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51.
Heroux KJ Woodin KS Tranchemontagne DJ Widger PC Southwick E Wong EH Weisman GR Tomellini SA Wadas TJ Anderson CJ Kassel S Golen JA Rheingold AL 《Dalton transactions (Cambridge, England : 2003)》2007,(21):2150-2162
A cross-bridged cyclam ligand bearing two N-carboxymethyl pendant arms (1) has been found to form a copper(II) complex that exhibits significantly improved biological behavior in recent research towards (64)Cu-based radiopharmaceuticals. Both the kinetic inertness and resistance to reduction of Cu-1 are believed to be relevant to its enhanced performance. To explore the influence of pendant arm length on these properties, new cross-bridged cyclam and cyclen ligands with longer N-carboxyethyl pendant arms, 2 and 4, and their respective copper(II) complexes have been synthesized. Both mono- as well as di-O-protonated forms of Cu-2 have also been isolated and structurally characterized. The spectral and structural properties of Cu-2 and Cu-4, their kinetic inertness in 5 M HCl, and electrochemical behavior have been obtained and compared to those of their N-carboxymethyl-armed homologs, Cu-1 and Cu-3. Only the cyclam-based Cu-1 and Cu-2 showed unusually high kinetic inertness towards acid decomplexation. While both of these complexes also exhibited quasi-reversible Cu(II)/Cu(I) reductions, Cu-2 is easier to reduce by a substantial margin of +400 mV, bringing it within the realm of physiological reductants. Similarly, of the cyclen-based complexes, Cu-4 is also easier to reduce than Cu-3 though both reductions are irreversible. Biodistribution studies of (64)Cu-labeled 2 and 4 were performed in Sprague Dawley rats. Despite comparable acid inertness to their shorter-armed congeners, both longer-armed ligand complexes have poorer bio-clearance properties. This inferior in vivo behavior may be a consequence of their higher reduction potentials. 相似文献
52.
Abby R O'Connor Chip Nataro James A Golen Arnold L Rheingold 《Journal of organometallic chemistry》2004,689(14):2411-2414
A new chemical oxidant [N(4-C6H4Br)3][B(C6F5)4], was prepared and used to synthesize [Fe(C5H5)2][B(C6F5)4]. The crystal structure of [Fe(C5H5)2][B(C6F5)4] was determined. 相似文献
53.
Hughes RP Ward AJ Golen JA Incarvito CD Rheingold AL Zakharov LN 《Dalton transactions (Cambridge, England : 2003)》2004,(17):2720-2727
A series of palladium(II) and platinum(II) complexes possessing pentafluorophenyl ligands of the general formula [M(L-L)(C6F5)Cl][space](M = Pd 3; L-L=tmeda (N,N,N',N',-tetramethylethylenediamine) a; 1,2-bis(2,6-dimethylphenylimino)ethane) b; dmpe (1,2-bis(dimethylphosphino)ethane) c; dcpe (1,2-bis(dicyclohexylphosphino)ethane) d; Pt ; L-L=tmeda a; 1,2-bis[3,5-bis(trifluoromethyl)phenylimino]-1,2-dimethylethane b; dmpe c; dcpe d) were readily synthesized from the dimer [M(C6F5)(tht)(mu-Cl)2] (M=Pd 1b, Pt 2b; tht=tetrahydrothiophene) and the corresponding bidentate ligand. In the case of palladium, the corresponding iodo analogues (6a-c) were readily synthesized in a one-pot reaction from [Pd2(dba)3], iodopentafluorobenzene, and the appropriate ligand. The platinum complexes 4c-d were then converted to the water complexes [Pt(L-L)(C6F5)(OH2)]OTf (L-L =dmpe 7a; dcpe 7b)via reaction with AgOTf in the presence of water. Attempts to convert the palladium complexes 3c-d to the corresponding water complexes resulted in the disproportionation of the intermediate water complex to form [Pd(L-L)(C6F5)2] (L-L=dmpe 8) or [Pd(L-L)2][OTf]2(L-L=dcpe 9). Upon standing in solution for prolonged periods, complex 7a undergoes an identical disproportionation reaction to the Pd analogues to form [Pt(L-L)(C6F5)2] (L-L=dmpe 10). Complexes 4c and 4d were converted to the corresponding hydrides (11b-c, respectively) using two different hydride sources: 11a was formed by the reaction of with NaBH4 in refluxing THF, while 11b was synthesized in near quantitative yield using [Cp2ZrH2] in refluxing THF. Attempts to synthesize eta2-tetrafluorobenzyne complexes [Pt(L-L)(C6F4)] (L-L=dmpe, dcpe) from reaction of 11a-b with butyllithium were unsuccessful. The molecular structures of 3a,4a, 4c, 4d, 6b, 7a, 8, 11b and have been determined by X-ray crystallographic studies, and are discussed. 相似文献
54.
U. Ibotomba Singh R. K. Bhubon Singh M. J. Borah J. P. Jasinski J. A. Golen 《Journal of Structural Chemistry》2013,54(1):116-122
A new monoclinic Cu(II) salt complex (C6H6N2) 2 + [Cu(2,6-dipico)2]2?·6H2O, (2,6-dipico=pyridine-2,6-dicarboxylic acid) is synthesized and characterised by CHN analyses, IR, UV-Vis, magnetic susceptibility measurements, and single crystal X-ray crystallography. The structure contains two pyridine-2,6-dicarboxylate species as tridentate ligands with protonated aniline acting as a counter cation and six uncoordinated water molecules. The complex crystallizes in the monoclinic space group C2/c with unit cell parameters a = 20.9393(4) Å, b = 7.94330(10) Å, c = 19.9093(4) Å, V(Å3) = 2932.32(9), Z = 4. Crystal packing is stabilized by N-H…O, O-H…O intermolecular hydrogen bonds and weak π…π interactions. The water molecules are trapped by a cooperative association of coordination interactions forming water clusters as well as by a hydrogen bond to the Cu (II) complex. 相似文献
55.
This paper obtains solitons as well as other solutions to a few nonlinear evolution equations that appear in various areas of mathematical physics. The two analytical integrators that are applied to extract solutions are tan–cot method and functional variable approaches. The soliton solutions can be used in the further study of shallow water waves in (1+1) as well as (2+1) dimensions. 相似文献
56.
Mehrdad Pourayoubi Atekeh Tarahhomi Arnold L. Rheingold James A. Golen 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(10):998-1002
In N,N,N′,N′‐tetraethyl‐N′′‐(4‐fluorobenzoyl)phosphoric triamide, C15H25FN3O2P, (I), and N‐(2,6‐difluorobenzoyl)‐N′,N′′‐bis(4‐methylpiperidin‐1‐yl)phosphoric triamide, C19H28F2N3O2P, (II), the C—N—C angle at each tertiary N atom is significantly smaller than the two P—N—C angles. For the other new structure, N,N′‐dicyclohexyl‐N′′‐(2‐fluorobenzoyl)‐N,N′‐dimethylphosphoric triamide, C21H33FN3O2P, (III), one C—N—C angle [117.08 (12)°] has a greater value than the related P—N—C angle [115.59 (9)°] at the same N atom. Furthermore, for most of the analogous structures with a [C(=O)NH]P(=O)[N(C)(C)]2 skeleton deposited in the Cambridge Structural Database [CSD; Allen (2002). Acta Cryst. B 58 , 380–388], the C—N—C angle is significantly smaller than the two P—N—C angles; exceptions were found for four structures with the N‐methylcyclohexylamide substituent, similar to (III), one structure with the seven‐membered cyclic amide azepan‐1‐yl substituent and one structure with an N‐methylbenzylamide substituent. The asymmetric units of (I), (II) and (III) contain one molecule, and in the crystal structures, adjacent molecules are linked via pairs of N—H...O=P hydrogen bonds to form dimers. 相似文献
57.
Childress MV Millar D Alam TM Kreisel KA Yap GP Zakharov LN Golen JA Rheingold AL Doerrer LH 《Inorganic chemistry》2006,45(10):3864-3877
Two thallium aryloxide compounds TlOC6F5 (TlOAr(F)) and bis-3,5-TlOC6H3(CF3)2 (TlOAr') have been recrystallized from THF and crystallographically characterized in different isomeric forms. The latter compound forms a solvated tetrameric cubane, [TlOAr']4.THF, 1. The TlOAr(F) compound crystallized with a similar stoichiometry, [TlOAr(F)]4.2 THF, 2, but contains a [Tl2(mu2-OAr(F))4] unit that includes a thallophilic interaction at a distance of 3.5943(15) angstroms. Solution 205Tl and 203Tl NMR studies of 1 and 2 support the retention of a cubane structure for 1 in solution and suggest a similar structure for 2 with coupled thallium centers down to -90 degrees C. Fluorescence spectroscopy data for both compounds 1 and 2 in THF are consistent with LMCT. DFT calculations of 1, 2, and three models of the [Tl2(mu2-OAr(F))4] unit show a bonding overlap of the bridged thallium atoms in 2 and are also used to describe the bonding in 1. The structures of two heterobimetallic compounds, Tl2Cu(OAr(F))4, 4, and Tl2Cu(OAr')4, 5, with the [Tl2(mu2-OAr(F))4] structural motif and thallophilic contacts of 3.86(6) and 3.564(1) angstroms, respectively, are described. The crystal structures of the unsolvated of TlOAr(F), 2b, solvated heterobimetallic derivative Tl2Cu(OAr')4.2THF, 5b, and the monomeric (18-crown-6)TlOAr(F), 3, and 205Tl NMR spectra of TlOC6H5, 6, are also reported for comparison purposes. 相似文献
58.
Mitchell A. Pet Russell P. Hughes James A. Golen 《Journal of organometallic chemistry》2009,694(14):2279-5343
Syntheses of the known ferrocenylmethylphosphines FcCH2PH2 (2, Fc = (η5-C5H4)Fe(η5-C5H5)), (FcCH2)2PH (3), and (FcCH2)3P (4) have been reinvestigated. The reaction of [FcCH2NMe3][I] with P(CH2OH)3, generated from [P(CH2OH)4][Cl] and KOH, gave a mixture of the major product (FcCH2)P(CH2OH)2 (1) and over-alkylated (FcCH2)2P(CH2OH) (9). Treatment of pure 9 with Na2S2O5 gave the secondary phosphine 3; slow addition of Na2S2O5 to 1 gave 2 in improved yield. Reaction of 1 with [FcCH2NMe3][I], followed by treatment with NEt3, gave the tertiary phosphine (FcCH2)3P (4), along with the known phosphonium salt [(FcCH2)4P][I] (5), which could be prepared in higher yield by adjusting the stoichiometry. Phosphine 4 oxidized slowly in air to yield (FcCH2)3P(O) (12), was protonated by HBF4(OMe2) to give [(FcCH2)3PH][BF4] (13), and reacted with Pt(COD)Cl2 or PtCl2 to yield a mixture of cis- and trans-Pt(P(CH2Fc)3)2Cl2 (14). Silylation of 2 with n-BuLi/Me3SiCl gave FcCH2P(SiMe3)2 (10); treatment of 1 with Me3SiCl/Et3N gave FcCH2P(CH2OSiMe3)2 (11). The phosphine-borane adducts FcCH2PH2(BH3) (6), (FcCH2)2PH(BH3) (7), (FcCH2)3P(BH3) (8) and (FcCH2)P(CH2OSiMe3)2(BH3) (15) were prepared from the corresponding phosphines and BH3(SMe2). The phosphines 2, 3, and 4, phosphonium salts 5 and 13, phosphine oxide 12, Pt complex trans-14, and phosphine-boranes 6, 7 and 8 were structurally characterized by X-ray crystallography. The solid cone angle of (FcCH2)3P, 139°, in Pt complex 14 showed that 4 was bulkier than PPh3, but less sterically demanding than P(t-Bu)3. The structural changes observed on quaternization of P (shorter P-C bonds and larger angles at P), along with results from NMR and IR spectroscopy and DFT calculations, were consistent with the expected rehybridization at phosphorus. Related observations for analogous methylphosphines suggest that methyl and ferrocenylmethyl phosphorus substituents have similar properties. 相似文献
59.
Duyen N. K. Pham Mrittika Roy Ava Kreider-Mueller James A. Golen David R. Manke 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(5):568-574
Seven crystal structures of five first‐row (Fe, Co, Ni, Cu, and Zn) and one second‐row (Cd) transition metal–4‐picoline (pic)–sulfate complexes of the form [M(pic)x]SO4 are reported. These complexes are catena‐poly[[tetrakis(4‐methylpyridine‐κN)metal(II)]‐μ‐sulfato‐κ2O:O′], [M(SO4)(C6H7N)4]n, where the metal/M is iron, cobalt, nickel, and cadmium, di‐μ‐sulfato‐κ4O:O‐bis[tris(4‐methylpyridine‐κN)copper(II)], [Cu2(SO4)2(C6H7N)6], catena‐poly[[bis(4‐methylpyridine‐κN)zinc(II)]‐μ‐sulfato‐κ2O:O′], [Zn(SO4)(C6H7N)2]n, and catena‐poly[[tris(4‐methylpyridine‐κN)zinc(II)]‐μ‐sulfato‐κ2O:O′], [Zn(SO4)(C6H7N)3]n. The Fe, Co, Ni, and Cd compounds are isomorphous, displaying polymeric crystal structures with infinite chains of MII ions adopting an octahedral N4O2 coordination environment that involves four picoline ligands and two bridging sulfate anions. The Cu compound features a dimeric crystal structure, with the CuII ions possessing square‐pyramidal N3O2 coordination environments that contain three picoline ligands and two bridging sulfate anions. Zinc crystallizes in two forms, one exhibiting a polymeric crystal structure with infinite chains of ZnII ions adopting a tetrahedral N2O2 coordination containing two picoline ligands and two bridging sulfate anions, and the other exhibiting a polymeric crystal structure with infinite chains of ZnII ions adopting a trigonal bipyramidal N3O2 coordination containing three picoline ligands and two bridging sulfate anions. The structures are compared with the analogous pyridine complexes, and the observed coordination environments are examined in relation to crystal field theory. 相似文献
60.
Hughes RP Laritchev RB Yuan J Golen JA Rucker AN Rheingold AL 《Journal of the American Chemical Society》2005,127(43):15020-15021
Primary perfluoroalkyl compounds of iridium undergo facile two-electron reduction to afford a simple route to difluorocarbene and perfluoroalkylidene complexes, two of which have been crystallographically characterized. Low-temperature protonation reactions illustrate that the thermodynamic site of protonation depends on the nature of the fluorinated carbene; the difluorocarbene complex undergoes protonation at iridium, while its perfluoroethylidene congener undergoes protonation at carbon. 相似文献