Lanthanide‐Coordination Polymers with Pyridinedicarboxylic Acids: Syntheses, Structures, and Luminescent Properties

Abstract

Five lanthanide coordination polymers (Ln‐CPs) based on pyridine‐dicarboxylate and lanthanide metal ions were synthesized and characterized, namely [Sm(pydc)(Hpydc)(H2O)5]·4H2O (1) (H2pydc = 2, 5‐pyridine‐dicarboxylic acid), [Ho(pydc)(Hpydc)(H2O)3]n·4nH2O (2), [Ce(pydc)(bdc)(H2O)]n (3) (H2bdc = 1, 4‐benzenedicarboxylic acid), [Nd2(dipic)3(H2O)3]n (4), and [Pr2Ag2(dipic)4(H2O)5]n·5nH2O (5) (H2dipic = 3, 5‐pyridine‐dicarboxylic acid). Complexes 1 and 2 display mononuclear structure and 1D zigzag chains, respectively. In complex 3, the CeIII ions are connected through pydc2– and bdc2– ligands to generate an intricate 3D architecture. Complex 4 is constructed through dinuclear {Nd2} SBUs and oxygen bridging from carboxyl groups of dipic2– to generate a 3D framework. In 5, PrIII ions and AgI ions are assembled into a 2D heterometallic layer, in which the rare Ag···Ag weak interactions are observed. Furthermore, the solid state luminescent properties of 1–4 were measured and discussed.

Two Three‐Dimensional Actinide–Silver Heterometallic Coordination Polymers Based on 2,2′‐Bipyridine‐3,3′‐dicarboxylic Acid with Helical Chains Containing Dimeric or Trimeric Motifs

“…The Ag I ion is coordinated to four nitrogen atoms from two distinct bpdc 2– ligands with Ag–N bond lengths of 2.173(7), 2.178(7), 2.592(8), and 2.685(8) Å and a N1–Ag1–N3 angle of 169.4(3)°, and these values are consistent with previously reported values for silver pyridyl compounds. [2a], Each thorium trimer is coordinated to six bpdc 2– ligands, which adopt two different coordination modes, namely, µ 3 ‐η 1 :η 1 :η 1 :η 1 :η 1 :η 1 bidentate chelating mode (Scheme c) and µ 5 ‐η 1 :η 1 :η 1 :η 1 :η 1 :η 1 monodentate bridging mode (Scheme d), through carboxyl oxygen atoms to form a chain of –[Th 3 (µ 3 ‐OH)(µ 2 ‐OH) 3 (µ 3 ‐bpdc) 3 –Th 3 (µ 3 ‐O)(µ 3 ‐OH) 3 (µ 5 ‐bpdc) 3 ] n –, which contains three strands of –[Th2‐(µ 3 ‐bpdc)‐Th1‐(µ 5 ‐bpdc) 2 ] n – left‐handed helical chains along the c direction with a pitch of 13.57 Å (Figure a and b). All of the helical chains in 2 are left‐handed and further bridged to each other along the ab plane by Ag I ions to form a 3D chiral framework (Figure c).…”

“…The absence of characteristic absorption bands at ν̃ = 1730–1690 cm –1 indicates that the carboxylate groups are coordinated completely to the metal centers in 1 and 2 . [5f], Moreover, a strong absorption peak at ν̃ = 1386 cm –1 for 2 indicates the presence of nitrate groups. [5e] These results are consistent with the results of the single‐crystal structural analyses.…”

In situ surface film evolution during Mg aqueous corrosion in presence of selected carboxylates

“…In contrast, IR spectra recorded after exposure to the flow-cell demonstrate some differences as compared to the spectrum of PDC solution (see Table 5, Fig. 5b, [65][66][67][68]). Band at 1724 cm -1 , attributed to C=O stretching vibration appears on spectra of wet Mg sample; bands in range of 1580 -1610 cm -1 attributed to asymmetric stretching modes of COOgroups [66,67] are shifted.…”

“…Analysis of IR spectra of CP-Mg342 (Fig. 5b) demonstrated that bands of carboxylates (COO -) were shifted as compared to the solution spectra (1607 -ν as , 1457 -ν s [68]). Band at 1724 cm -1 corresponding to C=O stretching of COOH, is absent in the PDC solution spectrum and appears in the spectrum of Mg sample, suggesting that the delocalization of electron density of carboxylic group disappears, instead the -(C=O)-Ois taking place; which can be schematically illustrated by a mechanism shown in Fig.…”

Synthesis, Crystal Structures and Photoluminescent Properties of One-Dimensional Europium(III)- and Terbium(III)-Glutarate Coordination Polymers, and Their Applications for the Sensing of Fe3+ and Nitroaromatics

“…Choosing appropriate ligands to increase the excited state lifetime and quantum yield (the light output) of lanthanide(III) complexes is thus essential for the development of improved luminescent materials (Li and Yan, 2012). In this regard, aromatic carboxylic acids such as, terephthalic acid (Daiguebonne et al, 2008; Wang et al, 2012) benzene-carboxylic acids (Yan et al, 2005; Wang et al, 2010b, 2012; Zhuravlev et al, 2011; Gai et al, 2013), and pyridine-dicarboxylic acid (Reinhard and Güdel, 2002; Huang et al, 2008; Zhu et al, 2009; Song et al, 2016; Xiang et al, 2017; Kumar et al, 2018) have been particularly used to design luminescent lanthanide coordination polymers. A number of studies also exist on the complexes of aliphatic carboxylic acids such as, malonic acid (Hussain et al, 2019), succinic acid (Cui et al, 2005; De Oliveira et al, 2013), glutaric acid (Głowiak et al, 1987; Legendziewicz et al, 1999; Antic-Fidancev et al, 2002), and adipic acid (Wang et al, 2010b).…”