L.".. I b-fts3 390 CONDUCTIVE MATERIALS BASED ON DELOCALIZED CARIANIONS V

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1 I b-fts3 390 CONDUCTIVE MATERIALS BASED ON DELOCALIZED CARIANIONS V 1 (U) PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF I MATERIALS SCIENCE AND ENGINEERING L F HANCOCK ET AL. UNCLSSIFIED 01 AUG 87 TR-5 MNM 4-65-K-0999 F/0 7/3 NL L."..

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3 OFFICE OF NAVAL RESEARCH iiftc;, fille,._cop D T IC o Contract N K-0899 ELECTE A UG 2 1 lgsz 0 ID R&T Code 1A:DHP ('f) Technical Report No. 5 (COD Conductive Materials Based On Delocalized Carbanions O~ by Lawrence F. Hancock and Bernard Gordon III Prepared for Publication in the ACS Division of Polymer Chemistry, Polymer Preprints Penn State University Polymer Science Section Materials Science and Engineering Department University Park, PA August 1, 1987 Reproduction in whole or part is permitted for any purpose of the United States Government This document has been approved for public release and sale; its distribution is unlimited. 04"

4 Unclassified SECURITY CLASSIFICATION OF THIS PAGE A D - 193a qo REPORT DOCUMENTATION PAGE l. REPORT SECURITY CL ASSIFICATION lb. RESTRICTIVE MARKINGS Unclassified NONE 2a. SECURITY CLASSIFICATION AUTHORITY 3. DISTRIBUTION IAVAILABILITY OF REPORT 2b. DECLASSIFICATION /DOWNGRADING SCHEDULE Approach Distribution for public release; unlimited 4. PERFORMING ORGANIZATION REPORT NUMBER(S) S. MONITORING ORGANIZATION REPORT NUMBER(S) Technical Report Number: 5 6a. NAME OF PERFORMING ORGANIZATION 6b. OFFICE SYMBOL 7a. NAME OF MONITORING ORGANIZATION The Pennsylvania State (if applicable) OFFICE OF NAVAL RESEARCH University 1 6c. ADDRESS (City, State, and ZIP Code) 7b. ADDRESS (City, State, and ZIP Code) University Park, PA Arlington, VA Ba. NAME OF FUNDING/SPONSORING 8b. OFFICE SYMBOL 9. PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER ORGANIZATION (If applicable) OFFICE OF NAVAL RESEARCH OW NOO14-85-K c. ADDRESS (City, State, and ZIP Code) 10. SOURCE OF FUNDING NUMBERS PROGRAM PROJECT TASK WORK UNIT ELEMENT NO, NO. NO. ACCESSION NO I1. TITLE (Include Security Classification) Conductive Materials Based on Delocalized Anions (unclassified) 12. PERSONAL AUTHOR(S) L. F. Hancock and B. Gordon III 13a. TYPE OF REPORT 113b. TIME COVERED 114. DATE OF REPORT (Year Month, 0ay) PAGE OUNT IFROM TO -1 8/1/ SUPPLEMENTARY NOTATION 17. COSATI CODES 18. SUBJECT TERMS (Continue on reverse if necessary and identify by block number) FIELD GROUP SUB-GROUP 19. FACT (Continue on reverse if necessary and identify by block number) Studies on the perparation of organic conductors based on delocalized carbanions are presented. The synthesis of sodium and potassium diphenylmethyl anions and potassium a..)'-diphenylxylenyl dianion. The anions were 1. characterized analysis of by protonated gas chromatographic quench produ.s. Preliminary DC conductivity measurements Sindciate a conductivity o 10xlO-18/cm for sodium diphenylmethyl anion. The synthesis of polyethers containing the diphenylmethyl structural unit are described. 20 DISTRIBUTION/AVAILABILITY OF ABSTRACT 21. ABSTRACT SECURITY CLASSIFICATION (3UNCLASSIFIED/UNLIMITED C SAME AS RPT C OTIC USERS Unclassified 22a NAME OF RESPONSIBLE INDIVIDUAL 22b TELEPHONE (Include Area Code) 22c OFFICE SYMBOL Dr. Kenneth J. Wynne ( 2 0 2) i I ONR h DD FORM 1473,84 MAR 83 APR edition rn.y be used until cxhausted. SECJRITY CLASSFICATION OF THS AGE All other editions are obsolete

5 CDiJVflVE MAIALS BASED ON DELOCAUM.M CARBANIONS ~ ~ ~ ~~ INTRODUCTION LwecF.Hancock. aid Bernard Gordon III PoyerSiec Section Penn State CM. Od University Putk, PA 16M0 ~J b J > C \ A ~. Organic mtraswhich possess metal-lke contluctviy have long been Synthesis of Dphenylanethozymethane (A) of interiest to chemists. Since 1977, when it was demonstrated diat polyacetylene on treatment with a variety of electron donors oraiposcud Diphenylhetoxymethene was prepared through a facile two step probe tinsformed from a semiconductor to a rottal-like coiductor! n cedure. First benzophenone was reduced with NaBH4 to benzhyrdrol. polymeric conductors has flourished. Wlihi this deluge a plethora of other Methylation was accomished with a Williamson reaction using DMS0 as polymers have been shown to be capable of metal-like conductivity upon the solvent, KOH as die base and MCI. 5 (Characterization of &~ bp 117- similartreatment. I H NMR M ; a5- I. IH; and 03.Z, 3H) Chemically, the transformation of a semiconductive, fully conjugated polymer (such as polyacetylene) to a metal-like conductor is believed to be a Sytthesi5 of K/Na Diplienylmethyl Anion (H) simple: electronic osidadion or reduction reacton. 2 The reductive process is shown schematically in Reaction!I for polyacetylene and an electron dono Diphenylmrethoxymethane was dissolved in hexane (0.2M); to thus mixas the dopmnt. The resulting electrically conductive material is apparently lutre a minimum of 5eq of the appropriate metal was added. The reaction based on an extended delocalized carbanionic: structural Unit. Our research was then stired under an inert atmosphere for 2-4 days. 'Me anions were is based on an alternative chemistry to an equivalent delocalized carbanionic formed assa fine Suspension in the inert Solvent. These were isolated via structure, as shown in reaction If. centrifugation and subsequently washed at least 2X with hexane. Thec anions were then dried to a fine powder on a high vacuum line. i. ~+29 Synthesis of axcs-dipleny-o.a-dimetlioxy-p-xylen (C) Compound.C was prepared in a two-step reaction procedure Initially. 212 equivalents of phenyl lithium was added to a THF solution of tereph- *thalaldehyde. The bis alkoxide formed by addition to the carbonyl moieties t was then methylated in situ with dimthylsulfale to form compound C (mp -2H C, IH NMR o7.3, 14H; a ; and a3.3, HH Synthesis of K aoa-diphenyl-p-xylenyl dianion () Proton abstraction from relatively acidic doubly allylic and/or benzylic Cmon 2wspeae ietyb h te laaerato hw methylene units is facile. The utility of strong base chemistry for the Cmpond xc as pr5epuiaently ptheiu by etl clasaed ation sown preparation of electrically conductive materials was first demonstrated abuove nes of Sr equiveaet ofe potumret was adred t or ays through the synthesis of poly(p-phenylene pentadienylene) and its 'doping" souonf idrcyohxe.temtuewstredartor2dy with n-ouli. 3 Tolbert et al. have also demonstrated proton abstraction at which lime the potassiumn dianion was isolated and washed with fresh doping for the preparation of doped polyacetylene. cylh~n through successive centfugation and decantation. In this work we would like to present further studies on die utility of proton abstraction doping for die preparation of organic conductors con- DISCUSSION centrating on die synthesis and properties of low molecular weight conductive anions. The aim of these studies is to lay the groundwork for the development of polymeric conductors based on delocalixed anions. Preparation of chemi- EXPERIMENTAL cally pure anions and characterization of their electrical properties are pivotal to die development of such a material. The ether cleavage reaction, dc- Synthetic schemes for the preparation of delocalized anions used in this scribed in bhexperimenta, provides a convenient route for the preparation study are outlined below, of chemically pure delocalized anions. Isolation of the anions is facilitated by precipitation from the hydrocarbon solvent; which are then easily dried under vacuum to arfie powder. Chemical purity of die anions was determined by both their reactivity (mecthylation with Mel) and through direct analysis of the quenched anion using capillary gas chromatography. Methylation of both the Na and K diphenylmnethyl anions provided 1..1-diphcnYlethanle.

6 me Structural confirmation of dbs polyether was obtuined ftmn IHi NMR. Gel pernuation chsluomtoaphy of dhe nuueral indiscated a polystyrene equiva- Shniairy. ofk ae-dphayxylnyldias whyatio yeldd cce. lent molecular weigbt of 2000nmA% Treatment of a TIF solution of the Sim~arl, Ka~adipuaylyleyl mehyldo.of danin 7addeabove polyether with n-dali yielded a deep blue solution, apparently imdidiphanyl-aadiemylityeme caing; anion formiation. However. the color bega to dissipate within Sfm, pemuably due to cleavag of tbs labile benal ether linkage. Our current synthetic target is compound L which should eliminate this Mel ~concern Capillary GC analysis was perfaumed on quenched sao*=e of the Na and K diphenylinethyl anions, Samples of dhe anions wen dissolved in. THF, quenched with t BuO*L then nenusihod. Me samples were analysed on a Hewlett.Pacluird 5M6 capillary gas chenstmogzapls using a 12 mete ACKNOWLEDGEMENT -nty siicons colom. No peaks wowe detct other than the -xece signals for the solvents (t~uoh azad 11fF) and diphenyietim The authos wish to thank the Office of Naval Research for their getter- Inisial studies on the electrical properties of the anions have been made ous support of this project. by 2pt and 4pt DC conductivity mieasuntsmts. Measuremuents have been perfonned using a Kieibly 617 elesnanmeam Kiethiy 124 curient source owd REFERENCES a Kiethly 197 nultineter. In miost cae measurenieats have been performed on pre-pressed pellets aof henions (samples went routinely 1) H. Shirjcawa. B.J. Louis, A. G. MacDiarmid and A. J. Heeger, J. pressed for 10-20mins at I0AOWKg~n 2 in a stainless steel K~r pellet Chan. Soc.. Cie. Comrman., 1977, 578. Press). 2) J. L Bredas, Rt. Rt. Chance and R. Sibley, Phys. Rev. B Results obtained for the Na diphenylmethyl anion tesed insa linesr 4pt geomectry showed a conducitivity of SxilO 4 Skna However, a this point 3) L F. Hancock. B. Hilker, W. Chapoian and B. Gordon Ill, Polymer the affect of a minute aniount of residual Na metal has not been discerned. Pr'eprints. 156G. 27(1), 359; L F. Hancock and B. Gordons 111, Podymer The K diphenylmethyl anion exhibited a more complex behavior. I (in press). Prepressed pellets of the anion wene very raistive(>gq). However under 4) L M. Tolbert and J. A. Schomaker, Polyher Prepriwt (2). a pressure of 2AEIOKS~ 2 resistivides as low as 1015KW have been noted A more detaildd evaluation of this behavior is being uadenaken. 5.A.JhsoeadM.Rw eaern Preparation of polymer supported delocalized anions is proceling 5)RA.W osieadm..rs.terido,1793,26. concurrently with our studies of isolated anions. A Wiliamson ether condensation polymerization has been utilized for the preparation of a polyether possessing a diphenylmethyl structural unit (shown below). CICH-(Q OJI -C + -0 HD- * -CHAcceion Fur I 140H NTIS CRAq&I H -%l ETiC TAB L] 2' B y Di! no-'z 1

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