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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'' com ... [...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 mem ... [...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 Formic acid (), systematically named methanoic acid, is the simplest carboxylic acid, and has the chemical formula HCOOH and structure . It is an important intermediate in chemical synthesis and occurs naturally, most notably in some ants. Es .... :(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 ch ... [...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 and homogeneous catalysis. Because the ligands are polydentate, they do not readily dissociate from the metal centre. Many tripodal ligands have C3 symmetry. Coordination chemistry In their coordination complexes with an octahedral molecular geometry the tridentate tripod ligands occupy one face, leading to a fixed 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 metal centres, these ligands impose C3 symmetry, which can lead to uncommon ligand field splitting patterns. Tripodal ligands are often able to coordinately saturate metal ions with lower coordination numbers. One tripodal ligand of commercial significance is nitrilotriacetate, N(CH2CO2−)3 because it is cheaply produced and has a high affinity f ... [...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 The Curtius rearrangement (or Curtius reaction or Curtius degradation), first defined by Theodor Curtius in 1885, is the thermal decomposition of an acyl azide to an isocyanate with loss of nitrogen gas. The isocyanate then undergoes attack by a va ... starting from cyclohexanetricarboxylic acid. Related ligands * Tris(aminomethyl)ethane, 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] |
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 The Curtius rearrangement (or Curtius reaction or Curtius degradation), first defined by Theodor Curtius in 1885, is the thermal decomposition of an acyl azide to an isocyanate with loss of nitrogen gas. The isocyanate then undergoes attack by a va ... starting from cyclohexanetricarboxylic acid. Related ligands * Tris(aminomethyl)ethane, 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] |
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 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 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 HSAB theory, hard, such as copper(II) and iron(II). Most of its complexes have the formula [M(9-ane-S3)2]2+ and are octahedral geometry, octahedral. The point group of [M(9-ane-S3)2]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 [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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