Synthesis, crystal structures and photocatalytic properties of Zn(II), Ni(II), Co(II) complexes with a symmetric open-chain N2O4-donor bis-Schiff base ligand

Abstract

Three complexes, Zn(C 40 H 36 N 4 O 8 )Á3CH 3 OH (1), Ni(C 40 H 36 N 4 O 8 )Á3CH 3 OH (2) and Co(C 40 H 36 N 4 O 8 )Á3CH 3 OH (3), with a sexidentate (N 2 O 4 ) symmetric bis-Schiff base ligand (C 40 H 36 N 4 O 8 = 1,2-bis(2-methoxy-6-formylphenoxy) ethane-L-tryptophan) have been synthesized and characterized by physicochemical and spectroscopic methods. The X-ray crystal structures show that the metal atoms of three complexes are all six-coordinated by two nitrogens from C=N groups, two oxygens from ether groups and two carboxylic oxygens in the mono-ligand, forming a distorted octahedral geometry. The complexes were screened as photocatalysts for the degradation of methylene blue, rhodamine B and methyl violet. All three complexes proved to be good candidates for the photocatalytic degradation of methylene blue and complexes 2-3 are also good photocatalysts for the degradation of rhodamine B. The mechanism of these photocatalytic degradations is discussed.

Photocatalytic Decontamination of Wastewater Containing Organic Dyes by Metal–Organic Frameworks and their Derivatives

“…The photocatalytic reactioni s processed based on the highest occupied molecular orbital (HOMO,t he VB) and the lowest unoccupied molecular orbital (LUMO, the CB). [42,56,64,83] Under visible-light irradiation, the electrons (e À1 )i nt he VB are excited to theC Bw ith holes (h + ) left in the VB. [39,48,55] The adsorbed oxygen (O 2 )c an accept e À1 to form the oxygen radicals (CO 2 À )( O 2 + e À !CO 2 À ), and it further transformsi ntoa ctive COH (CO 2…”

“…[100,102] For the purpose of understanding the universality or selectivity of the catalyst for dye degradation, twelve kinds of azo dyes, namely MO, Acid Orange 7( AO7), Orange I( OI), Orange IV (OIV), Orange G( OG), Congo Red (CR), Acid Red 27 (AR27), SunsetY ellow (SY), Amido Black 10B (AB10B), AnilineB lack (AB), Acid Chrome Blue K( ACBK), and Eriochrome Black T( EBT) were photodegraded under UV light by the Ag I -doped coordination polymer [(Pb(Tab) 2 (bpe)) 2 (PF 6 ) 4 ·1. 64 AgNO 3 ] n (Tab = 4-(trimethylammonio)benzenethiol, bpe = 1,2-bis(4-pyridyl)ethylene), which is prepared by an ambient-temperature solid-state reaction. [62] The photodegradation efficiency of MO, OIV,a nd OG are about 95 %, 85 %, and 95 %u nder irradiation for5 0, 60, and 40 min, respectively.I na ddition, severalo ther dyes, AO7, OI, CR, AR27, SY,A B10B, AB,A CBK, and EBT are almost completely degraded after illumination for 30, 30, 3, 50, 40, 12, 20, 40, 15 min, respectively.S uch photocatalytic performances are better than [(Pb(Tab) 2 ) 2 (PF 6 ) 4 ] n and [(Pb(Tab) 2 (bpe)) 2 (PF 6 ) 4 ] n , which indicates the excellent adaptability of the Ag I -doped coordination polymer for the elimination of variousa zo dyes in water.A dditionally,[ (Pb(Tab) 2 (bpe)) 2 (PF 6 ) 4 ·1.…”

“…[62] The photodegradation efficiency of MO, OIV,a nd OG are about 95 %, 85 %, and 95 %u nder irradiation for5 0, 60, and 40 min, respectively.I na ddition, severalo ther dyes, AO7, OI, CR, AR27, SY,A B10B, AB,A CBK, and EBT are almost completely degraded after illumination for 30, 30, 3, 50, 40, 12, 20, 40, 15 min, respectively.S uch photocatalytic performances are better than [(Pb(Tab) 2 ) 2 (PF 6 ) 4 ] n and [(Pb(Tab) 2 (bpe)) 2 (PF 6 ) 4 ] n , which indicates the excellent adaptability of the Ag I -doped coordination polymer for the elimination of variousa zo dyes in water.A dditionally,[ (Pb(Tab) 2 (bpe)) 2 (PF 6 ) 4 ·1. 64 AgNO 3 ] n can be reused more than fivet imes without evident photocatalytic efficiencyd ecay of CR and AB10B. The narrow E g may be the reason for the higherp hotocatalytic activity.A fter the Ag + is doped onto the network of [(Pb(Tab) 2 (bpe)) 2 (PF 6 ) 4 ] n (E g = 2.52 eV), an ew lower energy level (CB) can be generatedb etween the 4d orbitalo fA g + and the CB of [(Pb(Tab) 2 (bpe)) 2 (PF 6 ) 4 ] n ,w hich results in the E g (2.46 eV) decrease and thus facilitates electron excitation for the quick generation of radicals pecies.…”

Study of the Degradation of Dyes by a Mononuclear Copper Complex Forming a Zigzag Chain

“…This technique is effective in wastewater treatment and has helped a lot to effectively degrade organic pollutants such as textile dyes, especially since this technique is environmentally friendly and cost-effective. Several studies have recently been conducted in this direction [31][32][33][34].…”