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1.
Microwave studies (26.5–40 GHz) of further isotopic species of selenoketene formed by pyrolysis of 1,2,3-selenodiazole (12CH212C76,77,82Se, 12CH213C80Se and 13CH212C80Se) and by pyrolysis of 5-deuterio-1,2,3-selenodiazole (12CHD12C78,80Se) are reported. In conjunction with earlier results for 12CH12C78,80Se an rs structure has been derived with distances SeC (1.706 Å), CC (1.303 Å), CH (1.0908 A) and a HCH bond angle of 119.7°. The geometry of the CH2C moiety of selenoketene is closer to allene, CH2CCH2, than to ketene, CH2CO. 相似文献
2.
The reaction of the aromatic azo or imine compounds PhX=NR (X=N or CH; R = alkyl or aryl) and 2-(methylazo)propene, H2CC(CH3)N&.zdbnd;NCH3, with trans-IrCl(N2)(PPh3)2 yields the (ortho) metallated complexes IrHCl(G6H4X=NR)(PPh3)2 and IrHClCHC(CH3)-NNCH3](PPh3)2 respectively.The v(N=N) vibration in IrHCl(C6HZ4N=NPh)(PPh3)2 appears to be drastically lowered with respect to the free ligand vibration. Furthermore, Resonance Raman experiments show that this vibration is strongly coupled to both of the electronic transitions of this compound at longer wavelengths, which therefore must be closely connected with the azo group.1H and 13C NMR spectroscopic data and crystallographic studies of IrHCI(C6H4N=NPh)(PPh3)2 give strong evidence about the nature of the mechanism of these (ortho) metallation reactions. 相似文献
3.
The structural parameters of the completely relaxed 4–21G ab initio geometries of more than 30 basic organic compounds are compared to experimental results. Some ranges for systematic empirical corrections, which relate 4–21G bond distances to experimental parameters, are associated with total energy increments. In general, for the currently feasible comparisons, the following corrections can be given which relate calculated distances to experimental rg parameters and calculated angles to rs-structures For CC single bond distances, deviations between calculated and observed parameters (rg) are in the ranges of ?0.006(2) to ?0.010(2) Å for normal or unstrained hydrocarbons; ?0.011(3) to ?0.016(3) Å for cyclobutane type compounds; and +0.001(5) to +0.004(4) Å for CH3 conjugated with CO. For CO single bonds the ranges are ?0.006(9) to +0.002(3) Å for CO conjugated with CO; and ?0.019(3) to ?0.027(9) Å for aliphatic and ether compounds. A very large and exceptional discrepancy exists for the highly strained ethylene oxide, rs — re = ?0.049(5) Å and in CH3OCH3 and C2H5OCH3 the rs — re differences are ?0.029(5), ?0.040(10) and ?0.025(10) Å. Some of these discrepancies may also be due to deficiencies of the microwave substitution method caused by atomic coordinates close to inertial planes. For CN bonds, two types of NCH3 corrections are from +0.005(6) to ?0.006(6) and from ?0.009(2) to ?0.014(6) Å; and the range for NCO is +0.012(3) to +0.028(4) Å. For isolated CC double bonds the range is + 0.025(2) to +0.028(2) Å. For conjugated CC double bonds the correction is less positive (+0.014(1) Å for benzene). For CO double bonds the corrections are ?0.004(3) to +0.003(3) Å. For bond angles of type HCH, CCH, CCC, CCO, CCO, OCO, NCO and CCC the corrections are of the order of magnitude about 1–2° (or better). Angles centered at heteroatoms are less accurate than that, when hydrogen atoms are involved. Differences in HOC and NHC angles were found in a range of ?2.3(5)° to ?6.2(4)°. 相似文献
4.
The molecular structure of the title compounds have been investigated by gas-phase electron diffraction. Both molecules exist as about equal amounts of the two gauche conformers. There is no evidence for the presence of a syn conformer, but small amounts of this form cannot be excluded. Some of the important distance (ra) and angle (∠α) parameters for 1,1-dichloro-2-bromomethyl-cyclopropane are: r(CH) = 1.095(19) Å, r(C1C2) = 1.476(11) Å, r(C2C3) = 1.517(31) Å, r(CCH2Br) = 1.543(32) Å, r(CCl) = 1.752(6) Å, r(CBr) = 1.950(13) Å, ∠CCBr = 110.5(1.9)°, ∠ClCCl = 111.9(6)°, ∠CCC = 117.5(1.3)°, σ1 (CC torsion angle between CBr and the three-membered ring for gauche-1) = 116.2(5.6)°, σ2 = −132.7(7.6). For 1,1-dichloro-2-cyanomethyl-cyclopropane the parameter values are: r(CH) = 1.101(16) Å, r(C1C2) = 1.498(9) Å, r(C2C3) = 1.544(21) Å, r(C2C4) = 1.497(33) Å, r(CCN) = 1.466(26) Å, r(CN) = 1.165(8) Å, r(CCl) = 1.754(5) Å, ∠CCCN = 113.7(2.0)°, ∠CCC = 122.8(1.6)°, ClCCl = 112.5(4)°, σ1 = 113(13)°, σ2 = −124(10)°. 相似文献
5.
A.R. László Bursics Martin Murray F. Gordon A. Stone 《Journal of organometallic chemistry》1976,111(1):31-42
Bis(cyclopentadienyl)mercury readily undergoes Diels—Alder reactions with RCCR (R = CO2Me or CF3), CF3CFCFCF3, CF3CFCF2, (CF3)2CC(CN)2, C2(CN)4 and PhO to give stable adducts characterised by1H, 19F and 13C NMR, spectroscopy. Similar reactions of CF3CCCF3 and CF3CFCFCF3 with the cyclopentadiene derivatives Me3MC5H5 and (Me3M)2C5H4 (M = Si, Sn) are also described. 相似文献
6.
Helmut Alt Max Herberhold Cornelius G. Kreiter Hans Strack 《Journal of organometallic chemistry》1975,102(4):491-505
The restricted rotation of the olefin ligands L = dimethyl maleate and dimethyl fumarate in complexes of the type C5H5Mn(CO)2L and C5H5Cr(CO)-(NO)L, respectively, has been investigated on the basis of their temperature-dependent 1H NMR spectra. The olefinic ligand is arranged preferably in a position where the CC double bond is parallel to the plane of the cyclopentadienyl ring. The possible stereoisomers are discussed using this model. The 1H NMR spectra of C5H5Cr(CO)(NO)(trans-CH3OOCCHCHCOOCH3) provide direct evidence that the configuration (R or S) at the metal is stable up to 120°C, and that the restricted motion of the olefin is exclusively rotation around the metal—olefin bond. The activation barriers of the olefin rotation are found to be appreciably lower in the C5H5Mn(CO)2L complexes (ΔG≠(TC) 11–12 kcal mol?1) than in the isoelectric C5H5Cr(CO)(NO)L compounds (ΔG≠(TC) 15–20 kcal mol?1). 相似文献
7.
A series of novel phosphaalkenes, YoshPCHP(X)R (Yosh = 2,4,6-tBu3C6H2) has been prepared, as well as the first stable carbodiphosphane, YoshPCPYosh, which has been characterized by elemental analysis, NMR and mass spectroscopy. 相似文献
8.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1993,49(8):1047-1053
Starting from CF3SSCl and (CH3)3SiNSO, the compound S(N-sulfinylimine)-perfluoromethyl-disulphane, CF3SSNSO, has been prepared. The IR, pre-resonant Raman, 19F, 13C and 15N NMR, mass, and UV spectra have been obtained and interpreted.Both Raman studies at different temperatures and those using different excitation radiations reveal the existence of the molecule in one preferred conformation. From these studies a pre-resonant effect can be determined. Its extension is associated with the particular C1 conformation adopted for the molecule. The available spectroscopical data confirm not only the proposed structure for the molecule but are also consistent with a skew [SC(F3) and SN], skew (SS, NS) and cis (SN, SO) conformation regarding the SS and XNSO parts of the molecule. 相似文献
9.
The molecular structure of N(C2H5)2(SiH3) in the gas phase has been determined by electron diffraction. The SiNC2 skeleton is a shallow pyramid, with angles CNC 114.5(12)° and SiNC 120.9(5)°, and the methyl groups lie so that one CC bond lies close to the CNC plane, but the other is almost perpendicular to it. Other important parameters (ra) are: r(SiN) 171.5(3), r(CN) 145.6(4), r(CC) 154.3(8) pm, and ∠NCC 113.6(6)°. 相似文献
10.
11.
M(CO)5X (M = Mn, Re; X = Cl, Br, I) reacts with DAB (1,4-diazabutadiene = R1N=C(R2)C(R2)′=NR′1) to give M(CO)3X(DAB). The 1H, 13C NMR and IR spectra indicate that the facial isomer is formed exclusively. A comparison of the 13C NMR spectra of M(CO)3X(DAB) (M = Mn, Re; X = Cl, Br, I; DAB = glyoxalbis-t-butylimine, glyoxyalbisisopropylimine) and the related M(CO)4DAB complexes (M = Cr, Mo, W) with Fe(CO)3DAB complexes shows that the charge density on the ligands is comparable in both types of d6 metal complexes but is slightly different in the Fe-d8 complexes. The effect of the DAB substituents on the carbonyl stretching frequencies is in agreement with the A′(cis) > A″ (cis) > A′(trans) band ordering.Mn(CO)3Cl(t-BuNCHCHNt-Bu) reacts with AgBF4 under a CO atmosphere yielding [Mn(CO)4(t-BuNCHCHN-t-Bu)]BF4. The cationic complex is isoelectronic with M(CO)4(t-BuNCHCHNt-Bu) (M = Cr, Mo, W). 相似文献
12.
The electronic structures of the ground and excited states of ketene imine (HHCCNH) have been studied by ab initio SCF and CI calculations. The nucleophilic nature of the β carbon with respect to nitrogen has been discussed using calculated electrostatic potentials and by calculated energy differences between the parent and protonated species. The electronically excited 1A″ and 3A″ states are found to be almost degenerate. 相似文献
13.
The structures of tetrachloro-p-benzoquinone and tetrachloro-o-benzoquinone (p- and o-chloranil) have been investigated by gas electron diffraction. The ring distances are slightly larger and the carbonyl bonds slightly smaller than in the corresponding unsubstituted quinones. The molecules are planar to within experimental error, but small deviations from planarity such as those found for the para compound in the crystal are completely compatible with the data. Values for the geometrical parameters (ra distances and bond angles) and for some of the more important amplitudes (l) with parenthesized uncertainties of 2σ including estimated systematic error and correlation effects are as follows. Tetrachloro-p-benzoquinone: D2h symmetry (assumed); r(CO) = 1.216 Å(4), r(CC) = 1.353 Å(6), r(C-C) = 1.492 Å(3), r(C-Cl) = 1.701 Å(3), ∠C-C-C = 117.1° (7), ∠CC-C1 = 122.7° (2), l(CO)= 0.037 Å(5), l(CC) = l(C-C) - 0.008 Å(assumed) = 0.049 Å(7), and l(C-Cl) = 0.054 Å(3). Tetrachloro-o-benzoquinone: C2v symmetry (assumed); r(CO) = 1.205 Å(5), r(CC) = 1.354 Å(9), r(Ccl-Ccl) = 1.478 Å(28), r(Co-Ccl) = 1.483 Å(24), r(Co-Co) = 1.526 Å(2), r(C-Cl)= 1.705 Å(3), <Co-CO = 121.0° (22), ∠C-C-C = 117.2° (9), ∠Cco, ClC-Cl = 118.9° (22), ∠Cccl, ClC-Cl = 122.2°(12), l(CO) = 0.039 Å(5), and l(Ccl-Ccl) = l(Co-Ccl) = l( Co-Co) = l(CC) + 0.060 Å(equalities assumed) = 0.055 Å(9). Vibrational'shortenings (shrinkages) of a few of the long non-bond distances have also been measured. 相似文献
14.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1994,50(8-9):1379-1387
The microwave spectrum of dichloroborane has been observed and the rotational constants of four isotopic species are determined as follows: A = 46911.09(7), B = 3185.937(10) and C = 2980.425(14) MHz for the normal species, A = 46747.14(8), B = 3099.543(14) and C = 2904.037(14)MHz for BHCl37Cl, A = 49302.05(24), B = 3185.536(32) and C = 2989.368(51) MHz for 10BHCl2 and A = 35153.18(9), B = 3186.026(15) and C = 2918.233(11) MHz for BDCl2. The following complete rs structure was determined: rs(BH) = 1.184(2) Å, rs(BCl) = 1.735(2) Å and ∠ ClBCl = 120.4(2)°. The hyperfine structure due to the two chlorine and one boron nuclei has been analysed. 相似文献
15.
Jan Keijsper Henk Van Der Poel Louis H. Polm Gerard Van Koten Kees Vrieze Paul F.A.B. Seignette Ronald Varenhorst Caspar Stam 《Polyhedron》1983,2(11):1111-1116
The crystal and molecular structures of c-Hex-DAB (c-hexyl-NC(H)C(H)N-c-hexyl; DAB = 1,4-diaza-1,3-butadiene) and of trans-[PdCl2(PPh3)(t-Bu-DAB)] are reported. Crystals of c-Hex-DAB are monoclinic with space group C2/c and cell constants: a = 24.70(1), b = 4.660(2), c = 12.268(3)Å, β = 107.66(4)°, Z = 4. The molecule has a flat E-s-trans-E structure with bond lengths of 1.258(3)Å for the CN double bond and 1.457(3)Å for the central CC′ bond. These bond lengths and the NC-C′ angle of 120.8(2)° indicate that the C- and N-atoms are purely sp2-hybridized and that there is little or no conjugation within the central DAB skeleton. Crystals of trans-[PdCl2(PPh3)(t-Bu-DAB)] are triclinic with space group P-1 and cell constants: a = 17.122(3), b = 18.279(3), c = 10.008(5)Å, α = 96.77(2), β = 95.29(3), γ = 109.79(2). Z = 4. The t-Bu-DAB ligand is coordinated to the metal via one lone pair only. In this 2e; σ-N coordination mode the E-s-trans-E conformation of the free DAB-ligand is still present and the bonding distances within the DAB-ligand are hardly affected. [CN: 1.261(10)Å; CC′: 1.479(10)Å (mean).] The PdN-, NC- and central CC′-bond lengths are compared with those found in other metal -R-DAB complexes. 相似文献
16.
Kenneth R. Seddon 《Journal of organometallic chemistry》1983,243(1):C17-c21
The 1/1 reaction of Et2Zn with N-t-butyliminopropanone (t-BuNC(H)C(Me)O) leads to quantitative formation of dinuclear [EtZ]2 via ethyl transfer within the unstable Et2Zn(t-BuNC(H)?C(Me)O) complex. An X-ray structure determination has shown the product to have a dinuclear structure involving a N,O-chelate bonded [Et(t-Bu)NC(H)C(Me)O]? mono-anionic ligand and a central four membered Zn2O2 ring formed by intermolecular ZnO coordination. Hydrolysis of this zinc complex gives a quantitative yield of N-t-butyl-N-ethylamino propanone, which upon reaction with Et2Zn reforms the dinuclear zinc complex. 相似文献
17.
Manabu Fujiwara Yasuhiro Nakajima Takayuki Matsushita Toshiyuki Shono 《Polyhedron》1985,4(9):1589-1594
Novel tetraaza-macrocycles with N-substituted carbamoyl groups were prepared by the reaction of 5,7,12,14-tetramethyl-1,4,8,11-tetraazacyclotetradeca-1,5,7,12-tetraene with isocyanates (RNCO, R = Ch3 and C6H5). Their copper(II) and nickel(II) complexes were characterized by magnetic susceptibilities, electronic absorption spectra, and electrochemical properties. The complexing abilities and extractabilities of the ligands for the metal ions were investigated. 相似文献
18.
C.T. Mortimer M.P. Wilkinson R.J. Puddephatt 《Journal of organometallic chemistry》1975,102(4):C43-C45
The enthalpy of the reaction: Pt(PPh3)2(CH2CH2)(cryst.) + CS2(g) → Pt(PPh3)2(CS2)(cryst.) + CH2CH2(g) has been determined as ΔH = ? 4.40 ± 2.2 kJ mol?1 from solution calorimetry, and the bond dissociation energy D(PtCS2) shown to be slightly greater than D(PtC2H4). 相似文献
19.
J.R. Dilworth H.J. de Liefde Meijer J.H. Teuben 《Journal of organometallic chemistry》1978,159(1):47-52
[Ti(η5-C5H5)Cl3] reacts with Me3SiNNPh to give [Ti(η5-C5H5)Cl2(N2Ph)], and this gives [Ti(η5-C5H5)2Cl(N2Ph)] on treatment with sodium cyclopentadienide in THF at ?80°C. [Ti(η5-C5H4R)Cl3] (R H, Me) reacts analogously with Me3SiNPR3 (PR3 PPh3, PPh2Me) to give [Ti(η5-C5H4R)Cl2(NPR3)]. Under similar conditions TiCl4 gives [TiCl4(Me3SiNPR3)]. 相似文献
20.
Depolarised Rayleigh scattering is sensitive to conjugated electronic effects. The proper effect of silicon bonded to an sp2 carbon atom in Me3SiPh and Me3SiCHCHΣ (Σ = H, Me, t-Bu, SiMe3) has been illustrated by comparison of the systems containing a Csp2M bond with the corresponding systems containing a Csp3M bond for M = C, Si. To be able to make this comparison it was necessary to study the additivity of the bond and group optical anisotropies in alkenes with Me, CMe3, SiMe3 groups by means of a more approximate model assuming axial symmetry for the CC bond but of more convenient and more general use than a more realistic model without axial symmetry. Contrary to the NSi (from monosilylamines), SiOC and SiOSi systems, silicon adjacent to an unsaturated system, causes an exaltation of the optical anisotropy which mainly results from increase of the longitudinal optical polarisability. This exaltation is consistent with electron delocalisation in an orbital obviously longer than the basic π orbital. Such an effect seems strengthened in (Me3Si)2NΣ if the donating ability of Σ increases, Σ = H, Me, t-Bu. For Me3SiCHCHSiMe3 and if the molecules Me3SiNHΣ1 (Σ1 = Me, t-Bu), (Me3Si)2NH and (Me3Si)3N are compared, a compensation is observed between the effect of the new lengthening of the π orbital and the π electronic density fall by CSi or NSi bonds. 相似文献