Crystal Structure and Electronic Properties of Ammine[tris(2-aminoethyl)amine]copper(i~) Diperchlorate and Potassium Penta-amminecopper( 11) Tris( hexaf luorophosphate)By M a r y Duggan, Noel Ray, Brian Hathaway,' and (in part)

The low-temperature crystal structure of [NH,],[Cu(OH,),][SO,],(1 ) has been determined by X-ray diffraction methods at 203 and 123 K, in the monoclinic space group, P2, /a. The structure changes very little with temperature, except with respect to the geometry of the Cu06 chromphore which becomes more elongated rhombic octahedral with decreasing temperature (298, 203, 123 K) : Cu-0(7) 2.21 9(5), 2.250(2), 2.278(2) ; Cu-O(8) 2.095(5), 2.041 (2), 2.01 2(1) ; Cu-O(9) 1.961 (5), 1.967(2), 1.970(1)A. These changes are consistent with a fluxional behaviour of two 90" misaligned elongated rhombic octahedral Cu06 chromophores separated by less than thermal energy. From the relative thermal populations of the lowest two wells of the potential-energy surface at the three temperatures a Boltzmann distribution, least-squares fit, enables the separation of the two wells, A€, to be determined as 160 f 20 cm-l. From the temperature variations of the single-crystal g values (1 00-298 K) of ( 1) the AEvalue is estimated to be 168 f 40 cm-', which is consistent with the crystallographic estimation of this para meter. The interpretation ' of the temperature variation of the e.s.r. spectrum ' of the copper(r1) doped K2[Zn(OH2)6][S04]2 system in terms of a fluxional behaviour of the Cu06 chromophore between two thermally accessible elongated rhombic octahedral Cu06 stereochemistries misaligned by 90" (Figure l) raises the question of whether the CuO, chromophore stereochemistry of the corresponding concentrated copper(r1) complex also involves a fluxional b e h a ~i o u r . ~-~ The neutron diffraction structure of Rbz[CU(O&)6][S04]2 at 293 and 77 K have already been determined, but showed only a slight change towards a more axially elongated rhombic octahedral stereochemistry at 77 K, consistent with only a small variation of the g values with decreasing temperature. As the single-crystal g values of [ ~~4 ] z [ ~u ( ~~, ) 6 ] [ ~~4 ] ~(1) show a significant variation from 293 to 160 K, the low-temperature (1.t.) crystal structure of (1) has been determined at two temperatures, 203 and 123 K . A preliminary report of the low-temperature structure (ca. 150 K) of (1) has been given elsewhere, involving a microdensitometer estimated set of film data, data which are considered to be less accurate than the present sets of diffractometer data. ExperimentalPreparation.-Crystals of (1) were prepared by slow crystallisation of an equimolar solution of CuS04*SH,0 and (NH4)'S04 containing a few drops of sulphuric acid; the crystals were characterised by microanalysis for H, Cu, N, and S.The crystallographic data for the two low-temperature structures of ( 1 ) and some relevant room temperature (r.t.) data are summarised in Table 1. The data were collected with a Syntex P2, four-circle diffractometer, using the LT-1 lowtemperature attachment at two different temperatures. Maximum 20 was 55', with scan range of -0.8 to +0.95"

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Rapid and efficient syntheses for the preparation of 2'-deoxy-5-vinyluridine and 2'-deoxy-5-vinylcytidine are described starting from nucleoside precursors. Contrary to some previous reports, 2-deoxy-5-vinyluridine has be found to be quite stable under normal laboratory conditions but when tested in animals shows neither toxicity nor anti-leukemic (L1210 cells) or anti-parasitic (Plasmodium berghei) activity. 2'-Deoxy-5-vinylcytidine appears to polymerise readily. It is much less toxic to cell cultures than 2'-deoxy-5'vinyluridine but is almost as active against herpes virus replication (ID50:0.2 microgram/ml) for both type 1 and type 2 herpes virus (selectivity index:225).

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