A “Push–Pull” Stabilized Phosphinidene Supported by a Phosphine‐Functionalized β‐Diketiminato Ligand

Abstract

The use of a bis(diphenyl)phosphine functionalized β‐diketiminato ligand, [HC{(CH 3 )C} 2 {( ortho ‐[P(C 6 H 5 ) 2 ] 2 C 6 H 4 )N} 2 ] − (PNac), as a support for germanium(II) and tin(II) chloride and phosphaketene compounds, is described. The conformational flexibility and hemilability of this unique ligand provide a versatile coordination environment that can accommodate the electronic needs of the ligated elements. For example, chloride abstraction from [(PNac)ECl] (E=Ge, Sn) affords the cationic germyliumylidene and stannyliumylidene species [(PNac)E] + in which the pendant phosphine arms associate more strongly with the Lewis acidic main group element centers, providing further electronic stabilization. In a similar fashion, chemical decarbonylation of the germanium phosphaketene [(PNac)Ge(PCO)] with tris(pentafluorophenyl)borane affords a “push–pull” stabilized phosphinidene in which one of the phosphine groups of the ligand backbone associates with the low valent phosphinidene center.

Adducts of the Parent Boraphosphaketene H2BPCO and their Decarbonylative Insertion Chemistry

“…[6] This ability makes phosphaketenes excellent reagents for forming both single and multiple phosphorus À element bonds. [6,7] The generation of the first boron-functionalized phosphaethynolates was reported in 2017, but their definitive isolation and structural confirmation was provided by Goicoechea and co-workers in 2018. [8] Thus far only a handful of boron-functionalized phosphaethynolates/phosphaketenes (i.e.…”

Reactions of Late First‐Row Transition Metal (Fe‐Zn) Dichlorides with a PGeP Pincer Germylene

“…[12] To improve this situation we have recently synthesized germylene E (Figure 1), [13] which is based on the dipyrromethane scaffold,a nd we have already proven that it forms stable d 10 metal derivatives. [13,17] Although two additional metal-free PGeP germylenes have been recently communicated (D and F in Figure 1), germylene D has only been used as al igand in nickel(0) complexes, [14] and no reaction with aT Mc omplex has yet been reported for germylene F. [18] We now report the reactivity of germylene E with the lightest metal dichlorides of groups 8-12 of the periodic table (Fe-Zn). These reactions have afforded stable chloridogermyl PGeP pincer complexes of earth-abundant metalsw hose metal atoms are in unstrained square planar (Fe II ,C o II ,N i II )o rt etrahedral (Cu I ,Z n II )l igand environments.…”

“…No single crystals of compound 1 could be obtained, but an X‐ray diffraction (XRD) study on a crystal of compound 2 (data taken at 157 K) revealed that it was constituted by square planar cobalt(II) molecules in which the metal atom is attached to a chloridogermyl PGeP pincer ligand (Figure 2) with a Co−Ge distance of 2.2519(5) Å. This molecule is reminiscent of the only previously known square planar complex derived from germylene E , that is [PdCl{κ 3 P , Ge , P ‐GeCl(pyrmP i Pr 2 ) 2 CMe 2 }], which was prepared by treating the T‐shaped palladium(0) complex [Pd{κ 3 P , Ge , P ‐Ge(pyrmP i Pr 2 ) 2 CMe 2 }] with HCl or, alternatively, by reacting germylene E with [PdCl 2 (MeCN) 2 ] [18] …”

“…No single crystals of compound 1 couldb eo btained, but an X-ray diffraction (XRD) study on ac rystal of compound 2 (data taken at 157 K) revealed that it was constituted by square planarc obalt(II) molecules in which the metal atom is attached to ac hloridogermyl PGeP pincerl igand ( Figure 2) with aC o À Ge distance of 2.2519 (5) .T his molecule is reminiscent of the only previously known square planar complex derived from germylene E,t hat is [PdCl{k 3 P,Ge,P-GeCl(pyrmPiPr 2 ) 2 CMe 2 }], which was prepared by treating the T-shaped palladium(0) complex [Pd{k 3 P,Ge,P-Ge(pyrmPiPr 2 ) 2 CMe 2 }] with HCl or,a lternatively,byr eacting germylene E with [PdCl 2 (MeCN) 2 ]. [18] Variable-temperaturem agnetic susceptibility studies were performedonc omplexes 1 and 2 (Supporting Information, Figure S17), not only to investigate their magnetic behavior but also to get more insights into their molecular structures (both compounds could be tetrahedral or squarep lanar). Figure 3 shows that the effective magnetic moment (m eff )o ft he iron(II) complex 1 is approximately 3.0 m B over aw idet emperature range (50-380 K), being smallera tT < 50 Kp robably due to thermald epopulation of zero-field split electronic states.…”

“…To improve this situation we have recently synthesized germylene E (Figure 1), [13] which is based on the dipyrromethane scaffold, and we have already proven that it forms stable d 10 metal derivatives [13, 17] . Although two additional metal‐free PGeP germylenes have been recently communicated ( D and F in Figure 1), germylene D has only been used as a ligand in nickel(0) complexes, [14] and no reaction with a TM complex has yet been reported for germylene F [18] …”