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Synthesis of Tetrathiafulvalene Derivatives via Polymer Bound Triphenylphosphine

IP.com Disclosure Number: IPCOM000087809D
Original Publication Date: 1977-Mar-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Engler, EM: AUTHOR

Abstract

The most general method for preparing tetrathiafulvalene derivatives (1) involves the use of phosphorus bases to affect coupling of the dithiole precursors (2) [1]. Further, this reaction is the only means capable of preparing selenium derivatives of 1 (X = Se). When R = H and Y = S, the use of phosphorus bases does not work; only when Y = Se does the coupling reaction succeed [2].

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Synthesis of Tetrathiafulvalene Derivatives via Polymer Bound Triphenylphosphine

The most general method for preparing tetrathiafulvalene derivatives (1) involves the use of phosphorus bases to affect coupling of the dithiole precursors
(2) [1]. Further, this reaction is the only means capable of preparing selenium derivatives of 1 (X = Se). When R = H and Y = S, the use of phosphorus bases does not work; only when Y = Se does the coupling reaction succeed [2].

A problem with the use of phosphorus bases is that unreacted phosphorus base and a by-product from the reaction, a phosphoroselenoate (3), are difficult to separate from R'P--- Se, where R' is an alkyl or phenyl group 3. the tetrathiafulvalene (1) product. Typically, a column chromatographic separation has to be carried out. The separation is complicated due to the similar chromatography retention times of tetrathiafulvalene derivatives and the phosphorus bases. The presence of the phosphorus base prevents crystallization of the product, leading to oiling of the product and has to be carefully removed by chromatography. Also, the yield of the tetrathiafulvalene product is lowered due to the air sensitivity of many tetrathiafulvalene derivatives which are oxidized to their radical cation salts during the chromatography.

An improvement in the coupling reaction is described in which the phosphorus base is attached to preformed insoluble polymer support. Unreacted phosphorus base and phosphoroselenoate by-product are simply removed by filtering, thus eliminating the isolation and purification p...