Effect on Structure and Properties

Ionization potentials of dispiro[2,2,2,2]deca-4,9-diene (531) have been measured, providing information about the conjugation of the cyclopropane Walsh orbitals with the diene orbitals. 

The effects of methoxy and hydroxy substituents on phenonium ions (780) generated in strong acids have been examined. Methoxy-groups in the wieta-positions destabilize the phenonium ion, whereas it is stabilized by ortho- and para-methoxy-groups, according to n.m.r. evidence. Interestingly, solutions of such ions in strong acids show weak 

Haddon has examined theoretically the question of conjugation in the cations (781 n = 1 or 2) and concludes that the homotropylium cation (781 n = 1, m = 3) 

Nakato, T. Chiyoda, and H. Tsubomura, Bull. Chem. Soc. Japan, 1974,47, 3001 H. Harada, K. Ohno, 

Conformational analysis of cyclopropylbenzenes reveals that the most important interactions occur in the bisected conformation, with the three-membered ring behaving as an electron donor towards unsaturated substituents on the aromatic ring.  

A study of the hydrogen bond strength in the monoanion of cyclopropane-1,1-dicarboxylic acid has reaffirmed the view that this bond strength is not necessarily related to the angle between the two acid functions. The influence of a cyclopropyl group attached to the chiral centre of an optically active molecule on the optical rotation has been shown to be greater than that of a methyl group but lower than that of a pentyl function.  

The application of CNDO/2, MINDO/3, and SPINDO methods to spirocon-jugated molecules including (349) and the as yet unknown (350) indicates that ionization of the latter should be most easily achieved. It should be added that the MINDO/3 calculations do not replicate the known ic LUMO splittings particularly 

The rate of hydroboration of a series of 1,1-disubstituted ethylenes by 9-bora-bicyclo[3,3,l]nonane is enhanced by a 1-cyclopropyl substituent, but retarded by a 

Takeuchi, K. Komatsu, K. Yasuda, and K. Okamoto, Tetrahedron Letters, 1976, 3467. 

1-aryl substituent. The influence of the three-membered ring is such that it largely overcomes the deactivating influence of an aryl group in 1-aryl-l-cyclopropyl-ethylenes. Cyclopropyl substituent effects on the A-S 2 acid-catalysed hydration of alkenes have also been studied.  

Three-membered Rings Neighbonrii Groups.—Effect on Structure and Properties. 

The photoelectron spectral data of (383) correlate with the results of a MINDO/2 treatment, and the spectroscopic evidence unequivocally establishes that the Walsh orbitals of a cyclopropyl group and the Jt-orbital of a neighbouring double bond interact strongly when the vinylcyclopropane is syn- or anti-periplanar. There is no 

spectra of 1-alkylcyclopropyl methyl ketones exhibit a cyclopropyl- 7t band which is ascribed to rotation of the carbonyl group fi om the bisected conformation with a subsequent stabilization of the 7c -orbital. The observed n- n hypsochromic shift results from destabilization of the jc -orbital. Ketone (385) has an unusually high dipole moment (3.67 D) because of significant cyclopropane-carbonyl interaction.  

Klessinger, L.-U. Meyer, and A. de Meijere, Tetrahedron Letters, 197S, 381. 

The influence of a cyclopropane ring on an adjacent cationic centre continues to be examined. The cations derived from 4-substituted bicyclo[3,l,0]hex-2-enes and their benzo analogues (359) exist, under stable ion conditions, as cyclopentyl-like cations with charge delocalization into the three-membered ring, but with no homoantiaromatic or Mobius-type character. Dibenzotropylium ion (384 = cyclopropyl = H) and the dibenzocycloheptadiene counterpart both show considerable 

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BLOCK AND GRAFT COPOLYMERIZATION 11.10.1 Effects on Structure and Properties of Polymers... 

Li, Y., and Hardin, I. R. (1999). Enzymatic scouring of cotton Effects on structure and properties. Text Chem. Colorists, 29(8), 71-76. 

Morrison, N. J., Porter, M. (1983). Temperature effects on structure and properties during vulcanization and service of sulfur-crosslinked rubbers, Plast. Rubber Proc. 

Brinkmann, T., Hock, P., and Michaeli, W., The viscosity ratio during the mixing of polymer blends composed of liquid crystalline and conventional thermoplastics with regard to its effect on structure and properties, SPE ANTEC 37 988 (1991). 

Ruan W H, Rong M Z and Zhang M Q (2007) Drawing-induced dispersion of nanopai--ticles and its effect on structure and properties of thermoplastic nanocoiiiposites, Key Eng Mater 334-335 717-720. 

Effect of Alkoxysilane on Structure and Properties of Rubber-Sihca... 

EFFECT OF ALKOXYSILANE ON STRUCTURE AND PROPERTIES OF RUBBER-SILICA HYBRID NANOCOMPOSITES... 

Jansen, M. (1987) Homoatomic dlO-dlO Interactions Their Effects on Structure and Chemical and Physical Properties. Angewandte Chemie International Edition, 26, 1098-1110. 

In this work we present a description of the quantification of structural effects on reactivities and properties of polyene systems. 

This keynote paper gives a general discussion of blast waves developed by high explosive detonations, their effects on structures and people, and risk assessment methods. The properties of free-field waves and normally and obliquely reflected waves are reviewed. Diffraction around block shapes and slender obstacles is covered next. Blast and gas pressures from explosions within vented structures are sumnarized. 

Structural effects on reactivity and properties of oximes and hydroxamic acids... 

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