Zn Salphen Complexes Research Articles

Theoretical study of switching characteristics of molecular tweezers based on bis(Zn-salphen).

A series of novel tweezers based on bis(Zn-salphen) complex is theoretically studied. Density functional theory (DFT) method is used to investigate the switchable properties of terpy/bis(Zn-salphen) complex (1, terpy=2,2':6',2″-terpyridine) and Br-phtpy/bis(Zn-salphen) complex (2, Br-phtpy=4'-bromophenyl-2,2':6',2″-terpyridine). In this study, the free tweezers 1 and 2 can be converted from a "W" open form to a "U" closed form upon Ru(III) coordination. The switching performances were characterized by 1H NMR and absorption spectra. DFT calculations were carried out using a B3LYP-D3 functional and def2-SVP basis set for all atoms. 1H NMR spectra showed that terpyridine protons had an obvious upfield shift during complexation with RuCl3. The absorption spectrum was observed in the closed tweezers with a significant red shift and a decreased oscillator strength. In addition, the tweezers were reopened by introducing molecule pyrazine in the "U"-shaped conformation to form a host-guest system. The recognition ability of two Zn-salphen complexes was studied by geometrical optimization and absorption spectra.

Synthesis of a Novel Zn-Salphen Building Block and Its Acrylic Terpolymer Counterparts as Tunable Supramolecular Recognition Systems.

In this work, we present the synthesis of a novel Zn-Salphen complex containing an allyl group, which was used as building block in the further preparation of a new family of functional terpolymers. These polymers were obtained through radical co-polymerization with methyl metacrylate (MMA) and n-butyl acrylate (nBuA) in different ratios. The supramolecular recognition behavior of each polymer was evaluated via potentiometric measurements against selected anions in aqueous media. Interestingly, this proof of concept study shows that these systems were selective against only fluoride (F−) or both, fluoride and acetate (OAc−), by tailoring the relative content of Zn-Salphen monomer, thus making them a promising starting point for modular design of chemical sensors through straightforward synthetic approaches.

Optical biosensing using newly synthesized metal salphen complexes: A potential DNA diagnostic tool

A solid-state DNA optode sensor has been developed based on the employment of glutaraldehyde (GD)-activated aminated silica nanoparticles (SiO2NPs-NH2) DNA carrier matrix, and the newly synthesized yellowish N,N’-bis-5-(hydroxysalicylidene)phenylene-diamine-zinc(II) (i.e. the Zn salphen complex) oligonucleotide label. Some three Schiff base complexes with three different transition metal ions (Zn2+, Ni2+, Cu2+) were synthesized through a simple one-pot reaction (5h), and characterized by their physical and chemical properties based on FTIR, NMR and ESI–MS analyses. Due to the square planar geometry and aromatic ring structured characteristics of the metal complex intercalators, they could intercalate between DNA bases via π-π stacking interaction, and rendered a yellowish pink hue on the DNA biosensor surface. Reflectometric optimization revealed high selectivity of the nanosilica-based DNA biosensor in the detection of dengue serotype 2 DNA, which capable of discriminating even a single nucleotide mismatch. The optical DNA biosensor demonstrated a linear reflectance response between 1.0×10−15M and 1.0×10−11M cDNA (R2=0.9975) with a fast DNA hybridization time of 30min and a limit of detectable (LOD) DNA concentration as low as 1zM. In addition, this biosensor showed high shelf life stability with a 20-day operational duration and reusable for five consecutive DNA testings. The proposed optical DNA biosensor offers biosensing performance far superior to that of previously reported electrochemical DNA biosensor for early diagnosis of dengue infection with respect to dynamic linear range, LOD and response time.