New Coordination Polymers of Copper(I) and Silver(I) with Pyrazine and Piperazine: A Step Toward “Green” Chemistry and Optoelectronic Applications

Abstract

Five coordination polymers and one hexanuclear cluster have been obtained, and their crystal structures were determined upon reaction of Cu(I) or Ag(I) precursors with pyrazine (Pyz) or piperazine (Ppz). Five complexes are mixed-imine-ligand with anionic-fluorinated pyrazolate [3,5-(CF)Pz] ([Pz]) besides Pyz or Ppz, whereas the sixth had the neutral diimine as a single chromophore. Complexes 1-3 are isomers of the same Cu/Pz/Pyz composition with the same or different unit cell stoichiometry, namely, {Cu[3,5-(CF)Pz](Pyz)(CHCl)} (1·CHCl), {Cu[3,5-(CF)Pz]}(Pyz)·toluene} (2·toluene), and {Cu[3,5-(CF)Pz](Pyz)·1.5benzene} (3·1.5benzene), respectively. Altering only the metal attains {Ag[3,5-(CF)Pz](Pyz)·2benzene} (4·2benzene), while also changing the neutral diimine attains {Ag[3,5-(CF)Pz](Ppz)} (5). Using Pyz without an anionic imine yields {[Cu(Pyz)(MeCN)][BF]} (6). The crystal structure of 1 shows two trimers linked together with two pyrazine ligands. Crystals of 2 represent a metal-organic framework (MOF-TW1) with significant surface area (1278 m/g) and porosity (23.7% void volume) without considering toluene adsorbates in channels. MOF-TW1 was obtained serendipitously upon a reaction attempt to attain a mixed-metal product, instead attaining a Cu(I)-only product with interconnected four-coordinate dinuclear units. Likewise, 3 was obtained through a transmetalation of all Ag atoms in 4 to replace them by Cu atoms. Three reactions (to obtain 1, 4, and 5) were successfully carried out by both solvent-mediated and solventless transformations, whereas 2 and 3 were obtained only by solvent-mediated reactions, while 6 was attainable only by solventless transformations. The solventless transformations occurred either by sublimation and vapor diffusion or by mechanical grinding at ambient laboratory conditions-without the aid of heating, high pressure, vacuum, or any automated equipment. All transformations could be monitored by the human eye as the reaction progresses, as evidenced by progressive discoloration and/or luminescence changes. All crystal structures were obtained with the aid of conventional crystal growth methods from organic solvents for bulk products obtained from both solvelntless and solvent-mediated reactions. Powder X-ray diffraction was used to compare bulk products with one another and the crystallographic products. All Cu(I) products are colored and nonluminescent; the progress of their vapor diffusion-based solventless reactions can be followed by gradual discoloration of white solid reactants and/or quenching precursor's phosphorescence. Both Ag(I) products were colorless with 4 being luminescent but not 5.

Dicopper(I) Complexes Incorporating Acetylide-Functionalized Pyridinyl-Based Ligands: Synthesis, Structural, and Photovoltaic Studies

“…Almost all complexes exhibited a broad green to blue emission (λ em = 358−486 nm) in solution without any vibronic progression at room temperature (RT), which is consistent with related Cu(I) complexes. 28 The emission wavelength of the complexes shifted bathochromically on moving from complex 1 (358 nm) through 2 (435 nm) to 3 (479 nm). The nature and extent of shifting unarguably indicated conjugation-directed luminescence control in these complexes.…”

Colossal Dielectric Responses from the Wide Band Gap 2D-Semiconducting Amine Templated Hybrid Framework Materials

“…An extensive study of hybrid frameworks shows that, as compared to the traditional silicate, phosphate, and sulfate tetrahedra with fewer coordination sites, − organophosphonate units are the best possible sources for the organic component in such materials, with their multiple coordination sites being extremely useful toward the design of higher-dimensional hybrid frameworks with host–guest interactions. − Presently, metal organophosphonates are a well-investigated class of hybrid frameworks with their exciting structure–property relationship, − though their potential uses based upon their dielectric behavior has not been reported so far. Silver­(I) ions, by their inherent chemical nature of irregular coordination number and geometry, are best suited for isolating fascinating hybrid frameworks. − However, the amine-templated silver­(I) phosphonate frameworks have not been thoroughly investigated to date.…”

Soft Metal Cations Trigger Sandwich‐Cluster Luminescence of a New Au(I)‐Vinylimidazolate Cyclic Trinuclear Complex

“…[3][4][5] These d 10 -metal CTCs have been attracting attentions due to their potentials as luminophores (for sensing or optoelectronic devices), acid-base chemistry, supramolecular assemblies, and MÀ M or MÀ M' bonding-potentially tuning all of which by easily manipulating the combinations of metals, ligands, and substituents. [6][7][8][9][10][11][12][13][14][15][16][17] Beyond that, ordered materials constructed from CTCs are being pursued in very recent years for their controllable skeletons and excellent optical/catalytic performances. [18][19][20][21][22][23][24][25] The clusters herein are formed by sandwiching a foreign closed-shell metal cation between two gold(I) CTC molecules, resulting in an [Au 3 ]…M + …[Au 3 ] chemical formula for the resulting heptanuclear cluster.…”