Search

Three principal factors may influence the final structure of coordination polymers (CPs): (i) the nature of the ligand, (ii) the type and coordination number of the metal center, and (iii) the reaction conditions. Further, flexible carboxylate aliphatic ligands have been widely employed as building blocks for designing and synthesizing CPs, resulting in a diverse array of materials with exciting architectures, porosities, dimensionalities, and topologies as well as an increasing number of properties and applications. These ligands show different structural features, such as torsion angles, carbon backbone number, and coordination modes, which affect the desired products and so enable the generation of polymorphs or crystalline phases. Additionally, due to their large coordination numbers, using 4f and 5f metals as coordination centers combined with aliphatic ligands increases the possibility of obtaining different crystal phases. Additionally, by varying the synthetic conditions, we may control the production of a specific solid phase by understanding the thermodynamic and kinetic factors that influence the self-assembly process. This revision highlights the relationship between the structural variety of CPs based on flexible carboxylate aliphatic ligands and f-elements (lanthanide and actinides) and their outstanding luminescent properties such as solid-state emissions, sensing, and photocatalysis. In this sense, we present a structural analysis of the CPs reported with the oxalate ligand, as the one rigid ligand of the family, and other flexible dicarboxylate linkers with –CH2– spacers. Additionally, the nature of the luminescence properties of the 4f or 5f-CPs is analyzed, and finally, we present a novel set of CPs using a glutarate-derived ligand and samarium, with the formula [2,2′-bipyH][Sm(HFG)2 (2,2′-bipy) (H2O)2]•(2,2′-bipy) (α-Sm) and [2,2′-bipyH][Sm(HFG)2 (2,2′-bipy) (H2O)2] (β-Sm). [ABSTRACT FROM AUTHOR]

Menezesite, ideally [Ba.sub.2]Mg[Zr.sub.4]([Ba[Nb.sub.12][O.sub.42]) *12[H.sub.2]O, occurs as a rug mineral in the contact zone between dolomite carbonatite and 'jacupirangite' (=a pyroxenite) at the Jacupiranga mine, in Cajati county, Sao Paulo state, Brazil, associated with dolomite, calcite, magnetite, clinohumite, phlogopite, ancylite-(Ce), strontianite, pyrite, and tochilinite. This is also the type locality for quintinite-2H. The mineral forms rhombododecahedra up to 1 mm, isolated or in aggregates. Menezesite is transparent and displays a vitreous luster; it is reddish brown with a white streak. It is non-fluorescent. Mohs hardness is about 4. Calculated density derived from the empirical formula is 4.181 g/[cm.sup.3]. It is isotropic, [n.sub.means]> 1.93(1) (white light); [n.sub.calc] = 2.034. Menezesite exhibits weak anomalous birefringence. The empirical formula is [([Ba.sub.147][K.sub.0.53][Ca.sub.0.31][Ce.sub.0.17] [Nd.sub.0.10][Na.sub.0.06][La.sub.0.02]).sub.[SIGMA]2.66] [([Mg.sub.0.94][Mn.sub.0.23][Fe.sub.0.3] [Al.sub.0.03]).sub.[SIGMA]1.43]([[Zr.sub.2.75] [Ti.sub.0.96][Th.sub.0.29).sub.[SIGMA]4.00 [[([Ba.sub.0.72][Th.sub.0.26][U.sub.0.02]).sub.[SIGMA]1.00] [([Nb.sub.9.23][Ti.sub.2.29][Ta.sub.0.36] [Si.sub.0.12]).sub.[SIGMA]12.00][O.sub.42]*12[H.sub.2]O. The mineral is cubic, space group Im [bar.3] (204), a = 13.017(1) [Angstrom], V = 2206(1) [[Angstrom].sup.3] Z = 2. Menezesite is isostructural with the synthetic compound [Mg.sub.7][Mg[W.sub.12][O.sub.42]][(OH).sub.4]*8[H.sub.2]O. The mineral was named in honor of Luiz Alberto Dias Menezes Filho (born 1950), mining engineer, mineral collector and merchant. Both the description and the name were approved by the CNMMN-IMA (Nomenclature Proposal 2005-023). Menezesite is the first natural heteropolyniobate. Heteropolyanions have been employed in a range of applications that include virus-binding inorganic drugs (including the AIDs virus), homogeneous and heterogeneous catalysts, electro-optic and electrochromic materials, metal and protein binding, and as building blocks for nanostructuring of materials. Keywords: Menezesite, new mineral, polyoxometalates, heteropolyniobate, heteropolyanions, crystal structure, chemical composition, Jacupiranga mine, Cajati, Brazil

Matioliite, ideally NaMg[Al.sub.5][(P[O.sub.4]).sub.4][(OH).sub.6] x 2[H.sub.2]O, occurs as a secondary hydrothermal mineral in the Gentil mine granite pegmatite, Mendes Pimentel Co., Minas Gerais, Brazil. Some crystals are zoned to more Fe-rich compositions with an [Fe.sup.2+]:Mg ratio of approximately 1:1, corresponding to an intermediate member of the burangaite-matioliite solid-solution series. Matioliite is intimately associated with fluorapatite, crandallite, and zoned gormanite-souzalite cystals. The mineral forms prismatic to tabular crystals, up to 1 mm long. Matioliite is transparent and displays a vitreous luster; it is blue to colorless with a white streak. It is non-fluorescent. Mohs hardness is about 5. Calculated density is 2.948 g/[cm.sup.3]. Matioliite is biaxial negative, [[eta].sub.[alpha]] = 1.597(2), [[eta].sub.[beta]] = 1.627(2), [[eta].sub.[gamma]] = 1.632(1) (white light), 2V (meas.) = 43(2)[degrees], 2V (calc.) = 44[degrees], dispersion r > v, orientation X = b, Z ^ c = 6[degrees]. Pleochroism is Y > X > Z, X = light blue to colorless, Y = blue, Z = colorless. The empirical formula is [([Na.sub.0.94][Ca.sub.0.01]).sub.[summation]0.95 [([Mg.sub.0.88][Fe.sup.2+.sub.0.11][Mn.sub.0.01].sub.[summation]1.00] [([Al.sub.4.84][Fe.sup.3+.sub.0.13]).sub.[summation]4.97] [(P[O.sub.4]).sub.4.03][(OH).sub.5.76] x 2[H.sub.2]O. The mineral is monoclinic, space group C2/c, a = 25.075(1) [Angstrom], b = 5.0470(3) [Angstrom], c = 13.4370(7) [Angstrom], [beta] = 110.97(3)[degrees], V = 1587.9(4) [[Angstrom].sup.3], Z = 4. Crystal-structure determination was carried out and showed it is isostructural with burangaite, dufrenite, and natrodufrenite. Both the description and the name were approved by the CNMMN-IMA (Nomenclature Proposal 2005-011). The 'magnesium analog of burangaite' described from the Gold Quarry mine, Carlin-trend, Eureka County, Nevada; 'burangaite' from Hochgosch, Millstatter See-Rucken, Karnten, Austria; and 'burangaite' described from Corrego Pomarolli, Linopolis, Divino das Laranjeiras, Minas Gerais, Brazil, are probably matioliite. Keywords: Matioliite, new mineral, crystal structure, burangaite, chemical composition, Gentil mine, Mendes Pimentel, Brazil