Enantiopure bis[{(R or S)-N-1-(Ar)ethyl-2-oxo-1-naphthaldiminato-κ(2)N,O}]nickel(ii) complexes {Ar = C6H5 ( or ), p-OMeC6H4 ( or ), and p-BrC6H4 ( or )} are synthesized from the reactions between (R or S)-N-1-(Ar)ethyl-2-oxo-1-naphthaldimine and nickel(ii) acetate. Circular-dichroism spectra and their density-functional theoretical simulation reveal the expected mirror image relationship between the enantiomeric pairs / and / in solution. CD spectra are dominated by the metal-centered Λ- or Δ-chirality of non-planar four-coordinated nickel, this latter being in turn dictated by the ligand chirality. Single crystal structure determination for and shows that there are two symmetry-independent molecules (A and B) in each asymmetric unit that give a Z' = 2 structure. Two asymmetric and chiral bidentate N^O-chelate Schiff base ligands coordinate to the nickel atom in a distorted square planar N2O2-coordination sphere. The conformational difference between the symmetry-independent molecules arises from the "up-or-down" folding of the naphthaldiminato ligand with respect to the coordination plane, which creates right- (P) or left-handed (M) helical conformations. Overall, the combination of ligand chirality, chirality at the metal and ligand folding gives rise to discrete metal helicates of preferred helicity in a selective way. Cyclic voltammograms (CV) show an oxidation wave at ca. 1.30 V for the [Ni(L)2]/[Ni(L)2](+) couple, and a reduction wave at ca. -0.35 V for the [Ni(L)2]/[Ni(L)2](-) couple in acetonitrile.

Enantiopure dinuclear μ‐aqua‐tetrakis[(R or S)‐N‐1‐(Ar)ethylsalicylaldiminato]di‐Λ‐ or ‐Δ‐nickel(II) [Ar = C6H5 (R‐1/S‐1), p‐MeOC6H4 (R‐2/S‐2), p‐ClC6H4 (R‐3/S‐3), p‐BrC6H4 (R‐4)] complexes have been synthesized from the reaction between (R or S)‐N‐1‐(Ar)ethylsalicylaldimine and nickel(II) acetate. Their CD spectra demonstrate chirality transfer from the ligands to the metal ions and a mirror‐image relationship for the enantiomeric pair R‐3/S‐3 in thf. DSC analyses show that the complexes exhibit an irreversible dissociation to the mononuclear species, which in turn undergo decomposition. The 1H NMR spectra reveal the presence of four salicylaldiminates, one aqua ligand, and two molecules of methanol in each dinuclear complex. They also confirm the existence of a dinuclear‐bridged aqua bis‐octahedral NiII complex in solution. The IR spectra in CH2Cl2 show a very strong band at around 2306 cm–1 due to the νO–H of the bridged aqua ligand. The X‐ray structures of R‐2, S‐2, R‐3, and S‐3 confirm the formation of dinuclear compounds comprising two nickel ions, four salicylaldiminates, and one aqua ligand with two molecules of methanol (or water in S‐2). Each nickel ion is surrounded by two N,O‐chelating salicylaldiminates, a bridging salicyl‐O atom from the neighboring nickel ion, and a bridging aqua ligand in a distorted octahedral polyhedron. Analyses of the absolute structures reveal a diastereomeric induction of the R or S ligand giving a Λ or Δ configuration at the nickel atoms in R‐2/3 or S‐2/3 that is independent of the ligand substituents.

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Weak supramolecular interactions can be decisive!

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Niemann Pick Disease (NPD) is a rare autosomal recessive lysosomal storage disease characterized by lysosomal lipid storage. The disease is caused by deficiency of enzyme, acid sphingomyelinase (ASM) which leads to accumulation of sphingomyelin & other lipids in reticuloendothelial cells of various organs like liver, spleen, bone marrow, lymph node, brain, nerves and kidney. Four types of the disease have been identified i.e. A, B, C and D. We report a case of Niemann Pick Disease type C. The patient was a 2.5 years female child who presented with developmental regression, recurrent seizures, failure to thrive and hepatospleenomegaly. Bone marrow (BM) aspiration was performed which showed hypercelluler marrow with few fat laden macrophage resembling foam cell that are characteristics of this disease. BSMMU J 2022; 15(2): 141-144

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