Inorganic Chemistry
ARTICLE
[{NCCl}2{NP(NC(NMe2)2)2}] (4). To a solution of [{NCCl}2{NPCl2}]
(7.2 g, 30 mmol) in tetrahydrofuran (70 mL) was added dropwise a solution
of 1,1,3,3-tetramethyl-guanidine (15.1 g, 131 mmol) over a period of 30 min
at 0-5 ꢀC. The reaction mixture was subsequently stirred at room
temperature for 24 h and filtered through a G4 frit. Removal of the solvent
from the filtrate in vacuo afforded a colorless precipitate. This was dissolved
in a small amount of acetonitrile and kept at 4 ꢀC. After 12 h, a colorless
crystalline product (3) was obtained. Yield: 9.1 g (75.5%). Mp. 140 ꢀC. 1H
NMR: δ 2.86 (s, 24H, NMe2). 31P{1H} NMR: δ -3.9 (s). ESI-MS m/z,
ion: 396.13. IR (KBr) cm-1: 3406 (b), 3008 (s), 2934 (m), 2160 (w), 1632
(s), 1525 (s), 1470 (m), 1403 (s), 1385 (s), 1341 (m), 1261 (s), 1154 (s),
1060 (m), 983 (s), 948 (s), 919 734 (m), 722 (s0, 647 (m), 531 (m), 467
(m). Anal. Calcd. for C12H24Cl2N9P (395.13): C, 36.37; H, 6.10; N, 31.81.
Found: C, 36.42; H, 6.18; N, 31.72.
Scheme 1
Scheme 2
[{NC(p-OC5H4N)}2{NP(NC(NMe2)2)2}] (5). An acetone solution
(50 mL) of 4-hydroxy pyridine (2.0 g, 21 mmol) and an excess of
K2CO3 (8.7 g, 63 mmol) was stirred for 1 h at room temperature in a N2
atmosphere. To this solution was added [{NCCl}2{NP{NC(NMe2)2}2]
(4.0 g, 10.0 mmol), and the solution was heated under reflux for 48 h.
Removal of the solvent at low pressure afforded a colorless residue. This
was redissolved in dichloromethane (100 mL) and filtered using a G-4 frit.
The light brown-colored solution, thus obtained, was concentrated to
10 mL and kept at 4 ꢀC overnight. A colorless crystalline needle-shaped
product resulted. Yield: 4.3 g (83%). Mp. 75 ꢀC. 1H NMR: δ 2.86 (s, 24H,
NMe2), 6.32 (d, 4H, aromatic), 8.74 (d, 4H, aromatic). 31P{1H} NMR:
δ 1.5 (s). ESI-MS m/z, ion: 514.25. IR (KBr) cm-1: 3395 (b), 3107 (w),
2928 (m), 1636 (s), 1563 (s), 1389 (m), 1342 (s), 1298 (s), 1180 (m),
1126 (s), 975 (m), 854 (m), 767 (m), 723 (m), 668 (m), 611 (m), 581
(m), 556(m), 469 (m). Anal. Calcd. for C22H32N11O2P (513.25): C,
51.45; H, 6.28; N, 30.00. Found: C, 51.57; H, 6.32; N, 29.91.
crystalline product identified as 7. Yield: 0.09 g (80%). Mp: 206 ꢀC(d).
UV/Visible: (CH2Cl2; λmax/nm (εmax/M-1cm-1)): 304 (2332), 281
(6024), 229 (22462). FT-IR ν/cm-1: 3462 (b), 1679 (s), 1584 (s),
1409 (m), 1261 (m), 1093 (m), 804 (s), 532 (m). 1H NMR: 2.25, 2.39,
2.44 (s, 18H, Pz-CH3), 5.68 (s, 3H, Pz-CH). 31P NMR: 1.0 (s). Anal.
Calcd for C17H21N9POPdCl: C, 37.79; H, 3.92; N, 23.33. Found: C,
37.42; H, 3.62; N, 23.46.
[{NC(3,5-Me2Pz)NHC(3,5-Me2Pz)}{NP(O)}]2 (9). To a solution of
[{NC(3,5-Me2Pz)}2{NP(3,5-Me2Pz)2}] (0.12 g, 0.25 mmol) in di-
chloromethane was added anhydrous K2PtCl4 (0.11 g, 0.26 mmol),
which was allowed to stir for 6 h at room temperature. It was then filtered
and the filtrate concentrated to about 3 mL. To this was added 6 mL of
n-hexane, which was kept at 0 ꢀC to obtain a crystalline product
[{NC(NMe2)}2{NHP(O)(3,5-Me2Pz)} {Cu(3,5-Me2PzH)2(Cl)}][Cl]
3
identified as 9. Yield: 0.06 g (77%). Mp: 120 ꢀC(d). FT-IR ν/cm-1
:
(6). To a solution of ligand 1 (0.056 g, 0.15 mmol) in dichloromethane
(40 mL) was added anhydrous CuCl2 (0.02 g, 0.15 mmol). After stirring
for 12 h at room temperature, the reaction mixture was filtered and
concentrated to a volume of 3 mL. To this solution was added 10 mL of
n-hexane, upon which a solid was deposited. This was filtered and dried.
Yield: 0.053 g (57%). Mp. 106-108 ꢀC. UV/Visible: (CH2Cl2; λmax/nm
(εmax/M-1 cm-1)): 823(125), 467(625), 331(shoulder; 2107),
241(30 000). Solution magnetic moment, μB = 1.51 μB (after applying
diamagnetic corrections). EPR (CH2Cl2/toluene, 1:1, 77K): g =
2.27; g^ = 2.08; A = 130 ꢀ 10-4cm-1. IR (KBr) cm-1: 2927 (m),
1607 (s), 1559 (s), 1405 (m), 1330 (m), 1293 (m), 1219 (m), 1177
(s), 1050 (s), 987 (m), 954 (m), 929 (m), 902 (m), 822 (m), 598 (s),
556 (s). Anal. Calcd. for C21H36N11POCuCl2 (622.15): C, 40.42; H,
5.81; N, 24.69. Found: C, 39.56; H, 5.92; N, 25.72.
2929 (b), 1714(s), 1606(s),1423(m), 1074(m), 972(m), 716(m),
1
494(m). H NMR: 2.30, 2.39, 2.57 (s, 12H, Pz-CH3), 5.71 (s, 2H,
Pz-CH). 31P NMR: -0.6 (s). Anal. Calcd for C24H30N14P2O3: C, 46.16;
H, 4.84; N, 31.40. Found: C, 46.20; H, 4.64; N, 31.55.
[{NC(OC5H4N)}2{NP(NC(NMe2)2)2} {PdCl2}] (10). To a solution
3
of 4 (0.10 g, 0.19 mmol) in acetonitrile (40 mL) was added Pd-
(CH3CN)2Cl2 (0.05 g, 0.19 mmol). After stirring for 12 h at room
temperature in a N2 atmosphere, the reaction mixture was filtered,
concentrated to a volume of 10 mL, and kept for slow evaporation. After
7 days, yellow colored crystals were obtained. Yield: 0.83 g (62%). Mp.
250 ꢀC. 31P{1H} NMR: δ 36.4 (s). ESI-MS m/z, ion: 692.10. IR (KBr)
cm-1: 3436 (b), 3112 (w), 2935 (w), 1641 (m), 1596 (s), 1521 (s),
1467 (m), 1405 (s), 1347 (s), 1321 (s), 1207 (m), 1131 (s), 1065 (w),
976 (s), 918 (m), 854 (m), 801 (m), 726 (m), 684 (m), 549 (m). Anal.
Calcd. for C22H32Cl2PdN11PO2 (689.09): C, 38.25; H, 4.67; N, 22.30.
Found: C, 38.32; H, 4.74; N, 22.13.
[{NC(NEt)2}{NC(3,5-Me2Pz)}{NP(O)(3,5-Me2Pz)} {Pd(3,5-Me2PzH)-
3
(Cl)}] (7). To a solution of ligand 2 (0.10 g, 0.22 mmol) in dichlor-
omethane (40 mL) was added Pd(PhCN)2Cl2 (0.08 g, 0.22 mmol).
After stirring for 12 h at room temperature, the reaction mixture was
filtered and concentrated to a volume of 3 mL. To this solution was
added 10 mL of n-hexane, upon which a solid was deposited. This was
filtered and dried. Yield: 0.11 g (84%). Mp. 70-72 ꢀC. IR (KBr) cm-
1: 2977 (m), 2929 (m), 2856 (w), 1653 (m), 1586 (s), 1478 (m), 1419
(m), 1300 (s), 1237 (m), 1083 (s), 967 (s), 896 (s), 806 (m), 749 (m),
607 (m), 552 (m). UV/Visible: (CH2Cl2; λmax/nm (εmax/M-1cm-1)):
793(15), 386(shoulder; 269), 257(14,676). Anal. Calcd. for C21H32-
N10POPdCl (612.12): C, 41.11; H, 5.25; N, 22.83. Found: C, 40.90;
H, 4.98; N, 22.01.
’ RESULTS AND DISCUSSION
Synthetic Aspects. The tetrachlorocarbophosphazene
[{NCCl}2{NPCl2}] was prepared according to a literature
procedure.8 Reaction of [{NCCl}2{NPCl2}] with Me2NCH2NMe2
proceeds in a regiospecific manner to afford [{NC(NMe2)}2-
{NPCl2}]. In the latter, while the carbon centers are blocked,
the phosphorus atom contains two reactive P-Cl bonds,
which can be elaborated readily8,10 (Scheme 1). Accordingly,
the reaction of [{NC(NMe2)}2{NPCl2}] with two equivalents
of the sodium salt of 3,5-dimethypyrazole in THF afforded the
compound [{NC(NMe2)}2{NP(3,5-Me2Pz)2}] (1; Scheme 2).
On the other hand, the reaction of [{NCCl}2{NPCl2}] with
4 mol of 3,5-dimethypyrazole in the presence of triethylamine,
[{NC(3,5-Me2Pz)2}{NP(O)(3,5-Me2Pz)}{Pd(Cl)}] (8). To a solution
of [{NC(3,5-Me2Pz)}2{NP(3,5-Me2Pz)2}] (0.10 g, 0.22 mmol) in
dichloromethane was added anhydrous PdCl2(PhCN)2 (0.08 g,
0.22 mmol), which was allowed to stir for 6 h at room temperature.
It was then filtered and the filtrate concentrated to about 3 mL. To this
was added 6 mL of n-hexane, which was kept at 0 ꢀC to obtain a
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dx.doi.org/10.1021/ic102415x |Inorg. Chem. 2011, 50, 2568–2579