Heterometallic lanthanide-centred [NiII6LnIII] rings

A [NiII6DyIII] heptanuclear complex featuring a rare six-membered {NiII6} metal ring surrounding the central Dy(III) ion is reported. Magnetic studies reveal single-molecule magnet behaviour for the complex under zero external dc field, while replacing the DyIII ion with ΥIII or GdIII ions allows for a comprehensive understanding of the magnetic behaviour

Two unique star-like [MnIVMnIII2LnIII] clusters: magnetic relaxation phenomena

Synthesis and magnetic properties of two tetrametallic star-like [MnIVMnIII2Ln] (Ln: Gd, Dy) clusters.</p

A family of polynuclear cobalt complexes upon employment of an indeno-quinoxaline based oxime ligand

The reaction of Co(OAc)2·4H2O with LH (LH = 11H-indeno[1,2-b]quinoxalin-11-one oxime) in MeOH in the presence of NEt3 forms the complex [CoIII2CoIIO(OAc)3L3]·0.5MeOH·0.2H2O (1·0.5MeOH·0.2H2O), while repeating the reaction under solvothermal conditions yielded the heptanuclear cluster [CoII7L9 (OH)2(OAc)2.7(MeO)0.3(H2O)]·4.6MeOH·3.3H2O (2·4.6MeOH·3.3H2O). Changing the starting metal salt to Co(ClO4)2·6H2O and upon the reaction with LH in the presence of NEt3 under high temperature and pressure, we managed to isolate the decanuclear cluster [CoII10L14(OH)3.6(MeO)0.4](ClO4)2·8.5MeOH·5.75H2O (3·8.5MeOH·5.75H2O), while under normal bench conditions and upon employment of pivalates in the reaction mixture complex [CoII4L4(piv)4(MeOH)2]·MeOH·H2O (4·MeOH·H2O) was formed. Furthermore, the reaction of Co(ClO4)2·6H2O with LH and aibH (2-amino-isobutyric acid) in the presence of NEt3 in MeOH gave the mononuclear complex [CoIIIL(aib)2]·3H2O (5·3H2O), while upon increasing the metal–ligand ratio cluster [CoIII2CoIIL4(aib)2(OH)2]·7.9MeOH (6·7.9MeOH) was isolated. Finally, repeating the reaction that yielded the mononuclear complex 5·3H2O under solvothermal conditions, gave the octanuclear cluster [CoII8L10(aib)2(MeO)2](ClO4)2·6.8MeOH·7H2O (7·6.8MeOH·7H2O). Variable temperature dc magnetic susceptibility studies for complexes 2, 3, 4 and 7, reveal that all clusters display dominant antiferromagnetic interactions leading to small or diamagnetic ground-states,

Constructing CrIII-centered heterometallic complexes: [NiII6CrIII] and [CoII6CrIII] wheels

The solvothermal reaction between Cr(acac)3, MCl2.6H2O (M= Ni, Co) and 2-hydroxy-4-methyl-6-phenyl-pyridine-3-amidoxime (H2L), under basic conditions, led to the synthesis of the heterometallic heptanuclear clusters [MII6Cr(HLzw)6(HL)6].3Cl (M= Ni, 1; Co, 2), with the nickel analogue displaying an S= 9/2 spin ground-state

A Ferromagnetically Coupled, Bell-Shaped [Ni4Gd5] Cage

Reaction between NiCl2·6H2O, 2-hydroxy-4-methyl-6-phenyl-pyridine-3-amidoxime (H2L), benzoic acid, and M(NO3)3·6H2O (M = Gd, Y) in MeCN under basic conditions yields the complexes [NiII4GdIII5(PhCOO)10(HL)4(HLzw)4(OH)2(NO3)2]Cl·13.6MeCN·H2O (1·13.6MeCN·H2O) and [NiII4YIII5(PhCOO)10(HL)4(HLzw)4(OH)2(NO3)1.5(H2O)0.5]0.5Cl(NO3)·3H2O (2·3H2O). Both clusters display similar structures, consisting of a bell-shaped {NiII4MIII5} unit, in which a linear "zigzag" {Ni4} subunit bisects the central {MIII5} "ring". Direct (dc) and alternating current (ac) magnetic susceptibility measurements carried out in the 2-300 K temperature range for complexes 1 and 2 revealed ferromagnetic intermolecular interactions, while heat-capacity measurements for the Gd analogue suggest that complex 1 lowers its temperature from T = 9.6 K down to 2.3 K by adiabatically demagnetizing from Bi = 7 T to Bf = 0.E.K.B. thanks the EPSRC for funding grants EP/N01331X/1 and EP/P025986/1.Peer reviewe

(E)-4-{2-[(2-Hy­droxy­naphthalen-1-yl)methyl­idene]hydrazinecarbon­yl}pyridinium nitrate

The title compound, C17H14N3O2 +·NO3 −, is an aroylhydrazone-based material consisting of a 4-(hydrazinecarbon­yl)pyridinium cation and a nitrate anion. In the cation, the dihedral angle between the benzene ring and the naphthalene ring system is 2.20 (7)°. In the cation, the configuration about the C=N bond is E. There is an intra­molecular O—H⋯N hydrogen bond in the cation, and the supra­molecular structure is stabilized by inter­molecular N—H⋯O hydrogen bonds and weak C—H⋯O contacts between the cation and the nitrate anion

challenges for biomimetic water oxidation

Herein, we report the synthesis, characterization, crystal structure, density functional theory calculations, and water-oxidizing activity of a pivalate Mn–Ca cluster. All of the manganese atoms in the cluster are Mn(IV) ions and have a distorted MnO6 octahedral geometry. Three Mn(IV) ions together with a Ca(II) ion and four-oxido groups form a cubic Mn3CaO4 unit which is similar to the Mn3CaO4 cluster in the water-oxidizing complex of Photosystem II. Using scanning electron microscopy, transmission electron microscopy, energy dispersive spectrometry, extended X-ray absorption spectroscopy, chronoamperometry, and electrochemical methods, a conversion into nano-sized Mn-oxide is observed for the cluster in the water-oxidation reaction

A [Cr2Ni] coordination polymer:slow relaxation of magnetization in quasi-one-dimensional ferromagnetic chains

The reaction of [Cr3IIIO(OAc)6(H2O)3]NO3·AcOH with 2-hydroxynaphthaldehyde, 2-amino-isobutyric acid and NiCl2·6H2O in MeOH, under basic and solvothermal conditions, led to the formation of the quasi-1D coordination polymer {[CrIII2NiII(L)4(MeOH)2]}n (where L = the dianion of the Schiff base between 2-hydroxynaphthaldehyde and 2-amino-isobutyric acid), which behaves as a ferromagnetic chain, displaying slow relaxation of magnetization.ME thanks DIPC for the support of his stay at San Sebastián and MINECO for funding (MAT2015-68204-R). JML thanks the Excellence Unit ‘‘Maria de Maeztu’’ [MDM-2015-0538].Peer reviewe

A [Ce21] Keplerate

The solvothermal reaction between Ce(NO3)3·6H2O, 2-amino-isobutyric acid, 2-hydroxy-1-naphthaldehyde and 2-amino-2-methyl-1,3-propanediol in MeOH, in the presence of base, leads to the formation of a unique [CeIV13Ce III8] keplerate cage