Jean-francois Halet - Academia.edu (original) (raw)
Papers by Jean-francois Halet
![Research paper thumbnail of Synthesis, Structure and Bonding of the Tungstaboranes [Cp*W(CO)2B3H8] and [(Cp*W)3(CO)2B4H7]](https://attachments.academia-assets.com/103962698/thumbnails/1.jpg)
](Inorganics
The structure and bonding of two novel tungstaboranes which were synthesized using diverse synthe... more The structure and bonding of two novel tungstaboranes which were synthesized using diverse synthetic methods are described. (i) The room-temperature photolysis of [Cp*W(CO)3Me] with [BH3·SMe2] led to the isolation of the hydrogen-rich tungstaborane [Cp*W(CO)2B3H8] (1). Its geometry consists of an arachno butterfly core similar to tetraborane(10) and obeys the Wade-Mingos electron counting rules (n vertices, n + 3 skeletal electron pairs (seps)). (ii) Further, the tungstaborane [(Cp*W)3(μ-H)2(μ3-H)(μ-CO)2B4H4] (4) was isolated by thermolysis reaction of a tungsten intermediate, obtained by low temperature reaction of [Cp*WCl4] and [LiBH4·THF] with [Cr(CO)5·THF]. Compound 4 which seems to have formed by replacement of a BH unit in [(Cp*W)2B5H9] by the isoelectronic fragment {Cp*W(CO)2}, adopts an oblato-nido hexagonal-bipyramidal core (n vertices, n–1 seps). Both compounds were characterized using multinuclear NMR, IR spectroscopy, mass spectrometry as well as single crystal X-ray dif...
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Dalton Transactions, 2021
New synthetic methods for the Ta-aziridine species [Cp*TaBH(C7H4NS2)CH2S2NC6H4] and the 16-electr... more New synthetic methods for the Ta-aziridine species [Cp*TaBH(C7H4NS2)CH2S2NC6H4] and the 16-electron half-sandwich complex [Cp*TaCl3{κ2-N,S-C6H4SNCS}] having κ2-N,S coordination mode have been developed.
Zeitschrift für Naturforschung B, 2021
The ternary rare earth metal boride silicide Er3Si5–x B (x = 1.17) was synthesized from the eleme... more The ternary rare earth metal boride silicide Er3Si5–x B (x = 1.17) was synthesized from the elements using the tin flux method. It crystallizes in a new structure type in the space group R32 (a = 6.5568(1) Å, c = 24.5541(1) Å, Z = 6). The structural arrangement can be derived from the AlB2 structure type with boron/silicon ordering in the layered metalloid substructure made of [Si5B] hexagons. The presence or absence of the boron atoms involved in this ordered structure is discussed on the basis of difference Fourier syntheses and structural analysis, in relation with the binary parent structures AlB2 and Yb3Si5 (Th3Pd5 type). The electronic and bonding properties of Er3Si5–x B were analyzed and discussed via density functional theory (DFT) calculations and a crystal orbital Hamiltonian population (COHP) bonding analysis.
New Journal of Chemistry, 2020
Various bimetallic bis- and tris-homocubane analogues of group 9 transition metals have been isol... more Various bimetallic bis- and tris-homocubane analogues of group 9 transition metals have been isolated and structurally characterized employing Li[BH2E3] (E = S or Se).
Chemistry - A European Journal, 2017
Dedicated to our very good friend Thomas P. Fehlner on the occasion of his 80th Birthday.
Chemistry (Weinheim an der Bergstrasse, Germany), Jan 25, 2017
A series of new bis()borate and agostic complexes of group 7 metals have been synthesized and st... more A series of new bis()borate and agostic complexes of group 7 metals have been synthesized and structurally characterized from various borate ligands, such as, Na[(H3B)bbza], Na[(H3B)abz] and Na[(H2B)mp2] (bbza = bis(benzothiazol-2-yl)amine, abz = 2-aminobenzothiazolyl and mp = 2-mercaptopyridyl). Photolysis of [Mn2(CO)10] with Na[(H3B)bbza] led to the formation of bis()borate complex [Mn(CO)3(μ-H)2BHNCSC6H4(NR)], 1 (R = NCSC6H4). Under similar reaction conditions, [Re2(CO)10] generated an octahedral complex [Re(CO)2(N3C2S2C12H8)2], 2. In a similar method, when [Mn2(CO)10] was treated with Na[(H3B)abz], reaction led to the formation of a bis()borate complex [Mn(CO)3(μ-H)2BH(RN2CS-C6H4)], 3 and an agostic complex [Mn(CO)3(μ-H)BH(RN2CSC6H4)2], 4 (R = H). In an attempt to probe the possibility for the formation of agostic complexes of the heavier group 7 metals, we carried out the photolysis of [M2(CO)10] with Na[(H2B)mp2] that led to the formation of [M(CO)3(μ-H)BH(C5H4NS)2], 5 and ...
ChemInform, 2016
The reaction of protected β-hydroxy acylsilanes (I) and (XII) with sulfones provides (E)-silyl en... more The reaction of protected β-hydroxy acylsilanes (I) and (XII) with sulfones provides (E)-silyl enol ethers, whereas the reaction with Grignard reagent (V) give the (Z)-isomers (VI) as sole products.
The Chemical Bond I, 2016
Although there will always be an Edisonian component to a search for new cluster compounds, the g... more Although there will always be an Edisonian component to a search for new cluster compounds, the greater the understanding of the underlying chemistry, the more focused and efficient the search. It is why the rapid expansion of the synthesis and characterization of ligated transition-metal clusters over the last decades has been accompanied by theories about their bonding and electronic properties with the aid of conceptual ideas and theoretical models such as the development of electron-counting rules which govern the relationship between the structure and the electron count. This review summarizes these theoretical models, their historical development, their limits, and using a selection of specific examples among the extensive panoply of large ligated metal clusters available in the literature, shows how they can help in understanding their structural and electronic properties.
Journal of Cluster Science, 2014
Based on density functional calculations on model systems, the electronic structure of medium and... more Based on density functional calculations on model systems, the electronic structure of medium and large ligated palladium clusters is discussed herein. Among all the studied clusters, the electronic structure of Pd 30 ðCOÞ 26 ðPR 3 Þ 10 , Pd 69 ðCOÞ 36 ðPR 3 Þ 18 and Pd 145 ðCOÞ 56 ðPR 3 Þ 30 clusters is analyzed in details. It is shown that the evolution of the band gap can be correlated to the average Pd-Pd bond length rather than n, the nuclearity of the cluster.
Journal of molecular modeling, 2015
DFT calculations were carried out on the homo- and hetero-bimetallic model wires [(η(5)-C5H5)(dpe... more DFT calculations were carried out on the homo- and hetero-bimetallic model wires [(η(5)-C5H5)(dpe)Fe-C≡C-C6H4-C≡C-Fe(dpe)(η(5)-C5H5)] (1'), [(η(7)-C7H7)(dpe)Mo-C≡C-C6H4-C≡C-Mo(dpe)(η(7)-C7H7)] (2'), and [(η(5)-C5H5)(dpe)Fe-C≡C-C6H4-C≡C-Mo(dpe)(η(7)-C7H7)] (3') used to tentatively mimic [(η(5)-C5Me5)(dppe)Fe-C≡C-C6H4-C≡C-Fe(dppe)(η(5)-C5Me5)] (1), [(η(7)-C7H7)(dppe)Mo-C≡C-C6H4-C≡C-Mo(dppe)(η(7)-C7H7)] (2), and [(η(5)-C5Me5)(dppe)Fe-C≡C-C6H4-C≡C-Mo(dppe)(η(7)-C7H7)] (3), respectively in order to analyze the similarities and the differences between models and real compounds previously theoretically and experimentally studied, with respect to their molecular structures and properties. A comparison of the metrical data computed for the models and the real systems shows some slight discrepancy between the metal-ancillary ligand distances - shorter distances are observed in the formers - but comparable metal-Cα and Cα-Cβ distances. Incidentally, distances computed for the model...
Journal of the Chemical Society, Dalton Transactions, 2001
ABSTRACT
Clusters can be viewed as solids at the nano-scale, yet molecular cluster chemistry and solid sta... more Clusters can be viewed as solids at the nano-scale, yet molecular cluster chemistry and solid state chemistry have traditionally been considered as separate topics. This treatment has made it conceptually difficult to appreciate commonalities of structure and bonding between the two. Using analogous models, this is the first book to form a connecting bridge. Although the focus is on clusters, sufficient attention is paid to solid-state compounds at each stage of the development to establish the interrelationship between the two topics. Comprehensive coverage of cluster types by composition, size and ligation, is provided, as is a synopsis of selected research. Written in an accessible style and highly illustrated to aid understanding, this book is suitable for researchers in inorganic chemistry, physical chemistry, materials science, and condensed matter physics.
Theoretical Chemistry Accounts, 2013
Density functional theory (DFT) calculations were used to probe the reaction of the diruthenabora... more Density functional theory (DFT) calculations were used to probe the reaction of the diruthenaborane nido-[1,2-(Cp*RuH) 2 B 3 H 7 ] (Cp* = g 5-C 5 Me 5), (1) with MeC : CMe to form the major product nido-[1,2-(Cp*Ru) 2 (l-H)(l-BH 2)-4,5-Me 2-4,5-C 2 B 2 H 4 ] (2) along with minor product nido-(Cp*Ru) 2-4,5-Me 2-4,5-C 2 B 2 H 6 (3). The structural features of the other related diruthenacarboranes, nido-(Cp*Ru) 2-4,5-Me 2-4,5-C 2 B 2 H 6 (4) and closo-1,2-(Cp* RuH) 2-4,5-Me 2-4,5-C 2 B 3 H 3 (5), were also studied. Since metallaheteroboranes with p-block group-14 elements are rare, we extend our DFT studies to explore the reaction of 1 with heavier group-14 alkyne analogs, RE : ER (E = Si, Ge, and Sn; R = alkyl or aryl groups). The geometrical and electronic structures of the products nido-[1,2-(Cp*Ru) 2 (l-H) (l-BH 2)-4,5-Me 2-4,5-E 2 B 2 H 4 ] (E = Si (6), Ge (7), Sn (8)) are described and compared with the ruthenacarborane analog, nido-[1,2-(Cp*Ru) 2 (l-H)(l-BH 2)-4,5-Me 2-4,5-C 2 B 2 H 4 ] species, 2. The computed energetics and the geometries support the feasibility of the reaction and the stability of the products. NBO analysis was performed to delve further into the nature of the bonding in this kind of clusters.
Journal of the American Chemical Society, 1988
Molecular orbital calculations on carbido-transition-metal carbonyl cluster compounds where the c... more Molecular orbital calculations on carbido-transition-metal carbonyl cluster compounds where the carbon atom lies in a large cavity indicate a substantial buildup of negative charge on the carbon atom. Besides making the carbon more susceptible to protonic attack the large cavity assists the stabilization of interstitial C-H fragments.
Journal of Cluster Science, 2007
Extended Hückel Theory (EHT) and Density Functional Theory (DFT) calculations on hexacapped cubic... more Extended Hückel Theory (EHT) and Density Functional Theory (DFT) calculations on hexacapped cubic aluminum clusters of the type [(AlH)8(μ4-CH)6−n (μ4-H) n ]+/−q (n ≤ 6) indicate that their favored number of skeletal electron pairs (SEP), 12 SEPs for n ≥ 3, 14 SEPs for n = 2, 16 SEPs for n = 1 and 18 SEPs for n = 0, depends on the relative number of the two types of
Journal of Cluster Science, 2013
ABSTRACT
Inorganics
The structure and bonding of two novel tungstaboranes which were synthesized using diverse synthe... more The structure and bonding of two novel tungstaboranes which were synthesized using diverse synthetic methods are described. (i) The room-temperature photolysis of [Cp*W(CO)3Me] with [BH3·SMe2] led to the isolation of the hydrogen-rich tungstaborane [Cp*W(CO)2B3H8] (1). Its geometry consists of an arachno butterfly core similar to tetraborane(10) and obeys the Wade-Mingos electron counting rules (n vertices, n + 3 skeletal electron pairs (seps)). (ii) Further, the tungstaborane [(Cp*W)3(μ-H)2(μ3-H)(μ-CO)2B4H4] (4) was isolated by thermolysis reaction of a tungsten intermediate, obtained by low temperature reaction of [Cp*WCl4] and [LiBH4·THF] with [Cr(CO)5·THF]. Compound 4 which seems to have formed by replacement of a BH unit in [(Cp*W)2B5H9] by the isoelectronic fragment {Cp*W(CO)2}, adopts an oblato-nido hexagonal-bipyramidal core (n vertices, n–1 seps). Both compounds were characterized using multinuclear NMR, IR spectroscopy, mass spectrometry as well as single crystal X-ray dif...
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Dalton Transactions, 2021
New synthetic methods for the Ta-aziridine species [Cp*TaBH(C7H4NS2)CH2S2NC6H4] and the 16-electr... more New synthetic methods for the Ta-aziridine species [Cp*TaBH(C7H4NS2)CH2S2NC6H4] and the 16-electron half-sandwich complex [Cp*TaCl3{κ2-N,S-C6H4SNCS}] having κ2-N,S coordination mode have been developed.
Zeitschrift für Naturforschung B, 2021
The ternary rare earth metal boride silicide Er3Si5–x B (x = 1.17) was synthesized from the eleme... more The ternary rare earth metal boride silicide Er3Si5–x B (x = 1.17) was synthesized from the elements using the tin flux method. It crystallizes in a new structure type in the space group R32 (a = 6.5568(1) Å, c = 24.5541(1) Å, Z = 6). The structural arrangement can be derived from the AlB2 structure type with boron/silicon ordering in the layered metalloid substructure made of [Si5B] hexagons. The presence or absence of the boron atoms involved in this ordered structure is discussed on the basis of difference Fourier syntheses and structural analysis, in relation with the binary parent structures AlB2 and Yb3Si5 (Th3Pd5 type). The electronic and bonding properties of Er3Si5–x B were analyzed and discussed via density functional theory (DFT) calculations and a crystal orbital Hamiltonian population (COHP) bonding analysis.
New Journal of Chemistry, 2020
Various bimetallic bis- and tris-homocubane analogues of group 9 transition metals have been isol... more Various bimetallic bis- and tris-homocubane analogues of group 9 transition metals have been isolated and structurally characterized employing Li[BH2E3] (E = S or Se).
Chemistry - A European Journal, 2017
Dedicated to our very good friend Thomas P. Fehlner on the occasion of his 80th Birthday.
Chemistry (Weinheim an der Bergstrasse, Germany), Jan 25, 2017
A series of new bis()borate and agostic complexes of group 7 metals have been synthesized and st... more A series of new bis()borate and agostic complexes of group 7 metals have been synthesized and structurally characterized from various borate ligands, such as, Na[(H3B)bbza], Na[(H3B)abz] and Na[(H2B)mp2] (bbza = bis(benzothiazol-2-yl)amine, abz = 2-aminobenzothiazolyl and mp = 2-mercaptopyridyl). Photolysis of [Mn2(CO)10] with Na[(H3B)bbza] led to the formation of bis()borate complex [Mn(CO)3(μ-H)2BHNCSC6H4(NR)], 1 (R = NCSC6H4). Under similar reaction conditions, [Re2(CO)10] generated an octahedral complex [Re(CO)2(N3C2S2C12H8)2], 2. In a similar method, when [Mn2(CO)10] was treated with Na[(H3B)abz], reaction led to the formation of a bis()borate complex [Mn(CO)3(μ-H)2BH(RN2CS-C6H4)], 3 and an agostic complex [Mn(CO)3(μ-H)BH(RN2CSC6H4)2], 4 (R = H). In an attempt to probe the possibility for the formation of agostic complexes of the heavier group 7 metals, we carried out the photolysis of [M2(CO)10] with Na[(H2B)mp2] that led to the formation of [M(CO)3(μ-H)BH(C5H4NS)2], 5 and ...
ChemInform, 2016
The reaction of protected β-hydroxy acylsilanes (I) and (XII) with sulfones provides (E)-silyl en... more The reaction of protected β-hydroxy acylsilanes (I) and (XII) with sulfones provides (E)-silyl enol ethers, whereas the reaction with Grignard reagent (V) give the (Z)-isomers (VI) as sole products.
The Chemical Bond I, 2016
Although there will always be an Edisonian component to a search for new cluster compounds, the g... more Although there will always be an Edisonian component to a search for new cluster compounds, the greater the understanding of the underlying chemistry, the more focused and efficient the search. It is why the rapid expansion of the synthesis and characterization of ligated transition-metal clusters over the last decades has been accompanied by theories about their bonding and electronic properties with the aid of conceptual ideas and theoretical models such as the development of electron-counting rules which govern the relationship between the structure and the electron count. This review summarizes these theoretical models, their historical development, their limits, and using a selection of specific examples among the extensive panoply of large ligated metal clusters available in the literature, shows how they can help in understanding their structural and electronic properties.
Journal of Cluster Science, 2014
Based on density functional calculations on model systems, the electronic structure of medium and... more Based on density functional calculations on model systems, the electronic structure of medium and large ligated palladium clusters is discussed herein. Among all the studied clusters, the electronic structure of Pd 30 ðCOÞ 26 ðPR 3 Þ 10 , Pd 69 ðCOÞ 36 ðPR 3 Þ 18 and Pd 145 ðCOÞ 56 ðPR 3 Þ 30 clusters is analyzed in details. It is shown that the evolution of the band gap can be correlated to the average Pd-Pd bond length rather than n, the nuclearity of the cluster.
Journal of molecular modeling, 2015
DFT calculations were carried out on the homo- and hetero-bimetallic model wires [(η(5)-C5H5)(dpe... more DFT calculations were carried out on the homo- and hetero-bimetallic model wires [(η(5)-C5H5)(dpe)Fe-C≡C-C6H4-C≡C-Fe(dpe)(η(5)-C5H5)] (1'), [(η(7)-C7H7)(dpe)Mo-C≡C-C6H4-C≡C-Mo(dpe)(η(7)-C7H7)] (2'), and [(η(5)-C5H5)(dpe)Fe-C≡C-C6H4-C≡C-Mo(dpe)(η(7)-C7H7)] (3') used to tentatively mimic [(η(5)-C5Me5)(dppe)Fe-C≡C-C6H4-C≡C-Fe(dppe)(η(5)-C5Me5)] (1), [(η(7)-C7H7)(dppe)Mo-C≡C-C6H4-C≡C-Mo(dppe)(η(7)-C7H7)] (2), and [(η(5)-C5Me5)(dppe)Fe-C≡C-C6H4-C≡C-Mo(dppe)(η(7)-C7H7)] (3), respectively in order to analyze the similarities and the differences between models and real compounds previously theoretically and experimentally studied, with respect to their molecular structures and properties. A comparison of the metrical data computed for the models and the real systems shows some slight discrepancy between the metal-ancillary ligand distances - shorter distances are observed in the formers - but comparable metal-Cα and Cα-Cβ distances. Incidentally, distances computed for the model...
Journal of the Chemical Society, Dalton Transactions, 2001
ABSTRACT
Clusters can be viewed as solids at the nano-scale, yet molecular cluster chemistry and solid sta... more Clusters can be viewed as solids at the nano-scale, yet molecular cluster chemistry and solid state chemistry have traditionally been considered as separate topics. This treatment has made it conceptually difficult to appreciate commonalities of structure and bonding between the two. Using analogous models, this is the first book to form a connecting bridge. Although the focus is on clusters, sufficient attention is paid to solid-state compounds at each stage of the development to establish the interrelationship between the two topics. Comprehensive coverage of cluster types by composition, size and ligation, is provided, as is a synopsis of selected research. Written in an accessible style and highly illustrated to aid understanding, this book is suitable for researchers in inorganic chemistry, physical chemistry, materials science, and condensed matter physics.
Theoretical Chemistry Accounts, 2013
Density functional theory (DFT) calculations were used to probe the reaction of the diruthenabora... more Density functional theory (DFT) calculations were used to probe the reaction of the diruthenaborane nido-[1,2-(Cp*RuH) 2 B 3 H 7 ] (Cp* = g 5-C 5 Me 5), (1) with MeC : CMe to form the major product nido-[1,2-(Cp*Ru) 2 (l-H)(l-BH 2)-4,5-Me 2-4,5-C 2 B 2 H 4 ] (2) along with minor product nido-(Cp*Ru) 2-4,5-Me 2-4,5-C 2 B 2 H 6 (3). The structural features of the other related diruthenacarboranes, nido-(Cp*Ru) 2-4,5-Me 2-4,5-C 2 B 2 H 6 (4) and closo-1,2-(Cp* RuH) 2-4,5-Me 2-4,5-C 2 B 3 H 3 (5), were also studied. Since metallaheteroboranes with p-block group-14 elements are rare, we extend our DFT studies to explore the reaction of 1 with heavier group-14 alkyne analogs, RE : ER (E = Si, Ge, and Sn; R = alkyl or aryl groups). The geometrical and electronic structures of the products nido-[1,2-(Cp*Ru) 2 (l-H) (l-BH 2)-4,5-Me 2-4,5-E 2 B 2 H 4 ] (E = Si (6), Ge (7), Sn (8)) are described and compared with the ruthenacarborane analog, nido-[1,2-(Cp*Ru) 2 (l-H)(l-BH 2)-4,5-Me 2-4,5-C 2 B 2 H 4 ] species, 2. The computed energetics and the geometries support the feasibility of the reaction and the stability of the products. NBO analysis was performed to delve further into the nature of the bonding in this kind of clusters.
Journal of the American Chemical Society, 1988
Molecular orbital calculations on carbido-transition-metal carbonyl cluster compounds where the c... more Molecular orbital calculations on carbido-transition-metal carbonyl cluster compounds where the carbon atom lies in a large cavity indicate a substantial buildup of negative charge on the carbon atom. Besides making the carbon more susceptible to protonic attack the large cavity assists the stabilization of interstitial C-H fragments.
Journal of Cluster Science, 2007
Extended Hückel Theory (EHT) and Density Functional Theory (DFT) calculations on hexacapped cubic... more Extended Hückel Theory (EHT) and Density Functional Theory (DFT) calculations on hexacapped cubic aluminum clusters of the type [(AlH)8(μ4-CH)6−n (μ4-H) n ]+/−q (n ≤ 6) indicate that their favored number of skeletal electron pairs (SEP), 12 SEPs for n ≥ 3, 14 SEPs for n = 2, 16 SEPs for n = 1 and 18 SEPs for n = 0, depends on the relative number of the two types of
Journal of Cluster Science, 2013
ABSTRACT