Theory and Computation in the Study of Nitrenes and their Excited‐State Photoprecursors

Vyas, Shubham; Winter, Arthur H.; Hadad, Christopher M.

doi:10.1002/9781118560907.ch2

Cited by 5 publications

(6 citation statements)

References 152 publications

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“…23–25 Upon light or thermal activation, the azido group in the PFPA structure is converted to a highly reactive nitrene species that readily inserts into CH and NH bonds or undergoes cycloaddition reaction with C=C bonds. 23,26,27 This bimolecular reaction, which is much less efficient in alkyl azides or phenyl azides, 28–31 makes PFPAs highly efficient in surface functionalization. The functionalization process is simple and reproducible, and has been proven to be efficient for the immobilization of graphene, proteins and other small biomolecules, carbohydrates and synthetic polymers onto surfaces.…”

Section: Introductionmentioning

confidence: 99%

“…The surface structure and composition of materials determine their properties and performance; therefore, tailoring the surface properties of a material through surface modification is an important method to control the function of materials. − Self-assembled monolayers (SAMs) have become an excellent technique for the modification and functionalization of a variety of surfaces. ,,− Azide-terminated SAMs provide an excellent route for thin film fabrication and allow tailoring surface properties through covalent immobilization. − The most common uses of azides are click chemistry − and photochemistry. , Recently, perfluorophenylazides (PFPAs) have been developed to introduce functional groups onto solid surfaces. − Upon light or thermal activation, the azido group in the PFPA structure is converted to a highly reactive nitrene species that readily inserts into CH and NH bonds or undergoes cycloaddition reaction with CC bonds. ,, This bimolecular reaction, which is much less efficient in alkyl azides or phenyl azides, − makes PFPAs highly efficient in surface functionalization. The functionalization process is simple and reproducible and has been proven to be efficient for the immobilization of graphene, proteins and other small biomolecules, carbohydrates, and synthetic polymers onto surfaces. ,− Moreover, the surface density of immobilized molecules can be controlled through the PFPA concentration. , The PFPA chemistry has been used to globally modify surfaces or to modify discrete areas by arraying techniques such as photomasking or printing devices …”

Section: Introductionmentioning

confidence: 99%

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X-ray Photoelectron Spectroscopy Investigation of the Nitrogen Species in Photoactive Perfluorophenylazide-Modified Surfaces

et al. 2013

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X-ray Photoelectron Spectroscopy (XPS) was used to characterize the nitrogen species in perfluorophenylazide (PFPA) self-assembled monolayers. PFPA chemistry is a novel immobilization method for tailoring the surface properties of materials. It is a simple route for the efficient immobilization of graphene, proteins, carbohydrates and synthetic polymers onto a variety of surfaces. Upon light irradiation, the azido group in PFPA is converted to a highly reactive singlet nitrene species that readily undergoes CH insertion and C=C addition reactions. Here, the challenge of characterizing the PFPA modified surfaces was addressed by detailed XPS experimental analyses. The three nitrogen peaks detected in the XPS N1s spectra were assigned to amine/amide (400.5 eV) and azide (402.1 and 405.6 eV) species. The observed 2:1 ratio of the areas from the 402.1 eV to 405.6 eV peaks suggests the assignment of the peak at 402.1 eV to the two outer nitrogen atoms in the azido group and assignment of the peak at 405.6 eV to the central nitrogen atom in the azido group. The azide decomposition as the function of x-ray exposure was also determined. Finally, XPS analyses were conducted on patterned graphene to investigate the covalent bond formation between the PFPA and graphene. This study provides strong evidence for the formation of covalent bonds during the PFPA photocoupling process.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

X-ray Photoelectron Spectroscopy Investigation of the Nitrogen Species in Photoactive Perfluorophenylazide-Modified Surfaces

et al. 2013

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“…Figure 3). Obviously a physically correct representation of both singlet states requires a two‐determinantal treatment at least, as does the representation of the 1 Δ state of NH with its strictly degenerate π‐orbitals, which is part of the singlet fragmentation asymptote [15c,71] . In this context we note that these model system singlet species feature all relevant aspects of the electronic intricacies of the full molecular system.…”

Section: Resultsmentioning

confidence: 98%

Another Torture Track for Quantum Chemistry: Reinvestigation of the Benzaldehyde Amidation by Nitrogen‐Atom Transfer from Platinum(II) and Palladium(II) Metallonitrenes

Verplancke

Diefenbach

Lienert

et al. 2023

Israel Journal of Chemistry

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We showcase here a dramatic failure of CCSD(T) theory that originates from the pronounced multi‐reference character of a key intermediate formed in the benzaldehyde amidation by N‐atom transfer from Pd(II) and Pt(II) metallonitrenes studied recently in combined experimental and theoretical work. For detailed analysis we devised a minimal model system, for which we established reliable reference energies based on approximate full configuration interaction theory, to assess the performance of single‐reference coupled‐cluster theory up to the CCSDTQ(P) excitation level. While RHF‐based CCSD(T) theory suffered dramatic errors, in one case exceeding 220 kcal mol−1, we show that the use of broken‐symmetry (BS) or Kohn‐Sham (KS) orbital references yields substantially improved CCSD(T) results. Further, the EOM‐SF‐CCSD(T)(a)* approach met the reference data with excellent accuracy. We applied the KS‐CCSD(T*)‐F12b variant as high‐level part of an ONIOM(KS‐CC:DFT) scheme to reinvestigate the reactivity of the full Pt(II) and Pd(II) metallonitrenes. The revised reaction pathway energetics provide a detailed mechanistic rationale for the experimental observations.

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“…Not so surprisingly, we have the formation of an intramolecular insertion product; however, it only formed in the presence of methanol. Formations of such azirines are well documented for phenyl azide, which exist in resonance with the corresponding ketenimine [ 40 , 41 , 42 ].…”

Section: Photoaffinity Propertiesmentioning

confidence: 99%

Synthesis and Photolysis Properties of a New Chloroquine Photoaffinity Probe

Kapuku,

Bohle

2024

Molecules

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A new chloroquine-derived photoaffinity probe has been prepared by a convergent synthesis from derivative of 4,7-dichloroquinoline and N1,N1-diethyl-N4-methylpentane. The features of this probe are a unique 3-azido photolabel, the pyridine ring of the quinoline, and the presence of a secondary amine at the 4-position of the quinoline. These features, particularly the 4-amino methylation, prevent triazole formation through combination of the 3-azide and the 4-amine. This undergoes facile cleavage with exposure to a medium-pressure mercury lamp with a 254 nm excitation wavelength. Trapping of the nitrene byproduct is accomplished with its reaction with N-phenylmaleimide as its cycloazidation product. The structure of a ring-opened DBU amine has been structurally characterized.

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Theory and Computation in the Study of Nitrenes and their Excited‐State Photoprecursors

Cited by 5 publications

References 152 publications

X-ray Photoelectron Spectroscopy Investigation of the Nitrogen Species in Photoactive Perfluorophenylazide-Modified Surfaces

X-ray Photoelectron Spectroscopy Investigation of the Nitrogen Species in Photoactive Perfluorophenylazide-Modified Surfaces

Another Torture Track for Quantum Chemistry: Reinvestigation of the Benzaldehyde Amidation by Nitrogen‐Atom Transfer from Platinum(II) and Palladium(II) Metallonitrenes

Synthesis and Photolysis Properties of a New Chloroquine Photoaffinity Probe

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