Synthesis And Nonlinear Optical Studies Of Gold N-heterocyclic Carbenes Complexes

Nonlinear Optical(NLO) materials which have the advantage in storing and processing information with large capacity have attracted more and more attention from scholars.Designing materials with better NLO properties has become one hot spot of NLO field.However, organometallics have played an increasingly important role in NLO field due to the advantages of both organic and inorganic materials.Nowadays introducing new and better organic ligands into Nonlinear Optical(NLO)fields has become effective method of designing organometallics complexes with excellent NLO properties. Not only the structure theoretical analysis of N-heterocyclic carbene(NHC)but also the NHC application in many fileds such as catalysis, light emitting materials and medical chemistry have proven that it is ourstanding organic ligand. But there is no report about the NHC application in the NLO filed although NHC is the most successful analogue of phosphorus ligand. Based on this situation, this paper try to introduce the NHC into NLO filed firstly and explore its potential in this filed.Firstly, We repeatedly used Sonogashira coupling reaction and desilylation reaction to prepare four arylethynylenes with different chain length, and then two series of compounds were synthesized by reaction of four arylethynylenes abolve with gold-NHC and aniline respectively. One series of compounds is gold-NHC complexes with phenylacetylenes as conjugated bridge, namely 1,3,5-{[(NHCiPr)-Au]C≡C}3C6H3(5), 1,3,5-{[(NHCiPr)Au]C≡-C-4-C6H4-1-C≡C}3C6H3(6), 1,3,5-{4-([(NHCiPr-)Au]C≡C-4-C6H4-1-C≡C)-3,5-Et2C6H2-1-C-≡C}3C6H3(7), 1,3,5-{4-([(NHCiPr)Au]C≡C-4-C6-H4-1-C≡C-4-C6H4-1-C≡C)-3,5-Et2C6H2-1-C≡C}3C6H3(8) respectively, The other series is aniline compounds with same conjugated bridge and uesed to contrast with gold-NHC complexes, namely1,3,5-(4-Ph2NC6H4-1-C≡C)3C6H3(9), 1,3,5-(4-Ph2NC6H4-1-C≡C-4-C6H4-1-C≡C)3C6H3(10),1,3,5-{4-(4-Ph2NC6H4-1-C≡C-4-C6H4-1-C≡C)-3,5-Et2C6H2-1-C≡C}3C6H3(11), 1,3,5-{4-(4-Ph2NC6H4-1-C≡C-4-C6H4-1-C≡C-4-C6H4-1-C≡C)-3,5-Et2C6H2-1-C≡C}3C6H3(12)respectively. Secondly, All compounds were characterized by IR, 1H and 13C-NMR, mass spectrometry and elemental analysis where possible, And the characterization results have confirmed that we got correct products.Finally, Products have been run the optical tests, namely linear optical studies through UV-vis measurements and NLO studies through Z-scan technique. The UV-vis test result indicated that nonlinear polarizability can be increased by increasing the conjugate system,and this kind of positive effect will be decreased with the increase of conjugate system. The Z-scan result indicated that some degree of optical limiting ability although it’s not outstanding, and had proven that NHCs have certain potential for NLO.