Exploring structural, magnetic, and catalytic diversity in tetranuclear {CuO} cubane cores and a dinuclear complex derived from closely related ligand systems.

The coordination compounds featuring a {CuO} core, typically bridged by hydroxo or alkoxo groups, are particularly intriguing due to their notable magnetic properties and catalytic activity. In this study, we explored the synthesis and characterization of four new Schiff base ligands and their subsequent complexation with Cu salts, which resulted in the formation of three tetranuclear complexes: [Cu(L)]·2HO (1), [Cu(L)(HL)](Cl)(NO)·5HO (2), and [Cu(L)] (3), as well as one dinuclear complex: [Cu(L)] (4). These tetranuclear complexes all feature a {CuO} core, but with differing coordination environments around the Cu centers.

Supramolecular Dimeric Mn Complexes: Synthesis, Structure, Magnetic Properties, and Catalytic Oxidation Studies.

In this study, a tetradentate Schiff-base ligand (HL), synthesized by the condensation of ethylenediamine with 2-hydroxy-3-methoxy-5-methylbenzaldehyde, was reacted with either manganese salts or manganese salts in the presence of various pseudohalides in methanol. This reaction resulted in the formation of five mononuclear Mn complexes: [Mn(L)(HO)](NO)·1/2HO·1/2CHOH (), [Mn(L)(HO)](ClO)·HO (), [Mn(L)(N)(HO)]·1/3HO (), [Mn(L)(NCS)(HO)] (), and [Mn(L)(HO)](dca) () (where dca is dicyanamide ion). X-ray crystallography revealed that the Mn centers adopt a hexa-coordinate pseudo-octahedral geometry, where the equatorial plane is constructed with phenoxo oxygen and imine nitrogen atoms from the Schiff base ligand, while the axial positions are occupied by water molecules or a combination of water and pseudohalides.

The effect of co-ligands on the performance of single-molecule magnet behaviours in a family of linear trinuclear Zn-Dy-Zn complexes with a compartmental Schiff base.

We present herein magneto-structural studies of three heterometallic ZnDy complexes: [ZnDy(L)Cl(HO)](ClO)·4HO (1), [ZnDy(L)Br(HO)](ClO)·4HO (2) and [ZnDy(L)(OAc)I(HO)]I·4HO (3), utilizing a new Schiff base ligand, ,-bis(3-methoxy-5-methylsalicylidene)-1,2-diaminocyclohexane (HL). Complexes 1 and 2 exhibit remarkable magnetic relaxation behaviour with relatively high energy barriers in zero field (: 244 K for 1 and 211 K for 2) and notable hysteresis temperatures, despite the low local geometric symmetry around the central Dy ions. The SMM performance of these complexes is further enhanced under an applied magnetic field, with increasing to 309 K for 1 and 269 K for 2, positioning them as elite members within the Zn-Dy SMM family.

Chemical fixation of atmospheric CO in tricopper(II)-carbonato complexes with tetradentate N-donor ligands: reactive intermediates, probable mechanisms, and catalytic and magneto-structural studies.

In the present era, the fixation of atmospheric CO is of significant importance and plays a crucial role in maintaining the balance of carbon and energy flow within ecosystems. Generally, CO fixation is carried out by autotrophic organisms; however, the scientific community has paid substantial attention to execute this process in laboratory. In this report, we synthesized two carbonato-bridged trinuclear copper(II) complexes, [Cu(L1)(μ-CO)](ClO) (1) and [Cu(L2)(μ-CO)](ClO) (2) atmospheric fixation of CO starting with Cu(ClO)·6HO and easily accessible pyridine/pyrazine-based N donor Schiff base ligands L1 and L2, respectively.

Insight into ferromagnetic interactions in Cu-Ln dimers with a compartmental ligand.

In the last two decades, efforts have been devoted to obtaining insight into the magnetic interactions between Cu and Ln utilizing experimental and theoretical means. Experimentally, it has been observed that the exchange coupling () in Cu-Ln systems is often found to be ferromagnetic for ≥4f metal ions. However, exchange interactions at sub-Kelvin temperatures between Cu and the anisotropic/isotropic Ln ions are not often explored.

Magneto-structural studies on a number of doubly end-on cyanate and azide bridged dinuclear nickel(ii) complexes with {NO} donor Schiff base ligands.

Two new doubly -N bridged (1 and 3) and six new doubly -NCO bridged Ni complexes (2, 4-8) with six different NO donor Schiff base ligands have been synthesized and magneto-structurally characterized. All these neutral complex molecules are isostructural and constitute edge sharing bioctahedral structures. Magnetic studies revealed that all these complexes exhibit ferromagnetic interaction through bridging pseudohalides with ferromagnetic coupling constant being significantly higher for azide-bridged complexes than that of the cyanate analogues.

Combined experimental and theoretical studies on a series of mononuclear Ln single-molecule magnets: dramatic influence of remote substitution on the magnetic dynamics in Dy analogues.

A series of Ln complexes of general formula [Ln(HL)(NO)(HO)](NO) (1-5) [Ln = Dy (1), Tb (2) Ho (3), Er (4), and Yb (5)] and an analogous Dy complex with ligand HL, [Dy(HL)(NO)(HO)](NO) (6), where HL and HL stand for ()-2-[(2-hydroxyphenyl)iminomethyl]-6-methoxy-4-methylphenol and ()-2-[(2-hydroxy-5-methylphenyl)iminomethyl]-6-methoxy-4-methylphenol, respectively, have been synthesized and magneto-structurally characterized. All these complexes are isostructural and isomorphous, in which the zwitterionic form of the ligands predominantly coordinate the metal centers. The magnetic study revealed that complex 3 displays negligible SMM behaviour, while 1 and 6 are zero field SMMs, the performance of which can largely be improved in the presence of an applied dc field by lowering under barrier relaxation processes, and finally 2, 4, and 5 are field-induced SMMs.

Two rhodamine-azo based fluorescent probes for recognition of trivalent metal ions: crystal structure elucidation and biological applications.

Two rhodamine and azo based chemosensors (HL1 = (3',6'-bis(ethylamino)-2-((2-hydroxy-3-methoxy-5-(phenyldiazenyl)benzylidene)amino)-2',7'-dimethylspiro[isoindoline-1,9'-xanthen]-3-one) and HL2 = (3',6'-bis(ethylamino)-2-(((2-hydroxy-3-methoxy-5-(-tolyldiazenyl)benzylidene)amino)-2',7'-dimethylspiro[isoindoline-1,9'-xanthen]-3-one) have been synthesized for colorimetric and fluorometric detection of three trivalent metal ions, Al, Cr and Fe. The chemosensors have been thoroughly characterized by different spectroscopic techniques and X-ray crystallography. They are non-fluorescent due to the presence of a spirolactam ring.

Proton controlled synthesis of two dicopper(II) complexes and their magnetic and biomimetic catalytic studies together with probing the binding mode of the substrate to the metal center.

This paper describes the synthesis, and structural and spectroscopic characterizations of two doubly bridged dicopper(II) complexes, [Cu(μ-HL)(μ-OMe)](ClO)·2HO (1) and [Cu(μ-L)(μ-OH)](ClO) (2), with a binucleating ligand (HL) derived from the Schiff base condensation of DFMP and ,-dimethyldipropylenetriamine, and their biomimetic catalytic activities were related to CAO and phenoxazinone synthase using 3,5-di--butylcatechol and -aminophenol (OAPH), respectively, as model substrates. Structural studies reveal that the major differences in these structures appear to be from the distinct roles of the tertiary amine groups of the ligands, which are protonated in 1, whereas it coordinates the metal centers in 2. Magnetic studies disclose that two copper(II) centers are strongly antiferromagnetically coupled with slightly different values, which is further interpreted and discussed.

Macrocycle supported dimetallic lanthanide complexes with slow magnetic relaxation in Dy analogues.

Six dimetallic lanthanide complexes, [Ln2(L')(acac)4] (1Dy-3Gd) (Ln = Dy (1Dy), Tb (2Tb) and Gd (3Gd)) and [Ln2(L')(tfac)4] (4Dy-6Gd) (Ln = Dy (4Dy), Tb (5Tb) and Gd (6Gd)) (H2L' = 1,9-dichloro-3,7,11,15-tetraaza-1,9(1,3)-dibenzenacyclohexadecaphane-2,10-diene-1,9-diol), have been synthesized by the reaction of lanthanide nitrates with the HL ligand in the presence of acetylacetonate (acac) (or trifluoroacetylacetonate (tfac) and triethylamine (HL = 4-chloro-2,6-bis(-((3-((3-(dimethylamino)propyl)amino)propyl)imino)methyl)phenol). Ln-Assisted modification of the Schiff base HL occurred and led to the formation of a new macrocyclic ligand (H2L'). X-ray crystallographic analysis revealed that the LnIII ions of complexes 1Dy-6Gd are all eight-coordinated in a square antiprismatic geometry with D4d local symmetry.

A facile biomimetic catalytic activity through hydrogen atom abstraction by the secondary coordination sphere in manganese(III) complexes.

This paper describes the synthesis and structural characterization of four new manganese(iii) complexes (1-4) derived from N3O donor Schiff base ligands and their biomimetic catalytic activities related to catechol oxidase and phenoxazinone synthase. X-ray crystallography reveals that the Schiff bases coordinate the metal centre in a tridentate fashion, leaving the pendant tertiary amine nitrogen atom either protonated or free to balance the charge of the system, and these pendant triamines participate in strong hydrogen bonding interactions in the solid state. The hydrogen bonding ability of the pendant triamines at the second coordination sphere plays a crucial role in the substrate recognition and the stability of the complex-substrate intermediates.

Prognosis of depression.

Relationship of different symptoms, personal history, some measures of Rorschach, neuroticism, ego strength score with prognosis of depression was studied. Out of 60 items studied in 60 cases, eleven were found to have statistically significant association with improvement. Multiple regression of percentage of improvement on 23 items (12 from personal and family history and 13 measurable items of Rorschach) was determined.