Adjusting the structures of lanthanide(III) complexes by variation of the metal sources: From a 2D (32.4)(34.43.52.65.7) layer to an unusual 3D (412.63)(49.66) nia network

Coordination Properties of Hydroxyisophthalic Acids: Topological Correlations, Synthesis, Structural Analysis, and Properties of New Complexes

Hydroxyisophthalic acids are valuable polytopic ligands for the design of functional materials based on coordination polymers due to the variety of charges and coordination modes they possess. Herein, we describe the synthesis, thermal stability, nonlinear optical (NLO) and spectroscopic properties of five novel coordination compounds, [K₂ L(H₂ O)₂ ], [MgL(H₂ O)₂ ] ⋅ 3H₂ O, [CaL(H₂ O)₃ ], [SrL(H₂ O)₃ ] ⋅ H₂ O, [BaL(H₂ O)(H₂ O)₅ ], and one salt, (NH₄ )₂ L ⋅ 2H₂ O, with 4,5,6-trihydroxyisophthalic acid (H₂ L), which has not been tested in assembling crystalline coordination networks before. The peculiarities of the structural organization of the compounds were analyzed and compared with those for other hydroxyisophthalates. The coordination properties of hydroxyisophthalic acids were studied from the topological point of view, and a comparative topological analysis of coordination and H-bonded networks was performed. Structural correlations revealed in this study could be useful for the design of hydroxyisophthalate-based coordination networks, including porous metal-organic frameworks, proton conductors, and NLO materials.

Dielectric transitions and relaxations in Ca(ii)Co(iii)-based cyanometallate frameworks with a rare (6,6)-connected nia topology

A series of cyanometallate frameworks A[CaCo(CN)₆] (A = protonated guanidine, urea or thiourea guest) exhibit a rare (6,6)-connected nia topology with the Schläfli symbol of (4¹²·6³)(4⁹·6⁶) and thermally driven dielectric transitions and relaxations without evident structural phase transitions.

Poly[[nona-aqua-bis-(μ-5-hy-droxy-benzene-1,3-di-carboxyl-ato)(5-hy-droxy-benzene-1,3-di-carboxyl-ato)dicerium(III)] hexa-hydrate]

In the title coordination polymer, {[Ce₂(C₈H₄O₅)₃(H₂O)₉]·6H₂O}_n, the asymmetric unit is formed by two Ce^III atoms, three 5-hy­droxy­benzene-1,3-di­carboxyl­ate ligands, nine coordinating water mol­ecules and six water mol­ecules of crystallization. The two Ce^III atoms are bridged by 5-hy­droxy­benzene-1,3-di­carboxyl­ate ligands acting in a bis-bidentate coordination mode, generating infinite chains along [101]. Both independent metal atoms are nine-coordinated, one by four O atoms from the carboxyl­ate groups of two bridging 5-hy­droxy­benzene-1,3-di­carboxyl­ate ligands and five O atoms from water mol­ecules, generating a tricapped trigonal–prismatic geometry. The coordination around the second Ce^III atom is similar, except that one of the water mol­ecules is replaced by an O atom from an additional 5-hy­droxy­benzene-1,3-di­carboxyl­ate ligand acting in a monodentate coordination mode and forming a capped square-anti­prismatic geometry.

Three new europium(III) methanetriacetate metal-organic frameworks: the influence of synthesis on the product topology

Three new metal-organic framework structures containing EuIIIand the little explored methanetriacetate (C7H7O63−, mta3−) ligand have been synthesized. Gel synthesis yields a two-dimensional framework with the formula [Eu(mta)(H2O)3]n·2nH2O, (I), while two polymorphs of the three-dimensional framework material [Eu(mta)(H2O)]n·nH2O, (II) and (III), are obtained through hydrothermal synthesis at either 423 or 443 K. Compounds (I) and (II) are isomorphous with previously reported GdIIIcompounds, but compound (III) constitutes a new phase. Compound (I) can be described in terms of dinuclear [Eu2(H2O)4]6+units bonded through mta3−ligands to form a two-dimensional framework with topology corresponding to a (6,3)-connected binodal (43)(466683)-kgdnet, where the dinuclear [Eu2(H2O)4]6+units are considered as a single node. Compounds (II) and (III) have distinct three-dimensional topologies, namely a (41263)(4966)-nianet for (II) and a (41065)(41164)-K2O2; 36641net for (III). The crystal density of (III) is greater than that of (II), consistent with the increase of temperature, and thereby autogeneous pressure, in the hydrothermal synthesis.