Coupling of benzyl halides mediated through alkali metal supramolecular complexes. A novel route to poly(p‐xylylene)

Abstract

Coupling of benzyl bromide giving I ,Zdiphenylethane was demonstrated to proceed at room temperature in THF solution mediated by the potassium/l8-crown-6 supramolecular complex. Based on this model reaction a novel method for the low temperature synthesis of poly@-xylylene) from a,a'-dibromo-p-xylene is proposed. Experimental evidence of the polymer structure was provided by solid-state l C NMR and IR spectroscopy.

Electron-transfer reduction of selected alcohols with alkalide K−, K+(15-crown-5)2 via organometallic intermediates

“…¼ 50-51°C/16 mm Hg. Mass spectrum (m=e): 134 [M þ , 4]; 116 (7); 105 (11); 91 (100); 77 (7); 65 (30); 51 (9); 39 (11). 1 H and 13 C NMR spectra (in CDCl 3 ) have been already presented in [39,40].…”

“…They are known as two-electron-transfer species [5], used in the reactions with alkenes [6][7][8][9], alkines [10], alkyl halides [11,12], silyl halides [13], ketones [14,15], esters [16][17][18][19][20], and ethers [12,[20][21][22][23][24][25][26][27][28]. Organometallic compounds were intermediate products in those systems.…”

Electron-Transfer Processes Mediated by Alkalides: A Critical Approach

“…The coupling of benzyl bromide 28 proceeded smoothly with K − , K + (18C6) (Scheme 10) [97]. Bibenzyl 29 was the main reaction product.…”

“…Poly-coupling occurred if difunctional α,α'-dibromo-p-xylene was used in the reaction with K − , K + (18C6) yielding poly(p-xylene) [97]. It was also reported that polysilanes and cyclic silane oligomers were produced in the polymerization of methylphenyldichlorosilane with K − , K + (18C6) [98].…”

Stepwise Two-Electron-Transfer Reduction of Cyclic Ethers and Lactones with Alkalide K-, K+(15-Crown-5)2

“…K , K + (15-crown-5) 2 , K , K + (18-crown-6) and Na , K + (18-crown-6), are known as powerful reducing agents of alkenes [1][2][3][4], alkynes [5], halides [6][7][8], ketones [9,10], esters [11][12][13][14][15] and ethers [15][16][17][18][19][20]. The reaction proceeds with the transfer of two valence electrons from the metal anion to acceptor molecules.…”