| 词条 | PMDTA |
| 释义 |
| Verifiedfields = changed | Watchedfields = changed | verifiedrevid = 430575274 | ImageFile = PMDTA.png | ImageFile_Ref = {{chemboximage|correct|??}} | ImageSize = 160 | ImageName = Skeletal formula of PMDTA | ImageFile1 = PMDTA-3D-balls.png | ImageFile1_Ref = {{chemboximage|correct|??}} | ImageName1 = Ball and stick model of PMDTA | ImageFile2 = PMDTA-3D-spacefill.png | ImageFile2_Ref = {{chemboximage|correct|??}} | ImageName2 = Spacefill model of PMDTA |Section1={{Chembox Identifiers | CASNo = 3030-47-5 | CASNo_Ref = {{cascite|correct|CAS}} | PubChem = 18196 | ChemSpiderID = 17187 | ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}} | EINECS = 221-201-1 | UNNumber = 2734 | ChEBI = 39475 | ChEBI_Ref = {{ebicite|changed|EBI}} | RTECS = IE2100000 | Beilstein = 1741396 | Gmelin = 27747 | SMILES = CN(C)CCN(C)CCN(C)C | StdInChI = 1S/C9H23N3/c1-10(2)6-8-12(5)9-7-11(3)4/h6-9H2,1-5H3 | StdInChI_Ref = {{stdinchicite|changed|chemspider}} | StdInChIKey = UKODFQOELJFMII-UHFFFAOYSA-N | StdInChIKey_Ref = {{stdinchicite|changed|chemspider}} }} |Section2={{Chembox Properties | C=9 | H=23 | N=3 | Appearance = Colorless liquid | Odor = Fishy, ammoniacal | Density = 830 mg mL−1 | MeltingPtC = -20 | BoilingPtC = 198 | VaporPressure = 31 Pa (at 20 °C) | RefractIndex = 1.442 }} |Section3={{Chembox Hazards | ExternalSDS = sigmaaldrich.com | GHSPictograms = {{gHS corrosion}} {{gHS skull and crossbones}} | GHSSignalWord = DANGER | HPhrases = {{h-phrases|302|311|314}} | PPhrases = {{p-phrases|280|305+351+338|310}} | FlashPtC = 53 | AutoignitionPtC = 155 | ExploLimits = 1.1–5.6% | LD50 = {{unbulleted list|232 mg kg−1 (dermal, rabbit)|1.351 g kg−1 (oral, rat)}} }} |Section4={{Chembox Related | OtherFunction_label = amines | OtherFunction = {{unbulleted list| triethylenetetramine|tmeda|diethylenetriamine|triazacyclononane}} | OtherCompounds = }} }} PMDTA (N,N,N′,N′′,N′′-pentamethyldiethylenetriamine) is an organic compound with the formula [(CH3)2NCH2CH2]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. SynthesisPMDTA is prepared from diethylenetriamine by the Eschweiler-Clarke reaction, involving the use of formaldehyde and formic acid.[1] [H2N(CH2)2]2NH + 5 CH2O + 5 HCO2H → [Me2NCH2CH2]2NMe + 5 CO2 + 5 H2O Comparison with diethylenetriamineUnlike 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.[2] Both ligands can coordinate metal complexes in arrangements where the three nitrogen centers are co-planar or mutually cis. Organolithium compounds and PMDTAPMDTA is used to modify the reactivity of organolithium compounds, which deaggregate in the presence of Lewis bases to enhance their reactivity.[3] Commonly, the ditertiary amine TMEDA is used in these applications; it binds to the lithium center as a bidentate ligand. PMDTA behaves analogously, but since it is tridentate, it binds more strongly to lithium. In contrast to TMEDA, PMDTA forms monomeric complexes with organolithium compounds. Both amines affect the regiochemistry of metalation.[3][4] In the PMDTA/n-BuLi adducts, the Li-C bonds are highly polarized, thus increasing the basicity of the butyl group.[5] The effect of PMDTA on lithium anilide is illustrative of PMDTA's complexing power. The complex, [{PhN(H)Li}3·2PMDTA], is trinuclear, featuring approximately colinear Li+ centers that are three-, four-, and five-coordinate. The central three-coordinate lithium atom is not bonded to PMDTA. One of the terminal Li centers is pseudo-tetrahedral in an N4 coordination sphere. The other terminal lithium atom is five-coordinate and binds to two anilino N centers and the PMDTA.[6] Transition metal and aluminium complexesPMDTA often forms five-coordinate complexes due to steric bulk of the methyl groups. PMDTA stabilize unusual cations. The first cationic derivative of alane, [H2Al(PMDTA)]+[AlH4]− was prepared by treating H3AlNMe3 with PMDTA.[5] References1. ^{{cite journal |author1=Marxer, A. |author2=Miescher, K. | title = Über die stufenweise Quaternisierung von aliphatischen Polyaminen. Neue Verbindungen mit ganglienblockierender Wirkung | journal = Helvetica Chimica Acta | year = 1951 | volume = 34 | issue = 3 | pages = 924–931 | doi = 10.1002/hlca.19510340327 }} 2. ^{{cite journal |author1=Angelici, R. J. |author2=Allison, J. W. | title = Stability Constants for Amino Acid Coordination by Substituted Diethylenetriamine Complexes of Copper(II) and the Kinetics of Amino Acid Ester Hydrolysis | journal = Inorganic Chemistry | year = 1971 | volume = 10 | issue = 10 | pages = 2238–2243 | doi = 10.1021/ic50104a030 }} 3. ^1 {{cite journal |author1=Strohmann, C. |author2=Gessner, V. H. | title = From the Alkyllitium Aggregate (nBuLi)2·PMDTA2 to Lithiated PMDTA | journal = Angewandte Chemie International Edition | year = 2007 | volume = 46 | issue = 24 | pages = 4566–4569 | doi = 10.1002/anie.200605105 }} 4. ^{{ cite encyclopedia | author = Fraenkel, G. | title = PMDTA | encyclopedia = Encyclopedia of Reagents for Organic Synthesis | pages = 806–813 | year = 2002 | publisher = Wiley-VCH | location = Weinheim | doi = 10.1002/047084289X.rp028 | isbn = 0-471-93623-5 }} 5. ^1 {{cite book | author = Elschenbroich, C. | year = 2006 | publisher = Wiley-VCH | location = Weinheim | title = Organometallics | pages = 45–46 | isbn = 978-3-527-29390-2 }} 6. ^{{cite journal |author1=Barr, D. |author2=Clegg, W. |author3=Cowton, L. |author4=Horsburgh, L. |author5=Mackenzie, F. M. |author6=Mulvey, R. | title = Lithium Anilide Complexed by pmdeta: Expectations of a simple monomer, but in Reality an Odd Trinuclear Composition Combining Three-, Four-, and Five-coordinate Lithium | journal = Journal of the Chemical Society, Chemical Communications | year = 1995 | volume = 1995 | issue = 8 | pages = 891–892 | doi = 10.1039/C39950000891 }} 2 : Polyamines|Tridentate ligands |
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