Triplet-State Electron Spin Resonance of Chlorophyll a and b Molecules and Complexes in PMMA and MTHF. I: Experimental Determination of Fine-Structure and Rate Constants

The triplet state zero-field splittings and the rate constants for the population and depopulation of the triplet spin sublevels have been investigated for chlorophyll a and chlorophyll b in polymethylmethacrylate (PMMA) and methyltetrahydrofurane (MTHF) as a function of the concentration. In PMMA both chlorophyll a and chlorophyll b yielded only one ESR spectrum in the entire range of concentration which could be covered (1.5 × 10-5 - 1 × 10-3 mole/1). In MTHF the results were more complicated. At low concentrations (up to 103 mole/1) only one spectrum was observed, at higher concentrations additional spectra were detectable (all together two for chlorophyll a and five for chlorophyll b at 10-1 mole/1). The assignment of these spectra was facilitated by observing the "triplet resonance-field identity" which connects the resonancefield strengths for the canonical orientations of one particular species. Furthermore, the rate constants for some of these species could be determined.

Download Full-text

Determination of the Rate Constants of the Intersystem Crossing Processes to the Individual Zero‐Field Levels of the Lowest Triplet State

The Journal of Chemical Physics ◽

10.1063/1.1671514 ◽

1969 ◽

Vol 50 (7) ◽

pp. 3113-3114 ◽

Cited By ~ 12

Author(s):

M. A. El‐Sayed ◽

L. Hall

Keyword(s):

Triplet State ◽

Rate Constants ◽

Intersystem Crossing ◽

Zero Field ◽

The Individual

Download Full-text

ANALISIS KANDUNGAN KLOROFIL PADA BERBAGAI POSISI DAUN DAN ANAK DAUN AREN (Arrenga pinnata)

CHEMISTRY PROGRESS ◽

10.35799/cp.12.2.2019.27925 ◽

2020 ◽

Vol 12 (2) ◽

Author(s):

Olivia P. G. Lawendatu ◽

Julius Pontoh ◽

Vanda Kamu

Keyword(s):

Chlorophyll Content ◽

Chlorophyll A ◽

Palm Tree ◽

Plant Canopy ◽

Chlorophyll B ◽

Chlorophyll A And B ◽

Palm Leaf

ABSTRAKTelah dilakukan penelitian tentang analisis kandungan klorofil dari berbagai posisi daun dan anak daun dari tanaman aren. Daun aren diambil pada posisi atas, tengah, dan bawah dari tajuk tanaman. Sampel anak daun dibagi 3 posisi yaitu atas, tengah, dan bawah. Ekstraksi dilakukan dengan methanol dan penetuan klorofil pada daun dilakukan dengan spektofotometer pada panjang gelombang 665 nm dan 652 nm untuk masing-masing klorofil a dan klorofil b. Kandungan klorofil a dan b yang terdapat pada sampel daun aren yang dihitung berdasarkan 3 unit satuan µg/mL, mg/g dan µmol/m2. Kandungan klorofil a dan b pada sampel pohon aren tertinggi terletak pada posisi kiri daun, pada posisi daun terletak pada daun atas, pada posisi anak daun terletak pada posisi ujung anak daun. Ratio kandungan klorofil pada sampel daun aren berkisar 1,30-6,72. ABSTRACTHas conducted research on the analysis of chlorophyll content from various positions of leaves and leaves of palm plants. Leaves are taken in the top, middle and bottom positions of the plant canopy. Samples of leaflets were divided into 3 positions namely top, middle and bottom. Extraction was carried out with methanol and the determination of chlorophyll in the leaves was carried out by spectrophotometer at wavelengths of 665 nm and 652 nm for chlorophyll a and chlorophyll b, respectively. The chlorophyll and b content in palm leaf samples are calculated based on 3 units of μg/mL, mg/g, and µmol/m2. The content of chlorophyll a and b in the highest palm tree sample is located in the left position of the leaf, the position of the leaf is placed on the top of the leaf, the position of the leaflets is placed in the tip of the leaflets. The ratio of chlorophyll content in sugar palm leaf samples in the setting is 1.30-6.72.

Download Full-text

Triplet-State Electron Spin Resonance of Chlorophyll a and b Molecules and Complexes in PMMA and MTHF. II: Interpretation of the Experimental Results

Zeitschrift für Naturforschung A ◽

10.1515/zna-1978-0117 ◽

1978 ◽

Vol 33 (1) ◽

pp. 94-97 ◽

Cited By ~ 18

Author(s):

W. Hagele ◽

D. Schmid ◽

H. C. Wolf

Keyword(s):

Experimental Data ◽

Chlorophyll A ◽

Energy Exchange ◽

Photosynthetic Bacteria ◽

Esr Spectra ◽

Experimental Results ◽

Chlorophyll B ◽

Triplet Energy ◽

Spin Resonance ◽

Chlorophyll A And B

ESR spectra of various triplet species, obtained with solutions of chlorophyll a or chlorophyll b in PMMA or MTHF, are attributed to isolated chlorophyll molecules, to chlorophyll-solvent complexes and to dimeric structures. The structure of the proposed dimer is determined using the experimental results for the fine-structure and the rate constants and by assuming an incoherent triplet-energy exchange. Based on this model the structure of the reaction center in photosynthetic bacteria was also reevaluated using the experimental data which were published by various authors.

Download Full-text

A study of the low-lying singlet and triplet electronic states of chlorophyll A and B

Journal of the Serbian Chemical Society ◽

10.2298/jsc130806096e ◽

2013 ◽

Vol 78 (11) ◽

pp. 1775-1787 ◽

Cited By ~ 5

Author(s):

Mihajlo Etinski ◽

Milena Petkovic ◽

Miroslav Ristic

Keyword(s):

Chlorophyll A ◽

Density Functional ◽

Chlorophyll B ◽

Fluorescence Lifetimes ◽

Functional Theory ◽

Chlorophyll A And B ◽

Vertical Ionization Potentials ◽

Density Functional Theory Optimization ◽

Triplet Formation ◽

Good Agreement

Chlorophylls have been extensively investigated both experimentally and theoretically owing to the fact that they are essential for photosynthesis. We have studied two forms of chlorophyll, chlorophyll a and chlorophyll b, by means of density functional theory. Optimization of S0, S1 and T1 states was performed with the B3-LYP functional. The computed fluorescence lifetimes show good agreement with the available experimental data. The electronic adiabatic energies of S1 and T1 states are 2.09/2.12 and 1.19/1.29 eV for chlorophyll a and chlorophyll b respectively. We discussed the implications of this results on the triplet formation. Also, the calculated vertical ionization potentials shows good agreement with the experimental results.

Download Full-text

Photophysics of the lowest triplet state in 2-benzoylpyridine crystals. II. Optically detected e. p. r. in zero and high magnetic fields

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1979.0159 ◽

1979 ◽

Vol 369 (1737) ◽

pp. 187-206 ◽

Cited By ~ 4

Keyword(s):

Triplet State ◽

Rate Constants ◽

Radiative Decay ◽

Dynamic Properties ◽

Deep Trap ◽

Lattice Relaxation ◽

Spin Lattice Relaxation ◽

Zero Field ◽

Spin Lattice ◽

Optically Detected

Optically detected zero-field resonance has been used to characterize the intrinsic and deep trap 3 nπ * states in single crystals of 2-benzoylpyridine at 4.2 K. The dynamic properties of these states were studied by means of time-resolved modulated phosphorescence (t. r. m. p.) and estimates for the rate constants for depopulation and spin-lattice relaxation of the magnetic sub-levels obtained by computer simulation. For all species, depopulation from ז z dominates, having rates of order 100 s -1 , but the ז x and ז y sub-states have substantial radiative activity. The orientations of the fine-structure tensors of the magnetic species were determined from high-field e. p. r. spectra. Assuming that z is parallel to C = O, excitation causes the C = O direction to change by 8 ± 2° for the intrinsic species and by an in-significant amount for the deep trap. These spectra also demonstrated that the intrinsic triplet state is mobile. This species is believed to be a polaron with slow intersite hopping rate. A maximum energy transfer rate of 10 4 -10 5 s -1 was found for transfer between translationally inequivalent sites symmetry-related by twofold rotation about the crystal b -axis. Rate estimates for transfer to the other two translationally inequivalent sites established the two dimensional nature of the polaron. The sign and shape of the zero-field resonances for the intrinsic species were found to depend on whether excitation was through S 1 or T 1 . From the parameters required to simulate the corresponding t. r. m. p. signals it is inferred that the changes are largely due to differences in the rate constants for non-radiative decay. The deep trap was shown to have an orientation and magnetic properties similar to those of the intrinsic species, and is believed to be a physical defect. It has radiative activity from the ז x sub-level which is significantly less than for the intrinsic species. Spin-lattice relaxation is fast for the mobile intrinsic species ( ca . 10 4 s -1 ) compared with the deep trap rate ( ca . 50 4 s -1 ). For the intrinsic species a field dependence for spin-lattice relaxation is apparent.

Download Full-text

Analisis Kandungan Klorofil Pada Anak Daun Tanaman Kelapa (Analysis of Chlorophyll Content in Children Leaves of Coconut Plants)

JURNAL BIOS LOGOS ◽

10.35799/jbl.9.2.2019.24372 ◽

2019 ◽

Vol 9 (2) ◽

pp. 76

Author(s):

Muhammad Tawary ◽

Julius Pontoh ◽

Lydia Momuat

Keyword(s):

Chlorophyll Content ◽

Chlorophyll A ◽

Economic Value ◽

Economic Benefits ◽

Chlorophyll B ◽

Solvent Extraction Method ◽

Chlorophyll A And B ◽

The Right ◽

Almost All ◽

Chlorophyll A Content

Analisis Kandungan Klorofil Pada Anak Daun Tanaman Kelapa (Analysis of Chlorophyll Content in Children Leaves of Coconut Plants) Muhammad Tawary1*), Julius Pontoh1), Lydia I.Momuat1)1)Jurusan Kimia, FMIPA UNSRAT Manado*Email korespondensi: [email protected] Diterima 7 Juli 2019, diterima untuk dipublikasi 10 Agustus 2019 Abstrak Tanaman kelapa banyak dibudidayakan sebagai tanaman pertanian. Tanaman kelapa memiliki nilai ekonomi yang tinggi karena hampir semua bagian tanaman kelapa memiliki manfaat ekonomis. Penelitian bertujuan untuk mengembangkan metode analisis klorofil pada daun dan menentukan bagian anak daun yang memiliki kandungan klorofil tertinggi. Analisis kandungan klorofil dilakukan dengan metode ektraksi pelarut yang absorbansinya dibaca pada spektrofotometer UV-Vis. Kandungan klorofil a dalam daun bervariasi pada setiap bagian anak daun tanaman kelapa. Kandungan klorofil a pada posisi tengah anak daun kelapa (763.19 µmol/m2) dan kandungan klorofil b (196.22 µmol/m2). Kandungan klorofil a dan b pada setiap bagian anak daun dan posisi kanan dan kiri anak daun memiliki nilai yang relatif sama.Kata kunci: Kelapa, klorofil a, klorofil b Abstract Many coconut plants are cultivated as agricultural crops. Coconut plants have high economic value because almost all parts of coconut plants have economic benefits. The study aims to develop a method of chlorophyll analysis on leaves and determine the part of leaflets which have the highest chlorophyll content. Analysis of chlorophyll content was carried out by a solvent extraction method in which the absorbance was read in a UV-Vis spectrophotometer. The content of chlorophyll a in leaves varies with each part of the leaves of the coconut plant. Chlorophyll a content in the middle position of coconut leaf child (763.19 µmol / m2) and chlorophyll b content (196.22 µmol / m2). The content of chlorophyll a and b in each part of the leaf child and the right and left positions of the leaves have relatively the same value.Keywords: Coconut, Chlorophyll a, Chlorophyll b

Download Full-text

Variations of Chlorophyll Content at Abies alba and Nepeta pannonica Species According to Phenophase and Harvesting Area

Cercetari Agronomice in Moldova ◽

10.2478/cerce-2019-0008 ◽

2019 ◽

Vol 52 (1) ◽

pp. 74-78

Author(s):

S. Buhăianu ◽

Doina Carmen Jităreanu

Keyword(s):

Chlorophyll Content ◽

Chlorophyll A ◽

Photosynthetic Pigments ◽

Photosynthetic Activity ◽

Abies Alba ◽

Chlorophyll B ◽

Green Color ◽

Yellow Coloration ◽

Chlorophyll A And B ◽

Chlorophyll A Content

Abstract Chlorophylls from plants are photosynthetic pigments. Their quantity offers valuable informations about photosynthetic activity, growing and developing of plants. Photosynthetic pigments decrease quantitatively during senescence process or in stress conditions. The present study has been realized in laboratory conditions with material harvested from spontaneous flora. The purpose of this research was the investigation of variations of chlorophyll content from samples of biological material collected from Nepeta pannonica L. and Abies alba Mill. plants, from Câmpulung Moldovenesc and Cacica areas, Suceava county, Romania. The targeted phenophases were growth and flowering. There were realized acetonic extracts from samples for spectrophotometric determinations. Obtained data were processed to estabilish chlorophyll a and b content. There were observed that at Abies alba species, from both locations, the chlorophyll a content grew during flowering phenophase, while the chlorophyll b content had little variations. At Nepeta pannonica species, the chlorophyll a and b content decreased visibly during the flowering, due to stress. Leaves of plants from this species presented a intense green color in the growing phenophase, while during flowering phenophase they had a purple or yellow coloration. Obtained results revealed a different dynamics of chlorophyll content at studied species.

Download Full-text

The effect of drought stress and nitrogen fertilization on the active ingredient, chlorophyll A and B, and chlorophyll index of henna

Nexo Revista Científica ◽

10.5377/nexo.v33i02.10802 ◽

2020 ◽

Vol 33 (02) ◽

pp. 694-706

Author(s):

Hassan Sarhadi ◽

Jahanfar Daneshian ◽

Seyyed Alireza Valadabadi ◽

Hossein Heidary Sharafabad ◽

...

Keyword(s):

Drought Stress ◽

Chlorophyll A ◽

Active Ingredient ◽

Block Design ◽

N Fertilization ◽

Water Requirement ◽

Plant Water ◽

Chlorophyll B ◽

Chlorophyll A And B ◽

Chlorophyll Index

The response of active ingredient, chlorophyll a and b contents, and chlorophyll index of henna to different rates of N fertilization and drought stress was explored in a split-split-plot experiment based on a randomized complete block design with four replications in the research farm of Jiroft Branch, Islamic Azad University, Jiroft, Iran in the 2016-2017 growing season. In the current study, the main plot was assigned to drought stress at three levels (including irrigation to supply 100%, 75% or 50% of plant water requirement), the sub-plot was assigned to N fertilization at three rates (50, 100 or 150 kg ha-1 pure N), and the sub-sub-plot was assigned to ecotype at three levels (Bami, Bushehri, and Rudbari). The results showed that the effect of drought level was significant on active ingredient and chlorophyll index at the p < 0.01 level and on chlorophyll a, total chlorophyll, and chlorophyll a/b ratio at the p < 0.05 level. But, it could not influence chlorophyll b significantly. The effect of N fertilization was significant on most studied traits at the p< 0.01 level, but its effect was significant on the chlorophyll index at the p < 0.05 level and insignificant on dye and chlorophyll b. According to the results, it seems that the application of 100 kg ha-1 N and the irrigation to supply 75% of plant water requirement can contribute to having more fresh plants with the higher active ingredient and dye contents.

Download Full-text