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Metal−organic framework (MOF) materials show potential for gas separation and storage, and as hosts for highly selective catalyst molecules. Density functional theory (DFT) is applied to periodic band structures and to selected clusters representative of the cornerpost and strut environments of two MOFs to characterize the electronic environment. Binding sites and the binding energies of H 2are calculated with and without the presence of a Li dopant. It is found that Li enhances the H 2binding energies, both on the linking strut ring structures and for sites near cornerpost oxygen. MP2 correlation studies of the basic H 2−Li−bipyridine interaction are carried out to explore effects of correlation beyond DFT. Contrary to previous model assumptions, we find that Li associates strongly with the cornerposts and less so with aromatic rings.

A recently developed class of molecular squares based on octahedral ReCl(CO)3R2 cornerposts has until now lacked a detailed theoretical description. We present an analysis of electronic structure of five of the simplest squares, rectangles, and related fragments; that is, those with pyrazine and bipyridine walls. We further consider a square containing Zn−porphyrin walls. The derived electronic charge distributions reveal bonding structure and spectral features of the class. We show that the analysis of conformational preferences can be greatly simplified by using a “piecewise” strategy, which enables us to make several generic statements about conformations of this class of macromolecules. To further illustrate advantages of this approach, we find the origin of metastability of the planar conformation of the bipyridine square.

Nony Ardill and Nigel Cross, Undocumented Lives: Britain's Unauthorised Migrant Workers London: Runnymede Trust, 1988, 105 pp., £2.95 p.b.Peter A. Roberts, West Indians and their Language Cambridge: Cambridge University Press, 1988, 215 pp., £8.95 p.b.Alison Shaw, A Pakistani Community in Britain Oxford: Basil Blackwell, 1988, 187 pp., £19.50 h.b.Clive Y. Thomas, The Poor and The Powerless: Economic Policy and Change in the Caribbean London: Latin American Bureau, 1988, 396 pp., £29.95 cloth, £8.95 p.b.Institute of Personnel Management, Contract Compliance: The U.K. Experience London: IPM, 1987, 100 pp., n.p.Caroline Adams, Across Seven Seas and Thirteen Rivers: Life Stories of Pioneer Sylhetti Settlers in Britain London: THAP Books, 1987, 248 pp., £9.95 cloth, £4.95 p.bFazlul Alam, Salience of Homeland: Societal Polarization within the Bangladeshi Population in Britain (Research Papers in Ethnic Relations No. 7) University of Warwick: Centre for Research in Ethnic Relations, 1988, 70 pp., £4.00 p.b.Margaret A. Gibson, Accommodation without Assimilation: Sikh Immigrants in an American High School Ithaca, New York: Cornell University Press, 1988, 244 pp., $34.95 cloth, $12.95 p.b.Malcolm Cross & Han Entzinger, Lost Illusions: Caribbean Minorities in Britain and the Netherlands London: Routledge, 1988, 316 pp., n.p.Young Yun Kim, Communication and Cross-Cultural Adaption Clevedon: Multilingual Matters, 1988, 223 pp., £22.95 h.b., £7.95 p.b.Brian D. Jacobs, Racism in Britain London: Christopher Helm, 208 pp., £14.95 h.b., £6.95 p.b.Samuel Abudarham (ed), Bilingualism and the Bilingual Windsor: NFER-Nelson, 1987, 199 pp., n.p.Finbarre Fitzpatrick, The Open Door Clevedon: Multilingual Matters 26, 1987, vii + 126 pp., £17.00 h.b., £6.95 p.b.Bernard Spolsky (ed), Language and Education in Multilingual Settings Clevedon: Multilingual Matters 25, 1986, vii + 200 pp., £23.00 h.b., £9.90 p.b.Suman Fernando, Race and Culture in Psychiatry London: Routledge, 1988, xviii+216 pp., £25 h.b.Peter Fryer, Black People in the British Empire: an Introduction London: Pluto Press, 1988, 174 pp., £14.95 h.b.Alan Paton, Journey Continued: an Autobiography Oxford: Oxford University Press, 1988, 308 pp., £14.95 p.b.Ethelbert W. Haskins, The Crisis in Afro-American Leadership Buffalo, New York: Prometheus Books, 1988, 196 pp., £14.95 clothSimon Jones, Black Youth, White Culture: The Reggae Tradition from JA to UK Basingstoke: Macmillan, 1988, 251 pp., £33 h.b., £9.50 p.b.Robin Cohen, The New Helots: Migrants in the International Division of Labour Aldershot: Avebury, 1987, 290 pp., £8.95 p.b., £27.50 h.b.

Hexacarbonyltitanate(2-) reacts with (R3P)AuCl (R = C6H11, Et) to provide the first anions of the general formula [M(CO)x(AuPR3)y] z, and a structurally characterized (for R = Et) compound containing a largely unsupported gold–titanium bond.