Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1964 Preparation and stability of phenylated polysilanes Gerald Lee Schwebke Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Organic Chemistry Commons Recommended Citation Schwebke, Gerald Lee, "Preparation and stability of phenylated polysilanes " (1964). Retrospective Theses and Dissertations. 3008. https://lib.dr.iastate.edu/rtd/3008 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. This dissertation has been 64—9285 microfilmed exactly as received SCHWEBKE, Gerald Lee, 1937- PREPARATION AND STABILITY OF PHENYLATED PO LYSILANES. Iowa State University of Science and Technology Ph.D., 1964 Chemistry, organic University Microfilms, Inc., Ann Arbor, Michigan PREPARATION AND STABILITY OF PHENYLATED POLYSILANES by Gerald Lee Schwebke A Dissertation Submitted to the Graduate Faculty in Partial Fulfillment of The Requirements for the Degree of DOCTOR OF PHILOSOPHY Major Subject: Organic Chemistry Approved: Signature was redacted for privacy. In Change of Major Work Signature was redacted for privacy. Signature was redacted for privacy. Iowa State University Of Science and Technology Ames, Iowa 1964 il TABLE OF CONTENTS INTRODUCTION NOMENCLATURE HISTORICAL Polysilanes Structure and Properties of the Cyclosilanes Chemistry of the Silicon-Silicon Bond Derivatives of Octaphenylcyclotetrasilane Polysilanes Derived from Decaphenylcyclo- pentasilane EXPERIMENTAL Stability of Alkyllithium Compounds in Mixed Solvent Systems Preparation of n-butyllithium in diethyl ether Preparation of n-decyllithium and n-tetradecyllithium in diethyl ether Preparation of n-decyllithium. in tetrahydrofuran (attempted) Relative stabilities of n-butyllithium in ether-tetrahydrofuran, ether- tetrahydropyran, and ether-2,2,4,4- tetramethyltetrahydrofuran Decomposition of n-butyllithium in ether-tetrahydrofuran Decomposition of n-tetradecyllithium in ether-tetrahydrofuran Decomposition of n-decyllithium in ether-tetrahydrofuran Relative stability of n-decyllithium in mixed solvents Stability of n-decyllithium in diethyl ether Derivatization of n-decyllithium in ether-tetrahydropyran ill Page Derivatization of n-decyllithium in ether-2,2,4,4-tetramethyltetrahydrofuran 48 Preparation of n-de cyltriphenylsilane 49 Preparation and Reactions of Benzyllithium 50 Benzyllithium from benzyl methyl ether 50 Benzyllithium from benzyl ethyl ether 51 Cleavage of hexaphenyldisilane with benzyllithium 53 Run 1 53 Run 2 54 Run 3 55 Preparation of Phenylated Cyclosilanes 55 Octaphenylcyclotetrasilane 55 Decaphenylcyclopentasilane 56 Compound C 58 Purification of Compound C 59 Dodecaphenylcyclohexasilane 6l From dichlorodiphenylsilane and 1,5-dilithiodecaphenylpentasilane 61 From 1,3-dichlorohexaphenyltrisilane and sodium 62 From 1,3-di chlorohexaphenyltri silane and magnesium 63 From 1,3-dihalohexaphenyltrisilane and sodium-potassium alloy 63 Tetradecaphenylcycloheptasilane (attempted) 65 Reaction of dlchlorodimethylsllane with lithium 65 Derivatives of Octaphenylcyclotetrasilane 67 Octaphenylcyclotetrasilane with. anhydrous hydrogen bromide 67 Octaphenylcyclotetrasilane with anhydrous hydrogen iodide 68 Octaphenylcyclotetrasilane with anhydrous hydrogen chloride 69 1,2-Dibromotetraphenyldisilane 70 iv Page 1,4-Dibromooctaphenyltetrasilane 71 n-Decyllithium with lH-4-bromoocta- phenyltetrasilane " 71 n-Decylmagnesium bromide with lH-4-bromooctaphenyltetrasilane 73 n-De cyl lithium with 1,4-dichloro- octaphenyltetrasilane 74 n-Decyllithium with 1H-4-chloro- octaphenyltetrasilane 74 1.4-Di-n-butvloctaphenyltetrasilane (attempted) 76 Derivatives of Decaphenylcyclopentasilane 76• 1.5-Dibromodecaphenylpentasilane 76 From decaphenylcyclopentasilane and bromine 76 From 1H,5H-decaphenylpentasilane and phosphorus pentabromide 77 1H,5H-Decaphenylpentasilane 78 lH-5-Bromodecaphenylpentasilane (attempted) 78 lH-5-Chlorodecaphenylpentasilane (attempted) 79 1,5-Dibromodecaphenylpentasilane with n-de cylmagne sium bromide in tetrahydro­ furan 80 De c aphenyIpenta silane-1,5-dio1 8l 1H,3H-Hexaphenyltrisilane 8l 1H,3H-Hexaphenyltrisilane with N-bromo- succinimide in carbon tetrachloride 82 1,3-Dibromohexaphenyltrisilane 83 1,5-Dilithiodecaphenylpentasilane • 84 1,5-Di-n-butylde caphenylpentasilane 85 1,2-Di-n-butyltetraphenyldisilane 86 1,5-Dime thyIdeeaphenylpentasilane 87 From 1,5-dilithiodecaphenylpentasilane and trimethyl phosphate 87 From 1,5-dibromo de c aphenylp enta si1ane and methylmagnesium iodide 88 From l-lithio-2-methyltetraphenyl- disilane and dichlorodiphenylsilane 89 V Page 1,1,1,7,7,7-Hexamethyldecaphenylheptasilane 90 1H,7H-Tetradecaphenylheptasilane 90 1,1-Dimethylde caphenylcyclohexa silane 91 Decaphenylcyclopentasilane with lithium in the presence of chlorotrimethylsilane 93 Reactions of Compound C 95 Lithium cleavage of Compound C 95 Reaction with trimethyl phosphate 95 Reaction with tri-n-butyl phosphate 96 Short contact time followed by trimethyl phosphate 97 Short contact time followed by tri-n-butyl phosphate 99 Compound C with phosphorus pentachloride in sym-tetrachloroethane 101 Compound C with mercuric chloride 102 In benzene 102 In tetrahydrofuran 102 Compound C with chlorine 102 Compound C with bromine 103 Compound C with methyllithium 103 Compound C with benzyllithium 104 DISCUSSION 105 Stability of Some n-Aikyllithium Compounds in Mixed Solvent Systems 105 Preparation and Some Reaction of Benzyllithium 111 Formation of the Phenylated Cyclosilanes 115 Some Reactions and Derivatives of Octaphenylcyclotetrasilane 132 Derivatives of Decaphenylcyclopentasilane 142 Reactions of Compound C 151 vi Page Tabulation of Organopolysilanes 155 Suggestions for Further Research 162 SUMMARY • 164 LITERATURE CITED • 169 ACKNOWLEDGMENTS 177 1 INTRODUCTION Interest in polysilane compounds stems from the possibility of using the silicon chain as the backbone of potentially useful polymers. Misconceptions based on observations on unsubstituted polysilanes have arisen concerning the relative stability of such compounds as a function'of the silicon chain length. Appropriately sub­ stituted polysilanes, however, should possess a greater degree of stability and the paucity of such compounds can be laid rather to problems in methods of preparation. Therefore, the purpose of the work presented here was to investigate methods of preparation of organically sub­ stituted polysilanes, more particularly, phenyl substituted compounds having silicon functional moieties in terminal positions. Entrance into the area of phenyl substituted poly­ silanes is most easily gained through the perphenylated cyclosilanes, initially studied by F. S. Kipping and his co-workers in the decade following 1920. These compounds have been subject to considerable investigation and de­ liberation concerning their constitution and structure, both by Kipping and by workers in These Laboratories. Particular emphasis has been placed on the compound, decaphenylcyclopentasilane, in confirming its structure 2 and in investigating its derivatives as intermediates in the synthesis of other polysilanes. NOMENCLATURE In naming organosilicon compounds having silicon chains, the rules of nomenclature recommended by the Commission of Nomenclature of Organic Chemistry of the I.U.P.A.C., and adopted by the American Chemical Society (l), will be used with thé exceptions noted below. Organosilicon compounds having open silicon atom chains will be named as derivatives of compounds of the general formula H^Si(SiHg)^SiH^ and will be called disilanes, trisilanes, tetrasilanes, etc. The generic name of such compounds is silanes. For designating the position of substituents in compounds named as silanes, each member will be numbered from one terminal silicon atom to the other. Because the compounds discussed here are highly substituted straight-chain silanes bearing generally the same organic substituents on each silicon atom, with vary­ ing terminal groups, the position of these organic sub­ stituent s will not be numbered in order to avoid unwieldy sequences of numbers. Therefore, the compound of the 1 formula BrSiPhg(SiPh2)^SiPhgBr will be named 1The abbreviation Ph for the phenyl (C5H5) group will be used throughout this thesis. All other groups will be designated by their structural formulas. 4 1,5-dibromodecaphenylpentasilane, instead of 1,5-dibromo- 1,1,2,2,3,3,4,4,5,5-decaphenylpentasilane. The numbering of the phenyl groups is unnecessary, as the shorter name is unambiguous. Also, again to avoid long series of num­ bers for silane derivatives containing the Si-H group, the naming is accomplished by prefixing to the rest of the name a position symbol, followed by italic capital H, for each such group. Therefore, HSiPhg(SiPhg )j-SiPh 2H will be named lH,7H-tetradecaphenylheptasilane, and HSiPhg(SiPhg)gSiPhgOH will be 4H-octaphenyltetrasilan-l-ol. Organosilicon compounds containing chains of silicon atoms in a cycle will be named as derivatives of cyclic silicon compounds having the formula (SiHg)n and will be called cyclotrisilanes, cyclotetrasilanes, etc., according to the number of members in the ring; they will have the generic name cyclosilanes. Cyclosilanes