Photophysical properties of some 2-(2'-hydroxyaryl)benzotriazoles: dramatic effect of an ortho-located bulky tert-butyl group

1992 ◽  
Vol 114 (3) ◽  
pp. 964-966 ◽  
Author(s):  
Javier Catalan ◽  
Pilar Perez ◽  
Fernando Fabero ◽  
John F. K. Wilshire ◽  
Rosa Maria Claramunt ◽  
...  
Keyword(s):  
Photophysical Properties ◽  
Dramatic Effect ◽  
Tert Butyl ◽  
Butyl Group ◽  
Tert Butyl Group

ChemInform Abstract: Photophysical Properties of Some 2-(2′-Hydroxyaryl)benzotriazoles: Dramatic Effect of an Ortho-Located Bulky tert-Butyl Group.

ChemInform ◽  
2010 ◽  
Vol 23 (23) ◽  
pp. no-no
Author(s):  
J. CATALAN ◽  
P. PEREZ ◽  
F. FABERO ◽  
J. F. K. WILSHIRE ◽  
R. MA. CLARAMUNT ◽  
...  
Keyword(s):  
Photophysical Properties ◽  
Dramatic Effect ◽  
Tert Butyl ◽  
Butyl Group ◽  
Tert Butyl Group

scholarly journals Syntheses and Characterizations of Platinum Complexes with New Pyrene-based Salicylaldiminato-type Ligand Substituted at 7-Position of Pyrene

2021 ◽  
Vol 10 (2) ◽  
pp. 26-35
Author(s):  
Dien Luong Xuan
Keyword(s):  
Photophysical Properties ◽  
Emission Spectra ◽  
Platinum Complexes ◽  
X Ray Diffraction ◽  
Absorption And Emission ◽  
Absorption And Emission Spectra ◽  
Tert Butyl ◽  
Imine Group ◽  
Butyl Group ◽  
Tert Butyl Group

Many experimental data show that bulky substituents on the molecules enhance solubility, catalytic activity, and photophysical properties due to the prevention of π-π stacking in metal salicylaldimines. In order to understand the effect of bulkiness of substituents on the properties of the obtained molecules, the author researched and synthesized two new pyrene-based salicylaldiminato-type ligands that were substituted at 7-position and functionalized on imine group with bulky substituents. After the introduction of  the tert-butyl group at 7-position of pyrene by Friedel-Crafts reaction, the syntheses of new ligands 1-hydroxy-2-[((2,6-dimethylphenyl)-imino)methyl]-7-(tert-butyl)-pyrene 3, 2-hydroxy-1- [((2,6-dimethylphenyl)imino)methyl]-7-(tert-butyl)-pyrene 4 and corresponding platinum complexes 3(Pt), 4(Pt) were performed in the different ways with the synthetic processes of the complexes 1(Pt) and 2(Pt). The new ligands and complexes were characterized by 1H NMR, IR spectroscopy, mass spectroscopy, elemental analysis and X-ray diffraction, only for 3(Pt). In addition to measurements of the absorption and emission spectra, TDDFT calculations using the B3LYP functions were also performed. The complexes 3(Pt) and 4(Pt) exhibit good solubility and red-shift in absorption and emission spectra because of tert-butyl group at 7-position of pyrene and extension of the delocalized π-orbitals to the 2,6-dimethylphenyl on imine group. The change of functional groups also induces the upfield shift of the protons affected by ring currents of phenyl groups Ar-3, Ar-4 on imine groups. Introduction of t-butyl groups in pyrene moieties can stabilize radical forms in oxidation processes.

Medium-sized cyclophanes, part 59:1 Nitration of [3.3]- and [3.3.3]metacyclophanes — Through-space electronic interactions between two or three benzene rings

2002 ◽  
Vol 80 (2) ◽  
pp. 207-215 ◽  
Author(s):  
Takehiko Yamato ◽  
Koji Tsuchihashi ◽  
Noriko Nakamura ◽  
Mai Hirahara ◽  
Hirohisa Tsuzuki
Keyword(s):  
Acetic Anhydride ◽  
Electronic Interaction ◽  
Reaction Conditions ◽  
Tert Butyl ◽  
Mixed Acid ◽  
Butyl Group ◽  
Tert Butyl Group ◽  
Starting Compound ◽  
Nitration Product ◽  
Fuming Nitric Acid

The two tert-butyl groups of anti-6,15-di-tert-butyl-9,18-dimethoxy[3.3]metacyclophane (anti-4) are both ipso-nitrated even under mild reaction conditions such as copper(II) nitrate in an acetic anhydride solution because of the decreased deactivation of the second aromatic ring by the introduced nitro group. On the other hand, anti-5,13-di-tert-butyl-8,16-dimethoxy[2.2]metacyclophane (anti-1) undergoes replacement of only one tert-butyl group under the same reaction conditions. The higher yields of the twofold ipso-nitration product anti-7 were obtained in nitration of anti-4 with fuming nitric acid or mixed acid (HNO3–H2SO4). Thus, the number of ipso-nitrations at the tert-butyl groups of anti-4 was strongly affected by the reactivity of the nitration reagent. Nitration of the corresponding syn-conformer syn-4 with copper(II) nitrate in an acetic anhydride solution, however, led only to the recovery of the starting compound. The presently developed procedure was further applied to the direct removal of the tert-butyl group by electrophilic substitution of the larger-sized ring macrocyclic metacyclophanes, cone- and partial-cone-tri-tert-butyl[3.3.3]metacyclophanes 11.Key words: [3n]metacyclophanes, conformation, ipso-nitration, through-space electronic interaction, crystal structure.

Reactions of benzyl methyl substituted-benzyl phosphites with tert-butyl hypochlorite: "balanced TS" validating reactivity/selectivity principle

1998 ◽  
Vol 76 (6) ◽  
pp. 836-842
Author(s):  
Sung Soo Kim ◽  
Yu Zhu ◽  
In Seok Oh ◽  
Chang Gyeong Lim
Keyword(s):  
Benzyl Chloride ◽  
Activation Parameters ◽  
Differential Activation ◽  
Tert Butyl ◽  
Benzyl Chlorides ◽  
Butyl Group ◽  
Tert Butyl Group ◽  
Polar Transition ◽  
Isokinetic Relations ◽  
Selectivity Principle

Reactions of a series of several benzyl methyl substituted-benzyl phosphites with tert-butyl hypochlorite were investigated. The reactions produced phosphates, isobutene, alkyl chlorides, and benzyl chlorides via phosphonium chlorides as intermediates. Furthermore, the phosphates bearing a tert-butyl group underwent fragmentation to yield isobutene and another phosphates. Relative rates of formations of substituted benzyl and benzyl chloride (kY/kH) were measured at the temperatures (-20, 0, 20, 40°C). Logarithms of the rates (log kY/kH) were plotted against sigma + and 1/T, respectively. The former gave Hammett correlations to suggest a polar transition state (TS). The latter yielded differential activation parameters (ΔΔ Hdouble daggerY-H and ΔΔ Sdouble daggerY-H ), which indicate isokinetic relations and enthalpy control of rates. The selectivities (kY/kH) decrease with higher temperatures and thereby follow the reactivity/selectivity principle.Key words: phosphites, tert-butyl hypochlorite, Hammett correlations, differential activation terms, reactivity/selectivity principle.

Evaluation of the tert-butyl group as a probe for NMR studies of macromolecular complexes

2021 ◽  
Author(s):  
Rashmi Voleti ◽  
Sofia Bali ◽  
Jaime Guerrero ◽  
Jared Smothers ◽  
Charis Springhower ◽  
...  
Keyword(s):  
Nmr Studies ◽  
Macromolecular Complexes ◽  
Tert Butyl ◽  
Butyl Group ◽  
Tert Butyl Group

Michael addition of amines to sterically crowded ortho-benzoquinone completed with unprecedented 1,2-shift of a tert-butyl group

Tetrahedron ◽  
2021 ◽  
Vol 79 ◽  
pp. 131841
Author(s):  
Eugeny Ivakhnenko ◽  
Vasily Malay ◽  
Galina Romanenko ◽  
Oleg Demidov ◽  
Pavel Knyazev ◽  
...  
Keyword(s):  
Michael Addition ◽  
Tert Butyl ◽  
Butyl Group ◽  
Tert Butyl Group

Tri(Terf-Butyl)plumbyl-phosphanes, Synthesis and Multinuclear Magnetic Resonance

2000 ◽  
Vol 55 (10) ◽  
pp. 939-945 ◽  
Author(s):  
Max Herberhold ◽  
Christian Köhler ◽  
Volker Tröbs ◽  
Bernd Wrackmeyer
Keyword(s):  
Magnetic Resonance ◽  
Phosphorus Atom ◽  
Coupling Constants ◽  
Tert Butyl ◽  
Nmr Data ◽  
Butyl Group ◽  
Tert Butyl Group ◽  
Multinuclear Magnetic Resonance

AbstractThe reaction of tri(tert-butyl)plumbyl-lithium (1) with various phosphorus chlorides was studied. With diphenyl- and amino(phenyl)phosphorus chlorides the formation of hexa(tertbutyl) diplumbane (2) and tetraphenyldiphosphane (3) or the respective 1,2-bis(am ino)-1,2-diphenyl- diphosphanes [e. g. 5: amino = PhCH2(tBu)N] was dominant. The presence of at least one tert-butyl group at the phosphorus atom gave access to tri(tert-butyl)plumbyl-di(tert-butyl) phosphane (4) and to tri(tert-butyl)plumbyl-amino(tert-butyl)phosphanes [amino = tBu(H)N (6), Me(Ph)N (7), PhCH2(Me)N (8), PhCH2(tBu)N (9)] via the reaction of 1 with the corresponding phosphorus chlorides. Side products were again 2 and the corresponding diphosphanes, unidentified compounds, and in two cases, bis(phosphanyl)-di(tert-butyl)plumbanes [phosphanyl = tBu(H)N(tBu)P (10), Me(Ph)N(tBu)P (11)]. Trimethylplumbyl-benzyl(methyl)- amino(tert-butyl)phosphane (12) was prepared for comparison. All compounds were characterized by their 1H , 13C, 15N (9 ),31P and 207Pb NMR data. The coupling constants 1J(207Pb,31P) are large and negative, whereas the coupling constants 1J(207Pb, 13C) are small and can be of either sign. The coupling constants 2J(31P-N-13C) of 6 - 12 indicate a preferred conformation of the substituents at phosphorus and nitrogen

ChemInform Abstract: A CASE OF A FACILE CLEAVAGE OF AN ANGULAR TERT-BUTYL GROUP

1981 ◽  
Vol 12 (28) ◽  
Author(s):  
V. A. KAMINSKII ◽  
T. V. ZABOLOTNOVA ◽  
T. V. NOVIKOVA ◽  
T. M. TILICHENKO
Keyword(s):  
Tert Butyl ◽  
Butyl Group ◽  
Tert Butyl Group

The tert-butyl group in chemistry and biology

2008 ◽  
Vol 6 (15) ◽  
pp. 2655 ◽  
Author(s):  
Philippe Bisel ◽  
Loay Al-Momani ◽  
Michael Müller
Keyword(s):  
Tert Butyl ◽  
Butyl Group ◽  
Tert Butyl Group

Synthesis of 1-tert-Butyl-4-chloropiperidine:  Generation of anN-tert-Butyl Group by the Reaction of a Dimethyliminium Salt with Methylmagnesium Chloride

2005 ◽  
Vol 70 (5) ◽  
pp. 1930-1933 ◽  
Author(s):  
Joseph S. Amato ◽  
John Y. L. Chung ◽  
Raymond J. Cvetovich ◽  
Xiaoyi Gong ◽  
Mark McLaughlin ◽  
...  
Keyword(s):  
Tert Butyl ◽  
Butyl Group ◽  
Tert Butyl Group
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