Biomedical subjects

Alexander B Baker

Publications and source records attributed to Alexander B Baker.

3 recordsLinked to original sources

PubMed2006

Group 4 transition-metal atom reactions with CS2 and OCS: infrared spectra and density functional calculations of SMCS, SM-(eta2-CS), SMCO, and OMCS in solid argon.

Laser-ablated titanium, zirconium, and hafnium atoms were reacted with CS2 and OCS molecules during condensation in excess argon. With CS2, the SMCS and S-M(eta2-CS) products were formed on sample deposition. Photolysis increased both complexes, while annealing favored the lower energy S-M(eta2-CS) side-bound isomer. The OCS reactions produced SMCO, OMCS, and the simple M(eta2-CO)S adduct. Product absorptions are identified by comparison with density functional theory frequency calculations and isotopic substitutions. Investigations with OCS emphasized differences in the CS and CO bond insertion products.

Journal Article↗

PubMed2006

Reactions of group 3 transition metal atoms with CS2 and OCS: Matrix isolation infrared spectra and density-functional calculations of SMCS, SM-(eta2-CS), SMCO, and SM-(eta2-CO) in solid argon.

Laser-ablated scandium, yttrium, and lanthanum atoms were reacted with CS2 and OCS molecules in an argon matrix. Products of the type SMCX and S-M(eta2-CX) (X = S or O) were formed on sample deposition. Photolysis favored the S-M(eta(2)-CX) complex, while annealing increased the more stable SMCX isomer. Product absorptions are identified by density-functional frequency calculations and isotopic substitutions. This work reports the first vibrational spectroscopic characterization of Sc, Y, and La reaction products with CS2 and OCS and the subsequent interconversion between SMCX and S-M(eta2-CX) structural isomers.

Argon↗

PubMed2005

Pentachlorocyclopropane/base complexes: matrix isolation infrared spectroscopic and density functional study of C-H- - -N hydrogen bonds.

Hydrogen-bonded complexes of pentachlorocyclopropane with the bases acetonitrile, ammonia, monomethylamine, and dimethylamine have been isolated and characterized for the first time in argon matrices at 16 K. Coordination of the proton of pentachlorocyclopropane (Pccp) to the electron donor (N) of the base was evidenced by red shifts of the CH stretching mode. These shifts, which range from 22 to 170 cm(-1), increase in the order CH3CN, NH3, (CH3)NH2, and (CH3)2NH. Density functional theory (DFT) calculations at the B3LYP level agree well with experiment and support the formation of 1:1 complexes of Pccp/base. Distinct changes were observed in ring modes as well as CCl and CCl2 modes. The hydrogen bond energy of the complexes varies from 2.95 to 4.22 kcal/mol and is stronger than our previously studied bromocyclopropane-ammonia complex (2.35 kcal/mol, MP2).

Journal Article↗