Просмотр кода страницы Английская Википедия:1,5-Diaza-3,7-diphosphacyclooctanes

{{Английская Википедия/Панель перехода}}
[[File:P2N2ligand.png|thumb|180 px|P2N2 ligand structure]]
'''1,5-Diaza-3,7-diphosphacyclooctanes''' are [[organophosphorus compound]]s with the formula [R'NCH{{sub|2}}P(R)CH{{sub|2}}]{{sub|2}}, often abbreviated P{{sup|R}}{{sub|2}}N{{sup|R'}}{{sub|2}}.  They are air-sensitive white solids that are soluble in organic solvents.  The ligands exist as meso and d,l-[[diastereomer]]s, but only the meso forms function as [[bidentate ligand]]s.<ref>{{cite journal|title=Synthesis of platinum, palladium and rhodium complexes of α-aminophosphine ligands|author1=Erika Bálint |author2=Adám Tajti |author3=Anna Tripolszky |author4=György Keglevich|year=2018|journal=Dalton Trans.
|volume=47|issue=14|pages=4755–4778|doi=10.1039/C8DT00178B|pmid=29565437|doi-access=free}}</ref><ref>{{cite journal |doi=10.1021/acs.chemrev.1c01001|title=Molecular Catalysts with Diphosphine Ligands Containing Pendant Amines |year=2022 |last1=Wiedner |first1=Eric S. |last2=Appel |first2=Aaron M. |last3=Raugei |first3=Simone |last4=Shaw |first4=Wendy J. |last5=Bullock |first5=R. Morris |journal=Chemical Reviews |volume=122 |issue=14 |pages=12427–12474 |pmid=35640056 |s2cid=249237539}}</ref>

Some metal-P{{sup|R}}{{sub|2}}N{{sup|R'}}{{sub|2}} [[Chelate complex|complexes]] catalyze the [[hydrogen evolution reaction]] as well as the oxidation of [[hydrogen]] (H{{sub|2}}).  The catalytic mechanism involves the interaction of substrate with the amines in the [[second coordination sphere]].<ref>{{cite journal|last1=Yang|first1=J. Y.|last2=Chen|first2=S.|last3=Dougherty|first3=W. G.|last4=Kassel|first4=W. S.|last5=Bullock|first5=R. M.|last6=DuBois|first6=D. L.|last7=Raugei|first7=S.|last8=Rousseau|first8=R.|last9=Dupuis|first9=M.|last10=Rakowski DuBois|first10=M.|s2cid=34168725|title=Hydrogen oxidation catalysis by a nickel diphosphine complex with pendant tert-butyl amines|journal=Chem. Commun.|volume=46|issue=45|year=2010|pages=8618–8620|doi=10.1039/c0cc03246h|pmid=20938535}}</ref><ref>{{cite journal|last1=Bullock|first1=R. M.|last2=Helm|first2=M. L.|title=Molecular Electrocatalysts for Oxidation of Hydrogen Using Earth-Abundant Metals: Shoving Protons Around with Proton Relays|journal=Acc. Chem. Res.|year=2015|volume=48|issue=7|pages=2017–2026|doi = 10.1021/acs.accounts.5b00069|pmid=26079983|osti=1582563}}</ref>

==Synthesis and reactions==
The ligands are prepared by the condensation of a primary phosphine, [[formaldehyde]], and a primary amine:
:2 RPH{{sub|2}} + 4 CH{{sub|2}}O + 2 RNH{{sub|2}} → [RNCH{{sub|2}}P(R')CH{{sub|2}}]{{sub|2}} + 4 H{{sub|2}}O

Diazadiphosphacyclooctanes function as chelating [[diphosphine]] ligands. Typical nickel complexes contain two such ligands are give the formula [Ni(P{{sup|R}}{{sub|2}}N{{sup|R'}}{{sub|2}}){{sub|2}}]{{sup|2+}}.

Cationic complexes of these P{{sub|2}}N{{sub|2}} and related ligands often exhibit enhanced reactivity toward H{{sub|2}}. These complexes serve as electrocatalysts for H{{sub|2}} production.
[[File:MP2N2M&P2NM.png|thumb|155px|Conformation of chelate rings in P2N2-M and P2N-M complexes]]

==Related ligands==
Azadiphosphacycloheptanes are a related family of [[diphosphine]]s, but containing only one amine.  They are prepared by condensation of 1,2-bis(phenylphosphino)ethane, formaldehyde, and a primary amine.<ref>{{cite journal|last1=Karasik|first1=A. A.|last2=Balueva|first2=A. S.|last3=Moussina|first3=E. I.|last4=Naumov|first4=R. N.|last5=Dobrynin|first5=A. B.|last6=Krivolapov|first6=D. B.|last7=Litvinov|first7=I. A.|last8=Sinyashin|first8=O. G.|title=1,3,6-azadiphosphacycloheptanes: a novel type of heterocyclic diphosphines|journal=Heteroatom Chemistry|year=2008|volume=19|issue=2|pages=125–132|doi=10.1002/hc.20397}}</ref> From the meso-isomer, typical nickel complexes contain two such ligands, i.e. [Ni(P{{sup|R}}{{sub|2}}NR'){{sub|2}}]{{sup|2+}}.  When bound to metals, these ligands adopt a conformation similar to that of [[1,4-Diazacycloheptane|1,4-diazacycloheptane]]s.  Acyclic phosphine-amine ligands have the formula (R{{sub|2}}PCH{{sub|2}})NR'.

==References==
{{Reflist}}

{{DEFAULTSORT:Diaza-3, 7-diphosphacyclooctanes, 1, 5-}}
[[Category:Chelating agents]]
[[Category:Diphosphines]]
[[Category:Phosphorus heterocycles]]
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