Synthesis, supramolecular assemblies and luminescence of nickel(II) complexes based on a series of N-(2-pyridylmethyl) amino acid derivatives

A tetracobalt(II) cluster with a two vertex truncated dicubane topology endogenously supported by carboxylate-based (2-pyridyl)methylamine ligands: magneto-structural and DFT studies

A reaction between CoCl2 and L3-(CO2-)2 (2 : 1 stoichiometry) in CH3OH affords a discrete complex [CoII4-{L3-(CO2-)2}2(μ3-OCH3)2(CH3OH)2(H2O)2Cl2] (1) [L3-(CO2-)2 = 3-[N-{2-(pyridin-2-yl)methyl}amino]-bis(propionate)]. The structure of 1 reveals two terminal mononuclear CoII{L3-(CO2-)2}Cl units connected by a dimeric CoII2(μ3-OCH3)2(CH3OH)2(H2O) unit present in the centre through two methoxo (μ3-OCH3)- and two carboxylate (μ-1,1-OCO-) bridges affording a tetranuclear coordination cluster of Co(II) with a defective dicubane topology. In 1, Co1 (terminal) has distorted octahedral CoIIN2O3Cl and the central Co2 has CoIIO6 coordination. Such coordination arrangements afford the observed topology. Variable-temperature magnetic studies reveal anti-ferromagnetic coupling in 1. Three magnetic exchange interactions (one anti-ferromagnetic and two ferromagnetic: J1 = +3.3 cm-1 (Co⋯Co 3.176 Å; μ-1,1-OCO- and μ3-OCH3 bridges), J2 = -2.5 cm-1 (Co⋯Co 3.228 Å; μ-1-OCO- and μ3-OCH3 bridges) and J3 = +10.6 cm-1 (Co⋯Co 3.084 Å; two μ3-OCH3 bridges)) have been identified, with the inclusion of the orbital reduction parameter (α = Aκ = 1.38), spin-orbit coupling (λ = -158 cm-1) and axial distortion (energy gap Δ = -975 cm-1 between singlet and doublet levels), rationalized by density functional theory (DFT) calculations.

Dimeric Mn(ii), Co(ii), Ni(ii) and Cu(ii) complexes of a common carboxylate-appended (2-pyridyl)alkylamine ligand: structure, magnetism and DFT study

Weak anti- (1) and ferro-magnetic (2–4) interactions are observed in [MII2(L3)2(S)2]2+ (Mn 1, Co 2, Ni 3) (S = MeOH) and Cu 4 (S = none).

Supramolecular Assemblies, Luminescence and Anion Exchange of Helical Pb(II) Complexes Based on Enantiomeric N-(2-pyridylmethyl) Alanine Ligands

Two pairs of PbII coordination polymers have been synthesised using pyridine-functionalised amino acid derivatives N-(2-pyridylmethyl)-L(D)-alanine hydrochlorides [(L-Hpala)Cl or (D-Hpala)Cl] and PbII salts. Their X-ray structures confirm their formulations as [Pb(L-pala) (NO3)]n, [Pb(D-pala)(NO3)]n, [Pb(L-pala)(Cl)]n and [Pb(D-pala)(Cl)]n. They show similar coordination environments of PbII cations with two kinds of five-membered chelating rings, which are further assembled into 1D helical chains through the bridging carboxylates from amino acids. Thermal and fluorescent properties of these complexes have also been investigated.

Structure-induced catalysis enhancement of Cu-amino catalysts for rapidly selective oxidation of sulfides in the presence of H2O2

A Cu-amino coordination polymer promotes rapid sulfoxidation of benzyl phenyl sulfide toward the sulfoxide with high conversion and selectivity.

3d transition metal complexes with a julolidine–quinoline based ligand: structures, spectroscopy and optical properties

Five new complexes of a julolidine–quinoline based ligand with 3d transition metals have been synthesised and structurally characterised.