Against the Norm: Non Irving-Williams Transmetalation in Transition Metal Dimers.

We report the synthesis and characterization of three dinuclear 3d3d' complexes, CuCu ([Cu2IIL(NO3)2]), MnMn ([Mn2IIL(MeOH)2(NO3)2]), and CuMn ([CuIIMnIIL(NO3)2]), that utilize the ligand, H2L (6,6'-dimethoxy-2,2'-[(1,3-propylene)dioxybis(nitrilomethylidyne)]diphenol). The relative stabilities of these complexes were investigated using experimental and computational techniques, revealing a non-Irving-Williams transmetalation, whereby a MnII ion can displace a CuII ion from its binding pocket in CuCu to yield the more stable CuMn complex. Magnetic characterization of the reported complexes revealed an unexpected ferromagnetic coupling between the two CuII ions of CuCu with J = +63.0 cm-1.

Structural trends in a series of bulky dialkylbiarylphosphane complexes of CuI.

CuI complexes containing the bulky dialkylbiarylphosphane 2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl (tBuXPhos, L) and an ancillary ligand (Cl-, Br-, I-, MeCN, ClO4- or SCN-) have been structurally characterized, namely, chlorido[2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl-κP]copper(I), [CuCl(C29H45P)], 1, bromido[2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl-κP]copper(I), [CuBr(C29H45P)], 2, [2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl-κP]iodidocopper(I), [CuI(C29H45P)], 3, (acetonitrile-κN)[2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl-κP]copper(I) hexafluoridophosphate, [Cu(CH3CN)(C29H45P)]PF6, 4, [2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl-κP](perchlorato-κO)copper(I), [Cu(ClO4)(C29H45P)], 5, and di-µ-thiocyanato-κ2S:N;κ2N:S-bis{[2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl-κP]copper(I)}, [Cu2(NCS)2(C29H45P)2], 6. Iodide complex 3 shows significant CuI-arene interactions, in contrast to its chloride 1 and bromide 2 counterparts, which is attributed to the weaker interaction between the iodide ion and the CuI centre. When replacing iodide with an acetonitrile (in 4) or perchlorate (in 5) ligand, the reduced interaction between the CuI atom and the ancillary ligand results in stronger CuI-arene interactions. No CuI-arene interactions are observed in dimer 6, due to the tricoordinated CuI centre having sufficient electron density from the coordinated ligands.

The structural manipulation of a series of Ni4 defective dicubanes: Synthesis, X-ray Structures, Magnetic and Computational analyses.

We report the synthesis and characterization of four new tetranuclear Ni(ii) complexes, C1-C4, all of which exhibit defective dicubane cores. C1-C4 are derived from the same salicylaldoxime derived ligand, H2L1. Complexes C1 and C4 have isostructural cores, differing in structure only by solvate molecules. Magnetic and computational analyses have revealed that complexes C1, C2, and C4 exhibit competing ferro- and antiferromagnetic interactions, however the different solvated species in C1 and C4 leads to notably different magnitudes in their magnetic coupling constants. Theoretical magneto-structural studies show that the pairwise magnetic exchange interaction is highly dependent on the Ni-X-Ni angle, as revealed by orbital overlap calculations.

New salicylaldoximato-borate ligands resulting from anion hydrolysis and their respective copper and iron complexes.

Anion hydrolysis reactions between salicylaldoximato ligands (L'-L''') and copper and iron BF4- metal salts, have resulted in the formation of new salicylaldoximato borate containing transition metal complexes: [Fe2(L' + 2H)2](BF4)2(MeOH)4 (C1), [Fe3(L'' + 4H)(OH)2(Py)2](BF4)2(H2O)2(Py)2 (C2), and [Cu2(L''' + H)2Cl2] (C3). Each of the complexes have been structurally characterised, revealing the indirect role boron plays in the formation of these complexes. For complexes C1 and C2, Mössbauer spectroscopy confirmed the existence of Fe(iii) oxidation states. SQUID magnetometry measurements were performed on complexes C2 and C3, revealing the presence of two competing exchange pathways between the three Fe(iii) centres in C2, with antiferromagnetic exchange dominating. For C3 weak antiferromagnetic exchange dominated between the two Cu(ii) centres.