Initial Green

The precise choice of compound for the phosphor depends on a complex interplay of symmetry, interatomic spacing, stabiUty, etc in the crystal stmcture. The initial green emitting phosphor was the aluminate CeQ gyTbQ 23MgAl22022- More recently the choice has been a (LaQ 4CeQ 45TbQ 25)P04 compound and in addition a borate, (Ce,Gd,Tb)MgB 02Q, is also now used. 

The Lewis acid is important for polymerization. Surprisingly, the present author did not find evidence for or against the aryl cation (Ar+) as a polymerization initiator. Green and Stark (1981) briefly reviewed the photopolymerization of epoxides. 

The unicity of the GFP family is better appreciated when knowing that all red GFPs mature from a green precursor carrying the same chromophore as AvGFP, to which they can eventually revert back [33, 41], while initially green GFPs can evolve in different ways toward red emission [20, 42-44], Similarly, many chromoproteins can be turned fluorescent at alkaline pHs [45], upon photoactivation [46], or... 

The two-particle Green function G has the same poles as the initial Green function G and satisfies the BS-like equation... 

In an apparatus set up for steam distillation and containing a rapidly stirred solution of 5.0 gm (0.023 mole) of jV-benzoylphenylhydroxylamine (N-phenylbenzohydroxamic acid) in 100 ml of a 1 1 solution of ethanol-acetic acid, cooled to —20°C, is added 11.5 gm (0.024 mole based on 94% purity) of lead tetraacetate in one portion. After approximately 10 sec (when the initial green color just begins to darken), 100 ml of water is added and the brown or black mixture is rapidly subjected to steam distillation. The distillate is collected in a receiver filled with chopped ice. The product is isolated by filtration of the distillate. Finally, it is dried by pressing dry between filter papers to yield 1.4-2.0 gm (56-80%), m.p. 66°-68°C. 

Triturate 4 times with 50 cm3 portions of Et20 50 cm3 EtjO, stir 1 h, decant, repeat 50 cm3 Et20, stir 0.5 h, decant Initial green gelatinous solid, stir 25 cm3 Et,0, stir 15 cm3 Et20, stir overnight 10 cm3 EOF, stir 1.5 h... 

Observations The color of the reaction solution is initially green, turns to brown, and then to black in 5 min at 10°C, the time needed for the color to change to black is longer (about 11 min). 

Initial green ball depth Fuel consumption... 

TetramethyIisoindole (6 g, 34.6 mmole) and cobalt powder (30 g, 0.51 mole) are mixed and loaded into a Carius tube (4 X 35 cm volume about 450 mL). After it is evacuated and sealed, the tube is placed in a shielded oven preheated to 390° and heated at this temperature for 4 hours. After the tube is cooled, the dark-blue (or black) powder is placed in a Soxhlet extractor and extracted with pentane (300 mL) until a red-brown impurity is removed (about 24 hours). The pentane is replaced by toluene (300 mL), and extraction is continued until the extract (initially green) is colorless (about 8 hr). Finally, pyridine (300 mL) is used to extract (Soxhlet extractor) the porphine, which requires about 10 hours. The pyridine solution is concentrated to 20 mL, and 100 mL of hexane is added. The precipitate is collected, washed with hexane, and dried overnight in vacuum at 60°, to give [octamethyltetrabenzoporphinato-(2-)] cobalt(II). Yield 2-3 g (35-55%). Anal. Calcd. for C44H36N4Co C, 77.79 H, 530 N, 8.24. Found C, 77.87 H, 5.40 N, 8.48. 

The initial green density of the Si compact is, therefore, tailored to be just that necessary to give the theoretical density SisN4 after the reaction is complete. 

Diphenylamine 1 (338 mg, 2.00 mmol) in an evacuated 250-mL flask at 0°C was exposed to N02 gas (370 mg, 8.0 mmol) that was slowly added from a 300-mL funnel through an adjusted stopcock over 4-6 h. After 12 h the gases of reaction were condensed to a cold trap at 77 K and the product evacuated for 2 h at 5x10 4 Torr. Colorless 2 (309 mg, 92%), mp 168-173°C dec., was obtained after sublimation of the initially green product at 5 x 10"4 Torr. 

During reflux, the initial green solution changes to brown and finally orange. It is filtered to remove traces of undissolved material and potassium chloride (12.6 g) added to the filtrate to precipitate the crude product. The solution and solid are then heated at the boil to give a deep-red solution which on cooling to room temperature yields beautiful, red platelike crystals. These are filtered off, washed with ice-cold 10% aqueous acetone (2X5 mL) and acetone (30 mL), and air dried. The yield is 1.15 g (80%). The product may be recrystallized from boiling water ( 2.8 mL/g) and then air dried. 

The tungsten analogs are also known e.g., v m W04 in 12MHC1 is reduced, salts of the blue ion WOCl3 can b< obtained, i When MoCls is dissolved in concentrated I A and solid NaOH is added, the initial green solutions of M0OCI2- become darker and almost opaque... 

For the dehydrogenation, dissolve 10 g. of the adduct in 150 ml. of 6 per cent, potassium hydroxide solution (prepared by dissolving 7 5 g. of potasfflum droxide pellets in 142 5 g. of 95 per cent, ethanol) in a 250 ml. three-necked flask equipped with a reflux condenser and gas inlet tube. Bubble a current of air through the solution for 24 hours the initial green colour changes to yellow and much heat is generated. Filter the yeUow solid at the pump, wash successively with 50 ml. of water, 25 ml. of alcohol and 10 ml. of ether, and dry in the air. The yield of 2 3-dimethylanthraquinone, m.p. 209-210°, is 7-5 g. 

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