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71.
Carter J. Holt Katelyn J. Wentworth Richard P. Johnson 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(44):15940-15943
Triangulenes are of current interest for potential applications in molecular electronics. We describe here a three step synthesis of the 4,8,12‐trihydro[3]triangulenium cation by cascade cyclization of a tetra‐benzyl alcohol precursor in triflic acid solution. This stable carbocation is easily observed by NMR and optical spectroscopy and is highly fluorescent. Quenching of the cation into basic solutions or by hydride transfer from triethylsilane provides access to stable dihydro and tetrahydro[3]triangulenes. These neutral species interconvert with cations in a complex series of proton and hydride transfers. This route provides several important [3]triangulene precursors. Preliminary experiments designed to generate [3]triangulene in the solution phase provide evidence for its formation and rapid oligomerization. 相似文献
72.
H. Mkrtchyan P.E. Bosted G.S. Adams A. Ahmidouch T. Angelescu J. Arrington R. Asaturyan O.K. Baker N. Benmouna C. Bertoncini H.P. Blok W.U. Boeglin H. Breuer M.E. Christy S.H. Connell Y. Cui M.M. Dalton S. Danagoulian D. Day T. Dodario J.A. Dunne D. Dutta N. El Khayari R. Ent H.C. Fenker V.V. Frolov L. Gan D. Gaskell K. Hafidi W. Hinton R.J. Holt T. Horn G.M. Huber E. Hungerford X. Jiang M. Jones K. Joo N. Kalantarians J.J. Kelly C.E. Keppel V. Kubarovsky Y. Li Y. Liang S. Malace P. Markowitz E. McGrath P. McKee D.G. Meekins B. Moziak T. Navasardyan 《Physics letters. [Part B]》2008
73.
Dr. Lidia A. Maslovskaya Dr. Andrei I. Savchenko Prof. Elizabeth H. Krenske Dr. Sharon Chow Tina Holt Dr. Victoria A. Gordon Dr. Paul W. Reddell Carly J. Pierce Prof. Peter G. Parsons Prof. Glen M. Boyle Prof. Andrei G. Kutateladze Prof. Craig M. Williams 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(51):11862-11867
Structurally unique halimanes EBC-232 and EBC-323, isolated from the Australian rainforest plant Croton insularis, proved considerably difficult to elucidate. The two diastereomers, which consist an unusual oxo-6,7-spiro ring system fused to a dihydrofuran, were solved by unification and consultation of five in silico NMR elucidation and prediction methods [i.e., ACDLabs, olefin strain energy (OSE), DP4, DU8+ and TD DFT CD]. Structure elucidation challenges of this nature are prime test case examples for empowering future AI learning in structure elucidation. 相似文献
74.
Fatima Erragh Ali Boukhari Brahim Elouadi Elizabeth M. Holt 《Journal of chemical crystallography》1991,21(3):321-326
Na2CoP2O7 may be prepared in two allotropie forms:I, rose,M
r
=278.85, triclinic, P1,a=9.735(2),b=10.940(3),c=12.289(4) Å,=148.78,=121.76(1), =68.38(2)°,V=566.8(2) Å3,Z=4,D
meas=3.28(5) g cm–3,D
calc=3.267 g cm–3, (MoK)=0.71069 Å,=37.12 cm–1, F(000)=540,T=298 K,R=5.4% for 2911 observed reflections; andII, blue,M
r
=278.85, orthorhombic, P21cn,a=7.713(2) Å,b=10.271(4),c=15.378(6)°,V=1218.2(8) Å3,Z=8,D
meas=3.06(5) g cm–3,D
calc=3.040 g cm–1, (MoK
) Å,=34.55 cm–1, F(000)=1080,T=298 K,R=9.9% for 1450 observed reflections. Cobalt displays octahedral coordination to six oxygen atoms in the rose form whereas the metal coordination is tetrahedral in the blue form. 相似文献
75.
Wilton-Ely JD Solanki D Knight ER Holt KB Thompson AL Hogarth G 《Inorganic chemistry》2008,47(20):9642-9653
Treatment of cis-[RuCl2(dppm)2] (dppm = bis(diphenylphosphino)methane) with dithiocarbamates, NaS2CNR2 (R = Me, Et) and [H2NC5H10][S2CNC5H10], yields cations [Ru(S2CNR2)2(dppm)2](+) and [Ru(S2CNC5H10)2(dppm)2](+), respectively. The zwitterions S2CNC4H8NHR (R = Me, Et) react with the same metal complex in the presence of base to yield [Ru(S2CNC4H8NR)(dppm)2](+). Piperazine or 2,6-dimethylpiperazine reacts with carbon disulfide to give the zwitterionic dithiocarbamate salts H2NC4H6(R2-3,5)NCS2 (R = H; R = Me), which form the complexes [Ru(S2CNC4H6(R2-3,5)NH2)(dppm)2](2+) on reaction with cis-[RuCl2(dppm)2]. Sequential treatment of [Ru(S2CNC4H8NH2)(dppm)2](2+) with triethylamine and carbon disulfide forms the versatile metalla-dithiocarbamate complex [Ru(S2CNC4H8NCS2)(dppm)2] which reacts readily with cis-[RuCl2(dppm)2] to yield [{Ru(dppm)2}2(S2CNC4H8NCS2)]. Reaction of [Ru(S2CNC4H8NCS2)(dppm)2] with [Os(CH=CHC6H4Me-4)Cl(CO)(BTD)(PPh3)2] (BTD = 2,1,3-benzothiadiazole), [Pd(C6H4CH2NMe2)Cl]2, [PtCl2(PEt3)2], and [NiCl2(dppp)] (dppp = 1,3-bis(diphenylphosphino)propane) results in the heterobimetallic complexes [(dppm)2Ru(S2CNC4H8NCS2)ML(n))](m+) (ML(n) = Os(CH=CHC6H4Me-4)(CO)(PPh3)2](+), m = 1; ML(n) = Pd(C,N-C6H4CH2NMe2), m = 1; ML(n) = Pt(PEt3)2, m = 2; ML(n) = Ni(dppp), m = 2). Reaction of [NiCl2(dppp)] with H2NC4H8NCS2 yields the structurally characterized compound, [Ni(S2CNC4H8NH2)(dppp)](2+), which reacts with base, CS2, and cis-[RuCl2(dppm)2] to provide an alternative route to [(dppm)2Ru(S2CNC4H8NCS2)Ni(dppp)](+). A further metalla-dithiocarbamate based on cobalt, [CpCo(S2CNC4H8NH2)(PPh3)](2+), is formed by treatment of CpCoI2(CO) with S2CNC4H8NH2 followed by PPh3. Further reaction with NEt3, CS2, and cis-[RuCl2(dppm)2] yields [(Ph3P)CpCo(S2CNC4H8NCS2)Ru(dppm)2](2+). Heterotrimetallic species of the form [{(dppm)2Ru(S2CNC4H8NCS2)}2M](2+) result from the reaction of [Ru(S2CNC4H8NCS2)(dppm)2] and M(OAc)2 (where M = Ni, Cu, Zn). Reaction of [Ru(S2CNC4H8NCS2)(dppm)2] with Co(acac)3 and LaCl3 results in the formation of the compounds [{(dppm)2Ru(S2CNC4H8NCS2)}3Co](3+) and [{(dppm)2Ru(S2CNC4H8NCS2)}3La](3+), respectively. The electrochemical behavior of selected examples is also reported. 相似文献
76.
Laura Ciobanu Susan Hermiller Derek Holt Sarah Rees 《Israel Journal of Mathematics》2016,211(1):311-347
We study the regularity of several languages derived from conjugacy classes in a finitely generated group G for a variety of examples including word hyperbolic, virtually abelian, Artin, and Garside groups. We also determine the rationality of the growth series of the shortlex conjugacy language in virtually cyclic groups, proving one direction of a conjecture of Rivin. 相似文献
77.
78.
Holt JJ Calitree BD Vincek J Gannon MK Detty MR 《The Journal of organic chemistry》2007,72(7):2690-2693
9-formyljulolidine was oxidized via a microwave-assisted Willgerodt-Kindler reaction to the N-piperidine or N-morpholine julolidine-9-thioamide. 9-formyl-1,1,7,7-tetramethyljulolidine gave the corresponding N-piperidine tetramethyljulolidine-9-thioamide. The thioamides were converted to the corresponding carboxamides with trifluoroacetic anhydride. The amide group directed ortho-metalation in the julolidine system, but not in the tetramethyljulolidine system. The resulting anion was captured by dichalcogenide electrophiles. The resulting products were converted to chalcogenoxanthones with phosphorus oxychloride and triethylamine (POCl3/Et3N). 相似文献
79.
The non-stoichiometry and chemical diffusion coefficient of SrFe1−xCoxO3-δ have been measured by steady state and transient thermogravimetry in the temperature range 750–1200 °C at different oxygen
partial pressures. At high oxygen partial pressures, the chemical diffusion coefficient was in the range 1·10−4 – 7·10−4 cm2/s. This, combined with high concentration of disordered vacancies make these materials perhaps the fastest solid oxygen ion
diffusers known at high temperatures and high oxygen partial pressures. However, due to the high concentration of defects
in SrFe1−xCoxO3-δ the compound transforms from a cubic (disordered) perovskite to a brownmillerite type of structure under reduced oxygen partial
pressures below approx. 900 °C. Due to this phase transition, the mobility of oxygen vacancies in SrFe1−xCoxO3-δ decreases up to about an order of magnitude at 850 °C. We also observe an ordering effect at 1000 °C, although smaller in
size, and this is suggested to be due to short range ordering of four-coordinated polyhedra of Fe. For possible use as oxygen
separation membranes, phase stability against sulphur and carbon containing atmospheres is also discussed with respect to
the formation of carbonates and sulphates.
Paper presented at the 6th Euroconference on Solid State Ionics, Cetraro, Calabria, Italy, Sept. 12–19, 1999. 相似文献
80.
David J. Holt William D. Barker Paul R. Jenkins David L. Davies Shaun Garratt John Fawcett David R. Russell Subtrata Ghosh 《Angewandte Chemie (International ed. in English)》1998,37(23):3298-3300
Even eight-membered rings (such as in 2 ) can be formed by ring-closing metathesis of glucose derivatives such as 1 . Enantiomerically pure tricyclic spiro compounds can also be prepared. 相似文献