CAJ | 학술논문

合成并表征了一种新的离子对化合物[14-NH_2-Py][TCNQ](其中4-NH_2-Py+是4-氨基吡啶阳离子,TCNQ-为7,7,8,8-四氰基对苯二醌二甲烷自由基阴离子).在该离子对化合物晶体中,2个TCNQ-离子形成了面对面堆积的二聚体;阴离子中的氰基分别和阳离子上的氨基、吡啶质子化氮原子之间存在非常强的分子间氢键.通过氢键作用,相邻的TCNQ-二聚体被阳离子连成三维氢键网络.变温磁化率测量表明,在2～400 K温度范围内,该离子对化合物表现为抗磁性.在密度泛函理论框架下,用对称性破损方法计算了化合物晶体中二二聚体内以及通过氢键连接的相邻的TCNQ-离子之间的磁交换常数,发现π二聚体内存在非常强的反铁磁交换作用,与之相比,通过氢键连接的TCNQ-离子之间的磁交换作用可以忽略.π二聚体内强反铁磁交换作用(J/k_B=1805 K)导致了该化合物基本表现为抗磁性.
합성병표정료일충신적리자대화합물[14-NH_2-Py][TCNQ](기중4-NH_2-Py+시4-안기필정양리자,TCNQ-위7,7,8,8-사청기대분이곤이갑완자유기음리자).재해리자대화합물정체중,2개TCNQ-리자형성료면대면퇴적적이취체;음리자중적청기분별화양리자상적안기、필정질자화담원자지간존재비상강적분자간경건.통과경건작용,상린적TCNQ-이취체피양리자련성삼유경건망락.변온자화솔측량표명,재2～400 K온도범위내,해리자대화합물표현위항자성.재밀도범함이론광가하,용대칭성파손방법계산료화합물정체중이이취체내이급통과경건련접적상린적TCNQ-리자지간적자교환상수,발현π이취체내존재비상강적반철자교환작용,여지상비,통과경건련접적TCNQ-리자지간적자교환작용가이홀략.π이취체내강반철자교환작용(J/k_B=1805 K)도치료해화합물기본표현위항자성.
An ion-pair type of hydrogen bonding molecular magnetic compound was prepared by means of combining the paramagnetic TCNQ-(TCNQ=7,7,8,8-tetracyanoquinodimethane) and nonmagnetic 4-aminopyridinium. The single crystal structure of the title compound shows two TCNQ-anions form an isolatedtype(TCNQ)22-dimer, and the adjacent (TCNQ)22-dimers are connected by 4-aminopyridinium via strong hydrogen-bonding. The variable temperature magnetic susceptibility measurement in the temperature range of 2~400 K indicates diamagnetism characteristics of the compound. The magnetic coupling constants between the neighboring TCNQ-anions were evaluated by the broken-symmetry approach in the density functional theory (DFT) framework. The results reveal that the strong antiferromagnetic coupling interaction (J/k_B=1805 K) within the π-type (TCNQ)22- dimer gives rise to the diamagnetism behavior for this ion-pair compound.