Three novel polymeric network of copper(II) constructed with succinato ligand and the influences of weak interactions on their crystal packing

 

Tian-Huey Lu,a G. Mostafaa and N. Ray Chaudhurib

 

aDepartment. of Physics, National Tsing Hua University, Taiwan, R.O.C.; bDepartment. of Inorganic Chemistry, IACS, W.B., India (thlu@phys.nthu.edu.tw)

 

 

The crystal engineering of metal organic coordination network is now a growing field. The key objective of the advanced crystal engineering is the control on manipulation of weak interactions in order to tune the properties of the bulk material to design and prepare new functional materials, such as molecular-based magnets etc. Thus, to synthesize new solid phases with predictable stoichiometry and architecture for specific applications, one has to understand the underlying factors such as hydrogen bonding, p-p, C-HÉp interactions etc. that determine crystal packing. Till date, an accurate prediction of the overall crystal structure currently is almost impossible but it may be achieved in the near future. For this reason a large database needed to obtain the crystal packing rules for a specific classes of functional material.

With this background, the carboxylate group is one of the most widely used bridging ligands for designing polynuclear complexes with interesting magentic properties. The versatility of a carboxylate group can be illustrated by the variety of bridging conformations, the most important being (a)syn-syn, (b)syn-anti and (c)anti-anti.

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       

 

Of the carboxylato groups, major studies have been done on oxalato bridged metal complexes with a few examples of terepthalate, fumarate, maleate, malonate, adipate etc but the reports on succinate and glutarate as superexchange pathways are scanty in literature. These carboxylates showed wide varieties of the superexchange phenomenon and are closely related to the bridging conformations adopted by the carboxylate group in polynuclear systems. To design a carboxylato bridged pre-assigned functional material, hence to achieve a particular bridging conformation, a systematic study and more examples of carboxylato bridged complexes are needed.

Here, we wish to report the relevance of the succinato ligand for the construction of novel network structure of Cu(II). The weak interactions, observed here to form the solid-state phases of this class of magnetic material, will be discussed. In complexes 1 and 2, a weak ferromagnetic path is observed but the global behavior is antiferromagnetic.

 

Crystal Data:

(1) [Cu2(m-OH2)2(m-succinate)(bipy)(NO3)2]n, Triclinic, P, a=7.0641(6), b=9.8410(8), c=10.4885(9) ,  α=72.079(2)0, b=73.176(2)0, γ=74.6290(10)0

(2) [Cu2(m-OH2)2(m-succinate)( phen)(NO3)2]n, Triclinic, P, a=6.9386(8), b=10.3463(14), c=10.8572(17) , α=69.734(11)0, b=81.354(11)0, γ=75.687(10)0

(3) [{Cu8(m-succinate)4(phen)12}(BF4)4]n, Triclinic, P, a=12.5769(10), b=  19.3034(15), c=19.3348(16) , α=60.187(2) 0, b=86.864(2) 0, γ=80.538(2) 0