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Flexible cis-Cyclohexane-1,4-diammonium Ion in Magnetic [Ni(dmit)2] Crystals.

Authors :: Ye, Qiong
Shi, Ping-Ping
Chen, Zi-Qi
Akutagawa, Tomoyuki
Noro, Shin-ichiro
Nakamura, Takayoshi
Source :: European Journal of Inorganic Chemistry; Aug2012, Vol. 2012 Issue 23, p3732-3739, 8p
Publication Year :: 2012
Abstract: Reactions exchanging the cation in ( nBu<subscript>4</subscript>N)[Ni(dmit)<subscript>2</subscript>] to cis-cyclohexane-1,4-diammonium ( cis-CHDA) in the presence of [18]crown-6, benzo[18]crown-6 (B[18]crown-6) and dibenzo[18]crown-6 (DB[18]crown-6) yielded crystals of the monovalent [Ni(dmit)<subscript>2</subscript>] complex, namely ( cis-CHDA)([18]crown-6)<subscript>2</subscript>[Ni(dmit)<subscript>2</subscript>]<subscript>2</subscript> ( 1), ( cis-CHDA)(B[18]crown-6)<subscript>2</subscript>[Ni(dmit)<subscript>2</subscript>]<subscript>2</subscript> ( 2) and ( cis-CHDA)(DB[18]crown-6)<subscript>2</subscript>[Ni(dmit)<subscript>2</subscript>]<subscript>2</subscript> ( 3). The two ammonium groups (-NH<subscript>3</subscript><superscript>+</superscript>) of the cis-CHDA dication at axial and equatorial positions interact with oxygen atoms of the corresponding upper and lower crown ethers to form sandwich-type supramolecular cationic structures. The lateral [Ni(dmit)<subscript>2</subscript>]<superscript>−</superscript> anion arrangements through S-S contacts along the short and long axis of [Ni(dmit)<subscript>2</subscript>] anions were realised in crystals of 1, 2, and 3 by the asymmetrical cis-CHDA dication. The temperature- and frequency-dependent anisotropic dielectric constants of a crystal of 1 were evaluated along the a, b and c axes, where the thermally activated motion of the structurally flexible cis-CHDA dication was consistent with the dielectric responses. [ABSTRACT FROM AUTHOR]