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The reactions of [Cp*IrCl2]2 (Cp* = pentamethylcyclopentadienyl) with [M6O19]8- (M = Nb, Ta) anions lead to the formation of new hybrid organometallic-polyoxometalate (organometallic-POM) complexes, namely, single-capped Na8[H2{Cp*IrNb6O18}2(O)] ·47H2O (Na8-IrNb12) and Na6[{Cp*Ir}Ta6O19] ·27H2O (Na6-IrTa6) as well as double-capped trans-[{Cp*Ir}2M6O19]4- complexes. Their solution behavior was studied by NMR spectroscopy and ESI-MS techniques. Cyclic voltammetry (CV) experiments demonstrated efficient electrocatalytic water oxidation in the presence of trans-[{Cp*Ir}2Nb6O19]4-. [ABSTRACT FROM AUTHOR]

The gas-phase fragmentation reactions of Keggin-type [PW11O39MCl]5- (M = Rh, Ir) polyoxometalates (POMs) featuring chloride terminal ligands have been investigated. Different adducts of the general formulas [PW11O39MCl + 2cat]3- and [PW11O39MCl + 3cat]2- [cat = alkylammonium cations (Me4N+, Bu4N+), alkali cations (Na+, K+) or protons] were subjected to collision-induced dissociation (CID) conditions. The (cat)Cl (cat = H+, Na+ or K+) fragments were released as a common fragmentation pathway and were taken as a fingerprint of the ligands attached at the noble metal site. Other {PW11O39ML} POMs (M = Rh, Ir) with L = thiocyanate, nitrite, methyl, phenylacetate or phenyl were identified on the basis of CID experiments. Coordination studies of thiocyanate anions and CO to {PW11O39Ru} POMs to yield the new compounds [PW11O39RuSCN]5- and [PW11O39RuCO]4- are also reported. CID experiments were also used to validate that thiocyanate and CO ligation at the Ru metal site had occurred. [ABSTRACT FROM AUTHOR]

Molybdenum(IV) hydroxo [Mo3S4(dmpe)3(OH)3]+ ( 1+) and hydrosulfido [Mo3S4(dmpe)3(SH)3]+ ( 2+) [dmpe = 1,2-bis(dimethylphosphanyl)ethane] trimetallic cuboidal cluster complexes have been isolated in high yields by treating their chloride precursors with sodium hydroxide or sodium hydrosulfide, respectively. The crystal structures of [ 1]BPh4 and [ 2]PF6 confirm that -QH (Q = O, S) groups are coordinated to metal centers. Both hydroxo and hydrosulfido Mo3S4 cluster complexes are fully characterized by spectroscopic, mass spectrometric, and X-ray techniques. A comparative study of the gas-phase dissociation of 1+ and 2+ cations using ESI tandem mass spectrometry is presented, and the results are compared with those already reported for the hydroxo tungsten analogue. The gas-phase reactivity of 1+ and 2+ species towards ethanol and 1-penthanethiol have been explored. The gas-phase-generated [Mo3S4(dmpe)2(O)(OH)]+ cation activates ethanol molecules through a similar mechanism to that proposed for its tungsten congener. The main differences in aldehyde elimination under collision-induced dissociation (CID) conditions between molybdenum and tungsten cluster sulfides are discussed. [ABSTRACT FROM AUTHOR]

The coordination chemistry of dithiolene and diselenolene ligands towards the all-selenium [Mo3Se7Br6]2- dianion has been investigated. Complexes ( nBu4N)2[Zn(dmit)2] (dmit = 1,3-dithia-2-thioxo-4,5-dithiolate) and ( nBu4N)2[Zn(dsit)2] (dsit = 1,3-dithia-2-thioxo-4,5-diselenolate) were employed as ligand precursors. The ( nBu4N)2[Zn(dmit)2] complex in acetonitrile at reflux showed unexpected reactivity with [Mo3Se7Br6]2- dianion in which the inner Se atoms were replaced by S (all but the μ3-Se atom) to afford a series of mixed chalcogen [Mo3Se7- xS x(dmit)3]2- ( x = 0-6) dianions. Reaction of the [Mo3S4Se3Br6]2- dianion with ( nBu4N)2[Zn(dmit)2] under similar conditions also produced a mixed dmit-containing cluster formulated as [Mo3S7- xSe x(dmit)3]2- ( x = 0-3). The reactions were conveniently monitored by electrospray ionization mass spectrometry. The reactions of ( nBu4N)2[Zn(dmit)2] and ( nBu4N)2[Zn(dsit)2] with the [Mo3Se7Br6]2- dianion in dichloromethane at room temperature prevented chalcogen scrambling and allowed us to isolate the cluster salts ( nBu4N)2[Mo3Se7(dmit)3] {( nBu4N)2[ 1]} and ( nBu4N)2[Mo3Se7(dsit)3] {( nBu4N)2[ 2]} in analytically pure form. The crystallization of ( nBu4N)2[ 1] from dichloromethane/diethyl ether resulted in ( nBu4N)2[Mo3Se6.1S0.9(dmit)3] with partial substitution of the Seeq atoms in the cluster core. The crystal structure of ( nBu4N)2[Mo3Se6.1S0.9(dmit)3] was determined by single-crystal X-ray analysis. Dianionic complexes ( nBu4N)2[ 1], ( nBu4N)2[ 2], and ( nBu4N)2[Mo3Se7- xS x(dmit)3] ( x = 0-6) were partially oxidized by iodine to afford dark semiconducting powders. These solids exhibit moderate electrical conductivities (7 × 10-2 to 6 × 10-3 S cm-1) and present antiferromagnetic exchange interactions and therefore represent new examples of magnetic Mo3Q7-based single-component conductors. [ABSTRACT FROM AUTHOR]

A unique series of unsymmetrically substituted [Mo3S4(dmpe)3Cl3- x(dca) x]PF6 ( x = 0-3) clusters that feature mixed Cl/dca terminal ligands, prepared by thermal reaction of [Mo3S4(dmpe)3Cl3]PF6 ([ 1]PF6) [dmpe = 1,2-bis(dimethylphosphanyl)ethane] with sodium dicyanamide [Na(dca); dca = dicyanamide] is reported. The cluster/Na(dca) ratio, reaction time as well as the nature of the solvent dictate the relative ratio of [Mo3S4(dmpe)3Cl2(dca)]PF6 ([ 2]PF6), [Mo3S4(dmpe)3Cl(dca)2]PF6 ([ 3]PF6) and [Mo3S4(dmpe)3(dca)3]PF6 ([ 4]PF6). An electrospray ionization mass spectrometry (ESI-MS) based protocol was employed for high-throughput optimization of reaction conditions directed to obtain [ 2- 4]PF6 in optimal yield. The incorporation of dca confers significant polarity differences on the [ 2- 4]PF6 series, so that compounds [ 2- 4]PF6 can be efficiently isolated in analytically pure form after silica gel chromatography and represent the first examples of unsymmetrically substituted Mo3S44+ clusters that feature mixed terminal ligands. The structural, spectroscopic and electrochemical consequences of the stepwise Cl/dca replacement along the [ 1- 4]PF6 series are also presented. The distinctive UV/Vis and electrochemical features along the [ 1- 4]PF6 series illustrate the ability to fine-tune the physicochemical properties of Mo3S44+ clusters upon stepwise dca incorporation more efficiently than upon complete ligand substitution. [ABSTRACT FROM AUTHOR]