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Tridentate Ligand
A tridentate ligand (or terdentate ligand) is a ligand that has three atoms that can function as acceptor atoms in a coordination complex. Well-known tridentate ligands include diethylenetriamine with three nitrogen donor atoms, and the iminodiacetate anion which consists of one deprotonated amine nitrogen and a pair of carboxylate groups. An octahedrally coordinated atom has six positions around it. Two tridentate ligands may form a complex with such an atom. There are two possible arrangements for such a complex: ''fac'' where the coordination is in a triangle on one face of the octahedron, and ''mer'' where the coordinating atoms are in an arc around the central atom, with two atoms of the ligand opposite each other. ''Fac'' tridentate ligands are termed scorpionate ligands, especially in reference to polypyrazolylborates. If the tridentate ligand is not symmetrical, then in the ''fac'' complexes in octahedral coordination there are three possible isomers. In the ''mer'' c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mida
{{disambiguation, geo ...
Mida may refer to: *Mida, Lorestan, a village in Iran *Mida (website), Israeli online magazine *Lucia Mida, a golfer * MIDA * MIDA, (Brand), Motorcycle Helmet and Accessories Brand, British Design. *''Mida'', a genus of Santalaceae The Santalaceae, sandalwoods, are a widely distributed family of flowering plants (including small trees, shrubs, perennial herbs, and epiphytic climbersHewson & George t al.br>''Santalaceae'' taxonomy, 1984, pp. 191-194.) which, like other memb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PMDTA
PMDTA (''N'',''N'',''N′'',''N′′'',''N′′''-pentamethyldiethylenetriamine) is an organic compound with the formula CH3)2NCH2CH2sub>2NCH3. PMDTA is a basic, bulky, and flexible, tridentate ligand that is a used in organolithium chemistry. It is a colorless liquid, although impure samples appear yellowish. Synthesis PMDTA is prepared from diethylenetriamine by the Eschweiler-Clarke reaction, involving the use of formaldehyde and formic acid. :(H2N H2sub>2)2NH + 5 CH2O + 5 HCO2H → (Me2N H2sub>2)2NMe + 5 CO2 + 5 H2O Comparison with diethylenetriamine Unlike diethylenetriamine, all three amines in PMDTA are tertiary. Both PMDTA and diethylenetriamine are tridentate ligands that form two five-membered chelate rings. The σ-donating properties of the amino groups of diethylenetriamine are greater than that of PMDTA in copper(II) complexes. Both ligands can coordinate metal complexes in arrangements where the three nitrogen centers are co-planar or mutuall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tripodal Ligand
Tripodal ligands are tri- and tetradentate ligands. They are popular in research in the areas of coordination chemistry A coordination complex consists of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of chemical bond, bound molecules or ions, that are in turn known as ''ligands'' or complexing ... and homogeneous catalysis. Because the ligands are polydentate, they do not readily dissociate from the metal centre. Many tripodal ligands have C3 symmetry group, symmetry. Coordination chemistry In their coordination complexes with an octahedral molecular geometry the tridentate tripod ligands occupy one face, leading to a fixed Coordination complexes#Cis–trans isomerism and facial–meridional isomerism, facial (or ''fac'') geometry. The tetradentate tripodal ligands occupy four contiguous sites, leaving two ''cis'' positions available on the octahedral metal center. When bound to four- and five-coordinate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cis,cis-1,3,5-triaminocyclohexane
''cis'',''cis''-1,3,5-Triaminocyclohexane is an organic compound with the formula (CH2CHNH2)3. It is a triamine. Of the many isomers possible for triaminocyclohexane, the ''cis'',''cis''-1,3,5-derivative has attracted attention because it is a common tripodal ligand, abbreviated as tach. It is a colorless oil. It is a popular tridentate ligand in coordination chemistry. It is prepared from the triscarbamate of cyclohexane. The latter is generated via the Curtius rearrangement starting from cyclohexanetricarboxylic acid. Related ligands *Tris(aminomethyl)ethane 1,1,1-Tris(aminomethyl)ethane (TAME) is an organic compound with the formula CHC(CHNH). It is a colorless liquid. It is classified as a polyamine tripodal ligand, i.e., capable of binding to metal ions through three sites and hence is a tridentate ..., another tripodal triamine (CH3C(CH2NH2]3) References {{DEFAULTSORT:Triaminocyclohexane, cis,cis-1,3,5- Tripodal ligands Polyamines ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1,4,7-triazacyclononane
1,4,7-Triazacyclononane, known as "TACN" which is pronounced "tack-en," is an aza-crown ether with the formula (C2H4NH)3. TACN is derived, formally speaking, from cyclononane by replacing three equidistant CH2 groups with NH groups. TACN is one of the oligomers derived from aziridine, C2H4NH. Other members of the series include piperazine, C4H8(NH)2, and the cyclic tetramer 1,4,7,10-tetraazacyclododecane. Synthesis The ligand is prepared from diethylene triamine as follows by macrocyclization using ethyleneglycol ditosylate. :H2NCH2CH2NHCH2CH2NH2 + 3 TsCl → Ts(H)NCH2CH2N(Ts)CH2CHH2N(H)Ts + 3 HCl :Ts(H)NCH2CH2N(Ts)CH2CH2N(H)Ts + 2 NaOEt → Ts(Na)NCH2CH2N(Ts)CH2CH2N(Na)Ts :Ts(Na)NCHH2CH2N(Ts)CH2CH2N(Na)Ts + TsOCH2CH2OTs + → CH2CH2N(Ts)sub>3 + 2 NaOTs : CH2CH2N(Ts)sub>3 + 3 H2O → H2CH2NHsub>3 + 3 HOTs Coordination chemistry TACN is a popular tridentate ligand. It is threefold symmetric and binds to one face of an octahedron of metalloids and transition ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Me3TACN
1,4,7-Trimethyl-1,4,7-triazacyclononane is the aza-crown ether with the formula (CH2CH2NCH3)3. This colorless liquid is the N-methylated derivative of triazacyclononane (TACN), a face-capping tridentate ligand that is popular in coordination chemistry A coordination complex consists of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of bound molecules or ions, that are in turn known as ''ligands'' or complexing agents. Many .... Although TACN is known for forming 2:1 "sandwich" complexes with many metal ions, corresponding 2:1 complexes of Me3TACN are only known for Ag+, Na+, and K+. This effect is mainly due to the greater bulk of Me3TACN, which requires ions with a larger ionic radius to accommodate two ligands. Several related derivatives have been prepared with diverse substituents on nitrogen. References {{DEFAULTSORT:Trimethyl-1,4,7-triazacyclononane, 1,4,7- Polyamines Chelating agents M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1,4,7-Trimethyl-1,4,7-triazacyclononane
1,4,7-Trimethyl-1,4,7-triazacyclononane is the aza-crown ether with the formula (CH2CH2NCH3)3. This colorless liquid is the N-methylated derivative of triazacyclononane (TACN), a face-capping tridentate ligand that is popular in coordination chemistry A coordination complex consists of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of chemical bond, bound molecules or ions, that are in turn known as ''ligands'' or complexing .... Although TACN is known for forming 2:1 "sandwich" complexes with many metal ions, corresponding 2:1 complexes of Me3TACN are only known for Ag+, Na+, and K+. This effect is mainly due to the greater bulk of Me3TACN, which requires ions with a larger ionic radius to accommodate two ligands. Several related derivatives have been prepared with diverse substituents on nitrogen. References {{DEFAULTSORT:Trimethyl-1,4,7-triazacyclononane, 1,4,7- Polyamines Chelating agents Mac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1,4,7-Trithiacyclononane
1,4,7-Trithiacyclononane, also called 9-ane-S3, is the thia-crown ether with the formula (CH2CH2S)3. This cyclic thioether is most often encountered as a tridentate ligand in coordination chemistry, where it forms transition metal thioether complexes. 9-ane-S3 forms complexes with many metal ions, including those considered hard Hard may refer to: * Hardness, resistance of physical materials to deformation or fracture * Hard water, water with high mineral content Arts and entertainment * ''Hard'' (TV series), a French TV series * Hard (band), a Hungarian hard rock super ..., such as copper(II) and iron(II). Most of its complexes have the formula (9-ane-S3)2sup>2+ and are octahedral. The point group of (9-ane-S3)2sup>2+ is S6. Synthesis This compound was first reported in 1977, and the current synthesis entails the assembly within the coordination sphere of a metal ion followed by decomplexation: : References {{DEFAULTSORT:Trithiacyclononane, 1,4,7- Chelating age ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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