_tcm18-11401.gif )
The international journal for inorganic, organometallic and bioinorganic chemistry
Subscribers
Non-subscribers
- Purchase article PDF [£30 + taxes]
- Purchase article PDF member offer [£5 + taxes]
Free access
Paper
Dalton Trans., 2009, 10343 - 10352, DOI: 10.1039/b916878h
Co(II) and Cr(III) complexes of formate–formamide mixed ligands: synthesis, structures, single crystal-to-single crystal transformation and magnetic behaviour
Oindrila Sengupta, You Song and Partha Sarathi Mukherjee
Solvothermal treatment of an equimolar mixture of Co(NO3)2·6H2O, HCONH2 and NaN3 in MeOH at 100 °C yielded a three-dimensional NaCl type network Co(HCOO)2(HCONH2)2·HCONH2 ( 1a) containing formamides in the pores of the structure. Solvated pink 1a undergoes single crystal-to-single crystal (SCSC) transformation at 215 °C to form the desolvated dark brown product Co(HCOO)2(HCONH2)2 ( 1b) with the retention of the original framework. Reversible single crystal-to-single crystal transformation of 1b (brown) to 1a (pink) in the presence of excess formamide was also established at room temperature. The coordination environment around Co(II) in both 1a and 1b is octahedral with a CoN2O4 coordination composition. A similar reaction replacing Co(II) by Cr(III) produced a heterometallic 3D extended network Na[Cr(HCOO)4(HCONH2)2]·2H2O ( 2a) at 100 °C. An increase in reaction temperature to 150 °C produced a simple mononuclear complex Cr(HCOO)3(HCONH2)3·3H2O ( 2b). Variable temperature magnetic studies revealed the presence of a canting phenomena in both 1a and 1b, and hysteresis loop in the field dependent magnetisation plot at 2 K whereas complex 2a is simply paramagnetic in nature.
RSS feed