Hélène Cattey

s -Aryltetrazines are assembled into macrocyclic tri- and tetramers by direct C–C bond formation via Ullmann homocoupling of bromophenyltetrazines. Short aryltetrazine linkages afford compact redox-active macrocycles with small internal cavities.

The correlation between delocalization (DI) and penetration ( p ) indexes partitions bonding interactions into bond types. This methodology was applied to the bonding analysis of Ti/Ir heterobimetallic complexes derived from ambiphilic phosphides.

The new monohydrated n-hexylammonium hydrogen oxalate salt [HexNH3]2[HC2O4]2·H2O (1) (HexNH3 = C6H16N+) has been prepared at room temperature, by mixing dehydrated oxalic acid with n-hexylamine. Salt 1 isolated as single-crystals, crystallizes in the orthorhombic system (space group Pna21) with cell constants of a = 14.1534(8) Å, b = 5.6656(3) Å, c = 26.8153(16) Å, V = 2150.3(2) Å3 and Z = 4. Two n-hexylammonium cations, two hydrogen oxalate anions, and one water molecule compose the asymmetric unit. All components of salt 1 are linked through N-H···O and O-H···O hydrogen bonding interactions leading to an extended supramolecular self-assembly. Structural characterization of 1 was completed by infrared and UV-visible spectroscopy. Elemental analysis (C, H, and N) also corroborates the X-ray crystal structure. The antibacterial activity of salt 1 against a bacterial species of the genus Streptomyces, extracted from potatoes, was then investigated. The antibiotic susceptibility test revealed that the bacteria were highly sensitive to salt, from a concentration of 6 mg/mL, thus acting as an effective bactericide.

Four novel crystalline architectures based on benzo[c]cinnolininium trifluoromethanesulonate salts, [C₁₂H₉N₂]⁺[CF₃SO₃]⁻, have been isolated as single-crystals, and their structures have been determined by X-ray diffraction analysis. The formation of the new salts results from reactions involving the dimeric hydroxo di-n-butylstannane trifluoromethanesulfonato complex [n-Bu₂Sn(OH)(H₂O)(CF₃SO₃)]₂ (1) and benzo[c]cinnoline (C₁₂H₈N₂, BCC). Organic salts I, II, III, and IV were crystallized through slow evaporation at room temperature from a mixture of toluene/dichloromethane. The cystallographic structures of I, II, and IV exhibit the presence of monoprotonated benzo[c]cinnolinium cations in interactions with a free benzo[c]cinnoline molecule through N–H···N hydrogen bonding, while for salt III, the monoprotonated cation directly interacts with the CF₃SO₃⁻ anion via an N–H···O interaction. For all four salts, aromatic π-π interactions involving rings of various components (free benzo[c]cinnoline molecule, benzo[c]cinnolinium cation, toluene molecule), combined with weak C–H···O and C–H···F interactions implying the trifluoromethanesulfonate anion, promote the solid-state self-assembly of supramolecular stacks. In parallel to the formation of benzo[c]cinnolinium based-salts, organotin(IV) 1 was converted into a distannoxane compound, ²_∞{[n-Bu₂(μ-OH)SnOSn(μ-η²-O₃SCF₃)n-Bu₂]₂[n-Bu₂(η¹-O₃SCF₃)SnOSn(μ-OH)n-Bu₂]₂} (3), which was also isolated as a single crystal and whose crystallographic structure was previously established by us.

The N‐directed rhodium‐catalyzed CH bond arylation of s‐aryltetrazine is reported using arylboronic acids as coupling partners. Convenient synthetic conditions are identified that avoid the 1,4‐azaphilic addition of the organometallic reagents on the tetrazine core, that may occur with organometallic nucleophiles, such as aryl cuprates. Thus, using [RhCl₂Cp*]₂ and Cu(OAc)₂ in trifluoromethylbenzene favors the CH activation and direct arylation of the s‐tetrazine. This setup tolerates both electron‐donating and electron‐withdrawing groups on the (hetero)aryl boronic acids. Electron‐rich aryl coupling partners display a higher reactivity, and allow the formation of polyaromatic derivatives. This methodology provides a facile and straightforward route to diversely structured polyaromatics incorporating the valuable s‐tetrazine core, with so‐called T‐shaped and Z‐shaped architectures.

We report herein novel polyarylated diphenylphosphino‐1‐fluoranthenyl ligands by rhodium‐catalyzed phosphine‐directed C−H arylation. The nature of the rhodium precatalysts that is employed plays an essential role for the control of the reaction and its resulting product. By using the dimeric [Rh^(III)Cl₂Cp*]₂ as the catalyst, a “classical” single peri‐functionalization of the polycyclic aromatic hydrocarbons phosphine selectively occurs. Conversely, the use of the ionic [Rh^(I)(COD)₂] BF₄ as the catalyst reveals an unexpected post‐rearrangement that is characterized by the migration of the directing phosphino‐group on the inserted aryl moiety. In this process, a concurrent cascade extension of the functionalization is also achieved by the introduction of a second aryl moiety. We focused our attention on the rhodium catalytic species formed, and the five or seven‐membered rhodacycles as intermediates involved in these C−H catalytic cascade processes. Besides the electronic effects attached to Rh(I) and Rh(III) precatalysts, either cationic or neutral, our results clearly suggest the role of the pentamethylcyclopentadienyl substituent in the selectivity of peri‐C−H‐arylation. Conversely, rhodium stabilized by weakly bonded more fluxional bis‐cyclooctadienyl ligands enters more easily into further reactivity, promoting 2‐fold arylation reactions or even participate to diphenylphosphino group rearrangement.

The reactivity of the hydroxo di- n -butyltin trifluoromethanesulfonato dimer complex [ n -Bu ₂ Sn(µ-OH)(H ₂ O)(CF ₃ SO ₃ )] ₂ ( 1 ) toward 1,10-phenanthroline (phen) has been investigated, leading to the formation of two novel di- n -butyltin(IV) trifluoromethanesulfonate complexes [ n -Bu ₂ Sn(µ-OH)(phen)] ₂ [CF ₃ SO ₃ ] ₂ ( 5 ) and [ n -Bu ₂ Sn(phen) ₂ ][CF ₃ SO ₃ ] ₂ ( 6 ), in which the tin atoms are bis-chelated by one and two bidentate phen ligands, respectively. Salts 5 and 6 were characterized by single crystal X-ray diffraction analysis, elemental analysis, mass spectrometry, and infrared spectroscopy as well as ¹ H, ¹⁹ F, ¹³ C{ ¹ H}, and ¹¹⁹ Sn{ ¹ H} NMR spectroscopy. Monitoring by ¹¹⁹ Sn{ ¹ H} NMR spectroscopy in CD ₃ CN solution of the reaction proceeding with successive addition of phen revealed the in situ formation of three organotin(IV) trifluoromethanesulfonate intermediate species. Two of these, namely {[ n -Bu ₂ Sn(H ₂ O)] ₂ O· n -Bu ₂ Sn(OH) ₂ }[CF ₃ SO ₃ ] ₂ ( 2 ) and [ n -Bu ₂ Sn ₂ (OH)(CF ₃ SO ₃ )] ₂ O ( 4 ), were already known and could be clearly identified on the basis of their ¹¹⁹ Sn{ ¹¹⁹ H} NMR chemical shifts. The composition of the third intermediate, 3 , with an unknown chemical shift value, was investigated. A possible structure, especially suggested by electrospray-ionization mass spectrometry, is proposed as [{ n -Bu ₂ Sn(phen)(CF ₃ SO ₃ )} ₂ (µ-CF ₃ SO ₃ )][CF ₃ SO ₃ ]. Furthermore, from a mixture of 1 and phen in equimolar ratio, in dichloromethane solvent and at –20 °C, temperature-sensitive crystals of a new hydrated di- n -butyltin cation, [ n -Bu ₂ Sn(phen)(OH)(H ₂ O)][CF ₃ SO ₃ ] ( 7 ), were isolated. Crystals of the organic salt 1,10-phenanthrolinium trifluoromethanesulfonate (phenHOTf) were also obtained from the filtrate of the mother-liquor. The reactivity of 1 toward 2,9-dimethyl-1,10-phenanthroline was also explored (dmphen), leading to the detection of characteristic fingerprints of distannoxanes 2 and 4 by ¹¹⁹ Sn{ ¹¹⁹ H} NMR, and to the crystallization of phenanthrolinium triflate salts, which were characterized by X-ray diffraction analysis as dmphenHOTf and dmphenHOTf·dmphen .

Despite recent tremendous progress in the synthesis of nonplanar chiral aromatics, and helicenes in particular, their conversion to half‐sandwich or sandwich transition metal complexes still lags behind, although they represent an attractive family of modular and underexplored chiral architectures with a potential catalytic use. In this work, starting from various chiral helicene‐indene proligands, we prepared the enantio‐ and diastereopure oxa[6]‐ and oxa[7]helicene‐indenido half‐sandwich Rh^I and Rh^III complexes and oxa[7]helicene‐bisindenido ansa‐metallocene Fe^II complex. To document their use, oxahelicene‐indenido half‐sandwich Rh^III complexes were employed as chiral catalysts in enantioselective C−H arylation of benzo[h]quinolines with 1‐diazonaphthoquinones to afford a series of axially chiral biaryls in mostly good to high yields and in up to 96 : 4 er. Thus, we developed stereocontrolled synthesis of chiral helicene‐indenido ansa‐ and half‐sandwich metal complexes, successfully demonstrated the first use of such helicene Cp‐related metal complexes in enantioselective catalysis, and described an unusual sequence of efficient central‐to‐helical‐to‐planar‐to‐axial chirality transfer.