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.     

Cyclopentadienyl Dicarbonyl Iron‐Bismuth Compounds – Synthesis,Structure, and Reactivity

Abstract. The cyclopentadienyl‐substituted iron‐bismuth complexes [{Cp(CO)₂Fe}BiCl₂] ( 1 ), [{Cp(CO)₂Fe}BiBr₂] ( 2 ), [{Cp′′(CO)₂Fe}BiBr₂] ( 3 ) and [{Cp*(CO)₂Fe}BiBr₂] ( 4 ) were prepared with high yields starting from [Cp^x(CO)₂Fe]₂ [Cp^x = C₅H₅ (Cp), C₅H₃‐1, 3‐tBu₂ (Cp′′), C₅Me₅ (Cp*)] and the corresponding bismuth halides. The single crystal X‐ray structure analyses of compounds 2 – 4 are reported. Comparison of their solubility demonstrates that the steric hindrance in this type of compounds is only slightly higher for compound 3 compared with compound 2 but significantly lower compared with the Cp* derivative 4 . Compounds 1 – 4 react with nucleophililic reagents such as KOtBu, NaOCH₂CH₂OCH₃, and NaOSiMe₃ as well as with water in the presence of an amine to give a mixture of [{Cp^x(CO)₂Fe}BiX] (X = Cl, Br) and [{Cp^x(CO)₂Fe}₃Bi]. In case of a reaction with nBu₄NCl and DMAP (dimethylaminopyridine) no such dismutation is observed. Instead the complexes [{Cp(CO)₂Fe}BiBr₂(DMAP)₂] ( 5 ), [NnBu₄]₂[{{Cp(CO)₂Fe}BiBr₃}₂] ( 6 ) and [NnBu₄]₂[{{Cp(CO)₂Fe}BiCl₃}₂] ( 7 ) were isolated and characterized by single‐crystal X‐ray diffraction.     

Niob- und Tantalkomplexe mit P2- und P4-Liganden

Niobium and Tantalum Complexes with P₂ and P₄ Ligands The photolysis of [Cp″Ta(CO)₄] 1 (Cp″ = C₅H₃^tBu₂?1,3) and P₄ affords Cp″(CO)₂Ta(η⁴?P₄) 2 , [{Cp″(CO)Ta}₂(m??η^2:2?P₂)₂] 3 and [Cp₃″(CO)₃Ta₃(P₂)₂] 4 . In a photochemical reaction 2 and [Cp*Nb(CO)₄] 5 form [{Cp*(CO)Nb}{Cp″(CO)Ta}(m??η^2:2?P₂)₂] 6 and [{Cp*(CO)₂Nb} {Cp*Nb}{Cp″(CO)Ta}(m?₃?η^2:1:1?P₂)₂] 7 , a compound with the novel m?₃?η^2:2:1?P₂-coordination mode. The reaction of 2 and [Cp*Co(C₂H₄)₂] 8 leads to [{Cp*Co} {Cp″(CO)Ta}(m??η^2:2?P₂)₂] 9 , a heteronuclear complex with an ?early”? and a ?late”? transition metal. Complexes 2, 3, 7 and 9 have been further characterized by X-ray structure analyses.     

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 .     

Syntheses,Crystal Structures,and Reactivity of [enH]4[Sn2Se6]·en, [enH]4[Sn2Te6]·en and [enH]4[Sn2S6]: Known Anions within Novel Coordination Spheres obtained by Novel Synthesis Routes

The hexachalcogenodistannates K₆[Sn^III₂Se₆] or Li₄[Sn^IV₂Te₆]·8en were recently reported to simultaneously act as mild oxidants and chalcogenide sources in reactions with CoCl₂/LiCp* (Cp* = pentamethylcyclopentadienide) while the Sn—E (E = Se, Te) fragment is not kept in the products, e.g. [(Cp*Co)₃(μ₃‐Se)₂], [(Cp*Co)₃(μ₃‐Se)₂][Cl₂Co(μ₂‐Cl)₂Li(thf)₂] or [(Cp*Co)₄(μ₃‐Te)₄]. In search of related reagents with possibly different reaction behavior, we isolated and crystallographically characterized isotypic compounds [enH]₄[Sn^IV₂Se₆]�en ( 1 ), and [enH]₄[Sn^IV₂Te₆]·en ( 2 ) (en = 1, 2‐diaminoethane), that result from an uncommon disproportion/re‐arrangement reaction: distannate(III) K₆[Sn₂E₆] (E = Se, Te) was reacted with en·2HCl to yield 1 or 2 under disproportion of Sn^III to Sn^II and Sn^IV. Another pathway was necessary to synthesize the respective but solvent‐free thiostannate [enH]₄ [Sn^IV₂S₆] ( 3 ), since the phase “K₆[Sn₂S₆]” is unknown. This second method started out from SnCl₄·2THF and S(SiMe₃)₂ in en solution. However, using E(SiMe₃)₂ (E = Se, Te) instead of S(SiMe₃)₂, 1 and 2 are also obtained this way. 1—3 are the first chalcogenostannates that exhibit exclusively [enH]⁺ counterions. The compounds were characterized by means of X‐ray crystallography and NMR spectroscopy. They seem to be suitable for reactions towards group 8‐10 metal complexes. Preliminary experiments indicate that the binary anions 1 — 3 coordinated by 1‐aminoethylammonium ions react more slowly compared to the anionic phases tested until now.     

Synthesis and Structure of the Bicyclic [Sn4Se11]6– Anion in Na6Sn4Se11 · 22 H2O

Na₆Sn₄Se₁₁ · 22 H₂O can be crystallised at –8 °C as yellow‐orange needles from the 1 : 2 H₂O/CH₃OH mother liquor of a superheated reaction mixture of NaOH(s), Sn and Se. The bicyclic [Sn₄Se₁₁]^6– anion exhibits crystallographic C₂ symmetry and is composed of corner‐bridged SnSe₄ tetrahedra. Two opposite tin atoms of an Sn₄Se₄ 8‐membered ring are linked by a common Se atom, thereby affording two 6‐membered boat‐shaped Sn₃Se₃ rings with a shared Sn–Se–Sn bridging unit. [Sn₄Se₁₁]^6– thus represents the immediate precursor of the well‐known adamantane‐like [Sn₄Se₁₀]^4– anion.     

tBuC≡P als Edukt für die Bildung eines Rhenium‐Zweikernkomplexes mit einem verbrückenden,chiralen Phosphinidenoxid‐Liganden

^tBuC≡P as a Synthon for the Formation of a Dinuclear Rhenium Complex with a Bridging and Chiral Phosphinidene Oxide Ligand The one‐pot reaction of [{Cp*(OC)₂Re}₂] (Re = Re) ( 3 ) with ^tBuC≡P ( 4 ) and the subsequent oxidation with (Me₃Si)₂O₂ ( 5 ) affords [Re(CO)₂C₅Me₄CH₂{μ‐HC(Bu^t)P(O)}Re(CO)₂Cp*] ( 6 ), a dinuclear rhenium complex with a bridging and chiral phosphinidene oxide ligand. Its structure was confirmed by an X‐ray crystal structure determination.     

Synthese,Struktur und Eigenschaften von [(C4H9)2NH2]4[Sn2Se6], [(C4H9)2NH2]4[Sn4Se10] · 2 H2O und [(C3H7)3NH]2[Sn3Se7]

About Selenidostannates. I Synthesis, Structure, and Properties of [Sn₂Se₆]^4–, [Sn₄Se₁₀]^4–, and [Sn₃Se₇]^2– The selenidostannates [(C₄H₉)₂NH₂]₄Sn₂Se₆ · H₂O ( I ), [(C₄H₉)₂NH₂]₄Sn₄Se₁₀ · 2 H₂O ( II ) und [(C₃H₇)₃NH]₂Sn₃Se₇ ( III ) were prepared by hydrothermal syntheses from the elements and the amines. I crystallizes in the monoclinic spacegroup P2₁/n (a = 1262.9(3) pm, b = 1851.3(4) pm, c = 2305.2(4) pm, β = 104.13(3)° and Z = 4). The [Sn₂Se₆]^4– anion consists of two edge‐sharing tetrahedra. II crystallizes in the orthorhombic spacegroup Pna2₁ (a = 2080.3(4) pm, b = 1308.2(3) pm, c = 2263.5(5) pm and Z = 4). The anion is formed from four SnSe₄ tetrahedra which are joined by common corners to the adamantane cage [Sn₄Se₁₀]^4–. III crystallizes in the orthorhombic spacegroup Pbcn (a = 1371.1(3) pm, b = 2285.4(5) pm, c = 2194.7(4) pm and Z = 8). The anion is a chain, built from edge‐sharing [Sn₃Se₅Se_4/2]^2– units, in which two corner sharing tetrahedra are connected to a trigonal bipyramid by an edge of one and a corner of the other tetrahedron. The results of the TG/DSC measurements and of temperature dependent X‐ray diffractograms reveal that I and II decompose at first by release of minor quantities of triethylammonium to compounds with layer structure and larger cell dimensions. At still higher temperature the rest of triethylammonium and H₂Se is evolved, leaving SnSe₂ and Se in the bulk. The former decomposes partially at the highest temperature to SnSe. In the measurements of III the complex intermediate compound was not observed. III decomposes directly to SnSe₂.     

Neue metallorganisch substituierte Indium–Stickstoff-Verbindungen. Synthese und Kristallstrukturen von [{Cp(CO)3Mo}2InN(SiMe3)2] und [{Cp(CO)3Mo}In{N(SiMe3)2}2]

New Organometallic Indium Nitrogen Compounds. Synthesis and Crystal Structures of [{Cp(CO)₃Mo}₂InN(SiMe₃)₂] and [{Cp(CO)₃Mo}In{N(SiMe₃)₂}₂] The reaction of [{Cp(CO)₃Mo}₂InCl] with LiN · (SiMe₃)₂ leads to the formation of [{Cp(CO)₃Mo}₂InN · (SiMe₃)₂] ( 1 ). 1 is monomeric and it contains an indium atom which is coordinated in a trigonal planar manner by two {Cp(CO)₃Mo} fragments and a N(SiMe₃)₂ group. The corresponding bis-amide [{Cp(CO)₃Mo}In{N(SiMe₃)₂}₂] ( 2 ) is prepared by the reaction of [{Cp(CO)₃Mo}InCl₂] with two equivalents of LiN(SiMe₃)₂. In analogy to 1, 2 is monomeric and it contains an indium atom in a trigonal planar coordination.     

[{Cp(CO)3Mo}4In4(PSiMe3)4], Ein metallorganisch substituiertes In4P4-Heterokuban

[{Cp(CO)₃Mo}₄In₄(PSiMe₃)₄], an Organometallic In₄P₄-Heterocubane [{Cp(CO)₃Mo}InCl₂] reacts with P(SiMe₃)₃ in THF as solvent to form [{Cp(CO)₃Mo}₄In₄(PSiMe₃)₄] 1. 1 crystallizes in the space group P1 . The lattice constants (at 208 K) are: a = 1 770.1(6), b = 1 490.3(6), c = 1 317.5(6) pm, α = 76.59(4),β = 88.54(3), γ = 88.98(3)°. According to the crystal structure analysis, 1 contains a slightly distorted In₄P₄-core with an alternating arrangement of In and P atoms. The In atoms are coordinated roughly tetrahedrally by three PSiMe₃ groups (In–P: 256.9(3)–262.3(3) pm) and a {Cp(CO)₃Mo} substituent (In? Mo: 278.0(2)–279.5(3) pm).     

Hydroxoverbindungen. 10. Über die Natriumoxohydroxostannate(II) Na4[Sn4O(OH)10] und Na2[Sn2O(OH)4]

Hydroxo Compounds. 10. The Sodium Oxohydroxostannates(II) Na₄[Sn₄O(OH)₁₀] and Na₂[Sn₂O(OH)₄] Na₄[Sn₄O(OH)₁₀] = Na₄[Sn(OH)₃]₂[Sn₂O(OH)₄] ( I ) and Na₂[Sn₂O(OH)₄] ( II ) have now been doubtlessly characterized as the first Na-hydroxostannates(II). I crystallizes monoclinic in P2₁/n (a = 1522.4(5) pm, b = 830.0(2) pm, c = 1276.0(3) pm, β = 104.8(2)°, Z = 4, R = 0.047, 1137 I_hkl); II crystallizes orthorhombic in P2₁2₁2₁ (a = 1450(2) pm, b = 1665(2) pm, c = 590.7(8) pm, Z = 8, R = 0.042, 1208 I_hkl). II is identical with the compound which was described up to now as “Na[Sn(OH)₃]”. The new compounds contain the complex anions [Sn(OH)₃]^? and [Sn₂O(OH)₄]^2?, whose structures are now proved. The oxotetrahydroxo-distannate(II) anion [Sn₂O(OH)₄]^2? exhibits a syn-conformation with respect to the projection along the (Sn? Sn) vector. The two compounds crystallize with pronounced layer structures, which show direct topotactical relations with one another as well as with SnO. This relates closely to the fast formation of SnO from crystals of I and II .     

Einkristall-Röntgenstrukturanalysen an Verbindungen mit kovalenter Metall–Metall-Bindung. IV. Die Molekül- und KristallStruktur von Mn2(CO)8[μ-Sn(Br)Mn(CO)5]2

Single Crystal X-Ray Analysis of Compounds with Covalent Metal—Metal Bonds. IV. Molecular and Crystal Structure of Mn₂(CO)₈[μ-Sn(Br) Mn(CO)₅]₂ Mn₂(CO)₈[μ-Sn(Br)Mn(CO)₅]₂ crystallizes in the monoclinic crystal system (a = 881.7 pm; b = 1237.6 pm; c = 1551.1 pm und β = 63.54°) in the space group P2₁/n with two formula units in the cell. The structure was solved by means of 2601 symmetrically independent reflections using the heavy atom method. The central molecule fragment of Mn₂(CO)₈ · [μ-Sn(Br)Mn(CO)₅]₂ consists of a planar Mn₂Sn₂ rhombus with a Mn? Mn-bond (Mn? Mn = 308.6(1) pm) across the metal ring. Besides the bonds to both Mn ring atoms each Sn(IV) atom has a terminal bond to a Br and Mn(CO)₅ ligand, building up a distorted tetrahedron around the Sn(IV) atom. The terminal ligands in Mn₂(CO)₈[μ-Sn(Br)Mn(CO)₅]₂ are in transposition with respect to the ring. The mean values for the remaining bond distances are: Sn? Mn = 263.0(1) pm; Sn? Br = 255.4(1) pm; Mn? C = 184.4(6) pm; C? O = 113.3(7) pm. A comparison of the Sn₂Mn₂ ring with similar metal rings has been given.     

Schwache Sn…I‐Wechselwirkungen in den Kristallstrukturen der Iodostannate [SnI4]2– und [SnI3]–

Weak Sn…I Interactions in the Crystal Structures of the Iodostannates [SnI₄]^2– and [SnI₃]^– Iodostannate complexes can be crystallized from SnI₂ solutions in polar organic solvents by precipitation with large counterions. Thereby isolated anions as well as one, two or three‐dimensional polymeric anionic substructures are established, in which SnI₃^– and SnI₄^2– groups are linked by weak Sn…I interactions. Examples are the iodostannates [Me₃N–(CH₂)₂–NMe₃][SnI₄] ( 1 ), (Ph₄P)₂[Sn₂I₆] ( 2 ), [Me₃N–(CH₂)₂–NMe₃][Sn₂I₆] ( 3 ), [Fe(dmf)₆][SnI₃]₂ ( 4 ) and (Pr₄N)[SnI₃] ( 5 ), which have been characterized by single crystal X‐ray diffraction. [Me₃N–(CH₂)₂–NMe₃][SnI₄] ( 1 ): a = 671.6(2), b = 1373.3(4), c = 2046.6(9) pm, V = 1887.7(11) · 10⁶ pm³, space group Pbcm;(Ph₄P)₂[Sn₂I₆] ( 2 ): a = 1168.05(6), b = 717.06(4), c = 3093.40(10) pm, β = 101.202(4)°, V = 2541.6(2) · 10⁶ pm³, space group P2₁/n;[Me₃N–(CH₂)₂–NMe₃][Sn₂I₆] ( 3 ): a = 695.58(4), b = 1748.30(8), c = 987.12(5) pm, β = 92.789(6)°, V = 1199.00(11) · 10⁶ pm³, space group P2₁/c;[Fe(dmf)₆][SnI₃]₂ ( 4 ): a = 884.99(8), b = 1019.04(8), c = 1218.20(8) pm, α = 92.715(7), β = 105.826(7), γ = 98.241(7), V = 1041.7(1) · 10⁶ pm³, space group P1;(Pr₄N)[SnI₃] ( 5 ): a = 912.6(2), b = 1205.1(2), c = 1885.4(3) pm, V = 2073.5(7) · 10⁶ pm³, space group P2₁2₁2₁.     

Synthetic and Structural Studies on the Cyclic Bis(amino)stannylenes Sn[(NR)2C10H6‐1, 8] and their Reactions with SnCl2 or Si[(NCH2But)2C6H4‐1, 2] (R = SiMe3 or CH2But)

Treatment of {HNR}₂C₁₀H₆‐1, 8 [R = SiMe₃ ( 1 ), CH₂Bu^t ( 2 )] with Sn[N(SiMe₃)₂]₂ afforded the cyclic stannylene Sn[{NR}₂C₁₀H₆‐1, 8] [R = SiMe₃ ( 3 ), CH₂Bu^t ( 4 )]. From 3 and SnCl₂ in THF and crystallisation from toluene, the product was the crystalline tetracyclic compound ( 5 ) as the (toluene)_0.5‐solvate. Reaction of 4 with the silylene Si[(NCH₂Bu^t)₂C₆H₄‐1, 2] ( 6 ) [abbreviated as Si(NN)] in benzene and crystallisation in presence of Et₂O furnished the crystalline tricyclic complex Sn[{Si(NCH₂Bu^t)₂C₆H₄‐1′, 2′}₂‐{(NCH₂Bu^t)₂C₁₀H₆‐1, 8}] ( 7 ) as the Et₂O‐solvate. Complex 5 slowly dissociated into its factors 3 and SnCl₂ in toluene, but rapidly in THF. Solutions of 7 in C₆D₆, C₇D₈ or THF‐d₈, studied by multinuclear, variable temperature NMR spectroscopy, revealed the presence of an equilibrium between 8 (an isomer of 7 , in which the skeletal atoms of the eight‐membered ring were , rather than the of 7 ) and 4 + 2 Si(NN), with 8 dominant in PhMe but not in THF; additionally 8 was shown to be fluxional and solutions of 8 in C₆D₆ or C₇D₈ decomposed to give the silane Si(NN)[(NCH₂Bu^t)₂C₁₀H₆‐1, 8], 6 and Sn metal. The X‐ray structures of 3 , 5 and 7 are presented.     

[{Cp*(OC)2Re}2(μ‐POH)], ein Zweikernkomplex mit einem verbrückenden Hydroxiphosphiniden‐Liganden

[{Cp*(OC)₂Re}₂(μ‐POH)], a Dinuclear Complex with a Bridging Hydroxiphosphinidene Ligand The reaction of [{Cp*(OC)₂Re}₄(μ₄‐η¹ : η¹ : η¹ : η¹‐P₂)] ( 1 ) with 0.1 m HCl gives [{Cp*(OC)₂Re}₂(μ‐POH)] ( 2 ), the X‐ray crystal structure of which reveals a dinuclear rhenium complex with a μ‐POH (hydroxiphosphinidene) ligand.     

Alkaline Metal Stannide‐Stannates: ‘Double Salts’ with Zintl Sn and Stannate SnO Anions

Using the reduction of tin oxides with the elemental alkaline metals rubidium and cesium, stannide stannates have been synthesized which contain Zintl anions [Sn₄]^4— (i.e. Sn^—I) and isolated oxostannate ions [SnO₃]^4— (i.e. Sn^+II) together with further oxide ions for charge compensation. The crystal structures of the three compounds A_23.6Sn_7.4O_13.2 = A_23.6[Sn₄][SnO₃]_3.4[O]₃ (A = Rb 1a : monoclinic, P2₁/c, a = 2174.2(6), b = 1137.0(6), c = 2373.6(6) pm, β = 116.11(2)°, Z = 4, R1 = 0.056; A = Cs 1b : monoclinic, P2₁/c, a = 2042.6(6), b = 1185.4(3), c = 2481.1(7) pm, β = 97.06(2)°, Z = 4, R1 = 0.075) and Cs₄₈Sn₂₀O₂₁ = Cs₄₈[Sn₄]₄[SnO₃]₄[O]₇[O₂] ( 2 monoclinic, P2/c, a = 1701.8(3), b = 877.4(2), c = 4556.9(7) pm, β= 101.47(1)°, R1 = 0.093) have been determined on the basis of single crystal data. The transparency of the compounds allowed the recording of raman spectra of the anion [Sn₄]^4—. The ¹¹⁹Sn Moessbauer spectrum of the rubidium compound shows a singulet in good agreement with RbSn, overlapping a doublet caused by Sn²⁺ in the asymmetrical environment of the strongly electronegative oxygen ligands of SnO.     

Direct Observation by Electrospray Ionization Mass Spectrometry of [Cp*RhMo3O8(OMe)5]−, a Key Intermediate in the Formation of the Double-Bookshelf-Type Oxide Cluster [(Cp*Rh)2Mo6O20(OMe)2]2−

The use of methanol as solvent is essential for the formation of the double-bookshelf-type oxide cluster [(Cp*Rh)₂Mo₆O₂₀(OMe)₂]²⁻ from [{Cp*Rh(μ-Cl)Cl}₂] and four equivalents of [Mo₂O₇]²⁻. The reaction proceeds via [Cp*RhMo₃O₈(OMe)₅]⁻. The proposed structure for this key intermediate (shown schematically) is supported by electrospray ionization mass spectrometry and labeling experiments with CD₃OD as solvent. Cp*=η⁵-C₅Me₅.     

Synthesis and Structure of [Sn4Se11]6–, [Sn2Se52–], and [Sn3Se72–] – Model Anions for the Solventothermal Reaction Pathway to Lamellar Selenidostannates(IV)

Reaction of A₂CO₃ (A = K, Rb) with Sn and Se in an H₂O/CH₃OH mixture at 115–130°C affords the isotypic selenidostannates(IV) A₆Sn₄Se₁₁ _. xH₂O (A = K, x = 8) 1 and 2 whose discrete [Sn₄Se₁₁]^6– anions each contain two corner‐bridged ditetrahedral [Sn₂Se₆]^4– species. Similar reaction conditions with A = Cs afford Cs₂Sn₂Se₅ _. H₂O ( 3a ) and Cs₂Sn₂Se₅ ( 3b ) in which such [Sn₂Se₆]^4– building blocks are connected through common Se atoms into infinite [Sn₂Se₅^2–] chains. The [Sn₃Se₇^2–] ribbons of (Et₄N)₂Sn₃Se₇ ( 4 ), formed by treating (Et₄N)I with Sn and Se in methanol at 130°C, can be regarded as resulting from the condensation of [Sn₂Se₅^2–] chains with molecular [SnSe₄]^4– anions. The anions [Sn₄Se₁₁]^6–, [Sn₂Se₅^2–], and [Sn₃Se₇^2–] represent the products of individual reaction steps on the potential condensation pathway of [Sn₂Se₆]^4– to the lamellar selenidostannates(IV) [Sn₄Se₉^2–] or [Sn₃Se₇^2–].     

Mono- und Di-t-butylcyclopentadienyl-Carbonyl-Komplexe des Eisens und Molybdäns. Die Kristallstruktur von [Cp″Mo(Co)2]2 (Cp″ = n5-C5H3t-Bu2-1,3)

Mono- and Di-t-Butylcyclopentadienyl Carbonyl Complexes of Iron and Molybdenum — Crystal Structure of [Cp″Mo(CO)₂]₂ (Cp″ = n⁵-C₅H₃-t-Bu₂-1,3) Cothermolysis of M(CO)_m (M = Fe, m = 5; M = Mo, m = 6) with t-Bu-substituted cyclopentadienyls constitutes a simple synthesis of complexes of the type [Cp*M(CO)_n]₂ (CP* = n⁵-C₅H₃ (t-Bu), R, R = H, t-Bu; M = Fe, Mo; n = 2, 3). Each synthesis has an optimal temperature. The yield of Fe complexes decreases at temperatures above 130°C because of decomposition of the product. Optimal yields of [Cp*Mo(CO)₃]₂ are obtained at 130–140°C, whereas at 160°C complexes of the type [Cp*Mo(CO)₂]₂ with formal Mo? Mo triple bonds are obtained. The structure of the complexes is discussed on the basis of ¹H-, ¹³C-NMR, IR, and mass spectrometry. The structure of [Cp″Mo(CO)₂]₂ (Cp″ = n⁵-C₅H₃t-Bu₂-1,3) was determined by X-ray crystallography at ?95°C. It crystallises in the space group Pbca, with cell constants a = 1808.6(6), b = 1308.5(4), c = 2507.9(9) pm, Z = 8, R = 0.031 for 3794 reflections. The Mo? Mo bond length of 253.3 pm is very long for a formal triple bond. The Cp″? Mo? Mo? Cp″ axis is non-linear.     

[(Mes3Sn)2MoO4], ein monomeres Triorganozinnmolybdat

[(Mes₃Sn)₂MoO₄], a Monomeric Triorganotin Molybdate Mes₃SnBr (Mes = 1, 3, 5‐trimethylphenyl) reacts with (NBu₄)₂[Mo₆O₁₉] in the presence of (NBu₄)OH (in CH₃CN as solvent) to form [(Mes₃Sn)₂MoO₄]. Alternatively the title compound can be obtained from the reaction of [MoO₂(acac)₂] (acac = 2, 4‐pentadionate) with Mes₃SnOH in isopropanol. [(Mes₃Sn)₂MoO₄] forms monoclinic crystals, space group C2/c, with a = 2271.6(3) pm, b = 825.2(1) pm, c = 2739.9(5) pm, β = 90.96(2)°. The crystal structure consists of isolated molecules in which a tetrahedral MoO₄ unit is connected to two terminal Mes₃Sn groups. The Mo‐O distances range from 169.6(4) to 181.1(3) pm and the Sn‐O distance is 204.8(3) pm.