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Crystal structures of coordination polymers from CaI2 and proline.

Lamberts K, Englert U - Acta Crystallogr E Crystallogr Commun (2015)

Bottom Line: Completing our reports concerning the reaction products from calcium halides and the amino acid proline, two different solids were found for the reaction of l- and dl-proline with CaI2.In both structures, the iodide ions remain non-coordinating and hydrogen bonds are formed between these counter-anions, the amino groups, coordinating and co-crystallized water mol-ecules.While the overall composition of (1) and (2) is in line with other structures from calcium halides and amino acids, the diversity of the carboxyl-ate coordination geometry is quite surprising.

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Affiliation: Institute of Inorganic Chemistry, RWTH Aachen, Landoltweg 1, 52074 Aachen, Germany.

ABSTRACT
Completing our reports concerning the reaction products from calcium halides and the amino acid proline, two different solids were found for the reaction of l- and dl-proline with CaI2. The enanti-opure amino acid yields the one-dimensional coordination polymer catena-poly[[aqua-μ3-l-proline-tetra-μ2-l-proline-dicalcium] tetra-iodide 1.7-hydrate], {[Ca2(C5H9NO2)5(H2O)]I4·1.7H2O} n , (1), with two independent Ca(2+) cations in characteristic seven- and eightfold coordination. Five symmetry-independent zwitterionic l-proline mol-ecules bridge the metal sites into a cationic polymer. Racemic proline forms with Ca(2+) cations heterochiral chains of the one-dimensional polymer catena-poly[[di-aquadi-μ2-dl-proline-calcium] diiodide], {[Ca(C5H9NO2)2(H2O)2]I2} n , (2). The centrosymmetric structure is built by one Ca(2+) cation that is bridged towards its symmetry equivalents by two zwitterionic proline mol-ecules. In both structures, the iodide ions remain non-coordinating and hydrogen bonds are formed between these counter-anions, the amino groups, coordinating and co-crystallized water mol-ecules. While the overall composition of (1) and (2) is in line with other structures from calcium halides and amino acids, the diversity of the carboxyl-ate coordination geometry is quite surprising.

No MeSH data available.


The asymmetric unit of (1). Displacement ellipsoid are shown at the 80% probability level.
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fig1: The asymmetric unit of (1). Displacement ellipsoid are shown at the 80% probability level.

Mentions: Compound (1) crystallizes in the chiral ortho­rhom­bic space group P212121 with two calcium cations, five proline ligands, one coordinating water ligand, 1.7 non-coordinating water mol­ecules and four iodide anions in the asymmetric unit; all constituents are necessarily located in general positions (Fig. 1 ▶).


Crystal structures of coordination polymers from CaI2 and proline.

Lamberts K, Englert U - Acta Crystallogr E Crystallogr Commun (2015)

The asymmetric unit of (1). Displacement ellipsoid are shown at the 80% probability level.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4459365&req=5

fig1: The asymmetric unit of (1). Displacement ellipsoid are shown at the 80% probability level.
Mentions: Compound (1) crystallizes in the chiral ortho­rhom­bic space group P212121 with two calcium cations, five proline ligands, one coordinating water ligand, 1.7 non-coordinating water mol­ecules and four iodide anions in the asymmetric unit; all constituents are necessarily located in general positions (Fig. 1 ▶).

Bottom Line: Completing our reports concerning the reaction products from calcium halides and the amino acid proline, two different solids were found for the reaction of l- and dl-proline with CaI2.In both structures, the iodide ions remain non-coordinating and hydrogen bonds are formed between these counter-anions, the amino groups, coordinating and co-crystallized water mol-ecules.While the overall composition of (1) and (2) is in line with other structures from calcium halides and amino acids, the diversity of the carboxyl-ate coordination geometry is quite surprising.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Inorganic Chemistry, RWTH Aachen, Landoltweg 1, 52074 Aachen, Germany.

ABSTRACT
Completing our reports concerning the reaction products from calcium halides and the amino acid proline, two different solids were found for the reaction of l- and dl-proline with CaI2. The enanti-opure amino acid yields the one-dimensional coordination polymer catena-poly[[aqua-μ3-l-proline-tetra-μ2-l-proline-dicalcium] tetra-iodide 1.7-hydrate], {[Ca2(C5H9NO2)5(H2O)]I4·1.7H2O} n , (1), with two independent Ca(2+) cations in characteristic seven- and eightfold coordination. Five symmetry-independent zwitterionic l-proline mol-ecules bridge the metal sites into a cationic polymer. Racemic proline forms with Ca(2+) cations heterochiral chains of the one-dimensional polymer catena-poly[[di-aquadi-μ2-dl-proline-calcium] diiodide], {[Ca(C5H9NO2)2(H2O)2]I2} n , (2). The centrosymmetric structure is built by one Ca(2+) cation that is bridged towards its symmetry equivalents by two zwitterionic proline mol-ecules. In both structures, the iodide ions remain non-coordinating and hydrogen bonds are formed between these counter-anions, the amino groups, coordinating and co-crystallized water mol-ecules. While the overall composition of (1) and (2) is in line with other structures from calcium halides and amino acids, the diversity of the carboxyl-ate coordination geometry is quite surprising.

No MeSH data available.