CRYSTAL STRUCTURES OF SOME ACRIDINE DIONES - LASER ACTIVE COMPOUNDS. K. Gunasekaran, V.K. Ganesh, D. Velmurugan. Department of Crystallography and Biophysics, University of Madras, Madras 600 025, India; S. Ramasubbu, Department of Oral Biology, SUNY, Buffalo, USA; K. Panneerselvam and Manuel Soriano-Garcia, Instituto de quimica UNAM, circuito Exterior, cd. Univ, Mexico D.F. 04510, Mexico; V.T. Ramakrishnan, Department of Organic Chemistry, University of Madras, Madras -25

DNA intercalating property is considered as one of the potent factor for DNA binding drugs. Acridine orange and 9-amino acridine are widely studied towards underdstanding their intercalating behaviour. Here three acridine diones which are showing laser activity are taken for crystallographic study as the first phase of work for their binding nature studies with DNA. (1)9-vinyl-10-methyl, (2)9-phenyl, 3,4,6,9,10 hexahydro 2,2,8,8 tetramethyl 1,8 acridine dione and (3) 9-(4-methoxyphenyl)-10- phenyl 3,4,6,9,10 hexahydro 1,8 acridine dione. Preliminary results:

      a         b         c         (     (       (       
1     14.578(1  15.398(2  8.646(1)  90    90      90      
      )         )                                         
2     17.618(2  17.618(2  10.121(2  90    90      90      
      )         )         )                               
3     8.670(1)  11.140(1  21.198(1  90    92.5(1  90      
                )         )               )               

The space groups are Pnma, P42/n and P21/n respectively. The final R factor for the three are 0.061, 0.049 and 0.051 respectively. In all the three cases the compound itself folded into different extents and the substituents are in cis type orientations. The conformational details will be presented.