Alternativ-Liganden. XXVI [1]. M(CO)4L-Komplexe (M  Cr,Mo, W) der Chelatliganden Me2ESiMe2(CH2)2E′Me2 (Me  CH3; E  P,As; E′  N,P, As)

Alternative Ligands. XXVI. M(CO)₄ L-Complexes (M ? Cr, Mo, W) of the Chelating Ligands Me₂ESiMe₂(CH₂)₂E′ Me₂ (Me ? CH₃; E ? P, As; E′ ? N, P, As) The reaction of M(CO)₄NBD (NBD = norbornadiene; M ? Cr, Mo, W) with the ligands Me₂ESiMe₂(CH₂)₂E′ Me₂ yields the chelate complexes (CO)₄M[Me₂ESiMe₂]) for E,E′ ? P, As, but not for E and /or E′ ? N. The NSi group is not suited for coordination because of strong (p-d)π-interaction. In the case of the ligands with E ? P or As and E′ ? N chelate complexes can be detected in the reaction mixture, but isolable products are complexes with two ligands coordinated via the E donor group. The new compounds are characterized by analytical and spectroscopic (IR, NMR, MS) investigations. The spectroscopic data are also used to deduce the coordinating properties of the ligands. X-ray diffraction studies of the molybdenum complexes (CO)₄Mo[Me₂ESiMe₂(CH₂)₂AsMe ₂] (E ? P, As) in accord with the observed coordination effects show only small differences between SiE and CE donor functions. Attempts to use the ligands Me₂ESiMe₂(CH₂)₂AsMe₂ (E ? P, As) for the preparation of Fe(CO)₃L complexes result in the fission of the SiE bonds and the formation of the binuclear systems Fe₂(CO)₆(EMe₂)₂ (E ? P, As) together with the disilane derivative [Me₂Si(CH₂)₂AsMe₂]₂.     

Alternativ-Liganden. VIII. Chelatkomplexe des Typs M(CO)4(Me2XGeMe2CH2X′Me2) (M = Cr,Mo, W; X,X′ = N,P, As; Me = CH3)

Chelate Complexes of the Type M(CO)₄(Me₂XGeMe₂CH₂X′Me₂) (M) = Cr, Mo, W; X, X′ = N, P, As; Me = CH₃) The ligands (Me₂)XGeMe₂CH₂X′Me₂ (M) = Cr, Mo, W) react with M(CO)₄norbor (norbor = Norbornadiene) (M = Cr, Mo, W) yielding the chelate complexes M(CO)₄(Me)₂XGeMe₂CH₂X′Me₂). compounds of low thermal stability are formed with the ligands (Me₂NGeMe₂CH₂X′Me₂ because of the weak donor ability of the GeNMe₂ group and with Me₂AsGeMe₂CH₂NMe₂ caused by strong steric ring tension. The new compounds are characterized by analytical and spectroscopic (n.m.r., i.r., m.s.) investigations.     

Darstellung und spektroskopische Untersuchungen von M(CO)4L2- und M(CO)3L3-Komplexen (M = Cr,Mo, W; L = Me3SiOCH2PMe2, Me2(CH2CH) SiOCH2PMe2)

Preparation and spectroscopical Investigations of M(CO)₄L₂ and M(CO)₃L₃ Complexes (M = Cr, Mo, W; L = Me₃SiOCH₂PMe₂, Me₂(CH₂?CH)SiOCH₂PMe₂ The coordinating properties of the ligands L¹ (?Me₃SiOCH₂PMe₂) and L² (?Me₂ViSiOCH₂PMe₂)¹) have been studied by synthesis and spectroscopic investigations (IR, NMR, MS) of their complexes M(CO)₄L₂ and M(CO)₃L₃(M = Cr, Mo, W). The complexes are obtained by replacement of norbornadiene (NBD) in M(CO)₄NBD or cycloheptatriene CHT in M(CO)₃CHT. Spectroscopic data (v(CO), δ δ) support the σ-donor/-π-acceptor model of the MP bonds.     

Alternativ-Liganden. XXX [1] Neue Tripod-Liganden XM' (OCH2PMe2)n(CH2CH2PMe2)3−n (M' = Si; Ge; n = 0–3) für Käfigstrukturen

Alternative Ligands. XXX Novel Tripod Ligands XM' (OCH₂PMe₂)_n(CH₂CH₂PMe₂)_3?n (M' = Si, Ge; n = 0–3) for Cage Structures Attempts to prepare new tripod ligands XSi(OCH₂PMe₂)₃ [X = CF₃ ( 15 ), C₆F₅ ( 16 ), NMe₂ ( 17 ), Cl ( 18 ), F ( 19 ), H ( 20 ), OEt ( 21 ), OMe ( 22 )] prove to be unsuccessful in spite of using different pathways, because the groups X undergo following reactions giving insoluble solids (polyadducts) or form inseparable mixtures, e. g. (RO)_nSi(OCH₂PMe₂)_4?n (R = Me, Et). In many cases Si(OCH₂PMe₂)₄ ( 13 ) can be isolated from the reaction mixture. The syntheses of the ligands XSi(CH₂CH₂PMe₂)₃ [X = NMe₂ ( 6 ), Cl ( 7 ), F ( 8 ), OMe ( 9 ), Vi ( 12 )], Si(OCH₂PMe₂)₄ ( 13 ) und Me₃GeOCH₂PMe₂ ( 14 ) are successful. The compounds MeSi(OCH₂PMe₂)₂CH₂CH₂NMe₂ ( 10 ) and MeSi(OCH₂PMe₂)₂CH₂CH₂P(CF₃)₂ ( 11 ) with different donor groups are obtained in good yields. The preparative program includes the synthesis of the known representatives MeSi(OCH₂PMe₃)₃ ( 1 ), MeSi(OCH₂PMe₂)₂CH₂CH₂PMe₂ ( 2 ), MeSi(OCH₂PMe₂)(CH₂CH₂PMe₂)₂ ( 3 ), MeSi(CH₂CH₂PMe₂)₃ ( 4 ) and MeGe(OCH₂PMe₂)₃ ( 5 ). Important preparative steps are the substitution of M'Cl (M' = Si, Ge) by Me₂PCH₂O groups and the photochemically induced or base catalyzed addition of HNMe₂, HPMe₂ or HP(CF₃)₂ to SiVi functions. The novel compounds are characterized by analytical and spectroscopic (IR, NMR, MS) investigations.     

Phosphanimin- und Phosphaniminato-Komplexe von Magnesium. Die Kristallstrukturen von [MgBr1,25I0,75(Me3SiNPMe3)(OEt2)], [MgI2(Me3SiNPMe3)2], [Mg2I2(Me3SiNPMe2CH2)Me3SiNPMe2CH2CH(Me)O)(OEt2)] und [MgBr(NPMe3)]4·C7H8

Phosphaneimine and Phosphoraneiminato Complexes of Magnesium. The Crystal Structures of [MgBr_1,25I_0,75(Me₃SiNPMe₃)(OEt₂)], [MgI₂(Me₃SiNPMe₃)₂], [Mg₂I₂(Me₃SiNPMe₂CH₂)(Me₃SiNPMe₂CH₂CH(Me)O)(OEt₂)], and [MgBr(NPMe₃)]₄ · C₇H₈ By reactions of the silylated phosphaneimine Me₃SiNPMe₃ with the Grignard reagents EtMgBr and MeMgI, respectively, the carbanionic phosphoraneiminato derivatives [XMg(CH₂PMe₂NSiMe₃)]_n (X ? Br, I) can be isolated as main products. The by-products of these reactions, [MgBr_1.25I_0.75(Me₃SiNPMe₃)(OEt₂)], [MgI₂(Me₃SiNPMe₃)₂] and [Mg₂I₂(CH₂PMe₂NSiMe₃)(O(Me)CHCH₂PMe₂NSiMe₃)(OEt₂)] were identified by crystal structure determinations. The phosphoraneiminato complex [MgBr(NPMe₃)]₄ · C₇H₈ with hetero cubane structure is formed by a metathesis reaction of [ZnBr(NPMe₃)]₄ with RMgBr (R ? Ph. Mes).     

Atran-analoge Verbindungen III. Atran-analoge Verbindungen des Typs Me2DCH2CH2OSi(Me) (OCH2CH2)2D′ Me (I) und Me2DCH2CH2OSi(Me) (OCH2CH2D′Me2)OCH2CH2D″ Me2 (II) (MeCH3; D,D′, D‴N,P, As)

Atrane-analogous Compounds. III. Atrane-analogous Compounds of the Type Me₂DCH₂CH₂OSi(Me)(OCH₂ CH₂)₂ D′Me (I) and Type Me₂DCH₂CH₂OSi(Me) OCH₂CH₂₂D″Me₂ (II) (Me?CH₃; D, D′, D″?N, P, As) Atrane analogous compounds I and II (Abb. 1) have been prepared by condensation reactions of trifunctional silanes RSiX₃ (X?Cl, OEt, NMe₂) with N-methyldiethanolamine, ß-chloroethanol, ß-dimethylaminoethanol, and ß-dimethylarsanoethanol according to eqn. (1) to (3) and reaction schemes of Figs. 2 and 3, respectively. For compounds of type I weak N→Si adduct bonding is indicated for the MeN-donor of the eight-membered ring by significant shifts of the MeNCH₂ and OCH₂ proton n.m.r. signals. For compounds of type II there is no n.m.r. evidence for D→Si interactions. In spite of equal Lewis acidity of the Si atoms differences in adduct formation are observed for cage, ring, and acyclic podand systems, which can be explained mainly by entropy effects connected to the formation of five-membered rings.     

Alternativ-Liganden. XXII. Rhodium(I)-Komplexe mit Donor/Akzeptor-Liganden des Typs Me2PCH2CH2SiXnMe3−(X = F,Cl, OMe)

Alternative Ligands. XXII. Rhodium(I) complexes with Donor/Acceptor Ligands of the Typs Me₂PCH₂CH₂SiX_nMe_3?n(X = F, Cl, OMe) Donor/acceptor ligand of the type Me₂PCH₂SiX_nMe_3?n react with [Rh(CO)₂Cl]₂ ( 1 ) to give the mononuclear complexes RhCl(CO)(PMe₂CH₂CH₂SiX_nMe_3?n)₂ ( 2-6 , Table 1) with planar geometry of the donor atoms, one exception being Me₂PCH₂CH₂CH₂SiCl₃, yielding the crystalline Rh^III-complex RhCl₂(CO)(PMe₂CH₂CH₂SiCl₂)(PMe₂CH₂CH₂SiCl₃) ( 7 ) by oxidative addition of one of the SiCl bonds to the Rh¹ precursor. Structures with Rh → Si interaction between the basic central atoms and the acceptor group SiX_nMe_3?n could be detected in the isolated products neither spectroscopically nor by X-ray diffraction of the two representatives RhCl(CO)(PMe₂CH₂CH₂SiF₃)₂ ( 2 ) and RhCl(CO)[PMe₂CH₂CH₂siF₃]₂ ( 2 ) and RhCl(CO) [PMe₂CH₂CH₂Si(OMe₃]₂ ( 6 ). The presence of such acid/base adducts in the reaction mixture is indicated for the more acidic acceptor groups SiX_nMe_3?n byv_co values near 1990cm^?1, (see Table 3). The complex RhCl(CO)PMe₃)(PMe₂CH₂CH₂SiF₃ ( 8 ) is obtained by the reaction of RhCl(CO)(PMe₃)₂ ( 9 ) with Me₂PCH₂SiF₃ and has been identified spectroscopically in a mixture with 2 and 9 .     

Lithiierte Phosphanimin‐Komplexe. Die Kristallstrukturen von [LiCH(Me)PEt2NSiMe3]4 und des Cuprats [Li{Me3SiNPMe2CH2–Cu–CH(SiMe2OLi)PMe2NSiMe3}]2

Lithiated Phosphoraneimine Complexes. Crystal Structures of [LiCH(Me)PEt₂NSiMe₃]₄ and of Cuprate [Li{Me₃SiNPMe₂CH₂–Cu–CH(SiMe₂OLi)PMe₂NSiMe₃}]₂ [LiCH(Me)PEt₂NSiMe₃]₄ ( 1 ) has been obtained as colorless, oxygen and moisture sensitive crystals from the reaction of the silylated phosphoraneimine Me₃SiNPEt₃ with ⁿbutyllithium in ⁿhexane at 0 °C. 1 crystallizes in the tetragonal space group I4₁/acd with eight formula units per unit cell. Lattice dimensions at –80 °C: a = b = 1505.2(1), c = 4747.4(6) pm, R₁ = 0.0278. 1 forms a Li₄ tetrahedron, the faces of which are capped with the carbon atoms of the carbanionic ‐CH(Me)‐ groups. The nitrogen atoms occupy the corners of the Li₄ tetrahedron by means of “inner solvation”. The cuprate [Li{Me₃SiNPMe₂CH₂–Cu–CH(SiMe₂OLi)PMe₂NSiMe₃}]₂ ( 4 ) has been obtained from the known [LiCH₂PMe₂NSiMe₃]₄ and copper(I) iodide in the presence of silicon grease (‐OSiMe₂‐)_n in diethylether, forming colorless oxygen and moisture sensitive crystals. 4 crystallizes in the triclinic space group P 1 with one formula unit per unit cell. Lattice dimensions at –50 °C: a = 1025.4(2), b = 1145.5(2), c = 1261.0(2) pm, α = 65.19(1)°, β = 79.55(1)°, γ = 77.94(1)°, R₁ = 0.039. 4 forms a centrosymmetric dimeric molecule with a central Li₂O₂ four‐membered ring, the oxygen atoms of which are connected by ‐SiMe₂‐ bridges with the cuprate fragment > CH–Cu–CH₂‐.     

Zur Chemie des Titan(III)-Komplexes [{(Me3Si)2N}2TiCH2SiMe2NSiMe3]–. Insertions-Reaktionen in die Ti–C-Bindung und Redox-Reaktionen

On the Chemistry of the Titanium(III) Complex [{(Me₃Si)₂N}₂TiCH₂SiMe₂NSiMe₃]^–. Insertion Reactions into the Ti–C Bond and Redox Reactions [Na(12-crown-4)₂][{(Me₃Si)₂N}₂TiCH₂SiMe₂NSiMe₃] ( 1 ) reacts with CO and the isonitrile CNCy (Cy = Cyclohexyl) under insertion into the Ti–C bond. After rearrangement planar five-membered titana(III)-heterocycles TiOCSiN and TiNCSiN with exocyclic C=CH₂ groups are formed. On the other hand, the insertion of CNBu^t leads to the primary insertion product [Na(12-crown-4)₂][{(Me₃Si)₂N}₂TiC(NBu^t)CCH₂SiMe₂NSiMe₃] ( 4 ) forming a new Ti(III)–C-bond. With NOBF₄ the anion of 1 can be oxydized to form the molecular complex [{(Me₃Si)₂N}₂TiCH₂SiMe₂NSiMe₃] ( 5 ), while with phenylacetylene redox disproportionation occurs, in the course of which the mixed ligand complex [Na(12-crown-4)₂][{(Me₃Si)₂N}₂Ti(NSiMe₃)(CH₂SiMe₂C≡C–Ph)] ( 6 ) can be isolated. 6 and the insertion products [Na(12-crown-4)₂][{(Me₃Si)₂N}₂TiOC(CH₂)SiMe₂NSiMe₃] ( 2 ) and [Na(12-crown-4)₂][{(Me₃Si)₂N}₂TiNCyC(CH₂)SiMe₂NSiMe₃] ( 3 ) are characterized by crystal structure determinations.     

Zur reaktion von metall-koordiniertem kohlenmonoxid mit yliden: XVI. Reversibler einbau von kohlenmonoxid in eine trimethylphosphonio (trimethylsiloxy) vinyl-einheit; Darstellung des zwitteriqnischen vinyl-chromkomplexes Cp(CO)(NO) CrC(OSiMe3)CHPMe3 und solvolytischer abbau sowie spaltung mit Me3P=CH2 oder MeX (X = I,SO3F)

The β-trimethylphosphonio(α-trimethylsiloxy)vinylchromium complex Cp(CO)(NO)$\text{C}$rC(OSiMe₃)=CHPMe₃ (2) can be isolated from a concentrated solution of Cp(CO)₂(NO)Cr (1) and Me₃P=CHSiMe₃ in benzene. 2 is obtained in better yield via O-silylation of the tetramethylphosphonium chromium acylate Me₄P[Cp(CO)(NO)CrC(O)CH=PMe₃] (3) with Me₃SiOSO₂CF₃. 2 decomposes readily by treatment with benzene to 1 and Me₃P=CHSiMe₃, which forms the ylide complex Cp(CO)(NO)CrCH(SiMe₃)PMe₃ (4) on photolysis. Degradation of 2 can be accelerated extraordinarily by traces of Me₃P=CH₂. With Me₃P= CH₂ (2 mol) controlled conversion of 2 to 3 and Me3P=CHSiMe₃ occurs. MeX (X = I, SO₃F) cleaves 2 to 1 and the phosphonium salt [Me₃PCH(SiMe₃)]X (5a,5b).     

Die Reaktion des [(Me3Si)2CH]2Al?CH2?Al [CH(SiMe3)2]2 mit LiCH(PMe2)2; Bildung eines fünfgliedrigen Al2C2P-Heterozyklus

The Reaction of [(Me₃Si)₂CH]₂Al? CH₂? Al [CH(SiMe₃)₂]₂ with LiCH(PMe₂)₂; Formation of a Five-membered Al₂C₂P Heterocycle The recently synthesized methylene bridged dialuminium compound [(Me₃Si)₂CH]₂Al? CH₂? Al [CH(SiMe₃)₂]₂ 3 reacts with one equivalent of LiCH(PMe₂)₂ in the presence of TMEDA to give an adduct with one aluminium atom coordinated by the carbanionic carbon atom and the second one coordinated by one phosphorus atom. A five-membered heterocycle 5 is formed, which was characterized by a crystal structure determination showing a strongly bent ring with the phosphorus atom located above the plane of the four remaining atoms (Al₂C₂). 5 is unstable in ethereal solution decomposing under ether cleavage to the educt 3 and the diphosphinomethane derivative CH₂(PMe₂)₂.     

Alternativ-Liganden VII: Chelatkomplexe des typs (Me = CH3; X = CH3, Cl)

Chelate complexes of the type (CO)₄M iX₂ (X = Me, Cl) have been prepared from Na[Mn(CO)₅] and HMn (CO)₅, respectively, by two-step reactions with the ligands Me₂PCH₂CH₂SiX₂R′ using alkali salt, amine or HCl elimination. (CO)₄M iCl₂ is also obtained by cleavage of Mn₂(CO)₁₀ with Me₂PCH₂CH₂SiCl₃. IN the case of HMn (CO)₅ the intermediates (CO)₄Mn (H) L [L = Me₂PSiMe₃, Me₂PCH₂CH₂SiMe₂ (NMe₂), Me₂PCH₂CH₂SiCl₂ (NMe₂] can be isolated. The new compounds were identified by analytical and spectroscopic (IR, PMR, MS) methods.     

CH Bond Activation during and after the Reactions of a Metallacyclic Amide with Silanes: Formation of a μ‐Alkylidene Hydride Complex,Its H–D Exchange,and β‐H Abstraction by a Hydride Ligand

Metallacyclic complex [(Me₂N)₃Ta(η²‐CH₂SiMe₂NSiMe₃)] ( 3 ) undergoes C?H activation in its reaction with H₃SiPh to afford a Ta/μ‐alkylidene/hydride complex, [(Me₂N)₂{(Me₃Si)₂N}Ta(μ‐H)₂(μ‐C‐η²‐CHSiMe₂NSiMe₃)Ta(NMe₂)₂] ( 4 ). Deuterium‐labeling studies with [D₃]SiPh show H–D exchange between the Ta?D ?Ta unit and all methyl groups in [(Me₂N)₂{(Me₃Si)₂N}Ta(μ‐D)₂(μ‐C‐η²‐CHSiMe₂NSiMe₃)Ta(NMe₂)₂] ([D₂]‐ 4 ) to give the partially deuterated complex [D_n]‐ 4 . In addition, 4 undergoes β‐H abstraction between a hydride and an NMe₂ ligand and forms a new complex [(Me₂N){(Me₃Si)₂N}Ta(μ‐H)(μ‐N‐η²‐C,N‐CH₂NMe)(μ‐C‐η²‐C,N‐CHSiMe₂NSiMe₃)Ta(NMe₂)₂] ( 5 ) with a cyclometalated, η²‐imine ligand. These results indicate that there are two simultaneous processes in [D_n]‐ 4 : 1) H–D exchange through σ‐bond metathesis, and 2) H?D elimination through β‐H abstraction (to give [D_n]‐ 5 ). Both 4 and 5 have been characterized by single‐crystal X‐ray diffraction studies.     

Bildung siliciumorganischer Verbindungen. 105. Reaktionen des (Cl3Si)2CPMe2Cl mit Silylphosphanen

Formation of Organosilicon Compounds. 105. Reactions of (Cl₃Si)₂C?PMe₂Cl with Silylphosphanes The reaction of (Cl₃Si)₂C?PMe₂Cl 1 with MeP(SiMe₃)₂ proceeds at 130°C (15 hrs.), by cleavage of all Si? P bonds to compounds 2, 3, 4, 5 . The course of this reaction incorporates a number of stages of which the compounds (Cl₃Si)₂C? PMe₂? P(Me)SiMe₃, (Cl₃Si)₂C?PMe₂? PMe? P(Me)SiMe₃ and ClP(Me)SiMe₃ are important and are yet to be isolated. The reaction of (Cl₃Si)₂C?PMe₂Cl with LiP(SiMe₂)₂ produces compound 2 as well as p₂(SiMe₃)₄ and P(SiMe₃)₃. The formation of 2 can be explained by the initial formation of the intermediate (Cl₃Si)₂C?PMe₂? P(SiMe₂)₂ with reacts with 1 to produce 2 and (ClP(SiMe)₃)₂. The formation of P₂(SiMe₃)₄ is also explained by the reaction of ClP(SiMe₃)₂ with LiP(SiMe₃)₄. The reaction of (Cl₃Si)₂C?PMe₂C(H)PMe₂ at 130°C/15–20 hrs. is related to the formation of (Me₃Si)₂C(H)Pme₂ from corresponding Si-methylated phosphorylides with the exception that, at 0°C, this reaction goes to completion within a few minutes.     

Alternativ-Liganden. XXI. Neue Donor/Akzeptor-Liganden Me2PCH2CH2SiFnMe3-n,Me2PCH2CH2SiR(C6H4F)2 und (2-Me2PC6H4)SiXMe2

Alternative Ligands. XXI. Novel Donor/Acceptor Ligands Me₂PCH₂CH₂SiF_nMe_3-n, Me₂PCH₂CH₂SiR(C₆H₄F)₂, and (2-Me₂PC₆H₄)SiXMe₂ Donor/acceptor ligands of the type Me₂PCH₂CH₂SiX₃ [X = Cl ( 1 ), F ( 2 ), Me ( 3 ), OMe ( 4 )], (Me₂PCH₂CH₂)₂SiX₂ [X = Cl ( 6 ), F ( 7 )], Me₂PCH₂CH₂SiX(C₆H₄F)₂ [X = F ( 5 ), Me ( 8 )], and Me₂PCH₂CH₂SiX_nMe_3-n[n = 1; X = Cl ( 10 ), F ( 11 ); n = 2; X = F ( 9 )] are prepared in yields between 42 and 95% by photochemical addition of Me₂PH to the corresponding vinylsilane precursors. In case of the halogen containing representatives formation of solid polyadducts, due to Lewis acid/base interaction between P-donor and Si-acceptor function, reduces the yields. Ligands of the type (2-Me₂PC₆H₄)SiXMe₂ [X = NMe₂ ( 12 ), Cl ( 13 ), F ( 14 )] are obtained by two different routes (Abb. 3), using 2-chlorobromobenzene as the starting material. New compounds have been characterized by analytical (C, H) and spectroscopic (NMR, MS) investigations. In order to elucidate the associative properties compounds 2 and 9 were used for the following experiments:

• – Study of the influence of dissolution on the proton and fluorine resonances of 2 and 9 ,
• – investigation of the adduct equilibrium (–H₂CF₃Si←PMe₂CH₂–)n + nBF₃ → n[F₃B←PMe₂CH₂CH₂SiF₃],
• – cleavage of the polyadduct of 2 using [NH₄]F and [Me₄N]F, respectively, for the formation of hexacoordinate complex anions [Me₂PCH₂CH₂SiF₅]^2?.

The results obtained confirm the assumption that oligo- and polymerisation are due to P→Si interaction.     

Synthese und Kristallstrukturen der silylierten Tris-Phosphanimine R?C(CH2PPh2NSiMe3)3 mit R  H und CH3

Synthesis and Crystal Structures of the Silylated λ⁵-Phosphazenes R? C(CH₂PPh₂NSiMe₃)₃ with R = H and CH₃ The title compounds are obtained by Staudinger reaction from the corresponding tripodal phosphanes R? C(CH₂PPh₂)₃ and trimethylsilylazide. Both complexes are characterized by their IR and NMR spectra and by crystal structure analyses. H? C(CH₂PPh₂NSiMe₃)₃ ( 1 ): Space group P2₁/c, Z = 4, structure determination with 7833 independent reflections, R = 0.055. Lattice dimensions at ?50°C: a = 1399.5, b = 2311.4, c = 1678.9 pm, β = 112.92°. CH₃? C(CH₂PPh₂NSiMe₃)₃ ( 2 ): Space group P1 , Z = 2, structure determination with 9251 independent reflections, R = 0.057. Lattice dimensions at ?50°C: a = 1276.5, b = 1386.9, c = 1790.2 pm; α = 85.55°, β = 69.39°, γ = 62.99°. 1 and 2 form monomeric molecules which are distinguished by their conformation.     

Alternativ-Liganden. XXXI. Nickelcarbonylkomplexe mit Tripod-Liganden des Typs XM′(OCH2PMe2)n(CH2CH2PR2)3–n (M′ = Si,Ge; n = 0–3)

Alternative Ligands. XXXI. Nickelcarbonyl Complexes of Tripod Ligands of the Type XM′(OCH₂PMe₂)_n(CH₂CH₂PR₂)_3–n (M′ = Si, Ge; n = 0–3) The coordinating properties of the tripod ligands RM′(OCH₂PMe₂)_n(CH₂CH₂PMe₂)_3–n (M′ = Si, Ge) ( 1–7 ), MeSi(OCH₂PMe₂)₂CH₂CH₂P(CF₃)₂ ( 8 ), MeSi(OCH₂PMe₂)₂CH₂CH₂NMe₂( 10 ) as well as of the tetradentate representative Si(OCH₂PMe₂)₄ ( 9 ) have been investigated by the preparation of the novel nickel carbonyl complexes LNiCO ( 11–18 ), Si(OCH₂PMe₂)₄[Ni(CO)₂]₂ ( 19 ) and (HOCH₂PMe₂)₂Ni(CO)₂ ( 20 ). They are obtained in moderate to good yields by the reaction of Ni(CO)₄ with the corresponding ligands in toluene (20–111°C) (see Table 1). The new compounds have been characterized by analytical (C, H) and spectroscopic investigations (IR; ¹H-, ¹³C-, ¹⁹F, ³¹P-NMR, MS). The ligand properties are discussed on the basis of spectroscopic data [in particular coordination shifts Δδ = δ(complex)—δ(ligand)] leading to the conclusion that the high electron density on Ni gives rise to a weak, but significant Ni→Si interaction. An important indication comes from the large low field shift Δδ_F = 34.5 ppm for the SiF acceptor bridge in 17 . This result is supported by an X-ray diffraction study of 11 giving an NiSi distance of 3.941(2) Å. With the exception of O2…?P3 (Abb. 7) all other O…?P through-cage contacts are longer than the NiSi distance. An additional release from the high charge density on Ni is obtained via π-backbonding to the neighbouring groups OCPMe₂, CCPMe₂ and CO.     

Synthesen zweizähniger P‐Donor/Sn‐Akzeptor‐Liganden: Koordinationsstudien mit Cp*Rh(CO)2 und CpRh(C2H4)2

Alternative Ligands. XXXV. Syntheses of Bidentate P‐Donor/Sn‐Acceptor Ligands: Coordination Experiments with Cp*Rh(CO)₂ and CpRh(C₂H₄)₂ Donor/acceptor ligands Me₂Sn(CH₂CH₂PMe₂)₂ ( 1 ) and Me₂Sn(OCH₂PMe₂)₂ ( 2 ) have been prepared by radical reaction of Me₂PVi with Me₂SnH₂ and by substitution of chlorine in Me₂SnCl₂ or of ethoxy groups in Me₂Sn(OEt)₂ by MOCH₂PMe₂ (M = Li, Na) and HOCH₂PMe₂, respectively. 2 cannot be isolated in pure form from the product mixture because, due to condensation reactions, the “ladder structure” [Me₂Sn(OCH₂PMe₂)₂OSnMe₂]₂ ( 3 ) is formed. The molecular structure of 3 was determined by X‐ray diffraction studies of single crystals. Attempts to produce the thiophosphoryl derivative of 3 result in the degradation of the ladder structure giving the thermally labile phosphane sulfide Me₂Sn(OCH₂P(S)Me₂)₂. Ligands 1 and 2 besides Me₂PCH₂CH₂SnMe₃ ( 4 ) have been used for the preparation of rhodium(I) complexes from Cp*Rh(CO)₂ ( 5 ) or CpRh(C₂H₄)₂ ( 10 ) as educts. The thermal reaction of 5 with 4 yields Cp*Rh(CO)PMe₂CH₂CH₂SnMe₃ ( 6 ), that of 5 with 1 a mixture of the mononuclear derivative Cp*Rh(CO) · PMe₂CH₂CH₂SnMe₂CH₂CH₂PMe₂ ( 7 ) and the binuclear complex [Cp*Rh(CO)PMe₂CH₂CH₂]₂SnMe₂ ( 8 ). The related system [Cp*Rh(CO)PMe₂CH₂O]₂SnMe₂ produced by reaction of 5 with 2 can only be detected in solution but, because of some side‐products, was not fully characterized. From 10 and 4 a mixture of mono‐ and disubstituted products, CpRh(C₂H₄)PMe₂CH₂CH₂SnMe₃ ( 11 ) and CpRh(PMe₂CH₂CH₂SnMe₃)₂ ( 12 ), is obtained. Reaction of 1 with 10 yields a mixture of the complexes CpRh(C₂H₄)PMe₂CH₂CH₂SnMe₂CH₂CH₂PMe₂ ( 13 ) and CpRh(Me₂CH₂CH₂)₂SnMe₂ ( 14 ). Some of the NMR data (¹³C, δδ_Sn) of 14 can be interpreted in terms of the expected Rh → Sn interaction. A definite proof by X‐ray diffraction on single crystals, so far, was not possible.