Silver(I) complex formation with cysteine, penicillamine, and glutathione.
Silver(I) complex formation with cysteine, penicillamine, and glutathione.
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DOI：
10.1021/ic400192c
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发表时间：
2013-04-15
影响因子：
4.6
通讯作者：
Wu Q
中科院分区：
文献类型：
--
作者：
Leung BO;Jalilehvand F;Mah V;Parvez M;Wu Q
用扩展X射线吸收精细结构（EXAFS）和~（109）Ag核磁共振谱技术研究了半胱氨酸（H_2Cys）、青霉胺（H_2Pen）和谷胱甘肽（H_3Glu）与银（I）在碱性水溶液中的络合作用。在0.1 mol·dm−3 Ag（I）溶液中，半胱氨酸和青霉胺形成的配合物，配体/Ag（I）（L/Ag）摩尔比从2.0增加到10.0。对于半胱氨酸系列溶液（pH 10 - 11），始终出现平均Ag-S键距2.45 ± 0.02 μ m，而对于青霉胺（pH 9），平均Ag-S键距从2.40逐渐增加到2.44 ± 0.02 μ m。浓缩的Ag（I）-半胱氨酸溶液（CAg（I）= 0.8 mol·dm-3，L/Ag = 2.2）的EXAFS和109 Ag NMR光谱显示平均Ag-S键距为2.47 ± 0.02 μ m，δ（109 Ag）= 1103 ppm，与主要的部分低聚AgS 3配位物质一致，而对于青霉胺（CAg（I）= 0.5 mol·dm-3，L/Ag = 2.0），平均Ag-S键距为2.40 ± 0.02 μ m，δ（109 Ag）= 922 ppm，表明单核AgS_2配位化合物占主导地位。对于Ag（I）-谷胱甘肽溶液（CAg（I）= 0.01 mol·dm−3，pH ~ 11），当L/Ag摩尔比为2.0 ~ 10.0时，平均Ag-S键距为2.36 ± 0.02 nm的单核AgS 2配位物种占主导地位。在pH ~ 10沉淀的银（I）-半胱氨酸化合物（NH 4）Ag 2（HCys）（Cys）·H2O（1）的晶体结构被解析，显示出AgS 3和AgS 3 N均与半胱氨酸配体配位的层状结构。对Ag（HPen）·H2O（2）晶体结构的重新测定证实了所提出的二配位AgS 2配位环境，以桥接聚合物缠绕链中的硫醇硫原子，形成双螺旋。通过对不同AgS 2、AgS 2（O/N）和AgS 3配位环境中Ag（I）与S-给体配体的晶体配合物的Ag-S键长的研究，结合109 Ag NMR化学位移的研究，对溶液中Ag（I）配位进行了归属。
The complex formation between silver(I) and cysteine (H2Cys), penicillamine (H2Pen) or glutathione (H3Glu) in alkaline aqueous solution was examined using extended X-ray absorption fine structure (EXAFS) and 109Ag NMR spectroscopic techniques. The complexes formed in 0.1 mol·dm−3 Ag(I) solutions with cysteine and penicillamine were investigated for ligand/Ag(I) (L/Ag) mole ratios increasing from 2.0 to 10.0. For the series of cysteine solutions (pH 10 - 11) a mean Ag-S bond distance 2.45 ± 0.02 Å consistently emerged, while for penicillamine (pH 9) the average Ag-S bond distance gradually increased from 2.40 to 2.44 ± 0.02 Å. EXAFS and 109Ag NMR spectra of a concentrated Ag(I)-cysteine solution (CAg(I) = 0.8 mol·dm−3, L/Ag = 2.2) showed the mean Ag-S bond distance 2.47 ± 0.02 Å and δ(109Ag) = 1103 ppm, consistent with prevailing, partially oligomeric AgS3 coordinated species, while for penicillamine (CAg(I) = 0.5 mol·dm−3, L/Ag = 2.0) the mean Ag-S bond distance 2.40 ± 0.02 Å and δ(109Ag) = 922 ppm indicate that mononuclear AgS2 coordinated complexes dominate. For Ag(I)-glutathione solutions (CAg(I) = 0.01 mol·dm−3, pH ~ 11), mononuclear AgS2 coordinated species with the mean Ag-S bond distance 2.36 ± 0.02 Å dominate for L/Ag mole ratios from 2.0 to 10.0. The crystal structure of the silver(I)-cysteine compound (NH4)Ag2(HCys)(Cys)·H2O (1) precipitating at pH ~ 10 was solved and showed a layer structure with both AgS3 and AgS3N coordination to the cysteinate ligands. A redetermination of the crystal structure of Ag(HPen)·H2O (2) confirmed the proposed digonal AgS2 coordination environment to bridging thiolate sulfur atoms in polymeric intertwining chains forming a double helix. A survey of Ag-S bond distances for crystalline Ag(I) complexes with S-donor ligands in different AgS2, AgS2(O/N) and AgS3 coordination environments was used, together with a survey of 109Ag NMR chemical shifts, to assist assignments of the Ag(I) coordination in solution.
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影响因子：
4.6
作者：
BAENZIGER, NC;STRUSS, AW
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4.6
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