Umsetzungen von Cp*NbCl4 und Cp*TaCl4 mit Trimethylsilyl‐azid,Me3Si‐N3. Molekülstrukturen der bis(azido)‐oxo‐verbrückten Komplexe [Cp*NbCl(N3)(μ‐N3)]2(μ‐O) und [Cp*TaCl2(μ‐N3)]2(μ‐O) (Cp* = Pentamethylcyclopentadienyl)

Reactions of Cp*NbCl₄ and Cp*TaCl₄ with Trimethylsilyl‐azide, Me₃Si‐N₃. Molecular Structures of the Bis(azido)‐Oxo‐Bridged Complexes [Cp*NbCl(N₃)(μ‐N₃)]₂(μ‐O) and [Cp*TaCl₂(μ‐N₃)]₂(μ‐O) (Cp* = Pentamethylcyclopentadienyl) The chloro ligands in Cp*TaCl₄ (1c) can be stepwise substituted for azido ligands by reactions with trimethylsilyl azide, Me₃Si‐N₃ (A) , to generate the complete series of the bis(azido)‐bridged dimers [Cp*TaCl_3‐n(N₃)_n(μ‐N₃)]₂ ( n = 0 (2c) , n = 1 (3c) , n = 2 (4c) and n = 3 (5c) ). If the solvent CH₂Cl₂ contains traces of water, an additional oxo bridge is incorporated to give [Cp*‐TaCl₂(μ‐N₃)]₂(μ‐O) (6c) or [Cp*TaCl(N₃)(μ‐N₃)]₂(μ‐O) (7c) , respectively. Both 6c and 7c are also formed in stoichiometric reactions from [Cp*TaCl₂(μ‐OH)]₂(μ‐O) (8c) and A . Analogous reactions of Cp*NbCl₄ (1b) with A were used to prepare the azide‐rich dinuclear products [Cp*NbCl_3‐n(N₃)_n(μ‐N₃)]₂ (n = 2 (4b) , and n = 3 (5b) ), and [Cp*NbCl(N₃)(μ‐N₃)]₂(μ‐O) (7b) . The mononuclear complex Cp*Ta(N₃)Me₃ (10c) is obtained from Cp*Ta(Cl)Me₃ and A . All azido complexes were characterised by their IR as well as their ¹H and ¹³C NMR spectra; X‐ray crystal structure analyses are available for 6c and 7b .     

Neue Azidokomplexe des Tantals(V). Synthese und Molekülstruktur der Zweikernverbindungen [Cp*TaCl(N3)(μ‐N3)]2(μ‐O) und [Cp*Ta(N3)3(μ‐N3)]2 (Cp* = Pentamethylcyclopentadienyl)

New Azido Complexes of Tantalum(V). Synthesis and Molecular Structure of the Dinuclear Compounds [Cp*TaCl(N₃)(μ‐N₃)]₂(μ‐O) and [Cp*Ta(N₃)₃(μ‐N₃)]₂ (Cp* = Pentamethylcyclopentadienyl) The reaction of Cp*TaCl₄ ( 1 ) with an excess of trimethylsilyl azide (Me₃Si–N₃) leads to azide‐rich dinuclear complexes which contain both terminal and bridging azido ligands. The oxo complex [Cp*TaCl(N₃)(μ‐N₃)]₂(μ‐O) ( 4 ) was formed in dichloromethane in the presence of traces of water, whereas [Cp*Ta(N₃)₃(μ‐N₃)]₂ ( 5 ) was obtained from boiling toluene after several days. According to the X‐ray structure determinations the Ta…Ta distance in 4 (314,5 pm) is considerably shorter than in 5 (382,2 pm).     

Azido-Derivate des Pentamethylcyclopentadienyl-Vanadium(IV)-Fragments. Molekülstrukturen der Zweikernkomplexe [Cp*VCl(N3)(μ-N3)]2 und [Cp*V(N3)2(μ-N3)]2

Azido Derivatives of the Pentamethylcyclopentadienyl Vanadium(IV)-Fragment. Molecular Structures of the Binuclear Complexes [Cp*VCl(N₃)(μ-N₃)]₂ and [Cp*V(N₃)₂(μ-N₃)]₂ The stepwise reaction of Cp*VCl₃ with excess trimethylsilyl azide (Me₃Si–N₃) in solution leads to the paramagnetic, azido-bridged complexes [Cp*VCl₂(μ-N₃)]₂ ( 3 ), [Cp*VCl(N₃)(μ-N₃)]₂ ( 4 ) and [Cp*V(N₃)₂(μ-N₃)]₂ ( 5 ) which were characterized by their IR and mass spectra. The azide-rich binuclear complex 5 is also formed if a pentane solution of Cp*V(CO)₄ is stirred in the presence of excess Me₃Si–N₃ in an open vessel. According to the X-ray structure analyses both 4 and 5 are centrosymmetric molecules with a planar V(N)₂V four-membered ring. In the absence of free trimethylsilyl azide, solutions of 3 – 5 lose dinitrogen slowly; in the presence of traces of air, 5 is thereby converted to the diamagnetic, oxo-bridged complex [Cp*V(O)(N₃)]₂(μ-O) ( 6 ).     

[{Cp″Co}3(μ3-P)(μ3-PSe)], ein Dreikerncluster mit einem PSe-Liganden

[{Cp″Co}₃(μ₃-P)(μ₃-PSe)], a Trinuclear Cluster with a PSe Ligand The cothermolysis of [Cp″Co(CO)₂] ( 1 ), Cp″ = C₅H₃Bu-1.3, and P₄ gives besides [{Cp″Co}₃(μ₃-P)₂] ( 2 ) the cobalt P_n complexes [{Cp″Co}₄(μ₃-P)₄] ( 3 ) and [{Cp″Co}₂(μ, η^2:2-P₂)₂] ( 4 ). 2 can be oxidized with grey selenium forming [{Cp″Co}₃(μ₃-P)(μ₃-PSe)] ( 5 ) and [{Cp″Co}₃(μ₃-PSe)₂] ( 6 ), complexes with the hitherto unknown PSe ligand. The crystal structure of 5 reveals a trigonal-bipyramidal Co₃P₂ skeleton with one μ₃-PSe ligand.     

Unerwartete Reduktion von [Cp*TaCl4(PH2R)] (R = But,Cy, Ad,Ph, 2,4,6‐Me3C6H2; Cp* = C5Me5) durch Reaktion mit DBU – Molekülstruktur von [(DBU)H][Cp*TaCl4] (DBU = 1,8‐Diazabicyclo[5.4.0]undec‐7‐en)

Unexpected Reduction of [Cp*TaCl₄(PH₂R)] (R = Bu^t, Cy, Ad, Ph, 2,4,6‐Me₃C₆H₂; Cp* = C₅Me₅) by Reaction with DBU – Molecular Structure of [(DBU)H][Cp*TaCl₄] (DBU = 1,8‐diazabicyclo[5.4.0]undec‐7‐ene) [Cp*TaCl₄(PH₂R)] (R = Bu^t, Cy, Ad, Ph, 2,4,6‐Me₃C₆H₂ (Mes); Cp* = C₅Me₅) react with DBU in an internal redox reaction with formation of [(DBU)H][Cp*TaCl₄] ( 1 ) (DBU = 1,8‐diazabicyclo[5.4.0]undec‐7‐ene) and the corresponding diphosphane (P₂H₂R₂) or decomposition products thereof. 1 was characterised spectroscopically and by crystal structure determination. In the solid state, hydrogen bonding between the (DBU)H cation and one chloro ligand of the anion is observed.     

Multiple Coordination of Metal Atoms to Arenes: The Coordination of Six Ruthenium Atoms to Naphthalene-1,8-diyl in [Ru6(μ6-C10H6)(μ3-PPh)(CO)14]

Six ruthenium atoms are coordinated to the naphthalene-1,8-diyl ligand in the cluster [Ru₆(CO)₁₄(C₁₀H₆)(PPh)] through two Ru−C σ bonds, two η², and two η³ interactions (section of structure depicted on the right). The complex could, therefore, serve as a model for the chemisorption of naphthalene on a step-site on a (111) metal surface.     

Synthesis and Structure of the Tetrameric [Cp*V(μ‐F)2]4 (Cp* = C5Me5); Preparation of the Imido Molybdenum Fluoride [(2,6‐i‐Pr2C6H3N)2MoF2] · THF and the Structural Investigation of [(2,6‐i‐Pr2C6H3N)6Mo4(μ3‐F)2Me2(μ‐O)4]

Treating [Cp*V(μ‐Cl)₂]₃ (Cp* = C₅Me₅) and [(2,6‐i‐Pr₂C₆H₃N)₂MoMe₂], respectively, with Me₃SnF afforded the title compounds [Cp*V(μ‐F)₂]₄ ( 1 ) and [(2,6‐i‐Pr₂C₆H₃N)₂MoF₂] · THF ( 2 ). 1 has a tetrameric structure, in which four V atoms can be regarded as being arranged at the vertices of a distorted tetrahedron, with four long edges bridged by one F atom and each of the other two short edges bridged by two F atoms with a mean V–F bond length of 2.00 Å. A hydrolyzed product of 2 , [(2,6‐i‐Pr₂C₆H₃N)₆Mo₄(μ₃‐F)₂Me₂(μ‐O)₄] ( 3 ) was characterized by elemental analyses and X‐ray single crystal study. The X‐ray diffraction analysis reveals that 3 has a unique tetranuclear structure, containing two five and two six coordinated Mo atoms connecting each other by four μ‐O and two μ₃‐F atoms. The geometries around the two Mo atoms can be described having distorted trigonal bipyramidal and distorted octahedral coordination spheres, respectively. The Mo–(μ‐O) bond lengths are 1.813 Å (average) for five coordinated Mo atoms and 2.030 Å (average) for those of six coordinated, respectively, indicating an additional π bonding between five coordinated Mo atoms and the μ‐O atoms. The Mo–(μ₃‐F) distances range from 2.291 to 2.352 Å.     

Zur Reaktivität von Titanocenkomplexen [Ti(Cp′)2(η2‐Me3SiC≡CSiMe3)] (Cp′ = Cp,Cp*) gegenüber Benzoldicarbonsäuren

On the Reactivity of Titanocene Complexes [Ti(Cp′)₂(η²‐Me₃SiC≡CSiMe₃)] (Cp′ = Cp, Cp*) towards Benzenedicarboxylic Acids Titanocene complexes [Ti(Cp′)₂(BTMSA)] ( 1a , Cp′ = Cp = η⁵‐C₅H₅; 1b , Cp′ = Cp* = η⁵‐C₅Me₅; BTMSA = Me₃SiC≡CSiMe₃) were found to react with iodine and methyl iodide yielding [Ti(Cp′)₂(μ‐I)₂] ( 2a / b ; a refers to Cp′ = Cp and b to Cp′ = Cp*), [Ti(Cp′)₂I₂] ( 3a / b ) and [Ti(Cp′)₂(Me)I] ( 4a / b ), respectively. In contrast to 2a , complex 2b proved to be highly moisture sensitive yielding with cleavage of HCp* [{Ti(Cp*)I}₂(μ‐O)] ( 7 ). The corresponding reactions of 1a / b with p‐cresol and thiophenol resulted in the formation of [Ti(Cp′)₂{O(p‐Tol)}₂] ( 5a / b ) and [Ti(Cp′)₂(SPh)₂] ( 6a / b ), respectively. Reactions of 1a and 1b with 1,n‐benzenedicarboxylic acids (n = 2–4) resulted in the formation of dinuclear titanium(III) complexes of the type [{Ti(Cp′)₂}₂{μ‐1,n‐(O₂C)₂C₆H₄}] (n = 2, 8a / b ; n = 3, 9a / b ; n = 4, 10a / b ). All complexes were fully characterized analytically and spectroscopically. Furthermore, complexes 7 , 8b , 9a ·THF, 10a / b were also be characterized by single‐crystal X‐ray diffraction analyses.     

[Ph2P(O)CH2Im][F3B(μ‐OH)BF3]. Erste strukturanalytische Charakterisierung des Hexafluoro(μ‐hydroxo)diborat‐Ions [1]

[Ph₂P(O)CH₂Im][F₃B(μ‐OH)BF₃]. First Structural Characterization of the Hexafluoro(μ‐hydroxo)diborate Ion [1] The hexafluoro(μ‐hydroxo)diborate ion has been isolated as it's Ph₂P(O)CH₂Im salt [Im = 2‐(1, 3, 4, 5‐tetramethylimidazolio)] ( 2 ) through basic hydrolysis of [Ph₂P(OBF₃)CH₂Im]BF₄ ( 1 ). The crystal structure of 2 · CH₂Cl₂ reveals the presence of ion pairs linked by unsymmetrical O‐H‐O hydrogen bonds.     

Kristallstruktur des Molybdän(V)‐Imido‐Komplexes [MoCl3(NtBu)(H2NtBu)]2 · 1/2 C7H8

Crystal Structure of the Molybdenum(V) Complex [MoCl₃(N^tBu)(H₂N^tBu)]₂ · ¹/₂ C₇H₈ Green moisture sensitive single crystals of [MoCl₃(N^tBu)(H₂N^tBu)]₂ ( 1 · ¹/₂ C₇H₈) have been prepared from molybdenum pentachloride with Me₂Si(HN^tBu)₂ in toluene solution; they were suitable for a crystal structure determination. 1 · ¹/₂ C₇H₈: Space group P 1, Z = 2, lattice dimensions at –83 °C: a = 696.9(1), b = 1470.9(2), c = 1579.0(2) pm, α = 96.673(13)°, β = 92.014(14)°, γ = 94.852(14)°, R = 0.0321. 1 forms centrosymmetric molecules in which the molybdenum atoms are linked by two μ‐Cl‐bridges with MoCl bond lengths of 245.7 and 270.2 pm in average of the two crystallographically independent individuals. The longer MoCl bond is in trans‐position to the nitrogen atom of the imido ligand (MoN distance 169.0 pm, MoNC bond angle 167.0° in average).     

On the Reaction of [(CO)3Fe(μ‐Me2NCO)2Fe(CO)2(NHMe2)] with Chelating Ligands — X‐Ray Structures of New Binuclear μ‐Carbamoyl Complexes

Reaction of the binuclear μ‐carbamoyl complex [(CO)₃Fe(μ‐Me₂NCO)₂Fe(CO)₂(HNMe₂)] ( 1 ) in toluene with the chelating ligands Ph₂PCH₂PPh₂ (dppm) and Ph₂PCH₂CH₂PPh₂ (dppe) gives different results. With dppm only the complex [(CO)₃Fe(μ‐Me₂NCO)₂Fe(CO)₂(dppm)] ( 3 ) with a dangling ligand is obtained under replacement of amine, whereas with dppe depending on the reaction conditions up to three compounds are found. A 1 : 1 mixture of the educts generates the related complex [(CO)₃Fe(μ‐Me₂NCO)₂Fe(CO)₂(dppe)] ( 4 ) together with the tetranuclear complex [{(CO)₃Fe(μ‐Me₂NCO)₂Fe(CO)₂}₂(dppe)] (5 ). 4 slowly converts into [(CO)₃Fe(μ‐Me₂NCO)₂Fe(CO)(dppe)] ( 6 ) with dppe acting as a chelating ligand. 6 is the first compound in this series in which one of the five CO groups is replaced by another donor. A 2 : 1 molar ratio of 1 and dppe quantitatively produces 5 . Addition of CO to a solution of 6 proceeds under slow reversible conversion of the complex into 4 . The compounds were characterized by the usual spectroscopic methods; 3 , 5 and 6 were also studied by X‐ray diffraction analyses.     

Heterodinukleare Komplexe: Synthese und Kristallstrukturen von [RuRh(μ‐CO)(CO)4(μ‐PtBu2)(tBu2PH)], [RuRh(μ‐CO)(CO)3(μ‐PtBu2)(μ‐Ph2PCH2PPh2)] und [CoRh(CO)4(μ‐H)(μ‐PtBu2)(tBu2PH)]

Heterobinuclear Complexes: Synthesis and X‐ray Crystal Structures of [RuRh(μ‐CO)(CO)₄(μ‐P^tBu₂)(^tBu₂PH)], [RuRh(μ‐CO)(CO)₃(μ‐P^tBu₂)(μ‐Ph₂PCH₂PPh₂)], and [CoRh(CO)₄(μ‐H)(μ‐P^tBu₂)(^tBu₂PH)] [Ru₃Rh(CO)₇(μ₃‐H)(μ‐P^tBu₂)₂(^tBu₂PH)(μ‐Cl)₂] ( 2 ) yields by cluster degradation under CO pressure as main product the heterobinuclear complex [RuRh(μ‐CO)(CO)₄(μ‐P^tBu₂)(^tBu₂PH)] ( 4 ). The compound crystallizes in the orthorhombic space group Pcab with a = 15.6802(15), b = 28.953(3), c = 11.8419(19) Å and V = 5376.2(11) ų. The reaction of 4 with dppm (Ph₂PCH₂PPh₂) in THF at room temperature affords in good yields [RuRh(μ‐CO)(CO)₃(μ‐P^tBu₂)(μ‐dppm)] ( 7 ). 7 crystallizes in the triclinic space group P 1 with a = 9.7503(19), b = 13.399(3), c = 15.823(3) Å and V = 1854.6 ų. Moreover single crystals of [CoRh(CO)₄(μ‐H)(μ‐P^tBu₂)(^tBu₂PH)] ( 9 ) could be obtained and the single‐crystal X‐ray structure analysis revealed that 9 crystallizes in the monoclinic space group P2₁/a with a = 11.611(2), b = 13.333(2), c = 18.186(3) Å and V = 2693.0(8) ų.     

Synthesis and Structure of the First Lanthanide Complex with the Bridging,Antiaromatic 2,2′-Bipyridine Dianion: [{Yb(μ2-N2C10H8)(thf)2}3]

The two-electron reduction of 2,2′-bipyridine with naphthaleneytterbium resulted in the formation of the ytterbium complex [{Yb(μ₂-bipy)(thf)₂}₃] (see picture) in which antiaromatic 2,2′-bipyridine dianions bridge the ytterbium atoms in a novel μ₂-η²:η⁴ fashion.     

Aktivierung von Schwefelkohlenstoff an Trirutheniumclustern: Synthese und Kristallstruktur von [Ru3(CO)5(μ‐H)2(μ‐PCy2)(μ‐Ph2PCH2PPh2){μ‐η2‐PCy2C(S)}(μ3‐S)] und [Ru3(CO)5(CS)(μ‐H)(μ‐PtBu2)(μ‐PCy2)2(μ3‐S)]

Activation of Carbon Disulfide on Triruthenium Clusters: Synthesis and X‐Ray Crystal Structure Analysis of [Ru₃(CO)₅(μ‐H)₂(μ‐PCy₂)(μ‐Ph₂PCH₂PPh₂){μ‐η²‐PCy₂C(S)}(μ₃‐S)] and [Ru₃(CO)₅(CS)(μ‐H)(μ‐P^tBu₂)(μ‐PCy₂)₂(μ₃‐S)] [Ru₃(CO)₆(μ‐H)₂(μ‐PCy₂)₂(μ‐dppm)] ( 1 ) (dppm = Ph₂PCH₂PPh₂) reacts under mild conditions with CS₂ and yields by oxidative decarbonylation and insertion of CS into one phosphido bridge the opened 50 VE‐cluster [Ru₃(CO)₅(μ‐H)₂(μ‐PCy₂)(μ‐dppm){μ‐η²‐PCy₂C(S)}(μ₃‐S)] ( 2 ) with only two M–M bonds. The compound 2 crystallizes in the triclinic space group P 1 with a = 19.093(3), b = 12.2883(12), c = 20.098(3) Å; α = 84.65(3), β = 77.21(3), γ = 81.87(3)° and V = 2790.7(11) ų. The reaction of [Ru₃(CO)₇(μ‐H)(μ‐P^tBu₂)(μ‐PCy₂)₂] ( 3 ) with CS₂ in refluxing toluene affords the 50 VE‐cluster [Ru₃(CO)₅(CS)(μ‐H)(μ‐P^tBu₂)(μ‐PCy₂)₂(μ₃‐S)] ( 4 ). The compound cristallizes in the monoclinic space group P 2₁/a with a = 19.093(3), b = 12.2883(12), c = 20.098(3) Å; β = 104.223(16)° and V = 4570.9(10) ų. Although in the solid state structure one elongated Ru–Ru bond has been found the complex 4 can be considered by means of the ³¹P‐NMR data as an electron‐rich metal cluster.     

Binuclear CpV,Cp*V,and Cp*Ta Complexes containing Organochalcogenolato Bridges, μ‐ER (E = Sulfur,Selenium, Tellurium; R = Methyl,Phenyl, and Ferrocenyl)

Photolysis of the halfsandwich tetracarbonylmetal complexes CpV(CO)₄, Cp*V(CO)₄ and Cp*Ta(CO)₄ in solution in the presence of di(organyl)dichalcogenides E₂R₂ (E = S, Se, Te; R = Me, Ph, Fc) leads to diamagnetic doubly organochalcogenolato‐bridged compounds, [Cp⁽⁾M(CO)₂(μ‐ER)]₂. According to the X‐ray structure determinations carried out for [CpV(CO)₂(μ‐TeMe)]₂, [Cp*V(CO)₂(μ‐TePh)]₂ and [Cp*Ta(CO)₂(μ‐SPh)]₂, the molecular framework consists of a folded M₂(μ‐ER)₂ ring with the cyclopentadienyl ligands in cis‐configuration and the organyl substituents R in a syn‐equatorial arrangement, thus forming a bowl‐shaped molecule with the four terminal CO ligands protruding into the inner sphere. The M…M distances (in the range between 305 and 330 pm) are not considered to indicate direct bonding interactions. The vanadium complexes [Cp⁽⁾V(CO)₂(μ‐ER)]₂ are completely decarbonylated in the presence of an excess of E₂R₂ in boiling toluene, and in many cases the paramagnetic quadruply‐bridged products, [CpV(μ‐ER)₂]₂, can be isolated.     

The new polynuclear titanium(IV) complex [(Cp*TiCl)(μ‐O)2(Cp*Ti)2(μ‐O)(μ‐O)2]2Ti (Cp* is η5‐C5Me5)

A new polynuclear titanium(IV) complex, dichloro­deca‐μ₂‐oxo‐hexa­kis­(penta­methyl­cyclo­penta­dien­yl)hexa­titanium(IV), [Ti₆(C₁₀H₁₅)₆Cl₂O₁₀], has been synthesized by hydro­lysis of a titanium complex bearing an N‐(2‐hydr­oxy‐3,5‐dimethyl­benz­yl)diethano­lamine Mannich ligand. The mol­ecule has two O‐bridged Ti₃O₃ rings linked to two similar rings through a tetra­hedrally O‐coordinated Ti atom. All Ti atoms except the central one are coordinated to penta­methyl­cyclo­penta­dien­yl (Cp*) ligands. The Cp* ligands are arranged with approximate symmetry with respect to the Ti/O/Cl core.