- Crystalline Monomeric Allenyl/Propargyl Radical
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Reduction of alkynyl iminium salts derived from cyclic (alkyl)(amino)carbenes (CAACs) affords propargyl/allenyl radicals. Depending on the nature of the CAAC and alkyne substituents, these radicals can irreversibly dimerize, exist as monomers in solution
- Hansmann, Max M.,Melaimi, Mohand,Bertrand, Guy
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- Molecular "compasses" and "gyroscopes". I. Expedient synthesis and solid state dynamics of an open rotor with a bis(triarylmethyl) frame
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We describe our efforts toward the preparation of materials built with molecules possessing topologies analogous to those of macroscopic compasses and gyroscopes. Samples of 1,4-bis(3,3,3-triphenylpropynyl)benzene (3) were prepared by a simple two-step pr
- Dominguez, Zaira,Dang, Hung,Strouse, M. Jane,Garcia-Garibay, Miguel A.
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- Crystals and aggregates of a molecular tetrarotor with multiple trityl embraces derived from tetraphenyladamantane
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Samples of tetrakis-1,3,5,7-(4′-(3″,3″,3″- triphenylpropynyl)-phenylene)adamantane and its trityl-deuterated isotopologue were synthesized and their crystallization and packing properties were analyzed within the context of formation of 4- or 6-fold phenyl embraces. The tetrahedral shape of these molecules with four propeller-like triphenylmethyl moieties generates several edge-to-face intermolecular interactions in the solid state that result in the formation of infinite chains of molecules that are tightly interlocked. The formation of analogous edge-to-face intermolecular interactions leading to aggregation in solution was also suggested by NMR experiments carried out in different solvents as a function of concentration. The formation of interdigitated chains was also manifested in fibrils and thin needles, which were documented by scanning electron microscopy (SEM). Single crystal X-ray diffraction studies revealed the presence of multiple 4-fold phenyl embraces and edge-to-face interactions as the leading motifs behind the formation of tightly interlocked molecular chains.
- Stopin, Antoine,Garcia-Garibay, Miguel A.
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scheme or table
p. 3792 - 3798
(2012/10/18)
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- Synthesis, characterization, and rotational dynamics of crystalline molecular compasses with N-heterocyclic rotators
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(Figure Presented) We describe in this paper the synthesis, crystallization, and solid-state NMR dynamics of molecules intended to emulate the structure and function of macroscopic compasses. The desired structures consist of polar pyridine (2) and pyrida
- Rodriguez-Molina, Braulio,Ochoa, Ma. Eugenia,Farfan, Norberto,Santillan, Rosa,Garcia-Garibay, Miguel A.
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supporting information; experimental part
p. 8554 - 8565
(2010/02/28)
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- Effects of rotational symmetry order on the solid state dynamics of phenylene and diamantane rotators
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The rotational dynamics of phenylene and diamantane rotators in crystals of 1,9-bis(4-[3,3,3-triphenylpropynyl]phenyl)diamantane were analyzed independently within the same crystal structure. The dynamics of phenylene rotation were established by dynamic line shape analysis using 13C CPMAS NMR. The phenylene signals were selectively highlighted by deuteration of the aromatic trityls and the use of short contact times for cross polarization. The dynamics of the diamantane group were established by 1H spin-lattice relaxation under conditions where dipolar relaxation was shown to be the dominant mechanism between 250 and 425 K. A factor of 20000 between the rates of rotation of the faster diamantane and the slower phenylene at 300 K supports expectations that higher symmetry rotors should have significantly faster dynamics. Copyright
- Karlen, Steven D.,Ortiz, Rafael,Chapman, Orville L.,Garcia-Garibay, Miguel A.
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p. 6554 - 6555
(2007/10/03)
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- Molecular "compasses" and "gyroscopes." III. Dynamics of a phenylene rotor and clathrated benzene in a slipping-gear crystal lattice
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Samples of 1,4-bis(3,3,3-triphenylpropynyl)benzene 3 were prepared by Pd(0)-catalyzed coupling of 3,3,3-triphenylpropyne (1) and 1,4-diiodobenzene. The structure of compound 3 is such that the central phenylene can play the role of a gyroscope wheel, whil
- Dominguez, Zaira,Dang, Hung,Strouse, M. Jane,Garcia-Garibay, Miguel A.
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p. 7719 - 7727
(2007/10/03)
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