Palladium-catalyzed formation of secondary and tertiary amines from aryl dihalides with air-stable ferrocenyl tri- and diphosphines: Synthesis and X-ray structure of efficient catalysts beyond [PdCl2(DPPF)]

A general diastereoselective synthesis of highly functionalized ferrocenyl ambiphiles enabled on a large scale by electrochemical purification

A diastereoselective modification of tert-butylated ferrocenes leads to highly functionalized constrained ambiphiles (P,B or N,B) and hybrids (P,N or P,P′) on a multigram scale by a smart electrochemical purification.

Gold(I) Complexes of Ferrocenyl Polyphosphines: Aurophilic Gold Chloride Formation and Phosphine-Concerted Shuttling of a Dinuclear [ClAu···AuCl] Fragment

A smart steric control of the metallocene backbone in bis- and poly(phosphino)ferrocene ligands favors intramolecular aurophilic interactions between [AuCl] fragments in polynuclear gold(I) complexes. We synthesized and characterized by multinuclear NMR and X-ray diffraction analysis mono-, di-, and polynuclear gold complexes of constrained ferrocenyl diphosphines, which bear either bulky tert-butyl groups or more flexible siloxane substituents at the cyclopentadienyl rings. The complexes meso-1,1'-bis(diphenylphosphino)-3,3'-di-tert-butylferrocene (4-m), rac-1,1'-bis[bis(5-methyl-2-furyl)phosphino]-3,3'-di-tert-butylferrocene (5-r), and rac-1,1'-bis(diphenylphosphino)-3,3'-bis[(tri-iso-propylsilyl)oxy]ferrocene (6-r) were used to form dinuclear gold complexes. Coordination of tert-butylated ferrocenyl phosphines generated aurophilic interactions in the corresponding dinuclear gold complexes, contrary to gold(I) complexes reported with 1,1'-bis(diphenylphosphino)ferrocene. The structurally related tetraphosphine 1,1',2,2'-tetrakis(diphenylphosphino)-4,4'-di-tert-butylferrocene (11) also gave access to mononuclear, dinuclear, and the original trinuclear gold chloride aurophilic complexes in which 14e^- to 16e^- gold centers coexist. In such complexes, nonbonded ("through-space") ³¹P-³¹P' nuclear spin couplings were evidenced by high-resolution NMR. In these interactions nuclear spin information is transferred between the lone-pair electron of an uncoordinated phosphorus P and a phosphorus P' that is involved in a σ covalent bond Au-P'. The dinuclear aurophilic complex displayed a concerted shuttling of its [ClAu···AuCl] fragment between the four phosphorus donors of the tetraphosphine ligand. Thus, an aurophilic Au···Au bond, which is assumed to be a weak energy interaction, can be conserved within a dynamic shuttling process at high temperature involving an intramolecular coordination-decoordination process of digold(I) at phosphorus atoms.

Modular functionalized polyphosphines for supported materials: previously unobserved31P-NMR «through-space» ABCD spin systems and heterogeneous palladium-catalysed C–C and C–H arylation

Functionalized modular polyphosphines introduce a conceptual novelty in controlling both implantation and conformation of donors in immobilized catalysts.