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221.
Annibale Giuliano Marangoni Giampaolo Pitteri Bruno Visentin Fabiano Bobbo Tatiana 《Transition Metal Chemistry》2000,25(4):485-489
The reactions of AuIII, PtII and PdII complexes with 2-pyridinecarboxaldehyde (2CHO-py) have been examined in protic (H2O, MeOH, EtOH) and aprotic (DMF, CH2Cl2) solvents. Compounds in which the pyridine ligand is N-coordinated, either in the original aldehydic form or in a new form
derived from addition of one or two protic molecules, have been isolated, namely: [Au(2CHO-py · H2O)Cl3], [Au(2CHO-py · MeOH)Cl3], [Au(2CHO-py · 2EtOH)Cl3], cis-[Pt(2CHO-py)2Cl2], trans-[Pd(2CHO-py)2Cl2], trans-[Pt(dmso)(2CHO-py)Cl2], [Pt{C5H4N-(CH2SMe)}Cl(2CHO-py)](ClO4), [Pt(terpy)(2CHOpy)](ClO4)2, [Pt(terpy)(2CHO-py · H2O)](ClO4)2 (terpy = 2,2′:6′,2′′-terpyridine). 1H-n.m.r. experiments show that the addition of the protic molecule(s) to the PtII and PdII complexes is reversible. The effects of the nature of the metal ion and the ancillary ligands as well as of the total charge
of the complexes on the relative stability of the addition products are discussed.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
222.
Celine Nieuwland Dr. Trevor A. Hamlin Prof. Dr. Célia Fonseca Guerra Prof. Dr. Giampaolo Barone Prof. Dr. F. Matthias Bickelhaupt 《ChemistryOpen》2022,11(2):e202100231
We have quantum chemically analyzed the influence of nucleotide composition and sequence (that is, order) on the stability of double-stranded B-DNA triplets in aqueous solution. To this end, we have investigated the structure and bonding of all 32 possible DNA duplexes with Watson–Crick base pairing, using dispersion-corrected DFT at the BLYP-D3(BJ)/TZ2P level and COSMO for simulating aqueous solvation. We find enhanced stabilities for duplexes possessing a higher GC base pair content. Our activation strain analyses unexpectedly identify the loss of stacking interactions within individual strands as a destabilizing factor in the duplex formation, in addition to the better-known effects of partial desolvation. Furthermore, we show that the sequence-dependent differences in the interaction energy for duplexes of the same overall base pair composition result from the so-called “diagonal interactions” or “cross terms”. Whether cross terms are stabilizing or destabilizing depends on the nature of the electrostatic interaction between polar functional groups in the pertinent nucleobases. 相似文献
223.
Fabio Busico Gabriella Moretti Giampaolo P. Cartoni Felice Rosati 《Journal of separation science》1992,15(2):94-98
GC-MS with negative ion chemical ionization has been used to detect anabolic estrogens (diethylstilbestrol, dienestrol, hexestrol, and 17β- and 17α-estradiol) in bovine muscle tissue. After hydrolysis and extraction, purification by column chromatography, and derivatization, the detection limit for the estrogens is better than 0.1 ppb. 相似文献
224.