3156 J. Phys. Chem. A, Vol. 103, No. 17, 1999
Kozankiewicz et al.
Preparation of Di-2-naphthalenylmethanone. Di-2-naphtha-
lenylmethanone was prepared by the method of Olah et al.7
Piperidine (10 mL, 0.10 mol) was added dropwise to a solution
of ethyl chloroformate (5 mL, 0.05 mol) in diethyl ether (25
mL) at -78 °C under argon. The resulting solution was stirred
at ambient temperature for an hour and refluxed for another
hour. The reaction was quenched by addition of water. The
organic layer was washed with water, dried over sodium sulfate,
the solvent removed under vacuum, and the residue distilled
under vacuum to yield N-carboethoxypiperdine (5.8 g, 0.037
mol, 71% yield). IR (NaCl plates, neat) νmax: 2981, 2936, 2855,
water layer was extracted with pentane, and the combined
organic layers washed with brine, dried over MgSO4, and
concentrated under vacuum. The resulting red solid was
recrystallized two times from pentane; mp (uncorrected) 123-
1
124 °C. IR (KBr) νmax: 2021, 1625, 1595 cm-1. H NMR
(CDCl3, 200 MHz): δ 8.0-7.5 (m, 14H) ppm. 13C NMR
(CDCl3, 50 MHz): δ 133.9, 131.8, 128.9, 128.4, 127.8, 127.3,
127.0, 126.7, 125.7, 123.7, 123.4 ppm.
B. Experimental Setup. The 2,2-dinaphthylcarbene (22-
DNC) sample was obtained “in situ” by the photolysis of the
2,2-dinaphthyldiazomethane precursor dispersed in a Shpolskii
matrix of n-hexane or n-heptane at 5 K. The 366 nm line,
isolated by appropriate filters from the spectrum of a mercury
lamp, was used during this procedure. Before being inserted
into the liquid helium cryostat, all samples were degassed by
the “freeze-pump-thaw” technique. Samples of 22-DNC were
annealed overnight, when the cryostat was warmed slowly to
approximately 100 K, and subsequently cooled back the next
day to the temperature of boiling liquid helium.
1
1698, 1432 cm-1. H NMR (CDCl3, 200 MHz): δ 4.05 (q, 7
Hz, 2H, 3.40 (m, 4H), 1.5 (m, 6H), 1.20 (t, 7 Hz, 3H) ppm.
MS (m/e relative intensity): 157 (M+, 10), 156 (100), 128 (40),
84 (84). High-resolution mass calculated for C8H15NO2: 157.1103.
Found 157.1075.
A solution of N-carboethoxypiperidine (1.0 g, 0.073 mmol)
in diethyl ether (15 mL) was added to a dispersion of 2-lithium
naphthalene in diethyl ether at 0 °C under argon. This mixture
was stirred for half an hour at room temperature and then
refluxed for an hour. The reaction was quenched by addition
of 10% aqueous HCl (20 mL), and ethyl acetate (50 mL) was
added. The organic layer was washed with saturated sodium
bicarbonate solution and brine solution and dried over MgSO4
and the solvent removed under vacuum to give an off-white
solid (2 g). The resulting solid was recrystallized from an ethyl
acetate-hexane mixture to yield colorless plates of di-2-
naphthalenylmethanone (1.1 g, 4 mmol, 54% yield) and a mother
liquor that contained a mixture of di-2-naphthalenylmethanone
and some unreacted 2-bromonaphthalene (0.88 g).
The fluorescence and fluorescence excitation spectra (in
Warsaw) were measured using two different experimental
techniques. In the photon-counting configuration the samples
were excited either with the 366 nm line isolated from the
spectrum of a HBO200 mercury lamp or with the light emitted
by a Coherent 700 dye laser pumped by a mode-locked Coherent
Antares 76 Nd:YAG laser. In the latter case the laser was
scanned within the lasing frequency range of rhodamine 6G
dye, between 570 and 600 nm. Emission spectra were observed
at the right angle using a 0.25 m Jarrel-Ash monochromator
and an EMI 9659 photomultiplier, cooled to -20 °C and
operating in the photon-counting mode. A LightScan PC card
was used as the pulse-counting electronics and as the master
clock of the experiment. In the photon-sampling configuration
the excitation source was a Lambda Physik FL 1001 dye laser
pumped by an LPX 100 excimer laser. Coumarin 153 was the
lasing dye for the spectral range 530-600 nm and rhodamine
B for the range 595-640 nm. Fluorescence light was detected
with the aid of an EMI 9659 photomultiplier and a Stanford
Research SR250 boxcar averager connected to a previously
mentioned PC card.
The 2-lithium naphthalene was prepared by adding butyl-
lithium to an ether solution of 2-bromonaphthalene at ambient
temperature. The solution was stirred for 15 min and then
refluxed for half an hour; mp 157-8 °C (lit.8 125 °C). IR
1
(CHCl3)νmax: 1654, 1627, 1288 cm-1. H NMR (CDCl3, 200
MHz): δ 8.33 (s, 2H), 8.0 (s, 4H), 7.9 (m, 4H), 7.60 (d of quint,
2 and 7 Hz, 4H) ppm. 13C NMR (CDCl3, 75 MHz): δ 196.7
(CdO), 135.2 135,1 132.3, 131.8 129.4, 128.3, 128.2, 127.8,
126.8, 125.9 ppm. MS (m/e, relative intensity): 282 (M+, 81),
254 (30), 155 (100), 127 (89). Mass calculated for C21H14O:
282.1045. Found: 282.1048.
Fluorescence decays were measured using the “time-cor-
related” single-photon-counting technique. The samples were
excited in this case by the previously mentioned Coherent laser
system, which provided light pulses with about a 20 ps pulse
width and a 3.8 MHz repetition rate. Start and stop signals were
detected by an avalanche photodiode and a Hamamatsu R28090-
07 microchannel plate photomultiplier, respectively. A Tennelec
TC 454 quad constant fraction discriminator, a TC 864 time-
to-amplitude converter, and a Nucleus PCA-II multichannel
analyzer card were used. The estimated time resolution of this
setup was about 50 ps.
Preparation of (Di-2-naphthalenylmethane)hydrazide-4-me-
thylbenzenesulfonic Acid. Di-2-naphthalenylmethanone (1.11 g,
3.9 mol) and tosylhydrazone (0.74 g, 3.9 mol) were dissolved
in toluene and refluxed under argon overnight. The solvent was
removed under vacuum, and the resulting solid was recrystal-
lized from ethanol to yield colorless needles of (2,2-naphtha-
lenylmethane)hydrazide-4-methylbenzenesulfonic acid (1.41 g,
3.1 mole, 80% yield); mp 188-190 °C. IR (KBr) νmax: 3289,
1387, 1166 cm-1. 1H NMR (CDCl3, 200 MHz): δ 8.1-7.8 (m,
8H), 7.7-7.6 (m, 5H), 7.5-7.3 (m, 5H), 7.22 (dd, 8.5 and 1.6
Hz, 1H), 2.45 (s, 3H, -CH3) ppm. 13C NMR (CDCl3, 75
MHz): δ 154.4, 144.2, 135.6, 134.1, 134.0, 133.7, 133.3, 132.7,
130.0, 129.7, 129.0, 128.4, 128.4, 128.1, 128.1, 128.0, 127.7,
127.6, 127.3, 127.1, 126.4, 125.1, 123.8 ppm. MS (m/e, relative
intensity): 450 (M+, 81), 254 (30), 155 (100), 127 (89). Mass
calculated for C28H22N2O2S: 450.14036. Found: 450.13824.
The optical hole-burning setup (of the Bordeaux Laboratory)
used a single-mode dye laser Coherent CR 699-21 with 1-3
MHz frequency resolution and 30 GHz scan width. The lasing
dye was rhodamine 6G. The laser light was stabilized with the
aid of an electrooptic modulator Conoptics Lass-II. Holes were
burned with light intensity between 0.1 and 0.01 mW/cm2 over
a burning time between 100 and 500 s. The monitoring intensity
was about 10 times weaker than that when burning holes. The
fluorescence light emitted from the sample was collected by an
achromatic lens and focused on the slit of a small monochro-
mator (with spectral resolution of a few nanometers). A
monochromator was used to select the main vibronic line
separated by 1353 cm-1 from the 0,0 origin of the fluorescence.
Preparation of Di-2-naphthyldiazomethane. Di-2-naphthyl-
diazomethane was prepared by following a method by Jonczyk
et al.9 (Di-2-naphthalenylmethane)hydrazide-4-methylbenzene-
sulfonic acid was dissolved in dioxane (40 mL) and sodium
hydroxide (2 mL, 50% in water) added to the solution. The
reaction mixture was stirred and heated at 85 °C for an hour.
The resulting solution was cooled to room temperature. The