Synthesis of 2-Aryl-3-hydroxy-4,9-dihydrocyclohepta[b]pyran-4,9-diones

3-(2-Bromoacetyl)tropolone ( 1 ) reacted with benzaldehydes 2a-g in the pressence of alkali at low temperature to give 2-aryl-3-hydroxy-4,9-dihydrocyclohepta[b]pyran-4,9-diones 3a-g in good yields.     

Synthesis,characterization, and DNA-binding of [Co(phen)2(CPIA)]3+, [Co(phen)2(BIP)]3+, and [Co(phen)2(CIP)]3+

Three ligands, 2-(3-(carboxymethyl)-1,10-phenanthroline-[5,6-d]imidazole-1-yl)acetate (CPIA), 2-(benzo[d][1,3]dioxol-4-yl)-1H-imidazo[4,5-f][1,10]phenanthroline (BIP), and 2-(9H-carbazol-3-yl)-1H-imidazo[4,5-f][1,10]phenanthroline (CIP), and their complexes, [Co(phen)₂(CPIA)]³⁺ (1) (phen = 1,10-phenanthroline), [Co(phen)₂(BIP)]³⁺ (2), and [Co(phen)₂(CIP)]³⁺ (3), have been synthesized and characterized. Binding of the three complexes with calf thymus DNA (CT-DNA) has been investigated by spectroscopic methods, cyclic voltammetry, and viscosity measurements. The three complexes bind to DNA through an intercalative mode, and the size and shape of the intercalative ligands have significant effects on the binding affinity of complexes to CT-DNA.     

Stereodynamics of 9,11-Diphenyl-10-azatetracyclo[6.3.0.0.(4,11)0.(5,9)]undecanes. Highly Restricted Nitrogen Inversion and Isolated Phenyl Rotation. X-ray Crystallographic, Dynamic NMR, and Molecular Mechanics Studies

The (1)H NMR spectra of 10-benzyl-9,11-diphenyl-10-azatetracyclo[6.3.0.0.(4,11)0.(5,9)]undecane (BnPh(2)()) and 10-methyl-9,11-diphenyl-10-azatetracyclo[6.3.0.0.(4,11)0.(5,9)]undecane (MePh(2)()) decoalesce due to slowing inversion at nitrogen and to slowing isolated bridgehead phenyl rotation. The high nitrogen inversion barriers in MePh(2)() (DeltaG() = 12.2 +/- 0.1 kcal/mol at 250 K) and BnPh(2)() (DeltaG() = 10.6 +/- 0.1 kcal/mol at 215 K) are typical of tertiary amines in which at least one C-N-C bond angle is constrained to a small value. Compared to the minuscule rotation barriers about sp(2)-sp(3) carbon-carbon bonds in simple molecular systems, the bridgehead phenyl rotation barriers in MePh(2)() (DeltaG() = 9.8 +/- 0.1 kcal/mol at 210 K) and BnPh(2)() (DeltaG() = 9.8 +/- 0.1 kcal/mol at 210 K) are unusually high. Molecular mechanics calculations (MMX force field) suggest that the origin of the high phenyl rotation barriers lies in the close passage of an o-phenyl proton and a methyl (or benzylmethylene) proton in the transition state. BnPh(2)() crystallized from hexane as white needles in the monoclinic system Pn. Unit cell dimensions are as follows: a = 12.198(1) ?, b = 6.1399(6) ?, c = 14.938(2) ?, beta = 107.470(4) degrees, V = 1067.1(2) ?(3), Z = 2. In the crystal molecular structure, the imine bridge CNC bond angle in BnPh(2)() is constrained to a small value (96 degrees ). The benzylic phenyl group is oriented gauche to the nitrogen lone pair.     

含双齿酸性烯醇式β-双酮的十配位稀土金属配合物[Ce(NO3)2(phen)2(CH3COCHCOCH3)]·H2O的合成与晶体结构

标题化合物由邻菲罗啉和乙酰丙酮等在无水乙醇和蒸馏水的混合溶剂中合成 ,用IR谱和X射线结构分析进行表征。晶体学数据如下 :C2 9H2 5N6O9Ce ,Mr=741.6 7,单斜 ,a =1.1110 ( 2 )nm ,b =0 .9834( 2 )nm ,c =1.344 9( 3)nm ,β =10 2 .0 3( 3)°,V =1.4371( 5 )nm3 ,Z =2 ,Dc=1.714kg·m- 3 ,F( 0 0 0 ) =742 ,μ(MoKα) =1.6 5 0mm- 1 ,R =0 .0 42。结果表明 ,具有十配位的中心Ce+3 含有一个双齿负离子烯醇式的β 双酮作为配体。对乙酰丙酮以双齿酸性烯醇式与Ce的配合型式进行了讨论     

[Gd(3-HPYA)3(H2O)]n的合成及其晶体结构

3-(3-吡啶基)丙烯酸(3-HPYA)配体与稀土金属离子钆(Gd)通过水热法合成了一种新的一维链状配位聚合物[Gd(3-HPYA)3(H2O)]n(1),其结构经IR,热重分析,元素分析和x-射衍单晶衍射仪表征.1属于三斜晶系,空间群P-1,晶胞参数为:a=0.61943(15)nm,b=1.27000(3)nm,c=1.563 40(4)nm,α=111.728(4)°,β=90.330(4)°,γ=95.202(4)°,Z=2.1通过分子间的氢键堆积为三维网状结构.对1的热稳定性进行了研究.     

Unsaturated Ru(0) species with a constrained bis-phosphine ligand: [Ru(CO)2(tBu2PCH2CH2PtBu2)]2. Comparison to [Ru(CO)2(PtBu2Me)2

The synthesis of Ru(C2H4)(CO)2(dtbpe) (dtbpe = tBu2PC2H4PtBu2), then green [Ru(CO)2(dtbpe)]n is described. In solution, n = 1, while in the solid state, n = 2; the dimer has two carbonyl bridges. DFTPW91, MP2, and CCSD(T) calculations show that the potential energy surface for bending one carbonyl out of the RuP2C(O) plane is essentially flat. Ru(CO)2(dtbpe) reacts rapidly in benzene solution to oxidatively add the H-E bond of H2, HCl, HCCR (R = H, Ph), [HOEt2]BF4, and HSiEt3. The H-C bond of C6HF5 oxidatively adds at 80 degrees C. CO adds, as does the C=C bond of H2C=CHX (X = H, F, Me). The following do not add: N2, THF, acetone, H3COH, and H2O.     

Retrospective View on Recent Developments in Cyclobutane Synthesis via [2+2] Photocycloaddition of Unsaturated Ketones to Acyclic Dienes

This synopsis addresses cyclobutane formation via light‐induced [2+2] cycloaddition from both cyclic and acyclic unsaturated carbonyl compounds, and 2,3‐dimethylbuta‐1,3‐diene     

Li+ cation coordination in [Li2(CF3SO3)2(diglyme)] and [Li3(C2F3O2)3(diglyme)]

The title compounds, poly­[[[bis(2‐methoxy­ethyl) ether]­lithium(I)]‐di‐μ₃‐tri­fluoro­methanesulfonato‐lithium(I)], [Li₂(CF₃SO₃)₂(C₆H₁₄O₃)]_n, and poly­[[[bis(2‐methoxy­ethyl) ether]­lithium(I)]‐di‐μ₃‐tri­fluoro­acetato‐dilithium(I)‐μ₃‐tri­fluoro­acetato], [Li₃(C₂F₃O₂)₃(C₆H₁₄O₃)]_n, consist of one‐dimensional polymer chains. Both structures contain five‐coordinate Li⁺ cations coordinated by a tridentate diglyme [bis(2‐methoxy­ethyl) ether] mol­ecule and two O atoms, each from separate anions. In both structures, the [Li(diglyme)X₂]^? (X is CF₃SO₃ or CF₃CO₂) fragments are further connected by other Li⁺ cations and anions, creating one‐dimensional chains. These connecting Li⁺ cations are coordinated by four separate anions in both compounds. The CF₃SO₃^? and CF₃CO₂^? anions, however, adopt different forms of cation coordination, resulting in differences in the connectivity of the structures and solvate stoichiometries.     

Synthesis,Crystal Structure and Luminescence of [Ag(PPh3)2(H2TMT)]

The silver complex Ag(PPh₃)₂(H₂TMT) ( 1 )(H₃TMT = 2,4,6‐trimercapto‐1,3,5‐triazine) has been synthesized and characterized. The ligand trimercaptotriazine exhibits a novel coordination mode and the complex shows a special hydrogen bonding linkage in the crystal packing. The colorless crystals of 1 exhibit broad emission in the visible region at room temperature. TDDFT calculation indicated that the π–π attraction is crucial for fluorescence of the title complex.     

Synthesis,structure, and kinetic studies on [RuCl2(NCCH3)2(cod)]

[RuCl₂(NCCH₃)₂(cod)], an alternative starting material to [RuCl₂(cod)] _n for the preparation of ruthenium(II) complexes, has been prepared from the polymer compound and isolated in yields up to 87% using a new work-up procedure. The compound has been obtained as a yellow solid without water of crystallization. The complexes [RuCl₂(NCR)₂(cod)] spontaneously transform into dimers [Ru₂Cl(μ-Cl)₃(cod)₂(NCR)] (R?=?Me, Ph). ¹H NMR kinetic experiments for these transformations evidenced first-order behavior. [RuCl₂(NCPh)₂(cod)] dimerizes slower by a factor of ten than [RuCl₂(NCCH₃)₂(cod)]. The following activation parameters, ΔH ^#?=?114?±?3?kJ?mol^?1 and ΔS ^#?=?66?±?9?J?K^?1?mol^?1 for R?=?CH₃CN (ΔG ^#?=?94?±?5?kJ?mol^?1, 298.15?K) and ΔH ^#?=?122?±?2?kJ?mol^?1 and ΔS ^#?=?75?±?6?J?K^?1?mol^?1 for R?=?Ph (ΔG ^#?=?100?±?4?kJ?mol^?1, 298.15?K), have been calculated from the first-order rate constants in the temperature range 294–323?K. The kinetic parameters are in agreement with a two-step mechanism with dissociation of acetonitrile as the rate-determining step. The molecular structures of [Ru₂Cl(μ-Cl)₃(cod)₂(NCR)] (R?=?Me, Ph) have been determined by X-ray diffraction.     

配合物[UO2(PMBP)2(DMDBU)]的合成和晶体结构

1-苯基-3-甲基-4-苯甲酰基-吡唑啉酮-5(HPMBP)是一类含有氮杂环的β-二酮螯合剂,现在已经广泛应用于金属离子的分离和分析[1-4]。最近我们采用取代脲N,N-二甲基-N,N-二苯基脲(DMDBU)和N,N-二乙基-N,N-二苯基脲(DED-BU)应用于铀(VI)和钍(IV)萃取研究,并合成和测定了配合物[UO2(D     

Synthesis and Crystal Structure of [Cr(thd)2(OEt)]2

The mixed‐ligand complex [Cr(thd)₂(OEt)]₂ [(thd)^– = anion of H(thd) = C₁₁H₂₀O₂ = 2,2,6,6‐tetramethylheptane‐3,5‐dione] appears as by‐product when EtOH/H₂O is used as solvent during preparation of Cr(thd)₃. [Cr(thd)₂(OEt)]₂ can be difficult to separate from Cr(thd)₃ by sublimation, but separation is easily accomplished by extracting Cr(thd)₃ with acetone. A detailed account for the sublimation behavior of [Cr(thd)₂(OEt)]₂/Cr(thd)₃ mixtures is advanced. Good yields of [Cr(thd)₂(OEt)]₂ are obtained when CrCl₃, H(thd), and Na(EtO) react in absolute EtOH. [Cr(thd)₂(OEt)]₂ is obtained in the form of green needle‐shaped crystals by recrystallization from toluene. The crystal structure is triclinic [a = 10.2919(15), b = 10.6686(16), c = 14.194(3) Å, α = 106.559(2), β = 107.869(2), and γ = 98.326(2)° at 295 K; space group P . The complex contains two crystallographic equivalent chromium atoms, which are bridged by two cis‐configured ethoxy groups, the four remaining sites in the octahedral coordination around each chromium atom being occupied by oxygen atoms from two thd ligands. The bond lengths and angles concur with the findings for related molecular complexes. The temperature dependence of the magnetic susceptibility of [Cr(thd)₂(OEt)]₂ follows Curie–Weiss law with Weiss constant θ ≈? –65 K and μ_p = 3.87 μ_B.