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Curt Wentrup - One of the best experts on this subject based on the ideXlab platform.
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Iminopropadienones RN=C=C=C=O and bisiminopropadienes RN=C=C=C=NR: Matrix infrared speCtra and anharmoniC frequenCy CalCulations
Journal of Chemical Physics, 2013Co-Authors: Didier Begue, Heidi Gade Andersen, Isabelle Baraille, Curt WentrupAbstract:Methyliminopropadienone MeN=C=C=C=O 1a was generated by flash vaCuum thermolysis from four different preCursors and isolated in solid argon. The matrix-isolation infrared speCtrum is dominated by unusually strong anharmoniC effeCts resulting in Complex fine struCture of the absorptions due to the NCCCO moiety in the 2200 Cm−1 region. Doubling and tripling of the Corresponding absorption bands are observed for phenyliminopropadienone PhN=C=C=C=O 1b and bis(phenylimino)propadiene PhN=C=C=C=NPh 9, respeCtively. AnharmoniC vibrational frequenCy CalCulations allow the identifiCation of a number of overtones and Combination bands as the Cause of the splittings for eaCh moleCule. This method Constitutes an important tool for the CharaCterization of reaCtive intermediates and unusual moleCules by matrix-isolation infrared speCtrosCopy.
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Iminopropadienones RN=C=C=C=O and bisiminopropadienes RN=C=C=C=NR: Matrix infrared speCtra and anharmoniC frequenCy CalCulations.
Journal of Chemical Physics, 2013Co-Authors: Didier Begue, Heidi Gade Andersen, Isabelle Baraille, Curt WentrupAbstract:Methyliminopropadienone MeN=C=C=C=O 1a was generated by flash vaCuum thermolysis from four different preCursors and isolated in solid argon. The matrix-isolation IR speCtrum is dominated by unusually strong anharmoniC effeCts resulting in Complex fine struCture of the absorptions due to the NCCCO moiety in the 2200 Cm-1 region. Doubling and tripling of the Corresponding absorption bands are obsd. for phenyliminopropadienone PhN=C=C=C=O 1b and bis(phenylimino)propadiene PhN=C=C=C=NPh 9, resp. AnharmoniC vibrational frequenCy CalCns. allow the identifiCation of a no. of overtones and Combination bands as the Cause of the splittings for eaCh mol. This method Constitutes an important tool for the CharaCterization of reaCtive intermediates and unusual mols. by matrix-isolation IR speCtrosCopy.
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Thioketenes and Iminopropadienethiones RN=C=C=C=S from Isoxazolones
Australian Journal of Chemistry, 2010Co-Authors: David Kvaskoff, Curt WentrupAbstract:Isoxazolones 6 undergo thermal elimination of propene and isopropylthiol to produCe thioketenes 7 at 500–600°C under flash vaCuum thermolysis Conditions. At 700–900°C further fragmentation oCCurs to produCe iminopropadienethiones, RNCCCS 8. In addition, 3-alkylisoxazolones 6d–e rearrange to Cyanothioketenes 10d–e. Compounds 7, 8, and 10 were CharaCterized by Ar matrix IR speCtrosCopy and Comparison with density funCtional theory-CalCulated speCtra. Thioketenes 7 reaCted with amines to afford thioamides 11. ReaCtion of aryliminopropadienethiones 8 with amines Caused CyClization to 2-aminoquinoline-4(1H)-thiones 16.
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Linear ketenimines. Variable struCtures of C,C-diCyanoketenimines and C,C-bis-sulfonylketenimines.
Journal of Organic Chemistry, 2002Co-Authors: Justin J Finnerty, Ullrich Mitschke, Curt WentrupAbstract:C,C-DiCyanoketenimines 10a-C were generated by flash vaCuum thermolysis of ketene NS-aCetals 9a-C or by thermal or photoChemiCal deComposition of alpha-azido-,beta-CyanoCinnamonitrile 11. In the latter reaCtion, 3,3-diCyano-2-phenyl-1-azirine 12 is also formed. IR speCtrosCopy of the keteniminines isolated in Ar matrixes or as neat films, NMR speCtrosCopy of 10C, and theoretiCal CalCulations (B3LYP/6-31G*) demonstrate that these ketenimines have variable geometry, being essentially linear along the CCN-R framework in polar media (neat films and solution), but in the gas phase or Ar matrix they are bent, as is usual for ketenimines. Experiments and CalCulations agree that a single CN substituent as in 13 is not enough to enforCe linearity, and sulfonyl groups are less effeCtive that Cyano groups in Causing linearity. C,C-Bis(methylsulfonyl)ketenimines 4-5 and a C-Cyano-C-(methylsulfonyl)ketenimine 15 are not linear. The Compound p-O2NC6H4N=C= C(COOMe)2 previously reported in the literature is probably somewhat linearized along the CCNR moiety. A Computational survey (B3LYP/6-31G*) of the inversion barrier at nitrogen indiCates that eleCtronegative C-substituents dramatiCally lower the barrier; this is also true of N-aCyl substituents. InCreasing polarity Causes lower barriers. Although N-alkylbis(methylsulfonyl)ketenimines are not CalCulated to be linear, the barriers are so low that Crystal lattiCe forCes Can induCe planarity in N-methylbis(methylsulfonyl)ketenimine 3.
Kung-kai Cheung - One of the best experts on this subject based on the ideXlab platform.
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Synthesis and LuminesCenCe Behavior of Rhenium(I) Triynyl Complexes. X-ray Crystal StruCtures of [Re(CO)3(tBu2bpy)(C⋮C−C⋮C−C⋮CPh)] and [Re(CO)3(Me2bpy)(C⋮C−C⋮C−C⋮CSiMe3)]
Organometallics, 2000Co-Authors: Samuel Hung-fai Chong, Chi-chiu Ko, Kung-kai CheungAbstract:LuminesCent rhenium(I) triynyl Complexes [Re(CO)3(tBu2bpy)(C⋮C−C⋮C−C⋮CPh)] 1, [Re(CO)3(tBu2bpy)(C⋮C−C⋮C−C⋮CSiMe3)] 2, and [Re(CO)3(Me2bpy)(C⋮C−C⋮CC⋮CSiMe3)] 3, were synthesized and their photophysiCal and eleCtroChemiCal properties studied. The X-ray Crystal struCtures of 1 and 3 have also been determined. A Comparison study of their emission properties to that of their mono- and diynyl analogues was made and their emission origin suggested and supported by EHMO studies.
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Synthesis and LuminesCenCe Behavior of Rhenium(I) Triynyl Complexes. X-ray Crystal StruCtures of [Re(CO)3(tBu2bpy)(C⋮C−C⋮C−C⋮CPh)] and [Re(CO)3(Me2bpy)(C⋮C−C⋮C−C⋮CSiMe3)]
Organometallics, 2000Co-Authors: Vivian Wing-wah Yam, Samuel Hung-fai Chong, Kung-kai CheungAbstract:LuminesCent rhenium(I) triynyl Complexes [Re(CO)3(tBu2bpy)(C⋮C−C⋮C−C⋮CPh)] 1, [Re(CO)3(tBu2bpy)(C⋮C−C⋮C−C⋮CSiMe3)] 2, and [Re(CO)3(Me2bpy)(C⋮C−C⋮CC⋮CSiMe3)] 3, were synthesized and their photophysi...
Giovanni Poli - One of the best experts on this subject based on the ideXlab platform.
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SwitChable seleCtivity in Pd-Catalyzed [3 + 2] annulations of γ-oxy-2-CyCloalkenones with 3-oxoglutarates: C-C/C-C vs C-C/O-C bond formation.
Beilstein Journal of Organic Chemistry, 2019Co-Authors: Julie Oble, Giovanni PoliAbstract:Two Complementary [3 + 2] annulation protoCols between 3-oxoglutarates and CyCliC γ-oxy-2-CyCloalkenones, simply differing on the reaCtion temperature, are disClosed. These domino transformations allow C–C/O–C or C–C/C–C [3 + 2] annulations at will, via an intermoleCular Pd-Catalyzed C-allylation/intramoleCular O- or C-1,4-addition sequenCe, respeCtively. In partiCular, exploiting the reversibility of the O-1,4-addition step, in Combination with the irreversible C-1,4-addition/deCarboxylation path, the intramoleCular Conjugate addition step Could be diverted from the kinetiC (O-alkylation) to the thermodynamiC path (C-alkylation) thanks to a simple temperature inCrease. CruCial for the suCCess of this bis-nuCleophile/bis-eleCtrophile [3 + 2] annulation is its well-defined step Chronology in Combination with the total ChemoseleCtivity of the former step. This [3 + 2] C–C/O–C bond forming annulation protoCol Could be also extended to 1,3,5-triketones as well as 1,3-bis-sulfonylpropan-2-one bis-nuCleophiles.
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SwitChable seleCtivity in Pd-Catalyzed [3 + 2] annulations of γ-oxy-2-CyCloalkenones with 3-oxoglutarates: C–C/C–C vs C–C/O–C bond formation
Beilstein-Institut, 2019Co-Authors: Yang Liu, Julie Oble, Giovanni PoliAbstract:Two Complementary [3 + 2] annulation protoCols between 3-oxoglutarates and CyCliC γ-oxy-2-CyCloalkenones, simply differing on the reaCtion temperature, are disClosed. These domino transformations allow C–C/O–C or C–C/C–C [3 + 2] annulations at will, via an intermoleCular Pd-Catalyzed C-allylation/intramoleCular O- or C-1,4-addition sequenCe, respeCtively. In partiCular, exploiting the reversibility of the O-1,4-addition step, in Combination with the irreversible C-1,4-addition/deCarboxylation path, the intramoleCular Conjugate addition step Could be diverted from the kinetiC (O-alkylation) to the thermodynamiC path (C-alkylation) thanks to a simple temperature inCrease. CruCial for the suCCess of this bis-nuCleophile/bis-eleCtrophile [3 + 2] annulation is its well-defined step Chronology in Combination with the total ChemoseleCtivity of the former step. This [3 + 2] C–C/O–C bond forming annulation protoCol Could be also extended to 1,3,5-triketones as well as 1,3-bis-sulfonylpropan-2-one bis-nuCleophiles
Samuel Hung-fai Chong - One of the best experts on this subject based on the ideXlab platform.
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Synthesis and LuminesCenCe Behavior of Rhenium(I) Triynyl Complexes. X-ray Crystal StruCtures of [Re(CO)3(tBu2bpy)(C⋮C−C⋮C−C⋮CPh)] and [Re(CO)3(Me2bpy)(C⋮C−C⋮C−C⋮CSiMe3)]
Organometallics, 2000Co-Authors: Samuel Hung-fai Chong, Chi-chiu Ko, Kung-kai CheungAbstract:LuminesCent rhenium(I) triynyl Complexes [Re(CO)3(tBu2bpy)(C⋮C−C⋮C−C⋮CPh)] 1, [Re(CO)3(tBu2bpy)(C⋮C−C⋮C−C⋮CSiMe3)] 2, and [Re(CO)3(Me2bpy)(C⋮C−C⋮CC⋮CSiMe3)] 3, were synthesized and their photophysiCal and eleCtroChemiCal properties studied. The X-ray Crystal struCtures of 1 and 3 have also been determined. A Comparison study of their emission properties to that of their mono- and diynyl analogues was made and their emission origin suggested and supported by EHMO studies.
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Synthesis and LuminesCenCe Behavior of Rhenium(I) Triynyl Complexes. X-ray Crystal StruCtures of [Re(CO)3(tBu2bpy)(C⋮C−C⋮C−C⋮CPh)] and [Re(CO)3(Me2bpy)(C⋮C−C⋮C−C⋮CSiMe3)]
Organometallics, 2000Co-Authors: Vivian Wing-wah Yam, Samuel Hung-fai Chong, Kung-kai CheungAbstract:LuminesCent rhenium(I) triynyl Complexes [Re(CO)3(tBu2bpy)(C⋮C−C⋮C−C⋮CPh)] 1, [Re(CO)3(tBu2bpy)(C⋮C−C⋮C−C⋮CSiMe3)] 2, and [Re(CO)3(Me2bpy)(C⋮C−C⋮CC⋮CSiMe3)] 3, were synthesized and their photophysi...
Julie Oble - One of the best experts on this subject based on the ideXlab platform.
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SwitChable seleCtivity in Pd-Catalyzed [3 + 2] annulations of γ-oxy-2-CyCloalkenones with 3-oxoglutarates: C-C/C-C vs C-C/O-C bond formation.
Beilstein Journal of Organic Chemistry, 2019Co-Authors: Julie Oble, Giovanni PoliAbstract:Two Complementary [3 + 2] annulation protoCols between 3-oxoglutarates and CyCliC γ-oxy-2-CyCloalkenones, simply differing on the reaCtion temperature, are disClosed. These domino transformations allow C–C/O–C or C–C/C–C [3 + 2] annulations at will, via an intermoleCular Pd-Catalyzed C-allylation/intramoleCular O- or C-1,4-addition sequenCe, respeCtively. In partiCular, exploiting the reversibility of the O-1,4-addition step, in Combination with the irreversible C-1,4-addition/deCarboxylation path, the intramoleCular Conjugate addition step Could be diverted from the kinetiC (O-alkylation) to the thermodynamiC path (C-alkylation) thanks to a simple temperature inCrease. CruCial for the suCCess of this bis-nuCleophile/bis-eleCtrophile [3 + 2] annulation is its well-defined step Chronology in Combination with the total ChemoseleCtivity of the former step. This [3 + 2] C–C/O–C bond forming annulation protoCol Could be also extended to 1,3,5-triketones as well as 1,3-bis-sulfonylpropan-2-one bis-nuCleophiles.
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SwitChable seleCtivity in Pd-Catalyzed [3 + 2] annulations of γ-oxy-2-CyCloalkenones with 3-oxoglutarates: C–C/C–C vs C–C/O–C bond formation
Beilstein-Institut, 2019Co-Authors: Yang Liu, Julie Oble, Giovanni PoliAbstract:Two Complementary [3 + 2] annulation protoCols between 3-oxoglutarates and CyCliC γ-oxy-2-CyCloalkenones, simply differing on the reaCtion temperature, are disClosed. These domino transformations allow C–C/O–C or C–C/C–C [3 + 2] annulations at will, via an intermoleCular Pd-Catalyzed C-allylation/intramoleCular O- or C-1,4-addition sequenCe, respeCtively. In partiCular, exploiting the reversibility of the O-1,4-addition step, in Combination with the irreversible C-1,4-addition/deCarboxylation path, the intramoleCular Conjugate addition step Could be diverted from the kinetiC (O-alkylation) to the thermodynamiC path (C-alkylation) thanks to a simple temperature inCrease. CruCial for the suCCess of this bis-nuCleophile/bis-eleCtrophile [3 + 2] annulation is its well-defined step Chronology in Combination with the total ChemoseleCtivity of the former step. This [3 + 2] C–C/O–C bond forming annulation protoCol Could be also extended to 1,3,5-triketones as well as 1,3-bis-sulfonylpropan-2-one bis-nuCleophiles