Harbi Tomah Al-Masri

Utilizing NMR and EPR spectroscopy to probe the role of copper in prion diseases

Copper is an essential nutrient for the normal development of the brain and nervous system, although the hallmark of several neurological diseases is a change in copper concentrations in the brain and central nervous system. Prion protein (PrP) is a copper‐binding, cell‐surface glycoprotein that exists in two alternatively folded conformations: a normal isoform (PrPC) and a disease‐associated isoform (PrPSc). Prion diseases are a group of lethal neurodegenerative disorders that develop as a result of conformational conversion of PrPC into PrPSc. The pathogenic mechanism that triggers this conformational transformation with the subsequent development of prion diseases remains unclear. It has, however, been shown repeatedly that copper plays a significant functional role in the conformational conversion of prion proteins. In this review, we focus on current research that seeks to clarify the conformational changes associated with prion diseases and the role of copper in this mechanism, with emphasis on the latest applications of NMR and EPR spectroscopy to probe the interactions of copper with prion proteins. Copyright

Synthesis and Characterization of New N-(Diphenylphosphino)-Naphthylamine Chalcogenides: X-Ray Structures of (1-NHC10H7)P(Se)Ph2 and Ph2P(S)OP(S)Ph2

Abstract The reaction of 1-naphthylamine with one equivalent of chlorodiphenylphosphine in the presence of triethylamine gave the (1-NHC10H7)PPh2 (1) ligand. Refluxing of 1 with elemental sulfur or grey selenium in toluene (1:1 molar ratio) afforded (1-NHC10H7)P(S)Ph2 (2) and (1-NHC10H7)P(Se)Ph2 (3), respectively. Moreover, the byproduct {Ph2P(S)}2O (4) was isolated from the reaction of 1 with elemental sulfur. Compounds 1–3 were identified and characterized by multinuclear (1H, 13C, 31P, 77Se) NMR spectroscopy, mass spectrometry, and elemental analysis. Crystal structure determinations of 3 and 4 were carried out. GRAPHICAL ABSTRACT

Synthesis and Molecular Structure of cis-Tetracarbonyl[N-(diphenylphosphino-kP)-naphthalen-1-yl-P,P-diphenylphosphinous amide-kP]chromium(0)

The reaction of N,N-bis(diphenylphosphanyl)naphthylamine C10H7-1-N(PPh2)2 with (C5H10NH)2Cr(CO)4 (1 : 1 molar ratio) in dichloromethane afforded cis-[Cr(CO)4C10H7-1-N(PPh2)2] (1). This complex was crystallized in the monoclinic space group P21/n. The structure was solved by direct methods and refined by full-matrix least squares techniques to an factor of 0.0313 for 6488 observed reflections. The Cr-metal is coordinated by four terminal CO molecules and a P,P′-bidentate N,N-bis(diphenylphosphanyl)naphthylamine ligand in a distorted octahedral array. The N-atom adopts a planar geometry with the two P-atoms and C-atom attached to it. The four-membered metallacycle ring P2CrN is nearly planar.

{[2-Methyl-2-(phenoxymethyl) propane-1,3-diyl]bis(oxy)}dibenzene

The title compound, C23H24O3, was obtained in a one-step (60% yield) synthesis from 1,1,1-tris(hydroxymethyl)ethane. It features a tripodal ligand capable of complexing metal centres. One of the three conformations involving the methyl group, the central C—C bond and the phenoxy substituents is antiperiplanar while the two others are synclinal [the corresponding C—C—C—O torsion angles are −174.6 (1), −53.2 (2) and −47.3 (2)°]. In the crystal, C—H⋯O interactions link the molecules into [010] chains.

{[2-Methyl-2-(phen-oxy-meth-yl)propane-1,3-di-yl]bis-(-oxy)}di-benzene.

The title compound, C23H24O3, was obtained in a one-step (60% yield) synthesis from 1,1,1-tris(hydroxymethyl)ethane. It features a tripodal ligand capable of complexing metal centres. One of the three conformations involving the methyl group, the central C—C bond and the phenoxy substituents is antiperiplanar while the two others are synclinal [the corresponding C—C—C—O torsion angles are −174.6 (1), −53.2 (2) and −47.3 (2)°]. In the crystal, C—H⋯O interactions link the molecules into [010] chains.

{[2-Methyl-2-(phenoxymethyl)propane-1,3-diyl]bis(oxy)}dibenzene

The title compound, C23H24O3, was obtained in a one-step (60% yield) synthesis from 1,1,1-tris(hydroxymethyl)ethane. It features a tripodal ligand capable of complexing metal centres. One of the three conformations involving the methyl group, the central C—C bond and the phenoxy substituents is antiperiplanar while the two others are synclinal [the corresponding C—C—C—O torsion angles are −174.6 (1), −53.2 (2) and −47.3 (2)°]. In the crystal, C—H⋯O interactions link the molecules into [010] chains.