Organometallic Ionic Plastic Crystals Incorporating Cationic Half-Sandwich Complexes.

Ionic plastic crystals (IPCs), characterized by nearly spherical molecular ions, exhibit remarkable solid-state characteristics including high ionic conductivity. However, most IPCs are organic onium salts. Incorporating organometallic half-sandwich complexes into IPCs is challenging owing to their low-symmetry structures. This paper introduces a novel series of IPCs composed of salts derived from half-sandwich organometallic complexes. We synthesized five salts of [Ru(Cp)(tmeda)(CO)]X (tmeda = N,N,N',N'-tetramethyl-1,2-ethanediamine, X = anion) with different anions and examined their phase behavior, crystal structures, and molecular motion in the solid-state. Salts featuring the CPFSA (= 1,1,2,2,3,3-hexafluoropropane-1,3-disulfonimide), B(CN)4-, and FSA- (= (FSO2)2N-) anions underwent phase transitions to an IPC phase with a CsCl-type structure in the temperature range of 327-364 K. Employing smaller anions led to an increase in the transition temperature. In each salt, the coordination number, representing the number of anions surrounding one cation, remained eight in IPC and low-temperature phases. However, salts containing smaller anions (CF3BF3- and PF6-) displayed a rotator phase rather than the IPC phase. In these cases, the coordination numbers were six at low temperatures.

Mechanistic Insights on the Formation of a Carbodiimide Ion from Urea in La2O2NCN Synthesis Based on the "Proanion" Strategy.

This study affords mechanistic insights into the formation mechanism of carbodiimide ions (NCN2-) from urea during the synthesis of La2O2NCN by employing the "proanion" strategy without using NH3 gas. It is a safer, cost-effective, and environmentally friendly approach. Urea, acting as a proanion, decomposes upon heating, facilitating conversion to NCN2-. This work meticulously examines the phase transitions and identifies intermediate species formed during the reaction using in situ X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric-differential thermal analysis-mass spectrometry. The findings present a detailed mechanism in which urea initially decomposes at 140 °C, releasing HNCO, which reacts with La(OH)3 to immobilize NCO- species on the surface of La(OH)3. As the temperature reaches approximately 400 °C, these NCO- anions transform into NCN2- anions by releasing CO2 gas, resulting in the formation of an amorphous phase rich in NCN2-. Following further heating to 600 °C, La2O2NCN crystallizes, enhancing its crystallinity as the temperature increases. These findings elucidate the formation mechanism of La2O2NCN, introduce the "proanion method" for the alternative synthesis of metal (oxy)carbodiimides, and expand their potential for applications as functional materials.

Silver(I) Sulfide Clusters Protected by Rhodium(III) Metalloligands with 3-Aminopropanethiolate.

The two homochiral AgIRhIII nanoclusters, Δ6/Λ6-[Ag11S{Rh(apt)3}6]9+ ([1]9+) and Δ6/Λ6-[Ag13S{Rh(apt)3}6]11+ ([2]11+), in which Ag11S and Ag13S cluster cores, respectively, are protected by fac-[Rh(apt)3] metalloligands, were newly synthesized from fac-[Rh(apt)3] (Hapt = 3-aminopropanethiol) and Ag+ in water in combination with sulfide sources. While [1]9+ was produced by using d-penicillamine as a sulfide source, the use of HS- as a sulfide source afforded [2]11+ without causing any precipitation of Ag2S. Cluster [1]9+ was convertible to [2]11+ via the reaction with Ag+, which led to a turn-on-type switch in photoluminescence from nonemissive [1]9+ to emissive [2]11+.

Structurally Precise Silver Sulfide Nanoclusters Protected by Rhodium(III) Octahedra with Aminothiolates.

A 60-nuclear silver sulfide nanocluster with a highly positive charge (1) has been synthesized by mixing an octahedral RhIII complex with 2-aminoethanethiolate ligands, silver(I) nitrate, and d-penicillamine in water under mild conditions. The spherical surface of 1 is protected by the chiral octahedral RhIII complex, with cleavage of the C-S bond of the d-penicillamine supplying the sulfide ions. Although 1 does not contain d-penicillamine, it is optically active because of the enantiomeric excess of the RhIII molecules induced by chiral transfer from d-penicillamine. 1 can accommodate/release external Ag+ ions and replace inner Ag+ ions by Cu+ ions. The study demonstrates that a thiolato metal complex and sulfur-containing amino acid can be used as cluster-surface-protecting and sulfide-supplying regents, respectively, for creating chiral, water-soluble, structurally precise silver sulfide nanoclusters, the properties of which are tunable through the addition/removal/exchange of Ag+ ions.

Sulfide-Induced Dimerization Versus Demetallation of Tricopper(I) Clusters Protected by Tris-Thiolato Metalloligands.

Here, we report the reactivity of copper(I) clusters toward sulfide ions; these sulfide copper(I) clusters have attracted much attention due to their relevance to biologically active centers and their fascinating structural and photophysical properties. Treatment of the CuI 3RhIII 2 pentanuclear complex, [Cu3{Rh(aet)3}2]3+ (aet=2-aminoethanethiolate), in which a {CuI 3}3+ cluster moiety is bound by two fac-[Rh(aet)3] metalloligands, with NaSH in water produced the CuI 6RhIII 4 decanuclear complex, [Cu6S{Rh(aet)3}4]4+, accompanied by the dimerization of [Cu3{Rh(aet)3}2]3+ and the incorporation of a sulfide ion at the center. While similar treatment using the analogous CuI 3IrIII 2 complex with fac-[Ir(aet)3] metalloligands, [Cu3{Ir(aet)3}2]3+, produced the isostructural CuI 6IrIII 4 decanuclear complex, [Cu6S{Ir(aet)3}4]4+, the use of the CuI 3RhIII 2 complex with fac-[Rh(apt)3] metalloligands, [Cu3{Rh(apt)3}2]3+ (apt=3-aminopropanethiolate), resulted in the removal of one of the three CuI atoms from {CuI 3}3+ to afford the CuI 2RhIII 2 tetranuclear complex, [Cu2{Rh(apt)3}2]2+.

Heterometallation of Photoluminescent Silver(I) Sulfide Nanoclusters Protected by Octahedral Iridium(III) Thiolates.

The recently-increasing interest in coinage metal clusters stems from their photophysical properties, which are controlled via heterometallation. Herein, we report homometallic AgI 46 S13 clusters protected by octahedral fac-[Ir(aet)3 ] (aet=2-aminoethanethiolate) molecules and their conversion to heterometallic AgI 43 MI 3 S13 (M=Cu, Au) clusters. The reactions of fac-[Ir(aet)3 ] with Ag+ and penicillamine produced [Ag46 S13 {Ir(aet)3 }14 ]20+ ([1]20+ ), where a spherical AgI 46 S13 cluster is covered by fac-[Ir(aet)3 ] octahedra through thiolato bridges. [1]20+ was converted to [Ag43 M3 S13 {Ir(aet)3 }14 ]20+ ([1M ]20+ ) with an AgI 43 MI 3 S13 cluster by treatment with M+ , retaining its overall structure. [1]20+ was photoluminescent and had an emission band ca. 690 nm that originated from an S-to-Ag charge transfer. While [1Cu ]20+ showed an emission band with a slightly higher energy of ca. 650 nm and a lower quantum yield, the emission band for [1Au ]20+ shifted to a much higher energy of ca. 590 nm with an enhanced quantum yield.