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1.
P. M. Toporowski J. Roovers 《Journal of polymer science. Part A, Polymer chemistry》1986,24(11):3009-3019
A series of eighteen-arm regular star polybutadienes with molecular weights between 9.9 × 104 and 1.9 × 106 were prepared and characterized. Evidence is presented for the expanded configuration of the large eighteen-arm stars in a θ solvent. The intrinsic viscosities of the eighteen-arm stars gave g′ = [η]/[η]l = 0.284 in dioxane at 27°C (θ solvent) and 0.225 in toluene at 35°C (good solvent). The linear viscoelastic properties of the melts were also determined. The plateau modulus, GN°, is the same as for linear polybutadiene. The zero-shear viscosities (η0) and the longest relaxation times (Tmax) increase exponentially with the arm molecular weight Ma and are identical to those of four-arm polybutadienes with the same Ma. The zero-shear recoverable compliance (Je°) increases linearly with molecular weight. v′ in Je°GN° = v′Na, where Na is the number of entanglements per arm, is 0.95 slightly larger than 0.66 for four-arm polybutadienes. Similarly, g2 is higher than calculated from the Rouse–Ham theory. 相似文献
2.
V. Jíov J. Jan
a M. Kolínský 《Journal of polymer science. Part A, Polymer chemistry》1977,15(3):533-536
A sample of high molecular weight poly(vinyl chloride) (PVC) was fractionated by classical precipitation fractionation and gel-permeation chromatography (GPC) on a preparative scale. The fractions thus obtained were characterized by light scattering, viscometry, and by the GPC method. The measured weight-average molecular weights M?w, intrinsic viscosity [η], and polydispersity index M?w/M?n values were used for the determination of the Mark-Houwink equation, [η] = KMa, for PVC in cyclohexanone (CHX) at 25°C valid for molecular weights from 100,000 to 625,000. 相似文献
3.
C. V. Goebel P. efelín J. Stehlí
ek J. ebenda 《Journal of polymer science. Part A, Polymer chemistry》1972,10(5):1411-1427
For unfractionated anionic polymers, the following relationship between the osmometric molecular weight and intrinsic viscosity is valid: M?n = 13200[η]1.115 (cresol), or M?n = 13000[η]1.021 (93.8% H2SO4). A comparison of the osmometric and viscometric data with the number of endgroups of a polymer confirmed the finding that under certain conditions, moderately branched molecules can be formed; the above parameters depend on the type of the activator used. 相似文献
4.
Tsukasa Sakai 《Journal of Polymer Science.Polymer Physics》1968,6(8):1535-1549
The Huggins constant k′ in the expression for the viscosity of dilute nonelectrolytic polymer solutions, η = η(1 + [η] c + k′[η]2c2 + …), is calculated. For polymers in the theta condition, k′ is estimated to be 0.5 < kθ′ ≤ 0.7. For good solvent systems, the Peterson-Fixman theory of k′ has been modified; the equilibrium radial distribution function in the original theory is replaced with a parametric distribution for interpenetrating macromolecules in the shear force field. Comparison of the modified theory with experimental k′ for polystyrenes and poly(methyl methacrylates) of different molecular weights in various solvents shows good agreement. An empirical equation which correlates the Huggins constant k′ and the viscosity expansion factor αη for polymers has been found to coincide well with the modified theory. 相似文献
5.
V. M. Chernyshev A. N. Sokolov D. A. Khoroshkin V. A. Taranushich 《Russian Journal of Organic Chemistry》2008,44(5):715-722
The hydrogenation of 2-amino-5-R-7-R′-4,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidines with NaBH4 led to the formation of 2-amino-5-R-7-R′-4,5,6,7-tetrahydro-1,2,4-triazolo[1,5-a]pyrimidines. Acylation, sulfonylation, and alkylation of these compounds depending on conditions and the reagent character occur at the amino group, atoms N3 or N4. The treatment with alkali of 2-amino-3-benzyl-5-R-7-R′-4,5,6,7-tetrahydro-1,2,4-triazolo-[1,5-a]pyrimidinium bromide resulted in 2-amino-3-benzyl-5-R-7-R′-3,5,6,7-tetrahydro-1,2,4-triazolo[1,5-a]-pyrimidine, similar reaction of 2-acetamido-3-benzyl-5-R-7-R′-4,5,6,7-tetrahydro-1,2,4-triazolo[1,5-a]-pyrimidinium bromide gave a mesoionic product of a hydrogen elimination from the amide nitrogen atom. 相似文献
6.
Four‐Membered Heterometallacyclic d0 and d1 Complexes of Group 4 Metallocenes with Amidato Ligands
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Dr. Martin Haehnel Jacqueline B. Priebe Jacky C.‐H. Yim Dr. Anke Spannenberg Prof. Dr. Angelika Brückner Prof. Dr. Laurel L. Schafer Prof. Dr. Uwe Rosenthal 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(25):7752-7758
A study of the coordination chemistry of different amidato ligands [(R)N?C(Ph)O] (R=Ph, 2,6‐diisopropylphenyl (Dipp)) at Group 4 metallocenes is presented. The heterometallacyclic complexes [Cp2M(Cl){κ2‐N,O‐(R)N?C(Ph)O}] M=Zr, R=Dipp ( 1 a ), Ph ( 1 b ); M=Hf, R=Ph ( 2 )) were synthesized by reaction of [Cp2MCl2] with the corresponding deprotonated amides. Complex 1 a was also prepared by direct deprotonation of the amide with Schwartz reagent [Cp2Zr(H)Cl]. Salt metathesis reaction of [Cp2Zr(H)Cl] with deprotonated amide [(Dipp)N?C(Ph)O] gave the zirconocene hydrido complex [Cp2M(H){κ2‐N,O‐(Dipp)N?C(Ph)O}] ( 3 ). Reaction of 1 a with Mg did not result in the desired Zr(III) complex but in formation of Mg complex [(py)3Mg(Cl) {κ2‐N,O‐(Dipp)N?C(Ph)O}] ( 4 ; py=pyridine). The paramagnetic complexes [Cp′2Ti{κ2‐N,O‐(R)N?C(Ph)O}] (Cp′=Cp, R=Ph ( 7 a ); Cp′=Cp, R=Dipp ( 7 b ); Cp′=Cp*, R=Ph ( 8 )) were prepared by the reaction of the known titanocene alkyne complexes [Cp2′Ti(η2‐Me3SiC2SiMe3)] (Cp′=Cp ( 5 ), Cp′=Cp* ( 6 )) with the corresponding amides. Complexes 1 a , 2 , 3 , 4 , 7 a , 7 b , and 8 were characterized by X‐ray crystallography. The structure and bonding of complexes 7 a and 8 were also characterized by EPR spectroscopy. 相似文献
7.
《Journal of heterocyclic chemistry》2018,55(6):1450-1478
Novel [1,2,4]triazole derivatives were synthesized via various synthetic pathways. Among which were different substituted [1,2,4]triazole analogues that were synthesized, in addition to various fused [1,2,4]triazolo[1,5‐a]pyrimidine derivatives, [1,2,4]triazolo[1,5‐a][1,3,5]triazines, and [1,2,4]triazolo[5,1‐c][1,2,4]triazines. Besides, benzo[h][1,2,4]triazolo[5,1‐b]quinazolines, [1,2,4]triazolo‐[5,1‐b]quinazoline, [1,2,4]triazolo[1,5‐a]quinazoline and [1,2,4]triazolo[5,1‐d][1,2,3,5]tetrazine derivatives were also synthesized. The newly synthesized compounds were evaluated for their in vitro anticancer activity against liver cancer HepG2 and breast cancer MCF7 cell lines compared with the reference drug doxorubicin. Compounds 4 , 7 , 15 , 17 , 28 , 34 , and 47 were found to exert promising anticancer activity against HepG2 cell line showing IC50 values ranging from 17.69 to 25.4 μM/L, while compounds 7 , 14a , 17 , 28 , and 34 showed significant activity against MCF7 cell line with IC50 values ranging from 17.69 to 27.09 μM/L. 相似文献
8.
A. R. Shultz A. L. Bridgman E. M. Hadsell C. R. McCullough 《Journal of Polymer Science.Polymer Physics》1972,10(2):273-282
Ten unfractionated poly(2,6-diphenyl-1,4-phenylene oxide) samples were examined by gel permeation chromatography (GPC) and intrinsic viscosity [η] at 50°C in benzene, by intrinsic viscosity at 25°C in chloroform, and by light scattering at 30°C in chloroform. The GPC column was calibrated with ten narrow-distribution polystyrenes and styrene monomer to yield a “universal” relation of log ([η]M) versus elution volume. GPC-average molecular weights, defined as M?gpc = \documentclass{article}\pagestyle{empty}\begin{document}$\Sigma w_i [\eta ]_i M_i /\Sigma w_i [\eta ]_i$\end{document}, wi denoting the weight fraction of polymer of molecular weight Mi, were computed from the GPC and [η] data on the polyethers. The M?GPC were then compared with the weight-average M?w from light scattering. The intrinsic viscosity (dl/g) versus molecular weight relations for the unfractionated poly(2,6-diphenyl-1,4-phenylene oxides) determined over the molecular weight range 14,000 ≤ M?w ≤ 1,145,000 are log [η] = ?3.494 + 0.609 log M?w (chloroform, 25°C) and log [η] = ?3.705 + 0.638 log M?w (benzene, 50°C). The M?w(GPC)/M?n(GPC) ratios for the polymers in the molecular weight range 14,000 ≤ M?w ≤ 123,000 approximate 1.5 according to computer integrations of the GPC curves with the use of the “universal” calibration and the measured log [η] versus log M?w relation. The higher molecular weight polymers (326,000 ≤ M?w ≤ 1,145,000) show slightly broadened distributions. 相似文献
9.
Deprotonation, methylation, and air oxidation of polycyclic arenes coordinated to chromium(0), (η6-arene)Cr(CO)3, produced ring-methylated products with high selectivity and in good yield. This procedure gave 3-methylbenz[a]anthracene from (η6-benz[a]anthracene)Cr(CO)3, 3-methylphenanthrene from (η6-phenanthrene)Cr(CO)3, 2-acetyl-6-methylphenanthrene from (η6?2-acetylphenanthrene)Cr(CO)3, and 3,7,12-trimethylbenz[a]anthracene from (η6?7,12-dimethylbenz[a]anthracene)Cr(CO)3. 相似文献
10.
Diimido, Imido Oxo, Dioxo, and Imido Alkylidene Halfsandwich Compounds via Selective Hydrolysis and α—H Abstraction in Molybdenum(VI) and Tungsten(VI) Organyl Complexes Organometal imides [(η5‐C5R5)M(NR′)2Ph] (M = Mo, W, R = H, Me, R′ = Mes, tBu) 4 — 8 can be prepared by reaction of halfsandwich complexes [(η5‐C5R5)M(NR′)2Cl] with phenyl lithium in good yields. Starting from phenyl complexes 4 — 8 as well as from previously described methyl compounds [(η5‐C5Me5)M(NtBu)2Me] (M = Mo, W), reactions with aqueous HCl lead to imido(oxo) methyl and phenyl complexes [(η5‐C5Me5)M(NtBu)(O)(R)] M = Mo, R = Me ( 9 ), Ph ( 10 ); M = W, R = Ph ( 11 ) and dioxo complexes [(η5‐C5Me5)M(O)2(CH3)] M = Mo ( 12 ), M = W ( 13 ). Hydrolysis of organometal imides with conservation of M‐C σ and π bonds is in fact an attractive synthetic alternative for the synthesis of organometal oxides with respect to known strategies based on the oxidative decarbonylation of low valent alkyl CO and NO complexes. In a similar manner, protolysis of [(η5‐C5H5)W(NtBu)2(CH3)] and [(η5‐C5Me5)Mo(NtBu)2(CH3)] by HCl gas leads to [(η5‐C5H5)W(NtBu)Cl2(CH3)] 14 und [(η5‐C5Me5)Mo(NtBu)Cl2(CH3)] 15 with conservation of the M‐C bonds. The inert character of the relatively non‐polar M‐C σ bonds with respect to protolysis offers a strategy for the synthesis of methyl chloro complexes not accessible by partial methylation of [(η5‐C5R5)M(NR′)Cl3] with MeLi. As pure substances only trimethyl compounds [(η5‐C5R5)M(NtBu)(CH3)3] 16 ‐ 18 , M = Mo, W, R = H, Me, are isolated. Imido(benzylidene) complexes [(η5‐C5Me5)M(NtBu)(CHPh)(CH2Ph)] M = Mo ( 19 ), W ( 20 ) are generated by alkylation of [(η5‐C5Me5)M(NtBu)Cl3] with PhCH2MgCl via α‐H abstraction. Based on nmr data a trend of decreasing donor capability of the ligands [NtBu]2— > [O]2— > [CHR]2— ? 2 [CH3]— > 2 [Cl]— emerges. 相似文献
11.
P. Cinquina D. Cam E. Tampellini L. L. Chapoy 《Journal of Polymer Science.Polymer Physics》1993,31(12):1809-1817
Solution characterization of the thermotropic liquid–crystalline copolyester synthesized from terephthalic acid, phenyl hydroquinone, and (1-phenylethyl) hydroquinone (2 : 1 : 1) has been performed. Viscometry, size exclusion chromatography, and light scattering have been carried out under the optimal conditions found for measurement: 85°C in a 50/50 mixture by weight of phenol/1,2,4-trichlorobenzene. The absolute weight-average molecular weight from light-scattering measurements served for calibration of indirect methods of charac-terization (e.g., the limiting viscosity number [η] is related to the molecular weight by [η] = 5.10 × 10?4 Mw0.72), and the molecular weight per unit chain length, $ \bar M_L * $, from light scattering and size exclusion chromatography (SEC) is found to be 28 Å?1, consistent with theoretical expectations. The calculated persistence length q is 28 Å. Moreover, the meth-odology of SEC characterization enables the kinetics of solid-state postpolymerization of this liquid-crystalline copolyester to be studied. © 1993 John Wiley & Sons, Inc. 相似文献
12.
Reactivity of Liquid Ammonia Solutions of the Zintl Phase K12Sn17 towards Mesitylcopper(I) and Phosphinegold(I) Chloride
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Dr. Christian B. Benda Dr. Markus Waibel Dr. Tobias Köchner Prof. Dr. Thomas F. Fässler 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(50):16738-16746
To gain more insight into the reactivity of intermetalloid clusters, the reactivity of the Zintl phase K12Sn17, which contains [Sn4]4? and [Sn9]4? cluster anions, was investigated. The reaction of K12Sn17 with gold(I) phosphine chloride yielded K7[(η2‐Sn4)Au(η2‐Sn4)](NH3)16 ( 1 ) and K17[(η2‐Sn4)Au(η2‐Sn4)]2(NH2)3(NH3)52 ( 2 ), which both contain the anion [(Sn4)Au(Sn4)]7? ( 1 a ) that consists of two [Sn4]4? tetrahedra linked through a central gold atom. Anion 1 a represents the first binary Au?Sn polyanion. From this reaction, the solvate structure [K([2.2.2]crypt)]3K[Sn9](NH3)18 ( 3 ; [2.2.2]crypt=4,7,13,16,21,24‐hexaoxa‐1,10‐diazabicyclo[8.8.8]hexacosane) was also obtained. In the analogous reaction of mesitylcopper with K12Sn17 in the presence of [18]crown‐6 in liquid ammonia, crystals of the composition [K([18]crown‐6)]2[K([18]crown‐6)(MesH)(NH3)][Cu@Sn9](thf) ( 4 ) were isolated ([18]crown‐6=1,4,7,10,13,16‐hexaoxacyclooctadiene, MesH=mesitylene, thf=tetrahydrofuran) and featured a [Cu@Sn9]3? cluster. A similar reaction with [2.2.2]crypt as a sequestering agent led to the formation of crystals of [K[2.2.2]crypt][MesCuMes] ( 5 ). The cocrystallization of mesitylene in 4 and the presence of [MesCuMes]? ( 5 a ) in 5 provides strong evidence that the migration of a bare Cu atom into an Sn9 anion takes place through the release of a Mes? anion from mesitylcopper, which either migrates to another mesitylcopper to form 5 a or is subsequently protonated to give MesH. 相似文献
13.
Experimental evidence concerning the dependence of the intrinsic viscosity [η] on molecular weight M in the low molecular weight range (from oligomers to M = 5 × 104) has been collected in a variety of solvents for about ten polymers, i.e., polyethylene, poly(ethylene oxide), poly(propylene oxide), polydimethylsiloxane, polyisobutylene, poly(vinylacetate), poly(methyl methacrylate), polystyrene, poly-α-methylstyrene, and some cellulose derivatives. In theta solvents, the constancy of the ratio [η]Θ/M0.5 extends down to values of M much lower than those predicted by current hydrodynamic theories. In good solvents, and on decreasing M, the polymers examined, with the exception of polyethylene and some cellulose derivatives, show a decrease in the exponent a of the Mark-Houwink equation [η] = KMa. This upward curvature gives rise to the existence of a more or less extended linear region where the equation [η] = K0M0.5 is obeyed. Below the linear range, i.e., for even shorter chains, the exponent a can increase, i.e., polydimethylsiloxane, or decrease below 0.5, i.e., poly(ethylene oxide), depending on the particular chain properties. These different dependences have been discussed in terms of: (a) variations of thermodynamic interactions with molecular weight; (b) variations of conformational characteristics (as for instance the ratio) 〈r02/nl2〉, where 〈r02〉 is the unperturbed mean square end-to-end distance and n is the number of bonds each of length l; (c) hydrodynamic properties of short chains. 相似文献
14.
《Journal of Coordination Chemistry》2012,65(16):1807-1811
The complexes [M(CO)4(η2-H2L)] [M?=?Cr; 1, Mo; 2, W; 3] have been synthesized by photochemical reactions of VIB metal carbonyls [M(CO)6] [M?=?Cr,?Mo,?W] with N,N′-bis(salicylidene)-1,2-bis-(o-aminophenoxy)ethane (H2L) in THF and characterized by elemental analyses, FTIR, 1H?NMR and mass spectra. The H2L ligand is coordinated to the central metal as a bidentate ligand via the central azomethine nitrogen atoms in 1–3. 相似文献
15.
By choosing suitable approximations to Bueche's function, it is possible to calculate the viscosity versus shear stress for log-normal molecularly distributed linear polymers. For bulk polymers the mixing rules M?w, M?w, M?z are considered. For values of η/η0 > 0.1 and heterogeneities with M?w/M?n > 1.5 the result obtained with any mixing rule is η/η0 = erfc [(1/delta;) log (M0Qh/aK)], where a = π2/6pRT and where the δ and K values are dependent on the heterogeneity ratio Q = M?w/M?n and on the type of mixing rule; on the other hand, the h value is independent of the heterogeneity, but depends on the mixing rule. Most experimental data should fit the M?w mixing rule as one would expect from the zero shear stress mixing rule. Experimental data are compared with the theoretical results. 相似文献
16.
Coordination Chemistry of P-rich Phosphanes and Silylphosphanes. XVI [1] Reactions of [g2-{P–PtBu2}Pt(PPh3)2] and [g2-{P–PtBu2}Pt(dppe)] with Metal Carbonyls. Formation of [g2-{(CO)5M · PPtBu2}Pt(PPh3)2] (M = Cr, W) and [g2-{(CO)5Cr · PPtBu2}Pt(dppe)] [η2-{P–PtBu2}Pt(PPh3)2] 4 reacts with M(CO)5 · THF (M = Cr, W) by adding the M(CO)5 group to the phosphinophosphinidene ligand yielding [η2-{(CO)5Cr · PPtBu2}Pt(PPh3)2] 1 , or [η2-{(CO)5W · PPtBu2}Pt(PPh3)2] 2 , respectively. Similarly, [η2-{P–PtBu2}Pt(dppe)] 5 yields [η2-{(CO)5Cr · PPtBu2}Pt(dppe)] 3 . Compounds 1 , 2 and 3 are characterized by their 1H- and 31P-NMR spectra, for 2 and 3 also crystal structure determinations were performed. 2 crystallizes in the monoclinic space group P21/n (no. 14) with a = 1422.7(1) pm, b = 1509.3(1) pm, c = 2262.4(2) pm, β = 103.669(9)°. 3 crystallizes in the triclinic space group P1 (no. 2) with a = 1064.55(9) pm, b = 1149.9(1) pm, c = 1693.2(1) pm, α = 88.020(8)°, β = 72.524(7)°, γ = 85.850(8)°. 相似文献
17.
V. A. Tartakovsky A. E. Frumkin A. M. Churakov Yu. A. Strelenko 《Russian Chemical Bulletin》2005,54(3):719-725
Thermal cyclization of 3-R-5-chloro-1,2,4-triazoles (R = Cl, Ph) afforded 2,6,10-tri-R- tris[1,2,4]triazolo[1,5-a:1′,5′c:1″,5″-e][1,3,5]triazines 5 (R = Ph) and 7 (R = Cl). These compounds are first representatives of this class of heterocycles, whose structures were unambiguously established. Treatment of these compounds with nucleophiles (H2O/NaOH, NH3) results in the triazine ring opening to give compounds consisting of three 1,2,4-triazole rings linked in a chain. For example, treatment of cyclic compound 5 with aqueous alkali affords 3-phenyl-1-3-phenyl-1-(3-phenyl-1H-1,2,4-triazol-5-yl)-1,2,4-triazol-5-yl-1H-1,2,4-triazol-5-one. Treatment of 3,7,11-triphenyltris[1,2,4]triazolo[4,3-a:4′,3′c:4″,3″-e][1,3,5]triazine (2) with HCl/SbCl5 leads to the triazine ring opening giving rise to 5-(3-chloro-5-phenyl-1,2,4-triazol-4-yl)-3-phenyl-4-(5-phenyl-1H-1,2,4-triazol-3-yl)-1,2,4-triazole. Thermal cyclization of the latter produces 3,7,10-triphenyltris[1,2,4]triazolo[1,5-a:4′,3′c:4″,3″-e][1,3,5]triazine (13). Thermolysis of both cyclic compound 2 and cyclic compound 13 is accompanied by the Dimroth rearrangement to yield 3,6,10-triphenyl-tris[1,2,4]triazolo[1,5-a:1′, 5′-c:4″,3″-e][1,3,5]triazine (14). Compounds 13 and 14 are the first representatives of cyclic compounds with this skeleton. 13C NMR spectroscopy allows the determination of the isomer type in a series of tris[1,2,4]triazolo[1,3,5]triazines.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 706–712, March, 2005. 相似文献
18.
Dominik Huber P. G. Anil Kumar Paul S. Pregosin Igor S. Mikhel Antonio Mezzetti 《Helvetica chimica acta》2006,89(8):1696-1715
Chloride abstraction from the half‐sandwich complexes [RuCl2(η6‐p‐cymene)(P*‐κP)] ( 2a : P* = (Sa,R,R)‐ 1a = (1Sa)‐[1,1′‐binaphthalene]‐2,2′‐diyl bis[(1R)‐1‐phenylethyl)]phosphoramidite; 2b : P* = (Sa,R,R)‐ 1b = (1Sa)‐[1,1′‐binaphthalene]‐2,2′‐diyl bis[(1R)‐(1‐(1‐naphthalen‐1‐yl)ethyl]phosphoramidite) with (Et3O)[PF6] or Tl[PF6] gives the cationic, 18‐electron complexes dichloro(η6‐p‐cymene){(1Sa)‐[1,1′‐binaphthalene]‐2,2′‐diyl {(1R)‐1‐[(1,2‐η)‐phenyl]ethyl}[(1R)‐1‐phenylethyl]phosphoramidite‐κP}ruthenium(II) hexafluorophosphate ( 3a ) and [Ru(S)]‐dichloro(η6‐p‐cymene){(1Sa)‐[1,1′‐binaphthalene]‐2,2′‐diyl {(1R)‐1‐[(1,2‐η)‐naphthalen‐1‐yl]ethyl}[(1R)‐1‐(naphthalen‐1‐yl)ethyl]phosphoramidite‐κP)ruthenium(II) hexafluorophosphate ( 3b ), which feature the η2‐coordination of one aryl substituent of the phosphoramidite ligand, as indicated by 1H‐, 13C‐, and 31P‐NMR spectroscopy and confirmed by an X‐ray study of 3b . Additionally, the dissociation of p‐cymene from 2a and 3a gives dichloro{(1Sa)‐[1,1′‐binaphthalene]‐2,2′‐diyl [(1R)‐(1‐(η6‐phenyl)ethyl][(1R)‐1‐phenylethyl]phosphoramidite‐κP)ruthenium(II) ( 4a ) and di‐μ‐chlorobis{(1Sa)‐[1,1′‐binaphthalene]‐2,2′‐diyl [(1R)‐1‐(η6‐phenyl)ethyl][(1R)‐1‐phenylethyl]phosphoramidite‐κP}diruthenium(II) bis(hexafluorophosphate) ( 5a ), respectively, in which one phenyl group of the N‐substituents is η6‐coordinated to the Ru‐center. Complexes 3a and 3b catalyze the asymmetric cyclopropanation of α‐methylstyrene with ethyl diazoacetate with up to 86 and 87% ee for the cis‐ and the trans‐isomers, respectively. 相似文献
19.
On the Formation of Intermetalloid Clusters: Titanocene(III)diammin as a Versatile Reactant Toward Nonastannide Zintl Clusters
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Dr. Christian B. Benda Dr. Markus Waibel Prof. Dr. Thomas F. Fässler 《Angewandte Chemie (International ed. in English)》2015,54(2):522-526
The reactivity of TiCp2Cl2 (d0) towards Zintl clusters was studied in liquid ammonia (Cp=cyclopentadienyl). Reduction of TiIVCp2Cl2 and ligand exchange led to the formation of [TiIIICp2(NH3)2]+, also obtainable by recrystallization of [CpTiIIICl]2. Upon reaction with [K4Sn9], ligand exchange leads to [TiCp2(η1‐Sn9)(NH3)]3?. A small variation of the stoichiometry led to the formation of [Ti(η4‐Sn8)Cp]3?, which cocrystallizes with [TiCp2(NH3)2]+ and [TiCp2(η1‐Sn9)(NH3)]3?. Finally, the large intermetalloid cluster anion [Ti4Sn15Cp5]n? (n=4 or 5) was obtained from the reaction of K12Sn17 and TiCp2Cl2 in liquid ammonia. The isolation of three side products, [K([18]crown‐6)]Cp, [K([18]crown‐6)]Cp(NH3), and [K([2.2]crypt)]Cp, suggests a stepwise elimination of the Cl? and Cp? ligands from TiCp2Cl2 and thus gives a hint to the mechanism of the product formation in which [Ti(η4+2‐Sn8)Cp]3? has a key role. 相似文献
20.
《Journal of Coordination Chemistry》2012,65(9):1591-1601
Three compounds, [Zn2L2(4,4′-bpt)2] n (1), [Cd2L2(3,4′-bpt)(H2O)2] n (2) and {[CoL(3,3′-bpt)(H2O)]?H2O} n (3) (L?=?3-Cl-1,2-benzenedicarboxylate dianion, 4,4′-bpt?=?1H-3,5-bs(4-pyridyl)-1,2,4-itriazole, 3,4′-bpt?=?1H-3-(3-pyridyl)-5-(4-pyridyl)-1,2,4-triazole and 3,3′-bpt?=?1H-3,5-bis(3-pyridyl)-1,2,4-triazole), based on three positionally isomeric triazole-bipyridine ligands, were synthesized. Structural analyses of 1–3 reveal diverse 2-D network structures, which are based on different [ML] n (M?=?Zn, Cd, Co) chains. In the [ZnL] n chains of 1, the carboxylic groups of L connect the adjacent Zn(II) centers with a monodentate bridging coordination mode (μ2-η1 ?/? η1 ). In 2, [CdL] n is a double chain connected by the carboxylic groups of L with μ3-η1 ?/? η2/η2 and μ3-η1 ?/? η1 ?/? η2 bridges. The [CoL] n chains of 3 are formed by the carboxylic groups of L with the μ2-η1 ?/? η2 coordination mode. The powder X-ray diffraction and the thermal stability of 1–3, the luminescent properties of 1 and 2, and the magnetic behavior of 3 have been briefly investigated. 相似文献