A Unique Nido Exo-Arachno Equilibrium Involving [(PPh3)2(CO)OsB5H9] and Its Base Adducts:  Crystal and Molecular Structure of [{(PPh3)2(CO)OsB4H7}(BH2·PPh2Me)]

Barton, Lawrence; Bould, Jonathan; Fang, Hong; Hupp, Kevin; Rath, Nigam P.; Gloeckner, C.

doi:10.1021/ja962192x

Cited by 23 publications

(22 citation statements)

References 19 publications

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“…The loss of boron vertices is obviously a key part of the process to give 3a. Clues for the mechanism may derive from the reaction of [(PPh3)2(CO)OsB5H9] with phosphines L, which quantitatively and reversibly afford [(PPh3)2(CO)OsB4H7(BH2L)] in solution 38,39 -here, in the formation of the cluster-bound exopolyhecral {BH2L} moiety, the two-electron ligand L has clearly engendered an extrusion of a boron vertex. In macropolyhedral systems, reaction of PMe2Ph with S2B17H17 results in loss of a boron vertex to give [S2B16H14(PMe2Ph)2] and [S2B16H16(PMe2Ph)]; of these, the latter has some structural similarities to compound 3a.…”

Section: XXmentioning

confidence: 99%

Substitution of the laser borane anti-B₁₈H₂₂ with pyridine: a structural and photophysical study of some unusually structured macropolyhedral boron hydrides

et al. 2018

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Reaction of anti-BH1 with pyridine in neutral solvents gives sparingly soluble BH-3',8'-Py3a as the major product (ca. 53%) and BH-6',9'-Py2 (ca. 15%) as the minor product, with small quantities of BH-8'-Py 4 (ca. 1%) also being formed. The three new compounds 2, 3a and 4 are characterized by single-crystal X-ray diffraction analyses and by multinuclear multiple-resonance NMR spectroscopy. Compound 2 is of ten-vertex nido:ten-vertex arachno two-atoms-in-common architecture, long postulated for a species with borons-only cluster constitution, but previously elusive. Compound 3a is of unprecedented ten-vertex nido:eight-vertex arachno two-atoms-in-common architecture. The single-crystal X-ray diffraction analysis for the picoline derivative BH(NCHMe)3b, similarly obtained, is also presented. BHPy 4 is also previously unreported but is of known ten-vertex nido:ten-vertex nido two-atoms-in-common architecture of anti configuration, but now with the pyridine ligand positioned differently to other reported examples of BHL compounds. Factors behind the remarkably low solubility of 3a and 3b are elucidated in terms of electrostatic potential (ESP) calculations, polarity, and van der Waals complementarities. In view of contemporary developing high interest in the fluorescent properties of macropolyhedral boron-containing species, a detailed assessment of the photophysical characteristics of 3a and 4 is also presented. In contrast to the thermochromic fluorescence of 2 (from 620 nm brick-red at room temperature to 585 nm yellow at 8 K, quantum yield 0.15), compound 3a is only weakly phosphorescent in the yellow region (590 nm, quantum yield 0.01), whereas compound 4 exhibits no luminescence. The far more photoactive nature of compound 2 is associated with S excited-state minima structures that differ from each other only by the relative rotational positions of the pyridine substituents on its disubstituted ten-vertex {arachno-BPy}-subcluster. The wavelength and relative intensity of fluorescence from these structures depends on the rotational positions of the pyridine ligands, which in turn are influenced by temperature and/or rotational inhibition in the solid-state.

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Section: XXmentioning

confidence: 99%

Substitution of the laser borane anti-B₁₈H₂₂ with pyridine: a structural and photophysical study of some unusually structured macropolyhedral boron hydrides

et al. 2018

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“…In the case of an osmahexaborane, [(PPh 3 ) 2 (CO)OsB 5 H 9 ], reaction with PPh 3 generates [{(PPh 3 ) 2 (CO)OsB 4 H 7 }(BH 2 PPh 3 )] in which a pendant BH 2 PPh 3 group is bound to a basal boron atom. On heating, the original starting osmahexaborane is formed, or it decomposes to give [(PPh 3 ) 2 (CO)OsB 4 H 8 ] and BH 3 PPh 3 28. These differing behaviors reflect the influence of the metal fragments.…”

Section: Methodsmentioning

confidence: 99%

An Iridaborane Reaction Cycle Driven by PMe3 and BH3⋅THF: Synthesis and Characterization of [CpIrB3H7(PMe3)] and [CpIrB2H6(PMe3)]

Macı́as

Fehlner

Beatty

2002

Angew. Chem. Int. Ed.

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“…The motivation for this project was based on our previous success in the interaction of small metallaboranes with bidentate bases wherein pendent phosphine ligands, which exhibit the potential to form linked clusters, were observed. 1 Two substrates came to mind for such a study: [8,8- (PPh 3 ) 2 -nido-8,7-RhSB 9 H 10 ] Unlike the rhodacarborane 2, which is less stable and may rearrange to a more closed configuration 4 (Scheme 2), the rhodathiaborane 1 is stable, easily prepared and has been more extensively studied. 2,3,9 -13 There are novel features associated with compound 1.…”

Section: Introductionmentioning

confidence: 99%

Organometallic chemistry on rhodaheteroborane clusters: reactions with bidentate phosphines and organotransition metal reagents

Volkov

Macı́as

Rath

et al. 2003

Applied Organom Chemis

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This article reviews our recent work on the reactions of the rhodaheteroboranes [8,8-(PPh 3 ) 2 -nido-8,7-RhSB 9 H 10 ] (1) and [9,9-(PPh 3 ) 2 -nido-9,7,8-RhC 2 B 8 H 11 ] (2), and their derivatives, with the bidentate phosphines, dppe [(CH 2 ) 2 (PPh 2 ) 2 ], dppp [(CH 2 ) 3 (PPh 2 ) 2 ], and dppm [CH 2 (PPh 2 ) 2 ], and also with organotransition metal reagents. Simple substitution of the two PPh 3 ligands by a single bidentate phosphine takes place when a 1 : 1 molar ratio of base (dppe or dppp) to rhodathiaborane (1) is used. However, in the presence of an excess of dppe or dppp, products containing 1 or 2 mol of base are formed. These products include a bidentate ligand on the metal and a monodentate ligand on the cage. The displaced hydrogen atom from the cage has moved to the metal center. These bis(ligand) species are unstable with respect to the loss of dihydrogen, affording closo-11 vertex clusters with a pendent phosphine ligand on the cage. In concentrated solutions, the pendent phosphine attacks another cage to afford linked clusters. Under both sets of conditions, when dppm is used, only one product is observed. This species has two dppm ligands coordinated to the metal: one in a unidentate mode and the other bidentate. A similar product is obtained in the reaction of 2 with dppm, although the arrangement of the ligands on the metal in the product is different. Ligand exchange experiments on the dppm-thiaborane system lead to results that provide keys to the reaction pathways in some of these processes. The bis(dppm) derivatives of 1 and 2 are amenable to further derivatization. A second metal may be added, either as an exo-polyhedral atom in a nido cluster in which the metal is part of a bidentate ligand, in the case of 1 and 2, or in a closo cluster derivative of 1 in which the metal is bonded to a dangling PPh 2 moiety. Thus, it was possible to add the metals iridium, rhodium or ruthenium to the cluster, in the case of 1 and ruthenium in the case of 2. However, the reaction of more electrophilic organotransition metal reagents, such as Wilkinson's catalyst, with the dppm derivative of 1 affords species resulting from removal of ligand rather than incorporation of metal, and the products shed light on the rearrangement processes in these systems.

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A Unique Nido Exo-Arachno Equilibrium Involving [(PPh₃)₂(CO)OsB₅H₉] and Its Base Adducts: Crystal and Molecular Structure of [{(PPh₃)₂(CO)OsB₄H₇}(BH₂·PPh₂Me)]

Cited by 23 publications

References 19 publications

Substitution of the laser borane anti-B₁₈H₂₂ with pyridine: a structural and photophysical study of some unusually structured macropolyhedral boron hydrides

Substitution of the laser borane anti-B₁₈H₂₂ with pyridine: a structural and photophysical study of some unusually structured macropolyhedral boron hydrides

An Iridaborane Reaction Cycle Driven by PMe3 and BH3⋅THF: Synthesis and Characterization of [CpIrB3H7(PMe3)] and [CpIrB2H6(PMe3)]

Organometallic chemistry on rhodaheteroborane clusters: reactions with bidentate phosphines and organotransition metal reagents

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A Unique Nido Exo-Arachno Equilibrium Involving [(PPh3)2(CO)OsB5H9] and Its Base Adducts: Crystal and Molecular Structure of [{(PPh3)2(CO)OsB4H7}(BH2·PPh2Me)]

Cited by 23 publications

References 19 publications

Substitution of the laser borane anti-B18H22 with pyridine: a structural and photophysical study of some unusually structured macropolyhedral boron hydrides

Substitution of the laser borane anti-B18H22 with pyridine: a structural and photophysical study of some unusually structured macropolyhedral boron hydrides

An Iridaborane Reaction Cycle Driven by PMe3 and BH3⋅THF: Synthesis and Characterization of [Cp*IrB3H7(PMe3)] and [Cp*IrB2H6(PMe3)]

Organometallic chemistry on rhodaheteroborane clusters: reactions with bidentate phosphines and organotransition metal reagents

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A Unique Nido Exo-Arachno Equilibrium Involving [(PPh₃)₂(CO)OsB₅H₉] and Its Base Adducts: Crystal and Molecular Structure of [{(PPh₃)₂(CO)OsB₄H₇}(BH₂·PPh₂Me)]

Substitution of the laser borane anti-B₁₈H₂₂ with pyridine: a structural and photophysical study of some unusually structured macropolyhedral boron hydrides

Substitution of the laser borane anti-B₁₈H₂₂ with pyridine: a structural and photophysical study of some unusually structured macropolyhedral boron hydrides

An Iridaborane Reaction Cycle Driven by PMe3 and BH3⋅THF: Synthesis and Characterization of [CpIrB3H7(PMe3)] and [CpIrB2H6(PMe3)]