0000000000857744
AUTHOR
Angel Gutiérrez
TCNQ radical salts containing magnetic complexes: Different interaction modes of TCNQ with Copper tetraazamacrocycles
Abstract This work is devoted to the study of compounds [M(N 4 )](TCNQ) n , where N 4 = saturated or unsaturated tetraazamacrocycles, TCNQ= 7,7,8,8-tetracyanoquinodimethane, n= 2, 3. The metal is coordinated to two TCNQ groups only when there is coordinative unsaturation on it. When n= 2 all the TCNQ units are radical anions and no charge delocalization is observed. In the compounds with n= 3 only 2 3 of the TCNQ are negatively charged and a greater charge delocalization is possible. This delocalization only appears when none of the TCNQ's are coordinated to the metal and it is reflected in the higher conductivity values obtained in the solid state.
Strategies exhibited by good and average solvers of geometric pattern problems as source of traits of mathematical giftedness in grades 4-6
International audience; We describe and analyse the strategies used by students in primary grades 4, 5 and 6 to solve linear and affine geometric pattern problems. Based on two problems posed in a teaching experiment, we have identified several profiles of strategies used by students to solve the problems. We consider the profiles of students who were good geometric pattern problem solvers as traits that may help identify mathematical giftedness. Our results show that average students used very often incorrect functional strategies and were consistent in using incorrect proportional strategies along the grades. On the other hand, good geometric pattern problem solvers tended to use correct …