Structures of Three Diastereomers of trans(N-Ph, N-Ph)-2,4-Pentanedionatobis(N-phenylethylenediamine)cobalt(III) and of One Diastereomer of trans(N-Ph, N-Ph)-Oxalatobis(N-phenylethylenediamine)cobalt(III) Complex Cations

Abstract

Abstract The molecular structures of three racemic pairs of diastereomers, ΔRR(ΛSS)-, ΔSR(ΛRS)-, and ΔSS(ΛRR)-trans(N-Ph, N-Ph)-[Co(pd)(Ph-en)2]2+ and of one racemic pair of diastereomers, ΔSS(ΛRR)-trans(N-Ph, N-Ph)-[Co(ox) (Ph-en)2]+ (pd=2,4-pentanedionate ion, ox=oxalate ion, Ph-en=N-phenylethylenediamine) were determined by the single-crystal X-ray diffraction method in order to study the intramolecular interactions between π-systems in the ligands. For the ΔSS(ΛRR)-isomer of [Co(pd)(Ph-en)2]2+, three kinds of crystal structures 3a, 3b, and 3c were investigated. The crystal data and final R values are: ΔRR(ΛSS)-[Co(pd)(Ph-en)2](ClO4)2·H2O (1), orthorhombic, Pbca, a=32.472(9), b=11.120(3), c=15.303(4) Å, V=5526(3) Å3, Z=8, R=0.065 for 2113 observed unique reflections. ΔSR(ΛRS)-[Co(pd)(Ph-en)2](ClO4)2 (2), orthorhombic, P212121, a=19.440(8), b=16.406(8), c=8.407(3) Å, V=2681(2) Å3, Z=4, R=0.038 for 2205 reflections. ΔSS(ΛRR)-[Co(pd)(Ph-en)2]Cl2·H2O (3a), monoclinic, P21⁄c, a=12.475(3), b=11.590(2), c=19.054(4) Å, β=117.18(2)°, V=2450.6(9) Å3, Z=4, R=0.035 for 2164 reflections. ΔSS(ΛRR)-[Co(pd)(Ph-en)2](ClO4)Cl·H2O (3b), triclinic, P\bar1, a=11.847(5), b=13.584(4), c=8.367(2) Å, α=103.57(2), β=91.85(3), γ=84.25(3)°, V=1302.1(8) Å3, Z=2, R=0.087 for 1374 reflections. ΔSS(ΛRR)-[Co(pd)(Ph-en)2](ClO4)Cl (3c), triclinic, P\bar1, a=11.660(5), b=14.028(3), c=8.308(7) Å, α=108.00(8), β=101.57(9), γ=92.47(13)°, V=1258(3) Å3, Z=2, R=0.052 for 1118 reflections. ΔSS(ΛRR)-[Co(ox)(Ph-en)2] Br·6H2O (4), orthorhombic, Pna21, a=15.804(1), b=15.646(1), c=10.428(2) Å, V=2578.5(4) Å3, Z=4, R=0.065 for 1496 reflectios. The numbers of phenyl rings of the Ph-en ligands that overlap with the pd π system in the complex cation are 0, 1, and 2 for 1, 2, and 3 respectively. The ox ligand of 4 is ill-sandwiched by the two phenyl rings, whereas the pd ligand is well-sandwiched in 3a. The arrangements of the phenyl groups relative to the pd differ slightly from one another in the crystals of 3a, 3b, and 3c. The dihedral angles between the pd (or ox) and phenyl rings range from 25 to 35°.