|Budget Amount *help
¥2,700,000 (Direct Cost : ¥2,700,000)
Fiscal Year 1998 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1997 : ¥1,900,000 (Direct Cost : ¥1,900,000)
1. Two-Dimensional Stacking of (Dipyridophenazine)platinum(II) Complexes. Novel platinum(II) complexes containing dipyrido[3,2-a : 2', 3'-c]phenazine (dppz) have been found to form two-dimensional stackingstructures which have constructed with both platinum-platinum and ligand pi-pi interactions in the crystals.
2. Crystal Structures and Emission Properties of Diimine-platinum(II) Complexes Controlled by Various Intermolecular Interactions. Temperature dependence of emission spectra and crystal structures has been investigated for the linear-chain platinum(II) complexes, red forms of [Pt(CN)_2(bpy)] (bpy = 2,2'-bipyridine) and [Pt(CN)_2(i-biq)] (i-biq = 3,3'-biisoquinoline). For [Pt(CN)_2(bpy], a good correlation between the _3MLCT emission energy and the Pt-Pt distance has been obtained in the temperature range of 300-15 K.For [Pt(CN)_2(i-biq)], however, the shrinkage occurs between the stacks instead of the Pt-Pt spacing with decreasing temperature, which is due to an increase in the
inclination angle of the complex units in the stack. With decreasing temperature, the _3pipi*(i-biq) emission appears, in addition to the _3MLCT emission. These results indicate that the pi-pi and Pt-Pt interactions competitively play important roles in controlling the crystal structure and the emission state, For these complexes, concentration-dependent assemblage was found in a dilute glassy solution at 77 K : In addition to a structured _3pipi* emission band at lambda_<max> = 530 nm, a broad band appeared at a range of 600-800 nm and the relative intensity was increased with concentration. The emission behavior suggests the formation of dimeric (or oligomeric) species with Pt-Pt interaction in extremely dilute solution.
3. Selective Uptake of Free Phenanthroline by (Diimine)(ethylenediamine)platinum(II). When non-planar ethylenediamine (en) is used as another ligand, the steric hindrance prevents the complexes from stacking with Pt-Pt interactions. We have found that this type of complexes, [Pt(en)(L)]^2+(L = bpy, phen [1,10-phenanthroline]), form a 1 : 1 integrated stack with free phenanthrolines. The pi-pi interactions and the hydrogen bonds stabilize the stack. Interestingly, the inclusion of phen in the integrated stack is selective among many aromatic compounds, which is very informative on the molecular recognition. Less