Two unusual mixed-valent trinuclear CuII2CuI complexes containing copper(i) tribromide dianion as bridging ligand: Identification of an unprecedented doubly hydrogen-bonded water dimer

Amidothiourea based colorimetric receptors for basic anions: evidence of anion induced deprotonation of amide –NH proton and hydroxide induced anion⋯π interaction with the deprotonated receptors

“…The hydrogen bond parameters (the O … O separation, 3.040(7) Å, H(1W) … O distance, 2.63 Å and ,O-H(1W) … O is 107) of this dimer also are in good agreement with the previously reported theoretically calculated hydrogen-bonded water dimer by different density functional theory (Table 3). 19 In this regard, similar doubly hydrogen-bonded water dimer in the mixed valence copper complex recently reported by Ghosh and coworker, 20 but to best of our knowledge, until now identification of a doubly hydrogen-bonded water dimer in a metal free hydrophobic system is still unprecedented.…”

Steric Effect of a Capping Ligand on the Formation of Supramolecular Coordination Networks of Ni(II): Solid-State Entrapment of Cyclic Water Dimer

“…These two lattice water molecules form a doubly hydrogen-bonded cyclic water dimer, which acts as a bridge between two bis(adc)Ni 2 (II) units, as shown in Figure 2. These two water molecules O5 and O5′ in 1 show doubly 33 but the water dimer plays no further role in connecting other entities in the supramolecular network. Thus, the water dimer with a double hydrogen bond that is entrapped between the dinuclear units of 1 is noteworthy.…”

“…On the other hand, the distance between O4 (uncoordinated carboxylate oxygen) and O5 is 2.746 Å with ∠O–H···O of 175°. A relevant example with an O···O distance of 2.93 Å was reported, 33 but the water dimer plays no further role in connecting other entities in the supramolecular network. Thus, the water dimer with a double hydrogen bond that is entrapped between the dinuclear units of 1 is noteworthy.…”

“…Interestingly, three possible structures for dimer of water have been reported in the literature (Scheme S1). − A Cambridge Structural Database (CSD) search can result in several thousands of examples where the cyclic dimer structure is a part of larger clusters, such as the one reported recently; however, the difficulty in performing an autosearch to find the cyclic dimer structure, which only connects the hosts, is to be considered. Both open-chain and cyclic structures were observed in SCNs, while the bifurcated structure was identified in the gas phase. , Therefore, the encapsulation/entrapment of cyclic water dimer is of great interest at any time.…”

Unusual mixed-valence CuII/CuI coordination polymer based on 2,5-bis(pyridine-2-yl)-1,3,4-thiadiazole and thiocyanate: Synthesis, structural characterization and antimicrobial in vitro activity assessment

“…In addition, we were interested in coligand thiocyanate because it is well known that thiocyanate can also partially reduce in situ, Cu II to Cu I and thus leads to mixed valence Cu(I/II)-thiocyanate coordination polymers. This type of mixed-valence complex is more interesting than those of Fe or Co because the copper (I) and copper (II) metal centers prefer different geometries and the two oxidation states are very labile and stereo chemically flexible [39,40]. On the other hand, the chemistry of mixed-valence Cu II /Cu I coordination complexes are gaining popularity due to its great applications in various fields like as biological activity [41,42], electronic properties [43,44] and electrical conductivity [45,46].…”