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Plexiform neurofibromas are essentially pathognomonic for neurofibromatosis type 1 (NF1), occurring when there is diffuse involvement along a nerve segment and its branches. Transformation into a malignant peripheral nerve sheath tumour (MPNST) is a major cause of mortality in NF1 patients. These tumours are highly aggressive and particularly difficult to diagnose in NF1 patients due to the clinical overlap between benign and malignant lesions. We present a case of a plexiform neurofibroma and discuss the typical imaging characteristics on ultrasound, CT, and MRI, including the target sign and continuity with the parent nerve. Certain imaging features should raise suspicion for malignancy however, these modalities may not always reliably differentiate between benign and malignant lesions. Recent studies show a very high negative predictive value for FDG-PET making it quite useful in excluding malignancy. In positive scans, PET/CT aids in guiding biopsy to the most metabolically active area of the tumour.

Molecular lanthanide (Ln) complexes are promising candidates for the development of next-generation quantum technologies. High-symmetry structures incorporating integer spin Ln ions can give rise to well-isolated crystal field quasi-doublet ground states, i.e., quantum two-level systems that may serve as the basis for magnetic qubits. Recent work has shown that symmetry lowering of the coordination environment around the Ln ion can produce an avoided crossing or clock transition within the ground doublet, leading to significantly enhanced coherence. Here, we employ single-crystal high-frequency electron paramagnetic resonance spectroscopy and high-level ab initio calculations to carry out a detailed investigation of the nine-coordinate complexes, [Ho III L 1 L 2 ], where L 1 = 1,4,7,10-tetrakis(2-pyridylmethyl)-1,4,7,10-tetraaza-cyclododecane and L 2 = F - ( 1 ) or [MeCN] 0 ( 2 ). The pseudo-4-fold symmetry imposed by the neutral organic ligand scaffold (L 1 ) and the apical anionic fluoride ion generates a strong axial anisotropy with an m J = ±8 ground-state quasi-doublet in 1 , where m J denotes the projection of the J = 8 spin-orbital moment onto the ∼ C 4 axis. Meanwhile, off-diagonal crystal field interactions give rise to a giant 116.4 ± 1.0 GHz clock transition within this doublet. We then demonstrate targeted crystal field engineering of the clock transition by replacing F - with neutral MeCN ( 2 ), resulting in an increase in the clock transition frequency by a factor of 2.2. The experimental results are in broad agreement with quantum chemical calculations. This tunability is highly desirable because decoherence caused by second-order sensitivity to magnetic noise scales inversely with the clock transition frequency.

Two new paths for coordination driven self-assembly reactions under the binding support of 2-((1-hydroxy-2-methylpropan-2-ylimino)methyl)-6-methoxyphenol (H 2 L) have been discovered from the reactions of Cu(ClO 4 ) 2 ·6H 2 O, NEt 3 and GdCl 3 /DyCl 3 ·6H 2 O in MeOH/CHCl 3 (2 : 1) medium. A similar synthetic protocol is useful to provide two different types of self-aggregated molecular clusters [Cu 6 Gd 3 (L) 3 (HL) 3 (μ 3 -Cl) 3 (μ 3 -OH) 6 (OH) 2 ]ClO 4 ·4H 2 O (1) and [Cu 5 Dy 2 (L) 2 (HL) 2 (μ-Cl) 2 (μ 3 -OH) 4 (ClO 4 ) 2 (H 2 O) 6 ](ClO 4 ) 2 ·2NHEt 3 Cl·21H 2 O (2). The adopted reaction procedure established the importance of the HO - and Cl - ions in the mineral-like growth of the complexes, derived from solvents and metal ion salts. In the case of complex 1, one Gd III center has been trapped at the central position of the core upheld by six μ 3 -OH and three μ 3 -Cl groups, whereas for complex 2 one Cu II center was trapped using four μ 3 -hydroxo and two μ-chlorido groups. The magnetothermal behavior of 1 has been examined for a magnetocaloric effect of -Δ S m = 11.3 J kg -1 K -1 at 2 K for Δ H = 7 T, whereas the magnetic susceptibility measurements of 2 showed slow magnetic relaxation with U eff = 15.8 K and τ 0 = 9.8 × 10 -7 s in zero external dc field. Cancer cell growth inhibition studies proved the potential of both the complexes with interestingly high activity for the Cu 6 Gd 3 complex against human lung cancer cells. Both complexes 1 and 2 also exhibited DNA and human serum albumin (HSA) binding abilities in relation to the involved binding sites and thermodynamics.

The multinucleating ligand 2,2'-(propane-1,3-diyldiimino)bis[2-(hydroxymethyl)-propane-1,3-diol] (bis-tris propane, H 6 L) is used in the design of a new family of 3d-4f complexes that display an unusual {LnCu 4 } four-blade propeller topology. We report the synthesis, structure and magnetic characterisation of [LnCu 4 (H 4 L) 4 ](Cl) 2 (ClO 4 )·6CH 3 OH, where Ln = Gd (1), Tb (2), Dy (3), La (4). Previously we have used CH 3 COO - and NO 3 - as co-ligands with bis-tris propane, but here the use of Cl - and ClO 4 - leads to coordination of four {Cu(H 4 L)} units around the central Ln ion. A magneto-structural analysis reveals that the geometrical arrangement of the Cu(II) centres defined by the H 4 L 2- ligands controls the magnetic communication between the different metal centres. DFT calculations performed on the isotropic (Gd) and diamagnetic (La) systems 1 and 4 help to unravel the intriguing exchange interactions.

Use of the 1,3,5-tri(2-hydroxyethyl)-1,3,5-triazacyclohexane ligand, LH 3 , in manganese chemistry affords access to two structurally related {Mn 8 } clusters: a "closed" {Mn III 6 Mn II 2 } puckered square wheel of formula [Mn 8 L 2 (LH)O 3 (OH) 2 (MeO) 2 Br(imH)(H 2 O) 3 ](Br) 3 ( 1 ; imH = imidazole) and an "open" {Mn III 8 } rod of formula [Mn ΙΙΙ 8 L 2 O 4 (aibH) 2 (aib) 2 (MeO) 6 (MeOH) 2 ](NO 3 ) 2 ( 2 , aibH = 2-amino-isobutyric acid). In each case the triaza ligands, L/LH, direct the formation of {Mn 3 } triangles with their N atoms preferentially bonding to the Jahn-Teller axes of the Mn III ions. Subsequent self-assembly is dependent on the anion of the Mn salt and the identity of the organic coligand employed-the terminally bonded imidazole and the chelating/bridging amino acid. The {Mn 3 } triangles fold up on themselves in 1 , forming a wheel. However, the syn, syn-bridging carboxylates in 2 prevent this from happening, instead directing the formation of a linear rod. Magnetic susceptibility and magnetization measurements reveal competing ferro- and antiferromagnetic interactions in both complexes, the exchange being somewhat weaker in 1 due to the presence of Mn II ions., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

The recently reported compound [Dy III LF](CF 3 SO 3 ) 2 ·H 2 O (L = 1,4,7,10-tetrakis(2-pyridylmethyl)-1,4,7,10-tetraaza-cyclododecane) displays a strong axial magnetic anisotropy, due to the short axial Dy-F bond, and single-molecule magnet (SMM) behavior. Following our earlier [Dy III LF] 2+ work, herein we report the systematic structural and magnetic study of a family of [Ln III LF](CF 3 SO 3 ) 2 ·H 2 O compounds (Ln(III) = 1 -Ce, 2 -Pr, 3 -Nd, 4 -Eu, 5 -Tb, 6 -Ho, 7 -Er, 8 -Tm, and 9 -Yb). From this series, the Ce(III) and Nd(III) analogues show slow relaxation of the magnetization under an applied direct current magnetic field, which is modeled using a Raman process. Complete active space self-consistent field theoretical calculations are employed to understand the relaxation pathways in 1 -Ce and 3 -Nd and also reveal a large tunnel splitting for 5 -Tb. Additional computational studies on model compounds where we remove the axial F - ligand, or replace F - with I - , highlight the importance of the F - ligand in creating a strong axial crystal field for 1 -Ce and 3 -Nd and for promoting the SMM behavior. Importantly, this systematic study provides insight into the magnetic properties of these lighter lanthanide ions.

We present the magnetic anisotropy of two isostructural pentagonal-bipyramidal complexes, [Ln(H 2 O) 5 (HMPA) 2 ]I 3 ·2HMPA (HMPA = hexamethylphosphoramide, Ln = Dy, Ho). Using ac magnetic susceptibility measurements, we find magnetic relaxation barriers of 600 K and 270 K for the Dy- and Ho-compounds, respectively. This difference is supported by polarized neutron diffraction (PND) measured at 5 K and 1 T which provides the first experimental evidence that the transverse elements in the magnetic anisotropy of the Ho-analogue are significant, whereas the Dy-analogue has a near-axial magnetic anisotropy with vanishing transverse contributions. The coordination geometries of the two complexes are highly similar, and we attribute the loss of strong magnetic axiality as expressed in the atomic susceptibility tensors from PND, as well as the smaller relaxation barrier in the Ho-complex compared to the Dy-complex, to the less favorable interaction of the pentagonal bipyramidal crystal field with the characteristics of the Ho(III) 4f-charge distribution.

Two new families of cobalt(ii/iii)-lanthanide(iii) coordination aggregates have been reported: tetranuclear [LnCoL 2 (N-BuDEA) 2 (O 2 CCMe 3 ) 4 (H 2 O) 2 ]·(MeOH) n ·(H 2 O) m (Ln = Gd, 1; Tb, 2; Dy, 3; n = 2, m = 10 for 1 and 2; n = 6, m = 2 for 3) and pentanuclear LnCo II CoL 2 (N-BuDEA) 2 (O 2 CCMe 3 ) 6 (MeOH) 2 (Ln = Dy, 4; Ho, 5) formed from the reaction of two aggregation assisting ligands H 2 L (o-vanillin oxime) and N-BuDEAH 2 (N-butyldiethanolamine). A change in preference from a lower to higher nuclearity structure was observed on going across the lanthanide series brought about by the variation in the size of the Ln III ions. An interesting observation was made for the varying sequence of addition of the ligands into the reaction medium paving the way to access both structural types for Ln = Dy. HRMS (+ve) of solutions gave further insight into the formation of the aggregates via different pathways. The tetranuclear complexes adopt a modified butterfly structure with a more complex bridging network while trapping of an extra Co II ion in the pentanuclear complexes destroys this arrangement putting the Co-Co-Co axis above the Ln-Ln axis. Direct current (dc) magnetic susceptibility measurements reveal weak antiferromagnetic coupling in 1. Complexes 2 and 5 display no slow magnetic relaxation, whereas complexes 3 and 4 display out-of-phase signals at low temperature in ac susceptibility measurements. All compounds were analyzed with DFT and CASSCF calculations and informations about the single-ion anisotropies and mutual 4f-4f/4f-3d magnetic interactions were derived.

Five new cobalt(ii/iii)-lanthanide(iii)-based coordination aggregates, [LnIII3CoII2CoIII2(L1)2(O2CCMe3)8(OH)4(OMe)2(H2O)4]·Ln(η1-O2CCMe3)2(η2-O2CCMe3)2(MeOH)2·2MeOH·2H2O (where Ln = Tb (1), Ho (3), and H2L1 = N-(2-hydroxyethyl)-salicylaldimine), TbIII3CoII3CoIII4(L1)4(O2CCMe3)9(OH)10(H2O) (4) and LnIII3CoII2CoIII5(L1)4(O2CCMe3)10(OH)10 (Ln = Dy (5), Ho (6)) have been synthesized and characterized, including structural analysis via single-crystal X-ray diffraction. The dysprosium analogue (2) of 1 and 3 was previously reported by us. The heptanuclear monocationic clusters in 1 and 3 were formed by placement of seven metal ions (4 Co and 3 Ln) in a vertex shared dicubane structure from the control of two Schiff base anions and crystallized in the presence of in situ generated and literature unknown counter anions Tb(η1-O2CCMe3)2(η2-O2CCMe3)2(MeOH)2- and Ho(η1-O2CCMe3)2(η2-O2CCMe3)2(MeOH)2-. Interesting solvent-induced cluster structure transformation was observed on dissolving the heptanuclear aggregates in MeCN for the formation of decanuclear clusters 4-6. These high nuclearity clusters consist of a vertex shared heptanuclear dicubane part and a curved trinuclear chain linking the two cubic halves. The dicubane unit differs from that of the heptanuclear precursors in the presence of CoII/III at the shared vertex as opposed to LnIII and the absence of OMe- bridges. HRMS (+ve) analysis shed light on the pathway of formation of these heptanuclear molecules, while at the same time revealing a different aggregation process for the decanuclear clusters.

The design and synthesis of a Schiff base H 2 L, (2-{[(2-hydroxy-3-methoxybenzyl)imino]methyl}phenol), bearing an ONOO donor set has been explored for its reactivity pattern with LnCl 3 ·6H 2 O (Ln = Gd III and Dy III ) and Ni(CH 3 CO 2 ) 2 ·4H 2 O in the presence of NEt 3 for molecular aggregation. Coordination driven spontaneous self-assembly reactions provide [Gd 2 Ni 6 L 4 (μ 3 -OH) 6 (μ-OH) 2 (CH 3 CO 2 ) 2 (μ-H 2 O) 2 (H 2 O) 3 (MeOH)]·8H 2 O (1) having a 'butterfly-shaped' core and [Dy 2 Ni 6 L 4 (μ 3 -OH) 4 (μ-Cl) 2 Cl 4 (H 2 O) 2 (MeOH) 2 ]·2MeOH·4H 2 O (2) with a 'candy-shaped' core. Fusion of six partial cubane units led to a mineral-like core in 1, developed around the central Ni 2 (OH) 2 moiety, whereas in the case of 2, four such partial cubanes collapsed on Dy 2 (OH) 2 . Direct-current (dc) magnetic susceptibility measurements revealed that predominant ferromagnetic interactions lead to a high-spin S = 13 ground state for 1. Complex 2 exhibits slow relaxation of magnetization under an applied small dc field with an energy barrier to reorientation of the magnetization, U eff = 19.3 K. The static and dynamic magnetic data are analysed and corroborated by density functional theory (DFT) and detailed CASSCF based calculations.

Reaction of Ni(OTf) 2 with the bisbidentate quaterpyridine ligand L results in the self-assembly of a tetrahedral, paramagnetic cage [Ni II 4 L 6 ] 8+ ), we have been able to prepare a series of host-guest complexes that feature an encapsulated paramagnetic tetrahalometallate ion inside this paramagnetic host giving [M II 4 L 6 , where M 7 ( 1 ), we have been able to prepare a series of host-guest complexes that feature an encapsulated paramagnetic tetrahalometallate ion inside this paramagnetic host giving [M II X 4 ⊂Ni II 4 L 6 ](OTf) 6 , where M II X 4 2- ) or [M 4 2- ( 2 ), CoCl 4 , where M 2- ( 5 ), CoBr 4 2- ( 6 ), NiCl 4 2- ( 7 ), and CuBr 4 2- ( 8 ) or [M III X 4 ⊂Ni II 4 L 6 ](OTf) 7 , where M III X 4 - = FeCl 4 - ( 3 ) and FeBr 4 - ( 4 ). Triflate-to-tetrahalometallate exchange occurs in solution and can also be accomplished through single-crystal-to-single-crystal transformations. Host-guest complexes 1-8 all crystallise as homochiral racemates in monoclinic space groups, wherein the four {NiN 6 } vertexes within a single Ni 4 L 6 unit possess the same Δ or Λ stereochemistry. Magnetic susceptibility and magnetisation data show that the magnetic exchange between metal ions in the host [Ni II 4 ] complex, and between the host and the MX 4 n - guest, are of comparable magnitude and antiferromagnetic in nature. Theoretically derived values for the magnetic exchange are in close agreement with experiment, revealing that large spin densities on the electronegative X-atoms of particular MX 4 n - guest molecules lead to stronger host-guest magnetic exchange interactions., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

We generate a new air-stable pseudo-D 5h Dy(iii) Single-Molecule Magnet (U eff = 1108 K, T B = 14 K) by combining a weak equatorial ligand field from a macrocyclic L N5 ligand with a strong axial ligand field. Based on our synthetic blueprint, we use ab initio calculations to show the vast scope for macrocyclic engineering of magnetic anisotropy.

The first trigonal bipyramidal Fe(ii) complex to display slow relaxation of magnetisation has been isolated, with this behaviour found to arise through a combination of a large magnetic anisotropy (D = -27.5 cm -1 ) and a pseudo-D 3h symmetry at the Fe(ii) centre, as investigated through ab initio and magnetic studies.

A new air-stable sulfur-ligated Dy(iii) single-ion magnet has been successfully isolated with Ueff = 638 K and hysteresis loops open up to 7 K. In silico studies show that the S co-ligands significantly boost the axiality and that Te- and Se-donors have the potential to further enhance the magnetic properties.

Understanding how the magnetic anisotropy in simple coordination complexes can be manipulated is instrumental to the development of single-molecule magnets (SMMs). Clear strategies can then be designed to control both the axial and transverse contributions to the magnetic anisotropy in such compounds, and allow them to reach their full potential. Here we show a strategy for boosting the magnetic anisotropy in a series of trigonal bipyramidal Mn(ii) complexes - [MnCl 3 (HDABCO)(DABCO)] (1), [MnCl 3 (MDABCO) 2 ]·[ClO 4 ] (2), and [MnCl 3 (H 2 O)(MDABCO)] (3). These have been successfully synthesised using the monodentate [DABCO] and [MDABCO] + ligands. Through static (DC) magnetic measurements and detailed theoretical investigation using ab initio methods, the magnetic anisotropy of each system has been studied. The calculations reveal that the rhombic zero-field splitting (ZFS) term (E) can be tuned as the symmetry around the Mn(ii) ion is changed. Furthermore, an in silico investigation reveals a strategy to increase the axial ZFS parameter (D) of trigonal bipyramidal Mn(ii) by an order of magnitude.

The chelating ligand 1,3-bis(tris(hydroxymethyl)methylamino)propane (H 6 L) has been used to synthesize a family of octanuclear heterometallic complexes with the formula (NMe 4 ) 3 [Mn 4 Ln 4 (H 2 L) 3 (H 3 L)(NO 3 ) 12 ] (Ln = La ( 1 ), Ce ( 2 ), Pr ( 3 ), Nd ( 4 )). Encapsulation by the ligand causes the Mn(III) centers to lie in an unusually distorted (∼ C 2 v ) environment, which is shown by density functional theory and complete active space self-consistent field calculations to impact on the magnetic anisotropy of the Mn(III) ion. The theoretical study also supports the experimental observation of a ferromagnetic superexchange interaction between the Mn(III) ions in 1 , despite the ions being separated by the diamagnetic La(III) ion. The optical properties of the compounds show that the distortion of the Mn(III) ions leads to three broad absorption bands originating from the transition metal ion, while the Nd(III) containing complex also displays some weak sharp features arising from the lanthanide f-f transitions.

Following a novel synthetic strategy where the strong uniaxial ligand field generated by the Ph 3 SiO - (Ph 3 SiO - =anion of triphenylsilanol) and the 2,4-di- t Bu-PhO - (2,4-di- t Bu-PhO - =anion of 2,4-di-tertbutylphenol) ligands combined with the weak equatorial field of the ligand L N6 , leads to [Dy III (L N6 )(2,4-di- t Bu-PhO) 2 ](PF 6 ) (1), [Dy III (L N6 )(Ph 3 SiO) 2 ](PF 6 ) (2) and [Dy III (L N6 )(Ph 3 SiO) 2 ](BPh 4 ) (3) hexagonal bipyramidal dysprosium(III) single-molecule magnets (SMMs) with high anisotropy barriers of U eff =973 K for 1, U eff =1080 K for 2 and U eff =1124 K for 3 under zero applied dc field. Ab initio calculations predict that the dominant magnetization reversal barrier of these complexes expands up to the 3rd Kramers doublet, thus revealing for the first time the exceptional uniaxial magnetic anisotropy that even the six equatorial donor atoms fail to negate, opening up the possibility to other higher-order symmetry SMMs., (© 2019 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.)

In molecular magnetism and single-ion magnets in particular, the observation of slow relaxation of the magnetization is intimately linked to the coordination environment of the metal center. Such systems typically have blocking temperatures well below that of liquid nitrogen, and therefore detailed magnetic characterization is usually carried out at very low temperatures. Despite this, there has been little advantage taken of ultralow temperature single-crystal X-ray diffraction techniques that could provide a full understanding of the crystal structure in the same temperature regime where slow magnetic relaxation occurs. Here, we present a systematic variable temperature single crystal X-ray diffraction study of [Co II (NO 3 ) 3 (H 2 O)(HDABCO)] ( 1 ) {DABCO = 1,4-diazabicyclo[2.2.2]octane} conducted between 295 to 4 K. A reversible and robust disorder-to-order, single-crystal to single-crystal phase transition was identified, which accompanied a switching of the coordination geometry around the central Co(II) from 5- to 7-coordinate below 140 K. The magnetic properties were investigated, revealing slow relaxation of the magnetization arising from a large easy-plane magnetic anisotropy (+ D ) in the Co(II) pentagonal bipyramidal environment observed at low temperatures. This study highlights the importance of conducting thorough low temperature crystallographic studies, particularly where magnetic characterization is carried out at such low temperatures.

A new nine-coordinate, air-stable Dy(iii) single-ion magnet has been successfully isolated. Our in silico studies demonstrate that through carefully modulating the ligand electronics, the axiality can be boosted to generate Ucal barriers of over 600 K.

The magnetic properties of 3d monometallic complexes can be tuned through geometric control, owing to their synthetic accessibility and relative structural simplicity. Monodentate ligands offer great potential for fine-tuning the coordination environment to engineer both the axial and rhombic zero-field splitting (ZFS) parameters. In [CoCl 3 (DABCO)(HDABCO)] ( 1 ), the trigonal bipyramidal Co(ii) centre has two bulky axial ligands and three equatorial chloride ligands. An in-depth experimental and theoretical study of 1 reveals a large easy-plane magnetic anisotropy (+ve D ) with a negligible rhombic zero-field splitting ( E ) due to the strict axial symmetry imposed by the C 3 symmetric ligand and trigonal space group. The large easy-plane magnetic anisotropy ( D = +44.5 cm -1 ) is directly deduced using high-field EPR and frequency-domain magnetic resonance (FDMR) studies. Ab initio calculations reveal a large positive contribution to the D term arising from ground state/excited state mixing of the 4 E'' states at ∼4085 cm -1 and a minor contribution from the spin-flip transition as well. The nature of the slow relaxation in 1 is elucidated through analysis of the rates of relaxation of magnetisation, taking into account Raman and direct spin-lattice relaxation processes and Quantum Tunnelling of the Magnetisation (QTM). The terms relating to the direct process and QTM were found based on the fit of the field-dependence of τ at 2 K. Subsequently, these were used as fixed parameters in the fit of the temperature-dependence of τ to obtain the Raman terms. This experimental-theoretical investigation provides further insight into the power of FDMR and ab initio methods for the thorough investigation of magnetic anisotropy. Thus, these results contribute to design criteria for high magnetic anisotropy systems.

We report a new {CoII9} complex with an unprecedented structure and its solvated analogue, using microwave heating to tune the synthesis and improve the product selectivity.

The Schiff base ligand HL1 ({2,6-bis(allylimino)methyl}-4-methylphenol) having no coordinating donor arm has been examined for its reaction medium and ancillary bridge dependent reactivity for a hierarchical family of CuII complexes. The ligand showed a unique reactivity pattern toward CuII in solution. The bridging nature of in situ generated HO- ions in the absence and presence of externally added carboxylates (RCOO-; R = CF3, C6H5 and CH3) has been utilized to produce complexes {[Cu2(μ-L2)2(H2O)]2[Cu2(μ-L2)2(H2O)2](ClO4)6} (1) (HL2 = 3-{(allylimino)methyl}-2-hydroxy-5-methylbenzaldehyde), [Cu4(μ4-O)(μ-L1)2(μ1,3-O2CCF3)4] (2), [Cu4(μ4-O)(μ-L1)2(μ1,3-O2CC6H5)4]·H2O (3), and [Cu5(μ3-OH)2(μ-L1)2(μ1,3-OAc)2(OAc)2(H2O)4][Cu5(μ3-OH)2(μ-L1)2(μ1,3-OAc)2(OAc)3(H2O)](ClO4)3·2C2H5OH (4). The absence of carboxylate anions did not yield HO- ions in situ and triggered single ligand arm hydrolysis. The formation of tetra- and pentanuclear aggregates as well as ligand hydrolyzed dinuclear products has been rationalized to identify the possible roles of carboxylate anions in solution. Detailed characterization of the complexes in the solid state and in solution has been carried out using spectroscopic measurements, X-ray crystallography, variable temperature magnetic measurements and functional behavior. In MeOH solutions at 298 K, the complexes 1-4 showed catalytic oxidation of 3,5-di-tert-butyl catechol (3,5-DTBCH2) saturated with O2 from the air.

A systematic one-step one-pot multicomponent reaction of Co(ClO 4 ) 2 ·6H 2 O, H 3 L (2,6-bis((2-(2-hydroxyethylamino)ethylimino)methyl)-4-methylphenol), and readily available carboxylate salts (RCO 2 Na; R = CH 3 , C 2 H 5 ) resulted in the two structurally novel coordination aggregates [Co II Co III 4 L 2 (μ 1,3 -O 2 CCH 3 ) 2 (μ-OH) 2 ](ClO 4 ) 4 ·4H 2 O (1) and [Co II Co III 4 L 2 (μ 1,3 -O 2 CC 2 H 5 ) 2 (μ-OH)(μ-OMe)](ClO 4 ) 4 ·5H 2 O (2). At room temperature, reactions of H 3 L in MeOH with cobalt(II) perchlorate salts led to coassembly of initially formed ligand-bound {Co II 2 } fragments following aerial oxidation of metal centers and bridging by in situ generated hydroxido/alkoxido groups and added carboxylate anions. Available alkoxido arms of the initially formed {L(μ 1,3 -O 2 CCH 3 )(μ-OH/OMe)Co 2 } + fragments were utilized to trap a central Co II ion during the formation of [Co 5 ] aggregates. In the solid state, both complexes have been characterized by X-ray crystallography, variable-temperature magnetic measurements, and theoretical studies. Both 1 and 2 show field-induced slow magnetic relaxation that arises from the single pseudo- T d Co II ion present. The structural distortion leads to an easy-axis magnetic anisotropy ( D = -31.31 cm -1 for 1 and -21.88 cm -1 for 2) and a small but non-negligible transverse component ( E/ D = 0.11 for 1 and 0.08 for 2). The theoretical studies also reveal how the O-Co-O bond angles and the interplanar angles control D and E values in 1 and 2. The presence of two diamagnetic {Co 2 (μ-L)} hosts controls the distortion of the central {CoO 4 } unit, highlighting a strategy to control single-ion magnetic anisotropy by trapping single ions within a diamagnetic coordination environment.

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 [capital Upsilon]III or GdIII ions allows for a comprehensive understanding of the magnetic behaviour.

Two new air-stable axial Dy(iii) single-ion magnets, [Dy(H2O)5(HMPA)2]Cl3·HMPA·H2O (1) and [Dy(H2O)5(HMPA)2]I3·2HMPA (2) (HMPA = hexamethylphosphoramide), exhibit magnetic hysteresis which remains open up to 9 K for 1@Y and 10 K for 2@Y, respectively. Ab initio calculations, using step-by-step elimination of fragments to generate a series of model complexes, reveal that the secondary coordination sphere plays a key role in controlling the magnetisation reversal barrier and predict that the removal of outer-sphere molecules and anions will enhance the barrier further.

We report a trinuclear mixed-valence {CoIICoIII2} complex, where the CoII centre adopts a trigonal bipyramidal geometry, leading to a large, easy-plane magnetic anisotropy and field-induced slow magnetic relaxation with a Raman-like relaxation process.

Purpose: A situational analysis of breast cancer (BC) early detection services was carried out to investigate whether Trinidad and Tobago (T&T) has the framework for successful organized national screening., Methods: An online survey was designed to assess the availability, accessibility, quality control and assurance (QC&A), and monitoring and evaluation (M&E) mechanisms for public and private BC early detection. A focus group with local radiologists (n = 3) was held to identify unaddressed challenges and make recommendations for improvement., Results: Major public hospitals offer free detection services with wait times of 1-6 months for an appointment. Private institutions offer mammograms for TTD$240 (USD$37) at minimum with same day service. Both sectors report a lack of trained staff. Using 1.2 mammograms per 10,000 women ≥40 years as sufficient, the public sector's rate of 0.19 mammograms per 10,000 women ≥40 years for screening and diagnosis is inadequate. Program M&E mechanisms, QC&A guidelines for machinery use, delays in receipt of pathology reports, and unreliable drug access are further unaddressed challenges., Conclusion: T&T must first strengthen its human and physical resources, implement M&E and QC&A measures, strengthen cancer care, and address other impediments to BC early detection before investing in nationally organized BC screening.

Understanding and controlling magnetic anisotropy at the level of a single metal ion is vital if the miniaturisation of data storage is to continue to evolve into transformative technologies. Magnetic anisotropy is essential for a molecule-based magnetic memory as it pins the magnetic moment of a metal ion along the easy axis. Devices will require deposition of magnetic molecules on surfaces, where changes in molecular structure can significantly alter magnetic properties. Furthermore, if we are to use coordination complexes with high magnetic anisotropy as building blocks for larger systems we need to know how magnetic anisotropy is affected by structural distortions. Here we study a trigonal bipyramidal nickel(ii) complex where a giant magnetic anisotropy of several hundred wavenumbers can be engineered. By using high pressure, we show how the magnetic anisotropy is strongly influenced by small structural distortions. Using a combination of high pressure X-ray diffraction, ab initio methods and high pressure magnetic measurements, we find that hydrostatic pressure lowers both the trigonal symmetry and axial anisotropy, while increasing the rhombic anisotropy. The ligand-metal-ligand angles in the equatorial plane are found to play a crucial role in tuning the energy separation between the d x 2 - y 2 and d xy orbitals, which is the determining factor that controls the magnitude of the axial anisotropy. These results demonstrate that the combination of high pressure techniques with ab initio studies is a powerful tool that gives a unique insight into the design of systems that show giant magnetic anisotropy.

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

Two isostructural polymetallic complexes [Mn(μ 3 -O) 2 (CH 3 COO) 4 (L1) 4 ] - and [Mn(μ 3 -O) 2 (CH 3 COO) 4 (L2) 4 ] - have been synthesised by using two Schiff base ligands derived from 3,5-diamino-1,2,4-triazole, following two different preparative routes, either using the pre-formed ligand (for L1) or via a metal-mediated template synthesis (for L2). The {Mn} structure is unusual, being based on two corner-sharing perpendicular {Mn 3 } triangles forming a twisted bow-tie. The magnetic studies reveal antiferromagnetic coupling between Mn(iii) ions while electrochemical experiments are consistent with a quasi-reversible Mn(iii)↔Mn(iv) redox process at the central manganese ion.

The solvothermal reaction between Ce(NO 3 ) 3 ·6H 2 O, 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 [CeCe ] keplerate cage.