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RESEARCH PRODUCT

Supramolecular diversity and magnetic properties of novel heterometallic Cu(II)/Cr(III) complexes prepared from copper powder, Reineckes salt and ethylenediamine

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Abstract Three novel heterometallic complexes [Cu(en) 2 Cr(NCS) 4 (NH 3 ) 2 ][Cr(NCS) 4 (NH 3 ) 2 ] · 6dmf ( 1 ), [Cu(en) 2 Cr(NCS) 4 (NH 3 ) 2 ](OAc) ( 2 ) and [{Cu(en) 2 } 3 {Cr(NCS) 4 (NH 3 ) 2 } 2 (NCS) 2 ](NCS) 2 ( 3 ) have been synthesized in a one-pot reaction from copper powder, Reineckes salt, NH 4 X [X −  = OAc − ( 2 ), NCS − ( 3 )] in a dmf ( 1 ) or CH 3 CN ( 2 , 3 ) solution of ethylenediamine (en). X-ray studies showed that 1 and 2 consist of cationic polymeric chains, formed by Cu ( en ) 2 2 + and Cr ( NCS ) 4 ( NH 3 ) 2 - building blocks that bridged through thiocyanate anions. In both complexes, distinct hydrogen bonds are present and serve to increase the dimensionality of the compound from one to two (in 1 ) or three (in 2 ). The main structural feature of 3 is the pentanuclear Cu 3 Cr 2 cation which is H-bonded with uncoordinated thiocyanate groups generating a 3D supramolecular assembly. The shortest Cu⋯Cr distances are 5.840(1) A for 1 , 5.856(1) and 6.018(3) A for 2 and 6.009(9) and 6.465(9) A for 3 . Compounds 1 and 2 are essentially paramagnets whereas compound 3 shows a weak antiferromagnetic coupling. The magnetic properties are simulated and discussed in terms of the structural features.