S T R U C T U R E OF T W O C O M P L E X E S O B T A I N E D BY THE R E A C T I O N

OF R U T H E N O C E N E W I T H M E R C U R I C H A L I D E S

A. I . G u s e v a n d Y u . T . S t r u c h k o v

In order to answer the question whether or not a direct bond exists between the ruthenium and mercury atoms in the compounds of ruthenocene with mercuric halides, namely [(Tr-C~ts)zRu]z. 3HgC1 z (I)* and (7r-CsHs)zRu �9 HgBr~ (oII), we carried out an x- ray study of these compounds. The unit ce l l parameters are : I) a = 24.84, b = 35.64, c = 7.74

A, ), =90 ~ ddet= 2.83, dca l c=2 .79 g / c m 3, N=8, space group B2/b; II'~) a =14.679, b=11.518, c - 9 . 0 4 7 /~, ), =

120.61 ~ dale t = 2.92, dcalc = 2.85 g / c m z, N =4, space group P21/b.

Using copper radiat ion, we obtained with a KFOR camera the hk0 - hk3 scans (about 1200 independent nonzero

reflections) for compound I and, using copper radiation and the Weissenberg method, we also obtained the hk0 - hk6 scans (about 1000 independent nonzero reflections) for compound II. The intensities were determined visually.

The structural analysis was carried out according to the Patterson-Fourier series using standard methods.:~ To date i t proved possible to locate only the heavy atoms (ruthenium, mercury, and the halogens); the precise de te rmi -

* Obtained by the recrysta l l izat ion of the 1 : 1 complex, i .e . , of ( ~r-CsHs)zRu �9 HgC1 z from organic solvents.

"~The parameters were determined with the dif f ractometer DRON-1. SAIl calculat ions were carried out according to the programs developed at the Branch of the Institute of Chemica l

Physics, Academy of Sciences of the USSR, by B. L. Tarnopol 'skii , V . I. Andrianov, and Z. Sh. Safina.

/ ~,u(O

e ~ tp) I / /

I • I I

2,60 ~./' 2,50 oCL(5)

d

\ \

Fig. 1 "" s ~g(J)

Institute of Elementoorganic Compounds, Academy of Sciences of the USSR, Moscow. Translated from Zhumal Strukturnoi Khimii , Vol. 12, No. 6, pp. 1121-1122, November-December , 1971. Original ar t ic le submitted July 27,

1971.

I @1972 Consultants Bureau, a division of Plenum Publishing Corporation, 227 West I7th Street, New York, N. Y. 1001I. All rights reserved. This articie cannot be reproduced for any purpose whatsoever ;c'ithzut per,.~i~s~an of the pub!i~her. ,4 cop)" of this article is available from the publisher for $!5.00.

I

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Ru ( . ) Br{~) o Brp~

/Z_ 2

Br(O Br(z~ Oa~ Fig. 2.

nation of their position was carried out by the 1east-squares method

up to R=22% in I and up to 28% in II.

The outstanding featuresof the structure I are the side chains shown in Fig. 1. Each of the two separate Ru atoms is found within a short

distance of one of the Hg atoms. These distances (2.60 and 2.65 ~, respect ively) are even smal ler than the sum (2.81 A) of the tetrahedral Hg radius (1.48 A)and the octahedral radius of ruthenium (1.33 ~), so that the fact of the bond formation is beyond question. The bond lengths de t e rmined above are also s imilar to the O s - H g bond length (2.577 A) in the compound OsC12(HgC1)(NO)(PPH3)2* which is some-

what shortened, according to the opinion of the authors.

The "crys ta l l iza t ion" molecule of HgC1 z (corresponding to the Hg (3) atom) is of the bridge type,and the tetrahedral coordination number in this molecule is comple ted by the C1 atoms bonded to the Hg atoms (1) and (2). The la t ter have trigonal and octahedral coordinations, respect ively . Among the 5 chlorine atoms coordinated with the Hg (2) a tom, only one, namely C1 (5), which is found in the trans position with respect to the Ru atom, forms the covalent bond H g ( 2 ) - C I ( 5 ) . The remaining chlorine atoms, however, which complete the octahedral coordi-

nation sphere of the Hg(2) atom are more strongly bonded to the Hg(1) and Hg(3) atoms as well as to the trans- l a t iona l ly ident ica l Hg (2) a tom. An addi t ional C1 a tom (not shown in Fig. 1) is not coordinated with one of the meta l atoms and apparent ly fulfills the function of a "lone n anion. Thus the formula I should be rewritten as

{[(~-CsHs)2RuHgC12I:[HgC12] X [(a-CaH@2RuHgC1]+}l~oC1-.

The direct bond Ru-Hg with the length of 2 .74~ was also found in the structure !I (Fig. 2). The molecules are combined by the bridging Br atoms into dimers placed in the center of symmetry, thus causing the Hg atom to assume a somewhat distorted te t rahedral configuration.

Further ref inement of the structures (I) and (II) continues with the object ives of determining the carbon atom positions and of refining the in te ra tomic distances. The basic question, however, concerning the existence of a direct bond between the ruthenium and mercury atoms may be considered as defini tely answered.

The authors wish to express their gratitude to S. P. Gubin for suggesting the subject of this study and for providing the mater ia ls .

*G. A. Bentley, K. R. Laing, K. R. Popper, and L M. Waters, Chem. Commun., 998 (1970).

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