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By using 2, 2'-biimidazole (2, 2′-biim) and 2, 2′-bipyridine (2, 2′-bipy) as structure-directing agents (SDAs), two cadmium diphosphonates, [Cd2(H2L)2(H2O)] (1) and [Cd5(HL)2(H2L)2]·4H2O (2) (H4L = 4–F–C6H4CH2N(CH2PO3H2)2), have been hydrothermally synthesized. The introduction of different N-heterocyclic aromatic SDAs results in the diverse structures, thermal stabilities, and luminescent properties. Structural analyses reveal that both 1 and 2 show three-dimensional (3D) supramolecular structures wherein the adjacent layers are further connected by moderately π–π stacking interactions or hydrogen-bond interactions. Among them, the thermal stability of 1 is higher than 2. Surprisingly, 1 displays excellent luminescent performance, whereas 2 shows no luminescent signal. Based on the intense luminescence of 1, it can serve as a high selectively and sensitively luminescent sensor for Hg2+ with a low detection limit of 3.1 × 10–7 M in aqueous solution. Additionally, the probable sensing mechanism for 1 has also been investigated in detail, which can be assigned to the weak interaction between the uncoordinated O sites from the H2L2– ligands and Hg2+. Two cadmium diphosphonates with different structures and luminescent properties have been hydrothermally obtained by using N–heterocyclic aromatic (2, 2′–biim and 2, 2′‒bipy) compounds as SDAs. 1 displays excellent luminescent performance, whereas 2 shows no luminescent signal. Furthermore, 1 can serve as a luminescent sensor for Hg2+ in water [ABSTRACT FROM AUTHOR]

It is promising and challenging to manipulate the electronic structures and functions of materials utilizing both metal‐to‐metal charge transfer (MMCT) and spin‐crossover (SCO) to tune the valence and spin states of metal ions. Herein, a metallocyanate building block is used to link with a FeII‐triazole moiety and generates a mixed‐valence complex {[(Tp4‐Me)FeIII(CN)3]9[FeII4(trz‐ph)6]}⋅[Ph3PMe]2⋅[(Tp4‐Me)FeIII(CN)3] (1; trz‐ph=4‐phenyl‐4H‐1,2,4‐triazole). Moreover, MMCT occurs between FeIII and one of the FeII sites after heat treatment, resulting in the generation of a new phase, {[(Tp4‐Me)FeII(CN)3][(Tp4‐Me)FeIII(CN)3]8 [FeIIIFeII3(trz‐ph)6]}⋅ [Ph3PMe]2⋅[(Tp4‐Me)FeIII(CN)3] (1 a). Structural and magnetic studies reveal that MMCT can tune the two‐step SCO behavior of 1 into one‐step SCO behavior of 1 a. Our work demonstrates that the integration of MMCT and SCO can provide a new alternative for manipulating functional spin‐transition materials with accessible multi‐electronic states. [ABSTRACT FROM AUTHOR]

Understanding the effects of intermolecular interactions on metal‐to‐metal charge transfer (MMCT) is crucial to develop molecular devices by grafting MMCT‐based molecular arrays. Herein, we report a series of solvent‐free {Fe2Co2} compounds sharing the same cationic tetranuclear {[Fe(PzTp)(CN)3]2[Co(dpq)2]2}2+ (PzTp−=tetrakis(pyrazolyl)borate, dpq=dipyrido[3,2‐d:2′,3′‐f]quinoxaline) square units but having anions with different size, including BF4−, PF6−, OTf−, and [Fe(PzTp)(CN)3]−. Intermolecular π⋅⋅⋅π interactions between dpq ligands, which coordinate to cobalt ions in the {[Fe(PzTp)(CN)3]2[Co(dpq)2]2}2+ units, can be modulated by introducing different counterions, regulating the distortion of the CoN6 octahedron and ligand field around the cobalt ions. This change results in different MMCT behavior. Computational analyzes reveal the substantial role of the intermolecular interactions tuned by the presence of different counteranions on the MMCT behavior. [ABSTRACT FROM AUTHOR]

Two tetranuclear cyanide‐bridged FeIII2NiII2 compounds [Ni2(L1)4Fe2(μ‐CN)4(CN)2(L2)2]·2ClO4·CH3OH·4H2O (1) and [Ni2(L1)4Fe2(μ‐CN)4(CN)2(L3)2]·2ClO4 (2) [L1 = 4,4′‐dichloro‐2,2′‐bipyridine; L2 = hydrotris(pyrazolyl)borate; L3 = tetrakis(pyrazolyl)borate] were synthesized. Magnetic measurements indicated that both two compounds showed single‐molecule magnet (SMM) behaviors with the relaxation energy barrier of Δ/kB = 68.9(8) K for 1 and 12.6(1) K for 2. Magneto‐structural analysis indicated that the intermolecular interactions played an important part in the slow magnetic relaxation behaviors. [ABSTRACT FROM AUTHOR]

Utilizing the building block [(Tp R )Fe III (CN) 3 ] − featuring different steric hindrance, a trinuclear [Ni II (4-Clbpy) 2 ][(pzTp)Fe III (CN) 3 ] 2 ·4H 2 O ( 1 ) (pzTp = tetrakis(pyrazolyl)borate; 4‑Clbpy = 4‑chlorine‑2,2′‑dibipyridine) and a tetranuclear {[Ni II (4-Clbpy) 2 ][(Tp*)Fe III (CN) 3 ]} 2 ·4CH 3 OH·2H 2 O ( 2 ) (Tp* = hydrotris(3,5‑dimethylpyrazolyl)borate) were successfully synthesized. Magnetic studies revealed that both compound 1 and 2 exhibited intramolecular ferromagnetic interaction. Dynamic susceptibility study indicated that compound 2 exhibited slow magnetic relaxation. The relaxation energy barrier was Δ/ k B  = 62.31 K with the pre-exponential factor of τ 0  = 2.87 × 10 −10  s. In addition, compound 2 can exhibit hysteresis at 1.8 K. [ABSTRACT FROM AUTHOR]

Electron transfer in solid is crucial to switchable magnetic, electrical, optical and mechanical properties. However, it is a formidable challenge to control electron-transfer behaviors via manipulation of crystalline phases, especially through dynamic crystalline transformation. Herein, three crystalline phases of an {Fe2Co2} compound were obtained via enhancement of intermolecular π···π interactions inducing successive single-crystal-to-single-crystal transformations, from solvated 1·2CH3OH·4H2O, to desolvated 1 and its polymorph 1a accompanying electron transfer. 1·2CH3OH·4H2O showed thermally induced reversible intermetallic electron transfer in mother liquor. No electron-transfer behavior was observed in 1. 1a showed reversible intermetallic electron transfer upon thermal treatment or alternative irradiation with 808- and 532-nm lasers at cryogenic temperatures. The electron-transfer behaviors significantly change the magnetic and optical properties, providing a strategy to realize different electron-transfer behaviors and switchable functions via π···π interactions manipulated dynamic crystalline transformation. [ABSTRACT FROM AUTHOR]

Two types of lanthanide(iii) oxalatophosphonates, namely, [Ln(H2L)(C2O4)]·H2O [Ln = La (1), Ce (2), Pr (3)] and [Ln2(H3L)(C2O4)3(H2O)4]·2H2O [Ln = Eu (4) and Dy (5)] have been hydrothermally obtained by using (4-carboxypiperidyl)-N-methylenephosphonic acid (H3L) as the phosphonate ligand and oxalate as the second ligand. These five compounds have the same precursor, but they exhibit two different 2D layered structures. Compounds 1–3 are isostructural and exhibit a 2D layered structure in which {Ln(1)O9}, {Ln(2)O9} and {CPO3} polyhedra via corner-sharing and edge-sharing are interconnected into a 1D chain. These chains are further cross-linked by oxalate anions into a 2D layered structure, and the uncoordinated carboxylate groups are oriented toward the interlayer space. Compounds 4 and 5 are isostructural and also show a 2D layered structure. Lanthanide ions are interconnected by oxalate anions forming a 2D layered structure, and the carboxyl groups of H3L are grafted on the two sides of the layer. The structure variations are attributed to the effect of lanthanide contraction. In addition, the luminescence properties of compounds 4 and 5, and the magnetic properties of compound 5 have been studied. [ABSTRACT FROM AUTHOR]

Tuning of the spin crossover (SCO) behavior through paramagnetic building blocks with different steric hindrance effects is of great interest in terms of the synergy between SCO and magnetic interactions. Herein, the steric effect of specified FeIII building blocks is modified, from the large Tp* (hydridotris(3,5-dimethylpyrazol-1-yl)borate) analogue to a small Tp (hydrotris(pyrazolyl)borate) derivative; the FeII SCO unit and FeIII paramagnetic ions are incorporated into three well isolated trinuclear complexes featuring thermally induced and light-induced SCO properties. Reanalysis of the structures reveals that π-π stacking interactions play a key role in the thermal hysteresis and anomalous octahedral distortion parameter Σ around the FeII ion. The Tp* ligand showing the largest steric hindrance induces elongated FeII−N bond lengths and bending of the C≡N−FeII angle in 1, as well as having a relatively large electron donor effect, which leads to the lowest thermal transition temperature among the three compounds. [ABSTRACT FROM AUTHOR]

In the search for multifunctional molecular materials, we designed an enantiopure pair of FeII complexes with chiral, chelating (R)/(S)-4,5-pinenepyridyl-2-pyrazine ligands exhibiting three inherent physical properties: chirality, spin crossover, and dielectric switching. The geometrical change resulted in coupling of the spin-crossover transition at 187 K to dielectric switching. Both compounds were found to display light-induced spin crossover that was thermally unstable above ca. 40 K. The coupling of two hysteretic properties, electric and magnetic, renders these compounds as potential switching devices. [ABSTRACT FROM AUTHOR]

A major challenge is the development of multifunctional metal-organic frameworks (MOFs), wherein magnetic and electronic functionality can be controlled simultaneously. Herein, we rationally construct two 3D MOFs by introducing the redox active ligand tetra(4-pyridyl)tetrathiafulvalene (TTF(py)4) and spin-crossover FeII centers. The materials exhibit redox activity, in addition to thermally and photo-induced spin crossover (SCO). A crystal-to-crystal transformation induced by I2 doping has also been observed and the resulting intercalated structure determined. The conductivity could be significantly enhanced (up to 3 orders of magnitude) by modulating the electronic state of the framework via oxidative doping; SCO behavior was also modified and the photo-magnetic behavior was switched off. This work provides a new strategy to tune the spin state and conductivity of framework materials through guest-induced redox-state switching. [ABSTRACT FROM AUTHOR]

A tetranuclear cyanide-bridged Fe III 2 Ni II 2 cluster [Fe III (Tp)(CN) 3 ] 2 Ni II 2 (4, 4′-dibromo-2, 2′-bpy) 4 ·2ClO 4 ( 1 ) (Tp = hydrotris(pyrazolyl)borate) was synthesized. Magnetic measurements indicated that this compound displayed single-molecule magnet behavior with the pre-exponential factor of τ 0 = 1.79(8) × 10 − 10 s and the relaxation energy barrier of Δ/ k B = 65.1(9) K. [ABSTRACT FROM AUTHOR]

Three new alkaline earth metal carboxyphosphonates with a 3D supramolecular structure, namely, Ca[(H3L)(H2O)] (1), Sr[(H3L)(H2O)2] (2) and Ba[(H3L)(H2O)] (3) (H5L = 4-{[bis(phosphonomethyl)amino]methyl}benzoic acid), have been synthesized under hydrothermal conditions. For compound 1, {CaO6} and {CPO3} polyhedra are interconnected into a 1D double-chain via corner-sharing. Adjacent chains are further cross-linked via the organic backbone {–C6H4CH2N(CH2)2–} of the carboxyphosphonate ligands, generating a 2D layer. These neighboring 2D metal phosphonate layers are connected through hydrogen bonding interactions to form a 3D supramolecular structure. In compound 2, two edge-sharing {SrO7} polyhedra form centrosymmetric {Sr2O12} units. Then, these {Sr2O12} units are connected by phosphonate groups to form a 1D chain, which is further cross-linked by N atoms from carboxyphosphonate ligands to form a 2D inorganic layer. These 2D inorganic layers interdigitate through hydrogen bonding interactions to generate a 3D supramolecular structure. In compound 3, the connections of {BaO10} and {CPO3} polyhedra form a 2D layer via corner-sharing and edge-sharing. Then adjacent layers are further assembled into a 3D supramolecular structure through hydrogen bonding interactions. The thermal stabilities and luminescence properties of compounds 1–3 were investigated. Interestingly, compounds 1–3 are selective and reversible for sensing of 1-butanol, 1-propanol and ethanol, respectively. [ABSTRACT FROM AUTHOR]

The present study describes the designed synthesis, X-ray structures, and magnetic properties of two 2D cyano bridged heterobimetallic WV–CoII networks, {[W(CN)8]2[Co(phpy)4]3}·2CH3OH·2H2O (1) and {[W(CN)8]2[Co(4-spy)4]3}·6H2O (2) (phpy = 4-phenylpyridine, 4-spy = 4-styrylpyridine). Both compounds consist of cyano-bridged 12-metal 36-membered ring units, Co6W6(CN)12, joined by organic linkers into a 2D plane. The layer presents a corrugated configuration in compound 1 and a plane configuration in compound 2 due to different π–π stacking interactions. Magnetic measurements reveal that both 1 and 2 have a transition to the spin glass-like phase due to competitive magnetic interactions. [ABSTRACT FROM AUTHOR]

One trinuclear and two tetranuclear cyanide-bridged FeIII–NiII complexes were synthesized via treatment of a tricyanometallate with divalent Ni salts in the presence of 1-butylimidazole, 2,2-bipyrimidyl and 1,10-phenanthroline, respectively. Magnetic property studies demonstrated that the three complexes exhibit single-molecule magnet behavior as a result of strong intracluster ferromagnetic coupling and weak intercluster magnetic interactions. [ABSTRACT FROM AUTHOR]

Hydrothermal reactions of lanthanide(III) chlorides andH2O3PCH2NCH2(CH2CH2OPO2H) (H3L) with oxalate anionleadto six novel lanthanide oxalatophosphonates with a three-dimensional(3D) framework structure, namely, {[Ln(H2L)(C2O4)(H2O)]·nH2O}∞[n= 3(compounds 1–3), 2(compounds 4–6); Ln = Ce (1), Pr (2), Nd (3), Sm (4), Eu (5), and Tb(6)]. Compounds 1–6are isostructural and feature a complex 3D network builtfrom 1D chains of lanthanide oxalate and {Ln(H2L)}2爖ꊞ. These lanthanide oxalatophosphonates possess twotypes of channels with dimensions of 11.6 Å × 4.4 Åand 13.8 Å × 8.9 Å along the a- and b-axis, respectively, and these channels incorporate somecrystalline water molecules therein by hydrogen-bonding interactions.They show an unusual noninterpenetrated (3,5)-connectedtopology. The title compounds were characterized by X-ray single-crystaldiffraction and X-ray powder diffraction (XRD) as well as with infraredspectroscopy and elemental and thermogravimetric analysis. Furthermore,the temperature-dependent powder XRD, the variable temperature IRspectroscopy, and the dehydration/hydration properties of compound 2have also been studied. Luminescent measurements indicatethat the Sm (4) and Eu (5) compounds exhibitstrong luminescence in yellow light and red light regions, respectively. [ABSTRACT FROM AUTHOR]

Abstract: By using the (2-carboxypiperidyl)-N-methylenephosphonic acid as the phosphonate ligand and 1,4-benzenedicarboxylic acid as the second metal linker, a novel cadmium(II) carboxyphosphonate with a 2D layered structure, namely, [Cd2(HL)(bdc)] (1) (H3L═H2O3PCH2―NC5H9―COOH, H2bdc═HOOCC6H4COOH) has been synthesized under hydrothermal conditions. In compound 1, each Cd(II) atoms are octahedrally coordinated [Cd(1)O6, Cd(2)O6]. These cadmium octahedra form a 1D double chain along the b-axis through edge- and corner-sharing, and such chains are further interlinked by the bdc2− anions into a 2D layer in the bc-plane. The luminescent property of compound 1 has also been studied. [Copyright &y& Elsevier]

Eleven new lanthanide oxalatophosphonate hybrids with a 2D layered structures, namely, [Ln(H3L)(C2O4)]·2H2O (Ln = La–Dy, Er and Y, H4L = C6H5CH2N(CH2PO3H2)2), have been synthesized under hydrothermal conditions and structurally characterized by X-ray single-crystal diffraction, X-ray powder diffraction, infrared spectroscopy, elemental analysis and thermogravimetric analysis. Compounds 1–11are isomorphous and they exhibit a 2D framework structure. Two {LnO8} polyhedra and four {CPO3} tetrahedra are interconnected into a unit viacorner-sharing, and the so-built units are bridged by the oxalate anions into a layer. The result of connections in this manner is the formation of a 24-atom window. The thermal stabilities and guest desorption–sorption properties of compounds 1–11have been investigated. The luminescent properties of compounds 5, 6, 8and 9have also been studied. [ABSTRACT FROM AUTHOR]

By introduction of 1,4-benzenedicarboxylic acid as a second organic ligand, two new divalent metal(ii) phosphonates with a 3D framework structure, namely, [Zn(HL1)(bdc)0.5] (1) and [Cd1.5(HL2)(bdc)0.5] (2) (H2L1 = H2O3PCH(NH2)C6H5, H3L2 = H2O3PCH2–NC5H9–COOH, H2bdc = HOOCC6H4COOH), have been synthesized under hydrothermal conditions. The two compounds show three-dimensional (3D) framework structure with infinite two-dimensional (2D) networks pillared by H2bdc. For compound 1, the {ZnO4} polyhedra are interconnected by phosphonate groups into a 2D layer, and the adjacent layers are further cross-linked viathe bdc2−anions to generate a three-dimensional framework structure with two types of channel system along the c-axis. A notable feature of compound 1is the presence of alternate left- and right-handed helical chains in the structure. In compound 2, the inorganic chains, composed of {Cd(1)O7}, {Cd(2)O4} and {CPO3} polyhedra, are linked by HL22−ligands to form a double layer structure in the abplane, and the adjacent layers are further linked by the bdc2−anions to form a 3D framework structure with one-dimensional channel systems along the a-axis. Luminescence properties of compounds 1and 2have also been studied. [ABSTRACT FROM AUTHOR]

Three cyanide-bridged {Fe 2 Co 2 } tetranuclear complexes were synthesized. Magnetic study indicated that 1 exhibited ferromagnetic interaction, while 2 and 3 showed reversible thermally induced intramolecular metal-to-metal charge transfer (MMCT). The role of the σ donor strength of the TpR ligands and the intermolecular interactions on the thermochromic charge transfer properties were discussed based on the magneto-structural relationship analysis. [Display omitted] • Three cyanide-bridged {Fe 2 Co 2 } tetranuclear complexes were synthesized. • 1 exhibits ferromagnetic interaction but 2 and 3 show MMCT behaviors. • The σ donor strength of the TpR ligands can tune the different MMCT properties. Using different cyanometallate building blocks ([(TpR)Fe(CN) 3 ]–) and pyrazino[2, 3-f][1,10]phenanthroline (dpq) ligand, three cyanide–bridged {Fe 2 Co 2 } tetranuclear complexes {[(Tp*)Fe(CN) 3 ] 2 [Co(dpq) 2 ] 2 [ClO 4 ] 2 }·4H 2 O (1), {[(Tp4-Me)Fe(CN) 3 ] 2 [Co(dpq) 2 ] 2 [ClO 4 ] 2 }·4H 2 O (2) and {[(Tp)Fe(CN) 3 ] 2 [Co(dpq) 2 ] 2 [(Tp)Fe(CN) 3 ][ClO 4 ]}·2CH 3 OH·5H 2 O (3) were synthesized. Single crystal X-ray diffraction study showed that all compounds shared the similar square tetranuclear structures. Magnetic study indicated that 1 maintained the high-spin state for the CoII ion in the whole temperature range, and showed the ferromagnetic interaction between low-spin FeIII and high-spin CoII ions. In contrast, 2 and 3 showed thermally and photoinduced intramolecular metal-to-metal charge transfer (MMCT) between the FeII/III and CoII/III redox pairs. The comparison study suggested that the electronic and steric effects of the substituents in cyanometallate building blocks as well as the intermolecular interactions can affect the redox potential of metal ions, thereby resulting in different MMCT properties. [ABSTRACT FROM AUTHOR]

Abstract Three one-dimensional (1D) cyanide-bridged heterobimetallic chains {[FeIII(Tp)(CN) 3 ] 2 CoII(mep) 2 }·2CH 3 OH (1 ; Tp = hydrotris(pyrazolyl)borate, mep = 4‑[(1 E)‑2‑(4‑Methylphenyl)ethenyl]pyridine), {[FeIII(Tp)(CN) 3 ] 2 CoII(eep) 2 }·2CH 3 OH (2 ; eep = 4‑[(1 E)‑2‑(4‑Ethylphenyl)ethenyl]pyridine) and {[FeIII(Tp)(CN) 3 ] 4 CoII 2 (nep) 4 }·3H 2 O·CH 3 OH (3 ; nep = 4‑[(1 E)‑2‑(2‑Naphthalenyl)ethenyl]pyridine) have been synthesized via self-assembly of the same [FeIII(Tp)(CN) 3 ]− unit and CoII ion in the presence of different N -substituted pyridine ligands. Magnetic measurements reveal that complex 1 exhibits ferromagnetic interactions and a long-range magnetic ordering below 3.5 K. Complex 2 shows antiferromagnetic long-range ordering below 3.3 K, while complex 3 shows a typical ferrimagnetic coupling at low temperatures. These results highlight the significant influence of the coligands on their magnetic properties. Graphical abstract Three one-dimensional cyanide-bridged {FeIII 2 CoII} n chains with different N -substituted pyridine ligands were synthesized and characterized. Magnetic measurements reveal that complex 1 exhibits ferromagnetic interactions and a long-range magnetic ordering. Complex 2 shows antiferromagnetic long-range ordering, while complex 3 shows a typical ferrimagnetic coupling. The alteration of the coligands greatly influences the magnetic coupling interactions and finally results in different magnetic properties. Unlabelled Image Highlights • Three one-dimensional cyanide-bridged {FeIII 2 CoII} n chains were synthesized. • Magnetic measurements indicated that three compounds displayed completely different behavior. • The alteration of the coligands results in different magnetic properties. [ABSTRACT FROM AUTHOR]

Three novel cyano-bridged one-dimensional chains {[(pzTp)Fe(CN) 3 ] 2 M(BYI) 2 (CH 3 OH) 2 ·2CH 3 OH} n (M = Mn ( 1 ), Co ( 2 ) and Ni ( 3 ), BYI = 1, 1′-(1, 4-Butanediyl)bis(imidazole)) composed of cyano-bridged trinuclear Fe III 2 M II units were successfully synthesized based on [(pzTp)Fe(CN) 3 ] − (pzTp = tetrakis(pyrazolyl)borate) unit and bidentate bridging ligand. Structural characterization showed that the three compounds were isostructural. The magnetic interactions could be adjusted by replacing the metal ions with different magnetic anisotropy. Magnetic studies revealed that compound 1 showed antiferromagnetic interaction, while compounds 2 and 3 exhibited ferromagnetic interaction. Interestingly, compound 3 showed the spin glass behavior with the typical slow magnetic relaxation due to the large anisotropy for Ni II ions and the non-negligible interchain interaction. [ABSTRACT FROM AUTHOR]

A cyano-bridged ferromagnetic {Fe III 2 Fe II } alternating chain {[Fe III (pzTp)(CN) 3 ] 2 [Fe II (imidazole)(H 2 O)]}·3H 2 O ( 1 ) (pzTp = tetrakis(pyrazolyl)borate) was synthesized via rational design. Crystal structure analysis studies demonstrated that complex 1 had a one-dimensional double zigzagging chain-like structure. Magnetic measurements showed that ferromagnetic interactions dominate in 1 and the AC magnetic susceptibility revealed two limit regimes in accordance with the single chain magnet and spin-glass behavior. [ABSTRACT FROM AUTHOR]

The preparation, single-crystal X-ray crystallography and magnetic properties are reported for two single-zigzag chain complexes {[W(CN) 8 ][Ni(imi) 4 ]}·Bu 4 N·CH 3 OH·2H 2 O ( 1 ) and {[Mo(CN) 8 ][Ni(imi) 4 ]}·Bu 4 N·2H 2 O ( 2 ) (imi = imidazole, Bu = normal-butyl). The structure studies reveal that both complexes feature one-dimension anion chains linked by [W(CN) 8 ] 3 − units in 1 or [Mo(CN) 8 ] 3 − units in 2 . Magnetic studies show that strong ferromagnetic exchange is operative within the W V (μ-CN)Ni II units for ( 1 ) and Mo V (μ-CN)Ni II units for ( 2 ). [ABSTRACT FROM AUTHOR]

Two new cobalt phosphonates, [enH2]0.5[Co(HL)(H2O)]·H2O (1) and [Co2(HL)(H2L)2]·2NH(CH3)2 ·3H2O (2) (H3L=2-hydroxyphosphonoacetic acid; en=ethylenediamine), have been synthesized under hydrothermal conditions and structurally characterized by X-ray single-crystal diffraction, X-ray powder diffraction, infrared spectroscopy, elemental analysis and thermogravimetric analysis. For compound 1, Co(II) atoms are octahedrally coordinated. The CoO6 octahedra and CPO3 tetrahedra are linked by HL2− into a 2D layered structure in the bc-plane. The ethylenediamine molecules and solvate water molecules are located between two adjacent layers. The structure of compound 2 composed of Co1O6 and Co2O6 octahedra via bridging phosphonate ligands leads to a 2D layered structure with one-dimensional channel system along c-axis direction. The dimethylamine molecules and solvate water molecules are located between two adjacent layers. The surface photovoltage properties of compounds 1 and 2 have also been studied. [ABSTRACT FROM AUTHOR]

Abstract: By using the N-morpholinomethylphosphonic acid as the phosphonate ligand and 1,4-benzenedicarboxylic acid as the second metal linker, a novel cadmium(II) phosphonate with a 3D framework structure, namely, [Cd2(HL)(bdc)(Hbdc)] (1) (H2L=O(CH2CH2)2NCH2PO3H2, H2bdc=HOOCC6H4COOH) has been synthesized under hydrothermal conditions. In compound 1, the {CdO6} and {CdO7} polyhedra are interconnected by phosphonate groups into a 1D chain, each chain is connected by the bdc2− anions into a 2D layer, and the adjacent layers are further linked via the bdc2− anions to form a 3D framework structure with a 1D channel system along the a-axis. Luminescent property of compound 1 has also been studied. [Copyright &y& Elsevier]

Two hexanuclear complexes of formula [Fe III (Tp*)(CN) 3 ] 4 [Fe II (tptz)] 2 ( 1 ), [Fe III (Tp*)(CN) 3 ] 4 [Co II (tptz)] 2 ( 2 ) [Tp* = hydridotris(3,5-dimethylpyrazolyl)borate, tptz = (2,4,6-tris-(2-pyridyl)1,3,5-triazine] have been synthesized via directional assembly of metallocyanate precursor and metal cationic ions. The magnetic properties characterization indicate that ferromagnetic interactions dominate in the two complexes, resulting in a spin ground state of S = 5 and S = 6, respectively. [ABSTRACT FROM AUTHOR]

A cyano-bridged Fe 2 Co 4,2-ribbon chain, {[Fe(bipy)(CN) 4 ] 2 [Co(phpy) 2 ]} (1 , bipy = 2,2-bipyridine; phpy = 4-phenylpyridine) was obtained by the dehydration of {[Fe(bipy)(CN) 4 ] 2 [Co(phpy) 2 ]}·2H 2 O (1·2H 2 O). The dehydrated 1 exhibits the water-actuated single-chain magnetic (SCM) behaviour through the dehydration-switchable electron-transfer-coupled spin transition (ETCST). • A water-induced charge transfer occurs through the dehydration process from 1 · 2H 2 O to 1. • The dehydrated 1 with ferromagnetic coupling exhibits single-chain magnetic behavior. • It provides new access to control the switchable molecular nanomagnets by external stimuli. A cyanide-bridged Fe 2 Co 4,2-ribbon single-chain magnet, {[Fe(bipy)(CN) 4 ] 2 [Co(phpy) 2 ]} (1 , bipy = 2,2-bipyridine; phpy = 4-phenylpyridine) was obtained by the dehydration of {[Fe(bipy)(CN) 4 ] 2 [Co(phpy) 2 ]}·2H 2 O (1 · 2H 2 O). The electron-transfer-coupled spin transition (ETCST) was achieved during the dehydration process from 1 · 2H 2 O to 1 , with the electronic configurations transforming from {FeII LS (µ -CN)CoIII LS (µ -NC)FeIII LS } to {FeIII LS (µ -CN)CoII HS (µ -NC)FeIII LS } (LS = low spin, HS = high spin). The magnetic characterization indicates that the dehydrated 1 exhibits the dehydration-actuated single-chain magnetic (SCM) behaviour. [ABSTRACT FROM AUTHOR]