Hybrid molecular-based magnets containing organic NLO chromophores: A search toward an interplay between magnetic and NLO behavior

A new hybrid molecular-based ferromagnet of formula [(dmaph)PPh3] [MnCr(ox) (3)], where [(dmaph)PPh3](+) stands for the (4-dimethylaminophenyl)tripheny lphosphonium cation (ox(2)-being the oxalate anion), has been synthesized. It crystallizes in the monoclinic P2(1) space group, with lattice parameter s a 13.954(2) Angstrom, b = 16.297(2) Angstrom, c 14.323(2) Angstrom and be ta 99.27(1)degrees. Refinement based on F-0(2) yields R = 0.072 and wR(2) = 0.156. The compound exhibits a ferromagnetic interaction between Cr3+ and Mn2+, with a long-range magnetic ordering at T-C = 4.5 K. The hyperpolariza bility (beta) of the cation is calculated within the framework of the INDO/ SOS-based method, which indicates a beta value comparable to that of p-nitr oaniline for an absorption maximum at 306 nm (epsilon (max) = 28 500 M-1 cm (-1)). This result is consistent with the observation of a SHG efficiency 4 times that of urea for the parent [(dmaph)PPh3]Br salt, at 1.907 mum. The non-centrosymmetric [(dmaph)PPh3] [(MnCrIII)-Cr-II(ox)(3)] derivative is us ed as a model compound for an investigation of the potential effect of a fe rromagnetic ordering on the bulk NLO response of hybrid materials made of N LO cations inserted between magnetic anionic layers.