The generation and photochemistry of indenone o -oxide and fluorenone o -oxide in low temperature matrices

Ttv?dle&on Vol 41, No. 2. Pnntcd tn Great BnXain.

pp

335, to 347, t985

Re Dunkin*

Ian

of

Departmtnt

and GwdstI

A,

Bcfl

Pure and Appl ied Chemistry, University 295 Cathedral Street, Glasguw Gf 1XL.

of Strathc lydc,

Ab&ract : 2%~photufyais of diaxoindene and diazofluarene at 3% in Hz matrices containing 02 has been studied, using i.r, spect roscopp I The carbonyl oxides, indenone Q-oxide and fluorcnone poxide, were formed by the reaction of 02 with the corresponding carbenes# and under appropriate conditiona could be detected as very photolabile species, Photolysis of indenone and indcnonc Q-oxide gave isocoumarin; similar photolysis of ftuorenona $+xide gave fluarenune and dibenzopyran-S-one. Carbmyl

oxides

L and

yais,

in

ability

to

in these

species

cesses

in

axygen

detection

observation of

‘Matrix recently been

the

i.r,

idene

place, recorded,

in

by

our

aleo

the

uf the

In these i,r.

The aubsequclnt

i .r.

Cr,_e

photolpaiti of the

photollysis

to

retain

spectroscopic

between indenone carbonpl

G-oxide.9

tu

atudp further

ketone,

appears

to

or rearrange-

f&S have

of

reactions the matrix

idcnc

with

at

been

of

makixtg use

12K in I@2matrices

corresponding

and f luorenonc

t have

CO obs-

reactions

inveetigations,

has aiso

led

The photo-

ao far,

and f luorenyf

and their

arr and the oxidca

p

(2-1 and diaxafluurene

and diazofiuorcne p-oxide

indenone have

uxygeft atamas,St7*fQ

s indenytidene

spectroscopy,

studies

published both

in low-

10, Xi&dimethyt-lO_aifa-

and f luorenone

at diaxoindene

of diazaindene

of these

attributed

We now dcacribc

a reaction adducts,

photolyais

SIC-

spectra.586

@oxide,

Flash

which

interest

&oxide

absorption

the corresponding

The carbcnes

a u.v .-visible with

and i,t.

and in the cases

of moleculea

and

conditions,

spectra

Q-oxide,8

ef Etrc?r photo’fysis

reported

ions

atom to yield

laboratories.

and f luorcnyl idine

02. and

uf an oxygen

of their

and characterizatiun,

tetrachloracyclopentadienone absorpt

in ozonot-

because

of cyctopentadienone

u.v.-visible

been examined,

u.v .-visible

spectroscopy,

containing

has

studies

made

We have

ll

indenyl

isolated

inteteijtt

detection

isolation its

,7 benzophenone

oxides

isolation been

the

intcmediates

aroused

Rare recent I y ) addit ional

spectroscopic of

u.v .-visible

ejection

as reactive

and have

hari aXaa been achieved,&

one or nt~re of a variety

characterized

erved.

direct

included

matrix

one Q-oxide carbonyl

either

ment to yield

of

of

ta occur

subatrates.3*&

observation

*oxide

of transient

anthracen-9-[lOR]invclfvtl

an their the

supposed

compounda,2*3

to other

have and

r and f’luutenane

chemistry

ataas

direction

matrices

long been of diato

has ccntred

thie

U.v.-visible the

oxidation

transfer

temperature oxide

(A> have

the

carbenee

Q-oxide, examined.

have

takes been

1. R. DUNKINand G. A.

BELL

Genera 1 Procedure .- The matrix isolation technique used in this research and it8 applications to structural and mechanistic problems in organic chemistry have been reviewed elsewhere.12 The technique consists of trapping molecule8 of a guest species in a large excess of a solidified inert host-gas, such a8 Ar or N2, at very low temperatures (typically 4-20R). These Ar or N2 matrices have no host-gaa ebeorptions throughout the normal u.v.-visible (200-700 nm) or i.r. (4000-400 cm-l) regions of the spectrum, and are thus ideal for spectroscopic 6tudie8. Roreover, photolysis of matrix isolated molecules allows the observation, by ordinary sptctroscopic means, of fragment molecule8, 8uCh a8 radicals, carbenes, and nitrenea, Or highly reactive spee iee , Thermal reactions between two matrix such as cyc lobut ad iene and bentyne .I2 isolated molecules may often be induced by annealing (warming and re-cooling) the matrices at temperatures where softening occurs (typically 3b40K). A casbination of these methods has been used in this work. - The low temperature cell has been described in detail previously.13 It consisted enclosed in a glass and metal vacuum shroud and cooled by an Air Product8 Displex GSA-202 closed cycle helium refrigerator. The base temperature was 12K, and higher temperatures could be achieved by mean8 of a small resistance heater connected to an Air Products APD-B temperature controller. I.r. spectra were recorded on unmodified JASCO model IRA-2 and Perkin Elmer model 684 8pectrometer8, the latter interfaced with a Perkin Elmer model 3600 Data Station. Photolyaia was carried out with a Philips HPK 125W medium pressure Dg arc or an Oricl 200 W high pressure hg arc. In all circumstances, a water filter (13 cm pathlength) with quartz windows (A>200 nm) was used to remove i.r. radiation. Additional filtration, provided by or interference filters (X = 296 ,+ 5, 312 ,+ 5, or Pyrex (0300 nm), soda glass (A.>330 nm), 365 t 5 Ml), was used as necessary.

:P==

a CsBr window

Hateriala.Research grade N2 ({ 99.9942/j and 02 (4 99.9721) were obtained from B.O.C. Ltd,, and were used without further purification. Diatoindene (2),14 diazofluorene (2),15 indenone were all prepared by literature meth(3), 16 isocoumarin (4), 17 and dibentopyran-6-one (7)18 2s. Fluorenone (5) waz obtained as a commercial sam:le. Matrix deposition.as required and in known ratios, by Mixtures of N2 and 02 were prepared, standard manometric techniques, Because of their low volatility, all the compounds studied in this investigation were incorporated into matrices by direct sublimation on to the cold window at 20K, with simultaneous deposition of a stream of hoat-gas, controlled by a fine needlethe stream of host gas was valve. For the least volatile materials, (ft>, (51, ($1, and (11, in a aideallowed to pass directly over the crystals of gugst compound, which were contained of the cold cell. to the vacuum shroud arm attached In theee circumstances, matrix ratios (host:guest) could not be estimated. Matrices vere cooled to 12R immediately after deposition.

Scheme 1,

Two diato ysed

in

the

results

cOrnpounds, diatoindene

02-doped for

Diazoindene ulted,

and the

those

Wide-band

20 min,

ion were indenone um with

at

each compound will

(1) .-

after

2086 cm-l]

N2 matrices

in

(2)

12R.

irradiation

of

a complex (51,

(3-1 and (5)

(5_>, have

were monitored

been

isolated

by i.r.

and photol-

spectroscopy,

and

separately.

(0330

complete

and isoeoumarin

of authentic

and diazofluorene T’he reactions

be described

almost

appearance

(2)

nm) of (2)

disappearance

at

new i .r . spectrum. identified

isolated

in

12K in N2 containing

of the

bands

lot

of (21

The main products

by comparison N2 matrices.

i.r.

of this

of the product Table

1 comprises

i.r.

02 reb[Y(CNN) reactspectr-

a detailed

Generation and photochemistry of indenone O-oxide and fkorenone O-oxide

comparison pure

of

lintits

were

(Z?. cm-l), presence bands

but

and &)

and

indenylidene (see

a product

photoiysis

whose

(&)

gave

all

in

%-doped

photolysis

was slow

but

reaction

.

was responsible

decomposition

did

1t apptared ,

the observed

bands

(cm-l),

to

that

CO2 in the

some kind photolysis

carbonyl observed

indenone

(2)

neither that

irradiatthe

rather

the

rate

than

of (5).

(3)

(4)

1,

1779 1759s 1746s

1760st 1749s 1724s

1729s

1717s

Photoproduc te fraP (2)

1151 1140

1712 164 lm

1118 1106

1605

10% 1047 1040

1600 1549 1490x3 1479 1467

1457

1014 1003 145s

1447 1415 1387 1370 1352 1333

1371

795 781 77ckn 758111

1328~~ 1322 1315m

131s 1311 1285111 12771~

1288 1280 1254m 1242 1231 1208

1246

1183 1177

1160 1736

161%

1547 1491

(5)

1193 1184

1722s

1642 1612m

(2)

1117 110s 1080 lOSSa 1047m 1039 1033 101s 1005 983 974 891 827

1014 1OOlUl

7949 780 77&l 76 lr 750 719

714 692

1279m 1253s

?14 462

1231 1207

692m 495

. band

intensities:

bands

were weak unless

denoted

s (strong)

of

photo-

in the region 2000-400 CIP-~, of the photoproducts from (Z_) in 02-doped and of authentic (2) and (5) in N2 matrices. N2 matrices.,

Photoproducts frog (2)

t Qualitative

and

comp-

of 11,

of secondary of (z),

on

a secondary

but

of 02 increased

to

increase

therefore,

however,

and

not belong

With 02 levels

concentrations

product

1352,

was aleo

of the CO2, both

It was found,

therefore,

1387,

11 or to the

in pure N2 matrices,

in CO2 formation. higher

at

continued

CO2 was,

the origin

in the

They did

observed,

by the

of the weak few overlaps,

weak bands

and 661 cm-l)

however,

to photolyse. result

while

for

been

CO2 (2347

mm) separately

TABLE

1.r.

recently

induced

a third

occurred

and these

reproducibility

surprisingly

product.

had disappeared.

to ascertain

discernible,

significantly

third

concentration,

CO2 nor appeared

with

These

02-doped within

shifts

and over

Only three

or (4_).

to (3_) and (k),

(X,330

matrix

bands

spectrum,

between

differences

experimental

small

also.

apec trum has Its

N2 matrices

product

(2)

the diazoindene

irradiated

any detectable

unimolecular

i.r.

In an effort were

of the

to any obvious

photolysis,

after

ion of (4)

formation

to either

of

intensity

intensities

assigned

matrix

(up to 25 cla’l)

Tht larger

variations

medium

in the

Ln addition

product.

isocoumarin

CO2 oxidation

to beAong

below). even

and

of relative

not be

in this

irradiation,

ound

not

(a),

(2)

strong

identifiable

match

could

estimated

in our experience,

of the

were

differences

some of the bands.

than

typical,

All

appeared

cm-f,

oxide

were

frequency

for

greater

a reasonable

spectrum

Small

apparent

certainly

of (2)

1160

spectra. were

of 02,

and with

as

the

N2 matrices

or m (medium).

a

1. R. E)UNICIN and G. A.

342 The

photolysis

concentration a8 (2)

and

resulted, in the

could

of

but

most i.r.

had

noted),

and was probably

306,

and

with

312 nm light,

(z).-

diazoindene.

in

All

portion

the

weaker

of

occurred.

Small

at

belong the

1219,

oxide

i.r. Other,

13’ 02,

no inden-

with

312 nm I ight

(105 min)

(2,

and (kft,.

This

new

(weak

except

as

and 488 cm-l

during

Of (2)

the

and (5)

precursor

annealing

experiment

the new species

was noted.

within

Irradiation

of (3-1 and (5).

of

(2)

concentration other

of (1) (A>330

8nne8led,

in

the

growth

spectrum,

could

spectrum

in N2 matrices (E)

spectrum of 8n i .r.

containing

(strongest

mede this

is

only

bands

above). recently

at

These

not

weak bands

observed,11

produced

in this

result

in the

clear.

O.lt

02 probably

produced

1035 and 755 cm-i),1l

was barely

apparent

Only three been

did

yet

to decide

difficult

band at 898 cm-l

not

at

overlhpping were

to (51 or (2).

N2 matrices

of (1)

8-e

spectrum

amount of CO2 was also

in the photo-oxidation nm)

although

has

of

of the

in pure N2 matrices

by 02 (see

i.r.

A small

fonncttion

and (7-1 and 8 goo%i pro-

matrix

not be assigned

(A>330 nm) in N2 or 02-doped

of fluorcnylidenc

bands

product

with

101 02 resulted,

by cmparison

of (5)

in the 02-doped

we obtained

and the

isoleted

bands

to perturbation8

below).

2070 cm-l]

were identified

i.r.

in the

to those

12K in N2 containing

(k> and (1)

whose matrix

(see

similar

[Y(CNN)

The products

of authentic

(161,

origin

were very

of (2)

and 814 cm”,

(17)

irradiation

Photolysis

was

8nd

to h8Ve arisen.

(A>330 nm) removed

(up to 26 cm-1)

to fluorenylidene

carbonyl

formation

matrix

634,

mu) of (5-1 at

(1).

and were attributed

of CO2, so its

with

ae well

quality

containing

along

~88 formed

and medium intensity

shifts

1370,

but

lap

(0330 photolysis

one8 were recognized

reaction,

small

that irradiation

diazofluorene

those

strong

frequency

bands,

not

912 m, 852,

a photol8bilc

with

with

the

some of the bands,

to

optic81

narrow-band

a new product

in the 8b8OrptiOn8

complete

8b8OrptiOnS

i+r, 21.

did

species

with

101 9)

938,

wide--band

irradiation

almost

12R [Table

or

same

(k!, and dibenzopyran-&-one

product

for

the

Our results

Wide-band

10 ain,

product

1076,

produced

a 8m8ll

2.

Diazofiuorene

f luorenone

was seen

02 produced

and 741 cm’*‘)11

of (21.

1465,

therefore,

0.11

751,

NZ matrices

With

containing

increase

oniy

1302,

at 912 cm-1

compound and gave

Subsequent

1305,

in it8

band

photolysis

containing

at

8 deterioration

definite.

at

an accompanying

Scheme

after

bands

above.

i.r. less

(N2 matrix

species

described

8 new were

of the diazo

bands

was annesled,

after

(2)

nm> in N2 matricee

(p> (strongest

spectrum

be detected

Irradiation photolyaed

(A>330

When the matrix

changes

ylidene

(2)

indeaylidene

(g).

band-broadening minor

of

of

BELL

with

but

certainty,.

perceptible

a

over-

When the

amongst

general

band-broadening. Irradiation resulted

(2), 770,

in

of 8lmObt

(1)

dibenzopyran-6-one and

probably removed Irradiation

732

cm-l.

belonged

(21, to the

containing

photolyeis and a third

The 898

the new species with

(N2 matrix

complete

cm -1 band,

species seen

312 nm light,

therefore,

02)

the

with

Three with

i-r.

intensity

p rodueed

narrow-band

photoproduc

ts

absorption8

to grow in the

Subsequent

s8me species. and increased

lot

of (5-l.

of the

on photolabile

band8 precursor

(29 min) fluorenone

:

898 m, 881,

experiment

irradiation i.r.

formed

at 975,

annealing

wide-band

312 n.m light

were

(see

(A>200 nn) due to

(&>

783,

above), for

and

of (g> and (7-j.

15s (2).

Photoproduct* from Q>

Photoproducta EfcMaQ,

17301EI 1703 IfilSa 1505m

1491 IQ&m 1437 IJPCI

1303#

tfE‘t9 Et2 band

intensities:

Phato-oxidat ion af diatoindcna b3_) and isocsuaaript

photoiyais of

(2)

adduct

indenyridene


its

Secondly, containing

subsequent

reported

in

idtntified

8s

The

this

the

photoipai@ matrices; (2,

sf

C@xidc,

Scheme 3.

One of the abaexved (9-1

in the

un wideband

8 highly

ie absence

containing

photofyais

yields

?&sre discrim-

photolabile

as indanone &oxide

intermediate

of (2,

matrices

l]*

of a highly

spec5es the

phatsfysia

Pn 02”doped

products+ [Scheme

the detection

Piratlyr

pre-

{9_)&

aimileir

of 02 is both

photolabiia

have

farvours

species

of cyclopentadienone

already with

demonstrated

SLR

known ta

(g-1 and C&Jore

of tbt intermediate

ta the chemirtry studier

The

afmaet certainty

the laude of formatian af the intermediitte

U.P .-visible

carbonyl

rrimpfified

from

allows

Thirdly,

[path

oxides

and rreveraf

A atightly ato*

of (2)

of &her

intermediate

Matrix

cioaely

or m (medium?.

st rend

e-oxide

thst (31 and

Amax = 44§ x11*$ which

ia

erlacr

-4

photochemistry

ryc~ep~ntadienane

phbtoiyeis

traces

this

of (5)

are gioe

672 651

wtzre weak uniess deno&ed s (s!xang)

onfy

atoms,

Feurrhly, to

t55m 742s

eeems ZQ arise whr?nmatrices

femation

two oxygen

898

672 652 626

xtaaignment v

intermediate

9193

725 685

Wide-b*&

with

t-8, rrfid U2*

previoualy.5~10

02 react

(2, .-

f&j,

supports

11 and the

annea led. structure

1078 LU39m 9l8m 89s 814 761m 755 ) 742m

<% = 312 $ 5nrrr), however,

evidence

of

bands

and (4;>, and we identify

fot lowing give

fu94m lo92

12 ilrm

tQualitatiu6

inrting

1130 1107

1323 1307m 1297 1285 f26Ta 1242m 1227

12% X265 1242

cursor

I154

1533m 1599m 1509 1;49un 146im t43gm

145Sim

i306m

indenme

1195

1782 t765s 1756s 8734

1764sI l?Z3ii 1738 1729a f7QO 16 Sdm 15998

adaptation ]*

of this

plauaibfe

of the various products,

although

‘indenone so far

type

haa been discussed

reactian proposals

p8thW8ys

have

to indenone

(3-1, arisca;by sirplo

we have

been unable

in cennectien been poxide ejection

to determine

proposed

with

+10, kg

ia given

in

of an oxygen the

Eata sf

I. R. DUNKIN and G. A. BELL

Generation and photochemistry of indcnone O-oxide and fluorenone O-oxide ejected

the

atom.

arrangement verified.

(110) [path

the

product

(&I.

arguments

route

(9-1 via

photodecomposition

and this

has been

taken

to favour

path

pathway

[path

it

would The

reaction. case,

seem

fluorene

& of

unlikely

G-oxide

O-eta

(3) the

(see

it

route

between

(2)

2130 cm-l] g-oxide

detect

in

applies,

the

oxide

spectroscopy,

460

nm),6

it8

i.r.

the

photolyeis

(51,

while

atams, asbume

as

a transient

spectrum

has

of

does

and bonding

shown thus that

that

the

in carbonyl adduct

excluding the

out

oxygen

of

in the

occurs

quite

to have

path

(b)

oxide

(2)

with of the

its

path lie

(&I

[Y(CCO)

Failure

intermediacy.

driving

(d).

on the

of cyclopentadien-

rr-pyrone.lOllgt21

against

in

terminal

been directly

ketene-aldehyde reaction

the

of

readily

that have

(z),

in any

the

over

intermediates

in the

of

as a product

of (2)

force,

to

With re-

ring-closure

Narrow-band photolabile Foxide

of

to that

X.r.

atom

no ketene of

studies

such

for

this

we assign

before

no previous

from (17) or

by u.v .-

intermediate

leads

(&6ax= report

of

be drawn

for

to fluorenone

dioxirane,

a

t

the

in the

with

photolysis

the of

a species.

exploiting

isotopically has

molecule

of (S_, and (16)

fluorenone

312 ? 5 nm)

(2) mey also

a dioxetane

prosection

in N2 matrices

but

shown for

an oxygen

gave

to which

(16)

studies,g

matrices previous

(A=

has been detected

cyclopentaditnylidene

structure adducts

Clf 1

be derived

we observed

matrice

intermediate,

photolysis of

in the

irradiation

of 02 and ffuorenylidene

intervention

with

of (5-1 in 02-doped

of (5-1 in 02-doped

23.

could

oxides.02

analogue

irradiation

(21, the

a dioxirane atoms

the

in flash

(7)

rule

The state,

in (fl) might,

to favour

not detected

A Scheme similar

As with

not

forward.20

photo-oxidation

t and much of the discussion

Photo-ejection

probable.

this

possible. especially

transition

position

possible

The photo-oxidation

of (z)

species

(17).

the

part

of a very

been mdde.

also

to

observed

efficient.

an adduct

dibenzopyran-6-one

more but

Structure have

and

required

as an important

Fluorenonc

as

the


though

[Scheme

(lJ>.

for

apparently

evidence

Wide-band

both

put

delocalised

preference

in photo-equilibrium

observation

structure

attack

is

we have

(5_>.-

(2)

has been

the bridgehead

such

is

be considered,

was not detected

which

at

as reliable

to that

mutandis.

earbonyl

former

ring

dibentopyran-6-one

visible

even

luorene

manner

permitted

that

to be very

of diasof

mutatis

however,

is

be taken

benzene

z-oxide

(ii)]

(i)],

in the

fc) .l”

of all

the earbene

and exists

likely

also

(151,

that

that

known,

a similar

and

only

[path

should

out

but

may be all

however, the

(k> is

Photo-oxidation ceeded

(g),

(2).

to (4)

A conformational

emphasizing

noteworthy

well of

to give

(5)

and

cannot,

aromatization (fi)

ring

(2)

to be

of a di-

[path

result

can be ruled

oxygen

grounds,

in our experiments,

is

(14)

to coumarin

would

remains

formation

and ring-opening

the more highly

path

A number of re-

followed

initial

(cl]

a thione

over

(d)]

below).

worth

Specially

detected. ca.

is

for

(b)

terminal

on steric

(11)

away from the benzene

Finally,

one

lead at tack

however,

route

ring-closure

would have

(b)],

of (2).

ismer

favour

bond-cleavage

(Ii_) [path

route

[path

because

0-O

an

the exact which

from the diradical

route

dioxetane

but

electracyclic

dioxirane

dioxetane A second

r&t,, is

(21,

can be advancedlo Final

An alternative

an analogous

for

fol lowed by

(b)],

of

isocoumarin

written

ketene-aldehyde(&).

Rearrangement since

product,

may be

Nevertht~ess,

oxetane give

The other

pathways

with

Labelled

two non-equivalent

.5 02 will

oxygen oxygen

St is reasonably

safe

be similarly

di .sposad.

to

I. R. DUNKIN and G. A. BELL. The

rather

with

emall

%lmx = 460

nm)$

(E)]

than

strong

of

bonding

the

ab

[cf.

(2)

is

provide

between

(k)]

of

have

sought

structure

to deduce is

provide

On the

ground the

are

was be

generated

or less

more

factor of

the necessary

very

difficult

to

even

as

little

a6 O.lf

(I?)

in

annealing

of

in

give

a triplet

the

formation

well

with

that

the

This

investigation

in low-temperature

idene


and (g),

(16)

oxide

would

CO is

of

between of

i.r.

a triplet

these

(la)

to exist

unlikely

to

of

3OK

Both carbenes

does

condition8 the thermal

suggested

that

now tieems much It

has proved

in matrices

there fore,

a great

containing of

(9_) and

difference Such a

snd 02 on the other. based

electronic The high

on steric

taking

effecta,

the simplest ground

reactivity

of

ground

view,

state

spin-inversion,

singlet

the

or may be

in origin

and triplet

of

to give

CO and the

in these

formation

arguments

in favour

triplet

on the pathway.

the

Thus,

a rate-limiting

both

and oz.

carbenes

is,

of

not.

It ia

have

matrices

possibilities

observation

carbene

would

[cf.

the biradical

sre

some point

or (16)

There

a8 evidence

in

Some author6

that

because

to about

CO, on the one hand,

oxide

oxide

at

these

(a)

due to spin-inversion.

carbonyl

from

twitterionic

opt ion8.

CO may be steric

with

8enne in the context

be interpreted

do not

to the bonding

We have previously

rate.

The first

involve

bond

inference

eomewhat limited.

the matrices

marginal.

between

(fb)

since

must occur

or (16)

toward6

the

CO in low-temperature

towards

which made the

180,

double

we can now be more definite.

reaction,

concentration8

rather

reaction

02 to whereas

(g)

state8

and (16) for

(9_)

by theory.3e*22*23

wab an i.r. matrices

and fluorenylidene respectively,

(6)

nature

and its

(9_) and (17)

absorpt ions

and seem to be able

reaction

facile

a fact

a singlet

a8 predicted

1X,

of

rate-limitation

02 may therefore

and (u),

at

of

and fluorenylidene

with

upon warning

make8 little

carbonyl of

($_I and (16)

detectable

(&_) and

difference

fits

towards

02,

react

at a reasonable

experiments

reactivity

we propose

(2)

generate

(g)

an interesting

spin-inver8ion.11

owing to the very

reactivity but

place

oxide6

spin-inversion

of

in the reaction

likely,

the

ie

Only

take

carbonyl

carbenes

This

evidence

issue.6

indenylidene

pure CO matrices

leas

in

these

of

Experimental

and ylide-type

a carbonyl

the ground

however,

Thus,

plausible

the electronic

this

to

R=R)],

substantial

structure

(la)]

of

and

description

&oxide

spectra

i.r.

frar

spectrum

(2)

or twitterionic

having

two, aa

the

that

(g>3.

conclusion.

[cf.

of

is

of

both

an elec tronie

in

The

biradical

deciding

states

the reactivity

addition

rate-limiting result

of

indefinitely.

ketene-forming

the

mean8 of

that

Both

a structure

that

(1,

cyclopeatadienone

contribution

hybrid

our view

ketene6,ll

that

leaves

agree

[e.g.

and the biradical

new to this

u.v-visible

the spin

singlets,

found

but

but

studies

8tate6.25

add little

oxides

[cf.

with

[e.g.

would be expected

a zwitttrionic

description

and oxy&en.5**4

froau the

of

e.s.r.

corresponding

ketenes

type,

carbonyf fuvour

of

02

skeleton.

examples

states

of

fluoreaylidene

structures

latter

substituted

spectra

a substantial

and reliable

question

from

the ground

or a resonance

preferable,7

a simple

known

this

schemes,

least

compatible

but

against

on simple

The i,r.

seem

the

on the carbocyclic

a biradical

of

rpatse.

evidence, is

oxide6

bonding

prefer

character

the ring-carbon

any contrary

carbonyl

For the

oxide

since

and generally

the adducts

10,10-dimethyl-lO-sila-anthracea-

carbonpl.

(lo)),

of

(Amax x 445 ran),’

and

to fsvour

dependent

absorption8

indenylidene

[e.g.

and (&)I.

do not

spectroscopy

i.r.

tends

be singlets,

rather

analagues

character

also

8tructures

should

singlet

bonding

labeiled

na)7

calculations

to the

the

the electronic

(Amax = 410 ~4,~

absorption6

species

initio

relating

of

maI,6

and HINDU/3 calculation83et*3

these

the

= 425

dioretane

poiyene

io**

Ab init states

can

(Amax = 410

($,,ax

rather

exhibit

It

in the positions

diphenylcarbene

9[LOH]-ylideae

of

variation

cpclopentaditnylidene

(l6), Matrix

study

containing react

of

the photolysis Under

02. with

i .r . spectra

02 to give for

these

of

these

diatoindene eondition8,

the corresponding species

are

(2)

and diaxofluorene

the carbene8, carbonyl

reported.

indenyl-

oxides,

Sub sequent

(2) phot-

347

Generation and photochemistry of indtnone O-oxide and fluorenont @oxide olysis

of the

ketone6 the

(1)

carbonyl or

(51,

oxides and

photo-isaneritation

pentadienonc possible based states

routes. for

the

oxides

S.E.R.C.

oxides and

discussed,

The nature

reactivity

carbonyl

We thank

are

of the bonding

of

(i)

two routes:

an isameritation,

of carbonyl

g-oxide,

on the

follows

(ii)

(8)

(0)

for

and

(t6)

and (g),

supporting

the

yielding

(2)

and (g),

in carbonyl

as predicted

this

of an oxygen

atom,

lactones

(&I or (1).

Mechanisms

baaed

some attempt towards

ejection

on earlier

proposals

is Made to decide oxides

02 and CO is by published

work with

is

also

taken

discussed,

for

for

cyclo-

the various and evidence

to fsvour

theoretical

a studentship

between

yielding

singlet

ground

studies.

(G.A.E.)

and equipment

(I.R.D.).

1. (a) R. Criegee and G. Wenner, Juotus Liebi s Ann.Chem., 564, 9 (1949). y;.Qlstll:PrO&*, l8* 111 (1957); An*eW.Che:Iat.gd.gn*l.* 14, 745 (1975). (b) R* Criegee’ 2. a W. Kirmse, L. Homer and H. Hoffmana, Justu8 Liebigs Ana.Cbm.,614, 19 (1958). (b) P.D. Bartlett and T. G. Traylor, J.Am.Chem.Soc., 84, 3408 (1962). cc) 8. W, Murray and A. Sutui, ibid., 93, 4963 (1971); ibid., B, 3343 (1973). cd) D. P. Higley and R. W. Murray, ibid. , 96,333o (19741. (e) T. A. Hinrichs, W. Ramachandran and R. W. Murray, ibid., 1282 (1979)‘ J.Am.Chem.Soc., 88, 1584 (1966). (b) S. K. Chaudhary, 3. (a) G. A. Hamilton and 3. R. G&in, R. A. Hoyt and R. W. Murray, Tetrahedron Lett., 4235 (1976). (c) W. Ando, Y. Kabe and B, Hiyataki, Photochem. Photobiof., 3i, 191 (1980). (d) S. Kumar and R. W. Murray, Tetrahedron Lett., 4781 (1980); J.Am.Cherr.Soc., 106, 1040 (1984). (e) Y. Sawaki, R. Kato and P. Ogata, ibid., 103, 3832 (19811. (f) A. Sekiguchi, Y. Kabe and W. Ando, J. Org. Chem., 47_, 2900 (1982). 35, 31 (1982). (b) II. Kwart and 4. (8) S. K. Agarwal and R, W. Murray, Photochem.Photobiol., D. l4. Hoffman, J.Org.Chem., 3l, 419 (1966). (c) W. A. Pryor and C. K. Govindan, J.Am.Chem. Aromatic Hydrocarbons: &&,u, 7681 11981). (d) R. W. Murray and S. Kumar in “Polynuclear Physical and Biological Chemistry,” ed. M. Cook, A. J. Dennis and G. L. Fisher, Battelle Press, Columbus (1982) p.575. 1213 (1983). 5. G. A. Bell md I, R. Duakin, J,Chea,Soc.,Chem.Co~~., I. R. Dunkin and C. J. Shields, to be published. 6. G. A. Bell, R. Hayashi, A. Sekiguchi, W. Ando and W. T. Liu, Chem. Lett, 7. T. Sugawara, H. Iwamura, 1261 (1983). 8. (a) N. Ii. Werstiuk, Ii. L. Casal and J. C, Seaiano, Can,J.Cher., in press. (b) 8. L. Casal, S. E. Sugamori and 3. C. Scaiano, to be published. We thank these authors for preprints. 8. L. Casal and J. C. Scaiano, to be published. 9. A. H. Werstiuk, We thank Dr. Scaiano for advance disclosure of this result. 10. 0. L. Chapman and T. C. Hess, J.Am.Chem.Soc., 106, 1842 (1984). in press. 11. G. A. Bell and I. R. Dunkia, .Y.Chem.Soc.,Faraday Trans.2, 12. I. R. Dunkin, Chem,Soc,Rev., 2, 1 (1980). J.Chcm.Soc., Perkin Trans. 2, in press. 13. (a) I. R. Dunkin and J, G. HacDonald, (b) J. G. MacDonald, Ph.D. Thesis, University of Strathclyde, Glasgow., (1980). Angew.Chem.Xnt.lM.Rn~., ll, 44 (1972). 14. D. Rewicki and C. Tuchecherer, 100, 4475 (1978). 15. R. A. Moss and M, A. Joyce, J.Am.Chem.Soc., J. Org. Chemr43, 1835 (1978). 16. B. H. Szmant and R. Nanjundiah, L. E. Kaslow, A. Langsjoen and R. L. Shriner, J.Org.Chcm., 13, 477 (1948). 17. H. W. Jonston, J.Am.Cher.Soc., 77, 2287 (195s). 18. W. D. Emons and G. 8. Lucas, 51, 331 (1979). 19. 0. L. Chapman, Pure Appl.Chem., N. Harrit and A. Rolm, J.Chem.Soc., Perkiai Trans.1, 1404 (1976). 20. L. Carlren, 21. (a) 0. L. Chapman, C. L. McIntosh and 3. Pacansky, J. Am. Chea. Sm., 95, 244 (1973). (b) R. G. S. Pang and J. S. Shirk, ibid., 9S, 248 (1973). J.An.Cher.Soc., 97, 3064 (1975). (b) L. S.Harding 22. (a) W. R. Wadt and W. A. Goddard, III, and W. A. Goddard, IIK, ibid., lo0, 7180 (1978). 2t80 (1978). 23. L. A. Hull, J. Org. Ch”Ts, has been argued (Ref. 10). but on the basis of the i.r. spectrum of ubat 24. The opposite is apparently a different &ecies (Ref. 6). __ L. Barash, A. El. Trotzolo, R. W. Murray and W. A. Yager, J.Am.Cheu.Soc., 25. fa) E. Wasrcraan, (b) E. Waseeman, A. Il. Trottolo, W. A. Pager and 8. W. Murray, J.Chem. &, 2304 (1964). Phys. ,40,2408 (1964). (c) R. W. Brandon, G. L, Gloss, C. 15. Davoust, C. A. Rutchison, Jr., B. E. Kohler dnd R. Silbey, ibid., 43, 2006 (1965).