A Phosphine Functionalized β‐Diketimine Ligand for the Synthesis of Manifold Metal Complexes

Abstract

Ab is(diphenyl)-phosphine functionalized b-diketimine (PNac-H) was synthesizeda saflexible ligand for transition metal complexes.T he newly designed ligand features symmetrically placed phosphine moieties around a b-diketimine unit, forming aP NNP-type pocket. Due to the hard and soft donora toms (N vs. P) the ligand can stabilize various coordination polyhedra.Acomplete series rangingf rom coordination numbers2to 6w as realized. Linear,t rigonal planar,s quare planar,t etrahedral, square pyramidal,a nd octahedral coordination arrangements containing the PNacligand around the metal centerw ere observed by using suitable metal sources. Hereby, PNac-H or its anion PNac À acts as mono-, bi-and tetradendate ligand. Such ab road flexibility is unusualf or ar igid tetradentate system.T he structural motifs were realized by treatment of PNac-H with as eries of late transitionm etal precursors, for example, silver,g old, nickel, copper, platinum, and rhodium. The new complexes have been fully characterizedb ys ingle crystal X-ray diffraction, NMR,I R, UV/Vis spectroscopy,m ass spectrometry as well as elemental analysis. Additionally,s elected complexes were investigated regarding their photophysical properties. Thus,P Nac-H provedt ob ea ni deal ligand platform for the selectivec oordination and stabilization of variousm etal ions in diversepolyhedra and oxidation states. sis [8, 19-23] as well as the activation of small molecules. [13, 24-26] In this regard, b-diketiminate ligandsh ave been proven capable of supporting metal ions in an umber of oxidation states as well as chemical environments. [27] Especially,t he stabilization of sub-valent andu ncommon oxidation states,f or example, Fe I , [26] Al I , [24, 27, 28] Ga I , [27] Si II , [29] Ge I , [30] and Mg I species, [31, 32] has been an achievement of supporting b-diketiminatel igand systems. Hereby,t he scaffold can be easily modified by varying the corresponding N-substituents,w hicha re adjustable regarding their steric demand, electronic properties as well as the introductiono fa dditional functionalities. [15] Thiso ffers ah igh degreeo fc ontrol for task-specific adjustments, for example, the kinetic stabilization of sub-valent and reactive metal species via sterically demanding substituents, [31, 33, 34] or an enhanced reactivity of the resulting metal complexes. [35, 36] In general,ab-diketiminate ligand provides am onoanionic, bidentate support for metal ions, [15] yet the introduction of additional heteroatom donor sites to the b-diketiminate scaffold allowst he extension to more complex coordination motifs,a higherd egree of metal stabilization as wella st he potential formation of heterobimetallicc omplexes.H erein, the design of the ligand plays ac rucial role in promoting or enforcingspecific arrangements. The introduction of additional side groups to a b-diketimines ystemh as already been investigatedapplying O-donora nd S-donorf unctionalities (Figure1), enabling the formation of multidentate ONNO and SNNS pockets, respectively.T hese bifunctionall ...

A Phosphine‐ß‐diketiminate Nickel(I)‐Complex for Small Molecule Activation

“…The phosphine functionalized ß-diketimine ligand (PNac-H) was obtained by a two-step synthesis route, as previously reported by our group. [32,33] Subsequent treatment with Ni(0) precursor [Ni(cod) 2 ] resulted in the formation of nickel(I) complex [PNac-Ni] (1) by a redox reaction (Scheme 1). In complex 1 the metal ion is surrounded by a tetradentate PNNP type pocket, which effectively protects the subvalent Ni(I) center.…”

Interplay between β-Diimino and β-Diketiminato Ligands in Nickel Complexes Active in the Proton Reduction Reaction

“…Symmetrical κ 4 -P 2 N 2 ligands derived from β-diketiminate are scarce in the literature, despite the well-known capacity of both BDK and phosphine groups to stabilize coordination complexes. , Other examples include only one phosphine arm connected to the BDK ligand. , HBDI and PhBDI ligands in Figure and Scheme are two novel tetradentate ligands with two nitrogen and two phosphorous donors that differ on the substituent of the α-C position (H for HBDI and Ph for PhBDI). The synthesis of the ligands HBDI and PhBDI was performed through two consecutive condensation steps in oxygen and moisture free conditions.…”

Bi- and trinuclear coinage metal complexes of a PNNP ligand featuring metallophilic interactions and an unusual charge separation

“…The known dpfam − ligand 48 was obtained with a new synthetic protocol adapted from related PNNP ligand synthesis. [53][54][55] It directly leads to the potassium salt Kdpfam which can be readily isolated and applied as a versatile precursor. Specifically, N,N′-bis(2-fluorophenyl)formamidine was reacted with potassium diphenyl phosphide in toluene to yield the desired product in excellent yield (see ESI; † Scheme 1).…”