Four hexanuclear molybdenum chloride cluster complexes containing terminal thiolate ligands have been synthesized and fully characterized. (Bu4N)2[Mo6Cl8(SEt)6] was prepared by reacting Na2[Mo6Cl8(OMe)6] with an excess of ethanethiol in refluxing tetrahydrofuran. (PPN)2[Mo6Cl8(SBu)6], (Bu4N)2[Mo6Cl8(SBn)6], and (Bu4N)2[Mo6Cl8(SNC8H6)6] (C8H6NS− = 3-indolylthiolate) were subsequently prepared in the reaction of [Mo6Cl8(SEt)6]2− with an excess of HSR (R = Bu, Bn or 3-indolyl). Single crystal X-ray diffraction analyses were performed on two of these complexes: (PPN)2[Mo6Cl8(SEt)6]·Et2O, crystallizes in the triclinic space group P1 with a = 12.3894(11), b = 13.7651(12), c = 15.0974(13), α = 103.975(2), β = 99.690(2), γ = 98.062(2), and Z = 1; (PPh3Me)2[Mo6Cl8(SBn)6]·2NO2CH3, also crystallizes in the P1 space group with a = 12.1574(16), b = 13.4441(17), c = 14.2132(18), α = 89.654(2), β = 88.365(2), γ = 71.179(2), and Z = 1. Our studies demonstrate that [Mo6Cl8(SEt)6]2− displays luminescent properties and th...

Synthesis and study of hexanuclear molybdenum clusters containing thiolate ligands.

In this contribution, we present a review of our recent works about the design of phosphor nanoparticles and materials based on [Mo6X14]2− cluster units (X = Cl, Br, I) as well as the functionalization of monocrystalline Si(111) surfaces by Mo6 clusters. Our purpose was to use the specific properties of cluster units found in inorganic solids for the design of new nanomaterials with potential applications in nanotechnologies (e.g. phosphor dyes for bio labelling, light emitting diodes, redox active molecular junctions…) using soft chemistry techniques. Phosphor Cs2Mo6X14@SiO2 nanoparticles emitting in 550–900 nm upon photo-excitation were synthesised using a ‘water in oil’ microemulsion technique. They exhibit a regular shape (~45 nm) and are based on [Mo6X14]2− cluster units and Cs+ counter cations embedded in a silica matrix. ((n–C4H9)4N)2Mo6Br14@ZnO colloids and nanopowders are based on the association of ZnO crystalline nano-particles with Mo6 cluster units adsorbed on their surface. They exhibit a large emission window in the visible region that can be tuned by modulation of the excitation wave length in order to selectively obtain the emission of either clusters units or ZnO nanocrystals or of both entities. Functionalized surfaces were obtained by the attachment of cluster units on a Si(111) surface through pyridine end capped organic chains using a multi-step procedure. Modified surfaces were characterized by X-ray photoemission spectroscopy (XPS), atomic force microscopy (AFM), IR and electrochemical analysis. The surface coverage can be modulated by the controlled introduction of inert organic chains among pyridine end-capped ones before the cluster anchoring step.

Novel Nanomaterials Based on Inorganic Molybdenum Octahedral Clusters

Octahedral molybdenum cluster cores [Mo6I8]4+ have been attached in apical positions to p- and n-type Si(111) surfaces through complexation with a pyridine-terminated organic monolayer (2 × 1014 cm−2), which was previously covalently bound to hydrogen-terminated Si(111). This grafting procedure resulted in about a 4 nm thick Mo6-terminated layer. Similar XPS results were found for p- and n-type samples, suggesting that the grafting efficiency and composition of the resulting layers do not depend significantly on the doping type of the surface. The cluster footprint of 10 nm2 indicates a fairly dense molecular packing on the Si(111) surface. The electrochemistry of such Mo6-modified surfaces in acetonitrile was characterized by a single irreversible oxidation peak at 0.92 V versus saturated calomel electrode (SCE) and flat band potential Efb values of −0.55 ± 0.05 V and 0.04 ± 0.05 V for the modified n- and p-type surfaces, respectively. The derivatization of silicon surfaces by Mo6 introduces surface stat...

Electrochemical and Charge Transport Behavior of Molybdenum-Based Metallic Cluster Layers Immobilized on Modified n- and p-Type Si(111) Surfaces

The article contains sections titled:



1.	Introduction	
2.	Properties	
3.	Occurrence	
3.1.	Minerals	
3.2.	Deposits	
4.	Production	
4.1.	Concentration	
4.2.	Processing of Concentrate	
4.3.	Recovery from Spent Petroleum Catalysts	
4.4.	Recovery during Production of Tungsten Ores	
4.5.	Production of Molybdenum Metal Powder	
4.6.	Production of Compact Molybdenum Metal	
4.7.	Processing of Molybdenum	
4.8.	Molybdenum-Base Alloys	
5.	Uses	
6.	Production of Ferromolybdenum	
6.1.	Ferromolybdenum Grades	
6.2.	Raw Materials	
6.3.	Submerged Arc Furnace Carbothermic Reduction	
6.4.	Metallothermic Reduction	
7.	Molybdenum Compounds	
7.1.	Overview of Molybdenum Chemistry	
7.2.	Molybdenum Oxides	
7.3.	Molybdenum Chalcogenides	
7.4.	Molybdenum Halides	
7.5.	Molybdates, Isopolymolybdates, and Heteropolymolybdates	
7.6.	Other Molybdenum Compounds	
8.	Uses of Molybdenum Compounds	
8.1.	Catalysis	
8.2.	Lubrication	
8.3.	Corrosion Inhibition	
8.4.	Flame Retardancy and Smoke Suppression	
8.5.	Pigments	
8.6.	Agriculture	
9.	Analysis	
10.	Economic Aspects	
11.	Environmental Aspects	
12.	Toxicology and Occupational Health

Molybdenum and Molybdenum Compounds

Die Reaktion von Mo6Cl12 mit zwei Aquivalenten Natriummethanolat fuhrt in Gegenwart von 2,2,2-crypt zu (C18H36N2O6Na)2[Mo6Cl12(OCH3)2] (1). Durch Metathese von 1 mit 9-Anthrylmethanol in Propylencarbonat wird (C18H36N2O6Na)2[Mo6Cl12(OC15H11)2] · 2C4H6O3 (2) erhalten. Die Strukturbestimmung an Einkristallen (1: C2/m, a=25,513(8) A, b=13,001(3) A, c=10,128(3) A, β=100,204(12)°; 2: C2/c, a=15,580(5) A, b=22,337(5) A, c=27,143(8) A, β=98,756(10)°) zeigt, das in beiden Verbindungen Clusteranionen der Zusammensetzung [Mo6ClCl(ORa) 2]2− mit zwei zueinander trans-standigen terminalen Alkoholatliganden vorliegen (1: d(Mo—Mo) 2,597(2) A bis 2,610(2) A, d(Mo—Cli) 2,471(3) A bis 2,493(4) A, d(Mo—Cla) 2,417(8) A und 2,427(8) A, d(Mo—O) 2,006(13) A; 2: d(Mo—Mo) 2,599(3) A bis 2,628(3) A, d(Mo—Cli) 2,468(8) A bis 2,506(7) A, d(Mo—Cla) 2,444(8) A bzw. 2,445(7) A, d(Mo—O) 2,012(19) A).

Molybdänhalogenidcluster mit zwei terminalen Alkoholatliganden: Synthese und Kristallstrukturen von (C18H36N2O6Na)2[Mo6Cl12(OCH3)2] und (C18H36N2O6Na)2[Mo6Cl12(OC15H11)2] · 2C4H6O3

S.I. Erzerum

Papers

Convenient synthesis of the hexanuclear molybdenum(II) halides Mo6Cl12 and Mo6Br12·2H2O