Two 3d-4f heterometallic coordination polymers {[Ln(PDA)3Mn1.5(H2O)3].3.25H2O}infinity with 1D channels were synthesized under hydrothermal conditions (PDA = pyridine-2,6-dicarboxylic acid; Ln = Eu (1); Ln = Tb (2)). The emission intensities of 1 and 2 increased significantly upon addition of Zn2+, while the introduction of other metal ions caused the intensity to be either unchanged or weakened. The case implies that 1 and 2 may be used as luminescent probes of Zn2+.

A nanotubular 3D heterometallic zeolitic polymer, {[Yb(PDA)3Mn1.5(H2O)3].1.5H2O}n (2), was designed and synthesized by simply tuning the amount of coordinated water on the Mn ion in the molecular ladder polymer {[Yb(PDA)3Mn1.5(H2O)6].6H2O}n (1). 1 and 2 were structurally and magnetically characterized. The water molecules capsulated within the nanotube were arrayed into an unprecedented "water" pipe. The robust 2 retained intact networks after the removal of guest water trapped in the nanotubes and even after methanol replaced guest water.

Interest in porous metal-coordination polymers that are constructed by self-assembly processes has mushroomed recently, [1] because of their use in, for example, redox catalysis, cathodic electrolysis, ion exchange, adsorption, separation, sensors, and molecular recognition. [2][3][4][5] However, much of the work has so far focused on coordination polymers containing transition metals, [2,6] while rare-earth metal compounds have received much less attention. [7] To date, no systematic investigation of zeolite-type structures containing metal atoms from the lanthanide series along with transitionmetal atoms has been documented. Furthermore, the pores or channels reported were mainly formed through either hydrogen bonding, [2b] or p-p packing, [1b] and only in a few cases were they formed through metal-ligand bonding alone.On the other hand, the construction of mesoporous metal--organic polymers suffers from difficulties in the control of the polymer dimensionality. Although ligands can be designed to create a large hole, the resulting coordination polymers are often plagued by lattice interpenetration, [8] or framework breakdown on removal of a guest molecule. [9] In addition, the variable and versatile coordination behavior of 4f-metal ions limits their selective introduction into highly ordered structures.Herein we report the syntheses and structures of three coordination polymers formed through hydrothermal synthesis: [{[Ln(dipic) 3 Mn 1.5 (H 2 O) 3 ]·n H 2 O} ¥ ], H 2 dipic = pyridine-2,6-dicarboxylic acid; Ln = Pr, n = 2 (1); Ln = Gd, n = 3.5 (2); Ln = Er, n = 3 (3). These compounds have the relatively large nanometer-sized tubes associated with selfassembly processes directed by metal-ligand coordination only, and the framework remains intact on removing water molecules trapped in the nanotube.The three compounds are stable in air and are insoluble in common solvents. Single-crystal X-ray diffraction analyses were performed on selected crystal of these compounds. The crystal structures of the polymers are isomorphous, comprising a 3D framework containing nine-coordinate lanthanidemetal centers and six-coordinate transition-metal centers, which results in a nanotubelike structure (Figure 1). All three polymers crystallized in the hexagonal crystal system, space group P6/mcc. The crystal structure is built up of two distinct types of building blocks, Ln(dipic) 3 and MnO 4 (H 2 O) 2 (Figure 2). The Ln atom is located at the intersection of a threefold and a twofold axis and is coordinated by three tridentate (ONO) dipic anions; for which each carboxy group coordinates through one oxygen atom. Three N atoms and six O atoms complete the coordination sphere of the Ln 3+ center, which conforms most closely to a tricapped trigonal prism. The coordination geometry around Mn 2+ center is a slightly distorted octahedron, the equatorial plane of which comprises four O atoms from the carboxy groups of the dipic molecules that are chelated to four neighboring Ln 3+ centers; two water molecules occupy the remaining apic...

Cadmium salts with different triazole ligands have led to a series of novel triazole-cadmium compounds varying from zero- to three-dimensionality. [Cd(2)(deatrz)(2)(H(2)O)Br(4)] (1) (deatrz = 3,5-diethyl-4-amino-1,2,4-triazole) is a zero-dimensional complex which uses a triazole ligand together with micro-OH(2) as bridges to form a 1D chain via hydrogen-bonding contacts. [[Cd(3)(deatrz)(2)Cl(6)(H(2)O)(2)].2H(2)O](n) (2), [[Cd(dmtrz)Cl(2)].1.5H(2)O](n)(3) (dmtrz = 3,5-dimethyl-1,2,4-triazole), and [[Cd(3)(deatrz)(4)Cl(2)(SCN)(4)].2H(2)O](n)(4) are polymeric 1D chains. 2 and 4 were constructed via trinuclear cadmium units bridged by triazole ligands and chloride atoms, while 3 consists of micro(2)-Cl, micro(3)-Cl, and triazole bridges, cross-linked by hydrogen bonding to give a 3D framework. [[Cd(3)(dmatrz)(4)(SCN)(6)]](n)(5) (dmatrz = 3,5-dimethyl-4-amino-1,2,4-triazole) shows a two-dimensional structure whose fundamental units are trinuclear metal cations bridged via triazole ligands. The complex [[Cd(dmtrz)(SCN)(2)]](n)(6) is the first three-dimensional example in N1,N2-didentate-bridged triazole-metal compounds. Six complexes exhibit six types of bridging modes of N1,N2-triazole in combination with single-atom bridges. 2, 4, and 5 are the unprecedented examples of polymeric chains and planes constructed via trinuclear metal ion clusters, whereas 3 is the first example of the micro(3)-Cl bridging mode in triazole-metal complexes. We have briefly discussed the variety of dimensionalities based on the tuning of different organic ligands and anions.

A series of novel two-dimensional (2D) and three-dimensional (3D) praseodymium coordination polymers, namely, {[Pr3(PDA)4(HPDA)(H2O)8] x 8H2O}n (2), {[Pr2(PDA)3(H2O)3] x H2O}n (3), {[Pr(PDA)(H2O)4] x ClO4}n (4), and { [Pr2(PDA)2(H2O)5SO4] x 2H2O}n (5) (PDA = pyridine-2,6-dicarboxylic anion), was designed and synthesized under hydrothermal conditions. Complexes 1-3 (chainlike polymer, {[Pr(PDA)(HPDA)(H2O)2] x 4H2O}n (1) was also obtained independently by us, although it has been reported recently by Ghosh et al.) were fabricated successfully by simply tuning the Pr/PDA ratio and exhibited various and intriguing topological structures from a 1D chain to a 3D network. While the synthetic strategy of 5 was triggered and further performed only after 1 was structurally characterized. The complexes were characterized by X-ray single-crystal determination, spectroscopic, and variable-temperature magnetic susceptibility analyses. In complex 2 an unusual nanosized square motif as a building block constructed by eight Pr ions was further assembled into a highly ordered 2D grid compound. In complex 3 the decanuclear Pr metal-based structure as a repeat unit interpenetrated to form a novel 3D polymer. Complex 4 was a 3D network polymer fabricated through a hexanuclear Pr ring as a building block, and ClO4- anions as guests were trapped in the cavity. In complex 5 six Pr atoms, two SO4(2-) anions, and carboxylic oxygen bridges constructed an intriguing rectangle structure as a repeat unit in the grid to form a 2D coordination polymer in which the unique bi-bidentate coordination mode of SO4(2-) anion was observed.

Two novel microporous metal-organic frameworks, {[Pr 3 (ATPT) 2 (HATPT) 4 ]‚(NO 3 )‚8H 2 O} n (1) and {[Nd 3 (ATPT) 3 (HATPT) 3 ]‚9H 2 O} n (2) (H 2 ATPT ) 2-aminoterephthalic acid), were synthesized by slow diffusion of aqueous solution of H 2 ATPT and Pr(NO 3 ) 3 ‚6H 2 O or Nd(NO 3 ) 3 ‚6H 2 O in 2-propanol. X-ray diffraction analyses reveal that their three-dimensional structures are composed of ATPT spacers and trinulcear lanthanide nodes, in which there are two crystallographically independent lanthanide atoms, nine-and twelve-coordinated. Twelve ATPT anions, adopting an unprecedented pentadentate η 1 :η 1 :η 1 :η 2 bridging coordination mode, ligate the trinuclear node. Each pair of ATPT anions acts as a double bridge and is considered as one connection. Thus each trinuclear core is connected to the six nearest Ln 3 neighbors forming a NaCl-type crystal lattice with a three-dimensional intersecting channel system of ca. 1.3-nm spacing between the centers of the adjacent clusters. The guest water molecules located in the large cavities can be removed without ruining the microporous framework. Thermal gravimetric and powder X-ray diffraction analyses confirm that small molecules, four methanol molecules per Pr 3 unit and six methanol molecules per Nd 3 unit, respectively, can be absorbed into the dehydrated microporous frameworks.

Two new coordination polymers {[Ln(2)(PDA)(6)Co(3)(H(2)O)(6)] x xH(2)O}(n) [Ln = Nd, x = 7 (1); Ln = Gd, x = 3.25 (2); H(2)PDA = pyridine-2,6-dicarboxylic acid] have been prepared under hydrothermal conditions with Ln(NO(3))(3) x 6H(2)O, CoO, and H(2)PDA in a molar ratio of 2:3:6. X-ray crystallographic analyses reveal that they crystallize in the hexagonal group P6/mcc and exhibit a nanotubular 3D framework. The adsorption experiment shows that 1 and 2 can adsorb radicals, which is proven by electron paramagnetic resonance spectra with the characteristic bands of the radicals at g = 2.006 and 2.005, respectively.

The first azide(mu1,1)-bridged binuclear cobalt(II) complex with a chelated imino nitroxide radical, [Co2(immepy)2(N3)(4)].2EtOH, was structurally and magnetically characterized, where immepy = 4,4,5,5-tetramethyl-2-(6'-methyl-2'-pyridyl) imidazoline-1-oxyl. Five nitrogen atoms complete the coordination sphere of the Co(II) ion, showing a distorted trigonal bipyramid geometry. Two N(3)(-) anions act as bridges between cobalt ions in the mu1,1 coordination mode, resulting in a binuclear structure with an inversion center. Magnetic studies show that ferromagnetic couplings occurred between the adjacent cobalt(II) ions through N3(-)(mu1,1)) bridges, and antiferromagnetic couplings between the cobalt(II) ions and organic radicals.