0000000000054021
AUTHOR
Henri Handel
showing 4 related works from this author
Electrochemically-driven conformational shift in mono- and di-copper constrained macrotricyclic cyclen receptors
2008
International audience; An electrochemical study of mono- and di-copper constrained cyclen macrotricycles is presented. Electrochemical data in DMF solution indicate that the reduction of dinuclear complexes occurs in two steps in the -0.4 to -0.8 V vs.AgCl/Ag potential range yielding CuII CuI and CuI CuI species further reduced to Cu metal at highly negative potentials. Mononuclear complexes are reduced in two steps to CuI and Cu metal. Electrochemical data suggest that reduction of both mononuclear and dinuclear complexes approach a square scheme involving electrochemically-driven conformational shifts for metal ions. The presence of endo- and exo-forms of the complexes are revealed by ch…
Macrocycle-Based Spin-Crossover Materials
2009
International audience; New iron(II) complexes of formula [Fe(L1)](BF(4))(2) (1) and [Fe(L2)](BF(4))(2) x H(2)O (2) (L1 = 1,7-bis(2'-pyridylmethyl)-1,4,7,10-tetraazacyclododecane; L2 = 1,8-bis(2'-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane) have been synthesized and characterized by infrared spectroscopy, variable-temperature single-crystal X-ray diffraction, and variable-temperature magnetic susceptibility measurements. The crystal structure determinations of 1 and 2 reveal in both cases discrete iron(II) monomeric structures in which the two functionalized tetraazamacrocycles (L1 and L2) act as hexadentate ligands; the iron(II) ions are coordinated with six nitrogen atoms: four from …
Guidelines to design new spin crossover materials
2010
International audience; This review focuses on new families of spin crossover (SCO) complexes based on polynitrile anions as new anionic ligands or on polyazamacrocycles as neutral macrocyclic ligands. We have shown that the structural and electronic characteristics (original coordination modes and high electronic delocalization) of the polynitrile anions can be tuned by slight chemical modifications such as substitution of functional groups or variation of the negative charge to design new discrete or polymeric SCO systems.In our ongoing work on the design of new molecular systems based on new ligands that can be fine-tuned via chemical modifications, another promising way which has been r…
Modes of complexation of non-substituted and substituted tetraazamacrocycles with Group 6 metal carbonyls. X-ray structure of [(permethylcyclam)Mo(CO…
1995
Abstract Reactions of complexation of tetraazamacrocycles L with Group 6 metal carbonyls [M(CO)6](M = Cr, Mo, or W) lead to [LM(CO)4], [LM(CO)3] or [LM(CO)2] entities, depending both on the size of the macrocycle and on the metal M. The structure of one representative complex [(permethylcyclam)Mo(CO)4] has been determined by X-ray diffraction (permethylcyclam: 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane).