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1.
Compounds M(CO)23-C3H5)(L-L)(NCBH3) (L-L = dppe, M = Mo(1), W(2); L-L = bipy, M = Mo(3), W(4); L-L = en, M = Mo(5), W(6)) were prepared and characterized. The single crystal X-ray analyses of 2-6 revealed that the cyanotrihydroborate anion bonds to the metal through a nitrogen atom, the open face of the allyl group being pointed toward the two carbonyls (endo-isomer). In compounds 2, 5, and 6, the two donor atoms of the bidentate ligand occupy equatorial and axial positions, respectively. In the solid state structures of compounds 3 and 4 both nitrogen atoms of the bipy ligand occupy equatorial positions. The NMR spectroscopy reveals a fluxional behavior of compounds 1, 2, 5, and 6 in solution. Although the fluxional behavior of compounds 5 and 6 ceased at about −40 °C, that of compound 1 could not be stopped even at −90 °C. Their low temperature conformations are consistent with their solid state structures. Both the endo- and exo-isomers coexist in solution for compounds 3 and 4.  相似文献   

2.
2-Phenylaniline reacted with Pd(OAc)2 in toluene at room temperature for 24 h in a one-to-one molar ratio and with the system PdCl2, NaCl and NaOAc in a 1 (2-phenylaniline):1 (PdCl2):2 (NaCl):1 (NaOAc) molar ratio in methanol at room temperature for one week to give the dinuclear cyclopalladated compounds (μ-X)2[Pd{κ2-N2′,C1-2-(2′-NH2C6H4)C6H4}]2 [1a (X = OAc) and 1b (X = Cl)] in high yield. Moreover, the reaction between 2-phenylaniline and Pd(OAc)2 in one-to-one molar ratio in acid acetic at 60 °C for 4 h, followed by a metathesis reaction with LiBr, allowed isolation of the dinuclear cyclopalladated compound (μ-Br)2[Pd{κ2-N2′,C1-2-(2′-NH2C6H4)C6H4}]2 (1c) in moderate yield. A parallel treatment, but using monodeuterated acetic acid (DOAc) as solvent in the cyclopalladation reaction, allowed isolation of a mixture of compounds 1c, 1cd1 [Pd{κ2-N2′,C1-2-(2′-NH2C6H4)C6H4](μ-Br)2[Pd{κ2-N2′,C1-2-(2′-NH2C6H4)-3-d-C6H3] and 1cd2 (μ-Br)2[Pd{κ2-N2′,C1-2-(2′-NH2C6H4)-3-d-C6H3}]2 in moderate yield and with a deuterium content of ca. 60%. 1a and 1b reacted with pyridine and PPh3 affording the mononuclear cyclopalladated compounds [Pd{κ2-N2′,C1-2-(2′-NH2C6H4)C6H4}(X)(L)] [2a (X = OAc, L = py), 2b (X = Cl, L = py), 3a (X = OAc, L = PPh3) and 3b (X = Cl, L = PPh3)] in a yield from moderate to high. Furthermore, 1a reacted with Na(acac) · H2O to give the mononuclear cyclopalladated compound 4 [Pd{κ2-N2′,C1-2-(2′-NH2C6H4)C6H4}(acac)] in moderate yield. 1H NMR studies in CDCl3 solution of 2a, 2b, 3a, 3b and 4 showed that 2a and 3a presented an intramolecular hydrogen bond between the acetato ligand and the amino group, and were involved in a dynamic equilibrium with water present in the CDCl3 solvent; and that the enantiomeric molecules of 2b and 4 were in a fast exchange at room temperature, while they were in a slow exchange for 2a, 3a and 3b. The X-ray crystal structures of 3b and 4 were determined. 3b crystallized in the triclinic space group with a = 9.9170(10), b = 10.4750(10), c = 12.0890(10) Å, α = 98.610(10)°, β = 94.034(10)° and γ = 99.000(10)° and 4 in the monoclinic space group P21/a with a = 11.5900(10), b = 11.2730(10), c = 12.2150(10) Å, α = 90°, β = 107.6560(10)° and γ = 90°.  相似文献   

3.
The reactivity of the dimeric cyclopalladated compounds derived from biphenyl-2-ylamine (μ-X)22-N2′,C1-1-Pd-2-{(2′-NH2C6H4)C6H4}]2 [X = OAc (1), X = Cl (2)] towards unsaturated organic molecules is reported. Compound 1 reacted with carbon monoxide and tbutyl isocyanide producing phenanthridin-6(5H)-one and N-tert-butylphenanthridin-6-amine in 63% and 88% yield, respectively. Compound 2 reacted separately with diphenylacetylene and 3-hexyne, affording the mononuclear organopalladium compounds [κ2-N2″,C12-C2,C3- 1-Pd{(R-CC-R)2-2′-(2″-NH2C6H4)C6H4}Cl] [R = Ph (5), R = Et (6)] in 50-60% yield, which derived from the insertion of two alkyne molecules into the C-Pd σ bonds of 2. The crystal structure of compounds 5 and 6 has been determined. Compound 5 crystallized in the monoclinic space group P21/n with a = 13.3290(10) Å, b = 10.6610(10) Å and c = 22.3930(10) Å and β = 100.2690(10)°. Compound 6 crystallized in the triclinic space group with a = 7.271(7) Å, b = 10.038(3) Å and c = 16.012(5) Å, and α = 106.79(3)°, β = 96.25(4)° and γ = 99.62(4)°. The crystal structures of 5 and 6 have short intermolecular Pd-Cl?H-N-Pd non-conventional hydrogen bonds, which associated the molecules in chains in the first case and in dimers in the second.  相似文献   

4.
Hexakis(6-hexadecyl-2-azulenyl)benzene (1b) has been synthesized by Co2(CO)8-catalyzed cyclotrimerization reaction of bis(6-hexadecyl-2-azulenyl)acetylene (2b). The mesomorphic behaviors of 1b, 2b, and 6-hexadecyl-2-phenylazulene (3b) were studied by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and X-ray diffraction (XRD) techniques and their mesomorphic properties were compared with those of their 6-octyl derivatives 1a, 2a, and 3a. Increase of the number of carbon atoms in the peripheral side chains drops the isotropization temperatures of 1b, 2b, and 3b by 56.9 °C, 33 °C, and 23.6 °C, respectively. Additionally, the phase-transition behavior varied with increase of the number of the peripheral chains, as well as decrease of the crystalline-mesophase transition temperatures, except for compound 3b. As the results, spontaneous monodomain homeotropic molecular alignment was revealed by compound 1b in its Colhd mesophase on non-treated glass substrate, which would be attracted to the application for the device fabrication of molecular materials.  相似文献   

5.
Radical polymerizations of α-allyloxymethylstyrene (1) and copolymerizations of α-(2-phenylallyloxy)methylstyrene (2) were undertaken to acquire comprehensive understanding on polymerization behavior of these dienes and to get polymers with high thermal stability and high glass transition temperature (Tg). One of the monofunctional counterparts of 1 is a derivative of α-methylstyrene, the ceiling temperature of which is low, and the other is an allyl compound that is well-known for the low homopolymerization tendency. This means that the intermolecular propagation reactions leading to pendant uncyclized units are suppressed during the polymerization of 1 to yield highly cyclized polymers. In fact, the degree of cyclization of poly(1) obtained at 140 °C attained the value 92%. Structural studies revealed that repeat cyclic units of poly(1) consist exclusively of five-membered rings. Poly(1) was found to be stable up to 300 °C, but its Tg values were detected at around 100 °C. They are considerably lower than the targeted values which should lie between 180 and 220 °C. An additional drawback of poly(1) is its low molecular weight probably due to a degradative chain transfer. For this reason, copolymerizations of 2 with 1 and with styrene were also carried out to seek for the possibility to control the thermal properties precisely. Monomer 2 was chosen, since it has been reported in our previous work that it yields polymers with thermal stability up to 300 °C and Tg higher than 250 °C. Copolymerization of 2 with styrene afforded polymers with desired thermal properties and high molecular weight.  相似文献   

6.
The hydrolytic degradation of a series of aregic carbohydrate-based polyamides derived from l-arabinose and d-xylose is described. These polyamides are those that are fully sugar-based (PA-SuSu), those derived from aldaric acids and polyalkylene diamines (PA-mSu), and those derived from diamine sugars and polyalkylene dicarboxylic acids (PA-Sun). Their physical properties and crystal structures depend on their constitution and the configuration of the carbohydrate-based moiety. The feasibility of the hydrolysis of these polyamides was, in general, related with such structural properties. Thus, the fully sugar-based PA-SuSu were amorphous, water-soluble materials, and were hydrolysed in water at 70 °C. PA-mSu were crystalline and more resistant to hydrolysis — they were degraded at pH 2 and 70 °C [Tg(s) 60-90 °C]. PA-Sun were amorphous and highly hygroscopic materials — they were hydrolysed in water at 37 °C [Tg(s) 25-40 °C].  相似文献   

7.
Wittig reaction of 3-[4-(dimethylamino)phenyl]propanal (5) with (3-guaiazulenylmethyl)triphenylphosphonium bromide (4) in ethanol containing NaOEt at 25 °C for 24 h under argon gives the title (2E,4E)-1,3-butadiene derivative 6E in 19% isolated yield. Spectroscopic properties, crystal structure, and electrochemical behavior of the obtained new extended π-electron system 6E, compared with those of the previously reported (E)-2-[4-(dimethylamino)phenyl]-1-(3-guaiazulenyl)ethylene (12), are documented. Furthermore, reaction of 6E with 1,1,2,2-tetracyanoethylene (TCNE) in benzene at 25 °C for 24 h under argon affords a new Diels-Alder adduct 8 in 59% isolated yield. Along with spectroscopic properties of the [π4+π2] cycloaddition product 8, the crystal structure, possessing a cis-3,6-substituted 1,1,2,2-tetracyano-4-cyclohexene unit, is shown. Moreover, reaction of 6E with (E)-1,2-dicyanoethylene (DCNE) under the same reaction conditions as the above gives no product; however, this reaction in p-xylene at reflux temperature (138 °C) for four days under argon affords a new Diels-Alder adduct 9 in 54% isolated yield. Although reaction of 6E with DCNE in toluene at reflux temperature (110 °C) for four days under argon provides 9 very slightly, reaction of 6E with dimethyl acetylenedicarboxylate (DMAD) in toluene at reflux temperature for two days under argon yields a new Diels-Alder adduct 10, in 58% isolated yield, which upon oxidation with MnO2 in CH2Cl2 at 25 °C for 1 h gives 11, converting a (CH3)2N-4″ into CH3NH-4″ group, in 37% isolated yield. The crystal structure of 11 supports the molecular structure 10 possessing a partial structure cis-3,6-substituted 1,2-dimethoxycarbonyl-1,4-cyclohexadiene. The title basic studies on the above are reported in detail.  相似文献   

8.
Perfluoroindan-1-one (2) is obtained in the reaction of perfluoroindan (1) with SiO2/SbF5 at 70 °C. Compound 1 heated with SiO2/SbF5 at 130 °C and then treated with water, gives 3-hydroxy-perfluoro-3-methylphthalide (4). Ketone 2 is converted, under the action of SbF5 at 130 °C, to perfluoro-2-ethylbenzoic acid (9) and disproportionates to compound 1 and perfluoroindan-1,3-dione (3); the latter is transformed to phthalide 4 under the reaction conditions.  相似文献   

9.
The oxime of 1-acetyl adamantane 2 is added to acetylene (KOH/DMSO, 70 °C, initial acetylene pressure 13 atm, 30 min) to afford the corresponding O-vinyl oxime 5 in 80% yield. The latter upon heating (DMSO, 120 °C, 1 h) gives 2-(1-adamantyl)pyrrole 3, 1-acetyl adamantane 1, and adamantane (6:3:1 mass ratio), the yield of the pyrrole 3 being 83% (based on 1-acetyl adamantane 1 consumed). Under harsher conditions (NaOH/DMSO, 130 °C, atmospheric pressure of acetylene, 4 h) oxime 2 reacts with acetylene to furnish pyrrole 3, 1-acetyl adamantane 1, 1-vinyl adamantane 9, and adamantane (6:7:3:1 mass ratio), with the isolated yield of pyrrole 3 reaching 34%. Under pressure (NaOH/DMSO, 120 °C, initial acetylene pressure 14 atm, 1 h) the same reaction leads to 2-(1-adamantyl)-1-vinylpyrrole 4 and ketone 1 in 48% (based on consumed ketone 1) and 24% yields, respectively. The pyrrole 4 is easily deprotected to the corresponding 1H-pyrrole 3 in 77% yield by treatment (aqueous MeCN) with Hg(OAc)2 and NaBH4.  相似文献   

10.
The reactions of the trimethylsiloxychlorosilanes (Me3SiO)RR′SiCl (1a-h: R′ = Ph, 1a: R = H, 1b: R = Me, 1c: R = Et, 1d: R = iPr, 1e: R = tBu, 1f: R = Ph, 1g: R = 2,4,6-Me3C6H2 (Mes), 1h: R = 2,4,6-(Me2CH)3C6H2 (Tip); 1i: R = R′ = Mes) with lithium metal in tetrahydrofuran (THF) at −78 °C and in a mixture of THF/diethyl ether/n-pentane in a volume ratio 4:1:1 at −110 °C lead to mixtures of numerous compounds. Dependent on the substituents silyllithium derivatives (Me3SiO)RR′SiLi (2b-i), Me3SiO(RR′Si)2Li (3a-g), Me3SiRR′SiLi (4a-h), (LiO)RR′SiLi (12e, 12g-i), trisiloxanes (Me3SiO)2SiRR′ (5a-i) and trimethylsiloxydisilanes (6f, 6h, 6i) are formed. All silyllithium compounds were trapped with Me3SiCl or HMe2SiCl resulting in the following products: (Me3SiO)RR′SiSiMe2R″ (6b-i: R″ = Me, 7c-i: R″ = H), Me3SiO(RR′Si)2SiMe2R″ (8a-g: R″ = Me, 9a-g: R″ = H), Me3SiRR′SiSiMe2R″ (10a-h: R″ = Me, 11a-h: R″ = H) and (HMe2SiO)RR′SiSiMe2H (13e, 13g-i). The stability of trimethylsiloxysilyllithiums 2 depends on the substituents and on the temperature. (Me3SiO)Mes2SiLi (2i) is the most stable compound due to the high steric shielding of the silicon centre. The trimethylsiloxysilyllithiums 2a-g undergo partially self-condensation to afford the corresponding trimethylsiloxydisilanyllithiums Me3SiO(RR′Si)2Li (3a-g). (Me3)Si-O bond cleavage was observed for 2e and 2g-i. The relatively stable trimethylsiloxysilyllithiums 2f, 2g and 2i react with n-butyllithium under nucleophilic butylation to give the n-butyl-substituted silyllithiums nBuRR′SiLi (15g, 15f, 15i), which were trapped with Me3SiCl. By reaction of 2g and 2i with 2,3-dimethylbuta-1,3-diene the corresponding 1,1-diarylsilacyclopentenes 17g and 17i are obtained.X-ray studies of 17g revealed a folded silacyclopentene ring with the silicon atom located 0.5 Å above the mean plane formed by the four carbon ring atoms.  相似文献   

11.
Keun Sam Jang 《Tetrahedron》2008,64(24):5666-5671
After finding in a previous study that naphthalene and quinoline can react via electrophilic aromatic addition reaction (AdEAr), we applied this to anthracene. When anthracene was reacted with bromine in methanol in the presence of NaHCO3 and pyridine, 9,10-dihydro-9,10-dimethoxyanthracene (2) was obtained in 82% yield in the absence of substitution products or oxidative demethylation products like anthraquinone. The same reaction in ethanol produced 9,10-diethoxy-9,10-dihydroanthracene (9) in much lower yield (45%). In addition, we investigated the reactivity of addition product 2. Treatment of 2 with DDQ in benzene at 65 °C for 12 h produced 9,10-dimethoxyanthracene (3) in 62% yield, and 2 was rapidly transformed to 9-methoxyanthracene (4) in methanolic NaOH in 10 min. Moreover, the acid-catalyzed aromatization of 2 in 1-propanol at 75 °C for 10 min gave 9-n-propoxyanthracene (8) in 65% yield.  相似文献   

12.
MgMe2 (1) was found to react with 1,4-diazabicyclo[2.2.2]octane (dabco) in tetrahydrofuran (thf) yielding a binuclear complex [{MgMe2(thf)}2(μ-dabco)] (2). Furthermore, from reactions of MgMeBr with diglyme (diethylene glycol dimethyl ether), NEt3, and tmeda (N,N,N′,N′-tetramethylethylenediamine) in etheral solvents compounds MgMeBr(L), (L = diglyme (5); NEt3 (6); tmeda (7)) were obtained as highly air- and moisture-sensitive white powders. From a thf solution of 7 crystals of [MgMeBr(thf)(tmeda)] (8) were obtained. Reactions of MgMeBr with pmdta (N,N,N′,N″,N″-pentamethyldiethylenetriamine) in thf resulted in formation of [MgMeBr(pmdta)] (9) in nearly quantitative yield. On the other hand, the same reaction in diethyl ether gave MgMeBr(pmdta) · MgBr2(pmdta) (10) and [{MgMe2(pmdta)}7{MgMeBr(pmdta)}] (11) in 24% and 2% yield, respectively, as well as [MgMe2(pmdta)] (12) as colorless needle-like crystals in about 26% yield. The synthesized methylmagnesium compounds were characterized by microanalysis and 1H and 13C NMR spectroscopy. The coordination-induced shifts of the 1H and 13C nuclei of the ligands are small; the largest ones were found in the tmeda and pmdta complexes. Single-crystal X-ray diffraction analyses revealed in 2 a tetrahedral environment of the Mg atoms with a bridging dabco ligand and in 8 a trigonal-bipyramidal coordination of the Mg atom. The single-crystal X-ray diffraction analyses of [MgMe2(pmdta)] (12) and [MgBr2(pmdta)] (13) showed them to be monomeric with five-coordinate Mg atoms. The square-pyramidal coordination polyhedra are built up of three N and two C atoms in 12 and three N and two Br atoms in 13. The apical positions are occupied by methyl and bromo ligands, respectively. Temperature-dependent 1H NMR spectroscopic measurements (from 27 to −80 °C) of methylmagnesium bromide complexes MgMeBr(L) (L = thf (4); diglyme (5); NEt3 (6); tmeda (7)) in thf-d8 solutions indicated that the deeper the temperature the more the Schlenk equilibria are shifted to the dimethylmagnesium/dibromomagnesium species. Furthermore, at −80 °C the dimethylmagnesium compounds are predominant in the solutions of Grignard compounds 4-6 whereas in the case of the tmeda complex7 the equilibrium constant was roughly estimated to be 0.25. In contrast, [MgMeBr(pmdta)] (9) in thf-d8 revealed no dismutation into [MgMe2(pmdta)] (12) and [MgBr2(pmdta)] (13) even up to −100 °C. In accordance with this unexpected behavior, 1:1 mixtures of 12 and 13 were found to react in thf at room temperature yielding quantitatively the corresponding Grignard compound 9. Moreover, the structures of [MgMeBr(pmdta)] (9c), [MgMe2(pmdta)] (12c), and [MgBr2(pmdta)] (13c) were calculated on the DFT level of theory. The calculated structures 12c and 13c are in a good agreement with the experimentally observed structures 12 and 13. The equilibrium constant of the Schlenk equilibrium (2 9c ? 12c + 13c) was calculated to be Kgas = 2.0 × 10−3 (298 K) in the gas phase. Considering the solvent effects of both thf and diethyl ether using a polarized continuum model (PCM) the corresponding equilibrium constants were calculated to be Kthf = 1.2 × 10−3 and Kether = 3.2 × 10−3 (298 K), respectively.  相似文献   

13.
Reaction of pyranulose 6 with styrenes 12c or 13 and Et3N in CH2Cl2 at 25 °C afforded the [5+2] cycloadducts 14c and 15, which were hydrolyzed to give the natural products 1 and descurainin (2) in 24 and 27% overall yield, respectively. Heating pyranulose 6 with cinnamate ester 21 in the presence of 2,6-di-t-butylpyridine in CH3CN at 175 °C afforded the [5+2] cycloadduct, which was hydrolyzed to give cartorimine (3) in 13% yield.  相似文献   

14.
Two novel amphiphilic BAB-type block copolymers, ADN-PEG3400-ADN and Py-PEG3400-Py containing deep blue and bluish-green fluorescent moieties were prepared using atom transfer radical polymerization (ATRP) (where, ADN = poly(9,10-di(1-naphthalenyl)-2-vinylanthracene), Py = poly(1-vinyl pyrene) and PEG3400 = poly(ethylene glycol) with Mn = 3400 g/mol). The GPC number averaged molecular weights (MW) of the block copolymers were Mn = 9600 and 13,800 g/mol, respectively, based on polystyrene MW standards. The PEG3400 segment has a melting temperature (Tm peak) at 64–65 °C, whereas the glass transition temperatures (Tg midpoint) of the ADN and Py segments were found to be 230 °C and 193 °C, respectively, and are similar to their respective homopolymers indicating complete microphase segregration. The photoluminescence (PL) emission of the copolymers ADN-PEG3400-ADN exhibited two maxima at 423.5 nm and 441.5 nm while Py-PEG3400-Py has a maximum at 488.5 nm. Both copolymers form individual spherical micelles with diameter from 30 to 90 nm for Py-PEG3400-Py and 40–160 nm for ADN-PEG3400-ADN. The micelles, however, transform into cross-linked pearl-necklace-like aggregates at polymer concentrations above 1000 ppm, which may be attributed to the physical cross-linking between adjacent spherical micelles caused by the PEG3400 segments.  相似文献   

15.
The DNA binding of polypyridyl (pp) (η5-C5Me5)RhIII complexes of the types [(η5-C5Me5)RhCl(pp)](CF3SO3) (2-6) (pp = bpy, phen, dpq, dppz, dppn), [(η5-C5Me5)Rh{(Me2N)2CS}(pp)](CF3SO3)2 (7-9) (pp = dpq, dppz, dppn) and [(η5-C5Me5)Rh(L)(pp)](CF3SO3) (10) (L = C6H5S) and (11) (L = C10H7S) has been studied by UV/Vis spectroscopy, circular dichroismus and viscosity measurements. Complexes 3-11 are cytotoxic towards the human MCF-7 breast and HT-29 colon cancer cell lines and exhibit IC50 values in the range 0.56-10.7 μM. Stable intercalative binding into CT-DNA is indicated for the dpq and dppz complexes by large increases ΔTm of 6-12 °C in the DNA thermal denaturation temperature for r = [complex]/[DNA] = 0.1 and by induced CD bands and large viscosity increases. In contrast, significant DNA lengthening is not observed after incubation of the biopolymer with the dppn complexes 2 and 9 at molar ratios of r < 0.08. Pronounced hypochromic shifts for the π-π transitions of the dppn ligands in the range 320-425 nm indicate the possible presence of surface stacking. The in vitro cytotoxicities of the chloro complexes 4-6 and the (Me2N)2CS complexes 7-9 are dependent on the size of the polypyridyl ligand with IC50 values decreasing in the order dpq > dppz > dppn. For instance, IC50 values of 5.3, 1.5 and 0.91 μM were determined for 7-9 against MCF-7 cells. Rapid Cl/H2O exchange leads the formation of aqua dications for 4-6, whose levels of cellular uptake and cytotoxicities are similar to those established for 7-9. Intramolecular interactions between the aromatic thiolate and dppz ligands of 10 and 11 prevent significant DNA intercalation. X-ray structural determinations have been performed for 2-7 and 11.  相似文献   

16.
Methylation of α-disubstituted cyclopentanone 1 with Me3Al in CH2Cl2 at 0 °C for 30 min gave diastereoselectively a mixture of (1R*,2S*)-2 and (1R*,2R*)-2 in a 96:4 ratio and 83% total yield. When the same methylation was carried out at 0 °C for 1 h and then at room temperature for 120 h, a diastereomeric mixture of (1R*,2S*)-2 and (1R*,2R*)-2 was obtained in a 12:88 ratio and in 88% total yield. The stereochemistry of the two diastereomers was determined by the results of acetalization of their diol derivatives 3 and 5. Isomerization between the Me2Al-alkoxides of (1R*,2S*)-2 and (1R*,2R*)-2 and its possible mechanism were investigated by HPLC analysis of the methylation reaction process at 0 °C for 1 h and then at room temperature for 56 h and also by their mutual epimerization reactions.  相似文献   

17.
Mononuclear compounds M(CO)23-C3H5)(en)(X) (X = Br, M = Mo(1), W(2); X = N3, M = Mo(3), W(4); X = CN, M = Mo(5), W(6)) and cyanide-bridged bimetallic compounds [(en)(η3-C3H5)(CO)2M(μ-CN)M(CO)23-C3H5)(en)]Br (M = Mo (7), W(8)) were prepared and characterized. These compounds are fluxional and display broad unresolved proton NMR signals at room temperature. Compounds 1-6 were characterized by NMR spectroscopy at −60 °C, which revealed isomers in solution. The major isomers of 1-4 adopt an asymmetric endo-conformation, while those of 5 and 6 were both found to possess a symmetric endo-conformation. The single crystal X-ray structures of 1-6 are consistent with the structures of the major isomer in solution at low temperature. In contrast to mononuclear terminal cyanide compounds 5 and 6, cyanide-bridged compounds 7 and 8 were found to adopt the asymmetric endo-conformation in the solid state.  相似文献   

18.
Platinum complexes of the type [Pt(cis-1,4-DACH)(L)2]X, where cis-1,4-DACH = cis-1,4-diaminocyclohexane; L = adenine (ade) (1), hypoxanthine (hyp) (2), 9-methylguanine (9-megua) (3), cytosine (cyt) (4), or 1-methylcytosine (1-mecyt) (5); and X = SO4 or Cl2 groups, were synthesized and characterized by elemental analysis and by 1H, 13C, and 195Pt nuclear magnetic resonance spectroscopy. The crystals of [Pt(cis-1,4-DACH)(9-megua)2]SO4[9-megua-H]2SO4 (3) and [Pt(cis-1,4-DACH)(1-mecyt)2]Cl2 · 6H2O (5) were also subjected to single-crystal X-ray diffraction. The base/PtN4 coordination plane dihedral angles were 74.55° and 85.61° in complex 3 and 78.12° and 81.80° in complex 5. The platinum had distorted square planar geometry in both complexes; the two adjacent corners were occupied by the two nitrogen atoms of cis-1,4-DACH, and the other two corners were occupied by the two N7 atoms of 9-megua in complex 3 and the two N3 atoms of 1-mecyt in complex 5. The cis-1,4-DACH, which has a unique twist-boat configuration, formed a seven-member chelating ring with platinum, which led to considerable strain during bidentate cis-1,4-DACH binding. Cations of both complexes 3 and 5 adopted C2 molecular symmetry. These adducts were the models for the intrastand cross-links that were relevant to the binding of the Pt(II) antitumor drugs to DNA.  相似文献   

19.
Coupling reaction of polychloromethanes CH4−nCln (n = 2-4) with HSiCl3 in the presence of tetrabutylphosphonium chloride (Bu4PCl) as a catalyst occurred at temperatures ranging from 30 °C to 150 °C. The reactivity of polychloromethanes increases as the number of chlorine-substituents on the carbon increases. In the reactions of CCl4 with HSiCl3, a variety of coupling products such as bis(chlorosilyl)methanes CH2(SiCl3)(SiXCl2) [X = Cl (1a), H (1b)], (chlorosilyl)trichloromthanes Cl3CSiXCl2 [X = Cl (2a), H (2b)], and (chlorosilyl)dichloromthanes Cl2HCSiXCl2 [X = Cl (3a), H (3b)] were obtained along with reductive dechlorination products such as CHCl3 and CH2Cl2 depending on the reaction temperature. In the reaction of CCl4, 2a is formed at the initial stage of the coupling reaction and converted to give CHCl3 at low temperature of 30 °C, to give 1a, 3a, and CHCl3 at 60 °C, and to afford 1a as major product and CH2Cl2 in competition above 100 °C. Si-H bond containing silylmethanes can be formed by the H-Cl exchange reaction with HSiCl3. Reaction of CHCl3 with HSiCl3 took placed at 80 °C to give three compounds 1a, 3a, and CH2Cl2, and finally 3a was converted to give 1a and CH2Cl2 at longer reaction time. While the condition for the reaction of CH2Cl2 with HSiCl3 required a much higher temperature of 150 °C. Under the optimized conditions for synthesizing bis(chlorosilyl)methanes 1a,b, a mixture of 1a and 1b were obtained as major products in 65% (1a:1b = 64:1) and 47% (42:5) yields from the reaction of CCl4 and CHCl3 at 100 °C for 8 h, respectively, and in 41% (34:7) yield from that of CH2Cl2 at 170 °C for 12 h. In the Si-C coupling reaction of polychloromethanes with HSiCl3, it seems likely that a trichlorosilyl anion generated from the reaction of HSiCl3 with Bu4PCl is an important key intermediate.  相似文献   

20.
The work in this paper reports syntheses, molecular and supramolecular structures, electrochemistry and magnetic properties of two diphenoxo-bridged dinickel(II) compounds [NiII2L(N3)2(H2O)2]·CH3CN (1) and [NiII2L(N3)2(H2O)] (2), where H2L is the tetraimino diphenolate macrocyclic ligand, obtained on [2 + 2] condensation of 4-methyl-2,6-diformylphenol and 2,2′-dimethyl-1,3-diaminopropane. Brown colored compound 1 and green colored compound 2 are produced from the same reaction mixture as a function of temperature; 1 is formed from the reaction mixture in acetonitrile at low temperature (ca. 5 °C), while 2 is formed on heating the reaction mixture in acetonitrile. Crystals of compounds 1 and 2 are monoclinic (space group P21/c) and orthorhombic (space group P212121), respectively. Analyses of the crystal packing of the crystalline phases reveal that two-dimensional topologies are resulted in both 1 and 2 due to hydrogen bonding interactions. Variable-temperature (2-300 K) magnetic susceptibility measurements of the two compounds reveal that the metal centers in both the complexes are coupled by moderate antiferromagnetic interactions with J values (= -2JS1·S2) −18.8 and −34.2 cm−1 for 1 and 2, respectively. Electrochemical analyses of 2 reveal that this compound exhibits two-step reduction couples at E½ = −977 and −1155 mV.  相似文献   

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