The crystal structure of bisnitrito-2,2'-bipyridylcopper( I I ) has been determined by X-ray diffraction methods and refined by a fuil-matrix least-squares procedure. The monoclinic unit cell space group P2Jc has dimensions a = 8.393, b = 10-080, c = 15.136 8, p = 110*04", for Z = 4. The copper atom is surrounded by a nearly square planar arrangement of the two bipyridyl nitrogen atoms at 1.98 .b, and an oxygen from each nitrite ion at 1.99 8. The second oxygen of each nitrite is then involved in weak co-ordination at a longer C u -0 distance of 2-49 8, the latter making an appreciable angle (32") with the normal-to-plane of the in-plane bonds. The molecular symmetry is C2 and the bipyridyl ligand is nearly planar, the twist about 2,2'-carbon bond being 3.2'.THE nitrite ion may co-ordinate to metal ions in essentially three ways: through the nitrogen atom forming the well-known nitro-complexes, through the nitrogen atom and one of the oxygen atoms thereby acting as a bridging group as in [Ni(H2NCH2*CH2*NH2)20NO]BF4,1 or through one or both oxygen atoms forming the lesser known nitrito-complexes. The distinction between nitro-and nitrito-co-ordination in nitrite complexes can be made on the basis of the anion i.r. spectrum.2 It has been suggested3 from i.r. studies of nitritonickel(@ complexes that it is possible to differentiate between mono-and bi-dentate nitrito-co-ordination. This has been substantiated from X-ray structure analyses of Ni(Me,N*CH,*CH,*NH,),(ONO)~ * and Ni-(Me,N*CH,*CH,*NMe,) ( ON0),.6 ~-The i.r. anion spectrum of the 2,2'-bipyridyl (bipy) complex Cu bipy(N02)2,6 with bands at 1372, 1150, and 844 cm.-l, is closely comparable with that observed (1365, 1160, and 840 cm.-l) for (Cu bipy,ONO)NO, in which the nitrite group is nitrito-co-ordinated and bidentate.7 On this basis it might be predicted that a similar arrangement of the nitrite groups is present in Cu bipy(NO,),. However, this would lead to large distortions in the copper atom environment. The X-ray analysis of Cu bipy(NOz), has been undertaken to determine its structure.

Complexes [Co(q-C5H5)L( CS3)] have been prepared (a) by the thermal reaction of CS2 with [Co-(q-C5H5) (CO)L], or [ C O ( ~-C ~H ~) ( C O ) ~J and L (L = tertiary phosphine or organoisocyanide only), or ( 6 ) from [Co(q-C5H5)(L)12] and Na2[CS3] in dichloromethane solution (L = tertiary phosphine, phosphite, arsine, or organoisocyanide). A variant of ( b ) , the reaction of Na[S2COR] ( R = M e or Et)with [Co(q-C5H5) (L) 12], has been used to prepare the dithiocarbonate complexes [Co(q-C5H5) (L)-(CS20)]. The i.r. and 'H n.m.r. spectra of the complexes have been measured and are assigned. They are consistent with molecular structures in which the CS2Y2-ions (Y = 0 or S) chelate t o cobalt via the t w o S atoms; this has been confirmed unambiguously for [Co(q-C5H5)(CNBut)(CS3)] by an X-ray diffraction study which shows that the co-ordination about Co is of the well known pseudooctahedral, ' piano-stool ' type. The structure was solved by the heavy-atom method and refined b y least squares to R = 0.074 for 1 593 non-zero unique reflections. Crystals of the compound are monoclinic, space group P2,/c, with a = 9.085( 4), b = 12.386( 5), c = 12.997(5) A, and B = 107.7(1)' for 2 = 4. The unco-ordinated S, atoms of the CS3 ligands are very basic and with electrophiles, E, form adducts containing S, -+ E bonds; Me1 gives [Co(q-C5H5)(PBun3)(S2CS,Me)]l and [Co(q-C5H5)l(S2CS,Me)], mercury(tt) halides form [Co(q-C5H5)(PBun3)(S2CS;nHgX2)] (X = CI, n = 2; X = Br or I, n = l ) , and l2gives [Co(q-C5H5) ( PPrn3) (S2CS,l)] I. The v( C-S,) vibrations of these adducts have lower frequencies, and their v(C-S,) vibrations (S, is the co-ordinated S atom) have higher frequencies, than d o their trithiocarbonate precursors. The dithiocarbonate complexes also form adducts with electrophiles but the unco-ordinated 0 atom, 0,, is only weakly basic. Consequently Me1 fails but MeS03F is successful in

The crystal structure of nitritobi~-2,2'-bipyridylcopper( I I) nitrate has been determined by X-ray diffraction methods using three-dimensional data. The complex crystallises in the monoclinic unit cell, space group P21/n, with dimensions a = 11 .I 01, b = 12.058, c = 15.385 8, and p = 99" 10'. and Z = 4. The copper(l1) ion is six-coordinate with the two colinear short CU-N bonds a t 1-99 A, two intermediate length CU-N bonds of 2-08 A a t 103" to each other, and two long Cu-0 (2.24, 2.33 8) from the chelating nitrite group. The environment about the copper( 11) ion is best regarded as a cis-distorted octahedron and the approximate symmetry of the [Cu bipy2-ONO]+ cation is C2.THERE is no crystallographic evidence in the literature that the copper(I1) ion can form complexes with a cisdistorted octahedral stereochemistry. The [Cu bipy,-(OH2),l2+ cation (bipy = 2,2'-bipyridyl) is said to exist with this stereochemistry in aqueous solution because steric factors prevent the two bipyridyl ligands assum-F. Stephens, I. 31. Procter, D. E. Billing, B. J. Hathaway, and P. Nicholls, unpublished results.

The crystal structure of the title compound has been determined by X-ray diffraction methods from three-dimensional counter data. The structure was solved by Patterson and Fourier methods and refined by least squares to R 0.064 for 1 307 independent reflections. The complex crystallises in the orthorhombic space group Pnan, with dimensions a = 14.376 f 0.027, b = 14.833 f 0.028, c = 23.339 f 0.061 8, and Z = 8. The cation has C2 symmetry and the environment about the copper atom is trigonal bipyramidal. The trigonal plane is formed by a nitrogen atom from each bipyridyl ligand (Cu-N 2.08 8, subtending an angle of 123" a t Cu) and the chlorine atom (Cu-CI 2-36 A). The remaining two bipyridyl nitrogen atoms occupy axial positions (Cu-N 1.98 8) and the direction between these two nitrogen atoms lies 11.5" from the normal to the trigonal plane. The cations pack in sheets perpendicular to c a t z = 6 and I . The anionic chlorine atom and the water molecules are disordered in the channels between the cation sheets.THE solid-state visible absorption spectra of [Cu(bipy),I]X (X = I or C10, and bipy = 2,2'-bipyridyl) are similar and the crystal structure of the former complex has shown the presence of the five-co-ordinate [Cu(bipy),I] + cation,, in which the copper atom possesses a stereochemistry intennediate between trigonal-bipyramidal and square-based pyramidal. However, for the complexes [Cu(bipy),Cl] X the solid-state visible absorption spectrum for X = C10, is sufficiently different from the spectra for X = Cl,6H20 and PF,,H,O t o suggest the possibility of the presence of different stere0chemistries.lThe crystal structure of [Cu(bipy),C1JC1,6H20 was undertaken to determine the stereochemistry of the copper atom. EXPERIMENTAL Crystal Data.-C2,H,,C1,CuN,0,, M = 554-9, Orthorhombic, a = 14.376 -+ 0.027, b = 14.833 f 0.028, c = 23.339 f 0.061 A, U = 4976.8 Hi3, D, = 1.47 (by flotation),

No abstract