Gazquez and Mendez  proposed a local version of the well-known HSAB
principle, which essentially indicates that the interaction between A and B is favoured when it occurs through those atoms having approximately equal softness values.
Considering the chemical structure the more stable Cu2+ complex can be expected according to the concept of HSAB
. The presence of oxygen donors in addition to nitrogen in the macrobicyclic cavity increases the hardness properties of donor atoms.
Kabler, "A quantitative evaluation of the HSAB
concept," Inorganic Chemistry, vol.
Because small molecule FMO energies can be calculated using various quantum mechanical models, HSAB
parameters such as softness ([sigma]) and hardness ([eta]) of an electrophile are readily computed.
Keywords: Coordination polymer, Heterometallic, HSAB
, Metal-organic frameworks, Isonicotinic acid, Oxalic acid.
This feature could be explained by the Pearson's hard-soft acid-base principle (HSAB
) involved in the chelation process: borderline soft acids (such as the C[u.sup.2+], M[n.sup.2+], C[o.sup.2+], and N[i.sup.2+] ions) develop more stable coordinate complexes when binding to soft bases (such as the--SH group of the G resin) (12), (13), i.e., sulfur from the thiol group promotes a stronger chelation of the ions than the oxygen and the nitrogen found in the--N[(C[H.sub.2]COOH).sub.2] group of the IR resin.
By involving the hard soft acid base (HSAB
) principle in the local sense, one may establish the behaviour of the different sites with respect to hard or soft reagents .
According to the theory of hard and soft acids and bases (HSAB
) [26-29], the hardness order of cations investigated in our study was [Mg.sup.2+] > [Ca.sup.2+] > [Ba.sup.2+] > [Na.sup.2+] > [Na.sup.+] [greater than or equal to] N[H.sub.4.sup.+] [greater than or equal to] [K.sup.+] > [Zn.sup.2+] > [Cu.sup.2+], and [Cu.sup.2+] was the intermediate acid .