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Heterobimetallic

Paramagnetic complexes that possess magnetically switchable properties show promise in a number of applications. A significantly underdeveloped approach is the use of metallocages, whose magnetic properties can be modulated through host-guest chemistry. Here we show such an example that utilises a simple [Cu

Heterometallic Anderson wheels of formula [(V

A family of heterometallic Anderson-type 'wheels' of general formula [(M2M5II)-M-III(hmp)(12)](4+) (M-III = Cr or Al and M-II = Ni or Zn, Hhmp = 2-pyridinemethanol) has been extended to include M-III = Cr or Al and M-II = Co, Fe, Mn or Cu, affording five new species of formulae [Cr2Co5(hmp)(12)](ClO4)(4) (1), [Cr2Fe5(hmp)(12)](ClO4)(4) (2), [Cr2Mn5(hmp)(12)](ClO4)(4) (3), [Cr2Cu5(hmp)(12)](ClO4)(2)(NO3)(2) (4) and [Al2Co5(hmp)(12)](ClO4)(4) (5). As per previous family members, the metallic skeleton common to the cations of 1-5 describes a centred hexagon with the two M-III sites disordered around the outer wheel, with the exception of compound 4 where the Cu-II sites are localised. A structurally related, but enlarged planar disc possessing a [(M6MII)-M-III] hexagon capped on each edge by a Cu-II ion can be formed, but only when M-III = Al and M-II = Cu. In [(Al6Cu7II)-Cu-III(OH)(12)(hmp)(12)](ClO4)(6)(NO3)(2) (6) the Anderson moiety contains a central, symmetry-imposed octahedral Cu-II ion surrounded by a wheel of Al-III ions. Solid-state dc susceptibility and magnetisation measurements reveal the presence of competing exchange interactions in 1-5, and very weak antiferromagnetic exchange between the Cu-II ions in 6 which may be intra-and/or intermolecular in nature.

Three phenoxyimine Fe(iii)Cl complexes bearing electronically diverse -Cl, -H or

A large family of chromium(iii) dimers has been synthesised and magneto-structurally characterised using a combination of carboxylate and diethanolamine type ligands. The compounds have the general formula [Cr-2(R-1-deaH)(2)(O2CR2)Cl-2]Cl where R-1 = Me and R-2 = H (1), Me (2), CMe3 (3), Ph (4), 3,5-(Cl)(2)Ph (5), (Me)(5)Ph (6), R-1 = Et and R-2 = H (7), Ph (8). The compound [Cr-2(Me-deaH)(2)Cl-4] (9) was synthesised in order to study the effect of removing/adding the carboxylate bridge on the observed magnetic behaviour. Direct current (DC) magnetic susceptibility measurements showed ferromagnetic (FM) exchange interactions between the Cr(iii) centres in the carboxylate bridged family with coupling constants in the range +0.37

A family of heterometallic Anderson-type 'wheels' of general formula [MIII2MII5(hmp)12](ClO4)4 (where MIII = Cr or Al and MII = Ni or Zn giving [Cr2Ni5] (1), [Cr2Zn5] (2), [Al2Ni5] (3) and [Al2Zn5] (4); hmpH = 2-pyridinemethanol) have been synthesised solvothermally. The metallic skeleton common to all structures describes a centred hexagon with the MIII sites disordered around the outer wheel. The structural disorder has been characterised via single crystal X-ray crystallography, 1-3D 1H and 13C solution-state NMR spectroscopy of the diamagnetic analogue (4), and solid-state 27Al MAS NMR spectroscopy of compounds (3) and (4). Alongside ESI mass spectrometry, these techniques show that structure is retained in solution, and that the disorder is present in both the solution and solid-state. Solid-state dc susceptibility and magnetisation measurements on (2) and (3) reveal the Cr-Cr and Ni-Ni exchange interactions to be JCr-Cr = -1 cm-1 and JNi-Ni,r = -5 cm-1, JNi-Ni,c = 10 cm-1. Fixing these values allows us to extract JCr-Ni,r = -1.2 cm-1, JCr-Ni,c = 2.6 cm-1 for (1), the exchange between adjacent Ni and Cr ions on the ring is antiferromagnetic and between Cr ions on the ring and the central Ni ion is ferromagnetic.

Eight coordination compounds of formulae [Fe

While the phenolic oximes (R-saoH(2)) are well known for producing monometallic complexes of the type [MII(R-saoH)(2)] with Cu-II ions in near quantitative yield, their derivatisation opens the door to much more varied and interesting coordination chemistry. Here we show that combining the complimentary diethanolamine and phenolic oxime moieties into one organic framework (H4L1 and H4L2) allows for the preparation and isolation of an unusual family of [Cu-II](n) wheels, including saddle-shaped, single-stranded [Cu-8(II)] wheels of general formula [Cu-8(HL1)(4)(X)(4)] n[Y] (when n = 0, X = Cl-, NO3-, AcO-, N-3(-); when n = 2+X = (OAc)(2)/(2,2'-bpy)(2) and Y = [BF4](2)) and [Cu-8(HL2)(4)(X)(4)](X = Cl-, Br-), a rectangular [Cu-6(HL1)(4)] wheel, and a heterometallic [Cu4Na2(HL1)2(H2L1)(2)] hexagon. Magnetic studies show very strong antiferromagnetic exchange between neighbouring metal ions, leading to diamagnetic ground states in all cases. DFT studies reveal that the magnitude of the exchange constants are correlated to the Cu-N-O-Cu dihedral angles, which in turn are correlated to the planarity/puckering of the [Cu-II](n) rings.

The reactions of f-block silylamido N-heterocyclic carbene (NHC) complexes ([M(L)(N{SiMe3}2)2], M = Y, Ce, and U, L = bidentate alkoxy-tethered NHC ligand) with CO and CO2 have been studied and compared to each other, to those of selected [M(L)2 (N{SiMe3}2)] complexes, and to those of [M(N{SiMe3}2)3] to identify the effect of the labile NHC group on the small molecule activation chemistry. The small molecules COS and N2CPh2 have also been studied.