Synthesis and X-ray crystal structures of alkaline-earth metallocenes with pendant substituents

Hays, Melanie L.; Hanusa, Timothy P.; Nile, Terence A.

doi:10.1016/0022-328x(95)06015-o

Cited by 44 publications

(33 citation statements)

References 28 publications

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“…This is a wellknown problem in alkaline earth metal chemistry. [25] In addition, thiolates and selenolates tend to give notoriously unreliable elemental analyses due to the formation of non-volatile metal selenolates.…”

Section: Methodsmentioning

confidence: 99%

Barium Thiolates and Selenolates: Syntheses and Structural Principles

Ruhlandt‐Senge

Englich

2000

Chem. Eur. J.

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The synthesis and structural characterization of a family of barium thiolates and selenolates is described. The thiolates were synthesized by metallation of thiols, the selenolates by reductive insertion of the metal into the selenium-selenium bond of diorganodiselenides. Both reaction sequences were carried out by using barium metal dissolved in ammonia; this afforded barium thiolates and selenolates in good yield and purity. The structural principles displayed in the target compounds span a wide range of solid-state formulations, including monomeric and dimeric species, and separated ion triples, namely [Ba(thf)4(SMes*)2] (1; Mes* = 2,4,6-tBU3C6H2), [Ba(thf)4(SeMes*)2] (2), [Ba([18]crown-6)(hmpa)2][(SeMes*)2] (3), the dimeric [(Ba(py)3(thf)(SeTrip)2)2] (4; py = pyridine, Trip = 2,4.6-iPr3C6H2), and [Ba([18]crown-6)(SeTrip)2] (5). The full range of association modes is completed by [Ba([18]crown-6)(hmpa)SMes*][SMes*] (6) communicated earlier by this group. In the solid state, this compound displays an intermediate ion coordination mode: one anion is bound to the metal, while the second one is unassociated. Together these compounds provide structural information about all three different association modes for alkaline earth metal derivatives. This collection of structural data allows important conclusions about the influence of solvation and ligation on structural trends.

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Section: Methodsmentioning

confidence: 99%

Barium Thiolates and Selenolates: Syntheses and Structural Principles

Ruhlandt‐Senge

Englich

2000

Chem. Eur. J.

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“…This is a well-known problem in alkaline earth metal chemistry. [34] Procedure A, Transamination: In a typical experiment, a Schlenk tube was charged with one equivalent of [Ca{N(SiMe 3 ) 2 } 2 (THF) 2 ] (typically 3.6 mmol), dissolved in 40 mL of donor solvent (THF, pyridine or DME) and stirred at low temperature for half an hour. To this, a solution of two equivalents of 2-DMAMP in 20 mL of the same solvent was added dropwise with vigorous stirring.…”

Section: Methodsmentioning

confidence: 99%

Synthesis, Structures and Characterization of the Calcium Pyrrolates [Ca{(2‐(dimethylaminomethyl)pyrrolyl}₂ donor_n] (donor = THF and pyridine, n = 2; DME and TMEDA, n = 1) as Potential Precursors for Solid‐State Applications

Vargas

Ruhlandt‐Senge

2003

Eur J Inorg Chem

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The synthesis and characterization of novel alkaline earth metal pyrrolyl derivatives is described. The target molecules were synthesized using transamination and metallation protocols, involving either the treatment of calcium bis[bis(trimethylsilyl)]amide with two equivalents of 2‐(dimethylaminomethyl)pyrrole (2‐DMAMP) or the reaction of elemental calcium with two equivalents of 2‐DMAMP. Different donors, namely THF, pyridine (py), DME (dimethoxyethane), and TMEDA (N,N,N′,N′‐tetramethylethylenediamine) were utilized to study their influence on the structural chemistry of the target compounds. In order to compare the influence of the metal coordination on the pyrrole ligand, we included the crystal structure of the free 2‐DMAMP ligand. All new compounds were characterized using 1H, 13C NMR and IR spectroscopy in addition to X‐ray crystallography. Crystal data with Mo‐Kα radiation (λ = 0.71073 Å) are as follows: 1: [Ca(2‐DMAMP)2(THF)2], a = 15.440(2) Å, b = 14.992(2) Å, c = 10.175(1) Å, β = 94.9(3)°,V= 2346.6(6) Å3, Z = 4, monoclinic, space group P21/c, R1(all data) = 0.0981; 2: [Ca(2‐DMAMP)2(py)2], a = 9.168(6) Å, b = 10.418(7) Å, c = 13.329(8) Å, α = 85.9(1)°, β = 72.9(1)°, γ = 86.2(1)°, V = 1212.2(1) Å3, Z = 2, triclinic, space group P$\bar 1$ , R1 (all data) = 0.0711; 3: [Ca(2‐DMAMP)2(DME)], a = 10.814(1) Å, b = 12.907(1) Å, c = 15.170(1) Å, V = 2117.3(3) Å3, Z = 4, orthorhombic, space group P212121, R1 (all data) = 0.0729; 4: [Ca(2‐DMAMP)2(TMEDA)], a = 9.403(6) Å, b = 15.810(1) Å, c = 15.417(1) Å, V = 2292.0(3) Å3, Z = 4, orthorhombic, space group Pbcn, R1 (all data) = 0.0997; 5: 2‐DMAMP, a = 10.8820(7) Å, b = 15.2186(10) Å, c = 9.7578(6) Å, β = 109.736(2)°,V = 1521.05(17) Å3, Z = 2, monoclinic, space group Cc, R1 (all data) = 0.0382. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

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“…As shown in Scheme , cyclopentadienyl ligands bearing donor‐functionalized pendants, such as amine and pyridyl ( 1 , 2 ),8a,b methoxy ( 3 , 4 , 5 ),8b–d and alkenyl ( 6 )8e groups, have been successfully applied for the synthesis of heavier alkaline earth (Ca, Sr, Ba) complexes. Intramolecular coordination of the pendant groups to the metal centers has been confirmed by single‐crystal X‐ray structural analysis 8b,d,e. However, although some progress has been made by using the above‐mentioned ligands, diversity among the cyclopentadienyl ligands and their pendant groups remains very limited.…”

Section: Introductionmentioning

confidence: 99%

Ultrasonic oscillations effect on rheological and processing properties of metallocene‐catalyzed linear low density polyethylene

Guo

Chen

et al. 2003

J of Applied Polymer Sci

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ABSTRACT:The effects of ultrasonic oscillations and die materials on die pressure, productivity of extrusion, melt viscosity of metallocene-catalyzed linear low density polyethylene (mLLDPE), as well as their mechanism were studied in a special ultrasonic oscillations extrusion system developed in our lab. Die materials used in our experiment included steel, brass, and polytetrafluoroethylene (PTFE) . The experimental results showed that ultrasonic oscillations as well as die materials have great influence on the rheological and processing behavior of mLLDPE. Ultrasonic oscillations can greatly increase the productivity of mLLDPE melt extruded through different dies, and can decrease the die pressure and the melt viscosity of mLLDPE. Compared with steel or brass die, mLLDPE melt extruded through PTFE die is more sensitive to ultrasonic oscillations. A possible mechanism for the improved processability of mLLDPE is proposed in this article.

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Synthesis and X-ray crystal structures of alkaline-earth metallocenes with pendant substituents

Abstract: Abstract:Deprotonation of [(2-C 5 The complex also has a bent metallocene geometry, with average Ca-C and Ca-O distances are 2.670(6) and 2.407(3) Å respectively; the ring centroid-Ca-ring centroid angle is 136.6°.

Cited by 44 publications

References 28 publications

Barium Thiolates and Selenolates: Syntheses and Structural Principles

Barium Thiolates and Selenolates: Syntheses and Structural Principles

Synthesis, Structures and Characterization of the Calcium Pyrrolates [Ca{(2‐(dimethylaminomethyl)pyrrolyl}₂ donor_n] (donor = THF and pyridine, n = 2; DME and TMEDA, n = 1) as Potential Precursors for Solid‐State Applications

Ultrasonic oscillations effect on rheological and processing properties of metallocene‐catalyzed linear low density polyethylene

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Synthesis and X-ray crystal structures of alkaline-earth metallocenes with pendant substituents

Abstract: Abstract:Deprotonation of [(2-C 5 The complex also has a bent metallocene geometry, with average Ca-C and Ca-O distances are 2.670(6) and 2.407(3) Å respectively; the ring centroid-Ca-ring centroid angle is 136.6°.

Cited by 44 publications

References 28 publications

Barium Thiolates and Selenolates: Syntheses and Structural Principles

Barium Thiolates and Selenolates: Syntheses and Structural Principles

Synthesis, Structures and Characterization of the Calcium Pyrrolates [Ca{(2‐(dimethylaminomethyl)pyrrolyl}2 donorn] (donor = THF and pyridine, n = 2; DME and TMEDA, n = 1) as Potential Precursors for Solid‐State Applications

Ultrasonic oscillations effect on rheological and processing properties of metallocene‐catalyzed linear low density polyethylene

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Synthesis, Structures and Characterization of the Calcium Pyrrolates [Ca{(2‐(dimethylaminomethyl)pyrrolyl}₂ donor_n] (donor = THF and pyridine, n = 2; DME and TMEDA, n = 1) as Potential Precursors for Solid‐State Applications