Andrew Quick

Unusual formation and crystal structure of a new stable dinuclearvanadium(V) amino–imino–acetal

Unusual formation of a new imino–amino–acetal as a dimeric complex of VO 2 + revealed dramatically how difficult it can be to form stable macrocyclic dinuclear complexes of VO 2 + and VO 2+ .

Crystal and molecular structure of parthenolide [4,5-epoxygermacra-1(10),11(13)-dien-12,6-olactone]

The crystal structure of the title compound has been determined from single-crystal X-ray data by direct methods. Crystals are orthorhombic, a= 11.929(1), b= 12.267(2), c= 18.761 (2)A, space group P212121, Z= 8. i.e. two independent molecules per asymmetric unit. Full-matrix least-squares refinement based on 2 330 independent reflections has reached R 0.047. The double bond C(1)–C(10) and the equivalent double bond C(4)–C(5) are both trans, both methyl groups are β, and the ten-membered ring has a conformation typical of several germacranolides.

Preparation, crystal structure, magnetic properties, and chemical reactions of a hexanuclear mixed valence manganese carboxylate

The antiferromagnetic mixed valence manganese complex [Mn6O2(Me3CCO2H)4(Me3CCO2)10] has been prepared by the reaction of MnCO3 with pivalic acid in toluene, and its molecular structure, determined by X-ray methods, comprises the new polynuclear cluster grouping of two tetrahedral oxygen-centred tetramanganeses clusters sharing an edge; further cluster complexes have been prepared by reaction of this complex with donor molecules.

Crystal and molecular structure of (1S,3S,5R,7S,8R,9R)-9-p-bromo-benzoyloxy-1,4,4,8-tetramethyltricyclo[5.4.0.0]undecane

The crystal structure of the title compound has been determined from single-crystal X-ray data by the heavy-atom method. Crystals are monoclinic, a= 23.165(1), b= 6.000(1), c= 14.538(1)A, β= 97° 4′, space group P21, Z= 4, i.e. 2 independent molecules per asymmetric unit. Full-matrix least-squares refinement based on 2 814 independent reflections has reached R 0.069. The molecule contains a cis-decalin system in which ring B is considerably distorted by fusion with the cyclopropane ring.

Crystallographic and spectroscopic evidence for an asymmetric proton potential in a formally symmetric system

The crystal structure of (benzimidazole2H)+ BF4– has been shown to contain a long N–N hydrogen bond [2·787(4)A] with the proton in an asymmetric single minium; this is consistent with the vibrational spectrum, which also indicates a similar potential in solution.