Synthesis and characterization of transition metal complexes of hydrochloride salt of 3-chlorobenzaldehyde hydralazine hydrazone: a new class of possible anti-cariogenic agents

Copper Materials for Caries Management: A Scoping Review

This study comprehensively reviewed the types, properties and potential applications of copper materials for caries management. Two researchers independently searched English publications using PubMed, Scopus and Web of Science. They screened the titles and abstracts of publications presenting original studies for review. They included 34 publications on copper materials, which were categorized as copper and copper alloy materials (13/34, 38%), copper salt materials (13/34, 38%) and copper oxide materials (8/34, 24%). All reported copper materials inhibited the growth of cariogenic bacteria such as Streptococcus mutans and Candida albicans. The materials could be doped into topical agents, restorative fillers, dental adhesives, drinking water, dental implants, orthodontic appliances, mouthwash and sugar. Most publications (29/34, 83%) were laboratory studies, five (5/34, 14%) were animal studies and only one paper (1/34, 3%) was clinical research. In conclusion, copper and copper alloy materials, copper salt materials and copper oxide materials have an antimicrobial property that inhibits cariogenic bacteria and Candida albicans. These copper materials may be incorporated into dental materials and even drinking water and sugar for caries prevention. Most publications are laboratory studies. Further clinical studies are essential to validate the effectiveness of copper materials in caries prevention.

Two new zinc(II) and mercury(II) complexes based on N,N'-(cyclohexane-1,2-diylidene)bis(4-fluorobenzohydrazide): synthesis, crystal structures and antibacterial activities

Reaction of N,N'-(cyclohexane-1,2-diylidene)bis(4-fluorobenzohydrazide), C₂₀H₁₈F₂N₄O₂, (L^F), with zinc chloride and mercury(II) chloride produced different types and shapes of neutral coordination complexes, namely, dichlorido[N,N'-(cyclohexane-1,2-diylidene)bis(4-fluorobenzohydrazide)-κ²N,O]zinc(II), [ZnCl₂(C₂₀H₁₈F₂N₄O₂)], (1), and dichlorido[N,N'-(cyclohexane-1,2-diylidene)bis(4-fluorobenzohydrazide)-κ⁴O,N,N',O']mercury(II), [HgCl₂(C₂₀H₁₈F₂N₄O₂)], (2). The organic ligand and its metal complexes are characterized using various techniques: IR, UV-Vis and nuclear magnetic resonance (NMR) spectroscopies, in addition to powder X-ray diffraction (PXRD), single-crystal X-ray crystallography and microelemental analysis. Depending upon the data from these analyses and measurements, a typical tetrahedral geometry was confirmed for zinc complex (1), in which the Zn^II atom is located outside the bis(benzhydrazone) core. The Hg^II atom in (2) is found within the core and has a common octahedral structure. The in vitro antibacterial activities of the prepared compounds were evaluated against two different bacterial strains, i.e. gram positive Bacillus subtilis and gram negative Pseudomonas aeruginosa bacteria. The prepared compounds exhibited differentiated growth-inhibitory activities against these two bacterial strains based on the difference in their lipophilic nature and structural features.

Synthesis, mol-ecular and crystal structure of 1-(1,2-di-hydro-phthalazin-1-yl-idene)-2-[1-(thio-phen-2-yl)ethyl-idene]hydrazine

The title compound, C14H12N4S, was synthesized by the condensation reaction of hydralazine and 2-acetyl-thio-phene and during the reaction, a proton transfer from the imino nitro-gen atom to one of the endocylic nitro-gen atoms occurred. The compound crystallizes in the monoclinic crystal system with two independent mol-ecules (mol-ecules 1 and 2) in the asymmetric unit. In each mol-ecule, there is a slight difference in the orientation of the thio-phene ring with respect to phthalazine ring system, mol-ecule 1 showing a dihedral angle of 42.51 (1)° compared to 8.48 (1)° in mol-ecule 2. This implies an r.m.s deviation of 0.428 (1) Å between the two mol-ecules for the 19 non-H atoms. The two independent mol-ecules are connected via two N-H⋯N hydrogen bonds, forming dimers which inter-act by two bifurcated π-π stacking inter-actions to build tetra-meric motifs. The latter are packed in the ac plane via weak C-H⋯π inter-actions and along the b axis via C-H ⋯N and C-H⋯π inter-actions. This results a three-dimensional architecture with a tilted herringbone packing mode.

Crystal structure of diaqua-(N-(1-(pyrazin-2-yl)ethylidene)pyridin-1-ium-4-carbohydrazonate-κ3 N,N′,O)-tris[nitrato-κ2 O,O′)lanthanum(III), C12H15N8O12La

C12H15N8O12La, monoclinic, P21/c (no. 14), a = 8.3267(7) Å, b = 28.348(2) Å, c = 9.1097(8) Å, β = 107.5410(10)°, V = 2050.3(3) Å3, Z = 4, R gt(F) = 0.0236, wR ref(F 2) = 0.0559, T = 296(2) K.

Crystal structure of bis(N-(1-(pyrazin-2-yl)ethylidene)nicotinohydrazonato-κ3 N,N′,O)cadmium(II) – methanol (1/1), C26H28N10O4Zn

C26H28N10O4Zn, monoclinic, C2/c (no. 15), a = 14.507(4) Å, b = 16.776(5) Å, c = 12.151(3) Å, β = 108.596(4)°, V = 2802.8(13) Å3, Z = 4, R gt(F) = 0.0258, wR ref(F 2) = 0.0719, T = 293(2) K.

Crystal structure of hexaaqua-{(E)-N′-(1-(pyrazin-2-yl)ethylidene)isonicotinohydrazide-κ3 N,N′,O}praseodym(III) trichloride monohydrate, C12H25Cl3N5O8Pr

C12H25Cl3N5O8Pr, triclinic, P1̄ (no. 2), a = 9.4800(10) Å, b = 9.9591(12) Å, c = 12.4897(143) Å, α = 88.855(2)°, β = 76.897(2)°, γ = 89.182(2)°, V = 1148.2(2) Å3, Z = 2, R gt(F) = 0.0372, wR ref(F 2) = 0.0918, T = 296(2) K.

Crystal structure of diaqua-(N-(1-(pyrazin-2-yl)ethylidene)nicotinohydrazonato-κ3 N,N′,O)-bis(nitrato-κ2 O,O′)samarium(III), C12H14N7O9Sm

C12H14N7O9Sm, monoclinic, P21/c (no. 14), a = 16.770(3) Å, b = 7.7185(16) Å, c = 15.165(3) Å, β = 108.409(3)°, V = 1862.5(7) Å3, Z = 4, R gt(F) = 0.0262, wR ref(F 2) = 0.0672, T = 296(2) K.

Crystal structure of bis(N-(1-(pyrazin-2-yl)ethylidene)nicotinohydrazonato-κ3 N,N′,O)copper(II) C24H20N10O2Cu

C24H20N10O2Cu, orthorhombic, Aba2 (no. 41), a = 12.2281(16) Å, b = 19.176(3) Å, c = 9.8689(13) Å, V = 2314.1(5) Å3, Z = 4, R gt(F) = 0.0381, wR ref(F 2) = 0.0752, T = 296(3) K.

Crystal structure of diaqua-dinitrato-k2 O,O′((Z)-N-((E)-1-(pyrazin-2-yl)ethylidene)nicotinohydrazonato-k3 N,N′,O)europium(II), C12H14N7O9Eu

C12H14N7O9Eu, monoclinic, P21/c (no. 14), a = 16.770(3) Å, b = 7.7185(16) Å, c = 15.165(3) Å, β = 108.409(3)°, V = 1862.5(7) Å3, Z = 4, R gt(F) = 0.0174, wR ref(F 2) = 0.0453, T = 296(2) K.