Surfactant‐Assisted Nanocrystalline Zinc Coordination Polymers: Controlled Particle Sizes and Synergistic Effects in Catalysis

Abstract

Different morphologies and particle sizes of two crystalline zinc-based coordination polymers (CPs), [Zn(pytz)H2 O]n (1; H2 pytz=2,6-bis(tetrazole)pyridine) and [Zn2 (pytz)2 4 H2 O] (2), from the bulk scale to the nanoscale, could be obtained under solvothermal conditions with different surfactants (polyvinylpyrrolidone (PVP) or polyethylene glycol (PEG) 2000) as templates. PVP and PEG 2000 could act as capping and structure-directing agents, respectively, to influence the growth of crystalline particles and control their sizes. CP 1 exhibits a two-dimensional framework with window-like units and 2 shows a bimetallic structure. Nanocrystalline 1 and 2 were used as heterogeneous catalysts to study how adjacent catalytic active sites synergistically effected their catalytic reactivities in the direct catalytic conversion of aromatic dinitriles into oxazolines. The results showed that 1 produced bis-oxazolines as the sole products, whereas 2 gave the mono-oxazolines as the major products under the same reaction conditions.

Heteroleptic Complexes of the Tridentate Pyridine‐2,6‐di‐tetrazolate Ligand

“…Reactions of in situ deprotonated H 2 pydtz in MeOH or EtOH (using NaOH or KOH) with divalent metal salts such as Co(II), Ni(II), Cu(II) or Zn(II) leads to rapid precipitation of virtually insoluble material of unclear composition. In a preceding study, we solved this problem by reacting the components at elevated temperatures using autoclaves (quasi solvothermal), similar to what was reported for the synthesis of the coordination polymers [Zn(pydtz)(H 2 O)] n and [Zn 2 (pydtz) 2 (H 2 O) 4 ] . However, single crystals and pure materials were obtained only directly from the synthesis, because recrystallisation from organic solvents or H 2 O proved impossible.…”

“…In contrast to the large number of transition metal complexes of the pydic 2− ligand, and the substantial coordination chemistry of tetrazoles in general, the coordination chemistry of the ligand pydtz 2− constitutes a new research area. Very recently, [Zn(pydtz)(H 2 O)] n and [Zn 2 (pydtz) 2 (H 2 O) 4 ] coordination polymers were reported . Luminescent homoleptic lanthanide(III) complexes (NHEt 3 ) 3 [Ln(pydtz) 3 ],, heteroleptic Ru(II) complexes [Ru(pydtz)(terpy)] (terpy = 2,2’;6’,2’’‐terpyridine), and [Ru(pydtz)(ROOCterpy)] (ROOCterpy = 4,4’,4’’COOR‐terpyridine with R = H or Et), and heteroleptic Pt(II) complexes of the type [Pt(pydtz)(Py‐4‐R)] with 4‐substituted pyridine as coligands, allowing their anchoring to various materials have been studied so far.…”

Reversible Structural Transformations of Metal–Organic Frameworks as Artificial Switchable Catalysts for Dynamic Control of Selectively Cyanation Reaction

“…[13][14][15][16][17][18] MOFs, with site isolation and adjacent active catalytic sites, which have been obtained throughd irect use or postsynthetic functionalization, as single-site and cooperative catalysts for chemical transformations have been investigated. [19][20][21][22][23][24][25][26][27] Ta king advantage of their frequently occurring reversible structural transformations, through single-crystal to single-crystal processes,t he uniquef lipping motion between structurala nd topologyc onnectionsa re similart oe ach otherm akes MOFs a highly appropriate choice for building molecular devices,s uch as switching or sensing materials. [28][29][30][31][32] Meanwhile,s olvent-induced dissolution-exchange-crystallization behavior is another important,but difficult, approach to regulating reversible structural transformations because the connection modesb etween metal ions and ligandsa re very difficult to re-edit.…”

“…As a wide variety of porous solid materials, MOFs have provided a well‐defined platform to engineer anchored molecular catalysts and demonstrated great potential in MOF‐based heterogeneous catalysis because of their accessible and uniform catalytic sites and massive and functionalized structural variations . MOFs, with site isolation and adjacent active catalytic sites, which have been obtained through direct use or postsynthetic functionalization, as single‐site and cooperative catalysts for chemical transformations have been investigated . Taking advantage of their frequently occurring reversible structural transformations, through single‐crystal to single‐crystal processes, the unique flipping motion between structural and topology connections are similar to each other makes MOFs a highly appropriate choice for building molecular devices, such as switching or sensing materials .…”

Direct Formation of Sub-Micron and Nanoparticles of a Bioinspired Coordination Polymer Based on Copper with Adenine

“…In this regard, coordination polymers have, among other interesting advantages, the facility to be nanoprocessed [14,15,16,17,18]. In recent years, a large number of nanostructured coordination polymers have been obtained through different processes, such as interfacial reactions, hydro-solvothermal reactions, microemulsions, or using ultrasound [19] and the use of surfactants [20]. However, probably the simplest procedure based on fast precipitation controlling the concentration of the reactants or the addition of a poor solvent to the reaction medium, can also be enough to produce a reduction from the microscale to the nanoscale size, which it is little developed.…”