Calcium alginate (CaAlg) is a kind of biodegradable and eco-friendly functional material, and CaAlg/reduced graphene oxide (rGO) composites are expected to be applied as new textile, heat-generating, and flame-retardant materials. In this paper, the CaAlg/rGO composites were prepared by a sol-gel method and their morphological and thermal properties were studied. The results showed that the introduction of rGO can efficiently improve the thermal stability of CaAlg. Further study showed that rGO increased the carbon formation rate by 4.1%, indicating that the thermal stability was improved by the promotion of carbon formation. Moreover, the weight loss rate of the composites was faster at 180–200 °C than that of CaAlg, after which the rate was less comparatively, suggesting the better thermal stability of the composite. This maybe because the high heat transfer efficiency of rGO allowed the material to reach the temperature of the thermal decomposition of the glycan molecule chain within a short time, and then promoted carbon formation. The thermal cracking mechanism of the composites is proposed based on the experimental data.

Two new zinc coordination complexes, namely [Zn₂(tib)_4/3(L¹)₂]·DMA (1) and [Zn₂(tib)_4/3(L²)₂]·H₂O (2) (tib = 1,3,5-tris(1-imidazolyl)benzene, H₂L¹ = biphenyl-4,4′-dicarboxylic acid, H₂L² = 4,4′-(2,2′-oxybis(ethane-2,1-diyl)bis(oxy))dibenzoic acid and DMA = N,N-dimethylacetamide), are obtained using achiral mixed ligands and characterized using elemental analysis, IR and X-ray crystallography. Compounds 1 and 2 both display intriguing structural features of both interpenetration and self-catenation. By careful inspection of the two structures, we found that the Zn(II) cations, the tib ligands, and the dicarboxylic anions show the same coordination modes or analogous configurations. Compound 1 is chiral, which was confirmed by measuring the optical rotation of the bulk samples using solid-state circular dichroism (CD). It is comprised of two crystallographically independent interpenetrated 3D motifs, each containing interlaced triple-stranded right- and left-handed Zn–L¹–Zn helical chains and chiral 2D [Zn(tib)_2/3] layers. Both motifs display binodal (3,4)-coordinated 3D self-catenated networks with the point symbol (10³)₂(10⁶)₃ and the vertex symbols [10₁₃·10₁₃·10₁₃] and [10₇·10₇·10₈·10₁₀·10₁₁·10₁₁]. However, the two types of helical chains are not racemic due to the differences between the two kinds of L¹ anions, and the two types of chiral 2D [Zn(tib)_2/3]²⁺ layers are not enantiomeric either due to the different configurations of the tib ligands. Therefore, the two motifs are not enantiomers. Compound 2 is achiral, containing Zn–L²–Zn zigzag chains that span into three directions and chiral 2D [Zn(tib)_2/3] layers. The overall 3D network is a new binodal (3,4)-coordinated self-catenated network with the point symbol (10³)₂(10⁶)₃ and the vertex symbols [10₇·10₇·10₇] and [10₂·10₄·10₅·10₅·10₅·10₅]. Two of these networks interpenetrate. Their chiral and achiral structures are mainly modulated by the length of the dicarboxylates. As expected, compounds 1 and 2 show photoluminescence behaviors and compound 1 shows a ferroelectric behavior. Thermogravimetric studies of 1 and 2 have also been performed. We examined all 48 known structures containing the tib ligand and drew the conclusion that the metal + tib combination, modulated by the prolonged L ligands, can be a good basis for new chiral and catenated structures.

Two new entangled complexes, [Zn(bibp)(L¹)]·0.25H₂O (1) and [Co(bibp)(H₂L²)] (2) (bibp = 4,4′-bis(1-imidazolyl)biphenyl, H₂L¹ = 4,4′-(2,2′-oxybis(ethane-2,1-diyl)bis(oxy))dibenzoic acid, and H₄L² = 5,5′-(2,2′-oxybis(ethane-2,1-diyl)bis(oxy))diisophthalic acid), have been synthesized hydrothermally. Complex 1 features a new uninodal four-connected (6⁵·8) net with vertex symbol 6·6·6·6·6₂·8₂, which is different from all that exhibit uninodal four-connected (6⁵·8) nets found in the literature, including cds, dmp, ict, mok, unl and unm. Three of these nets interpenetrate. Complex 2 shows an unusual threefold 2-D → 3-D polythreaded framework, in which each 2-D wave-like net is formed by the intersection, at the shared Co nodes, of the 1-D left- and right-handed single-helical (H₂L²)²⁻ chains and the 1-D bibp meso-helices. Furthermore, the thermal and photoluminescent properties of 1 have also been studied.

This article represents two types of entanglements, [Co₂(bibp)(BTB)₂][Co(bibp)₂(H₂O)₂] (1) and [Co₃(bibp)₂(H₂O)₂(BTB)₂]·2H₂O·2DMF (2) (bibp = 4,4′-bis(1-imidazolyl)biphenyl and H₃BTB = 1,3,5-tris(4-carboxyphenyl)benzene), which are 2-D→3-D polycatenated frameworks formed by parallel catenation of 1-D+2-D→2-D polythreaded motifs based on the double-layered sheet penetrated by ribbons of rings (1) and a 2-D→3-D mutual polythreading of three double-layered sheets with dangling arms (2), which is assembled by the same initial materials by simply changing the volume ratio of water/DMF medium.