A comprehensive study of the unimolecular dissociation of the N(3) radical on the ground doublet and excited quartet potential energy surfaces has been carried out with multireference single and double excitation configuration interaction and second-order multireference perturbation methods. Two forms of the N(3) radical have been located in the linear and cyclic region of the lowest doublet po...

(Aminoferrocenyl)(ferrocenyl)carbene(pentacarbonyl)tungsten(0) (CO)5W=C(NHFc)Fc (W(CO) 5 ( E -2)) is synthesized by nucleophilic substitution of the ethoxy group of (CO)5W=C(OEt)Fc (M(CO) 5 (1 (Et) )) by ferrocenyl amide Fc-NH(-) (Fc = ferrocenyl). W(CO) 5 ( E -2) thermally and photochemically eliminates bulky E-1,2-diferrocenylimine ( E -3) via a formal 1,2-H shift from the N to the carbene C ...

The Weighted Histogram Analysis Method (WHAM), an extension of Ferrenberg and Swendsen’s Multiple Histogram Technique, has been applied for the first time on complex biomolecular Hamiltonians. The method is presented here as an extension of the Umbrella Sampling method for free-energy and Potential of Mean Force calculations. This algorithm possesses the following advantages over methods that a...

Impact of saturation of the sugar C(3’)=C(4’) bond of acytidine nucleoside derivative, 3’, 4’-didehydro-3’-deoxycytidine (I) is revealed usingsimulated vibrational spectra, with respect to 3’-deoxycytidine. The density functional theory based calculations found that the C(3’)=C(4’) double bondrestricts the sugar flexibility and affects the sugar-base intramolecular hydrogen bond network. For 3’...

Conformational energies for inulobiose [beta-D-fructofuranosyl-(2----1)-beta-D-fructofuranoside], a model for inulin, were computed with the molecular mechanics program MMP2(85). The torsion angles of the three linkage bonds were driven in 20 degree increments, and the steric energy of all other parameters was minimized. The linkage torsion angles defined by C-1'-C-2'-O-C-1 (phi) and O-C-1-C-2-...

The title compound, 5-amino-8-(2,3,5-tri-O-benzoyl-β-D-ribofuranosyl)pyrimido[4,5-d]pyrimidine-2,4(3H,8H)-dione methanol monosolvate, C(32)H(25)N(5)O(9)·CH(4)O, which crystallized slowly from methanol, exhibits an anti conformation with a glycosyl-bond torsion angle of χ=-141.28 (17)°. The furanose moiety adopts an N-type sugar puckering ((3)T(4)). The corresponding pseudorotation phase angle a...

The synthesis of optically active sulfinic acid esters has been accomplished by the acid catalyzed alcoholysis of optically active sulfinamides. Sulfinates are formed in this reaction with a full or predominant inversion of configuration at chiral sulfur or with predominant retention of configuration. The steric course of the reaction depends mainly on the size of the dialkylamido group in the ...