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Your search keyword '"Haltiwanger, R. Curtis"' showing total 36 results
Start Over Author "Haltiwanger, R. Curtis" Journal inorganic chemistry
36 results on '"Haltiwanger, R. Curtis"'

1. Cleft reactivity in skeletally-stabilized cyclotetraphosphazanes

Author

Young, Susan M., Barendt, Joseph M., Carperos, Vasili, Haltiwanger, R. Curtis, Hands, Robert M., and Norman, Arlan D.

Subjects
Chemical structure -- Analysis, Oxidation-reduction reaction -- Analysis, Chemical models -- Analysis, Chemistry
Abstract

Highly regioselectivity reaction at the exo-phosphorus sites P(2,4) by cyclotetraphosphazanes forms disubstituted products. The selective reaction of the endo-P(1,3) sites in the molecular cleft of the exo-disulfide indicated that two O atoms, one S atom, Ag ion, and Ni(CO)2 moiety insert readily. The structures of cyclotetraphosphazanes were seen to be maintained on insertion into the molecular cleft of one S atom while two S atoms in the cleft causes distortion of the ring system.

Published
1995

2. Molecular cleft reactivity and conformational properties of skeletally stabilized triphosphazanes

Author

Young, Susan M., Tarassoli, Abbas, Barendt, Joseph M., Squiers, Christopher A., Barthelemy, Francoise, Schaeffer, Riley, Haltiwanger, R. Curtis, and Norman, Arlan D.

Subjects
Phosphazo compounds -- Research, Oxidation-reduction reaction -- Analysis, Chemistry
Abstract

Skeletally stabilized triphosphazanes undergo oxidation reaction with various reagents in which exophosphorus positions exhibit high regioselectivity. S(8) and O(3) react with phosphazanes to give trisubstituted products. Size-controlled molecular cleft at endo positions are responsible for the selective reactivity of the triphosphazane endo phosphorus. NMR and x-ray diffraction studies measure bond distances and angles. Orientations of P-E/P-L are compared to P-N skeleton in phosphazane.

Published
1994

3. Structural and conformational studies of diastereoselected bis(phosphino)amines

Author

Prout, Timothy R., Imiolczyk, Tomasz W., Barthelemy, Francoise, Young, Susan M., Haltiwanger, R. Curtis, and Norman, Arlan D.

Subjects
Amines -- Research, Chemistry
Abstract

Structural studies of bis(phosphino)amines RN(PXX)2 show the conformation preference around the P-N-P skeleton. NMR, electron and X-ray diffraction analyses predict three conformations for bi(phosphino)amines. 2JPNP coupling constants observed also favor the conformation around the P-N-P skeleton, even in the solid state. At low temperatures, these amines freeze into preferred conformations, but above 25 degrees Celsius they exist as an average of exchanging conformation.

Published
1994

4. Cis/Trans isomerization and conformational properties of 2,4-bis(primary amino)-1,3,2,4-diazadiphosphetidines

Author

Hill, Tara G., Haltiwanger, R. Curtis, Thompson, Martin L., Katz, Stephanie A., and Norman, Arlan D.

Subjects
Ethers -- Research, Chemistry
Abstract

Alkyl substituted 1,3,2, 4-diazadiphosphetidines are prepared from RNH2/PCl3 in a medium of petroleum ethers. Cis isomer is favored, as the bulk of the alkyl substituent is increased. The temperature dependent 3' PNMR spectra reveals that transdiazadiphosphetidines are temperature-independent up to 90 degrees Celsius. Rotational barriers around the exo P-N bands are more for cis isomers than for trans isomers.

Published
1994

5. New skeletally stabilized silazanes and siloxazanes

Author

Prout, Timothy R., Thompson, Martin L., Haltiwanger, R. Curtis, Schaeffer, Riley, and Norman, Arlan D.

Subjects
Siloxanes -- Research, X-ray crystallography -- Analysis, Chemistry
Abstract

Siladiazoles are synthesized from reactions of 1,2(NH2)6C6H4 with equimolar MePhSiCl2 and Ph2SiCl2 in the presence of Et3N. Stereoselectivity is not observed in the reactions. Spectroscopy and X-ray crystallographic studies are used to characterize silazanes and siloxazanes. Comparisons of phosphazane and silazane systems show that intergroup interactions are less and different for silazane compounds.

Published
1994

6. Synthesis and structures of volatile mononuclear and pentanuclear chelates of barium

Author

Huang, Ling, Turnipseed, Sherri B., Haltiwanger, R. Curtis, Barkley, Robert M., and Sievers, Robert E.

Subjects
Barium compounds -- Research, Chelates -- Analysis, Molecular structure -- Analysis, Chemistry
Abstract

The structures of two different Ba(II) chelates of beta-diketonates are found to be mononuclear and multinuclear. The Ba(II) chelate recrystallizes from pentane-formed monoclinic crystals. The beta-diketonate deficient pentanuclear complex is used in the analysis of the structure of the diketonates. A thermally unstable compound is produced by the bridging of water ligands and beta-diketonate complex.

Published
1994

7. Intermediates in the diastereoselective formation of bis(phosphino)amines

Author

Prout, Timothy R., Imiolczyk, Tomasz W., Haltiwanger, R. Curtis, Hill, Tara G., and Norman, Arlan D.

Subjects
Amines -- Research, Stereochemistry -- Research, Gases -- Research, Chemistry
Abstract

Meso-i-PrN(PhP(i-PrNH))2, formed from the reaction of i-PrNH2 with PhPCl2 and Et3N, was investigated for identification of intermediates. Factors such as reaction time, temperature and reactant ratios were considered to observe the function of intermediates in the diastereoselective formation of the product. The structure was analyzed on the basis of structural parameters and conformational properties.

Published
1992

8. The first coordination complexes of selenones: a structural comparison with complexes of sulfones

Author

Dikarev, Evgeny V., Becker, Renee Y., Block, Eric, Shan, Zhixing, Haltiwanger, R. Curtis, and Petrukhina, Marina A.

Subjects
Chemical bonds -- Structure, Sulfones -- Chemical properties, Sulfones -- Analysis, Chemistry
Abstract

Ligating properties of disubstituted sulfones and selenones in complexation reactions with an electrophilic complex are examined. It reveals that this direct comparison of selenium and sulfur analogues under similar experimental conditions shows similarities in their coordination but differences in thermal stability.

Published
2003

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