| Recently, molecular materials with nonlinear optical (NLO) properties are attracting considerable attention because of their potential applications in optoelectronic devices of telecommunications, information storage, and signal processing.Carborane is an important specie of borane derivatives and have applied in many fields due to its representative structure and special bond. Recently, with the development of nonlinear optical study and the prospect of NLO material application, the theoretical computations on carborane derivatives as NLO material have received more attention. To prove the rigidity structure and great thermodynamic stability, Allis et al designed a series of molecules linking icosahedral carborane polyhedra as bridge, employed semiempirical methods to optimize the structures and calculate their first hyperpolarizability. Metal organic complexes with potential nonlinear optical property, good thermal and photochemical stability and redox switching ability have been of considerable interest. Scientific research institutes have put more efforts into the study of ferrocene complexes, and have achieved important conclusions, since Green reported that ferrocene complexes have excellent second harmonic generation (SHG) in 1987. Matllacarboranes originated some 40 years ago in the laboratory of Hawthorne,when polyhedral borane chemistry area and transition metal organometallics area could hardly have seemed more dissimilar. The two areas were effectively joined by the preparation and structural characterization of the first metal-carborane sandwich complexes. Metallacarboranes are applied in various fields due to unique structure and property. Metallacarboranes containing carborane ligands possessing a pentagonal open face are quite similar to metallocenyl complexes.In this paper, we calculate and analyze NLO properties on series of complexes containing carborane and metallacarborane. The results of our studies in this thesis are:1. DFT B3LYP/LANL2DZ method was employed to calculate electron properties and the second-order nonlinear optical respond of platinum (II) complexes. 4,7-diphenyl-1,10- phenanthroline shows the ability to push electron in these complexes. Metal Pt plays a balancing charge role. The polarizability and second-order nonlinear coefficient of seven complexes are calculated by FF method. Introduction of carborane chromophore leads to remarkable polarizability increase. Theβvecof the complex containing di-thiocarborane chromophore is bigger than that of the complex containing bis-thiocarborane chromophore.2. Density functional theory (DFT) B3LYP method was employed to calculate electron properties and the second-order nonlinear optical responses of the derivatives which were formed by (C5H5)Co(C2B4H6) and–CH=CH–C6H4–NO2,–CH=CH–C6H4–NH2. The results show: (C5H5)Co(C2B4H6) shows the ability of pushing electrons, when it connected with pulling electron groups. While, (C5H5)Co(C2B4H6) also shows the ability of pulling electrons, when it connected with pushing electron groups. Then, (C5H5)Co(C2B4H6) can be either a donator or an acceptor. Both the transition between frontier molecular orbitals and the transitions between deeper layer orbitals obviously contributed to second-order NLO coefficients.3. Quantum chemistry DFT B3LYP/6-31G* method was employed to calculate the second-order nonlinear optical properties of the derivatives of disubstituted 7-vertex cobaltacarborane metallocenyl. The calculation results show that the dipole moments, polarizabilities and first hyperpolarizabilities of the derivatives of disubstituted 7-vertex cobaltacarborane metallocenyl are all related to molecular configuration and the properties of substitutents. In the derivatives of disubstituted 7-vertex cobaltacarborane metallocenyl, the molecular configuration with two H atoms at meta position in cyclopentadiene substituted by substitutents is more beneficial to charge transfer. Accordingly, the molecules have large hyperpolarizabilities. |
