Two mononuclear Dy III crown ether complexes [Dy(15C5)(H 2 O) 4 ](ClO 4 ) 3 Á(15C5)ÁH 2 O (1) and [Dy(12C4)(H 2 O) 5 ](ClO 4 ) 3 ÁH 2 O (2) have been prepared and characterized. X-ray diffraction studies show that both compounds crystallize as half sandwich type structures with muffin and pseudo-capped square antiprismatic geometries respectively. Despite the comparable local environments of the Dy III ions they display remarkably different dynamic magnetic properties with only 1 displaying SMM properties in zero field. The solid state emission spectra for both 1 and 2 display sharp bands associated with f-f transitions.From the fine structure of the 4 F 9/2 -6 H 15/2 band, the Stark splitting of the 6 H 15/2 ground state permitted the energy difference between the ground and first excited state to be determined. For 1 this value (DE = 58.0 AE 3.0 cm À1 ) is in excellent agreement with ab initio calculations and the experimentally observed SMM behaviour. For 2, the photoluminescence data and theoretical calculations support a less well isolated ground state (DE = 30 AE 3.0 cm À1 ) in which a rapid relaxation process affords no SMM behaviour in zero-field.

The first supramolecular cage formed by three benzo-15-crown-5 macrocycles encapsulating a [Dy(OH2)8](3+) guest cation is reported, with the Dy(iii) centre exhibiting local pseudo square antiprismatic D4d symmetry. The anisotropy barrier extracted from ac susceptibility studies, emission spectroscopy and ab initio calculations reveals that the second excited state Kramers doublet plays a key role in the magnetization dynamics due to the Ising character and near coparallel nature of the ground and first excited Kramers doublets.

Two complexes comprising 9-coordinate capped square antiprismatic [Ln(NO)(OH)(MeOH)] units [Ln(III) = Dy 6; Tb 7] are reported in which the metal complexes are hydrogen-bonded to 15C5 (15-crown-5) macrocycles to form supramolecular chains, {[Ln(NO)(OH)(MeOH)]·(15C5)}. Alternating current magnetic susceptibility measurements supported by ab initio studies show field-induced SMM (single-molecule magnet) behavior for 6, but rapid relaxation of the magnetization for 7 because of the presence of dominant quantum tunneling processes as evidenced by the presence of a significant calculated tunnel splitting within the ground-state multiplet. Modeling the high-resolution emission spectra for 6 afforded energies of 37 ± 5 and 28 ± 5 cm for the first-excited-state Stark sublevels of the two crystallographically independent Dy1 and Dy2 ions, in excellent agreement with the calculated values of 31 and 21 cm for ΔE derived from ab initio studies.

Atomic layer deposition (ALD) of elemental antimony was achieved on hydrogen-terminated silicon (H–Si) and SiO2/Si substrates using Sb­(SiMe3)3 and SbCl3 in the temperature range 23–65 °C. The mirrorlike films were confirmed to be composed of crystalline antimony by XPS (for the film deposited at 35 °C) and XRD, with low impurity levels and strong preferential orientation of crystal growth relative to the substrate surface. To the best of our knowledge, this is the first example of room-temperature thermal ALD (with demonstrated self-limiting growth) of a pure element. Film growth at 35 °C exhibited a substrate-enhanced mechanism, characterized by faster film growth for the first ∼125 ALD cycles, where substantial deposition occurs on the original substrate surface (GPC = 1.3 Å/cycle on SiO2/Si and 1.0 Å/cycle on H–Si) and slower film growth (GPC = 0.40 Å/cycle on SiO2/Si and 0.27 Å/cycle on H–Si) after ∼125 cycles, once much of the initial substrate surface has been covered. Films deposited using 500–2000 ALD cycles were shown to be continuous by SEM. The use of less than 250 cycles afforded discontinuous films. However, in this initial growth phase, when the deposition occurs primarily on the original substrate surface, in situ surface pretreatment by Sb­(SiMe3)3 or SbCl3 (50 × 0.4 or 0.8 s pulses) followed by the use of longer precursor pulses (0.4 or 0.8 s) during the first 50 ALD cycles resulted in improved nucleation. For example, on H–Si, a continuous 6.7 nm thick film was produced after initial pretreatment with 50 × 0.8 s pulses of SbCl3, followed by 50 ALD cycles using 0.8 s pulses. The use of longer pulses in the first 50 ALD cycles following surface pretreatment is likely required to achieve complete reactivity with an increased density of reactive surface sites.

Reaction of one equivalent of H 2 (acen), H 2 (cis-Cyacen) or H 2 (trans-Cyacen) with [Zr(CH 2 SiMe 3 ) 4 ] at room temperature afforded [Zr(acen)(CH 2 SiMe 3 ) 2 ] (1), [Zr(cis-Cyacen)(CH 2 SiMe 3 ) 2 ] (2) or [Zr(trans-Cyacen)(CH 2 SiMe 3 ) 2 ] (3), respectively (acen = C 2 H 4 (NCMeCHC(O)Me) 2 ; Cyacen = 1,2-C 6 H 10 (NCMeCHC(O)Me) 2 ). These alkyl compounds are trigonal prismatic in the solid state, and whereas 1 and 3 decomposed without sublimation above 120 °C (5-10 mTorr), 2 sublimed in > 95 % yield at 85 °C (5-10 mTorr). However, heating solid 2 at 88 °C under static argon for 24 hours resulted in extensive decomposition to afford H 2 (cis-Cyacen) and SiMe 4 as the soluble products. Compound 2 reacted cleanly with two equivalents of t BuOH to afford [Zr(cis-Cyacen)(O t Bu) 2 ] (4), but excess t BuOH caused both SiMe 4 and H 2 (cis-Cyacen) elimination. The 1 : 1 reaction of H 2 (acen) with [Zr(NMeEt) 4 ] did not proceed cleanly, and 8-coordinate [Zr-(acen) 2 ] (5) was identified as a by-product; this complex was isolated from the 2 : 1 reaction. A zirconium amido complex, [Zr(acen)(NMeEt) 2 ] (6) was accessed via the reaction of 1 with two equiv. or excess HNMeEt, but decomposed readily in solution at room temperature. More sterically hindered [Zr-(acen){N(SiMe 3 ) 2 } 2 ] (7) was synthesized via the reaction of [Zr(acen)Cl 2 ] with two equivalents of Li{N(SiMe 3 ) 2 }, but was also thermally unstable as a solid and in solution at room temperature. Compounds 1-3, 5 and 7 were crystallographically characterized.