Intriguing E…E' bonding in [Nap(EPh)(E'Ph)]•+ (E,E'=O,S, Se,Te)

The nature of E···E' bonding in homonuclear (E = E') and heteronuclear (E ≠ E') [Nap(EPh)(E'Ph)]^?+ (E, E' = O, S, Se, and Te) radical cations has been investigated by quantum chemistry and the topological analysis of electron density. The calculation results show that the E···E' bonding in the title compounds occurs through attractive interactions; O···E' (E'=O, S, Se, and Te) bonding are electrostatic interactions, and the others have a partial covalent character. The nature of E···E' bonding varies periodically, with the changes of E' atoms going from the lighter to the heavier (O, S, Se, and Te). Both in homonuclear and heteronuclear [Nap(EPh)(E'Ph)]^?+, for the same E atom, a heavier E' atom means stronger E···E/E' bonding, a more covalent character of the E···E' bond, and more spin electron density transfers from benzene rings to the E···E' group. © 2016 Wiley Periodicals, Inc.     

Octahedral Tin(IV) Complexes of the Chalcogen‐Centered Ligands [EC(PPh2S)2]2– (E = S,Se)

The metathetical reactions between SnBr₄ and Li₂[E'C(PPh₂E)₂] in toluene produce the homoleptic tin(IV) complexes Sn[E′C(PPh₂E)₂]₂ [E = E′ = S ( 1b ); E = S, E′ = Se ( 1c )], which were isolated as red crystals and structurally characterized by X‐ray crystallography. The metrical parameters of these octahedral complexes are compared with those of the all‐selenium analog Sn[E′C(PPh₂E)₂]₂ (E = E′ = Se, 1a ), which was prepared previously by a different route.     

Zur Darstellung phosphido‐chalkogenido‐verbrückter Dirheniumkomplexe vom Typ Re2(μ‐PCy2)(μ‐ER)(CO)8 (E = S,Se, Te; R = org. Rest)

Synthesis of Phosphido Chalcogenido Bridged Dirhenium Complexes of the Type Re₂(μ‐PCy₂)(μ‐ER)(CO)₈ (E = S, Se, Te; R = org. Residue) The reaction of Re₂(μ‐Br)(μ‐PCy₂)(CO)₈ with nucleophiles MER (M = Na, Li; E = S, Se, Te; R = org. residue) gives via substitution of the bromido bridge phosphido chalcogenido bridged dirhenium complexes of the general formula Re₂(μ‐PCy₂)(μ‐ER)(CO)₈. The new compounds were characterized by IR, ¹H and ¹³C NMR spectroscopic data and by elemental analyses. In addition the molecular structures for E = S, Se, Te and R = Ph as well as for E = S and R = H, n‐Bu, 2‐pyridyl have been established by single crystal X‐ray analysis. ¹³C NMR spectra of Re₂(μ‐PCy₂)(μ‐EPh)(CO)₈ (E = S, Se, Te) prove that the sulfur and selenium compounds are at room temperature dynamic molecules due to inversion of the pyramidal chalcogenido bridge. The tellurium compound, however, is rigid on the time scale of ¹³C NMR spectroscopy. Eventually the reactivity of the SH function of the novel complex Re₂(μ‐PCy₂)(μ‐SH)(CO)₈ was investigated by reaction with Re₂(CO)₈(MeCN)₂. In toluene at 90 °C the novel spirocyclic complex Re₂(μ‐PCy₂)(CO)₈(μ₄‐S)Re₂(μ‐H)(CO)₈ was formed by SH oxidative addition.     

Stable ‐ESiMe3 Complexes of CuI and AgI (E=S,Se) with NHCs: Synthons in Ternary Nanocluster Assembly

As a part of efforts to prepare new “metallachalcogenolate” precursors and develop their chemistry for the formation of ternary mixed‐metal chalcogenide nanoclusters, two sets of thermally stable, N‐heterocyclic carbene metal–chalcogenolate complexes of the general formula [(IPr)Ag?ESiMe₃] (IPr=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene; E=S, 1 ; Se, 2 ) and [(iPr₂‐bimy)Cu?ESiMe₃]₂ (iPr₂‐bimy=1,3‐diisopropylbenzimidazolin‐2‐ylidene; E=S, 4 ; Se, 5 ) are reported. These are prepared from the reaction between the corresponding carbene metal acetate, [(IPr)AgOAc] and [(iPr‐bimy)CuOAc] respectively, and E(SiMe₃)₂ at low temperature. The reaction of [(IPr)Ag?ESiMe₃] 1 with mercury(II) acetate affords the heterometallic complex [{(IPr)AgS}₂Hg] 3 containing two (IPr)Ag?S^? fragments bonded to a central Hg^II, representing a mixed mercury–silver sulfide complex. The reaction of [(iPr₂‐bimy)Cu‐SSiMe₃]₂, which contains a smaller N‐heterocyclic‐carbene, with mercuric(II) acetate affords the high nuclearity cluster, [(iPr₂‐bimy)₆Cu₁₀S₈Hg₃] 6 . The new N‐heterocyclic carbene metal–chalcogenolate complexes 1 , 2 , 4 , 5 and the ternary mixed‐metal chalcogenolate complex 3 and cluster 6 have been characterized by multinuclear NMR spectroscopy (¹H and ¹³C), elemental analysis and single‐crystal X‐ray diffraction.     

Zinkselenid- und Zinktelluridcluster mit Phenylselenolat- und Phenyltellurolatliganden. Die Kristallstrukturen von [NEt4]2[Zn4Cl4(SePh)6], [NEt4]2[Zn8Cl4Se(SePh)12], [Zn8Se(SePh)14(PnPr3)2], [HPnPr2R]2[Zn8Cl4Te(TePh)12] (R = nPr,Ph) und [Zn10Te4(TePh)12(PR3)2] (R = nPr,Ph)

Zincselenide- and Zinctellurideclusters with Phenylselenolate- and Phenyltellurolateligands. The Crystal Structures of [NEt₄]₂[Zn₄Cl₄(SePh)₆], [NEt₄]₂[Zn₈Cl₄Se(SePh)₁₂], [Zn₈Se(SePh)₁₄(PⁿPr₃)₂], [HPⁿPr₂R]₂[Zn₈Cl₄Te(TePh)₁₂] (R = ⁿPr, Ph), and [Zn₁₀Te₄(TePh)₁₂(PR₃)₂] (R = ⁿPr, Ph) In the prescence of NEt₄Cl ZnCl₂ reacts with PhSeSiMe₃ or a mixture of PhSeSiMe₃/Se(SiMe₃)₂ to form the ionic complexes [NEt₄]₂[Zn₄Cl₄(SePh)₆] 1 or [NEt₄]₂[Zn₈Cl₄Se(SePh)₁₂] 2 respectively. The use of PⁿPr₃ instead of the quarternary ammonia salt leads in toluene to the formation of crystalline [Zn₈Se(SePh)₁₄(PⁿPr₃)₂] 3 . Reactions of ZnCl₂ with PhTeSiMe₃ and tertiary phosphines result in acetone in crystallisation of the ionic clusters [HPⁿPr₂R]₂[Zn₈Cl₄Te(TePh)₁₂] (R = ⁿPr 4 , Ph 5 ) and in THF of the uncharged [Zn₁₀Te₄(TePh)₁₂(PR₃)₂] (R = ⁿPr 6 , Ph 7 ). The structures of 1–7 were obtained by X-ray single crystal structure. ( 1 : space group P2₁/n (No. 14), Z = 4, a = 1212,4(2) pm, b = 3726,1(8) pm, c = 1379,4(3) pm β = 99,83(3)°; 2 space group P2₁/c (Nr. 14), Z = 4, a = 3848,6(8) pm, b = 1784,9(4) pm, c = 3432,0(7) pm, β = 97,78(3)°; 3 : space group Pnn2 (No. 34), Z = 2, a = 2027,8(4) pm, b = 2162,3(4) pm, c = 1668,5(3) pm; 4 : space group P2₁/c (No. 14), Z = 4, a = 1899,8(4) pm, b = 2227,0(5) pm, c = 2939,0(6) pm, β = 101,35(3)°; 5 : space group space group P2₁/n (No. 14), Z = 4, a = 2231,0(5) pm, b = 1919,9(4) pm, c = 3139,5(6) pm, β = 109,97(4)°; 6 : space group I4₁/a (No. 88), Z = 4, a = b = 2566,0(4) pm, c = 2130,1(4) pm; 7 : space group P1¯ (No. 2), Z = 2, a = 2068,4(4) pm, b = 2187,8(4) pm, c = 2351,5(5) pm, α = 70,36°, β = 84,62°, γ( = 63,63°)     

Designed Construction of Mixed-Metal,Mixed Chalcogenide Clusters

Room temperature reactions between Fe₂(CO)₆(μ-EE'), (E and E' = S, Se or Te) and M(CO)₅(thf), M = Cr, Mo or W yield three types of clusters, the formation of each type clearly dependent on the nature of E and E' present in Fe₂(CO)₆(μ-EE') and on the nature of M in M(CO)₅(thf). While the Mo and W adducts are based on square pyramidal heavy atom cores, the Cr adduct has an unusual structure and can be considered as an inorganic analog of quadricyclane.     

Integrity and Structural Characteristics of the M6E8 (E=S, Se, Te) Cluster Core: Syntheses and Structures of [Co6S8(PR3)6] n+ (R=Me2Ph, n=1; R=OMe, n=0)

Two new members of the hexanuclear series [Co₆S₈(PR₃)₆] ⁿ⁺, complexes [Co₆S₈(PMe₂Ph)₆](ClO₄) (1) and [Co₆S₈P(OMe)_{3 6}] (2), have been synthesizes and characterized by X-ray diffraction analyses. Their formation process was postulated to go through trinuclear ₃--S bridged moieties. The structural characteristics of the M₆E₈P₆ skeleton of a whole series of [M₆E₈(PR₃)₆] ⁿ⁺ (M=Co, Cr, Fe, Mo; E=S, Se, Te) complexes are presented in terms of atomic distances and core volumes.     

Trigonal‐Bipyramidal and Square‐Pyramidal Chromium?Manganese Chalcogenide Clusters, [E2CrMn2(CO)n]2− (E=S,Se, Te; n=9, 10): Synthesis,Electrochemistry, UV/Vis Absorption,and Computational Studies

The reactions of E powder (E=S, Se) with a mixture of Cr(CO)₆ and Mn₂(CO)₁₀ in concentrated solutions of KOH/MeOH produced two new mixed Cr? Mn? carbonyl clusters, [E₂CrMn₂(CO)₉]^2? (E=S, 1 ; Se, 2 ). Clusters 1 and 2 were isostructural with one another and each displayed a trigonal‐bipyramidal structure, with the CrMn₂ triangle axially capped by two μ₃‐E atoms. The analogous telluride cluster, [Te₂CrMn₂(CO)₉]^2? ( 3 ), was obtained from the ring‐closure of Te₂Mn₂ ring complex [Te₂Mn₂Cr₂(CO)₁₈]^2? ( 4 ). Upon bubbling with CO, clusters 2 and 3 were readily converted into square‐pyramidal clusters, [E₂CrMn₂(CO)₁₀]^2? (E=Se, 5 ; Te, 6 ), accompanied with the cleavage of one Cr? Mn bond. According to SQUID analysis, cluster 6 was paramagnetic, with S=1 at room temperature; however, the Se analogue ( 5 ) was spectroscopically proposed to be diamagnetic, as verified by TD‐DFT calculations. Cluster 6 could be further carbonylated, with cleavage of the Mn? Mn bond to produce a new arachno‐cluster, [Te₂CrMn₂(CO)₁₁]^2? ( 7 ). The formation and structural isomers, as well as electrochemistry and UV/Vis absorption, of these clusters were also elucidated by DFT calculations.     

Darstellung,Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalyse von cis‐(n‐Bu4N)2[Pt(ECN)2(ox)2], E = S,Se

Synthesis, Crystal Structure, Vibrational Spectra, and Normal Coordinate Analysis of cis‐(n‐Bu₄N)₂[Pt(ECN)₂(ox)₂], E = S, Se By exposure of trans‐(n‐Bu₄N)₂[Pt(ECN)₂(ox)₂], E = S and Se, in dichloromethane cis‐(n‐Bu₄N)₂[Pt(SCN)₂(ox)₂] ( 1 ) and cis‐(n‐Bu₄N)₂[Pt(SeCN)₂(ox)₂] ( 2 ) are formed. The crystal structure of 1 (triclinic, space group P1¯, a = 10.789(1), b = 11.906(1), c = 18.580(1)Å, α = 85.619(10), β = 85.272(10), γ = 75.173(10)°, Z = 2) reveals, that the compound crystallizes as a racemic mixture with C₂ point symmetrical complex anions. The bond lengths in both S′‐Pt‐O^˙ axes are Pt‐S′ = 2.321 and Pt‐O^˙ = 2.048 and in the O‐Pt‐O axis Pt‐O = 2.007Å. The oxalato ligands are nearly plane with O‐C‐C‐O torsion angles of 1.4 — 3.9°. The via S′ bound linear thiocyanate groups are coordinated with Pt‐S′‐C angles of 102.6°. In the vibrational spectra the PtE′ stretching vibrations are observed at 327 — 330 ( 1 ) and 217 — 231 cm^—1 ( 2 ). The PtO^˙ and PtO stretching vibrations are coupled with internal vibrations of the oxalato ligands and appear in the range of 400 — 800 cm^—1. Based on the molecular parameters of the X‐ray determination ( 1 ) and estimated data ( 2 ) the IR and Raman spectra are assigned by normal coordinate analysis. The valence force constants are f_d(PtS′) = 2.08, f_d(PtSe′) = 1.78, f_d(PtO^˙) = 2.45 ( 1 ) and 2.27 ( 2 ) and f_d(PtO) = 2.65 ( 1 ) and 2.60 mdyn/Å ( 2 ). Taking into account increments of the trans influence a good agreement between observed and calculated frequencies is achieved. The NMR shifts are δ(¹⁹⁵Pt) = 4925.9 ( 1 ), 4783.0 ( 2 ) and δ(⁷⁷Se) = 161.7 ppm with the coupling constant ¹J(SePt) = 366.2 Hz.     

Synthesen und Kristallstrukturen der chalkogenidoverbrückten Nickelclusterverbindungen [Ni5Se4Cl2(PPhEt2)6], [Ni12Se12(PnPr3)6] und [Ni18S18(PiPr3)6]

Syntheses and Crystal Structures of Chalcogenido‐bridged Nickel Cluster Compounds [Ni₅Se₄Cl₂(PPhEt₂)₆], [Ni₁₂Se₁₂(PⁿPr₃)₆], and [Ni₁₈S₁₈(PⁱPr₃)₆] The reaction of (R)ESiMe₃ (R = SiMe₃, Mes = C₉H₁₁; E = S, Se) with [NiCl₂(PPhEt₂)₂] and [NiCl₂(PR₃)₂] (R = ⁿPr, ⁱPr) gives new chalcogenido‐bridged nickel cluster compounds [Ni₅Se₄Cl₂(PPhEt₂)₆]·2THF ( 1 ), [Ni₁₂Se₁₂(PⁿPr₃)₆]·2THF ( 2 ), and [Ni₁₈S₁₈(PⁱPr₃)₆]·2THF ( 3 ). The structures of these compounds were determined by single crystal X‐ray structural analyses.     

Molybdenum(0) and Tungsten(0) Complexes with P,S and P,Se Monooxidized Bis(phosphanyl)amine Ligands

Reactions of monooxidized thioyl and selenoyl bis(phosphanyl)amine ligands C₁₀H₇‐1‐N(P(E)Ph₂)(PPh₂) [E = S ( 1 ), Se ( 2 )] with Mo(CO)₄(pip)₂ and W(CO)₄(cod) afforded the complexes [M(CO)₄{ 1 ‐κ²P,S}] [M = Mo ( 3 ), W ( 4 )] and [M(CO)₄{ 2 ‐κ²P,Se}] [M = Mo ( 5 ), W ( 6 )]. Complexes 3 – 6 were characterized by multinuclear NMR (¹H, ¹³C, ³¹P, and ⁷⁷Se NMR) and IR spectroscopy. Crystal‐structure determinations were carried out on 3 , 5 , and 6 , which represent the first examples of structurally characterized complexes of such ligands with group‐6 metal carbonyls.     

Oxidative Addition vs. Ligand-Exchange: Fe(II)-Mixed-Phenylchalcogenolate Complexes fac-[PPN][Fe(CO)3(TePh)n(SePh)3-N] (n = 1, 2)

Diphenyldichalcogenides (PhE)₂ (E = Te, Se) react with Fe(0)-phenylchalcogenolate [PPN] [PhEFe(CO)₄] to yield the products of oxidative addition, Fe(II)-mixed-phenylchalcogenolate fac- [PPN][Fe(CO)₃(TePh)_n(ScPh)_3-n] (n = 1, 2). Reactions of [PPN][REFe(CO)₄] (E=Se, R=Me; E=S, R=Et) and diphenyldichalcogenides yielded ligand-exchange products [PPN][PhEFe(CO)₄] (E=Te, Se, S). The compounds [Fe(CO)₃(TePh)(ScPh)₂]^? (l) and [Fe(CO)₃(TePh)₂ (2) crystallize in the isomorphous monoclinic space group C_2/e, with a = 32.035(8), b = 11.708(6), c = 28.909(6) Å, Z = 8, R = 0.048, and R_w = 0.044 (1); with a = 32.089(5), b= 11.745(2), c = 28.990(8) Å, Z = 8, R = 0.048, and R_w = 0.048 (2). The complexes 1 and 2 crystallize as discrete cations of PPN⁺ and anions of [Fe(CO)₃(TcPh)_u(ScPh)_3-n] (n=1, 2), and one half solvent molecule THF. The geometry around Fe(II) is a distorted octahedron with three carbonyl groups and three phenylchalcogenolate ligands occupying facial positions.     

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.     

Chalkogen‐Derivate der Halbsandwich‐Wolfram(V)‐Komplexe Cp*WCl4 und Cp*WCl4(PMe3). Röntgen‐Kristallstrukturanalysen von anti‐[Cp*W(Se)(μ‐Se)]2 und Cp*W(S)2(OMe)

Chalcogen Derivatives of the Halfsandwich Tungsten(V) Complexes Cp*WCl₄ and Cp*WCl₄(PMe₃). X‐Ray Crystal Structure Analyses of anti ‐[Cp*W(Se)(μ‐Se)]₂ and Cp*W(S)₂(OMe) The chalcogenation of Cp*WCl₄ ( 1 ) by E(SiMe₃)₂ (E = S, Se) and Te(SiMe₂^tBu)₂ in chloroform solution leads to dimeric products of the type anti‐[Cp*W(E)(μ‐E)]₂ (E = S ( 3 a ), Se ( 3 b ) and Te ( 3 c )). An X‐ray structure determination of 3 b indicates a centrosymmetric molecule containing a planar W(μ‐Se)₂W ring, the W–W distance (297.9(1) pm) corresponds to a single bond. In the presence of air the two terminal chalcogenido ligands (E) in 3 a – c are stepwise replaced by oxido ligands (O) to give [Cp*W(O)(μ‐E)]₂ (E = S ( 5 a ), Se ( 5 b ) and Te ( 5 c )) in quantitative yields. The reaction of Cp*WCl₄ with H₂S or ammonium polysulfide, (NH₄)₂S_x (x ∼ 10), leads to Cp*W(S)₂Cl ( 6 a ); the corresponding methoxy derivative, Cp*W(S)₂OCH₃ ( 9 a ), has been characterized by an X‐ray structure analysis. On the other hand, the reaction of Cp*WCl₄(PMe₃) ( 2 ) with sodium tetrasulfide, Na₂S₄, in dimethylformamide solution gives a mixture of mononuclear Cp*W(S)(S₂)Cl ( 8 a ), dinuclear [Cp*W(S)(μ‐S)]₂ ( 3 a ) and a trinuclear side‐product of composition Cp*₂W₃S₇ ( 13 a ). Terminal sulfido ligands are replaced by terminal oxido ligands in solution in the presence of oxygen. Thus, 6 a is stepwise converted into Cp*W(O)(S)Cl ( 10 a ) and CpW(O)₂Cl ( 12 a ), whereas 8 a gives Cp*W(O)(S₂)Cl ( 11 a ) and 13 a leads to Cp*₂W₃(O)S₆ ( 14 a ). The disulfido complexes 8 a and 11 a are desulfurized by triphenylphosphane to give 6 a and 10 a . The new complexes have been characterized by their IR and NMR spectra and by mass spectrometry.     

Synthese gemischt chalkogenido‐verbrückter Dirheniumkomplexe vom Typ Re2(μ‐ER)(μ‐E′R′)(CO)8 (E,E′ = S,Se, Te; R,R′ = org. Rest)

Synthesis of Mixed Chalcogenido‐Bridged Dirhenium Complexes of the Type Re₂(μ‐ER)(μ‐E′R′)(CO)₈ (E, E′ = S, Se, Te; R, R′ = org. Residue) Hydrido sulfido bridged complexes Re₂(μ‐H)(μ‐SR)(CO)₈ (R = Ph, naph, Cy) react with the base DBU to give the salts [DBUH][Re₂(μ‐SR)(CO)₈]. Upon addition of electrophiles R′E′Br (E′R = SPh, SePh, TePh) to the in situ prepared salts mixed chalcogenido bridged complexes Re₂(μ‐SR)(μ‐E′R′)(CO)₈ were formed. The structures of the new compounds Re₂(μ‐SCy)(μ‐SePh)(CO)₈ and Re₂(μ‐Snaph)(μ‐TePh)(CO)₈ were determined by single crystal X‐ray analyses. For the preparation of analogous selenido tellurido bridged complexes Re₂(μ‐SePh)(μ‐TeR)(CO)₈ the novel hydrido selenido bridged complex Re₂(μ‐H)(μ‐SePh)(CO)₈ was prepared from Re₂(CO)₈(NCMe)₂ and PhSeH. Its structure was determined by single crystal X‐ray analysis. Subsequent deprotonation with DBU gave in situ [DBUH][Re₂(μ‐SePh)(CO)₈] which upon addition of RTeBr (R = Ph, Buⁿ, Bu^t) formed the desired complexes Re₂(μ‐SePh)(μ‐TeR)(CO)₈. The reaction with Bu^tTeBr also yielded the novel spirocyclic complex (μ₄‐Te){Re₂(μ‐SePh)(CO)₈}₂ in low amounts. It was identified by single crystal X‐ray analysis. Re₂(μ‐SePh)(μ‐TeBu^t)(CO)₈ is oxidised in chloroform in the presence of air to give the novel complex (μ‐Te–Te‐μ){Re₂(μ‐SePh)(CO)₈}₂. All mixed chalcogenido bridged dirhenium complexes were proved to be dynamic in solution by ¹³C NMR spectroscopy. The dynamic behaviour is based on the fast and permanent inversion of the sulfido and selenido bridges. The tellurido bridges are rigid on the time scale of ¹³C NMR spectroscopy.     

Verbindungen des Typs (F3C)2EE′R mit Pseudohalogen-Charakter (E = P,As; E′ = S,Se, Te)

Perfluoromethyl Element Ligands. XLI. [1] Compounds of the Type (F₃C)₂EE′R with Pseudohalide Character (E = P, As; E′ = S, Se, Te) Perfluoromethyl phosphorus and -arsenic compounds of the type (F₃C)₂EE′R (E = P, As; E′ = S, Se, Te; R = organic group) are prepared either by dismutation (metathesis) of E₂(CF₃)₄ with (RE′)₂ or by reaction of the iodine compounds (F₃C)₂EI with mercury(II) organosulfanides Hg(SR)₂ and characterized by spectroscopic (¹H, ¹⁹F, ³¹P-NMR; IR; MS) as well as analytical investigations (C, H).     

Fixation and Release of Intact E4 Tetrahedra (E=P,As)

By the reaction of [NacnacCuCH₃CN] with white phosphorus (P₄) and yellow arsenic (As₄), the stabilization and enclosure of the intact E₄ tetrahedra are realized and the disubstituted complexes [(NacnacCu)₂(μ,η^2:2‐E₄)] ( 1 a : E=P, 1 b : E=As) are formed. The mono‐substituted complex [NacnacCu(η²‐P₄)] ( 2 ), was detected by the exchange reaction of 1 a with P₄ and was only isolated using low‐temperature work‐up. All products were comprehensively spectroscopically and crystallographically characterized. The bonding situation in the products as intact E₄ units (E=P, As) was confirmed by theory and was experimentally proven by the pyridine promoted release of the bridging E₄ tetrahedra in 1 .     

Komplexe mit Antimon‐Liganden: [tBu2(Cl)SbW(CO)5], [tBu2(OH)SbW(CO)5], O[SbPh2W(CO)5]2, E[SbMe2W(CO)5]2 (E = Se,Te), cis‐[(Me2SbSeSbMe2)2Cr(CO)4]

Complexes Containing Antimony Ligands: [^tBu₂(Cl)SbW(CO)₅], [^tBu₂(OH)SbW(CO)₅], O[SbPh₂W(CO)₅]₂, E[SbMe₂W(CO)₅]₂ (E = Se, Te), cis‐[(Me₂SbSeSbMe₂)₂Cr(CO)₄] Syntheses of [^tBu₂(Cl)SbW(CO)₅] ( 1 ), [^tBu₂(OH)SbW(CO)₅] ( 2 ), O[SbPh₂W(CO)₅]₂ ( 3 ), Se[SbMe₂W(CO)₅]₂ ( 4 ), cis‐[(Me₂SbSeSbMe₂)₂Cr(CO)₄] ( 5 ) Te[SbMe₂W(CO)₅]₂ ( 6 ) and crystal structures of 1 – 5 are reported.     

Synthesis, characterisation and redox behaviour of isocyanide incorporated, chalcogen stabilised mixed-metal clusters

Room temperature reaction of a benzene solution of [Cp₂Mo₂Fe₂(CO)₇(μ₃-E)(μ₃-E^′)] (EE^′=Se₂ (1), STe (2), SeTe (3)) with PrⁱNC or Bu^tNC resulted in the formation of iron bonded isocyanide clusters [Cp₂Mo₂Fe₂(RNC)(CO)₆ (μ₃-E)(μ₃-E^′)], [E=E^′=Se, R=Prⁱ (5) or Bu^t (9); E=S, E^′=Te, R=Prⁱ (6a, 6b) or R=Bu^t (10a, 10b); E=Se, E^′=Te, R=Prⁱ (7a, 7b) or R=Bu^t (11a, 11b)] and molybdenum bonded isocyanide clusters [Cp₂(RNC)Mo₂Fe₂(CO)₆(μ₃-E)(μ₃-E^′)], [E=E^′=Se, R=Prⁱ(13) or Bu^t (17); E=S, E^′=Te, R=Prⁱ (14) or R=Bu^t, (18); E=Se, E^′=Te, R=Prⁱ (15) or R=Bu^t (19)]. Two isomers (a and b) were detected by ¹H NMR spectroscopy for the mixed-chalcogen clusters 6, 7, 10 and 11, where the isocyanide group is bonded to an iron atom. Thermolytic reaction conditions were necessary for the reaction of [(η⁵-C₅H₅)₂Mo₂Fe₂(CO)₇(μ₃-Te)₂] (4) with Prⁱ NC or Bu^t NC to give [Cp₂Mo₂Fe₂(RNC)(CO)₆(μ₃-Te)₂] (R=Prⁱ (8) or R=Bu^t, (12)) and [Cp₂(RNC)Mo₂Fe₂(CO)₆(μ₃-Te)₂] (R=Prⁱ (8)). Compounds 5-19 have been characterised by IR and ¹H and ¹³C NMR spectroscopy. The Se- and Te-bridged compounds have been further characterised by ⁷⁷Se and ¹²⁵Te NMR spectroscopy. The structures of compounds 12 and 14 were determined by single crystal X-ray diffraction methods. Redox properties of the mixed-metal clusters, 2, 6, 8, 12 and 14 have been studied by cyclic voltammetry in the potential range ±2.5 V at 298 K, using a platinum working electrode.     

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.