Homochiral Column Structure ofrac- and Λ-Tris(ethylenediamine)cobalt(III) Cyclotriphosphate Dihydrate in Crystal Structures and Cation−Anion Association in Aqueous Solution

Abstract

rac- and Lambda-tris(ethylenediamine)cobalt(III) cyclotriphosphate dihydrate with the chemical formulas rac-[Co(en)(3)]P(3)O(9).2H(2)O (1) and Lambda-[Co(en)(3)]P(3)O(9).2H(2)O (2) were synthesized, and their crystal structures were determined by single-crystal X-ray analyses. In 1, the cationic complex molecule [Co(en)(3)](3+) with the Delta or Lambda enantiomer and cyclotriphosphate anion are alternately arrayed and connected by multiple hydrogen bonds to form a homochiral column structure. Adjacent homochiral columns with different chirality for 1 are connected by intercolumn hydrogen bonds through P(3)O(9)(3)(-) anions, as the bridging groups, to form a tetrameric cyclic cylindrical structure, while the adjacent columns with the same chirality are connected for 2 to form the cyclic cylindrical structure. All 6 amino groups per [Co(en)(3)](3+) participate in the formation of 12 hydrogen bonds, in which 8 hydrogen bonds contribute to the construction of a homochiral column and the remaining 4 hydrogen bonds contribute to the intercolumn interactions. The circular dichroism spectrum of the aqueous solution of Lambda-[Co(en)(3)](3+) changes drastically when excess P(3)O(9)(3)(-) is added, and this change is explained by ion-pair formation. The thermodynamic association constant of [Co(en)(3)](3+) with P(3)O(9)(3)(-), calculated from the conductivity data, was log K = 4.26 at 25 degrees C.

Tetranuclear [Rh4(μ-PyS2)2(diolefin)4] Complexes as Building Blocks for New Inorganic Architectures: Synthesis of Coordination Polymers and Heteropolynuclear Complexes with Electrophilic d8and d10Metal Fragments

“…and P 3 O 9 3anions with the Λ or ∆ enantiomer. 20 Characterization and properties of the coordination polymers. The compounds 5-12 exhibit a weak electric conductivity in the solid state.…”

Tris(ethylenediamine)cobalt(III) nonaiododibismuthate

“…For (I), the average terminal Bi-I distance is 2.987 Å , the average bridging Bi-I distance is 3.282 Å , and the cis angles range from 75.12 (2) to 98.75 (2) . Likewise, the [Co(en) 3 ] 3+ cation is well known (Wang et al, 2004;Nakashima et al, 2003), and the bond distances and angles of the cation in (I) are within the expected ranges (Table 1). , where it is observed that columns of the cations alternate with columns of the anions in a chessboard fashion.…”

XAS examination of glutathione–cobalt complexes in solution

“…It was claimed that for cobalt, the coordination to the glutamic moiety (N1O1) occurred first, followed by thiol coordination, together with deprotonation of the Glu-Cys amide nitrogen (N2) at high pH. Co(III)-N amine bond lengths in mononuclear octahedral Co(III) solid crystallized complexes containing polyamino and/or aminothiol ligands ranged between 1.92 and 2.05 Å taking into account sulfur trans effect [59][60][61][62][63]. In Co:GSH pH12 , the Co-N1 distance (Table 1) was probably lengthened due to the same effect.…”