Some special aspects of the stereochemistry of coordination compounds

(Fig. la). In contrast, functional groups such as nitriles take on a linear arrangement at nitrogen and necessitate a larger scaffold and more convergent C shape to achieve the same geometries (Fig. lb). Accordingly, multidentate nitriles are commonly oligomeric and polymeric structures and have been successfully used to assemble expansive threedimensional arrays (8,9). Chelating di-and trinitriles are also known, but they invariably bind to the same face of the metal and not to opposing faces (10)(11)(12)(13) MATERIALS AND METHODSThe C-Shaped and S-Shaped Isomers of Bisamide 3. (See Fig. 2.) A 1-to-1 mixture of C-and S-shaped isomers of diacid 2 (1.16 g, 1.17 mmol), thionyl chloride (5 ml), and four drops of N,N-dimethylformamide (DMF) were heated at reflux for 2.5 h (14). The reaction mixture was evaporated to a yellow solid under reduced pressure. The crude product was dissolved in 50 ml of CH2Cl2 and treated with 10 ml of concentrated aqueous ammonium hydroxide. The mixture was stirred vigorously for 1 h and then washed with 1.0 M HCI (twice with 100 ml), then dried over MgSO4. Chromatography on silica gel (MeOH/CH2Cl2, 0.75%) gave the lower-Rf, S-shaped isomer of 3 (400 mg, 35%) and the higher-Rf, C-shaped isomer of 3 (462 mg, 41%

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“…Bidentate ligands that bind in a trans or rectilinear fashion are very rare (1,2). The difficulties can be seen in Fig.…”

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confidence: 99%

A rigid trans-spanning dinitrile ligand.

Shimizu

Rebek

1996

Proc. Natl. Acad. Sci. U.S.A.

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“…Generally, only one pair of enantiomers, which were resolved, was observed, indicating a stereoselectivity introduced by the different ligating atoms. [16] All possible diastereoisomers of our complexes with linear hexadentate ligands are shown in Scheme 2. When dealing with this kind of octahedral compound, the α (or β)-cis or cis-trans-cis types of nomenclature are not adequate to describe the geometry of the complex, as they do not differentiate between the wrapping of the ligand around the metal ion in all the isomers; for example, the two configurations I and III (Scheme 2) are both cis-trans-cis.…”

Section: Configuration Of the Octahedral Complexesmentioning

confidence: 99%

Configuration of Octahedral Metal Compounds − Equilibrium, Crystal and Molecular Structure of Nickel(II) Complexes of Linear N₂O₄, N₄S₂ or N₆ Donors Set Atoms Ligands

et al. 2004

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“…These have several applications in organic studies, such as for building new heterocyclic systems, for identification, detection, and determination of aldehydes and ketones, for purification of carbonyl or amino compounds, or for the protection of these groups during the complex formation or such sensitive reactions [1]. They have other side applications in various other fields, coordination chemistry [2][3][4][5][6][7][8][9], analytical chemistry [10][11][12][13][14][15][16], pigments and dyes [17], and polymer industries [18], in vitamins and enzymes [4] for model biomolecules. There is a special mention of these complexes in agriculture [4] as fungicides, pesticides, and bacteriocides.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Complexes Synthesized Using Schiff Base Ligands and Their Screening for Toxicity Two Fungal and One Bacterial Species on Rice Pathogens

Mangamamba¹,

Ganorkar²,

Swarnabala

2014

International Journal of Inorganic Chemistry

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Coordination complexes with metal ions Cu(II), Ni(II), Co(II), Fe(III), Mn(II), Cr(III), and VO(II) with six ligands formed by condensation products using azides and aldehydes or ketones are characterized. Both the ligands and the complexes synthesized are characterized by C, H, N, Cl and metal analyses, IR, UV-Vis, TGA, and magnetic susceptibility for tentative structure proposal. Several of them are screened for their toxicity (i.e., physiological activity) against fungal species Rhizoctonia solani and Acrocylindrium oryzae and a bacterium, Xanthomonas oryzae on rice pathogens. The study shows that the observed physiological activity is enhanced for the metal complexes as compared to the simple metal salts or ligands, except in the case of L3 or HAEP ligand, where the free -OH and -NH 2 groups on the ligand seemed to have inhibited the activity. It is also observed that the order of activity has a dependence on the increased atomic weight of the metal ion in use. In some cases, especially the VO(II) complexes, they are found to be better than the standards in use, both for the fungicides and for the bactericide.

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Some special aspects of the stereochemistry of coordination compounds

Cited by 19 publications

References 146 publications

A rigid trans-spanning dinitrile ligand.

A rigid trans-spanning dinitrile ligand.

Configuration of Octahedral Metal Compounds − Equilibrium, Crystal and Molecular Structure of Nickel(II) Complexes of Linear N₂O₄, N₄S₂ or N₆ Donors Set Atoms Ligands

Characterization of Complexes Synthesized Using Schiff Base Ligands and Their Screening for Toxicity Two Fungal and One Bacterial Species on Rice Pathogens

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Some special aspects of the stereochemistry of coordination compounds

Cited by 19 publications

References 146 publications

A rigid trans-spanning dinitrile ligand.

A rigid trans-spanning dinitrile ligand.

Configuration of Octahedral Metal Compounds − Equilibrium, Crystal and Molecular Structure of Nickel(II) Complexes of Linear N2O4, N4S2 or N6 Donors Set Atoms Ligands

Characterization of Complexes Synthesized Using Schiff Base Ligands and Their Screening for Toxicity Two Fungal and One Bacterial Species on Rice Pathogens

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Configuration of Octahedral Metal Compounds − Equilibrium, Crystal and Molecular Structure of Nickel(II) Complexes of Linear N₂O₄, N₄S₂ or N₆ Donors Set Atoms Ligands