TAS‐Indolid und TAS‐Carbazolid: Strukturen von [TAS]+[IndHInd]− und [TAS]+[Carb]−·½CarbH

TAS Indolide and TAS Carbazolide: Structures of [TAS]⁺[IndHInd]^? and [TAS]⁺[Carb]^?·½CarbH From the reaction of TAS‐fluoride [(Me₂N)₃S]⁺[Me₃SiF₂]^? with trimethylsilyl‐indole and trimethylsilyl‐carbazole TAS‐indolide and TAS‐carbazolide are formed. During crystallisation partially protonation to indole and carbazole occurs, resulting in the formation of [TAS]⁺[IndHInd]^? ( 3a ) and [TAS]⁺[Carb]^?·½CarbH ( 5a ) according to X‐ray analysis.     

Solvolysis Products of the Types [RhMeL2(Me3[9]aneN3)]2+ and [RuCl3—XLX(Me3[9]aneN3)](x)+ (x = 1‐2) and Preparation and Structure of [Ru([9]aneS3)(Me3[9]aneN3)](CF3SO3)2

Solvolysis of [RhMe(CF₃SO₃)₂(Me₃[9]aneN₃)] ( 1 ) (Me₃[9]aneN₃ = 1, 4, 7‐trimethyl‐1, 4, 7‐triazacyclononane) in CH₃CN, DMSO or pyrazole (L) leads to substitution of both trifluoromethylsulfonate ligands and formation of the cationic complexes [RhMeL₂(Me₃[9]aneN₃)](CF₃SO₃)₂ 3—5 . In contrast, treatment of [RuCl₃(Me₃[9]aneN₃)] ( 2 ) with Ag(CF₃SO₃) in a 1:3 ratio for 2h in CH₃CN leads to formation of the tetranuclear complex [{RuCl₃(Me₃[9]aneN₃)}₂Ag₂(CF₃SO₃)(CH₃CN)](CF₃SO₃) · CH₃CN ( 6 ) with a novel [(RuCl₃)₂Ag₂] core. More forcing conditions enable the substitution of respectively one or two chloride ligands by CH₃CN (reflux 18h) or DMF (85°C, 1h) to afford [RuCl₂(CH₃CN)(Me₃[9]aneN₃)](CF₃SO₃) ( 7 ) and [RuCl(DMF)₂(Me₃[9]aneN₃)](CF₃SO₃)₂ ( 8 ). The heteroleptic sandwich complex [Ru([9]aneS₃)(Me₃[9]aneN₃)](CF₃SO₃)₂ ( 9 ) can be prepared by reduction of 2 with Zn powder in acetone in the presence of 3 equiv. of Ag(CF₃SO₃), followed by addition of [9]aneS₃ (1, 4, 7‐trithiacyclononane). The redox potential E°(Ru³⁺/Ru²⁺) of +1.87 V vs NHE for 9 is only —0.12 V lower than that of the homoleptic complex [Ru([9]aneS₃)₂]²⁺. Crystal structures are reported for 3 — 9 .     

Preparation and Structure of [Me3N(CF3)2BCCB(CF3)2NMe3]

Bis‐trimethylamine‐ethynyl‐di‐bis(trifluoromethyl)borane [Me₃N(CF₃)₂BCCB(CF₃)₂NMe₃] ( 1 ) has been prepared from trimethylamine‐ethynyl‐bis(trifluoromethyl)borane, [HCCB(CF₃)₂NMe₃], and dimethylamino‐bis(trifluoromethyl)borane, (CF₃)₂BNMe₂. The structure of 1 has been determined by x‐ray crystallography. In the solid state the molecule possesses crystallographic C_i symmetry. The acetylenic attachment to the boron atom is characterized by a short B–C bond length of 1.565(4) Å and an essentially linear B–C–C′ bond angle of 178.1(4)°.     

Reaktionen von ClS[OCH(CF3)2]3 und S[OCH(CF3)2]2 mit Phosphor(III)-Verbindungen

Reactions of ClS[OCH(CF₃)₂]₃ and S[OCH(CF₃)₂]₂ with Phosphorus(III) Derivatives The sulfurane ClS[OCH(CF₃)₂]₃ reacts with Me₃P to give the phosphonium salt [Me₃POCH(CF₃)₂]⁺Cl^?, in the case of (MeO)₃P products of an Arbuzov reaction are found: (MeO)₂P-(:O)OCH(CF₃)₂ and MeCl; the sulfurane is reduced to the sulfoxylate S[OCH(CF₃)₂]₂. The cyclic phosphite FP[OC(CF₃)₂C(CF₃)₂O] and P[OCH(CF₃)₂]₃ furnish derivatives of pentacoordinated phosphorus upon reaction with ClS[OCH(CF₃)₂]₃. The sulfoxylate S[OCH(CF₃)₂]₂ oxidises Me₃P, (MeO)₃P and P[OCH(CF₃)₂]₃ to form R₃P? O and R₃P? S (R = Me, OMe, OCH(CF₃)₂). The ether (CF₃)₂CHOCH(CF₃)₂ is isolated, too.     

Synthese,Struktur und Reaktivität des Ferrioarsaalkens [(η5‐C5Me5)(CO)2FeAs=C(Ph)NMe2]

Synthesis, Structure, and Reactivity of the Ferrioarsaalkene [(η⁵‐C₅Me₅)(CO)₂FeAs=C(Ph)NMe₂] Reaction of equimolar amounts of the carbenium iodide [Me₂N(Ph)CSMe]I and LiAs(SiMe₃)₂ · 1.5 THF afforded the thermolabile arsaalkene Me₃SiAs = C(Ph)NMe₂ ( 1 ), which in situ was converted into the black crystalline ferrioarsaalkene [(η⁵‐C₅Me₅)(CO)₂FeAs=C(Ph)NMe₂)] ( 2 ) by treatment with [(η⁵‐C₅Me₅)(CO)₂FeCl]. Compound 2 was protonated by ethereal HBF₄ to yield [(η⁵‐C₅Me₅)(CO)₂FeAs(H)C(Ph)NMe₂]BF₄ ( 3 ) and methylated by CF₃SO₃Me to give [(η⁵‐C₅Me₅)(CO)₂FeAs(Me)C(Ph)NMe₂]‐ SO₃CF₃ ( 4 ). [(η⁵‐C₅Me₅)(CO)₂FeAs[M(CO)_n]C(Ph)NMe₂] ( 5 : [M(CO)_n] = [Fe(CO)₄]; 6 : [Cr(CO)₅]) were isolated from the reaction of 2 with [Fe₂(CO)₉] or [{(Z)‐cyclooctene}Cr(CO)₅], respectively. Compounds 2 – 6 were characterized by means of elemental analyses and spectroscopy (IR, ¹H, ¹³C{¹H}‐NMR). The molecular structure of 2 was determined by X‐ray diffraction analysis.     

Easy Access to the Copper(III) Anion [Cu(CF3)4]−

CuCl or pre‐generated CuCF₃ reacts with CF₃SiMe₃/KF in DMF in air to give [Cu(CF₃)₄]^? quantitatively. [PPN]⁺, [Me₄N]⁺, [Bu₄N]⁺, [PhCH₂NEt₃]⁺, and [Ph₄P]⁺ salts of [Cu(CF₃)₄]^? were prepared and isolated spectroscopically and analytically pure in 82–99 % yield. X‐ray structures of the [PPN]⁺, [Me₄N]⁺, [Bu₄N]⁺, and [Ph₄P]⁺ salts were determined. A new synthetic strategy with [Cu(CF₃)₄]^? was demonstrated, involving the removal of one CF₃^? from the Cu atom in the presence of an incoming ligand. A novel Cu^III complex [(bpy)Cu(CF₃)₃] was thus prepared and fully characterized, including by single‐crystal X‐ray diffraction. The bpy complex is highly fluxional in solution, the barrier to degenerate isomerization being only 2.3 kcal mol^?1. An NPA study reveals a huge difference in the charge on the Cu atom in [Cu(CR₃)₄]^? for R=F (+0.19) and R=H (+0.46), suggesting a higher electron density on Cu in the fluorinated complex.     

[2+4] and [2+2] Cycloaddition Reactions of N‐Sulfinyl Carboxylic Acid Amides with (CF3)2BNMe2. Crystal Structure of cyclo‐(CF3)2B‐NMe2‐S(=O)‐N=C(p‐CH3C6H4)‐O

N‐sulfinylacylamides R‐C(=O)‐N=S=O react with (CF₃)₂BNMe₂ ( 1 ) to form, by [2+4] cycloaddition, six‐membered rings cyclo‐(CF₃)₂B‐NMe₂‐S(=O)‐N=C(R)‐O for R = Me ( 2 ), t‐Bu ( 3 ), C₆H₅ ( 4 ), and p‐CH₃C₆H₄ ( 5 ) while N‐sulfinylcarbamic acid esters R‐O‐C(=O)‐N=S=O react with 1 to yield mixtures of six‐membered (cyclo‐(CF₃)₂B‐NMe₂‐S(=O)‐N=C(OR)‐O) and four‐membered rings (cyclo‐(CF₃)₂B‐NMe₂‐S(=O)‐N(C=O)OR) for R = Me ( 6 and 9 ), Et ( 7 and 10 ), and C₆H₅ ( 8 and 11 ). The structure of 5 has been determined by X‐ray diffraction.     

Umsetzung von C(NMe2)4 mit Ni(CO)4 – Synthesen und Strukturen von [C(NMe2)3][(CO)3NiC(O)NMe2], [C(NMe2)3]2[Ni5(CO)12] und [C(NMe2)3]3[Ni6(CO)12][O2CNMe2]

Reaction of C(NMe₂)₄ with Ni(CO)₄ – Syntheses and Structures of [C(NMe₂)₃][(CO)₃NiC(O)NMe₂], [C(NMe₂)₃]₂[Ni₅(CO)₁₂], and [C(NMe₂)₃]₃[Ni₆(CO)₁₂][O₂CNMe₂] The reaction of C(NMe₂)₄ with Ni(CO)₄ in THF produces the carbamoyl complex [C(NMe₂)₃][(CO)₃NiC(O)NMe₂] ( 1 ); side products are the purple cluster compound [C(NMe₂)₃]₂[Ni₅(CO)₁₂] · THF ( 2 · THF) and the red cocristallization product [C(NMe₂)₃]₃[Ni₆(CO)₁₂][O₂CNMe₂] ( 3 ). All compounds were studied by X‐ray diffraction analyses. The cations of 3 are all disordered but not those of 1 and 2 . The unit cell of 1 contains two crystallographically independent anions (I and II) which differ in the dihedral angle between the plane of the carbamoyl ligand and the plane defined by the atoms C_Carbamoyl–Ni–CO amounting 0° in the anion I and 18° in the anion II.     

Synthesen und NMR‐Untersuchungen von Salzen mit den neuen Anionen [PtXn(CF3)6‐n]2— (n = 0 ‐ 5, X = F,OH, Cl,CN) und die Kristallstrukturanalyse von K2[(CF3)2F2Pt(μ‐OH)2PtF2(CF3)2]·2H2O

Syntheses and NMR Spectroscopic Ivestigations of Salts containing the Novel Anions [PtX_n(CF₃)_6‐n]^2— (n = 0 ‐ 5, X = F, OH, Cl, CN) and Crystal Structure of K₂[(CF₃)₂F₂Pt(μ‐OH)₂PtF₂(CF₃)₂]·2H₂O The first syntheses of trifluoromethyl‐complexes of platinum through fluorination of cyanoplatinates are reported. The fluorination of tetracyanoplatinates(II), K₂[Pt(CN)₄], and hexacyanoplatinates(IV), K₂[Pt(CN)₆], with ClF in anhydrous HF leads after working up of the products to K₂[(CF₃)₂F₂Pt(μ‐OH)₂PtF₂(CF₃)₂]·2H₂O. The structure of the salt is determined by a X‐ray structure analysis, P2₁/c (Nr. 14), a = 11.391(2), b = 11.565(2), c = 13.391(3)Å, β = 90.32(3)°, Z = 4, R₁ = 0.0326 (I > 2σ(I)). The reaction of [Bu₄N]₂[Pt(CN)₄] with ClF in CH₂Cl₂ generates mainly cis‐[Bu₄N]₂[PtCl₂(CF₃)₄] and fac‐[Bu₄N]₂[PtCl₃(CF₃)₃], but in contrast that of [Bu₄N]₂[Pt(CN)₆] with ClF in CH₂Cl₂ results cis‐[Bu₄N]₂[PtX₂(CF₃)₄], [Bu₄N]₂[PtX(CF₃)₅] (X = F, Cl) and [Bu₄N]₂[Pt(CF₃)₆]. In the products [Bu₄N]₂[PtX_n(CF₃)_6‐n] (X = F, Cl, n = 0—3) it is possibel to exchange the fluoro‐ligands into chloro‐ and cyano‐ligands by treatment with (CH₃)₃SiCl und (CH₃)₃SiCN at 50 °C. With continuing warming the trifluoromethyl‐ligands are exchanged by chloro‐ and cyano‐ligands, while as intermediates CF₂Cl and CF₂CN ligands are formed. The identity of the new trifluoromethyl‐platinates is proved by ¹⁹⁵Pt‐ and ¹⁹F‐NMR‐spectroscopy.     

Formation of Unusual Complexes from the Reaction of [C(NMe2)3][(CO)4Fe{C(O)NMe2}] with InMe3; Crystal Structures of [C(NMe2)3]3[Fe2(CO)6(μ‐CO){μ‐InFe(CO)4(μ‐O2CNMe2)InFe(CO)4}] and [C(NMe2)3]2[{(CO)4Fe}2In(O2CNMe2)]·THF

The carbamoyl complex [C(NMe₂)₃][(CO)₄Fe{C(O)NMe₂}] ( 1 ) reacts with InMe₃ under loss of the methyl groups to produce a variety of compounds from which only the anionic cluster complexes [C(NMe₂)₃]₃[Fe₂(CO)₆(μ‐CO){μ‐InFe(CO)₄(μ‐O₂CNMe₂)InFe(CO)₄}] ([C N ₃]₃[ 2 ]) and [C(NMe₂)₃]₂[{(CO)₄Fe}₂In(O₂CNMe₂)]·THF ([C N ₃]₂[ 3 ]·THF) could be crystallized and characterized by X‐ray analyses. The anion [ 2 ]^3? has a Fe₂(CO)₉‐like structure and both anions contain the carbaminato ligand either in a bridging or in a chelating function.     

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.     

Synthesen und Charakterisierungen der ersten Tris‐ und Tetrakis(trifluormethyl)palladate(II) und ‐platinate(II), [M(CF3)3(PPh3)]— und [M(CF3)4]2— (M = Pd,Pt)

Syntheses and Characterizations of the First Tris and Tetrakis(trifluoromethyl) Palladates(II) and Platinates(II), [M(CF₃)₃(PPh₃)]^— and [M(CF₃)₄]^2— (M = Pd, Pt) Tris(trifluoromethyl)(triphenylphosphino)palladate(II) and platinate(II), [M(CF₃)₃PPh₃]^—, and the tetrakis(trifluoromethyl)metallates, [M(CF₃)₄]^2— (M = Pd, Pt), are prepared from the reactions of [MCl₂(PPh₃)₂] and Me₃SiCF₃ / [Me₄N]F or [I(CF₃)₂]^— salts in good yields. [Me₄N][M(CF₃)₃(PPh₃)] crystallize isotypically in the orthorhombic space group Pnma (no. 62) with Z = 4. The NMR spectra of the new compounds are described.     

[Me3Si(CF3)F]− and [Me3Si(CF3)2]−: Reactive Intermediates in Fluoride-Initiated Trifluoromethylation with Me3SiCF3— An NMR Study

The long-postulated reactive intermediates of polar fluoride-inititated trifluoromethylations with Me₃SiCF₃ (see scheme) were identified by NMR spectroscopy as [Me₃Si(CF₃)F]⁻ and [Me₃Si(CF₃)₂]⁻_.     

Fluoroborates by Cleavage of Trimethylamine‐bis(trifluoromethyl)boranes with NEt3 × 3 HF. Structures of C6F5(CF3)2B · NMe3, K[C6H5CH2(CF3)2BF], and K[C6H5(CF3)2BF]

Trimethylamine‐bis(trifluoromethyl)boranes R(CF₃)₂B · NMe₃ (R = cis/trans‐CF₃CF=CF ( 1/2 ), HC≡C ( 3 ), H₂C=CH ( 4 ), C₂H₅ ( 5 ), C₆H₅CH₂ ( 6 ), C₆F₅ ( 7 ), C₆H₅ ( 8 )) react with NEt₃ × 3 HF depending on the nature of R at 155–200 °C under replacement of the trimethylamine ligand to form the corresponding fluoro‐bis(trifluoromethyl)borates [R(CF₃)₂BF]^– ( 1 a/2 a – 8 a ). The structures of 7 , K[C₆H₅CH₂(CF₃)₂BF] ( K‐6 a ), and K[C₆H₅(CF₃)₂BF] ( K‐8 a ) have been investigated by single‐crystal X‐ray diffraction. In 7 the CF₃ groups make short repulsive contacts with NMe₃ and C₆F₅ entities – the B–CF₃ bonds being unusually long. The B–F bond lengths of K‐6 a and K‐8 a (1.446(3) and 1.452(2) Å, respectively) are long for a fluoroborate.     

Chirale Halbsandwich‐Pentamethylcyclopentadienyl‐Rhodium(III)‐ und Iridium(III)‐Komplexe mit Schiff‐Basen aus Salicylaldehyd und α‐Aminosäureestern [1]

Chiral Half‐sandwich Pentamethylcyclopentadienyl Rhodium(III) and Iridium(III) Complexes with Schiff Bases from Salicylaldehyde and α‐Amino Acid Esters [1] A series of diastereoisomeric half‐sandwich complexes with Schiff bases from salicylaldehyde and L‐α‐amino acid esters including chiral metal atoms, [(η⁵‐C₅H₅)(Cl)M(N,O‐Schiff base)], has been obtained from chloro bridged complexes [(η⁵‐C₅Me₅)(Cl)M(μ‐Cl)]₂ (M = Rh, Ir). Abstraction of chloride from these complexes with Ag[BF₄] or Ag[SO₃CF₃] affords the highly sensitive compounds [(η⁵‐C₅Me₅)M(N,O‐Schiff base]⁺X^? (M = Rh, Ir; X = BF₄, CF₃SO₃) to which PPh₃ can be added under formation of [(η⁵‐C₅Me₅)M(PPh₃)(N,O‐Schiff base)]⁺X^?. The diastereoisomeric ratio of the complexes ( 1 ‐ 7 and 11 ‐ 12 ) has been determined from NMR spectra.     

Strukturen von Bis(trifluormethyl)halogeno‐ und ‐thiocyanato‐mercuraten, [Hg(CF3)2X]— (X = Br,I, SCN), und ein Vergleich der Strukturparameter der CF3‐Gruppen

Structures of Bis(trifluoromethyl)halogeno and thiocyanato Mercurates, [Hg(CF₃)₂X]^— (X = Br, I, SCN), and a Comparison of the Structural Parameters of the CF₃ Groups [(18‐C‐6)K]₂[Hg(CF₃)₂SCN]₂ (1) and [P(CH₃)(C₆H₅)₃]₂[Hg(CF₃)₂X]₂ (X = Br (2) , I (3) ) are prepared and their crystal structures are determined. [(18‐C‐6)K]₂[Hg(CF₃)₂SCN]₂ (1) crystallizes in the monoclinic space group P2₁/c with Z = 2, [P(CH₃)(C₆H₅)₃]₂[Hg(CF₃)₂Br]₂ (2) in the monoclinic space group P2₁/n with Z = 2 and [P(CH₃)(C₆H₅)₃]₂[Hg(CF₃)₂I]₂ (3) in the triclinic space group P1¯ with Z = 1. In the solid state the three compounds form dimeric anions with planar Hg₂X₂ rings. The structural parameters of the Hg(CF₃)₂ units in the till now known bis(trifluoromethyl)halogeno mercurates are compared. In all compounds one nearly symmetric and one distorted CF₃ group exist. The largest differences of the C—F bond lengths is found for [(18‐C‐6)K][Hg(CF₃)₂I]. This can be regarded as the experimental evidence for the properties of trifluoromethyl mercury compounds to act as excellent difluorocarbene sources in the presence of alkali iodides.     

Über die Reaktion von Cp2TiCl2 mit [C(NMe2)3][(CO)4FeC(O)NMe2] – Kristallstruktur von [C(NMe2)3]2[FeCl4]

Concerning the Reaction of Cp₂TiCl₂ with [C(NMe₂)₃][(CO)₄FeC(O)NMe₂] – Crystal Structure of [C(NMe₂)₃]₂[FeCl₄] The title compound forms by the reaction of Cp₂TiCl₂ with [C(NMe₂)₃][(CO)₄FeC(O)NMe₂] in THF solution. It crystallizes in the space group Pbcn with a = 1 566.6(3); b = 976.4(2); c = 1 580.4(4) pm; Z = 4; R = 3.8%. Each [FeCl₄]^2? in is surrounded by eight cations. Two cations each are connected with one Cl atom by relatively short H …? Cl contacts leading to a distortion of the tetrahedral geometry of the anion.     

[P4N4F8NMe2]− – An Aminophosphazenate Ion

TAS⁺[P₄N₄F₈NMe₂]^? ( 2 ) was prepared from TAS⁺[P₄N₄F₉]^? ( 1 ) via F/NMe₂ exchange using Me₃SiNMe₂. The salt was characterised by nmr‐spectroscopy and by X‐ray crystallography. The bonding situation in the anion is briefly discussed. The structural properties of the anion are compared with those of the starting material.     

Über die Reaktionen von CH2=P(NMe2)3 mit Fe(CO)5, Cr(CO)6 und CS2; Molekülstrukturen von [MeP(NMe2)3][(CO)5CrC(O)CH=P(NMe2)3] und (CO)4Fe=C(OMe)CH=P(NMe2)3

The Reactions of CH₂=P(NMe₂)₃ with Fe(CO)₅, Cr(CO)₆, and CS₂; Molecular Structures of [MeP(NMe₂)₃][(CO)₅CrC(O)CH=P(NMe₂)₃], and (CO)₄Fe=C(OMe)CH=P(NMe₂)₃ The ylide CH₂=P(NMe₂)₃ ( 1 ) reacts with several binary transition metal carbonyls M(CO)_x to produce the corresponding salt like compounds [MeP(NMe₂)₃][(CO)_x–1MC(O)CH=P(NMe₂)₃] (M = Fe ( 3 ), Cr ( 4 )). The related reaction with CS₂ leads to the salt [MeP(NMe₂)₃][SC(S)CH=P(NMe₂)₃] ( 2 ). While 4 is thermally stable, 3 rapidly decomposes at room temperature with formation of [MeP(NMe₂)₃]₂[Fe₂(CO)₈] ( 8 ). Alkylation of 3 (at –50 °C) and 4 with MeSO₃CF₃ produces the related carbene complexes (CO)_x–1M=C(OMe)CH=P(NMe₂)₃ ( 5 ) and ( 6 ); the reaction of 3 with Me₃SiCl results in the formation of the carbene complex (CO)₄Fe=C(OSiMe₃)CH=P(NMe₂)₃ ( 7 ). 4 crystallizes in the space group P2₁2₁2₁ (No. 19) with a = 1111.1(2), b = 1476.1(3), c = 1823.1(4) pm and Z = 4. 5 crystallizes in the space group P2₁/n (No. 14) with a = 1303.6(3), b = 910.5(4), c = 1627.0(4) pm, β = 96.06(2)° and Z = 4. The compounds have been characterized by elemental analyses, NMR (¹H, ¹³C, ³¹P) and IR spectroscopy.     

Four‐ and Five‐Coordinate Gallium Complexes Stabilized by Bidentate 2‐(Dimethylaminomethyl)Pyrrole Ligand: Molecular Structures of Ga[NC4H3(CH2NMe2)‐2]3 and GaMe2[NC4H3(CH2NMe2)‐2]

Treatment of GaCl₃ with one equiv of Li[NC₄H₃(CH₂NMe₂)‐2] (n = 1, 2, 3) in diethyl ether at ?78 °C yields GaCl_3‐n[NC₄H₃(CH₂NMe₂)‐2]_n (n = 1, 1 ; n = 2, 2 ; n = 3, 3 ). Compound 1 reacts with two equiv of RLi to afford GaR₂[NC₄H₃(CH₂NMe₂)‐2] ( 4a, R=Me; 4b, R=Bu ) via transmetallation. Reacting 2 with one equiv of RLi in diethyl ether, 3 and 4 are formed via ligand redistribution. Variable temperature ¹H NMR spectroscopic experiments reveal that the five‐coordinate gallium compound 3 is fluxional and results in a coalescence temperature at 5 °C, at which ΔG^≠ is calculated at ca. 10.4 Kcal/mole. All the new compounds have been characterized by ¹H and ¹³C NMR spectroscopy and the structures of compounds 3 and 4a have also been determined by X‐ray crystallography.