1,10-phenanthroline-2,9-dicarboxamides of various structure were synthesized and studied as ligands for separation and sensing of d-and f-metals. It was found that the extraction ability of dialkyl-diaryl-diamide to lanthanides decreases from La to Lu and extraction of Am is close to light lanthanides (La-Pr). Tetraalkyl-diamide are not selective to lanthanides, instead exhibiting moderate selectivity in Am/Ln separation. The diamide complexes with lanthanides and d-elements were synthesized and characterized by XRD analysis. All diamides have demonstrated good extraction ability to environmentally hazardous metals (cadmium, lead, copper). The synthesized compounds were also tested as ionophores in PVC-plasticized potentiometric sensor membranes. Such sensors displayed no perceptible response to lanthanides but exhibited high sensitivity towards copper, zinc, cadmium and lead. These compositions can be considered as promising cross-sensitive sensors for multisensor systems.

The reaction of cis-[PdCl(CNXyl)] (Xyl = 2,6-MeCH) with various 1,3-thiazol- and 1,3,4-thiadiazol-2-amines in chloroform gives a mixture of two regioisomeric binuclear diaminocarbene complexes. For 1,3-thiazol-2-amines the isomeric ratio depends on the reaction conditions and kinetically (KRs) or thermodynamically (TRs) controlled regioisomers were obtained at room temperature and on heating, respectively. In CHCl solutions, the isomers are subject to reversible isomerization accompanied with the cleavage of Pd-N and С-N bonds in the carbene fragment XylNCN(R)Xyl. Results of DFT calculations followed by the topological analysis of the electron density distribution within the formalism of Bader's theory (AIM method) reveal that in CHCl solution the relative stability of the regioisomers (∆G = 1.2 kcal/mol; ∆G = 3.2 kcal/mol) is determined by the energy difference between two types of the intramolecular chalcogen bonds, viz. S•••Cl in KRs (2.8-3.0 kcal/mol) and S•••N in TRs (4.6-5.3 kcal/mol). In the case of the 1,3,4-thiadiazol-2-amines, the regioisomers are formed in approximately equal amounts and, accordingly, the energy difference between these species is only 0.1 kcal/mol in terms of ∆G (∆G = 2.1 kcal/mol). The regioisomers were characterized by elemental analyses (C, H, N), HRESI-MS and FTIR, 1D (H, C) and 2D (H,H-COSY, H,H-NOESY, H,C-HSQC, H,C-HMBC) NMR spectroscopies, and structures of six complexes (three KRs and three TRs) were elucidated by single-crystal X-ray diffraction.

The solution-state emission profiles of a series of dinuclear Au(I) complexes 4-6 of the general formula Au2(NHC-(CH2)n-NHC)2Br2, where NHC = N-benzylbenzimidazol-2-ylidene and n = 1-3, were found to be markedly different from each other and dependent on the presence of excess bromide. The addition of excess bromide to the solutions of 4 and 6 leads to red shifts of ca. 60 nm, and in the case of 5, which is nonemissive when neat, green luminescence emerges. A detailed computational study undertaken to rationalize the observed behavior revealed the determining role aurophilicity plays in the photophysics of these compounds, and the formation of exciplexes between the complex cations and solvent molecules or counterions was demonstrated to significantly decrease the Au-Au distance in the triplet excited state. A direct dependence of the emission wavelength on the strength of the intracationic aurophilic contact allows for a controlled manipulation of the emission energy by varying the linker length of a diNHC ligand and by judicial choice of counterions or solvent. Such unique stimuli-responsive solution-state behavior is of interest to prospective applications in medical diagnostics, bioimaging, and sensing. In the solid, the investigated complexes are intensely phosphorescent and, notably, 5 and 6 exhibit reversible luminescent mechanochromism arising from amorphization accompanied by the loss of co-crystallized methanol molecules. The mechano-responsive properties are also likely to be related to changes in bromide coordination and the ensuing alterations of intramolecular aurophilic interactions. Somewhat surprisingly, the photophysics of NHC ligand precursors 2 and 3 is related to the formation of ground-state associates with bromide counterions through hydrogen bonding, whereas 1 does not appear to bind its counterions.

Two (1,3,5-triazapentadiene/ato)PtII complexes, [1][(Cl)2] and [2][(Cl)2], were synthesized by the previously reported platinum-mediated nitrile−amidine coupling. Both complexes crystallize as mixed chloroform−ethanol solvate [1][(Cl)2(CHCl3)7(EtOH)2] and [2][(Cl)2(CHCl3)6(EtOH)2] from the reaction mixture by slow evaporation of the commercial chloroform (containing ca. 1% of EtOH) taken as the solvent, while crystals of [2][(Cl)2(CHCl3)4] were obtained when distilled chloroform was employed. In the crystal structure of [1][(Cl)2(CHCl3)7(EtOH)2], [2][(Cl)2(CHCl3)6(EtOH)2], and [2][(Cl)2(CHCl3)4] solvates, the Cl− ion interacts with [1]2+ or [2]2+ by means of hydrogen bonding and via one hydrogen bridge, thus forming stacked arrays. The negatively charged cluster ions [Cl−(CHCl3) n ] (n = 2, 3) are stabilized via C−H···Cl− hydrogen bridges between the Cl− ion and CHCl3 molecules. In [1][(Cl)2(CHCl3)7(EtOH)2], two chloroform clusters dimerize to the [Cl−(CHCl3)3]2 species, where the halogen bonding between one Cl atom of CHCl3 and Cl− anion was detected. The halogen bonding was studied by theoretical methods (B3LYP, MP2), including the bond energy, AIM, and NBO charge transfer analyzes.

Two previously reported 1, 3,5,7,3,6, chloride platinum(II) complexes [PtCl{HN=C(R)N=CN[C(Ph)=C(Ph)]C=NC(R)=NH}] (R = t Bu 1, Ph 2) form solvates with halomethanes 1•1¼CH2Cl2, 1•1⅖CH2Br2, and 2•CHCl3. All these species featuring novel complex-solvent heterotetrameric clusters, where the structural units are linked by simultaneous two C-X•••Cl-Pt (X = Cl, Br) halogen and two C-H•••Cl-Pt hydrogen bonds. The geometric parameters of these weak interactions were determined by single-crystal XRD, and the nature of XB's and HB's in the clusters were studied for the isolated model systems (1)2•(CH2Cl2)2, (1)2•(CH2Br2)2, and (2)2•(CHCl3)2 by DFT calculations and Bader's AIM analysis. The evaluated energies of the weak interactions are in the range 0.9-3.0 kcal/mol. The XB's and HB's in the reported clusters are cooperative. In the cases of (1)2•(CH2Cl2)2 and (1)2•(CH2Br2)2, the contribution of HB's to the stabilization of the system is dominant, whereas for (2)2•(CHCl3)2 contributions of both types of non-covalent interactions are almost the same. Crystal packing and other forces such as, e.g. dipole-dipole interactions, also affect the formation of the clusters.