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Homochiral Cobalt Phosphonates Containing Δ‐Type Chains with a Tunable Interlayer Distance and a Field‐Induced Phase Transition
Author(s) -
Cai ZhongSheng,
Bao SongSong,
Ren Min,
Zheng LiMin
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201404611
Subject(s) - phosphonate , carboxylate , crystallography , monoclinic crystal system , metamagnetism , chemistry , alkyl , phase transition , cobalt , enantiomer , phase (matter) , type (biology) , stereochemistry , crystal structure , materials science , inorganic chemistry , condensed matter physics , magnetic field , magnetization , physics , organic chemistry , ecology , quantum mechanics , biology
Two pairs of enantiomeric Co II compounds with formulas [Co 2 (μ 3 ‐OH)(cyamp)(C n H 2 n +1 COO)] (cyampH 2 =( S )‐ or ( R )‐[(1‐cyclohexylethyl)amino]methylphosphonic acid; n =1 ( 1 ); n =7 ( 2 )) were synthesized. The structures of S ‐ 1 and S ‐ 2 were determined by single‐crystal structural analyses. Both crystallize in a monoclinic chiral space group P 2 1 , and exhibit layered structures in which the Δ‐type chains of corner‐sharing Co 3 (μ 3 ‐OH) triangles are connected by the phosphonate groups. The interlayer spaces are filled with the organic groups of the phosphonate and carboxylate ligands. Therefore, the distances between the layers can be manipulated by the length of the alkyl chain of the carboxylate ligands, from 14.6 Å in 1 to 20.0 Å in 2 . Magnetic studies were carried out for compounds S ‐ 1 and S ‐ 2 . Both show metamagnetism at low temperature. The critical field decreases with increasing interlayer distance from 8.18 kOe for S ‐ 1 to 7.01 kOe for S ‐ 2 at 1.8 K. The optical properties were also studied.