Po/yhedron Vol. 2, No. 9, pp. 907-916, 1983 Printed in Great Britain.

0277-5387/83 53.00 + .OO Ftrgamon hsa Ltd.

SOME NOVEL TRIORGANOTIN(IV) DERIVATIVES OF fi, 6 -TRIKETONES

ANIL KUMAR and B. P. BACHLAS* Department of Chemistry, University of Rajasthan, Jaipur 302004, India

and

JEAN-CLAUDE MAIRE Universite de Droit, D’Fconomie et de Sciences D’Aix-Marseille, Facult’e des Sciences et Techniques de Saint-Jerome Laboratoire des Organometallique, 13397 Marseille Cedex 4,

France

(Received 7 December 1982; accepted 11 February 1983)

Abstract-Thirty triorganotin(IV) derivatives of the type R,Sn(R’COCHCOCH,COR”) and [R,Sn], (R’COCHCOCHCOR”) (where R = CH,, C2H5, n-C3H7, n-C,H, and C,H, and R’ = R” = CH3, C6H5 or R’ = C6HS, R” = CH3) have been synthesised by the interaction of R,SnCl with mono- or disodium salt of 2, 4, 6-heptanetrione, 1-phenyl-1, 3, 5hexanetrione and 1, 5-diphenyl-1, 3, 5pentanetrione in 1: 1 and 2: 1 molar ratios, respectively. The complexes have been examined by their molecular weight, IR, PMR and elemental analyses and their tentative structures assigned. Both “Z” and “E” forms have been identified in the 1: 1 complexes in equilibrium with the enol form containing five coordinate tin. The 2: 1 derivatives contain one five- and other four coordinated tin(IV) except the phenyl analogue where both the tins are five coordinated.

There has been an upsurge of interest in the development of the chemistry of /I, 6-triketones,1-‘5 their Schiff s bases9*16 and compartmental ligands.“19 These ligands readily form homo- as well as hetero-bimetallic complexes. However, no work appears to have been done on the triorganotin(IV) derivatives of 8, b-triketones. The work on diorganotin(IV) has been recently completed in our laboratories.m In the present communication we report the syntheses and characterisation of thirty new derivatives of /?, &triketones.

EXPERIMENTAL

The syntheses of the ligands and their character- isation are reported earlier.2’22 All the reac- tions were carried out under anhydrous conditions.

Carbon and hydrogen were analysed on a Col-

*Author to whom correspondence should be ad- dressed.

man Carbon-Hydrogen Analyser. IR spectra were measured in Nujol mulls or neat between the range of 4ooo-2oocm-’ using CsI optics on Perkin-Elmer Model 577 spectrophotometer. The PMR spectra were recorded on a Perkin-Elmer R12B Spectrometer (60 MHz) in CDCl, or Ccl, solutions using TMS as a reference.

Synthesis of trimethyltin -mono(2, 4, 6-hepta- netrionate)

A benzene solution of trimethyltin chloride (0.01 mole) was added to the mono sodium salt of 2, 4, 6-heptanetrione (0.01 mole), prepared by the direct interaction of the latter with sodium isopropoxide (0.01 mole) in benzene. The mixture was refluxed for 2 hr. The sodium chloride so formed was filtered out and the solvent stripped off under vacuum.

The complex is red viscous liquid which solidifies on keeping. It is soluble in chloroform and other polar and non-polar solvents. The compound de- composes above 150°C. Found: Mol. Wt., 284; C,

907

Tab

le

1. P

repa

rati

on a

nd p

rope

rtie

s of

tri

orga

noti

n(IV

)-m

ono@

, St

rike

tona

tes)

Wt.

of R3SnCl*

Wt. of ligand*

Colour and

Yield

M.P.

X of C

x of Ii

x of sn

Mo1.wt.

(g)

state

(9)

(9)

Oc

czz)

~~]

FCUnd

in freez-

UklC.)

ing

benzene

FoUnd

(Calc

(i)

‘a-l3

),S

n K

x3c~

cccH

2coc

H*

1

2.98

2.13

(ii)

(CzH5)3sn(~3C~coc~H3)

1.20

0.71

(iii) (~-C3~)3Sn(CH3COMc~*c~3)

1.41

0.71

(id)

(~-C4Hg)3Sn(CH3C~C~2COCH3~

1.62

0.71

(VI

(C6H5)3Sn(CH3CCCHCOCH2COCH3)

1.92

0.71

(vi)

a3

)~S~(C~H~CCXXCOQ~~CIYZH~)

1.99

2.04

(vii) K2H5)3Sn(C6H5COCHCOCH2COCH3)

1.20

1.02

~biii~~~-C3~~3Sn~C6H5CocHCocH2CocH3~

1.41

1.02

Red solid

Red viscous

liquid

Light red

viscous

liquid

Yellow brown

viscous

liquid

Light brown

solid

Brown solid

tight red crysta-

lline solid

3.31 Decom-

pose

150

1.34

1.44

1.99

2.13

3.22

1.92

2.14

90

130

100

39.0

2 5.

69

38.38

284

(39.

39)

(5.9

4)

(38.92)

(304)

60.82

4.63

23.92

465

(61.13)

(4.92)

(24.16)

(491)

48.7

9 5.21

32.18

349

(49.09)

(5.49)

(32.34)

(367)

55.61

6.96

26.27

430

(55.90)

(7.14)

(26.32)

(451)

34.03

320

(34.20)

(347)

30.11

366

(30.34)

(391)

27.25

408

(27.52)

(431)

28.72

382

(29.01)

(409)

(ix)

(~C~H~)~S~(C~H~CCCH~~CH~COCH~)

1.62

1.02

(XI

(C6H5)3Sn(C6H5COCHCcCH2cOCH3)

1.92

1.02

(xi)

(CH3)3Sn(C6H5COCHcOcH2COC6H5)

0.99

1.33

&.I)

(C2H5)3Sn(C6H5COCNCOUi2COC6H5)

1.20

1.33

(xiii)

. (pC3H7,),Sn(C6H5cOCHcOcH2COC6H5)

1.41

1.33

(xiv)

(~-C4H9)3Sn(C6H5cWXCOCH2CCC6H5~

1.62

1.33

bzv)

(C6H5)3Sn(C6H5CCICHCOCH2COC6H5)

Bro

wn

visc

ous

liC&Iid

Dirty yellow

solid

Yellow cryst-

alline solid

Brown solid

Yellow crysta-

lline solid

Brown visam*

liquid

Creamish solid

2.25

-

2.51 >3OOd

1.92

95

2.07

128

2.26

102

2.12

-

2.52 did not

melt up

to 360

64.85

4.58

(65.13)

(4.73)

55.53

5.28

(55.98)

(5.16)

58.35

5.72

(58.63)

(5.98)

60.29

8.52

(60.84)

(6.67)

68.12

6.02

(68.32)

(6.22)

24.28

(24.06)

21.90

(21.45)

28.02

(27.65)

25.39

(25.18)

22.95

(23.12)

21.49

(21.37)

19.46

(19.28)

468

(493)

526

(553)

402

(429)

491

(513)

424

(555)

587

(615)

l

Both the reactants were taken in lrl molar ratio and refluxed for two hours.

Tab

le

2. P

repa

ratio

n an

d pr

oper

ties

of b

is[t

rior

gano

tin(I

V)]

-mon

o@

6-tr

iket

onat

es)

Wt.

of R3SnCl*

Wt. of ligand*

Colour and

Yield

M.P.

% of C

%

of

H

% of srl Mo1.wt.

state

(9)

(9)

(g)

Oc

Found

Found

Found

in fraez-

(Ca1c.j

(CalC.1

(Calc.)

ing

benzene

FoUlId

(Ca

l-z.)

(i)

(ii)

(iii

1

(iv)

(VI

(vi

)

(vii

1

~~3)3Sn]2"313COCHCOCHCOCH3)

1.99

0.71

I_(C~H~)~S~]~EH~COCHC~~~~CH~)

2.41

0.71

~pC3H7)3saJ2mi3coCH~MH3)

2.83

0.71

~'L‘C,H~)~S~]~(CH~~~~C~~)

3.25

0.71

c (C6H5)3Sn~2(~3coQ1cocHCocH3)

2.71

0.50

~Q13)3Sn~2(C6H5COCHCOCHCOCH3)

1.99

1.02

2.41

1.02

(Viii

) ~"-C3R7)3Si~2(C6H5COUiCCQiC~3)

2.83

1.02

Red viscous

liquid

Red viscous

liquid

Red viscous

liquid

Red viscous

liquid

Yellow solid

Yellow crysta-

lline solid

Light red cryst-

alline solid

Orange solid

1.52

-

2.35

-

2.62

-

3.12

-

2.63 936Od

2.08

132

2.65

94

3.22

54

33.12

5.46

50.30

449**

(33.38)

(5.60)

(50.74)

(467)

42.82

528**

(43.01) (551)

37.13

-

(37.31)

32.71

689

(32.95) (720)

61.12

4.33

28.05

-

(61.47)

(4.55)

(28.25)

40.54

5.24

44.61

499

(40.80)

(5.32)

(44.80)(529)

46.58

6.18

38.19

586

(46.95)

(6.56)

(38.66)(613)

34.12

673

(34.00)(698)

(ix)

ix)

(xi)

(xii)

3.25

1.02

3.85

1.02

I (~3)3Sn)2(c6H5cOCH~~~6~5)

1.99

1.33

c (C2H

5)3S

~]2(

C6H

$CC

HC

OC

HC

OC

6H5)

1.20

0.

66

(xiii

) ~~-c3H,'3Sn]2'C6H5CCCHCOcHCcc6H5)

Orange solid

(xiv

)

(xv)

2.83

1.33

1 (pc4Hg)3~~~2(c6H5c0c~c~~c~6H5)

3.25

1.33

c (c6H5)3sn~~2(c6~5coc~~coc6~5)

3.85

1.33

Red viacoua

liquid

Brown solid

Creamiah solid

Light red cryst-

alline solid

Red viscous

liquid

Yellow srrlid

3.70

-

4.15 >36Od

2.56

127

1.51

99

3.53

105

3.95

-

4.19 )36Od

63.61

4.58

(63.90)

(4.46)

46.13

4.92

(46.67)

(5.10)

51.15

5.98

34.89

650

(51.52)

(6.26)

(35.11)

(676)

67.91

4.08

(68.50)

(4.39)

30.56

749

(30.34)

(782)

26.21

854

(26.30)

(902)

40.14

563

(40.10)

(591)

31.24

-

(31.22)

28.43

805

(28.11)

(844)

24.57

-

(24.61)

* Both the reactants were taken

in 2x1

mo

lar

rati

os

and reflwed

for four hours.

l *

In boiling methanol, d for decomposed material.

912 A. KUMAR et al.

39.02; H, 5.69; Sn, 38.38. Calc. for (CH,),Sn(CH,COCHCOCH,COCH,); Mol. Wt., 304; C, 39.39; H, 5.94; Sn, 38.92%.

Similarly the reactions of triethyltin-, tri-n- propyltin-tri-n-butyltin- and triphenyltin chlorides with 2, 4, 6-heptane-trione, 1-phenyl-1, 3, 5-hex- anetrione and 1, 5-diphenyl- 1, 3, 5-pentanetrione have been carried out. Their details of syntheses and identifications are given in Table 1.

Synthesis of bis [trimethyltin -mono (2,4,6-heptane - trionate)

Trimethyltin chloride (0.02 mole) taken in 20 cm3 of benzene was added to the benzene sus- pension of disodium salt of 2, 4, 6-heptanetrione (0.01 mole) in isopropanol. The reaction mixture was allowed to reflux for 4-5 hr to complete the reaction. Sodium chloride formed during the reac- tion was removed by filteration. From the filtrate binary benzene-isopropanol azeotrope was frac- tionated out between the temperature range 68-80°C and the compound was isolated by re- moving the last traces of solvent under vacuum.

Bis(trimethyltin) -mono (2,4,6_heptanetrionate) was found to be soluble in methanol and other polar solvents but insoluble in non-polar solvents. It is monomeric in refluxing methanol and non- electrolyte in nitrobenzene. Found: Mol. Wt., 449; C, 33.12; H, 5.46; Sn, 50.30. Calc. for [(CH,),Sn],(CH,COCHCOCHCOCH,); Mol. Wt., 467; C, 33.38; H, 5.60; Sn, 50.74%.

Likewise the reactions of triethyltin-, tri-n- propyltin tri-n-butyltin- and triphenyltin chlorides with disodium salt of 2, 4, 6-heptanetrione, 1 -phenyl-1 , 3, 5-hexanetrione and 1, 5-diphenyl- 1, 3, 5-pentanetrione in 2: 1 molar ratio have been carried otit and their analytical results are given in Table 2.

RESULTS AND DISCUSSION

The triorganotin mono (p, 6-triketonates) and bis(triorganotin)-mono (/3, S-triketonates) are ei- ther yellow-brown coloured viscous liquids or crystalline solids, soluble in common organic polar and non-polar solvents, except the bis-derivatives of 2, 4, 6-heptanetrione. They decompose around 35-45”C. Both 1: 1 and 2: 1 products are mono- meric in freezing benzene and non-electrolyte in nitrobenzene.

Infrared spectra of triorganotin-mono (fl, 6-triketonates) show prominent bands in the re- gion 3400-3200 and 170&l 500 cm - ‘. The former has been assigned to the vOH. The strong intensity bands around 1680-1650 cm- ’ are assigned to the free carbonyl group. The band around 1600 cm - ’ has been assigned to the coordinated carbonyl groups.‘pz3 The VC = 0 of the non-chelated carbonyl group is also slightly shifted in com- parison to those of free ligands, presumably due to the shift in keto-enol equilibrium.

However in the IR spectra of bis- triorganotin)-mono (j?, 6 -triketonates) marked lowering in VC = 0 without splitting have been observed, indicating thereby coordination of all the carbonyl oxygens to the central tins.23

The presence of metal-oxygen24 and metal-carbon is revealed by the presence of strong to medium intensity bands in. the region 730-600 and 590-500 cm -I, respectively. The presence of two bands in the latter region clearly reveals non-linear nature of -SnR, groups Tables 3 and 5.

The PMR spectra (Table 4) of triorganotin- mono (p, b-triketonates) reveal the presence of tautomeric methine signal at 6, 7.15-7.3 ppm. This signal is a far more shifted downfield than the one due to free ligands. Such a situation has emerged because of the delocalisation of n-electrons (I),

/R’ '\OH

” +” form cm)

Novel triorganotin(IV) derivatives of fl, 6-triketones 913

Table 3. Diagnostic IR bands of triorganotin-mono@ b-triketonates)

conpoud vc=o SC-l;‘0 Van an-o %I Sn-0 9aa Sri--- 98 Sn-c

R3sn K2i3cocHcocH2conr, 1

RICH 3

R = c2n5

R-n-C3'$

R -PC,%

R "6%

C?13coCli2coQi*coCn3

R3~'C6H5CCCHCOCli2COCH3)

RICH 3

R .C2H5

R -R=C3H,

R = "C&i9

R -'6%

c6H5cCCR2c0C%c-3

RICH 3

R . C2H5

R * g-C,H,

R . g-C H 45

R -'S%

c6%c-2c-2coc6%

1670a

16756

1660s

16508

16606

17156

1670~

167%

16706

1670s

1680s

17008

1670~

16SoaP

16758

167&n

1665m

1680s

1600s

16OSa

16OOb

15906

15958

720~ 670b

725~ 675b

71Ow 670-66Ob

7oOw 680s

715m 6651~

6208 52Oin

590w 525m

600m 540-510b

600~ 51Ow

610~ 540e

16OoW 7358 5SOb

16OCm 720m 670m

1590s 720s 66lBil

15908 700s 670m

16000 715s,ioom 670~

54Ou 4508

505m 5oOw

58Om 520m

61(ka 525~

6008,550~ SOOm,475m

1600m 720s 650~ 560~ 490s

15908 72&o 640m 54Qn 510s

15908 7358 66cw 580m 52@n

159Qn 710m 60&n 55Ow 470m

1600s 690s 620~ 55(ka 495w

Annotation: (I - ahharp, m = medium, b =hroad and Y -weak.

Table 4. PMR data for R,Sn(CH,COCHCOCH,COCH,) at room temperature

COUpOUlXl

CH3COcH2C00i2COCH3

@H3~3S"@H3COCHCOCH2COCH3)

chemical shift inKvalues

Aromatic -CH -CH 2 -CH;

5.20.5.7 3.55.3.85 2.l,2.45

7.15.5.8. - 2.00 5.4

(q-c4ng 1 3sn (~H~COCHCOCH~COEH~ ) - 7.3.5.70 - 1.80-2.40 5.22

(C6H5)3Sn(CH3CCCHC~2COCH3) 7.20-7.70 6.1.5.4 2.00-2.20

* tdethyl group at the terminal of the ligand molecule.

A. KUMAR et al.

Table 5. Diagnostic IR bands of bis(triorganotin)-mono(& d-triketonates)

9cz-o Yas M-0 21, sn-0 yas sn-c Y8 Sn-C

(CH3COCHCCCHCOCH3)

R-M 3

R - C2H5

R -.p-C3H,

R - “-c,Hg

R - ‘SH5

R -CH 3

R = C2H5

R - @3H7

R - r?'C4H9

R = ‘6%

RICH 3

R - C2H5

R - “-c3%

R = g-C,Hs

R = C6H5

160013 73om

1600s 740m

1600s 710m

16008 75om

16106 7308.7008

1600m

1600s

1630s

1610s

16006

725s

720s

7108

7208

7308.700s

159oa

1600s

1610s

16008

16008

700s

71Om

7101n

725s

720s

670b

670-6601,

680-670b

680s

660m

680111

670b

680s

69Om

680s

680m

670b

660m

680s

680m

6loV

6001~

610b

600~

530-520b

530-520b

51om

530-510b

520~

6OoW 5508

6OoW 540s

5808 51(ka

6OOb 5OOb

6OoW 55Ow, 5oow

5408

600b

6106

59ow

6OoV

Slow

52Qn

Slob

530-510b

5008

&ota+~onr s I aharp, m =mm%unr b -broad and w=wmk.

implying coordination of both the terminal and central carbonyl groups to the central tin.

The CH, signals were found at 6, 5.8 and 5.4 ppm, respectively is implying that the vinylic proton is under two magnetically non-equivalent environments, the “2” and “E” forms. These two forms are in equilibrium. In the “2” form the vinylic proton is nearer to the alkyl group (II) because of the shielding effect of the alkyl group while the peak appearing in the downfield region is attributed to the vinylic proton of “E” form in which it is deshielded (III).

The PMR chemical shift data of some of the bis(triorganotin)-mono (j?, 6 -triketonates) are given in Table 6. The methylene signals appearing at S, 3.5-4.3 ppm in the unchelated ligands,25 altogether disappear in the chelates, implying in- volvement of all the three carbonyl groups in chelation. The methine signals shift towards lower magnetic field as compared to free ligand, implying delocalisation of rr-electrons throughout the framework. Further appearance of two methine signals at 6, 7.15-7.5 and 5.75-6.0 ppm indicate two types of methine protons. In the former case

R I/

(R=olkyl group)

(Y)

(0 is phenyl)

Novel triorganotin(IV) derivatives of fl, a&ketones

Table 6. PMR data for [R,Sn],(/L 84riketonates) at room temperature

Compound chemical shift in&values

Aromatic -CH CH2 cn;

~C"3)3s~2@"3CocHcoQicoc"3) - 7.15.5.7s - 1.7-2.20

I ipc3n7 j3s~j2 (~"~C~~HCOCHC~CH~) - 7.20.5.95 - 1.95-2.30

c-- (n C4H9)3Sn]2~CH3COCHCOCHCOCH3~ - 7.5,6.05 - 1.90-2.40

~~~~~~~~~~~~~~~~~~~~~~~~~ 7.2-7.7 1.90-2.10

~~CH3)3Sn~2(C6H5cCCHCOC"COCH3) 6.8.7.4 6.0 - 1.80

[~pC3H7~3Sn~2(C6H5cOCHcOCHcWH3) 7.35.7.95 6.0 - 1.80

~WiJ)3sn]2(c6H5cOCHCOCHCOC6H5) . 6.8,7.35 5.90 - -

~~-c3H7)3Sn)2(c6H5coc~coc~coc6H5) 7.35,8.00 6.0 - -

915

* &thy1 group at the terminals of the ligand molecule.

one of the trialkyl tin forms a part of the chelated ring, embracing two oxygens of the central and terminal carbonyl groups, stabilized through the n-electron delocalisation, imparting quasi- aromaticity. 26*27 In such a situation the methine proton is deshielded (IV), allowing the formation of penta-coordinated tin, while the second tri- alkyltin is attached to the oxygen of the terminal carbonyl group and it is four coordinated.

Further in the complexes (V) of triphenyltin there is only one CH proton signal, implying that each of the triphenylstannyl groups attached to the two of the three carbonyl groups forming homo bimetallic complex. The explanation of this strange situation can be advanced on the basis of the - I effect of the phenyl group, resulting in the enhance- ment of the electron accepting property of tin(IV). As a result of this central oxygen becomes three- coordinated and on account of the ring current both the CH protons are rendered magnetically equivalent. The methine signal also merges into the those of the phenyl groups.

Acknowledgements-The authors are grateful to Prof. R. C. Mehrotra for encouragement, and to Prof. K. C. Joshi for providing necessary laboratory facilities.

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5.

6.

7.

8.

9.

10.

11.

12.

13.

14.

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