Supramolecular Assemblies Built of [Nb₆Cl₁₂(CN)₆]^4- Octahedral Metal Clusters and [Mn(<i>a</i><i>cacen</i>)]⁺ Complexes

Reactions between solutions of [Me4N]4[Nb6Cl12(CN)6]·2MeOH and [Mn(L)]Cl (L = acacen2- = bis(acetylacetonato)ethylenediamine at room temperature led to the formation of four compounds containing supramolecular assemblies formed of [Nb6Cl12(CN)6]4- and [Mn(L)]+ as building units. The four compounds were characterized by single-crystal X-ray diffraction, IR, elemental analysis, thermogravimetric analysis, and magnetic susceptibility measurements (for 3). In 1, each cluster is coordinated by one [Mn(L)(MeOH)]+ via a CN- ligand to give an anionic dimeric unit {[Mn(L)(MeOH)][Nb6Cl12(CN)6]}3-, which connect to each other via hydrogen bonding between the CN- ligand and MeOH from the cations [Mn(L)(MeOH)2]+ to give anionic tubular-like chains. The structure of 2 comprises trimeric units {[Mn(L)(H2O)]2[Nb6Cl12(CN)6]}2- in which each cluster is trans-coordinated by two [Mn(L)(H2O)]+ cations via the CN- ligand. The trimeric units are connected to each other via hydrogen bonding between CN- and the water of coordination to give anionic chains along the crystallographic a axis. The chains are connected to each other through further hydrogen bonding to give an overall three-dimensional hydrogen-bonded framework. In 3, each cluster is coordinated by two [Mn(L)(MeCN)]+ and two [Mn(L)(H2O)]+ via CN- ligand to give neutral pentameric units that are connected through hydrogen bonding between CN- and aqua ligands to give hydrogen-bonded chains along the crystallographic b axis. 4 is based on two supramolecular ions; the cation consists of a heptameric unit {[Mn(L)(H2O)]4[Mn(L)]2[Nb6Cl12(CN)6]}2+ in which each cluster is coordinated by six [Mn(L)]+ via CN- ligand, whereas the anion {[Mn(L)]2[Nb6Cl12(CN)6]}2- is the same as that found in 2. Electrostatic interactions and hydrogen bonding between these two supramolecular species afford a 1D framework. Magnetic susceptibility shows that 3 is paramagnetic with four high-spin Mn(III) ions. Thermal behaviors of 1−4 are presented

Supramolecular Assemblies Built of [Nb₆Cl₁₂(CN)₆]^4- Octahedral Metal Clusters and [Mn(<i>a</i><i>cacen</i>)]⁺ Complexes

Reactions between solutions of [Me4N]4[Nb6Cl12(CN)6]·2MeOH and [Mn(L)]Cl (L = acacen2- = bis(acetylacetonato)ethylenediamine at room temperature led to the formation of four compounds containing supramolecular assemblies formed of [Nb6Cl12(CN)6]4- and [Mn(L)]+ as building units. The four compounds were characterized by single-crystal X-ray diffraction, IR, elemental analysis, thermogravimetric analysis, and magnetic susceptibility measurements (for 3). In 1, each cluster is coordinated by one [Mn(L)(MeOH)]+ via a CN- ligand to give an anionic dimeric unit {[Mn(L)(MeOH)][Nb6Cl12(CN)6]}3-, which connect to each other via hydrogen bonding between the CN- ligand and MeOH from the cations [Mn(L)(MeOH)2]+ to give anionic tubular-like chains. The structure of 2 comprises trimeric units {[Mn(L)(H2O)]2[Nb6Cl12(CN)6]}2- in which each cluster is trans-coordinated by two [Mn(L)(H2O)]+ cations via the CN- ligand. The trimeric units are connected to each other via hydrogen bonding between CN- and the water of coordination to give anionic chains along the crystallographic a axis. The chains are connected to each other through further hydrogen bonding to give an overall three-dimensional hydrogen-bonded framework. In 3, each cluster is coordinated by two [Mn(L)(MeCN)]+ and two [Mn(L)(H2O)]+ via CN- ligand to give neutral pentameric units that are connected through hydrogen bonding between CN- and aqua ligands to give hydrogen-bonded chains along the crystallographic b axis. 4 is based on two supramolecular ions; the cation consists of a heptameric unit {[Mn(L)(H2O)]4[Mn(L)]2[Nb6Cl12(CN)6]}2+ in which each cluster is coordinated by six [Mn(L)]+ via CN- ligand, whereas the anion {[Mn(L)]2[Nb6Cl12(CN)6]}2- is the same as that found in 2. Electrostatic interactions and hydrogen bonding between these two supramolecular species afford a 1D framework. Magnetic susceptibility shows that 3 is paramagnetic with four high-spin Mn(III) ions. Thermal behaviors of 1−4 are presented

Octahedral Niobium Chloride Clusters as Building Blocks of Templated Prussian Blue Framework Analogues

The preparation, structure, and magnetic properties of the first three-dimensional framework containing octahedral niobium cyanochloride clusters as building units are reported. Reactions of aqueous solutions of (Me4N)2K2[Nb6Cl12(CN)6] (2) with aqueous solutions of MnCl2 result in the precipitation of the compound (Me4N)2[MnNb6Cl12(CN)6] (3). The structure of 3 was determined from single-crystal X-ray diffraction study (crystal data:  cubic, Fm3̄m (No. 225), a = 15.513(4) Å, V = 3733.2(12) Å3, Z = 4). Its 3D framework is based on edge-bridged [Nb6Cl12]2+ clusters and Mn2+ ions bridged by cyanide ligands to form a cfc lattice [MnNb6Cl12(CN)6]2- in which all tetrahedral sites are occupied by the cations (Me4N)+ which act as charge compensating template. The structure of 3 can be considered as an expansion of the Prussian blue framework in which [Fe(CN)6]4- is replaced by the cluster [Nb6Cl12(CN)6]4-. Magnetic susceptibility measurements indicate that Mn2+ is present in a high spin d5 configuration. No magnetic ordering is observed

Octahedral Niobium Chloride Clusters as Building Blocks of Templated Prussian Blue Framework Analogues

The preparation, structure, and magnetic properties of the first three-dimensional framework containing octahedral niobium cyanochloride clusters as building units are reported. Reactions of aqueous solutions of (Me4N)2K2[Nb6Cl12(CN)6] (2) with aqueous solutions of MnCl2 result in the precipitation of the compound (Me4N)2[MnNb6Cl12(CN)6] (3). The structure of 3 was determined from single-crystal X-ray diffraction study (crystal data:  cubic, Fm3̄m (No. 225), a = 15.513(4) Å, V = 3733.2(12) Å3, Z = 4). Its 3D framework is based on edge-bridged [Nb6Cl12]2+ clusters and Mn2+ ions bridged by cyanide ligands to form a cfc lattice [MnNb6Cl12(CN)6]2- in which all tetrahedral sites are occupied by the cations (Me4N)+ which act as charge compensating template. The structure of 3 can be considered as an expansion of the Prussian blue framework in which [Fe(CN)6]4- is replaced by the cluster [Nb6Cl12(CN)6]4-. Magnetic susceptibility measurements indicate that Mn2+ is present in a high spin d5 configuration. No magnetic ordering is observed

Octahedral Niobium Chloride Clusters as Building Blocks of Templated Prussian Blue Framework Analogues

The preparation, structure, and magnetic properties of the first three-dimensional framework containing octahedral niobium cyanochloride clusters as building units are reported. Reactions of aqueous solutions of (Me4N)2K2[Nb6Cl12(CN)6] (2) with aqueous solutions of MnCl2 result in the precipitation of the compound (Me4N)2[MnNb6Cl12(CN)6] (3). The structure of 3 was determined from single-crystal X-ray diffraction study (crystal data:  cubic, Fm3̄m (No. 225), a = 15.513(4) Å, V = 3733.2(12) Å3, Z = 4). Its 3D framework is based on edge-bridged [Nb6Cl12]2+ clusters and Mn2+ ions bridged by cyanide ligands to form a cfc lattice [MnNb6Cl12(CN)6]2- in which all tetrahedral sites are occupied by the cations (Me4N)+ which act as charge compensating template. The structure of 3 can be considered as an expansion of the Prussian blue framework in which [Fe(CN)6]4- is replaced by the cluster [Nb6Cl12(CN)6]4-. Magnetic susceptibility measurements indicate that Mn2+ is present in a high spin d5 configuration. No magnetic ordering is observed

Assembly of Hybrid Inorganic−Organic Materials from Octahedral Nb₆ Clusters and Metal Complexes

The octahedral edge-bridged niobium cyano-chloride cluster [Nb6Cl12(CN)6]4- and the [Mn(salen)]+ metal complex have been used as building units to prepare solid-state materials with extended frameworks at room temperature through self-assembly processes. Three materials with different dimensionalities were prepared and characterized:  (Me4N)4[Nb6Cl12(CN)6]·2MeOH (1) (0D), (Me4N)2[Mn(salen)]2[Nb6Cl12(CN)6] (2) (2D), and (Et4N)2[Mn(salen)(MeOH)]2[Nb6Cl12(CN)6]·2MeOH (3) (1D). 1 was used as cluster precursor for the preparation of 2 and 3. The framework dimensionality seems to be affected by the size of the template-counterion used. Single-crystal X-ray analysis revealed that 1 is based on discrete [Nb6Cl12(CN)6]4- separated by (Me4N)+ and MeOH molecules. 2 has a two-dimensional framework, in which each layer is formed by [Nb6Cl12(CN)6]4- clusters connected through four cyanide ligands to four different [Mn(salen)]+. Each manganese complex connects two clusters through Nb−CN−Mn−NC−Nb bridges, leading to the formation of anionic layers interleaved by (Me4N)+. In 3, every cluster unit [Nb6Cl12(CN)6]4- is linked to two [Mn(salen)(MeOH)]+ units through two apical trans cyanide ligands, leading to the formation of trimeric units {Mn−(NC)[Nb6Cl12(CN)4](CN)−Mn}. Every trimeric unit connects to two neighboring units through hydrogen bonding between OMeOH from coordinated methanol ligand and NCN from two neighboring clusters, resulting in the formation of anionic chains along the crystallographic a axis {[Mn(salen)(MeOH)]2[(Nb6Cl12)(CN)6]}2-. The chains are separated by (Et4N)+ and MeOH. Magnetic properties and thermal behavior of these new hybrid inorganic−organic compounds are presented

Assembly of Hybrid Inorganic−Organic Materials from Octahedral Nb₆ Clusters and Metal Complexes

The octahedral edge-bridged niobium cyano-chloride cluster [Nb6Cl12(CN)6]4- and the [Mn(salen)]+ metal complex have been used as building units to prepare solid-state materials with extended frameworks at room temperature through self-assembly processes. Three materials with different dimensionalities were prepared and characterized:  (Me4N)4[Nb6Cl12(CN)6]·2MeOH (1) (0D), (Me4N)2[Mn(salen)]2[Nb6Cl12(CN)6] (2) (2D), and (Et4N)2[Mn(salen)(MeOH)]2[Nb6Cl12(CN)6]·2MeOH (3) (1D). 1 was used as cluster precursor for the preparation of 2 and 3. The framework dimensionality seems to be affected by the size of the template-counterion used. Single-crystal X-ray analysis revealed that 1 is based on discrete [Nb6Cl12(CN)6]4- separated by (Me4N)+ and MeOH molecules. 2 has a two-dimensional framework, in which each layer is formed by [Nb6Cl12(CN)6]4- clusters connected through four cyanide ligands to four different [Mn(salen)]+. Each manganese complex connects two clusters through Nb−CN−Mn−NC−Nb bridges, leading to the formation of anionic layers interleaved by (Me4N)+. In 3, every cluster unit [Nb6Cl12(CN)6]4- is linked to two [Mn(salen)(MeOH)]+ units through two apical trans cyanide ligands, leading to the formation of trimeric units {Mn−(NC)[Nb6Cl12(CN)4](CN)−Mn}. Every trimeric unit connects to two neighboring units through hydrogen bonding between OMeOH from coordinated methanol ligand and NCN from two neighboring clusters, resulting in the formation of anionic chains along the crystallographic a axis {[Mn(salen)(MeOH)]2[(Nb6Cl12)(CN)6]}2-. The chains are separated by (Et4N)+ and MeOH. Magnetic properties and thermal behavior of these new hybrid inorganic−organic compounds are presented

Influence of Different Stiffening Arrangements on the Behaviour of FRP Box Girder Bridge

1. Explore the usefulness of FRP in the box girder bridges to achieve enhanced performance.2. To study the contribution of stiffening of different plates in order to minimize the local plate buckling.3. To access the overall behaviour of this structural system by using a reliable finite element code (ABAQUS)</div

Interface-Mediated YIG/Ce:YIG Bilayers Structure with Enhanced Magneto-optical Properties via Pulsed Laser Deposition

For the realization of integrated nonreciprocal photonic devices for optical communication, on-chip monolithic integration of magneto-optical materials onto silicon remains a challenge. Implemented with pulsed laser deposition (PLD), a MgO interfacial layer is introduced to overcome the material incompatibilities between a silicon substrate and magneto-optical thin films of yttrium iron garnet (YIG). With a thickness of ∼40 nm, the amorphous interfacial layer of MgO can effectively inhibit interdiffusion across YIG/Si and promote the growth of a high-density, high-phase-purity polycrystalline garnet structure in the bilayer of YIG/Ce:YIG. Such modified chemistry and microstructure in YIG/Ce:YIG lead to enhanced magneto-optical properties, including an ∼38% increase in Faraday rotation and an ∼15% increase in saturation magnetization, as well as an ∼20% increase in infrared (IR) transmission. Offering dual functions of diffusion barrier and structure template, the MgO layer demonstrated herein suggests a new remedy solution to heterogeneous interfaces in advanced thin film devices

Second-Harmonic Whispering-Gallery Modes in ZnO Nanotetrapod

We present the observation of second-harmonic (SH) whispering-gallery modes (WGMs) in the hexagonal cross-sections of the tapered ZnO nanotetrapod legs. Because of the continuously changing diameter in the leg, several orders of the WGMs at different SH wavelengths can be on resonance simultaneously at different locations along the leg. The strongest SH WGMs occur when the polarization of the fundamental excitation beam is parallel to the c-axis of the crystal along the leg