Electrochemical Deposition of N-Heterocyclic Carbenes

Abstract

A carbene coated metal surface is formed by applying a positive potential on a metal surface. applying a negative potential to a counter electrode and contacting them with a solution comprising free carbene, a salt of carbene, or a combination.

1 . A method of forming a coating on a metal surface of a substrate, comprising:
 applying a positive potential to a first metal surface on a substrate to form a working electrode;   applying a negative potential to a second metal surface or a conductive surface of a substrate to form a counter electrode;   disposing the working electrode and counter electrode in a solution comprising free carbene, a salt of carbene, or a combination; and   producing a coated metal surface,   wherein the positive potential and negative potential are referenced to a reference electrode of substantially equivalent potential to a Ag/AgCl electrode.   
     
     
         2 . The method of  claim 1 , wherein the conductive surface comprises carbon, graphite, silicon, germanium, gallium arsenide, or a combination thereof. 
     
     
         3 . The method of  claim 1 , wherein the second metal surface comprises a metal that is the same as the metal of the working electrode. 
     
     
         4 . The method of  claim 3 , wherein the first metal surface comprises gold. 
     
     
         5 . The method of  claim 1 , wherein the first metal surface is substantially unprotected. 
     
     
         6 . The method of  claim 5 , wherein substantially unprotected is substantially unoxidized. 
     
     
         7 . The method of  claim 1 , wherein the salt of carbene is a N-heterocyclic carbene benzimidazolium hydrogen carbonate salt. 
     
     
         8 . The method of  claim 7 , wherein the N-heterocyclic carbene benzimidazolium hydrogen carbonate salt is 5-(dodecyloxy)-1,3-diisopropyl-1H-benzo[d]imidazole-3-ium hydrogen carbonate (NHC-2·HCO 3 ). 
     
     
         9 . The method of  claims 1 , wherein the positive potential is in a range of 0.1 to 2.0 V. 
     
     
         10 . The method of  claim 1 , wherein the working electrode comprises gold, copper, iron, or a combination. 
     
     
         11 . The method of  claim 9 , wherein the positive potential is in a range of 0.8 to 1.0 V. 
     
     
         12 . The method of  claim 1 , wherein the coating is an electron passivation layer. 
     
     
         13 . The method of  claim 1 , wherein the coating prevents or reduces corrosion. 
     
     
         14 . The method of  claim 1 , wherein once coated, the first metal surface has reduced reactivity relative to its uncoated form. 
     
     
         15 . The method of  claim 1 , wherein the disposing in the solution occurs for about 1 min to about 5 h. 
     
     
         16 . The method of  claim 15 , wherein the disposing occurs for about 1 min to about 120 min. 
     
     
         17 . The method of  claim 1 , further comprising a reference electrode, a salt bridge, or both. 
     
     
         18 . The method of  claim 1 , wherein the metal is selected from the group consisting of scandium; titanium; vanadium; chromium; manganese; iron; cobalt; nickel; copper; zinc; yttrium; zirconium; niobium; molybdenum; technetium; ruthenium; rhodium; palladium; silver; cadmium; lanthanum; hafnium; tantalum; tungsten; rhenium; osmium; iridium; platinum; gold; mercury; actinium; rutherfordium; dubnium; seaborgium; bohrium; hassium; meitnerium; darmstadtium; roentgenium; copernicium; beryllium; magnesium, calcium, strontium; barium; radium; lithium; sodium; potassium; rubidium; cesium; francium; scandium; lanthanum; cerium; praseodymium; neodymium; samarium; yttrium; dysprosium; holmium; erbium; thulium; ytterbium; lutetium; and combinations of metals such as an alloy, brass, steel, bronze, aluminum alloys, tin, and monel. 
     
     
         19 . The method of  claim 1 , wherein the free carbene is a N-heterocyclic carbene benzimidazole. 
     
     
         20 . The method of  claim 19 , wherein the N-heterocyclic carbene benzimidazole is 1,3-diisopropyl-5-(dodecyloxy)-1H-benzo[d]imidazole-2-ylidene (NHC-2).