Yu-Mei Lin

[Ag(70)(PW(9)O(34))(2)((t)BuC[triple bond, length as m-dash]C)(44)(H(2)O)(2)](8+): ionothermal synthesis of a silver cluster encapsulating lacunary polyoxometalate ions.

A silver alkynyl cluster containing a Ag70 shell and two lacunary [PW9O34](9-) templating ions was synthesized by an ionothermal approach. Fast core-shell electronic communication between silver(i) centers and polyoxometalates was verified via cyclic voltammetry studies in [BMIm]BF4.

Annulation of Metallabenzenes: From Osmabenzene to Osmabenzothiazole to Osmabenzoxazole**

Research into transition-metal-containing metallaaromatics is attracting considerable current attention. Since the first example of metallabenzenes were reported by Roper et al. in 1982, a wide variety of monocyclic metallaaromatics have been successfully isolated and characterized. However, the chemistry of fused metallaaromatics is less developed. Most of the reported fused metallaaromatics were constructed by the cyclometalation of an unsaturated precursor. 7] Only one exceptional example, based on the metal insertion reaction of benzothiophene, has been reported. In principle, it may be another efficient approach to construct fused metallaaromatics from monocyclic metallaaromatics; however, such a possibility has not been realized to date. Herein, we report a novel annulation reaction leading to the first metallabenzothiazole 2 based on the intramolecular nucleophilic aromatic substitution (SNAr) reaction of metallabenzene 1. Furthermore, transformation of 2 to the first metallabenzoxazoles 4 and 5 is also presented (Scheme 1). It is now well-established that arenes, and especially heteroarenes, could undergo SNAr reaction if electron-withdrawing substituents are positioned ortho or para to the leaving group (typically a halogen) on the ring. Recently, we reported the synthesis of osmabenzene 1 bearing a phosphonium substituent and a reactive thiocyano group on the metallacycle. In this system, the metal center and the electron-withdrawing phosphonium group may exert significant influence on the electron density of the aromatic ring. In this regard, complex 1 might be expected to undergo intramolecular SNAr reactions to construct new metallaaromatic compounds. With this idea in mind, we studied the reaction of osmabenzene 1 with MeONa/MeOH, from which osmabenzothiazole 2 was isolated as a green solid (Scheme 1). This new product is air-stable and can be kept for several days without appreciable decomposition either in the solid state or in solution at room temperature. The structure of 2 has been confirmed by X-ray diffraction. As shown in Figure 1, it contains a perfectly planar metallabenzothiazole unit. The maximum deviation from the least-squares plane of the whole metallabenzothiazole system is 0.0096 . As expected, the lengths of the Os1 C1 (1.954(7) ) and Os1 C5 (1.953(8) ) and the C C bonds within the osmabenzene ring are within the range of those observed for other osmabenzenes. 9] The C N and C S bond lengths of the thiazole moiety are similar to those

Osmabenzenes from Osmacycles Containing an η2‐Coordinated Olefin

Treatment of HC[triple bond]CC(CH3)(OH)CH=CH2 with [OsCl2(PPh3)3] in dichloromethane yielded the eta2-olefin-coordinated osmacycle [Os{CH=C(PPh3)C(=CH2)-eta2-CH=CH2}Cl2(PPh3)2] (9). Transformations of osmacycle 9 by treatment with benzonitrile under various conditions have been investigated. Reaction of 9 with excess benzonitrile at room temperature afforded the dicationic osmacycle [Os{CH=C(PPh3)C(=CH2)-eta2-CH=CH2}(PhCN)2(PPh3)2]Cl2 (11) by ligand substitution, which reacted further to the intramolecularly coordinated eta2-allene complex [Os{CH=C(PPh3)C(CH3)=(eta2-C=CH2)}(PhCN)2(PPh3)2]Cl2 (12). In contrast, heating a chloroform solution of 9 to the reflux temperature in the presence of excess benzonitrile generated osmabenzene [Os{CHC(PPh3)C(CH3)CHCH}(PhCN)2(PPh3)2]Cl2 (14). Complexes 11, 12 and 14 are in fact isomers. In the absence of excess benzonitrile, the isolated dicationic 12 and 14 readily dissociate the benzonitrile ligands in solution to produce the neutral complex [Os{CH=C(PPh3)C(CH3)=(eta2-C=CH2)}Cl2(PPh3)2] (13) and the monocationic osmabenzene [Os{CHC(PPh3)C(CH3)CHCH}Cl(PhCN)(PPh3)2]BPh4 (15), respectively. Mechanisms for the formation of osmabenzene 14 from 11 and 12 are proposed based on DFT calculations.

Chloride-Promoted Formation of a Bimetallic Nanocluster Au80Ag30 and the Total Structure Determination

We report the total structure determination of a large bimetallic nanocluster with an overall composition of [Au80Ag30(C≡CPh)42Cl9]Cl. It is the largest structurally characterized bimetallic coinage nanocluster so far. The 110 metal atoms are distributed in a concentric four-shell Russian doll arrangement, Au6@Au35@Ag30Au18@Au21. There are 42 PhC≡C- ligands and 9 μ2-chloride ligands clamping on the cluster surface. The chloride is proven to be critical for the formation of this giant cluster, as the control experiment in the absence of halide gives only smaller species. This work demonstrates that the halide can play a key role in the formation of a large metal nanocluster, and the halide effect should be considered in the design and synthesis of metal nanoclusters.

Thiacalix[4]arene: New protection for metal nanoclusters

An organic macrocycle ligand is promising in precisely controlling the structures and optical properties of silver nanoclusters. Surface organic ligands are critical for the formation and properties of atomically precise metal nanoclusters. In contrast to the conventionally used protective ligands such as thiolates and phosphines, thiacalix[4]arene has been used in the synthesis of a silver nanocluster, [Ag35(H2L)2(L)(C≡CBut)16](SbF6)3, (H4L, p-tert-butylthiacalix[4]-arene). This is the first structurally determined calixarene-protected metal nanocluster. The chelating and macrocyclic effects make the thiacalix[4]arene a rigid shell that protects the silver core. Upon addition or removal of one silver atom, the Ag35 cluster can be transformed to Ag36 or Ag34 species, and the optical properties are changed accordingly. The successful use of thiacalixarene in the synthesis of well-defined silver nanoclusters suggests a bright future for metal nanoclusters protected by macrocyclic ligands.

1,2-Migration in the reactions of ruthenium vinyl carbene with propargyl alcohols

Reactions of the ruthenium vinyl carbene complex [Ru{CHC(PPh3)CH(2-Py)}Cl2PPh3]BF4 (1) with five propargyl alcohols HCCC(OH)R1R2, (R1 = R2 = Ph; R1 = Ph, R2 = CH3; R1 = H, R2 = Ph; R1 = H, R2 = CH3; R1 = CHCH2, R2 = CH3) have been investigated, which led to the formation of several ten-membered η2-olefin coordinated ruthenacycles [Ru{OCR2CHR1-η2-CHCHC(PPh3)CH(2-Py)}Cl2PPh3]BF4 (R1 = R2 = Ph, 2; R1 = Ph, R2 = CH3, 3; R1 = H, R2 = Ph, 4; R1 = H, R2 = CH3, 5; R1 = CHCH2, R2 = CH3, 6), respectively. In these reactions, insertion of alkynes and intramolecular 1,2-migration of propargyl alcohols were performed in tandem. The results show that the 1,2-migratory preference of the groups is in the order of H > Ph > CH3. Complexes 2, 3, 5, and 6 were characterized by X-ray diffraction analysis and NMR spectra.

Directed formation of tri-connected Cu(I) coordination polymers

Two new tri-connected copper(I) coordination polymers have been synthesized, featuring a 1D staircase-like structure and an interpenetrating 2D polycyclohexane framework. The geometries are controlled by steric factors that are generated from the terminal blocking ligand 2-diphenylphosphino-n-methyl pyridine (n = 3, 6) with the methyl group at different substituted positions.

[MnIIIMnIV2Mo14O56]17–: A Mixed-Valence Meso-Polyoxometalate Anion Encapsulated by a 64-Nuclearity Silver Cluster

A 64-nuclearity silver cluster encapsulating a unique POM anion [Mn(III)Mn(IV)2Mo14O56](17-) has been synthesized. The formation of the templating core performs a reassembly process for increasing nuclearities from {MnMo9} to {Mn3Mo14}. It represents a rare inorganic meso anion containing mixed-valent Mn that is built up by d-{Mn(IV)Mo7} and l-{Mn(IV)Mo7} units connecting together through a {Mn(III)} fragment.

Synthesis and characterization of a bimetallic iridium complex with a ten sp2-carbon chain bridge

A special sp2-carbon chain bridged bimetallic iridium complex has been synthesized and characterized; the compound has excellent air-stability, thermo-stability and electrochemical properties.

Ligand-Controlled Doping Effects in Alloy Nanoclusters Au4Ag23 and Au5Ag24

The syntheses and properties of two bimetallic nanoclusters [Au4 Ag23 (C≡CtBu)10 (dppf)4 Cl7 ](PF6 )2 and [Au5 Ag24 (C≡CC6 H4 -p-tBu)16 (dppf)4 Cl4 ](PF6 )3 are reported. The Au atoms distributed in both the cores and the surface motifs are clearly determined. The two nanoclusters show distinctly different geometric structures and electronic properties, which are attributed to the subtle changes in the surface alkynyl structures.