Unconventional H‐bonds: SH···N interaction

Quantum calculations at the MP2/aug‐cc‐pVDZ level are used to analyze the SH···N H‐bond in complexes pairing H₂S and SH radical with NH₃, N(CH₃)₃, NH₂NH₂, and NH₂N(CH₃)₂. Complexes form nearly linear H‐bonds in which the S? H covalent bond elongates and shifts its stretching frequency to the red. Binding energies vary from 14 kJ/mol for acceptor NH₃ to a maximum of 22 kJ/mol for N(CH₃)₃ and N(CH₃)₂NH₂. Analysis of geometric, vibrational, and electronic data indicate that the SH···N interaction involving SH is slightly stronger than that in which the closed‐shell H₂S serves as donor. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

Difluoromethylation of Amines with Zn(CF3)Br · 2 CH3CN,Cd(CF3)2 · 2 CH3CN and the System Bi(CF3)3/AlCl3

The reactions of Zn(CF₃)Br · 2 CH₃CN, Cd(CF₃)₂ · 2 CH₃CN or Bi(CF₃)₃/AlCl₃ with tertiary amines lead to the formation of quaternary ammonium salts of the general formula [R₃NCF₂H]X. The reaction of 4‐N,N‐dimethylaminopyridine with Zn(CF₃)Br · 2 CH₃CN yields (N‐difluoromethyl)‐4‐N,N‐dimethylaminopyridinium bromide. Bi(CF₃)₃/AlCl₃ reacts with 1,4‐diazabicyclo[2.2.2]octane to form a mixture of mono‐ and bis(difluoromethylammonium) salts.     

Absolute Rate Constants for the Addition of Cyanomethyl (·CH2CN) and (tert-Butoxy)carbonylmethyl (·CH2CO2C(CH3)3) radicals to alkenes in solution

Absolute rate constants and their temperature dependence were determined by time-resolved electron spin resonance for the addition of the radicals ·CH₂CN and ·CH₂CO₂C(CH₃)₃ to a variety of mono- and 1,1-disubstituted and to selected 1,2- and trisubstituted alkenes in acetonitrile solution. To alkenes CH₂?CXY, ·CH₂CN adds at the unsubstituted C-atom with rate constants ranging from 3.3·10³ M ^?1S ^?1 (ethene) to 2.4·10⁶ M ^?1S ^?1 (1,1-diphenylethene) at 278 K, and the frequency factors are in the narrow range of log (A/M ^?1S ^?1) = 8.7 ± 0.3. ·CH₂CO₂C(CH₃)₃ shows a very similar reactivity with rate constants at 296 K ranging from 1.1·10⁴ M ^?1S ^?1 (ethene) to 10⁷ M ^?1S ^?1 (1,1-diphenylethene) and frequency factors log (A/M ^?1S ^?1) = 8.4 ± 0.1. For both radicals, the rate constants and the activation energies for addition to CH₂?CXY correlate well with the overall reaction enthalpy. In contrast to the expectation of an electro- or ambiphilic behavior, polar alkene-substituent effects are not clearly expressed, but some deviations from the enthalpy correlations point to a weak electrophilicity of the radicals. The rate constants for the addition to 1,2- and to trisubstituted alkenes reveal additional steric substituent effects. Self-termination rate data for the title radicals and spectral properties of their adducts to the alkenes are also given.     

The Homoleptic U(NCSe)84– Anion in (Pr4N)4U(NCSe)8·2CFCl3 and Th(NCSe)4(OP(NMe2)3)4·0.5CH3CN·0.5H2O: First Structurally Characterised Actinide Isoselenocyanates

The neutral thorium complex Th(NCSe)₄(OP(NMe₂)₃)₄ and homoleptic octa(isoselenocyanato)uranate anion U(NCSe)₈^4– in (Pr₄N)₄U(NCSe)₈·2CFCl₃ ( 1 ) were synthesised and structurally characterised. (Pr₄N)₄U(NCSe)₈·2CFCl₃ contains the U^IV anion U(NCSe)₈^4– and was characterised using IR spectroscopy and single‐crystal X‐ray diffraction. Th(NCSe)₄(OP(N(CH₃)₂)₃)₄·0.5CH₃CN·0.5H₂O ( 2 ) was characterised using IR and Raman spectroscopy, as well as ³¹P{¹H}, ¹⁵N{¹H}, ¹⁴N{¹H}, ¹³C{¹H}, ¹H and ⁷⁷Se NMR spectroscopy and structurally characterised using single‐crystal X‐ray diffraction. The U(NCSe)₈^4– anion and Th(NCSe)₄(OP(N(CH₃)₂)₃)₄·0.5CH₃CN·0.5H₂O complex are the first structurally characterised actinide‐isoselenocyanates. The crystal structures shows an approximate square antiprismatic arrangement of the ligands around the actinide(IV) atoms.     

Kristallstruktur und Schwingungsspektrum von (H2NPPh3)2[SnCl6]·2CH3CN

Crystal Structure and Vibrational Spectrum of (H₂NPPh₃)₂[SnCl₆]·2CH₃CN Single crystals of (H₂NPPh₃)₂[SnCl₆]·2CH₃CN ( 1 ) were obtained by oxidative addition of tin(II) chloride with N‐chloro‐triphenylphosphanimine in acetonitrile in the presence of water. 1 is characterized by IR and Raman spectroscopy as well as by a single crystal structure determination: Space group , Z = 2, lattice dimensions at 193 K: a = 1029.6(1), b = 1441.0(2), c = 1446.1(2) pm, α = 90.91(1)°, β = 92.21(1)°, γ = 92.98(1)°, R₁ = 0.0332. 1 forms an ionic structure with two different site positions of the [SnCl₆]^2? ions. One of them is surrounded by four N‐hydrogen atoms of four (H₂NPPh₃)⁺ ions, four CH₃CN molecules form N–H···N≡C–CH₃ contacts with the other four N‐hydrogen atoms of the cations. Thus, 1 can be written as [(H₂NPPh₃)₄(CH₃CN)₄(SnCl₆)]²⁺[SnCl₆]^2?.     

Synthesis,Characterization, and Crystal Structures of [N(CH3)4]2[B12H12] and [N(CH3)4]2[B12H12] · CH3CN

Bis(tetramethylammonium) dodecahydrododecaborate, [(CH₃)₄N]₂[B₁₂H₁₂], and bis(tetramethylammonium) dodecahydrododecaborate acetonitrile, [(CH₃)₄N]₂[B₁₂H₁₂] · CH₃CN, were synthesized and characterized via Infrared, ¹H and ¹¹B NMR spectroscopy. [(CH₃)₄N]₂[B₁₂H₁₂] crystallizes isopunctual to the alkali metal dodecaborates. The crystal structure of [(CH₃)₄N]₂[B₁₂H₁₂] · CH₃CN was determined from single crystal data and refined in the orthorhombic crystal system (Pcmn, no. 62, a = 898.68(8), b = 1312.85(9) c = 1994.5(1) pm, R(|F| , 4σ) = 5.9%, wR(F²) = 18.3%). Here, the geometry of the dodecaborate anion is that of an almost ideal icosahedron, less distorted than most other dodecaborates known. By low‐temperature Guinier‐Simon diffractometry phase transitions were detected for [(CH₃)₄N]₂[B₁₂H₁₂] and [(CH₃)₄N]₂[B₁₂H₁₂] · CH₃CN at –70 and –15 °C, respectively.     

Die Konstitution des Tetramethylammoniumsilicats der Zusammensetzung 1,0 N(CH3)4OH 1,0 SiO2 · 8,0–8,3 H2O

By means of paperchromatographic, kinetic and X-ray methods it is shown that the tetramethylammonium silicate of the composition 1 N(CH₃)₄OH · 1 SiO₂ · ～8 H₂O has not – as hitherto supposed – the constitution of a poly- or phyllosilicate, but that of a tetra-anhydrido-bis-cyclotetrasilicate (double-fourringsilicate), [(CH₃)₄N]₈[Si₈O₂₀] · ～69 H₂O. Its trimethylsilylation by means of hexamethyldisiloxane gives the corresponding, crystalline trimethylsilyl ester [(CH₃)₃Si]₈[Si₈O₂₀], which has been characterised by mass spectroscopy.     

[{(CH3)3Si}3C–Li–C{Si(CH3)3}3][Li · 3(OC4H8)] und {(CH3)3Si}3C–Li · O=C(Si(CH3)3)2, zwei neue Addukte des Lithium‐trisylmethanids

[{(CH₃)₃Si}₃C–Li–C{Si(CH₃)₃}₃][Li · 3(OC₄H₈)] and {(CH₃)₃Si}₃C–Li · O=C(Si(CH₃)₃)₂, two New Adducts of Lithium Trisylmethanide Sublimation of (Tsi–Li) · 2 THF (Tsi = –C(Si(CH₃)₃)₃) at 180 °C and 10^–4 hPa gives (Tsi–Li) · 1.5 THF in very low yield. The X‐ray structure determination shows an almost linear [Tsi–Li–Tsi]^– anion connected by short agostic Li…C contacts with the threefold THF‐coordinated Li‐cation. Base‐free Tsi–Li, solved in toluene is decomposed by oxygen, forming the strawberry‐colored ketone O=C(SiMe₃)₂, which forms an 1 : 1 adduct with undecomposed Tsi–Li. The X‐ray structure elucidation of this compound is also discussed.     

Theoretical study of stabling function of the NO to the (CH3)3CO · radical

The stabling function of the NO to the (CH₃)₃CO · radical has been theoretically investigated. Density functional theory (DFT) calculations are performed to optimize the geometries of relevant species. The single‐point energy is evaluated at CCSD(T)/6‐31++G** level. Three reaction channels of (CH₃)₃CO · + NO in the singlet state are considered. The calculations indicate that NO is a stable reagent of active radical (CH₃)₃CO. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005     

Schwingungsspektren und Kraftkonstanten der Übergangsreihen OP(N(CH3)2)3 – OP(CH3)3 und SP(N(CH3)2)3 – SP(CH3)3

Vibrational Spectra and Force Constants of the Series OP(N(CH₃)₂)₃ – OP(CH₃)₃ and SP(N(CH₃)₂)₃ – SP(CH₃)₃ The vibrational spectra (IR and Raman) of the compounds of the title series are recorded and assigned to the normal vibrations. By a simplified force field the valence force constants are calculated and discussed. The results are compared with those of the NMR spectroscopy.     

Über Eigenschaften und Reaktivität von Aluminiumtrichlorid · Ethanthiol und Galliumtrichlorid · Ethanthiol

On Some Properties and the Reactivity of Trichloroaluminium · Ethanthiol and Trichlorogallium · Ethanthiol Complexes The synthesis of aluminiumtrichloride · ethanthiol as well as galliumtrichloride · ethanthiol is given. The reactions of these 1:1-adducts with the Lewis bases N(CH₃)₃. P(CH₃)₃, O(C₂H₅)₂ and S(CH₃)₂ and with the compounds (CH₃)₃SiSCH₃ and Pb(SCH₃)₂ are discussed, the reaction products are investigated. Spectra as well as some chemical and physical properties of the starting material and the products are reported.     

Synthese und Kristallstruktur des heterobimetallischen Diorganozinndichlorids (FcN,N)2SnCl2 (FcN,N—: (η5‐C5H5)Fe{(η5‐C5H3[CH(CH3)N(CH3)CH2CH2NMe2]‐2}—)

Synthesis and Crystal Structure of the Heterobimetallic Diorganotindichloride (FcN, N)₂SnCl₂ (FcN, N^—: (η⁵‐C₅H₅)Fe{η⁵‐C₅H₃[CH(CH₃)N(CH₃)CH₂CH₂NMe₂]‐2}^—) The heterobimetallic title compound [(FcN, N)₂SnCl₂] ( 1 ) was obtained by the reaction of [LiFcN, N] with SnCl₄ in the molar ratio 1:1 in diethylether as a solvent. The two FcN, N^— ligands in 1 are bound to Sn through a C‐Sn σ‐bond; the amino N atoms of the side‐chain in FcN, N^— remain uncoordinated. The crystals contain monomeric molecules with a pseudo‐tetrahedral coordination at the Sn atom: Space group P2₁/c; Z = 4, lattice dimensions at —90 °C: a = 9.6425(2), b = 21.7974(6), c = 18.4365(4) Å, β = 100.809(2)°, R1_obs· = 0.051, wR2_obs· = 0.136.     

Nature of MoH···I bonds in Cp2Mo(L)H···I‐C≡C‐R Complexes (L=H,CN, PPh2, C(CH3)3; R=NO2, Cl,Br, H,OH, CH3, NH2)

The nature of the MoH···I bond in Cp₂Mo(L)H···I‐C≡C‐R (L= H, CN, PPh₂, C(CH₃)₃; R=NO₂, Cl, Br, H, OH, CH₃, NH₂) was investigated using electrostatic potential analysis, topological analysis of the electron density, energy decomposition analysis and natural bond orbital analysis. The calculated results show that MoH···I interactions in the title complexes belong to halogen‐hydride bond, which is similar to halogen bonds, not hydrogen bonds. Different to the classical halogen bonds, the directionality of MoH···I bond is low; Although electrostatic interaction is dorminant, the orbital interactions also play important roles in this kind of halogen bond, and steric interactions are weak; the strength of H···I bond can tuned by the most positive electrostatic potential of the I atom. As the electron‐withdrawing ability of the R substituent in the alkyne increases, the electrostatic potential maximum of the I atom increases, which enhances the strength of the H···I halogen bond, as well as the electron transfer.     

[Mo2(O2C–CH3)4 · 1/2 {(CH2)6N4} · 1/2 CH2Cl2] – ein Donor‐Akzeptor‐Komplex mit supramolekularer Struktur

[Mo₂(O₂C–CH₃)₄ · ¹/₂ {(CH₂)₆N₄} · ¹/₂ CH₂Cl₂] – a Donor‐Acceptor Complex with Supramolecular Structure Yellow single crystals of [Mo₂(O₂C–CH₃)₄ · ¹/₂ {(CH₂)₆N₄} · ¹/₂ CH₂Cl₂] ( 1 ) have been obtained by the reaction of the silylated phosphaneimine Me₃SiNPEt₃ with [Mo₂(O₂C–CH₃)₄] in dichloromethane solution. 1 forms a three‐dimensional network with linear N–Mo:Mo–N and tetrahedral (CH₂)₆N₄Mo₄ moieties, which is topologically related with the PtS type. Space group P4₂/nnm, Z = 4, lattice dimensions at –70 °C: a = b = 1121.7(1), c = 1395.0(3) pm, R₁ = 0.0413.     

Phosphaniminato-Komplexe des Antimons. Die Kristallstrukturen von [Sb2Cl5(NPMe3)2][SbCl6] · CH3CN und [SbCl(NPPh3)]2[SbCl6]2 · 6 CH3CN

Phosphorane Iminato Complexes of Antimony. The Crystal Structures of [Sb₂Cl₅(NPMe₃)₂][SbCl₆] · CH₃CN and [SbCl(NPPh₃)]₂[SbCl₆]₂ · 6 CH₃CN The title compounds are formed by reaction of antimony pentachloride in acetonitrile solution with the phosphorane iminato complexes SbCl₂(NPMe₃) and SbCl₂(NPPh₃), respectively, which themselves are synthesized by reaction of antimony trichloride with Me₃SiNPR₃ (R = Me, Ph). The complexionic compounds are characterized by ¹²¹Sb Mössbauer spectroscopy and by crystal structure determinations. [Sb₂Cl₅(NPMe₃)₂][SbCl₆] · CH₃CN: Space group P4₁, Z = 4, 3 698 observed unique reflections, R = 0.022. Lattice dimensions at ?60°C: a = b = 1 056.0(1), c = 2 709.6(2) pm. The structure consists of SbCl₆^? ions and cations [Sb₂Cl₅(NPMe₃)₂(CH₃CN)]⁺, in which one Sb^III atom and one Sb^V atom are bridged by the N atoms of the phosphorane iminato ligands. [SbCl(NPPh₃)]₂[SbCl₆]₂ · 6 CH₃CN: Space group P1 , Z = 2, 5 958 observed unique reflections, R = 0.033. Lattice dimensions at ?60°C: a = 989.4(11), b = 1 273(1), c = 1 396(1) pm, α = 78.33(7), β = 77.27(8)°, γ = 86.62(8)°. The structure consists of SbCl₆^? ions and centrosymmetric cations [SbCl(NPPh₃)(CH₃CN)₂]₂²⁺, in which the antimony atoms are bridged by the N atoms of the phosphorane iminato ligands.     

Metallboranate und Boranato-metallate. VI. Zur Reaction von Oniumboranaten mit Trimethylamin-Alan: Trimethylamin-boranato-alanat,BH4 · AlH3 · N(CH3) und Onium-alanate

Trimethylamine-alane adds to tetrabutylammonium tetrahydroborate in benzene to yield tetrabutylammonium trimethylamine-tetrahydroborato-trihydroaluminate. The BH₄ group of this novel complex hydrido-anion is bound via a single hydrogen bridge to the aluminium atom. Although there is ir-spectroscopic evidence for the formation of a similar tetraphenylphosphonium salt in the reaction of tetraphenylphosphonium tetra-hydroborate and trimethylamine-alane (employed in excess), the products are tetraphenylphosphonium tetrahydroaluminate and trimethylamine-tetrahydroborato-alane. However, tetraphenylarsonium tetrahydroborate yields triphenylarsine and (CH₃)₃N · AlH₂BH₄ under similar conditions. Tetrabutylammonium, tetraphenylphosphonium and tetraphenylarsonium tetrahydro-aluminates were prepared from the respective tetrahydroborate and LiAlH₄.     

Synthesen und Schwingungsspektren der homoleptischen Acetonitrilkomplex-Kationen [Au(NCCH3)2]+, [Pd(NCCH3)4]2+, [Pt(NCCH3)4]2+ und des Adduktes CH3CN · SbF5. Kristallstrukturen der Salze [M(NCCH3)4][SbF6]2 · CH3CN,M = Pd,Pt

The Syntheses and Vibrational Spectra of the Homoleptic Metal Acetonitrile Cations [Au(NCCH₃)₂]⁺, [Pd(NCCH₃)₄]²⁺, [Pt(NCCH₃)₄]²⁺, and the Adduct CH₃CN · SbF₅. The Crystal and Molecular Structures of [M(NCCH₃)₄][SbF₆]₂ · CH₃CN, M = Pd or Pt Solvolyses of the homoleptic metal carbonyl salts [M(CO)₄][Sb₂F₁₁]₂, M = Pd or Pt, in acetonitrile leads at 50 °C both to complete ligand exchange for the cations as well as to a conversion of the di-octahedral anion [Sb₂F₁₁]^– into [SbF₆]^– and the molecular adduct CH₃CN · SbF₅ according to: [M(CO)₄][Sb₂F₁₁]₂ + 7 CH₃CN → [M(NCCH₃)₄][SbF₆]₂ · CH₃CN + 2 CH₃CN · SbF₅ + 4 CO M = Pd, Pt The monosolvated [M(NCCH₃)₄][SbF₆]₂ · CH₃CN are obtained as single crystals from solution and are structurally characterized by single crystal x-ray diffraction. Both salts are isostructural. The cations are square planar but the N–C–C-sceletial groups of the ligands depart slightly from linearity. The new acetonitrile complexes as well as [Au(NCCH₃)₂][SbF₆] and the adduct CH₃CN · SbF₅ are completely characterized by vibrational spectroscopy.     

Die Kristall- und Molekülstrukturen von In(CH3COO)3 · 2,2′-Dipyridin und In(CH3COO)3 · 1,10-Phenanthrolin – Verbindungen mit Indium der Koordinationszahl 8

Crystal and Molecular Structures of In(CH₃COO)₃ · 2,2′-Dipyridine and In (CH₃COO)₃ · 1,10-Phenanthroline – Compounds of Indium with Coordination Number 8 In(CH₃COO)₃ · 2,2′-dipyridine and In(CH₃COO)₃ · 1,10-phenanthrline crystallize in the monoclinic space group P2₁/c with a = 844.7(3), b = 1 408.8(5), c = 1 466.6(5) pm, β = 84.9(1)°, Z = 4 (dipyridine complex) and a = 811.9(3), b = 1 555.3(5), c = 1 447.3(5) pm, β = 90.6 (1)°, Z = 4 (phenanthroline complex). The structures were determined by the heavy atom method from 2202 and 2617 independent reflections and have been refined by full matrix least-squares methods to R = 3.49 and 4.35%, respectively. In both complexes the acetate ligands and the N-donor ligand are bidentate, In attaining the coordination number 8. The donor atoms are arranged in the form of a distorted dodecahedron. Some distances and angles: see ?Inhaltsübersicht”?.     

Thermal decomposition of di-t-butyl peroxide in the presence of (CH3)2CCH2: Reactions of CH3, (CH3)2ĊCH2CH3, and (CH3)2ĊCH2C(CH3)2CH2CH3 radicals

A study of the reaction initiated by the thermal decomposition of di-t-butyl peroxide (DTBP) in the presence of (CH₃)₂C?CH₂ (B) at 391–444 K has yielded kinetic data on a number of reactions involving CH₃ (M·), (CH₃)₂CCH₂CH₃ (MB·) and (CH₃)₂?CH₂C(CH₃)₂CH₂CH₃ (MBB·) radicals. The cross-combination ratio for M· and MB· radicals, rate constants for the addition to B of M· and MB· radicals relative to those for their recombination reactions, and rate constants for the decomposition of DTBP, have been determined. The values are, respectively, where θ = RT ln 10 and the units are dm^3/2 mol^?1/2 s^?1/2 for k₂/k and k₉/k, s^?1 for k₀, and kJ mol^?1 for E. Various disproportionation-combination ratios involving M·, MB·, and MBB· radicals have been evaluated. The values obtained are: Δ₁(M·, MB·) = 0.79 ± 0.35, Δ₁(MB·, MB·) = 3.0 ± 1.0, Δ₁(MBB·, MB·) = 0.7 ± 0.4, Δ₁(M·, MBB·) = 4.1 ± 1.0, Δ₁(MB·, MBB·) = 6.2 ± 1.4, and Δ₁(MBB·, MBB·) = 3.9 ± 2.3, where Δ₁ refers to H-abstraction from the CH₃ group adjacent to the center of the second radical, yielding a 1-olefin. © 1994 John Wiley & Sons, Inc.     

Zur solvensfreien Darstellung von Tetramethylammoniumsalzen: Synthese und Charakterisierung von [N(CH3)4]2[C2O4], [N(CH3)4][CO3(CH3)], [N(CH3)4][NO2], [N(CH3)4][CO2H] und [N(CH3)4][O2C(CH2)2CO2(CH3)]

Solvent-free Synthesis of Tetramethylammonium Salts: Synthesis and Characterization of [N(CH₃)₄]₂[C₂O₄], [N(CH₃)₄][CO₃CH₃], [N(CH₃)₄][NO₂], [N(CH₃)₄][CO₂H], and [N(CH₃)₄][O₂C(CH₂)₂CO₂CH₃] A general procedure to synthesize tetramethylammonium salts is presented. Several tetramethylammonium salts were prepared in a crystalline state by solvent-free reaction of trimethylamine and different methyl compounds at mild conditions: [N(CH₃)₄]₂[C₂O₄] (cubic; a = 1 114.8(3) pm), [N(CH₃)₄][CO₃CH₃] (P2₁/n; a = 813.64(3), b = 953.36(3), c = 1 131.3(4) pm, β = 90.03(1)°), [N(CH₃)₄][NO₂] (Pmmn; a = 821.2(4), b = 746.5(3), c = 551.5(2) pm), [N(CH₃)₄][CO₂H] (Pmmn; a = 792.8(7), b = 791.7(3), c = 563.3(4) pm) and [N(CH₃)₄][O₂C(CH₂)₂CO₂CH₃] (P2₁; a = 731.1(2), b = 826.4(3), c = 1 025.2(3) pm, β = 110.1(1)°). The tetramethylammonium salts were characterized by IR-spectroscopy and X-ray diffraction. The crystal structures of the methylcarbonate and the nitrite are described.