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. 2018 Apr 25;3(4):4522-4533.
doi: 10.1021/acsomega.8b00193. eCollection 2018 Apr 30.

Synthesis, Structures, and Reactivity of Single and Double Cyclometalated Complexes Formed by Reactions of [Cp*MCl2]2 (M = Ir and Rh) with Dinaphthyl Phosphines

Shaowei Zhang  1 , Xiaodan Chu  1 , Tongyu Li  1 , Zhuo Wang  1 , Bolin Zhu  1
Affiliations

Synthesis, Structures, and Reactivity of Single and Double Cyclometalated Complexes Formed by Reactions of [Cp*MCl2]2 (M = Ir and Rh) with Dinaphthyl Phosphines

Shaowei Zhang et al. ACS Omega. .

Abstract

Reactions of two dinaphthyl phosphines with [Cp*IrCl2]2 have been carried out. In the case of di(α-naphthyl)phenylphosphine (1a), a simple P-coordinated neutral adduct 2a is obtained. However, tert-butyldi(α-naphthyl)phenylphosphine (1b) is cyclometalated to form [Cp*IrCl(P^C)] (3b). Complexes 2a and 3a undergo further cyclometalation to give the corresponding double cyclometalated complexes [Cp*Ir(C^P^C)] (4a,b) upon heating. In the presence of sodium acetate, reactions of 1a,b with [Cp*IrCl2]2 directly afford the final double cyclometalated complexes (4a,b). In the absence of acetate, [Cp*RhCl2]2 shows no reaction with 1a,b, whereas with acetate the reactions form the corresponding single cyclometalated complexes [Cp*RhCl(P^C)] (5a,b), which react with t BuOK to form the corresponding rhodium hydride complexes (6a,b). Treatment of 4a with CuCl2 or I2 leads to opening of two Ir-C σ bonds to yield the corresponding P-coordinated iridium dihalide (7 or 8) by means of an intramolecular C-C coupling reaction. A new chiral phosphine (11) is formed by the ligand-exchange reaction of 8 with PMe3. Reactions of the single cycloiridated complex 3b with terminal aromatic alkynes result in the corresponding five- and six-membered doubly cycloiridated complex 12 and/or η2-alkene coordinated complexes 13-15; the latter discloses that the electronic effect of terminal alkynes affects the regioselectivity. While the single cyclorhodated complex 5b reacts with terminal aromatic alkynes to form the corresponding six-membered cyclometalated complexes 16a-c by vinylidene rearrangement/1,1-insertion. Plausible pathways for formation of insertion products 13-16 were proposed. Molecular structures of twelve new complexes were determined by X-ray diffraction.

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Conflict of interest statement

The authors declare no competing financial interest.

Figures

Scheme 1
Scheme 1. Reaction of [Cp*IrCl2]2 with Di(α-naphthyl)phenylphosphine (1a) or tert-Butyldi(α-naphthyl)phenylphosphine (1b)
Figure 1
Figure 1
Thermal ellipsoid drawing of 2a showing the labeling scheme and 50% probability ellipsoids; hydrogens are omitted for clarity. Selected bond lengths [Å] and angles [°] are Ir(1)–P(1) 2.349(3), Ir(1)–Cl(1) 2.417(3), Ir(1)–Cl(2) 2.407(3), Ir(1)–Cp(centroid) 1.822, ∠Cl(1)–Ir(1)–Cl(2) 85.86(9), ∠Cl(1)–Ir(1)–P(1) 92.55(9), and ∠Cl(2)–Ir(1)–P(1) 89.53(9).
Figure 2
Figure 2
Thermal ellipsoid drawing of 4a showing the labeling scheme and 50% probability ellipsoids; hydrogens are omitted for clarity. Selected bond lengths [Å] and angles [°] are Ir(1)–P(1) 2.2232(11), Ir(1)–C(11) 2.269(4), Ir(1)–C(21) 2.281(5), Ir(1)–Cp(centroid) 1.911, ∠C(11)–Ir(1)–C(21) 84.68(18), ∠C(11)–Ir(1)–P(1) 82.36(13), ∠C(21)–Ir(1)–P(1) 80.93(12).
Scheme 2
Scheme 2. Reactions of [Cp*IrCl2]2 with 1a,b in the Presence of NaOAc
Scheme 3
Scheme 3. Reactions of [Cp*RhCl2]2 with 1a,b
Scheme 4
Scheme 4. Reaction of 4a with CuCl2
Scheme 5
Scheme 5. Plausible Pathway for Formation of 7
Figure 3
Figure 3
Thermal ellipsoid drawing of 7 showing the labeling scheme and 50% probability ellipsoids; hydrogens are omitted for clarity. Selected bond lengths [Å] and angles [°] are Ir(1)–P(1) 2.3159(12), Ir(1)–Cl(1) 2.4164(11), Ir(1)–Cl(2) 2.4119(10), C(19)–C(21) 1.494(6), Ir(1)–Cp(centroid) 1.825, ∠C(11)–P(1)–C(23) 113.0(2), ∠C(11)–P(1)–C(31) 100.05(19), and ∠C(23)–P(1)–C(31) 98.95(19).
Scheme 6
Scheme 6. Reaction of 4a with I2
Figure 4
Figure 4
Thermal ellipsoid drawing of 11 showing the labeling scheme and 50% probability ellipsoids; hydrogens are omitted for clarity. Selected bond lengths [Å] and angles [°] are P(1)–C(1) 1.813(2), P(1)–C(13) 1.817(2), P(1)–C(21) 1.841(2), C(9)–C(11) 1.516(3), ∠C(1)–P(1)–C(13) 107.82(11), ∠C(1)–P(1)–C(21) 101.60(10), and ∠C(13)–P(1)–C(21) 100.76(10).
Scheme 7
Scheme 7. Reaction of 8 with PMe3
Scheme 8
Scheme 8. Reaction of 3b with p-FC6H4C≡CH
Scheme 9
Scheme 9. Reaction of 3b with p-MeOC6H4C≡CH
Figure 5
Figure 5
Thermal ellipsoid drawing of 12 showing the labeling scheme and 50% probability ellipsoids; hydrogens are omitted for clarity. Selected bond lengths [Å] and angles [°] are Ir(1)–P(1) 2.2637(13), Ir(1)–C(35) 2.048(5), Ir(1)–C(38) 2.042(5), C(35)–C(36) 1.324(7), C(36)–C(37) 1.451(7), C(33)–C(35) 1.474(7), P(1)–C(25) 1.846(5), Ir(1)–Cp(centroid) 1.918, ∠P(1)–Ir(1)–C(35) 79.64(13), ∠P(1)–Ir(1)–C(38) 98.49(14), ∠C(35)–Ir(1)–C(38) 78.4(2), ∠Ir(1)–P(1)–C(25) 108.79(17), ∠Ir(1)–C(35)–C(33) 118.2(4), ∠Ir(1)–C(35)–C(36) 117.1(4), and ∠C(35)–C(36)–C(37) 115.9(5).
Figure 6
Figure 6
Thermal ellipsoid drawing of 14 showing the labeling scheme and 50% probability ellipsoids; anion and hydrogens are omitted for clarity. Selected bond lengths [Å] and angles [°] are Ir(1)–P(1) 2.286(3), Ir(1)–C(18) 2.204(12), Ir(1)–C(19) 2.208(10), Ir(1)–C(36) 2.077(12), C(18)–C(19) 1.432(16), C(19)–C(20) 1.482(18), P(1)–C(22) 1.824(13), P(1)–C(34) 1.812(11), Ir(1)–Cp(centroid) 1.922, ∠C(18)–Ir(1)–C(19) 37.9(4), ∠C(19)–Ir(1)–P(1) 82.7(3), ∠P(1)–Ir(1)–C(36) 77.6(3), ∠C(11)–C(18)–C(19) 126.9(12), ∠C(18)–C(19)–C(20) 121.7(11), ∠C(11)–C(18)–C(19)–C(20) 3.7(18), and ∠C(36)–Ir(1)–P(1)–C(34) 33.0(12).
Figure 7
Figure 7
Thermal ellipsoid drawing of 15c showing the labeling scheme and 50% probability ellipsoids; anion and hydrogens are omitted for clarity. Selected bond lengths [Å] and angles [°] are Ir(1)–P(1) 2.288(2), Ir(1)–C(11) 2.139(8), Ir(1)–C(35) 2.289(9), Ir(1)–C(42) 2.121(9), C(35)–C(42) 1.449(14), C(33)–C(35) 1.541(14), Ir(1)–Cp(centroid) 1.928, ∠C(35)–Ir(1)–C(42) 38.1(4), ∠C(35)–Ir(1)–P(1) 86.4(2), ∠P(1)–Ir(1)–C(11) 74.2(3), ∠C(42)–C(35)–C(36) 119.0(8), ∠C(42)–C(35)–C(33) 115.7(9), and ∠C(11)–Ir(1)–P(1)–C(13) 36.9(9).
Scheme 10
Scheme 10. Reaction of 3b with p-RC6H4C≡CH (R = H, MeO, or F) in the Presence of NaBArF4
Scheme 11
Scheme 11. Plausible Pathway for the Formation of 15a–c (Anion Cl– or BArF4– is Omitted for Clarity)
Scheme 12
Scheme 12. Reaction of 5b with p-RC6H4C≡CH (R = H, MeO, or F)
Figure 8
Figure 8
Thermal ellipsoid drawing of 16b showing the labeling scheme and 50% probability ellipsoids; hydrogens are omitted for clarity. Selected bond lengths [Å] and angles [°] are Rh(1)–P(1) 2.2941(11), Rh(1)–Cl(1), 2.4183(11) Rh(1)–C(21) 2.064(4), C(20)–C(21) 1.482(6), C(21)–C(22) 1.331(6), C(22)–C(23) 1.485(6), Rh(1)–Cp(centroid) 1.891, ∠Cl(1)–Rh(1)–C(21) 94.76(12), ∠C(21)–Rh(1)–P(1) 82.67(12), ∠P(1)–Rh(1)–Cl(1) 98.49(4), ∠Rh(1)–C(21)–C(20) 116.8(3), ∠Rh(1)–C(21)–C(22) 118.7(3), ∠C(20)–C(21)–C(22) 123.5(4), ∠C(21)–C(22)–C(23) 129.9(4), and ∠C(20)–C(21)–C(22)–C(23) −9.4(7).
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