Melatonin as a Therapy for Preterm Brain Injury: What Is the Evidence?

Despite significant improvements in survival following preterm birth in recent years, the neurodevelopmental burden of prematurity, with its long-term cognitive and behavioral consequences, remains a significant challenge in neonatology. Neuroprotective treatment options to improve neurodevelopmental outcomes in preterm infants are therefore urgently needed. Alleviating inflammatory and oxidative stress (OS), melatonin might modify important triggers of preterm brain injury, a complex combination of destructive and developmental abnormalities termed encephalopathy of prematurity (EoP). Preliminary data also suggests that melatonin has a direct neurotrophic impact, emphasizing its therapeutic potential with a favorable safety profile in the preterm setting. The current review outlines the most important pathomechanisms underlying preterm brain injury and correlates them with melatonin’s neuroprotective potential, while underlining significant pharmacokinetic/pharmacodynamic uncertainties that need to be addressed in future studies

A new approach towards ferromagnetic conducting materials based on TTF-containing polynuclear complexes

International audienceFive complexes containing binuclear cation [Cu2(LH)2]2+ (LH2 = 1 : 2 Schiff base of 1,3-diaminobenzene and butanedione monoxime) were prepared and characterized. Metathesis of one perchlorate anion in [Cu2(LH)2(H2O)2](ClO4)2 (1) by anionic TTF-carboxylate (TTF-CO2−) leads to the complex [Cu2(LH)2(CH3OH)2](TTF-CO2)(ClO4)*H2O (2). Reactions of 1 with substituted pyridines bipy, dpe and TTF-CH = CH-py result in formation of the complexes {[Cu2(LH)2(bipy)](ClO4)2}n*2nH2O (3), [Cu2(LH)2(dpe)2](ClO4)2*2CH3OH (4) and [Cu2(LH)2(TTF-CH = CH-py)(H2O)](ClO4)2*1.5H2O (5), where bipy = 4,4′-bipyridine, dpe = trans-(4-pyridyl)-1,2-ethylene and TTF-CH = CH-py = 1-(2-tetrathiafulvalenyl)-2-(4-pyridyl)ethylene. Whereas complex 2 is built from discrete ionic particles (with rather long Cu-S contacts), compounds 1 and 3 contain 1D polymeric chains, in which structural units are bonded through Cu-O bonds or through bridging bipy molecule, respectively. Dinuclear complexes 4 and 5 are linked though π-stacking of dpe or TTF-CH = CH-py, respectively. All complexes are characterized by dominating ferromagnetic behavior with J values in the range from +9.92(8) cm−1 to +13.4(2) cm−1 for Hamiltonian H = -JS1S2. Magnetic properties of the compounds, containing stacks of aromatic molecules in crystal structures (4 and 5), correspond to ferromagnetic intradimer and antiferromagnetic intermolecular interactions (zJ′ = −0.158(3) and −0.290(2) cm−1, respectively). It was found that TTF-CH = CH-py ligand in [Cu2(LH)2(TTF-CH = CH-py)(H2O)]2+ could be electrochemically oxidized to cation-radical form in the solution

Thermal and near-infrared light induced spin crossover in a mononuclear iron( ii ) complex with a tetrathiafulvalene-fused dipyridophenazine ligand

A mononuclear Fe(II) complex involving a tetrathiafulvalene-based ligand exhibits thermal spin-crossover (around 143 K) with pronounced hysteresis behaviour (48 K). The chromophoric and π-extended ligand allows Near-Infrared (NIR) sensitization for the light-induced excited spin-state trapping (LIESST) with T(LIESST) = 90 K

Order in disorder:solution and solid-state studies of [(M2M5II)-M-III] wheels (M-III = Cr, Al; M-II = Ni, Zn)

A family of heterometallic Anderson-type ‘wheels’ of general formula [MIII2MII5(hmp)12](ClO4)4 (where MIII = Cr or Al and MII = Ni or Zn giving [Cr2Ni5] (1), [Cr2Zn5] (2), [Al2Ni5] (3) and [Al2Zn5] (4); hmpH = 2-pyridinemethanol) have been synthesised solvothermally. The metallic skeleton common to all structures describes a centred hexagon with the MIII sites disordered around the outer wheel. The structural disorder has been characterised via single crystal X-ray crystallography, 1–3D 1H and 13C solution-state NMR spectroscopy of the diamagnetic analogue (4), and solid-state 27Al MAS NMR spectroscopy of compounds (3) and (4). Alongside ESI mass spectrometry, these techniques show that structure is retained in solution, and that the disorder is present in both the solution and solid-state. Solid-state dc susceptibility and magnetisation measurements on (2) and (3) reveal the Cr–Cr and Ni–Ni exchange interactions to be JCr–Cr = −1 cm−1 and JNi–Ni,r = −5 cm−1, JNi–Ni,c = 10 cm−1. Fixing these values allows us to extract JCr–Ni,r = −1.2 cm−1, JCr–Ni,c = 2.6 cm−1 for (1), the exchange between adjacent Ni and Cr ions on the ring is antiferromagnetic and between Cr ions on the ring and the central Ni ion is ferromagnetic.EKB thanks the EPSRC for funding (EP/N01331X/1, EP/P025986/1). UGN acknowledges funding from the Villum Young Investigator (VKR022364) and the Danish Council for Independent Research – Natural Sciences (DFF – 7014-00198). ME thanks MINECO for funding (MAT2015-68204-R)Peer reviewe

Molecular assemblies based on tricyanomethanide units and copper(II) ions

cited By 36International audienceNew co-ordination polymers of formulae [Cu(tcm)2(tn)] (1) and [Cu(tcm)(tn)2](tcm) (2) (tcm-=tricyanomethanide and tn=1,3-diaminopropane) have been synthesised and characterised by X-ray crystallography and magnetic measurements. For compound 1, the Cu(II) ion presents an elongated and distorted CuN4N1N1 octahedron generated by one chelating tn ligand and by four μ 2-bridging tcm- ligands. The molecular arrangement of 1 can be described as a monodimensional chain of a ladder-like structure in which the Cu⋯Cu distance (7.5157(4) Å) through the tcm- ligand forming the sides is significantly shorter than the corresponding distance observed through that providing the rung (7.7455(4) Å). For compound 2, the Cu(II) ion presents a centrosymmetric elongated CuN 4N2 octahedron; the equatorial plane is generated by two chelating tn ligands and the two axial positions are filled by two weakly co-ordinated equivalent tcm- units acting as μ2- bridging ligands. This leads to a monodimensional polymer in which the intrachain Cu⋯Cu distance is 9.1062(2) Å. Magnetic measurements, performed in the temperature range 2-300 K for both compounds, show weak antiferromagnetic interactions for compound 1 while compound 2 obeys a Curie law. The difference between the magnetic behaviours can be explained from the larger intrachain Cu⋯Cu separation in 2 than in 1. © 2003 Elsevier Science B.V. All rights reserved

The cyanocarbanion (C[C(CN)2]3)2- as monodentate ligand: Synthesis, structure and magnetic properties of [Mn 2(bpym)3(tcpd)2(H2O)2] (tcpd2- = (C[C(CN)2]3)2- and bpym = 2,2′-bipyrimidine)

cited By 27International audienceOne-pot reaction between MnCl2•4H2O, K 2tcpd (tcpd2- = [C10N6]2- = (C[C(CN)2]3)2- = 2-dicyanomethylene-1,1,3,3- tetracyanopropanediide anion) and 2,2′-bipyrimidine (bpym = C 8H6N4) in aqueous solution yields the new compound [Mn2(bpym)3(tcpd)2(H 2O)2] (1). The molecular structure of 1 consists of a centrosymmetrical binuclear complex which includes unprecedented unidentate tcpd ligands with two bidentate and a bis-chelate bpym units. Examination of the intermolecular distances reveals that the dinuclear units are held together by hydrogen bonds involving coordinated water molecules and two nitrile groups of the tcpd ligand, giving rise to a 2D structure overall. Variable-temperature magnetic susceptibility data show the occurrence of slight antiferromagnetic coupling (J = -0.58 cm-1) between the Mn(II) ions through bridging bpym (the exchange Hamiltonian being defined as Ĥ=- 2JŜA·ŜB). © 2005 Elsevier B.V. All rights reserved

Preparation, X-ray crystal structures and properties of α-(BEDT-TTF)[Fe(phen)(NCS)[· 2CHCl and (BEDT-TTF)]Cr(isoq) (NCS)[ (phen = 1,10-phenanthroline; Isoq = isoquinoline)

This paper reports the preparation, X-ray crystal structure, conducting and magnetic properties of α-(BEDT-TTF)]Fe(phen) (NCS)[ (1) [BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene, phen = 1,10-phenanthroline] together with the crystal structure of (BEDT-TTF)]Cr (isoq)(NCS)[ (2) (isoq = isoquinoline) for which the physical properties have been reported previously. Compound 1 crystallizes in the triclinic space group P1 (no. 2), a = 12.1528(1), b = 16.8269(3), c = 27.0703(4) Å, α = 95.726(1), β = 95.834(1), γ = 108.080(1)°, Z = 4, R = 0.0610 for 9764 reflections with I > 2σ(I); 2 crystallizes in the monoclinic space group P2/c (no. 14), a =10.623(5), b = 14.656(8), c = 12.701(7) Å, β = 100.19(2)°, Z = 2, R = 0.0737 for 2747 reflections with I > 2σ(I). The magnetic and transport properties have shown that compound 1 is a paramagnetic semiconductor with σ = 2.2 × 10 Ω cm. © 2002 The Royal Society of Chemistry

[Cu(tn)]3[Cr(CN)6]2·3H2O: A unique two-dimensional Cu-Cr cyano-bridged ferromagnet (tn = 1,3-diaminopropane)

International audienceReaction of the two-coordinate 'assembling complex-ligand' [Cu(tn)]2+ with the building block [Cr(CN)6]3- leads to a unique two-dimensional Cu-Cr cyano-bridged ferromagnet with unusual μ3- and μ4-bridging [Cu(tn)]2+ units

Preparation, X-ray crystal structures and properties of α-(BEDT-TTF)[Fe(phen)(NCS)[· 2CHCl and (BEDT-TTF)]Cr(isoq) (NCS)[ (phen = 1,10-phenanthroline; Isoq = isoquinoline)

This paper reports the preparation, X-ray crystal structure, conducting and magnetic properties of α-(BEDT-TTF)]Fe(phen) (NCS)[ (1) [BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene, phen = 1,10-phenanthroline] together with the crystal structure of (BEDT-TTF)]Cr (isoq)(NCS)[ (2) (isoq = isoquinoline) for which the physical properties have been reported previously. Compound 1 crystallizes in the triclinic space group P1 (no. 2), a = 12.1528(1), b = 16.8269(3), c = 27.0703(4) Å, α = 95.726(1), β = 95.834(1), γ = 108.080(1)°, Z = 4, R = 0.0610 for 9764 reflections with I > 2σ(I); 2 crystallizes in the monoclinic space group P2/c (no. 14), a =10.623(5), b = 14.656(8), c = 12.701(7) Å, β = 100.19(2)°, Z = 2, R = 0.0737 for 2747 reflections with I > 2σ(I). The magnetic and transport properties have shown that compound 1 is a paramagnetic semiconductor with σ = 2.2 × 10 Ω cm. © 2002 The Royal Society of Chemistry

Charge transfer salt with substituted Lindquist polyoxometalate: Synthesis, crystal structure, and physical properties of α-(BEDT-TTF) 6(VW5O19·DMF·2H2O

International audienceA new charge transfer salt based on bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) and the vanadium substituted Lindquist anion [VW5O 19]3- was synthesized and characterized by X-ray and spectroscopic analysis. Monoclinic, C2, Fw = 3789.2, a = 41.5019(5), b = 11.2600(2), c = 12.7514(2) Å β = 101.877(5)°, Z = 2, R = 0.060, based on 12095 reflections with I > 2σ(I). The structure consists of alternating organic and inorganic layers. The inorganic layer is generated by [VW5O19]3- anions, dimethylformamide (DMF) and water molecules. The organic layer, which is generated by three different BEDT-TTF units, belongs to the α-type of packing and consists of trimerized chains parallel to the c direction. The compound is a semi-conductor with σ300K = 1.1 S·cm -1 and Ea = 0.1 eV. Polarized reflectance spectra of single crystals were measured over the spectral range from 650 to 25000 cm -1. FT-NIR Raman spectra of powdered crystals dispersed in KBr pellets were also recorded. Vibrational and electronic features are discussed