Macromolecules 2003, 36,

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1 Cyclic AFT/MADIX CT Agets by obert B. Logi rlogicosultig.com Cyclic AFT CTA's ca polymerize viyl moomers ito cyclic polymers. Cyclic polymers because of their uique properties compared to their liear couterparts iclude reduced hydrodyamic volume, lower itrisic viscosity ad distictive fluorescece ehacemet, higher Tg, higher refractive idex. Cyclic polymers exhibit edless topologically with more striget restrictios o the backboe coformatio ad the absece of chai eds (JUNAL F PLYME CIENCE, PAT A: PLYME CHEMITY 2016, 54, ). Macromolecules 2003, 36,

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3 Moad et. al. Aust. J. Chem. 2009, 62, The above were really the few refereces I foud for AFT rig expasio polymerizatio(ep). They appear to require a macrocycle CTA so that rig strai is ot

4 a factor or ca rig strai ehace the polymerizatio? To explai my ideas the followig figures are referred to: ythesis of the 4,5-Dipheyl-1,3-oxathiolae-2-thioe moomer i 86% yield: I. Yavari - Me C 2 " Base + + Pheyl derivatives are show but other derivatives are possible X Y

5 et. al. ylett 2008(6), The facile reactio of C2 with epoxides is the reaso I'm iterested i this xathate's MADIX potetial. The reaso for the 1,2 epoxy derivative is that the reactio affords the uwated isomer (5 positio) if a moo-substituted epoxide is employed (ther sythesis routes could be proposed that would afford the moo derivative attached to the 4-carbo ext to sulfur). This 4 substituet however must be capable of stabilizig radicals that are reactive eough to start the MADIX polymerizatio. The bezyl group is kow to do this. The iitial small amout of added iitiator adds to the 2-thioe group, the geerates the carbo radical stabilized by the bezyl group(hog et. al. show above is a example). More detailed explaatio of AFT/MADIX ca be foud i several reviews such as D.J. Kiddie et. al. Macromol. 2012, 45, efereces for Xathate sythesis: N. Kihara et. al. JC 1995, 60, Maggi et. al. ythesis 2008(1), W. Clegg et. al. JC 2010, 75, Y. Taguchi et. al. Bull. oc. Jp., 61, (1988). W. Choi et. al. Macromolecules, 1998, 31, My idea is to use this type of cyclic xathates i AFT/MADIX CTA polymerizatio. With the above CTA's, the polymerizatio could possibly go two ways; cyclic formatio of a macrocyclic or a cyclicpolymer cotaiig multiple xathate moieties. X ad Y are attached i a very large macrocycle. ca be from the various moomers such as NVP, Vac, MA, MMA etc. that could be employed i this polymerizatio. What follows is what should be a example of this idea.

6 Macromolecular apid Commuicatios; oriao-moro et. al. I do't uderstad why the bezyl group does't stabilize the carbo radical? ly 4 refereces cited this referece, idicatig to me that the above iterpretatio of the reactio was ot of iterest or valid. If their iterpretatio is correct the they would have to idicate what's at the other ed of the polystyree? The termial of the polymer would be hard to distiguish with all the styree pheyls if ideed it was a bezyl i possibly a cyclic motif? ice o attempt to try this CTA with MMA etc. which would clearly show the termial moiety if it was bezyl; therefore, I believe my iterpretatio is valid. However their sythesis of the dithiolactoe itself is useful. Here's what the experts say! Aust. J. Chem. 2009, 62, The thiolactoe 19 was proposed to cotrol the polymerizatio of t by a similar additio fragmetatio process (cheme 2).[83] The mechaism as show seems ulikely sice, for cotrol, most of the propagatig species would eed to be preset as

7 the dormat species 21. E experimets showed that a high cocetratio of radicals were ot preset durig polymerizatio. The mechaism would suggest that the fial product should also have structure 21. Clearly this is ot the case. Numerous refereces clearly show the geeratio ad stability of the bezyl's group's iteractio with the carbo radical ad its ability to start the MADIX polymerizatio, the same mechaism should be at play here also. Livig Catioic Cyclic Polymerizatio ecetly several very iterestig papers have appeared cocerig the applicatio of AFT CTA's that work with catioic CLP. With the AFT aget, block polymers of viyl ethers are easily sythesized, ot oly that but catioic followed by CP polymerizatio is possible.

8 Although these papers illustrate how selected AFT CTA's ca be used, I could ot fid ay example of their use to form cyclic polymers of viyl ethers. Cosiderig my previous paper cocerig cyclic AFT CTA's, it would seem obvious that or similar AFT CTA's would result i well cotrolled catioic cyclic polymerizatio. I ca visualize several iterestig applicatios for cyclic catioic polymerizatio. I aalogy with the crow ethers, cyclic methyl viyl ether or other VE's or mixtures or CP followig catioic ca all be accomplished with AFT/MADIX CTA's. uch large macrocycles havig ether groups, for example, projectig i or out of the cyclic chai would have uusual complexig behavior. Coductig said catioic polymerizatio i the presece of a complexig aget should cotrol orietatio of the ether groups much like a catio cotrols the preparatio of crow ethers. VE VE H + H H ather tha draw all AFT/MADIX CTA possibilities, the above are suggested.

9 Cyclic catioic polymerizatio followed by CP would afford copolymers of MVE ad NVP for example (may moomer combiatios are obviously possible), that would lead to cyclics exhibitig uique complexig ability. Fluorie derivatives might eve have use as blood substitutes. I hope you foud these proposals iterestig. Thaks for readig! Dr. obert B. Logi, rlogicosultig.com