry?

Polymerization Terephthalic acid polymerization Methyl Methacrylate Polymerization

Phase Typed Polymerization Bulk Solution Emulsion Dispersion One Phase Two Phase

Trouble with polymerization Surfactants -used in emulsion polymerization, one of the main modes of plastic production -phosphate/sulphate anion base The problem: Not many readily available natural break down paths

Alternative Mode to Emulsion Polymerization Dispersion Polymerization: Non-polarPolar Some small number of monomeric units move into the aqueous phase to be polymerized. -rate -polydispersity -phase separation Essentially this is the question of how much monomer will transverse the interstitial zone between the oil and water layers

A Potential Solution: Cyclodextrins as Phase Transfer Agents Non-Polar Polar Complexation Polymerization Initiator In this the cyclodextrin modulates the transverse activity of the monomer.

So then, what's the next Question, Considering: -dispersion polymerization is well documented -with many substrates -in many solvent pairs -with some phase transfer catalysts -only one person will be working on this project as a four credit class over the course of a semester -numbers on the equilibria of substrates/substrate-cyclodextrin pairs is not readily available -we do not have an NMR available to examine complexation however, -we do have a Ultraviolet-Visible spectrophotometric machine -cyclodextrin doesn't absorb UV-Vis spectrum light

Thus, -We can find concentrations of photo responsive chemicals in solution -in the aqueous layer (as well as the organic layer) with and without Cyclodextrin for each of our target molecules -partition coefficients for those solvated chemicals Absorption Molar Absorption Constant Length of Absorbing sample Concentration of absorbing sample

Substrate Choice - UV-active - polymerizable - soluble - complexable - available from the local stock of chemicals All these are either mono- or di- substituted benzene rings which are known to be quite UV-active. They are also cheap and polymerizable Styrene Terephthalic acid p-aminobenzoic acid p-pentylstyrene

Para-amino benzoic acid(PABA) -Locally available -PABA is very UV active -soluble in water -soluble in ethyl acetate The problem -Too UV active in Ether, Ethyl Acetate, Water, 1-Octanol.1 M?.01 M?.001 M?.0001 M? Dilution to this level allowed for a scale within machine detection limits. - Not an effective use of time considering the interest was to study partitioning with an eye toward polymerization which would be served via other routes

Terephthalic Acid, the First alternate Problem:Solubility.1 M.01 M.001 M Styrene, the Second Alternative Unfortunately past this molarity the accuracy of the scale would be called into question for the amount of solvent that was acceptable. Problem: Time -Only preliminary testing at.01 M was conducted however absorbance was within the detection envelope for the instrument. -Much lower prep time would result in larger volume of data

AKA: The 1.5 month time warp An Interlude Concerning the Repair of a Certain Piece of Instrumentation Vital! to the Continuation of Senior Project

Epsilon Values of PABA in Four Solvents Determined at.0001M PABA in named solvent E In Ether E E E In Ethyl Acetate In Water In 1-octanol at 275 nm at 284 nm at 275 nm at 266 nm Values taken at the most convenient location along the graph of absorptivity, λ max.

Partitioning Behavior Compared With and without cyclodextrin.264 at 273nm.268 at 273nm 1 M equivalent CD

Amount of Cyclodextrin the issue?.202 at 276nm 10 Molar equivalents of cyclodextrin present yields lower absorbance than the previous 1 Molar equivalent system -instead of complexing with the PABA the peak shifting right may be a sign of ethyl acetate complexation

The Road from here: Choice in substrate -late found resources have recipes in which pure substrate is used as the non-polar phase example:styrene ON aqueous cyclodextrin mixed -mono-substituted benzene rings -biphenyl Time to mix -late found materials point to time scale of days for complexation Substituted cyclodextrin -better match