Catalytic applications of small bite-angle diphosphorus ligands with single-atom linkers

Diphosphorus ligands connected by a single atom (R2PEPR2; E = CR2, CCR2and NR) give chelating ligands with very small bite-angles as well as enable access to other properties such as bridging modes and hemilability. ThisPerspectivereviews the properties of diphosphorus ligands featuring a single-atom linker and their applications in catalysis, including transformations of alkenes and transfer hydrogenation and hydrogen-borrowing reactions.</p

Rare Earth and Actinide Complexes

The rare earth metals (scandium, yttrium, lanthanum and the subsequent 4f elements) and actinides (actinium and the 5f elements) are vital components of our technology-dominated society.[...

Synergic deprotonation generates alkali-metal salts of tethered fluorenide NHC ligands co-complexed to alkali metal amides

Synergic combinations of alkali-metal hydrocarbyl/amide reagents were used to synthesise saturated N-heterocyclic carbene (NHC) ligands tethered to a fluorenide anion through deprotonation of a spirocyclic precursor, whereas conventional bases were not successful. The Li2 derivatives displayed a bridging amide between two Li atoms within the fluorenide-NHC pocket, whereas the Na2 and K2 analogues displayed extended solid-state structures with the fluorenide-NHC ligand chelating one alkali metal centre

Synthesis and Reactivity of Fluorenyl-Tethered N-heterocyclic Stannylenes

N-Heterocyclic stannylenes containing a functionalised donor arm have been synthesised using a transamination strategy from [Sn{N(SiMe3)2}2] and fluorenyl-tethered diamines.</p

Unexpected Multiple Coordination Modes in Silyl-Bridged Bis(phosphinine) Complexes

The bis­(phosphinine) [bis­{3-methyl-6-(tri­methyl­silyl)­phosphinine-2-yl}­dimeth­yl­silane] (1) was synthesized and its coordination chemistry explored. Molybdenum and chromium carbonyl complexes were crystallographically characterized featuring 1 bound η6 through one phosphinine [Mo­(CO)3­(η6-1)] (2Mo), η6 through both phosphinines to two metal centers [{M­(CO)3}2­(μ-η6:​η6-1)] (3M2, M = Cr, Mo), and chelating with η1 coordination through both phosphines [M­(CO)4­(κ:η1:​η1-1)] (4M, M = Cr, Mo). However, only 3Mo2 could be isolated analytically pure. Heating species 3Mo2 in the presence of [Pd­(COD)­Cl2] removed one CO ligand and generated [{Mo­(CO)2}­(μ-κ:​η1η6-η6-1)­{Mo­(CO)3}] (5), which is the first crystallized example of a bis­(phos­phinine) featuring chelating η1 and η6 coordination, as well as a metal center bound to two phosphinines with different binding modes. In order to enforce a chelating bis-η1 binding mode, the Ru complex [Ru­(Cp*)­(Cl)­(κ:η1:η1-1)] (6) was prepared, demonstrating that judicious choice of metal fragment can dictate the coordination mode of a bis­(phos­phinine). Conversion of 6 to the hydride species [Ru­(Cp*)­(H)­(κ:η1:​η1-1)] (7) afforded the first crystallographically characterized example of a complex with both phosphinine and hydride ligands at the same metal center

An indenide-tethered N-heterocyclic stannylene

The structure of (μ-1κN:2(η2),κ2N,N′-(2-{[2,6-bis(propan-2-yl)phen­yl]aza­nid­yl}eth­yl)[2-(1H-inden-1-yl)eth­yl]aza­nido)(1,4,7,10,13,16-hexa­oxa­cyclo­octa­dec­ane-1κ6O)lithiumtin, [LiSn(C8H16O4)(C25H31N2)], at 100 K has monoclinic (P21/n) symmetry. Analysis of the coordination of the Sn to the indenyl ring shows that the Sn inter­acts in an η2 fashion. A database survey showed that whilst this coordination mode is unusual for Ge and Pb compounds, Sn displays a wider range of coordination modes to cyclo­penta­dienyl ligands and their derivatives