Kinetics of styrene emulsion polymerization in the presence of montmorillonite

Printed in Great Britain 0 1993 Pergamon Press Ltd

OSMIUM(VI) COMPLEXES OF SULPHONYL AMID0

LIGAND. CRYSTAL STRUCTURES OF

WA-HUNG LEUNG*

and

ERNEST KIN-FAI CHOW

Chemistry Department, Hong Kong University of Science and Technology,

Clear Water Bay, Kowloon, Hong Kong

and

SHIE-MING

PENGt

Department of Chemistry, National Taiwan University, Taipei 10764, Taiwan, R.O.C.

(Received 8 February 1993 ; accepted 5 March 1993)

Abstract-Interactions

of [PPh4]2[0s02C14] and [Bu”,Nl[OsNCl~] with LiZL [H2L = 1,2-

bis(p-toluenesulphonylamido)benzene]

gave binuclear osmium(V1) compounds (PPh,),[Osz

04LZ(p-OH)d

(1)

and OS~N~L&-OH)~ (2), respectively. The structures of both compounds

have been determined by X-ray crystallography. The crystal structure of the [OsZ04LZ@-

0H),12-

anion contains two trans-0s02(L)

units bridged by two OH groups; the

OS-0(0x0)

bond length is ca 1.74 %i. The crystal structure of 2 contains two OsN(L) units

bridged by two OH groups

; the Os-N(nitrido)

bond length is ca 1.56 8.

Multianionic chelating ligands are of current inter-

est because they can stabilize metal ions in high

oxidation states. High-valent metal complexes with

deprotonated

amido ligands, e.g. those of man-

ganese(V),’ iron(

cobalt(IV),3 nickel(III)4 and

copper(III),’ are well documented. However, there

are relatively few studies on complexes of sulphonyl

amido groups. As the sulphonyl group is more elec-

tron-withdrawing

than the carbonyl group one

might expect that sulphonyl amido ligands can be

deprotonated more readily and hence could display

interesting coordination chemistry. To this end we

set out to investigate the chemistry of complexes

containing

chelating sulphonyl

amido ligands,

e.g. bis-(toluenesulphonylamido)benzene

(H,L), as

shown in Fig. 1. The unique features of the ligand

H2L are

: (a) it is bidentate and dianionic ; (b) it can

stabilize highly oxidizing metal centres due to the

* Author to whom correspondence should be addressed.

t Author

to whom inquiries concerning X-ray crys-

tallography should be addressed.

strong a-donating deprotonated

sulphonyl amido

groups

; and (c) it is sterically bulky. Recently, the

crystal structures of some copper complexes of H2L

have been described.6 We herein report the synthesis

and crystal structures of two osmium(V1) com-

pounds of the ligand.

EXPERIMENTAL

The ligand H2L,& IpPh4]2[Os02C14]7 and [Bu”,N]

[OsNC14]* were prepared according to the litera-

ture procedures. Organic solvents were purified by

standard methods and distilled before use. ‘H

NMR spectra were recorded on a JEOL EX 400

spectrometer. Chemical shifts (6) were reported ref-

erenced to Si(CH,),.

IR spectra (Nujol) were

Fig. 1.

1635

1636 WA-HUNG LEUNG et al.

obtained on a Perkin-Elmer

1600 FT-IR spectro-

photometer. Elemental analyses were performed by

MEDAC Ltd (Middlesex, U.K.).

Preparation of

[PPh,]2[0s204Lz(p-0H)Z]

(1)

To a suspension of H2L (0.4 g, 0.96 mmol) in

THF (20 cm3) at -40°C was added 2 equivalents

of Bu”Li

(ca

1.25 cm3 of a 1.6 M solution in

hexanes). The resulting mixture was warmed to

room temperature and stirred for 1 h. To this solu-

tion was added ~Ph&[0sOzC14] (0.51 g, 0.5 mmol)

under nitrogen and the reaction mixture was stirred

at room temperature overnight. After the removal

of volatiles the dark red residue was extracted with

acetonitrile/ether.

Slow evaporation of the extract

at room temperature afforded red crystals, which

were collected and washed with ether (yield 0.25 g).

‘H NMR (CD,CN)

: 2.34 (s, 12H,p-CHJ,

5.96 (br,

s, 2H, OH) and aromatic protons. IR (Nujol)/cn-

’ :

v(O-H)

3437; v(S=O) 1152, 1108; ~(0~0,) 859.

Found: C, 53.2; H, 4.0; N, 3.3%. Calc. for [OsZ

Cs8H78N40,4P2S4]: C, 53.2; H, 4.0; N, 2.8%.

Preparation of

OS~N~L~(~-OH)~ (2)

The lithium salt of HIL was prepared as for

[OS~O&OH)~]~-. To a THF solution of Li2L (pre-

pared from 0.41 g H2L and 1.25 cm3 Bu”Li) was

added [Bun4NJ[0sNC14] (0.29 g, 0.5 mmol). The

reaction mixture was stirred overnight and evap-

orated to dryness. The dark yellow residue was

extracted with THF. Careful addition of hexane to

the extract afforded the crude product, which was

recrystallized from THF/ether/hexane

to give yellow

crystals (yield 0.2 g). ‘H NMR (CD&N) : 2.29 (s,

6H, p-CH3); 6.28, 6.83, 7.06, 7.81 (all broad

singlets, 12H, aroamtic

protons).

IR (cm-‘):

v(O-H)

3450; v(S=O) 1150, 1126; v(OsN) 986.

Found:

C, 61.5; H, 5.5; N, 11.0. Calc. for

[OS~C&,H~~N~O,&]: C, 62.3; H, 4.9; N, 10.9%.

X-ray crystallography

Diffraction measurements were performed on an

Enraf-Nonius

CAD-4 diffractometer. Lattice par-

ameters of

1

were obtained from 25 reflections with

20 angles in the range 17.00-21.00”, whereas cell

dimensions of complex 2 were determined from 25

reflections with 28 angles in the range 11.06-20.40”.

All reflections were collected for Lorentz, polar-

ization and adsorption effects. All data reduction

and refinement were performed using the NRCC-

SPD-VAX packages. The structures were solved

by direct methods and refined by full-matrix least-

squares

; all non-hydrogen atoms were refined with

anisotropic thermal parameters. Both complexes

1

and 2 crystallize in the triclinic system with the

space group

Pi.

Hydrogen atoms on the organic

ligands were calculated in idealized positions and

were included in the structure factor calculation.

The combined data collection and refinements are

given in Table 1. Selected bond lengths and angles

for complexes

1

and 2 are given in Tables 2 and 3,

respectively.

Table 1. Experimental data for the X-ray diffraction studies” Compound Formula Crystal system Space group 0 (A) b (A) c (A) a 0 B (“) Y (“) v (A’) Mol. wt Z & (g cm- ‘) p(Mo-&) (cm- ‘) Transmission factors

R;R,,,b

1

C90H78N4014P20s2.tMeCN),

Triclinic Pi (No. 2) 12.867(5) 14.418(4) 14.621(4) 66.69(3) 64.69(3) 64.48(3) 2137(l) 2008 1 1.608 31.7 0.6961.00 0.043 ; 0.055 2 C,oH,~N,G,&Gsz- (THF)*2(H,O)- 1/2(Et,O) Triclinic Pi (No. 2) 11.363(8) 14.289(g) 18.580(7) 109.55(5) 102.62(3) 90.23(5) 27,656(2) 1270 2 1.697 48.0 0.745-l .oo 0.062 ; 0.062

0 Features common to all determinations : I(Mo-K,) = 0.7107 A; temperature = 297 K. b

R = Z~~Fo~-~Fc~~/E~Fo'ol,

R,

= ~w(F,-F,)~/ZW~~~]"~.

OS”’ complexes of sulphonyl amido ligand

Table 2. Selected bond lengths (A) and angles (“) for the [Os204Lz@-

OH),]‘- anion

1637

Os-o(

1)

1.740(6)

Os-O(2)

1.747(7)

Os-O(3)

2.051(6)

OS-N( 1)

2.022(6)

0(1)--0s--o(2)

O(l)-Os-O(3)

0(3)-Os--o(3’)

0(3)-Os-N(1)

0(4)_-S(ltiN(l)

Os-O(3)---Osa

OS-N(l)-S(1)

N(l)_-C(l)--C(2)

175.7(3)

86.7(3)

71.3(2)

175.7(2)

110.8(4)

108.7(3)

123.9(4)

129.1(7)

S(lW(4)

1.428(7)

8(1)-N(l)

1.646(6)

N(l)_-C(l)

1.40(l)

OS-N(l)-C(l)

O(l>--os-N(1)

N( 1 )-OS-N(~)

0(3)-Os-N(2)

N(l)_-S(l>-C(7)

O(4)-S(lFN(l)

0(4)--8(1)-C(7)

N(l)-C(l)--C(6)

118.4(5)

92.5(3)

78.3(3)

105.9(2)

106.6(3)

110.8(4)

107.7(4)

114.2(7)

RESULTS AND DISCUSSION

Interaction

of [PPh&[0s02Cl,]

with 2 equiv-

alents of the lithium salt of H,L [H2L = 1,2-bis(p-

toluenesulphonylamido)benzene]

in THF gave the

air-stable binuclear hydroxo-bridged

osmium(VI)-

dioxo compound

(l),

isolated as its [pPh,]+ salt. A

monomeric compound could not be obtained even

when excess ligand was used, presumably because

the ligand is too bulky for formation of a planar

bischelate complex. The IR spectrum of

1

does not

show any sharp N-H

band, indicating that the

sulphonyl amido group is in the deprotonated form.

The broad band near 3470 cn-

’ can be assigned to

the v(O-H) stretch. The Os=O stretch at 845 cm-

’

is within the range expected for trans-0~0~ com-

pounds.

The binuclear structure of

1

was conlirmed by

an X-ray diffraction

study. A diagram of the

[OszO,L&OH),]*-

anion is shown in Fig. 2;

selected bond lengths and angles are given in Table

2. The geometry around each osmium is best

described as octahedral with the two 0x0 groups as

axial ligands and L and two hydroxo groups as

equatorial ligands. The two truns-OsOzL units are

bridged by the two hydroxo

ligands with the

OS-O(H)--OS’

bond angle of ca 108.7”. A similar

structure has been observed for the binuclear oxo-

bridged 0~~O~py+~ The Os-O(oxo)

bond lengths

(ca 1.74 A) are normal by comparison with trans-

osmium(W)-dioxo

compounds.

The Os-N(sul-

phony1 amido) bond length of cu 2.03 A is similar

to that for Os-N(amido)

found in a related

osmium(VI)-nitrido

compound of a tetradentate

amido ligand. lo Of note, the four toluenesulphonyl

groups of the ligands adopt a “two-uptwo-down”

geometry.

Treatment of [Bu”&J[OsNCL,] with 2 equivalents

of Li2L gave the neutral dimeric osmium(VI)-

nitrido compound 2. Again, the steric bulk of the

ligand L precludes the formation of the monomeric

bischelate complex. The presence of the bridging

hydroxo group is indicated by the broad IR band

at 3450

cn- ‘.

The OS-N stretch at 986 cm-’ is

Table 3. Selected bond lengths (A) and angles (“) for 0s2N2L,(p-OH),

(2)

Os( 1)-O(9)

1.99(2)

Os( l)-N( 1)

1.97(2)

OS(~)-N(5)

1.52(2)

OS(~)-N(6)

1.61(2)

0(9)-0s(1)-0(10)

74.5(7)

0(9)--Os( l)-N( 1)

92.4(7)

0(9)-Os(l)-N(2)

140.2(7)

0(9)-Os(l)--N(5)

110.0(9)

N(l)-Os(l)---N(2)

85.6(7)

N(l)-OS(~)-N(5)

113.1(9)

N(2)-Os(l)--N(5)

109.5(9)

N(l)_-C(l)_-C(6)

112(2)

WI-W)

1.60(2)

S(l>--o(l)

1.46(2)

N(l)-C(1)

1.47(3)

W)-W)_W)

O(l)-8(1)----c(7)

W-W-c(7)

Os(l>--o(9)-0s(2)

OS(~)-N(l)-S(1)

OS(~)-N(lW(1)

N(lW(l)_-C(2)

S(l)--C(7)--c(8)

105(l)

108(l)

106(l)

104.2(7)

124(l)

116(2)

126(2)

120.7(8)

1638 WA-HUNG LEUNG et al.

Fig. 2. A perspective view of the [Os,O,L&-OH)$- anion.

normal for nitrido compounds. The ‘H NMR spec-

trum of 2 is consistent with the solid-state structure.

The structure of 2 has been determined by X-

ray crystallography.

An ORTEP drawing of 2 is

shown in Fig. 3 and selected bond lengths and

angles are given in Table 3. The geometry around

each osmium is square pyramidal with the nitrido

group as an axial ligand. The two Os(N)L units

are bridged by the two :hydroxo ligands with

the two nitrido ligands on the same side. The

Os(l)---O(H)--Os(2)

bond angle of 104.2” and

Os-N(amido)

bond length of 1.973 A are similar

to those for

1.

The Os-N(nitrido)

bond length

is normal for osmium(W)-nitrido

compounds.

’ ’

It might be noted that this is the tirst structure of

a binu~l~r osmi~-~t~do

~ompo~d.

The reactivity of these two osmium complexes is

being studied.

Acknowledqemertts-We thank the Hong Kong Uni- 5. S. T. Kirsey Jr, J. A. Neubecker and D. W. versity of Science and Technology, Hong Kong Research

Grants Council and the National Science Council of the Republic of China for support. W.-H.L. thanks Prof. Cm-Ming Che for helpful discussions.

6.

7. 8.

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