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The burgeoning interest in the field of molecular magnetism is to perceive the high magnetic anisotropy in different geometries of metal complexes and hence to draw a magneto-structural correlation. Despite a handful of examples to exemplify the magnetic anisotropy in various coordination geometries of mononuclear complexes, the magnetic anisotropies for two different coordination geometries are underexplored. Employing an appropriate synthetic strategy utilizing the ligand LH2 [2,2′-{(1E,1′E)-pyridine2,6-diyl-bis(methaneylylidine)}-bis(azaneylylidine)diphenol] and cobalt halide salts in a 1 : 2 stoichiometric ratio in the presence of triethylamine allowed us to report a new family of dinuclear cobalt complexes [Co II2 X2(L)(P)(Q)]·S with varying terminal halides [X = Cl, P = CH3CN, Q = H2O, S = H2O (1), X = Br, P = CH3CN, Q = H2O, S = H2O (2), X = I, P = CH3CN, and Q = CH3CN (3)]. All these complexes are characterized through single crystal X-ray crystallography, which reveals their crystallization in the monoclinic system P21/n space group with nearly identical structural features. These complexes share vital components, including Co(II) centers, a fully deprotonated ligand [L]2−, halide ions, and solvent molecules. The [L]2− ligand contains two Co(II) centers, where phenolate oxygen atoms bridge the Co(II) centers, forming a Co2O2 four-membered ring. Co1 demonstrates a distorted pentagonal-bipyramidal geometry with axial positions for solvent molecules, while Co2 displays a distorted tetrahedral geometry involving phenolate oxygen atoms and halide ions. Temperature-dependent dc magnetic susceptibility measurements were conducted on 1–3 within a range of 2 to 300 K at 1 kOe. The χmT vs. T plots exhibit similar trends, with χmT values at 300 K higher than the spin-only value, signifying a significant orbital contribution. As the temperature decreases, χmT decreases smoothly in all the complexes; however, no clear saturation at low temperatures is observed. Field-dependent magnetization measurements indicate a rapid increase below 20 kOe, with no hysteresis and a low magnetic blocking temperature. DFT and CASSCF/NEVPT2 theoretical calculations were performed to perceive the magnetic interaction and single-ion anisotropies of Co(II) ions in various ligand-field environments. [ABSTRACT FROM AUTHOR]

To study the effect of diamagnetic ions on magnetic interactions, utilizing a compartmental ligand (Z)-2-(hydroxymethyl)-4-methyl-6-((quinolin-8-ylimino)methyl)phenol (LH2), two different series of ZnII–LnIII complexes, namely the trinuclear series of [DyZn2(L)2(μ2-OAc)2(CH3OH)2]·NO3·MeOH (1), [TbZn2(L)2(μ2-OAc)2(CH3OH)2]·NO3·5MeOH·H2O (2), and [GdZn2(L)2(μ2-OAc)2(CH3OH)2]·NO3·MeOH·CHCl3 (3) and the tetranuclear series of [Dy2Zn2(LH)4(NO3)4(μ2OAc)]·NO3·MeOH·H2O (4), [Tb2Zn2(LH)4(NO3)4(μ2-OAc)]·NO3·MeOH·2H2O (5), and [Gd2Zn2(LH)4(NO3)4(μ2-OAc)]·NO3·MeOH·2H2O (6), were synthesized. Trinuclear ZnII–LnIII complexes 1–3 consist of one LnIII ion sandwiched between two peripheral ZnII ions forming a bent type ZnII–DyIII–ZnII array with an angle of 110.64°. Tetranuclear ZnII–LnIII complexes 4–6 are basically a combination of two dinuclear moieties of [LnZn(LH)2(NO3)2]+ connected by one bidentate bridging acetate ion in μ2-OAc coordination mode. The detailed magnetic analysis reveals that complexes 1 and 4 are single molecule magnets having energy barriers of 34.98 K and 46.71 K with relaxation times (τ0) of 5.05 × 10−4 s and 5.24 × 10−4 s, respectively. Ab initio calculations were employed to analyze the magnetic anisotropy and magnetic exchange interaction between the ZnII and LnIII centers with the aim of gaining better insights into the magnetic dynamics of complexes 1–6. [ABSTRACT FROM AUTHOR]

The uniqueness of human fingerprint plays the most prominent role in forensic investigation as a physical evidence Which is useful for criminal identification. With its unique features no two fingerprints have ever been found to be identical. In legal cases the identification of such print established the relationship between crime scene and the culprit. Generally, there are three types of fingerprint is to be found visible print, plastic print and latent print ( invisible print) which has been taken in account for identification. There is no such crucial method is used for decipher the visible print and plastic print because they are easily visible to naked eye but in case of latent print the process for enhancement is necessary for the latent fingerprint to be observed by naked eye. The most encountered fingerprint is the latent fingerprint which is unconsciously left by perpetrators at any surface. For visualizing such prints Various method have been reported for the development of latent fingerprint on different surfaces. This present study introducing a new visualizing agent for the development of latent fingerprint by using Carbon Powder on various non-porous & porous surface through the powdering method. Here we use candle flame to collect black carbon mass and turn it into powder which is used for obtaining latent fingerprints. By the application of these powder it is observed that it gives a clear ridge on various surfaces. [ABSTRACT FROM AUTHOR]

A series of Schiff base LH ((E)-2-((pyridin-2-ylmethylene)amino)phenol) supported phenoxo bridged symmetric [Dy2(L)2(hfac)4] (1), [Dy2(L)2(tfac)4] (2) and asymmetric [Dy2(L)2(thd)3(NO3)]·1.5H2O (3) binuclear complexes were isolated using differently substituted β-diketonate co-ligands (Hhfac = hexafluoroacetylacetonate, Htfac = trifluoroacetylacetonate, and Hthd = 2,2,6,6-tetramethyl-3,5-heptanedione). In all the three complexes 1–3, the two LH ligands provide phenoxo bridging and N-donor atoms. The {Dy2(μ2-O)2} magnetic core structures with LH ligands are found to be the same in 1–3 while the dissimilar functionalities of the axially coordinated different β-diketonate co-ligands play a crucial role in modulating the magnetic anisotropy of individual DyIII sites and magnetic exchange between them. The experimental static magnetic behaviour suggests the presence of intramolecular antiferromagnetic interactions in all the three complexes 1–3. The strength of the magnetic exchange coupling decreases with increasing magnetic anisotropy of individual DyIII ions from complex 1 to complex 3 and simultaneously their zero-field slow magnetic relaxation behaviors were found to increase with effective energy barriers (ΔE/kB) of 9.04 K, 24.06 K and 25.65 K, respectively. Furthermore, the DFT and ab initio theoretical calculations performed on the X-ray structures of complexes 1–3 support our experimental findings. [ABSTRACT FROM AUTHOR]

A series of dinuclear lanthanide(III) complexes having general formulae [Ln2L2(thd)4] ⋅ 2CH3CN {Ln=DyIII(1), TbIII(2), GdIII(3), ErIII(4)} were successfully synthesized using Schiff base (E)‐2‐((pyridin‐2‐ylmethylene)amino)phenol (LH) and co‐ligand 2,2,6,6‐Tetramethyl‐3,5‐heptanedione (Hthd). The single crystal XRD data shows that complexes possess a dinuclear planar [Ln2(μ2‐O)2]4+ core where phenolate oxygen atoms act as bridges between the two LnIII ions, and that the coordination sphere of LnIII with eight coordination has distorted trigonal dodecahedron geometry. The magnetic analysis shows complex 1 is a single molecule magnet having a zero‐field effective energy barrier (Ueff) of 54.02 K and relaxation time of τo=4.45×10−6 s. Field‐induced SMM behavior has been observed for 4 with an effective energy barrier of 26.9 K and τ0=2.4×10−9 s. CASSCF+RASSI‐SO calculations on 1, 2 and 4 provide deep insight regarding the electronic structure and single‐ion anisotropy of lanthanide ions. Further, using state‐of‐the‐art ab initio calculations, the nature of magnetic anisotropy and magnetic exchange interaction between the LnIII centers is analyzed to shed light on the magnetic dynamics of all the complexes 1–4. [ABSTRACT FROM AUTHOR]

Five pentanuclear heterometallic isostructural complexes, [Ni4Ln(L)2(LH)2(CH3CN)3Cl]·xH2O·yCH3OH {Ln = YIII (1), GdIII (2), TbIII (3), DyIII (4) and ErIII (5)} [for 1 and 2, x = 2, y = 1; for 3, x = 6, y = 2; for 4, x = 5, y = 1; for 5, x = 2, y = 2] were prepared by the reaction of (E)‐2‐(hydroxymethyl)‐6‐{[(2‐hydroxyphenyl)imino]methyl}‐4‐methylphenol (LH3) with LnCl3·6H2O and Ni(OAc)2·4H2O in the presence of tetrabutylammonium hydroxide (TBA‐OH) base. The structural characterization reveals that compounds 1–5 contain a spirocyclic pentanuclear core [Ni4Ln(µ3‐O)4(µ2‐O)4]3+ where two triangular motifs [Ni2Ln(µ3‐O)2(µ2‐O)2]3+ are fused together through a common vertex of the LnIII ion. The central LnIII ion forms an eight‐coordinated distorted triangular dodecahedron geometry, while the nickel(II) ions form a distorted octahedron geometry. Comprehensive dc magnetic studies reveal that antiferromagnetic exchange interaction exists between the NiII centres. The ac susceptibility measurement revels that dysprosium and erbium analogue shows field induced slow magnetic relaxation with an anisotropic barrier (Ueff) of 25.12 cm–1 and 22.13 cm–1 respectively. [ABSTRACT FROM AUTHOR]

To study the effect of diamagnetic ions on magnetic interactions, utilizing a compartmental ligand ( Z )-2-(hydroxymethyl)-4-methyl-6-((quinolin-8-ylimino)methyl)phenol (LH 2 ), two different series of Zn II -Ln III complexes, namely the trinuclear series of [DyZn 2 (L) 2 (μ 2 -OAc) 2 (CH 3 OH) 2 ]·NO 3 ·MeOH (1), [TbZn 2 (L) 2 (μ 2 -OAc) 2 (CH 3 OH) 2 ]·NO 3 ·5MeOH·H 2 O (2), and [GdZn 2 (L) 2 (μ 2 -OAc) 2 (CH 3 OH) 2 ]·NO 3 ·MeOH·CHCl 3 (3) and the tetranuclear series of [Dy 2 Zn 2 (LH) 4 (NO 3 ) 4 (μ 2 OAc)]·NO 3 ·MeOH·H 2 O (4), [Tb 2 Zn 2 (LH) 4 (NO 3 ) 4 (μ 2 -OAc)]·NO 3 ·MeOH·2H 2 O (5), and [Gd 2 Zn 2 (LH) 4 (NO 3 ) 4 (μ 2 -OAc)]·NO 3 ·MeOH·2H 2 O (6), were synthesized. Trinuclear Zn II -Ln III complexes 1-3 consist of one Ln III ion sandwiched between two peripheral Zn II ions forming a bent type Zn II -Dy III -Zn II array with an angle of 110.64°. Tetranuclear Zn II -Ln III complexes 4-6 are basically a combination of two dinuclear moieties of [LnZn(LH) 2 (NO 3 ) 2 ] + connected by one bidentate bridging acetate ion in μ 2 -OAc coordination mode. The detailed magnetic analysis reveals that complexes 1 and 4 are single molecule magnets having energy barriers of 34.98 K and 46.71 K with relaxation times ( τ 0 ) of 5.05 × 10 -4 s and 5.24 × 10 -4 s, respectively. Ab initio calculations were employed to analyze the magnetic anisotropy and magnetic exchange interaction between the Zn II and Ln III centers with the aim of gaining better insights into the magnetic dynamics of complexes 1-6.

The reaction of Co(OAc) 2 ·6H 2 O with 2,2'-[{(1 E ,1' E )-pyridine-2,6-diyl-bis(methaneylylidene)bis(azaneylylidene)}diphenol](LH 2 ) a multisite coordination ligand and Et 3 N in a 1:2:3 stoichiometric ratio forms a tetranuclear complex Co 4 (L) 2 (μ-η 1 :η 1 -OAc) 2 (η 2 -OAc) 2 ]· 1.5 CH 3 OH· 1.5 CHCl 3 ( 1 ). Based on X-ray diffraction investigations, complex 1 comprises a distorted Co 4 O 4 cubane core consisting of two completely deprotonated ligands [L] 2- and four acetate ligands. Two distinct types of Co II centers exist in the complex, where the Co(2) center has a distorted octahedral geometry; alternatively, Co(1) has a distorted pentagonal-bipyramidal geometry. Analysis of magnetic data in 1 shows predominant antiferromagnetic coupling ( J = -2.1 cm -1 ), while the magnetic anisotropy is the easy-plane type ( D 1 = 8.8, D 2 = 0.76 cm -1 ). Furthermore, complex 1 demonstrates an electrochemical oxygen evolution reaction (OER) with an overpotential of 325 mV and Tafel slope of 85 mV dec -1 , required to attain a current density of 10 mA cm -2 and moderate stability under alkaline conditions (pH = 14). Electrochemical impedance spectroscopy studies reveal that compound 1 has a charge transfer resistance ( R ct ) of 2.927 Ω, which is comparatively lower than standard Co 3 O 4 (5.242 Ω), indicating rapid charge transfer kinetics between electrode and electrolyte solution that enhances higher catalytic activity toward OER kinetics.

A series of Schiff base LH (( E )-2-((pyridin-2-ylmethylene)amino)phenol) supported phenoxo bridged symmetric [Dy 2 (L) 2 (hfac) 4 ] (1), [Dy 2 (L) 2 (tfac) 4 ] (2) and asymmetric [Dy 2 (L) 2 (thd) 3 (NO 3 )]·1.5H 2 O (3) binuclear complexes were isolated using differently substituted β-diketonate co-ligands (Hhfac = hexafluoroacetylacetonate, Htfac = trifluoroacetylacetonate, and Hthd = 2,2,6,6-tetramethyl-3,5-heptanedione). In all the three complexes 1-3, the two LH ligands provide phenoxo bridging and N-donor atoms. The {Dy 2 (μ 2 -O) 2 } magnetic core structures with LH ligands are found to be the same in 1-3 while the dissimilar functionalities of the axially coordinated different β-diketonate co-ligands play a crucial role in modulating the magnetic anisotropy of individual Dy III sites and magnetic exchange between them. The experimental static magnetic behaviour suggests the presence of intramolecular antiferromagnetic interactions in all the three complexes 1-3. The strength of the magnetic exchange coupling decreases with increasing magnetic anisotropy of individual Dy III ions from complex 1 to complex 3 and simultaneously their zero-field slow magnetic relaxation behaviors were found to increase with effective energy barriers (Δ E / k B ) of 9.04 K, 24.06 K and 25.65 K, respectively. Furthermore, the DFT and ab initio theoretical calculations performed on the X-ray structures of complexes 1-3 support our experimental findings.