Synthesis, co-ordination chemistry and crystallographic studies of some bis(aminophosphines)

Article abstract of DOI:10.1039/a608141j

l,2-Bis(diphenylphosphinoamino)benzene 1 and 3,4-bis(diphenylphosphinoamiho)toluene 2 have been prepared; 1 is oxidised by sulfur or selenium to C6H4(NHPPh2S)₂-l,2 3 and C6H4(NHPPh2Se)₂-l,2 4 and by sulfur and selenium to C6H4(NHPPh2S)(NHPPh2Se)-l,2 5. The napthalene compounds C)0H6(NHPPh2S)₂-l,8 6, CIOH6(NHPPh2Se)₂-l,8 7, C10H6(NHPPh2S)(NHPPh2Se)-l,8 8 and the ethane compound C2H4(NHPPh2S)₂-l,2 9 have also been prepared. The co-ordination of 2 to Mo°, Pd, Pt and Au1, i.e. in cw-[Mo(CO)4L], cw-[MC!2L] (M = Pd or Pt) and [(AuCl)₂L] [L = MeC6H3(NHPPh2)₂-3,4] is also described. The crystals structures of representative examples have been determined.

Full text of DOI:10.1039/a608141j

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Synthesis, co-ordination chemistry and crystallographic studies of
some bis(aminophosphines)
Tuan Q. Ly, Alexandra M. Z. Slawin and J. Derek Woollins*,†
Department of Chemistry, Loughborough University, Loughborough LE11 3TU, UK
1,2-Bis(diphenylphosphinoamino)benzene 1 and 3,4-bis(diphenylphosphinoamino)toluene 2 have been prepared;
1 is oxidised by sulfur or selenium to C6H4(NHPPh2S)2-1,2 3 and C6H4(NHPPh2Se)2-1,2 4 and by sulfur and
selenium to C6H4(NHPPh2S)(NHPPh2Se)-1,2 5. The napthalene compounds C10H6(NHPPh2S)2-1,8 6,
C10H6(NHPPh2Se)2-1,8 7, C10H6(NHPPh2S)(NHPPh2Se)-1,8 8 and the ethane compound C2H4(NHPPh2S)2-1,2
9 have also been prepared. The co-ordination of 2 to Mo0, PdII, PtII and AuI, i.e. in cis-[Mo(CO)4L], cis-[MCl2L]
(M = Pd or Pt) and [(AuCl)2L] [L = MeC6H3(NHPPh2)2-3,4] is also described. The crystals structures of
representative examples have been determined.
1,2-Bis[(diphenylphosphino)methyl]benzene has been known
for some time1 and shown readily to form complexes contain-
ing seven-membered chelate rings.2,3 The related system 1,4-
bis(diphenylphosphino)butane also complexes with a wide
range of transition metals.4 There is substantial interest in
the catalytic potential of chelating diphosphine–palladium/
platinum() complexes as they are known to be responsible for
many types of selective chemical reactions.5,6 Molybdenum–
bis(diphosphine) compounds7,8 also have catalytic potential.9
Interestingly, there have been relatively few reports on non-
carbon spacers between the carbon backbone and the adjacent
phosphines. Similarly whilst the chemistry of acetylacetones is
extensive, work on the non-carbon relatives R2P(E)NH(E)PR2
has been on a more modest scale until recently.10,11 Here, we
report on the synthesis and complexation properties of some
bidentate phosphines where amino groups are incorporated as
spacers between the phosphorus atoms and the aromatic back-
bone. Examples of their co-ordination chemistry with molyb-
denum, palladium, platinum and gold are described.
cm3, 47.8 mmol) and 4-(dimethylamino)pyridine (100 mg, 0.8
mmol). A tetrahydrofuran (50 cm3) solution of chlorodiphenyl-
phosphine (8.6 cm3, 47.8 mmol) was added dropwise (white
precipitate of NEt3HCl formed immediately). Stirring was con-
tinued for 3 h. The solution was filtered through a sintered
Schlenk tube and the residue washed with tetrahydrofuran
(2 × 30 cm3). The filtrate was evaporated to dryness and then
the light brown oil was washed with diethyl ether (3 × 50 cm3)
to give a light brown powder in a crude yield of 5.09 g (45%),
1
m.p. 82–85 ЊC. NMR (CDCl3): H, δ 7.37 (m, aromatic), 6.85
(m, aromatic) and 4.35 (2 H, d, NH); 13C, δ 131.2, 130.9, 129,
128.5, 128.4, 121.9, 119.8 and 119.5; 31P, δ 32.5. IR (KBr disc,
cmϪ1): 3328w, 3066vw, 3044w, 3001vw, 1648vw, 1593s, 1578m,
1492s, 1455m, 1433s, 1357w, 1338vw, 1291m, 1265w, 1245m,
1182w, 1154w, 1091s, 1068m, 1037m, 1025m, 998m, 939m,
904vs, 868m, 847m, 752vs, 738vs, 696vs, 619w, 572w, 515vs,
470vs, 438s, 422m, 361m, 348m and 302s. FAB mass spectrum:
m/z 477, [M ϩ H]ϩ (Found: C, 74.9; H, 5.6; N, 4.3. C30H26N2P2
requires C, 75.6; H, 5.5; N, 5.9%).
MeC6H3(NHPPh2)2-3,4 2. To a tetrahydrofuran (50 cm3)
solution of 3,4-diaminotoluene (3.8 g, 31.1 mmol) was added
triethylamine (9 cm3, 64.6 mmol) and 4-(dimethylamino)-
pyridine (200 mg, 1.6 mmol). A solution of chlorodiphenyl-
phosphine (11 cm3, 60.3 mmol) in tetrahydrofuran (100 cm3)
was added dropwise. Stirring was continued for 2 h. The solu-
tion was filtered through a sintered Schlenk tube and the resi-
due washed with tetrahydrofuran (2 × 40 cm3). The filtrate was
evaporated to dryness in vacuo. The product was washed with
ether (2 × 50 cm3) and then dried in vacuo to give a yield of 14.1
g (93%), m.p. 71–73 ЊC. NMR (CDCl3): 31P, δ 33.3 and 30.4; 1H,
δ 7.21 (m, aromatic), 6.90 (m, aromatic), 6.84 (d, aromatic),
6.50 (d, aromatic), 4.38 (d, J = 8 Hz, NH), 3.89 (1 H, d, NH)
and 2.12 (3 H, s, CH3); 13C, δ 128 (m, aromatic) and 19.8 (1 C, d,
CH3). IR (KBr disc, cmϪ1): 3329vw, 3320vw, 3067vw, 2954vw,
1656vw, 1647vw, 1608m, 1571w, 1504vs, 1479s, 1433vs, 1365m,
1325w, 1297s, 1262m, 1174m, 1114m, 1093s, 1069w, 1026w,
999w, 960m, 887s, 849m, 819m, 749s, 738vs, 696vs and 508s
(Found: C, 73.9; H, 5.6; N, 5.5. C31H28N2P2 requires C, 75.9; H,
5.7; N, 5.7%).
Experimental
General
Diethyl ether, light petroleum (b.p. 60–80 ЊC) and tetrahydro-
furan were purified by reflux over sodium and distillation under
nitrogen. Dichloromethane was heated to reflux over powdered
calcium hydride and distilled under nitrogen. Chemicals from
Aldrich and Lancaster were 3,4-diaminotoluene, 1,2-
diaminobenzene, 1,8-diaminonaphthalene, triethylamine and
chlorodiphenylphosphine which were purified by sublimation
or distillation before use; 4-(dimethylamino)pyridine was used
as received. The compounds [Mo(CO)4(pip)2] (pip =
piperidine),12 [MCl2(cod)] (M = Pd or Pt, cod = cycloocta-
1,5-diene)13 and [AuCl(tht)] (tht = tetrahydrothiophene)14 were
prepared using literature procedures.
Infrared spectra were recorded from KBr discs on a Perkin-
Elmer system 2000 spectrometer, 31P NMR spectra on a JEOL
FX90Q operating at 36.21 MHz, 1H, 13C and 31P NMR spectra
on Bruker instruments operating at 250, 62.9 and 101.3 MHz
respectively, and fast atom bombardment (FAB) mass spectra
by the Swansea mass spectrometer service.
C6H4(NHPPh2S)2-1,2 3. Compound 1 (3.38 g, 7.1 mmol) was
dissolved in tetrahydrofuran (50 cm3) and sublimed sulfur (462
mg, 14.4 mmol) was added. The yellow sulfur powder gradually
disappeared and the flask felt warm as all the sulfur dissolved.
The solvent was removed from the reaction mixture in vacuo
and the white material washed with carbon disulfide (2 × 30
Preparations
C6H4(NHPPh2)2-1,2 1. To 1,2-diaminobenzene (2.58 g, 23.9
mmol) in tetrahydrofuran (50 cm3) was added triethylamine (6.4
† E-Mail: j.d.woollins@lboro.ac.uk
J. Chem. Soc., Dalton Trans., 1997, Pages 1611–1616
1611

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cm3) and diethyl ether (2 × 30 cm3), yield 3.03 g (79%), m.p.
164–167 ЊC. 31P NMR (CDCl3): δ 56.7. IR (KBr disc, cmϪ1):
3312w, 3054w, 1640m, 1600m, 1561w, 1499s, 1436vs, 1382m,
1295ms, 1258w, 1206vw, 1104vs, 1049w, 1027vw, 998vw, 943w,
930vs, 896w, 806w, 750vs, 714vs, 692vs, 661w, 639vs, 631s,
614m, 565w, 509s, 496s, 451w, 439w and 407w. FAB mass spec-
trum: m/z 563, [M ϩ Na]ϩ; 541, [M ϩ H]ϩ; 540, Mϩ; 324,
[M ϩ H Ϫ Ph2PS]ϩ and 291, [M ϩ H Ϫ Ph2PS2]ϩ (Found: C,
65.3; H, 4.5; N, 5.2. C30H26N2P2S2 requires C, 66.6; H, 4.9; N,
5.2%).
640w, 619w, 569s, 551vs, 515s, 497m, 481m, 460m and 382m.
FAB mass spectrum: m/z 687, [M ϩ H]ϩ and 686, Mϩ (Found:
C, 58.8; H, 3.4; N, 4.1. C34H28N2P2Se2 requires C, 59.5; H, 4.1;
N, 4.1%).
C10H6(NHPPh2S)(NHPPh2Se)-1,8 8. This compound was
prepared in the same way as for 5 where 1,8-diamino-
naphthalene (755 mg, 4.8 mmol), triethylamine (1.4 cm3, 10
mmol), 4-(dimethylamino)pyridine (30 mg, 0.2 mmol), chlo-
rodiphenylphosphine (1.6 cm3, 9.3 mmol), sulfur (125 mg, 3.9
mmol) and grey selenium (308 mg, 3.9 mol) were used to give a
yield of 1.4 g (45%), m.p. 250–252 ЊC. 31P NMR (CDCl3): δ 56.1
C6H4(NHPPh2Se)2-1,2 4. Compound 1 (4.52 g, 9.5 mmol) in
toluene (150 cm3) and selenium (1.5 g, 19 mmol) were stirred for
1 h. A white precipitate formed within 10 min of addition of
grey selenium. Tetrahydrofuran (100 cm3) was added to dissolve
the product and the solution was then passed through Celite.
The solvent was removed (Rotavap.) to yield 5.14 g (85%), m.p.
112–115 ЊC. 31P NMR (CDCl3): δ 53.9 [1J(PSe) 764 Hz]. IR
(KBr disc, cmϪ1): 3308w, 3052vw, 1600w, 1561w, 1498s, 1478m,
1435vs, 1381m, 1311w, 1293m, 1255m, 1184w, 1100vs, 1049w,
1026vw, 998vw, 944w, 923s, 891w, 853vw, 805w, 750vs, 714s,
690vs, 618vw, 606vw, 559s, 545s, 522s, 508s, 489s and 387w.
FAB mass spectrum: m/z 637, [M ϩ H]ϩ and 636, Mϩ (Found:
C, 56.2; H, 3.9; N, 4.4. C30H26N2P2Se2 requires C, 56.6; H, 4.1;
N, 4.4%).
[5J(PP) 22] and 53.0 [5J(PP) 22, 1J(P᎐Se) 792 Hz]. IR (KBr disc,
᎐
cmϪ1): 3143vw, 3054vw, 1642vw, 1613w, 1599w, 1576m, 1478w,
1436s, 1393s, 1309m, 1266s, 1162w, 1123vw, 1097s, 1070w,
1034s, 998m, 979vw, 921m, 892s, 835s, 764vs, 744vs, 728vs,
713vs, 690vs, 645m, 630s, 612s, 555s, 538s, 517s, 501s, 482m,
470m and 388s. FAB mass spectrum: m/z 639, [M ϩ H]ϩ
(Found: C, 63.9; H, 3.8; N, 4.0. C34H28N2P2SSe requires C, 63.9;
H, 4.4; N, 4.4%).
C2H4(NHPPh2S)2-1,2 9. This was prepared in the same way as
for compound 3. 1,2-Diaminoethane (0.9 cm3, 13.5 mmol), tri-
ethylamine (4.2 cm3, 30.1 mmol), 4-(dimethylamino)pyridine
(100 mg, 0.8 mmol), chlorodiphenylphosphine (5 cm3, 27.8
mmol) and sulfur (0.9 g, 28.1 mmol) were used to give a yield of
4.5 g (65%), m.p. 118–121 ЊC. 31P NMR (CDCl3): δ 60.4. IR
(KBr disc, cmϪ1): 3368m, 3266w (br), 3052w, 2977w, 2937w,
2879w, 2739w, 2677w, 2603m, 2495m, 1476s, 1437vs, 1398s,
1384m, 1309w, 1201m, 1173m, 1105vs, 1083vs, 1037s, 997m,
863m, 853m, 807w, 754s, 742s, 716vs, 698vs, 692vs, 633s, 627s,
613s, 531s, 497s, 462w, 404w, 247m and 240w. FAB mass spec-
trum: m/z: 515, [M ϩ Na]ϩ; and 493, [M ϩ H]ϩ (Found: C, 62.6;
H, 4.9; N, 5.6. C26H26N2P2S2 requires C, 63.4; H, 5.3; N, 5.7%).
C6H4(NHPPh2S)(NHPPh2Se)-1,2 5. The intermediate was
prepared in the same way as compound 1, from 1,2-
Diaminobenzene (1.36 g, 12.6 mmol), triethylamine (3.6 cm3, 26
mmol), 4-(dimethylamino)pyridine (55 mg, 0.4 mmol) and
chlorodiphenylphosphine (4.5 cm3, 25.1 mmol). Sulfur (403 mg,
12.6 mmol) was added and stirred for 1 h followed by grey
selenium (993 mg, 12.6 mmol) and allowed to react overnight.
The solution was passed through Celite, then the solvent was
removed in vacuo and the product washed with ether (2 × 40
cm3) to give a yield of 6.98 g (94%), m.p. 210–212 ЊC. 31P NMR
(CDCl3): δ 56.8 [5J(PP) 13] and 53.4 [5J(PP) 13, 1J(PSe) 764 Hz].
IR (KBr disc, cmϪ1): 3310w, 3055vw, 1647w, 1596m, 1561w,
1499vs, 1479m, 1458w, 1436vs, 1382s, 1294vs, 1256m, 1184s,
1158m, 1101vs, 1070w, 1049w, 1026w, 998w, 943m, 929vs,
894m, 854vw, 809m, 790m, 750vs, 714vs, 691vs, 638s, 614m,
607m, 556s, 524s, 507s, 494s, 439w and 401w. FAB mass
spectrum: m/z 611, [M ϩ Na]ϩ; 589, [M ϩ H]ϩ and 588, Mϩ
(Found: C, 61.0; H, 4.2; N, 4.7. C30H26N2P2SSe requires C, 61.2;
H, 4.5; N, 4.8%).
cis-[Mo(CO)4{MeC6H3(PNHPPh2)2-3,4}]. To a partially dis-
solved solution of [Mo(CO)4(pip)2] (99 mg, 262 µmol) in dichlo-
romethane (15 cm3) was added 3,4-bis(diphenylphosphino-
amino)toluene 2 (147 mg, 300 µmol). The cloudiness in the solu-
tion disappeared after 5 min of stirring. Stirring was continued
for 2 h and then the solvent was removed in vacuo. The light
yellow product was washed with light petroleum (2 × 20 cm3)
and dried in vacuo to give a yield of 180 mg (98%), m.p. 208–
211 ЊC. 31P NMR (CDCl3): δ 84.9 and 84.6 [2J(PP) 35 Hz]. IR
(KBr disc, cmϪ1): 3333vw, 3054vw, 2924vw, 2853vw, 2026vs,
1947vs, 1911vs (br), 1608vw, 1585vw, 1509m, 1479m, 1433s,
1365w, 1295m, 1260w, 1217vw, 1181vw, 1159vw, 1125w, 1090s,
1071vw, 1027vw, 999vw, 963vw, 907m, 858vw, 815vw, 742s,
697vs, 647vw and 607s. FAB mass spectrum: m/z 700, Mϩ
(Found: C, 59.6; H, 3.6; N, 4.0. C35H28MoN2O4P2 requires C,
60.0; H, 4.0; N, 4.0%).
C10H6(NHPPh2S)2-1,8 6. This compound was prepared in the
same way as for 3. 1,8-Diaminonaphthalene (1 g, 6.5 mmol),
triethylamine (1.9 cm3, 14.3 mmol), 4-(dimethylamino)pyridine
(80 mg, 0.6 mmol), chlorodiphenylphosphine (2.3 cm3, 12.8
mmol), and sulfur (500 mg, 16 mmol) were used to give a yield
of 2.37 g (62%), m.p. 238–241 ЊC. 31P NMR (CDCl3): δ 57.9.
IR (KBr disc, cmϪ1): 3147w, 3055vw, 1639vw, 1600w, 1577m,
1561vw, 1510vw, 1437vs, 1396s, 1310m, 1267vs, 1177vw,
1161vw, 1108vs, 1107vs, 1069vw, 1035vs, 998w, 922w, 893s,
836s, 766vs, 745vs, 730vs, 718vs, 690vs, 648s, 629vs, 613vs, 565s,
520vs, 502vs, 485s, 436m, 420s and 390s. FAB mass spectrum:
m/z 591, [M ϩ H]ϩ (Found: C, 68.5; H, 4.5; N, 4.6.
C34H28N2P2S2 requires C, 69.1; H, 4.8; N, 4.7%).
cis-[PdCl2{MeC6H3(PPh2)2-3,4}]. To solution of [PdCl2(cod)]
(33 mg, 88 µmol) in dichloromethane (5 cm3) was added 3,4-
bis(diphenylphosphinoamino)toluene 2 (44 mg, 90 µmol). The
solvent was removed and the product washed with light petrol-
eum (2 × 10 cm3) to give a crude yield of 56 mg (94%),
decomp. 200–202 ЊC. 31P NMR (CDCl3): δ 62.4 and 60.1
[2J(PP) 31 Hz]. IR (KBr disc, cmϪ1): 3169w, 3052w, 2920vw,
2854vw, 1595vw, 1512m, 1481m, 1459w, 1435vs, 1389w, 1312m,
1262vw, 1222vw, 1183vw, 1160vw, 1128vw, 1101vs, 1027w,
998w, 817w, 744s, 711m, 691vs, 510vs, 469m and 295m. FAB
mass spectrum: 691, [M ϩ Na]ϩ; 668, Mϩ; 633, [M Ϫ Cl]ϩ;
596, [M Ϫ 2Cl]ϩ (Found: C, 55.1; H, 3.6; N, 4.0.
C31H28Cl2N2P2Pd requires C, 55.8; H, 4.2; N, 4.2%).
C10H6(NHPPh2Se)2-1,8 7. This compound was prepared in
the same way as for 4. 1,8-Diaminonaphthalene (1.2 g, 7.6
mmol), triethylamine (2.2 cm3, 15.8 mmol), 4-
(dimethylamino)pyridine (50 mg, 0.4 mmol), chlorodiphenyl-
phosphine (2.6 cm3, 14.5 mmol), and grey selenium (1.2 g, 15
mmol) were used to obtain a yield of 1.2 g (22%), m.p. 260–
264 ЊC. 31P NMR (CDCl3): δ 53.3 [1J(PSe) 792 Hz]. IR (KBr
disc, cmϪ1): 3127vw, 3049vw, 1598vw, 1575vw, 1475vw, 1436s,
1390s, 1309w, 1265s, 1097s, 1069w, 1034s, 1027m, 998w, 978vw,
921w, 892m, 867vw, 835m, 763vs, 742vs, 725vs, 712m, 689vs,
cis-[PtCl2{MeC6H3(NHPPh2)2-3,4}]. This was prepared in
the same way as the palladium complex using [PtCl2(cod)] (100
mg, 267 µmol) and 3,4-bis(diphenylphosphinoamino)toluene 2
(133 mg, 271 µmol) to give a yield of 202 mg (100%), m.p.
1612
J. Chem. Soc., Dalton Trans., 1997, Pages 1611–1616

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Table 1 Selected IR and NMR spectroscopic data for compounds 1–9
Compound
31P NMR (δ, J/H2)
ν(NH)
ν(PN)
ν(P᎐E)
᎐
1 C6H4(NHPPh2)2
2 MeC6H3(NHPPh2)2
3 C6H4(NHPPh2S)2
4 C6H4(NHPPh2Se)2
5 C6H4(NHPPh2S)(NHPPh2Se)
6 C10H6(NHPPh2S)2
7 C10H6(NHPPh2Se)2
8 C10H6(NHPPh2S)(NHPPh2Se)
9 C2H4(NHPPh2S)2
32.5
3328m
3329w, 3320w
3312w
3308w
3310w
904vs, 738vs
887s, 738vs
930vs, 714vs
923vs, 714m
929vs, 714vs
893s, 730vs
892m, 725vs
892s, 728vs
1083vs, 716vs
33.3, 30.4 [2J(PP) 0]
56.7
639s
53.9 [1J(PSe) 764]
551m, 522m
638s, 556m, 524m
629vs
551s
645m, 555s
633s, 627s, 613s
56.8 [5J(PP) 13], 53.4 [5J(PP) 13, 1J(PSe) 764]
57.9
3147w
53.3 [1J(PSe) 792]
3127vw
3143vw
3368m
56.1 [5J(PP) 22], 53.0 [5J(PP) 22, 1J(PSe) 792]
60.4
1
279–280 ЊC. 31P NMR (CDCl3): δ 39.0 and [2J(PP) 13, J(PPt)
PPh2Cl with NH(SiMe3)2.17 Surprisingly, little advantage has
been taken of the ease of P᎐N bond-forming reactions in
the synthesis of new phosphines, in part perhaps because of
assumptions about the lability of the P᎐N bond. We have used
this route to synthesize a range of diphosphine systems with
amino spacers to aromatic backbones. Deprotonating the
amines attached to the appropriate aromatic backbones, i.e.
3,4-diaminotoluene, 1,2-diaminobenzene, 1,8-diaminonaphtha-
lene or 1,2-diaminoethane with triethylamine in the presence
of a catalytic amount of 4-(dimethylamino)pyridine [equation
(1), R = aryl] works effectively and we obtained the new
3943 Hz] and 36.3 [2J(PP) 13, J(PPt) 3887 Hz]. IR (KBr disc,
1
cmϪ1): 3448w, 3211w, 3051vw, 2921vw, 2860vw, 1512w, 1481vw,
1459w, 1436vs, 1377vw, 1314w, 1129vw, 1101s, 1022vw, 998vw,
972vw, 891w, 815vw, 747m, 691vs, 583vw, 547w, 532m, 512vs,
486w, 469w, 444w, 317w, 305w, 283w, 253m and 246vs. FAB
mass spectrum: m/z 779, [M ϩ Na]ϩ; 756, Mϩ; 721, [M Ϫ Cl]ϩ;
and 684/685, [M Ϫ 2Cl]ϩ [Found: C, 47.9; H, 3.6; N, 3.5.
(C31H28Cl2N2P2Pt)2ؒCH2Cl2 requires C, 47.4; H, 3.7; N, 3.5%].
[(AuCl)2{MeC6H3(NHPPh2)2-3,4}]. This was prepared in the
same way as the palladium complex using [AuCl(tht)] (60 mg,
187 µmol) and 3,4-bis(diphenylphosphinoamino)toluene 2 (47
mg, 96 µmol) to give a crude yield of 66 mg (72%), m.p. 146–
2NEt3
PPh2Cl ϩ R(NH2)2
R(NHPPh2)2 ϩ 2NEt3HCl (1)
149 ЊC. NMR (CDCl3): 31P, δ 60.9 and 59.6; H, δ 7.21 (m,
1
phosphines in good yield. 1,2-Bis(diphenylphosphinoamino)-
benzene 1 and 3,4-bis(diphenylphosphinoamino)toluene 2 are
air stable indefinitely.
aromatic), 6.60 (m, aromatic), 6.50 (d, aromatic), 6.44 (d, aro-
matic), 5.45 (1 H, br s, NH), 5.33 (1 H, br s, NH) and 1.90 (3 H,
s, CH3). IR (KBr disc, cmϪ1): 3357vw, 2950vw, 2863vw, 1509s,
1436s, 1376w, 1294w, 1261vw, 1211vw, 1160vw, 1105s, 1027vw,
998vw, 969vw, 917vw, 886vw, 808w, 746m, 691vs, 531m, 498m,
419vw, 398w, 375vw, 352m, 334m, 326m, 303vs, 290s, 279vs,
254m, 247m and 227w. FAB mass spectrum: m/z 977,
[M ϩ Na]ϩ; and 919, [M Ϫ Cl]ϩ (Found: C, 38.5; H, 3.2; N,
2.6. C31H28Au2Cl2N2P2 requires C, 39.0; H, 2.9; N, 2.9%).
Compounds 1 and 2 gave satisfactory microanalyses; 1 dis-
played a singlet in the 31P-{1H} NMR spectrum (δ 32.5) and the
1
expected H NMR spectrum (NH as a doublet at δ 4.35), 2
displayed two peaks in the 31P-{1H} NMR spectrum (δ 33.3 and
30.4) and a similar 1H NMR spectrum (NH as two doublets at δ
4.38 and 3.89). The NMR shifts of 1 and 2 may be compared
1
with those of 1,2-(Ph2PCH2)2C6H4 [31P-{1H}, δ Ϫ13.5; H for
CH2 at δ 3.31]; the amino groups in 1 and 2 contribute to a
significant difference in δ values between the carbon- and
nitrogen-based systems. It is noteworthy that the δP values in
are similar to that of Ph2PNHPPh2 (δ 33) suggesting that the
neighbouring atom dominates the shift. Assignment of their IR
spectra is difficult, but we can identify ν(NH) at 3328 and 3329
cmϪ1 and ν(PN) at 904 and 887 cmϪ1 for 1 and 2 respectively.
The positive-ion FAB mass spectra gave the expected parent
ions with appropriate isotopes distributions.
Crystallography
Details of the data collections and refinements are summarised
in Table 1. Data were collected at room temperature using Cu-
Kα (λ = 1.541 78 Å) and ω scans with a Rigaku AFC7S diffract-
ometer. Intensities were corrected for Lorentz-polarisation and
for absorption (DIFABS15 or ψ-scans). The structures were
solved by the heavy-atom method or by direct methods. For
compound 4 only extremely small crystals were available, which
led to a low number of observed reflections; only the P, Se and
N atoms were refined anisotropically. In the other cases all of
the non-hydrogen atoms were refined anisotropically. In 6 and 7
the absolute chirality was tested using the Flack parameter
which refined to 0.02(1) and 0.08(1) respectively. In cis-
[Mo(CO)4{MeC6H3(NHPPh2)2-3,4}] the methyl substituent on
the aryl backbone was disordered over two sites with refined
occupancies of 70 and 30%. In cis-[PtCl2{MeC6H3(NHPPh2)2-
3,4}] the dichloromethane solvate was present as two 50%
occupancy molecules. The positions of the hydrogen atoms
were idealised. Refinements were by full-matrix least squares
based on F using TEXSAN.16
The compound R2PNHPR2 may be oxidised by elemental
sulfur or selenium in toluene at reflux to form Ph2P(S)NH-
(S)PPh2 or Ph2P(Se)NH(Se)PPh2.18 As expected the new
17
diphosphines described here were readily oxidised by sulfur or
selenium at room temperature in tetrahydrofuran or toluene
[equation (2)]. We tested this reaction using simple phenyl com-
thf or ether
R(NHPPh2)2 ϩ E
R[NHP(E)Ph2]2
E = ¹S8 or 2Se (2)
₄

pounds as well as naphthyl and ethyl backbones. The NMR and
selected IR data for the new compounds are given in Table 1.
The 31P-{1H} NMR spectra of 3, 6 and 9 displayed the expected
singlets (δ 56.7, 57.9 and 60.4 respectively) and are shifted
Atomic coordinates, thermal parameters and bond lengths
and angles have been deposited at the Cambridge Crystallo-
graphic Data Centre (CCDC). See Instructions for Authors,
J. Chem. Soc., Dalton Trans., 1997, Issue 1. Any request to the
CCDC for this material should quote the full literature citation
and the reference number 186/431.
1
around 30 ppm downfield on going from PIII to PV. The H
NMR spectra contain the NH resonance (as a doublet at δ 5.80,
6.76 and 3.28). Compounds 4 and 7 showed singlets with selen-
1
ium satellites in the 31P-{1H} NMR spectrum [δ 53.9, J(PSe)
1
764 and 53.3, J(PSe) 792 Hz]. The ν(PN) and ν(PE) vibra-
Results and Discussion
tions are assigned in Table 1.
The most efficient route for preparing Ph2PNHPPh2 with
an amino spacer between the two phosphines is by treating
The mixed sulfur–selenium compound 5 has also been pre-
pared by treating 1 with 1 mol of sulfur for 1 h followed by 1
J. Chem. Soc., Dalton Trans., 1997, Pages 1611–1616
1613

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Fig. 1 Crystal structure of compound 4
Fig. 4 Crystal structure of cis-[Mo(CO)4{MeC6H3(NHPPh2)2-3,4}].
Only the 70% occupancy substituent methyl group is shown
Fig. 2 Crystal structure of compound 6; 7 and 8 are isomorphous
Fig. 5 Crystal structure of cis-[PdCl2{MeC6H3(NHPPh2)2-3,4}]
are given in Table 3. In 4 the amino nitrogen atoms are
approximately coplanar with the aryl backbone with one phos-
phorus also lying in this plane and the other phosphorus atom
above the aryl backbone plane (Fig. 1). However, in 6–8 (which
are isomorphous) a rather more symmetric arrangement is
adopted (Fig. 2) with the phosphorus atoms being on opposite
sides of the naphthalene plane. The pyramidalisation at nitro-
gen leads to these structures being chiral. This is most obvious
in the case of 7, where the (R,R) conformation is clearly identi-
fied. However in 6 although the pyramidalisation is clear at
N(1) (R form) it is less pronounced at N(8). In 9 the crystal
structure reveals (Fig. 3) two independent half molecules both
of which are located on crystallographic centres of symmetry.
There is a weak intermolecular hydrogen bond between the two
independent molecules [H(ln*) ؒ ؒ ؒ S(2) 2.48, N(1*) ؒ ؒ ؒ S(2) 3.50
Å, N(1*)᎐H(ln*) ؒ ؒ ؒ S(2) 144Њ].
Fig. 3 Crystal structure of compound 9
mole of selenium in tetrahydrofuran [equation (3)]. Compound
thf or ether
C6H4(NHPPh2)2 ϩ ¹S8 ϩ Se
₈

C6H4[NHP(S)Ph2][NHP(Se)Ph2] (3)
5 showed two doublets with selenium satellites in the 31P-{1H}
NMR spectrum {δ (31P) 56.79 [5J(PP) 13] and 53.39 [1J(PSe) 764
Hz]}.
Compounds 3–8 can easily be recrystallised from
dichloromethane–diethyl ether; 9 was recrystallised from
methanol or dichloromethane-diethyl ether. All the oxidised
compounds in Table 1 are colourless.
The crystal structures of compounds 4 and 6–9 confirmed
the proposed formulations; comparative selected bond lengths
3,4-Bis(diphenylphosphinoamino)toluene reacted immedi-
ately with [Mo(CO)4(pip)2] to displace the piperidines and form
1614
J. Chem. Soc., Dalton Trans., 1997, Pages 1611–1616

View Article Online
Table 2 Details of the crystal data and refinements
cis-[Mo(CO)4-
{MeC6H3-
(NHPPh2)2}]
cis-[PdCl2-
{MeC6H3-
(NHPPh2}2]
Compound
4
6
7
8a
C34H28N2P2Se2 C34H28N2P2Se C26H26N2P2S2
9
Empirical formula
M
C30H26N2P2Se2 C34H28N2P2S2
C35H28MoN2O4P2 C32H30Cl4N2P2Pd
634.42
590.68
684.48
492.57
698.5
752.8
Colour, habit
Crystal size/mm
Clear, plate
0.15 × 0.15 ×
0.10
Clear, prism
0.15 × 0.23 ×
0.32
Clear, plate
0.20 × 0.10 ×
0.25
Clear, cube
0.24 × 0.26 ×
0.26
Clear, block
0.20 × 0.20 ×
0.26
Clear, needle
0.25 × 0.03 × 0.03 0.10 × 0.10 ×
0.20
Clear, block
Crystal system
Space group
a/Å
b/Å
c/Å
α/Њ
β/Њ
Monoclinic
C2/c (no. 15)
23.236(11)
9.061(14)
26.275(9)
Monoclinic
P21 (no. 4)
9.809(4)
15.942(6)
10.381(4)
Monoclinic
P21 (no. 4)
9.832(4)
16.030(3)
10.454(4)
Monoclinic
P21 (no. 4)
9.828(5)
15.987(4)
10.417(5)
Triclinic
P1 (no. 2)
Triclinic
P1 (no. 2)
Monoclinic
P21/n (no. 14)
17.385(5)
8.760(3)
25.289(2)
¯
¯
12.345(3)
12.698(2)
9.316(3)
105.05(2)
107.92(2)
103.44(2)
1262
2
1.30
3.22
516
10.718(2)
15.066(2)
10.214(1)
99.21(1)
93.27(1)
85.43(1)
1621
2
1.43
4.57
712
96.44(4)
116.19(3)
116.47(3)
116.35(3)
109.68(1)
γ/Њ
U/Å3
5497
8
1.53
4.63
2544
3061
1456
2
1.35
2.89
616
2263
1475
2
1.54
4.46
688
2285
1467
2
3626
4
1.38
7.85
1520
5809
Z
Dc/g cmϪ3
µ(Cu-Kα)/mmϪ1
F(000)
Independent
reflections
3032
4812
Observed reflections 1245b
Data: parameter ratio 7.7
Minimum, maximum 0.71, 1.0
transmission
1827c
5.1
0.25, 1.0
2197c
6.1
0.87, 1.0
2519c
8.7
0.63, 1.0
2680d
6.58
0.88, 1.0
3666b
9.21
0.48, 1.0
P in weighting scheme 0.004
0.003
0.007
0.003
0.007
0.003
Final R, RЈ
Largest ∆/σ
0.095, 0.055
0.05
0.060, 0.044
0.06
0.024, 0.026
0.01
0.073, 0.066
0.02
0.042, 0.040
0.04
0.082, 0.065
0.57
Largest difference
0.72, Ϫ0.77
0.39, Ϫ0.35
0.20, Ϫ0.18
0.39, Ϫ0.47
0.49, Ϫ0.29
0.84, Ϫ1.39
peak, hole/e ÅϪ3
a
The sulfur and selenium atoms were disordered, although a full data set was obtained no refinement resulting in meaningful bond lengths and
angles was possible. b I >1.5σ(I ). c I >3.0σ(I ). d I >2.0σ(I ).
Table 3 Comparative selected bond lengths (Å) and angles (Њ) for
compounds 4, 6, 7 and 9. For 4, 6 and 7 the different P᎐E/P᎐N, etc.
values are for the related bonds within the same molecule, whilst for 9
there are two independent half molecules with the one unique par-
ameter reported for each independent molecule
Table 4 Comparative selected bond lengths (Å) and angles (Њ) for the
molybdenum and palladium complexes; L = MeC6H3(NHPPh2)2-3,4
cis-[Mo(CO)4L]
cis-[PdCl2L]
M᎐P(1)
M᎐P(2)
2.516(2)
2.471(2)
1.688(6)
1.717(6)
1.415(9)
1.456(9)
1.382(10)
2.234(2)
2.245(2)
1.700(7)
1.681(8)
1.462(11)
1.407(10)
1.386(11)
4
6
7
9*
P(1)᎐N(1)
P(2)᎐N(2)
N(1)᎐C(1)
N(2)᎐C(2)
C(1)᎐C(2)
P᎐E
P᎐N
C᎐N
2.081(6)
2.107(5)
1.700(13)
1.638(13)
1.400(20)
1.413(19)
1.951(4)
1.957(4)
1.659(7)
1.655(7)
1.469(10)
1.464(1)
2.112(2)
2.111(8)
1.646(4)
1.676(4)
1.449(6)
1.439(6)
1.936(3)
1.943(2)
1.649(5)
1.654(5)
1.479(8)
1.523(8)
P(1)᎐M᎐P(2)
84.6(1)
115.6(2)
113.9(2)
128.4(5)
114.7(5)
124.5(7)
120.5(6)
91.31(8)
114.0(2)
117.6(3)
113.2(5)
128.9(6)
118.7(8)
126.0(9)
M᎐P(1)᎐N(1)
M᎐P(2)᎐N(2)
P(1)᎐N(1)᎐C(1)
P(2)᎐N(2)᎐C(2)
N(1)᎐C(1)᎐C(2)
N(2)᎐C(2)᎐C(1)
N᎐P᎐E
C᎐N᎐P
115.8(5)
114.3(5)
127.3(12)
124.5(12)
117.6(5)
114.2(3)
121.0(6)
121.6(6)
114.2(1)
116.8(2)
122.8(3)
120.8(3)
119.1(2)
118.3(2)
121.2(5)
123.5(4)
E ؒ ؒ ؒ E
anti
anti
anti
anti
conformation
Compound 2 reacts with [MCl2(cod)] to form the expected
seven-membered chelate complex [equation (5), M = Pd or Pt].
* The second value of (e.g. P᎐E) comes from the second independent
molecule throughout.
[MCl2(cod)] ϩ MeC6H3(Ph2PNH)2-3,4
[PdCl2{MeC6H3(NHPPh2)2-3,4}] (5)
a seven-membered-ring metal complex with molybdenum as
shown in equation (4). Its crystal structure reveals (Fig. 4) a
The palladium complex displayed an AX system in the 31P-{1H}
NMR spectrum {δ 62.4 and 60.1 [2J(PP) 31 Hz]} with the two
phosphorus atoms coupling through the metal centre. Similarly
the platinum complex displays an AX spectrum with platinum
satellites in the 31P-{1H} NMR spectrum {δ 39.0 [2J(PP) 13,
[Mo(CO)4(pip)2] ϩ MeC6H3(Ph2PNH)2-3,4
[Mo(CO)4{MeC6H3(NHPPh2)2-3,4}] (4)
distorted octahedron with the carbonyl groups pushed away
slightly by the phenyl groups of the phosphorus atoms. The
seven-membered ring has some modest distortions from sym-
metric (Table 4) but (excluding the ME substituent) the mol-
ecule possesses approximate non-crystallographic C2 symmetry
about an axis passing through the Mo atom and the middle of
the C(1)᎐C(2) bond.
1
1J(PPt) 3943] and 36.3 [2J(PP) 13, J(PPt) 3887 Hz]}. The dif-
ference in the two inequivalent phosphorus peaks (∆δ = 2.91
ppm) for the free phosphine is reduced (∆δ = 0.27 ppm] for the
metal complex.
The crystal structure of the palladium complex reveals (Fig.
5) the seven-membered ring to have a similar geometry to that
J. Chem. Soc., Dalton Trans., 1997, Pages 1611–1616
1615

View Article Online
4 S. S. Sandhu, S. S. Sandhu and M. P. Gupta, Z. Anorg. Allg. Chem.,
1970, 377, 348.
in [Mo(CO)4{MeC6H3(NHPPh2)2-3,4}] with the aryl nitrogen
atoms coplanar with respect to the backbone and with this
backbone tilted with respect to the metal co-ordination plane;
the bond lengths and angles follow similar trends in these two
complexes.
5 A. Zanardo, R. A. Michelin, F. Pinna and G. Strukul, Inorg. Chem.,
1989, 28, 1648.
6 S. Gamguly and D. M. Roundhill, Organometallics, 1993, 12, 4825.
7 B. Chaudret, B. Delavaux and R. Poilblanc, Coord. Chem. Rev.,
1988, 86, 191.
8 L. Haiduc, C. Silvetru, H. W. Roesky, H. G. Schmidt and
M. Noltemeyer, Polyhedron, 1993, 12, 69.
9 J. S. Casas, A. Castineiras, I. Haiduc, A. Sanchez, J. Sordo and
E. M. Vazquez-Lopez, Polyhedron, 1994, 13, 2873.
10 A. Laguna, M. Laguna, A. Rojo and M. Nieves Fraile, J. Organ-
omet. Chem., 1986, 315, 269.
11 D. L. Hughes, N. J. Lazarowych, M. J. Maguire, R. H. Morris and
R. L. Richards, J. Chem. Soc., Dalton Trans., 1995, 5.
12 J. D. Woollins (Editor), Inorganic Experiments, VCH, Weinheim,
1994.
13 D. Drew and J. R. Doyle, Inorg. Synth., 1991, 28, 346.
14 R. Uson, A. Laguna and M. Laguna, Inorg. Synth., 1989, 26, 85.
15 N. Walker and D. Stuart, DIFABS, Acta Crystallogr., Sect. A, 1968,
24, 351.
Gold phosphines have been intensively investigated as new
antitumour drugs. More promising indications of anticancer
activity were shown by a series of digold phosphine complexes
e.g. [(AuCl)2(dppe)] (dppe = Ph2PCH2CH2PPh2).19 The reaction
of [AuCl(tht)] with 3,4-bis(diphenylphosphinoamino)toluene
led to [(AuCl)2{MeC6H3(NHPPh2)2-3,4}] in good yield as a
light brown powder. The complex displays two resonances in its
1
31P-{1H} NMR spectrum (δ 60.9 and 59.6) and the H NMR
spectrum showed NH as two broad singlets at δ 5.45 and 5.33.
Assignment of the IR spectrum is difficult, but we can identify
ν(NH) at 3357 cmϪ1 and ν(PN) at 886 cmϪ1 respectively. The
positive-ion FAB mass spectrum gave the expected parent ion
with appropriate isotope distribution and fragmentations.
16 TEXSAN, Crystal Structure Analysis Package, Molecular Structure
Corporation, Houston, TX, 1985 and 1992.
17 F. T. Wang, J. Najdzionek, K. L. Leneker, H. Wasserman and D. M.
Braitsch, Synth. React. Inorg. Metal-Org. Chem., 1978, 8, 119.
18 P. Bhattacharyya, A. M. Z. Slawin, D. J. Williams and J. D. Wool-
lins, J. Chem. Soc., Dalton Trans., 1995, 2489.
Acknowledgements
We are grateful to Exxon Chemicals for support.
19 O. M. Ni Dhubhgaill and P. J. Sadler, in Metal Complexes in Cancer
Therapy, ed. B. K. Keppler, VCH, Weinheim, 1993, p. 221.
References
1 A. M. Aguiar and M. G. R. Nair, J. Org. Chem., 1968, 33, 579.
2 M. Camalli, F. Caruso, S. Chaloupka, E. M. Leber, H. Rimml and
L. M. Venanzi, Helv. Chim. Acta, 1990, 73, 2263.
3 M. Camalli, F. Caruso, H. Rimml and L. M. Venanzi, Inorg. Chem.,
1995, 34, 673.
Received 2nd December 1996; Paper 6/08141J
1616
J. Chem. Soc., Dalton Trans., 1997, Pages 1611–1616