title: Configurations of metallocyclams and relevance to anti-HIV activity.
abstract: Antiviral cyclam macrocycles block viral entry into cells by binding to the CXCR4 co-receptor. Cyclams bind transition metal ions strongly and can potentially form a range of trans (I-V) and cis configurations which may be recognised differently by co-receptor proteins. A survey of the CSD (crystallographic structural database) shows that the trans-III configuration is the most common in the solid state for complexes of cyclam itself. Other configurations can be induced by N-substitution or ternary complexation and by interaction with solvents in solution. We report X-ray structures for the square-planar trans-III complexes [Pd(cyclam)]Cl(2).2MeOH and the C-C linked dimer [Pd(2)(2,2'-bi-(1,4,8,11-tetraazacyclotetradecane))](ClO4)(4), in which the planes of the two cyclam rings are close to perpendicular (100.1 degrees ), and for tetra-N-benzyl-cyclam and its 5-coordinate Ni(II) complex [Ni(Bz(4)-cyclam)Cl]Cl which has the unusual trans-I configuration.
authors.affiliation: School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, Scotland, UK.
authors.forename: Tina M
authors.initials: TM
authors.lastname: Hunter
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Paisey
authors.forename: Hye-seo
authors.initials: HS
authors.lastname: Park
authors.forename: Laura
authors.initials: L
authors.lastname: Cleghorn
authors.forename: Andrew
authors.initials: A
authors.lastname: Parkin
authors.forename: Simon
authors.initials: S
authors.lastname: Parsons
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Sadler
mesh_terms: D019380:Anti-HIV Agents / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D018360:Crystallography, X-Ray; D006801:Humans; D066298:In Vitro Techniques; D047029:Lactams, Macrocyclic / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D019718:Receptors, CXCR4 / Q000187:drug effects; D013237:Stereoisomerism
chemical_list: D019380:Anti-HIV Agents; D047029:Lactams, Macrocyclic; D008024:Ligands; D009942:Organometallic Compounds; D019718:Receptors, CXCR4