Stability constants, enthalpies, and entropies for metal ion-lariat ether interactions in methanol solution

New functionalised C,C-bipyrazoles. Synthesis and cation binding properties

“…We notice for all transition metals under study that the extraction yield is practically the same for 4 with a side-arm bearing a functionalised donor-group and 6 without a donorgroup in a side-arm. Indeed, we can conclude here, contrary to the literature, [19][20][21][22] that the complexation was due to the bipyrazole nitrogens without contribution of a side arm.…”

“…It has been found that a donor atom in a side chain of lariat ethers increases the binding ability of the macrocycle. [19][20][21] Furthermore, structures with side arms attached at a nitrogen (N-pivot lariat ethers) instead of a carbon (C-pivot lariat ethers) have stronger binding properties because of greater flexibility, allowing the donor site to have the best binding position. 22…”

Pyrazolic tripods synthesis and cation binding properties

“…Contrary to the literature in which a donor atom in a side chain of a lariat ethers increases the binding ability of the macrocycle, [7][8][9] the comparison between 3 with a donor atom in a side chain and 2 without a donor atom shows that there is practically no change in the percentage of complexation. Indeed, we can conclude here that the complexation was due to the tripod nitrogens without contribution of a side arm.…”

“…It has been found that a donor atom in a side chain of lariat ethers increases the binding ability of the macrocycle. [7][8][9] Furthermore, structures with side arms attached at a nitrogen (N-pivot lariat ethers) instead of a carbon (C-pivot lariat ethers) have stronger binding properties because of greater flexibility, allowing the donor site to have the best binding position. 10…”

DFT study of the carbon‐ and nitrogen‐pivot lariat crown ethers and their complexes with alkali metal cations: Na+, K+

“…(c) With respect to C and D , the values of $ \Delta E $ are almost equal, it shows their near electron‐donating ability and reactivity. So just as the conclusions in literature44: “lengthening the pendant arms (and by including an additional donor atom on the 18‐crown‐6 compounds) has little effect on the log K n value.” Lengthening the sidearm and including more donor atoms in it have little effect on the binding ability of the LCEs to alkali‐metal cations. (d) Double‐armed N‐pivot LCE E has the largest value of E HOMO and the lowest value of $ \Delta E $ .…”