Photocatalysis of chloroform decomposition by the hexachlororuthenate(IV) ion

Article abstract of DOI:10.1111/php.12005

Dissolved hexachlororuthenate(IV) effectively catalyzes the photodecomposition of chloroform to hydrogen chloride and phosgene under near-UV (λ > 345 nm) irradiation, whereby RuCl₆^2- is not itself photocatalytically active, but is photochemically transformed into a species that is active, possibly RuCl₅(CHCl₃)^-. Conversion to a photoactive species during irradiation is consistent with the acceleration of the decomposition rate during the early stages and with the apparent inverse dependence of the decomposition rate on the initial concentration of RuCl₆^2-. The displacement of Cl ^- by CHCl₃ in the coordination sphere to create the photoactive species is consistent with the retardation of photodecomposition by both Cl^- and H₂O. The much smaller photodecomposition rate in CDCl₃ suggests that C-H bond dissociation occurs during the primary photochemical event, which is also consistent with the presence of a CHCl₃ molecule in the first coordination sphere. In the presence of RuCl₆^2-, chloroform decomposes under near-UV irradiation to phosgene and hydrogen chloride. The photoactive species is suggested to be RuCl₅(CHCl₃) ^-.

Full text of DOI:10.1111/php.12005

Photochemistry and Photobiology, 2013, 89: 274–279
Photocatalysis of Chloroform Decomposition by the Hexachlororuthenate
(IV) Ion
Alissa M. Chan, Laura A. Peña, Rosa E. Segura, Ramya Auroprem, Brent M. Harvey, Caroline M. Brooke
and Patrick E. Hoggard*
Department of Chemistry, Santa Clara University, Santa Clara, CA
Received 8 August 2012, accepted 1 October 2012, DOI: 10.1111/php.12005
ABSTRACT
in which the trichloromethoxy radical is proposed to decompose
to COCl2 and Cl atoms (10), leaving the latter to abstract hydro-
gen from chloroform. The net reaction is the same in either case:
Dissolved hexachlororuthenate(IV) effectively catalyzes the
photodecomposition of chloroform to hydrogen chloride and
phosgene under near-UV (k > 345 nm) irradiation, whereby
2CHCl3 þ O2 ! 2COCl2 þ 2HCl
ð6Þ
2ꢀ
RuCl6 is not itself photocatalytically active, but is photo-
chemically transformed into a species that is active, possibly
RuCl5(CHCl3)ꢀ. Conversion to a photoactive species during
irradiation is consistent with the acceleration of the decomposi-
tion rate during the early stages and with the apparent inverse
dependence of the decomposition rate on the initial concentra-
tion of RuCl62ꢀ. The displacement of Clꢀ by CHCl3 in the
coordination sphere to create the photoactive species is consis-
tent with the retardation of photodecomposition by both Clꢀ
and H2O. The much smaller photodecomposition rate in
CDCl3 suggests that C–H bond dissociation occurs during the
primary photochemical event, which is also consistent with the
presence of a CHCl3 molecule in the first coordination sphere.
In condensed phase, hydrogen abstraction by the CCl3O radi-
cal is presumed to be faster than unimolecular decomposition
(11), leading to the formation of trichloromethanol, whose
decomposition, Eq. (5), has a half-life of about 100 s in the gas
phase (12).
The existence of trichloromethanol as an intermediate makes
possible an additional side reaction leading to carbon tetrachloride:
CCl3OH þ 2HCl ! CCl4 þ fH3Oþ; Clꢀg
ð7Þ
Recent theoretical calculations have predicted that CCl3OH
will decompose more rapidly in the presence of hydrogen halides
(13). Reaction with a single HCl molecule to make CCl4 and H2O
is not energetically favorable (14), but protonation of the water by
a second HCl molecule greatly increases the driving force.
There are several ways the radical required for Eq. (1) can be
generated with the help of a chlorometallate catalyst. One very
direct way is by photodissociation of a chlorine atom, as is pre-
sumed to occur with FeCl4ꢀ (15,16):
INTRODUCTION
Several chlorometallate complexes have been found to catalyze
the photodecomposition of liquid chloroform (1–4), effectively
raising the threshold wavelength for decomposition from ca
260 nm for neat chloroform, in some cases to well above
400 nm (5). Although the mechanism of catalysis appears to
vary among the chlorometallate complexes, most of the mecha-
nisms have in common the production of a radical, leading to
the sequence of steps shown below.
hm
FeClꢀ4
FeClꢀ þ Clꢁ
ð8Þ
ƒ!
3
To complete the cycle, the iron must be reoxidized, from
which process more radicals may be generated. A second route
to radicals is the photoreduction of the solvent, which is thought
Rꢁ þ CHCl3 ! RH þ ꢁCCl3
ꢁCCl3 þ O2 ! CCl3OOꢁ
2CCl3OOꢁ ! 2CCl3Oꢁ þ O2
CCl3Oꢁ þ CHCl3 ! CCl3OH þ ꢁCCl3
CCl3OH ! HCl þ COCl2
ð1Þ
ð2Þ
ð3Þ
ð4Þ
ð5Þ
2ꢀ
to occur with OsCl6 as the catalyst (3):
OsCl26ꢀꢂ þ CHCl3 ! OsCl6ꢀ þ Clꢀ þ ꢁCHCl2
ð9Þ
As a consequence of the generation of dichloromethyl radicals,
termination products are expected to include C2H2Cl4 and
C2HCl5 when this mechanism is operative.
Another route to chloroform decomposition can arise from the
photooxidation of a counterion. This is more readily accom-
plished when the counterion is negatively charged; thus, chloro-
metallates would not normally be candidates for this mechanism.
A complex that does appear to catalyze chloroform decomposi-
tion in this way is [Ru(bpy)2Cl2]+, which, when excited, appar-
Equations (2)–(4) constitute a radical chain, for which C2Cl6 can
be expected to be the major termination product. This sequence
differs from that accepted for the gas-phase decomposition (6–9),
*Corresponding author email: phoggard@scu.edu (Patrick E. Hoggard)
© 2012 Wiley Periodicals, Inc.
Photochemistry and Photobiology © 2012 The American Society of Photobiology 0031-8655/13
ꢁ
ently oxidizes Clꢀ to Cl (17).
274

Photochemistry and Photobiology, 2013, 89 275
While these and other (1,4) mechanisms lead to photocata-
lyzed decomposition, the situation is often complicated by a
transformation of the original chlorometallate complex to another
species under irradiation (2–4,18), which can greatly obscure
mechanistic conclusions.
In this study, we examine the photodecomposition of chloro-
form catalyzed homogeneously by the hexachlororuthenate(IV)
ion, with a number of tests designed to unravel mechanistic
details.
Because of this, the analyses for both HCl and COCl2 (see below)
can be assumed to underestimate the total amount actually produced. To
this discrepancy may be added that from the evaporation of both sub-
stances from chloroform solutions.
Phosgene was measured by taking advantage of its condensation with
methanol, which was found to be complete within 2 min under the con-
ditions employed:
COCl2 þ MeOH ! ClCO(OMe) þ HCl
ð11Þ
After adding an aliquot of the photolysate to H2TPP and measuring the
absorbance change at 446 nm, a 50 lL portion of MeOH was injected
and, after 2 min, the absorbance was remeasured to find the amount of
HCl formed by the condensation. This was done likewise with the sec-
ond, smaller aliquot, and Eq. (11) was also applied to these data.
MATERIALS AND METHODS
Chloroform (J. T. Baker, ACS Grade) was washed seven times with an
equal volume of water to remove the ethanol stabilizer, the absence of
which was verified by GC-MS. Molecular sieves (5A; Sigma-Aldrich)
were added to remove water.
Attempts to prepare a tetraalkylammonium hexachlororuthenate(IV)
salt were unsuccessful because either no precipitate formed (e.g. with
Bu4N+) or, when precipitation did occur (e.g. with Hx4N+), it had a waxy
consistency that made isolation and purification impractical. Instead, the
hexachlororuthenate(IV) ion was solubilized in chloroform by first mix-
ing aqueous solutions of (NH4)2RuCl6 and Bu4NCl in an approximately
1:5 mole ratio, then extracting (Bu4N)2RuCl6 into an equal volume of
chloroform. The UV–Visible spectrum was not significantly different
from that of (NH4)2RuCl6 in water, and therefore extinction coefficients
from aqueous solution were used to estimate concentrations in chloro-
form.
UV–Visible spectra were recorded with a Cary 50 spectrophotometer.
GC-MS measurements were carried out with a Shimadzu QP-5000 instru-
ment with an Agilent DB624 column (30 m, 0.32 mm 9 1.8 lm cyano-
propylphenyl/dimethyl polysiloxane film). The oven start temperature
was 40°C and a 20°C minꢀ1 linear temperature gradient was applied to a
final temperature of 240°C. For all quantitative measurements, a 10:1
split ratio was applied to sample injections. Species were identified from
their mass spectra and peak areas were used to determine concentrations.
Before injection, 50 lL of ethanol, containing xylene as an internal stan-
dard, was mixed with 500 lL of the photolysate. The ethanol converted
phosgene to ethyl chloroformate; thus, this compound was taken as the
analytical standard for phosgene. Phosgene was readily identifiable in the
gas chromatogram when no ethanol was added, and its complete disap-
pearance and conversion to ethyl chloroformate was likewise readily
observable. Analyses had to be undertaken within a few hours to avoid
further condensation of ethyl chloroformate with ethanol to give diethyl
carbonate.
RESULTS AND DISCUSSION
Variation in product yield with time
Broadband irradiation (k > 345 nm) of chloroform containing
(Bu4N)2RuCl6 caused chloroform decomposition, generating HCl
and COCl2, as can be seen in Fig. 1. Although a 1:1 ratio of these
two products would be expected from Eq. (6), in fact considerably
more phosgene was produced. An induction period is evident,
after which the two products grow approximately linearly with
time, COCl2 about eight times as fast as HCl.
Chloroform photodecomposition was accompanied by signifi-
cant spectral changes, as shown in Fig. 2. Over a period of
20–30 min, a substance with an intense UV absorption peak at
274 nm accumulated in solution. In relatively dilute solutions, this
was accompanied by a general decrease in intensity in the visible
spectrum; however, with more concentrated solutions
Photodecomposition was generally carried out on 2.0 mL portions of
chloroform containing a known concentration of (Bu4N)2RuCl6 in a fused
silica spectrophotometer cuvette with stirring. The cuvette was loosely
capped, leaving approximately 2 mL of head space. Light from an Oriel
Q Series housing with a 100-W mercury lamp was passed through a
345 nm highpass filter and focused on the sample. Balloons were some-
times used to control the composition of the atmosphere above the reac-
tion. A fan was used to maintain the temperature in the cuvette at
22 2°C.
HCl production was measured by taking aliquots of the photolysate
(between 20 and 100 lL, after diluting with chloroform when necessary)
and adding them to 3 mL portions of tetraphenylporphyrin (H2TPP;
Frontier Scientific) in CHCl3. The absorbance change at 446 nm and
extinction coefficients for H2TPP and H4TPP2+ (19,20) were used to
determine the concentration of [H4TPP2+] formed through the protonation
of the remaining porphyrin nitrogens:
2HCl þ H2TPP ꢀ fH4TPP2þ; 2Clꢀg
ð10Þ
While the intermediate H3TPP+ species can be neglected (21), Eq. (10) is
not completely stoichiometric at the typical concentrations of HCl and
H2TPP used, and an approximation to the true value can, in principle, be
made by measuring the absorbance of a second solution with a smaller
volume of the analyte solution (22). It was found, however, that the mag-
nitude of the corrections made was smaller than the variability of
repeated measurements. Therefore, corrections were not made and each
analyte dilution was treated as an independent measurement.
Figure 1. HCl and COCl2 produced during the irradiation (k > 345 nm)
of a 2 9 10ꢀ4 M solution of (Bu4N)2RuCl6 in CHCl3. Solid lines are fits
as described in text. The yield of COCl2 at 36 min corresponds to
approximately 60 equivalents, based on Ru.

276 Alissa M. Chan et al.
d½COCl2ꢃ
dt
¼ b2fB
ð16Þ
While none of these can be integrated in closed form, they are
readily integrated numerically, by computing incremental concen-
tration changes over small time intervals. The solid lines in Fig. 1
were obtained by this procedure, optimizing the fit to the experi-
mental data. In general terms, the induction period arises when
the inactive complex A is converted to the catalytically active B,
whereby the extinction coefficient of A is considerably higher
than that of B. This would mean that even after a relatively large
fraction of A had been converted to B, A could still be absorbing
more light than B, with the result that HCl and COCl2 would still
be forming at a relatively low rate. Only later, when there was
very little A remaining, would B be absorbing more light than A.
At this point, the rate of decomposition would be approaching a
constant value. Given the decrease in solution absorbance during
irradiation at wavelengths above 345 nm, this corresponds quali-
tatively to what was observed.
Control experiments
Figure 2. Spectral changes at 3 min intervals during the irradiation
(k > 345 nm) of 2 9 10ꢀ4 M (Bu4N)2RuCl6 in CHCl3.
Irradiation under identical conditions of neat chloroform yielded
no detectable quantity of HCl or COCl2, nor were these products
obtained from chloroform solutions of (Bu4N)2RuCl6 kept in the
dark for 6 h.
(~5 9 10ꢀ4M) approximate isosbestic points developed at about
380 and 480 nm, the absorbance decreasing between those two
wavelengths.
2ꢀ
Variation in product yield with RuCl6 concentration
The time scale for the spectral changes rather naturally gives
rise to the supposition that they are related to the observed
induction period for photodecomposition. In fact, a conceptually
(although not mathematically) simple model can account quite
well for the temporal development. Although the ruthenium spe-
ciation may be more complex, we assume for this purpose that a
reactant A is photochemically converted to B, and that only B
can catalyze the photodecomposition of chloroform. The rate of
conversion of A to B is taken to be proportional to the fraction
of light absorbed by A, fA, whereas the rate of formation of HCl
and COCl2 are likewise taken to be proportional to the fraction
of light absorbed by B, fB. These fractions are given by (23)
The rate of chloroform photodecomposition varied considerably
with the concentration of the RuCl62ꢀ, in a manner that might at
first seem peculiar. The yield of COCl2 from several experiments
2ꢀ
in which only the concentration of RuCl6 was changed are
shown in Fig. 3. Notable is a steep decline in yield above a
ruthenium concentration of about 1 x 10ꢀ5 M.
While this behavior appears to be that of an inhibitor rather
than a catalyst, in fact it fits well with the hypothesis presented
2ꢀ
above. When the concentration of RuCl6 (A) is high enough
that most of the photons capable of causing conversion to the
active ruthenium species (B) are absorbed, higher concentrations
do not increase the rate of conversion substantially, but a smaller
fraction of the absorbed photons go into the excitation of the
active ruthenium species, thus slowing the photodecomposition.
The solid line in Fig. 3 was achieved by a numerical fit of
Eqs. (12) through (16) to the experimental data.
ꢀ
ꢀ
ꢁ
ꢁ
eA½Aꢃ
½AꢃþeB½BꢃÞ
fA
¼
¼
1 ꢀ eꢀ2:303ðe
ð12Þ
ð13Þ
A
eA½Aꢃ þ eB½Bꢃ
eB½Bꢃ
½AꢃþeB½BꢃÞ
fB
1 ꢀ eꢀ2:303ðe
A
eA½Aꢃ þ eB½Bꢃ
Effect of ethanol, cyclohexane and water on the rate of
photodecomposition
Note that these equations are actually valid only for a specific
wavelength. The true fractions of light absorbed would be a
weighted average over all wavelengths. In Eqs. (12) and (13), eA
and eB are the extinction coefficients at the hypothetical single
wavelength. Given this fairly drastic simplification, the rate equa-
tions can then be written as follows:
No photodecomposition was observed in stabilized chloroform
(~0.75% EtOH) in the presence of RuCl62ꢀ. Likewise no decom-
position took place when 10 lL of cyclohexane was added to
2 mL of chloroform, nor when 0.5 lL of water was added.
Although ethanol (24) and cyclohexane (25) are frequently used
as radical scavengers and can be expected to quench the photo-
decomposition through hydrogen abstraction, water would not be
expected to react with any of the radicals in the schemes above.
It may act through ligand substitution on the ruthenium (vide
infra).
d½Bꢃ
¼ afA
ð14Þ
ð15Þ
dt
d½HClꢃ
dt
¼ b1fB

Photochemistry and Photobiology, 2013, 89 277
is a considerably stronger ligand than CHCl3 and would readily
displace chloroform from RuCl5(CHCl3)ꢀ.
Deuterated chloroform
Under otherwise identical conditions, CDCl3 decomposed less
than 5% as rapidly as CHCl3. The most likely explanation lies in
the anomalously large effect of deuteration on the C–H(D) bond
energy, which is about 25 kJ molꢀ1 greater in deuterated chloro-
form (28), with the implication that C–H bond breakage occurs
as part of the primary photochemical process. Coordination of
CHCl3 to ruthenium presents more possibilities for the C–H
bond to break, including stabilization of the hydrogen as a bound
hydride.
Effect of O2
Except at very low concentrations of O2, the yield of phosgene
was, within experimental error, independent of the percentage of
oxygen in contact with the solution, as can be seen in Fig. 4.
This argues against a photodecomposition mechanism in which a
radical is generated by the excited state ruthenium complex fol-
lowed by the chain sequence described in Eqs. (1) through (5).
This sequence, in combination with an appropriate termination
step (e.g. the formation of C2Cl6 from the encounter of two CCl3
radicals), yields a linear dependence on O2 concentration.
A product yield that approaches an asymptotic maximum
implies that an intermediate reacts with O2 to yield products in
competition with a nonproductive step, for example, deactivation
of an excited state.
Figure 3. Phosgene concentration following 20 min broadband irradia-
tion (k > 345 nm) of chloroform, shown in relation to the concentration
2ꢀ
of RuCl6
. Solid line is a numerical fit to Eqs. (12)–(16), with
eA = 20eB and b = 100a.
Effect of added chloride ion
The addition of 5 mg of Bu4NCl to 2 mL of chloroform reduced
2ꢀ
the rate of photodecomposition catalyzed by RuCl6 by approx-
imately 90%, whereas photodecomposition was unmeasurable
with 10 mg of Bu4NCl. This suggests the suppression of an
equilibrium, or pseudo-equilibrium, process, which we suggest
may involve the coordination of a molecule of chloroform, the
forward step being photochemical and the reverse step thermal.
hm
Ru
Ruꢂ
ð19Þ
ƒ!
hv
(
ꢀ
RuCl26ꢀ þ CHCl3
+ RuCl5ðCHCl3Þ þ Clꢀ
ð17Þ
Chloroform is seldom considered as a potential ligand (4), but
in fact there is NMR evidence of chloroform coordination in
some systems (26). The replacement of a ꢀ2 ion by two ꢀ1 ions
potentially adds to the driving force in a low polarity medium.
Although RuCl5(CHCl3)ꢀ may not be the photocatalytically
active species, the presence of CHCl3 in the inner sphere of the
ruthenium(IV) does present possibilities beyond those available
for outer sphere encounters.
If RuCl5(CHCl3)ꢀ is the photoactive species, the induction
period can be ascribed to the relatively slow approach to the
photostationary state presupposed by Eq. (17). Moreover, the
photostationary state can be expected to shift toward the right as
HCl is generated, due to the favorable equilꢀibrium in moderately
polar solvents for the formation of HCl2 (18,27), removing
chloride ion.
Figure 4. Phosgene concentration in 2 mL of CHCl3 with ~2 9 10ꢀ4
M
HCl þ Clꢀ ꢀ HClꢀ2
ð18Þ
2ꢀ
RuCl6 following 20 min broadband (k > 345 nm) irradiation. Gas in
contact with the solution was a mixture of Ar and air or air and O2. Solid
line is a fit of the experimental data to the expression a[O2]/(1 + b[O2]).
Each point is an average of three separate measurements.
The equilibrium in Eq. (17) also presents a ready explanation
for the quenching of the photodecomposition by water, as H2O

278 Alissa M. Chan et al.
hv
RuCl5ðCHCl3Þꢀ
RuCl Hꢀ þ CCl4
ð23Þ
ƒƒƒ!
k1
4
Ruꢂ
Ru
ð20Þ
ð21Þ
ƒ
ƒ!
RuCl4Hꢀ þ Clꢀ ꢀ RuCl5H2ꢀ
RuCl5H2ꢀ þ O2 ! RuCl5OOH2ꢀ
ð24Þ
ð25Þ
k2
Ruꢂ þ O2
Products
ƒ!
Expressing the rate of Step (19) as I0f/V, where I0 is the inci-
dent light intensity, f the fraction of light absorbed and V the
sample volume, the steady-state rate of product formation
becomes
Within this mechanism, the very slow reaction in deuterochlo-
roform is consistent with C–H bond breakage in Eq. (23), requir-
ing an additional 25 kJ molꢀ1 with CDCl3 (28), and also
consistent with the accumulation of CCl4, also by virtue of
Eq. (23). The asymptotic dependence on the oxygen concentra-
tion will arise as long as RuCl5H2ꢀ can return unproductively to
the original ruthenium complex. This is shown in Eqs. (23) and
(24) by reverse steps, but in fact the entire sequence could well
occur in a more concerted fashion.
d½Productsꢃ
dt
k2I0f ½O2ꢃ
a½O2ꢃ
¼
¼
ð22Þ
Vðk1 þ k2½O2ꢃÞ 1 þ b½O2ꢃ
This function was used to fit the data in Fig. 4.
Ruthenium hydroperoxides have been postulated for a variety
of catalytic sequences involving ruthenium complexes, including
several involving coordinated chloride ions (29–31). Isotope
labeling studies indicate that heavy metal hydroperoxides gener-
ally react by oxygen atom transfer (32), from which the follow-
ing sequence of steps can be hypothesized.
Side Products
GC-MS analysis of photolysates revealed only CCl4 and C2Cl6
as minor products, in approximately equal amounts. The failure
to find any detectable amounts of C2H2Cl4 or C2HCl5 rules out
both the photoreduction of chloroform and energy transfer to
chloroform followed by bond homolysis as primary photopro-
cesses, as both would yield CHCl2 radicals.
The detection of C2Cl6 confirms the expected role of CCl3 as
chain carrier, whereas the presence of substantial amounts of
CCl4 requires a reaction other than the termination of Cl atoms
with CCl3, which cannot be competitive with the self-termination
of the chain carrier CCl3.
RuCl5OOH2ꢀ þ CHCl3 ! RuCl5OH2ꢀ þ CCl3OH
CCl3OH ! HCl þ COCl2
ð26Þ
ð27Þ
ð28Þ
RuCl5OH2ꢀ þ HCl ! RuCl62ꢀ þ H2O
The stoichiometry of the catalyzed photodecomposition by
this sequence of steps, standing in contrast with that predicted
(and observed) for the decomposition mechanism postulated in
the Introduction, Eq. (6), is as follows:
CONCLUSION
2ꢀ
The mechanism by which RuCl6 acts to catalyze the photo-
decomposition of chloroform must conform to the following
observations:
1. The induction period before significant decomposition takes
place.
2CHCl3 þ O2 ! CCl4 þ COCl2 þ H2O
ð29Þ
2. The retardation of photodecomposition at higher concentra-
2ꢀ
Experimentally, five to ten times more COCl2 than HCl was
observed, which is more consistent with this mechanism than with
that of Eqs. (1)–(5), which predicts equimolar yields. In addition,
water was often found to form as droplets on the cuvettes follow-
ing long (>45 min) irradiation. As phosgene is slowly hydrolyzed
by water (12,33), the ruthenium hydroperoxide mechanism could
conceivably account for the HCl observed as well as COCl2. How-
ever, the presence of C2Cl6 among the side products is a clear indi-
cation that radical chemistry also takes place.
tions of RuCl6
3. The retardation of photodecomposition by added chloride ion.
4. The suppression of photodecomposition in CDCl3.
5. The formation of CCl4 as a side product in amounts approxi-
mately equivalent to those of C2Cl6.
6. The asymptotic increase in the decomposition rate with O2
concentration.
The induction period, the inverse dependence on the ruthe-
nium concentration in more concentrated solutions, and the retar-
dation by Clꢀ were proposed to result from the photochemical
formation of a CHCl3 complex together with a thermal back-
reaction as in Eq. (17). The rate of chloroform decomposition
would then increase as the concentration of RuCl5(CHCl3)ꢀ, the
photocatalytically active species, increases. The maximum con-
centration of this species, dictated by the photostationary state
from Eq. (17), is predicted to increase as HCl is generated,
removing chloride ion, whereas the maximum concentration
would be reduced, as observed, by the addition of chloride.
The remainder of the observations are consistent with a mech-
anism involving hydride formation from the excited state ruthe-
nium complex followed by the insertion of O2 to form a
ruthenium hydroperoxide.
Acknowledgement—This work was supported by the donors of the
American Chemical Society Petroleum Research Fund through grant
49334-UR3.
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