Tuning of gallery heights in a crystalline 2D carbon nitride network

Abstract

Poly(triazine imide)-a 2D layered network-can be obtained as an intercalation compound with halides from the ionothermal condensation of dicyandiamide in a eutectic salt melt. The gallery height of the intercalated material can be tuned via the composition of the eutectic melt and by post-synthetic modification. Here, we report the synthesis of poly(triazine imide) with intercalated bromide ions (PTI/Br) from a lithium bromide and potassium bromide salt melt. PTI/Br has a hexagonal unit-cell demonstrating that the gallery height is synthetically tuneable in these materials.

Pharaoh's Serpents: New Insights into a Classic Carbon Nitride Material

“…These spectra more closely resemble the 15 N CP-MAS measured for the Pharaoh's serpent material than those of PTI·LiCl, [41] PTI·LiBr, [42] or PTI·HBr. [37] We note that Lotsch et al [11] prepared a 15 N-enriched sample of Liebig's melon that allowed them to observe of a small signal at approximately -225 ppm (δ =156 ppm relative to MeNO 2 ) that could be unambiguously assigned to the central N c atom of the heptazine structural unit.…”

“…[41] The resonances at δ = 162.6 and 157.9 ppm showed a rapid CP build up and could be assigned to 13 C environments close to the bridging -NHgroups, whereas the peak at δ = 168 ppm was attributed to C atoms adjacent to nonprotonated N atoms. Three peaks at 167.9, 162.6, and 157.8 ppm were also observed for PTI·LiBr with CP dynamics similar to those in PTI·LiCl, [42] although the intensity of the 157.8 ppm peak was significantly smaller than the other two in the single-pulse 13 C MAS NMR spectrum. These observations may suggest that the Pharaoh's serpent material has a structure based on triazine (C 3 N 3 ) rings linked via bridging -N=, along with some -NH-units, as found in the g-C 3 N 4 , TGCN, and PTI structures, with the possibility that some three-dimensional linking might occur to form polymeric units as predicted by theoretical studies.…”

Carbon nitrides: synthesis and characterization of a new class of functional materials

“…27 It should be noted that all PTI materials examined to date maintain a significant H concentration as an essential component of their structure, as the substitution by Li is always only partial. 25,26,68,69 3. Characterization of carbon nitride materials: techniques and challenges…”

Carbon nitride frameworks and dense crystalline polymorphs

“…Within the C-N-H system, materials related to Liebig's melon ((C 6 N 9 H 3 ) n ) contain tris-triazine (heptazine: C 6 N 7 ) structural units linked via -NH-groups 1,2,7-9 . Additional graphitic materials containing intercalated Li + , Cl − and Br − ions are formed by polytriazine imide (PTI) layers consisting of triazine (C 3 N 3 ) rings linked by -N= or -NH-species [10][11][12][13] . Synthesis of macroscopic flakes of triazine-based graphitic carbon nitride (TGCN) composed of nitrogen-linked triazine (C 3 N 3 ) units was reported recently 14 .…”