Reaction of di-tert-butyl thioketene S-oxide with Lawesson reagent gave 3,3-di-tert-butylthiirane-2-thione in 88% yield. Oxidation of thiirane-2-thione with m-chloroperbenzoic acid afforded 3,3-di-tert-butylthiirane-2-thione S-oxide. The reaction of thiirane-thione was described.

Ruthenium (Ru) has drawn attention in the field of future semiconductor processing as a diffusion barrier layer and an electrode material. Here, ruthenium films are deposited by atomic layer deposition (ALD) using a novel precursor, Ru2{μ2-η3-N­(tBu)–C­(H)–C­(iPr)}­(CO)6 (T-Rudic), and two different co-reagents, that is, H2O and O2. Ru films are deposited at 0.1 Å/cycle at 150 °C with H2O and 0.8 Å/cycle at 200 °C with O2. The H2O reactant set exhibits ALD saturation between 150 and 200 °C. However, the O2 reactant set shows a linear incremental growth rate over 200 °C and nongrowth under 175 °C. Film growth preference is observed on various substrates (e.g., Si, SiO2, Al2O3, and graphitic carbon) when the H2O reactant is applied at 150 °C. Both experimental data and density functional theory calculations indicate that preferential growth occurs on a hydrogen-terminated surface (Si) rather than a hydroxyl-terminated surface (SiO2). The Auger electron spectroscopy mapping image of a selectively deposited Ru film on a patterned Si and SiO2 substrate supports that this selective deposition mechanism also occurs in a square-patterned substrate.

Single‐atom Pt catalyst has seen a tremendous surge in the research community in very recent times. The minimum loading of such precious metal catalysts on high surface area substrates with effective performance toward catalyzing a reaction is indeed of great importance. Here, an alternative way is demonstrated to perform an ultralow loading of Pt catalyst by atomic layer deposition (ALD) using dimethyl ((3,4‐η) N,N‐dimethyl‐3‐butene‐1‐amine‐N) platinum precursor (C8H19NPt). The ultralow loading of Pt catalyst is performed on highly porous nitrogen–carbon‐powder coated carbon cloth (NC–CC) substrates by varying the number of ALD cycles (2 to 60), and their performance in electrochemical hydrogen evolution reaction (HER) is evaluated. The inductively coupled plasma‐optical emission spectrometry provides the exact mass of the Pt catalyst, whereas, the transmission electron microscopy images confirm the uniform and homogeneous dispersion of platinum single‐atoms and clusters (with an average size of <1 nm for ten ALD cycles) on the NC–CC substrate. It is further found that the mass activity of Pt catalyst (per microgram of Pt) toward HER is extraordinarily high for less number of ALD cycles (two and five), whereas, the overall performance (current density per geometrical area) becomes more and more improved with increasing the ALD cycles.

Atomic layer deposition (ALD) is an advanced technology that can be used to deposit extremely thin and conformal films of iridium (Ir). However, ALD techniques for Ir coating are not well-developed. In particular, new Ir precursors with high reactivity at a suitable low temperature are essentially required. In this study, we report a novel ALD precursor with improved reactivity by introducing a cyclopropenyl ligand. Tricarbonyl (1,2,3-η)-1,2,3-tri(tert-butyl)-cyclopropenyl iridium (C 18 H 27 IrO 3 or TICP) is used as an ALD precursor with molecular O 2 as a reactant. Ir films are grown by ALD on a Si substrate at deposition temperatures ranging from 200 to 325 °C, and an ALD window of 250−275 °C and self-limiting growth at a rate of 0.52 Å cycle −1 at 250 °C are observed. The negligible O impurity content (<2 at. %) and low resistivity (13 μΩ cm) indicate that pure metallic Ir films are formed. The differential delay of nucleation depending on the substrate surface is explained in terms of the dominant surface functional group, indicating possible application of the current ALD process toward area-selective deposition of Ir. Density functional theory calculations show that the adsorption of the Ir precursor is feasible on Si and Ru but is unfavorable on hydroxyl-terminated SiO 2 . Ru is adopted as the seed layer for conformal deposition on a SiO 2 trench, and a step coverage of ∼100% is obtained. Finally, an Ir thin film grown on a threedimensional titanium substrate shows overpotentials (at 10 mA cm −2 ) of ∼65 mV for the hydrogen evolution reaction and ∼336 mV for the oxygen evolution reaction in an acid electrolyte, which suggest its potential application as a water-splitting catalyst.

High-quality Pt thin films are prepared by atomic layer deposition (ALD) using metal-organic precursors dimethyl-(N,N-dimethyl-3-butene-1-amine-N) platinum (C8H19NPt) and with diluted molecular oxygen (O2) as a reactant. The films are grown at a relatively low temperature of 225 °C on a thermally grown SiO2 substrate, and the process shows all the necessary qualities of an ideal ALD such as self-limiting growth characteristics and a well-defined ALD temperature window between 200 and 250 °C. Noticeably, the current ALD-Pt process shows a very high growth per cycle of 0.167 nm without an incubation period at 225 °C, and perfect conformality is obtained at a dual trench structure (top and bottom width: 40 and 15 nm) with an aspect ratio of around 6.3. The resistivity of the ALD-Pt film at ∼39 nm in thickness deposited at 225 °C is almost the same (∼10.8 μΩ cm) as its bulk resistivity (10.6 μΩ cm), and it is as low as ∼12 μΩ cm at 25 nm in thickness. Comprehensive analyses using x-ray photoelectron spectroscopy, x-ray diffractometry, transmission electron microscopy (TEM), and x-ray reflectance indicate that the extremely low resistivity of ALD-Pt is due to the formation of highly pure and polycrystalline films with high density (∼21.04 g/cm3) and large grain size (∼48 nm for 25 nm thick film). For comparison, ALD-Ru is deposited at the same equipment and deposition temperature, 225 °C, using (ethylbenzene)(1,3-butadiene)Ru(0) (C12H16Ru) and diluted O2 as the reactant. The higher resistivity of ∼20 μΩ cm at a similar thickness (∼23.5 nm) with ALD-Pt is obtained, which is much higher than its bulk value (7.6 μΩ cm). TEM analysis suggests that the formation of relatively smaller-sized grains of ALD-Ru is the main reason for it.