IR spectroscopy and theoretical vibrational calculation of the melamine molecule

Wang, Yulin; Mebel, Alexander M.; Wu, Chung-Jen; Chen, Yit‐Tsong; Lin, Chin‐Feng; Jiang, Jyh-Chiang

doi:10.1039/a701732d

Cited by 89 publications

(75 citation statements)

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“…Although melamine is a well-known compound, the assignment of its IR absorption bands was only recently completed with the aid of theoretical vibrational calculations. 26 Two intense infrared peaks are observed for melamine at 1593-1598 cm -1 and 1438-1440 cm -1 in both the gas phase and solid argon matrix. By comparing the theoretical calculation and analysis of deuterated melamine spectra, the first band is assigned to the scissoring of the three NH 2 groups and the stretching of the triazine ring, while the second band is assigned to the ring and side chain CN stretching.…”

Section: Resultsmentioning

confidence: 99%

“…Comparing this to the gas phase and solid argon matrix, the absorption band is shifted to a higher frequency by about 60 cm -1 , well separated from the ring stretch absorption band at 1598 cm -1 . 26,27 It has been described that the ring stretches for aromatic and heteroaromatic rings can be divided into two different modes, the quadrant stretch and the semicircle stretch, as illustrated in Figure 2. 29a,b In the quadrant stretch, two-quarters of the ring contract while the other two-quarters of the ring stretch.…”

Section: Resultsmentioning

confidence: 99%

“…26,27,28 Since the 2C 18 TAZ is a dialkylsubstituted melamine, we assume the IR spectrum of 2C 18 TAZ should have some common features with melamine. Although melamine is a well-known compound, the assignment of its IR absorption bands was only recently completed with the aid of theoretical vibrational calculations.…”

Section: Resultsmentioning

confidence: 99%

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Polarization-Modulated Infrared Reflection Absorption Spectroscopic Studies of a Hydrogen-Bonding Network at the Air−Water Interface

et al. 1999

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The hydrogen-bonding network formed between a triaminotriazine amphiphile (2C 18 TAZ, 1) and complementary barbituric acid (BA, 2) at the air-water interface is investigated by polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS). The molecular structure and orientation of the 1:1 hydrogenbonding network at the air-water interface is revealed in this study. Without the addition of BA to the subphase, the NH 2 scissoring of 2C 18 TAZ appeared in the spectrum as a broad negative absorption band between 1660 and 1605 cm -1 , indicating its perpendicular orientation to the air-water interface. When BA was added to the subphase, the NH 2 scissoring absorption band from the triaminotriazine moiety disappeared due to the complementary hydrogen bonding of BA to the 2C 18 TAZ monolayer. The formation of the rigid 1:1 hydrogen-bonding network also resulted in the disappearance of one of the ring quadrant stretch absorption bands of the 2C 18 TAZ molecule. New bands which are attributed to the vibration of BA can be clearly seen. Particularly, the CdO stretch from BA shows up in the spectra as two negative absorption bands around 1700 cm -1 . The negative signature of these two bands suggests that the BA molecules are oriented in the hydrogen-bonding network with the C-2 carbonyl positioned vertically toward the air, and the C-4 and C-6 carbonyls directed into the water subphase. This is consistent with formation of an assembly which optimizes the use of complementary hydrogen bonding between two components. Furthermore, the effect of competitive polar organic solvents in subphase, such as DMSO, on the hydrogen-bonding network has also been observed in this study. Compared to the previous IRRAS studies on the similar monolayers, the sensitivity of PM-IRRAS is obviously improved. PM-IRRAS will likely become a powerful analytical technique for the characterization of molecular structure and orientation of Langmuir monolayers at the air-water interface.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Polarization-Modulated Infrared Reflection Absorption Spectroscopic Studies of a Hydrogen-Bonding Network at the Air−Water Interface

et al. 1999

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“…These can be divided into two parts: 21 vibrations are associated with the three NH 2 groups of melem, which is comparable to the situation found for melamine with its three amino groups. 55,56 Each NH 2 group has six vibrational modes: the stretching vibrations ν as -NH 2 and ν s NH 2 , the bending and rocking vibrations δNH 2 and FNH 2 which are in-plane, as well as the out-of-plane twisting and wagging vibrations τNH 2 and ωNH 2 . The remaining 39 modes are skeletal vibrations belonging to the C 6 N 7 nucleus which are found in trichloro-tri-s-triazine, too.…”

Section: Study Of Melem (258-triamino-tri-s-triazine)mentioning

confidence: 99%

Melem (2,5,8-Triamino-tri-s-triazine), an Important Intermediate during Condensation of Melamine Rings to Graphitic Carbon Nitride: Synthesis, Structure Determination by X-ray Powder Diffractometry, Solid-State NMR, and Theoretical Studies

et al. 2003

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Single-phase melem (2,5,8-triamino-tri-s-triazine) C6N7(NH2)3 was obtained as a crystalline powder by thermal treatment of different less condensed C-N-H compounds (e.g., melamine C3N3(NH2)3, dicyandiamide H4C2N4, ammonium dicyanamide NH4[N(CN)2], or cyanamide H2CN2, respectively) at temperatures up to 450°C in sealed glass ampules. The crystal structure was determined ab initio by X-ray powder diffractometry (Cu KR1: P21/c (No. 14), a ) 739.92(1) pm, b ) 865.28(3) pm, c ) 1338.16(4) pm, ) 99.912(2)°, and Z ) 4). In the solid, melem consists of nearly planar C6N7(NH2)3 molecules which are arranged into parallel layers with an interplanar distance of 327 pm. Detailed 13 C and 15 N MAS NMR investigations were performed. The presence of the triamino form instead of other possible tautomers was confirmed by a CPPI (cross-polarization combined with polarization inversion) experiment. Furthermore, the compound was characterized using mass spectrometry, vibrational (IR, Raman), and photoluminescence spectroscopy. The structural and vibrational properties of molecular melem were theoretically studied on both the B3LYP and the MP2 level. A structural optimization in the extended state was performed employing density functional methods utilizing LDA and GGA. A good agreement was found between the observed and calculated structural parameters and also for the vibrational frequencies of melem. According to temperature-dependent X-ray powder diffractometry investigations above 560°C, melem transforms into a graphite-like C-N material.Melamine (2,4,6-triamino-s-triazine), C 3 N 3 (NH 2 ) 3 1a, represents an important starting material for several industrial applications, for example, the syntheses of melamine-formaldehyde resins or of fireproof materials. 1,2 Furthermore, it is used for the architecture of supramolecular structures, for example, assemblies built up by cyanuric acid C 3 N 3 (OH) 3 1b or melamine derivatives. [3][4][5] In the past few years, another interest arose in melamine as well as in other compounds, C 3 N 3 X 3 1, containing s-triazine (cyanuric) rings C 3 N 3 , for example, cyanuric chloride C 3 N 3 Cl 3 1c [6][7][8][9][10] or cyanuric azide C 3 N 3 (N 3 ) 3 1d. 11 These are considered to be suitable molecular precursor compounds for the synthesis of graphitic forms of carbon nitride (g-C 3 N 4 ). 6,[12][13][14] In most of the postulated structures of g-C 3 N 4 , s-triazine ring systems are linked through trigonal N atoms forming extended 2D sheets 2 (Scheme 1).Recently, another possible building block for g-C 3 N 4 was taken into account (Scheme 2): tri-s-triazine rings C 6 N 7 which are cross-linked by trigonal N atoms 3. [15][16][17] The possible condensation of three s-triazine rings and the existence of a "cyameluric nucleus" C 6 N 7 4 was first postulated by Pauling † Ludwig-Maximilians-Universität München.

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“…Wang et al used a related scheme to assign analogous peaks in the IR and Raman spectra of melamine (C 3 N 3 (NH 2 ) 3 ), although significant contributions from -NH 2 torsional components were also suggested to be associated with the vibrational modes throughout this region. 101 The results of detailed IR and Raman studies of melamine are summarized by Mircescu et al…”

mentioning

confidence: 99%

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

Miller

Sobrido

Suter

et al. 2017

Phys. Chem. Chem. Phys.

370

351

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IR spectroscopy and theoretical vibrational calculation of the melamine molecule

Cited by 89 publications

References 8 publications

Polarization-Modulated Infrared Reflection Absorption Spectroscopic Studies of a Hydrogen-Bonding Network at the Air−Water Interface

Polarization-Modulated Infrared Reflection Absorption Spectroscopic Studies of a Hydrogen-Bonding Network at the Air−Water Interface

Melem (2,5,8-Triamino-tri-s-triazine), an Important Intermediate during Condensation of Melamine Rings to Graphitic Carbon Nitride: Synthesis, Structure Determination by X-ray Powder Diffractometry, Solid-State NMR, and Theoretical Studies

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

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