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1.
Santana MD García G Lozano AA López G Tudela J Pérez J García L Lezama L Rojo T 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(7):1738-1746
The bis(phosphatediester)-bridged complexes [[Ni([12]aneN(3))(mu-O(2)P(OR)(2))](2)](PF(6))(2) [[12]aneN(3)=Me(3)[12]aneN(3), 2,4,4-trimethyl-1,5,9-triazacyclododec-1-ene; R=Me (1), Bu (2), Ph (3), Ph-4-NO(2) (4); [12]aneN(3)=Me(4)[12]aneN(3), 2,4,4,9-tetramethyl-1,5,9-triazacyclododec-1-ene; R=Me (5), Bu (6), Ph (7), Ph-4-NO(2) (8)] were prepared by hydrolysis of the phosphate triester with the hydroxo complex [[Ni([12]aneN(3))(mu-OH)](2)](PF(6))(2) or by acid-base reaction of the dialkyl or diaryl phosphoric acid and the above hydroxo complex. The acid-base reaction was also used to synthesise the phosphinate-bridged complexes [[Ni([12]aneN(3))(mu-O(2)PR(2))](2)](PF(6))(2) [[12]aneN(3)=Me(3)[12]aneN(3), R=Me (9), Ph (10); [12]aneN(3)=Me(4)[12]aneN(3), R=Me (11), Ph (12)]. The molecular structures of complexes 2, 3 and 12 were established by single crystal X-ray diffraction studies. The eight-membered rings defined by the nickel atoms and the bridging ligands show distorted twist-boat, chair and boat-boat conformations in 2, 3 and 12, respectively. The experimental susceptibility data for compounds 2, 3 and 12 were fitted by least-squares methods to the analytical expression given by Ginsberg. The best fit was obtained with values of J=-0.11 cm(-1), D=-9.5 cm(-1) and g=2.20 for 2; J=-0.97 cm(-1), D=-9.3 cm(-1) and g=2.21 for 3; and J=-0.14 cm(-1), D=-11.9 cm(-1) and g=2.195 for 12. The magnetic-exchange pathways must involve the phosphate/phosphinate bridges, because these favour antiferromagnetic interactions. The observation of a higher exchange parameter for compound 3 is a consequence of a favourable disposition of the O-P-O bridges. The kinetics for the hydrolysis of TNP (tris(4-nitrophenyl)phosphate) with the dinuclear nickel(II) hydroxo complex [[Ni(Me(3)[12]aneN(3))(mu-OH)](2)](PF(6))(2) was studied by UV-visible spectroscopy. The proposed mechanism for TNP-promoted hydrolysis can be described as one-substrate/two-product, and can be fitted to a Michaelis-Menten equation. 相似文献
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Phosphinic and phosphonic acids are useful intermediates and biologically active compounds which may be prepared from their esters, phosphinates and phosphonates, respectively, by hydrolysis or dealkylation. The hydrolysis may take place both under acidic and basic conditions, but the C-O bond may also be cleaved by trimethylsilyl halides. The hydrolysis of P-esters is a challenging task because, in most cases, the optimized reaction conditions have not yet been explored. Despite the importance of the hydrolysis of P-esters, this field has not yet been fully surveyed. In order to fill this gap, examples of acidic and alkaline hydrolysis, as well as the dealkylation of phosphinates and phosphonates, are summarized in this review. 相似文献
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C. Dennis Hall Peter Speers Rosa Valero Francisco Perez Pla Donald B. Denney 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4):143-146
Abstract The reaction of triphenylphosphonium cyclopentadienylide (1) with halogen-substituted p-benzoquinones (4) is shown to give a new class of dipolar (zwitterionic) dyes (5) containing phosphorus. The general structure of these molecules has been investigated by a combination of mass spectrometry and multinuclear (1H, l3C and 3lP) nmr using the specialist techniques of DEPT spectroscopy, homonuclear (COSY) and heteronuclear, 2-D nmr. In addition, stopped-flow (uv/vis) techniques have been used to study the kinetics of the reactions and hence demonsrate that the rate-limiting step is nucleophilic addition of the ylid to the quinone, followed by a rapid loss of halide ion. The mechanism follows the classical pattern associated with nucleophilic aromatic substitution in activated aryl halides. 相似文献
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Akari Kawajiri Dr. Taro Udagawa Prof.Dr. Mao Minoura Prof.Dr. Toshiaki Murai 《ChemistryOpen》2022,11(11)
The substitution reaction of phosphinates with a binaphthyloxy group at the phosphorus atom with lithium alkoxides proceeded with good to high efficiencies to give P‐chirogenic phosphinates with a high enantiomeric ratio. As alcohols, primary, secondary, and tertiary alcohols could be used, and the use of tert‐butyl alcohol yielded the products with a higher enantiomeric ratio. A substrate with two different alkyl groups on the phosphorus atom could also participate in the substitution reaction to give the corresponding products in good yields with excellent selectivity. The molecular structures of one of the substrates and the corresponding products, determined by X‐ray analyses, proved that the substitution reaction at the phosphorus atom proceeded with inversion of the absolute configuration. The usefulness of the reaction was demonstrated by using it to prepare a drug candidate for Duchenne muscular dystrophy. Finally, thionation of the resulting phosphinates was carried out to form P‐chirogenic phosphinothioates. 相似文献
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T. A. Mastryukova O. I. Artyushin M. P. Pasechnik E. V. Sharova I. L. Odinets V. P. Morgalyuk I. G. Tananaev G. V. Myasoedova B. F. Myasoedov 《Russian Chemical Bulletin》2005,54(11):2540-2544
The composition of complexes formed upon the extraction of UVI and ThIV nitrates with O-n-nonyl(N,N-dibutylcarbamoylmethyl) methyl phosphinate (L) from solutions of nitric acid without additional solvent was determined by 31P NMR spectroscopy. The structures of the complexes formed were studied by IR spectroscopy. Uranium(VI) is extracted from 3 and 5 M solutions of HNO3 as the [UO2(L)2(NO3)2] complex, while thorium(IV) is extracted from 5 M HNO3 as the [Th(L)3(NO3)3]+·NO
3
−
complex. In both cases, ligand L has bidentate coordination. Ligand L contacts with 3 and 5 M nitric acid to form adducts L·HNO3 and L· (HNO3)2, respectively.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2460–2464, November, 2005. 相似文献
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Chemoselective Activation of Diethyl Phosphonates: Modular Synthesis of Biologically Relevant Phosphonylated Scaffolds 下载免费PDF全文
Dr. Pauline Adler Dr. Amandine Pons Dr. Jing Li Jörg Heider Bogdan R. Brutiu Prof. Dr. Nuno Maulide 《Angewandte Chemie (International ed. in English)》2018,57(40):13330-13334
Phosphonates have garnered considerable attention for years owing to both their singular biological properties and their synthetic potential. State‐of‐the‐art methods for the preparation of mixed phosphonates, phosphonamidates, phosphonothioates, and phosphinates rely on harsh and poorly selective reaction conditions. We report herein a mild method for the modular preparation of phosphonylated derivatives, several of which exhibit interesting biological activities, that is based on chemoselective activation with triflic anhydride. This procedure enables flexible and even iterative substitution with a broad range of O, S, N, and C nucleophiles. 相似文献
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Qiuli Yao Prof. Dr. Chengye Yuan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(19):6080-6088
A highly enantioselective synthesis of α‐hydroxyphosphinates was achieved based on the L ‐proline‐catalyzed aldol reaction of α‐acylphosphinates and acetone. Due to the preexisting chirality at the phosphorus center, mixtures of two diastereomers of the α‐hydroxyphosphinates were obtained in moderate to good yields, with simultaneously high enantioselectivity for both diastereomers. The products could be converted into α‐hydroxy‐H‐phosphinates with satisfactory yields. Furthermore, an unprecedented oxidation–reduction reaction of the α‐hydroxyphosphinates or α‐hydroxy‐H‐phosphinates to form phosphonates was observed, and the mechanism involved in such a chemical transformation is discussed. 相似文献