A Terminal Yttrium Phosphinidene

Abstract

Terminal, nondirectional ionic "multiple" bond interactions between group 15 elements and rare-earth metals (Ln) have remained a challenging target until present. Although reports on terminal imide species have accumulated in the meantime, examples of terminal congeners with the higher homologue phosphorus are yet elusive. Herein, we present the synthesis of the first terminal yttrium organophosphinidene complex, Tp tBu,Me Y(� PC 6 H 3 iPr 2 -2,6)(DMAP) 2 , according to a double-deprotonation sequence previously established for organoimides of the smaller rare-earth metals. Subsequent deprotonation of the primary phosphane H 2 PC 6 H 3 iPr 2 -2,6 (H 2 PAr iPr ) with discrete dimethyl compound Tp tBu,Me YMe 2 in the presence of DMAP under simultaneous methane elimination generated a terminal multiply bonded phosphorus. The primary phosphide intermediates Tp tBu,Me YMe(HPAr iPr ) and Tp tBu,Me YMe(HNPAr iPr )(DMAP) are isolable species and were also obtained and fully characterized for holmium and dysprosium. The Lewis acid-stabilized yttrium phosphinidene Tp tBu,Me Y[(μ 2 -PAr iPr )(μ 2 -Me)AlMe 2 ] was obtained by treatment of H 2 PAr iPr with Tp tBu,Me YMe(AlMe 4 ) but could not be converted into a terminal phosphinidene via cleavage of trimethylaluminum. The corresponding reaction of H 2 PAr iPr with Tp tBu,Me YMe(GaMe 4 ) led to adduct [GaMe 3 (PH 2 Ar iPr )] rather than to the formation of a yttrium phosphinidene. The yttrium−phosphorus interaction in the obtained organophosphide and phosphinidene complexes was scrutinized by 31 P/ 89 Y NMR spectroscopy and DFT calculations, unambiguously supporting the existence of multiple bonding.

Terminal dysprosium and holmium organoimides

“…Recent years have witnessed major progress in the field of rare-earth-metal (Ln) complexes with multiply bonded (dianionic) main-group ligands, most notably (organo)imide chemistry. 1–3 Upon closer inspection this is not all that surprising, since [LnNR] moieties display a favourable Pearson hard/hard match and enhanced steric/electronic variability through the imido substituent R, 4 compared to other fragments such as [LnO], 5 [LnPR], 6 or [Ln=CR 2 ]. 7 Of particular interest have been the synthesis of terminal rare-earth-metal imides 8–15 and a fundamental understanding of the Ln–imido bonding as well as reactivity, 16 and in particular small-molecule-activation scenarios.…”

f-Element heavy pnictogen chemistry

“…Very recently, Sirsch, Anwander and co-workers reported the synthesis and molecular structure of the first terminal yttrium phosphinidene complex, Scheme 13. 61 The reactions of H 2 PDipp with the lanthanide dimethyl complexes [Ln(Tp t Bu,Me )(Me) 2 ] (Ln = Y, Dy, Ho; Tp t Bu,Me = HB(2-Me-4- t Bu-N 2 C 3 H) 3 ) afforded the corresponding phosphide complexes [(Tp t Bu,Me )Ln(Me)(HPDipp)] ( 38Ln , Ln = Y, Dy, Ho). Addition of DMAP to 38Ln gave the corresponding DMAP adducts [(Tp t Bu,Me )Ln(Me)(HPDipp)(DMAP)] ( 39Ln , Ln = Y, Dy, Ho); addition of a further equivalent of DMAP to 38Y produced [Y(Tp t Bu,Me )(PDipp)(DMAP) 2 ] ( 40 ).…”

“…More recently, Roesky and co-workers found that yellow arsenic (As 4 ) is also a useful source to introduce polyarsenic ligands to lanthanides. Due to the unstable nature of this As 4 allotrope under ambient conditions, the authors used freshly-prepared As 4 in solution to react with the divalent precursor [Sm(DippForm) 2 (THF) 2 ]; after workup, red crystals of the cyclo -As 4 complex [{Sm(DippForm) 2 } 2 (μ-η 4 :η 4 -As 4 )] (93), 61 Scheme 29 , were obtained as a minor product, which is essentially isostructural to the lanthanide cyclo -P 4 complex 48. Unfortunately, the presence of non-removable impurities hampered further characterisation on 93 because of the instability of As 4 in solution.…”

Rare-Earth Metal Phosphinidene Complexes: A Trip from Bridging One to Terminal One

“…But with the strong interest in this field, we can expect that the terminal phosphinidene complexes of other rare-earth metals will appear shortly as what we have witnessed in the chemistry of the terminal rare-earth metal imido complexes . Interestingly, after we submitted this Account, Anwander and co-workers reported an yttrium terminal phosphinidene complex . We can also expect more interesting stoichiometric reactivity and catalytic reactivity when the library of the rare-earth metal phosphinidene complexes continues to grow.…”