Dreiecksdodekaedrische Heterotri‐ und ‐tetrametall‐Eisen–Ruthenium‐Cluster mit CpR‐ und Pn‐Liganden (n = 5, 4)

Triangulated Dodecahedral Heterotrimetallic‐ and ‐tetrametallic Iron–Ruthenium Clusters with Cp^R and P_n Ligands (n = 5, 4) The cothermolysis of [Cp*Fe(η⁵‐P₅)] ( 1 ) and [{Cp″(OC)₂Ru}₂](Ru–Ru) ( 2 ), Cp″ = C₅H₃But₂‐1,3, affords low yields of [Cp″Ru(η⁵‐P₅)] ( 3 ) and [{Cp″Ru}₂P₄] ( 4 ) as well as the triangulated dodecahedral hetero‐ and homotrimetallic clusters [{Cp″Ru}₂{Cp*Fe}P₅] ( 5 ), [{Cp″Ru}₃P₅] ( 6 ), [{Cp*Fe}₂{Cp″Ru}P₅] ( 7 ) and the tetranuclear compound [{Cp″Ru}₃{Cp*Fe}P₄] ( 8 ). X‐ray crystallographic studies show that the P₅ ligand in the distorted M₂M′P₅‐triangulated dodecahedra of 5 and 7 offers an unusual novel coordination mode derived from the educt 1 .     

Fine Tuning of Metallaborane Geometries: Chemistry of Metallaboranes of Early Transition Metals Derived from Metal Halides and Monoborane Reagents

Reaction of [Cp_nMCl_4?x] (M=V: n=x=2; M=Nb: n=1, x=0) or [Cp*TaCl₄] (Cp=η⁵‐C₅H₅, Cp*=η⁵‐C₅Me₅), with [LiBH₄?thf] at ?70 °C followed by thermolysis at 85 °C in the presence of [BH₃?thf] yielded the hydrogen‐rich metallaboranes [(CpM)₂(B₂H₆)₂] ( 1 : M=V; 2 : M = Nb) and [(Cp*Ta)₂(B₂H₆)₂] ( 3 ) in modest to high yields. Complexes 1 and 3 are the first structurally characterized compounds with a metal–metal bond bridged by two hexahydroborate (B₂H₆) groups forming a symmetrical complex. Addition of [BH₃?thf] to 3 results in formation of a metallaborane [(Cp*Ta)₂B₄H₈(μ‐BH₄)] ( 4 ) containing a tetrahydroborate ligand, [BH₄]^?, bound exo to the bicapped tetrahedral cage [(Cp*Ta)₂B₄H₈] by two Ta‐H‐B bridge bonds. The interesting structural feature of 4 is the coordination of the bridging tetrahydroborate group, which has two B? H bonds coordinated to the tantalum atoms. All these new metallaboranes have been characterized by mass, ¹H, ¹¹B, and ¹³C NMR spectroscopy and elemental analysis and the structural types were established unequivocally by crystallographic analysis of 1 – 4 .     

Heterometall-Komplexe mit E6-Liganden (E = P,As)

Heterometallic Complexes with E₆ Ligands (E = P, As) The reaction of [Cp*Co(μ-CO)]₂ 1 with the sandwich complexes [Cp*Fe(η⁵-E₅)] 2 a: E = P, 2 b: E = As in decalin at 190°C affords besides [CpCo₂E₄] 4: E = P, 7: E = As and [CpFe₂P₄] 5 the trinuclear complexes [(Cp*Fe)₂(Cp*Co)(μ-η²-P₂)(μ₃-η^1:2:1-P₂)₂] 3 as well as [(Cp*Fe)₂(Cp*Co)(μ₃-η^2:2:2-As₃)₂] 6 . With [Mo(CO)₅(thf)] 3 and 6 form in a build-up reaction the tetranuclear clusters [(Cp*Fe)₂(Cp*Co)E₆{Mo(CO)₃}] 10: E = P, 11: E = As. 3, 6 and 11 have been further characterized by an X-ray crystal structure determination.     

The Butterfly Complex [{Cp*Cr(CO)3}2(μ,η1:1-P4)] as a Versatile Ligand and Its Unexpected P1/P3 Fragmentation

The versatile coordination behavior of the P₄ butterfly complex [{Cp*Cr(CO)₃}₂(μ,η^1:1-P₄)] ( 1 ) towards Lewis acidic pentacarbonyl compounds of Cr, Mo and W is reported. The reaction of 1 with [W(CO)₄(nbd)] (nbd=norbornadiene) yields the complex [{Cp*Cr(CO)₃}₂(μ₃,η^1:1:1:1-P₄){W(CO)₄}] ( 2 ) in which 1 serves as a chelating P₄ butterfly ligand. In contrast, reactions of 1 with [M(CO)₄(nbd)] (M=Cr ( a ), Mo ( b )) result in the step-wise formation of [{Cp*Cr(CO)₂}₂(μ₃,η^3:1:1-P₄){M(CO)₅}] ( 3 a,b ) and [{Cp*Cr(CO)₂}₂-(μ₄,η^3:1:1:1-P₄){M(CO)₅}₂] ( 4 a,b ) which contain a folded cyclo-P₄ unit. Complex 4 a undergoes an unprecedented P₁/P₃-fragmentation yielding the cyclo-P₃ complex [Cp*Cr(CO)₂(η³-P₃)] ( 5 ) and the as yet unknown phosphinidene complex [Cp*Cr(CO)₂{Cr(CO)₅}₂(μ₃-P)] ( 6 ). The identity of 6 is confirmed by spectroscopic methods and by the in situ formation of [{Cp*Cr(CO)₂(tBuNC)}P{Cr(CO)₅}₂(tBuNC)] ( 7 ). DFT calculations throw light on the bonding situation of the reported products.     

Mehrkernige Eisen/Tantal‐ und Tantal‐Komplexe mit Asn‐Liganden

Polynuclear Iron/Tantalum and Tantalum Complexes with As_n Ligands Starting with [Cp@Ta(CO)₄] ( 1 ) (Cp@ = C₅H₃^tBu₂‐1,3) and As₄ or (^tBuAs)₄ ( 2 ) its thermolysis at 190 °C in decalin gives [{Cp@Ta}₂(μ‐η⁴ : η⁴‐As₈)] ( 3 ), which is also formed according to equation (2) in addition to [{Cp@Ta}₃As₆] ( 5 ). The reaction of 1 or [{Cp*(OC)₂Fe}₂] ( 6 ) with 3 affords 5 or [{Cp*Fe}{Cp@Ta}As₅] ( 8 ) demonstrating the use of 3 as As_n source. 8 can also be synthesized from 1 and [Cp*Fe(η⁵‐As₅)] ( 7 ) for which the cothermolysis of 2 and 6 gives a better yield.     

Zum Einfluß der PR3‐Liganden auf Bildung und Eigenschaften der Phosphinophosphiniden‐Komplexe [{η2‐tBu2P–P}Pt(PR3)2] und [{η2‐tBu2P1–P2}Pt(P3R3)(P4R′3)]

Coordination Chemistry of P‐rich Phosphanes and Silylphosphanes XXI The Influence of the PR₃ Ligands on Formation and Properties of the Phosphinophosphinidene Complexes [{η²‐^tBu₂P–P}Pt(PR₃)₂] and [{η²‐^tBu₂P¹–P²}Pt(P³R₃)(P⁴R′₃)] (R₃P)₂PtCl₂ and C₂H₄ yield the compounds [{η²‐C₂H₄}Pt(PR₃)₂] (PR₃ = PMe₃, PEt₃, PPhEt₂, PPh₂Et, PPh₂Me, PPh₂ⁱPr, PPh₂^tBu and P(p‐Tol)₃); which react with ^tBu₂P–P=PMe^tBu₂ to give the phosphinophosphinidene complexes [{η²‐^tBu₂P–P}Pt(PMe₃)₂], [{η²‐^tBu₂P–P}Pt(PEt₃)₂], [{η²‐^tBu₂P–P}Pt(PPhEt₂)₂], [{η²‐^tBu₂P–P}Pt(PPh₂Et)₂], [{η²‐^tBu₂P–P}Pt(PPh₂Me)₂], [{η²‐^tBu₂P–P}Pt(PPh₂ⁱPr], [{η²‐^tBu₂P–P}Pt(PPh₂^tBu)₂] and [{η²‐^tBu₂P–P}Pt(P(p‐Tol)₃)₂]. [{η²‐^tBu₂P–P}Pt(PPh₃)₂] reacts with PMe₃ and PEt₃ as well as with ^tBu₂PMe, PⁱPr₃ and P(c‐Hex)₃ by substituting one PPh₃ ligand to give [{η²‐^tBu₂P¹–P²}Pt(P³Me₃)(P⁴Ph₃)], [{η²‐^tBu₂P¹–P²}Pt(P³Ph₃)(P⁴Me₃)], [{η²‐^tBu₂P¹–P²}Pt(P³Et₃)(P⁴Ph₃)], [{η²‐^tBu₂P¹–P²}Pt(P³Me^tBu₂)(P⁴Ph₃)], [{η²‐^tBu₂P¹–P²}Pt(P³ⁱPr₃)(P⁴Ph₃)] and [{η²‐^tBu₂P¹–P²}Pt(P³(c‐Hex)₃)(P⁴Ph₃)]. With ^tBu₂PMe, [{η²‐^tBu₂P–P}Pt(P(p‐Tol)₃)₂] forms [{η²‐^tBu₂P¹–P²}Pt(P³Me^tBu₂)(P⁴(p‐Tol)₃)]. The NMR data of the compounds are given and discussed with respect to the influence of the PR₃ ligands.     

Coordination Behavior of a P4-Butterfly Complex towards Transition Metal Lewis Acids: Preservation versus Rearrangement

The reactivity of the P₄ butterfly complex [{Cp’’’Fe(CO)₂}₂(μ,η^1:1-P₄)] ( 1 , Cp’’’=η⁵-C₅H₂tBu₃) towards divalent Co, Ni and Zn salts is investigated. The reaction with the bromide salts leads to [{Cp’’’Fe(CO)₂}₂(μ₃,η^2:1:1-P₄){MBr₂}] (M=Co ( 2Co ), Ni ( 2Ni ), Zn ( 2Zn )) in which the P₄ butterfly scaffold is preserved. The use of the weakly ligated Co complex [Co(NCCH₃)₆][SbF₆]₂, results in the formation of [{(Cp’’’Fe(CO)₂)₂(μ₃,η^4:1:1-P₄)}₂Co][SbF₆]₃ ( 3 ), which represents the second example of a homoleptic-like octaphospha-metalla-sandwich complex. The formation of the threefold positively charged complex 3 occurs via redox processes, which among others also enables the formation of [{Cp’’’Fe(CO)₂}₄(μ₅,η^4:1:1:1:1-P₈){Co(CO)₂}][SbF₆] ( 4 ), bearing a rare octaphosphabicyclo[3.3.0]octane unit as a ligand. On the other hand, the reaction with [Zn(NCCH₃)₄][PF₆]₂ yields the spiro complex [{(Cp’’’Fe(CO)₂)₂(μ₃,η^2:1:1-P₄)}₂Zn][PF₆]₂ ( 5 ) under preservation of the initial structural motif.     

Functionalization of a cyclo‐P5 Ligand by Main‐Group Element Nucleophiles

Unprecedented functionalized products with an η⁴‐P₅ ring are obtained by the reaction of [Cp*Fe(η⁵‐P₅)] ( 1 ; Cp*=η⁵‐C₅Me₅) with different nucleophiles. With LiCH₂SiMe₃ and LiNMe₂, the monoanionic products [Cp*Fe(η⁴‐P₅CH₂SiMe₃)]^? and [Cp*Fe(η⁴‐P₅NMe₂)]^?, respectively, are formed. The reaction of 1 with NaNH₂ leads to the formation of the trianionic compound [{Cp*Fe(η⁴‐P₅)}₂N]^3?, whereas the reaction with LiPH₂ yields [Cp*Fe(η⁴‐P₅PH₂)]^? as the main product, with {[Cp*Fe(η⁴‐P₅)]₂PH}^2? as a byproduct. The calculated energy profile of the reactions provides a rationale for the formation of the different products.     

Rearrangement of a P4 Butterfly Complex—The Formation of a Homoleptic Phosphorus–Iron Sandwich Complex

The versatile coordination behavior of the P₄ butterfly complex [{Cp′′′Fe(CO)₂}₂(μ,η^1:1-P₄)] ( 1 , Cp′′′=η⁵-C₅H₂^tBu₃) towards different iron(II) compounds is presented. The reaction of 1 with [FeBr₂⋅dme] (dme=dimethoxyethane) leads to the chelate complex [{Cp′′′Fe(CO)₂}₂(μ₃,η^1:1:2-P₄){FeBr₂}] ( 2 ), whereas, in the reaction with [Fe(CH₃CN)₆][PF₆]₂, an unprecedented rearrangement of the P₄ butterfly structural motif leads to the cyclo-P₄ moiety in {(Cp′′′Fe(CO)₂)₂(μ₃,η^1:1:4-P₄)}₂Fe][PF₆]₂ ( 3 ). Complex 3 represents the first fully characterized “carbon-free” sandwich complex containing cyclo-P₄R₂ ligands in a homoleptic-like iron–phosphorus-containing molecule. Alternatively, 2 can be transformed into 3 by halogen abstraction and subsequent coordination of 1 . The additional isolated side products, [{Cp′′′Fe(CO)₂}₂(μ₃,η^1:1:2-P₄){Cp′′′Fe(CO)}][PF₆] ( 4 ) and [{Cp′′′Fe(CO)₂}₂(μ₃,η^1:1:4-P₄){Cp′′′Fe}][PF₆] ( 5 ), give insight into the stepwise activation of the P₄ butterfly moiety in 1 .     

E4 Butterfly Complexes (E=P,As) as Chelating Ligands

The coordination properties of new types of bidentate phosphane and arsane ligands with a narrow bite angle are reported. The reactions of [{Cp′′′Fe(CO)₂}₂(μ,η^1:1‐P₄)] ( 1 a ) with the copper salt [Cu(CH₃CN)₄][BF₄] leads, depending on the stoichiometry, to the formation of the spiro compound [{{Cp′′′Fe(CO)₂}₂(μ₃,η^1:1:1:1‐P₄)}₂Cu]⁺[BF₄]^? ( 2 ) or the monoadduct [{Cp′′′Fe(CO)₂}₂(μ₃,η^1:1:2‐P₄){Cu(MeCN)}]⁺[BF₄]^? ( 3 ). Similarly, the arsane ligand [{Cp′′′Fe(CO)₂}₂(μ,η^1:1‐As₄)] ( 1 b ) reacts with [Cu(CH₃CN)₄][BF₄] to give [{{Cp′′′Fe(CO)₂}₂(μ₃,η^1:1:1:1‐As₄)}₂Cu]⁺[BF₄]^? ( 5 ). Protonation of 1 a occurs at the “wing tip” phosphorus atoms, which is in line with the results of DFT calculations. The compounds are characterized by spectroscopic methods (heteronuclear NMR spectroscopy and IR spectrometry) and by single‐crystal X‐ray diffraction studies.     

Synthesis,Structure, Bonding,and Reactivity of Metal Complexes Comprising Diborane(4) and Diborene(2): [{Cp*Mo(CO)2}2{μ‐η2:η2‐B2H4}] and [{Cp*M(CO)2}2B2H2M(CO)4], M=Mo,W

The reaction of [(Cp*Mo)₂(μ‐Cl)₂B₂H₆] ( 1 ) with CO at room temperature led to the formation of the highly fluxional species [{Cp*Mo(CO)₂}₂{μ‐η²:η²‐B₂H₄}] ( 2 ). Compound 2, to the best of our knowledge, is the first example of a bimetallic diborane(4) conforming to a singly bridged C_s structure. Theoretical studies show that 2 mimics the Cotton dimolybdenum–alkyne complex [{CpMo(CO)₂}₂C₂H₂]. In an attempt to replace two hydrogen atoms of diborane(4) in 2 with a 2e [W(CO)₄] fragment, [{Cp*Mo(CO)₂}₂ B₂H₂W(CO)₄] ( 3 ) was isolated upon treatment with [W(CO)₅?thf]. Compound 3 shows the intriguing presence of [B₂H₂] with a short B?B length of 1.624(4) Å. We isolated the tungsten analogues of 3 , [{Cp*W(CO)₂}₂B₂H₂W(CO)₄] ( 4 ) and [{Cp*W(CO)₂}₂B₂H₂Mo(CO)₄] ( 5 ), which provided direct proof of the existence of the tungsten analogue of 2 .     

Molekül‐ und Kristallstruktur von Bis[chloro(μ‐phenylimido)(η5‐pentamethylcyclopentadienyl)tantal(IV)](Ta–Ta), [{TaCl(μ‐NPh)Cp*}2]

Molecular and Crystal Structure of Bis[chloro(μ‐phenylimido)(η⁵‐pentamethylcyclopentadienyl)tantalum(IV)](Ta–Ta), [{TaCl(μ‐NPh)Cp*}₂] Despite the steric hindrance of the central atom in [TaCl₂(NPh)Cp*] (Ph = C₆H₅, Cp* = η⁵‐C₅(CH₃)₅), caused by the Cp* ligand, the imido‐ligand takes a change in bond structure when this educt is reduced to the binuclear complex [{TaCl(μ‐NPh)Cp*}₂] in which tantalum is stabilized in the unusual oxidation state +4.     

Stabilization of Classical [B2H5]−: Structure and Bonding of [(Cp*Ta)2(B2H5)(μ‐H)L2] (Cp*=η5‐C5Me5; L=SCH2S)

The room‐temperature reaction of [Cp*TaCl₄] with LiBH₄?THF followed by addition of S₂CPPh₃ results in pentahydridodiborate species [(Cp*Ta)₂(μ,η²:η²‐B₂H₅)(μ‐H)(κ²,μ‐S₂CH₂)₂] ( 1 ), a classical [B₂H₅]^? ion stabilized by the binuclear tantalum template. Theoretical studies and bonding analysis established that the unusual stability of [B₂H₅]^? in 1 is mainly due to the stabilization of sp²‐B center by electron donation from tantalum. Reactions to replace the hydrogens attached to the diborane moiety in 1 with a 2 e {M(CO)₄} fragment (M=Mo or W) resulted in simple adducts, [{(Cp*Ta)(CH₂S₂)}₂(B₂H₅)(H){M(CO)₃}] ( 6 : M=Mo and 7 : M=W), that retained the diborane(5) unit.     

Neue 1,1′-Ferrocendichalkogenato-Komplexe des Rutheniums und Osmiums

New 1,1′-Ferrocene Dichalcogenato Complexes of Ruthenium and Osmium Both trinuclear 1,1′-ferrocene dichalcogenato complexes(¹) such as fc(E[ML_n])₂ ( 1a—c ) (with [ML_n] = Ru(CO)₂Cp*; E = S, Se, Te) and dinuclear [3]ferrocenophane derivatives of the type fcE₂[ML_n] (with [ML_n] = Ru(CO)(η⁶-C₆Me₆) ( 2a, b ), Ru(NO)Cp* ( 3a, b ) (E = S, Se) or Os(NO)Cp* ( 4a—c ) (E = S, Se, Te)) were synthesized and characterized by their IR-, ¹H- and ¹³C NMR spectra as well as their mass spectra. The molecular structure of fcS₂[Os(NO)Cp*] ( 4a ) was determined by an X-Ray structure analysis; the long Fe…?Os distance of 431.1(1)pm excludes any direct bonding interactions.     

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 ).     

Eisen-Zweikernkomplexe mit unterschiedlichen P4-Liganden

Dinuclear Iron Complexes with Different P₄ Ligands The photolysis of [Cp″Fe(CO)₂]₂ 1 (Cp″ = C₅H₃^tBu₂-1,3) and P₄ gives with successive cleavage of P? P bonds and decarbonylation the P₄ complex series [Cp″₂Fe₂P₄(CO)_{4 ? n}] 2 (n = O), 3 (n = 1), 4 (n = 2), 5 (n = 3) and 6 (n = 4) with different P₄ ligands. 4 and 6 have been further characterized by X-ray structure analyses.     

Stepwise Formation of a 1,3‐Butadiene Analogue of Mixed Heavier Group 15 Elements

The reaction of the phosphinidene complex [Cp*P{W(CO)₅}₂] ( 1 a ) with di‐tert‐butylcarboimidophosphene leads to the P? C cage compound 6 and the Lewis acid–base adduct [Cp*P{W(CO)₅}₂(CNtBu)] ( 2 a ). In contrast, the arsinidene complex shows a different reactivity. At low temperatures, the arsaphosphene complex [{W(CO)₅}{η²‐(Cp*)As?P(tBu)}{W(CO)₅}] ( 3 ) is formed. At these temperatures, 3 reacts further with a second equivalent of carboimidophosphene to form [{W(CO)₅}{η²‐{(Cp*)(tBu)P}As?P(tBu)}{W(CO)₅}] ( 5 ), probably by the insertion of a phosphinidene unit (tBuP) into an As? C bond. In contrast, at room temperature 3 reacts further by a radical‐type reaction to form [{(tBu)P?As? As?P(tBu)}{W(CO)₅}₄] ( 4 ). Compound 4 is the first example of a neutral, 1,3‐butadiene analogue containing only mixed heavier Group 15 elements. It consists of two P?As double bonds connected by arsenic atoms.     

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.     

Reaktionen von tBu2P–P=P(Me)tBu2 mit (Et3P)2NiCl2 und [{η2‐C2H4}Ni(PEt3)2]

Coordination Chemistry of P‐rich Phosphanes and Silylphosphanes. XXIII. Reactions of ^tBu₂P–P=P(Me)^tBu₂ with (Et₃P)₂NiCl₂ and [{η²‐C₂H₄}Ni(PEt₃)₂] ^tBu₂P–P=P(Me)^tBu₂ ( 1 ) forms with (Et₃P)₂NiCl₂ ( 2 ) and Na(Nph) the [μ‐(1,3 : 2,3‐η‐^tBu₂P₄^tBu₂){Ni(PEt₃)Cl}₂] ( 3 ) as main product. Using Na/Hg instead as reducing agent the Ni⁰ compounds [{η²‐^tBu₂P–P}Ni(PEt₃)₂] ( 4 ), [{η²‐^tBu₂P–P=P–P^tBu₂}Ni(PEt₃)₂] ( 5 ) and [(Et₃P)Ni(μ‐P^tBu₂)]₂ ( 6 ) with four‐membered Ni₂P₂ ring result. [{η²‐C₂H₄}Ni(PEt₃)₂] yields with 1 also 4 . The compounds were characterized by ¹H and ³¹P{¹H} NMR investigations and 3 also by a single crystal X‐ray analysis. It crystallizes triclinic in the space group P 1 with a = 1129.4(2), b = 1256.8(3), c = 1569.5(3) pm, α = 72.44(3)°, β = 70.52(3)° and γ = 74.20(3)°.     

Syntheses,Structures, and Electronic Properties of Mono- and Bimetallic Thiolato Complexes Containing Unusual Coordination Modes of Thiolato Ligands

Synthesis, bonding and chemistry of mono- and bimetallic complexes supported by chelating thiolato ligands have been established. Treatment of [Cp*VCl₂]₃ ( 1 ) with [LiBH₄ ⋅ THF] followed by the addition of ethane-1,2-dithiol led to the formation of an EPR active bimetallic vanadium thiolato complex [(Cp*V){μ-(SCH₂CH₂S)-κ²S,S′)₂{V(SCH₂CH₂S-SH)}] ( 2 ). In complex 2 , two ethane-1,2-dithiolato ligands are symmetrically coordinated to two vanadium atoms through μ-S atoms. Interestingly, when similar reactions were carried out with heavier group 5 metal precursors, such as [Cp*NbCl₄] ( 3 a ), it afforded monometallic thiolato complex [Cp*Nb(SCH₂CH₂S)(SCH₂CH₂S−CH₂S)] ( 4 a ). On the other hand, the Ta-analogue [Cp*TaCl₄] ( 3 b ) yielded thiolato species [Cp*Ta(SCH₂CH₂S)(SCH₂CH₂S−CH₂S)] ( 4 b ) and [Cp*Ta(SCH₂CH₂S) (SCH₂CH₂S−S)] ( 5 ). In complexes 4 a and 4 b , one ethane-1,2-dithiolato and one trithiolato ligand are coordinated to Nb and Ta centers, respectively. Whereas, in complex 5 , one ethane-1,2-dithiolato and one 2-disulfanylethanethiolato is coordinated to the Ta center. Moreover, the photolytic reaction of 5 with [Mo(CO)₅ ⋅ THF] yielded heterobimetallic thiolato complex [(Cp*Ta){μ-(SCH₂CH₂S)-κ²S,S′}{μ-(SCH₂CH₂S−CH₂(CH₃)S)κ²S′′ : κ¹S-′′′′ : κ¹S′′′′′}{Mo(CO)₃}] ( 6 ). All the complexes have been characterized by multinuclear NMR spectroscopy and single crystal X-ray diffraction studies. Further, computational analyses were performed to provide an insight into the bonding of these complexes.