Structural characterization of tris(pyrazolyl)hydroborato and tris(2-pyridylthio)methyl lithium compounds: Lithium in uncommon trigonal pyramidal and trigonal monopyramidal coordination environments

Zinc and Magnesium Catalysts for the Hydrosilylation of Carbon Dioxide

“…Specifically, the magnesium and zinc hydride compounds, [κ 3 -Tism Pr i Benz ]ZnH and [Tism Pr i Benz ]­MgH, also undergo rapid hydride abstraction by B­(C 6 F 5 ) 3 to afford {[Tism Pr i Benz ]­Zn}-[HB(C 6 F 5 ) 3 ] ( 4 ) and {[Tism Pr i Benz ]­Mg}­[HB(C 6 F 5 ) 3 ] ( 5 ), respectively. The molecular structures of {[Tism Pr i Benz ]­M}[HB(C 6 F 5 ) 3 ] (M = Zn, Mg) have been determined by X-ray diffraction (Figures and ), which demonstrates that the compounds possess uncommon trigonal monopyramidal , geometries and exist as ion pairs. In this regard, the structure of {[Tism Pr i Benz ]­Mg}­[HB­(C 6 F 5 ) 3 ] is in marked contrast to that of the related compound, [To M ]­MgHB(C 6 F 5 ) 3 , which does not exist as an ion pair but rather possesses a distinct Mg–H–B interaction .…”

Isolable iodosylarene and iodoxyarene adducts of Co and their O-atom transfer and C–H activation reactivity

“…Starting materials and ligands were synthesized according to previously reported procedures with slight modifications in some cases (see ESI † ). 39 – 45 Treatment of the previously reported NaTp Ad,Me or KTp t Bu ligands with Co(MeCN) 6 (OTf) 2 in dichloromethane (DCM) yielded complexes [Co( ii )Tp Ad,Me (OTf)] ( 4 ) and [Co( ii )Tp t Bu (OTf)] ( 5 ) (OTf = trifluoromethanesulfonate) in 76% and 64% yield as bright blue crystalline solids. The 1 H NMR spectra of these complexes confirm overall C 3 -symmetry in solution with shifted resonances characteristic of paramagnetic species.…”

Tris[(1-isopropylbenzimidazol-2-yl)dimethylsilyl]methyl metal complexes, [TismPriBenz]M: a new class of metallacarbatranes, isomerization to a tris(N-heterocyclic carbene) derivative, and evidence for an inverted ligand field

“… 23 , 24 Trigonal monopyramidal coordination is not common for lithium, but a similar coordination environment is observed for tris(2-pyridylthio)methyllithium, [Tptm]Li. 3 , 25 An interesting difference between [Tism Pr i Benz ]Li and [Tptm]Li, however, pertains to the geometry at the bridgehead carbon atom. Specifically, the [CSi 3 ] moiety of [Tism Pr i Benz ]Li adopts a much greater degree of planarity ( Table 1 ) than does the [CS 3 ] moiety of [Tptm]Li, as indicated by the fact that the sum of the Si–C–Si angles of [Tism Pr i Benz ]Li (355.8°) 26 is much closer to 360° than is the sum of the S–C–S angles of [Tptm]Li (345.2°).…”

“…Atranes comprise an interesting class of molecules in which two bridgehead atoms are joined by three three-atom linkers, thereby resulting in a tricyclic motif. 1 – 3 A relatively recent development in this area is concerned with the synthesis of metallacarbatranes that feature transannular M–C interactions. 4 Such compounds are of interest because the M–C bond corresponds to an M–X interaction, in contrast to the transannular M←L 4 , 5 or M→Z 4 , 6 dative bonds that are more commonly encountered in atranes ( Fig.…”

“…1 ). 7 , 8 For example, we have recently employed tris(2-pyridylthio)methyl ([Tptm]) 3 , 9 and tris(1-methylimidazol-2-ylthio)methyl ([Titm Me ]) 10 as ligands for the construction of metallacarbatranes, 11 and have demonstrated that the nature of the heterocyclic nitrogen donor has an impact on the structure of the carbatrane. 10 Since a common feature of these ligands is the attachment of the heterocycles to the carbon bridgehead via a sulfur atom, we considered it worthwhile to investigate a different type of linker.…”