Electrochemical Deposition of Selenium in Ionic Liquids

Abstract

The invention relates to a process for the electrochemical deposition of grey selenium on a substrate in an ionic liquid, where the electrochemical deposition can be carried out at temperatures of greater than 10000.

1 . Process for the electrochemical deposition of grey selenium on a substrate in at least one ionic liquid. 
     
     
         2 . Process according to  claim 1 , characterized in that the ionic liquid has at least one tetraalkylammonium or tetraalkylphosphonium cation, where the alkyl groups may each, independently of one another, have 1 to 10 C atoms, or a heterocyclic cation selected from 
       
         
           
           
               
               
           
         
         where 
         R 1 ′ to R 4 ′ each, independently of one another, denote hydrogen, —CN, —OR′, —NR′ 2 , —P(O)R′ 2 , —P(O)(NR′ 2 ) 2 , —C(O)R′, 
         straight-chain or branched alkyl having 1-20 C atoms, 
         straight-chain or branched alkenyl having 2-20 C atoms and one or more double bonds, 
         straight-chain or branched alkynyl having 2-20 C atoms and one or more triple bonds, saturated, partially or fully unsaturated cycloalkyl having 3-7 C atoms, which may be substituted by alkyl groups having 1-6 C atoms, 
         saturated, partially or fully unsaturated heteroaryl, 
         heteroaryl-C 1 -C 6 -alkyl or aryl-C 1 -C 6 -alkyl, 
         where the substituents R 1 ′, R 2 ′, R 3 ′ and/or R 4 ′ together may also form a ring system, 
         where one or more substituents R 1 ′ to R 4 ′ may be partially or fully substituted by halogens, in particular —F and/or —Cl, or —OR′, —CN, —C(O)OH, —C(O)NR′ 2 , —SO 2 NR′ 2 , —C(O)X, —SO 2 OH, —SO 2 X, —NO 2 , but where R 1 ′ and R 4 ′ cannot simultaneously be fully substituted by halogens, and where one or two non-adjacent and non-heteroatom-bonded carbon atoms of the substituents R 1 ′ to R 4 ′ may be replaced by atoms and/or atomic groups selected from —O—, —S—, —S(O)—, —SO 2 —, —C(O)—, —N + R′ 2 —, —C(O)NR′—, —SO 2 NR′—, —P(O)(NR′ 2 )NR′—, —PR′ 2 ═N— or —P(O)R′—, where R′═H, non-, partially or perfluorinated C 1 — to C 6 -alkyl, C 3 — to C 7 -cycloalkyl, unsubstituted or substituted phenyl, and X=halogen. 
       
     
     
         3 . Process according to  claim 1 , characterized in that the ionic liquid contains at least one tetraalkylammonium, tetraalkylphosphonium-, 1,1-dialkylpyrrolidinium, 1-hydroxyalkyl-1-alkylpyrrolidinium, 1-hydroxyalkyl-3-alkylimidazolium or 1,3-bis(hydroxyalkyl)imidazolium cation, where the alkyl groups or the alkylene chain of the hydroxyalkyl group may each, independently of one another, have 1 to 10 C atoms. 
     
     
         4 . Process according to  claim 1 , characterized in that the ionic liquid has an electrochemical window from 0 mV to −3500 mV against ferrocene/ferrocinium in the cathodic branch and from 0 mV to +3500 mV against ferrocene/ferrocinium in the anodic branch. 
     
     
         5 . Process according to  claim 1 , characterized in that the anion of the ionic liquid is selected from the group PF 6 , BF 4 , alkylsulfate, perfluoroalkylsulfonate, perfluoroacetate, bis(fluorosulfonyl)imide, bis(perfluoroalkylsulfonyl)imide, tris(perfluoroalkyl)trifluorophosphate, bis(perfluoroalkyl)tetrafluorophosphate, tris(perfluoroalkylsulfonyl)methide or perfluoroalkylborate. 
     
     
         6 . Process according to  claim 1 , characterized in that the cation is selected from the group linear or branched tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium, tetrapentylammonium, tetrahexylammonium, tetraheptylammonium, tetraoctylammonium, tetranonylammonium, tetradecylammonium, trimethylalkylammonium, trimethyl(ethyl)ammonium, triethyl(methyl)ammonium, trihexylammonium, methyl(trioctyl)ammonium, tetramethylphosphonium, tetraethylphosphonium, tetrapropylphosphonium, tetrabutylphosphonium, tetrapentylphosphonium, tetrahexylphosphonium, tetraheptylphosphonium, tetraoctylphosphonium, tetranonylphosphonium, tetradecylphosphonium, trihexyltetradecylphosphonium, triisobutyl(methyl)phosphonium, tributyl(ethyl)phosphonium, tributyl(methyl)phosphonium, 1,1-dimethylpyrrolidinium, 1-methyl-1-ethylpyrrolidinium, 1-methyl-1-propylpyrrolidinium, 1-methyl-1-butylpyrrolidinium, 1-methyl-1-pentylpyrrolidinium, 1-methyl-1-hexylpyrrolidinium, 1-methyl-1-heptylpyrrolidinium, 1-methyl-1-octylpyrrolidinium, 1-methyl-1-nonylpyrrolidinium, 1-methyl-1-decylpyrrolidinium, 1,1-diethylpyrrolidinium, 1-ethyl-1-propylpyrrolidinium, 1-ethyl-1-butylpyrrolidinium, 1-ethyl-1-pentylpyrrolidinium, 1-ethyl-1-hexylpyrrolidinium, 1-ethyl-1-heptylpyrrolidinium, 1-ethyl-1-octylpyrrolidinium, 1-ethyl-1-nonylpyrrolidinium, 1-ethyl-1-decylpyrrolidinium, 1,1-dipropylpyrrolidinium, 1-propyl-1-butylpyrrolidinium, 1-propyl-1-pentylpyrrolidinium, 1-propyl-1-hexylpyrrolidinium, 1-propyl-1-heptylpyrrolidinium, 1-propyl-1-octylpyrrolidinium, 1-propyl-1-nonylpyrrolidinium, 1-propyl-1-decylpyrrolidinium, 1,1-dibutylpyrrolidinium, 1-butyl-1-pentylpyrrolidinium, 1-butyl-1-hexylpyrrolidinium, 1-butyl-1-heptylpyrrolidinium, 1-butyl-1-octylpyrrolidinium, 1-butyl-1-nonylpyrrolidinium, 1-butyl-1-decylpyrrolidinium, 1,1-dipentylpyrrolidinium, 1-pentyl-1-hexylpyrrolidinium, 1-pentyl-1-heptylpyrrolidinium, 1-pentyl-1-octylpyrrolidinium, 1-pentyl-1-nonylpyrrolidinium, 1-pentyl-1-decylpyrrolidinium, 1,1-dihexylpyrrolidinium, 1-hexyl-1-heptylpyrrolidinium, 1-hexyl-1-octylpyrrolidinium, 1-hexyl-1-nonylpyrrolidinium, 1-hexyl-1-decylpyrrolidinium, 1,1-dihexylpyrrolidinium, 1-hexyl-1-heptylpyrrolidinium, 1-hexyl-1-octylpyrrolidinium, 1-hexyl-1-nonylpyrrolidinium, 1-hexyl-1-decylpyrrolidinium, 1,1-diheptylpyrrolidinium, 1-heptyl-1-octylpyrrolidinium, 1-heptyl-1-nonylpyrrolidinium, 1-heptyl-1-decylpyrrolidinium, 1,1-dioctylpyrrolidinium, 1-octyl-1-nonylpyrrolidinium, 1-octyl-1-decylpyrrolidinium, 1-1-dinonylpyrrolidinium, 1-nonyl-1-decylpyrrolidinium or 1,1-didecylpyrrolidinium, 1-hydroxymethyl-1-methylpyrrolidinium, 1-hydroxymethyl-1-ethylpyrrolidinium, 1-hydroxymethyl-1-propylpyrrolidinium, 1-hydroxymethyl-1-butylpyrrolidinium, 1-(2-hydroxyethyl)-1-methylpyrrolidinium, 1-(2-hydroxyethyl)-1-ethylpyrrolidinium, 1-(2-hydroxyethyl)-1-propylpyrrolidinium, 1-(2-hydroxyethyl)-1-butylpyrrolidinium, 1-(3-hydroxypropyl)-1-methylpyrrolidinium, 1-(3-hydroxypropyl)-1-ethylpyrrolidinium, 1-(3-hydroxypropyl)-1-propylpyrrolidinium, 1-(3-hydroxypropyl)-1-butylpyrrolidinium, 1-(4-hydroxybutyl)-1-methylpyrrolidinium, 1-(4-hydroxybutyl)-1-ethylpyrrolidinium, 1-(4-hydroxybutyl)-1-propylpyrrolidinium or 1-(4-hydroxybutyl)-1-butylpyrrolidinium, 1-(1-hydroxymethyl)-3-methylimidazolium, 1-(1-hydroxymethyl)-3-ethylimidazolium, 1-(1-hydroxymethyl)-3-propylimidazolium, 1-(1-hydroxymethyl)-3-butylimidazolium, 1-(2-hydroxyethyl)-3-methylimidazolium, 1-(2-hydroxyethyl)-3-ethylimidazolium, 1-(2-hydroxyethyl)-3-propylimidazolium, 1-(2-hydroxyethyl)-3-butylimidazolium, 1-(3-hydroxypropyl)-3-methylimidazolium, 1-(3-hydroxypropyl)-3-ethylimidazolium, 1-(3-hydroxypropyl)-3-propylimidazolium, 1-(3-hydroxypropyl)-3-butylimidazolium, 1-(4-hydroxybutyl)-3-methylimidazolium, 1-(4-hydroxybutyl)-3-ethylimidazolium, 1-(4-hydroxybutyl)-3-propylimidazolium, 1-(4-hydroxybutyl)-3-butylimidazolium, 1,3-bis(1-hydroxymethyl)imidazolium, 1,3-bis(2-hydroxyethyl)imidazolium, 1,3-bis(3-hydroxypropyl)imidazolium, 1,3-bis(4-hydroxybutyl)imidazolium, 1-(2-hydroxyethyl)-3-(1-hydroxymethyl)imidazolium, 1-(2-hydroxyethyl)-3-(3-hydroxypropyl)imidazolium, 1-(2-hydroxyethyl)-3-(4-hydroxybutyl)imidazolium, 1-(3-hydroxypropyl)-3-(1-hydroxymethyl)imidazolium, 1-(3-hydroxypropyl)-3-(2-hydroxyethyl)imidazolium, 1-(3-hydroxypropyl)-3-(4-hydroxybutyl)imidazolium, 1-(4-hydroxybutyl)-3-(1-hydroxymethyl)imidazolium, 1-(4-hydroxybutyl)-3-(2-hydroxyethyl)imidazolium or 1-(4-hydroxybutyl)-3-(3-hydroxypropyl)imidazolium. 
     
     
         7 . Process according to  claim 1 , characterized in that selenium ions are in dissolved form in the ionic liquid. 
     
     
         8 . Process according to  claim 7 , characterized in that the selenium ions are produced by dissolution of a selenium salt. 
     
     
         9 . Process according to  claim 1 , characterized in that the substrate is a non-metal, semi-metal, metal, metal alloy or conductive and/or metallized ceramics or conductive and/or metallized plastic. 
     
     
         10 . Process according to  claim 1 , characterized in that the process is carried out at temperatures between 10° C. and 230° C. 
     
     
         11 . Substrates coated by a process according to  claim 1 . 
     
     
         12 . Use of ionic liquids for the deposition of grey selenium on a substrate.