THE PHENOMENON OF CONGLOMERATE CRYSTALLIZATION .40. THE CRYSTALLIZATION BEHAVIOR OF TRANS-CO(III) AMINES (+)(546)-TRANS-[CO(3,2,3-TET)(NO2)(2)]CL-CENTER-DOT-3H(2)O (I), (-)(589)-TRANS-[CO(3,2,3-TET)CL-2]NO3 (II), AND OF (+)(546)-TRANS-[CO(3,2,3-TET)(NO2)(2)]NO3 (III)

A racemic solution of (I) crystallizes as a conglomerate from which a crystal we selected was found to be (+)(546)-trans-[Co(3,2,3-tet)(NO2)(2)]Cl . 3H(2)O (I), COClO7N6C8H28. It crystallizes in the enantiomorphic space group P2(1)2(1)2(1), with lattice constants a = 18.501(15) Angstrom, b = 14.433(2) Angstrom, and c = 6.441(3) Angstrom; V = 1720.07 Angstrom(3) and d(calc. M.W. = 414.73, Z = 4) = 1.601 g cm(-3). A total of 2305 data were collected over the range of 4 degrees less than or equal to 2 theta less than or equal to 55 degrees; of these, 1724 (independent and with I greater than or equal to 3 sigma(I)) were used in the structural analysis. Data were corrected for absorption (mu = 11.920 cm(-1)), and the relative transmission coefficients ranged from 0.8258 to 0.9565. Refinement was carried out for both lattice enantiomorphs, and at this stage the R(F) and R(W)(F) residuals were, respectively, 0.0381 and 0.0479 for (+++) and 0.0448 and 0.0532 for (---). Thus, the former was selected as correct for our specimen, and the final cycle of refinement with the (+++) model converged to R(F) and R(W)(F) of 0.0315 and 0.0365. A racemic solution of (II) crystallizes as a conglomerate from which a crystal we selected was found to be (-)(589)-trans-[Co(3,2,3-tet)Cl-2]NO3 (II), COCl2O3N5C8H22. It crystallizes in the enantiomorphic space group, P2(1) with lattice constants a = 6.395(2) Angstrom, b = 8.886(2) Angstrom, c = 13.185(2) Angstrom, and beta = 99.24(2)degrees; V = 739.59 Angstrom(3) and d(calc. M.W. = 366.14, Z = 2) = 1.646 g cm(-3). A total of 2912 data were collected over the range of 4 degrees less than or equal to 2 theta less than or equal to 64 degrees; of these, 2147 (independent and with I greater than or equal to 3 sigma(I)) were used in the structural analysis. Data were corrected for absorption (mu = 15.424 cm(-1)), and the relative transmission coefficients ranged from 0.9632 to 0.9985. Refinement was carried out for both lattice enantiomorphs, and the final R(F) and R(W)(F) residuals were, respectively, 0.0326 and 0.0328 for (+++) and 0.0347 and 0.0348 for (---). Thus, the (+++) was selected as correct for our specimen. A racemic solution of (III) crystallizes as a conglomerate from which a crystal we selected was found to be (+)(589)-trans-[Co(3,2,3-tet)(NO2)(2)]NO3 (III), CoO7N7C8H22. It crystallizes in the enantiomorphic space group, P2(1) with lattice constants a = 6.295(1) Angstrom, b = 15.108(3) Angstrom, c = 8.029(1) Angstrom, and beta = 100.28(2)degrees; V = 751.35 Angstrom(3) and d(calc. M.W. = 387.24, Z = 2) = 1.712 g cm(-3). A total of 2393 data were collected over the range of 4 degrees less than or equal to 2 theta less than or equal to 60 degrees; of these, 1869 (independent and with I greater than or equal to 3 sigma(I)) were used in the structural analysis. Data were corrected for absorption (mu = 11.859 cm(-1)), and the relative transmission coefficients ranged from 0.8814 to 0.9976. Refinement was carried out for both lattice enantiomorphs and the final R(F) and R(W)(F) residuals were, respectively, 0.0463 and 0.0482 for (+++) and 0.0441 and 0.0442 for (---). Thus, the latter was selected as correct for our specimen, and the final cycle of refinement with the (---) model converged to R(F) and R(W)(F) of 0.0436 and 0.0421. For all three compounds, the six-membered rings are chairs; the secondary nitrogens are chiral centers, and the five-membered rings are ordered and conformationally dissymmetric, as expected. Coincidentally, in (I), (II), and (III) the central rings are right-handed helices with delta(+50.0 degrees), delta(+53.3 degrees), and delta(+48.3 degrees), respectively. Thus, the secondary nitrogens of all three cations are (R), rendering the cations chiral. The incidence of conglomerate crystallization in trans coordination compounds is rare, and those known are asymmetrically substituted (see Ref. 4 for the four known cases). Thus, the incidence of such crystallization mode in a new series of [trans-Co(amine ligands)X(2)](+) cations bearing symmetrical pairs of trans ligands was an unexpected and welcomed event. In all three cases, the counteranions are bonded to the hydrogens of the terminal -NH2 moieties, thus forming an overall entity which resembles a macrocycle. In fact, parallels between the crystallization behavior of our compounds and that of macrocycles bearing related fragments is discussed. Finally, in the three compounds, homochiral cations are linked into infinite strings by hydrogen bonds between the axial ligands and amino hydrogens on adjacent cations of the string. In turn, strings are stitched together by the counteranions which form bonds with amino hydrogens on cations of adjacent strings.