IR study of molecular structure and conformation of μ-vinylidene Mn-Pt complexes

Journal of Molecular Structure,293 (1993) 8l-84 Elsevier Science PubIishers B.V., Amsterdam

IR STUDY OF MOLECULAR STRUCTURE OF JJ-VINYLIDENE Yn-Pt COYPLEXES

A. I. Rubaylo”, A. B. Antono”ab,

0. G. Senotrusovb, A. A. Johanssonb,

81

AND COEFORYATION

N. I. Pavlenkob, P. V. AVramOVa

S. V. Kovalenkob,

aKasnoyarsk State University, 79 Svobodny Prosp., 660062 Krasnoyarsk, Russia b Institute of Chemistry of Natural Organic Materials, Siberian Branch of the!,Russian Academy of Sciences, 42 K. Marx Str., 660049 Krasnoyarsk, Russia Based on the experimental data for Mn and Pt M-vinylidene complexes existence of spatial isomers has been shown. Mechanism of their formation. and influence of Pt atom ligand surroundings on the given process are discussed. 1.

INTRODUCTION

From the moment of synthesis Mn and Pt vinylidene complexes of the whole formula

isomers. The attempt makes these problems. 2.

present paper to elucidate

RESULTS AND DISCUSSION

number p-vinylidene

of Mn and Pt complexes I-VI (Table 1.) has been studied in liquid and solid phase at different temperatures by IR spectroscopy in the 2200-1600 -1 cm region where these complexes have intensive absorption bands, conditioned by stretching vibrations of CO A

attract attention of investigators by their chemical properties. There is a number of publications on these probletis [ 1-41. Nevertheless some aspects considered.

still demand to be In particular there is no similar data on the structure of complexes and possibility to form spatial 0022-2860/93/$06.00

@ 1993 Elsevier Science Publishers B.V.

groups The region of their deformation vibrations about 650 cm-’ have been considered also. The of attribution absorption bands in 2200-1600 All rights reserved.

82

Table 1 The spectral complexes

characteristic in

of

KB~ matrix

Ligand

at

the

V,

cm-l

a

WW2cH2

48

1874 1749 1902

15 18 35

1765

71

b

1903

a

1751 1933

9 10 15

1840

17

1911 1821 1926

37 61 39

1837

36

1933 lY68 192.5

17 17 10

1832

8

1926 1838 1929

35 40 16

1835

11

1913 1835

15 43

a b a

‘(OPri)3 b a

PPh3 b

cm

-

at

-1

the

temperature

region

in

detail

is

no need

has [5], to

discussed

therefore

are

there

attention

on

it. spectrum the

of

the

obtained

characteristics

substances

in

for solid

phase

given

studied

Cont.

of

isom.

77O

85%

66O

15%

75O

75%

87’

25%

68O

30%

85’

70%

66O

40%

89O

60%

74O

15%

76O

85%

67’

40%

85O

60%

in

CO

of

in

solutions

of

the

For

all

composite lines

in

conditioned of

solid

1.

spectral

region

availability both

Table

complexes

structure 6

Some

9

25’C

been fix

-190OC

cm-l

1756

b

*

G1/2,

39

a

PPh3

temperature

1898

b

PPh3

Cp(CO)2MnPt(+C=CHPh)L1L2

isomer

phase organic

and

by mixture in solvents

the

83

has

In established. however case,

been

latter broadening doesn’

of

t

absorption

allow

isomers difference

in

correct into

their complexes, Here

determined the

group

been

been

conditions

the

been

example

complex

I up

minutes

the

pair

with

of

va,

15

of

co

growth

of

fragment

intensity 1756

and at

in quick

the

at

the

decrease

of of

solution

methylene

chloride

recrystalization

of

the

given

molecule

groups Pt

isomer

structure rb

through

Owing form

fragment change

as

it

unsensitive ligand

of

analogous

apparently well,

to obtains

The does

one

Mn(CO12 atom in

plane bond.

by of

of

by

the

This

explained

coordination

surrounding.

for

despite atom.

Pt

possibly

semi-bridged

and ligand

Mn-Pt.-vinylidene

to

bands.

cm-’

content

surrounding

CO

6

different

during

cm-l

angle

relative

strict

1748

and

of absorption

smaller

bands,

the

bands

almost Of

narrow

of

occurs

adequate

its

100’~

have

vibrations

is

heating

Via

shows

frequencies

identical

fact

absorption

frequencies

substance

at

to

in

shown.

intensity

1874

Further

is

[j].

isomers

the

physical

experimentally

for

1898

by substance

of

Of

IIIa,

their

conformers

between

determined

Thus

Of

as

spectrum

OF

stretching

evaluated

existence

equilibrium

and

that

bond

complexes

analysis

distinguished

12)

existence

I-VI

groups, The

the

of

CO

has

rotation

the

of

Of

about

supposition

Mn-C vinylidene

direction difference

processes

CpMn(C0)2

characteristics

the

identical

observed the

The

also.

has

one.

initial

d

indicating

conformers

the

ang1.e

bonds

structural

to

the

and

between

bands

isomers

ratio

has

isomers

between

the

distribution

absorption

conditioning

pressed

spectrum

of

around

been

obtained

intensity

fragment

have

for

KBr matrix.

the

confirm

structure.

data

be

The

evaluate

enough

obtained

with

between

to

and

the

determine

ratios

quantitative

it

bands

to

can

the

with

exist the

84

dif’ference

that

(PPh2 )2CB2 impossibility

deformation the

determines coordination for

Pt

the

bin and atom

of

especially bond

In

consequence saturation

electronic Mn(cO)2

fragment

frequencies groups

group

by isomer

of Pt

atom with

is d

in

The complexes

to

being

stable

are

for

them

absorption

at larger bands

different

by Pt

1.

of type

coordination

There

is

group a

mobile

shifted

by

and

A. B. An tonova e.a.

acta.,

No.

Inorg.

,

96 (1985)

1. and

A. B. Antonova acta.

,

Inorg.

105

(1985)

e, a. ,

No.

153. 3.

that’s

why

beadths

OF

complexes

by

factors.

Chim.

khim,

vibrations

of

S. V. Kovalenko

ligand

of

spatial

characterized

equilibrium

Chim.

to

and

around

carbonyl

atom.

the

e.a.

Pt,

fragment

form

semibridged

mobile

frequencies

fragment

type

more

sensitive

substitution

different

S. V. Kovalenko

therefore

and

internally

being

are

CO-group

coordination

bond

isomers, of

to

rotation

CpMn(CO)2 Mn-Cv in

2.

semi-bridged

of

of

case

less

due

vinyfidene

REFERENCES

isomers

have

Pt

shown

CO

reasons.

other

and

complexes

been

angle.

due

mentioned

Mn

enter

of

this

different

has

specific

large

complexes

it

isomer

semi-bridged

characteristics

above

CO

“strict”

Ivb

Frequency naturally

of

decrease.

and

coordination

and

vibrations

respectively IIb

of

increases

of

For

they

in

semi-bridged

Pt-co*.

CONCLUSIONS

Thus that

optimal

resulting

formation

strong

for

of

Pt,

and

3.

united plane

vinylidene,

characteristic.

dispersion Mn(C0)2 at are

4.

A. B. Antonova Izv.

,

and

ser.

SSSR.

AN

No 4 (1982)

S. P. Gubin

95. and

A. A. Johansson

A. B. AntOnOVa

e.a.

SSSR.

khim.,

2.

Ser.

AN

Izv.

, I

(1987)

56. 5.

A. I. Rubaylo Khimia.

and

0. G. Senotrusov ,

e. a.

No 24

,

(1991)

Metaloorg. 465.