- Toward a Porphyrin-Style NHC: A 16-Atom Ringed Dianionic Tetra-NHC Macrocycle and Its Fe(II) and Fe(III) Complexes
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N-heterocyclic carbenes (NHCs), and macrocyclic NHCs in particular, have been applied successfully to the stabilization of high oxidation states on transition metal complexes. This access to high oxidation states has enabled their application in oxidative catalysis including aziridination and epoxidation. However, the number of macrocyclic tetra-NHC ligands is still limited, especially those featuring anionic charge, which is beneficial in this regard. In this manuscript, we report a facile and high yielding synthesis for only the second example of such a dianionic, macrocyclic tetra-NHC ligand. This 16-atom macrocycle has the ring size and charge of a porphyrin but with the increased electron donation of NHCs. Its Fe(II) and Fe(III) complexes are reported, and their reactivities for ligand addition and oxidation were tested. Multiple oxidation catalysis reactions were tested with both the Fe(II) and Fe(III) complexes with reagents such as trimethylamine-N-oxide, oxygen (from air), diazodiphenylmethane, and P-tert-butyl-dibenzo-73phosphanorbornadiene (tBuPA) to explore the possibilities for single site oxidation reactions.
- Anneser, Markus R.,Elpitiya, Gaya R.,Powers, Xian B.,Jenkins, David M.
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p. 981 - 987
(2019/02/26)
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- Facile synthesis of dibenzo-7λ3-phosphanorbornadiene derivatives using magnesium anthracene
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Unprotected dibenzo-7λ3-phosphanorbornadiene derivatives RPA (A = C14H10 or anthracene; R = tBu, dbabh = NA, HMDS = (Me3Si)2N, iPr2N) are synthesized by treatment of the corresponding phosphorus dichloride RPCl 2 with MgA·3THF, in cold THF (~20% to 30% isolated yields). Anthracene and the corresponding cyclic phosphane (RP)n form as coproducts. Characteristic NMR features of the RPA derivatives include a doublet near 4 ppm in their 1H NMR spectra and a triplet peak in the 175-212 ppm region of the 31P NMR spectrum (2J PH ~14 Hz). The X-ray structures of the AN-PA and (HMDS)PA derivatives are discussed. Thermolysis of RPA benzene-d6 solutions leads to anthracene extrusion. This process has a unimolecular kinetic profile for the iPr2NPA derivative. The 7-phosphanorbornene anti-iPr2NP(C6H8) could be synthesized (70% isolated yield) by thermolysis of iPr2NPA in 1,3-cyclohexadiene.
- Velian, Alexandra,Cummins, Christopher C.
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supporting information
p. 13978 - 13981
(2012/10/29)
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- Ditelluride-promoted diphosphene transfer from a cyclotriphosphane to 2,3-dimethylbutadiene: characterization of di(aryltelluro)diphosphanes
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The cleavage of tri-tert-butylcyclotriphosphane 1 with di(4-methylphenyl)ditelluride 2 leads to 1,2-di-tert-butyl-1.2-di(4-methylphenyltelluro)diphosphane 3 and tetra-tert-butylcyclotetraphosphane.When 1 is heated with 2 in the presence of 2,3-dimethylbutadiene, the diphosphene trapping product 1,2-di-tert-butyl-4,5-dimethyl-1,2-diphosphacyclohex-4-ene 5 can be detected.The salt elimination reaction of tert-butyldichlorophosphane with 4-methylphenyltellurotelluromagnesium bromide leads mainly to 3 and ditelluride 2.Tellurophosphane 6 and 1,2-di-tert-butyl-1,2-di(aryltelluro)diphosphanes 3. 7 (7 : aryl = 2,4,6-triisopropylphenyl) are available in fair yields from di-tert-butylchlorophosphane or 1,2-di-tert-butyl-1,2-dichlorodiphosphane with metal tellurolates.At 90 deg C with 2,3-dimethylbutadiene, 7 acts as a source of 1,2-di-tert-butyldiphosphene trapped as cycloadduct 5. - Keywords: cyclophosphanes / phosphorus-carbon heterocycles / cleavage of phosphorus-phosphorus bonds / di(aryltelluro) diphosphanes / diphosphene transfer.
- Meyer, H. U.,Severengiz, T.,Mont, W. W. du
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p. 691 - 694
(2007/10/02)
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- Contributions to the Chemistry of Phosphorus, 173. - Synthesis and Properties of the Diphosphiranimines (tBuP)2C=NR (R = 2,4-tBu2C6H3, 2-tBuC6H4)
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The reaction of K(tBu)P-P(tBu)K with isocyanide dichlorides yields the first diphosphiranimines (tBuP)2C=NR.Besides, the cyclophosphanes (tBuP)n (n = 3,4) and the two configurational isomers of the corresponding 1,3-diphosphetane-2,4-diimines are formed.N
- Baudler, Marianne,Simon, Joachim
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p. 421 - 424
(2007/10/02)
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- Contributions in the Chemistry of Phosphorus, 131. Synthesis and Properties of the Methylenediphosphiranes (t-BuP)2C = CR2 (R = H, Me, 4-ClC6H4)
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The first methylenediphoshiranes (diphosphamethylenecyclopropanes) (t-BuP)2C = CH2 (1), (t-BuP)2C = CMe2 (2), and (t-BuP)2C = C(4-ClC6H4)2 (3) were synthesized by cyclocondensation of K(t-Bu)P - P(t-Bu)K with the corresponding 1,1-dichloroolefins.The homocyclophosphanes (t-BuP)n (n = 4,3) and in the case of 1 mainly H(t-Bu)P - P(t-Bu)H are formed as by-products.The three-membered heterocycles 2 and 3 could be purely isolated as surprisingly stable compounds.According to an X-ray single-crystal analysis 3 possesses approximately C2 symmetry and exhibits one of the smallest bonding angles φ (P - P - C) = 52.4 deg on a phosphorus atom experimentally proved so far.Along there are canals filled with disordered n-pentane molecules.
- Baudler, Marianne,Saykowski, Franz,Hintze, Michael,Tebbe, Karl-Friedrich,Heinlein, Thomas,et al.
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p. 1542 - 1550
(2007/10/02)
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