CONTROL OF OPTICAL-PROPERTIES OF CU(II) COMPLEXES FORMED WITH PHOSPHATE LIGANDS IN TRANSPARENT RESIN AND APPLICATIONS TO NEAR-INFRARED RAY CUTOFF FILTER CONTAINING THE COMPLEX

The relationships among mole ratio, light absorption peak, and coordin ation state of the Cu(II) complex formed with methacryloyloxyethyl pho sphate (PMOE) in poly (methyl methacrylate) were investigated by means of the mole ratio method. The resin containing the complex is suitabl e for use in a near infrared ray (NIR) cut off filter of which the opt ical properties can be adjusted. The wavelength of the light absorptio n peak of the Cu(II) complex in the polymer increased from 800 nm to 8 40 nm with increase in POH group concentration in the range 2 < mole r atio [OH group of phosphate group (OH)]/[Cu2+] < 6, and showed a const ant value 840 nm at 6 and above. Although COO group of methacryloyl gr oup coordinated at [OH]/[CU2+] = 2, POH groups successively replaced C OO groups strongly depending on POH group concentration in the range 2 < [OH]/[Cu2+] < 6. Then the complex was stabilized with 6 coordinatio n by POH groups in the range [OH]/[Cu2+] greater than or equal to 6. C ontrolling the absorption peak wavelength makes it possible to adjust the boundary wavelength between transmitting visible area and cutting off NIR area.