Synthese und Struktur von Sr6P8‐Polyedern in gemischten Phosphaniden/Phosphandiiden des Strontiums

Synthesis and Structures of Sr₆P₈ Polyhedra in Mixed Phosphanides/Phosphandiides of Strontium The strontiation of H₂PSiⁱPr₃ ( 1 ) with (THF)₂Sr[N(SiMe₃)₂]₂ in THF yields colorless tetrakis(tetrahydrofuran‐O)strontium bis(triisopropylsilylphosphanide) ( 3 ). The central alkaline earth metal atom has an octahedral environment with the phosphanide ligands in trans position. The homometalation in toluene leads to the elimination of 1 and THF. Cooling of this solution gives crystals of colorless tetrakis(tetrahydrofuran‐O)hexastrontium‐tetrakis(triisopropylsilylphosphanide)‐tetrakis(triisopropylsilylphosphandiide) ( 4 ). The equimolar reaction of H₂PSi^tBu₃ ( 2 ) with (THF)₂Sr[N(SiMe₃)₂]₂ in toluene yields in the first step heteroleptic dimeric {(Me₃Si)₂NSr(THF)₂[P(H)Si^tBu₃]}₂ ( 5 )₂. This compounds monomerizes in THF to (Me₃Si)₂N–Sr(THF)₄[P(H)Si^tBu₃] ( 6 ), which forms an equilibrium with the homoleptic dismutation products (THF)₂Sr[N(SiMe₃)₂]₂ and (THF)₄Sr[P(H)Si^tBu₃]₂ ( 7 ). Compound ( 5 )₂ undergoes a intramolecular strontiation and bis(tetrahydrofuran‐O)hexastrontium‐tetrakis[tri(tert‐butyl)silylphosphanide]‐tetrakis[tri(tert‐butyl)silylphosphandiide] ( 8 ) is isolated. The central Sr₆P₈‐polyhedra of 4 and 8 are very similar.     

Synthese,spektroskopische Charakterisierung und Molekülstrukturen ausgewählter Lewis‐Basen‐Addukte der Alkalimetall‐tri(tert‐butyl)silylphosphanide

Synthesis, Spectroscopic Characterization, and Molecular Structures of Selected Lewis‐Base Adducts of the Alkali Metal Tri(tert‐butyl)silylphosphanides The metalation of tri(tert‐butyl)silylphosphane with butyllithium and the bis(trimethylsilyl)amides of sodium, potassium, and rubidium yields quantitatively the corresponding alkali metal tri(tert‐butyl)silylphosphanides, which crystallize after addition of appropriate Lewis‐bases as dimeric (DME)LiP(H)SitBu₃ ( 1 ), chain‐like (DME)NaP(H)SitBu₃ ( 2 ), monomeric ([18]Krone‐6)KP(H)SitBu₃ ( 3 ), and dimeric (TMEDA)_1.5RbP(H)SitBu₃ ( 4 ). The reaction of H₂PSitBu₃ with cesium bis(trimethylsilyl)amide at room temperature gives monocyclic and tetrameric cesium tri(tert‐butyl)silylphosphanide ( 5 ) with two additional coordinated CsN(SiMe₃)₂ molecules. At 80 °C this complex reacts with excess of phosphane to the tetrameric toluene adduct (η⁶‐Toluol)CsP(H)SitBu₃ ( 6 ) which contains a central Cs₄P₄‐heterocubane fragment. The constitution of these compounds was verified by X‐ray structure determinations.     

Strukturen zweifach metallierter Derivate von 3, 3‐Dimethyl‐1, 5‐bis(trimethylsilyl)‐1, 5‐diaza‐pentan mit Lithium und Aluminium sowie zweier Donor‐substituierter Digallane

Structural Characterization of Bis(metallated) Derivatives of 3, 3‐Dimethyl‐1, 5‐bis(trimethylsilyl)‐1, 5‐diaza‐pentane with Lithium and Aluminum and of two Donor‐substituted Digallanes The diaminopropane derivative Me₂C[CH₂N(H)SiMe₃]₂ is metallated with n‐butyllithium and lithium tetrahydridoaluminate to obtain Me₂C[CH₂N(Li)SiMe₃]₂ and Me₂C[CH₂N(Li)SiMe₃][CH₂N(AlH₂)SiMe₃], respectively. Both compounds exhibit a central eight‐membered ring, Li₄N₄ or Li₂Al₂N₄. Me₂C[CH₂N(Li)SiMe₃]₂ reacts with Ga₂Cl₄ · 2dioxane under formation of the corresponding tetra(amino)digallane. This is monomeric, in contrast to a dimeric tetraalkoxy‐substituted digallane, Ga₄O^tBu₈. All compounds were characterized by single crystal X‐ray crystallography.     

Synthese und Strukturen von Yttrium‐tris[bis(trimethylsilyl)phosphanid] und 1, 1', 3, 3'‐Tetrakis(trimethylsilyl)yttrocen‐tri(tert‐butyl)silylphosphanid

The metalation of HP(SiMe₃)₂ with Y[CH(SiMe₃)₂]₃ gives the homoleptic {Y[P(SiMe₃)₂]₃}₂ (1) which crystallizes from toluene in the monoclinic space group P2₁/c. The yttrium atoms are in a distorted tetrahedral environment with Y‐P bond lengths of 267.7 and 284.8 pm to the terminal and bridging substituents, respectively. The metathesis reaction of [1, 3‐(Me₃Si)₂C₅H₃]₂YCl with KPSitBu₃ yields (tetrahydrofuran‐O)‐1, 1', 3, 3'‐tetrakis(trimethylsilyl)yttrocene‐tri(tert‐butyl)silylphosphanide ( 2 ). The molecular structure of 2 in solution was deduced by NMR spectroscopy and X‐ray crystallography. The coupling constants ¹J(Y, P) and ¹J(P, H) show values of 144.0 Hz and 201.0 Hz, respectively.     

Komplexchemie P‐reicher Phosphane und Silylphosphane. XXII. Die Bildung von [η2‐{tBu–P=P–SiMe3}Pt(PR3)2]aus (Me3Si)tBuP–P=P(Me)tBu2 und [η2‐{C2H4}Pt(PR3)2]

Coordination Chemistry of P‐rich Phosphanes and Silylphosphanes. XXII. The Formation of [η²‐{^tBu–P=P–SiMe₃}Pt(PR₃)₂] from (Me₃Si)^tBuP–P=P(Me)^tBu₂ and [η²‐{C₂H₄}Pt(PR₃)₂] (Me₃Si)^tBuP–P = P(Me)^tBu₂ reacts with [η²‐{C₂H₄}Pt(PR₃)₂] yielding [η²‐{^tBu–P=P–SiMe₃}Pt(PR₃)₂]. However, there is no indication for an isomer which would be the analogue to the well known [η²‐{^tBu₂P–P}Pt(PPh₃)₂]. The syntheses and NMR data of [η²‐{^tBu–P=P–SiMe₃}Pt(PPh₃)₂] and [η²‐{^tBu–P=P–SiMe₃}Pt(PMe₃)₂] as well as the results of the single crystal structure determination of [η²‐{^tBu–P=P–SiMe₃}Pt(PPh₃)₂] are reported.     

Über Bildung und Reaktionen der CH2Li‐Derivate von tBu2P–P=P(CH3)tBu2 und (Me3Si)tBuP–P=P(CH3)tBu2

Formation and Reactions of the CH₂Li‐Derivatives of ^tBu₂P–P=P(CH₃)^tBu₂ and (Me₃Si)^tBuP–P=P(CH₃)^tBu₂ With ⁿBuLi, (Me₃Si)^tBuP–P=P(CH₃)^tBu₂ ( 1 ) and ^tBu₂P–P=P(CH₃)^tBu₂ ( 2 ) yield (Me₃Si)^tBuP–P=P(CH₂Li)^tBu₂ ( 3 ) and ^tBu₂P–P=P(CH₂Li)^tBu₂ ( 4 ), wich react with Me₃SiCl to give (Me₃Si)^tBuP–P=P(CH₂–SiMe₃)^tBu₂ ( 5 ) and ^tBu₂P–P=P(CH₂–SiMe₃)^tBu₂ ( 6 ), respectively. With ^tBu₂P–P(SiMe₃)–P^tBuCl ( 7 ), compound 3 forms 5 as well as the cyclic products [H₂C–P(^tBu)₂=P–P(^tBu)–P^tBu] ( 8 ) and [H₂C–P(^tBu)₂=P–P(P^tBu₂)–P(^tBu)] ( 9 ). Also 3 forms 8 with ^tBuPCl₂. The cleavage of the Me₃Si–P‐bond in 1 by means of C₂Cl₆ or N‐bromo‐succinimide yields (Cl)^tBuP–P=P(CH₃)^tBu₂ ( 10 ) or (Br)^tBuP–P=P(CH₃)^tBu₂ ( 11 ), resp. With LiP(SiMe₃)₂, 10 forms (Me₃Si)₂P–P(^tBu)–P=P(CH₃)^tBu₂ ( 12 ), and Et₂P–P(^tBu)–P=P(CH₃)^tBu₂ ( 13 ) with LiPEt₂. All compounds are characterized by ³¹P NMR Data and mass spectra; the ylide 5 and the THF adduct of 4 additionally by X‐ray structure analyses.     

The Synthesis of tert‐Butyl(dichloromethyl)bis(trimethylsilyl)silane and (Dibromomethyl)ditert‐butyl(trimethylsilyl)silane and their Reactions with Organolithium Derivatives

tert‐Butyl(dichloromethyl)bis(trimethylsilyl)silane ( 4 ), prepared by the reaction of tert‐butylbis(trimethylsilyl)silane with trichloromethane and potassium tert‐butoxide, reacted with 2,4,6‐triisopropylphenyllithium (TipLi) (molar ratio 1 : 2) at room temperature to give (after hydrolytic workup) the silanol tBu(2,4,6‐iPr₃C₆H₂)Si(OH)–CH(SiMe₃)₂ ( 15 ). The formation of 15 is discussed as proceeding through the indefinitely stable silene tBu(2,4,6‐iPr₃C₆H₂)Si=C(SiMe₃)₂ ( 13 ), but attempts to isolate the compound failed. Treatment of (dibromomethyl)ditert‐butyl(trimethylsilyl)silane ( 7 ), made from tBu₂(Me₃Si)SiH, HCBr₃ and KOtBu, with methyllithium (1 : 3) at –78 °C afforded tBu₂MeSi–CHMeSiMe₃ ( 19 ); 7 and phenyllithium (1 : 3) under similar conditions gave tBu₂PhSi–CH₂SiMe₃ ( 20 ). The reaction paths leading to 15 , 19 and 20 are discussed. Reduction of 7 with lithium in THF produced the substituted ethylene tBu₂(Me₃Si)SiCH=CHSitBu₂SiMe₃ ( 21 ). For 21 the results of an X‐ray structural analysis are given.     

Synthesis and Structures of ansa‐Titanocene Complexes with Diatomic Bridging Units for Overall Water Splitting

The synthesis of a series of ansa‐titanocene dichlorides [Cp′₂TiCl₂] (Cp′=bridged η⁵‐tetramethylcyclopentadienyl) and the corresponding titanocene bis(trimethylsilyl)acetylene complexes [Cp′₂Ti(η²‐Me₃SiC₂SiMe₃)] is described. The ethanediyl‐bridged complexes [C₂H₄(C₅Me₄)₂TiCl₂] ( 2 ‐Cl₂) and [C₂H₄(C₅Me₄)₂Ti(η²‐Me₃SiC₂SiMe₃)] ( 2‐ btmsa; btmsa=η²‐Me₃SiC₂SiMe₃) can be obtained from the hitherto unknown calcocenophane complex [C₂H₄(C₅Me₄)₂Ca(THF)₂] ( 1 ). Furthermore, a heterodiatomic bridging unit containing both, a dimethylsilyl and a methylene group was introduced to yield the ansa‐titanocene dichloride [Me₂SiCH₂(C₅Me₄)₂TiCl₂] ( 3 ‐Cl₂) and the bis(trimethylsilyl)acetylene complex [Me₂SiCH₂(C₅Me₄)₂Ti(η²‐Me₃SiC₂SiMe₃)] ( 3 ‐btmsa). Besides, tetramethyldisilyl‐ and dimethylsilyl‐bridged metallocene complexes (structural motif 4 and 5 , respectively) were prepared. All ansa‐titanocene alkyne complexes were reacted with stoichiometric amounts of water; the hydrolysis products were isolated as model complexes for the investigation of the elemental steps of overall water splitting. Compounds 1 , 2 ‐btmsa, 2 ‐(OH)₂, 3 ‐Cl₂, 3 ‐btmsa, 4 ‐(OH)₂, 3 ‐alkenyl and 5 ‐alkenyl were characterised by X‐ray diffraction analysis.     

Studien zur Reaktion von [Me2AlP(SiMe3)2]2 mit basenstabilisierten Organogalliumchloriden und ‐hydriden

Investigations on the Reactivity of [Me₂AlP(SiMe₃)₂]₂ with Base‐stabilized Organogalliumhalides and ‐hydrides [Me₂AlP(SiMe₃)₂]₂ ( 1 ) reacts with dmap?Ga(Cl)Me₂, dmap?Ga(Me)Cl₂, dmap?GaCl₃ and dmap?Ga(H)Me₂ with Al‐P bond cleavage and subsequent formation of heterocyclic [Me₂GaP(SiMe₃)₂]₂ ( 2 ) as well as dmap?AlMe_xCl_3?x (x = 3 8 ; 2 3 ; 1 4 ; 0 5 ). The reaction between equimolar amounts of dmap?Al(Me₂)P(SiMe₃)₂ and dmap?Ga(t‐Bu₂)Cl yield dmap?Ga(t‐Bu₂)P(SiMe₃)₂ ( 6 ) and dmap?AlMe₂Cl ( 3 ). 2 – 8 were characterized by NMR spectroscopy, 2 and 6 also by single crystal X‐ray diffraction.     

1‐Azaallyl Complexes of NiII,PdII, and TiIII

The metal complexes [Ni{N(Ar)C(R)C(H)Ph}₂) ( 2 ) (Ar = 2,6‐Me₂C₆H₃, R = SiMe₃), [Ti(Cp₂){N(R)C(Bu^t)C(H)R}] ( 3 ), M{N(R)C(Bu^t)C(H)R}I [M = Ni ( 4 a ) or Pd ( 4 b )] and [M{N(R)C(Bu^t)C(H)R}I(PPh₃)] [M = Ni ( 5 a ) or Pd ( 5 b )] have been prepared from a suitable metal halide and lithium precursor of ( 2 ) or ( 3 ) or, alternatively from [M(LL)₂] (M = Ni, LL = cod; M = Pd, LL = dba) and the ketimine RN = C(Bu^t)CH(I)R ( 1 ). All compounds, except 4 were fully characterised, including the provision of X‐ray crystallographic data for complex 5 a .     

[Co(g5‐Me5C5)(g3‐tBu2PPCH–CH3)] aus [Co(g5‐Me5C5)(g2‐C2H4)2] und tBu2P–P=P(Me)tBu2

Coordination Chemistry of P‐rich Phosphanes and Silylphosphanes. XVII [1] [Co(g⁵‐Me₅C₅)(g³‐^tBu₂PPCH–CH₃)] from [Co(g⁵‐Me₅C₅)(g²‐C₂H₄)₂] and ^tBu₂P–P=P(Me)^tBu₂ [Co(η⁵‐Me₅C₅)(η³‐^tBu₂PPCH–CH₃)] 1 is formed in the reaction of [Co(η⁵‐Me₅C₅)(η²‐C₂H₄)₂] 2 with ^tBu₂P–P 4 (generated from ^tBu₂P–P=P(Me)^tBu₂ 3 ) by elimination of one C₂H₄ ligand and coupling of the phosphinophosphinidene with the second one. The structure of 1 is proven by ³¹P, ¹³C, ¹H NMR spectra and the X‐ray structure analysis. Within the ligand ^tBu₂P¹P²C¹H–CH₃ in 1 , the angle P1–P2–C1 amounts to 90°. The Co, P1, P2, C1 atoms in 1 look like a „butterfly”︁. The reaction of 2 with a mixture of ^tBu₂P–P=P(Me)^tBu₂ 3 and ^tBu–C?P 5 yields [Co(η⁵‐Me₅C₅){η⁴‐(^tBuCP)₂}] 6 and 1 . While 6 is spontaneously formed, 1 appears only after complete consumption of 5 .     

Tris[bis(trimethysilyl)amido]zinkate von Lithium und Calcium

Tris[bis(trimethylsilyl)amido]zincates of Lithium and Calcium Calcium-bis[bis(trimethylsilyl)amide] and Bis[bis(trimethylsilyl)amido]zinc yield in 1,2-dimethoxyethane quantitatively Calcium-bis{tris[bis(trimethylsilyl)- amido]zincate} · 3DME. When THF is chosen as a solvent, the two reactants and the zincate form a temperature-independent equilibrium, whereas in benzene no reaction occurs. The tris[bis(trimethylsilyl)amido]zincate anion displays characteristic ¹³C{¹H) and ²⁹Si{¹H] chemical shifts of 7 and ?8 ppm, respectively; the nature of the solvent, the cation and the complexating ligands don't influence the IR nor NMR data of the zincate anion and thus verify that [Ca(DME)₃]²⁺ and {Zn[N(SiMe_{3 2}]₃}^? appear as solvent separated ions, which is also confirmed by their insolubility in hydrocarbons.     

The Reactions of Carbon Monoxide with Silyl and Silenyl Lithium – Synthesis and Isolation of the First Stable Tetra‐Silyl Di‐Ketyl Biradical and 1‐Silaallenolate Lithium

Reactions of carbon monoxide (CO) with tBu₂MeSiLi and (E)‐(tBu₂MeSi)(tBuMe₂Si)C=Si(SiMetBu₂)Li?2 THF ( 4 ) were studied both experimentally and computationally. Reaction of tBu₂MeSiLi with CO in hexane yields the first stable tetra‐silyl di‐ketyl biradical [(tBu₂MeSi)₂COLi]^.₂ ( 3 ). Reaction of 4 with CO yields selectively and quantitatively the first reported 1‐silaallenolate, (tBu₂MeSi)(tBuMe₂Si)C=C=Si(SiMetBu₂)OLi?THF ( 5 ). Both 3 and 5 were characterized by X‐ray crystallography and biradical 3 also by EPR spectroscopy. Silaallenolate 5 reacts with Me₃SiCl to produce siloxy substituted 1‐silaallene (tBu₂MeSi)(tBuMe₂Si)C=C=Si(SiMetBu₂)OSiMe₃. The reaction of 4 with CO provides a new route to 1‐silaallenes. The mechanisms of the reactions of tBuMe₂SiLi and of 4 with CO were studied by DFT calculations.     

Synthesis and Characterization of trans‐PdII Trimethylsilylchalcogenolates

The trans‐bis(trimethylsilyl)chalcogenolate palladium complexes, trans‐[Pd(ESiMe₃)₂(PnBu₃)₂] [E = S ( 1 ) and Se ( 2 )] were synthesized in good yields and high purity by reacting trans‐[PdCl₂(PBu₃)₂] with LiESiMe₃ (E = S, Se), respectively. These complexes were characterized by ¹H, ¹³C{¹H}, ³¹P{¹H} (and ⁷⁷Se{¹H}) NMR spectroscopy and single‐crystal X‐ray analysis. The reaction of 2 with propionyl chloride led to the formation of trans‐[Pd(SeC(O)CH₂CH₃)₂(PnBu₃)₂] ( 3 ), a trans‐bis(selenocarboxylato) palladium complex and thus established a new method for the formation of this type of complex. Complex 3 was characterized by ¹H, ¹³C{¹H}, ³¹P{¹H} and ⁷⁷Se{¹H} NMR spectroscopy and a single‐crystal X‐ray structure analysis.     

Synthesis and Characterization of Heterobimetallic Tantalum–Rhodium and Tantalum–Iridium Complexes Connected by a Tantalacyclopentadiene Fragment

We report the synthesis of heterobimetallic Ta–Rh and Ta–Ir complexes bridged by a 2,5‐di‐tert‐butyltantalacyclopentadiene fragment. A mononuclear 2,5‐di‐tert‐butyltantalacyclopentadiene complex 2 was prepared by the reaction of (η²‐Me₃SiC≡CSiMe₃)TaCl₃(dme) ( 1 ) with excess amounts of 3,3‐dimethylbut‐1‐yne in the presence of AlCl₃. The tantalacyclopentadiene moiety of complex 2 served as a η⁴‐diene unit for coordinating the Rh and Ir centers; treatment of 2 with [M(μ‐Cl)(cod)]₂ (M = Rh and Ir; cod = cycloocta‐1,5‐diene) in toluene gave TaRh(μ‐C₄H₂^tBu₂)Cl₄(cod) ( 3 ) and [TaIr(μ‐C₄H₂^tBu₂)Cl₄]₂ ( 5 ), respectively. The X‐Ray diffraction study of 3 revealed a dative bond from an electron‐rich Rh toward an electron‐deficient Ta. Upon dissolving 3 in THF, [(thf)TaRh(μ‐C₄H₂^tBu₂)Cl₃]₂(μ‐Cl)₂ ( 4 ) was isolated together with free cycloocta‐1,5‐diene. When complex 5 was treated with 1,2‐bis‐(diphenylphosphino)ethane (dppe), a monomeric Ta–Ir complex, TaIr(μ‐C₄H₂^tBu₂)Cl₄(dppe) ( 6 ), was isolated. Ta–Rh and Ta–Ir heterobimetallic complexes 3 and 6 were reduced by a two‐electron process upon reaction with 2,3,5,6‐tetramethyl‐1,4‐bis(trimethylsilyl)‐1,4‐dihydropyrazine ( 7a : Si‐Me₄‐DHP) or 2,5‐dimethyl‐1,4‐bis(trimethylsilyl)‐1,4‐dihydropyrazine ( 7b : Si‐Me₂‐DHP) to afford the corresponding complexes TaM(μ‐C₄H₂^tBu₂)Cl₂(L) ( 8 : M = Rh, L = cod; 9 : M = Ir, L = dppe), where the metallacycle moiety was assigned to have a tantalacyclopentadiene fragment with a large contribution of a tantalacyclopentatriene canonical form.     

Lanthanide(II) Complexes of the Dihydrotriazinido Ligand [N{C(Ph)=N}2C(tBu)Ph]−

The potassium dihydrotriazinide K(L^Ph,tBu) ( 1 ) was obtained by a metal exchange route from [Li(L^Ph,tBu)(THF)₃] and KOtBu (L^Ph,tBu = [N{C(Ph)=N}₂C(tBu)Ph]). Reaction of 1 with 1 or 0.5 equivalents of SmI₂(thf)₂ yielded the monosubstituted Sm^II complex [Sm(L^Ph,tBu)I(THF)₄] ( 2 ) or the disubstituted [Sm(L^Ph,tBu)₂(THF)₂] ( 3 ), respectively. Attempted synthesis of a heteroleptic Sm^II amido‐alkyl complex by the reaction of 2 with KCH₂Ph produced compound 3 due to ligand redistribution. The Yb^II bis(dihydrotriazinide) [Yb(L^Ph,tBu)₂(THF)₂] ( 4 ) was isolated from the 1:1 reaction of YbI₂(THF)₂ and 1 . Molecular structures of the crystalline compounds 2 , 3· 2C₆H₆ and 4· PhMe were determined by X‐ray crystallography.     

Reaktionen von (tBu)2P?PP(Br)tBu2 mit LiP(SiMe3)2, LiPMe2 und LiMe,LitBu, LinBu

Reactions of (tBu)₂P? P?P(Br)tBu₂ with LiP(SiMe₃)₂, LiPMe₂ and LiMe, LitBu and LinBu The reactions of (tBu)₂P? P?P(Br)tBu₂ 1 with LiP(SiMe₃)₂ 2 yield (Me₃Si)₂P? P(SiMe₃)₂ 4 and P[P(tBu)₂]₂P(SiMe₃)₂ 5 , whereas 1 with LiPMe₂ 2 yields P₂Me₄ 6 and P[(tBu)₂]₂PMe₂ 7 . 1 with LiMe yields the ylid tBu₂P? P?P(Me)tBu₂ (main product) and [tBu₂P]₂PMe 15 . In the reaction of 1 with tBuLi [tBu₂P]₂PH 11 is the main product and also tBuP? P?P(R)tBu₂ 21 is formed. The reaction of 1 with nBuLi leads to [tBu₂P]₂PnBu 17 (main product) and tBu₂P? P?P(nBu)tBu₂ 22 (secondary product).     

Synthesis of ferrocene‐containing N‐aryloxo β‐ketoiminate lanthanide complexes and polymerization of ε‐caprolactone

The synthesis, characterization and ε‐caprolactone polymerization behavior of lanthanide amido complexes stabilized by ferrocene‐containing N‐aryloxo functionalized β‐ketoiminate ligand FcCOCH₂C(Me)N(2‐HO‐5‐Bu^t‐C₆H₃) (LH₂, Fc = ferrocenyl) are described. The lanthanide amido complexes [LLnN(SiMe₃)₂(THF)]₂ [Ln = Nd ( 1 ), Sm ( 2 ), Yb ( 3 ), Y ( 4 )] were synthesized in good yields by the amine elimination reactions of LH₂ with Ln[N(SiMe₃)₂]₃(µ‐Cl)Li(THF)₃ in a 1:1 molar ratio in THF. These complexes were characterized by IR spectroscopy and elemental analysis, and ¹H NMR spectroscopy was added for the analysis of complex 4 . The definitive molecular structures of complexes 1 and 3 were determined by X‐ray diffraction studies. Complexes 1 – 4 can initiate the ring‐opening polymerization of ε‐caprolactone with moderate activity. Copyright © 2011 John Wiley & Sons, Ltd.     

“Constrained geometry” catalysts of the rare-earth metals for the hydrosilylation of olefins

A series of yttrium and lutetium alkyl complexes [Ln(η⁵-C₅Me₄ZNR′-κN)(CH₂SiMe₃)(THF)_n] (Ln = Y, Lu) was prepared by reacting the tris(trimethylsilylmethyl) precursor [Ln(CH₂SiMe₃)₃(THF)₂] with different linked amino-cyclopentadienes of the type (C₅Me₄H)ZNHR′ (Z = SiMe₂, CH₂SiMe₂; R′ = tBu, Ph, C₆H₄-tBu-4, C₆H₄-nBu-4). The catalytic activity of these alkyl complexes in the hydrosilylation of 1-decene and styrene using PhSiH₃ as reagent was examined under standard conditions. A significant influence of the ligand structure on the catalytic property (turnover frequency, regioselectivity) was observed with the yttrium complex [Y(η⁵-C₅Me₄CH₂SiMe₂NtBu-κN)(CH₂SiMe₃)(THF)] being the most active for 1-decene hydrosilylation.     

Sulfur‐linked Phenolates as Ligands for the Syntheses of Low‐Nuclearity Iron(III) Complexes

Exploiting thiacalix 4 arene and sulfur‐bridged bisphenolates as ligands for bioinorganic studies involving iron(III) requires the prior development of synthetic routes (varying substituents and reaction conditions) to construct complexes with low nuclearities and accessible coordination sites, which was in the focus of this investigation. Treating p‐tert‐butylthiacalix 4 arene (H₄TC) and 1, 4‐dimethyl‐p‐tert‐butylthiacalix 4 arene (Me₂H₂TC) with Fe[N(SiMe₃)₂]₃ yielded in the formation of the iron(III) complexes [(Me₃SiTC)₂Fe₂] ( 1 ) and [(Me₂TC)₃Fe₂] ( 3 ), respectively. While 1 is a sandwich compound, in 3 one [Me₂TC]^2– unit is bridging two [Me₂TCFe]⁺ moieties. Employing thiobisphenolates as ligands it turned out, that in dependence on the residues R and the preparation method it is possible to selectively access sandwich, anionic or neutral complexes, which were shown to contain central high‐spin iron(III) atoms. The syntheses, structures, and electronic properties of three iron(III) bisphenolate complexes, [^ClL₂Fe]NEt₃H ( 4 ), [^MeLFeCl₂]NEt₃H ( 5 ), and [^tBuLFeCl(thf)] ( 7 ) are discussed.