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Andrew W. Maverick Damon R. Billodeaux Michael L. Ivie Frank R. Fronczek Emily F. Maverick 《Journal of inclusion phenomena and macrocyclic chemistry》2001,39(1-2):19-26
A structural study of internal (endo) and external (exo) coordination to cofacial binuclear complexes is reported.Cu2(NBA)2(NBAH2=3,3'-[2,7-naphthalenediylbis(methylene)]-bis(2,4-pentanedione)) is large enough to accommodate 2-methylpyrazine as an intramolecularly coordinated guest molecule Cu2(NBA)2((2Mepyz))4CH2Cl2Cu2C53H58N2O8Cl8, orthorhombic, space group Pnma (No. 62); a = 22.4674(11); b = 22.230(2); c = 11.4520(6) Å V = 5719.6(6) Å3 (at 100 K); Z = 4; R = 0.058; R
w = 0.167 for 344 parameters and 5339 reflections with I > 2(I). The Cu2(NBA)2(-(2-Mepyz)) molecules possess crystallographic m symmetry, with the CuCu vector (CuCu' 7.4801(8) Å) perpendicular to the mirror plane; this requires disorder in the 2-Mepyz guests. The two ``Cu(acac)2' moieties (acacH = 2,4-pentanedione) are not quite parallel (dihedral angle between (acac)2 planes = 3.93(7)circ), forming a slightly wider opening on the side of the methyl group in the 2-Mepyz guest. On the other hand, the cavity in Cu2(XBA)2 (XBAH2 = 3,3'-[1,3-phenylenebis(methylene)]-bis(2,4-pentanedione)) is smaller, so that CH3CN must bind externally.Cu2(XBA)2(CH3CN)21.5CH3CNH2O,Cu2C43H52.5N3.5O9, monoclinic, space group P21/c (No. 14); a = 11.7361(16); b = 14.197(3); c = 13.299(3) Å; = 92.22(2)^; V = 2214.3(7) Å3 (at 100 K); Z = 2; R = 0.044; R
w = 0.124 for 275 parameters and 4983 reflections with I > 2 (I). This structure contains centrosymmetric Cu2(XBA)2 units (CuCu' 4.8302(12) Å) with externally coordinated CH3CN ligands. The crystal packing in Cu2(NBA)2((2Mepyz))4CH2Cl2,which contains close contacts between layers of Cu2(NBA)2(-(2-Mepyz)) moieties, is also similar to that in three other crystalline host–guest adducts M2(NBA)2(-G). Cu2(XBA)2(CH3CN)21.5CH3-CNH2O does not contain similar layers of molecules, presumably because the adduct molecules do not have the same type of exposed flat surfaces. 相似文献
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Ivie L. Conlon Katie Konsein Yulemni Morel Alexandria Chan Steven Fletcher 《Tetrahedron letters》2019,60(37):150929
Recently, there has been an upsurge in the occurrence of the indazole motif in drug discovery. Accordingly, newer, milder and more efficient routes towards their synthesis have emerged in the literature. We recently reported the Mitsunobu-triggered cyclodehydration of salicylaldoximes to transient 1,2-benzisoxazoles, and salicylhydroxamic acids to their corresponding 3-hydroxybenzisoxazoles. We hypothesized subjecting ortho-aminobenzoximes to Mitsunobu conditions will likewise induce a cyclodehydration to deliver the corresponding 1H-indazoles. Indeed, secondary anilines afforded the predicted N1-substituted 1H-indazoles, and primary anilines, after activation with a Boc group, furnished the N1-Boc 1H-indazoles in good to excellent yields. This work further expands the chemical repertoire of the Mitsunobu reaction, representing its unprecedented use in the construction of the 1H-indazole nucleus. 相似文献
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Irradiation of acetone solutions of trans-chlordane (4a) and trans-nonachlor (4b) with UV light produces new half-cage photoisomers (5a or 6a and 5b or 6b, respectively) with bridging that differs from that of the photoisomers (2 and 8a) obtained from cis-chlordane (1b) and heptachlor epoxide (7). A new photoisomer (10) obtained from heptachlor epoxide is transformed into photoisomer 8a on further irradiation. Detailed PMR and 13C-NMR studies establish the structures of the new photoisomers and permit a decision between alternative formulations for the structures of the half-cage photoisomers of heptachlor epoxide and cis-chlordane, 相似文献
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A micellar electrokinetic chromatographic method using UV and (UV)LIF detection in-line was developed for the determination of aromatic constituents, mainly allylbenzenes in essential oils. The method optimization included the optimization of the composition of the separation electrolyte using ACN and urea to reduce retention factors and CaCl(2) to widen the migration time window. In addition, it was necessary to optimize the composition of the sample solution which included the addition of a neutral surfactant at high concentration. With the optimized method, the determination of minor constituents in essential oils was possible despite of the presence of a structurally related compound being in a molar ratio excess of 1000:1. The use of UV and LIF-detection in-line enabled the direct comparison of the two detection traces using an electrophoretic mobility x-axis instead of the normal time-based scale. This simplifies the assignment of signals and enhances repeatability. The method developed was successfully applied to the determination of minor and major constituents in herbal essential oils, some of them being forensically relevant as sources of precursors for synthetic drugs. 相似文献
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Radaram B Ivie JA Singh WM Grudzien RM Reibenspies JH Webster CE Zhao X 《Inorganic chemistry》2011,50(21):10564-10571
The synthesis, characterization, and water oxidation activity of mononuclear ruthenium complexes with tris(2-pyridylmethyl)amine (TPA), tris(6-methyl-2-pyridylmethyl)amine (Me(3)TPA), and a new pentadentate ligand N,N-bis(2-pyridinylmethyl)-2,2'-bipyridine-6-methanamine (DPA-Bpy) have been described. The electrochemical properties of these mononuclear Ru complexes have been investigated by both experimental and computational methods. Using Ce(IV) as oxidant, stoichiometric oxidation of water by [Ru(TPA)(H(2)O)(2)](2+) was observed, while Ru(Me(3)TPA)(H(2)O)(2)](2+) has much less activity for water oxidation. Compared to [Ru(TPA)(H(2)O)(2)](2+) and [Ru(Me(3)TPA)(H(2)O)(2)](2+), [Ru(DPA-Bpy)(H(2)O)](2+) exhibited 20 times higher activity for water oxidation. This study demonstrates a new type of ligand scaffold to support water oxidation by mononuclear Ru complexes. 相似文献
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Isopimpinellin Is Not Phototoxic in a Chick Skin Assay 总被引:1,自引:0,他引:1
Abstract— Synthetic isopimpinellin (5,8-dimethoxypsoralen), confirmed to contain as impurities only trace quantities at most of psoralen, bergapten (5-methoxypsoralen) and xanthotoxin (8-methoxypsoralen), is not phototoxic when tested in a chick skin bioassay system. These findings are at variance with earlier studies showing isopimpinellin to be phototoxic against chick skin and support the conclusion that isopimpinellin is photobiologically inactive. As recently proposed by others, the several reports of isopimpinellin photoactivity are most likely attributable to contamination by small amounts of highly active psoralens such as bergapten or xanthotoxin. 相似文献
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Yen YF Brinkmöller B Dehnhard D Sterbenz SM Yu YJ Berman B Burleson GR Cranston K Klein A Kyle GS Alarcon R Averett T Comfort JR Görgen JJ Ritchie BG Tinsley JR Barlett M Hoffmann GW Johnson K Moore CF Purcell M Ward H Williams A Faucett JA Greene SJ Jarmer JJ McGill JA Morris CL Penttilä S Tanaka N Fortune HT Insko E Ivie R O'Donnell JM Smith D Khandaker MA Chakravarti S 《Physical review letters》1991,66(15):1959-1962
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