Thomas M.
Hood
,
Matthew R.
Gyton
and
Adrian B.
Chaplin
*
Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK. E-mail: a.b.chaplin@warwick.ac.uk
First published on 8th January 2020
The synthesis of macrocyclic variants of commonly employed phosphine-based pincer ligands derived from lutidine (PNP-14) and 2,6-dihydroxypyridine (PONOP-14) is described, where the P-donors are trans-substituted with a tetradecamethylene linker. This was accomplished using an eight-step procedure involving borane protection, ring-closing olefin metathesis, chromatographic separation from the cis-substituted diastereomers, and borane deprotection. The rhodium coordination chemistry of these ligands has been explored, aided by the facile synthesis of 2,2′-biphenyl (biph) adducts [Rh(PNP-14)(biph)][BArF4] and [Rh(PONOP-14)(biph)][BArF4] (ArF = 3,5-(CF3)2C6H3). Subsequent hydrogenolysis enabled generation of dihydrogen, ethylene and carbonyl derivatives; notably the ν(CO) bands of the carbonyl complexes provide a means to compare the donor properties of the new pincer ligands with established acyclic congeners.
The solid-state structures of 6a/6b demonstrate the adoption of distorted square pyramidal metal geometries, inferred from solution (Fig. 2). The methylene chains of the pincer ligands are skewed to one side of the basal plane, presumably to minimise steric buttressing with the biph ligand, and contorted to enable adoption of a weak γ-agostic interactions (⋯H– = 3.184(2) Å 6a; 2.925(5) Å, 6b).18 Agostic interactions of comparable magnitude are observed in 6a′/6b′ and closely related rhodium 2,2′-biphenyl complexes of a NHC-based macrocyclic pincer ligand.7,15
Reaction of 6a/b with dihydrogen (1 atm) in 1,2-difluorobenzene (DFB)17 resulted in hydrogenolysis of the biph ligand and formation of 7a/b [δ31P 65.9 (1JRhP = 120 Hz)/δ31P 211.5 (1JRhP = 127 Hz)], but elevated temperature and prolonged reactions times were required for complete conversion (t = 2 days/5 days at 85 °C, Scheme 2). In both cases, no organometallic intermediates were observed during this reaction and biphenyl was the sole by-product. The spectroscopic characteristics are consistent with formulation of 7a/b as C2 symmetric rhodium(I) dihydrogen complexes, with broad 2H resonances at δ −10.76/−8.51 that exhibit short spin–lattice relaxation (T1 = 45 ± 11/48 ± 6 ms) at 298 K (600 MHz, Ar) the most diagnostic.19 Subsequent reaction in situ with ethylene (1 atm) confers the corresponding C2 symmetric π-complexes 8a/8b [δ31P 53.0 (1JRhP = 125 Hz)/δ31P 199.1 (1JRhP = 129 Hz)], with concomitant formation of ethane, in quantitative spectroscopic yield within 5 min at RT. Coordination of ethylene is substantiated by chemically inequivalent 2H signals at δ 3.70/3.52 and 3.95/3.70, and 13C resonances at δ 55.0 (1JRhC = 12 Hz) and 59.5 (1JRhC = 11 Hz), which display appreciable coupling to 103Rh, for 8a and 8b respectively. Finally, C2 symmetric carbonyl compounds 9a/b [δ31P 67.5 (1JRhP = 122 Hz)/δ31P 210.8 (1JRhP = 128 Hz)] are obtained by substitution of ethylene on reaction of 8a/b with carbon monoxide (1 atm <5 min at RT), isolated from solution in 96/72% yield overall from 6a/b and fully characterised, including in the case of 9b in the solid state by X-ray diffraction (Fig. 2). The ν(CO) bands of rhodium(I) carbonyl derivatives are diagnostic reporter groups for the donor properties of pincer ligands.20,21 Comparison of the carbonyl bands of 9a/b with those of acyclic congeners 9a/b′,15,22 recorded under the same conditions, suggests PNP-14 and PONOP-14 are marginally weaker net donors than PNP-tBu and PONOP-tBu, respectively (Table 1). By reference to IR data reported for [Rh(PNP-iPr)(CO)][BArF4] (9a′′; PNP-iPr = 2,6-(iPr2PCH2)2C5H3N) and trends established for monodentate phosphines, these minor differences are in line with changes in the phosphine/phosphinite substituents alone.20,23
1 H NMR (600 MHz, C6D6): δ 5.80 (ddt, 3JHH = 16.9, 3JHH = 10.2, 3JHH = 6.7, 1H, CCH2), 5.02–5.08 (m, 1H, CHC2), 4.98–5.01 (m, 1H, CHC2), 2.90–2.97 (m, 4H, NCH2), 1.98–2.04 (m, 2H, C2CHCH2), 1.72–1.78 (m, 1H, CH2), 1.13–1.66 (m, 9H, CH2), 1.06 (d, 9H, 3JPH = 11.8, tBu), 1.00 (t, 6H, 3JHH = 7.1, NCH2C3).
13 C{ 1 H} NMR (151 MHz, C6D6): δ 139.2 (s, HCH2), 114.6 (s, CHH2), 44.5 (br, NCH2), 34.2 (s, H2CHCH2), 32.5 (d, 1JPC = 20, tBu{C}), 31.7 (d, JPC = 12, CH2), 29.5 (s, CH2), 29.4 (s, CH2), 27.6 (d, 2JPC = 16, tBu{CH3}), 26.6 (d, JPC = 18, CH2), 23.2 (d, 1JPC = 19, CH2), 15.2 (d, 4JPC = 2, NCH2H3).
31 P{ 1 H} NMR (243 MHz, C6D6): δ 73.3 (s).
1 H NMR (500 MHz, C6D6): δ 5.77 (ddt, 3JHH = 16.8, 3JHH = 10.0, 3JHH = 6.5, 1H, CCH2), 5.01–5.06 (m, 1H, CHC2), 4.97–5.01 (m, 1H, CHC2), 1.92–2.00 (m, 2H, C2CHCH2), 1.15–1.83 (m, 10H, CH2), 0.99 (d, 3JPH = 12.8, 9H, tBu).
13 C{ 1 H} NMR (126 MHz, C6D6): δ 139.1 (s, HCH2), 114.6 (s, CHH2), 34.1 (s, H2CHCH2), 32.4 (d, 1JPC = 29, tBu{C}), 31.1 (d, JPC = 11, CH2), 30.7 (d, 1JPC = 36, CH2), 29.2 (s, 2 × CH2), 25.9 (d, JPC = 15, CH2), 25.5 (d, 2JPC = 17, tBu{CH3}).
31 P{ 1 H} NMR (162 MHz, C6D6): δ 128.7 (s).
1 H NMR (500 MHz, CDCl3): δ 7.55 (t, 3JHH = 7.7, 1H, py), 7.19–7.24 (m, 2H, py), 5.72–5.85 (m, 2H, CCH2), 4.95–5.01 (m, 2H, CHC2), 4.91–4.95 (m, 2H, CHC2), 3.09–3.20 (m, 4H, pyC2), 1.97–2.06 (m, 4H, C2CHCH2), 1.67–1.85 (m, 2H, CH2), 1.49–1.62 (m, 4H, CH2), 1.21–1.38 (m, 14H, CH2), 1.16 (d, 3JPH = 13.3, 7.3H, tBu), 1.12 (d, 3JPH = 13.4, 10.7H, tBu), −0.05–0.77 (m, 6H, BH3). Some peaks duplicated because of diastereomers.
13 C{ 1 H} NMR (126 MHz, CDCl3): δ 154.4 (dd, 2JPC = 6, 4JPC = 1, py), 154.2 (dd, 2JPC = 5, 4JPC = 2, py), 138.97 (s, HCH2) 138.96 (s, HCH2), 136.8 (t, 4JPC = 2, py), 136.7 (t, 4JPC = 2, py), 123.3 (app t, JPC = 3, py), 123.2 (app t, JPC = 3, py), 114.5 (s, CHH2), 33.8 (s, H2CHCH2), 31.74 (d, 2JPC = 13, CH2), 31.70 (d, 2JPC = 13, CH2), 31.39 (d, 1JPC = 26, pyH2), 31.34 (d, 1JPC = 26, pyH2), 28.91 (d, 1JPC = 38, tBu{C}), 28.90 (d, 1JPC = 31, tBu{C}), 28.90 (s, CH2), 28.88 (s, CH2), 28.8 (br, CH2), 25.8 (t, 2JPC = 2, tBu{CH3}), 23.70 (s, CH2), 23.67 (s, CH2), 20.0 (d, 1JPC = 30, CH2). Some peaks duplicated because of diastereomers.
31 P{ 1 H} NMR (162 MHz, CDCl3): δ 33.7 (vbr, fwhm = 150 Hz).
HR ESI-MS (positive ion 4 kV): 554.4366, [M + Na]+ (calcd 554.4368) m/z.
1 H NMR (500 MHz, CDCl3): δ 7.65 (t, 3JHH = 7.9, 1H, py), 6.81 (d, 3JHH = 7.9, 1.0H, py), 6.80 (d, 3JHH = 7.9, 1.0H, py), 5.80 (ddt, 3JHH = 16.9, 3JHH = 10.3, 3JHH = 6.7, 2H, CCH2), 4.96–5.02 (m, 2H, CHC2), 4.93 (d, 3JHH = 10.1, 2H, CHC2), 2.08–2.24 (m, 2H, CH2), 2.04 (app q, 3JHH = 7, 4H, C2CHCH2), 1.79–1.92 (m, 2H, CH2), 1.67–1.78 (m, 4H, CH2), 1.33–1.47 (m, 12H, CH2), 1.29 (d, 3JPH = 14.1, 9.0H, tBu), 1.29 (d, 3JHH = 14.2, 9.0H, tBu), 0.08–0.92 (m, 6H, BH3). Some peaks duplicated because of diastereomers.
13 C{ 1 H} NMR (126 MHz, CDCl3): δ 158.1 (app t, JPC = 7, py), 142.09 (s, py), 142.05 (s, py), 139.07 (s, HCH2), 139.06 (s, HCH2), 114.5 (s, CHH2), 111.0 (d, 3JPC = 3, py), 110.8 (d, 3JPC = 3, py), 33.84 (s, H2CHCH2), 33.83 (s, H2CHCH2), 32.84 (d, 1JPC = 36, tBu{C}), 32.78 (d, 1JPC = 36, tBu{C}), 31.4 (s, CH2), 31.3 (s, CH2), 28.90 (s, CH2), 28.89 (s, CH2), 28.80 (s, CH2), 28.78 (s, CH2), 25.5 (d, 1JPC = 31, CH2), 25.4 (d, 1JPC = 31, CH2), 24.94 (d, 2JPC = 3, tBu{CH3}), 24.92 (d, 2JPC = 3, tBu{CH3}), 23.01, (s, CH2), 23.00 (s, CH2). Some peaks duplicated because of diastereomers.
31 P{ 1 H} NMR (162 MHz, CDCl3): δ 144.7 (vbr, fwhm = 160 Hz).
HR ESI-MS (positive ion 4 kV): 558.3953, [M + Na]+ (calcd 558.3950) m/z.
cis-5a (RF = 0.22). Yield: 553 mg (18%).
1 H NMR (500 MHz, CDCl3): δ 7.55 (t, 3JHH = 7.7, 1H, py), 7.23 (d, 3JHH = 7.8, 2H, py), 5.27–5.41 (m, 2H, CHCH), 3.07–3.21 (m, 4H, pyC2), 1.94–2.09 (m, 4H, C2CHCH), 1.80–1.92 (m, 2H, CH2), 1.47–1.67 (m, 4H, CH2), 1.23–1.45 (m, 14H, CH2), 1.12 (d, 3JPH = 13.3, 18H, tBu), 0.02–0.82 (m, 6H, BH3).
13 C{ 1 H} NMR (126 MHz, CDCl3): δ 154.5 (dd, 2JPC = 6, 4JPC = 2, py), 136.9 (t, 4JPC = 1, py), 131.1 (s, CHCH), 123.3 (app t, JPC = 3, py), 32.1 (s, H2CHCH), 31.2 (s, CH2), 31.1 (d, 1JPC = 12, pyH2), 28.9 (d, 1JPC = 31, tBu{C}), 28.7 (s, CH2), 27.5 (s, CH2), 25.8 (d, 2JPC = 2, tBu{CH3}), 23.5 (s, CH2), 19.3 (d, 1JPC = 30, CH2).
31 P{ 1 H} NMR (162 MHz, CDCl3): δ 33.8 (vbr, fwhm = 150 Hz).
HR ESI-MS (positive ion 4 kV): 526.4051, [M + Na]+ (calcd 526.4079) m/z.
trans-5a (RF = 0.22). Yield: 840 mg (27%).
1 H NMR (500 MHz, CDCl3): δ 7.54 (t, 3JHH = 7.7, 1H, py), 7.17 (d, 3JHH = 7.8, 2H, py), 5.23–5.41 (m, 2H, CHCH), 3.07–3.20 (m, 4H, pyC2), 1.99–2.07 (m, 4H, C2CHCH), 1.78–1.92 (m, 2H, CH2), 1.54–1.71 (m, 4H, CH2), 1.28–1.51 (m, 14H, CH2), 1.16 (d, 3JPH = 13.2, 18H, tBu), −0.15–0.73 (m, 6H, BH3).
13 C{ 1 H} NMR (126 MHz, CDCl3): δ 154.5 (dd, 2JPC = 5, 4JPC = 2, py), 136.7 (t, 4JPC = 2, py), 131.1 (s, CHCH), 123.2 (app t, JPC = 3, py), 31.9 (s, H2CHCH), 31.0 (d, 2JPC = 11, CH2), 30.8 (d, 1JPC = 26, pyH2), 29.0 (d, 1JPC = 31, tBu{C}), 28.6 (s, CH2), 27.2 (s, CH2), 25.9 (d, 2JPC = 2, tBu{CH3}), 23.5 (s, CH2), 19.8 (d, 1JPC = 30, CH2).
31 P{ 1 H} NMR (162 MHz, CDCl3): δ 34.0 (vbr, fwhm = 150 Hz).
HR ESI-MS (positive ion 4 kV): 526.4054, [M + Na]+ (calcd 526.4079) m/z.
cis-5b (RF = 0.21). Yield: 520 mg (33%).
1 H NMR (500 MHz, CDCl3): δ 7.67 (t, 3JHH = 7.9, 1H, py), 6.95 (d, 3JHH = 8.0, 2H, py), 5.29–5.32 (m, 2H, CHCH), 2.12–2.24 (m, 2H, CH2), 1.95–2.08 (m, 4H, C2CHCH), 1.65–1.85 (m, 6H, CH2), 1.30–1.48 (m, 12H, CH2), 1.28 (d, 3JPH = 14.1, 18H, tBu), 0.15–0.92 (m, 6H, BH3). Data for major isomer only.
13 C{ 1 H} NMR (126 MHz, CDCl3): δ 158.2 (d, 2JPC = 5, py), 142.3 (s, py), 131.0 (s, CHCH), 110.5 (d, 3JPC = 3, py), 32.8 (d, 1JPC = 37, tBu{C}), 32.1 (s, H2CHCH), 31.1 (d, 2JPC = 14, CH2), 28.7 (s, CH2), 27.7 (s, CH2), 25.5 (d, 1JPC = 31, CH2), 24.9 (d, 2JCH = 3, tBu{CH3}), 22.8 (s, CH2). Data for major isomer only.
31 P{ 1 H} NMR (162 MHz, CDCl3): δ 144.8 (vbr, fwhm = 150 Hz).
HR ESI-MS (positive ion 4 kV): 530.3644, [M + Na]+ (calcd 530.3639) m/z.
trans-5b (RF = 0.22). Yield: 540 mg (34%).
1 H NMR (500 MHz, CDCl3): δ 7.63 (t, 3JHH = 7.8, 1H, py), 6.76 (d, 3JHH = 7.9, 2H, py), 5.29–5.33 (m, 2H, CHCH), 2.16–2.33 (m, 2H, CH2), 1.96–2.09 (m, 4H, C2CHCH), 1.83–1.92 (m, 2H, CH2), 1.32–1.46 (m, 4H, CH2), 1.32–1.46 (m, 12H, CH2), 1.28 (d, 3JPH = 14.0, 18H, tBu), 0.11–0.85 (m, 6H, BH3). Data for major isomer only.
13 C{ 1 H} NMR (126 MHz, CDCl3): δ 158.2 (d, 2JPC = 6, py), 142.0 (s, py), 131.2 (s, CHCH), 110.1 (d, 3JPC = 3, py), 32.8 (d, 1JPC = 37, tBu{C}), 31.8 (s, H2CHCH), 31.2 (d, 2JPC = 14, CH2), 28.6 (s, CH2), 27.5 (s, CH2), 25.5 (d, 1JPC = 30, CH2), 24.9 (d, 2JPC = 3, tBu{CH3}), 23.4 (s, CH2). Data for major isomer only.
31 P{ 1 H} NMR (162 MHz, CDCl3): δ 143.4 (vbr, fwhm = 180 Hz).
HR ESI-MS (positive ion 4 kV): 530.3634, [M + Na]+ (calcd 530.3639) m/z.
cis-1a (20% EtOAc in hexane, RF = 0.20).
Following the general procedure using cis-5a (80.0 mg, 0.159 mmol) and [Rh(PPh3)3Cl] (7.4 mg, 8.0 μmol) in benzene (5 mL), the product was isolated as a white solid. Yield: 73.8 mg (92%).
1 H NMR (600 MHz, CDCl3): δ 7.55 (t, 3JHH = 7.7, 1H, py), 7.32 (d, 3JHH = 7.8, 2H, py), 3.16 (app d, 2JPH = 12, 4H, pyC2), 1.71–1.82 (m, 2H, CH2), 1.47–1.60 (m, 4H, CH2), 1.21–1.39 (m, 22H, CH2), 1.12 (d, 3JPH = 13.3, 18H, tBu), 0.11–0.72 (br, 6H, BH3).
13 C{ 1 H} NMR (151 MHz, CDCl3): δ 153.8 (dd, 2JPC = 4, 4JPC = 2, py), 136.6 (t, 4JPC = 2, py), 123.5 (app t, JPC = 3, py), 31.5 (d, 1JPC = 26, pyH2), 30.7 (d, 2JPC = 13, CH2), 28.9 (d, 1JPC = 31, tBu{C}), 28.0 (s, CH2), 27.87 (s, CH2), 27.85 (s, CH2), 27.8 (s, CH2), 25.7 (d, 2JPC = 2, tBu{CH3}), 22.7 (d, 3JPC = 2, CH2), 20.4 (d, 1JPC = 31, CH2).
31 P{ 1 H} NMR (243 MHz, CDCl3): δ 33.3 (vbr, fwhm = 130 Hz).
HR ESI-MS (positive ion 4 kV): 528.4204, [M + Na]+ (calcd 528.4211) m/z.
trans-1a (20% EtOAc in hexane, RF = 0.19).
Following the general procedure using trans-5a (840 mg, 1.67 mmol) and [Rh(PPh3)3Cl] (77.2 mg, 83.4 μmol) in benzene (50 mL), the product was isolated as a white solid. Yield: 818 mg (97%).
1 H NMR (500 MHz, CDCl3): δ 7.55 (t, 3JHH = 7.7, 1H, py), 7.21 (d, 3JHH = 7.8, 2H, py), 3.13–3.28 (m, 4H, pyC2), 1.75–1.86 (m, 2H, CH2), 1.52–1.68 (m, 4H, CH2) 1.38–1.50 (m, 4H, CH2), 1.26–1.35 (m, 18H, CH2), 1.10 (d, 3JPH = 13.3, 18H, tBu), 0.05–0.77 (m, 6H, BH3).
13 C{ 1 H} NMR (126 MHz, CDCl3): δ 154.7 (dd, 2JPC = 6, 4JPC = 1, py), 136.8 (t, 4JPC = 2, py), 123.0 (app t, JPC = 3, py), 31.5 (d, 1JPC = 26, pyH2), 30.8 (d, 2JPC = 13, CH2), 29.1 (d, 1JPC = 31, tBu{C}), 27.91 (s, CH2), 27.89 (s, CH2), 27.74 (s, CH2), 27.71 (s, CH2), 25.9 (d, 2JPC = 2, tBu{CH3}), 22.9 (d, 3JPC = 1, CH2), 20.1 (d, 1JPC = 31, CH2).
31 P{ 1 H} NMR (162 MHz, CDCl3): δ 33.9 (vbr, fwhm = 150 Hz).
HR ESI-MS (positive ion 4 kV): 528.4209, [M + Na]+ (calcd 528.4211) m/z.
Anal. Calcd for C29H59B2NP2 (505.37 g mol−1): C, 68.92; H, 11.77; N, 2.77; Found: C, 68.76; H 11.82; N, 2.69.
cis-1b (30% CH2Cl2 in hexane, RF = 0.19).
Following the general procedure using cis-5b (315 mg, 0.620 mmol) and [Rh(PPh3)3Cl] (27.2 mg, 29.4 μmol) in benzene (30 mL), the product was isolated as a white solid. Yield: 287 mg (91%).
1 H NMR (500 MHz, CDCl3): δ 7.67 (t, 3JHH = 7.9, 1H, py), 6.98 (d, 3JHH = 7.9, 2H, py), 2.12–2.25 (m, 2H, CH2), 1.63–1.82 (m, 6H, CH2), 1.27 (d, 3JPH = 14, 18H, tBu), 1.25–1.49 (m, 20H, CH2), 0.14–0.88 (m, 6H, BH3).
13 C{ 1 H} NMR (126 MHz, CDCl3): δ 158.2 (d, 2JPC = 5, py), 142.2 (s, py), 110.8 (d, 3JPC = 3, py), 32.9 (d, 1JPC = 36, tBu{C}), 30.6 (d, 2JPC = 13, CH2), 27.8 (s, 2 × CH2), 27.5 (s, CH2), 27.3 (s, CH2), 25.2 (d, 1JPC = 32, CH2), 24.9 (d, 2JPC = 3, tBu{CH3}), 22.1 (s, CH2).
31 P{ 1 H} NMR (162 MHz, CDCl3): δ 145.1 (vbr, fwhm = 142 Hz).
HR ESI-MS (positive ion 4 kV): 532.3791, [M + Na]+ (calcd 532.3796) m/z.
trans-1b (30% CH2Cl2 in hexane, RF = 0.20).
Following the general procedure using trans-5b (620 mg, 1.22 mmol) and [Rh(PPh3)3Cl] (56.5 mg, 61.1 μmol) in benzene (50 mL), the product was isolated as a white. Yield: 623 mg (95%).
1 H NMR (500 MHz, CDCl3): δ 7.64 (t, 3JHH = 7.8, 1H, py), 6.81 (d, 3JHH = 7.9, 2H, py), 2.13–2.29 (m, 2H, CH2), 1.85–1.96 (m, 2H, CH2), 1.69–1.83 (m, 4H, CH2), 1.38–1.47 (m, 4H, CH2), 1.28 (d, 3JPH = 13.9, 18H, tBu), 1.23–1.37 (m, 12H, CH2), 0.11–0.99 (m, 6H, BH3).
13 C{ 1 H} NMR (126 MHz, CDCl3): δ 158.2 (d, 2JPC = 6, py), 142.1 (s, py), 110.2 (d, 3JPC = 3, py), 32.9 (d, 1JPC = 36, tBu{C}), 30.8 (d, 2JPC = 13, CH2), 27.7 (s, CH2), 27.52 (s, CH2), 27.47 (s, CH2), 26.9 (s, CH2), 25.5 (d, 1JPC = 31, CH2), 25.0 (d, 2JPC = 3, tBu{CH3}), 22.7 (s, CH2).
31 P{ 1 H} NMR (162 MHz, CDCl3): δ 144.1 (vbr, fwhm = 155 Hz).
HR ESI-MS (positive ion 4 kV): 532.3804, [M + Na]+ (calcd 532.3795) m/z.
Anal. Calcd for C27H55B2NO2P2 (509.31 g mol−1): C, 63.67; H, 10.89; N, 2.75; Found: C, 63.66; H, 11.03; N, 2.74.
1 H NMR (500 MHz, C6D6): δ 7.08 (t, 3JHH = 7.7, 1H, py), 6.90 (d, 3JHH = 7.7, 2H, py), 3.04 (d, 2JHH = 13.0, 2H, pyC2), 2.87 (dd, 2JHH = 13.0, 2JPH = 2.9, 2H, pyC2), 1.50–1.57 (m, 2H, CH2), 1.38–1.49 (m, 8H, CH2), 1.27–1.38 (m, 18H, CH2), 1.03 (d, 3JPH = 11, 18H, tBu).
13 C{ 1 H} NMR (126 MHz, C6D6): δ 160.4 (d, 2JPC = 8, py), 136.0 (s, py), 120.5 (dd, 3JPC = 6, 5JPC = 2, py), 35.5 (d, 1JPC = 24, pyH2), 30.8 (d, 1JPC = 12, tBu{C}), 28.5 (s, CH2), 28.2 (s, CH2), 28.1 (s, CH2), 28.0 (s, CH2), 27.6 (d, 2JPC = 14, tBu{CH3}), 27.3 (s, CH2), 27.1 (s, CH2), 24.4 (d, 1JPC = 20, CH2).
31 P{ 1 H} NMR (121 MHz, C6D6): δ 4.5 (s).
LR ESI-MS (positive ion, 4 kV): 532.5, [M]+ (calcd 532.3) m/z.
31 P{ 1 H} NMR (162 MHz, THF:HNEt2, selected data): δ 146.5 (s).
1 H NMR (500 MHz, CD2Cl2): δ 7.95 (t, 3JHH = 7.9, 1H, py), 7.70–7.76 (m, 8H, ArF), 7.59–7.68 (m, 4H, 2 × py + 2 × biph), 7.56 (br, 4H, ArF), 7.48 (d, 3JHH = 7.6, 1H, biph), 7.10–7.26 (m, 2H, biph), 6.98 (t, 3JHH = 7.3, 1H, biph), 6.50 (t, 3JHH = 7.6, 1H, biph), 5.63 (d, 3JHH = 8.2, 1H, biph), 3.85–4.04 (m, 2H, pyC2), 3.51–3.76 (m, 2H, pyC2), 2.66–2.78 (m, 1H, CH2), 2.05–2.24 (m, 1H, CH2), 1.74–1.83 (m, 1H, CH2), 1.40–1.70 (m, 10H, CH2), 1.18–1.39 (m, 7H, CH2), 1.16 (d, 3JPH = 13.3, 9H, tBu), 0.96–1.09 (m, 4H, CH2), 0.66–0.87 (m, 3H, CH2), 0.51 (d, 3JPH = 15, 9H, tBu), 0.19–0.35 (m, 1H, CH2).
13 C{ 1 H} NMR (126 MHz, CD2Cl2): δ 162.5 (app t, JPC = 5, py), 162.3 (q, 1JCB = 50, ArF), 162.1 (app t, JPC = 3, py), 161.7 (obscured, biph), 152.3 (d app t, 1JRhC = 44, 2JPC = 7, biph), 151.2 (s, biph), 148.9 (s, biph), 140.5 (s, py), 135.4 (s, ArF), 133.9 (s, biph), 129.6 (s, biph), 129.4 (qq, 2JFC = 32, 3JCB = 3, ArF), 128.5 (s, biph), 126.7 (s, biph), 125.2 (q, 1JFC = 272, ArF), 125.1 (s, biph), 124.1 (s, biph), 123.5 (d, 3JPC = 8, py), 123.4 (d, 3JPC = 10, py), 122.4 (s, biph), 121.9 (s, biph), 118.0 (sept, 3JFC = 4, ArF), 40.1 (d, 1JPC = 23, pyH2), 38.7 (d, 1JPC = 19, pyH2), 34.4 (dd, 1JPC = 16, 3JPC = 5, tBu{C}), 33.0 (ddd, 1JPC = 20, 3JPC = 5, 2JRhC = 2, tBu{C}), 32.0 (d, 2JPC = 14, CH2), 30.3 (s, CH2), 29.7 (s, CH2), 29.54 (s, CH2), 29.51 (s, CH2), 29.43 (d, 2JPC = 4, tBu{CH3}), 29.37 (s, CH2), 29.3 (s, CH2), 28.0 (s, CH2), 27.3 (s, CH2), 26.2 (d, 1JPC = 21, PCH2), 25.7 (s, tBu{CH3}), 25.6 (obscured, CH2), 24.9 (s, CH2), 24.6 (s, CH2), 21.0 (d app t, 1JPC = 16, J = 2, PCH2).
31 P{ 1 H} NMR (162 MHz, CD2Cl2): δ 43.1 (dd, 2JPP = 339, 1JRhP = 110, 1P), 38.4 (dd, 2JPP = 339, 1JRhP = 113, 1P).
HR ESI-MS (positive ion, 4 kV): 732.3329, [M]+ (calcd 732.3329) m/z.
Anal. Calcd for C73H73BF24NP2Rh (1596.02 g mol−1): C, 54.94; H, 4.61; N, 0.88; Found: C, 54.89; H, 4.80; N, 0.86.
1 H NMR (500 MHz, CD2Cl2): δ 8.11 (t, 3JHH = 8.2, 1H, py), 7.70–7.76 (m, 8H, ArF), 7.65 (d, 3JHH = 7.3, 1H, biph), 7.56 (br, 4H, ArF), 7.54 (obscured, 1H, biph), 7.47 (d, 3JHH = 7.2, 1H, biph), 7.16–7.21 (m, 2H, biph), 7.15 (d, 3JHH = 8.2, 1H, py), 7.10 (d, 3JHH = 8.2, 1H, py), 7.06 (t, 3JHH = 7.4, 1H, biph), 6.56 (t, 3JHH = 7.7, 1H, biph), 5.32 (d, 3JHH = 8.8, 1H, biph), 2.64–2.86 (m, 2H, CH2), 1.85–2.08 (m, 3H, CH2), 1.60–1.78 (m, 4H, CH2), 1.29 (d, 3JPH = 14.6, 9H, tBu), 1.00–1.58 (m, 13H, CH2), 0.84–0.96 (m, 1H, CH2), 0.65–0.83 (m, 3H, CH2), 0.62 (d, 3JPH = 17.4, 9H, tBu), 0.37–0.48 (m, 2H, CH2).
13 C{ 1 H} NMR (126 MHz, CD2Cl2): δ 162.7 (dd, 2JPC = 6, 4JPC = 2, py), 162.3 (q, 1JCB = 50, ArF), 161.5 (dd, 2JPC = 6, 4JPC = 2, py), 159.1 (ddd, 1JRhC = 32, 2JPC = 11, 2JPC = 5, biph), 151.9 (ddd, 1JRhC = 43, 2JPC = 9, 2JPC = 7, biph), 151.2 (s, biph), 149.1 (br, biph), 147.2 (s, py), 135.4 (s, ArF), 133.9 (s, biph), 129.4 (qq, 2JFC = 32, 3JCB = 3, ArF), 129.35 (s, biph), 128.3 (s, biph), 127.6 (biph), 126.2 (s, biph), 125.2 (q, 1JFC = 272, ArF), 125.0 (s, biph), 123.3 (s, biph), 122.5 (s, biph), 118.0 (sept, 3JFC = 4, ArF), 106.1 (d, 3JPC = 4, py), 105.7 (d, 3JPC = 5, py), 41.6 (dd, 1JPC = 9, 2JRhC = 7, tBu{C}), 38.1 (ddd, 1JPC = 17.8, 3JPC = 7, 2JPC = 3, tBu{C}), 35.8 (d, JPC = 11, CH2), 31.3 (s, CH2), 30.9 (dd, 1JPC = 15, 3JPC = 3, PCH2), 30.7 (s, CH2), 30.5 (s, CH2), 30.3 (s, CH2), 30.0 (s, CH2), 29.2 (s, CH2), 28.6 (s, CH2), 28.2 (s, CH2), 28.0 (d, JPC = 7, CH2), 27.5 (d, 2JPC = 5, tBu{CH3}), 25.0 (d app t, 1JPC = 14, J = 3, PCH2), 24.4 (d, 2JPC = 4, tBu{CH3}), 24.2 (d, JPC = 4, CH2), 23.7 (s, CH2).
31 P{ 1 H} NMR (162 MHz, CD2Cl2): δ 191.1 (dd, 2JPP = 373, 1JRhP = 110, 1P), 182.9 (dd, 2JPP = 373, 1JRhP = 121, 1P).
HR ESI-MS (positive ion, 4 kV): 736.2909, [M]+ (calcd 736.2914) m/z.
Anal. Calcd for C71H69BF24NO2P2Rh (1599.96 g mol−1): C, 53.30; H, 4.35; N, 0.88; Found: C, 53.12; H, 4.48; N, 0.86.
1 H NMR (500 MHz, DFB, H2): δ 8.09–8.15 (m, 8H, ArF), 7.54 (t, 3JHH = 7.8, 1H, py), 7.49 (br, 4H, ArF), 7.22 (obscured 2H, py), 3.46 (dvt, 2JHH = 17.7, JPH = 4, 2H, pyC2), 3.23 (dvt, 2JHH = 17.7, JPH = 4, 2H, pyC2), 1.51–1.71 (m, 10H, CH2), 1.14–1.41 (m, 18H, CH2), 0.94 (vt, JPH = 8, 18H, tBu), −10.43 (vbr, fwhm ∼800 Hz, 2H, RhH).
13 C{ 1 H} NMR (126 MHz, DFB, H2): δ 164.1 (vt, JPC = 5, py), 162.3 (q, 1JCB = 50, ArF), 140.1 (s, py), 135.4 (s, ArF), 129.6 (qq, 2JFC = 32, 3JCB = 3, ArF), 125.2 (q, 1JFC = 272, ArF), 121.1 (vt, JPC = 5, py), 117.6 (sept, 3JFC = 4, ArF), 37.9 (vt, JPC = 9, pyH2), 32.0 (vt, JPC = 12, tBu{C}), 28.7 (vt, JPC = 4, CH2), 28.5 (s, CH2), 28.4 (s, CH2), 28.0 (s, CH2), 27.0 (s, CH2), 26.4 (vt, JPC = 3, tBu{CH3}), 24.7 (vt, JPC = 3, CH2), 20.8 (vtd, JPC = 12, 2JRhC = 2, PCH2).
31 P{ 1 H} NMR (162 MHz, DFB, H2): δ 65.9 (d, 1JRhP = 120).
1 H NMR (600 MHz, DFB, selected data under argon): δ −10.76 (vbr, fwhm = 60 Hz, T1 = 45 ± 11 ms, 2H, RhH).
1 H NMR (500 MHz, DFB, H2): δ 8.09–8.15 (m, 8H, ArF), 7.63 (t, 3JHH = 8.2, 1H, py), 7.49 (br, 4H, ArF), 6.63 (obscured 2H, py), 2.03–2.18 (m, 4H, CH2), 1.53–1.78 (m, 6H, CH2), 1.15–1.41 (m, 18H, CH2), 1.11 (vt, JPH = 8, 18H, tBu), −8.65 (vbr, fwhm = 100 Hz, 2H, RhH).
13 C{ 1 H} NMR (126 MHz, DFB, H2): δ 163.5 (br, py), 162.3 (q, 1JCB = 50, ArF), 145.9 (s, py), 135.4 (s, ArF), 129.6 (qq, 2JFC = 32, 3JCB = 3, ArF), 125.2 (q, 1JFC = 272, ArF), 117.6 (sept, 3JFC = 4, ArF), 103.3 (vt, JPC = 3, py), 37.6 (vt, JPC = 12, tBu{C}), 29.0 (br, CH2), 28.5 (s, CH2), 28.1 (s, CH2), 28.0 (s, CH2), 27.5 (vt, JPC = 9, PCH2), 27.3 (s, CH2), 24.7 (vt, JPC = 4, tBu{CH3}), 23.9 (vt, JPC = 3, CH2).
31 P{ 1 H} NMR (162 MHz, DFB, H2): δ 211.5 (d, 1JRhP = 127).
1 H NMR (600 MHz, DFB, selected data under argon): δ −8.51 (vbr d, fwhm = 60 Hz, 1JRhH = 21, T1 = 48 ± 6 ms, 2H, RhH).
1 H NMR (500 MHz, DFB, C2H4): δ 8.09–8.15 (m, 8H, ArF), 7.51 (t, 3JHH = 8.0, 1H, py), 7.49 (br, 4H, ArF), 7.15 (obscured, 2H, py), 3.70 (br, 2H, C2H4), 3.52 (br, 2H, C2H4), 3.31 (dvt, 2JHH = 17.3, JPH = 4, 2H, pyC2), 3.22 (dvt, 2JHH = 17.4, JPH = 4, 2H, pyC2), 1.72–1.93 (m, 4H, CH2), 1.55–1.67 (m, 2H, CH2), 1.39–1.50 (m, 2H, CH2), 1.07–1.37 (m, 20H, CH2), 0.83 (vt, JPH = 7, 18H, tBu).
13 C{ 1 H} NMR (126 MHz, DFB, C2H4): δ 162.9 (vt, JPH = 5, py), 162.3 (q, 1JCB = 50, ArF), 140.1 (s, py), 135.1 (s, ArF), 129.6 (qq, 2JFC = 32, 3JCB = 3, ArF), 125.2 (q, 1JFC = 272, ArF), 120.7 (vt, JPC = 5, py), 117.6 (sept, 3JFC = 4, ArF), 55.0 (d, 1JRhC = 12, C2H4), 37.5 (vt, JPC = 8, pyH2), 32.8 (vt, JPC = 10, tBu{C}), 29.5 (vt, JPC = 4, CH2), 29.3 (s, CH2), 28.7 (s, CH2), 28.2 (s, CH2), 27.9 (s, CH2), 26.6 (vt, JPC = 3, tBu{CH3}), 24.1 (s, CH2), 21.9 (vt, JPC = 10, PCH2).
31 P{ 1 H} NMR (162 MHz, DFB, C2H4): δ 53.0 (d, 1JRhP = 125).
1 H NMR (500 MHz, DFB, C2H4): δ 8.09–8.15 (m, 8H, ArF), 7.61 (t, 3JHH = 8.1, 1H, py), 7.49 (br, 4H, ArF), 6.59 (obscured 2H, py), 3.95 (br, 2H, C2H4), 3.70 (br, 2H, C2H4), 2.19–2.29 (m, 2H, CH2), 2.05–2.16 (m, 2H, CH2), 1.74–1.86 (m, 2H, CH2), 1.46–1.60 (m, 4H, CH2), 1.02–1.45 (m, 18H, CH2), 0.96 (vt, JPH = 8, 18H, tBu).
13 C{ 1 H} NMR (126 MHz, DFB, C2H4): δ 162.8 (vt, JPC = 3, py), 162.3 (q, 1JCB = 50, ArF), 145.3 (s, py), 135.1 (s, ArF), 129.6 (qq, 2JFC = 32, 3JCB = 3, ArF), 125.2 (q, 1JFC = 272, ArF), 117.6 (sept, 3JFC = 4, ArF), 103.2 (vt, JPC = 3, py), 59.5 (d, 1JRhC = 11, C2H4), 39.1 (vt, JPC = 10, tBu{C}), 30.0 (vt, JPC = 2, CH2), 28.7 (s, CH2), 28.6 (s, CH2), 28.5 (s, CH2), 28.4 (s, CH2), 27.3 (vtd, JPC = 8, 2JRhC = 2, PCH2), 24.9 (vt, JPC = 3, tBu{CH3}), 23.7 (s, CH2).
31 P{ 1 H} NMR (162 MHz, DFB, C2H4): δ 199.1 (d, 1JRhP = 129).
1 H NMR (500 MHz, CD2Cl2): δ 7.79 (t, 3JHH = 7.8, 1H, py), 7.70–7.76 (m, 8H, ArF), 7.56 (br, 4H, ArF), 7.42 (d, 3JHH = 7.9, 2H, py), 3.70 (dvt, 2JHH = 17.5, JPH = 4, 2H, pyC2), 3.56 (dvt, 2JHH = 17.5, JPH = 4, 2H, pyC2), 2.02–2.09 (m, 4H, CH2), 1.78–1.98 (m, 4H, CH2), 1.63–1.75 (m, 2H, CH2), 1.49–1.63 (m, 2H, CH2), 1.21–1.49 (m, 16H, CH2), 1.13 (vt, JPH = 8, 18H, tBu).
13 C{ 1 H} NMR (126 MHz, CD2Cl2): δ 194.7 (dt, 1JRhC = 70, 2JPC = 13, CO), 163.8 (vtd, JPC = 5, 2JRhC = 1, py), 162.3 (q, 1JCB = 50, ArF), 141.6 (s, py), 135.4 (s, ArF), 129.4 (qq, 2JFC = 32, 3JCB = 3, ArF), 125.2 (q, 1JFC = 272, ArF), 122.1 (vt, JPC = 5, py), 118.0 (sept, 3JFC = 4, ArF), 38.7 (vt, JPC = 9, pyH2), 33.9 (vt, JPC = 12, tBu{C}), 30.3 (vt, JPC = 4, CH2), 29.3 (s, CH2), 28.94 (s, CH2), 28.88 (s, CH2) 28.4 (s, CH2), 27.8 (vt, JPC = 3, tBu{CH3}), 26.2 (s, CH2), 23.2 (vtd, JPC = 12, 2JRhC = 3, PCH2).
31 P{ 1 H} NMR (162 MHz, CD2Cl2): δ 67.5 (d, 1JRhP = 122).
IR (CH2Cl2): ν(CO) 1997 cm−1.
HR ESI-MS (positive ion, 4 kV): 608.2653, [M]+ (calcd 608.2652) m/z.
Anal. Calcd for C62H65BF24NOP2Rh (1471.83 g mol−1): C, 50.60; H, 4.45; N, 0.95 Found: C, 50.53; H, 4.47; N, 1.08.
1 H NMR (500 MHz, CD2Cl2): δ 7.91 (t, 3JHH = 8.2, 1H, py), 7.70–7.76 (m, 8H, ArF), 7.56 (br, 4H, ArF), 6.86 (d, 3JHH = 8.2, 2H, py), 2.40–2.60 (m, 4H, CH2), 1.76–1.98 (m, 6H, CH2), 1.52–1.65 (m, 3H, CH2), 1.11–1.48 (m, 15H, CH2), 1.29 (vt, JPH = 8, 18H, tBu).
13 C{ 1 H} NMR (126 MHz, CD2Cl2): δ 193.2 (dt, 1JRhC = 71, 2JPC = 13, CO), 163.1 (vt, JPC = 3, py), 162.3 (q, 1JCB = 50, ArF), 147.7 (s, py), 135.4 (s, ArF), 129.5 (qq, 2JFC = 32, 3JCB = 3, ArF), 125.2 (q, 1JFC = 272, ArF), 118.0 (sept, 3JFC = 4, ArF), 104.5 (vt, JPC = 3, py), 39.9 (vtd, JPC = 11, 2JRhC = 2, tBu{C}), 30.9 (vt, JPC = 2, CH2), 29.5 (vtd, JPC = 9, 2JRhC = 3, PCH2), 29.3 (s, CH2), 29.1 (s, 2 × CH2), 28.8 (s, CH2), 26.1 (vt, JPC = 4, tBu{CH3}), 25.1 (vt, JPC = 2, CH2).
31 P{ 1 H} NMR (162 MHz, CD2Cl2): δ 210.8 (d, 1JRhP = 128).
IR (CH2Cl2): ν(CO) 2020 cm−1.
HR ESI-MS (positive ion, 4 kV): 612.2228, [M]+ (calcd 612.2237) m/z.
Anal. Calcd for C60H61BF24NO3P2Rh (1475.78 g mol−1): C, 48.83; H, 4.17; N, 0.95 Found: C, 48.91; H, 4.26; N, 1.02.
Footnote |
† Electronic supplementary information (ESI) available: NMR, IR and ESI-MS spectra of new compounds, and selected reactions (PDF). Primary NMR data (MNOVA). CCDC 1966918–1966922. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c9dt04474d |
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