Crystal Structure Solid-State Cross Polarization Magic Angle Spinning¹³C NMR Correlation in Luminescent d¹⁰Metal-Organic Frameworks Constructed with the 1,2-Bis(1,2,4-triazol-4-yl)ethane Ligand

Abstract

Hydrothermal reactions of 1,2-bis(1,2,4-triazol-4-yl)ethane (btre) with copper(II), zinc(II), and cadmium(II) salts have yielded the dinuclear complexes [Zn2Cl4(mu2-btre)2] (1) and [Zn2Br4(mu2-btre)2] (2), the one-dimensional coordination polymer infinity1[Zn(NCS)2(2-btre)] (3), the two-dimensional networks infinity2[Cu2(mu2-Cl)2(mu4-btre)] (4), infinity2[Cu2(mu2-Br)2(mu4-btre)] (5), and infinity2{[Cd6(mu3-OH)2(mu3-SO4)4(mu4-btre)3(H2O)6](SO4).6H2O} (6), and the three-dimensional frameworks infinity3{[Cu(mu4-btre)]ClO4.0.25H2O} (7), 3{[Zn(mu4-btre)(mu2-btre)](ClO4)2} (8), infinity3{[Cd(mu4-btre)(mu2-btre)](ClO4)2} (9), and infinity3[Cu2(mu2-CN)2(mu4-btre)] (10, 2-fold 3D interpenetrated framework). The copper-containing products 4, 5, 7, and 10 contain the metal in the +1 oxidation state, from a simultaneous redox and self-assembly reaction of the Cu(II) starting materials. The cyanide-containing framework 10 has captured the CN- ions from the oxidative btre decomposition. The perchlorate frameworks 7, 8, or 9 react in an aqueous NH4+PF6- solution with formation of the related PF6--containing frameworks. The differences in the metal-btre bridging mode (mu2-kappaN1:N1', mu2-kappaN1:N2 or mu4-kappaN1:N2:N1':N2') and the btre ligand symmetry can be correlated with different signal patterns in the 13C cross polarization magic angle spinning (CPMAS) NMR spectra. Compounds 2, 4, 5 and 7 to 10 exhibit fluorescence at 403-481 nm upon excitation at 270-373 nm which is not seen in the free btre ligand.

Spectroscopic characterization of schiff base-copper complexes immobilized in smectite clays

“…In a general way, blue structured emissions near 440 nm were observed (λ excitation at 374 nm) and assigned to metal to ligand charge transfer (MLCT) transitions, typical of d 10 copper(I) systems. 40 However, the photoluminescence spectra obtained for the [Cu(apzpn)]/LPN sample revealed a different pattern. As shown in Figure 4S, this sample exhibited a broad emission band centered at 580 nm, and excitation bands at 278, 325sh, 375, 420sh and 490 nm.…”

A Cadmium Anionic 1-D Coordination Polymer {[Cd(H2O)6][Cd2(atr)2(μ2-btc)2(H2O)4] 2H2O}n within a 3-D Supramolecular Charge-Assisted Hydrogen-Bonded and π-Stacking Network

“…The combination of neutral nitrogen donor ligands with anionic carboxylate ligands are frequent choices for the synthesis of mixed-ligand networks [22]. The linker 1,2-bis(1,2,4-triazol-4-yl)ethane (abbreviated as btre, Scheme 1) has recently been intensely studied in mixed-linker MOFs [19][20][21][22][23][24] and single-linker networks [25]. Herein, we report an attempt to construct a mixed-linker network with the 4,4 1 -bis(1,2,4-triazol-4-yl) (btr) ligand which was not hydrothermally stable under the synthesis conditions of 125˝C in water, so that the hydrolysis product 4-amino-1,2,4-triazole (atr) was incorporated instead (Scheme 1).…”

Synthesis, Crystal Structure, and Solid-State NMR Investigations of Heteronuclear Zn/Co Coordination Networks — A Comparative Study

“…Solid-state NMR is a versatile tool for studying the different interactions present in porous co-ordination frameworks, which is increasingly used for the characterization of structure and dynamics in these materials. [20][21][22][23][24] NMR spectra of solid samples provide information on the detailed local electronic structure of each nucleus reflected as chemical shift without the need of long-range order. Therefore, non-crystalline materials can be characterized with solid-state NMR which is increasingly used for the characterization of structure and dynamics in these materials.…”