84
Table IV. Weighted Least-Squares Planes5 Plane 1. 2. 3. 4. 5. 6.
Equation
NiNzNsN4 CiNiCaNa CzNzCaNh
Angles between planes, deg
0.55742 = 1.552 ++ 0.44032 = 0.862 ++ 0.62892 = 2.374 0.32502 = 1.230 + 0.40262 = 3.675 + 0.82062 = 6.906
0 . 1 1 1 9 ~- 0 . 8 2 2 6 ~ 0 . 2 3 3 8 ~- 0 . 8 6 6 9 ~ 0 . 0 2 3 7 ~- 0 . 7 7 7 1 ~ - 0 . 1 3 6 0 ~ - 0.93597 0 . 5 9 1 9 ~- 0 . 6 9 8 6 ~ -0.5686~ 0.0578~
C11-Cl6
CZl-cZ6 Cai-Cas
+
Distances of Atoms from Planes,b
1
I
1
( 6 ) 7.1 (7) 117.1 (7)
J
A
1. N1, -0.004; N2,0.004; Na,0.003; Nd, -0,004; Rh,0.1256; 01,-0.108; 0 2 , -0.125; 08,0.006; 0 4 , -0.025; Ci, -0.210; -0.162: Cz. -0.204: CA.-0.128 2. N1, 0.001; Na, -0.001; C1, -0.002; C8, 0.002; Mel, 0.075; Mea, -0.026; 01,-0.133; 08,-0.033; Rh, -0.144 3. Nz, 0,006; N4, -0,005; C2, -0,017; C4, 0.016; Mez, -0.217; Me4, 0.021; 02,-0.146; 0 4 -0.053; , Rh, -0.061 4. til, -0.012; ciz, 0.009; cia, 0.003; Cia, -0.020; Cia, 0.008; c16, 0.011 5. Czl, 0.006; Czz, -0.017; C23, 0.014; Cz4, 0.005; C Z ~-0.017; , Cz6, 0.009 6. C31, -0.002; c32, -0.002; C33, 0.003; C34, 0.002; C35, -0.007; c36, 0.006. I
Cz,
.I
The orthogonal coordinates (x,y,z) are directed along the crystal axes a, 6, and c * , respectively, and are in Pngstroms. The weight given to each atom i in forming the planes is w i = [ U U ~ ~ ~ U ~ ~ C* UAverage ~ ~ ] - esd's ~ ~ ~ of . atomic positions are Rh, O.OOO4; N, 0.004; 0, 0.004; C1-C4, 0.006; Me, 0.008; cIl-cI6, 0.008; Czl-C2e, 0.007; c31-c36, 0.007. 0
(A):
Table V. Intermolecular Contacts Less than van der Waals Radii
bridging carboxylato groups can be compared, such a constraining effect is at best slight. Thus the Mo-Mo distances in Mo2(O2CCH& and MozCls4- are 2.11 Molecule A Molecule B Distance, A and 2.14 bl, r e ~ p e c t i v e l y . ~ ~Again, ,'~ the Re-Re c1 c 1 3 3.695 (7) distances i? Rez(0ZCC6H6)4C1Z and RezCla2- are 2.235 0 3 Mel 3.364 (8) and 2.241 A, respectively.20~21It therefore seems un0 3 Mez 3.258 (8) 3.89(1) Me2 Met likely that the Rh-Rh distance in the acetate is shortened 3.99 (1) Me2 Me4 to any significant extent over a hypothetical case where no bridging carboxylates are present. Acknowledgment. We thank Dr. Alan S. Parkes for to their specific bonding requirements. Thus distances assistance with the intensity data collection, and the from 2.11 8, [ M O ~ ( O A C )to~ ] 2.72 ~~ A [CU~(O~CH)~National Science Foundation for funds used t o purchase NCS2-]18 have been observed. Moreover, in several the automated diffractometer. cases where isoelectronic systems with and without
--
Atoms
-
(17) D. Lawton and R. Mason, J . Amer. Chem. Soc., 87,921 (1965). (18) D. M. L. Goodgame, N. J. Hill, D. F. Marsham, A. C. Skapski, M. L.Smart, and P. G . H. Troughton, Chem. Commun., 629 (1969).
(19) J. V. Brencic and F. A . Cotton, Znorg. Chem., 9, 346 (1970). (20) M. J. Bennett, W. I
