Cubane and step-form structures of dilithium bis(aryloxy)phosphines

Abstract

The lithium complexes RP(3,5-tBu2C6H2OLi)2(THF)4, where R = Ph or i Pr, (R[OPO]Li2)2(THF)4, synthesized by reaction of the 2-bromo-4,6-di-tert-butylphenol with BuLi and the appropriate dichlorophosphine, possess solid state structures composed of lithium oxide tetragons arranged in a step-form or face sharing half-cubane arrangements. Incorporation of excess lithium aryloxide results in the formation of complexes that display an extended step-form structure, [Ph[OPO]Li2(ArOLi)]2, or a distorted cubane arrangement of tetragons, [iPr[OPO]Li3Cl(ArOLi)](THF)3.

Synthesis and Structural Characterization of Lithium and Iron Complexes Containing a Chelating Phenolate Phosphane Ligand

“…The observed 31 P NMR chemical shift at approximately -32 ppm from these experiments is comparable to those acquired with well-defined compounds prepared in DME or THF solutions. [18,20] Attempts to grow crystals of these solvent-free lithium complexes, however, led to amorphous precipitates, the 1 H NMR spectra of which are unfortunately featureless. Similar reactions were conducted in diethyl ether solutions, which also led to the clean formation of the anticipated dilithium derivative as indicated by 31 Ph and NaH in DME gave Na(HL Ph )(DME) 2 .…”

“…[18,20] In this contribution, we describe the syntheses and structures of diethyl ether adducts of Li(HL Ph ) and Li 2 L Ph ; the structural motif of these molecules is notably distinct from those of Li 2 (L Ph )(DME) 2 [18] and {Li 2 (L Ph )(THF) 2 } 2 . [20] Utilization of the established Group 1 complexes of [L Ph ] 2-for the preparation of iron derivatives is also reported. Investigation of phenolate complexes of iron is intriguing in view of their relevance to metalloprotein chemistry.…”

Yttrium Complexes of Arsine, Arsenide, and Arsinidene Ligands

“…[15] At erminally bonded phosphinidene ligand remains ak ey target in rare-earth metal chemistry,a lthough auranium complex of such aligand was reported recently. [16] Thechemistry of rare-earth metal complexes with arsenic donor ligands is almost entirely unexplored:arsenide (R 2 As À ) complexes are rare, [17][18][19][20][21][22] and arsinidene (RAs 2À )l igands are unknown in rare-earth metal chemistry.T he development of synthetic routes to rare-earth metal arsinidene complexes could lead to more novel reactivity,s uch as arsinidene transfer, and would also furnish new opportunities for using arsenic ligands to influence the electronic structure and magnetism of lanthanide(III) complexes.W ith these possibilities in mind, we now report the first example of arare-earth metal arsinidene complex.Our strategy involved the initial synthesis of ap rimary arsine complex of yttrium to establish the metal-arsenic bond, followed by deprotonation of the {YAsH 2 R} unit to give corresponding yttrium-arsenide and yttrium-arsinidene complexes.T hus,a dding one stoichiometric equivalent of mesitylarsine to Cp' 3 Yi nt oluene led to the formation of [Cp' 3 Y{As(H) 2 Mes}] (1)( Cp' = h 5 -C 5 H 4 Me,M es = mesityl), which was crystallized as colorless blocks in 88 %y ield (Scheme 1). To obtain the yttrium arsenide complex, 1 was dissolved in toluene and one equivalent of nBuLi was added.…”

“…[15] At erminally bonded phosphinidene ligand remains ak ey target in rare-earth metal chemistry,a lthough auranium complex of such aligand was reported recently. [16] Thechemistry of rare-earth metal complexes with arsenic donor ligands is almost entirely unexplored:arsenide (R 2 As À ) complexes are rare, [17][18][19][20][21][22] and arsinidene (RAs 2À )l igands are unknown in rare-earth metal chemistry.T he development of synthetic routes to rare-earth metal arsinidene complexes could lead to more novel reactivity,s uch as arsinidene transfer, and would also furnish new opportunities for using arsenic ligands to influence the electronic structure and magnetism of lanthanide(III) complexes.W ith these possibilities in mind, we now report the first example of arare-earth metal arsinidene complex.…”

“…[18][19][20][21][22] Arange of synthetic routes have been employed to access secondary arsenide complexes,including,for example,deprotonation of Ph 2 AsH by the lutetium-lithium methyl complex [Cp 2 Lu(m-CH 3 ) 2 Li-(tmeda)] (tmeda = N,N,N',N'-tetramethylethylenediamine), which resulted in the formation of the arsenide-bridged species [Cp 2 Lu(m-AsPh 2 ) 2 Li(tmeda)]. [17] Activation of AsÀAs bonds by samarium(II) reduction has also been used to access arsenide complexes such as [Cp* 2 SmAsPh 2 ], which features aterminally bonded [Ph 2 As] À arsenide ligand. [19,20] Lanthanide(II) arsenide and arsolyl complexes can be accessed by salt metathesis reactions of LnI 2 with alkali-metal arsenide salts; for example,M es 2 AsK reacts with SmI 2 to give trans-[(Mes 2 As) 2 Sm(thf) 4 ].…”