A new family of cyano-bridged coordination polymers Ln(H(2)O)(5)[M(CN)(8)] (Ln = Eu, Tb, Sm, Gd; M = Mo, W) were obtained and characterized by X-ray diffraction, photoluminescence spectroscopy, and magnetic analyses. These compounds are isomorphous and crystallize in the tetragonal system P4/nmm, forming two-dimensional gridlike networks. The Eu- and Tb-containing coordination polymers are room-temperature optically active emitters displaying the characteristic (5)D(0) --> (7)F(0-4) (Eu(3+)) and (5)D(4) --> (7)F(6-2) (Tb(3+)) transitions. All of the coordination polymers except Eu(H(2)O)(5)[M(CN)(8)] present long-range magnetic ordering at low temperatures. The coexistence of luminescence with ferromagnetic ordering for Tb(H(2)O)(5)[M(CN)(8)] (M = Mo, W) suggests that these compounds may be considered as bifunctional magneto-luminescent coordination polymers exhibiting diverse physical responses when subjected to various external stimuli.

A new cyano-bridged coordination polymer network Tb(H2O)5-[Mo(CN)8] was obtained and characterized. This compound has a two-dimensional layered structure and presents luminescence along with a magnetic transition at low temperature.

This article presents the first example of ultra-small (3-4 nm) magneto-luminescent cyano-bridged coordination polymer nanoparticles Ln0.33(3+)Gdx3+/[Mo(CN)8]3- (Ln=Eu (x=0.34), Tb (x=0.35)) enwrapped by a natural biocompatible polymer chitosan. The aqueous colloidal solutions of these nanoparticles present a luminescence characteristic of the corresponding lanthanides (5D0→7F0-4 (Eu3+) or the 5D4→7F6-2 (Tb3+)) under UV excitation and a green luminescence of the chitosan shell under excitation in the visible region. Magnetic Resonance Imaging (MRI) efficiency, i.e. the nuclear relaxivity, measurements performed for Ln0.33(3+)Gdx3+/[Mo(CN)8]3- nanoparticles show r1p and r2p relaxivities slightly higher than or comparable to the ones of the commercial paramagnetic compounds Gd-DTPA® or Omniscan® indicating that our samples may potentially be considered as a positive contrast agent for MRI. The in vitro studies performed on these nanoparticles show that they maybe internalized into human cancer and normal cells and well detected by fluorescence at the single cell level. They present high stability even at low pH and lack of cytotoxicity both in human cancer and normal cells.

Size controlled organic phase soluble cyano-bridged bimetallic coordination polymer nanoparticles made of M n+ and [M′(CN)6]3− (with M n+ = Mn2+, Ni2+, Fe2+, Eu3+, Tb3+, Sm3+ and M′ = Fe3+, Cr3+) were synthesized by using oleic acid and trialkylamines or a triarylamine as stabilizing agents. The obtained nanoparticles were studied by transmission electronic microscopy (TEM), infrared and electronic spectroscopy, X-ray diffraction, and magnetic measurements. These analyses revealed the formation of spherical metallic cyano-bridged nanoparticles with sizes in the range of 2–5 nm depending on the nature of the metal ion used. The magnetic studies of these colloidal solutions revealed the presence of a pure superparamagnetic regime for the nanoparticles based on [Cr(CN)6]3− and a collective regime caused by weak dipolar interparticle interactions for the nanoparticles based on [Fe(CN)6]3−.

T he design and study of multifunctional molecular materials exhibiting different physical properties have attracted a great deal of attention because of their fundamental interest and their potential applications. 1 Efforts have been focused on investigations of magnetoluminescent coordination polymers 2 and, in particular, those presenting luminescence in the near-infrared (NIR) region because of interesting applications in fields ranging from biomedical applications to telecommunications. 3 Along this line of thought, one of the promising families of coordination polymers is cyano-bridged networks in which the luminescent lanthanide ions are associated with nd (n = 3À5) cyanometallate building blocks in order to enhance magnetic anisotropy and magnetic interactions. 4 Indeed, numerous one-, two-, and threedimensional cyano-bridged compounds presenting mainly magnetic properties have been reported in the last 30 years, 5 but the luminescent properties of these compounds have rarely been exploited. 6 To the best of our knowledge, only two compounds based on an association of NIR-emissive lanthanides (Yb 3+ and Nd 3+ ) with cyanometallates have been reported, but the diamagnetism of the transition-metal ions results in the absence of magnetic interactions. 7 Our strategy to obtain magnetoluminescent materials relies on associating paramagnetic [M(CN) 8 ] 3À (M = Mo, W) building blocks (which do not act as luminescence quenchers, contrary to most of the hexacyanometallates) with an NIR-emissive Nd 3+ coordinated to an antenna ligand in order to enhance luminescence. In this Communication, we report the first examples of the NIR-emissive one-dimensional cyano- (Figures 1 and 2). Besides the common bridging cyanide group, while in compound 1 the Nd 3+ center is coordinated to two N,N 0 -chelated phenanthroline molecules and two DMF and one water solvent moieties (Figure 1c), in compounds 2 and 3, the coordination sphere is filled instead with DMF molecules (five in total) and only one phenanthroline molecule (Figure 2b).Because the five spatially close DMF molecules seem to impose a significant steric impediment around the Nd 3+ coordination environment, ∞ 1 [Nd(phen)(DMF) 5 W(CN) 8 ] (in 3) deviates more from linearity than that present in 1 (Figures 1a and 2a). Close packing of individual polymers to produce the crystal structures of 1À3 is clearly mediated by various supramolecular interactions, namely, close πÀπ contacts (Figures S1 and S2 in the SI) and OÀH 3 3 3 (N,O) hydrogen-bonding interactions. Because of the extra phenanthroline molecule in 1, the number of πÀπ contacts is also significantly higher than that in 2 and 3, with offset contacts occurring parallel to both the a and b axes of the unit cell ( Figure S1 in the SI). In addition, the

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A new family of mixed-lanthanide cyano-bridged coordination polymers Ln(0.5)Ln'(0.5)(H(2)O)(5)[W(CN)(8)] (where Ln/Ln' = Eu(3+)/Tb(3+), Eu(3+)/Gd(3+), and Tb(3+)/Sm(3+)) containing two lanthanide and one transition metal ions were obtained and characterized by X-ray diffraction, photoluminescence spectroscopy, magnetic analyses, and theoretical computation. These compounds are isotypical and crystallize in the tetragonal system P4/nmm forming two-dimensional grid-like networks. They present a magnetic ordering at low temperature and display the red Eu(3+) ((5)D(0) → (7)F(0-4)) and green Tb(3+) ((5)D(4) → (7)F(6-2)) characteristic photoluminescence. The Tb(0.5)Eu(0.5)(H(2)O)(5)[W(CN)(8)] compound presents therefore green and red emission and shows Tb(3+)-to-Eu(3+) energy transfer.