| 摘要 |
PCT No. PCT/JP92/00295 Sec. 371 Date Nov. 12, 1992 Sec. 102(e) Date Nov. 12, 1992 PCT Filed Mar. 12, 1992 PCT Pub. No. WO92/16538 PCT Pub. Date Oct. 1, 1992.The object of the invention is to provide a novel compound exhibiting stable photochromism. The invention is directed to a transition metal-spirobenzothiopyran complex of the general formula (* CHEMICAL STRUCTURE *) wherein R1 for example be C1-20 alkyl; R2, R3, R4, R5, R6, R7 and R8 independently may mean hydrogen; Y means O or S; M may for example be Cr, and a process for producing the complex.
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