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1.
Recently, we have prepared a novel class of DNA analogues containing the [3′-NH-P(CH3)(O)-O-5′] methanephosphonamidate linkage. Synthesis of such analogues requires preparation of the dinucleoside methanephosphonamidates N×N, where N is a 2′-deoxyribonucleoside moiety and × is the methanephosphonamidate linkage. Dimers T×T and C×T were obtained in a non-stereospecific manner giving rise to a pair of P-chiral diastereomers. Such diastereomers were effectively separated into fast and slow migrating ones by means of chromatographic methods (TLC). As described in our previous work (Nawrot et al. Nucleic Acids Res.1998, 26, 2650), the stereochemistry of the phosphorus chiral center of T×T fast migrating diastereomer is RP and of T×T slow migrating diastereomer is SP, as established by means of 2D ROESY experiments. Here we describe assignment of the absolute configuration at the phosphorus center of fast and slow migrating diastereomers of C×T dimer. The 2D ROESY sequence with phosphorus decoupling during acquisition used in these measurements allowed observation of the P-Me group as a singlet instead of a 1H-31P-coupled doublet. The apparent advantage of this approach was a much better signal to noise ratio and improved resolution in the F1 dimension. For the fast migrating C×T diastereomer an RP and for slow migrating C×T diastereomer an SP configuration was assigned. Conformational analysis of both pairs of diastereomers T×T and C×T indicates significant differences in sugar ring puckering, which strongly depend on the nature of the nucleobase at the 5′-terminus of the dimer. The ribose rings of the 3′-amino-2′,3′-dideoxycytidine moiety of both diastereomers of C×T adopt predominantly a C3′-endo (North) conformation, while thymine-substituted ribofuranoses originating either from C×T or T×T dimers prefer a C2′-endo (South) conformation. 相似文献
2.
A new dithioligand [N′-(2-methoxybenzoyl)hydrazinecarbodithioate] ethyl ester (H2mbhce, 1) formed complexes [M(Hmbhce)2]n {M = Mn(II), Cd(II)} which have been characterized with the help of elemental analyses, magnetic susceptibility measurements, IR, UV–Vis, 1H and 13C NMR and mass spectrometry. [Mn(Hmbhce)2]n (2) crystallized in monoclinic system with space group P21/n. In the polymeric structure of 2, the ligand acts as an uninegative tridentate N(1), O(1), S(3) donor and forms a five membered chelate ring with N(1), C(2) and O(1). The intermediate bond lengths (between single and double bond distances) O(1)–C(2) = 1.241(3), N(2)–C(2) = 1.325(3), N(1)–N(2) = 1.393(2), N(1)–C(8) = 1.311(3) ? and C(8)–S(3) = 1.704(2) Å suggest considerable delocalization of charge which develops slightly aromatic character in the chelate ring. 相似文献
3.
The reaction of AgOTf in dichloromethane with bis(2-(diphenylphosphino)phenyl) ether (DPEphos) in an equimolar ratio afforded a dinuclear complex [Ag2(κ2-P,P′-DPEphos)2(μ-OTf)2] (1), whereas the similar reaction in a 1:2 molar ratio resulted in the formation of a bis-chelating complex [Ag(κ2-P,P′-DPEphos)2][OTf] (2). The silver(I) complex 1 was obtained as a dimer, in which two silver atoms are bridged by two triflate groups to form three adjacent eight-membered spirocyclic rings. The mixed-ligand complex [Ag(κ2-P,P′-DPEphos)(2,2′-bpy)][OTf] (3) was obtained in the reaction of 1 in dichloromethane with 2,2′-bipyridine. The crystal structures of complexes 1–3 were determined by single crystal X-ray analyses. 相似文献
4.
Qing-Xiang Liu Meng-Chao ShiZhi-Qiang Wang Shu-Wen LiuShu-Sheng Ge Yan ZangXiu-Guang Wang Jian-Hua Guo 《Polyhedron》2010
The alkyl chain-linked diimidazolium (or dibenzimidazolium) salts, 1,1′-diethyl-4,4′-tetramethylene-diimidazolium-diiodide (L1H2·I2) and 1,1′-diethyl-3,3′-trimethylene-dibenzimidazolium-diiodide (L2H2·I2), and their silver(I) and copper(II) coordination polymers, [L1AgI]n (1) and [L2Cu2I4]n (2), have been prepared and characterized. Complex 1 is a 1D helical polymer generated by bidentated carbene ligands (L1) and Ag(I) atoms. The 1D polymer of 2 is formed by bidentated carbene ligands (L2) and coplanar quadrilateral Cu2I2 units. 3D supramolecular frameworks in the crystal packings of 1 and 2 are formed via intermolecular weak interactions, including C–H···π contacts, π–π interactions and C–H···I hydrogen bonds. 相似文献
5.
Alexander Steiner Stefano ZacchiniPhilip I Richards 《Coordination chemistry reviews》2002,227(2):193-216
This review deals with the chemistry and coordination behaviour of imino-aza phosphorus(V) ligands focussing on s- and p-block as well as Group 11 and 12 metal complexes. Imino phosphorus(V) ligands contain one or more terminal RNP-units, which include iminophosphoranes R3PNR′, monoanionic diiminophosphinates [R2P(NR′)2]−, dianionic triiminophosphonates [RP(NR′)3]2− and trianionic tetraiminophosphates [P(NR′)4]3−. Aza-phosphorus(V) ligands feature bridging PNP units, which include cyclic and polymeric phosphazenes [R2PN]n. Imino-aza- phosphorus(V) ligands containing both imino and aza functions include linear diiminodiphosphazenates [N{R2P(NR′)2}2]− and multianionic poly(imino) cyclophosphazeantes such as [N4{RP(NR′)}4]4− and [N3{P(NR′)2}3]6−. Imino-aza phosphorus(V) ligands are assembled of three basic building blocks: the cationic tetravalent phosphonium centre (P), the anionic divalent amido function (N) and the terminally arranged R-group. The overall negative charge Z of the resulting ligand system is equal to the difference between the number of P and the number of N-centres: Z=n(P)n(N). Imino-aza phosphorus(V) ligands are electron rich N-donor ligands which co-ordinate via both N(imino) and N(aza) functions and have been applied in numerous metal complexes in order to stabilise low coordination numbers, unusual oxidation states and bonding modes or serve as ligands in homogeneous catalysis. The R-group provides both steric bulk and solubility in non-polar solvents. Multianionic phosphazenates feature a polydentate ligand surface, which facilitates an extremely high metal load. PN units of iminophosphoranes and phosphazenes have acceptor properties and enhance the acidity of α-alkyl and ortho-aryl protons. Deprotonation of P-alkyl and P-aryl iminophosphoranes give ligand systems featuring C,N chelating sites, which are also discussed. 相似文献
6.
Reaction of diamine-bis(phenol) ligands containing a mixture of N-methyl and N,N′-dimethyl-N,N-bis(2-hydroxy-3,5-dimethylbenzyl)ethylenediamine, H2L1 and H2L3, with [Ti(OCHMe2)4 in absolute ethanol under reflux without exclusion of air and moisture gives [(L1)Ti (OEt–O–Ti(OEt)(L1)] (1). [(L3)Ti(OEt)–O–Ti(OEt)(L3)] (2) forms when the remaining solution containing [(L3)Ti(OEt)2] (3) (characterised by X-ray crystallography) is hydrolysed with H2O. For the N-methyl and N,N′-dimethyl ligand mixture H2L2 and H2L4, which contain tert-butyl groups on the ortho-positions of the aryl rings, [(L2)Ti(OEt)–O–Ti(OEt)(L2)] (4) forms much more slowly and [(L4)Ti(OEt)2] (5) does not hydrolyse when H2O is added. When the N-protonated ligand N,N-bis(2-hydroxy-3-methyl-5-tert-butylbenzyl)ethylenediamine, H2L5, is used, rapid hydrolysis to two isomers of [(L5)Ti(OEt–O–Ti(OEt)(L5)] (6) occurs without addition of water. For N,N-bis(2-hydroxy-3,5-di-tert-butylbenzyl)ethylenediamine, H2L6, hydrolysis to [(L6)Ti(OEt)–O–Ti(OEt)(L6)] (7) occurs slowly when H2O is added. For pendant NMe2 ligand N,N-dimethyl-N′,N′-bis(2-hydroxy-3-methyl-5-tert-butylbenzyl)ethylenediamine, H2L7, the hydrolysis reaction readily gives [(L7)Ti(OEt)–O–Ti(OEt)(L7)] (8) for which an X-ray crystal structure was obtained. The ortho-tert-butyl ligand derivative H2L8 formed a complex analysing as [(L8)Ti(OEt)–O–Ti(OEt)(L8)] (9) which could not be studied further due to insolubility. Pendant pyridine ligand N-(2-pyridylmethyl)-N,N-bis(2′-hydroxy-3′-methyl-5′-tert-butylbenzyl)amine, H2L9, apparently forms isomers of [(L9)Ti(OEt)–O–Ti(OEt)(L9)] and possibly [{(L9)Ti(O)}2] from [(L9)Ti(OEt)2] (10). The ortho-tert-butyl ligand derivative H2L10 formed [(L10)Ti(OEt)–O–Ti(OEt)(L10)] (11) for which an X-ray crystal structure was obtained. 相似文献
7.
A novel zinc(II) polymeric complex of the formula {[Zn(tyr)2(H2O)]H2O}n (1) containing l-tyrosine (tyr) was prepared in the crystalline form and characterized by X-ray diffraction, NIR–Vis–UV electronic and IR–FIR vibrational spectroscopy methods. Additionally, for the [Cu(tyr)2]n (2) polymer, the vibrational, electronic, EPR spectroscopic and magnetic properties were studied. l-tyrosine in coordination polymers acts as a N,O-bidendate ligand and presents exobidentate bridging with a μ-carboxyl group. The μ-carboxyl exobidentate bridging coordination mode leads to a one-dimensional chain structure. The ZnN2O3O′ chromophore has an elongated pseudo-octahedral geometry (1), whereas the CuN2O2O′ (2) chromophore presents a distorted square-pyramidal environment with τ = 0.19 around the Cu2+ ion. 相似文献
8.
9.
10.
Four new polymers, namely [Ni(-tsgluO)(2,4′-bipy)2(H2O)2]n·5nH2O (1), [Co(-tsgluO)(2,4′-bipy)2(H2O)2]n·5nH2O (2), [Ni(-tsgluO)(4,4′-bipy)]n·0.5nH2O (3), and [Co(-tsgluO)(4,4′-bipy)]n·0.5nH2O (4), where tsgluO2−=(+)-N-p-tolylsulfonyl-l-glutamate dianion, 2,4′-bipy=2,4′-bipyridine, and 4,4′-bipy=4,4'-bipyridine, have been prepared and structurally characterized. Compounds 1 and 2 are isostructural and mononuclear, and crystallize in the acentric monoclinic space group Cc, forming 1D chain structures. Compound 3 is also mononuclear, but crystallizes in the chiral space group P21, forming a homochiral 2D architecture. In contrast to the other complexes, compound 4 crystallizes in the space group P−1 and is composed of binuclear [Co2O6N2]n4− units, which give rise to a 2D bilayer framework. Moreover, compounds 1, 2, and 4 self-assemble to form 3D supramolecular structures through π-π stacking and hydrogen-bonding interactions, while compound 3 is further hydrogen-bonded to form 3D frameworks. We have demonstrated the influence of the central metal and bipyridine ligands on the framework chirality of the coordination complexes. 相似文献
11.
Iron and ruthenium classical and non-classical hydrides of the type [MH(N–N)P3]+ and [M(η2-H2)(N–N)P3]2+ {M = Fe, Ru; N–N = 2,2′-bipyridine (bpy), 1,10-phenanthroline (phen); P = phosphites} were reported in 2004 together with an evaluation of the pseudo-aqueous pKa values of the η2-H2 complexes. The non-classical hydrides, even if doubly charged, showed a relatively low acidity, their pKa values ranging between −5.4 and −4.3. Moreover, ruthenium(II) derivatives showed to be more acidic than the corresponding iron(II) complexes. Information about the structural and electronic proprieties of complexes of this type, which allowed to better understand the role of both the metal centres and the ancillary ligands in the acidity of the co-ordinated hydrogen molecule, was obtained on the basis of DFT B3LYP calculations. 相似文献
12.
Time-resolved luminescence bioassay technique using lanthanide complexes as luminescent probes/sensors has shown great utilities in clinical diagnostics and biotechnology discoveries. In this work, a novel terpyridine polyacid derivative that can form highly stable complexes with lanthanide ions in aqueous media, (4′-hydroxy-2,2′:6′,2′′-terpyridine-6,6′′-diyl) bis(methylenenitrilo) tetrakis(acetic acid) (HTTA), was designed and synthesized for developing time-resolved luminescence pH sensors based on its Eu3+ and Tb3+ complexes. The luminescence characterization results reveal that the luminescence intensity of HTTA–Eu3+ is strongly dependent on the pH values in weakly acidic to neutral media (pKa = 5.8, pH 4.8–7.5), while that of HTTA–Tb3+ is pH-independent. This unique luminescence response allows the mixture of HTTA–Eu3+ and HTTA–Tb3+ (the HTTA–Eu3+/Tb3+ mixture) to be used as a ratiometric luminescence sensor for the time-resolved luminescence detection of pH with the intensity ratio of its Tb3+ emission at 540 nm to its Eu3+ emission at 610 nm, I540 nm/I610 nm, as a signal. Moreover, the UV absorption spectrum changes of the HTTA–Eu3+/Tb3+ mixture at different pHs (pH 4.0–7.0) also display a ratiometric response to the pH changes with the ratio of absorbance at 290 nm to that at 325 nm, A290 nm/A325 nm, as a signal. This feature enables the HTTA–Eu3+/Tb3+ mixture to have an additional function for the pH detection with the absorption spectrometry technique. For loading the complexes into the living cells, the acetoxymethyl ester of HTTA was synthesized and used for loading HTTA–Eu3+ and HTTA–Tb3+ into the cultured HeLa cells. The luminescence imaging results demonstrated the practical utility of the new sensor for the time-resolved luminescence cell imaging application. 相似文献
13.
Three rhenium(IV) mononuclear compounds of formulae [ReCl4(biimH2)] · 2DMF (1), [ReCl4(pyim)] · DMF (2) and [ReCl4(bipy)] (3) (biimH2 = 2,2′-biimidazole, pyim = 2-(2′-pyridyl)imidazole, bipy = 2,2′-bipyridine and DMF = N,N-dimethylformamide) have been prepared and characterized. The crystal structure of 2 was determined by single crystal X-ray diffraction. Compound 2 crystallizes in the monoclinic system with P21/c as space group. The rhenium atom is six-coordinated by four Cl atoms and two nitrogen atoms from a bidentate pyim ligand [average values of Re–Cl and Re–N bonds lengths being 2.330(2) and 2.117(4) Å, respectively]. The magnetic properties were investigated from susceptibility measurements performed on polycrystalline samples of 1–3 in the temperature range 1.9–300 K. The magnetic behaviour found is typical of antiferromagnetically coupled systems, and they exhibit susceptibility maxima at 2.8 (1 and 2) and 5.6 K (3). Short ReIV–Cl?Cl–ReIV contacts through space account for the antiferromagnetic behaviour observed. 相似文献
14.
Konstantina E. Chrysomallidou Spyros P. Perlepes Aris Terzis Catherine P. Raptopoulou 《Polyhedron》2010
Reactions of malonic acid (H2mal) with PrCl3·6H2O afforded the known complex [Pr2(mal)3(H2O)6]n (1), and compounds [Pr2(mal)3(H2O)6]n·2nH2O (2·2nH2O), [PrCl(mal)(H2O)3]n·0.5nH2O (3·0.5nH2O) and [Pr(mal)(Hmal)(H2O)3]n·nH2O (4·nH2O) using various reaction ratios, reaction media (H2O, MeOH) and pH values. Analogous reactions with CeCl3·7H2O afforded compounds [Ce2(mal)3(H2O)6]n (5), [CeCl(mal)(H2O)3]n·nH2O (6·nH2O) and [Ce(mal)(Hmal)(H2O)3]n·nH2O (7·nH2O). Compounds 2·2nH2O and 3·0.5nH2O were characterized by X-ray crystallography, and 4–7 by microanalytical and spectroscopic data. The malonate(-2) ligand adopts three different coordination modes in the structures of 1–3, i.e., the μ2-κO:κO′:κO″ and the μ4-κ2O:κO′:κ2O″:κO? in 1 and 2 leading to a 3D network structure, and the μ3-κ2O:κO′:κ2O″:κO? in 3 promoting an 1D structure. The thermal decomposition of 1 and 3·0.5nH2O was monitored by TG/DTA and TG/DTG measurements. The structural features of 1–3 are discussed in terms of known malonato(-2) LnIII and CaII complexes. The bioinorganic chemistry relevance of our results is discussed. 相似文献
15.
Richard J. Bowen 《Journal of organometallic chemistry》2004,689(7):1230-1237
Treatment of (RH2C)2C5H3N-2,6 (R=SiMe3) with BunLi followed by addition of Me3SiCl gave the tetrasilyl pyridine derivative (R2HC)2C5H3N-2,6 1 in high yield. Further lithiation of 1 with BunLi and reaction of the intermediate with PhCN led to the new lithium-1-azaallyl [Li{N(R)C(Ph)C(R)(C5H3N-2,6)(CHR2)}]22, while metallation of the previously described di-lithium compounds [Li{N(R)C(R′)CH}2(C5H3-2,6)]Li(tmen)n (R=SiMe3, R′=But, n=1 or R=SiMe3, R′=Ph, n=2) with PdCl2(PhCN)2 yielded the novel metallacycles [Pd{{N(H)(R)C(R′)CH}{N(SiMe2CH2)C(R′)CH}C5H3N-2,6}] 3 (R′=But) and [Pd{{N(R)C(R′)CH}{N(R)(H)C(R′)CH}C5H3N-2,6}2] (R′=Ph) 4 in moderate to low yield. Compound 3 is unusual in being the first example of a crystallographically characterised PdNSiC heterocycle which is believed to be formed via an intramolecular CH-activation of a trimethylsilyl group by Pd(II). All four compounds were fully characterised by NMR-spectroscopy, microanalysis (not 4) and X-ray diffraction. 相似文献
16.
Two procedures for the synthesis of group 4 phosphaguanidine compounds M(R2PC{NR′}2)(NR″2)3 (M = Ti, Zr; R = Ph, Cy; R′ = iPr, Cy; R″ = Me, Et) are described. Spectroscopic characterization indicated symmetrical bonding of the phosphaguanidinate ligand in solution for the P-diphenyl derivatives whereas the P-dicyclohexyl analogs adopt a more rigid geometry with inequivalent Namidine substituents within the phosphaguanidinate ligand. X-ray diffraction studies show exclusively monomeric tbp metal centers for a series of derivatives, with a chelating phosphaguanidinate ligand that spans an axial and an equatorial position. Two different conformers have been identified in the solid-state that differ in the relative orientation of the phosphorus R2P–C substituents with respect to the equatorial plane of the tbp metal. The synthetic protocol was extended to the bimetallic complex, [PhP(C{NiPr}2Ti{NMe2}3)CH2–]2, which was characterized by crystallography as the meso-form. 相似文献
17.
A room temperature ionic liquid (IL) composed of a quaternary alkylphosphonium (trihexyltetradecylphosphonium, P66614+) and tetrakis(pentafluorophenyl)borate anion (TB−) was employed within a water|P66614TB (w|P66614TB or w|IL) biphasic system to evaluate cesium ion extraction in comparison to that with a traditional water|organic solvent (w|o) combination. 137Cs is a major contributor to the radioactivity of spent nuclear fuel as it leaves the reactor, and its extraction efficiency is therefore of considerable importance. The extraction was facilitated by the ligand octyl(phenyl)-N,N′-diisobutylcarbamoylphosphine oxide (CMPO) used in TRans-Uranium EXtraction processes and investigated through well established liquid|liquid electrochemistry. This study gave access to the metal ion to ligand (1:n) stoichiometry and overall complexation constant, β, of the interfacial complexation reaction which were determined to be 1:3 and 1.6 × 1011 at the w|P66614TB interface while the study at w|o elicited an n equal to 1 with β equal to 86.5. Through a straightforward relationship, these complexation constant values were converted to distribution coefficients, δα, with the ligand concentrations studied for comparison to other studies present in the literature; the w|o and w|IL systems gave δα of 2 and 8.2 × 107, respectively, indicating a higher overall extraction efficiency for the latter. For the w|o system, the metal ion-ligand stoichiometries were confirmed through isotopic distribution analysis of mass spectra obtained by the direct injection of an emulsified water–organic solvent mixture into an electron spray ionization mass spectrometer. 相似文献
18.
Chiral cyclopentadienyl ruthenium(II) complexes [CpRu(L1–L3)Cl] (5–7) have been prepared by reaction of [CpRu(PPh3)2Cl] with chiral P,P-ligands (1R,2R)-1,2-bis(diphenylphosphinamino)cyclohexane (L1), N,N′-[bis-(3,3′-bis-tert-butyl-5,5′-bis-methoxy-1,1′-biphenyl-2,2′-diyl)phosphite]-(1R,2R)-1,2-diaminocyclohexane (L2) and N,N′-[bis-(R)-1,1′-binaphtyl-2,2′-diyl)phosphite]-(1R,2R)-1,2-diaminocyclohexane (L3). The molecular structures of 5 and 6 have been determined by single-crystal X-ray analysis. Studies on catalytic activity of the cations derived from (5–7) by treatment with AgSbF6, are also reported. 相似文献
19.
Synthesis and reactions of heterodinuclear organopalladium complex having an unsymmetrical PN ligand
Nobuyuki Komine 《Journal of organometallic chemistry》2007,692(21):4486-4494
Novel heterodinuclear organopalladium complexes having an unsymmetrical PN ligand (Et2NC2H4PPh2-κ2N,P)RPd-MLn (MLn = Co(CO)4; R = Me (2a), Ph (2b), MLn = MoCp(CO)3; R = Ph (3b)) are synthesized by metathetical reactions of PdRX(Et2NC2H4PPh2-κ2N,P) (X = I, NO3) with Na+[MLn]−. Reversible dissociation of the Pd-N bond in 3b is revealed by variable temperature NMR studies. Reactions of 2a and 2b with CO yield corresponding acyl complexes (Et2NC2H4PPh2-κ2N,P)(RCO)Pd-Co(CO)4 (R = Me (5a), Ph (5b)). Rate of CO insertion for 2a and 2b is significantly faster than those for mononuclear methylpalladium complex, PdMeI(Et2NC2H4PPh2-κ2N,P) (1a), and methylpalladium-cobalt complex with a 1,2-bis(diphenylphosphino)ethane (dppe) ligand, (dppe-κ2P,P′)MePd-Co(CO)4 (6a). 5a smoothly reacts with nucleophiles such as diethylamine, methanol and benzenethiol to give corresponding amide, ester and thioester, respectively. These reactions of 5a are also significantly faster than those of corresponding mononuclear analogues and the similar heterodinuclear complexes with symmetrical bidentate ligands such as 1,2-bis(diphenylphosphino)ethane or N,N,N′,N′-tetramethylethylenediamine ligand. 相似文献
20.
Organotin(IV) complexes of [SnR(4−n)Cln] (n = 2, R = Me, nBu; n = 1, R = Ph) react with the bidentate pyridyl ligand 4,4′-di-tert-butyl-2,2′-bipyridine (bu2bpy) to give hexa-coordinated adducts with the general formula [SnR(4−n)Cln(bu2bpy)]. However, the reaction of these organotin(IV) complexes with the corresponding monodentate ligand 4-tert-butylpyridine (bupy) resulted in the formation of the hexa-coordinated complex [SnMe2Cl2(bupy)2] and the penta-coordinated complexes [SnR(4−n)Cln(bupy)] (n = 2, R = nBu; n = 1, R = Ph). Moreover, the reaction of the above organotin(IV) complexes with 4,4′-trimethylenedipyridine (tmdp) yields hexa-coordinated adducts with the general formula [SnR2Cl2(tmdp)] (R = Me, nBu) and the penta-coordinated complex [ClPh3Sn-μ-(tmdp)SnPh3Cl] in the solid state. The resulting complexes have been characterized by multinuclear NMR (1H, 13C, 119Sn) spectroscopy and elemental analysis. NMR data shows that the triphenyltin(IV) adducts are not stable in solution and dissociate to give tetra-coordinated tin(IV) complexes. The X-ray crystal structure determination of [SnMe2Cl2(bu2bpy)] reveals that the tin atom is hexa-coordinated in an octahedral geometry with a trans-[SnMe2] configuration. 相似文献