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1.
The reaction of the aryl‐oxide ligand H2L [H2L = N,N‐bis(3, 5‐dimethyl‐2‐hydroxybenzyl)‐N‐(2‐pyridylmethyl)amine] with CuSO4 · 5H2O, CuCl2 · 2H2O, CuBr2, CdCl2 · 2.5H2O, and Cd(OAc)2 · 2H2O, respectively, under hydrothermal conditions gave the complexes [Cu(H2L1)2] · SO4 · 3CH3OH ( 1 ), [Cu2(H2L2)2Cl4] ( 2 ), [Cu2(H2L2)2Br4] ( 3 ), [Cd2(HL)2Cl2] ( 4 ), and [Cd2(L)2(CH3COOH)2] · H2L ( 5 ), where H2L1 [H2L1 = 2, 4‐dimethyl‐6‐((pyridin‐2‐ylmethylamino)methyl)phenol] and H2L2 [H2L2 = 2‐(2, 4‐dimethyl‐6‐((pyridin‐2‐ylmethylamino)methyl)phenoxy)‐4, 6‐dimethylphenol] were derived from the solvothermal in situ metal/ligand reactions. These complexes were characterized by IR spectroscopy, elementary analysis, and X‐ray diffraction. A low‐temperature magnetic susceptibility measurement for the solid sample of 2 revealed antiferromagnetic interactions between two central copper(II) atoms. The emission property studies for complexes 4 and 5 indicated strong luminescence emission.  相似文献   

2.
The β‐diketonate derivative ligand [H2L = 6‐(3‐hydroxy‐1‐oxo‐3‐pyrryl‐2‐propen‐1‐yl)‐2‐pyridinecarboxylic acid] and its zinc(II) coordination complexes, [Zn(H2L)Cl2] · (EtOH)(H2O) ( 1 ) and [Zn4(L)4(H2O)2] · 5H2O ( 2 ), were prepared and characterized by elemental analysis, IR and NMR spectroscopy, and single‐crystal X‐ray diffraction. Complex 1 is a mononuclear structure. Complex 2 is a [2 × 2] grid tetranuclear structure. The luminescent properties of the free ligand H2L and complexes 1 and 2 in methanol solution were studied.  相似文献   

3.
Two cadmium(II) and two zinc(II) coordination complexes with diverse structural motifs, [Cd2(HL)I3H2O] · H2O ( 1 ), [Cd2(H2L)2(H2O)4] · 2SO4 · 14H2O ( 2 ), [Zn3(L′)2(H2O)6] · 4H2O · 2(NO3) ( 3 ), and [Zn3L'2(H2O)2Cl2] · H2O ( 4 ) [H2L = 1,1‐bis(5‐(pyrid‐2‐yl)‐1,2,4‐triazol‐3‐yl)methane; H2L′ = 1,1‐bis(5‐(pyrid‐2‐yl)‐1,2,4‐triazol‐3‐yl)methanone] were synthesized through a hydrothermal method. These coordination complexes were characterized by single‐crystal X‐ray diffraction, powder X‐ray diffraction (PXRD), FT‐IR spectroscopy, and photo‐luminescent experiments. Single crystal structural analysis revealed that 1 – 4 belong to polynuclear coordination compounds. PXRD analysis of 1 – 4 unambiguously confirmed the purity of the as‐synthesized coordination compounds. It is the first time to synthesize coordination compounds based on H2L′, which reacted from the original material H2L through in‐situ hydrothermal conditions. In addition, photo‐luminescent experiments revealed that 1 – 4 have real‐time sensing effects for benzaldehyde through fluorescence quenching. For 1 – 4 , the photo‐luminescent quenching effect for benzaldehyde was also compared and the coordination complexes 3 and 4 based on H2L′ have higher photo‐luminescent quenching effect than compounds 1 and 2 .  相似文献   

4.
Sodium in dry methanol reduces 2‐cyanopyridine in the presence of 3‐hexamethyleneiminylthiosemicarbazide and produces 2‐pyridineformamide 3‐hexamethyleneiminylthiosemicarbazone, HAmhexim ( 1 ). Complexes with zinc(II ), cadmium(II ) and mercury(II ) have been prepared and characterized by spectroscopic techniques. In addition, the crystal structures of HAmhexim ( 1 ), [Zn(Amhexim)(OAc)]2μ·μDMSO ( 2 ), [Cd(HAmhexim)Cl2]μ·μDMSO ( 7 ), [Cd(Amhexim)2] ( 8 ), [Cd(HAmhexim)Br2]μ·μDMSO ( 9 ), [Cd(HAmhexim)I2]μ·μEtOH ( 10 ), [Hg(HAmhexim)Cl2]μ·μDMSO ( 11 ), [Hg(Amhexim)Br]2 ( 13 ), [Hg3(HAmhexim)(Amhexim)Br5]μ·μH2O ( 14 ) and [Hg(Amhexim)I]2 ( 15 ) have been determined. Coordination of the anionic and neutral thiosemicarbazone ligand occurs through the pyridine nitrogen atom, imine nitrogen atom, and thiolato or thione sulfur atom. In [Zn(Amhexim)(OAc)]2 one of the bridging acetato ligands has monodentate coordination and the other bridges in a bidentate manner. [Cd(Amhexim)2] is a 6‐coordinate species while the other cadmium complexes are 5‐coordinate. In [Hg(Amhexim)Br]2 and [Hg(Amhexim)I]2 the thiolato sulfur atoms act as bridges between the Hg atoms to form dimeric compounds and [Hg3(HAmhexim)(Amhexim)Br5]μ·μH2O is a trinuclear complex with three different centers — two metallic centers have a 5‐coordination and the another one has 4‐coordination. In addition, [Hg(HAmhexim)Cl2]μ·μDMSO and [Hg3(HAmhexim)(Amhexim)Br5]μ·μH2O shown a supramolecular one‐dimensional hydrogen‐bonded self‐assembling.  相似文献   

5.
Synthesis and Crystal Structure of Ammine(μ3‐L‐glutamato)copper(II) [Cu(L‐Glu)H2O]·H2O reacts with aqueous ammonia to give the ammine complex [Cu(L‐Glu)NH3] ( 1 ). 1 forms orthorhombic crystals, space group P 21212 with a = 1585,1(1) pm; b = 979,46(7) pm and c = 504,70(5) pm. In the crystal structure of 1 the copper atoms are linked by μ3‐glutamate units to give a 2D layer structure. The copper atoms exhibit a square‐pyramidal coordination with two N atoms and two O atoms in the base plane and one O atom at the apex of the pyramid. The crystal structure is stabilized by a 3D network of N–H···O hydrogen bridges.  相似文献   

6.
Reduction of 2‐cyanopyridine by sodium in the presence of 3‐hexamethyleneiminylthiosemicarbazide produces 2‐pyridineformamide 3‐hexamethyleneiminylthiosemicarbazone, HAmhexim. Complexes with nickel(II), copper(II) and palladium(II) have been prepared and the following complexes structurally characterized: [Ni(Amhexim)OAc], [{Cu(Amhexim)}2C4H4O4]·2DMSO·H2O, [Cu(HAmhexim)Cl2] and [Pd(Amhexim)Cl]. Coordination is via the pyridyl nitrogen, imine nitrogen and thiolato or thione sulfur atom when coordinating as the anionic or neutral ligand, respectively. [{Cu(Amhexim)}2C4H4O4] is a binuclear complex with the two copper(II) ions bridged by the succinato group in [Cu‐(HAmhexim)Cl2] the Cu atom is 5‐coordinate and close to a square pyramid structure and in [Ni(Amhexim)OAc] and [Pd(Amhexim)Cl] the metal atoms are planar, 4‐coordinate.  相似文献   

7.
Four complexes with supramolecular architectures, namely, MZCA · 3H2O ( 1 ), [Zn(H2O)6]2+ · [MZCA]2 · [H2O]6 ( 2 ), [Mn(MZCA)2(H2O)4] · 2H2O ( 3 ), and [Ni(MZCA)2(H2O)4] · 2H2O ( 4 ) [MZCA = 3‐(carboxymethyl)‐2, 7‐dimethyl‐3H‐benzo[d]imidazole‐5‐carboxylic acid], were synthesized and characterized by elemental analysis, IR spectroscopy, and single‐crystal X‐ray diffraction. Complexes 1 and 2 display a remarkable 3D network with 1D hydrophilic channels. Complexes 3 and 4 are isostructural and exhibit a 3D structure encapsulating 1D 24‐membered ring microporous channels. The UV/Vis and fluorescent spectra were measured to characterize complexes 1 – 4 . The thermal stability of complexes 2 – 4 were also examined.  相似文献   

8.
Thiosemicarbazone ligand, 2‐((4,9‐dimethoxy‐5‐oxo‐5H‐furo[3,2‐g]chromen‐6‐yl)methylene) hydrazinecarbothioamide and its Cd(II), Cu(II), Zn(II), Ni(II), Co(II), VO(II), and Mn(II) complexes have been prepared and characterized by various spectroscopic and analytical techniques. Complexes molar conductance measurements displayed that all complexes (2–8) are non‐electrolyte. With general composition [M(H3L)(CH3COO)2H2O].nH2O, where M = Cd(II), Cu(II), Zn(II), Ni(II), Co(II) and Mn(II) while complex (8) has [VO(H3L)(SO4)H2O].2H2O formula. Based on analytical and spectral measurements, the octahedral or distorted octahedral geometries suggested for complexes. Ligand and complexes anti‐proliferative activities were assessed against three various human tumor cell lines including breast cancer (MCF‐7), liver cancer (HepG2) and lung cancer (A549) using SRB fluorometric assay and cis‐platin as positive control. The anti‐proliferative activity result indicated that the ligand and its complexes have considerable anti‐proliferative activity analogous to that of ordinarily utilized anti‐cancer drug (cis‐platin). They do their anti‐cancer activities by modifying free radical's generation via raising the superoxide dismutase activity and depletion of intracellular reduced glutathione level, catalase, glutathione peroxidase activities, escorted by highly generation of hydrogen peroxide, nitric oxide and other free radicals leading to tumor cells death, as monitoring by decreasing the protein and nucleic acids synthesis.  相似文献   

9.
Coordination Polymeric 1, 2‐Dithiooxalato and 1, 2‐Dithiosquarato Complexes. Syntheses and Structures of [BaCr2(bipy)2(1, 2‐dtox)4(H2O)2], [Ni(cyclam)(1, 2‐dtsq)]·2DMF, [Ni(cyclam)Mn(1, 2‐dtsq)2(H2O)2]·2H22, and [H3O][H5O2][Cu(cyclam)]3[Cu2(1, 2‐dtsq)3]2 1, 2‐Dithioxalate and 1, 2‐dithiosquarate ions have a pair of soft and hard donor centers and thus are suited for the formation of coordination polymeric complexes containing soft and hard metal ions. The structures of four compounds with building blocks containing these ligands are reported: In [BaCr2(bipy)2(1, 2‐dtox)4(H2O)2] Barium ions and pairs of Cr(bipy)(1, 2‐dtox)2 complexes form linear chains by the bisbidentate coordination of the dithiooxalate ligands towards Ba2+ and Cr3+. In [Ni(cyclam)(1, 2‐dtsq)]·2DMF short NÖH···O hydrogen bonds link the NiS2N4‐octahedra with C2v‐symmetry to an infinite chain. In [Ni(cyclam)Mn(1, 2‐dtsq)2(H2O)2]·2H2O the 1, 2‐dithiosquarato ligand shows a rare example of S‐coordination towards manganese(II). The sulfur atoms of cis‐MnO2S4‐polyedra are weakly coordinated towards the axial sites of square‐planar NiN4‐centers, thus forming a zig‐zag‐chain of Mn···Ni···Mn···Ni polyhedra. [H3O][H5O2][Cu (cyclam)]3[Cu2(1, 2‐dtsq)3]2 contains square planar [CuII(cyclam)]2+ ions and dinuclear [CuI2(1, 2‐dtsq)3]4— ions. Here each copper atom is trigonally planar coordinated by S‐donor atoms of the ligands. The Cu…Cu distance is 2.861(4)Å.  相似文献   

10.
张曙光  冯云龙 《中国化学》2009,27(5):877-881
四唑酸(–CN4H)与羧酸(–COOH)具有相似的酸性。对苯酚四唑硫酮(H2L)可以作为单齿(–S或–N)或双齿(–N, N或–N, S)配体与金属离子配位形成配位化合物。合成了4个以H2L为配体的金属(II)配合物:Co(HL)2(Py)2(H2O)2 (1), [Mn(HL)2(H2O)4]·2H2O (2), Mn(HL)2(Phen)2 (3), and [Zn(HL)2(Phen)2]·0.5H2O·1.5CH3OH (4),并用X−射线单晶衍射法测定了晶体结构。晶体结构分析表明,在这些配合物中所有的中心金属原子均呈现六配位的八面体构型。在配合物1和2中,HL–配体以氧原子与中心金属原子配位,而在配合物3和4中HL–配体则以硫原子与中心金属原子配位。  相似文献   

11.
Four metal‐organic coordination polymers [Co2(L)3(nipa)2]·6H2O ( 1 ), [Cd(L)(nipa)]·3H2O ( 2 ), [Co(L) (Hoxba)2] ( 3 ) and [Ni2(L)2(oxba)2(H2O)]·1.5L·3H2O ( 4 ) were synthesized by reactions of the corresponding metal(II) salts with the rigid ligand 1,4‐bis(1H‐imidazol‐4‐yl)benzene (L) and different derivatives of 5‐nitroisophthalic acid (H2nipa) and 4,4′‐oxybis(benzoic acid) (H2oxba), respectively. The structures of the complexes were characterized by elemental analysis, FT‐IR spectroscopy and single‐crystal X‐ray diffraction. Complexes 1 and 3 have the same one‐dimensional (1D) chain while 2 is a 6‐connected twofold interpenetrating three‐dimensional (3D) network with α ‐Po 412·63 topology based on the binuclear CdII subunits. Compound 4 features a puckered two‐dimensional (2D) (4,4) network, and the large voids of the packing 2D nets have accommodated the uncoordinated L guest molecules. An abundant of N–H···O, O–H···O and C–H···O hydrogen bonding interactions exist in complexes 1–4 , which contributes to stabilize the crystal structure and extend the low‐dimensional entities into high‐dimensional frameworks. Lastly, the photoluminiscent properties of compounds 2 were also investigated.  相似文献   

12.
A series of mononuclear metal complexes of Co(III), Ni(II) and Cu(II) with 2‐(2,4‐dichlorobenzamido)‐N′‐(3,5‐di‐tert‐butyl‐2‐hydroxybenzylidene)benzohydrazide ( LH 3 ) have been synthesized and characterized using various physico‐chemical, spectroscopic and single crystal X‐ray diffraction techniques. Structural studies of [Co( LH )( LH 2 )]·H2O ( 4 ) revealed the presence of both amido and imidol tautomeric forms of LH 3 , resulting in a distorted octahedral geometry around the Co(III) ion. [Ni( LH )(H2O)]·H2O ( 5 ) and [Cu( LH )(H2O)]·H2O ( 6 ) are isomorphous structures and crystallize in the monoclinic P21/c space group. The crystal structures of 4 , 5 and 6 are stabilized by hydrogen bonds formed by the enclathrated water molecules, C‐H···π and π···π interactions. Complexes along with the ligand ( LH 3 ) were screened for their in vivo anti‐inflammatory activity (carrageenan‐induced rat paw edema method) and in vitro antioxidant activity (DPPH free radical scavenging assay). Metal complexes have shown significant anti‐inflammatory and antioxidant potential.  相似文献   

13.
Reaction of 1‐phenyl‐4‐phenylacetyl‐2‐thiosemicarbazide (H2L) with diphenyllead(IV) dichloride and acetate afforded the complexes [PbPh2Cl2(H2L)2] and [PbPh2L]. The ligand and the complexes were characterized by elemental analyses, 1H and 13C NMR spectroscopy and X‐ray crystallography. In the asymmetric unit of crystals of the ligand there are four independent molecules of H2L and four molecules of water, which associate in the lattice as two independent sheets. The complex [PbPh2Cl2(H2L)2]·4MeOH has slightly distorted all‐trans octahedral geometry around the lead atom, and the fact that the ligand is S‐bound rather than O‐bound suggests that PbPh2Cl2 behaves as a “soft” Lewis acid. Hydrogen bonds involving NH groups, Cl atoms and MeOH molecules form a three‐dimensional supramolecular structure. In [PbPh2L]·Me2CO, the L2? anion bridges between two metal centres, binding to one strongly via the N and S atoms and weakly via the O atom, and to the other via the O atom, thus creating polymeric chains along the b axis. The double deprotonation and metallation of H2L induce significant changes in its configuration and lengthen the C‐S and C‐O bonds, suggesting an evolution of the dianion towards a thiol‐enol form.  相似文献   

14.
Three copper(II) complexes of the polydentate N‐donor ligand [4‐(4,6‐bis(1H‐pyrazol‐1‐yl)‐1,3,5‐triazin‐2‐yl)morpholine] (L) with chlorides, nitrates, and perchlorates as anions, namely, [CuCl2(L)] · 0.5(MeCN) ( 1 ), [Cu(NO3)2(H2O)(L)] · (MeCN) ( 2 ), and [Cu(L)2](ClO4)2 · (MeCN) ( 3 ) were synthesized and structurally characterized by IR, elemental analysis and X‐ray crystallographic analysis. In these complexes, the L ligand binds the copper(II) cation in the tridentate N3 form. The coordination arrangement around the central copper(II) atom is distorted square‐pyramidal in 1 but it is distorted octahedral in 2 and 3 . The interesting noncovalent interactions such as hydrogen bonds, π–π stacking, and anion–π interactions present in the solid‐state structures are discussed. The crystal results reveal that the counteranions play important roles in determining the diverse structures of these complexes. Moreover, the PXRD, TG, DRS, and fluorescence properties of compounds 1 – 3 were investigated.  相似文献   

15.
Hydrothermal reactions of tridentate rigid 2,4,6‐tris‐(benzimidazolyl‐2‐yl)pyridine (pytbzim) ligand and Zn(II)/Cd(II) salts generate binuclear complexes {[Cd2Cl2(pytbzim)2(H2O)2]·2NO3}n ( 1 ) and two isomorphs {[M2Cl2(pytbzim)2(H2O)2]Cl2·2H2O}n [M=Cd ( 2 ), Zn ( 3 )]. All complexes include [M2Cl2(pytbzim)2(H2O)2] dimers, which are further connected into a three‐dimensional supramolecular networks through ?‐? stacking interaction and hydrogen bonds. The solid state photoluminescent studies reveal good fluorescent properties of the pytbzim ligand and complexes 1 – 2 at room temperature.  相似文献   

16.
Metal Complexes with N2O2S2 Donor Set. Synthesis and Characterization of the Cobalt(II), Nickel(II), and Copper(II) Complexes of a 15‐ and a 16‐Membered Bis(2‐hydroxyethyl) Pendant Macrocyclic Ligand The macrocyclic ligands 6, 10‐bis(2‐hydroxyethyl)‐7, 8, 9, 11, 17, 18‐hexahydro‐dibenzo‐[e, n][1, 4, 8, 12]‐dithiadiaza‐cyclopentadecine ( 1 ) (L1) and 5, 13‐bis(2‐hydroxyethyl)‐7, 8, 9, 10, 16, 17, 18, 19, 20‐nonahydro‐dibenzo‐[g, o][1, 9, 5, 13]‐dithiadiaza‐cyclohexadecine (L4) have been prepared. They form the stable complexes [CoL1(‐H)CoL1](ClO4)3 ( 2 ), [NiL1](ClO4)2·MeOH ( 3 ), Λ‐[CuL1](ClO4)2·MeOH ( 4a ) and rac‐[CuL1](ClO4)2·MeOH ( 4b ), [NiL4](ClO4)2 ( 5 ), and [CuL4](ClO4)2 ( 6 ). The compounds 1 to 6 have been characterized by standard methods and single‐crystal X‐ray diffraction. In the complexes 2 to 6 the metal atoms are octahedrally coordinated by the N2O2S2 donor set of the ligands. L1 and L4 are folded herein along the N···M···S‐ and the N···M···N′‐axes, respectively. This results at the metal atom in a allcis‐configuration for the complexes of L1 and a trans‐N2cis‐O2cis‐S2‐configuration for the complexes of L4. The cobalt(II) complex 2 is a dimer, bridged by a rather short hydrogen bridge of 2.402(12)Å length. The copper(II) complexes of L1 and L4 differ with respect to the Jahn‐Teller‐distortion.  相似文献   

17.
The title complexes, hexaaquacobalt(II) bis(μ‐pyridine‐2,6‐dicarboxylato)bis[(pyridine‐2,6‐dicarboxylato)bismuthate(III)] dihydrate, [Co(H2O)6][Bi2(C7H4NO4)4]·2H2O, (I), and hexaaquanickel(II) bis(μ‐pyridine‐2,6‐dicarboxylato)bis[(pyridine‐2,6‐dicarboxylato)bismuthate(III)] dihydrate, [Ni(H2O)6][Bi2(C7H4NO4)4]·2H2O, (II), are isomorphous and crystallize in the triclinic space group P. The transition metal ions are located on the inversion centre and adopt slightly distorted MO6 (M = Co or Ni) octahedral geometries. Two [Bi(pydc)2] units (pydc is pyridine‐2,6‐dicarboxylate) are linked via bridging carboxylate groups into centrosymmetric [Bi2(pydc)4]2− dianions. The crystal packing reveals that the [M(H2O)6]2+ cations, [Bi2(pydc)4]2− anions and solvent water molecules form multiple hydrogen bonds to generate a supramolecular three‐dimensional network. The formation of secondary Bi...O bonds between adjacent [Bi2(pydc)4]2− dimers provides an additional supramolecular synthon that directs and facilitates the crystal packing of both (I) and (II).  相似文献   

18.
[MCl(H2L)(OH2)]·1.5H2O (M = Pd(II) ( 1 ) and Pt(II) ( 2 )) and [Ru(H2L)2(OH2)2]·3H2O ( 3 ) (H3L: N‐phenyl, N`‐(3‐triazolyl)thiourea) were synthesized, characterized and tested for their antibacterial activities against Staphylococcus aureus and Escherichia coli bacteria. The thiourea derivative is coordinated to Mn+ ions as a mono‐negatively N,S‐bidentate ligand via the enolization of C = S group and triazole N center. The density functional theory calculations reveal that presence of a water molecule in a trans position to triazole ring increased the stability of d8 metal ions complexes via the formation of strong Cl…NH intramolecular H‐bond. The cis‐Ru(II)‐isomer with two isoenergetically H2L? molecules are more stable than the trans‐analog. Coordination of H3L to Ru(II) ion did not alter the toxicity of the free ligand, while the interaction with the d8 metal ions gave rise to inactive compounds.  相似文献   

19.
The reactions of [Pt(dpma)(H2O)2]2+ (dpma = 2,2′‐dipyridylmethylamine) and [Pt(dpk)(H2O)2]2+ (dpk = 2,2′‐dipyridylketone) with the model nucleobases 1‐methylthymine (1‐MeT) and 1‐methyluracil (1‐MeU) were studied. Reaction products were characterized by 195Pt NMR spectroscopy and by X‐ray structure analysis. The symmetric dpma and dpk diaqua complexes form dinuclear complexes with 1‐methylthymine, acting as secondary bridging ligand via its N3 and O4 donor atoms. [Pt2(dpma)2(1‐MeT)2](ClO4)2 · H2O ( 5 ) and [Pt2(dpk)(dpk · H2O)(1‐MeT)2](PF6)2 · 4 H2O ( 6 ) both show a head‐to‐head arrangement. Biological tests show a significant in vitro antitumor activity of [Pt(dpk)Cl2] against the human glioma cell line U 87.  相似文献   

20.
Eight new two‐ligand complexes of copper(II) with 1,10‐phenanthroline and one of four different α‐hydroxy‐carboxylic acids (glycolic, lactic, mandelic and benzylic) were prepared. The complexes of general formula [Cu(HL)2(phen)] · nH2O (HL = monodeprotonated acid) ( 1 – 4 ) were characterized by elemental analysis, IR, electronic and EPR spectroscopy, magnetic measurements and thermo‐gravimetric analysis. The complexes of general formulae [Cu(HL)(phen)2](HL) · H2L · nSolv [ 1 a (HL = HGLYO, n = 1, Solv = MeCN) and 3 a (HL = HMANO, n = 0)] and [Cu(L)(phen)(OH2)] · nH2O [ 2 a (L = LACO2–, n = 4) and 4 a (L = BENO2–, n = 2)] were characterized by X‐ray diffractometry. In all these latter a pentacoordinated copper atom has a basically square pyramidal coordination polyhedron, the distortion of which towards a trigonal bipyramidal configuration has been evaluated in terms of the parameter τ. In 1 a and 3 a there are three forms of α‐hydroxycarboxylic acid: a monodentate monoanion, a monoanionic counterion, and a neutral molecule lying in the outer coordination sphere; in 2 a and 4 a the α‐hydroxycarboxylic acid is a bidentate dianion coordinating through carboxyl and hydroxyl oxygens.  相似文献   

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