66479-06-9Relevant articles and documents
Halogenation of Diorganotelluride [2,6-(Me2NCH2)2C6H3]TenBu: Synthesis, Molecular and Electronic Structural Investigation of Monoorgano Dihalotelluronium(IV) Cation
Butcher, Ray J.,Deka, Rajesh,Gupta, Anand,Sarkar, Arup,Singh, Harkesh B.
, p. 4170 - 4179 (2020)
A simple methodology for the synthesis of heteroleptic diorganotelluride [2,6-(Me2NCH2)2C6H3]TenBu (1) and homoleptic diorganotelluride [2,6-(Me2NCH2)2C6H3]2Te (2) is reported. The halogenation reactions of diorganotelluride 1 are studied. In particular, the reaction of 1 with Br2 resulted in the isolation of a monoorgano dibromotelluronium(IV) cation, namely [2,6-(Me2NCH2)2C6H3TeBr2]·Br3 ([3]·Br3). The reaction of [3]·Br3 with K2PdCl4 afforded a monoorgano mixed dihalotelluronium(IV) cation, [2,6-(Me2NCH2)2C6H3TeClBr]·PdBr4 ([4]·PdBr4). When diorganotelluride 1 was treated with I2, the reaction afforded the tellurenium(II) cation, [2,6-(Me2NCH2)2C6H3Te]·I2·I3 ([5]·I2·I3). The reaction of 1 with HgCl2 resulted in the isolation of dimeric diorganoditelluroxonium(IV) cation, [2,6-(Me2NCH2)2C6H3Te(μ-O)]2·Hg2Cl6 ([6]·Hg2Cl6). A similar diorganoditelluroxonium(IV) cation, namely [2,6-(Me2NCH2)2C6H3Te(μ-O)]2·2Br ([6]·2Br) was also obtained by the reaction of 1 with Br2 and NaOH. The crystallographic studies suggest that for each compound, both the N atoms from the pendant arms make strong Intramolecular Chalcogen Bonding (IChB) interactions with the Te center(s). The presence of a strong N→Te IChB interaction in the synthesized compounds was further validated by DFT calculations.
Synthesis of Air- and moisture-stable dibenzogallepins: Control of planarity of seven-membered rings in solid states by coordination to gallium atoms
Matsumoto, Takuya,Takamine, Hirofumi,Tanaka, Kazuo,Chujo, Yoshiki
, p. 1593 - 1596 (2015)
Air- and moisture-stable dibenzo[b,f]gallepins with planar seven-membered rings have been designed and synthesized. From X-ray single-crystal analyses, the effects of the coordination numbers were evaluated at the gallium atom on the planarity of the seven-membered rings with a series of the synthesized complexes. Accordingly, it was shown that the seven-membered ring of dibenzogallepin involving a three-coordinated gallium atom presented the highest planarity compared to other dibenzogallepins with four- or five-coordinated gallium atoms. In addition, from theoretical calculations, it was proposed that the electronic states of the gallium atom in the complexes contributed to the energy levels of LUMOs+1.
Aerobic oxidation-functionalization of the aryl moiety in van Koten's pincer complex (NCN)Ni(ii)Br: Relevance to carbon-heteroatom coupling reactions promoted by high-valent nickel species
Cloutier, Jean-Philippe,Zamani, Fahimeh,Zargarian, Davit
, p. 1800 - 1807 (2022/01/31)
The growing popularity of metal-promoted C-H functionalization methodologies has led to increased efforts aimed at improving our understanding of the mechanistic underpinnings of C-C and C-heteroatom bond forming steps. One approach to such mechanistic studies involves probing the reactivities of model complexes featuring chelate-stabilized M-hydrocarbyl moieties. The present study uses van Koten's (NCN)Ni(ii)Br compound as a model for probing C-heteroatom coupling with protic substrates HX (X = NHR, OR). Our results establish the crucial importance of aerobic (oxidative) conditions for promoting reactivities that give the functionalized ligands NC(X)N. The importance of oxidation for the C-heteroatom bond formation is further deduced from the reaction of the structurally authenticated complex (NCN)Ni(OSiMe3) with CuBr2 to give the C-O functionalization product NC(OSiMe3)N. This journal is
Functionalization of the Aryl Moiety in the Pincer Complex (NCN)NiIIIBr2: Insights on NiIII-Promoted Carbon-Heteroatom Coupling
Cloutier, Jean-Philippe,Zargarian, Davit
supporting information, p. 1446 - 1455 (2018/05/23)
This report describes the C-O, C-N, and C-halogen functionalization of the NiIII-Ar moiety stabilized within a pincer framework that serves as a model system for studying C-heteroatom coupling reactions promoted by high-valent Ni compounds. Treating van Koten's pincer complex (NCN)NiIIIBr2 under a nitrogen atmosphere with water, 1° or 2° alcohols, 1° amines, HCl, or HBr results in heterofunctionalization at the ipso-C of the pincer ligand's aryl moiety. The yields of these heterofunctionalizations are generally a comproportionation reaction between the trivalent precursor and a NiI species arising from the reductive elimination step in the functionalization process. Other side-reactions include a C-OH coupling with residual water and C-H coupling (net protonation) that is prevalent with mineral acids, some alcohols, and aqueous NH3. Kinetic measurements have established that the reaction with MeOH is first-order with respect to [(NCN)NiIIIBr2], and a kinetic isotope effect of 0.47 has been obtained for functionalization with CH3OH/CD3OD. These and other observations have allowed us to propose two different mechanistic postulates for the involvement of trivalent intermediates in the functionalization reactions under discussion. Tetravalent species such as [(NCN)NiIVBr2]+ can be generated in situ under strongly oxidative conditions and they do promote C-Br coupling, but such species play no role in the C-heteroatom coupling reactions under nonoxidative conditions.
Intramolecularly coordinated arylmagnesium compounds: effects on the Schlenk equilibrium
Markies, Peter R.,Altink, Rinke M.,Villena, Alan,Akkerman, Otto S.,Bickelhaupt, Friedrich,et al.
, p. 289 - 312 (2007/10/02)
A series of phenylmagnesium bromides (1, 3-8) with ortho-substituents capable of forming intramolecular coordinative bonds along with the corresponding diarylmagnesium compounds (1a, 3a-6a, 8a) have been synthesized.The thermodynamic parameters ΔHs and ΔSs for the Schlenk equilibria (2 ArMgBr Ar2Mg + MgBr2) have been determined by variable temperature NMR spectroscopy.Crystal structures were obtained of 5,6,8,9-tetrahydrodibenzoxamagnesecin (2a) and bis(2,6-di(methoxymethyl)phenyl)magnesium (4a).The extent of intramolecular coordination in these compounds as determined in the solid state, is used in the discussion of the influence of substituents on the Schlenk equilibrium parameters.Unusual penta- or hexa-coordination is encountered and explained as a consequence of intramolecular coordination.
