Vibrational spectra of cyclopropenes. I. IR spectra of 3,3-disubstituted cyclopropenes

The IR spectra were measured and the vibrational problem was solved for a series of 3,3-disubstituted cyclopropenes [R¹: CH₃; R²: C(CH₃)₃ (I), C₆H₅ (II), CC–C(CH₃)₃ (III), CCH (IV)]. It was shown that a number of vibrations of the cyclopropene ring [symmetrical vibration of the ring, stretching and deformational (planar and out-of-plane) vibrations of the vinyl C–H bonds] are characteristic in frequency and form. On the basis of an analysis of the influence of a substituent at the C³ atom on the force field and the frequencies of the characteristic vibrations, it was concluded that the effect of conjugation of the substituent with _Walsh of the MO of the ring on the distribution of electron density in the ring plays a determining role.St. Petersberg University. Translated from Zhurnal Strukturnoi Khimii, Vol. 34, No. 1, pp. 112–124, January–February, 1993.     

The pKR+ values for coordinated propargyl cations [Cp2M2(CO)4(μ-η2,η3-HC≡CCR1R2)]+ (M = Mo,W)

The pK_R+ values for metal-stabilized carbocations [Cp₂M₂(CO)₄(-²,³-HCCCR¹R²)]⁺ (M = Mo, W) containing primary (R¹ = R² = H), secondary (R¹ = H, R² = Me), or tertiary (R¹ = R² = Me) coordinated propargyl cations were measured in 50% aqueous acetonitrile. Their stability increases from the tertiary to primary cation, and the stability of the tungsten-containing cations is higher than that of the corresponding molybdenum analogs.     

Cyclosilethynes containing exocyclic cyclopentyl and cyclohexyl groups

The reaction of BrMgCCSiMe₂CCSiMe₂CCSiMe₂CCSiMe₂CCMgBr with chloro(cyclopentyl)(methyl)silane in a large excess of THF gave 1-cyclopentyl-1,4,4,7,7,10,10,13,13-nonamethyl-1,4,7,10, 13-pentasilacyclopentadeca-2,5,8,11,14-pentayne. Similarly, 1,10-di(cyclopentyl)- or 1,6-di(cyclopentylmethyl)-1,4,4,7,7,10,13,13,16,16-decamethyl-1,4,7,10,13,16-hexasilacyclooctadeca-2,5,8,11,14,17-hexaynes were synthesized from BrMgCCSiMe₂CCSiMe₂CCMgBr and dichloro(cyclopentyl)methylsilane or dichloro(cyclopentylmethyl)(methyl)silane. Condensation of Me₂Si(CCMgBr)₂ with dichloro(cyclohexyl)-methylsilane afforded 1,7-di(cyclohexyl)-1,4,4,7,10,10-hexamethyl-1,4,7,10-tetrasilacyclododeca-2,5,8,11-tetrayne.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 8, 2004, pp. 1282–1284.Original Russian Text Copyright © 2004 by O. Yarosh, Zhilitskaya, N. Yarosh, Albanov, Klyba, Voronkov.This revised version was published online in April 2005 with a corrected cover date.     

3-Phenoxy- and 3-phenylthio-1-propynyl substituted derivatives of silicon and germanium

Reactions of bromomagnesiopropargyl phenyl ethers and their isostmctural sulfides BrMgCCCH₂XPh (X = O, S) with MeVinSiCl₂, Me(CH₂Cl)SiCl₂, EtSiHCl₂, and Me₂SiHCl afforded the corresponding 3-phenoxy- and 3-phenylthio-1-propynyl substituted derivatives of silicon (PhXCH₂CC)₂SiRR¹ and PhXCH₂CCSiHMe₂ (X = O, S). Reactions of the above-mentioned Iotsitch reagents with GeCl₄ led to the corresponding germanium derivatives (PhXCH₂CC)₄Ge (X = O, S).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 511–513, March, 1994.     

Copper(I) π-Complexes with Alkyne Ligands: Synthesis and Crystal Structure of M[CuCl2(HOCH2C≡CCH2OH)] (M = K+, NH+ 4)

Crystals of anionic complexes of the composition M[CuCl₂(HOCH₂CCCH₂OH)], where M = NH₄ ⁺ (I), K⁺ (II), were isolated from concentrated aqueous solutions of CuCl and MCl (M = NH₄ ⁺, K⁺) in the presence of 2-butyne-1,4-diol. Their structures were studied by X-ray diffraction analysis. Isostructural crystals I and II are orthorhombic; Z = 8, space group Ibam; a = 6.735(1) and 6.666(2) Å, b = 17.206(3) and 16.874(6) Å, c = 15.172(3) and 15.032(4) Å, V = 1758(1) and 1691(1) ų, respectively. The compounds are built of individual [CuCl₂(HOCH₂CCCH₂OH)] anions; the NH₄ ⁺ (I) or K⁺ (II) cations are arranged in the voids between the anions. The -coordinated Cu(I) atoms have trigonal-planar environment of two chlorine atoms and CC bond of the 2-butyne-1,4-diol molecule. The Cu–(CC) distances in the -core are 1.892(4) and 1.887(6) Å, CC are 1.233(5) and 1.228(5) Å in I and II, respectively. In complex I, additional hydrogen bonds Cl···H–NH₃ (Cl···H 2.43(4) Å) and O···H–NH₃ (O···H 1.97(3) Å) stabilize the structure.     

Free Radical Reactions of N2O Molecules

Experimental data are presented on the spectral (ESR, IR, and optical) and thermochemical characteristics of a complex between the (Si–O)₃Si^.radical and an N₂O molecule. The rate constants of separate reactions in the systems (Si–O)₃Si^.+ N₂O and (Ge–O)₃Ge^.+ N₂O are found. The results of quantum chemical calculations of potential energy surfaces and spectral characteristics are presented for the following systems: H^.+ N₂O, H₃C^.+ N₂O, H₃Si^.+ N₂O, F₂HSi^.+ N₂O, F₃Si^.+ N₂O, and F₃Ge^.+ N₂O. The latter three systems served as molecular models for experimentally found systems. Based on experimental and theoretical data, the product of N₂O addition to (Si–O)₃Si^.has the structure Si–N=N–O^.. The reactions of free radicals H^., H₃C^., H₃Si^., F₂HSi^., F₃Si^., (Si–O)₃Si^., and (Ge–O)₃Ge^.with N₂O are compared. The spectrum of optical absorbance of the (Si–O)₃Si–O^.radical is recorded and qualitatively characterized.     

Mechanisms of Heterogeneous Processes in the System SiO2 + CH4: I. Methane Chemisorption on a Reactive Silica Surface

Experimental and quantum chemical study of reactive silica surface methylation is carried out. The main product of the reaction is the (Si–O)₂Si(H)(CH₃) groups, which are formed via a radical-chain process with the participation of methane molecules and paramagnetic and diamagnetic defects on the oxide surface. Spectral (optical and IR) characteristics of the groups participating in the process (Si–O)₂Si^·–CH₃, (Si–O)₂Si(H)(CH₃), and (Si–O)₂Si(CH₃)(CH₃) are determined. Information on the kinetics of separate steps of the process is obtained including rate constants and the activation energies of steps.     

Kinetics of Intramolecular Hydrogen Atom Transfer in the Radicals >Si(O·)(R) (R = H,D, CH3, CD3, and C2H5)

Methods are developed for obtaining oxy radicals by the photodecomposition and thermal decomposition of precursors (Si–O)₂Si(N=N–O^·)(R) and (Si–O)₂Si(O–C^·=O)(R). The mechanism of these processes is established. Kinetic data are obtained for the reaction of hydrogen atom transfer in oxy radicals (Si–O)₂Si(O^·)(R) (R = H, D, CH₃, CD₃, and C₂H₅). The activation energies of hydrogen atom transfer are found for three-, four-, and five-membered transition states: 13.5 ± 1, 18 ± 1, and <10 kcal/mol, respectively. For the reaction of H(D) atom transfer in the (Si–O)₂Si(O^·)(H(D)) radical, the kinetic isotope effect is found. Quantum-chemical calculations were used to determine the structures of transition states in the studied processes. Experimental studies were carried out using ESR spectroscopy.     

Diacetylenic Derivatives of Fe2(CO)6(μ-EE′): Spectroscopic Investigations of Fe2(CO)6{μ-EC(H) = C(C≡ CMe)E′} (E = E′, E ≠ E′; E, E′ = S, Se, Te)

The diacetylenic adducts, Fe₂(CO)₆{-EC(H) = C(C CMe)E} (E = E, E E; E, E = S, Se, Te) (1–8) have been obtained from the room temperature stirring of Fe₂(CO)₆(-EE) with HC CC CMe in methanol solvent containing sodium acetate. Compounds 1–8 have been characterized by IR and multinuclear NMR (¹H, ¹³C, ⁷⁷Se, and ^l25Te) spectroscopy. Trends in the chemical shifts of ⁷⁷Se and ¹²⁵Te NMR spectra of Fe₂(CO)₆{-EC(H) = C(C CMe)E} with a variation of EE are discussed.     

Simulation of the reaction path for the nucleophilic addition >O...C≡N from X-ray structural data

An X-ray structural investigation of 1-amino-5-ethyl-5-(hydroxyisopropoxymethyl)-2,3,3-tricyano-1-cyclopentene (1) and 5-acetyl-1-amino-4-butyl-2,3-dicyano-3-methoxyimidoyl-5-methyl-1-cyclopentene (2) has been carried out. Intramolecular non-bonded >O...CN interactions with the parameters: O...C 3.010(1) and 2.534(1) A, angles O...CN 99.3(2) and 117.5(2), C...C N 178.2(3) and 175.4(2)° have been found in both structures. A comparison of the structural parameters characterizing the non-bonded interactions in molecules1 and2 with the literature data has shown that the effectiveness of the interaction is determined not only by the O...-CN distance. It has been established that one of the parameters determining the non-bonded O...-CN interactions is the torsion angle R-O...CN.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1050–1054, June, 1993.     

Synthesis, Characterization and Luminescence Studies of Trinuclear Rhenium–Cobalt Mixed-Metal Alkynyl Complexes Containing a Tetrahedral Co2C2 Cluster Unit

The reaction of rhenium(I) diynyl complexes [Re(CO)₃(N–N)(CC--CCH)] [N–N = ^tBu₂bpy (1), bpy (2)] with Co₂(CO)₈ in THF yielded a new class of luminescent trinuclear rhenium–cobalt mixed-metal alkynyl complexes, [Co₂{-HC₂CC[Re(CO)₃(N–N)]}(CO)₆] [N–N = ^tBu₂bpy (3), bpy (4)]. Their luminescence and electrochemical properties have also been studied.     

Calculations of the chemical shifts of E2s and E2p of Si in model clusters of an SiO2 surface

The electronic configuration of the HOSiO₃ ^3– cluster, which simulates an isolated OH group on an SiO₂ surface, has been calculated by the SCF-X-scattered-wave method with overlapping spheres. The calculation of the binding energies of the Si core electrons confirmed the previously drawn conclusion [see Teor. Éksp. Khim.,16, No. 4, 458 (1980)] that the formation of pairs of ions (Si⁺, SiO^–) and radicals (Si·, SiO·) upon the dehydroxylation of SiO₂ should be accompanied by negative chemical shifts of E_2s and E_2p of Si, while the formation of di- and trisiloxane bridges should be accompanied by positive chemical shifts. A comparison of the values of E_2s and E_2p of Si for various clusters was conducted with the use of corrections which take into account the differences in the radii of the Watson spheres. Extrapolation of the dependence of qSi on E_2s and E_2p of Si revealed that the charge of Si in crystalline silicon is equal to 0.6–0.8. The height of the barrier to the hindered rotation of a surface OH group on SiO₂ calculated in the framework of the model adopted is equal to 0.052 eV, which is in good agreement with the experimental value (0.038 eV).Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 21, No. 5, pp. 513–522, September–October, 1985.     

Reaktionen mit phosphororganischen Verbindungen, 17. Mitt.: Zur Oxydation von β-Oxophosphoniumrhodaniden mit Bleitetraacetat

Zusammenfassung Die Oxydation von Phosphoniumrhodaniden (C₆H₅)₃P–CH (Alkyl) CO–CHR₁R₂ SCN mitPbTA liefert in Abhängigkeit von den Resten R₁ und R₂ Verbindungen des Typs R₁R₂C=C=C (SCN) (Alkyl) und die daraus durch 1,3-Umlagerung resultierenden Senföle R₁R₂C(NCS)–CC-Alkyl. Für R₁=R₂=H und R₁=Cl, R₂=C₂H₅ entsteht fast nur die Allenverbindung. Für R₁=H und R₂=Alkyl isoliert man ein Gemisch aus Allenrhodanid und Acetylenverbindung. Wenn R₁=R₂=(–CH₂–CH₂–CH₂–) oder CH₃ darstellen, kommt es zur ausschließlichen Bildung des Acetylensenföls.Aus -Methoxyphosphoniumrhodaniden (C₆H₅)₃P–CH (OCH₃)CH–CHR₁R₂ SCN erhält man bei der Umsetzung mitPbTA R₁R₂CH–CO–CH(OCH₃) (NCS) und R₁R₂CH–CO–CH(OCH₃) (S–CO–CH₃).

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The oxidation of phosphoniumrhodanides (C₆H₅)₃P–CH (Alkyl)CO–CHR₁R₂ SCN with lead tetraacetate results in the formation of R₁R₂C=C=C=(SCN) (alkyl) type compounds, dependent on the substituents R₁ and R₂ sometimes followed by a 1,3-rearrangement to mustard oils R₁R₂C(NCS)–CC–alkyl. The case R₁=R₂=H and R₁=Cl, R₂=C₂H₅ yields almost exclusively the allenic compound. With R₁=H and R₂-alkyla mixture of allene rhodanide and the acetylenic compound is isolated. If R₁ and R₂ stand for –CH₂–CH₂CH₂– or CH₃, only the mustard oil with an acetylenic group is produced.Upon the oxidation of (C₆H₅)₃P–CH(OCH₃)CO–CHR₁R₂ SCN^– we observed formation of R₁R₂CH–CO–CH(OCH₃) (NCS) and R₁R₂CH–CO–CH(OCH₃) (S–CO–CH₃).

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Mit 5 Abbildungen

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Herrn Prof. Dr.L. Schmid zum 70. Geburtstag gewidmet.

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16. Mitt.:Elisabeth Werner undE. Zbiral, Angew. Chem.79, 899 (1967).     

Disproportionation of the alkynyl derivatives of alkali metal aluminum hydrides in electron-donor solvents

Conclusions The reaction of disproportionation of mixed hydride alkynyl complexes of aluminum in ether, THF, and hexametapol was studied by²⁷Al NMR, and it was shown that the stability of MAlH(3–n)) (CCR)_n, where M=Li, Na, K, and R=Ph, n-Bu decreases in the order: MAlH(CCR)₃ < MAlH₂(CCR)₂ < MAlH₃(CCR). The tendency of these complexes to disproportionate increases with an increase in the solvation of the cation.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 343–349, February, 1984.We would like to thank A. V. Kisin for recording the²⁷Al NMR spectra.     

High resolution infrared spectrum and molecular structure of dichloroacetylene

The infrared spectrum of dichloroacetylene, prepared by the pyrolysis of dichloromaleic anhydride at 1000°C, has been recorded at both low and high resolution. In the low resolution spectrum a number of combination bands not previously observed have been assigned, the infrared active fundamentals have been reassigned, and a center wavenumber value has been determined for the Raman activev ₁ fundamental. The high resolution spectra of a number of fundamental bands, summation bands, and one difference band for the isotopomers,³⁵CICC³⁵CI and³⁵CICC³⁷CI, have been assigned, while a more limited number of bands has been assigned for the species³⁷CICC³⁷CI and³⁵CI¹³CC³⁵CI. The resultant rotational and vibration-rotation constants have been used to obtainr _o,r _e,r _s, and partial r_s structural parameters. The most reliable bond lengths are obtained from the partialr _s treatment and are 164.105(53) pm for the C-CI bond and 119.203(79) pm for the CC bond.     

Unusual condensation of propargylamine. Generation of the 1,3-di(propargylimino)propane anion coordinated to the cobalt(iii) atom

The reaction of propargylamine with the hexanuclear complex Co^II ₆(₃-OH)₂(OOCCMe₃)₁₀(HOOCCMe₃)₄ or the polymer [Co(OH)_n(OOCCMe₃)_2–n]_x under an argon atmosphere afforded the unstable paramagnetic tetramine complex Co^II(OOCCMe₃)₂(H₂NCH₂CCH)₄ (1). In air, if an excess of propargylamine is present, the latter complex is transformed into the complex Co^III(OOCCMe₃)₂(NH₂CH₂CCH)₂[²-N,N"-(HCCCH₂N=CHCHCH=N—CH₂CCH)] (2) containing a new ligand, viz., the 1,3-di(propargylimino)propane anion, which is a formal analog of the acetylacetonate anion. In contrast to propargylamine, 1,3-diaminopropane reacted with the Co^II trimethylacetate clusters in air to produce the cationic complex [Co^III{1,3-(NH₂)₂(CH₂)₃}₂(OOCCMe₃)₂]⁺OOCCMe₃ ^– (3) without entering into condensation reactions. The structures of the resulting complexes were determined by X-ray diffraction analysis.     

Synthesis and Crystal Structure of Diaqua(2.2.2-Cryptand)strontium Dichloride Trihydrate

Absract—Diaqua(2.2.2-Cryptand)strontium dichloride trihydrate [Sr(2.2.2-Crypt)(H₂O)₂]²⁺ · 2Cl^– · 3H₂O (I) was prepared and studied by X-ray diffraction. The triclinic structure of I (space group P , a = 9.152 Å, b = 10.140 Å, c = 15.219 Å, = 88.84°, = 88.19°, = 87.62°, Z = 2) was solved by the direct method and refined by full-matrix least-squares calculations in the anisotropic approximation to R = 0.050 for 4188 independent reflections (CAD4 automated diffractometer, CuK radiation). The structure contains the [Sr(2.2.2-Crypt)(H₂O)₂]²⁺ host–guest cation. The Sr²⁺ cation resides in the 2.2.2-cryptand cavity and is coordinated by all eight heteroatoms (6O + 2N) of the cryptand ligand and by two O atoms of water molecules. The Sr²⁺ coordination polyhedron (C.N. 10) is a highly distorted dibase-centered two-cap trigonal prism. The crystal structure of I contains a branched system of ion–ion (intermolecular) hydrogen bonds O(w)–H···Cl^–, which connect the complex cations, the Cl^– anions, and the crystal water molecules to form infinite thick layers parallel to the yz plane.     

Photochemistry of Aliphatic Nitroxide Radicals Grafted onto Activated Aerosil Surface

The mechanism of photoinduced transformations of nitroxide radicals SiON(O^·)CH₃ (I) and SiOCH₂N(O^·)CH₃ (II) obtained on the activated aerosil surface was studied. The nitroxides were photolyzed with 436-nm light at 77 K. It was shown that the action of light in the long-wavelength absorption band corresponding to the n–* transition resulted in the dissociation of the O–N or C–N bond in radicals I or II, respectively. The quantum yields of these reactions were found to be 0.6 and 0.002, respectively.     

Syntheses,crystal structures and magnetic properties of two honeycomb-layered bimetallic assemblies,K2[NiII(cyclam)]3[FeII(CN)6]2 · 12H2O and [NiII(cyclam)]3[FeIII(CN)6]2 · 16H2O

Two bimetallic assemblies, K₂[Ni^II(cyclam)]₃[Fe^II(CN)₆]₂ · 12H₂O (1) and [Ni^II(cyclam)]₃[Fe^III(CN)₆]₂ · 16H₂O (2) (cyclam = 1,4,8,11-tetraazacyclotetradecane), were obtained by reaction of K₄[Fe(CN)₆] and [Ni(cyclam)](ClO₄)₂ in aqueous media at different temperatures. Their crystals were structurally determined and magnetic properties were studied. Both of the compounds have honeycomb-layered structures, which are formed by Fe₆Ni₆ units linked through the cyanide bridges. Structure (1) consists of polyanions containing Ni^II–NC–Fe^II linkages and K⁺ cations, while structure (2) is a two-dimensional neutral layer containing Ni^II–NC–Fe^III linkages. The magnetic properties of (1) and (2) have been investigated in the 5–300 K range. Compound (1) exhibits a weak antiferromagnetic interaction with Weiss constant = –0.35 K; compound (2) shows ferromagnetic intralayer and antiferromagnetic interlayer interactions.     

Intensity of the η(C≡C) Bands in the IR Spectra of Acetylene Derivatives and σR 0 Constants of Organosilicon,Organogermanium, and Organotin Substituents

The integral absorptivities of shape-characteristic (CC) bands in the IR spectra of 66 acetylene derivatives RCCX (R = H, Me₃M; X are inorganic and organic substituents) are related by a common linear equation to the _R ⁰ constants of the R and X substituents. The _R R⁰ constants of 10 Alk₃M substituents were calculated. The _R ⁰, _R , and _R ⁺ constants of Me₃M substituents were analyzed. The positive _R ⁰ values (0.12, 0.06, and 0.04 for R = Si, Ge, and Sn, respectively) suggest that in the ground electronic state of Me₃MCCX molecules the resonance acceptor effect of the Me₃M substituents (d, conjugation) prevails over donor (, conjugation). The first effect attenuates and the second enhances as the atomic number of M increases.