LÖBL, Jiří, Alexey Y. TIMOSHKIN, Cong TRINH, Marek NEČAS, Herbert W. ROESKY and Jiří PINKAS. Alumazene Adducts with Pyridines: Synthesis, Structure, and Stability Studies. INORGANIC CHEMISTRY. Spojené státy americké: American Chemical Society, Washington DC, 2007, vol. 46, No 14, p. 5678-5685. ISSN 0020-1669.
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Basic information
Original name Alumazene Adducts with Pyridines: Synthesis, Structure, and Stability Studies
Name in Czech Adukty alumazenu s pyridiny: příprava, struktura a studium stability
Authors LÖBL, Jiří (203 Czech Republic), Alexey Y. TIMOSHKIN (643 Russian Federation), Cong TRINH (704 Viet Nam), Marek NEČAS (203 Czech Republic), Herbert W. ROESKY (276 Germany) and Jiří PINKAS (203 Czech Republic, guarantor).
Edition INORGANIC CHEMISTRY, Spojené státy americké, American Chemical Society, Washington DC, 2007, 0020-1669.
Other information
Original language English
Type of outcome Article in a journal
Field of Study 10402 Inorganic and nuclear chemistry
Country of publisher United States of America
Confidentiality degree is not subject to a state or trade secret
Impact factor Impact factor: 4.123
RIV identification code RIV/00216224:14310/07:00022391
Organization unit Faculty of Science
UT WoS 000247623000036
Keywords in English Lewis acid-base; adducts; alumazene; pyridine
Tags ADDUCTS, alumazene, Lewis acid-base, Pyridine
Tags International impact, Reviewed
Changed by Changed by: doc. Mgr. Marek Nečas, Ph.D., učo 18809. Changed: 25/6/2009 11:34.
Abstract
Lewis acid-base adducts of the alumazene [2,6-(i-Pr)2C6H3NAlMe]3 (1) with pyridine (py) and 4-dimethylaminopyridine (dmap) were synthesized and structurally characterized: 1(py)2 (2), 1(py)3 (3), 1(dmap)2, (4), and 1(py)(dmap) (5). The bisadducts 2, 4, and 5 form the trans isomers. The trisadduct 3 exhibits an unexpected cis-cis isomer and can be prepared only in the presence of excess py. The planarity of the alumazene ring is lost upon coordination of the Lewis base molecules. A comparison of the Al-N(base) bond distances and pyramidality at Al suggests the higher basicity of dmap. NMR spectroscopy confirms stability to dissociation of the bisadducts in solution while the trisadduct 3 is labile and converts to 2. The thermodynamics of the adduct formation has been investigated experimentally and theoretically. Thermodynamic characteristics of the 1(py)n (n = 2, 3) dissociation reactions in the temperature range 25-200 oC have been derived from the vapor pressure-temperature dependence measurements by the static tensimetric method. In all experiments excess py was employed. Quantum chemical computations at the B3LYP/6-31G* level of theory have been performed for the 1(py)n and model complexes [HAlNH]3(py)n (n = 1-3). Obtained results indicate that for the gas phase adducts upon increasing the number of py ligands the donor-acceptor Al-N(py) distance increases in accord with decreasing donor-acceptor bond dissociation energies.
Abstract (in Czech)
Následující adukty Lewisovsky kyselého alumazenu [2,6-(i-Pr)2C6H3NAlMe]3 (1) s bazemi jako jsou pyridin (py) and 4-dimethylaminopyridin (dmap) byly syntetizovány a strukturně charakterizovány: 1(py)2 (2), 1(py)3 (3), 1(dmap)2, (4), a 1(py)(dmap) (5). Bisadukty 2, 4, a 5 tvoří trans isomery. Trisadukt 3 vytváří neočekávaný cis-cis isomer v přebytku py. Planarita alumazenového kruhu je porušena při koordinaci Lewisovy base. Porovnání Al-N(base) vazebných vzdáleností a pyramidality na Al ukazuje na větší basicitu dmap. NMR spektroskopie potvrdila stabilitu bisaduktu v roztoku, zatímco trisadukt 3 je labilní a odštěpuje py za vzniku 2. Thermodynamické charakteristiky disociačních reakcí 1(py)n (n = 2, 3) v intervalu 25-200 oC byly získány statickou tensimetrickou metodou. Kvantově chemické výpočty (B3LYP/6-31G*) byly provedeny pro 1(py)n a modelové komplexy [HAlNH]3(py)n (n = 1-3). Výsledky ukazují, že u aduktů v plynné fázi se zvyšujícím se počtem py ligandů roste donor-akeptorová Al-N(py) vzdálenost a klesá donor-akeptorová disociační energie vazby.
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MSM0021622410, plan (intention)Name: Fyzikální a chemické vlastnosti pokročilých materiálů a struktur
Investor: Ministry of Education, Youth and Sports of the CR, Physical and chemical properties of advanced materials and structures
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