Silver–Ethene Complexes [Ag(η2‐C2H4)n][Al(ORF)4] with n=1, 2, 3 (RF=Fluorine‐Substituted Group)

Compounds including the free or coordinated gas‐phase cations [Ag(η²‐C₂H₄)_n]⁺ (n=1–3) were stabilized with very weakly coordinating anions [A]^? (A=Al{OC(CH₃)(CF₃)₂}₄, n=1 ( 1 ); Al{OC(H)(CF₃)₂}₄, n=2 ( 3 ); Al{OC(CF₃)₃}₄, n=3 ( 5 ); {(F₃C)₃CO}₃Al‐F‐Al{OC(CF₃)₃}₃, n=3 ( 6 )). They were prepared by reaction of the respective silver(I) salts with stoichiometric amounts of ethene in CH₂Cl₂ solution. As a reference we also prepared the isobutene complex [(Me₂C?CH₂)Ag(Al{OC(CH₃)(CF₃)₂}₄)] ( 2 ). The compounds were characterized by multinuclear solution‐NMR, solid‐state MAS‐NMR, IR and Raman spectroscopy as well as by their single crystal X‐ray structures. MAS‐NMR spectroscopy shows that the [Ag(η²‐C₂H₄)₃]⁺ cation in its [Al{OC(CF₃)₃}₄]^? salt exhibits time‐averaged D_3h‐symmetry and freely rotates around its principal z‐axis in the solid state. All routine X‐ray structures (2θ_max.<55°) converged within the 3σ limit at C?C double bond lengths that were shorter or similar to that of free ethene. In contrast, the respective Raman active C?C stretching modes indicated red‐shifts of 38 to 45 cm^?1, suggesting a slight C?C bond elongation. This mismatch is owed to residual librational motion at 100 K, the temperature of the data collection, as well as the lack of high angular data owing to the anisotropic electron distribution in the ethene molecule. Therefore, a method for the extraction of the C?C distance in [M(C₂H₄)] complexes from experimental Raman data was developed and meaningful C?C distances were obtained. These spectroscopic C?C distances compare well to newly collected X‐ray data obtained at high resolution (2θ_max.=100°) and low temperature (100 K). To complement the experimental data as well as to obtain further insight into bond formation, the complexes with up to three ligands were studied theoretically. The calculations were performed with DFT (BP86/TZVPP, PBE0/TZVPP), MP2/TZVPP and partly CCSD(T)/AUG‐cc‐pVTZ methods. In most cases several isomers were considered. Additionally, [M(C₂H₄)₃] (M=Cu⁺, Ag⁺, Au⁺, Ni⁰, Pd⁰, Pt⁰, Na⁺) were investigated with AIM theory to substantiate the preference for a planar conformation and to estimate the importance of σ donation and π back donation. Comparing the group 10 and 11 analogues, we find that the lack of π back bonding in the group 11 cations is almost compensated by increased σ donation.     

Homoleptic Phosphaalkyne Complexes of Silver(I)

By employing silver salts with a weakly coordinating anion Ag[A] ([A]=[FAl{OC₁₂F₁₅}₃], [Al{OC(CF₃)₃}₄]), two phosphaalkynes could be coordinated side‐on to a bare silver(I) center to form the unprecedented homoleptic complexes [Ag(η²‐P≡CtBu)₂][FAl{OC₁₂F₁₅}₃] ( 1 ) and [Ag(η²‐P≡CtBu)₂][Al{OC(CF₃)₃}₄] ( 2 ). DFT calculations show that the perpendicular arrangement in 1 is the minimum energy structure of the coordination of the two phosphaalkynes to a silver atom, whereas for 2 a unique square‐planar coordination mode of the phosphaalkynes at Ag⁺ was found. Reactions with donor molecules yield the trigonally planar coordinated silver salts [((CH₃)₂CO)Ag(η²‐P≡CtBu)₂][FAl{OC₁₂F₁₅}₃] ( 3 ) and [(C₇H₈)₂Ag(η²‐P≡CtBu)][FAl{OC₁₂F₁₅}₃] ( 4 ). All of the compounds were comprehensively characterized in solution and in the solid state.     

The Parent Cyclopentadienyltin Cation,Its Toluene Adduct,and the Quadruple‐Decker [Sn3Cp4]2+

Truly cationic metallocenes with the parent cyclopentadienyl ligand are so far unknown for the Group 14 elements. Herein we report on an almost “naked” [SnCp]⁺ cation with the weakly coordinating [Al{OC(CF₃)₃}₄]⁻ and [{(F₃C)₃CO}₃Al−F−Al{OC(CF₃)₃}₃]⁻ anions. [SnCp][Al{OC(CF₃)₃}₄] was used to prepare the first main‐group quadruple‐decker cation [Sn₃Cp₄]²⁺ again as the [Al{OC(CF₃)₃}₄]⁻ salt. Additionally, the toluene adduct [CpSn(C₇H₈)][Al{OC(CF₃)₃}₄] was obtained.     

The Parent Cyclopentadienyltin Cation,Its Toluene Adduct,and the Quadruple‐Decker [Sn3Cp4]2+

Truly cationic metallocenes with the parent cyclopentadienyl ligand are so far unknown for the Group 14 elements. Herein we report on an almost “naked” [SnCp]⁺ cation with the weakly coordinating [Al{OC(CF₃)₃}₄]⁻ and [{(F₃C)₃CO}₃Al−F−Al{OC(CF₃)₃}₃]⁻ anions. [SnCp][Al{OC(CF₃)₃}₄] was used to prepare the first main‐group quadruple‐decker cation [Sn₃Cp₄]²⁺ again as the [Al{OC(CF₃)₃}₄]⁻ salt. Additionally, the toluene adduct [CpSn(C₇H₈)][Al{OC(CF₃)₃}₄] was obtained.     

Isomerization,Ring Expansion,and Ring Contraction of 1,3‐Diphosphete Complexes

Reactions between the 1,3‐diphosphete complex [Cp′′′Co(η⁴‐P₂C₂tBu₂)] ( 1 ) and Ag[Al{OC(CF₃)₃}₄] (Ag[pftb]) were carried out under different conditions. In CH₂Cl₂, the unprecedented 1,2‐diphosphete isomerization product [Ag₂{Cp′′′Co(μ,η⁴:η¹:η¹‐1,2‐P₂C₂tBu₂)}₂{Cp′′′Co(μ,η⁴:η¹‐1,2‐P₂C₂tBu₂)}₂]⋅2[pftb] ( 2 ) could be isolated. In diffusion experiments of 1 in n‐hexane with Ag[pftb] in CH₂Cl₂, the triphosphacobaltocenium complex [Cp′′′Co(η⁵‐P₃C₂tBu₂)][pftb] ( 4 ) and the phosphirenylium complex [Cp′′′Co(η³‐PC₂tBu₂)][pftb] ( 5 ) were obtained, showing a ring expansion and a ring contraction, respectively, under mild conditions. Moreover, addition of pyridine to the Ag complex 2 led to the new 1,2‐diphosphete complex [Cp′′′Co(η⁴‐1,2‐P₂C₂tBu₂)] ( 3 ). Compound 3 is also formed by thermolysis of 1 , making it a promising method for this type of isomerization. 1,2‐Diphosphete complexes like 3 are thermodynamically more stable but also synthetically more elusive than their 1,3‐isomer counterparts.     

Complexes of Monocationic Group 13 Elements with Pentaphospha‐ and Pentaarsaferrocene

Reactions of the sandwich complexes [Cp*Fe(η⁵‐E₅)] (Cp*=η⁵‐C₅Me₅; E=P ( 1 ), As ( 2 )) with the monovalent Group 13 metals Tl⁺, In⁺, and Ga⁺ containing the weakly coordinating anion [TEF] ([TEF]=[Al{OC(CF₃)₃}₄]^?) are described. Here, the one‐dimensional coordination polymers [M(μ,η⁵:η¹‐E₅FeCp*)₃]_n[TEF]_n (E=P, M=Tl ( 3 a ), In ( 3 b ), Ga ( 3 c ); E=As, M=Tl ( 4 a ), In ( 4 b )) are obtained as sole products in good yields. All products were analyzed by single‐crystal X‐ray diffraction, revealing a similar assembly of the products with η⁵‐bound E₅ ligands and very weak σ‐interactions between one P or As atom of the ring to the neighbored Group 13 metal cation. By exchanging the [TEF] anion of 4 a for the larger [FAl] anion ([FAl]=[FAl{OC₆F₁₀(C₆F₅)}₃]^?), the coordination compound [Tl{(η⁵‐As₅)FeCp*}₃][FAl] ( 5 ) without any σ‐interactions of the As₅‐ring is obtained. All products are readily soluble in CH₂Cl₂ and exhibit a dynamic coordination behavior in solution, which is supported by NMR spectroscopy and ESI‐MS spectrometry as well as by osmometric molecular‐weight determination. For a better understanding of the proceeding equilibrium DFT calculations of the cationic complexes were performed for the gas phase and in solution. Furthermore, the ³¹P{¹H} magic‐angle spinning (MAS) NMR spectra of 3 a–c are presented and the first crystal structure of the starting material 2 was determined.     

Highly Dynamic Coordination Behavior of Pn Ligand Complexes towards “Naked” Cu+ Cations

Reactions of Cu⁺ containing the weakly coordinating anion [Al{OC(CF₃)₃}₄]^? with the polyphosphorus complexes [{CpMo(CO)₂}₂(μ,η²:η²‐P₂)] ( A ), [CpM(CO)₂(η³‐P₃)] (M=Cr( B1 ), Mo ( B2 )), and [Cp*Fe(η⁵‐P₅)] ( C ) are presented. The X‐ray structures of the products revealed mononuclear ( 4 ) and dinuclear ( 1 , 2 , 3 ) Cu^I complexes, as well as the one‐dimensional coordination polymer ( 5 a ) containing an unprecedented [Cu₂( C )₃]²⁺ paddle‐wheel building block. All products are readily soluble in CH₂Cl₂ and exhibit fast dynamic coordination behavior in solution indicated by variable temperature ³¹P{¹H} NMR spectroscopy.     

Metal‐Deficient Supramolecule Based on a Fivefold‐Symmetric Building Block

An unprecedented cationic supramolecule [(Cp′′Fe(η⁵‐P₅))₁₂{CuNCMe}₈]⁸⁺ 2.66 nm in diameter was selectively isolated as a salt of the weakly coordinating anion [Al{OC(CF₃)₃}₄]^? for the first time and characterized by X‐ray structure analysis, PXRD, NMR spectroscopy, and mass spectrometry. Its metal‐deficient core contains the lowest possible number of Cu atoms to connect 12 pentaphosphaferrocene units, providing a supramolecule with fullerene topology which, topologically, also represents the simplest homologue in the family of metal‐deficient pentaphosphaferrocene‐based supramolecules [{Cp^RFe(η⁵‐P₅)}₁₂(CuX)_20?n]. The 12 vacant metal sites between the cyclo‐P₅ rings, the largest number attained to date, make this compound a facile precursor for potential inner and outer modifications of the core as well as for functionalization via the substitution of labile acetonitrile ligands.     

Mixed Organometallic–Organic Hybrid Assemblies Based on the Diarsene Complex [Cp2Mo2(CO)4(μ,η2-As2)], AgI Salts and N-Donor Organic Molecules

The reaction of the organometallic diarsene complex [Cp₂Mo₂(CO)₄(η²-As₂)] ( 1 ) with Ag[Al{OC(CF₃)₃}₄] (Ag[TEF]) yielded the Ag^I monomer [Ag(η²- 1 )₃][TEF] ( 2 ). This compound exhibits dynamic behavior in solution, which allows directed selective synthesis of unprecedented organometallic–organic hybrid assemblies upon its reaction with N-donor organic molecules by a stepwise pathway, which is supported by DFT calculations. Accordingly, the reaction of 2 with 2,2′-bipyrimidine ( L1 ) yielded the dicationic molecular compound [{(η²- 1 )₂Ag}₂(μ- L1 )][TEF]₂ ( 3 ) or the 1D polymer [{(η²- 1 )Ag}(μ- L1 )]_n[TEF]_n ( 4 ) depending on the ratio of the reactants. However, its reactions with the pyridine-based linkers 4,4′-bipyridine ( L2 ), 1,2-bis(4-pyridyl)ethylene ( L3 ) and 1,2-bis(4-pyridyl)ethyne ( L4 ) allowed the formation of the 2D polymers [{(η²- 1 )Ag}₂(μ- Lx )₃]_n[TEF]_2n [ Lx=L2 ( 5 ), L3 ( 6 ), L4 ( 7 ), respectively]. Additionally, this concept was extended to step-by-step one-pot reactions of 1 , [Ag(CH₃CN)₃][Al{OC(CF₃)₂(CCl₃)}₄] ([Ag(CH₃CN)₃][TEF^Cl]) and linkers L2 – L4 to produce the 2D polymers [{(η²- 1 )Ag}₂(μ, Lx )₃]_n[TEF^Cl]_2n [ Lx = L2 ( 8 ), L3 ( 9 ), L4 ( 10 ), respectively].     

The Versatile Coordination Modes of Monophosphine‐o‐Carborane in the Formation of Iridium and Rhodium Complexes: Synthesis,Reactivity, and Characterization

Monophosphine‐o‐carborane has four competitive coordination modes when it coordinates to metal centers. To explore the structural transitions driven by these competitive coordination modes, a series of monophosphine‐o‐carborane Ir,Rh complexes were synthesized and characterized. [Cp*M(Cl)₂{1‐(PPh₂)‐1,2‐C₂B₁₀H₁₁}] (M=Ir ( 1 a ), Rh ( 1 b ); Cp*=η⁵‐C₅Me₅), [Cp*Ir(H){7‐(PPh₂)‐7,8‐C₂B₉H₁₁}] ( 2 a ), and [1‐(PPh₂)‐3‐(η⁵‐Cp*)‐3,1,2‐MC₂B₉H₁₀] (M=Ir ( 3 a ), Rh ( 3 b )) can be all prepared directly by the reaction of 1‐(PPh₂)‐1,2‐C₂B₁₀H₁₁ with dimeric complexes [(Cp*MCl₂)₂] (M=Ir, Rh) under different conditions. Compound 3 b was treated with AgOTf (OTf=CF₃SO₃^?) to afford the tetranuclear metallacarborane [Ag₂(thf)₂(OTf)₂{1‐(PPh₂)‐3‐(η⁵‐Cp*)‐3,1,2‐RhC₂B₉H₁₀}₂] ( 4 b ). The arylphosphine group in 3 a and 3 b was functionalized by elemental sulfur (1 equiv) in the presence of Et₃N to afford [1‐{(S)PPh₂}‐3‐(η⁵‐Cp*)‐3,1,2‐MC₂B₉H₁₀] (M=Ir ( 5 a ), Rh ( 5 b )). Additionally, the 1‐(PPh₂)‐1,2‐C₂B₁₀H₁₁ ligand was functionalized by elemental sulfur (2 equiv) and then treated with [(Cp*IrCl₂)₂], thus resulting in two 16‐electron complexes [Cp*Ir(7‐{(S)PPh₂}‐8‐S‐7,8‐C₂B₉H₉)] ( 6 a ) and [Cp*Ir(7‐{(S)PPh₂}‐8‐S‐9‐OCH₃‐7,8‐C₂B₉H₉)] ( 7 a ). Compound 6 a further reacted with nBuPPh₂, thereby leading to 18‐electron complex [Cp*Ir(nBuPPh₂)(7‐{(S)PPh₂}‐8‐S‐7,8‐C₂B₉H₁₀)] ( 8 a ). The influences of other factors on structural transitions or the formation of targeted compounds, including reaction temperature and solvent, were also explored.     

Reaction of S2CC(PPh3)2 with Silver Salts Containing Weakly Coordinating Anions; Preparation and Crystal Structures of [Ag6{S2CC(PPh3)2}4][BF4]6 · 9.75CH2CL2 and [Ag4{S2CC(PPh3)2}4][Al{OC(CF3)3}4]4 · 4.25C2H4Cl2

The betain‐like carbodiphosphorane CS₂ adduct S₂CC(PPh₃)₂ ( 1 ) reacts with Ag(I) salts which contain weakly coordinating anions such as [BF₄]^? or [Al{OC(CF₃)₃}₄]^? to produce the cluster compounds [Ag₆{S₂CC(PPh₃)₂}₄][BF₄]₆ ( 2 ) and [Ag₄{S₂CC(PPh₃)₂}₄][Al{OC(CF₃)₃}₄]₄ ( 3 ), respectively, as orange yellow crystals containing solvent molecules. In the solid state the Ag₄ unit in 3 forms a tetrahedron, and in the Ag₆ core of 2 two of the opposite edges of the tetrahedron are bridged by Ag⁺ ions. The clusters are held together by argentophilic interactions, and each sulfur atom of 1 is coordinated to four (as in 2 ) or three (as in 3 ) silver atoms. The compounds are characterized by IR and ³¹P NMR spectroscopic studies and by X‐ray diffraction analyses.     

Reaction of Pentelidene Complexes with Diazoalkanes: Stabilization of Parent 2,3‐Dipnictabutadienes

The reaction of the phosphinidene complex [Cp*P{W(CO)₅}₂] ( 1 a ) with diphenyldiazomethane leads to [{W(CO)₅}Cp*P=NN{W(CO)₅}=CPh₂] ( 2 ). Compound 2 is a rare example of a phosphadiazadiene ligand (R‐P=N?N=CR′R′′) complex. At temperatures above 0 °C, 2 decomposes into the complex [{W(CO)₅}PCp*{N(H)N=CPh₂)₂] ( 3 ), among other species. The reaction of the pentelidene complexes [Cp*E{W(CO)₅}₂] (E=P, As) with diazomethane (CH₂NN) proceeds differently. For the arsinidene complex ( 1 b ), only the arsaalkene complex 4 b [{W(CO)₅}₂{η^1:2‐(Cp*)As=CH₂}] is formed. The reaction with the phosphinidene complex ( 1 a ) results in three products, the two phosphaalkene complexes [{W(CO)₅}₂{η^1:2‐(R)P=CH₂}] ( 4 a : R=Cp*, 5 : R=H) and the triazaphosphole derivative [{W(CO)₅}P(Cp*)‐CH₂‐N{W(CO)₅}=N‐N(N=CH₂)] ( 6 a ). The phosphaalkene complex ( 4 a ) and the arsaalkene complex ( 4 b ) are not stable at room temperature and decompose to the complexes [{W(CO)₅}₄(CH₂=E?E=CH₂)] ( 7 a : E=P, 7 b : E=As), which are the first examples of complexes with parent 2,3‐diphospha‐1,3‐butadiene and 2,3‐diarsa‐1,3‐butadiene ligands.     

Ring Expansions of Nonpolar Polyphosphorus Rings

The reaction of the phosphinidene complex [Cp*P{W(CO)₅}₂] ( 1 a ) (Cp*=C₅Me₅) with the anionic cyclo-P_n ligand complex [(η³-P₃)Nb(ODipp)₃]⁻ ( 2 , Dipp=2,6-diisopropylphenyl) resulted in the formation of [{W(CO)₅}₂{μ₃,η^3:1:1-P₄Cp*}Nb(ODipp)₃]⁻ ( 3 ), which represents an unprecedented example of a ring expansion of a polyphosphorus-ligand complex initiated by a phosphinidene complex. Furthermore, the reaction of the pnictinidene complexes [Cp*E{W(CO)₅}₂] (E=P: 1 a , As: 1 b ) with the neutral complex [Cp′′′Co(η⁴-P₄)] (Cp′′′=1,2,4-tBu₃C₅H₂) led to a cyclo-P₄E ring (E=P, As) through the insertion of the pentel atom into the cyclo-P₄ ligand. Starting from 1 a , the two isomers [Cp′′′Co(μ₃,η^4:1:1-P₅Cp*){W(CO)₅}₂] ( 5 a , b ), and from 1 b , the three isomers [Cp′′′Co(μ₃,η^4:1:1-AsP₄Cp*){W(CO)₅}₂] ( 6 a – c ) with unprecedented cyclo-P₄E ligands (E=P, As) were isolated. The complexes 6 a – c represent unique examples of ring expansions which lead to new mixed five-membered cyclo-P₄As ligands. The possible reaction pathways for the formation of 5 a , b and 6 a – c were investigated by a combination of temperature-dependent ³¹P{¹H} NMR studies and DFT calculations.     

The Potential of the Diarsene Complex [(C5H5)2Mo2(CO)4(μ,η2-As2)] as a Connector Between Silver Ions

The reaction of the organometallic diarsene complex [Cp₂Mo₂(CO)₄(μ,η²-As₂)] ( B ) (Cp = C₅H₅) with Ag[FAl{OC₆F₁₀(C₆F₅)}₃] (Ag[FAl]) and Ag[Al{OC(CF₃)₃}₄] (Ag[TEF]), respectively, yields three unprecedented supramolecular assemblies [(η²- B )₄Ag₂][FAl]₂ ( 4 ), [(μ,η¹:η²- B )₃(η²- B )₂Ag₃][TEF]₃ ( 5 ) and [(μ,η¹:η²- B )₄Ag₃][TEF]₃ ( 6 ). These products are only composed of the complexes B and Ag^I. Moreover, compounds 5 and 6 are the only supramolecular assemblies featuring B as a linking unit, and the first examples of [Ag^I]₃ units stabilized by organometallic bichelating ligands. According to DFT calculations, complex B coordinates to metal centers through both the As lone pair and the As−As σ-bond thus showing this unique feature of this diarsene ligand.     

Remote Multiproton Storage within a Pyrrolide‐Pincer‐Type Ligand

A chemically non‐innocent pyrrole‐based trianionic (ONO)^3? pincer ligand within [(pyr‐ONO)TiCl(thf)₂] ( 2 ) can access the dianionic [(3H‐pyr‐ONO)TiCl₂(thf)] ( 1‐THF ) and monoanionic [(3H,4H‐pyr‐ONO)TiCl₂(OEt₂)][B{3,5‐(CF₃)₂C₆H₃}₄] ( 3‐Et₂O ) states through remote protonation of the pyrrole γ‐C π‐bonds. The homoleptic [(3H‐pyr‐ONO)₂Zr] ( 4 ) was synthesized and characterized by X‐ray diffraction and NMR spectroscopy in solution. The protonation of 4 by [H(OEt₂)₂][B{C₆H₃(CF₃)₂}₄] yields [(3H,4H‐pyr‐ONO)(3H‐pyr‐ONO)Zr][B{3,5‐(CF₃)₂C₆H₃}₄] ( 5 ), thus demonstrating the storage of three protons.     

Metal Derivatives of 1,3‐Imidazolidine‐2‐thione with Divalent d10 Metal Ions (Zn–Hg) : Synthesis and Structures

Reactions of divalent Zn‐Hg metal ions with 1,3‐imidazolidine‐2‐thione (imdtH₂) in 1 : 2 molar ratio have formed monomeric complexes, [Zn(η¹‐S‐imdtH₂)₂(OAc)₂] ( 1 ), [Cd((η¹‐SimdtH₂)₂I₂] ( 2 ), [Cd(η¹‐S‐imdtH₂)₂Br₂] ( 3 ), and [Hg(η¹‐S‐imdtH₂)₂I₂] ( 4 ). Complexes 1 – 4 , have been characterized by elemental analysis (C, H, N), spectroscopy (IR, ¹H, NMR) and x‐ray crystallography ( 1 ‐ 4 ). Hydrogen bonding between oxygen of acetate and imino hydrogen of ligand, {N(2)–H(2C)···O(2)^#} in 1 , ring CH and imino hydrogen, {C(2A)–H(2A)···Br(2)^#} in 3 have formed H‐bonded dimers. Similarly, the interactions between molecular units of complexes 2 and 4 have yielded 2D polymers. The polymerization occurs via intermolecular interactions between thione sulfur and imino hydrogen, {N(2)–H(2)···S(1)^#}, imino hydrogen and the iodine atom, {NH(1)···I(2)^#} in 2 and imino hydrogen – iodine atom {N(2A)–H(2A)···I(2)} and I···I interaction in 4 . Crystal data: [Zn(η¹‐S‐imdtH₂)₂(OAc)₂] ( 1 ), C₁₀H₁₈N₄O₄S₂Zn, orthorhombic, Pbcn, a = 9.3854(7) Å, b = 12.4647(10) Å, c = 13.2263(11) Å; V = 1547.3(2) ų, Z = 4, R = 0.0280 [Cd((η¹‐S‐imdtH₂)₂I₂] ( 2 ), C₆H₁₂CdI₂N₄S₂, orthorhombic, Pnma, a = 13.8487(10) Å, b = 14.4232(11) Å, c = 7.0659(5) Å; Z = 4, V = 1411.36(18) ų, R = 0.0186.     

Different Complexation Behavior of P‐Functionalized Ferrocene Derivatives Towards SnCl2, SnCl4 and SnPh2Cl2: Auto‐ionization and Redox‐Type Reactions

The novel phosphonyl‐substituted ferrocene derivatives [Fe(η⁵‐Cp)(η⁵‐C₅H₃{P(O)(O‐iPr)₂}₂‐1,2)] ( Fc^1,2 ) and [Fe{η⁵‐C₅H₄P(O)(O‐iPr)₂}₂] ( Fc^1,1′ ) react with SnCl₂, SnCl₄, and SnPh₂Cl₂, giving the corresponding complexes [(Fc^1,2)₂SnCl][SnCl₃] ( 1 ), [{(Fc^1,1′)SnCl₂}_n] ( 2 ), [(Fc^1,1′)SnCl₄] ( 3 ), [{(Fc^1,1′)SnPh₂Cl₂}_n] ( 4 ), and [(Fc^1,2)SnCl₄] ( 5 ), respectively. The compounds are characterized by elemental analyses, ¹H, ¹³C, ³¹P, ¹¹⁹Sn NMR and IR spectroscopy, ³¹P and ¹¹⁹Sn CP‐MAS NMR spectroscopy, cyclovoltammetry, electrospray ionization mass spectrometry, and single‐crystal as well as powder X‐ray diffraction analyses. The experimental work is accompanied by DFT calculations, which help to shed light on the origin for the different reaction behavior of Fc^1,1′ and Fc^1,2 towards tin(II) chloride.     

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.     

Synthesis and Reactivity of a Cyclooctatetraene-Like Polyphosphorus Ligand Complex [Cyclo-P8]

The thermolysis of Cp′′′Ta(CO)₄ with white phosphorus (P₄) gives access to [{Cp′′′Ta}₂(μ,η^{2 : 2 : 2 : 2 : 1 : 1}-P₈)] ( A ), representing the first complex containing a cyclooctatetraene-like (COT) cyclo-P₈ ligand. While ring sizes of n >6 have remained elusive for cyclo-P_n structural motifs, the choice of the transition metal, co-ligand and reaction conditions allowed the isolation of A . Reactivity investigations reveal its versatile coordination behaviour as well as its redox properties. Oxidation leads to dimerization to afford [{Cp′′′Ta}₄(μ₄,η^{2 : 2 : 2 : 2 : 2 : 2 : 2 : 2 : 1 : 1 : 1 : 1}-P₁₆)][TEF]₂ ( 4 , TEF=[Al(OC{CF₃}₃)₄]⁻). Reduction, however, leads to the fission of one P−P bond in A followed by rapid dimerization to form [K@[2.2.2]cryptand]₂[{Cp′′′Ta}₄(μ₄,η^{2 : 2 : 2 : 2 : 2 : 2 : 2 : 2 : 1 : 1 : 1 : 1}-P₁₆)] ( 5 ), which features an unprecedented chain-type P₁₆ ligand. Lastly, A serves as a P₂ synthon, via ring contraction to the triple-decker complex [{Cp′′′Ta}₂(μ,η^{6 : 6}-P₆)] ( B ).     

Pentafulvenkomplexe des Titans — Synthese,Struktur und Fluktuierendes Verhalten von Cp′Ti{η6‐C5H4=C(p‐Tol)2}Cl (Cp′ = Cp*, Cp)

Complexes of Titanium — Synthesis, Structure, and Fluxional Behaviour of CpTi{η⁶‐C₅H₄=C(p‐Tol)₂}Cl (Cp′ = Cp*, Cp) The reaction of Cp′TiCl₃ (C′ = Cp* or Cp) with magnesium and 6, 6‐di‐para‐tolylpentafulvene generates good yields of pentafulvene complexes Cp*Ti{η⁶‐C₅H₄=C(p‐Tol)₂}Cl ( 4 ) and CpTi{η⁶‐C₅H₄=C(p‐Tol)₂}Cl ( 5 ), respectively. The crystal and molecular structure of 4 have been determined from X‐ray data and exhibits compared to known η⁶‐pentafulvene complexes an unusual large Ti—C(p‐Tol)₂ (Fv)‐distance (2.535(5)Å) evoked by the bulky substituents at the exocyclic carbon. Dynamic ¹H‐NMR and spin saturation transfer experiments point out a rotation of the fulvene ligand around the Ti—Ct2 axis (Ct2 = centroid of the fulvene ring carbon atoms) with an activation barrier ΔG^≠_C = 60.6 ± 0.5 kJ mol⁻¹ (T_C = 314 ± 2 K). For 5 this barrier is significantly larger. Analogous dynamic behaviour is well known for diene complexes, but to our knowledge, it is here first‐time described for a pentafulvene complex.