As materials science is moving towards the synthesis, the study and the processing of new materials exhibiting well-defined and complex functions, the synthesis of new multifunctional materials is one of the important challenges. One of these complex physical properties is magneto-chiral dichroism which arises, at second order, from the coexistence of spatial asymmetry and magnetization in a material. Herein we report the first measurement of strong magneto-chiral dichroism in an enantiopure chiral ferromagnet. The ab initio synthesis of the enantiopure chiral ferromagnet is based on an enantioselective self-assembly, where a resolved chiral quaternary ammonium cation imposes the absolute configurations of the metal centres within chromium-manganese two-dimensional oxalate layers. The ferromagnetic interaction between Cr(III) and Mn(II) ions leads to a Curie temperature of 7 K. The magneto-chiral dichroic effect is enhanced by a factor of 17 when entering into the ferromagnetic phase.

w, d(CH)], 1349 [vw, n(CN)], 1322 [vw, d(CH)], 1298 [vw, d(C±O±CH 2 ) [b]], 1196 [w, d(CO)], 1119 [m, n(C±C=O) [b]], 1053 [w, n(SiO)], 962 [w, n(WO)], 926 [w, n(WO)], 902 [w, n(WO)], 866 [w, n(WO)], 820 [w, n(WO)], 749 [w, n(WO)], 627 [vs, n(FeO)], 561 [vs, n(FeO)]. The BA ferrogels were prepared under the same conditions as the POM ferrogels but replacing POM by N,N¢-methylenebis(acrylamide) (BA) (0.017, 0.042, and 0.084 mol/L). The infrared data of a BA ferrogel with 0.017 M of BA and 5.5 % (volume fraction) of maghemite g-Fe 2 O 3 : IR (KBr): n = 1665 [s, n(CO) [a]], 1615 [s, d(NH)], 1448 [m, d(CH 2 )], 1414 [m, d(CH)], 1349 [m, n(CN)], 1322 [w, d(CH)], 1119 [vw, n(C±C=O) [b]], 627 [vs, n(FeO)], 561 [vs, n(FeO)]. Physical Measurements: The compound g-K 8 [SiW 10 O 36 ]×12H 2 O was prepared according to the literature [16]. Other reagents, [RSi(OMe) 3 ], and solvents were purchased from Aldrich and used as received. Elemental analyses were performed by the ªService central de microanalyses du CNRSº, Vernaison, France. The IR spectra (4000±250 cm ±1 ) were recorded on a Bio-Rad FTS 165 FTIR spectrometer with compounds and dried hydroferrogels sampled in KBr pellets. The volume fraction of magnetic particles in the different hydroferrogels and the particle sizes are deduced from magnetic measurements using a classical Foner device [17]. The rotational diffusion coefficient of particles is determined by the relaxation of birefringence. This method has already been described in the literature [15]. Transmission electron microscopy (TEM) (microscope JEOL 100 CX2) was performed on a microcoat of hydroferrogel deposited on a grid after microtomy. The gels are filmed with a charge coupled device (CCD) color camera (Vista, VPC 4130, UK). The degree of swelling of the hydroferrogel samples was characterized by the ratio m/m 0 , where m is the mass of the hydroferrogel sample swollen in aqueous solution and m 0 is the mass of the dry hydroferrogel.