Structure and solution behaviour of rhodium(I) Vaska-type complexes for correlation of steric and electronic properties of tertiary phosphine ligands

Roodt, Andreas; Otto, Stefanus; Steyl, Gideon

doi:10.1016/s0010-8545(03)00069-9

Cited by 146 publications

(135 citation statements)

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“…Similar average metal-oxido distances have been noted on several occasions in past studies (Allen, 2002;Davies and Jones, 2005;Peric, Brnicevic and Juric, 2009;Calderazzo and Englert, 1998;Roodt, Otto and Steyl, 2003;Schutte, Roodt and Visser, 2012). This phenomenon can probably be attributed to the near-identical covalent radii of both Ta and Nb.…”

supporting

confidence: 85%

Exploring differences in various Nb(V)- and Ta(V) tropolonato complexes by a solid-state structural comparison study

Koen

Roodt

Visser

2016

J. South. Afr. Inst. Min. Metall.

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Niobium and tantalum are chemical 'twins' of the vanadium triad of the periodic table and are notoriously difficult to separate from one another and from their naturally occurring ores, due to their near-identical physical and chemical properties (Agulyansky, 2004). This similarity in behaviour has been ascribed mainly to the lanthanide contraction of the elements and also their comparable ionization energies (Hubert-Pfalzgraf, Postel and Reiss, 1987). Although the separation methods currently applied on an industrial scale, such as solvent extraction and chlorination, have been successful, these techniques remain very laborious, expensive and evolve significant chemical waste (Bose and Gupta, 2001). Accordingly, there is substantial scope for improvements in the metallurgical methods of purification of niobium and separation from tantalum.The key to the effective and simplified separation of these elements could possibly be found in the differences in the chemical properties of two similar organic chelated moieties of these metals. Interestingly, a detailed literature review revealed a considerable shortage of knowledge in relation to the chelation behaviour of tantalum and niobium with different organic bidentate or multidentate ligands (Allen, 2002). In fact, only a single study by Muetteries and Wright (1965) The solution-state investigation of the formation of these compounds was quite thorough, but not much attention was given to the solid-state characteristics of the compounds (Muetteries and Wright, 1965). With this in mind, a detailed, low-temperature crystallographic investigation of the coordi- tropolone, stability, geometry, tantalum, niobium.

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supporting

confidence: 85%

Exploring differences in various Nb(V)- and Ta(V) tropolonato complexes by a solid-state structural comparison study

Koen

Roodt

Visser

2016

J. South. Afr. Inst. Min. Metall.

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“…The products were convincingly characterized to confirm the structure and purity, and these data compare well to the reported values. [10][11][12] A high quality, low temperature X-ray diffraction study was also performed on a sample of 18 grown from a CH 2 472,571,693,727,999,1024,1077,1158,1183,1305,1434,1482,150,1955 455,473,485,522,563,574,696,743,752,776,789,848,928,997,1031,1048,1230,1383,1439,1478,1606 458, 469, 521, 573, 643, 691, 741, 895, 997, 1044, 1092, 1145, 1185, 1204, 1359, 1377, 1440, 1568, 1868, 4, -110.9, -113.4, -120.6, -127.6, -134.3, -136.9, -141.4; FT-IR (ν, cm -1 ): 482,573,651,695,736,746,996,1033,1080,1143,1183,1264,1352,…”

Section: Synthesis Of 13mentioning

confidence: 99%

α-Cationic Arsines: Synthesis, Structure, Reactivity, and Applications

et al. 2016

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A series of structurally differentiated cationic arsines containing imidazolium, cyclopropenium, formamidinium, and pyridinium substituents have been synthesized through short and scalable routes. Evaluation of the donor properties of these compounds by IR spectroscopy and DFT calculations reveals similar σ-electron-releasing abilities for all of them; however, their π-acceptor properties are strongly influenced by the nature of the positively charged group. We describe the coordination chemistry of the newly prepared α-cationic arsines toward different metal centers and their reactivity in the presence of strong oxidants to afford cationic As(V) species. Their unique electronic properties have been exploited in Pt(II) catalysis to develop a new catalyst with remarkable activity in the cycloisomerization of enynes to trisubstituted cyclopropanes. To the best of our knowledge, this is the first report on the use of α-cationic arsine ligands in catalysis

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“…This shows the versatility of this ligand class, and conversely the need for careful elucidation of the reaction products. We initially chose this ligand type in our research towards bidentate systems [3][4][5], but we were amazed about its rich coordination chemistry, that depends heavily on the reaction conditions and transition metal precursor [6]. Also, the use of the 1,5-cyclooctadiene ligand gives important information on the influence of the other ligands [7,8].…”

Section: Discussionmentioning

confidence: 99%

Crystal structure of (N-benzoyl-N'-(2,4,6-trimethylphenyl)thiourea-κS)chlorido(η4-cycloocta-1,5-diene) rhodium(I), C25H30ClN2ORhS

Warsink

Roodt

Venter

et al. 2013

Zeitschrift Für Kristallographie - New Crystal Structures

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Source of materialTo an acetone (2 mL) solution of [Rh(h 4 -1,5-cyclooctadiene)Cl] 2 (20 mg, 0.0405 mmol), N-benzoyl-N'-(2,4,6-trimethylphenyl)-thiourea [9] (20.8 mg, 0.0811 mmol) was added. The reaction mixture was vigorously stirred until all of the reagents were fully dissolved. The acetone was then allowed to evaporate slowly to obtain the product as an orange crystalline solid. DiscussionIn the title compound, the thiourea ligand shows monodentate coordination through its sulfur-atom, analogous with a structure earlier reported by us. All metal-ligand bond lengths are within expected ranges [1]. However, depending on the substituents of the ligand, we have also observed bidentate coordination [2]. This shows the versatility of this ligand class, and conversely the need for careful elucidation of the reaction products. We initially chose this ligand type in our research towards bidentate systems [3-5], but we were amazed about its rich coordination chemistry, that depends heavily on the reaction conditions and transition metal precursor [6]. Also, the use of the 1,5-cyclooctadiene ligand gives important information on the influence of the other ligands [7,8]. In the title structure, the rhodium adopts a slightly distorted square planar geometry. The structure is intramolecularly stabilized by hydrogen bonds, of which that between N1 and Cl1 stabilizes the coordination sphere (2.38(3) Å), and the one between N2 and O1 (2.06(3) Å) stabilizes the overall ligand conformation. Additionally, there is an intermolecular hydrogen bond interaction between the amide moieties (N2···O1' = 2.50(3) Å; ' = y-x, y-y, -z), creating dimeric structures.

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Structure and solution behaviour of rhodium(I) Vaska-type complexes for correlation of steric and electronic properties of tertiary phosphine ligands

Cited by 146 publications

References 53 publications

Exploring differences in various Nb(V)- and Ta(V) tropolonato complexes by a solid-state structural comparison study

Exploring differences in various Nb(V)- and Ta(V) tropolonato complexes by a solid-state structural comparison study

α-Cationic Arsines: Synthesis, Structure, Reactivity, and Applications

Crystal structure of (N-benzoyl-N'-(2,4,6-trimethylphenyl)thiourea-κS)chlorido(η4-cycloocta-1,5-diene) rhodium(I), C25H30ClN2ORhS

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