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Tuneable pressure effects associated with changing interlayer distances in two-dimensional graphene oxide (GO)/reduced GO (rGO) layers are demonstrated through monitoring the changes in the spin-crossover (SCO) temperature (T1/2) of [Fe(Htrz)2(trz)](BF4) nanoparticles (NPs) incorporated in the interlayer spaces of the GO/rGO layers. The interlayer separation along the GO to GO/rGO-NP composites to rGO series decreases smoothly from 9.00 Å (for GO) to 3.50 Å (for rGO) as the temperature employed for the thermal reduction treatments of the GO-NP composites is increased. At the same time, T1/2 increases from 351 K to 362 K along the series. This T1/2 increment of 11 K corresponds to that observed for pristine [Fe(Htrz)2(trz)](BF4) NPs under a hydrostatic pressure of 38 MPa. The influence of the stacked layer structures on the pseudo-pressure effects has been further probed by investigating the differences in T1/2 for [Fe(Htrz)2(trz)](BF4) that is present in the composite as larger bulk particles rather than as NPs.


(a) Schematic illustration of the tunable pressure effects caused by the transformation of GO to rGO. (b) between the interlayer distances and the estimated pseudo-pressure values

Sci. Rep., 2017 , 7, 12159. .

Zero in-plane thermal expansion (TE) in a two-dimensional (2D) coordination polymer is demonstrated. The combination of components that expand and those that shrink into zigzag layers results in no net area change in the 2D materials with temperature. Single crystals of [Mn(salen)]2[Mn(N)(CN)4(guest)] (salen = N,N′-ethylenebis (salicylideneaminato), guest = MeOH and MeCN) were prepared, and variable-temperature single-crystal X-ray structural analyses demonstrated that these compounds exhibited both anisotropic positive and negative thermal expansion depending on the guest species. The TE behavior results from distortions of the octahedral coordination geometry of [Mn(salen)]+ units in the zigzag layers. When both guests MeOH and MeCN were incorporated into one material, [Mn(salen)]2[Mn(N)(CN)4(MeOH)0.25(MeCN)0.75], zero in-plane TE resulted in a range of temperature between 380 and 440 K.


Inorg. Chem., 2017 , 56, 6225-6233. .

Two ferromagnetic coupled multinuclear Ni(II) clusters, [Ni4L143-OMe)4(CH3OH)4] (1) and [Ni7(HL2)63-OMe)6]Cl2 (2) were synthesized, and their structures and magnetic behaviors were investigated in detail. 1 has a [Ni4O4] cubane structure while 2 has a wheel-like [Ni@Ni6] arrangement. The temperature-dependent magnetic susceptibilities for 1 and 2 are in accord with the presence of dominating intra-cluster ferromagnetic interactions between Ni(II) ions. The best fits for their behaviors gave the following parameters: J1 = 11.06 cm−1, J2 = 1.43 cm−1, g = 2.29 for 1, and J1 = 6.87 cm−1, J2 = −3.41 cm−1, g = 2.24 for 2.


Crystal structures and magnetic behaviors of (a) cubane-type and (b) wheel-type multinuclear nickel(II) clusters.

Dalton trans., 2017 , 46, 8555-8561. .

Supramolecular lipophilic complex cations displaying cobalt(II) SCO properties combined with lipid counter ions have been constructed. The influence of odd (n = 15, 17 and 19)/even (n = 16, 18 and 20) long alkyl chains on the formation of wire and rolled sheet arrangements respectively was documented. However, in the case of the alkyl chains with lengths corresponding to n = 0-14, no supramolecular architectures were observed. Overall, this study reveals the supramolecular structural diversity that ionic lipid self-assembled molecules of the present type can display depending on the length of the alkyl chain in the cobalt() complex investigated.


TEM images of (a) [Co(C15-terpy)2](C12-Glu)2 and (b) [Co(C16-terpy)2](C12-Glu)2

Chem. Commun., 2017 , 53, 4685-4687. .

Slight changes in the coordination structure of the manganese(V)-nitrido anionic complex, [MnV(N)(CN)4]2−, induced by using a “lipid package” approach markedly made an impact on the corresponding redox potentials. The single crystals of four lipid assemblies, [dabco-(CH2)n−1-CH3]2[Mn(N)(CN)4(H2O)]·xH2O (n = 15, 16, 17 and 18; dabco = 1,4-diazabicyclo[2,2,2]octane), were synthesized and solid-state cyclic voltammetric studies demonstrated that the [MnV(N)(CN)4]2− anions with smaller “cross” NC–Mn–CN bond angles exhibit higher redox potentials. The observed trend reflects the energy change associated with the structural transformation from [MnV(N)(CN)4]2− to [MnVI(N)(CN)4]2− and is supported by the results of DFT calculations. The NC–Mn–CN bond angles in the flexible [Mn(N)(CN)4]2− structure exhibit excellent correlation with the redox potentials of the complexes in the solid state.


(a) Crystal structures of the metal complex lipids and (b) Correlation between coordination bond angles and redox potentials.

Dalton Trans., 2017, 46, 3749-3754.

Cobalt(II) complexes of type [Co(R-C6-terpy)2](BF4)2 (R = A (1) and T (2)) and a co-crystal of type [Co(A-C6-terpy)1.5(T-C6-terpy)0.5](BF4)2 (3) were prepared. We have investigated assembly arrangement of the compounds. A 3-D network structure is present in 1 that incorporates 1-D chains, while 2 adopts a 2-D stacked structure constructed from ladder-type assemblies. For 3, “dimer-rings” consisting of [Co(A-C6-terpy)2]2 and [Co(A-C6-terpy)(T-C6-terpy)]2 units are generated via base-pairing between A and T. It is noteworthy that 3 displays the first crystal structure of a heteroleptic cobalt(II) complex of [Co(A-C6-terpy)(T-C6-terpy)](BF4)2.


(a) Single crystal structures and (b) temperature dependence of magnetic susceptibilities.

Eur. J. Inorg. Chem., 2016, 23, 7232-7237.

Insertion of 3-hydroxypropanesulfonicacid (HPS) in the graphene oxide (GO) interlayer results in high proton conductivity (10-2-10-1 Scm-1), owing to an improvement in oxygen content, interlayer distance and water absorbing capacity. This result indicates that hydroxyalkylsulfonicacids can be perfect guest molecules for improving the proton conductivity of carbon materials.


(a) Single crystal structures and (b) temperature dependence of magnetic susceptibilities.

Chem. Asian J., 2017, 12, 194-197.

Chiral and racemic iron(II) complexes, [Fe((R)-L)2(NCS)2] (1), [Fe((S)-L)2(NCS)2] (2) and [Fe((R,S)-L)2(NCS)2] (3) (L = α-methyl-N-(2-pyridinylmethylene)-cyclohexanemethanamine) were synthesized. All complexes exhibited spin-crossover (SCO) behaviors. Complexes 1 and 2 showed similar gradual SCO behavior and complex 3 more abrupt SCO behavior. From Mössbauer spectrometry, increasing chirality causes an increasing contribution of LS state.


(a) Single crystal structures and (b) temperature dependence of magnetic susceptibilities.

Eur. J. Inorg. Chem., 2017, 1049-1053.


Dalton Trans. 2016, 45, 16784-16788.


Chem. Asian J. 2016, 11, 2322-2327.
    

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