Synthesis, mixed-spin-state structure and Langmuir-Blodgett deposition of amphiphilic Fe(iii) quinolylsalicylaldiminate complexes.

Designing and integrating Fe(iii)-based spin crossover (SCO) complexes onto substrates remains a challenging goal with only a handful of examples reported. In this work, we successfully synthesized and characterized three [Fe(qsal-OR)]NO (qsal-OR = 5-alkoxy-2-[(8-quinolylimino)methyl]phenolate) complexes, in which R = CH1, CH2, and CH3 to explore the impact of alkyl chain on the modulation of SCO activity and potential for self-assembly on a glass surface. The SCO is found to be gradual and incomplete in all cases, with the LS state more stabilised as the alkyl group shortens.

Thermal Jahn-Teller Distortion Changes and Slow Relaxation of Magnetization in Mn(III) Schiff Base Complexes.

The impact that the anion and alkyl group has on the electronic structures and magnetic properties of four mononuclear Mn(III) complexes is explored in [Mn(salEen-Br)]Y (salEen-Br = 2-{[2-(ethylamino)ethylimino]methyl}-4-Br-phenol; Y = ClO and BF·1/3CHCl ) and [Mn(salBzen-Br)]Y (salBzen-Br = 2-{[2-(benzylamino)ethylimino]methyl}-4-Br-phenol; Y = ClO and BF ). X-ray structures of [Mn(salEen-Br)]ClO·0.45CH , [Mn(salEen-Br)]BF·0.

Antibacterial and antibiofilm efficacy of Solanum lasiocarpum root extract synthesized silver/silver chloride nanoparticles against Staphylococcus haemolyticus associated with bovine mastitis.

Staphylococcus haemolyticus is a cause of bovine mastitis, leading to inflammation in the mammary gland. This bacterial infection adversely affects animal health, reducing milk quality and yield. Its emergence has been widely reported, representing a significant economic loss for dairy farms.

Improving spin crossover characteristics in heteroleptic [Fe(qsal-5-I)(qsal-5-OMe)]A complexes.

A family of heteroleptic spin crossover (SCO) [Fe(qsal-5-I)(qsal-5-OMe)]A·sol (qsal-5-X = 5-X-2-[(8-quinolylimino)methyl]phenolate; A = NO1 sol = 2MeOH, NCS2 sol = 0.75MeOH·1.3HO, BF3 sol = MeOH, OTf4, sol = MeOH) complexes have been synthesized.

Bidirectional photoswitchability in an iron(iii) spin crossover complex: symmetry-breaking and solvent effects.

The impact of solvent on spin crossover (SCO) behaviour is reported in two solvates [Fe(qsal-I)]NO·2ROH (qsal-I = 4-iodo-2-[(8-quinolylimino)methyl]phenolate; R = Me 1 or Et 2) which undergo abrupt and gradual SCO, respectively. A symmetry-breaking phase transition due to spin-state ordering from a [HS] to [HS-LS] state occurs at 210 K in 1, while = 250 K for the EtOH solvate, where complete SCO occurs. The MeOH solvate exhibits LIESST and -LIESST from the [HS-LS] state, revealing a hidden [LS] state.

Preparation and physicochemical characterization of sildenafil cocrystals.

Sildenafil is a specific inhibitor of the phosphodiesterase type 5 (PDE-5) enzyme that protects cyclic guanosine monophosphate from breakdown by PDE-5. It is a biopharmaceutical categorization system Class II medication with low bioavailability because it is almost insoluble in water. The objectives of this study were to prepare sildenafil cocrystals with co-former molecules including aspirin (acetylsalicylic acid [ASA]), fumaric acid (FMA), and benzoic acid (BZA) to improve the water solubility of sildenafil.

Room temperature conductance switching in a molecular iron(iii) spin crossover junction.

Herein, we report the first room temperature switchable Fe(iii) molecular spin crossover (SCO) tunnel junction. The junction is constructed from [Fe(qsal-I)]NTf (qsal-I = 4-iodo-2-[(8-quinolylimino)methyl]phenolate) molecules self-assembled on graphene surfaces with conductance switching of one order of magnitude associated with the high and low spin states of the SCO complex. Normalized conductance analysis of the current-voltage characteristics as a function of temperature reveals that charge transport across the SCO molecule is dominated by coherent tunnelling.

Synthesis, characterization and anticancer activity of Fe(II) and Fe(III) complexes containing N-(8-quinolyl)salicylaldimine Schiff base ligands.

A series of Fe(II) complexes (1-4) and Fe(III) complexes (5-8) from Fe(II)/(III) chloride and N-(8-quinolyl)-X-salicylaldimine Schiff base ligands (Hqsal-X/X: X = Br, Cl) were successfully synthesized and characterized by spectroscopic (FT-IR, H-NMR), mass spectrometry, thermogravimetric analysis (TGA), and single crystal X-ray crystallographic techniques. The interaction of complexes 1-8 with calf thymus DNA (CT-DNA) was determined by UV-Vis and fluorescence spectroscopy. The complexes exhibited good DNA-binding activity via intercalation.

OctaDist: a tool for calculating distortion parameters in spin crossover and coordination complexes.

OctaDist is an interactive and visual program for determination of structural distortion in octahedral coordination complexes such as spin crossover complexes, single-ion magnets, perovskites or metal-organic frameworks. OctaDist computes the octahedral distortion parameters initially designed in the context of the spin-crossover phenomenon and denoted ζ, Σ, and Θ from standard structural files. The program also provides additional tools for molecular analyses and visualization.

Conformational polymorphism in a cobalt(II) dithiocarbamate complex.

Two conformational polymorphs of (N,N-dibutyldithiocarbamato-κS,S')[tris(3,5-diphenylpyrazol-1-yl-κN)hydroborato]cobalt(II), [Co(CHBN)(CHNS)] or [TpCo(SCNBu)], 1, are accessible by recrystallization from dichloromethane-methanol to give orthorhombic polymorph 1a, while slow evaporation from acetonitrile produces triclinic polymorph 1b. The two polymorphs have been characterized by IR spectroscopy and single-crystal X-ray crystallography at 150 K. Polymorphs 1a and 1b crystallize in the orthorhombic space group Pbca and the triclinic space group P-1, respectively.

Spin Crossover in Iron(III) Quinolylsalicylaldiminates: The Curious Case of [Fe(qsal-F)](Anion).

A family of iron(III) spin crossover complexes with different counteranions, [Fe(qsal-F)]A (qsal-F = 4-fluoro-2-[(8-quinolylimino)methyl]phenolate; A = PF , OTf , NO , ClO , BF , or NCS ) have been prepared. All compounds are isostructural and crystallize (triclinic 1̅ space group) with two independent iron(III) centers (Fe1 and Fe2) in the asymmetric unit. No solvent molecules are found in the crystal lattice, allowing us to directly probe the relative influence of anion variation on the spin crossover characteristics.

Abrupt spin crossover in iron(iii) complexes with aromatic anions.

Two iron(iii) spin crossover complexes, [Fe(qsal-X)]OTs·nHO, (Br 1·HO; I, 2·2HO or non-solvated 1, 2) have been prepared and fully characterized. Structural studies of 1·HO and 2·2HO reveal the presence of 1D π-π chains linking the Fe(iii) centres and a strong XO halogen bond. In both complexes the 1D π-π chains are angled relative to each other, enforced by C-HX interactions.

The First Observation of Hidden Hysteresis in an Iron(III) Spin-Crossover Complex.

Molecular magnetic switches are expected to form the functional components of future nanodevices. Herein we combine detailed (photo-) crystallography and magnetic studies to reveal the unusual switching properties of an iron(III) complex, between low (LS) and high (HS) spin states. On cooling, it exhibits a partial thermal conversion associated with a reconstructive phase transition from a [HS-HS] to a [LS-HS] phase with a hysteresis of 25 K.

Solvatomorphism and anion effects in predominantly low spin iron(iii) Schiff base complexes.

A series of iron(iii) complexes [Fe(naphEen)2]X·sol (naphEen = 1-{[2-(ethylamino)-ethylimino]methyl}-2-naphtholate; X = F, sol = 0.5CH2Cl2·H2O 1; sol = H2O, X = Cl, 2 and X = Br 3) and [Fe(naphEen)2]I 4 has been prepared. The UV-Vis spectra reveal clear differences for 1 which DFT/TDDFT calculations suggest are due to an equilibrium between [Fe(naphEen)2]F and [Fe(naphEen)2F], the latter having a coordinated F ligand.

Self-assembly of a mixed-valence Fe-Fe tetranuclear star.

A unique self-assembled mixed-valence FeII-FeIII tetranuclear star has been comprehensively characterised showing a large magnetic anisotropy at the peripheral FeII centres, ferromagnetic coupling between the iron centres and field-induced SMM behaviour.

Slow relaxation of magnetization in a bis-mer-tridentate octahedral Co(ii) complex.

Reaction of a rigid tridentate ligand o-[(1H-imidazol-2-yl)methylideneamino]phenol (2-Himap) with Co(ClO) in the presence of NaN, or Co(NO) without a base yields [Co(2-Himap)] 1 and [Co(2-Himap)]NO·MeOH 2, respectively. Both complexes exhibit a mer-octahedral geometry with the cobalt centre being distorted along an octahedral-trigonal prismatic pathway. The packing in 1 and 2 is dominated by H-bonding forming 2D sheets and 1D chains, respectively.

Hysteretic spin crossover driven by anion conformational change.

A new air stable Fe spin crossover (SCO) complex has been synthesized. The compound undergoes abrupt SCO near room temperature with T (↓) = 244 K and T (↑) = 278 K. Structural studies of the complex in the high spin and low spin state show that the strong cooperativity and thus the wide hysteresis is driven by an unprecedented anionic conformational change.

Solvent modified spin crossover in an iron(iii) complex: phase changes and an exceptionally wide hysteresis.

Solvent effects in a series of Fe(iii) spin crossover (SCO) complexes [Fe(qsal-I)]OTf·sol (sol = MeOH , EtOH , -PrOH , i-PrOH , acetone and MeCN ) are explored. SCO is abrupt in (following MeOH loss) and , gradual for ( = 199 K) and ( = 251 K) and incomplete, even up to 350 K, for and . In [Fe(qsal-I)]OTf SCO occurs at ↓ = 225 K and ↑ = 234 K (Δ = 9 K), while aged samples of exhibit an exceptionally wide hysteresis of 80 K (↓ = 139 K and ↑ = 219 K).

Abrupt two-step and symmetry breaking spin crossover in an iron(III) complex: an exceptionally wide [LS-HS] plateau.

[Fe(qsal-Br)2]NO3·2MeOH is reported which undergoes abrupt two step symmetry breaking spin crossover, T½(1st step) = 136 K and T½(2nd step) = 232 K with a hysteresis of 16 K and 5 K, respectively, and an unprecedented [HS-LS] plateau of 96 K.

Stepped spin crossover in Fe(III) halogen substituted quinolylsalicylaldimine complexes.

The reaction of Fe(NCS)3 prepared in situ in MeOH with Hqsal-X (Hqsal-X = 5-X-N-quinolylsalicylaldimine) in CH2Cl2 yields the FeIII complexes, [Fe(qsal-X)2]NCS·solvent (X = F 1; X = Cl, 2, Br, 3 solvent = MeOH; X = I, solvent = 0.25CH2Cl2·0.5MeOH 4) in moderate to good yields.

Abrupt spin crossover in an iron(III) quinolylsalicylaldimine complex: structural insights and solvent effects.

The first Fe(III) qsal-X complex exhibiting abrupt complete spin crossover at 228 K with a hysteresis of 8 K, [Fe(qsal-I)2]OTf is reported. Structural studies of the MeOH solvate in the LS and HS state and at the spin transition are described.

Fe(III) quinolylsalicylaldimine complexes: a rare mixed-spin-state complex and abrupt spin crossover.

A new synthesis of (8-quinolyl)-5-methoxysalicylaldimine (Hqsal-5-OMe) is reported and its crystal structure is presented. Two Fe(III) complexes, [Fe(qsal-5-OMe)(2)]Cl⋅solvent (solvent = 2 MeOH⋅0.5 H(2)O (1) and MeCN⋅H(2)O (2)) have been prepared and their structural, electronic and magnetic properties studied.

(8-Amino-quinoline-κ(2)N,N')bis-(1,1,1,5,5,5-hexa-fluoro-pentane-2,4-dionato-κ(2)O,O')cobalt(II).

In the title compound, [Co(C(5)HF(6)O(2))(2)(C(9)H(8)N(2))], the Co(II) centre exhibits a pseudooctahedral coordination geometry, comprising two N-atom donors from the bidentate amino-quinoline ligand and four O-atom donor atoms from two bidentate chelating 1,1,1,5,5,5-hexafluoropentane-2,4-dionate ligands. In the crystal, molecules are linked via pairs of N-H⋯O hydrogen bonds, forming inversion dimers. These dimers are further connected through π-π interactions between neighbouring quinoline rings [centroid-centroid distance = 3.

(Di-2-pyridyl-amine-κN,N')[hydro-tris-(3,5-diphenyl-pyrazol-1-yl-κN)borato]nickel(II) bromide dichloro-methane monosolvate.

In the title compound, [Ni(C(45)H(34)BN(6))(C(10)H(9)N(3))]Br·CH(2)Cl(2), the Ni(II) atom is five-coordinated by the tridentate hydro-tris-(3,5-diphenyl-pyrazol-yl)borate ligand and a bidentate di-2-pyridyl-amine ligand in a distorted square-pyramidal geometry. In the crystal, inter-molecular N-H⋯Br and C-H⋯Br hydrogen bonds link the Ni complex cations and the Br(-) ions, forming a chain along the c axis.

[4-Bromo-N-(pyridin-2-yl-methyl-idene)aniline-κN,N']bis-(1,1,1,5,5,5-hexa-fluoro-pentane-2,4-dionato-κO,O')nickel(II).

The title compound, [Ni(C(5)HF(6)O(2))(2)(C(12)H(9)BrN(2))], the Ni(II) atom exhibits a pseudo-octa-hedral coordination geometry. The structure packs through C-H⋯Br inter-actions, forming a hydrogen-bonded ladder. There are also strong hydrogen-bonding inter-actions between two of the O atoms of the β-diketonate ligands and two H atoms on the pyridine ring of the Schiff base ligand.