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Abstract Intermetallic compounds (IMCs) exhibits unique structural features accompanied by appropriate changes in the electronic structures. These electronically and geometrically tuned structures found to be the excellent catalysts for selected chemical reactions. There is not enough literature comprising detailed synthesis, properties and catalytic activity of IMCs. In this review, a complete overview of the IMCs in the field of heterogeneous catalysis has been discussed in detail. The review starts with understanding IMCs and how are they different from alloys, solid solutions and bimetallic. The physicochemical properties such as electronic effect, geometrical effect, steric effect and ordering of the IMCs are explained with appropriate examples. The comprehensive discussion on the synthesis and characterization of IMCs by various methods are also included in the review. The review cover the classification of IMCs into mainly 3 groups based on the active metal a) Platinum b) Palladium c) Nickel and the compounds based on each of these family is discussed along with the structure-activity correlation in different organic reactions. Several miscellaneous examples including other active metals Rh, Ru, Al, and Co are also included in the review followed by the future perspective. Overall, one can fine-tune and design the essential electronic -geometrical properties in the IMCs by combining appropriate metals, leading to the new surface properties suitable for the important organic reactions. Graphical abstract The catalytic activity and selectivity of metals towards selected organic reactions can be improved by isolated and ordered atomic arrangement in their intermetallic compound. Image 1 [ABSTRACT FROM AUTHOR]

Highlights: [•] The single crystal growth of Yb2CuGe6 and Yb3Cu4Ge4 using metal flux technique. [•] The crystal structures are supported by electronic structure calculations. [•] Yb atoms exist as intermediate valent in Yb2CuGe6 and trivalent in Yb3Cu4Ge4. [Copyright &y& Elsevier]

Abstract: Single-phase samples of Yb4LiGe4 and Yb5Ge4 were synthesized using high frequency (HF) heat treatment. Yb4LiGe4 crystallizes in orthorhombic space group Pnma with the Gd5Si4 type of crystal structure and lattice parameters a =7.0828(3)Å, b =14.6415(7)Å, and c =7.6279(4)Å. One Yb position in Yb5Ge4 is substituted by the lithium atom and causes a distortion of the germanium tetragons in Yb4LiGe4. Investigation of the electronic state of Yb via magnetic susceptibility and X-ray absorption near-edge spectroscopy (XANES) revealed a presence of two electronic states of ytterbium, 4f 13 and 4f 14 (mixed valence), in Yb5Ge4 and Yb4LiGe4. Studies of the temperature dependence of the electrical resistivity, magnetization, 7Li spin-lattice relaxation rate and the specific heat indicate that strong electronic correlations are present in Yb4LiGe4, and below approximately 50K there is a competition between ferromagnetic and antiferromagnetic correlations. Magnetic ordering in Yb4LiGe4, if present, occurs below the reported antiferromagnetic transition temperature of 1.7K for Yb5Ge4. [Copyright &y& Elsevier]

• High energy triplet emission from simple phthalimide derivative in solution-processable thin film. • Ambient tunable room temperature phosphorescence in amorphous polymeric matrix and in crystalline state. • Easy synthesis and high reaction yield. Harvesting triplet excitons via room temperature phosphorescence (RTP) from purely organic chromophores has been a formidable challenge, which has a potential applications in displays, lighting, and bio-imaging. Herein, a simple phthalimide phosphor derivative is reported, which exhibits visible cyan emissive phosphorescence in solution-processable thin films and orange-red emitting phosphorescence in the crystalline state. Presence of carbonyl group and the bromine atom in the molecular design effectively increases the inter-system crossing (ISC) and spin-orbit coupling efficiency (SOC) between singlet and triplet states, which play a crucial role in achieving efficient phosphorescence under ambient conditions. [Display omitted] [ABSTRACT FROM AUTHOR]

• Nano sized Bi 1−x Tb x FeO 3 synthesized using sol gel with x ranging from 0 to 0.12. • An anomalous variation in magnetization with increase in Tb doping content is seen. • The highest magnetization is observed at 3% Tb doping concentration. • Results from Mossbauer spectroscopy corroborate the bulk magnetic measurements. Bi (1−x) Tb x FeO 3 (x = 0, 0.03, 0.04, 0.06, 0.09, 0.12) nanoparticles are prepared by sol-gel method. X-ray diffraction analysis shows the formation of perovskite structure in the synthesized samples and crystallite sizes in the range of 15 nm. The perovskite structure together with the presence of a strong absorption peak observed at 545 cm−1 in the Fourier Transform Infrared Spectroscopy measurements, characteristic of FeO 6 octahedral, confirms the formation of single phase BiFeO 3 structure. The cycloidal spin nature of BiFeO 3 is said to be suppressed in particles that are less than 62 nm across enhancing the ferromagnetic signature. The magnetic behaviour of the Bi (1−x) Tb x FeO 3 nanoparticles is found to change anomalously with change in Tb doping. Vibrating-sample magnetometer studies reveal a maximum in the magnetic moment for a Tb doping concentration of x = 0.03 with clear ferromagnetic order at room temperature. With increase in x beyond 0.03, magnetization decreases, while a further increase beyond x = 0.04 once again increases the magnetization. Room temperature Mossbauer spectroscopy reveals the presence of a paramagnetic doublet and a sextet, the variation of whose relative ratios is in corroboration with the magnetization studies. [ABSTRACT FROM AUTHOR]

Three novel trinuclear Ni(II) complexes, [Ni 3 (L 1 ) 2 (py) 4 ] ( 1 ), [Ni 3 (L 2 ) 2 (H 2 O) 2 (DMA) 2 ] ( 2 ) and [Ni 3 (L 3 ) 2 (py) 4 ] ( 3 ), with trianionic pentadentate ligands derived from salicylhydrazide with N-acyl substituents [H 3 L 1 = N 2 -crotonoylsalicylhydrazide, H 3 L 2 = N 2 -(3,3-dimethylacryloyl)salicylhydrazide, H 3 L 3 = N 2 -cinnamoylsalicylhydrazide] were synthesized and characterized by elemental analysis, spectroscopic techniques, like UV–Vis, FT-IR and NMR, molar conductivity and magnetic susceptibility measurements, and single crystal X-ray diffraction. The solid state structures of the complexes reveal the binding modes of the different ligands via ONO donor atoms. Complex 1 crystallises in the triclinic system while complexes 2 and 3 crystallise in the monoclinic system with space groups P 1 ¯ ( 1 ) and P 2 1 / c ( 2 and 3 ). Computational studies were performed using Density Functional Theory (DFT) to obtain physical properties of all three complexes. The ligands and their metal complexes were screened for antibacterial activity to assess their inhibition potential against two Gram positive bacteria; Staphylococcus aureus and Bacillus subtilis and two Gram negative bacteria; Escherichia coli and Pseudomonas aeruginosa by the well diffusion method using gentamicin as a positive control. Antibacterial screening data reveals that the trinuclear Ni(II) complexes have significantly enhanced inhibitory activities compared to the ligands. [ABSTRACT FROM AUTHOR]

The germanides Sc T Ge ( T = Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, Au) were obtained in X-ray pure form by arc-melting of the elements. The structures of the members with T = Co, Ni, Cu, Rh, Pd, Ag, Ir, and Pt were refined on the basis of single crystal X-ray diffractometer data. The germanides with T = Cu, Ru, Pd, Ag crystallize with the hexagonal ZrNiAl type structure, space group P 6 ¯ 2 m and those with T = Co, Ni, Rh, Ir, Pt adopt the orthorhombic TiNiSi type. ScAuGe is isotypic with NdPtSb. All germanides exhibit single scandium sites. A simple systematization of the structure type according to the valence electron concentration is not possible. The 45 Sc solid state NMR parameters (Knight shifts and nuclear electric quadrupole coupling constants) of those members crystallizing in the TiNiSi structure show systematic trends as a function of valence electron concentration number. Furthermore, within each T -group the Knight shift decreases with increasing atomic number; this correlation also includes previously published results on the isotypic silicide family. The 45 Sc quadrupolar interaction tensor components are generally well-reproduced by quantum mechanical electric field gradient calculations using the WIEN2k code. [ABSTRACT FROM AUTHOR]

The results of magnetic studies and Mössbauer spectroscopic investigations are reported for the stannides TbRhSn and DyRhSn crystallizing in the hexagonal ZrNiAl-type structure. The polycrystalline samples of these ternary intermetallics were synthesized by arc melting from metallic precursors. Detailed 119Sn Mössbauer spectroscopic studies are used to investigate the hyperfine interactions and their temperature evolutions at places occupied by the diamagnetic tin nuclei. Magnetic properties of DyRhSn and TbRhSn were studied by AC/DC magnetometry in a wide temperature range. The results show that both compounds are magnetically ordered at low temperatures. DyRhSn is a non-collinear antiferromagnet with the Néel temperature T N = 7.5 K, whereas TbRhSn undergoes a transition from a paramagnetic to an antiferromagnetic state at T N = 20.2 K. An additional transition at T SR = 10.3 K is detected for TbRhSn which corresponds to some changes in the magnetic moments ordering. The role of the magnetostriction effect in the evolution of the hyperfine parameters and its influence on the observed TbRhSn Mössbauer spectra is discussed. Triangular-like antiferromagnetic arrangements with rare-earth magnetic moments lying in the hexagonal plane are proposed for both compounds at very low temperatures. [ABSTRACT FROM AUTHOR]

Highlights: [•] The structure and properties of Ce x Mg y Ga2−x−y, Eu(Li/Mg) x Ga2−x and Eu(Li/Mg) x Ga4−x. [•] EuMg x Ga2−x (0⩽ x ⩽0.73) and Ce0.82Mg0.50Ga1.68 are new compounds. [•] The substitution of Li/Mg affects the magnetic properties of the compounds. [ABSTRACT FROM AUTHOR]

We synthesize single-crystals of ScPdBi, a Half-Heusler compound by self-flux growth technique and report its physical properties such as magneto-transport and specific heat down to 2 K. Resistivity measurements were performed on these single-crystals at ambient and high-pressure conditions. Temperature-dependent resistivity measurements reveal that ScPdBi shows the metallic character at ambient pressure and without applied magnetic field. The metallic character of ScPdBi was un-altered even in extreme conditions such as high pressure (up to 19 GPa) and magnetic field (up to 9 T). We observe an upturn in the resistivity which persists even at high pressure. We rule-out the presence of the Kondo effect by performing the specific heat measurements down to 2 K which resulted in a low Sommerfeld coefficient (γ ≈ 2.6 ± 0.9 mJ mol−1 K−2). This anomaly in resistivity below 30 K could be attributed to an electron-hole scattering process or a carrier imbalance effect. Resistivity measurements at extreme conditions on ScPdBi single crystals reveal the metallic nature and was un-altered even at extreme conditions. Image 1 • Single crystals of ScPdBi grown by flux growth technique. • Electrical transport measurements show that ScPdBi crystals are metallic in nature. • Ruled out the possible Kondo nature with help of specific heat measurements. • Low temperature anomaly is due to percolative transport/electronic disorders. [ABSTRACT FROM AUTHOR]

A novel vanadyl complex, [V(IV)O(2,6-pyridine diacetatato) (H 2 O) 2 (PDOV) has been synthesized and tested in vivo in a population of STZ-induced diabetic rats. Effective hyperglycemic attenuation was achieved at a relatively low intraperitoneal and oral dosage of the complex and was complemented by a prolonged residual activity over a period of 90 days. • A novel vanadyl complex, PDOV, has been synthesized and characterized. • pH-controlled release of PDOV from polymer coated mesoporous silica, showed a higher rate of release at pH 7.4 than pH 2. • Intraperitoneal administration of PDOV, at 75 mg/kgbw, decreased blood glucose levels in diabetic rats. • Oral administration of PDOV, at 100 mg/kgbw, decreased blood glucose levels in diabetic rats. • A dosage regime of 1 in every 5 days, was able to maintain lower glucose levels for a period of 90 days. The synthesis and characterization of a novel vanadyl complex, [V(IV)O(2,6-pyridine diacetatato)(H 2 O) 2 (PDOV) is reported. The pH-controlled release of the complex from polymer coated mesoporous silica was demonstrated for possible oral administration; results showed that release at pH 2 was significantly lower than that at pH 7.4. The said complex was subsequently screened for possible anti-diabetic activity, via an in vivo dose-response study (intraperitoneal and oral supplementation of PDOV) for 90 days in streptozotocin (STZ) induced diabetic rats. The results revealed that over a 90 day period, intraperitoneal administration of PDOV (at a dose of 75 mg/kgbw) and oral administration of the PDOV (at a dose of 100 mg/kgbw) were effective in suppressing the hyperglycemic state in the diabetic subjects. Exposure to PDOV was found to have little impact on the insulin levels of diabetics; however improved urea, creatinine, AST and ALT levels were noted. [ABSTRACT FROM AUTHOR]

Brownmillerite KBiFe 2 O 5 (KBFO) absorbs large part of the solar spectrum due to its smaller bandgap. This optical response has immense potential in photocatalytic applications. In this work, KBFO was successfully synthesized using citrate combustion method. X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS) as well as Mössbauer spectroscopic studies, identify the valence state of Iron (Fe) as Fe3+. The strong magneto-dielectric coupling in KBFO was demonstrated by integrating both magnetization (M) and dielectric constant (ε) characteristics as a function of temperature. Magnetic and dielectric transitions were observed in close proximity in temperature range ∼780 K–760 K respectively. To the best of our knowledge, the photoelectrochemical properties of as developed KBFO were analyzed for the first time revealing a significant photoresponse with an average photocurrent density of 0.1 μA cm−2. The photocatalytic properties of KBFO were investigated by degrading organic effluent methylene blue (MB) under direct sunlight followed by a comparison with the photodegradation performance of perovskite BiFeO 3 (BFO). KBFO showed enhanced photocatalytic performance as compared to BFO due to its enhanced structural and optical properties. Image 1 • Multifunctional brownmillerite KBiFe 2 O 5 developed using citrate combustion method. • Strong magneto-dielectric coupling in KBiFe 2 O 5. • Photoelectrochemical properties of KBiFe 2 O 5 analyzed for first time and average current density found to be ∼0.1 μA/cm2 • Enhanced photodegradation efficiency of KBiFe 2 O 5 (E g = 1.67eV), over regular perovskite BiFeO 3 (Eg = 2.1 eV). [ABSTRACT FROM AUTHOR]