Homochiral Cobalt Phosphonates Containing Δ‐Type Chains with a Tunable Interlayer Distance and a Field‐Induced Phase Transition |
| |
Authors: | Zhong‐Sheng Cai Dr Song‐Song Bao Min Ren Prof Dr Li‐Min Zheng |
| |
Institution: | State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (P. R. China) |
| |
Abstract: | Two pairs of enantiomeric CoII compounds with formulas Co2(μ3‐OH)(cyamp)(CnH2n+1COO)] (cyampH2=(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 P21, and exhibit layered structures in which the Δ‐type chains of corner‐sharing Co3(μ3‐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. |
| |
Keywords: | cobalt homochirality metamagnetism optical properties phosphonates |
|