Controlled Binding of a l-Cysteinato Cobalt(III) Octahedron to a Cadmium(II) Center

Abstract

The binding ability of a chiral L-cysteinato cobalt(III) complex, [Co(L-cys-N,S)(en)2]+ (l-H2cys = L-cysteine, en = ethylenediamine), toward a cadmium(II) center, together with the construction of S-bridged CoIIICdII structures that are controlled by anions and pH, is reported. The reaction of Lambda(L)-[Co(L-Hcys-N,S)(en)2](ClO4)2 having a pendent COOH group with CdCl2 in a 1:1 ratio in water, followed by the addition of NaCl, gave an S-bridged CoIIICdII dinuclear complex, Lambda(L)-[CdCl4{Co(L-Hcys-N,S)(en)2}] (1Cl), in which a cadmium(II) ion is weakly coordinated by a thiolato group from a Lambda(L)-[Co(L-Hcys-N,S)(en)2]2+ unit, besides four Cl- anions. The corresponding 1:1 reaction with CdBr2 and NaBr yielded an S-bridged CoIIICdIICoIII trinuclear complex composed of an S-bridged CoIIICdIICoIII trinuclear cation and a [CdBr4]2- anion, (Lambda(L))2-[CdBr3{Co(L-Hcys-N,S)(en)2}{Co(L-cys-N,S)(en)2} ][CdBr4] (2), while a CoIIICdII dinuclear complex analogous to 1Cl, Lambda(L)-[CdBr4{Co(L-Hcys-N,S)(en)2}] (1Br), was obtained by the addition of HBr instead of NaBr. In the CoIIICdIICoIII cation of 2, a CdII center is very weakly coordinated by two thiolato groups from Lambda(L)-[Co(L-Hcys-N,S)(en)2]2+ and Lambda(L)-[Co(L-cys-N,S)(en)2]+ units, besides three Br- anions, with the trinuclear structure being sustained by an intramolecular COOH...OOC hydrogen bond. On the other hand, no S-bridged structure was obtained by the corresponding 1:1 reaction with CdI2 and NaI, giving only a mononuclear CoIII species with a [CdI4]2- counteranion, Lambda(L)-[Co(L-Hcys-N,S)(en)2][CdI4] (3). When Lambda(L)-[Co(L-cys-N,S)(en)2]ClO4 having a deprotonated pendent COO- group was reacted with CdCl2 in a 1:1 ratio in water, followed by the addition of NaCl, a one-dimensional (CoIIICdII)n polymeric complex, (Lambda(L))n-[CdCl3{Co(L-cys-N,S)(en)2}]n (4Cl), in which Lambda(L)-[Co(L-cys-N,S)(en)2]+ units are alternately linked by [CdCl3]- moieties through thiolato and carboxylate groups, was constructed. An analogous (CoIIICdII)n polymeric structure having [Cd(NCS-N)3]- moieties, (Lambda(L))n-[Cd(NCS-N)3{Co(L-cys-N,S)(en)2}]n (4NCS), was also produced by the use of Cd(ClO4)2 and NaSCN.

Controlling the dimensionalities and structures of homochiral Zn(ii) and Cd(ii) compounds of N-(p-tosyl)-S-carboxymethyl-l-cysteinevia tuning the connecting modes of metal ions and chiral linkers by different kinds of ancillary ligands

“…The Cd-O bond lengths (2.228(3) to 2.357(3) A ˚) and the Cd-S bond length (2.6635(10) A ˚) are within the normal range. [62][63][64][65][66] The O-Cd-O and O-Cd-S angles range from 72.81(6) to 172.04 (10) (Table 1). The two carboxylato groups of Ts-cmc in this complex present different coordination modes.…”

Fluorescent, Theoretical and Structural Investigations on [Me4bim][CdCl4] (Me4bim = 1,1′,3,3′-tetramethyl-2,2′-bi-1H-imidazolium)

“…The Cd-Cl bond distances are between 2.4677(6) Å and 2.4992(6) Å with a mean value of 2.4844(7) Å, which is comparable with data documented previously. [12][13][14][15] The dihedral angle of two anions, the charge of the Me 4 bim moiety should be +2, as in the cases found in the literature. [16][17][18][19][20] The Me 4 bim moieties are interconnected to the [CdCl 4 ] 2− anions via C-H•••Cl hydrogen bonds, yielding a supramolecule, as shown in Fig.…”

“…The Cd-Cl bond distances are between 2.4677(6) Å and 2.4992(6) Å with a mean value of 2.4844(7) Å, which is comparable with data documented previously. [12][13][14][15] The dihedral angle of two (7) Cl(2)-Cd(1)-Cl(4) 105.77(2) Cd(1)-Cl (2) 2.4677 (6) Cl (1) The solid-state emission spectra of 1 were measured at room temperature. The emission spectra of 1 are shown in Fig.…”

[N,N’-diethyl-4,4′-bipyridinium][CdX4] (X = Cl or Br) with N,N’-diethyl-4,4′-bipyridinium generated in situ: An Effective Route to Viologen Compounds

“…The bond lengths of Cd-Cl are 2.4415(7) and 2.4813(7) Å with an average value of 2.4614(7) Å, comparable with those reported previously. [8][9][10][11] The bond angles of Cl-Cd-Cl are in the range 97.63(4)°-115.05(3)°, close to that for one regular tetrahedron. Bond valence calculation showed that the cadmium atom is in a +2 oxidation state (Cd1: 2.143).…”