Synthesis and characterization of binuclear tantalum hydride complexes

Scioly, Anthony J.; Luetkens, Melvin L.; Wilson, Roxy B.; Huffman, John C.; Sattelberger, Alfred P.

doi:10.1016/s0277-5387(00)86882-5

Cited by 27 publications

(36 citation statements)

References 35 publications

(3 reference statements)

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“…For example, consider the following Ta-Ta separations: BaTa 0.8 Se 3 , 3.015 Å; 3 BaTaS 3 , 2.872(3) Å; 10,11 Ta 6 S, 2.644(5) Å; 48 [(cb)(PMe 2 Ph) 2 (H)Ta(µ-H) 4 Ta(H)(PMe 2 Ph) 2 (cb)] (cb ) carbazole), 2.536(1) Å; 49 and Ta 2 Cl 4 (PMe 3 ) 4 H 4 , 2.511(2) Å. 50 In addition to this random distribution along a given chain, there are ordered ways that lead to a centrosymmetric structure. In one, pairs of Ta atoms could cluster together (the "pairing distortion"), much as in materials that have undergone a Peierls distortion.…”

Section: Resultsmentioning

confidence: 99%

Ta⁵⁺ Displacements in CsTaQ₃ (Q = S, Se, and Te): New One-Dimensional Materials with the BaVS₃ Structure

1997

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The new compounds CsTaQ 3 (Q ) S, Se, and Te) have been synthesized through stoichiometric reactions of the elements with Cs 2 Q n reactive fluxes at 923 K. Their crystal structures have been determined by single-crystal X-ray methods. CsTaQ 3 crystallize in the hexagonal space group D 6h 4 -P6 3 /mmc with two formula units per cell. Crystal data: CsTaS 3 , a ) 7.266(2) Å, c ) 5.961(2) Å, V ) 272.55(10) Å 3 (T038. The compounds adopt the BaVS 3 structure type and feature ∞ 1 [TaQ 3 -] chains of face-sharing octahedra. The Ta 5+ centers are displaced from the centers of the Q 6 octahedra along the direction of the chains in a centrosymmetric fashion. Geometrical considerations and band structure calculations at the extended Hu ¨ckel and density functional (DFT) levels of theory suggest that the most likely distortion pattern is the one with all Ta 5+ centers displaced in the same direction within a given chain. A second-order Jahn-Teller effect is responsible for this distortion. Very weak interchain communication would result in a centrosymmetric structure. The chains are separated by 12-coordinate Cs + cations. CsTaSe 3 is an insulator. CsTaTe 3 shows semiconducting behavior and is diamagnetic or weakly paramagnetic. Differential scanning calorimetry (DSC) and high-temperature powder diffraction data indicate that CsTaTe 3 undergoes a phase transition at ≈493 K. Experimental and Theoretical SectionSyntheses. CsTaQ3 (Q ) S, Se, and Te) were synthesized by the reactive-flux method. 20 Elemental S (Johnson Matthey, 99.999%), Se (Aldrich, 99.5%), and Te (Aldrich, 99.8%) were stoichiometrically added to Cs (Aldrich, 99.5%) dissolved in liquid NH 3 at 194 K to form Cs 2S5, Cs2Se3, and Cs2Te3, respectively. Cs2Qn was then ground together with powders of Ta (Aldrich, 99.9%) and Q in a 1:2:1 ratio for Q ) S and a 1:2:3 ratio for Q ) Se and Te and sealed under high vacuum in fused-silica tubes. The charged tubes were heated at 923 K for 6 d, then cooled to room temperature at 4 K/h. Black

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Section: Resultsmentioning

confidence: 99%

Ta⁵⁺ Displacements in CsTaQ₃ (Q = S, Se, and Te): New One-Dimensional Materials with the BaVS₃ Structure

1997

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“…ELF is directly related to the electron pair probability density, and its graphical representation contributes to the understanding of electron localization/delocalization and consequently to the degree of metal−metal interaction. Two-dimensional electron density distribution plots are depicted in Figure 10 for 23 , as well as for the parent compound 6 ( d [Ta−Ta] = 2.926 Å) and [Ta 2 (PMe 3 ) 4 Cl 4 (μ-H) 2 ] [ 93 ], where a short Ta−Ta bond length is observed (2.545 Å), for comparison. A high delocalization of electrons between the metals is observed in 23 and 6 , as generally computed for complexes with weak M−M interactions [ 94 ].…”

Section: Oblatoarachno -M 2 mentioning

confidence: 99%

Polyhedral [M2B5] Metallaborane Clusters and Derivatives: An Overview of Their Structural Features and Chemical Bonding

2020

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A large number of metallaborane clusters and their derivatives with various structural arrangements are known. Among them, M2B5 clusters and derivatives constitute a significant class. Transition metals present in these species span from group 4 to group 7. Their structure can vary from oblatonido, oblatoarachno, to arachno type open structures. Many of these clusters appear to be hypoelectronic and are often considered as ‘rule breakers’ with respect to the classical Wade–Mingos electron counting rules. This is due to their unique highly oblate (flattened) deltahedral structures featuring a cross-cluster M−M interaction. Many theoretical calculations were performed to elucidate their electronic structure and chemical bonding properties. In this review, the synthesis, structure, and electronic aspects of the transition metal M2B5 clusters known in the literature are discussed. The chosen examples illustrate how, in synergy with experiments, computational results can provide additional valuable information to better understand the electronic properties and electronic requirements which govern their architecture and thermodynamic stability.

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“…47% smaller with a value of 0.08. These values may be compared to the metalmetal indices computed for the tantalum compounds (Cp*Ta) 2 B 5 H 11 (Wiberg index = 0.71) 38 and Ta 2 (PMe 3 ) 4 Cl 4 -(µ-H) 2 (Wiberg index = 2.00) 39 that serve as benchmark systems that contain a formal Ta-Ta and TavTa bond, respectively. 3 is the first structurally characterized tantalum compound with an all-nitrogen coordination sphere that contains imido, amido, and azido ligands.…”

Section: ð3þmentioning

confidence: 99%

New azido-substituted tantalum compounds: syntheses and DFT examination of nitrogen-rich mono-, di-, and trinuclear tantalum(v) compounds

2014

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The syntheses of new tantalum compounds containing an ancillary azido ligand(s) are described. The tantalum compound with the composition Ta(NMe2)4(N3) has been synthesized in high yield from the reaction of TaCl(NMe2)4 with NaN3 in THF. The solid-state structure reveals a dimeric architecture based on Ta2(NMe2)8(μ-N3)2 (), where the eight-membered dimetallocyclic ring possesses a chair-like conformation with bridging azido ligands binding the two Ta(NMe2)4 moieties. Solution molecular weight measurements and electronic structure calculations predict to exist as a monomer at room temperature. reacts with the formamidine (i)PrNC(H)NH(i)Pr to furnish fac-Ta(NMe2)3(η(1)-N3)[(i)PrNC(H)N(i)Pr] () and Me2NH; compound has been characterized by IR and (1)H NMR spectroscopy and X-ray diffraction analysis. Treatment of with p-toluidine affords the trinuclear compound Ta3(NMe2)5(μ-NMe2)(μ-NC6H4Me-4)2(NC6H4Me-4)(μ-N3)2(η(1)-N3) (). Compound contains three non-bonded tantalum atoms that are ligated by edge-bridging imido, amido, and azido ligands. The molecular structure of has been determined by X-ray crystallography, and the unprecedented presence of terminal and bridging imido, amido, and azido ligands in a single tantalum compound confirmed. The bonding in has been examined by DFT, and these data are discussed relative to the crystallographic structure. Compounds represent the first structurally characterized examples of heteroleptic tantalum compounds that possess an all-nitrogen coordination sphere with at least one azido ligand.

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Synthesis and characterization of binuclear tantalum hydride complexes

Abstract: Reduction of the quadruply-bridged

Cited by 27 publications

References 35 publications

Ta⁵⁺ Displacements in CsTaQ₃ (Q = S, Se, and Te): New One-Dimensional Materials with the BaVS₃ Structure

Ta⁵⁺ Displacements in CsTaQ₃ (Q = S, Se, and Te): New One-Dimensional Materials with the BaVS₃ Structure

Polyhedral [M2B5] Metallaborane Clusters and Derivatives: An Overview of Their Structural Features and Chemical Bonding

New azido-substituted tantalum compounds: syntheses and DFT examination of nitrogen-rich mono-, di-, and trinuclear tantalum(v) compounds

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Synthesis and characterization of binuclear tantalum hydride complexes

Abstract: Reduction of the quadruply-bridged

Cited by 27 publications

References 35 publications

Ta5+ Displacements in CsTaQ3 (Q = S, Se, and Te): New One-Dimensional Materials with the BaVS3 Structure

Ta5+ Displacements in CsTaQ3 (Q = S, Se, and Te): New One-Dimensional Materials with the BaVS3 Structure

Polyhedral [M2B5] Metallaborane Clusters and Derivatives: An Overview of Their Structural Features and Chemical Bonding

New azido-substituted tantalum compounds: syntheses and DFT examination of nitrogen-rich mono-, di-, and trinuclear tantalum(v) compounds

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Ta⁵⁺ Displacements in CsTaQ₃ (Q = S, Se, and Te): New One-Dimensional Materials with the BaVS₃ Structure

Ta⁵⁺ Displacements in CsTaQ₃ (Q = S, Se, and Te): New One-Dimensional Materials with the BaVS₃ Structure