无机化学学报
無機化學學報
무궤화학학보
JOURNAL OF INORGANIC CHEMISTRY
2011年
12期
2464-2472
,共9页
张辉%陈选荣%任小明%孟庆金
張輝%陳選榮%任小明%孟慶金
장휘%진선영%임소명%맹경금
Bis(maleonitriledithiolato)palladate monoanion%磁性%DFT%对称性破损
Bis(maleonitriledithiolato)palladate monoanion%磁性%DFT%對稱性破損
Bis(maleonitriledithiolato)palladate monoanion%자성%DFT%대칭성파손
bis(maleonitriledithiolato)palladate monoanion%magnetic property%density functional theory%broken-symmetry
4个一维磁链化合物[R-BzPy][Pd(mnt)2](R-BzPy+=对位取代苄基吡啶阳离子；R=Cl(化合物1),Br(化合物2),I(化合物3)和NO2(化合物4))具有相似的晶体堆积结构,即,[Pd(mnt)2]-和R-BzPy+分别形成完全分列的柱状堆积.这一结构特征与其类似化合物[R-BzPy][Ni(mnt)2]相似.但是,[Pd(mnt)2]-和[Ni(mnt)2]-2个系列化合物结构之间存在明显差异:(1)室温下,[R-BzPy][Ni(mnt)2]晶体中[Ni(mnt)2]-和R-BzPy+堆积柱是均匀的；而[R-BzPy][Pd(mnt)2]晶体中[Pd(mnt)2]-和R-BzPy+堆积柱是不均匀的.(2)在两个系列化合物阴离子堆积柱内,相邻[Pd(mnt)2]-分子平面之间距离比相邻[Ni(mnt)2]-分子平面之间距离短.在[Pd(mnt)2]-堆积柱内,[Pd(mnt)2]-离子之间反铁磁交换作用非常强,导致了化合物几乎呈抗磁性.在密度泛函理论框架下,利用对称性破损方法,我们计算了[Pd(mnt)2]-离子之间磁交换常数.在svwn/lanl2dz和bpw91/lanl2dz水平上的计算结果与磁化率拟合结果一致.理论分析揭示,在[Pd(mnt)2]-堆积柱内,[Pd(mnt)2]-离子之间强反铁磁交换与其π-型前线轨道有效重叠密切相关.
4箇一維磁鏈化閤物[R-BzPy][Pd(mnt)2](R-BzPy+=對位取代芐基吡啶暘離子；R=Cl(化閤物1),Br(化閤物2),I(化閤物3)和NO2(化閤物4))具有相似的晶體堆積結構,即,[Pd(mnt)2]-和R-BzPy+分彆形成完全分列的柱狀堆積.這一結構特徵與其類似化閤物[R-BzPy][Ni(mnt)2]相似.但是,[Pd(mnt)2]-和[Ni(mnt)2]-2箇繫列化閤物結構之間存在明顯差異:(1)室溫下,[R-BzPy][Ni(mnt)2]晶體中[Ni(mnt)2]-和R-BzPy+堆積柱是均勻的；而[R-BzPy][Pd(mnt)2]晶體中[Pd(mnt)2]-和R-BzPy+堆積柱是不均勻的.(2)在兩箇繫列化閤物陰離子堆積柱內,相鄰[Pd(mnt)2]-分子平麵之間距離比相鄰[Ni(mnt)2]-分子平麵之間距離短.在[Pd(mnt)2]-堆積柱內,[Pd(mnt)2]-離子之間反鐵磁交換作用非常彊,導緻瞭化閤物幾乎呈抗磁性.在密度汎函理論框架下,利用對稱性破損方法,我們計算瞭[Pd(mnt)2]-離子之間磁交換常數.在svwn/lanl2dz和bpw91/lanl2dz水平上的計算結果與磁化率擬閤結果一緻.理論分析揭示,在[Pd(mnt)2]-堆積柱內,[Pd(mnt)2]-離子之間彊反鐵磁交換與其π-型前線軌道有效重疊密切相關.
4개일유자련화합물[R-BzPy][Pd(mnt)2](R-BzPy+=대위취대변기필정양리자；R=Cl(화합물1),Br(화합물2),I(화합물3)화NO2(화합물4))구유상사적정체퇴적결구,즉,[Pd(mnt)2]-화R-BzPy+분별형성완전분렬적주상퇴적.저일결구특정여기유사화합물[R-BzPy][Ni(mnt)2]상사.단시,[Pd(mnt)2]-화[Ni(mnt)2]-2개계렬화합물결구지간존재명현차이:(1)실온하,[R-BzPy][Ni(mnt)2]정체중[Ni(mnt)2]-화R-BzPy+퇴적주시균균적；이[R-BzPy][Pd(mnt)2]정체중[Pd(mnt)2]-화R-BzPy+퇴적주시불균균적.(2)재량개계렬화합물음리자퇴적주내,상린[Pd(mnt)2]-분자평면지간거리비상린[Ni(mnt)2]-분자평면지간거리단.재[Pd(mnt)2]-퇴적주내,[Pd(mnt)2]-리자지간반철자교환작용비상강,도치료화합물궤호정항자성.재밀도범함이론광가하,이용대칭성파손방법,아문계산료[Pd(mnt)2]-리자지간자교환상수.재svwn/lanl2dz화bpw91/lanl2dz수평상적계산결과여자화솔의합결과일치.이론분석게시,재[Pd(mnt)2]-퇴적주내,[Pd(mnt)2]-리자지간강반철자교환여기π-형전선궤도유효중첩밀절상관.
Four quasi-one-dimensional (quasi-1D) compounds consist of bis (maleonitriledithiolato)palladate monoanions ([Pd(mnt)2]-) with benzylpyridinium derivatives (R-BzPy+,where R represents the substituent in the para-site of the phenyl ring; R=Cl,Br,I and NO2 for 1 ～4,respectively),which show similar stacking structures to the [Ni(mnt)2]- analogues.The [Pd(mnt)2]- and R-BzPy+ ions form the segregated stacks,each stack is surrounded by four counterion stacks.In comparison of [Pd(mnt)2]- with [Ni(mnt)2]- analogues,the structural distinctions involving both anion and cation stacks are regular for [Ni(mnt)2]- series; while irregular for [Pd(mnt)2]- analogues at room temperature.The inter-plane distances are shorter in [Pd(mnt)2]- than those in [Ni(mnt)2]- stack.There exist strongly antiferromagnetic (AFM) interactions in [Pd(mnt)2]- stack,which magnetic exchange constants are evaluated via broken-symmetry approach in DFT framework,and the calculated results at svwn/lanl2dz and bpw9l/lanl2dz levels are parallel to the experimental results,disclosing that the strongly AFM interactions is due to larger overlap of π-type frontier molecular orbitals.
