L.D. Field et al. / Journal of Organometallic Chemistry 655 (2002) 146ꢃ
/157
155
3.3. Synthesis of bis(3,5-dimethyl-1-pyrazolyl)methane
(dmBPM) iron(II) complexes
(4, Mꢀ, C22H32N8ClFe, [Fe(dmBPM)2Cl]ꢀ), 407 (18),
369 (100), 353 (5), 341 (12), 330 (17), 313 (71).
3.4. Synthesis of tris(1-pyrazolyl)methane (TPM)
iron(II) complexes
3.3.1. Synthesis of [Fe(dmBPM)2Cl2] (6)
[Fe(dmBPM)2Cl2] (6) was synthesised using a mod-
ified method of Mani [13]. A solution of [FeCl2] (21 mg,
0.166 mmol) in warm ethanol (2 ml) was added drop-
wise to a stirred solution of dmBPM (4) (54 mg, 0.265
mmol) in warm ethanol (3 ml). The clear yellow solution
was heated and stirred for 10 min and a precipitate
began to form. The reaction mixture was allowed to
stand undisturbed overnight. The precipitate was col-
3.4.1. Synthesis of [Fe(TPM)2]2ꢀ(Clꢁ)2 (10)
[Fe(TPM)2]2ꢀ(Clꢁ)2 (10) was synthesised using a
modification of the method of Mani [13].
A yellow solution of [FeCl2] (45.6 mg, 0.360 mmol) in
warm ethanol (2 ml) was added drop-wise to a stirred
solution of TPM (2) (155 mg, 0.724 mmol) in warm
ethanol (3 ml) resulting in a light purple solution. The
reaction mixture was heated and stirred for 10 min, then
allowed to stand undisturbed overnight during which
time a precipitate formed. The precipitate was collected
by filtration and recrystallised from an ethanol and
acetone mixture and dried under reduced pressure to
give the product, [Fe(TPM)2]2ꢀ(Clꢁ)2 (10), as pale
purple crystals (150 mg, 75%).
lected by filtration, washed with ethanol (2ꢄ
hexane (2ꢄ ml), and dried in vacuo to give
[Fe(dmBPM)2Cl2] (6) as a white powder (49.7 mg, 56%).
/
1 ml) and
/2
M.p. decomposes at 230 8C, melts at 240ꢃ241 8C.
/
1H-NMR (400 MHz, d4-methanol, 228 K): d 6.30 (bs,
4H, H4 or H1?), 6.11 (bs, 4H, H4 or H1?), 2.64 (bs, 12H,
C3-CH3 or C5-CH3), 2.36 (bs, 12H, C3-CH3 or C5-
CH3). IR nmax cmꢁ1 (polyethylene, diffuse reflectance)
M.p. decomposes at 152 8C, melts at 319ꢃ320 8C.
/
350 (s, cis-FeÃ
N(BPM)) ppm. Mass spectrum (CI, CH4, m/z (%)):
535 (4, 1, C22H32N8Cl2Feꢀ1H,
Mꢀꢀ
1H), (100, 1Cl,
/
Cl), 322 (m, cis-FeÃ
/
Cl), 278 (s, FeÃ
/
1H-NMR (400 MHz, d4-methanol, 228 K): d 10.21 (s,
2H, H1?), 8.94 (s, 6H, H3 or H5(TPM)), 7.67 (s, 6H, H3
or H5(TPM)), 6.90 (s, 6H, H4(TPM)) ppm. Mass
/
/
[Fe(dmBPM)2Cl2]ꢀ
/
499
Mꢀꢁ
/
spectrum (CI, NH3, m/z (%)): 260 {100, ((M2ꢀ)/2)ꢀ
/
C22H32N8C2Fe, [Fe(dmBPM)2Cl]ꢀ), 439 (12), 21 (5),
407(48).
18, [C20H20N12Cl2Fe]2ꢀꢀ
/
1Hꢀ
NH3, [Fe(TPM)2]2ꢀ
/
1Hꢀ
/
NH3}.
IR nmax cmꢁ1 (KBr powder, diffuse reflectance): 1410
(s), 1280 (s), 1251 (m), 1093 (s), 1060 (m), 785 (vs),
760 (s), 732 (vs), 706 (vs), 613 (m).
3.3.2. Synthesis of [Fe(dmBPM)2Cl]ꢀ(BPh4)ꢁ (8)
[Fe(dmBPM)2Cl]ꢀ(BPh4)ꢁ (8) was synthesised using
a modified method of Mani [13].
A solution of [FeCl2] (20 mg, 0.158 mmol) in hot
ethanol (5 ml) was added drop-wise to a stirred solution
of dmBPM (4) (61.2 mg, 0.299 mmol) in hot ethanol (5
ml). The clear yellow solution was refluxed as a solution
of NaBPh4 (60 mg, 0.175 mmol) in hot ethanol (5 ml)
was added slowly. As the NaBPh4 was added, the
solution became white and cloudy. The solution was
refluxed for 5 min, then allowed to stand undisturbed
overnight. The precipitate was collected by filtration,
3.4.2. Synthesis of [Fe(TPM)(NCS)2] (11)
A magenta solution of [Fe(NCS)2] (30.1 mg, 0.175
mmol) in warm methanol was added to a solution of
TPM (1) (40 mg, 0.187 mmol) in warm methanol (5 ml).
Upon addition of the [Fe(NCS)2] solution, the reaction
mixture changed colour from magenta, to bright yellow,
to orange, then finally to red. The reaction mixture was
allowed to stand for 3 h then the solvent was removed
under reduced pressure and the residue was washed with
washed with ethanol (2ꢄ
/
1 ml) and hexane (2ꢄ
/
2 ml),
and dried in vacuo to give [Fe(dmBPM)2Cl]ꢀ(BPh4)ꢁ
(8) as a white powder (84 mg, 75%).
hexane (3ꢄ2 ml) to remove excess ligand. The product,
[Fe(TPM)(NCS)2] (11), was obtained as a light purple
solid (24 mg, 35%).
/
M.p. decomposes at 180 8C, melts at 222ꢃ
/
230 8C.
1H-NMR (400 MHz, d4-MeOH, 250 K): d 8.90 (s,
1H, H1?), 7.94 (s, 3H, H3 or H5(TPM)), 7.85 (s, 3H, H3
or H5(TPM)), 6.61 (s, 3H, H4(TPM)) ppm. IR nmax
cmꢁ1 (KBr powder, diffuse reflectance): 3141 (w), 3115
(w), 3102 (w), 382 (w), 2058 (vs, CN(NCS)), 1653 (m),
1559 (s), 1540 (m), 1507 (s), 1456 (s), 1412 (m), 1291 (m),
1089 (m), 1058 (m), 868 (m), 790 (m), 764 (m), 751 (m),
606 (w, dNCS). Mass spectrum (CI, NH3, m/z (%)): 389
1H-NMR (400 MHz, d4-methanol, 228 K): d 7.36 (bs,
8H, ortho-BPh4), 7.11 (bs, 8H, meta-BPh4), 6.99 (bs,
4H, para-BPh4), 6.22 (bs, 4H, H4 or H1?), 6.11 (bs, 4H,
H4 or H1?), 2.62 (s, 12H, C3-CH3 or C5-CH3), 2.36 (s,
12H, C3-CH3 or C5-CH3) ppm. 13C{1H}-NMR (100
1
MHz, d4-MeOH, 230K): d 165.4 (q, JBC
ꢂ49.1 Hz,
/
ipso-BPh4), 150.2 (C3 or C5), 142.9 (C3 or C5), 137.5
(ortho-BPh4), 126.7 (meta-BPh4), 123.0 (para-BPh4),
107.6 (C4), 60.4 (C1?), 13.6 (C3-CH3 or C5-CH3), 11.6
(C3-CH3 or C5-CH3) ppm. IR nmax cmꢁ1 (polyethylene,
{12, Mꢀꢀ
3H}, 388
[Fe(TPM)(NCS)2]ꢀ
Mꢀꢁ
1NCSꢀ4Hꢀ1NH3, C12H10N7S2Feꢀ
[Fe(TPM)(NCS)]ꢀ4Hꢀ
1NH3), 344 (100, Mꢀꢁ
/
3, C12H10N8S2Feꢀ
{42, 2,
Mꢀꢀ
2H}, 382 (22), 371 (20), 346 (95,
4Hꢀ1NH3,
/
3H, [Fe(TPM)(NCS)2]ꢀ
/
/
C12H10N8S2Feꢀ2H,
/
/
diffuse reflectance) 352 (br, FeÃ
/
Cl), 278 (s, FeÃ
/
/
/
/
/
/
N(dmBPM)). Mass spectrum (CI, CH4, m/z (%)): 499
/
/
/
Field, Leslie D
