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Graphical abstract Highlights • Hexanuclear heterometallic (FeIII 2 LnIII 4) (LnIII = GdIII; TbIII; DyIII and HoIII) complexes are described. • Magnetic studies reveal predominantly antiferromagnetic interactions among the paramagnetic metal centers. • Magnetic anisotropy is present in all the complexes except the GdIII analogue. • Mössbauer measurements confirm the non-magnetic ground state of the central FeIII 2 fragments) in these complexes. • ac Susceptibility measurements upto to 2 K do not reveal the presence of an out-of-phase signal. Abstract Hexanuclear heterometallic (FeIII 2 LnIII 4) (LnIII = GdIII; TbIII; DyIII and HoIII) complexes in a butterfly-shaped core are described. Two of the FeIII ions form part of the body and a pair of lanthanides are present in the wings. Detailed magnetic studies of all the complexes have been carried out which reveal predominantly antiferromagnetic interactions among the paramagnetic metal centers. The M vs H/T plots show the presence of magnetic anisotropy (except for the GdIII analogue) in these complexes. On the other hand, ac susceptibility measurements down to 2 K do not reveal the presence of an out-of-phase signal. Mössbauer measurements confirm the non-magnetic ground state of the central FeIII 2 fragments and absence of the transfer field from the DyIII to FeIII. [ABSTRACT FROM AUTHOR]

The Pd(II) bis(benzonitrile) complex [Pd(PhCN) 2 Cl 2 ] reacted with a mixture of 2-hydroxy-3-methoxybenzaldehyde, 1,3-diaminopropane, and triethylamine in acetonitrile to produce [Pd(L 1 )Cl] (HL 1 = ( E )-2-(((3-aminopropyl)imino)methyl)-6-methoxyphenol) ( 1 ), which contains an imine–amine-type macrocyclic ligand and a chloro ligand. Complex 1 was converted into a cyclohexane-like palladacycle, [Pd(NH 2 CH 2 CH 2 CH 2 NH 2 )Cl 2 ] ( 2 ), when heated in acetonitrile at 80 °C for 60 h. The palladium compartment complex [Pd(L 2 )] (H 2 L 2 = N , N ′-bis(3-methoxysalicylidenimino-1,3-diaminopropane) ( 3 ) was obtained from the free bis(imine) ligand (H 2 L 2 ) and [Pd(PhCN) 2 Cl 2 ] or Pd(OAc) 2 in methanol. All complexes were structurally characterized by X-ray diffraction. Complex 3 is the first structurally characterized palladium compartment complex, in which the compartment ligand has an inner N 2 O 2 and an outer O 2 O′ 2 compartments. The coordination geometry of the palladium metal in all complexes ( 1 – 3 ) can be best described as square-planar. [ABSTRACT FROM AUTHOR]

A series of neutral lanthanide alkoxide complexes stabilized by a new salen-type Schiff-base ligand were synthesized, and their catalytic behaviors for the ring-opening polymerization of lactide were explored. Amine elimination reactions of N -methyl- N ′, N ″-bis(3,5-di- tert -butylsalicylidene)-2,2′-diaminodiethylamine (LH 2 ) with Ln[N(SiMe 3 ) 2 ] 3 (Ln = Sm, Nd, La) in a 1:1 M ratio in THF, followed by reactions with 1 equiv of alcohols ( t BuOH, EtOH and CH 3 OCH 2 CH 2 OH), produced lanthanide alkoxide complexes LLn(O t Bu)(THF) (Ln = Sm ( 1 ), Nd ( 2 ), La ( 3 )), [LSm( μ -OEt)] 2 ( 4 ) and [LSm( μ -OCH 2 CH 2 OCH 3 )] 2 ( 5 ), respectively, whereas the same reaction with Yb[N(SiMe 3 ) 2 ] 3 gave an unexpected homoleptic complex L 2 Yb 2 ( μ -L) ( 6 ). X-ray structural determination showed that complexes 1 – 3 have a THF-solvated monomeric structure, whereas complexes 4 – 6 have an unsolvated dimeric structure. All lanthanide alkoxide complexes can efficiently initiate the ring-opening polymerization (ROP) of L -LA and rac -LA. The polymerization kinetics of L -LA initiated by complex 1 has been studied in detail and the first-order kinetic dependence on both l -lactide concentration and initiator concentration was found. Furthermore, all complexes showed moderate stereoselectivity for rac -LA polymerization to afford heterotactic-rich polylactides. [ABSTRACT FROM AUTHOR]

Substituted pyrazole containing Schiff-base ligand, 5-methyl-3-formylpyrazole-N-(2′-methylphenoxy)methyleneimine, (MPzOA), afforded three new Cd(II) complexes, [Cd(MP z OA)Cl 2 ] 2 .CH 3 OH ( I ), [Cd(MP z OA) 2 (H 2 O) 2 ](ClO 4 ) 2 ( II ) and [Cd(MP z OA)(H 2 O)(NO 3 ) 2 ] ( III ). In the reported complex species the coordination number and geometry of Cd(II) vary. In complex I and II, Cd(II) adopts six and in ( III ) it adopts eight coordination modes, with prismatic, octahedral and distorted dodecahedral geometry, respectively. All the complexes are characterized by IR, 1 H NMR, UV–Vis spectral parameters and X-ray analyses. The complexes have 1D, 2D and 3D supramolecular frameworks formed by non-covalent interactions, like hydrogen bonding, π … π stacking, C–H … π interactions. [ABSTRACT FROM AUTHOR]

Abstract: Reaction of equimolar proportion of trans-ReOCl3(PPh3)2 with HL, a 1:1 Schiff-base condensate of salicylaldehyde and allylamine, in chloroform gives rise to ReO(L)(PPh3)Cl2 1a in optimal yield. 1a has been characterized by C, H and N microanalyses, ESI-MS, FT-IR, UV–Vis spectra, molar conductivity measurements. The X-ray crystal structure of 1a reveals that it is an octahedral cis-Cl,Cl oxorhenium(V) complex. The rhenium center is in ‘NO2Cl2P’ coordination sphere. 1a crystallizes in the orthorhombic space group Pna21 with a =17.3541(11), b =10.2737(6), c =15.2113(10)Å, V =2712.0(3)Å3 and Z =4. The photophysical and electrochemical aspects of 1a have been studied. Electrochemical studies in dichloromethane show Re(V) to Re(VI) oxidation at 1.437V along with a reduction of Re(V) to Re(IV) at −0.705V versus Ag/AgCl. Excitation of 1a in chloroform at 460nm leads to a fluorescent emission at 525nm with a quantum yield (Ф) of 0.17. Geometry optimization of the cis-Cl,Cl complex 1a vis-à-vis its trans analogue, trans-Cl,Cl complex 1b, have been performed at the level of the density functional theory (DFT). It is revealed that 1b is more stable than 1a by 4kcal per mole of energy in gas phase. [Copyright &y& Elsevier]

Abstract: Reactions of the Schiff-base ligand, 2-hydroxyimino-3-(2-hydrazonopyridyl)-butane (LH) with copper(II) perchlorate hexahydrate and copper(II) nitrate trihydrate in 1:1molar proportion in methanol give rise respectively to Cu2L2(ClO4)2 (1a) and Cu2L2(NO3)2 (1b) in substantial yields. The complexes have been characterized by C, H and N microanalyses, copper estimation, ESI-MS, FT-IR, UV–Vis spectra, molar electric conductivity and room temperature magnetic susceptibility measurements. The X-ray crystal structures of both 1a and 1b have been determined. The structures reveal that both the complexes are oximato bridged dinuclear Cu(II) assemblies. The electrochemical studies of 1a and 1b show Cu(II) to Cu(III) oxidation in methanol. The thermal behavior of the nitrate analog, 1b, has also been forwarded to delve into the structure. Bond-Valence Sum (BVS) method of analyses was also performed to assign the oxidation state for each copper center both in 1a and 1b. [Copyright &y& Elsevier]

A dinuclear copper(II) complex with a newly synthesized tridentate Schiff-base ligand 2-[(2-hydroxy-ethylimino)-methyl]-4,6-diiodo-phenol (HL), of formula [Cu2L2Cl2 · C4H8O] (1), was prepared. Both the ligand and the complex were characterized by X-ray crystallography, confirming that the Schiff base is tridentate and its dinuclear copper(II) complex is five-coordinate from one nitrogen and two oxygens from L and two chlorides. The complex was assayed for antibacterial (Bacillus subtilis, Staphylococcus aureus, Streptococcus faecalis, Pseudomonas aeruginosa, Escherichia coli, and Enterobacter cloacae) activities by the MTT method. Complex 1 exhibited better antimicrobial activity than the ligand. [ABSTRACT FROM AUTHOR]

Abstract: A new azido derivative of a NNO donor tridentate Schiff-base copper(II) complex, [CuL(μ1,1-N3)] n (1) (HL=1-(N-ortho-hydroxyacetophenimine)-2-(N-ethyl)aminoethane), containing a single end-on μ1,1-azido bridged 1D infinite chain has been synthesized and characterized. X-ray single crystal structure analysis reveals that the complex [CuL(μ1,1-N3)] n (1) is a 1D chain in which neighboring Cu(II) chromophores are related by glide planes and linked by single azido bridges in the EO mode. No measurable magnetic interaction was evidenced in the complex [CuL(μ1,1-N3)] n (1) through variable temperature magnetic susceptibility measurements (10–300K). The complex was used as an active catalyst for the epoxidation of cyclooctene using tert-butyl-hydroperoxide as an oxidant. The catalytic activity of the complex has been compared in a series of solvents. The results show that in acetonitrile medium, the epoxide was produced in high yield with high selectivity. [Copyright &y& Elsevier]

Abstract: Four new heterometallic Cu(II)/Cr(III) complexes with N,N-dimethylethylenediamine (dmen) and its novel Schiff-base derivatives, N′-[(1Z)-3-amino-1,3-dimethylbutylidene]-N,N-dimethylethane-1,2-diamine (dmenac) and N′-((1Z)-3-{[2-(dimethylamino)ethyl]amino}-1,3-dimethylbutylidene)-N,N-dimethylethane-1,2-diamine (dmen2ac), have been easily prepared by self-assembly and characterized by spectroscopic methods and single crystal X-ray analysis. The structures of all the complexes are assisted by numerous hydrogen bonds that provide a web of interactions and mould the supramolecular architectures of the compounds. Variable-temperature (1.8–300K) magnetic susceptibility measurements reveal Curie-Weiss paramagnetic behavior of all the compounds, supported by EPR studies. [Copyright &y& Elsevier]

Abstract: The one-pot self-assembly reaction of copper powder, Reineckes salt, acetone and tris(2-aminoethyl)amine (tren) in dmso affords to obtain a heterometallic compound [Cu(trenac)][Cr(NCS)4(NH3)2](NCS)·6dmso with novel Schiff-base ligand N-(2-{[(1E)-3-amino-1,3-dimethylbutylidene]amino}ethyl)-N-(2-aminoethyl)ethane-1,2-diamine (trenac). The ligand trenac is generated by metal-directed condensation of tren, acetone and ammonia, formed during the synthetic procedure. X-ray structural investigations showed that the complex consists of [Cu(trenac)]2+ cations, anions of the Reineckes salt [Cr(NCS)4(NH3)2]−, uncoordinated thiocyanate groups and dmso molecules, which are held together by electrostatic forces and hydrogen-bonded interactions. The compound was characterized by EPR spectroscopic and magnetic susceptibility measurements. [Copyright &y& Elsevier]