Ii B Group Metal Organic Complexes Of Nonlinear Optical Materials

Nonlinear optical (NLO) materials have always been an active part in the field of materials research during the last several decades. Now they have extensive applications in the high-speed developing information industry. They not only play an important part in solid state laser technique as frequency-conversion materials, but also have promising applications in the technology of information transmission, storage, extraction, processing and display, etc. People have always devoted themselves into searching of different kinds of novel NLO materials since years. Metal-organic coordination compounds were introduced into the field of NLO materials about twenty years ago. They have the merits of both inorganic and organic materials, so they have attracted many researchers. Among these metal-organic coordination materials there is a kind of compounds in which the center metal atoms are the Group 12 elements. Comparing with other metal-organic coordination compounds, this kind of compounds is usually colorless and has a smaller UV cutoff wavelength. Therefore, they are better NLO materials for blue-violet generation by direct frequency-doubling of laser diode.Since 1980s, many kinds of Group 12 metal-organic NLOmaterials have been prepared by our research group. The ligands include thiourea, thiosemicarbazide, allylthiourea, thiocyanate, and so on. Among them, metal-allylthiourea coordination compounds (ATM'X type) and bimetallic thiocyanates (ABTC type) are prominent. Both types of crystals have strong NLO efficiency, deep UV cutoff wavelength and stable physico-chemical properties as well as the crystal growth can be realized. Milliwatts violet 404nm radiation has been generated by frequency doubling of diode laser in ZnCd(SCN)4 (abbreviated as ZCTC) and CdHg(SCN)4 (abbreviated as CMTC) crystals.In this dissertation, some novel coordination compounds belonging to the ATM'X or ABTC type were prepared for nonlinear optics. The structures and some properties of the synthesized new compounds were characterized. Then the relations between the structure and properties of the same type of compounds was studied and discussed. The summaries of this thesis are as follows:1. Two novel coordination crystals Zn(AT)3Cl2 (abbreviated as ATZC) and Zn(AT)3Br2 (abbreviated as ATZB) were synthesized and grown for the first time. The crystal structure of ATZC was determined on 4-circle diffractometer. The results show that it belongs to spacegroup R3, having minor difference with the other four reported ATM'X compounds, which belong to R3c. But they all have a same molecular structure, including a metal centered M'S3X tetrahedron with microcosmic dipole moment. The dipole moments in each molecules have the same orientation, so the whole crystal shows a considerable high NLO efficiency.2. The spectroscopy, calorifics and NLO properties of the two crystals ATZC and ATZB were characterized for the first time. The results show that ATZC shows powder SHG efficiency comparative to urea, and ATZB higher than urea. They both have wide transparence band, and the UV cutoff wavelength is 290 and 320nm, respectively. So they are potential materials for generating blue-violet laser by direct frequency-doubling of laser diode.3. The structures and properties of the six crystals of ATM'X type were systematically studied. And the relations between the structure and properties are discussed. Some of the conclusions are: The thermal stability and NLO efficiency increase with the increasing metal atom number; the UV cutoff wavelength is affected by the electronegativity of the matel and halogen atoms, and the metal atom is the predominate factor.4. Three new ABSC type of NLO materials: ZnCd(SeCN)4 (abbreviated as ZCSC), CdHg(SeCN)4 (abbreviated as CMSC) and ZnHg(SeCN)4 (abbreviated as ZMSC) were prepared for the first time. The crystal structures of the former two compounds were determined. It shows that ABSC the same structure with ABTC crystal, so the two types of crystals are isostructural. As in ABTC, the -SeCN- in ABSC bridge the tetrahedrally coordinated N-bonded A atoms and the tetrahedrally coordinated S-bonded B atoms into a diamondiod 3-D network. Their high hyperpolarizability come from the extended p-n conjugation of the A-NCSe-B bridges and their parallel alignments in the 3-D crystal structure.5. The spectroscopy, calorifics and NLO properties of the three novel materials: ZCSC, CMSC and ZMSC were characterized The results show that the three materials show powder SHG efficiency higher than urea; and the thermal stability of them is better than the materials of ABTC type.In conclusion, this dissertation reports the preparation and characterization of five new coordination compound NLO materials, two with ATM'X type, three with ABSC type. The finding of the five compounds makes the two system types integrated. These studies areimportant not only for searching after novel coordination compound NLO materials but also for the coordination chemistry of Group 12metal.