Exploring the Lewis basicity of the metalloligand [Pt₂(μ-Se)₂(PPh₃)₄] on metal substrates by electrospray mass spectrometry. Synthesis, characterization and structural studies of new platinum selenido phosphine complexes containing the {Pt₂Se₂} core

Electrospray Mass Spectrometry (ESMS) has been used as a tool to probe the reactivity of the metalloligand [Pt₂(μ-Se)₂(PPh₃)₄] with metal substrates, which lead to the formation of charged coordination complexes via loss of halides or other labile ligands. Among the numerous metal substrates used in the displacement reactions are Au(anpy)Cl₂ (anpy = cyclometallated 2-anilinopyridyl), HgPhCl and Pb(NO₃)₂. Acid titration on the Lewis basic metalloligand leads to the identification and isolation of the doubly-protonated species, [Pt₂(μ-SeH)₂(PPh₃)₄]²⁺, whose sulfide analogue cannot be isolated. A three-step strategy is employed in the use of ESMS as a probe: (i) preliminary screening of the metalloligand with an array of acidic main group and transition group metal compounds, (ii) identification of potentially stable and isolable products formed in situ based on ion distribution and simulated isotope patterns and (iii) promising reactions are repeated on a laboratory scale, and target products are isolated and characterized. X-Ray diffraction studies have been performed on single crystals of [Pt₂(μ-SeH)₂(PPh₃)₄][ClO₄]₂, [Pt₂(μ₃-Se)₂(PPh₃)₄(CdCl₂)] and {Pt₂(μ₃-Se)₂(PPh₃)₄[Pb(NO₃)]}{NO₃}. These results suggested that in general a parallel chemistry can be developed on the intermetallic selenides as on the sulfides. However, there are chemical and structural differences which are highlighted in this paper

Ligand exchange reactions of [Re₂(μ-OR)₃(CO)₆]⁻(R = H, Me) with sulfur, selenium, phosphorus and nitrogen donor ligands, investigated by electrospray mass spectrometry

Negative-ion electrospray mass spectrometry has been used to investigate the reactions of the dinuclear rhenium aggregates [Re₂(μ-OH)₃(CO)₆]⁻ 1 and [Re₂(μ-OMe)₃(CO)₆]⁻ 2 with a range of thiols, benzeneselenol, and some other sulfur-, phosphorus- and nitrogen-based ligands. Typically up to three of the hydroxo ligands are replaced by simple thiolates, giving the series of species [Re₂(OH)₂(SR)(CO)₆]⁻, [Re₂(OH)(SR)₂(CO)₆]⁻, and [Re₂(SR)₃(CO)₆]⁻. Similarly, reaction of 1 with H₂S gives the species [Re₂(μ-SH)₃(CO)₆]⁻, which undergoes an analogous fragmentation process to [Re₂(μ-OH)₃(CO)₆]⁻, at high cone voltages, by loss of H₂S and formation of [Re₂(S)(SH)(CO)₆]⁻. With ligands which are good chelating agents (such as dithiocarbamates R₂NCS₂⁻, and thiosalicylic acid, HSC₆H₄CO₂H) initial substitution of one or two OH groups readily occurs, but on standing the dimer is cleaved giving [Re(S₂CNR₂)₂(CO)₃]⁻ and [Re(SC₆H₄CO₂)(CO)₃]⁻. The different reactivities of the dithiol reagents benzene-1,2- and benzene-1,4-dimethanethiol towards 1 are also described. Complex 1 also reacts with aniline, and with primary (but not secondary) amides RC(O)NH₂, giving monosubstituted species [Re₂(OH)₂(NHPh)(CO)₆]⁻ and [Re₂(OH)₂{NHC(O)R}(CO)₆]⁻ respectively. The reactions with adenine and thymine, and with the inorganic anions thiocyanate and thiosulfate, are also described

Mass spectrometry-directed synthesis of early–late sulfide-bridged heterobimetallic complexes from the metalloligand [Pt₂(PPh₃)₄(μ-S)₂] and oxo compounds of vanadium(V), molybdenum(VI) and uranium(VI)

The metalloligand [Pt₂(PPh₃)₄(μ-S)₂] has been found to react with the transition metal oxo compounds, ammonium metavanadate, sodium molybdate, and the actinide complex uranyl nitrate to give sulfide-bridged heterobimetallic complexes [Pt₂(PPh₃)₄(μ₃-S)₂VO(OMe)₂]⁺, [Pt₂(PPh₃)₄(μ₃-S)₂MoO₂(OMe)]⁺, and [Pt₂(PPh₃)₄(μ₃-S)₂UO₂( ₂-NO₃)₂], respectively. Electrospray mass spectrometry (ESMS) was used to probe the reactivity of [Pt₂(PPh₃)₄(μ-S)₂] and thus identify likely targets for isolation and characterization. ESMS has also been used to investigate fragmentation pathways of the new species. No bimetallic species were detected with hydrated La(NO₃)₃or Th(NO₃)₄, or with the lanthanide shift reagent Eu(fod)₃ (fod = 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate). X-Ray crystal structure determinations have been carried out on [Pt₂(PPh₃)₄(μ₃-S)₂VO(OMe)₂]⁺, 2, (as its hexafluorophosphate salt) and [Pt₂(PPh₃)₄(μ₃-S)₂UO₂( ₂-NO₃)₂], 4. The vanadium atom of 2 has a distorted square pyramidal geometry, while the uranium in 4 has the expected linear dioxo coordination geometry, with two bidentate nitrates and a bidentate {Pt₂S₂} moiety

Form of Citation of Japanese Legal Materials

The chief purpose of a citation, aside from furnishing assurance of scholarly discipline, is to make the author\u27s sources available to others. Citation style rules should strive to do this uniformly, briefly, and clearly. For the sake of uniformity in citing Japanese language sources it is suggested that writers use the manual published by the Harvard Law Review Association, A Uniform System of Citation (11th ed. 1967), whenever its rules can be directly applied, or whenever they can be readily adapted to citation of Japanese sources. New rules are suggested below only for those relatively few instances where they are required by the peculiarities of the Japanese materials, language, or legal system

Form of Citation of Japanese Legal Materials

The chief purpose of a citation, aside from furnishing assurance of scholarly discipline, is to make the author\u27s sources available to others. Citation style rules should strive to do this uniformly, briefly, and clearly. For the sake of uniformity in citing Japanese language sources it is suggested that writers use the manual published by the Harvard Law Review Association, A Uniform System of Citation (11th ed. 1967), whenever its rules can be directly applied, or whenever they can be readily adapted to citation of Japanese sources. New rules are suggested below only for those relatively few instances where they are required by the peculiarities of the Japanese materials, language, or legal system

A rapid screening, “combinatorial-type” survey of the metalloligand chemistry of Pt₂(PPh₃)₄(μ-S)₂ using electrospray mass spectrometry

Electrospray mass spectrometry is a rapid and powerful technique for a combinatorial-like survey of the chemistry of the metalloligand Pt₂(PPh₃)₄(μ-S)₂, leading to the successful isolation and crystallographic characterisation of the novel protonated species Pt₂(PPh₃)₄(μ-S)(μ-SH) together with a range of metallated derivatives