From RWOODS@VAX.MOLECULAR-BIOPHYSICS.OXFORD.AC.UK Mon Jan 18 18:57:00 1993 Message-Id: <199301181855.AA29622@oscsunb.ccl.net> Date: Mon, 18 Jan 93 18:57 GMT From: RWOODS%VAX.MOLECULAR-BIOPHYSICS.OXFORD.AC.UK@OHSTVMA.ACS.OHIO-STATE.EDU To: CHEMISTRY@ccl.net Subject: Anomeric Effect Dear Netters: Are there definitive or at least generally accepted values for the energies of the anomeric and exo-anomeric effects? I am looking for references for both experimental and computational values. Thanks in advance, Rob Woods Robert J. Woods, Ph.D. Glycobiology Institute Department of Biochemistry University of Oxford South Parks Road Oxford, OX1 3QU From PODOSNNA@NYUACF1.bitnet Mon Jan 18 10:16:00 1993 Message-Id: <199301181916.AA29879@oscsunb.ccl.net> Date: Mon, 18 Jan 93 14:16 EDT From: Subject: conformational space search To: chemistry@ccl.net Dear netters, Does anyone know anything about the software package that can generate conformerr not only by dihedral angle driving but also by bond angles and bond lengths distortions? Besides, is there any traditional ('cause I'm a novice here) algorythm to search N-dimensional conformational space. Thanks in advance for all help. Andrew Podosenin PODOSNNA@ACFCLUSTER.NYU.EDU From dmschn@bb1t.monsanto.com Mon Jan 18 09:27:22 1993 Date: Mon, 18 Jan 93 15:27:22 -0600 Message-Id: <9301182127.AA15271@tin.monsanto.com> From: dmschn@bb1t.monsanto.com To: "chemistry@ccl.net"@tin.monsanto.com Subject: next Molecular Graphics Society Meeting Does anyone have registration information about the next Molecular Graphics Society Meeting in the UK in March? Thanks, Dora Schnur dmschn@bb1t.monsanto.com From harbowy@chemres.tn.cornell.edu Mon Jan 18 11:40:42 1993 Message-Id: <199301182142.AA01716@oscsunb.ccl.net> From: m.e. Subject: UHF calc's on diradicals/TS To: CHEMISTRY@ccl.net (computational chemists) Date: Mon, 18 Jan 93 16:40:42 EST Organization: Cornell Chem Grad Student In the continuing saga of my study of the Bergman cyclization: J. Stewart had suggested use of UHF calculations rather than CI for modelling the closure of a simple enediyne to benzene diradical. Using the AM1 hamiltonian, the results were 120.08 kcal for the enediyne, with a s**2 of 0.000013, 159.77 kcal for the TS with a S**2 of 1.359032, and 122.60 for the biradical with a s**2 of 1.576831. CI had done a terrible job of finding the TS because all the minimization techniques (NLLSQ, TS, SIGMA) failed to work for a variety of reasons, including running too slow (up to two weeks of dedicated RS/6000-530 computer time without locating a TS) or a failure of the line-minimizer or 'finding no lower heat of formation' thus giving a gradient of no less than 10. The UHF calc'ns converged rapidly but as one can see, the results for the TS and biradical are heavily contaminated with the triplet state, which should render the calculation effectively useless (so I believe.) Are there any further suggestions? Are the UHF calculations in fact, garbage? -- matt ----------------------------------------------------------------------------- |/ _ /\ Matthew Harbowy (ikf@lithium.tn.cornell.edu) |\ - /__\ "I'm the bear that went over the mountain" ----------------------------------------------------------------------------- What kind of rule Can overthrow a fool and leave the land with no stain? -Suzanne Vega