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1.
ESR.-spectra are reported for the radical anion and the radical cation of benzo[b]-biphenylene (III). Comparison of the proton coupling constants (a) for III · ? and III · ⊕ with π-spin populations (?μ), calculated by the McLachlan procedure, permits a lower limit of 0.77 to be set for the parameter κ = β′/β where β′ represents a reduced value of the HMO integral for the two essentially single bonds linking the benzene with the naphthalene π-system. The differences in the a values for III · ? and III · ⊕ are substantially larger than those generally found for the two corresponding radical ions of alternant, purely benzenoid hydrocarbons, but they closely parallel the analogous differences observed for the radical anion and the radical cation of biphenylene.  相似文献   

2.
{[CdCl(2,2′-bipy)2(H2O)]+·[Cd(3-O?-2,7-NDS)(2,2′-bipy)2]?·3H2O} (1) and {[Cd(phen)3]2+·2[Cd(3-O?-2,7-NDS)(phen)2]?·8.5H2O} (2) (3-OH-2,7-NDS?=?3-hydroxy-2,7-naphthalenedisulfonate, phen?=?1,10-phenanthroline, and 2,2′-bipy?=?2,2′-bipydine) were prepared and characterized by X-ray single-crystal diffraction. Compound 1 contains a discrete coordination cation [CdCl(2,2′-bipy)2(H2O)]+ and a coordination anion [Cd(3-O?-2,7-NDS)(2,2′-bipy)2]?; 2 contains a discrete coordination cation [Cd(phen)3]2+ and two coordination anions [Cd(3-O?-2,7-NDS)(phen)2]?. There are numerous weak interactions among the coordination cation, coordination anion, and free water molecules, such as O–H?···?O hydrogen bonds, π?···?π stacking, and Cl??···?π interactions in 1 and π?···?π stacking and C–H?···?π interactions in 2. The cations and anions as building blocks are connected to construct different 3-D supramolecular architectures via weak intermolecular interactions. Particularly, the capsule structure of 1 was observed.  相似文献   

3.
The radical anion and the radical cation of azuleno[1,2,3-cd]phenalene (III) have been investigated by ESR. spectroscopy, along with the radical anion of 2-phenylazulene (IV). Also studied has been the neutral radical obtained by one-electron reduction of cyclohepta[cd]phenalenium-cation (VI). Assignment of the proton coupling constants for the radical ions III. ·?, III ·⊕ and IV·⊕, and the radical VI · is supported by comparison with the ESR. spectra of specifically deuteriated derivatives III-d5 ·?, III-d5 ·⊕, IV-d2 ·? and VI-d1′. The experimental results are in full accord with qualitative topological arguments and predictions of HMO models. Whereas the radical anion III ·? exhibits α-spin distribution similar to that of IV ·?the corresponding radical cation III ·⊕ and the neutral radical VI · are related in this respect to phenalenyl (V·). It is noteworthy that oxidation of III by conc. H2SO4 yields a paramagnetic species (IIIa ·⊕) which has a similar – but not an identical – structure as the radical cation III ·⊕ produced from III with AlCl3 in CH3NO2.  相似文献   

4.
The title compounds, C14H12N+·CH3O4S?, (I), and C15H14N+·CH3O4S?, (II), respectively, crystallize with the planar 10‐methylacridinium or 9,10‐di­methyl­acridinium cations arranged in layers, parallel to the twofold axis in (I) and perpendicular to the 21 axis in (II). Adjacent cations in both compounds are packed in a `head‐to‐tail' manner. The methyl sulfate anion only exhibits planar symmetry in (II). The cations and anions are linked through C—H?O interactions involving three O atoms of the anion, six acridine H atoms and the CH3 group on the N atom in (I), and the four O atoms of the anion, three acridine H atoms and the carbon‐bound CH3 group in (II). The methyl sulfate anions are oriented differently in the two compounds relative to the cations, being nearly perpendicular in (I) but parallel in (II). Electrostatic interaction between the ions and the network of C—H?O interactions leads to relatively compact crystal lattices in both structures.  相似文献   

5.
The resonance parameters σ R + of substituents Y in radical cations YD [where D is a π- or n-type center, and Y = MMe3, CH2MMe3 (M = Si, Ge, Sn), C(SiMe3)3] depend on the nature of both Y and D. Using radical cations YD (Y = CH2SiMe3, SnMe3) as examples, it was found that the two conjugation parameters, constants σ R + of substituents Y and perturbation energy calculated by the modified molecular orbital perturbation method, are linearly related to each other. The energies of donor and acceptor components of the overall resonance effect of CH2SiMe3 and SnMe3 with respect to radical cation centers D were estimated for the first time. The donor energy constituent in YD is considerably greater than in neutral DY molecules.  相似文献   

6.
It was shown that trimethylene oxide (oxetane) radical cations were converted at 77 K into either distonic radical cations ·CH2CH2CH=OH+ or 2-oxetanyl radicals, depending on the freonic matrix used, by the action of light at λ = 546 nm and trimethylene sulfide radical cations transformed into distonic radical cations CH2CHSH+CH 2 · under 436-nm irradiation. The quantum yields of the photochemical reactions were determined. Quantum-chemical calculations on the structure and HFC constants of the radical cations and possible paramagnetic products of their transformation were performed. The reasons behind the observed difference in reactivity between the radical cations under the action of light are discussed.  相似文献   

7.
To enable a comparison between a C—H…X hydrogen bond and a halogen bond, the structures of two fluorous‐substituted pyridinium iodide salts have been determined. 4‐[(2,2‐Difluoroethoxy)methyl]pyridinium iodide, C8H10F2NO+·I, (1), has a –CH2OCH2CF2H substituent at the para position of the pyridinium ring and 4‐[(3‐chloro‐2,2,3,3‐tetrafluoropropoxy)methyl]pyridinium iodide, C9H9ClF4NO+·I, (2), has a –CH2OCH2CF2CF2Cl substituent at the para position of the pyridinium ring. In salt (1), the iodide anion is involved in one N—H…I and three C—H…I hydrogen bonds, which, together with C—H…F hydrogen bonds, link the cations and anions into a three‐dimensional network. For salt (2), the iodide anion is involved in one N—H…I hydrogen bond, two C—H…I hydrogen bonds and one C—Cl…I halogen bond; additional C—H…F and C—F…F interactions link the cations and anions into a three‐dimensional arrangement.  相似文献   

8.
Two new salts, [2-NaMePy]2[Ni(i-mnt)2] (1) and [2-NaMe-4-MePy]2[Ni(i-mnt)2] (2) ([2-NaMePy]+ = 1-(2′-naphthylmethyl)pyridinium, [2-NaMe-4-MePy]+ = 1-(2′-naphthylmethyl)-4-methylpyridinium and i-mnt2? = iso-maleonitriledithiolate), have been prepared and characterized by elemental analyses, UV, IR, molar conductivity, and single crystal X-ray diffraction. The anions in 1 form a 1-D chain through short C ··· N interactions between the anions, while the cations in 2 stack a 1-D column via C–H ··· π and π ··· π stacking interactions between the cations. The effect of weak intramolecular interactions such as C–H ··· N, C–H ··· S, C–H ··· Ni hydrogen bonds, and π ··· π stacking interactions between the cations and the anions further generate a 3-D network structure. The change of the molecular topology of the countercation when the 4-substituted group in the pyridine ring is changed from H atom to CH3 group results in different crystal system, space group, and the stacking mode of the cations and anions of 1 and 2.  相似文献   

9.
By X-ray diffraction the crystal and molecular structure of iodoprotatrane (tris(2-hydroxyethyl)ammonium iodide I[HN(CH2CH2OH)3]+ (IP) at 120 K and 293 K is determined. The IP cation, as in all protatranes, has the endo conformation. The N-H bond is surrounded by three CH2CH2OH groups. The stability of this configuration is explained by the intramolecular trifurcated inductive interaction with three oxygen atoms through the space of the nitrogen atom. In the IP crystal packing, each iodine anion is linked by three strong OH...I (2.63 Å) and three weak I...H (3.13 Å) hydrogen bonds with six cations from the CH2N group. This indicates a greater nucleophilicity of the iodine atom.  相似文献   

10.
《Tetrahedron》1986,42(22):6225-6234
Ab initio molecular orbital calculations on the distonic radical cations CH2(CH2)nN+H3 and their conventional isomers CH3(CH2)nNH2+ (n = 0,1, 2 and 3) indicate a preference in each case for the distonic isomer. The energy difference appears to converge with increasing n towards a limit which is close to the energy difference between the component systems CH3·H2+CH3+NH3 (representing the distonic isomer) and CH3CH3+CH3NH2+ (representing the conventional isomer). The generality of this result is assessed by using results for the component systems CH3·Y+CH3X+H and CH3YH+CH3X+. (or CH3YH+. + CH3X) to predict the relative energies of the distonic ions ·Y(CH2)nX+H and their conventional isomers HY(CH2)nX+. (X = NH2, OH, F, PH2, SH, Cl; Y = CH2, NH, O) and testing the predictions through explicit calculations for systems with n = 0,1 and 2. Although the predictions based on component systems are often close to the results of direct calculations, there are substantial discrepancies in a number of cases; the reasons for such discrepancies are discussed. Caution must be exercised in applying this and related predictive schemes. For the systems examined in the present study, the conventional radical cation is predicted in most cases to lie lower in energy than its distonic isomer. It is found that the more important factors contributing to a preference for distonic over conventional radical cations are the presence in the system of a group(X) with high proton affinity and the absence of a group (X, Y or perturbed (C—C) with low ionization energy.  相似文献   

11.
Matrix isolation ESR study showed that the ligated HCCO? ion was decomposed into H+ and ·COO? radical anion through CTTM process at λ = 254 nm, by contrast, ·CH3 radical and CO2 were produced from CH3COO? ligand. In order to explain the photo- and related reactions in the liquid solution, a proposal is made for a cyclic scheme conjugated with the photo-decomposition of the complex. The cycle consists of three steps; photo-reduction of H+ by Eu2+, radical alternation from ·H to ·COO?, and oxidation of ·COO? by Eu3+.  相似文献   

12.
The neutral thorium complex Th(NCSe)4(OP(NMe2)3)4 and homoleptic octa(isoselenocyanato)uranate anion U(NCSe)84– in (Pr4N)4U(NCSe)8·2CFCl3 ( 1 ) were synthesised and structurally characterised. (Pr4N)4U(NCSe)8·2CFCl3 contains the UIV anion U(NCSe)84– 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)84– 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.  相似文献   

13.
The ionic complexes simultaneously containing negatively charged coordination structures of metal phthalocyanines and fullerene anions, viz., {MnIIPc(CH3CH2S?) x ·(I?)1?x }·(C60 ·?)· ·(PMDAE+)2·C6H4Cl2 (PMDAE is N,N,N′,N′,N′-pentamethyldiaminoethane, x = 0.87, 1) and {ZnIIPc(CH3CH2S?)y·(I?)1?y }2·(C60 ?)2·(PMDAE+)4·(C6H4Cl2) (y = 0.5, 2) were synthesized. The both compounds were obtained as single crystals, which made it possible to study their crystal structures. In complex 1, the fullerene radical anions form honeycomb-like layers in which each fullerene has three neighbors with center-to-center interfullerene distances of 10.13–10.29 Å. Rather long distances between the C60 ·? radical anions results in the retention of monomeric C60 ·? in this complex down to the temperature of 110(2) K. In complex 2, fullerenes form dimers (C60 ?)2 bonded by one C-C bond. The dimers are packed in corrugated honeycomb-like layers with interfullerene center-to-center distances of 9.90–10.11 Å. Manganese(II) and zinc(II) phthalocyanines coordinate iodide and ethanethiolate anions to the central metal atom to form unusual negatively charged coordination structures MIIPc(An?) (An? is anion) packed in dimers {MIIPc(An?)}2 with a short distance between the phthalocyanine planes (3.14 Å in 1 and 3.27 Å in 2). The pthalocyanine dimers also form layers with the PMDAE+ cations, and these layers alternate with the fullerene layers. The packing of spherical fullerenes with planar phthalocyanine molecules is attained by the insertion of fullerenes between the phenylene groups of phthalocyanines. The π-π-interactions of the porphyrin macrocycle with five- or six-membered fullerene rings are characteristic of the earlier studied ionic porphyrin and fullerene complexes. Such interactions are not observed for ionic complexes 1 and 2.  相似文献   

14.
15.
Abstract

Self-assembly of ZnX2 (X?=?Cl, Br, and I) with 2,7-bis(isonicotinoyloxy)naphthalene (L) in a mixture of ethanol and dichloromethane yields 1-D zigzag chains of [ZnX2L·2CH2Cl2]n composition. The 1-D chains form an ensemble constituting hydrophobic suprachannels of 4.0–4.4?×?4.4–5.0 Å2 with repeat units of ZnL for [ZnCl2L] and [ZnBr2L], and those of 5.2?×?12.0 Å2 with repeat units of Zn2L2 for [ZnI2L] in the appropriate arrays via C–H···π and π···π interactions. The most interesting feature is that alcohol molecules are not incorporated into the haloalkane-philic channels. That is, the channels discriminate haloalkanes from alcohols. Furthermore, the exchange of solvate molecules in a crystalline state indicates that the unique channels show different absorptions of haloalkanes such as CH2Cl2, CH2Br2, CH2I2, CHCl3, 1,2-dichloroethane, and 1,2-dibromoethane.  相似文献   

16.
In the title compound, C4H12N22+·2C8H7O3?·2CH4O, the cations lie across centres of inversion and are disordered over two orientations with equal occupancy; there are equal numbers of (R)‐ and (S)‐mandelate anions present (mandelate is α‐hydroxy­benzene­acetate). The anions and the neutral water mol­ecules are linked by O—H?O hydrogen bonds [O?O 2.658 (3) and 2.682 (3) Å, and O—H?O 176 and 166°] into deeply folded zigzag chains. Each orientation of the cation forms two symmetry‐related two‐centre N—H?O hydrogen bonds [N?O 2.588 (4) and 2.678 (4) Å, and N—H?O 177 and 171°] and two asymmetric, but planar, three‐centre N—H?(O)2 hydrogen bonds [N?O 2.686 (4)–3.137 (4) Å and N—H?O 137–147°], and by means of these the cations link the anion/water chains into bilayers.  相似文献   

17.
The interaction of Cat2B10H10 (Cat = Ph4P+, Ph4As+) with acetic acid has been studied. Disubstituted closo-decaborate derivatives with a bidentately bound acetate group, Cat[2,6(9)-B10H8>(O)2CCH3], or two monodentate acetate groups, Cat2[2,7(8)-B10H8(OC(O)CH3)2], have been isolated (Cat = Ph4P+, Ph4As+). Hydrolysis of these compounds has led to the position isomers of the [B10H8(OC(O)CH3)(OH)]2? anion with the hydroxo and acetate groups in the 2,6(9)- and 2,7(8)-positions. The structures of {Pb(Bipy)2[2,6(9)-B10H8(OC(O)CH3)(OH)]}2 · 3H2O, (Ph4As)2[2,6(9)-B10H8(OC(O)CH3)(OH)] · 0.4C2H5OH · 0.25H2O, and (Ph4As)2[2,7(8)-B10H8(OC(O)CH3)(OH)], as well as of the product of the reaction of the B10H 10 2? anion with formic acid (Ph4P)2[2-B10H9OC(O)H] · CH3CN, have been determined by X-ray crystallography.  相似文献   

18.
Traditional π-covalent interactions have been proved in the non-metal halogen bond adducts formed by chloride and halogenated triphenylamine-based radical cations. In this study, we have rationally designed two metal-involving halogen bond adducts with π-covalency property, such as [L1-Pd···I-PTZ]+ (i.e., 1) and [L2-Pd···I-PTZ]+ (i.e., 2), in which the square-planar palladium complexes serve as halogen bond acceptor and 3,7-diiodo-10H-phenothiazine radical cation (i.e., [I-PTZ]•+) acts as halogen bond donor. Noncovalent interaction analysis and quantum theory of atoms in molecules analysis revealed that there are notable halogen bond interactions along the Pd···I direction without genuine chemical bond formed in both designed adducts. Energy decomposition analysis together with natural orbital for chemical valence calculations were performed to gain insight into their bonding nature, which demonstrated the presence of remarkable π-covalent interactions and σ-covalent interactions in both 1 and 2. We therefore proposed a new strategy for building the metal-involving halogen bonds with π-covalency property, which will help the further development of new types of halogen bonds.  相似文献   

19.
Absolute rate constants for the addition of the 2-hydroxy-2-propyl radical to 18 substituted alkenes (CH2 = CXY) were determined at (296 ± 1) K in 2-propanol by time-resolved electronspin-resonance spectroscopy. With alkene substitution the rate constants vary by more than 6 orders of magnitude. For 3,3-dimethyl-but-1-ene the temperature dependence is given by log k/M?1 · s?1 = 6.4 minus;; 19.1/Θ where Θ = 2.303 RT in kJ/mol?1. As shown by a good correlation with the alkene electron affinities, log k296/M?1 · s?1 = 6.46 + 1.71 · EA/eV (r = 0.930), 2-hydroxy-2-propyl is a very nucleophilic radical, and its addition rates are highly governed by polar effects. © 1993 John Wiley & Sons, Inc.  相似文献   

20.
Preparation und Characterization of Phthalocyanine-π-Cation-Radicals of H+, Mg2+, and Cu2+ The preparation of phthalocyanine-π-cation-radicals (Pc(?1)) of H+, Mg2+, Cu2+ is described. MgClPc(?1) and Cu(NO3)Pc(?1) · HNO3 are isolated as stoichiometrically pure, stable redbrown solids. Contrary to the phthalocyanines(?2) (Pc(?2)) these are very soluble with redviolet colour in organic solvents in the presence of R? COOH (R ? H, CF3, CCl3). The electronic absorption absorption spectra (UV-VIS) are remarkably solvent-dependent. This solvent effect is due to a reversible radical association. Monomeric radical species exist in nonpolar (CH2Cl2), dimeric in polar solvents (CH3NO2, C2H5OH). The UV-VIS, infrared (IR), and resonance-raman (RR) spectra of MgClPc(?1) and Cu(NO3)Pc(?1) · HNO3 are discussed and compared with the analogoues spectra of MgPc(?2) · 2 H2O and MgPc(?2) · HCl. Although there are only minor differences in the chemical composition and the electronic structure the spectroscopic data vary significantly for every complex. Especially the IR spectrum is suitable for a quick demonstration of the π-cation-radicals. The diagnostic bands are at ca. 1350 and 1450 cm?1.  相似文献   

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