1,5-Diaza-3,7-diphosphacyclooctanes: Difference between revisions
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[[File:P2N2ligand.png|thumb|180 px|P2N2 ligand structure |
[[File:P2N2ligand.png|thumb|180 px|P2N2 ligand structure]] |
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'''1,5-Diaza-3,7-diphosphacyclooctanes''' are [[organophosphorus compound]]s with the formula [R'NCH |
'''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. |
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|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> |
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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> |
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==Synthesis and reactions== |
==Synthesis and reactions== |
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The ligands are prepared by the condensation of a primary phosphine, [[formaldehyde]], and a primary amine: |
The ligands are prepared by the condensation of a primary phosphine, [[formaldehyde]], and a primary amine:<ref>{{cite journal |doi=10.15227/orgsyn.101.0001 |title=Synthesis of Secondary Benzylic Alcohols by Reductive Arylation of Aldehydes: α-Phenyl-6-quinolinemethanol |date=2024 |last1=t. Thomas |first1=Gilian |first2=Eric S.|last2=Isbrandt|first3=Stephen G.|last3=Newman|journal=Organic Syntheses |volume=101 |pages=1–20 }}</ref> |
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:{{chem2|2 RPH2 + 4 CH2O + 2 RNH2 → [RNCH2P(R')CH2]2 + 4 H2O}} |
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2 RPH<sub>2</sub> + 4 CH<sub>2</sub>O + 2 RNH<sub>2</sub> → [RNCH<sub>2</sub>P(R')CH<sub>2</sub>]<sub>2</sub> + 4 H<sub>2</sub>O |
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Diazadiphosphacyclooctanes function as chelating |
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+}}. |
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Cationic complexes of these |
Cationic complexes of these {{chem2|P2N2}} and related ligands often exhibit enhanced reactivity toward H<sub>2</sub>. These complexes serve as electrocatalysts for H<sub>2</sub> evolution. |
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[[File:MP2N2M&P2NM.png|thumb| |
[[File:MP2N2M&P2NM.png|thumb|155px|Conformation of chelate rings in P2N2-M and P2N-M complexes]] |
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==Related ligands== |
==Related ligands== |
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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| |
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'. |
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==References== |
==References== |
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{{Reflist}} |
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<references /> |
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{{DEFAULTSORT:Diaza-3, 7-diphosphacyclooctanes, 1, 5-}} |
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[[Category:Chelating agents]] |
[[Category:Chelating agents]] |
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[[Category: |
[[Category:Diphosphines]] |
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[[Category:Phosphorus heterocycles]] |
[[Category:Phosphorus heterocycles]] |
Latest revision as of 04:25, 29 January 2024
![](http://upload.wikimedia.org/wikipedia/commons/thumb/9/9a/P2N2ligand.png/180px-P2N2ligand.png)
1,5-Diaza-3,7-diphosphacyclooctanes are organophosphorus compounds with the formula [R'NCH2P(R)CH2]2, often abbreviated PR2NR'2. They are air-sensitive white solids that are soluble in organic solvents. The ligands exist as meso and d,l-diastereomers, but only the meso forms function as bidentate ligands.[1][2]
Some metal-PR2NR'2 complexes catalyze the hydrogen evolution reaction as well as the oxidation of hydrogen (H2). The catalytic mechanism involves the interaction of substrate with the amines in the second coordination sphere.[3][4]
Synthesis and reactions
[edit]The ligands are prepared by the condensation of a primary phosphine, formaldehyde, and a primary amine:[5]
- 2 RPH2 + 4 CH2O + 2 RNH2 → [RNCH2P(R')CH2]2 + 4 H2O
Diazadiphosphacyclooctanes function as chelating diphosphine ligands. Typical nickel complexes contain two such ligands are give the formula [Ni(PR2NR'2)2]2+.
Cationic complexes of these P2N2 and related ligands often exhibit enhanced reactivity toward H2. These complexes serve as electrocatalysts for H2 evolution.
![](http://upload.wikimedia.org/wikipedia/commons/thumb/a/ad/MP2N2M%26P2NM.png/155px-MP2N2M%26P2NM.png)
Related ligands
[edit]Azadiphosphacycloheptanes are a related family of diphosphines, but containing only one amine. They are prepared by condensation of 1,2-bis(phenylphosphino)ethane, formaldehyde, and a primary amine.[6] From the meso-isomer, typical nickel complexes contain two such ligands, i.e. [Ni(PR2NR')2]2+. When bound to metals, these ligands adopt a conformation similar to that of 1,4-diazacycloheptanes. Acyclic phosphine-amine ligands have the formula (R2PCH2)NR'.
References
[edit]- ^ Erika Bálint; Adám Tajti; Anna Tripolszky; György Keglevich (2018). "Synthesis of platinum, palladium and rhodium complexes of α-aminophosphine ligands". Dalton Trans. 47 (14): 4755–4778. doi:10.1039/C8DT00178B. PMID 29565437.
- ^ Wiedner, Eric S.; Appel, Aaron M.; Raugei, Simone; Shaw, Wendy J.; Bullock, R. Morris (2022). "Molecular Catalysts with Diphosphine Ligands Containing Pendant Amines". Chemical Reviews. 122 (14): 12427–12474. doi:10.1021/acs.chemrev.1c01001. PMID 35640056. S2CID 249237539.
- ^ Yang, J. Y.; Chen, S.; Dougherty, W. G.; Kassel, W. S.; Bullock, R. M.; DuBois, D. L.; Raugei, S.; Rousseau, R.; Dupuis, M.; Rakowski DuBois, M. (2010). "Hydrogen oxidation catalysis by a nickel diphosphine complex with pendant tert-butyl amines". Chem. Commun. 46 (45): 8618–8620. doi:10.1039/c0cc03246h. PMID 20938535. S2CID 34168725.
- ^ Bullock, R. M.; Helm, M. L. (2015). "Molecular Electrocatalysts for Oxidation of Hydrogen Using Earth-Abundant Metals: Shoving Protons Around with Proton Relays". Acc. Chem. Res. 48 (7): 2017–2026. doi:10.1021/acs.accounts.5b00069. OSTI 1582563. PMID 26079983.
- ^ t. Thomas, Gilian; Isbrandt, Eric S.; Newman, Stephen G. (2024). "Synthesis of Secondary Benzylic Alcohols by Reductive Arylation of Aldehydes: α-Phenyl-6-quinolinemethanol". Organic Syntheses. 101: 1–20. doi:10.15227/orgsyn.101.0001.
- ^ Karasik, A. A.; Balueva, A. S.; Moussina, E. I.; Naumov, R. N.; Dobrynin, A. B.; Krivolapov, D. B.; Litvinov, I. A.; Sinyashin, O. G. (2008). "1,3,6-azadiphosphacycloheptanes: a novel type of heterocyclic diphosphines". Heteroatom Chemistry. 19 (2): 125–132. doi:10.1002/hc.20397.