Organometallics
ARTICLE
(b) A portion of 30 mg (0.041 mmol) of [Fe{η5-C5H4B(NMe2)}2Pt-
(PEt3)2] (18) and 18.2 mg (0.0827 mmol, 2 equiv) of 21 were added to
an NMR tube and dissolved in 0.5 mL of benzene-D6. The solution was
heated to 80 °C while the progress of the reaction was monitored by 1H
NMR spectroscopy. After 1 h, the signals of 21 could no longer be
detected. Analogous workup (see above) afforded the product again
contaminated with e5% of [Pt(PEt3)3].
After 5 d the product was isolated as orange-yellow crystals (16 mg,
0.017 mmol, 42%), after washing with pentane (1 mL, ꢀ100 °C) and
drying under vacuum. The product thus obtained contains a small
amount of 14 (<5% by NMR spectroscopy).
1H NMR (500.130 MHz, C6D6): δ 0.99 (m, 9H, PCH2CH3), 1.09
(m, 9H, PCH2CH3), 1.62 (m, 6H, PCH2CH3), 1.85 (m, 6H, PCH2CH3),
2.37 (m, 3H, {B}CdC{B}CH3), 2.76 (s, 3H, NCH3), 2.79 (s, 3H,
NCH3), 2.83 (dd, 4JHꢀPcis = 8 Hz, 4JHꢀPtrans = 2 Hz, 3JHꢀPt = 38 Hz, 3H,
{Pt}CtCCH3), 2.90 (s, 3H, NCH3), 3.01 (s, 3H, NCH3), 4.13ꢀ4.99
ppm (m, 8H, C5H4). 11B{1H} NMR (160.462 MHz, C6D6): δ 40.9
ppm (br). 13C{1H} NMR (125.758 MHz, C6D6): δ 8.76 (m, PCH2CH3),
1H NMR (500.130 MHz, C6D6): δ 0.20 (s, 9H, CtCSiCH3), 0.33
(s, 9H, CdCSiCH3), 2.55 (s, 3H, NCH3), 2.56 (s, 3H, NCH3), 2.62
(s, 3H, NCH3), 2.67 (s, 3H, NCH3), 4.11 (m, 2H, C5H4), 4.17 (m, 1H,
C5H4), 4.21 (m, 1H, C5H4), 4.21ꢀ4.26 (m, 4H, C5H4), 5.85 (d, 1JHꢀH
=
16 Hz, 1H, C2H2), 7.60 ppm (d, JHꢀH = 16 Hz, 1H, C2H2). 11B{1H}
NMR (160.462 MHz, C6D6): δ 41.1 ppm (vbr). 13C{1H} NMR (125.758
MHz, C6D6): δ 0.14 (s, SiCH3), 1.59 (s, SiCH3), 40.30 (s, NCH3), 40.49
(s, NCH3), 41.83 (s, NCH3), 41.90 (s, NCH3), 70.28 (s, C5H4), 70.97
(s, C5H4), 71.07 (s, C5H4), 72.05 (s, C5H4), 72.23 (s, C5H4), 72.44
(s, C5H4), 78.04 (s, C5H4), 78.19 (s, C5H4), 98.18 (s, CtCSi), 106.63
(s, CtCSi), 110.89 (s, C2H2), 147.28 (s, C2H2), 164.78 (vbr, BCdC-
{B}Si), 165.63 ppm (vbr, BCdC{B}Si).
8.90 (m, PCH2CH3), 15.67 (dd, JCꢀP = 14 Hz, JCꢀP
= 9 Hz,
1
3
cis
3
trans
1
{Pt}CtCCH3), 19.75 (s, BCdC{B}CH3), 20.99 (dd, JCꢀP = 22 Hz,
3JCꢀP = 4 Hz, PCH2CH3), 21.30 (dd, JCꢀP = 21 Hz, JCꢀP = 4 Hz,
1
3
PCH2CH3), 40.73 (s, NCH3), 40.89 (s, NCH3), 41.13 (s, NCH3), 42.83
2
cis
(m, NCH3), 69.3ꢀ80.1 (m, vbr, C5H4), 121.57 (dd, JCꢀP = 68
Hz,2JC2ꢀP
= 10 Hz, JCꢀPt = 286 Hz, {Pt}CtCCH3), 123.35
trans
1
cis
trans
1
(dd, JCꢀP = 65 Hz,2JCꢀP
= 7 Hz, JCꢀPt = 268 Hz,
{Pt}CtCCH3), 142.67 (m, vbr, BCdCB), 144.78 ppm (m, vbr,
Synthesis of [Fe{η5-C5H4B(NMe2)}2{Me3Si}CdCꢀC6H4ꢀCtCꢀSiMe3]
(17). (a) A Young NMR tube was loaded with 11.4 mg (0.0170 mmol) of
[Pt(PEt3)4] and heated to 60 °C for 20 min under vacuum. To the resulting
red oil were added 50 mg (0.17 mmol) of [Fe{η5-C5H4B(NMe2)}2] (3),
69.1 mg (0.255 mmol, 1.5 equiv) of 1,4-bis[2-(trimethylsilyl)ethynyl]ben-
zene (21), and 0.5 mL of benzene-D6, and the orange-yellow solution
was heated to 80 °C. Within 2 d the starting diborane(4) precursor was
consumed completely, as monitored by NMR spectroscopy. After that
the solvent was pumped off under reduced pressure, and the remaining
dialkyne was removed by sublimation at 100 °C under high vacuum.
The orange residue was extracted with hexanes (2 ꢁ 3 mL), before the
suspension was filtered, concentrated, and cooled to ꢀ30 °C. The
yellow solid thus produced was washed with pentane (2 ꢁ 1 mL,
ꢀ100 °C) and dried in vacuo, yielding the product as a yellow solid
(65.0 mg, 0.115 mmol, 68%).
BCdCB). 31P{1H} NMR (202.456 MHz, C6D6): δ 10.93 (d, JPꢀPt
=
1
3261 Hz, 2JPꢀP = 41 Hz, PtPCH2CH3), 12.79 ppm (d, 1JPꢀPt = 3243 Hz,
2JPꢀP = 41 Hz, PtPCH2CH3). IR (neat, cmꢀ1): 1557 (w, νBCdCB), 1744
(w, br, ν{Pt}CtC). Anal. Calcd (%) for C32H56B2FeP2Pt(803.29):C47.84,
H 7.02, N 3.49. Found: C 48.35, H 6.90, N 3.56.
Synthesis of [(3,4-η2-Fe{η5-C5H4B(NMe2)}2{Ph}CdCꢀCtCꢀPh)
Pt(PEt3)2] (24). An NMR tube was filled with 30 mg (0.041 mmol) of
[Fe{η5-C5H4B(NMe2)}2Pt(PEt3)2] (18), 7.9 mg (0.039 mmol, 0.95
equiv) of 1,4-diphenylbutadiyne (20), and 0.5 mL of benzene-D6. The
orange-red solution was heated to 80 °C while monitored by NMR
spectroscopy. After 1 h no further decrease of the signals of 20 could be
observed. Thereafter the solvent was evaporated in vacuo at room tempera-
ture before removing the excess dialkyne at 70 °C. The resulting orange-red
residue was extracted with hexanes (2 ꢁ 5 mL) and filtered. The orange-
colored solution was concentrated to one-third of the original volume and
cooled to ꢀ30 °C. The product was isolated as orange-yellow crystals
(21 mg, 0.023 mmol, 55%) after two days and recrystallized from hexanes
at ꢀ30 °C to obtain crystals suitable for X-ray diffraction.
(b) A 20 mg (0.028 mmol) sample of [Fe{η5-C5H4B(NMe2)}2Pt-
(PEt3)2] (18) and 11.2 mg (0.0410 mmol, 1.5 equiv) of 21 were filled into
an NMR tube and dissolved in 0.5 mL of benzene-D6. The yellow solution
was heated to 80 °C, and after 1 h no signal for 18 could be detected by
1H NMR spectroscopy. The reaction was worked up analogously (see
above), providing the target product in comparable yield.
1H NMR (600.130 MHz, C6D6): δ 0.89 (m, 9H, PCH2CH3), 0.93
(m, 9H, PCH2CH3), 1.33 (m, 3H, PCH2CH3), 1.43 (m, 6H, PCH2CH3),
1.61 (m, 3H, PCH2CH3), 2.60 (s, 3H, NCH3), 2.61 (s, 3H, NCH3), 2.77
(s, 3H, NCH3), 2.78 (s, 3H, NCH3), 4.32 (m, 1H, C5H4), 4.34 (m, 1H,
C5H4), 4.35 (m, 2H, C5H4), 4.37 (m, 1H, C5H4), 4.43 (m, 1H, C5H4), 4.60
(m, 1H, C5H4), 4.87 (m, 1H, C5H4), 7.02 (m, 1H, {Pt}CtCC6H5), 7.07
(m, 1H, BCdC{B}C6H5), 7.21 (m, 2H, {Pt}CtCC6H5), 7.27 (m, 2H,
BCdC{B}C6H5), 7.32 (m, 2H, {Pt}CtCC6H5), 7.86 ppm (m, 1H,
BCdC{B}C6H5).11B{1H}NMR(160.462MHz, C6D6):δ39.1ppm(br).
13C{1H} NMR (150.902 MHz, C6D6): δ 8.67 (m, PCH2CH3), 8.83
(m, PCH2CH3), 20.20 (dd, 1JCꢀP = 9 Hz, 3JCꢀP = 3 Hz, PCH2CH3), 21.38
1H NMR (500.130 MHz, C6D6): δ 0.15 (s, 9H, CdCSiCH3), 0.27
(s, 9H, CtCSiCH3), 2.48 (s, 3H, NCH3), 2.54 (s, 3H, NCH3), 2.70
(s, 3H, NCH3), 2.74 (s, 3H, NCH3), 4.16 (m, 1H, C5H4), 4.20 (m, 1H,
C5H4), 4.26 (m, 1H, C5H4), 4.27ꢀ4.30 (m, 4H, C5H4), 4.42 (m, 1H,
C5H4), 7.35 (m, 2H, C6H4), 7.58 ppm (m, 2H, C6H4). 11B{1H} NMR
(160.462 MHz, C6D6): δ 39.9 ppm (vbr). 13C{1H} NMR (125.758 MHz,
C6D6): δ 0.16 (s, SiCH3), 2.69 (s, SiCH3), 40.87 (s, NCH3), 41.06
(s, NCH3), 41.82 (s, NCH3), 42.00 (s, NCH3), 70.64 (s, C5H4), 71.13
(s, C5H4), 72.01 (s, C5H4), 72.01 (s, C5H4), 72.18 (s, C5H4), 72.33
(s, C5H4), 77.58 (s, C5H4), 77.97 (s, C5H4), 94.21 (s, CtCSiCH3),
106.57 (s, CtCSiCH3), 121.33 (s, C6H4), 128.74 (s, C6H4), 131.87
(s, C6H4), 148.63 (s, C6H4), 159.92 (vbr, BCdC{B}Si), 170.35 ppm (vbr,
BCdC{B}Si). Anal. Calcd (%) for C30H42B2FeN2Si2 (564.31): C 63.85,
H 7.50, N 4.97. Found: C 63.32, H 7.85, N 4.85.
1
3
(dd, JCꢀP = 9 Hz, JCꢀP = 3 Hz, PCH2CH3), 40.63 (s, NCH3), 40.88
(s, NCH3), 42.05 (s, NCH3), 42.17 (s, NCH3), 70.27 (s, C5H4), 70.53
(s, C5H4), 71.42 (s, C5H4), 71.95 (s, C5H4), 71.96 (s, C5H4), 72.18
(s, C5H4), 72.41 (br, C5H4quarternary), 76.65 (br, C5H4quarternary), 78.78
(s, C5H4), 79.92 (s, C5H4), 124.01 (m, {Pt}CtCC6H5), 124.75 (s, BCdC-
{B}C6H5), 126.92 (m, {Pt}CꢂCC6H5), 127.39 (m, {Pt}CtCC6H5),
127.56 (s, BCdC{B}C6H5), 130.50 (m, BCdC{B}C6H5), 130.88 (dd,
2JCꢀPcis = 72 Hz, 2JCꢀPtrans = 9 Hz, 1JCꢀPt = 289 Hz, {Pt}CtC), 134.26 (dd,
2JCꢀPcis = 65 Hz, 2JCꢀPtrans = 7 Hz, 1JPtꢀC = 253 Hz, {Pt}CtC), 143.34
(s, vbr, BCdC{B}C6H5), 144.15 (m, {Pt}CtCC6H5quarternary), 144.88
(m, BCdC{B}C6H5quarternary), 148.65 ppm (s, vbr, BCdC{B}C6H5).
Synthesis of [(3,4-η2-Fe{η5-C5H4B(NMe2)}2{Me}CdCꢀCtCꢀMe)
Pt(PEt3)2] (23). A 30 mg (0.041 mmol) portion of [Fe{η5-C5H4B-
(NMe2)}2Pt(PEt3)2] (18) and 3.1 mg (0.039 mmol, 0.95 equiv) of 2,
4-hexadiyne (19) were filled into an NMR tube and dissolved in 0.5 mL
of benzene-D6. The orange solution was heated to 60 °C, and the
reaction progress was monitored by NMR spectroscopy. After 1 h no
further decrease of the signals of 18 could be detected. The volatiles were
removed in vacuo, and the orange residue was extracted with pentane
(2 ꢁ 2 mL). The resulting suspension was filtered, concentrated to a
third of its original volume, and cooled to ꢀ30 °C for crystallization.
31P{1H} NMR (202.456 MHz, C6D6): δ 8.60 (d, 2JPꢀP = 33 Hz, 1JPꢀPt
=
3252 Hz, PtPCH2CH3), 10.94 ppm (d, 2JPꢀP = 33 Hz, 1JPꢀPt = 3410 Hz,
PtPCH2CH3). IR (neat, cmꢀ1): 1586 (w, νBCdCB), 1736 (w, ν{Pt}CtC).
Anal. Calcd (%) for C42H60B2FeN2P2Pt (927.43): C 54.39, H 6.52, N 3.02.
Found: C 54.04, H 6.66, N 3.08.
2880
dx.doi.org/10.1021/om200214w |Organometallics 2011, 30, 2869–2884