Synthese,Kristallstrukturen und quantenchemische Untersuchung von Verbindungen mit leiterartigem Al4P4‐ und hexagonal prismatischem Al6P6‐Grundgerüst

The reaction of AlCl₃ with Li₂PR (R = SiiPr₃, SiMeiPr₂) in a mixture of heptane and ether yields in the polycyclic compounds [(AlCl)₄(μ₃‐PR)₂(μ‐PR)₂(Et₂O)₂]( 1a : R = SiiPr₃; 1b : SiMeiPr₂) with a ladder‐shaped Al₄P₄ core. The coordination sphere of the outer aluminium atoms in these compounds is completed by ether ligands. In contrast, the reaction of AlCl₃ with Li₂PSiiPr₃ in pure heptane yields in the formation of the hexagonal prismatic compound [(AlCl)₆(μ₃‐PSiiPr₃)₆]( 2 ). 1 and 2 were characterized by single crystal X‐ray diffraction analysis as well as by ³¹P{1H} and ²⁷Al NMR spectroscopy. The structure determining effect of the solvent can be rationalized by quantumchemical calculations, which also show that the hexagonal prismatic structure is the most stable of the investigated oligomers in absence of ether.     

Untersuchungen zu Reaktionen des Diphosphanylsilans iPr2Si(PH2)2 mit Erdalkalimetallsilazaniden

The reaction of iPr₂Si(PH₂)₂ ( 1 ) with [Ca{N(SiMe₃)₂}₂(THF)₂] at 25 °C in molar ratio 1:1 yields the compound [Ca₃{iPr₂Si(PH)₂}₃(THF)₆] ( 2 ). Compound 2 consists of two Ca₂P₃ trigonal bipyramids with one conjoint calcium corner and SiiPr₂ bridged phosphorus atoms. In contrast, the same reaction at 60 °C yield the complex [Ca({P(SiiPr₂)₂PH}₂(THF)₄] ( 3 ). The isotype strontium compound [Sr({P(SiiPr₂)₂PH}₂(THF)₄] ( 4 ) was obtained from the reaction of iPr₂Si(PH₂)₂ with [Sr{N(SiMe₃)₂}₂(DME)₂]. The Compounds 2 – 4 were characterised by single crystal X‐ray diffraction, elemental analysis as well as IR and NMR spectroscopic techniques.     

Synthese von verbrückend substituierten sekundären Phosphanen sowie deren Reaktionen mit Triisopropylindium

In this work we report the synthesis and characterisation of the 1.5‐diphosphanyldiethylether O{C₂H₄PH(SiiPr₃)}₂ ( 2 ) in which two silyl‐substituted phosphine groups are linked by an ether bridge as well as the compound O(SiiPr₂PHEt)₂ ( 3 ) where two ethyl substitute phosphine groups are connected by a siloxane bridge. In addition, we describe the metalation of 2 and 3 with triisopropylindium. These reactions lead to the compounds [O{C₂H₄P(SiiPr₃)IniPr₂}₂] ( 4 ) and [O{SiiPr₂P(Et)IniPr₂}₂] ( 5 ) with In₂P₂ ring structures.     

Synthesis,Structure, and Stability of Lithium Arylphosphanidyl-diarylphosphane Oxide

The reaction of LiP(H)Tipp ( 2a ) and KP(H)Tipp ( 2b , Tipp = C₆H₂-2,4,6-iPr₃), which are accessible via metalation of Tipp-PH₂ ( 1 ), with bis(4-tert-butylphenyl)phosphinic chloride yields Tipp-P=P(OM)Ar₂ [M = Li ( 3a ) and K ( 3b )]. These complexes show characteristic chemical ³¹P shifts and large ¹J_PP coupling constants. These compounds degrade with elimination of the phosphinidene Tipp-P: and the alkali metal diarylphosphinites M–O–PAr₂ [M = Li ( 4a ) and K ( 4b )]. The phosphinidene forms secondary degradation products (like the meso and R,R/S,S-isomers of diphosphane Tipp-P(H)–P(H)Tipp ( 5 ) via insertion into a P–H bond of newly formed Tipp-PH₂), whereas the crystallization of [Tipp-P=P(OLi)Ar₂ · LiOPAr₂ · LiCl · 2Et₂O]₂ (i.e. [ 3a·4a· LiCl · 2Et₂O]₂) succeeds from diethyl ether. The metathesis reactions of LiP(SiiPr₃)Tipp and LiP(SiiPr₃)Mes (Mes = C₆H₂-2,4,6-Me₃) with Ar₂P(O)Cl yield Ar*-P=P(OSiiPr₃)Ar₂ (Ar* = Mes, Tipp) which degrade to Ar₂POSiiPr₃ and other secondary products.     

Vinyliden-Übergangsmetallkomplexe XXVI. Synthese und struktur kationischer Carbonyl-, Alken-, Vinyliden-, Alkinyl- und Alkin-Rhodiumkomplexe mit der Baueinheit trans-[Rh(PPr3)2]

The complex trans-[Rh(CO)(NH₃)(PiPr₃)₂]PF₆ (2) was prepared from [(η³-C₃H₅)Rh(PⁱPr₃)₂] (1), NH₄PF₆ and CO or from 1 and NH₄PF₆ in presence of an excess of methanol. With an excess of CO, the dicarbonyl and tricarbonyl compounds trans-[Rh(CO)₂(PⁱPr₃)₂]PF₆ (3) and [Rh(CO)₃(PⁱPr₃)₂]PF₆ (4) were obtained. Displacement of one CO ligand in 3 by pyridine and acetone led to the formation of trans-[Rh(CO)(py)PⁱPr₃)₂]PF₆ (5a) and trans-[Rh(CO) (O=CMe₂(PⁱPr₃)₂]PF₆ (6), respectively. Treatment of 1 with [pyH]BF₄ and pyridine gave trans-[Rh(py)₂(PⁱPr₃)₂]BF₄ (7); in presence of H₂ the dihydrido complex [RhH₂(py)₂(PⁱPr₃)₂]BF₄ (8) was formed. The reaction of 1 with NH₄PF₆ and ethylene produced trans [Rh(C₂H₄(NH₃(PⁱPr₃)₂]PF₆(9) whereas with methylvinylketone and acetophenone the octahedral hydridorhodium(III) complexes [RhH(η²-CH=CHC(=O)CH₃ (NH₃(PⁱPr₃)₂]PF₆(11) and [RhH(η2-C₆H₄C(=O)CH₃(NH₃(Pⁱpr₃)₂]PF₆ (13) were obtained. The synthesis of the cationic vinylidenerhodium(I) compounds trans-[Rh(=C=CHR)(py)(PⁱPr₃)₂]BF₄ (14–16) and trans-[Rh(=C=CHR)(NH₃)(PⁱPr₃) ₂]PF6 (17–19) was achieved either on treatment of 1 with [pyH]BF₄ or NH₄PF₆ in presence of 1-alkynes or by ethylene displacement from 9 by HCCR. With tert-butylacetylene as substrate, the alkinyl(hydrido)rhodium(III) complex [RhH(CC^tBu)(NH₃)(O=CMe₂)(PⁱPr₃) ₂]PF₆ (20) was isolated which in CH₂Cl₂ solution smoothly reacted to give 19 (R =^tBu). The cationic but-2-yne compound trans-[Rh(MeCCMe)(NH₃)(Pⁱ Pr₃)₂]PF₆ (21) was prepared from 1, NH₄PF₆ and C₂Me₂. The molecular structures of 3 and 14 were determined by X-ray crystallography; in both cases the square-planar coordination around the metal and the trans disposition of the phosphine ligands was confirmed.

Abstract

Der Komplex trans-[Rh(CO)(NH₃)(PⁱPr₃)₂]PF₆ (2) wurde aus [(η³-C₃H₅)Rh(PⁱPr₃)₂] (1), NH₄PF₆ und CO oder aus 1, NH₄PF₆ und Methanol hergestellt. In Gegenwart von überschüssigem CO wurden die Dicarbonyl- und Tricarbonyl-Verbindungen trans-[Rh(CO)₂(PⁱPr₃)₂]PF₆ (3) und [Rh(CO)₃(PⁱPr₃)₂]PF₆ (4) erhalten. Die Verdrängung eines CO-Liganden in 3 durch Pyridin oder Aceton führte zur Bildung von trans-[Rh(CO)(py)(PⁱPr₃)₂]PF₆ (5a) bzw. trans-[Rh(CO)(O=CMe₂)(PⁱPr₃)₂]PF₆ (6). Bei Einwirkung von [pyH]BF₄ und Pyridin auf 1 entstand trans-[Rh(py)₂(PⁱPr₃)₂]BF₄ (7); in Gegenwart von H₂ bildete sich der Dihydrido-Komplex [RhH₂(py)₂(PⁱPr₃) ₂]BF₄ (8). Die Reaktion von 1 mit NH₄PF₆ und Ethen lieferte trans-[Rh(C₂H₄)(NH₃)(PⁱPr₃)₂] PF₆ (9) während mit Methylvinylketon und Acetophenon die oktaedrischen Hydridorhodium(III)-Komplexe [RhH(η²-CH=CHC(=O)CH₃ (NH₃)-(PⁱPr₃)₂]PF₆ (11) und [RhH(η-²-C₆H₄C(=O)CH₃(NH₃)(PⁱPr₃)₂)₂]PF₆ (13) erhalten wurden. Die Synthese der kationischen Vinyli-denrhodium(I)-Verbindungen trans-[Rh(=C=CHR(py)(PⁱPr₃)₂]BF₄ (14–16) und trans-[Rh(=C=CHR)(NH₃)(PⁱPr₃)₂]PF₆ (17–19) gelang durch Einwirkung von [pyH]BF₄ bzw. NH₄PF₆ auf 1 in Gegenwart von 1-Alkinen oder durch Ethen-Verdrängung aus 9 mit HCCR. Mit tert-Butylacetylen als Reaktionspartner wurde der Alkinyl(hydrido)rhodium(III)-Komplex [RhH(CC^tBu)(NH₃(O=CMe₂)(PⁱPr₃)₂]PF₆ (20) isoliert, der in CH₂Cl₂-Lösung sofort zu 19 (R =^tBu) reagiert. Die kationische 2-Butin-Verbindung trans -[Rh(MeCCMe)(NH₃)PⁱPr₃)₂]PF₆ (21) wurde aus 1, NH₄PF₆ und C₂Me₂ hergestellt. Die Strukturen von 3 und 14 wurden kristallographisch bestimmt; in beiden Fa len ließ sich die quadratisch-planare Koordination des Metalls und die trans-Anordnung der Phosphanliganden bestätigen.     

Die Tris(triisopropylsilyl)pnikogene: Synthese und Charakterisierung von [E(SiiPr3)3] (E = P,As, Sb)

The Tris(triisopropylsilyl)pnikogenes: Synthesis and Characterisation of [E(Si ⁱ Pr₃)₃] (E = P, As, Sb) The compounds [E(SiⁱPr₃)₃] (E = P, As, Sb) ( 1 – 3 ) were prepared in high yields by the reaction of (Na/K)₃E with ⁱPr₃SiCl in DME. They were characterised by ¹H‐, ¹³C‐, ²⁹Si‐ and ³¹P‐NMR spectroscopy, mass spectrometry and single crystal X‐ray diffraction. Compound 1 , recently obtained in a different way, shows an unusual trigonal planar coordination of the central phosphorus atom. However, 2 and 3 , featuring increasing covalence radii of the central atoms, show an increasingly pyramidal structure. 1 – 3 crystallise isotyp in the cubic spacegroup Pa 3, the lattice constants are: 1 : a = 1860.1(2) pm, 2 : a = 1873.6(2) pm, 3 : a = 1897.1(2) pm.     

8‐Amidoquinoline, 8‐(Trialkylsilylamido)quinoline, 2‐Pyridylmethylamide,and (2‐Pyridylmethyl)(trialkylsilyl)amide Complexes of Gallium

Lithium 8‐amidoquinoline ( 1 ) and lithium 8‐(trialkylsilylamido)quinoline [SiMe₂tBu ( 2 ), SiiPr₃ ( 3 )] react with dimethylgallium chloride to the metathesis products dimethylgallium 8‐amidoquinoline ( 4 ) as well as dimethylgallium 8‐(trialkylsilylamido)quinoline [SiMe₂tBu ( 5 ), SiiPr₃ ( 6 )]. The gallium atoms are in distorted tetrahedral environments. During the synthesis of 5 , orange dimethylgallium 2‐butyl‐8‐(tert‐butyldimethylsilylamido)quinoline ( 7 ) was found as by‐product. The metathesis reactions of Me₂GaCl with LiN(R)CH₂Py (Py = 2‐pyridyl) yield the corresponding 2‐pyridylmethylamides Me₂Ga‐N(H)CH₂Py ( 8 ), Me₂Ga‐N(SiMe₂tBu)CH₂Py ( 9 ) and Me₂Ga‐N(SiiPr₃)CH₂Py ( 10 ). In these complexes the gallium atoms show a distorted tetrahedral coordination sphere. However, derivative 8 crystallizes dimeric with bridging amido units whereas in 9 and 10 the 2‐pyridylmethylamido moieties act as bidentate ligands leading to monomeric molecules.     

Molekulare Aggregate von donorsolvensfreien Lithiumsilylphosphaniden mit dem Triphenylsilyl- und Triisopropylsilyl-Substituenten am Phosphor

Molecular Aggregates of Donorsolvent-Free Lithiumsilylphosphanides with the Triphenylsilyl- and Triisopropylsilyl-Substituent at Phosphorus The lithiumphosphanides 6 and 7 were formed by lithiation of the bulky disilylphosphanes 1 a and 1 b with nBuLi in toluene as solvent. 1 a and 1 b are accessible in high yield by simple salt-elimination reactions, following a one-pot procedure. X-ray crystal structure determinations revealed that 6 exists as an donorsolvent-free dimer, whereas, surprisingly, 7 is a mixed tetrameric aggregate bearing three molecules LiP(SiiPr₃)₂ and one molecule LiPH(SiiPr₃). The aggregate building block LiPH(SiiPr₃) is obviously formed upon a nucleophilic Si? P bond cleavage in 1 b under the reaction conditions used for the lithiation. The tetramer 7 shows a unprecedented structure of a lithiumphosphanide: The lithium atoms are twofold-coordinated and exhibit extremely large endocyclic angles (153.4–164.5°). Furthermore the P₄Li₄ heterocyclooctane framework ist strongly flattened and the bulky silyl groups obviously suppress a rearrangement to a normal ladder-like structure. The flattened pyramidal coordination of the P atom, which bears one SiiPr₃ group and one H atom, is probably due to steric effects.     

Unexpected Coordination Modes of the Tris(imidazolyl)phosphane Oxide Ligand 4‐TIPOiPr in the Chloro Complexes of Zinc,Cobalt and Nickel

The coordination chemistry of the water soluble phosphane oxide ligand tris[2‐isopropylimidazol‐4(5)‐yl]phosphane oxide, 4‐TIPO^iPr, has been explored. A variety of 3d‐metal halide complexes have been prepared and the crystal structures of the solvates [(4‐TIPO^iPr)ZnCl₂]·MeOH·¹/₂dioxane ( 1 ·MeOH·¹/₂dioxane), [(4‐TIPO^iPr)CoCl₂]·H₂O·2dioxane ( 2 ·H₂O·2dioxane) and [(4‐TIPO^iPr)₂Ni(MeOH)₂]Cl₂·2MeOH ( 3 ·2MeOH) have been determined. All three structures show unprecedented coordination modes of the 4‐TIPO^iPr ligand. Both zinc and cobalt complexes are coordinated in a bidentate κ²N fashion, whereas the nickel atom is coordinated by two ligands in a κN,O mode using one imidazolyl substituent and the P=O oxygen atom.     

Synthese,Struktur und Thermolyse der ternären Ammoniumnitrate (NH4)3[M2(NO3)(9] (M  La?Gd)

Synthesis, Structure, and Thermolysis of the (NH₄)₃[M₂(NO₃)₉] (M ? La? Gd) The ternary ammonium nitrates (NH₄)₃[M₂(NO₃)₉] (M ? La-Gd) are obtained as single crystals from a solution of the respective sesquioxides in a melt of NH₄NO₃ and sublimation of the excess NH₄NO₃. In the crystal structure of (NH₄)₃[Pr₂(NO₃)₉] (cubic, P4₃32, Z = 4, a = 1 377.0(1) pm, R = 0.038, R_w = 0.023) Pr³⁺ is surrounded by six bidentate nitrate ligands of which three are bridging to neighbouring Pr³⁺ ions. This results in a branched folded chain, held together by the NH₄⁺ ions which occupy cavities in the structure. (NH₄)₃[Pr₂(NO₃)₉] is the first intermediate product of the thermal decomposition of (NH₄)₂[Pr(NO₃)₅(H₂O)₂] · 2H₂O.     

Tetraphosphanylsilane – A Mild PH2‐Transfer Reagent and Building Block for the Synthesis of a Rhombododecahedral Li6P6Si2‐Cluster Framework

Reaction of the PH₂‐transfer reagent Si(PH₂)₄ ( 1 ) with SiCl₄ affords a mixture of the Cl_nSi(PH₂)_4–n compounds ( 2 a , n = 1), ( 2 b , n = 2), and ( 2 c , n = 3) which were characterized by ¹H‐³¹P‐COSY NMR spectroscopy. The formation of ( 2 a ) is drastically accelerated by using GeCl₄ instead of SiCl₄ as PH₂ acceptor, but a stable molecular GeCl_4–n(PH₂)_n containing product could not be obtained. In contrast, conversion of (C₆F₅)₃GeCl with Si(PH₂)₄ ( 1 ) furnishes 2 a but also the remarkably stable tris(pentafluorophenyl)phosphaneylgermane ( 3 ). The latter is isolated in the form of colorless crystals in 97% yield and represents the first PH₂‐substituted germane being structurally characterized by single‐crystal X‐ray diffraction. Protolysis of 1 with MeOH and PhOH occurs relatively fast and leads to mixtures of compounds of the type (RO)_nSi(PH₂)_4–n ( 4 , n = 1), ( 5 , n = 2), and ( 6 , n = 3). The sterically congested phenols MesOH and 3,5‐Me₂PhOH react with 1 only to the respective mono‐ and disubstituted silylphosphanes ( 4 c , d ) and ( 5 c , d ), respectively; 4 c and 4 d were isolated by fractional condensation in the form of air‐ and moisture‐sensitive oils. Lithiation of 1 with four molar equiv. of LiNiPr₂ in THF/Et₂O at –80 °C, surprisingly, leads to insoluble Si(PHLi)₄ ( 8 a ) which was tetrasilylated with iPr₃SiOSO₂CF₃, affording the tetrakis(triisopropylsilylphosphaneyl)silane ( 8 b ). However, attempts to achieve the tetralithiation of the P atoms in 8 b through reaction with four molar equiv. BuLi leads to the unexpected cluster formation of butyl‐tris[lithium(triisopropylsilyl)phosphanideyl] silane‐dimer ( 9 ) in 30% yield and LiPHSiiPr₃; compound 9 consists of a Li₆P₆Si₂ cluster framework.     

Neue Kupferkomplexe mit Phosphaalkenliganden. Molekülstruktur von [Cu{P(Mes*)C(NMe2)2}2]BF4 (Mes* = 2,4,6‐tBu3C6H2)

New Copper Complexes Containing Phosphaalkene Ligands. Molecular Structure of [Cu{P(Mes*)C(NMe₂)₂}₂]BF₄ (Mes* = 2,4,6‐tBu₃C₆H₂) Reaction of equimolar amounts of the inversely polarized phosphaalkene tBuP=C(NMe₂)₂ ( 1a ) and copper(I) bromide or copper(I) iodide, respectively, affords complexes [Cu₃X₃{μ‐P(tBu)C(NMe₂)₂}₃] ( 2 ) (X =Br) and ( 3 ) (X = I) as the formal result of the cyclotrimerization of a 1:1‐adduct. Treatment of 1a with [Cu(L)Cl] (L = PiPr₃; SbiPr₃) leads to the formation of compounds [CuCl(L){P(tBu)C(NMe₂)₂}] ( 4a ) (L = PiPr₃) and ( 4b ) (L = SbiPr₃), respectively. Reaction of [(MeCN)₄Cu]BF₄ with two equivalents of PhP=C(NMe₂)₂ ( 1b ) yields complex [Cu{P(Ph)C(NMe₂)₂}₂]BF₄ ( 5b ). Similarly, compounds [Cu{P(Aryl)C(NMe₂)₂}₂]BF₄ ( 5c (Aryl = Mes and 5d (Aryl = Mes*)) are obtained from ArylP=C(NMe₂)₂ ( 1c : Aryl = Mes; 1d : Mes*) and [(MeCN)₄Cu]BF₄ in the presence of SbiPr₃. Complexes 2 , 3 , 4a , 4b , and 5b‐5d are characterized by means of elemental analyses and spectroscopy (¹H‐, ¹³C{¹H}‐, ³¹P{¹H}‐NMR). The molecular structure of 5d is determined by X‐ray diffraction analysis.     

[Ni(iPr2Im)2Br2]: A Convenient Entry into NHC Nickel ­Chemistry

The reaction of the NHC iPr₂Im [NHC=N‐heterocyclic carbene, iPr₂Im = 1, 3‐bis(isopropyl)imidazolin‐2‐ylidene] with freshly prepared NiBr₂ in thf or dme results in the formation of the air stable nickel(II) complex trans‐[Ni(iPr₂Im)₂Br₂] ( 2 ). Complex 2 was structurally characterized. Thermal analysis (DTA/TG) reveals a very high decomposition temperature of 298 °C. Reduction of 2 with sodium or C₈K in the presence of the olefins COD (cyclooctadiene) or COE (cyclooctene) affords the highly reactive compounds [Ni₂(iPr₂Im)₄(COD)] ( 1 ) and [Ni(iPr₂Im)₂(COE)] ( 4 ). Alkylation of 2 with organolithiums leads to the formation of trans‐[Ni(iPr₂Im)₂(R)₂] [R = Me ( 5 ), CH₂SiMe₃ ( 6 )], whereas the reaction of 2 with LiCp* [Cp* = (η⁵‐C₅(CH₃)₅)] at 80 °C causes the loss of one NHC ligand and affords [(η⁵‐C₅(CH₃)₅)Ni(iPr₂Im)Br] ( 7 ).     

Synthese und Deprotonierung des verzweigten Triphosphanyltetrasilans PhSi(SiMe2PH2)3

The branched triphosphanyltetrasilane PhSi(SiMe₂PH₂)₃ ( 1 ) could be obtained in a three‐stage synthesis. It was characterised by multi‐nuclear NMR spectroscopy, mass spectrometry and IR spectroscopy. Deprotonation of 1 with GaiPr₃ or [M{N(SiMe₃)₂}₂(thf)₂] (M = Ca, Sr, Ba) yields new phosphorus bridged polynuclear complexes of these metals with phosphorus atoms connected through tetrasilane fragments. While trinuclear complexes with single deprotonated phosphanyl groups could be obtained from the reactions of 1 with GaiPr₃, calcium or barium silazanide (compounds 2 , 3 and 5 ), the tetranuclear complex [Sr₄{PhSi(SiMe₂PH)₂(SiMe₂P)}₂(dme)₆] ( 4 ) was formed in the reaction of 1 with strontium silazanide. In this compound, two of six phosphorus atoms are deprotonated twice. Compounds 2 – 5 were characterised by single‐crystal X‐ray diffraction, elemental analysis as well as IR spectroscopy and as far as possible by NMR spectroscopic techniques.     

Der Dihydridoiridium(III)‐Komplex [IrH2Cl(PiPr3)2] als Molekülbaustein für unsymmetrische Rhodium–Iridiumund Iridium–Iridium‐Zweikernverbindungen

The Dihydridoiridium(III) Complex [IrH₂Cl(P i Pr₃)₂] as a Molecular Building Block for Unsymmetrical Binuclear Rhodium–Iridium and Iridium–Iridium Compounds The title compound [IrH₂Cl(PiPr₃)₂] ( 3 ) reacts with the chloro‐bridged dimers [RhCl(PiPr₃)₂]₂ ( 1 ) and [IrCl(C₈H₁₄)(PiPr₃)]₂ ( 5 ) by cleavage of the Cl‐bridges to give the unsymmetrical binuclear complexes 4 and 6 with Rh(μ‐Cl)₂Ir and Ir(μ‐Cl)₂Ir as the central building block. The reactions of 3 with the bis(cyclooctene) and (1,5‐cyclooctadiene) compounds [MCl(C₈H₁₄)₂]₂ ( 7 , 8 ) and [MCl(η⁴‐C₈H₁₂)]₂ ( 9 , 10 ) (M = Rh, Ir) occur analogously and afford the rhodium(I)‐iridium(III) and iridium(I)‐iridium(III) complexes 11 – 14 in 70–80% yield. Treatment of [(η⁴‐C₈H₁₂)M(μ‐Cl)₂IrH₂(PiPr₃)₂] ( 13 , 14 ) with phenylacetylene leads to the formation of the substitution products [(η⁴‐C₈H₁₂)M(μ‐Cl)₂IrH(C≡CPh)(PiPr₃)₂] ( 15 , 16 ) without changing the central molecular core. Similarly, the compound [(η⁴‐C₈H₁₂)Rh(μ‐Br)₂IrH(C≡CPh)(PiPr₃)₂] ( 18 ) has been prepared; it was characterized by X‐ray crystallography.     

Synthese,Kristallstruktur und Magnetismus von [(CH3)2NH2][PrCl4(H2O)2]

Preparation, Crystal Structure, and Magnetism of [(CH₃)₂NH₂][PrCl₄(H₂O)₂] The complex water containing chloride [(CH₃)₂NH₂][PrCl₄(H₂O)₂] has been prepared for the first time and the crystal structure has been determined from single crystal X‐ray diffraction data. The compound crystallizes orthorhombically in the space group Cmca (Z = 8) with a = 1796.6(2) pm, b = 940.7(1) pm, and c = 1238.4(2) pm. The anionic part of the structure is built up by chains of edge‐connected trigondodecahedra [PrCl₆(H₂O)₂]^3– according to [PrCl_4/2Cl₂(H₂O)₂]^–, which are held together by dimethylammonium cations ([(CH₃)₂NH₂]⁺). In order to study the interactions between the praseodymium cation (Pr³⁺) and the ligands magnetic measurements were carried out. The magnetic data were interpreted by ligand field calculations applying the angular overlap model.     

Metalated diphosphanylsiloxanes with polycyclic and polymeric structures

The reactions of the diphosphanylsiloxane O(SiiPr₂PH₂)₂ (1) with MiPr₃ (M = Ga, In) produced the polycyclic compounds [O{SiiPr₂(PH)MiPr₂}{SiiPr₂(P)MiPr}] ₂ (2, 3). Compounds 2 and 3 are composed of three M₂P₂ rings forming a ladder structure and two OSi₂P₂M rings. By reactions of 1 with n-BuLi the polymeric compound [O(SiiPr₂PHLi)₂(THF)(TMEDA)] · THF (4) was obtained.     

Reaction of RGeBr3 (R=iPr2C6H3NSiMe3) with Ammonia To Give (RGe)2(NH2)4(NH): A Compound Containing Terminal NH2 Groups

The surprisingly facile preparation of (RGe)₂(NH₂)₄(NH) ( 1 ; R=iPr₂C₆H₃NSiMe₃), which contains one NH and four NH₂ groups, is achieved by the introduction of gaseous ammonia into a solution of iPr₂C₆H₃NSiMe₃GeBr₃ in diethyl ether.     

Iridium(I)‐ und Iridium(III)‐Komplexe mit Triisopropylarsan als Ligand

Iridium(I) and Iridium(III) Complexes with Triisopropylarsane as Ligand The ethene complex trans‐[IrCl(C₂H₄)(AsiPr₃)₂] ( 2 ), which was prepared from [IrCl(C₂H₄)₂]₂ and AsiPr₃, reacted with CO and Ph₂CN₂ by displacement of ethene to yield the substitution products trans‐[IrCl(L)(AsiPr₃)₂] ( 3 : L = CO; 4 : L = N₂). UV irradiation of 2 in the presence of acetonitrile gave via intramolecular oxidative addition the hydrido(vinyl)iridium(III) compound [IrHCl(CH=CH₂)(CH₃CN)(AsiPr₃)₂] ( 5 ). The reaction of 2 with dihydrogen led under argon to the formation of the octahedral complex [IrH₂Cl(C₂H₄)(AsiPr₃)₂] ( 7 ), whereas from 2 under 1 bar H₂ the ethene‐free compound [IrH₂Cl(AsiPr₃)₂] ( 6 ) was generated. Complex 6 reacted with ethene to afford 7 and with pyridine to give [IrH₂Cl(py)(AsiPr₃)₂] ( 8 ). The mixed arsane(phosphane)iridium(I) compound [IrCl(C₂H₄)(PiPr₃)(AsiPr₃)] ( 11 ) was prepared either from the dinuclear complex [IrCl(C₂H₄)(PiPr₃)]2 ( 9 ) and AsiPr₃ or by ligand exchange from [IrCl(C₂H₄)(PiPr₃)(SbiPr₃)] ( 10 ) und triisopropylarsane. The molecular structure of 5 was determined by X‐ray crystallography.     

Theoretical Study of Pd11Si6 Nanosheet Compounds Including Seven‐Coordinated Si Species and Its Ge Analogues

Nanosheet compounds Pd₁₁(SiiPr)₂(SiiPr₂)₄(CNtBu)₁₀ ( 1 ) and Pd₁₁(SiiPr)₂(SiiPr₂)₄(CNMes)₁₀ ( 2 ), containing two Pd₇(SiiPr)(SiiPr₂)₂(CNR)₄ plates (R=tBu or Mes) connected with three common Pd atoms, were investigated with DFT method. All Pd atoms are somewhat positively charged and the electron density is accumulated between the Pd and Si atoms, indicating that a charge transfer (CT) occurs from the Pd to the Si atoms of the SiMe₂ and SiMe groups. Negative regions of the Laplacian of the electron density were found between the Pd and Si atoms. A model of a seven‐coordinated Si species, that is, Pd₅(Pd?SiMe), is predicted to be a stable pentagonal bipyramidal molecule. Five Pd atoms in the equatorial plane form bonding overlaps with two 3p orbitals of the Si atom. This is a new type of hypervalency. The Ge analogues have geometry and an electronic structure similar to those of the Si compounds. But their formation energies are smaller than those of the Si analogues. The use of the element Si is crucial to synthesize these nanoplate compounds.