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7. INVESTIGATION OF THE SYNTHESIS AND TESTING OF VARIOUS POSSIBLE BORON- ORGANO AND OTHER SIMILAR POLYMERS

Author

WASHINGTON UNIV ST LOUIS MO SCHOOL OF ENGINEERING AND APPLIED SCIENCE, STOUT, L. E., CHAMBERLAIN, D. F., WASHINGTON UNIV ST LOUIS MO SCHOOL OF ENGINEERING AND APPLIED SCIENCE, STOUT, L. E., and CHAMBERLAIN, D. F.

Abstract

Efforts were directed toward the synthesis of compounds of the types Rsub2Ti(OH)sub2 and RB(OH)sub2,where R is the organic radical. Experiments verified literature findings that organo-Ti compounds containing a Ti-C bond could not be formed. Of the alkyl- and arylboronic acid possibilities, only the Pr, Bu, hexyl, and Ph derivatives were isolated. These compounds were heat and moisture sensitive; no conditions of temperature, concentration, time, atmosphere, or catalyst were found which would induce condensation polymerization to Boron Polymeric Organo complexes of BFsub3 and Hsub3BOsub2Fsub2 were formed. Heating the complexes produced various reactions, primarily decomposition, but did not cause polymerization. Condensation polymers were obtained from Hsub3BOsub3 and several glycols, but they were low melting and Hsub2O soluble. Low-melting, Hsub2O-sensitive polymers were also formed from mixtures of glycerol, Hsub3BOsub3, and phthalic or maleic anhydride or fumaric acid. The boronic acids were not similar to dihydroxy-silicones which undergo condensation polymerization; they decomposed to Hsub3BOsub3 or the anhydride. When B-containing polymeric esters or amides were formed, the presence of B produced Hsub2O sensitivity.

Published
1952

9. Atlas of the Bryophytes of Britain and Ireland (Book).

Author

Chamberlain, D. F.

Subjects
*BRYOPHYTES, *NONFICTION
Abstract

Reviews the book "Atlas of the Bryophytes of Britain and Ireland," vol.1, "Liverworts," edited by M.O. Hill, C.D. Preston and A.J.E. Smith.

Published
1991

10. Hybridization among sympatric species of Rhododendron (Ericaceae) in Turkey: morphological and molecular evidence.

Author

Milne RI, Abbott RJ, Wolff K, and Chamberlain DF

Abstract

Rhododendron (Ericaceae) is a large genus in which barriers to hybridization are especially weak, but many species are maintained in sympatry. Hybridization among four species of Rhododendron subsect. Pontica, which occur in sympatry in Turkey, was investigated. Material of R. ponticum, R. smirnovii, R. ungernii, and R. caucasicum and their putative hybrids was collected from the wild. Based on morphology, chloroplast DNA and nuclear ribosomal DNA restriction fragment length polymorphism (RFLP) profiles, each accession was identified as a species or hybrid combination. Five of the six possible hybrid combinations among the four species were detected. Rhododendron ponticum × R. smirnovii was represented by a single individual and R. caucasicum × R. smirnovii by one small group of hybrid plants. The combinations R. ponticum × R. ungernii and R. ungernii × R. smirnovii showed evidence of frequent backcrossing, while R. ponticum × R. caucasicum appeared unusual in that an intermediate hybrid type was abundant, whereas hybrids with phenotypes approaching either parent were rare. Possible explanations of this latter situation are discussed. The results suggest that natural hybridization among Rhododendron species is common and that ecological factors are important in maintaining integrity when species occur in sympatry.

Published
1999

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