The Structure of Dichloro(4-hydroxy-l-proline)cadmium(II)

Abstract

An X-ray diffraction study of the title complex has been carried out. The crystal is monoclinic, with the space group P21; Z=2; a=8.196(4), b=7.275(3), c=7.740(4) Å, β=103.73(4)° Full-matrix least-squares refinements have led to the final R value of 0.030. The structure consists of one-dimensional polymers bridged by chlorine atoms and a carboxyl group. Four chlorine atoms coordinate to a cadmium atom and form a square plane. The planes extend in the direction of the b axis like an infinite folding screen, sharing opposite edges. From the trough positions in the zigzag structure, the carboxyl oxygen atoms of 4-hydroxy-l-proline coordinate forkedly to two cadmium atoms. The ligand is a zwitter ion in the complex.

Synthesis, crystal growth and characterizations of bis (l-proline) cadmium iodide: a new semi-organic nonlinear optical material

“…The molecular geometry is similar to that observed in related amino acid containing compounds [19,[25][26][27].…”

Growth and characterization of dichlorobis l-proline Zn(II): A semiorganic nonlinear optical single crystal

“…Amino acids have two or more types of coordination atoms and can act as various bridging ligands [7][8][9][10]. Taking advantage of the properties of the amino acid ligands, an amino acid complex was used as a ligand in order to synthesize a new heteronuclear complex.…”

Characterization and crystal structure of cadmium(II) halide complexes with amino acids and their derivatives: VII. Crystal structures of aquadibromo(3-aminopropanoic acid)cadmium(II), dichloro(4-aminobutanoic acid)cadmium(II), diaquabis(aminohexanoic acid)cadmium(II) tetrachlorocadmium(II), and dibromo(azetidine-3-carboxylic acid)cadmium(II)

“…This structure is similar to that of [CdCl 2 -(Hsar)] [9], [CdBr 2 (DL-Hpipe-3)] [10], and [CdCl 2 (Hpipe-4)] [10], in which two carboxyl oxygen atoms are coordinated to the identical cadmium atom. However, this structure is different from those of [CdCl 2 (L-Hhpro)] [5], [CdCl 2 -(L-Hpro)](H 2 O) [6], [CdCl 2 (L-Hpipe-3)] [7], and [CdCl 2 (LHaze-2)](H 2 O) [8]. Because the bromine atom radius is larger than that of a chlorine atom, [CdBr 2 (Haze-3)] cannot exhibit the same structure as that of [CdCl 2 (L-Haze-2)](H 2 O) [8] in which a chlorine atom and a piperidine ring are comparatively near each other.…”

“…In this crystal, each pair of adjacent cadmium atoms have been triply bridged by two chlorine atoms and a syn-syn carboxylate group of a Hapro, resulting in one-dimensional polymer chains [14]. Such structure is very similar to that of [CdCl 2 (L-Hhpro)] [5]. As described above, carboxyl oxygen atoms may have various coordination types.…”

“…Dichloro(4-hydroxy-L-proline)cadmium(II) [CdCl 2 (L-Hhpro)] [5], dichloro(L-proline)cadmium(II) monohydrate [CdCl 2 (L-Hpro)](H 2 O) [6], dichloro(L-piperidine 3-carboxylic acid)cadmium(II) [CdCl 2 (L-Hpipe-3)] [7], and dichloro(L-azetidine-2-carboxylic acid)cadmium(II) monohydrate [CdCl 2 (L-Haze-2)]-(H 2 O) [8] have a one-dimensional polymer bridged by chlorine atoms and a carboxyl group, like an infinite folding screen. Dichloro(N-methylglycine)cadmium(II) [CdCl 2 (Hsar)] [9], dibromo(DL-piperidine-3-carboxylic acid)cadmium(II) [CdBr 2 (DL-Hpipe-3)] [10], and dichloro(piperidine-4-carboxylic acid)cadmium(II) [CdCl 2 (Hpipe-4)] [10] have a one-dimensional polymer bridged by two halogen atoms, and in these complexes two carboxyl oxygen atoms have ligated to the same atom and have made a four-membered chelate ring.…”