Synthesis, Characterization, and Substitution Chemistry of [Bu4N]2[W6Cl8(OSO2CF3)6]. A Versatile Precursor for Axially Substituted Clusters Containing the {W6Cl8}4+ Core

Weinert, Charles S.; Stern, Charlotte L.; Shriver, Duward F.

doi:10.1021/ic990791+

Cited by 16 publications

(31 citation statements)

References 45 publications

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“…This point is also in good accordance with the assumption that ligand L 2 and L 3 self-arranges in ad ouble-layer morphology.F or instance,bymolecular modeling of L 2 ,one arm of the star-shaped phosphine oxide ligand was found to measure in all-extended conformation around 37 w hereas the rough diameter of the molecule stands for approximately 55 . [15,23] Thee mission properties were investigated in the liquid crystalline state with samples deposited on glass slides,heated to isotropic state and then cooled down slowly to room temperature by using ap olarizing microscope equipped with ah otstage,a n irradiation source (irradiation in the 380-420 nm range), and aCCD spectrophotometer.Itwas found that title clustomesogens,exhibit broad emission ranged from 550 up to 900 nm, with approx. 5-42.8 ) are in fact slightly shorter than the one of corresponding ligand L 2 (45.3 ).…”

Section: Methodsmentioning

confidence: 99%

“…[15] This information could be interpreted by the existence of two competing factors:t he non-equivalence of the six apical ligands due to structural conformation and ap ossible exchange between apical ligands and outer counteranions in solution. This is in stark contrast to the previously reported NMR data for hexa-substituted Mo 6 and W 6 clusters with triphenylphosphine ligands for which only one signal in the 31 PNMR spectrum was recorded.…”

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confidence: 99%

“…Further,t he monitoring by 31 PNMR spectroscopy of the addition of an excess of phosphine oxide L 4 to the solution of MoL 4 led to the collapse of the multiplet signal into two singlets and to the increase of the free ligand signal intensity thus evidencing the ligand exchange ( Figure S13). [15] Thepurity of all compounds was assessed by elemental analysis.T he IR spectra of hexa-substituted Mo 6 and W 6 clusters show several shoulders in the 1100-1200 cm À1 range assigned to the CF 3 SO 3 À ion together with am edium intensity absorption band in the 1000-1100 cm À1 range due to P = Ov ibration ( Figures S19-S22). Them esogenic phosphine oxides L 1-3 were prepared in moderate to good yield in astraightforward manner by the reaction of tris(4-hydroxyphenyl)phosphine oxide with corresponding bromide derivatives.…”

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From Mesomorphic Phosphine Oxide to Clustomesogens Containing Molybdenum and Tungsten Octahedral Cluster Cores

et al. 2015

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New clustomesogens (i.e., metal atom clusters containing liquid crystalline (LC) materials) have been obtained by grafting neutral cyanobiphenyl (CB)-or cholesteryl-containing tailor-made dendritic mesomorphic triphenylphosphine oxide ligands on luminescent (M 6 Cl i 8 ) 4+ octahedral cluster cores (M = Mo,W). The LC properties were studied by ac ombination of polarizing optical microscopy( POM), differential scanning calorimetry (DSC), and X-ray powder diffraction analyses.While the organic ligands showed various mesophase types ranging from nematic, SmA columnar (SmA Col ), SmA, and SmC phases,i tt urned out that the corresponding clustomesogens formed layered phases (SmA) over aw ide range of temperatures that depend on the nature and density of mesogenic groups employed. Intrinsic luminescence properties of the cluster precursors are preserved over the entire range of LC phase existence.Liquid crystals are self-assembling molecular materials that have found various applications ranging from the manufacturing of liquid crystal display (LCD) to different molecular sensors and detectors,o ptical switches,s patial light modulator, etc.,b ased on their unique features to retain ah igh degree of mobility besides long or short-range ordering in the fluid phase that give rise to anisotropy-related optical, electrical, and magnetic properties. [1] On the other hand, metal atom clusters are versatile building blocks for the design of hybrid nanomaterials with potential applications, for instance,inthe fields of lighting,displays,and biolabeling technologies. [2] Association of organic mesogenic moieties with octahedral metallic cluster complexes led to anew family of liquid crystals,n amely the clustomesogens,w hich exhibit interesting photoluminescence properties in the red-nearinfrared region due to the cluster core. [3] In the light of recent findings,q uantum yields of nanometer-sized octahedral clusters can reach values above 60 %. [4] Thea ffordable costs and preparation methods as well as thermal stability,the ease of handling and processing make them very appealing materials to be used in different applications based on emission properties (LED,lighting displays,etc.). Combining such nanoobjects with liquid-crystalline ordering is achallenging task [5] and so far,s everal strategies based on covalent binding or ionic self-assembly (ISA) were successfully employed to induce liquid crystalline (LC) properties in systems containing bulky entities,s uch as fullerene [6] and polyoxometalates. [7,8] On the other hand, phosphine or phosphine oxide ligands were scarcely used in the design of liquid-crystalline materials,mainly due to their inappropriate geometry concerning the molecular requirements to generate mesomorphic behavior. [9] Moreover,e ven if they are widely used as ligands in coordination chemistry only few examples of phosphine-oxide-containing metallomesogens (metal-containing liquid crystals) are known. [10] Generally,o nly less bulky phosphines,s uch as trialkylphosphine (alkyl = methyl, ethyl, prop...

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From Mesomorphic Phosphine Oxide to Clustomesogens Containing Molybdenum and Tungsten Octahedral Cluster Cores

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“…This is in stark contrast to the previously reported NMR data for hexa-substituted Mo 6 and W 6 clusters with triphenylphosphine ligands for which only one signal in the 31 PNMR spectrum was recorded. [15] This information could be interpreted by the existence of two competing factors:t he non-equivalence of the six apical ligands due to structural conformation and ap ossible exchange between apical ligands and outer counteranions in solution. These findings determined us to have ac loser look at the X-ray crystal structure of compounds MoL 4 and WL 4 revealing that the six MÀOb onds are not equivalent (Table S2 in SI).…”

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confidence: 99%

“…[11,16] The covalent hexa-functionalization of the Mo 6 and W 6 metallic clusters has been achieved by al igand-exchange reaction between the [M 6 Cl 8 (CF 3 SO 3 ) 6 ] 2À cluster unit with as light excess of mesogenic phosphine oxide ligand in dichloromethane at room temperature (Scheme 1). [15] Thepurity of all compounds was assessed by elemental analysis.T he IR spectra of hexa-substituted Mo 6 and W 6 clusters show several shoulders in the 1100-1200 cm À1 range assigned to the CF 3 SO 3 À ion together with am edium intensity absorption band in the 1000-1100 cm À1 range due to P = Ov ibration (Figures S19-S22). The 31 PNMR spectra contain the same features as those found for non-mesogenic Mo 6 and W 6 clusters MoL 4 and WL 4 ,f or example,amultiplet around 55 ppm and abroad signal centered around 30 ppm, suggesting as imilar behavior in solution with six apical ligands around the cluster unit ( Figure S8).…”

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From Mesomorphic Phosphine Oxide to Clustomesogens Containing Molybdenum and Tungsten Octahedral Cluster Cores

et al. 2015

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Octa(μ3-selenido)hexarhenium(III) Complexes Containing Axial Monodentate Diphosphine or Diphosphine-Monoxide Ligands

et al. 2001

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A series of the octahedral hexarhenium(III) complexes containing a variable number of diphosphine (diphos) or diphosphine-monoxide (diphosO) ligands have been prepared by the substitution of the diphosphine Ph2P(CH2)nPPh2 (n = 1 to 5) for the iodide ions in the parent octahedral hexarhenium cluster compound [Re6Se8I6]3-. The diphosphine Ph2P-(CH2)nPPh2 ligands adopt an eta1-bonding mode with the Re6(mu3-Se)8 core, and the P donor atom in the pendant arm is noncoordinated and oxygenated in most cases. The series of new hexarhenium(III) complexes have been well-defined by 1H, 13C, and 31P NMR spectroscopic and FAB-MS data. Four compounds among the series were characterized by X-ray structural determination. Geometrical isomers were identified by NMR spectroscopy as well as by the structural determinations. The apical ligand substitution induces significant change in the redox potentials and the photophysical properties of the Re6(mu3-Se), core. The E1/2 value of the reversible process ReIII6/ReIII5ReIV becomes more positive with the increasing number of the coordinated P donors. The phosphine-substituted hexarhenium(III) derivatives are highly luminescent, with microsecond scale emissive lifetime at ambient temperature, and the fully substituted derivatives with the formula [Re6Se8-(eta1-diphosO)6]2+ display the strongest luminescence with the longest emission lifetimes.

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Synthesis, Characterization, and Substitution Chemistry of [Bu₄N]₂[W₆Cl₈(OSO₂CF₃)₆]. A Versatile Precursor for Axially Substituted Clusters Containing the {W₆Cl₈}⁴⁺ Core

Cited by 16 publications

References 45 publications

From Mesomorphic Phosphine Oxide to Clustomesogens Containing Molybdenum and Tungsten Octahedral Cluster Cores

From Mesomorphic Phosphine Oxide to Clustomesogens Containing Molybdenum and Tungsten Octahedral Cluster Cores

From Mesomorphic Phosphine Oxide to Clustomesogens Containing Molybdenum and Tungsten Octahedral Cluster Cores

Octa(μ3-selenido)hexarhenium(III) Complexes Containing Axial Monodentate Diphosphine or Diphosphine-Monoxide Ligands

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