The crystal and molecular structure of the polymethine dye 1,3-bis(dimethylamino)trimethinium perchlorate: a comparison of optical and X-ray crystal structure determination

Abstract

The crystal and molecular structure of the polymethine dye 1,3-bis(dimethylamino)trimethinium perchlorate has been determined by X-ray diffraction techniques and refined to a residual of 6-9 %. The space group is Cc and the unit-cell parameters are a = 7.86 + 0.04, b = 18"93 + 0.12, e = 7.70_+ 0.05 A, fl=103"55+0.18 °. From the refined coordinates, the transition moments of the two non-parallel molecules in the unit cell were found to have direction cosines of 0.431, 0.879, 0.205 and 0.431, -0.879, 0.205 relative to orthogonal axes parallel to a*, b and e. The orientation of the dye molecules in the crystal is compared with predictions made by P. Gramaccioni and W. T. Simpson (unpublished results) on the basis of spectroscopic measurements, and the agreement between the X-ray and the optical studies is found to be excellent.

The crystal and molecular structure of the "metallic reflector" 1,5-bis(dimethylamino)pentamethinium perchlorate

“…125( 2) 117(4) 0(2)-Cl-0 (7) 109(4) 0(2)-Cl-0 (8) 89( 4) 0(4)-Cl-0 (7) 109( 4) 0(4)-Cl-0 (8) 130( 5) 0(7)-Cl-0(8) 100(4) atoms is shorter than the value expected12 for aromatic compounds (1.395 Á).…”

“…The crystal packing is illustrated in Figure 4. Orientation of the adjacent dye molecules is such that there are numerous mutual intermolecular approaches ranging upward from a minimum value of 3.50 Á for C(2)-C (8). Interaction of the perchlorates with the polymethinium chains is expected to be of ionic character and the closest approaches of this kind occur between 0(4) and C(9) (2.95 Á) and 0(2) and N(2) (3.20 Á).…”

“…[4][5][6] The structure of anthracene is well known7 and we have previously described the structure of the three-carbon dye l,3-bis(dimethylamino)trimethinium perchlorate (BDTP). 8 In this report we describe the crystal structure of the five-carbon analogue BDP, which provides the most striking example of metallike reflection described to date.…”

cis-1-Acetyl-4-[1-(4-bromophenyl)-2-phenyl]-vinyl-3-pyrrolin-2-one

“…Three-dimensional data were collected to sin 0/2=0.66 A -1 on a card-controlled Enraf-Nonius three-circle diffractometer with nickel-filtered Mo K~ radiation (2=0.7107 A) (cf, Matthews, Stenkamp & Colman, 1973). Of 3729 reflections measured, 1429 were considered to have significant intensity [I> 2a(I)].…”