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1.
The transition 4A 2 → 2E of Co 2+ has been investigated in [N(CH 3) 4] 2CoCl 4 using optical absorption and magnetic circular dichroism. Three groups of lines with 274 cm −1 progressions were observed. The structure of the spectra indicates a J-T interaction in the 2E state with strong depression of the frequency of the J-T active mode. The ground-state splitting is 7.2 cm −1. 相似文献
2.
Gaussian-2 ab initio calculations were performed to examine the six modes of unimolecular dissociation of cis-CH 3CHSH + (1 +), trans-CH 3CHSH + (2 +), and CH 3SCH 2+ (3 +): 1 +→CH 3++ trans-HCSH (1); 1 +→CH 3+ trans-HCSH + (2); 1 +→CH 4+HCS + (3); 1 +→H 2+ c-CH 2CHS + (4); 2 +→H 2+CH 3CS + (5); and 3 +→H 2+ c-CH 2CHS + (6). Reactions (1) and (2) have endothermicities of 584 and 496 kJ mol −1, respectively. Loss of CH 4 from 1 + (reaction (3)) proceeds through proton transfer from the S atom to the methyl group, followed by cleavage of the C–C bond. The reaction pathway has an energy barrier of 292 kJ mol −1 and a transition state with a wide spectrum of nonclassical structures. Reaction (4) has a critical energy of 296 kJ mol −1 and it also proceeds through the same proton transfer step as reaction (3), followed by elimination of H 2. Formation of CH 3CS + from 2 + (reaction (5)) by loss of H 2 proceeds through protonation of the methine (C H) group, followed by dissociation of the H 2 moiety. Its energy barrier is 276 kJ mol −1. On both the MP2/6-31G* and QCISD/6-31G* potential-energy surfaces, the H 2 1,1-elimination from 3 + (reaction (6)) proceeds via a nonclassical intermediate resembling c-CH 3SCH 2+ and has a critical energy of 269 kJ mol −1. 相似文献
3.
Sn(CH 3) 2Cl 2 exerts its antitumor activity in a specific way. Unlike anticancer cis-Pt(NH 3) 2Cl 2 drug which binds strongly to the nitrogen atoms of DNA bases, Sn(CH 3) 2Cl 2 shows no major affinity towards base binding. Thus, the mechanism of action by which tinorganometallic compounds exert antitumor activity would be different from that of the cisplatin drug. The aim of this study was to examine the binding of Sn(CH 3) 2Cl 2 with calf thymus DNA and yeast RNA in aqueous solutions at pH 7.1–6.6 with constant concentrations of DNA and RNA and various molar ratios of Sn(CH 3) 2Cl 2/DNA (phosphate) and Sn(CH 3) 2Cl 2/RNA of 1/40, 1/20, 1/10, 1/5. Fourier transform infrared (FTIR) and UV–visible difference spectroscopic methods were used to determine the Sn(CH 3) 2Cl 2 binding mode, binding constant, sequence selectivity and structural variations of Sn(CH 3) 2Cl 2/DNA and Sn(CH 3) 2Cl 2/RNA complexes in aqueous solution. Sn(CH 3) 2Cl 2 hydrolyzes in water to give Sn(CH 3) 2(OH) 2 and [Sn(CH 3) 2(OH)(H 2O) n] + species. Spectroscopic evidence showed that interaction occurred mainly through (CH 3) 2Sn(IV) hydroxide and polynucleotide backbone phosphate group with overall binding constant of K(Sn(CH 3) 2Cl 2–DNA)=1.47×10 5 M −1 and K(Sn(CH 3) 2Cl 2–RNA)=7.33×10 5 M −1. Sn(CH 3) 2Cl 2 induced no biopolymer conformational changes with DNA remaining in the B-family structure and RNA in A-conformation upon drug complexation. 相似文献
4.
The reactions of the half-sandwich molybdenum(III) complexes CpMo(η 4-C 4H 4R 2)(CH 3) 2, where Cp=η 5-C 5H 5 and R=H or CH 3, with equimolar amounts of B(C 6F 5) 3 have been investigated in toluene. EPR monitoring shows the formation of an addition product which does not readily react with Lewis bases such as ethylene, pyridine, or PMe 3. The analysis of the EPR properties and the X-ray structure of a decomposition product obtained from dichloromethane, [CpMo(η 4-C 4H 6)(μ-Cl)(μ-CH 2)(O)MoCp][CH 3B(C 6F 5) 3], indicate that the borane attack has occurred at the methyl position. 相似文献
5.
The Ca( 1D 2, 3P J) + CH 3 → CaI(A,B) + CH 3 reactions system has been studied by measuring its chemiluminescence under beam-gas conditions. Absolute values of the state-to-state reaction cross-sections were determined at low collision energy
. In addition, the electronic branching ratio and product energy disposal have been determined for each metastable reaction. The major changed observed in the chemiluminescence when comparing the Ca( 1D 2) reaction versus that of Ca( 3P J) is the total yield associated with the former reaction. To the best of our spectral resolution neither the electronic branching ratio e.g. CaI(A)/CaI(B) nor the internal CaI energy disposal change significantly as the metastable Ca( 1D 2)/Ca( 3P J) ratio is varied. In spite of the fact that the Ca( 3P J) reaction is less exoergic, the CaI product appears with a higher fraction of internal energy than that of Ca( 1D 2) reaction. Thus, the fraction of the total energy appearing in CaI internal energy amounts to 57.5% in the Ca( 3P J) reaction while it is 19.3% only for the Ca( 1D 2) reaction. This difference is discussed in the light of a distinct mechanism associated with the attack of the excited Ca atom into the C---I bond. No significant chemiluminescence yield was found for the energetically open CaCH *3 channels. The product chemiluminescence polarization was also measured as a function of the metastable concentration. A significant degree of polarization was found depending upon the specific electronic excitation. The analysis of the polarization emission associated to the parallel CaI(X 2Σ+ ← B 2Σ+) emission led into a strong polarization of the product rotational angular momentum. The comparison of the product rotational alignment for the kinematically identical Ca(1D2, 3PJ, 1P1) + CH3 → CaI* (B2Σ+) + CH3 reaction system showed that the CaI rotational polarization diminishes in the 3PJ → 1D2 → 1P1 sequence, e.g. as the reaction exothermicity increases. In addition the degree of polarization associated with other emission bands as for example CaI(X 2Σ+ ← A 2Π1/2) indicates the presence of a parallel transition which was been interpreted as mixing of Hund's case (a) and (c) appropriate for this heavy CaI diatom produced with a high rotational excitation. 相似文献
6.
Addition of 1,4-dithiols to dichloromethane solutions of [PtCl 2(P-P)] (P-P = (PPh 3) 2, Ph 2P(CH 2) 3PPh 2, Phd 2P(CH 2) 4PPh 2; 1,4-dithiols = HS(CH 2) 4SH, (−)DIOSH 2 (2,3- O-isopropylidene-1,4-dithiol-l-threitol), BINASH 2 (1,1′-dinaphthalene-2,2′-dithiol)) in the presence of NEt 3 yielded the mononuclear complexes [Pt(1,4-dithiolato)(P-P)]. Related palladium(II) complexes [Pd(dithiolato)(P-P)] (P-P=Ph 2P(CH 2) 3PPh 2, Ph 2P(CH 2) 4PPh 2; dithiolato = −S(CH 2) 4S −, (−)-DIOS) were prepared by the same method. The structure of [Pt((−)DIOS)(PPh 3) 2] and [Pd(S(CH 2) 4S)(Ph 2P(CH 2) 3PPh 2)] complexes was determined by X-ray diffraction methods. Pt—dithiolato—SnC1 2 systems are active in the hydroformylation of styrene. At 100 atm and 125°C [Pt(dithiolate)(P-P)]/SnCl 2 (Pt:Sn = 20) systems provided aldehyde conversion up to 80%. 相似文献
7.
A series of novel arylantimony(V) triphenylgermanylpropionates with the formula (Ph 3GeCHR 1CHR 2CO 2) nSbAr (5−n) (R 1=H, Ph; R 2=H, CH 3; n=1, 2) were synthesized and characterized by elemental analysis, IR, 1H-NMR, 13C-NMR and mass spectroscopy. The crystal structures of Ph 3GeCH(Ph)CH 2CO 2SbPh 4 and [Ph 3GeCH 2CH(CH 3)CO 2] 2Sb(4-ClC 6H 4) 3 were determined by X-ray diffraction. The in vitro antitumor activities of some selected compounds against five cancer cells are reported. 相似文献
8.
Reaction of ansa-cyclopentadienyl pyrrolyl ligand (C 5H 5)CH 2(2-C 4H 3NH) (2) with Ti(NMe 2) 4 affords bis(dimethylamido)titanium complex [(η 5-C 5H 4)CH 2(2-C 4H 3N)]Ti(NMe 2) 2 (3) via amine elimination. A cyclopentadiene ligand with two pendant pyrrolyl arms, a mixture of 1,3- and 1,4-{CH 2(2-C 4H 3NH)} 2C 5H 4 (4), undergoes an analogous reaction with Ti(NMe 2) 4 to give [1,3-{CH 2(2-C 4H 3N)} 2(η 5-C 5H 3)]Ti(NMe 2) (5). Molecular structures of 3 and 5 have been determined by single crystal X-ray diffraction studies. 相似文献
9.
Reaction of the optically active primary amine (S)-(—)--methylbenzylamine with trimethylaluminium in heptane affords the crystalline organoaluminium dimer (S)-(—)-(S)-(—)-[(C 6H 5)CH(CH 3)NHA1(CH 3) 2] 2. Isolated as large, colourless, extremely air-sensitive prismatic crystals, the title compound crystallizes in the orthorhombic space group P2 12 12 1 with unit cell parameters a = 8.406(3), b = 15.505(4), c = 17.547(5) Å, V = 2287 Å 3 and p = 1.03 g cm −3 for Z = 4. Least-squares refinement based on 1477 observed reflections converged at R = 0.056, R w = 0.058. Methane was eliminated during the course of the reaction due to cleavage of A1---C and N---H bonds resulting in an asymmetric A1 2N 2 fragment at the core of the organoaluminium dimer. The mean A1---C bond distance in the dimethylaluminium units is 1.930(8), while the mean A1---N bond distance is 1.950(5) Å. Specific rotation ([] D25 in CH 2C1 2)of the dimer is determined to be - 20.6°. 相似文献
10.
The electron donating water soluble phosphines, P{(CH 2) nC 6H 4- p-SO 3Na} 3, n = 1, 2, 3 and 6, react rapidly with Co 2(CO) 8 under two phase reaction conditions to yield the disproportionation products, [Co(CO) 3(P{(CH 2) nC 6H 4- p-SO 3Na 3} 2] [Co(CO) 4]. Selective precipitation yields the formally zwitterionic complex anions as the sodium salt, [Co(CO) 3(P{(CH 2) nC 6H 4- p-SO 3} 3) 2] 5−. The anions can be used as precursors to water soluble cobalt hydroformylation catalysts under two phase and supported aqueous phase conditions. The tendency to form alcohol products is low with these complexes. The behavior of the catalysts is consistent with an active species that remains water soluble during the reaction and is not leached into the nonaqueous phase. 相似文献
11.
The interaction of [(η 5-C 5H 4Bu t) 2YbCl · LiCl] with one equivalent of Li[(CH 2) (CH 2)PPh 2] in tetrahydrofuran gave [Ph 2PMe 2][(η 5-C 5H 4Bu t) 2Li] (1) and [(η 5-C 5H 4Bu t) 2Yb(Cl)CH 2P(Me)Ph 2] (2) in 10% and 30% yields, respectively. 1 could also be prepared in 70% yield from the reaction of [Ph 2PMe 2][CF 3SO 3] with two equivalents of (C 5H 4Bu t)Li. Both compounds have been fully characterized by analytical, spectroscopic and X-ray diffraction methods. The solid state structure of 1 reveals a sandwich structure for the [(η 5-C 5H 4Bu t) 2Li] − anion. 相似文献
12.
Polarized absorption spectra of Ba(MnO 4) 2·3H 2O/Ba(ClO 4) 2·3H 2O mixed single crystals are reported at 4.2°K. Previous 1T 2 → 1A 1 assignments for the 5200 Å and 3000 Å absorption bands of MnO 4− are substantiated; further support is provided for the 1T 1 → 1A 1 assignment of the 3600 Å absorption band of MnO 4−. The site-splitting of the 5200 Å 1T 2 state is E( 1E)− E( 1A) ≈ −150 cm −1; that of the 3000 Å 1T 2 state is E( 1E)− E( 1A) ≈ 300 cm −1. A significant e vibronic intensity component is observed in the 5200 Å 1T 2 state. 相似文献
13.
Hafnium β-diketonatochlorides HfCl 2(thd) 2 (1), HfCl(thd) 3 (2) as well as β-diketonato-silylamide and/or siloxide derivatives of 1 namely Hf(thd) 2[N(SiMe 3) 2] 2 (3), Hf(thd) 2(OSiMe 3) 2 (4) and Hf(thd) 2(OSi tBuMe 2) 2 (5) (thd = 2,2,6,6-tetramethyl-3,5-heptanedionate) were synthesized and characterized by elemental analysis, FT-IR, 1H NMR and TGA. 2 and 5 were also characterized by single-crystal X-ray diffraction. The siloxide ligands are in cis position for 5 and exert a strong trans effect. The new volatile compounds were tested as single-source precursors for the deposition of HfSi xO y films by pulsed liquid injection MOCVD on Si(1 0 0) and R plane sapphire. The as-deposited at 600–800 °C films were essentially amorphous, Hf-rich (Hf/Hf + Si = 0.7–0.85) and smooth. 相似文献
14.
Transamination reactions utilizing the compound mercuric bis(trimethylsilyl)amide, Hg{N(SiMe 3) 2} 2, in tetrahydrofuran (THF), and the metals Na, Mg, Ca, Sr, Ba and Al have been investigated. Thus the THF solvated compounds Na[N(SiMe 3) 2]·THF and M[N(SiMe 3) 2] 2·2THF, M = Mg, Ca, Sr and Ba (1–4), have been prepared. The X-ray crystal structures of 1 and the related manganese compound Mn[N(SiMe 3) 2] 2·2THF (5) are reported. Interaction of the silylamides, 2–4, with a range of crown ethers apparently proceeded with elimination of silylamine, (Me 3Si) 2NH, and novel ring opening of the crown ethers, generating species containing a donor alkoxide ligand with a vinyl ether function, presumably, ---O(CH 2CH 2O) nCH=CH 2 ( n = 3−5). The silylamides 2–4 were also cleanly converted to the corresponding alkoxides (from 1H NMR data) in reactions with stoichiometric quantities of 3-ethyl-3-pentanol. 相似文献
15.
The ruthenium(II) complex Ru(CO) 2(NH 2(NH 2CH 2C 6H 5) 2(Si(C 6H 5)(CH 3) 2)I has been prepared by the reaction of Ru(CO) 4(Si(C 6H 5)(CH 3) 2)I with benzylamine. Two-dimensional homonuclear 1H NMR experiments examine the scalar coupling of the enantiotopic amino and methylene protons of the benzylamine ligand. X-ray analysis of Ru(CO) 2(NH 2CH 2C 6H 5) 2(Si(C 6H 5)(CH 3) 2)I·1/3C 5H 12 (triclinic; P
; a = 14.266(4), b = 15.748(5), c = 20.082(6) Å; = 94.38(3), β = 96.30(2), γ = 101.52(2)°) indicates three crystallographically unique complexes form a clathrate with a pentane guest. 相似文献
16.
The P-functional organotin dichloride [Ph 2P(CH 2) 3] 2SnCl 2 (3) is synthesized by reaction of Ph 2P(CH 2) 3MgCl with SnCl 4 independently of the molar ratio of the starting compounds. The corresponding organotin trichlorides Ph 2P(CH 2) nSnCl 2R (4: n=2, R=Cl; 5: n=3, R=Cl; 6: n=3, R=Me) are formed in a cleavage reaction of Ph 2P(CH 2) nSnCy 3 ( n=2, 3) with SnCl 4 or MeSnCl 3, respectively. The main features of the crystal structures of 3–6 are both intra- and intermolecular PSn coordinations and the existence of intermolecular Sn---ClSn bridges. For further characterization of the title compounds, the adducts 4(Ph 3PO) 2 (7) and 5(Ph 3PO) (8), as well as the P-oxides and P-sulfides of 3–6 (9–15), are synthesized. The results of crystal structure analyses of 7, 11, 12, and 14 are reported. The structures of 9–15 are characterized by intramolecular P=XSn interactions (X=O, S). A first insight into the structural behavior of the compounds 3–15 in solution is discussed on the basis of multinuclear NMR data. 相似文献
17.
Six new cluster derivatives [Rh 2Co 2(CO) 6(μ-CO) 4(μ 4,η 2-HCCR)] (R=FeCp 2 1, CH 2OH 2, (CH 3O)C 10H 6CH(CH 3)COOCH 2CCH 3) and [RhCo 3(CO) 6(μ-CO) 4(μ 4,η 2-HCCR)] (R=FeCp 2 4, CH 2OH 5, (CH 3O)C 10H 6CH(CH 3)COOCH 2CCH 6) were obtained by the reactions of [Rh 2Co 2(CO) 12] and [RhCo 3(CO) 12] with substituted 1-alkyne ligands HCCR [R=FeCp 2 7, CH 2OH 8, (CH 3O)C 10H 6CH(CH 3) COOCH 2CCH 9] in n-hexane at room temperature, respectively. Alkynes insert into the Co---Co bond of the tetranuclear clusters to give butterfly clusters. [Rh 2Co 2(CO) 6(μ-CO) 4(μ 4,η 2-HCCFeCp 2)] (1) was characterized by a single-crystal X-ray diffraction analysis. Reactions of 1, 2 with 7, 8 and ambient pressure of carbon monoxide at 25 °C gave two known cluster complexes [Co 2(CO) 6(μ 2, η 2-HCCR)] (R=FeCp 2 10, CH 2OH 11), respectively. All clusters were characterized by element analysis, IR and 1H-NMR spectroscopy. 相似文献
18.
Thermal displacement of coordinated nitriles RCN (R = CH 3, C 2H 5 or n-C 3H 7) in [C 5H 5Fe(L 2)(NCR)]X complexes (L 2 = P(OCH 3) 3) 2, (P(OC 6H 5) 3) 2 or (C 6H 5) 2PC 2H 4P(C 6H 5) 2 (DPPE)) by E(CH 3) 2 affords high yields of [C 5H 5Fe(L 2)(E(CH 3) 2)]X compounds (E = S, Se and Te; X = BF 4 or PF 6). Spectroscopic data and ligand displacement reactions are presented and discussed together with related observations on [C 5H 5Fe(CO) 2(E(CH 3) 2)]BF 4 compounds. The molecular structure of [C 5H 5Fe(P(OCH 3) 3) 2(S(CH 3) 2)]PF 6 was determined by a single-crystal X-ray diffraction study: monoclinic, space group P2 1/ n- C52h (No. 14) with a = 8.4064(12), b = 11.183(2), c = 50.726(8) Å, β = 90.672(13)° and Z = 8 molecules per unit cell. The coordination sphere of the iron atom is pseudo-tetrahedral with an Fe---S bond distance of 2.238 Å. 相似文献
19.
The 60-electron tetrahedral clusters W 2Ir 2(μ-L)(CO) 8(η 5-C 5H 4Me) 2 [L=dppe (2), dppf (3)] have been prepared from reaction between W 2Ir 2(CO) 10(η 5-C 5H 4Me) 2 (1) and the corresponding diphosphine in 52 and 66% yields, respectively. A structural study of 2 reveals that three edges of a WIr 2 face are spanned by bridging carbonyls, that the iridium-ligated diphosphine coordinates diaxially and that the tungsten-bound methylcyclopentadienyls coordinate axially and apically with respect to the plane of bridging carbonyls. A structural study of 3 reveals that the dppf ligand bridges an Ir---Ir bond which is also spanned by a bridging carbonyl; tungsten-ligated methylcyclopentadienyl ligands and terminal carbonyls result in electronic asymmetry (17e and 19e iridium atoms) in the electron-precise cluster. Both clusters show two reversible one-electron oxidation processes and an irreversible two-electron reduction; the dppf-containing cluster 3 has a further, irreversible, one-electron oxidation process. UV–vis-NIR spectroelectrochemical studies of the 2→2 +→2 2+ progression reveal the appearance of a low-energy transition on oxidation to 2 + which persists on further oxidation to 2 2+. 相似文献
20.
The syntheses and structural determination of Nd III and Er III complexes with nitrilotriacetic acid (nta) were reported in this paper. Their crystal and molecular structures and compositions were determined by single-crystal X-ray structure analyses and elemental analyses, respectively. The crystal of K 3[Nd III(nta) 2(H 2O)]·6H 2O complex belongs to monoclinic crystal system and C2/ c space group. The crystal data are as follows: a=1.5490(11) nm, b=1.3028(9) nm, c=2.6237(18) nm, β=96.803(10)°, V=5.257(6) nm 3, Z=8, M=763.89, Dc=1.930 g cm −3, μ=2.535 mm −1 and F(000)=3048. The final R1 and wR1 are 0.0390 and 0.0703 for 4501 ( I>2σ( I)) unique reflections, R2 and wR2 are 0.0758 and 0.0783 for all 10474 reflections, respectively. The Nd IIIN 2O 7 part in the [Nd III(nta) 2(H 2O)] 3− complex anion has a pseudo-monocapped square antiprismatic nine-coordinate structure in which the eight coordinate atoms (two N and six O) are from the two nta ligands and a water molecule coordinate to the central Nd III ion directly. The crystal of the K 3[Er III(nta) 2(H 2O)]·5H 2O complex also belongs to monoclinic crystal system and C2/ c space group. The crystal data are as follows: a=1.5343(5) nm, b=1.2880(4) nm, c=2.6154(8) nm, b=96.033(5)°, V=5.140(3) nm 3, Z=8, M=768.89, Dc=1.987 g cm −3, μ=3.833 mm −1 and F(000)=3032. The final R1 and wR1 are 0.0321 and 0.0671 for 4445 ( I>2σ( I)) unique reflections, R2 and wR2 are 0.0432 and 0.0699 for all 10207 reflections, respectively. The Er IIIN 2O 7 part in the [Er III(nta) 2(H 2O)] 3− complex anion has the same structure as Nd IIIN 2O 7 part in which the eight coordinate atoms (two N and six O) are from the two nta ligands and a water molecule coordinate to the central Nd III ion directly. 相似文献
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