The crystal structure of (−)589-tris-[(+)-trans-1,2-diaminocyclopentane]cobalt(III) chloride tetrahydrate, (−)589-[Co(+cptn)3]Cl3.4H2O

Abstract

The crystal structure of (-)s89-tris-(+ trans-1,2-diaminocyclopentane)cobalt(IIl) chloride tetrahydrate, (-)589[Co(+cptn)3]C13.4H20, has been determined from three-dimensional data collected by a diffractometer. The structure was refined by the full-matrix least-squares method. Refinement was unusually difficult due to large correlation coefficients between parameters, associated with a non-orthogonality of the a and b axes. The final R index is 0.12 for 786 observed reflexions. Crystals are hexagonal with space group P6122. Lattice constants are a= 11.871, c= 30"803 A, with six formula units in the unit cell. The complex ion is mononuclear with pseudo-symmetry D3. Three ligands are bonded to the cobalt atom through six nitrogen atoms. The five-membered chelate rings are not planar. Their shape and size are similar to those of [Co(en)3] 3÷. The conformation of the chelate ring is '/el'. The cyclopentane rings take half-chair conformation. Some strain is introduced in the bond angles of the chelate ring due to fused-ring formation.A C 27B -10

The structure of trans-dichlorobis[(+)-(S,S)-trans-1,2-diaminocyclopentane]cobalt(III) chloride hydrochloride dihydrate, trans-[CoCl2{(+)-cptn}2]Cl.HCl.2H2O

“…The absolute configuration of (+)-cptn shown in Fig. 1 is in agreement with the results of Ito, Marumo & Saito (1971).…”

“…All of these complexes have 1,2-diamines as ligands and thereby form five-membered chelate rings. Of these complexes, those containing cptn, the present complex and (--) (Ito, Marumo & Saito, 1971). These distortions arise from the presence of the fused cyclopentane rings.…”

“…Description of the molecular structure and discussion (Ito, Marumo & Saito, 1971). This indicates that the five-membered chelate rings in the present trans-dichloro complex are flattened compared with those in the tris-chelate.…”

“…(Saito & Iwasaki, 1962), (-)589-/e13-[Co{(+)-cptn}3]Cl3.4H20 (Ito, Marumo & Saito, 1971), (+)589-ob3-[Co{ (-)-chxn }3]C13.H20 (Kobayashi, Marumo & Saito, 1972), and (-)ssg-lel3-lCo{(+)-chxn}3]C13.5H20 (Marumo, Utsumi & Saito, 1970), where en and chxn denote 1,2-diaminoethane and …”

Interplay of ligand chirality and metal configuration in mononuclear complexes and in a coordination polymer of Cr(iii)

“…When compared to the earlier reports concerning MIJchxn) 3 (ref. [14][15][16][17] and to the structural results for 1-4 discussed above, the stereochemistry at the metal in 7 is a surprise: it represents the first solid in which only the Λ configuration is encountered. The above mentioned preference for the Δ-RR configuration which was observed in ijMIJchxn) 3 ] 3+ cations and in 1-4 with two chxn ligands per metal is obviously no longer valid if only one enantiopure chelating ligand coordinates with the chromium center as in our complexes 6 and 7.…”