1975A # -L-3-2-1 A, , +-!- 550 L 5 1 350 300 50- -1- -2--3 I369- -1--2-4-%Optically Active Co-ordination Compounds. Part XXXVII.l ChiropticalProperties of the Ethylened iaminebis( 1 ,I 0- phenant hrol ine)cobalt( 111) IonBy L. S. Dollimore and R. D. Gillard," The Chemical Laboratory, University of Kent at Canterbury, CanterburyThe ion [Co(en) (phen),13+ has been resolved into enantiomers by use of (-)tris(cysteinesulphinato)cobaltate(itl).Contributions in its c.d. spectrum from the ' exciton ' bands of the cis-bis(l.10-phenanthroline) moiety, and fromthe d-d bands of the cobalt ion, provide a correlation between the empirical configurational assignment based ond-d bands and the assignment based on the inherently dissymmetric exciton region.exciton c.d.3 for B, where only two cis-di-imine ligandscouple, is, as expected, considerably smaller than thatfor A, or other tris-complexes.The c.d. in the excitonregion of other tris-bis pairs (e.g.4 [Ru(phen)J2+ and[Ru(phen),(py),I2+) shows the same feature.WE have now completed the series of resolutions for thecomplexes [C0(en),(phen)3-,]~+ (A, x == 0; B, x = 1;C, x = 2; D, x = 3) by resolving €3, the ethylene-diaminebis( 1,lO-phenanthro1ine)cobalt (111) ion. This isthe first complete series in which the end-membersA € 1: I550 500 450 100 350 300--I htnm--2- -3W 1-4C\ -,550 500 4 5 f i O O 350 300A /nmDC.d. spectra of A, [Co(phen),13+ (365-300 nm, Ae/lO: <300 nm, Ae/60): B, [Co(en)(phen)J3+ (<310 nm, Aej30):C, [Co(en),(phen)J 3+ (< 340 nm, A E / ~ ) : D, [Co(en),13+involve fully saturated ligands (i.e.D, [Co(en),I3+) andfully unsaturated ligands (d.e. A, [Co(phen),I3+). In-terestingly, the four less-soluble diastereoisomeric saltsformed with the novel resolving agent ( -)-[Co(cysu)J3-all contain cations having the A configuration.The c.d. spectra are presented in the Figure. The* Pvesent addvess: Departnient of Chemistry, UniversityPart XXXVI, R. D. GilIard, P. R. Mitchell, and C. F. Weick,* L. S. Dollimore and R. D. Gillard, J.C.S. Dalton, 1973, 933.College, Cardiff CF1 IXL.J.C.S. Dalton, 1974, 1635.This finding reinforces an earlier demonstrationof the same point which used the species (+)-[Co-(phen)J3+ (A of this work). Despite the presence ofanomalously large c.d.absorption at ca. 380 nm (ourvalue for AE, -3-9, is larger than that recorded5) theexciton and longest wavelength c.d. bands gave self-consistent assignments of configuration (A).S. F. Mason, Inorg. Chim. A d a Rev., 1968, 2, 89.B. Bosnich, Accounts Chem. Res., 1969, 2, 266.5 S. F. Mason and B. J. Norman, J. Inovg. XzLclsar Chem.Lettevs, 1967, 3, 285370 J.C.S. DaltonMost notably, the exciton region for B shows the dissolved in hot water and reprecipitated as the perchloratetypical pattern (giving an assignment of A configura- [Co(en)(phen)~[C10~3*2H20 by addition of an excess oftion) and a very clear d-d band (positive only) @ving NaC10,solution (Found: C, 39.0; H, 3.1; N, 10.5. Calc.also a A assignment.The two methods a- in this c a e for CZI~H~&~~CON~O,~: c, 38.4; H, 3.45; N, 10.8%).The species [Co(en) (phen),13+ was resolved using the very clearly self-consistent. complex K3( +) -[Co(~-cysu),] according to the procedureEXPERIMENTAL given earlier.2 The structure of the [CO(C~SU)~]~- anionis as yet unknown; however, we have measured the 13Cessentially the method of Palade.' Since difficulties were magnetic resonance spectrum of a saturated neutralencountered, details are given. solution in H,O-D,O of its potassium salt. This showsThe salt [Co(en)(phen),][C10J3*2H,0 was obtained usingCircular dichroism spectra of [Co(en),(phen), -,]3+ ( x = 0-2)A d 483 316A d 480 318 303sh 282As 3.10 3.4 19.7 125.1A d 463 349 335 317 305 281Ef 113 1820 2770 6510 12 550 48600A d 492 378 347 330sh 318sh 302sh 283LE ' 1.29 -3.93 4.60 8-45 12.6 39.6 233AE 0 4-08 - 3.24( + 1 [CO (en) 2 (phen)l 3+(+I w e 4 (phen)aI3+(+ 1 [Co(Phen)313+272270274269- 17.1 a-118.5 b50 900 c- 140 Ua From ref.2. This work. 0 Absorption spectrum. d In nm. 8 The sign for AE is + unless expressly stated. f Isotropicmolar extinction coefficient, 1 mol-l cm-l.The compound [CoCl,(phen),]C1-4~H20 (2.0 g), made bythe method8 of Ablov (Found: C, 47.7; H, 3.6; N, 9.15.Calc. for C,,H2,C1,CoO4.,: C, 47.6; H, 5.3; N, 9.20%)was suspended in hot ethanol (30-40 ml) and an aqueoussolution of ethylenediamine (20% w/v; 1.5 ml) was added,whereupon the solution became yellow-orange. On cool-ing, yellow crystals containing the species [C0(en)~(phen)]3+rapidly formed and were filtered off.Their electronicspectrum in water was identical to that of an authenticsample. The filtrate, when set aside overnight, affordedthree signals of equal intensity at (p.p.m. relative to Me4Si)175.27 (sharp, due to CO,H), 66.67 (broader, probablydue to the CH,), and 57-94 (sharper, due to asymmetriccarbons). In view of this simplicity, it seems probablethat we are dealing with a facial-isomer.Analysis of the diastereoisomer showed it to be a 1 : 1salt with seven water molecules of crystallisation (Found :C, 38-0; H, 4.3; N, 11.0. Calc. for (+)-[Co(en)(phen),]-4.8; N, 11.3%).( +)-[CO(CYSU)~]*~H,O, C3,H,r,,Co2N,01,S3: C, 37.6; H,We thank the Medical Research Council for a studentship a further batch of crystals. The electronic spectrum of a(L. S. D.) and Courtaulds Trust Fund for a grant to solution of these crystals was unlike that of either[Co(en),(phen)]3+ or [Co(phen),13+ and cation-exchange purchase the c.d. spectrometer. chromatography (SP-Sephadex C-25) demonstrated thepresence of only one species. The crystals were re- [3/ 1932 Received, 19th Septembev, 19731R. D. Gillard and P. R. Mitchell, ' Structure and Bonding,' ' D. M. Palade, Russ. J . Inorg. Chem., 1967, 12, 520.8 A. V. Ablov, Russ. J . Inorg. Chem., 1961, 6, 157. 1970, 7, 46, and references therein