A robust polyoxometalate-templated four-fold interpenetrating metal-organic framework showing efficient organic dye photodegradation in various pH aqueous solutions.

A Keggin-type polyoxometalate (POM)-templated metal-organic framework, [Cd(TTPB-4)(DMF)3]4[PMo12O40]2[HPMo12O40]·6DMF·4H2O (1), based on a newly designed linker of TTPB-4 [TTPB-4 = 1,3,5-tris(4-(4H-1,2,4-triazol-4-yl)phenyl)benzene], has been hydrothermally synthesized and characterized using IR, XRD, TGA, UV-Vis and photoluminescence spectra. Single-crystal X-ray crystallography reveals that 1 represents a unique POM-templated four-fold interpenetrated 3-D coordination network. The POM-templated MOF of 1 exhibits strong chemical stability that can withstand aqueous solutions of various pH-values (2-10). Particularly, 1 possesses excellent photodegradation activity and recyclability towards the organic dyes of Crystal Violet (CV) and Basic Red 2 in aqueous solutions with different pH values.

Luminescent Three- and Four-Coordinate Dinuclear Copper(I) Complexes Triply Bridged by Bis(diphenylphosphino)methane and Functionalized 3-(2'-Pyridyl)-1,2,4-triazole Ligands.

A new series of bimetallic Cu(I) complexes 1-5 triply bridged by a monoanionic or charge-neutral functionalized 3-(2'-pyridyl)-1,2,4-triazole in a µ-η1(N),η2(N,N) tridentate binding mode and two bis(diphenylphosphino)methane (dppm) ligands have been synthesized. Complexes 1-5 are singly or doubly charged dinuclear Cu(I) species with an eight-membered Cu2C2P4 ring of {Cu(µ-dppm)2Cu} unit, in which 3 and 4 adopt the boat-boat conformation, while 1, 2, and 5 display the chair-boat form. In these dimeric copper(I) complex cations, one of the two Cu(I) ions is four-coordinated, in a highly distorted N2P2 tetrahedral environment and the other is three-coordinated, in a distorted NP2 trigonal planar arrangement. All these Cu(I) complexes exhibit a comparatively weak low-energy absorption in CH2Cl2 solution, ascribed to the charge-transfer transitions with appreciable 1MLCT contribution, as suggested by time-dependent density functional theory (TDDFT) analyses. Complexes 1-5 display good emission properties in both solution and solid states at ambient temperature, which are well-modulated via structural modification of 3-(2'-pyridyl)-1,2,4-triazole, including the alteration of the substituent type (-CF3, -H, -CH3, and -C(CH3)3) and position (ortho-, meta-, and para-position). Furthermore, the variation of the substituent (-CF3 and -C(CH3)3) on the 5-site of the 1,2,4-triazolyl ring markedly influences the proton activity of the 1,2,4-triazolyl-NH, thus leading to the formation of both singly and doubly charged bimetallic Cu(I) species regulated by the NH ↔ N- conversion, resulting from NH deprotonation of the 1,2,4-triazolyl ring.