Isostructural Oxamate Complexes with Visible Luminescence (Eu) and Field-Induced Single-Molecule Magnet (Nd).

The search for new metal-organic compounds as candidates for quantum information processing technologies is in the spotlight. Several metal ions and organic linkers have been used to obtain such compounds. Herein, we describe the synthesis, crystal structures, and cryomagnetic properties of two air-stable isostructural neodymium(III) and europium(III) one-dimensional (1D) coordination polymers of formula [Nd(Hmpa)(DMSO)] (1) and [Eu(Hmpa)(DMSO)] (2) [Hmpa=N-(4-methylphenyl)oxamate, and DMSO=dimethylsulfoxide].

Crystal structures of two unexpected products of vicinal diamines left to crystallize in acetone.

Herein we report the crystal structures of two benzodiazepines obtained by reacting N,N'-(4,5-diamino-1,2-phenylene)bis(4-methylbenzenesulfonamide) (1) or 4,5-(4-methylbenzenesulfonamido)benzene-1,2-diaminium dichloride (1·2HCl) with acetone, giving 2,2,4-trimethyl-8,9-bis(4-methylbenzenesulfonamido)-2,3-dihydro-5H-1,5-benzodiazepine, CHNOS (2), and 2,2,4-trimethyl-8,9-bis(4-methylbenzenesulfonamido)-2,3-dihydro-5H-1,5-benzodiazepin-1-ium chloride 0.3-hydrate, CHNOS·Cl·0.3HO (3).

Photoluminescence and magnetic properties of isostructural europium(III), gadolinium(III) and terbium(III) oxamate-based coordination polymers.

Developing and investigating advanced multifunctional materials with magnetic properties as candidates for assembling spin qubits for quantum computing is imperative. A new polytopic ligand based on oxamate and aniline was used to promote the synthesis of three neutral homometallic lanthanide-coordinated polymers. New complexes with the formula {Ln(phox)(DMSO)(HO)}, where Ln = Eu (1), Gd (2), and Tb (3) [phox = -(phenyl)oxamate and DMSO = dimethylsulfoxide], were synthesized and well characterized by spectroscopic methods as well as X-ray crystallographic analysis.

Crystal structure and cryomagnetic study of a mononuclear erbium(III) oxamate inclusion complex.

The synthesis, crystal structure and magnetic properties of an oxamate-containing erbium(III) complex, namely, tetrabutylammonium aqua[N-(2,4,6-trimethylphenyl)oxamato]erbium(III)-dimethyl sulfoxide-water (1/3/1.5), (CHN)[Er(CHNO)(HO)]·3CHOS·1.5HO or n-BuN[Er(Htmpa)(HO)]·3DMSO·1.

Hexamethylenetetramine-tridecanedioic acid (1/1): temperature-induced order-disorder structural phase transitions with phase co-existence.

The cocrystal hexamethylenetetramine-tridecanedioic acid (1/1) (HMT-C13), CHN·CHO, was investigated by single-crystal X-ray diffraction techniques at several temperatures during cooling and heating processes. Our results show the formation of two crystalline phases, separated by a large temperature phase co-existence between 290 and 340 K. Phase I, stable above 341 K, presents an orthorhombic structure described in the space group Bmmb, with one N(CH)·CHO adduct in its asymmetric unit.

Unexpected formation of a dodecanuclear {CoII6CuII6} nanowheel under ambient conditions: magneto-structural correlations.

We report the unique heterobimetallic dodecanuclear oxamate-based {CoII6CuII6} nanowheel obtained using an environmentally friendly synthetic protocol. The effective Hamiltonian methodology employed herein allows the rationalisation of magnetic isotropic or anisotropic metal clusters, being a significant advance for future studies of exciting properties only observed at low and ultralow temperatures.

Field-Induced Slow Magnetic Relaxation of a Six-Coordinate Mononuclear Manganese(II) and Cobalt(II) Oxamate Complexes.

Two air-stable, isostructural, mononuclear six-coordinate manganese(II) and cobalt(II) oxamate complexes, [(4-HOpa)(HO)] [4-HOpa = -4-hydroxyphenyloxamate; = Mn () or Co ()], exhibit field-induced slow magnetic relaxation. A bottleneck process is observed throughout the temperature range of 2-20 K for , while for , it dominates only at low temperatures (2-4 K). Additionally, the Raman process [ = 6.

Mononuclear lanthanide(III)-oxamate complexes as new photoluminescent field-induced single-molecule magnets: solid-state photophysical and magnetic properties.

Implementing additional optical (luminescent) properties into the well-known class of single-molecule magnets (SMMs) is considered as a promising route toward obtaining the next generation of optomagnetic materials for quantum information storage and computing. Herein, we report a joint optical and magneto-structural study for the two novel series of lanthanide(iii) complexes of general formula Bu4N[LnIII(HL)4(dmso)]·nH2O where H2L = N-(4-Xphenyl)oxamic acid with X = Cl and n = 2 [Ln = Eu (1_Cl), Gd (2_Cl), Dy (3_Cl), and Tb (4_Cl)] and X = F and n = 3 [Ln = Eu (1_F), Gd (2_F), Dy (3_F), and Tb (4_F)]. All these compounds are mononuclear species with each lanthanide(iii) cation in a low-symmetry nine-coordinate environment (LnO9) which is constituted by four didentate monoprotonated oxamate groups and one dmso molecule.

Combination of Aryl Diselenides/Hydrogen Peroxide and Carbon-Nanotube/Rhodium Nanohybrids for Naphthol Oxidation: An Efficient Route towards Trypanocidal Quinones.

This work reports a combination of aryl diselenides/hydrogen peroxide and carbon-nanotube (CNT)/rhodium nanohybrids (RhCNT) for naphthol oxidation towards the synthesis of 1,4-naphthoquinones and evaluation of their relevant trypanocidal activity. Under a combination of (PhSe) /H O in the presence of O in iPrOH/hexane, several benzenoid (A-ring)-substituted quinones were prepared in moderate to high yields. We also studied the contribution of RhCNT as co-catalyst in this process and, in some cases, yields were improved.

Design of 3d-4f molecular squares through the [Fe{(HB(pz))}(CN)] metalloligand.

A new series of {FeIII2LnIII2} heterobimetallic squares of general formula [FeIII{HB(pz)3}(CN)(μ-CN)2Ln(pyim)x(NO3)2(H2O)y]2·zH2O [Ln = La (1), Gd (2), Tb (3) and Dy (4); {HB(pz)3}- = hydrotris(pyrazolyl)borate and pyim = 2-(1H-imidazol-2-yl)pyridine; x = 2, y = 0 (1), x = y = 1 (2-4) and z = 10 (1), 6 (2), 2.76 (3), 4 (4)] were synthesized by reacting the low-spin [FeIII{HB(pz)3}(CN)3]- complex anion with the preformed [LnIII(pyim)x(NO3)2(H2O)y]+ complex cation [formed in situ by mixing the lanthanide(iii) salt and the pyim ligand]. Single-crystal X-ray diffraction shows that 1-4 crystallize in the P1[combining macron] triclinic space group, 2-4 being isomorphous.

Direct sequential C-H iodination/organoyl-thiolation for the benzenoid A-ring modification of quinonoid deactivated systems: a new protocol for potent trypanocidal quinones.

We report a sequential C-H iodination/organoyl-thiolation of naphthoquinones and their relevant trypanocidal activity. Under a combination of AgSR with a copper source, sulfur-substituted benzenoid quinones were prepared in high yields (generally >90%). This provides an efficient and general method for preparing A-ring modified naphthoquinoidal systems, recognized as a challenge in quinone chemistry.

Photoluminescent and Slow Magnetic Relaxation Studies on Lanthanide(III)-2,5-pyrazinedicarboxylate Frameworks.

In the series described in this work, the hydrothermal synthesis led to oxidation of the 5-methyl-pyrazinecarboxylate anion to the 2,5-pyrazinedicarboxylate dianion (2,5-pzdc) allowing the preparation of three-dimensional (3D) lanthanide(III) organic frameworks of formula {[Ln(2,5-pzdc)(HO)]·6HO} [Ln = Ce (1), Pr (2), Nd (3), and Eu (4)] and {[Er(2,5-pzdc)(HO)]·5HO} (5). Single-crystal X-ray diffraction on 1-5 reveals that they crystallize in the triclinic system, P1̅ space group with the series 1-4 being isostructural. The crystal structure of the five compounds are 3D with the lanthanide(III) ions linked through 2,5-pzdc dianions acting as two- and fourfold connectors, building a binodal 4,4-connected (4·68)(468)-mog network.

Magneto-structural versatility of copper(II)-3-phenylpropionate coordination polymers with N-donor coligands.

A novel series of copper(II) coordination polymers [Cu2(O2CC8H9)4(pyz)]n (1), [Cu2(O2CC8H9)4(dps)]n (2), {[Cu(O2CC8H9)2(dps)(H2O)]·H2O}n (3), {[NaCu(O2CC8H9)2(bpm)(NO3)]·H2O}n (4), and [Cu4(O2CC8H9)6(OH)2(bpp)2]n (5) [O2CC8H9− = 3-phenylpropionate anion, pyz = pyrazine, dps = di(4-pyridyl)sulfide, bpm = 2,2′-bipyrimidine, and bpp = 1,3-bis(4-pyridyl)propane] have been synthesized and magneto-structurally investigated. Compounds 1 and 2 belong to a large group of copper(II) carboxylates where bis-monodentate pyz (1) and dps (2) ligands connect the paddle-wheel [CuII2(μ-O2CC8H9)4] units leading to alternating copper(II) chains. The structure of 3 consists of uniform chains of trans-[CuII(O2CC8H9)2] units linked by the bis-monodentate dps ligand.

Relatively strong intramolecular antiferromagnetic coupling in a neutral Cr(III)2Nb(V)2 heterobimetallic molecular square.

A relatively large antiferromagnetic interaction between the two chromium(III) ions from the molecular square [{Cr(dmso)4}2{Nb(μ-O)2(C2O4)2}2] () (J = -12.0 cm(-1)) is mediated by the diamagnetic oxo-Nb(V)-oxo pathway, its nature and magnitude being substantiated by DFT type theoretical calculations.

A heterobimetallic [Mn₅(II)Cu₅(II)] nanowheel modulated by a flexible bis-oxamate type ligand.

The synthesis, crystal structure and preliminary magnetic characterization of a new heterobimetallic [Mn₅(II)Cu₅(II)] wheel containing a flexible bis-oxamate type ligand are described. This decanuclear compound exhibits a relatively strong intra-wheel antiferromagnetic interaction leading to a ground spin state S = 10.

A pH-triggered bistable copper(II) metallacycle as a reversible emulsion switch for biphasic processes.

A unique bistable copper-metallacyclic complex is used as an elegant molecular switch for the reversible formation of emulsions by simple pH variation. This switch may have several exciting applications in biphasic processes such as catalysis and separation science technologies.

The structure of the 1H-imidazol-3-ium lawsonate salt aided by ab initio gas-phase calculations.

For the new organic salt 1H-imidazol-3-ium 1,4-dioxo-1,4-dihydronaphthalen-2-olate, C3H5N2(+)·C10H5O3(-), ab initio calculations of the gas-phase structures of the lawsonate and imidazolium ions were performed to help in the interpretation of the structural features observed. Three different types of hydrogen bond are responsible for the three-dimensional packing of the salt.