Electron impact and ammonia chemical ionization mass spectra of n-azabicyclo[m.2.0]alkan-(n + 1)-ones (m = 3–6, n = 6–9)

Electron impact induced fragmentation of the title compounds obeys a route where the lactam moiety, OCNH, is cleaved first, with the accompanying formation of a cycloalkene ion. This can be verified by low-resolution, high-resolution, B/E and B²/E spectra as well as by collisional activation spectra of, for example, the ions m/z 82 and 67 from 7-azabicyclo[4.2.0]octan-8-one and from cyclohexene. The only, and fairly weak, fragment ions including O and N are [C₃H₃O]+, [C_kH_2k-2N]⁺ (k = 5–8) and [C₃H₆N]⁺. The ammonia chemical ionization spectra are also characteristic for all four lactams and show the same dominant ions in all cases, namely [M + 1]⁺, [M + 1 + NH₃]⁺˙ and [2 M + 1]⁺˙.     

Gitonic and distonic alkanonium dications (diprotonated alkane dications C(n)H(2n+4(2+)), n = 1-4)(1)

The structures and stabilities of gitonic and distonic alkanonium dications, i.e., diprotonated alkane dications C(n)H(2n+4)(2+) (n = 1-4), were investigated at the MP4(SDTQ)/6-311G**//MP2/6-31G** level. The global minimum energy structures (2, 4, 7, and 10) of the C(n)H(2n+4)(2+) dications are double C--H protonated alkanes to give structures with two two electron three-center (2e-3c) bonds. Two different dissociation pathways for the dications, viz deprotonation and demethylation, were also computed. Demethylation was found to be the favorable mode of dissociation.     

Über die Darstellung der N-Chlor-N-Methylammoniumsalze (CH3)nNCl4–n+MF6− (n = 1–3; M = As,Sb) und (CH3)2NCIX+MF6− (X = F,Br)

About the Preparation of N-Chloro-N-Methylammonium Salts (CH₃)_nNCl_4–n⁺MF₆^? (n = 1–3; M = As, Sb) and (CH₃)₂NClX⁺MF₆^? (X = F, Br) Simple one-step methods for the preparation of the methylated chloroammonium salts (CH₃)_nNCl_4–n⁺MF₆^? (n = 1–3; M = As, Sb) and for (CH₃)₂NClX⁺MF₆^? (X = F, Br) are reported. Their vibrational and NMR-spectroscopical data are discussed in comparison.     

Darstellung,Kristallstrukturen und Schwingungsspektren von [Pt(N3)6]2– und [Pt(N3)Cl5]2–, 195Pt‐ und 15N‐NMR‐Spektren von [Pt(N3)nCl6–n]2– und [Pt(15NN2)n(N215N)6–n]2–, n = 0–6

Synthesis, Crystal Structures, and Vibrational Spectra of [Pt(N₃)₆]^2– and [Pt(N₃)Cl₅]^2–, ¹⁹⁵Pt and ¹⁵N NMR Spectra of [Pt(N₃)_nCl_6–n]^2– and [Pt(¹⁵NN₂)_n(N₂¹⁵N)_6–n]^2–, n = 0–6 By ligand exchange of [PtCl₆]^2– with sodium azide mixed complexes of the series [Pt(N₃)_nCl_6–n]^2– and with ¹⁵N‐labelled sodium azide (Na¹⁵NN₂) mixtures of the isotopomeres [Pt(¹⁵NN₂)_n(N₂¹⁵N)_6–n]^2–, n = 0–6 and the pair [Pt(¹⁵NN₂)Cl₅]^2–/[Pt(N₂¹⁵N)Cl₅]^2– are formed. X‐ray structure determinations on single crystals of (Ph₄P)₂[Pt(N₃)₆] ( 1 ) (triclinic, space group P1, a = 10.175(1), b = 10.516(1), c = 12.380(2) Å, α = 87.822(9), β = 73.822(9), γ = 67.987(8)°, Z = 1) and (Ph₄As)₂[Pt(N₃)Cl₅] · HCON(CH₃)₂ ( 2 ) (triclinic, space group P1, a = 10.068(2), b = 11.001(2), c = 23.658(5) Å, α = 101.196(14), β = 93.977(15), γ = 101.484(13)°, Z = 2) have been performed. The bond lengths are Pt–N = 2.088 ( 1 ), 2.105 ( 2 ) and Pt–Cl = 2.318 Å ( 2 ). The approximate linear azido ligands with N^α–N^β–N^γ‐angles = 173.5–174.6° are bonded with Pt–N^α–N^β‐angles = 116.4–121.0°. In the vibrational spectra the PtCl stretching vibrations of (n‐Bu₄N)₂[Pt(N₃)Cl₅] are observed at 318–345, the PtN stretching modes of (n‐Bu₄N)₂[Pt(N₃)₆] at 401–428 and of (n‐Bu₄N)₂[Pt(N₃)Cl₅] at 408–413 cm^–1. The mixtures (n‐Bu₄N)₂[Pt(¹⁵NN₂)_n(N₂¹⁵N)_6–n], n = 0–6 and (n‐Bu₄N)₂[Pt(¹⁵NN₂)Cl₅]/(n‐Bu₄N)₂[Pt(N₂¹⁵N)Cl₅] exhibit ¹⁵N‐isotopic shifts up to 20 cm^–1. Based on the molecular parameters of the X‐ray determinations the vibrational spectra are assigned by normal coordinate analysis. The average valence force constants are f_d(PtCl) = 1.93, f_d(PtN^α) = 2.38 and f_d(N^αN^β, N^βN^γ) = 12.39 mdyn/Å. In the ¹⁹⁵Pt NMR spectrum of [Pt(N₃)_nCl_6–n]^2–, n = 0–6 downfield shifts with the increasing number of azido ligands are observed in the range 4766–5067 ppm. The ¹⁵N NMR spectrum of (n‐Bu₄N)₂[Pt(¹⁵NN₂)_n(N₂¹⁵N)_6–n], n = 0–6 exhibits by ¹⁵N–¹⁹⁵Pt coupling a pseudotriplett at –307.5 ppm. Due to the isotopomeres n = 0–5 for terminal ¹⁵N six well‐resolved signals with distances of 0.03 ppm are observed in the low field region at –201 to –199 ppm.     

DFT studies on TinC2n (n=1–6) clusters

The geometric configurations and electronic structures of the Ti_nC_2n (n=1–6) clusters were studied by using the quantum chemical ab initio density functional theory (DFT) method. Our studies showed that these Ti_nC_2n (n=1–6) could grow gradually to form cyclic clusters through the subunits TiC₂ bonding to each other by C C or Ti C bond. The result could explain the existing experimental fact. The studies might also be helpful to the knowledge of the formation mechanism of the Met‐Cars. ©1999 John Wiley & Sons, Inc. Int J Quant Chem 71: 313–318, 1999     

Darstellung gemischter Kaliumhexabromochloro-osmate(IV), K2OsBrnCl6–n (n = 1…5) und Kaliumhexabromochloro-rhenate(IV), K2ReBrnCl6–n (n = 1…5)

Preparation of Mixed Potassium Hexabromochloro Osmates(IV), K₂OsBr_nCl_6–n (n = 1…5), and Potassium Hexabromochloro Rhenates(IV), K₂ReBr_nCl_6–n (n = 1…5) Solutions of mixed hexabromochloro osmates and rhenates which were separated by ion column chromatography are extracted by tridodecylamine in ether. The potassium salts are precipitated from the extractions with potassium acetate and following further purification are characterized spectrophotometrically and by powder X-ray methods.     

Magnetic and Spectral Properties of Heterotrinuclear Acetates [Ru2Co(μ3-O)(μ-CH3CO2)6(Py)3]n+ (n = 0 or 1)

The preparation and physical properties of the new heterotrinuclear acetates, [Ru₂CO(μ₃-O)(μ-CH₃CO₂)₆(Py)₃] (Ru₂Co(II)) and [Ru₂Co(μ₃-O)(μ-CH₃CO₂)₆(Py)₃)l₃ (Ru₂Co(III), Py = pyridine), are reported. Three reversible one-electron-redox waves are observed at 1.19, 0.40, and ?1.24 V vs Ag/Ag⁺ electrode for Ru₂Co(lI) in CH₂Cl₂. The complexes of Ru₂Co(II) and Ru₂Co(III) show an intense visible absorption at 570 (? 5950 M^?1 cm^?1) and 551 nm (? 7240 M^?1 cm^?1), respectively. The magnetic susceptibilities of both complexes were also measured from 4.2 to 300 K. The resulting least-squares fit parameters for Ru₂Co(II) areJ_RuCo = ?9 cm^?1, J_RuRu = ?22 cm^?1, g_Co, = g_Ru= 2.19.     

[C(AuPH3)m]n+ (m=4-6; n=0-2)成键性质和稳定性研究

用MP2/LanL2DZ方法优化C(AuPH3)4[1a(C4v); 1b(Td)], [C(AuPH3)5]+[2a(C3h); 2b(Cs)]以及[C(AuPH3)6}]2+[3a(C2h); 3b(C2v)]的结构, 得到的几何参数与实验值相符. MP2水平下的自然键轨道(Natural bond orbitals, NBO)分析表明, Au具有d(sp)杂化性质, 其中(sp)具有s-p混合的轨道性质; 沿C-Au辐射方向形成的σ键和切向Au-Au之间的弱吸引相互作用使得整个分子稳定. 化合物1a, 2和3具有2或3个二电子三中心键, 表明该类化合物具有与传统C化学不同的电子结构和立体化学构型.     

A structural investigation of [C6H6]2+ and [C6H6]+˙ ions involved in charge exchange reactions

Mass-analysed ion kinetic energy spectra for collisional activation (CA) of [C₆H₆]⁺˙ formed via electron capture by [C₆H₆]²⁺ ions in collision with neutral benzene molecules have been compared for the C₆H₆ isomers benzene, 1,5-hexadiyne and 2,4-hexadiyne. Comparisons of fragment abundance and total CA fragment yields were also made for [C₆H₆]⁺˙ ions generated by electron ionization (EI). CA conditions of ion velocity and collision gas pressure were identical in these comparisons. In general the fragment abundance patterns for the ions formed by charge exchange were very similar to those for singly charged benzene ions generated by EI. However, significant variations in CA fragment yield (the ratio of the total CA fragment ion abundance to the abundance of the incident unfragmented ions) were observed. It is not clear from the results whether these variations reflect structurally different ions or ions of different internal energies. The CA spectra of [C₆H₆]⁺˙ ions derived from charge exchange reactions between the benzene dication and the target gases He, Ne, Ar, Kr and Xe have also been recorded and, once again, very similar fragment abundance patterns were observed along with large variations in total CA fragment yields. Charge exchange efficiency measurements are reported for reactions between the benzene dication and the targets He, Ne, Ar, Kr, Xe and C₆H₆ (benzene) and also for the doubly charged ions derived from the linear C₆H₆ isomers. In the latter case Xe and benzene targets were used. The energetics and efficiency measurements for the former reactions suggest that for targets such as He and Ne the processes probably involve excited states of the doubly charged ions. The efficiencies measured for the latter reactions were distinctly different for the three C₆H₆ isomers and may indicate a strong dependence of charge exchange cross-section on doubly charged ion structure.     

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.     

Palladium(II) and Platinum(II) Complexes with Bisphosphanes, [S2C=C(CN)2]2– and [Se2C=C(CN)2]2– as Chelating Ligands

The palladium(II) and platin(II) 1, 1‐dicyanoethylene‐2, 2‐dithiolates [(L–L)M{S₂C=C(CN)₂}] (M = Pd: L–L = dppm, dppe, dcpe, dpmb; M = Pt: dppe, dcpe, dpmb) were prepared either from[(L–L)MCl₂] and K₂[S₂C=C(CN)₂] or from [(PPh₃)₂M{S₂C=C(CN)₂}] and the bisphosphane. Moreover, [(dppe)Pt{S₂C=C(CN)₂}]was obtained from [(1, 5‐C₈H₁₂)Pt{S₂C=C(CN)₂}] and dppeby ligand exchange. The 1, 1‐dicyanoethylene‐2, 2‐diselenolates[(dppe)M{Se₂C=C(CN)₂}] (M = Pd, Pt) were prepared from[(dppe)MCl₂] and K₂[Se₂C=C(CN)₂]. The oxidation potentials of the square‐planar palladium and platinum complexes were determined by cyclic voltammetry. The reaction of [(dcpe)Pd(S₂C=O)] with TCNE led to a ligand fragment exchange and gave the 1, 1‐dicyanoethylene‐2, 2‐dithiolate [(dcpe)Pd{S₂C=C(CN)₂}] in good yield.     

195Pt-NMR-spektroskopischer Nachweis gemischter Hexahalogenodiplatinate(II), [Pt2ClnBr6 − n]2−, n = 0 – 6

¹⁹⁵Pt NMR Spectroscopic Evidence of Mixed Hexahalogenodiplatinates(II), [Pt₂Cl_nBr_{6 ? n}]^2?, n = 0 – 6 The complete system of the mixed complex ions [¹⁹⁵Pt₂Cl_nBr_{6 – n}]^2?, n = 0 – 6, is formed by stirring a suspension of the tetrabutylammonium salt(TBA)₂[¹⁹⁵PtCl₄] in an aqueous solution of KBr at 80°C. The mixture recrystallized from acetone/diethyl ether contains the 24 possible species, 12 with two equivalent ¹⁹⁵Pt atoms resulting in 12 singlets and 12 with inequivalent ¹⁹⁵Pt atoms resulting in 24 dublets. The expected 60 signals are really observed in the high resolution 1D-¹⁹⁵Pt-nmr spectrum. Using characteristic increments of chemical shifts, differentiating ²J(¹⁹⁵Pt ? ¹⁹⁵Pt) coupling constants and a 2D-¹⁹⁵Pt/¹⁹⁵Pt-COSY spectrum the complete and unambiguous assignment of all resonances is achieved. The presence of all components including the geometric isomers and their distribution derived from measured intensities reveal the statistical formation.     

Insertion Reactions of [ReH(CO)5–n(PMe3)n] Complexes (n = 2–4) with aldehydes,CO2, and activated acetylenes

The complexes of the type [ReH(CO)_5–n(PMe₃)_n] (n = 4, 3) were reacted with aldehydes, CO₂, and RC?CCOOMe (R = H, Me) to establish a phosphine-substitutional effect on the reactivity of the Re–H bond. In the series 1–3 , benzaldehyde showed conversion with only 3 to afford a (benzyloxy)carbonyltetrakis(trimethylphosphine)rhenium complex 4 . Pyridine-2-carbaldehyde allowed reaction with all hydrides 1–3 . With 1 and 2 , the same dicarbonyl[(pyridin-2-yl)methoxy-O, N]bis(trimethylphosphine)rhenium 5b was formed with the intermediacy of a [(pyridin-2-yl)methoxy-O]-ligated species and extrusion of CO or PMe₃, respectively. The analogous conversion of 3 afforded the carbonyl[(pyridin-2-yl)methoxy-O,N]tris(trimethylphosphine)rhenium ( 1 ) 7b . While 1 did not react with CO₂, 2 and 3 yielded under relatively mild conditions the formato-ligated [Re(HCO₂)(CO)(L)(PMe₃)₃] species ( 8 (L = CO) and 9 (L = PMe₃)). Methyl propiolate and methyl butynoate were transformed, in the presence of 1 , to [Re{C(CO₂Me)?CHR}(CO)₃(PMe₃)₂] systems ( 10a (R = H), and 10b (R = Me)), with prevailing α-metallation and trans-insertion stereochemistry. Similarly, HC≡CCO₂Me afforded with 2 and 3 , the α-metallation products [Re{C(CO₂Me)?CH₂}(CO)(L)(PMe₃)₃] 11 (L = CO) and 12 (L = PMe₃). The methyl butyonate insertion into 2 resulted in formation of a mixture of the (Z)- and (E)-isomers of [Re{C(CO₂Me)?CHMe} (CO)₂(PMe₃)₃] ( 13a , b ). In the case of the conversion of 3 with MeC?CCO₂Me, a Re–H cis-addition product [Re{(E)-C(CO₂Me)?CHMe}(CO)(PMe₃)₄] ( 14 ) was selectively obtained. Complex 11 was characterized by an X-ray crystal-structure analysis.     

Triphenylphosphan-Nickel(0)-Komplexe mit Isocyanid-Liganden — [(RNC)nNi(PPh3)4–n] (n = 1–3)

Triphenylphosphane Nickel(0) Complexes with Isocyanide Ligands — [(RNC)_nNi(PPh₃)_4–n] (n = 1–3) Synthesis and properties of the isocyanide triphenylphosphane nickel(0) complexes [(RNC)Ni(PPh₃)₃], [(RNC)₂Ni(PPh₃)₂] and [(RNC)₃Ni(PPh₃)] (R = ^tBu, Cy, PhCH₂, p-TosCH₂) are described. I.r. and ³¹P n.m.r. spectra were recorded and the X-ray crystal structure of [(PhCH₂NC)₂Ni(PPh₃)₂] was determined.     

Alternativ-Liganden. XXX [1] Neue Tripod-Liganden XM' (OCH2PMe2)n(CH2CH2PMe2)3−n (M' = Si; Ge; n = 0–3) für Käfigstrukturen

Alternative Ligands. XXX Novel Tripod Ligands XM' (OCH₂PMe₂)_n(CH₂CH₂PMe₂)_3?n (M' = Si, Ge; n = 0–3) for Cage Structures Attempts to prepare new tripod ligands XSi(OCH₂PMe₂)₃ [X = CF₃ ( 15 ), C₆F₅ ( 16 ), NMe₂ ( 17 ), Cl ( 18 ), F ( 19 ), H ( 20 ), OEt ( 21 ), OMe ( 22 )] prove to be unsuccessful in spite of using different pathways, because the groups X undergo following reactions giving insoluble solids (polyadducts) or form inseparable mixtures, e. g. (RO)_nSi(OCH₂PMe₂)_4?n (R = Me, Et). In many cases Si(OCH₂PMe₂)₄ ( 13 ) can be isolated from the reaction mixture. The syntheses of the ligands XSi(CH₂CH₂PMe₂)₃ [X = NMe₂ ( 6 ), Cl ( 7 ), F ( 8 ), OMe ( 9 ), Vi ( 12 )], Si(OCH₂PMe₂)₄ ( 13 ) und Me₃GeOCH₂PMe₂ ( 14 ) are successful. The compounds MeSi(OCH₂PMe₂)₂CH₂CH₂NMe₂ ( 10 ) and MeSi(OCH₂PMe₂)₂CH₂CH₂P(CF₃)₂ ( 11 ) with different donor groups are obtained in good yields. The preparative program includes the synthesis of the known representatives MeSi(OCH₂PMe₃)₃ ( 1 ), MeSi(OCH₂PMe₂)₂CH₂CH₂PMe₂ ( 2 ), MeSi(OCH₂PMe₂)(CH₂CH₂PMe₂)₂ ( 3 ), MeSi(CH₂CH₂PMe₂)₃ ( 4 ) and MeGe(OCH₂PMe₂)₃ ( 5 ). Important preparative steps are the substitution of M'Cl (M' = Si, Ge) by Me₂PCH₂O groups and the photochemically induced or base catalyzed addition of HNMe₂, HPMe₂ or HP(CF₃)₂ to SiVi functions. The novel compounds are characterized by analytical and spectroscopic (IR, NMR, MS) investigations.     

Heteronukleare Metallatomcluster der Typen X4−n[SnM(CO)4P(C6H5)3]n und M2(CO)8 [μ-Sn(X)M (CO)4P(C6H5)3]2 aus Umsetzungen von SnX2 mit M2(CO)8[P(C6H5)3]2 (X = Halogen; M = Mn,Re; n = 2, 3)

Heteronuclear Metal Atom Clusters of the Types X_4?n[SnM(CO)₄P(C₆H₅)₃]_n and M₂(CO)₈[μ-Sn(X)M(CO)₄P(C₆H₅)₃]₂ by Reaction of SnX₂ with M₂(CO)₈[P(C₆H₅)₃]₂ (X = Halogene; M = Mn, Re; n = 2, 3) The compounds of the both types X_4?n[SnM(CO)₄P(C₆H₅)₃]_n (n = 3; M = Mn; X = F, Cl, Br, I. n = 2: M = Mn, Re; X = Cl, Br, I) and M₂(CO)₈[μ-Sn(X)M(CO)₄P(C₆H₅)₃]₂ (M = Mn; X = Cl, I. M = Re; X = Cl, Br, I) are prepared by reaction of SnX₂ with M₂(CO)₈[P(C₆H₅)₃]₂ (M = Mn, Re). Their IR frequencies are assigned. In Re₂(CO)₈[μ-Sn(Cl)Re(CO)₄P(C₆H₅)₃]₂ the central molecule fragment contains a planar Re₂Sn₂ rhombus with a transannular Re? Re bond of 316.0(2) pm. Each of the Sn^IV atoms is connected with the terminal ligands Cl and Re(CO)₄P(C₆H₅)₃. These ligands are in transposition with respect to the Re₂Sn₂ ring. The mean values for the remaining bond distances (pm) are: Sn? Re = 274.0(3); Sn? Cl = 243(1), Re? C = 176(5), Re? P = 242.4(9), C? O = 123(5). The factors with an influence on the geometrical shape of such M₂Sn₂ rings (M = transition metal) are discussed.     

The electronic structure of all-trans-polyenes C2nH2n+2, n = 3–7

The electronic structure of the C_2nH_2n+2 trans-polyenes, n = 3–7, is calculated by the Discrete Variational X_α method (DVM -X_α). The valence ionization potentials (IP ) calculated using the Clementi double zeta basis agree with the known experimental data within several tenths an electron volt. However, the DVM energies of the π → π* optical excitations are systematically underestimated by 0.8–1.0 eV. For polyenes with equal C—C bond lengths, the computed energies of the first optical transitions are smaller than those of polyenes with alternating C—C bond lengths. The charge distribution in polyenes is analyzed in the framework of a Mulliken scheme. The composition of the frontier molecular orbitals (MO ) is analyzed.     

Hypervalent Pentafluoroethylgermanium Compounds, [(C2F5)nGeX5−n]− and [(C2F5)3GeF3]2− (X=F,Cl; n=2–5)

This paper gives an account on hypervalent fluoro‐ and chloro(pentafluoroethyl)germanium compounds. The selective synthesis of the tris(pentafluoroethyl)dichlorogermanate salt [PNP][(C₂F₅)₃GeCl₂] as well as its X‐ray structural analysis is described. As a representative example for pentafluoroethylfluorogermanates, the synthesis and structure of 2,4,6‐triphenylpyryliumtris(pentafluoroethyl)difluorogermanate [C₂₃H₁₇O][(C₂F₅)₃GeF₂] is reported. Fluoride‐ion affinities for pentafluoroethylgermanes were calculated using quantum chemical methods, disclosing (C₂F₅)₃GeF as a weaker Lewis acid than (C₂F₅)₃SiF or (C₂F₅)₃PF₂. The theoretical results were confirmed by experiments and give the basis of a synthetic protocol for (C₂F₅)₃GeF. Pentakis(pentafluoroethyl)germanate [PPh₄][Ge(C₂F₅)₅] was detected as an intermediate during the synthesis of [PPh₄][(C₂F₅)₄GeF] starting from tris(pentafluoroethyl)difluorogermanate and LiC₂F₅.     

Ansa‐Complexes of [Mn(η5‐C5H5)(η6‐C6H6)]: Preparation,Characterization, and Reactivity of [n]Manganoarenophanes (n=1, 2, 3)

We report the synthesis of [n]manganoarenophanes (n=1, 2) featuring boron, silicon, germanium, and tin as ansa‐bridging elements. Their preparation was achieved by salt‐elimination reactions of the dilithiated precursor [Mn(η⁵‐C₅H₄Li)(η⁶‐C₆H₅Li)]?pmdta (pmdta=N,N,N′,N′,N′′‐pentamethyldiethylenetriamine) with corresponding element dichlorides. Besides characterization by multinuclear NMR spectroscopy and elemental analysis, the identity of two single‐atom‐bridged derivatives, [Mn(η⁵‐C₅H₄)(η⁶‐C₆H₅)SntBu₂] and [Mn(η⁵‐C₅H₄)(η⁶‐C₆H₅)SiPh₂], could also be determined by X‐ray structural analysis. We investigated for the first time the reactivity of these ansa‐cyclopentadienyl–benzene manganese compounds. The reaction of the distannyl‐bridged complex [Mn(η⁵‐C₅H₄)(η⁶‐C₆H₅)Sn₂tBu₄] with elemental sulfur was shown to proceed through the expected oxidative addition of the Sn?Sn bond to give a triatomic ansa‐bridge. The investigation of the ring‐opening polymerization (ROP) capability of [Mn(η⁵‐C₅H₄)(η⁶‐C₆H₅)SntBu₂] with [Pt(PEt₃)₃] showed that an unexpected, unselective insertion into the C_ipso?Sn bonds of [Mn(η⁵‐C₅H₄)(η⁶‐C₆H₅)SntBu₂] had occurred.