~ Pergamon PII: S0277-5387(96)00296-3

Po@hedron Vol. 16, No. 3, pp. 433 439 1997 Copyright :F 1996 Elsevier Science Ltd

Printed in Great Britain. All rights reserved 0277 5387/97 $17.00 +-0,00

Preparation and characterization of iron(+ 2) and ruthenium ( + 2) diiminodiphosphine complexes. X-ray crystal structures of

[(r/5-CsHs)Fe(immpho)] [BF4] • 0.5CH2C12 and { [0/s-CsMes) Ru (CH3CN)] z [immpho] }

{ ZnCl4} "2CH3CN" 2HzO

Wai-Kwok Wong, a* Yang Chen a and Wing-Tak Wong b*

"Department of Chemistry, Hong Kong Baptist University, 224 Waterloo Road, Kowloon, Hong Kong

bDepartment of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong

(Received 23 February 1996; accepted 17 June 1996)

Abstract The interaction ofN, N'-bis[o-(diphenylphosphino)benzylidene]ethylenediamine (immpho) with one and two equivalents of [(r/5-CsMes)Ru(CH3CN)3] + (generated in situ from the reaction of [(r/5-CsMes)RuC12], with excess Zn granular in CH3CN) in CH3CN at room temperature gave [(qs-CsMes)Ru(immpho)]2[ZnCl4] (I) and {[(r/5-CsMes)Ru(CH3CN)]z[immpho]}{ZnCl4} (1I) in 80% and 71% yield, respectively. Upon UV irradiation, immpho reacted with equal molar of [(qsCsHs)Fe(q6-mesitylene)][BF4] in CH~CN at room tem- perature to give [(qs-CsHs)Fe(immpho)][BF4] (III) in 41% yield. Compounds I - I I I have been fully char- acterized by analytical and spectroscopic methods. The structures of I! and III have been established by X-ray diffraction. Copyright ~:) 1996 Elsevier Science Ltd

Keywords: ruthenium(+2) ; i ron(+2) ; ruthenium(+2) dimer; di iminodiphosphine cyclopentadienyl pentamethylcyclopentadienyl.

We have been interested in the chemistry of diim- inodiphosphines as these are polydentate ligands con- taining both phosphorus and nitrogen donor atoms which could behave as soft and hard bases, respec- tively, and act as bridging ligands for the preparation of heterometallic complexes with hard and soft metal centres. We have shown that these ligands exhibit a very rich coordination chemistry and can behave as bridging, hi-, tri- and tetra-dentate ligands depending on the reaction conditions [1-6]. As a tridentate ligand, the diiminodiphosphine ligand exhibits differ- ent modes of coordination toward different metal cen- tres. The diiminodiphosphine ligands coordinate to the Group 6 metals (Cr, Mo) via the two imino groups and one of the phosphino groups with one of the phosphino groups remaining uncoordinated [2,6];

* Authors to whom correspondence should be addressed.

and coordinate to the Group 11 metals (Cu, Ag/ via the two phosphino groups and one of the two imino groups only with one of the imino groups remaining uncoordinated [4,6]. In this paper, we report the coordination mode of N,N'-bis[o-(diphenyl- phosphino)benzylidene]ethylenediamine (immpho), a diiminodiphosphine ligand, toward Group 8 metals, Fe and Ru.

RESULTS AND DISCUSSION

Preparation of [(r/5-C5Me0Ru(immpho)]2[ZnC14] (I)

An acetonitrile solution of [(q%CsMe~)Ru (CH3CN)3 ]+, generated in situ from the reaction of [(qs-CsMes)RuCl~], , with excess Zn granular in CH3CN, was slowly added to a solution of CH2C12 containing one equivalent of immpho at room tern-

433

434 Wai-Kwok Wong et al.

perature; after stirring the solution for an additional 12 h, work up gave dark-red crystals of stoichiometry [(CsMes)Ru(immpho)]2[ZnCl4]'2H20, I '2H20, in good yield (80%) after recrystrallization from a CH3CN/Et20 mixture. The IR spectrum of I exhibits a VC=N stretch at 1626 cm -~ for the imino groups. The 3tp_{ ~H} NMR spectrum of I exhibits two singlets of relative intensity 1 : 1 at 6 43.6 and - 15.6 ppm which correspond to a coordinated and an uncoordinated phosphorus, respectively. This suggests that the immpho ligand behaves as a tridentate ligand with one of its phosphino groups remaining unco- ordinated. This is further supported by the IH NMR spectrum of I which exhibits two broad multiplets of relative intensity of 1 : 1 at 6 9.80 and 8.18 ppm which corresponds to the - - C H - - N - - proton of the unco- ordinated and the coordinated benzylidene, respec- tively. Other than the phenyl protons, the ~H NMR spectrum of I also exhibits a singlet at 6 1.09 ppm for the --CH3 protons of the pentamethylcyclopenta- dienyl ring indicating that the pentamethylcyclo pentadienyl ring is bonded to the ruthenium metal in an q 5 fashion. Based on the above spec- troscopic data, the following structure can be assigned to I.

This is confirmed by an X-ray diffraction study [7] which shows that the diiminodiphosphine ligand acts as a tridentate ligand with one of the two phosphino groups and the two imino groups coordinated to the ruthenium metal and an uncoordinated phosphino group.

However, when the above reaction was carried out in the reverse order, that is by adding a CH2CI2 solu- tion of immpho into an equal molar solution of [(q 5- CsMes)Ru(CH3CN)3] +, generated & situ from the reaction of [(t/5-CsMes)RuCl2], with excess Zn granu- lar in CH3CN, the 31P-{1H} NMR spectrum of the reaction mixture showed that a mixture of I and II (via infra) were obtained. Dark-red crystals of stoichiometry { [(r/5-CsMes)Ru(CH3CN)12[immpho] } {ZnC14}, II, were obtained in good yield (71%) after recrystallization from a CH3CN/Et20 mixture. The 1R spectrum of II exhibits a Vc_ N stretch at 1637 cm- for the imino groups. The 31P-{IH} NMR spectrum of I! exhibits only a singlet at 6 43.2 ppm. This suggests that the two phosphino groups of the immpho ligand were coordinated and equivalent. Other than the phe- nyl protons, the ~H NMR spectrum of II also exhibits a broad multiplet of relative intensity of 2 at fi 8.30 ppm for the - - C H - - N - - protons of the coordinated

Scheme 1.

benzylidenes ; two broad singlets of relative intensity 2 : 2 at ~ 4.55 and 4.40 ppm for the --NCH2CH2N-- protons ; and a singlet of relative intensity of 30 at 6 1.40 ppm for the --CH3 protons of the penta- methylcyclopentadienyl rings, indicating that the two pentamethylcyclopentadienyl rings are equivalent and bonded to the ruthenium metals in an 05 fashion. Based on the above spectroscopic data the following structure can be assigned to U.

The structure of I! was confirmed by an X-ray diffraction study. Crystals of stoichiometry {[0/L C5Mes)Ru(CH3CN)]2[immpho]} {ZnCI4} • 2CH3CN • 2H20 suitable for X-ray diffraction study were grown by slow diffusion of diethyl ether into a concentrated solution of II in CH3CN. A perspective drawing of !I is shown in Fig. 1. Selected bond lengths and bond angles are given in Table 1. The solid state structure is consistent with the spectroscopic data. The dimeric species is centro-symmetric with the pentamethyl- cyclopentadienyl rings bonded to the ruthenium met- als in qS-fashion having the Ru- -C bond lengths ranging from 2.17(2) to 2.21(2) A and the immpho ligand acted as a bidentate ligand having an imino group and a phosphino group coordinated to each of the two [(~5-CsMes)Ru(CH3CN)]+ moieties. Similar bonding behaviour has been reported for the immpho ligand [1]. Within the diiminodiphosphine ligand, the N(1) - -C( l l ) bond length of 1.47(2) /k and the N(I)--C(12) bond length of 1.34(2) A are in agree- ment with the C- -N and C z N bond distances, respectively.

When a CH3CN solution of equal molar of [(qSCsHs)Fe(q6-mesitylene)][BF4] and immpho was irradiated at ambient temperature for 12 h, work up gave dark-red crystal of stoichiometry [(qSCsHs)Fe (immpho)][BF4].CH2Cl2, III" CH2C12, in moderate yield (42%) after recrystallization from a CHzCI2/Et20 mixture. The I R spectrum of lII exhibits a vc_s stretch at 1632 cm 1 for the imino groups. The 3~P-{~H} NMR spectrum of III exhibits two singlets of relative intensity 1 : 1 at 6 67.8 and - 12.6 ppm which correspond to a coordinated and an unco- ordinated phosphorus, respectively. This suggests that the immpho ligand behaves as a tridentate ligand with one of its phosphino groups remaining unco-

Ru CH3CN/I

Ru

Scheme 2.

2+

Fe and Ru diiminodiphosphine complexes 435

Fig. 1. A perspective drawing of the cation of 11.

Table 1. Selected bond lengths (A) and bond angles ( ) for Ii

Ru(I)--P(1) Ru(I)--N(2) Ru(1 )--C(2) Ru( 1 )--C(4) N(I)--C(11) N(2)--C(31)

2.300(5) Ru(I)--N(1) 2.11(1) 2.01 (2) Ru(l )--C(1) 2.21 (2) 2.20(2) Ru(I)--C(3) 2.17(2) 2.19(2) Ru(1 )--('(5) 2.20(2) 1.47(2) N( 1 )--C(12) 1.34(2) 1.04(3)

P(1)--Ru(1)--N(I) 80.8(4) N(1 )--Ru(1)--N (2) 91.7(6) N(1)--C(12)--C(13) 122(1) Ru(1)--N(2)--C(31) 166(2)

P(I )--Ru(I)--N(2) 93.5(5) C(11)--N(I)--C(12) 113(1) N(2)--C(31 )--C(32) 172(2)

ordinated. The resonances of the tH NMR spectrum of I11 are rather broad, indicating that the complex may be weakly paramagnetic. Other than the phenyl protons, the ~H NMR spectrum of III exhibits two broad multiplets of relative intensity 1 : 1 at 6 9.45 and 8.76 ppm for the - - C H - - N - - protons of the uncoordinated and coordinated benzylidene, respec- tively: two broad multiplets of relative intensity 2:2 at 6 4.70 and 3.75 ppm for the --NCH2CH2N-- pro- tons ; and a broad singlet of relative intensity of 5 at 6 2.45 ppm for the protons of the cyclopentadienyl rings, indicating that the cyclopentadienyl ring is bonded to the iron metal in an r/~ fashion. The unusual high field shift of the cyclopentadienyl protons may probably be due to the weak paramagnetism of the complex. The above spectroscopic data suggest that the structure of [If is similar to that of I.

This is confirmed by an X-ray diffraction study. Crystals of stoichiometry [(qs-CsHs)Fe(immpho) ]

[BF4] "0.5CH2C12 suitable for X-ray diffraction study were grown by slo~ diffusion of diethyl ether into a concentrated solution of lII in CH,CL. A perspective drawing oflII is shown in Fig. 2. Selected bond lengths and bond angles are given in Table 2. The solid state structure is consistent with the spectroscopic data. The structure shows that the cyclopentadienyl ring is bonded to the iron metal in rt 5 fashion with the Fe--C bond lengths ranging from 2.05(1) to 2.10(1) A; and the immpho ligand acts as a tridentate ligand with one of the two phosphino groups and the two imino groups coordinated to the iron metal and an unco- ordinated phosphino group. Within the diim- inodiphosphine ligand, the N(1)--C(8) and the N(2)--C(27) bond lengths are 1.27(1) and 1.28(1) A, respectively, and are in agreement with the C- -N bond distance.

The present study shows that the mode of coor- dination of the diiminodiphosphine as a tridentate

436 Wai-Kwok Wong et al.

C(30

C(36)

C(35)~ C(37)

C(38) COl)

c0s)

c(2o) I~

co

C(9)

c04)

C(26

C(25) (

:(10)

C(20

c(l:

C(5)

C(27)

) c(2)

C(4)

P(2)

C(3)

C(44)

C(43)

Fig. 2. A perspective drawing of the cation of IlL

Table 2. Selected bond lengths (A) and bond angles (9) for 1II

Fe(1)--P(1) Fe(1)--N(2) Fe(1)--C(2) Fe(I)--C(4) N(I)--C(8) N(2)--C(6)

2.187(3) Fe(1)--N(1) 1.937(9) 1.979(8) Fe(I)--C(I) 2.05(1) 2.09(1) Fe(I)--C(3) 2.09(1) 2.10(1) Fe(1)--C(5) 2.06(1) 1.27(1) N(1)--C(7) 1.46(1) 1.47(1) N(2)--C(27) 1.28(1)

P(I)--Fe(1)--N(1) 83.5(3) N(1)--Fe(1)--N(2) 82.6(3) N( 1 )--C(8)--C(9) 122.4(9) C(6)--N(2)--C(27) 120.7(8) N(2)--C(6)--C(7) 108.0(8)

P(1)--Fe(1)--N(2) 98.5(2) C(7)--N(1)--C(8) 120.1 (9) N (1)--C(7)--C(6) 106.1 (8) N(2)--C(27)--C(28) 127.2(10)

ligand toward Group 8 metals (Fe and Ru) is similar to that of Group 6 metals; that is having one of the two phosphino groups and the two imino groups coordinated to the metal and the other phosphino group remaining uncoordinated. This may be a gen- eral trend for the diiminodiphosphine, acting as a tridentate ligand, coordinating to Group 8 metals.

E X P E R I M E N T A L

Microanalyses were performed by the Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, China. IR spectra (KBr pellets) were rec- orded on a Nicolet Nagna-IR 550 spectrometer ; data are given in cm-L NMR spectra were recorded on a

JEOL EX270 spectrometer. Chemical shifts of 31p. {~H} NMR spectra were referenced to external 85% H3PO4. Chemical shifts of 1H NMR spectra were ref- erenced to internal deuterated solvents and then recal- culated to TMS = 6 0.00 ppm. Low resolution mass spectra (LRMS) were obtained on a Finnigan MAT SSQ-710 spectrometer in FAB (positive) operation mode and are reported as m/z .

All operations were carried out under nitrogen or in vacuo. All chemicals used were of reagent grade. Solvents were dried by standard procedures. Distilled and deaerated prior to use. Melting points were taken in sealed capillaries and are uncorrected. Pho- tochemical reactions were conducted at room tem- perature with a 450-W Conrad-Hanovia 7825

Fe and Ru diiminodiphosphine complexes

medium-pressure mercury lamp. RuC13"3H20 was purchased from Aldrich and used without further purification. Immpho [6], [(r/SCsMe5)RuCI2], [8] and [(r/SCsH~)Fe(r/6-mesitylene)][BF4] [9] were prepared according to literature methods.

Preparation o['[(r/5-CsMes)Ru(immpho)]z[ZnCI4] (1)

A solution of [(r/5-CsMes)RuCI2], (0.30 g, 1.0 mmol) and granular Zn (1.2 g, 18.5 mmol) in methanol (10 cm 3) was refluxed for 10 rain. Then CH3CN (10 cm 3) was added to the methanol solution and the resultant solution was maintained refluxing for another 5 h. The colour of the reaction mixture changed to orange. Upon cooling to room temperature, the solution was filtered. The filtrate was then added dropwise to a stirring solution of immpho (0.61 g, 1.0 mmol) in CH:CI: (10 cm~). The reaction mixture was allowed to stir at room temperature for another 12 h to give a dark-red solution. The solvents were removed in vacuo to give a dark-red residue. The residue was redissolved in a minimum amount of CH3CN and chro- matographed on a silica gel column (2 x 15 cm) using CH~CN as an eluant. The dark-red band obtained was concentrated to ca 5 cm 3 and then diethyl ether was added until the solution just turned cloudy. The CH,CN/die thyl ether mixture was then cooled to - 2 0 C to give dark-red crystals, which were filtered and dried in vacuo. Yield: 0.83 g, 79%; m.p. 220 223 C. Found: C, 62.2; H, 5.1: N, 2.8. Calc. for (C,~oH~N4P4C14ZnRu2)'2H20: C, 62.4; H, 5.3; N, 2.9%. IR (cm t in KBr) : 3440 br, s, 3052 m, 2902 m, 1626 m, 1584w, 1476 m, 1432 s, 1384w, 1294w, 1268 w, 1218 w, 1090 m, 1070 w, 1022 m, 920 w, 746 s, 694 vs, 508 s, 490 m. ~IP-[~H~ N M R (CDCI3): unco- ordinated PPh2 group, 6 - 15.6(s) ppm; coordinated PPh2 group, 6 43.6(s) ppm. ~H N M R (CDC13): - - C H - - N - - proton of uncoordinated benzylidene, 6 9.80 (1H,m) ppm; - - C H - - N - - proton of coor- dinated benzylidene, 6 8.18 ( 1 H, m) ppm ; phenyl pro- tons, 6 6.80-7.80 (28H, br, m) ppm ; - - N C H 2 C H 2 N - - protons, 6 3.90~4.20 (4H, br, m) ppm; H20 protons, 6 2.01 (2H, s) ppm ; CH3 protons, 6 1.09 (15H, s) ppm.

Preparation q[ { [(q'-C~Mes)Ru(CH3CN)]2[immpho]} ~ ZnC14 ~ (II)

A solution of [(q5-CsMes)RuC12] . (0.30 g, 1.0 mmol) and granular Zn (1.2 g, 18.5 mmol) in methanol (10 cm 3) was refluxed for 10 min. Then CH3CN (10 cm 3) was added to the methanol solution and the resultant solution was maintained refluxing for another 5 h. The colour of the reaction mixture changed to orange. Upon cooling to room temperature, the solution was filtered and stirred. Then a solution of immpho (0.30 g, 0.5 mmol) in CH2C12 (10 cm 3) was then added dropwise to the orange filtrate. The reaction mixture was allowed to stir at room temperature for another 12 h to give a dark-red solution. The solvents were

437

removed in vacuo to give a dark-red residue. The resi- due was redissolved in a minimum amount of CH~CN and chromatographed on a silica gel column (2 x 15 cm) using CH3CN as an eluant to give a dark-red band. The solvent of the dark-red band was removed in vacuo to give a dark-red residue which was redis- solved in a minimum amount of CH2C12. Then diethyl ether was added to the CH2C12 solution until it just turned cloudy. The CH2Clz/diethyl ether mixture was then cooled to - 20 C to give dark-red crystals, which were filtered and dried in vacuo. Yield : 0.47 g, 71% : m.p. 231-232 C. Found : C, 56.0 ; H, 5.2 ; N, 4.2. Calc. for (C~,4Hy0NnPzCI4ZnRu2) "0.5H20 : C, 55.9 ; H, 5.2 : N, 4.1%. IR (cm -~, in KBr): 3433 br, s, 3051 w, 2920 s, 2853 m, 1701 w, 1637 m, 1560 w, 1477 m, 1435 s, 1374 w, 1298 w, 1261 row, 1188 w~ 1089 s, 1068 m. 1026 s, 912 w, 800 m, 746 s, 730 m, 699 vs, 528 vs, 486 m. 3~p_t~H~ N M R (CDCId : coordinated PPh~_ group,

43.2(s) ppm. ~H N M R (CDC10: - - C H - : N - - protons, 6 8.34 (2H, br, m) ppm; phenyl protons, 6 6.68 7.80 (28H, br, m) ppm; - - N C H , C H ~ N - - protons, 6 4.55 (2H, br, s) and 4.40 (2H, br, s) ppm : - - C H 3 protons o fCH3CN, 6 1.52- 1.63 (6H, m) ppm : - -CH~ protons of CsMe~, 6 1.40 (30H, br, s) ppm.

Preparation 0[ [015-C~H~) Fe(immpho)] [B F4] (II1)

A solution of [(qs-CsHs)Fe(r/'-mesitylene)][BF~] (0.33 g, 1.0 mmol) and immpho (0.60 g, 1.0 retool) in CH3CN (30 cm ~) was irradiated at room temperature for 12 h. The colour of the solution changed from yellow to red-brown. The solvent of the resultant solu- tion was removed in vacuo to give dark-red residue. The residue was redissolved in a minimum amount ol" CHaCN and chromatographed on a silica gel volume (2 x 15 cm) using CH~CN as an eluant to give a dark- red band. The solvent of the dark-red band was removed in vacuo to give a dark-red residue which was redissolved in a minimum amount of CH,CL. Then diethyl ether was added to the CH2CI: solution until it just turned cloudy. The CH2Cl2/diethyl ether mix- ture was then cooled to - 2 0 C to give dark-red crys- tals, which were filtered and dried in racuo. Yield: 0.34 g, 4 2 % ; m.p. 182-184'C. Found: C, 61.9: H, 4.5 ; N, 3.0. Calc. for (C45H3~N_,P_,BF~Fe) • CHzCI2 : C, 61.6, H, 4.6: N, 3.1%. IR (cm ~,in KBr): 3053 w, 2956 w, 2923 m, 2854 w, 1623 m, 1582 w, 1480 w. 1435 s, 1387 w, 1262 w, 1268 w, 1084 vs, 1055 vs, 1037 vs, 840 w, 815 w, 751 s, 698 s, 532 m, 519 s, 466 m. .~lp ~ N M R (CD,CI,) : uncoordinated PPh, group, 6 -12 .6(s ) ppm; coordinated PPh_, group, 6 67.8(s) ppm. IH N M R (CD2C12): - - C H - - N - - proton of uncoordinated benzylidene, 6 9.45 (1H, br, s) ppm: - - C H - ~ N - - proton of coordinated benzylidene, 6 8.76 (1H, br, s) ppm; phenyl protons, 6 6.80 7.80 126H, br, m) and 6.00 (2H, br, s) ppm; - - N C H ~ C H 2 N - - protons, 6 4 .60~.83 (2H, br, m) and 3.52- 4.00 (2H, br, m) ppm ; C5H5 protons. 6 2.45 (5H, br, sl ppm. LRMS (FAB: +ve ) m/c: 725.

438 Wai -Kwok W o n g et al.

X - ray di f f ract ion s tudies

The general procedures for the X-ray diffraction studies are described as below. Crystals were m oun t ed on glass fibres with epoxy resin. Intensi ty da ta were collected on a Rigaku A F C 7 R diffractometer with graphi te m o n o c h r o m a t e d Mo-K~ radia t ion (2 = 0.71073 A) using eJ-20 scans (20max ~< 45 °) at room temperature . The da ta were corrected for Lorentz, po lar iza t ion effects and absorp t ion cor- rect ion using ~k-scan me thod [10]. Crystal data, da ta collection parameters , and results of the analysis are given in Table 3. The structures were solved by Direct Me thods (SIR88) [11] and refined by full matr ix least- squares technique. For c o m p o u n d II, an acetonitr i le and a water molecule are found in the asymmetr ic unit . They were refined to give relatively h igh thermal

displacement parameters . Fo r c o m p o u n d III, a par- tially occupied solvate of d ich loromethane is revealed in the asymmetr ic uni t and their a tomic posi t ional and thermal parameters were refined with occupancy 0.5. Wi th this model, the ref inement converged to give the best R and R w factors and more reasonable thermal parameters for this solvate. The hydrogen a toms were generated in their idealized posi t ions ( C - - H bond fixed at 0.95 A) and included in s t ructure factor cal- culat ions but no t refined. All calculat ions were per- formed on a Si l icon-Graphics compute r using the p rog ram package Texsan [12] f rom MSC.

(a) C o m p o u n d U. Crystals of II suitable for X- ray diffraction study were grown from CH3CN/ diethyl ether as a solvate of s toichiometry I I ' 2 C H 3 C N ' 2 H z O . A red plate of dimensions of 0.24 x 0.28 × 0.34 m m 3 was moun ted on a glass fibre

Table 3. Data collection and processing parameters for II and III

II III

Empirical formula C 6 8 H s 0 0 2 N 6 P z C 1 4 Z n R u 2 C45.sH40N2P2BF4FeCI Colour and habit Red plate Red plate Crystal size (ram) 0.24 × 0.28 × 0.34 0.30 × 0.38 × 0.40 Crystal system Triclinic Triclinic Space group PT (No. 2) PT (No. 2) Unit cell dimensions a = 13.391(1) (A) a = 13.782(6) (A)

b = 15.011(2) (A) b = 15.935(3) (A) c = 12.225(2) (A) c = 11.232(3) (A)

= 91.08(1) (°) ~ = 110.02(2) C) 3 = 103.93(1) (°) /~ = 100.47(3) (°) ), = 113.28(1) (") y = 102.66(3) (') V = 2172.8(5) (A 3) V = 2170(1) (A 3) Z = l Z = 2

Formula weight 1484.70 854.88 Density (calc,) 1.135 (g cm 3) 1.308 (gcm 3) Absorption coefficient 8.14 (cm ~) 5.33 (cm ~) F(000) 762 882 Diffractometer Rigaku AFC7R Rigaku AFC7R Radiation Mo-K~ (2 = 0.71073 A) Mo-K~ (Z = 0.71073 ,~,) Temperature (K) 298 301 Scan type 09-20 o~-20 Scan speed 16.0 (° min (in co)) (up to 4 scans) 16.0 ( rain (in o9)) (up to 6 scans) 20ma x 45.0' 45.0 Scan range (o~) (0.94 + 0.34 tan 0)-' (0.79 + 0.34 tan 0)' Reflections collected 5964 7236 Independent reflections 5673 (Rmt = 3.3%) 6821 (R,,, = 3.0%) Observed reflections 3164 [I > 3.0or(/)] 4617 [I > 3.0or(/)] Absorption correction ~b-scan 0-scan Transmission factors 0.8790-1.0000 0.9334-1.0000 Structure solution Direct Methods (SIR88) Direct Methods (SIR88) Refinement method Full-matrix least-squares Full-matrix least-squares Function minimized l~w(I F,,I- IF, l) z ~,w(lFol- IF,.I) 2 Weighting scheme w = [a~ (Fo) + (p/2)2F2o] -~ w = [a~ (Fo) + (p/2)2F2o] p-factor 0.005 0.006 R indices (obs. data) R = 0.089; wR = 0.092 R = 0.081 ; wR = 0.091 Goodness-of-fit 2.08 4.08 Largest A/a 0.01 0.02 Number of parameters 270 509 Residual extrema (e/~ 3) 1.04 to - 1.09 1.22 to -0.88

Fe and Ru diiminodiphosphine complexes

with epoxy resin. A total of 5673 unique reflections (20~<45) were measured; 3164 of these had 1 >/3a(/) and were considered to be observed.

(b) Compound III. Crystals of III suitable for X- ray diffraction study were grown from CH2C12/diethyl ether as a solvate of stoichiometry III" 0.5CH2C12. A red plate of dimensions of 0.30 x 0.38 × 0.40 mm 3 was mounted on a glass fibre with epoxy resin. A total of 6821 unique reflections (20 ~< 45') were measured: 4617 of these had I ~> 3a(/) and were considered to be observed.

Acknowledqements W.-K.W. thanks the Hong Kong Baptist University and the Hong Kong Research Grants Council tbr financial support. W.-T.W. thanks the Hong Kong Research Grants Council and the University of Kong Hong fl~r financial support.

REFERENCES

I. W, K. Wong, J.-X. Gao, Z.-Y. Zhou and T. C. W. Mak, Polyhedron 1992, 11, 2965.

439

2. W. K. Wong, J.-X. Gao and W. T. Wong, Poh'- hedron 1993, 12, 1647.

3. W. K. Wong, J.-X. Gao and Z.-Y. Zhou and T. C. W. Mak, Polyhedron 1993, 12, 1415.

4. W. K. Wong, J.-X. Gao, W. T. Wong, W, C. Cheng and C. M. Che, J. Or qanomet. Chem. 1994, 471,277.

5. J.-X. Gao, H.-L. Wan, W. K. Wong, M. C. Tse and W. T. Wong, Polyhedron 1996, 15, 1241.

6. J. C. Jeffrey, T. B, Rauchfuss and P. A. Tucker, Inor~t. Chem. 1980, 19, 3306.

7. W. K. Wong, Y. Chen and W. T. Wong. Poh'- hedron 1996, 15, 1575.

8. P. J. Fagan, M. D. Ward, J. V. Caspar, J. C. Calabrese and P. J. Krusic, J. Amer. Chem. Soc. 1988. 110, 2981.

9. A. M. McNair, J. L. Schrenk and K. R. Mann, Inor, q. Chem. 1984, 23, 2633.

10. A. C. T. North. D. C. Phillips and F. S. Mathews, Acta Co,st. Sect A. 1968, 24, 351.

11. M. C. Burla, R. Camalli, G. Cascarano, C. Gia- covazzo, G. Polidori, R. Spagna and D. Viterbo. J. Appl. Co'st. 1989, 22, 389.

12. Texsan: Crystal Structure AnaO'sis Package. Molecular Siructure Corporation (I 985, 1992).