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1.
The diketone complex [W(CO) 2(η-C 5H 4Me){η 3- (H)---C(O)---C 5Me 5}] (3) was isolated from the reaction of PhC 2H with a mixture of [Ni(CO)I(η-C 5Me 5)] and [W(CO) 3(η-C 5H 4Me)] −. Complex 3 contains an organic diketone fragment that is bound in a π-allyl fashion to a tungsten atom. It was fully characterized by standard spectroscopic techniques and by a single-crystal X-ray diffraction study. The relationship of complex 3 to a structurally characterized cyclopentadienyl tungsten η 2-ketone species 1, and the likelihood that 3 and the methylcyclopentadienyl analog of 1 share common intermediates, are discussed. 相似文献
2.
The reactions of the cyclo-aurated gold(III) dihalide complex [{C 6H 3(CH 2NMe 2)-2-(OMe)-5}AuCl 2] with N-cyanoacetylurethane [NCCH 2C(O)NHCO 2Et], 2-benzoylacetanilide [PhC(O)CH 2C(O)NHPh] and acetoacetanilide [MeC(O)CH 2C(O)NHPh], and [{C 6H 4(CH 2NMe 2)-2}AuCl 2] with acetoacetanilide in dichloromethane with excess silver(I) oxide gives the first examples of auralactam complexes, containing
(O)---CHR′ four-membered rings. A single-crystal X-ray diffraction study on the complex [{C 6H 4(CH 2NMe 2)-2}A
H(COMe)}] reveals similar structural features to related metallalactam complexes of platinum(II) and palladium(II). When a CDCl 3 solution of the complex [{C 6H 3(CH 2NMe 2)-2-(OMe)-5}A
HCN}] is allowed to stand for 18 h, a novel dimerisation reaction occurs, giving the insoluble product [{C 6H 3(CH 2NMe 2)-2-(OMe)-5}Au{N(CO 2Et)C(O)CHCN}] 2·2CDCl 3, characterised by an X-ray structure determination. The dimer contains an eight-membered A ring. 相似文献
3.
The metallo-phosphaalkenes (η 5-C 5Me 5)(CO) 2FeP=C(R)(SiMe 3) ( Ia: R = SiMe 3, Ib: R = Ph) and MeO 2C---CC---CO 2Me undergo a dipolar [3+2]-cycloaddition to afford the metallo-heterocycles [(η 5-C 5Me 5)(CO) =C(R)SiMe 3] ( IIIa,b) with exocyclic P=C double bonds. 相似文献
4.
The reactions of RNHSi(Me) 2Cl (1, R= t-Bu; 2, R=2,6-(Me 2CH) 2C 6H 3) with the carborane ligands, nido-1-Na(C 4H 8O)-2,3-(SiMe 3) 2-2,3-C 2B 4H 5 (3) and Li[ closo-1-R′-1,2-C 2B 10H 10] (4), produced two kinds of neutral ligand precursors, nido-5-[Si(Me) 2N(H)R]-2,3-(SiMe 3) 2-2,3-C 2B 4H 5, (5, R= t-Bu) and closo-1-R′-2-[Si(Me) 2N(H)R]-1,2-C 2B 10H 10 (6, R= t-Bu, R′=Ph; 7, R=2,6-(Me 2CH) 2C 6H 3, R′=H), in 85, 92, and 95% yields, respectively. Treatment of closo-2-[Si(Me) 2NH(2,6-(Me 2CH) 2C 6H 3)]-1,2-C 2B 10H 11 (7) with three equivalents of freshly cut sodium metal in the presence of naphthalene produced the corresponding cage-opened sodium salt of the “carbons apart” carborane trianion, [ nido-3-{Si(Me) 2N(2,6-(Me 2CH) 2C 6H 3)}-1,3-C 2B 10H 11] 3− (8) in almost quantitative yield. The reaction of the trianion, 8, with anhydrous MCl 4 (M=Ti and Zr) in 1:1 molar ratio in dry tetrahydrofuran (THF) at −78 °C, resulted in the formation of the corresponding half-sandwich neutral d 0-metallacarborane, closo-1-M[(Cl)(THF) n]-2-[1′-η 1σ-N(2,6-(Me 2CH) 2C 6H 3)(Me) 2Si]-2,4-η 6-C 2B 10H 11 (M=Ti (9), n=0; M=Zr (10), n=1) in 47 and 36% yields, respectively. All compounds were characterized by elemental analysis, 1H-, 11B-, and 13C-NMR spectra and IR spectra. The carborane ligand, 7, was also characterized by single crystal X-ray diffraction. Compound 7 crystallizes in the monoclinic space group P2 1/ c with a=8.2357(19) Å, b=28.686(7) Å, c=9.921(2) Å; β=93.482(4)°; V=2339.5(9) Å 3, and Z=4. The final refinements of 7 converged at R=0.0736; wR=0.1494; GOF=1.372 for observed reflections. 相似文献
5.
Treatment of 1,2- trans-C 5H 8(PCl 2) 2 with 1,2-C 2H 4(NHPr- i) 2 gave the C2-symmetric perhydro-1,6,2,5-diazaphosphocine C 5H 8{P(Cl)N(Pr- i)CH 2} 2- cyclo, which produced dissymmetric C 5H 8(PPh 2){P[N(Pr- i)CH 2] 2- cyclo} on further reaction with PhMgBr. Cleavage of the P---N bonds with gaseous HCl afforded C 5H 8(PPh 2)(PCl 2), which was converted to C 5H 8(PPh 2){P(OPh) 2} 2 by reaction with phenol. All chiral P, P derivatives were obtained as racemates as well as resolved (1 R,2 R)- and (1 S,2 S)-enantiomers. 相似文献
6.
The optically active indenyl complexes ((η 5-C 9H 7)Ru(L---L)Cl (where L---L is either ( S, S)-1,2-dimethyl-1,2-ethanediylbis(diphenylphosphine) (chiraphos) or ( R, R)-1,2-cyclopentanediylbis(diphenylphosphine) (cypenphos)) have been synthesized and spectroscopically characterized and compared with the corresponding cyclopentadienyl complexes. Reaction of the new complexes with 2-e-donors give cationic adducts in which the pentahaptocoordination of the indenyl ligand is maintained. The crystal structures of ( S, S)-(η 5-C 9H 7)Ru{Ph 2PCH(CH 3)CH(CH 3)PPh 2}Cl (1) and ( S, S)-η 5-C 5H 5Ru{Ph 2PCH(CH 3)CH(CH 3)PPh 2}Cl (3) have been determined. 相似文献
7.
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
8.
Synthesis of (2 R,3 S,4 S)-4-aryl-3-hydroxyprolinols has been established starting from 2-benzyloxymethylpyrrolidin-2-one framework, which is derived from commercially available trans-(2 S,4 R)-4-hydroxyproline. The single diastereomer having a trans–cis relative configuration with C 2 and C 3 and C 3 and C 4 is constructed in two one-pot functional group transformations of Grignard addition/dehydration and epoxidation/isomerization as the key steps in moderate yield. 相似文献
9.
The chiral bis-imine (1 R,2 R)-C 6H 10-[ E---N=CH---C 6H 3---3,4-(OMe) 2] 2 1 (LH) reacts with [Pd(OAc) 2] (1:1 molar ratio; OAc=acetate) giving the orthometallated [Pd(OAc)( C6H 2---4,5-(OMe) 2---2-CH= N-(1 R,2 R)-C 6H 10--- N=CH---C 6H 3-3′,4′-(OMe) 2-κ-C,N,N)] 2 (abbreviated as [Pd(OAc)(L-κ-C,N,N)]), through C---H bond activation on only one of the aryl rings and N, N-coordination of the two iminic N atoms. 2 reacts with an excess of LiCl to give [Pd(Cl)(L-κ-C,N,N)] 3. The reaction of 3 with AgClO 4 and neutral or anionic ligands L′ (1:1:1 molar ratio) affords [Pd(L-κ-C,N,N)(L′)](ClO 4) (L′=PPh 3 4a, NCMe 5, pyridine 6, p-nitroaniline 7) or [Pd(I)(L-κ-C,N,N)] 8. Complex 4a reacts with wet CDCl 3 giving [Pd( C6H 2---4,5-(OMe) 2---2-CH= N-(1 R,2 R)---C 6H 10--- NH 2-κ-C,N,N)(PPh 3)](ClO 4) 4b as a result of the hydrolysis of the C=N bond not involved in the orthometallated ring. The molecular structure of 4b·CH 2Cl 2 has been determined by X-ray diffraction methods. Cleavage of the Pd---N bond trans to the C aryl atom can be accomplished by coordination of strongly chelating ligands, such as acetylacetonate (acac) or bis(diphenylphosphino)ethane (dppe), forming [Pd(acac- O, O′)(L-κ-C,N)] 9 and [Pd(L-κ-C,N)(dppe-P,P′)](ClO 4) 12, while classical N, N′-chelating ligands such as 1,10-phenantroline (phen) or 2,2′-bipyridyl (bipy) behave as monodentate N-donor ligands yielding [Pd(L-κ-C,N,N)(κ 1-N-phen)](ClO 4) 10 and [Pd(L-κ-C,N,N)(κ 1-N-bipy)](ClO 4) 11. Treatment of 1 with PtCl 2(DMSO) 2 (1:1 molar ratio) in refluxing 2-methoxyethanol gives Cl 2Pt[( NH 2) 2C 6H 10---N,N′] 13a and [Pt(Cl)( C6H 2---4,5-(OMe) 2---2-CH= N-(1 R,2 R)---C 6H 10--- NH 2-κ-C,N,N)] 13b, while [Pt(Cl)(L-κ-C,N,N)] 14 can be obtained by reaction of [Pt(μ-Cl)(η 3-2-Me---C 3H 4)] 2 with 1 in refluxing CHCl 3. Complexes 2 and 3 catalyzed the arylation of methyl acrylate giving good yields of the corresponding methyl cinnamates and TON up to 847 000. Complex 3 also catalyzes the hydroarylation of 2-norbornene, but with lower yields and without enantioselectivity. 相似文献
10.
The reaction of [ R-( R, R)]-(+) 589-[(η 5-C 5H 5){1,2-C 6H 4(PMePh) 2}Fe(NCMe)]PF 6 with (±)-AsHMePh in boiling methanol yields crystalline [ R-[( R)-( R, R)]-(+) 589)-[(η5-C5H5){1,2-C6H4(PMePh)2}Fe(AsHMePH)PF 6, optically pure, in ca. 90% yield, in a typical second-order asymmetric transformation. This complex contains the first resolved secondary arsine. Deprotonation of the secondary arsine complex with KOBu t at −65°C gives the diastereomerically pure tertiary arsenido-iron complex [ R-[( R),( R, R)]]-[((η 5-C 5H 5){1,2-C 6H 4(PMePh) 2}FeAsMePh] · thf, from which optically pure [ R-[( S),( R, R)]]-(+) 589-[(η 5-C 5H 5){1,2-C 6H 4(PMePh) 2}Fe(AsEtMePh)PF 6 is obtained by reaction with iodoethane. Cyanide displaces ( R)-(−) 589-ethylmethylphenylarsine from the iron complex, thereby effecting the asymmetric synthesis of a tertiary arsine, chiral at arsenic, from (±)-methylphenylarsine and an optically active transition metal auxiliary. 相似文献
11.
Unlike bis(diphenyl)phosphine derivatives in general, (2 S,4 S)-pentane-2,4-diyl-bis(5 H-dibenzo[b]phosphindole), S, S-BDBPP, gives a trans oligomeric compound [PtCl 2( S, S-BDBPP)] n, 1, in reaction with dichloro-Pt precursors such as PtCl 2(PhCN) 2, PtCl 2(CH 3CN) 2 and PtCl 2(COD) at room temperature. Compound 1, which could be readily isolated, slowly rearranges in solutions at room temperature to the expected cis-monomer PtCl 2( S, S-BDBPP), 3. Heating or the presence of PtCl 2(COD) accelerates the transformation of compound 1 to 3. SnCl 2 adducts of both compounds, trans-[PtCl(SnCl 3)( S, S-BDBPP)] n, 2, and cis-PtCl(SnCl 3)( S, S-BDBPP), 4, as well as the known cis-PtCl(SnCl 3)( S, S-BDPP), 5, ( S, S-BDPP = (2 S,4 S)-2,4-bis(diphenylphosphino)pentane) have been tested as catalysts in the asymmetric hydroformylation of p-isobutylstyrene. The phenyl analog 5 provides up to 75% e.e. but moderate yields to chiral 2-(4-isobutylphenyl)-2-propanal. Compared to this, the regioselectivity to the branched aldehyde is remarkably increased; however, the enantioselectivity is drastically decreased by the use of both dibenzophosphole derivatives 2 and 4. The similarities in the selectivities provided by 2 and 4 indicate that the trans oligomer 2 transforms to the cis-monomer 4 during the catalytic process. X-ray crystal structure determination of compound 3 shows a half-chair conformation for the chelate ring with a symmetric arrangement of dibenzophosphole groups. Besides a preference for the latter achiral conformation, the planar structure of the dibenzophosphole groups can also be considered as reason for the moderate enantioselectivities provided by 4. 相似文献
12.
The preparation and properties as well as some reactions of a series of arylcarbonylbis(triphenylphosphine)iridium(I) complexes [Ir(Ar)(CO)(PPh 3) 2] (Ar = C 6H 5, C 6F 5, 2-C 6H 4CH 3, 3-C 6H 4CH 3, 4-C 6H 4CH 3, 2-C 6H 4OCH 3, 2,6-C 6H 3-(OCH 3) 2, 4-C 6H 4N(CH 3) 2, 3-C 6H 4Cl, 4-C 6H 4Cl, 4-C 6H 4Cl, 3-C 6H 4CF 3, 4-C 6H 4CF 3) are described, and the most important IR data as well as the 31P NMR parameters of these, without exception trans-planar, compounds are given. Some of the complexes react with molecular oxygen to form well defined dioxygen adducts [Ir(Ar)(O2)(CO)(PPh3)2] (Ar = C6H5, 3-C6H4CH3, 4-C6H4CH3). Complexes with ortho-substituted aryl ligands are not oxygenated. This effect is referred to as a steric shielding of the metal center by the corresponding ortho-substituents. With SO2 the similar irreversible addition compound [Ir(4-C6H4CH3)-(SO2)(CO)(PPh3)2] is obtained. Sulfur dioxide insertion into the Ir---C bond cannot be observed. The first step of the reaction between [Ir(4-C6H4CH3)(CO)(PPh3)2] and hydrogen chloride involves an oxidative addition of HCl to give [Ir(H)(Cl)(4-C6-H4CH3)(CO)(PPh3)2]. Ir---C bond cleavage by reductive elimination of toluene from the primary adduct does not occur except at elevated temperature. 相似文献
13.
硫代嘧啶碱基是光动力疗法潜在的重要光敏剂,其最低单重激发态的光物理研究已有广泛报道。然而,其较高激发态的跃迁性质和反应动力学研究较为稀少。因此,本文采用共振拉曼光谱和密度泛函理论计算方法研究2,4-二硫代尿嘧啶的紫外光谱和几个较高单重激发态的短时结构动力学。首先,基于共振拉曼光谱强度与电子吸收带振子强度f的关系,将紫外光谱去卷积成四个吸收带,分别为358 nm(f=0.0336)中等强度吸收带(A带),338 nm(f=0.1491)、301 nm(f=0.1795)和278 nm(f=0.3532)强而宽的吸收带(B、C和D带)。这一结果既吻合密度泛函理论计算结果,又符合共振拉曼光谱强度模式对紫外光谱带的预期。据此,去卷积得到的四个吸收带被分别指认为S0→S2跃迁、S0→S6跃迁、S0→S7跃迁和S_0→S_8跃迁。同时,分别对B,C和D带共振拉曼光谱进行了详细的指认,获得了短时动力学信息。结果表明,S_8态短时动力学的显著特征是在Franck-Condon区域或附近发生了S8(ππ~*)/S(nπ~*)势能面交叉引发的、伴随超快结构扭转的非绝热过程。S7和S6态短时动力学的主要特征是反应坐标的多维性,它们分别沿C_5C_6/C_2S_8/C_4S_(10)/N_2C_3+C_4N_3H_9/N_1C_2N_3/C_2N_1C_6/C_6N_1H_7/C_5C_6H_(12)和C_5C_6/N_3C_2/C_4S_(10)/C_2S_8+C_6N_1H_7/C_5C_6H_(12)/C_5C_6N_1/C_5C_6H_(12)/C_2N_1C_6/N_1C_2N_3/C_4N_3H_9/N_1C_2N_3等内坐标演化。 相似文献
14.
The carbonyl derivatized bis(alkyne) O=C(4-C 6H 4OCH 2CCH) 2 was converted into the imine derivatives RN=C(4-C 6H 4OCH 2CCH) 2 [R=OH, NHC(O)NH 2, NHC 6H 3-2,4-(NO 2) 2] and into the 4-bromomethyl-1,3-dioxolane derivative BrCH 2C 2H 3O 2C(4-C 6H 4OCH 2CCH) 2. The alkyne units in these compounds react with [AuCl(SMe 2)] in the presence of base to form the corresponding digold(I) diacetylide complexes, that exist as insoluble oligomers or polymers. They reacted with the diphosphines Ph 2PZPPh 2 [Z=CC, trans-HC=CH and (CH 2) n, n=3–5] to give macrocyclic gold(I) complexes of the type [Au 2(μ-LL)(μ-PP)], where LL is the diacetylide and PP the diphosphine ligand. The ability of these macrocyclic complexes to self-assemble to [2]catenanes has been studied. The ketone and imine derivatives do not form [2]catenanes because the orientation of the aryl groups is unfavorable, but the 1,3-dioxolane derivatives may catenate if the ring size is optimum. 相似文献
15.
The compounds (π-C 5H 5)(CO) 2LM-X (L = CO, PR 3; M = Mo, W; X = BF 4, PF 6, AsF 6, SbF 6) react with H 2S, p-MeC 6H 4SH, Ph 2S and Ph 2SO(L′) to give ionic complexes [(π-C 5H 5)(CO) 2LML′] + X −. Also sulfur-bridged complexes, [(π-C 5H 5)(CO) 3W---SH---W(CO) 3(π-C 5H 5)] + AsF 6− and [(π-C 5H 5)(CO) 3M-μ-S 2C=NCH 2Ph-M(CO) 3(π-C 5H 5)], have been obtained. Reactions with SO 2 and CS 2 have been examined. 相似文献
16.
Two organogold derivatives of diphenylmethane and diphenylethane, Ph 3PAu( o-C 6H 4)CH 2(C 6H 4- o)AuPPh 3 (1) and Ph 3PAu( o-C 6H 4)(CH 2) 2(C 6H 4- o)AuPPh 3 (2), have been synthesized by the reaction of ClAuPPh 3 with Li( o-C 6H 4)CH 2(C 6H 4- o)Li and Li( o-C 6H 4)(CH 2) 2(C 6H 4- o)Li respectively. The interaction of 1 with dppe results in the replacement of the two PPh 3 groups to give a macrocyclic compound (3) that includes an Au Au bond. Compounds 1 and 2 react with one or two equivalents of [Ph 3PAu]BF 4 to form new types of cationic complex [CH 2(C 6H 4- o) 2(AuPPh 3) 3]BF 4 (4), [CH 2(C 6H 4- o) 2(AuPPh 3) 4](BF 4) 2 (5), and [(CH 2) 2(C 6H 4- o) 2(AuPPh 3) 4](BF 4) 2 (6). Complexes 1–6 have been characterized by X-ray diffraction studies, FAB MS, and IR as well as by 1H and 31P NMR spectroscopy. A complicated system of Au H-C agostic interactions, involving the bridging alkyl groups (—CH 2— and CH 2-CH 2—) of diphenylmethane and diphenylethane ligands, has been found to occur in complexes 1–3 and 6. 相似文献
17.
The dimethylphosphino substituted cyclopentadienyl precursor compounds [M(C 5Me 4CH 2PMe 2)], where M=Li + (1), Na + (2), or K + (3), and [Li(C 5H 4CR′ 2PMe 2)], where R′ 2=Me 2 (4), or (CH 2) 5 (5), [HC 5Me 4CH 2PMe 2H]X, where X −=Cl − (6) or PF 6− (7) and [HC 5Me 4CH 2PMe 2] (8), are described. They have been used to prepare new metallocene compounds, of which representative examples are [Fe(η-C 5R 4CR′ 2PMe 2) 2], where R=Me, R′=H (9); R=H and R′ 2=Me 2 (10), or (CH 2) 5 (11), [Fe(η-C 5H 4CMe 2PMe 3) 2]I 2 (12), [Fe{η-C 5Me 4CH 2P(O)Me 2} 2] (13), [Zr(η-C 5R 4CR′ 2PMe 2) 2Cl 2], where R=H, R′=Me (14), or R=Me, R′=H (15), [Hf(η-C 5H 4CMe 2PMe 2) 2]Cl 2] (16), [Zr(η-C 5H 4CMe 2PMe 2) 2Me 2] (17), {[Zr(η-C 5Me 4CH 2PMe 2) 2]Cl}{(C 6F 5) 3BClB(C 6F 5) 3} (18), [Zr{(η-C 5Me 4CH 2PMe 2) 2Cl 2}PtI 2] (19), [Mn(η-C 5Me 4CH 2PMe 2) 2] (20), [Mn{(η-C 5Me 4CH 2PMe 2B(C 6F 5) 3} 2] (21), [Pb(η-C 5H 4CMe 2PMe 2) 2] (23), [Sn(η-C 5H 4CMe 2PMe 2) 2] (24), [Pb{η-C 5H 4CMe 2PMe 2B(C 6F 5) 3} 2] (25), [Pb(η-C 5H 4CMe 2PMe 2) 2PtI 2] (26), [Rh(η-C 5Me 4CH 2PMe 2)(C 2H 4)] 29, [M(η,κ P-C 5Me 4CH 2PMe 2)I 2], where M=Rh (30), or Ir, (31). 相似文献
18.
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
19.
The complexes [Fe{η-C 5H 4---( E)---CH=CH---4-C 6H 4CCX} 2] [X=SiMe 3 (1), H (2), Au(PCy 3) (3), Au(PPh 3) (4), Au(PMe 3) (5), RuCl(dppm) 2 (7), RuCl(dppe) 2 (8)] and [Fe{η-C 5H 4---( E)---CH=CH---4-C 6H 4CH=CRuCl(dppm) 2} 2](PF 6) 2 (6) have been prepared and the identities of 1 and 7 confirmed by single-crystal X-ray structural studies. Complexes 1–8 exhibit reversible oxidation waves in their cyclic voltammograms attributed to the Fe II/III couple of the ferrocenyl groups, 6–8 also showing reversible (7, 8) or non-reversible (6) processes attributed to Ru-centered oxidation. Cubic nonlinearities at 800 nm by the Z-scan method are low for 1–5; in contrast, complexes 6 and 7 exhibit large negative γreal and large γimag values. A factor of 4 difference in γ and two-photon absorption cross-section σ2 values for 6 and 7 suggest that they have potential as protically switchable NLO materials. 相似文献
20.
Excess molar enthalpies HE and excess molar volumes VE have been measured, as a function of mole fraction x1, at 298.15 K and atmospheric pressure for the five liquid mixtures ( x11,4-C 6H 4F 2 + x2n-C lH 2l+2), l = 7, 8, 10, 12 and 16. In addition, HE and excess molar heat capacities CPE at constant pressure have been determined for the two liquid mixtures ( x1C 6F 6 + x2n-C lH 2l+2), l = 7 and 14, at the same temperature and pressure. The instruments used were flow microcalorimeters of the Picker design (the HE version was equipped with separators) and a vibrating-tube densimeter, respectively. The excess enthalpies of the five difluorobenzene mixtures are all positive and quite large; they increase with increasing chain length l of the n-alkane from HE(x1 = 0.5)/(J mol−1) = 1050 for l = 7 to 1359 for l = 16. The corresponding excess volumes VE are all positive and also increase with increasing l: VE(x1 = 0.5)/(cm3 mol−1) = 0.650 for l = 7 and 1.080 for l = 16. Interestingly, the excess enthalphies of the corresponding mixtures with hexafluorobenzene are only about 5% larger, whereas the excess volumes of (x1C6F6 + x2n-ClH2l+2) are roughly twice as large as those of their counterparts in the series containing 1,4-C6H4F2. Specifically, at 298.15 K HE(x1 = 0.5)/(J mol−1) = 1119 for (x1C6F6 + x2n-C7H16) and 1324 for (x1C6F6 + x2n-C14H30), and for the same mixtures VE(x1 = 0.5)/(cm3 mol−1) = 1.882 and 2.093, respectively. The excess heat capacities for both systems are negative and of about the same magnitude as the excess heat capacities of mixtures of fluorobenzene with the same n-alkanes (Roux et al., 1984): CPE(x1 = 0.5)/(J K−1 mol−1) = −1.18 for (x1C6F6 + x2n-C7H16), and −2.25 for (x1C6F6 + x2n-C14H30). The curve CPE vs. (x1 for x1C6F6 + x2n-C14H30) shows a sort of “hump” for x1 0.5, which is presumed to indicate emerging W-shape composition dependence at lower temperatures. 相似文献
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