MUTHUKUMARAN NIRMALA and PERIASAMY VISWANATHAMURTHI*

SUPPORTING INFORMATION

Design and synthesis of ruthenium(II) OCO pincer type NHC complexes and their catalytic role towards the synthesis of amides

Department of Chemistry, Periyar University, Salem 636 011, Tamil Nadu, India

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*For correspondence

Table of contents Page No.

Spectra of ligand and complexes……………………………..………….…………….3
Representative 1H NMR spectra for complexes……....……………….………….3
Representative13C NMR spectra for complexes……....…………………………6
Representative31P NMR spectra for complexes……….…………………………8
RepresentativeESI-mass spectra for ligand and complexes….…………………10

Catalysis
Materials and methods…………………………………….…….………………...13
General experimental procedure for amidation reactions…..…………….…….13
Characterization data of amide compounds……………………………..………14
Selected 1H NMR spectra for coupling products ……………….…………....23-26
Selected 13C NMR spectra for coupling products …………….…..…….…....27-30

Figure S1.1H NMR spectrum for [Ru-NHC] complex 1

Figure S2.1H NMR spectrum for [Ru-NHC] complex 2

Figure S3.1H NMR spectrum for [Ru-NHC] complex 3

Figure S4.13C NMR spectrum for [Ru-NHC] complex 1

Figure S5.13C NMR spectrum for [Ru-NHC] complex 2

Figure S6: 31P NMR spectrum for [Ru-NHC] complex 1

Figure S7: 31P NMR spectrum for [Ru-NHC] complex 3

Figure S8: Mass spectrum for bis-phenolate- N-heterocyclic carbene ligand (HL1)

Figure S9: Mass spectrum for [Ru-NHC] complex 1

Figure S10: Mass spectrum for [Ru-NHC] complex 3

Catalysis:

2.1 Materials and Methods:

Thin layer chromatography was carried out on aluminium or plastic backed silica plates, purchased from Aldrich. The plates were visualized under UV (254 nm) light. During compound separation, column chromatography was carried out using (200-400 mesh) silica gel purchased from Merck. Organic layers were routinely dried with anhydrous MgSO4 and concentrated using a Buchi rotary evaporator.

1H NMR chemical shifts are reported in ppm relative to tetramethylsilane (TMS) with the solvent resonance employed as the internal standard (CDCl3, 7.25 ppm; DMSO-d6, 2.50 ppm). Data are reported as follows: chemical shift multiplicity (s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet), coupling constant (Hz) and integration. 13C chemical shifts are reported (δ) from tetramethylsilane (TMS) with solvent resonance as the internal standard (CDCl3, δ 77.0 ppm, DMSO-d6, δ 39.5 ppm).Product yields refer to isolated yields after column chromatography.

2.2 General Experimental Procedure:

1 mmol alcohol, 1.2 mmol amine, 5 mol % NaH and 1 mol % of [Ru-NHC] catalyst (1-3) were introduced successively in Schlenk tube and the mixture was heated at 100 ⁰C in toluene under an argon atmosphere for 8 h. The reaction mixture was cooled to room temperature and the solvent was removed under vacuum and the residue was purified by silica gel (100-200 mesh) column chromatography to afford the amide. The resulting amides were identified by comparison of the 1H & 13C NMR data with those previously reported.

2.3 [Ru-NHC] catalyzed amide synthesis from alcohols and primary amines characterization data

N-Benzylbenzamide (1)

Following the general procedure, benzylalcohol (1 mmol) was used as the alcoholspecies and benzylamine (1.2 mmol) as the amine species. The title compound was recovered as a white solid (86-92%), after column chromatography eluting with 6:4, hexane: ethylacetate. TON: 92/86/89.1H NMR (300.13 MHz, CDCl3) δ (ppm) = 7.52-7.96 (m, 2H), 7.19-7.46 (m, 8H), 6.61 (br s, 1H, NH), 4.59 (d, J = 8.9 Hz, 2H). 13C NMR (75.47 MHz, CDCl3) δ(ppm) = 169.1, 138.2, 135.2, 128.7,128.5, 127.6,126.8, 43.8.

N-(4-methylbenzyl)benzamide (2)

Following the general procedure, benzylalcohol (1 mmol) was used as the alcohol species and 4-methyl benzylamine (1.2 mmol) as the amine species. The title compound was recovered as a white solid (79-88%), after column chromatography eluting with 6:4, hexane: ethylacetate. TON: 88/79/84.1H NMR (300.13 MHz, CDCl3) δ 7.47-7.53 (m, 7H), 7.25-7.28 (d, J = 7.2 Hz, 2H), 5.91 (br s, 1H, NH), 4.52 (d, J = 5.5 Hz, 2H), 2.28 (s, 3H). 13C NMR (75.47 MHz, CDCl3) δ 166.4, 153.3, 139.9, 138.3, 137.4, 136.2, 131.2, 127.1, 44.5, 21.2.

N-Cyclohexylbenzamide (3)

Following the general procedure, benzylalcohol (1 mmol) was used as the alcohol species and cyclohexylamine (1.2 mmol) as the amine species. The title compound was recovered as a white solid (78-86 %), after column chromatography eluting with 6:4, hexane: ethylacetate. TON: 86/78/83. 1H NMR (300.13 MHz, CDCl3) δ (ppm) = 7.68 (s, 1H), 7.52-7.58 (m, 1H), 7.12-7.36 (m, 2H), 6.09 (br s, 1H, NH), 2.98-3.16 (m, 1H), 1.95-2.08 (m, 2H), 1.57-1.79 (m, 4H), 1.42-1.48 (m, 2H), 1.12-1.32 (m, 2H). 13C NMR (75.47 MHz, CDCl3) δ (ppm) = 168.4, 139.2, 132.4, 129.6, 128.7, 126.8, 124.3, 49.2, 25.6, 24.8.

N-phenylbenzamide (4)

Following the general procedure, benzylalcohol (1 mmol) was used as the alcohol species and aniline (1.2 mmol) as the amine species. The title compound was recovered as a white solid (68-71 %), after column chromatography eluting with 6:4, hexane: ethylacetate. TON: 76/68/711H NMR (300.13 MHz, CDCl3): δ 7.68-7.51 (m, 4H, ArH), 7.24-7.19 (m, 4H, ArH), 6.81-6.74 (m, 2H, ArH), 5.58 (br s, 1H, NH). 13C NMR (75.47 MHz, CDCl3): δ 142.8, 131.9, 130.4, 129.8, 129.3, 129.1.

N-benzyl-4-methylbenzamide (5)

Following the general procedure, p-methyl benzylalcohol (1 mmol) was used as the alcohol species and benzylamine (1.2 mmol) as the amine species. The title compound was recovered as a white solid (73-80 %), after column chromatography eluting with 6:4, hexane: ethylacetate. TON: 80/73/78. 1H NMR (300.13 MHz, CDCl3) δ (ppm) = 7.58 (d, J= 8.2 Hz, 2H), 7.28-7.21 (m, 4H), 7.18- 7.08 (m, 1H), 7.07-7.01 (m, 2H), 6.39 (brs, 1H), 4.47 (d, J = 6 Hz, 2H), 2.31 (s, 3H).13C NMR (75.47 MHz, CDCl3) δ (ppm) = 166.8, 141.7, 137.8, 131.2, 128.7, 127.6, 128.4, 126.9, 127.3, 44.4, 21.2.

N-methyl-(4-methylbenzyl)-benzamide (6)

Following the general procedure, p-methyl benzylalcohol (1 mmol) was used as the alcohol species and 4-methyl benzylamine (1.2 mmol) as the amine species. The title compound was recovered as a white solid (83-94 %), after column chromatography eluting with 6:4, hexane: ethyl acetate. TON: 94/83/89.1H NMR (300.13 MHz, CDCl3) δ (ppm) = 7.51 (d, J= 8.1 Hz, 2H), 7.32-7.28 (m, 4H), 7.21-7.14 (m, 2H), 6.42 (brs, 1H), 4.39 (d, J = 6.2 Hz, 2H), 2.31 (s, 3H), 2.22 (s, 3H). 13C NMR (75.47 MHz, CDCl3) δ (ppm) = 169.1, 142.6, 138.1, 131.6, 129.2, 128.4, 125.7, 127.3, 44.2, 22.8, 21.2.

N-Cyclohexyl-4-methylbenzamide (7)

Following the general procedure, p-methyl benzylalcohol (1 mmol) was used as the alcohol species and cyclohexylamine (1.2 mmol) as the amine species. The title compound was recovered as a white solid (79-89 %), after column chromatography eluting with 6:4, hexane: ethyl acetate. TON: 89/79/81.1H NMR (300.13 MHz, CDCl3) δ (ppm) = 7.71 (s, 1H), 7.18-7.32 (m, 2H), 6.17 (br s, 1H, NH), 2.94-3.18 (m, 1H), 2.34 (s, 3H), 1.90-2.19 (m, 2H), 1.52-1.76 (m, 4H), 1.43-1.45 (m, 2H), 1.08-1.28 (m, 2H). 13C NMR (75.47 MHz, CDCl3) δ (ppm) = 169.3, 138.7, 133.6, 128.3, 128.4, 125.9, 123.9, 49.4, 25.3, 24.4, 21.7.

N-phenyl-4-methylbenzamide (8)

Following the general procedure, p-methyl benzylalcohol (1 mmol) was used as the alcohol species and aniline (1.2 mmol) as the amine species. The title compound was recovered as a white solid (68-76 %), after column chromatography eluting with 6:4, hexane: ethyl acetate. TON:76/68/71. 1H NMR (300.13 MHz, CDCl3) δ (ppm) = 7.73 (d, J= 8.3 Hz, 2H), 7.36-7.31 (m, 4H), 7.28- 7.17 (m, 1H), 7.14-7.09 (m, 2H), 6.42 (brs, 1H), 2.37 (s, 3H). 13C NMR (75.47 MHz, CDCl3) δ (ppm) = 168.8, 139.4, 135.4, 130.2, 127.3, 125.2, 124.5, 123.8, 122.3,21.7.

N-benzyl-4-methoxybenzamide (9)

Following the general procedure, p-methoxy benzylalcohol (1 mmol) was used as the alcohol species and benzylamine (1.2 mmol) as the amine species. The title compound was recovered as a white solid (81-96 %), after column chromatography eluting with 6:4, hexane: ethyl acetate. TON: 96/81/87. 1H NMR (300.13 MHz, CDCl3) δ (ppm) =7.72 (d, J = 8.3 Hz, 2H), 7.31-7.27 (m, 4H), 7.26-7.21 (m, 1H), 6.86 (d, J = 8.3 Hz, 2H), 6.39 (bs, 1H), 4.62 (d, J = 6.1 Hz, 2H), 3.87 (s, 3H).13C NMR (75.47 MHz, CDCl3) δ (ppm) = 168.2, 163.7, 138.2, 127.6, 128.4, 127.3, 126.4, 114.3, 55.2, 44.7.

N-methyl-(4-methoxybenzyl)-benzamide (10)

Following the general procedure, p-methoxy benzylalcohol (1 mmol) was used as the alcohol species and p-methyl benzylamine (1.2 mmol) as the amine species. The title compound was recovered as a white solid (79-83 %), after column chromatography eluting with 6:4, hexane: ethyl acetate. TON: 88/79/83.1H NMR (300.13 MHz, CDCl3) δ (ppm) = 7.54 (d, J= 8.3 Hz, 2H), 7.37-7.22 (m, 4H), 7.23-7.17 (m, 2H), 6.49 (brs, 1H), 4.32 (d, J = 6.6 Hz, 2H), 3.89 (s, 3H), 2.24 (s, 3H). 13C NMR (75.47 MHz, CDCl3) δ (ppm) = 168.3, 145.1, 139.4, 132.5, 128.7, 129.2, 124.3, 126.2, 43.1, 22.4, 21.6.

N-Cyclohexyl-4-methoxybenzamide (11)

Following the general procedure, p-methoxy benzylalcohol (1 mmol) was used as the alcohol species and cyclohexylamine (1.2 mmol) as the amine species. The title compound was recovered as a white solid (76-93 %), after column chromatography eluting with 6:4, hexane: ethyl acetate. TON: 93/76/87.1H NMR (300.13 MHz, CDCl3) δ (ppm) = 7.65 (s, 1H), 7.19-7.36 (m, 2H), 6.21 (br s, 1H, NH), 2.89-3.21 (m, 1H), 3.91 (s, 3H), 1.81-2.09 (m, 2H), 1.51-1.74 (m, 4H), 1.41-1.34 (m, 2H), 1.07-1.29 (m, 2H). 13C NMR (75.47 MHz, CDCl3) δ (ppm) = 168.4, 138.4, 133.4, 128.7, 128.2, 125.6, 123.2, 48.5, 25.2, 24.3, 21.6.

N-phenyl-4-methoxybenzamide (12)

Following the general procedure, p-methoxy benzylalcohol (1 mmol) was used as the alcohol species and aniline (1.2 mmol) as the amine species. The title compound was recovered as a white solid (64-79 %), after column chromatography eluting with 6:4, hexane: ethyl acetate. TON: 79/64/72. 1H NMR (300.13 MHz, CDCl3) δ (ppm) = 7.61 (d, J= 8.1 Hz, 2H), 7.34-7.29 (m, 4H), 7.24- 7.16 (m, 1H), 7.12-7.01 (m, 2H), 6.47 (brs, 1H), 3.79 (s, 3H). 13C NMR (75.47 MHz, CDCl3) δ (ppm) = 167.8, 138.3, 134.2, 130.1, 126.4, 125.4, 124.3, 123.7, 122.4,22.7.

N-(4-fluorobenzyl)benzamide (13)

Following the general procedure, p-fluoro benzylalcohol (1 mmol) was used as the alcohol species and benzylamine (1.2 mmol) as the amine species. The title compound was recovered as a white solid (64-79 %), after column chromatography eluting with 6:4, hexane: ethyl acetate. TON:81/69/73. . 1H NMR (300.13 MHz, CDCl3): δ 7.33-7.25 (m, 2H, ArH), 7.22-7.13 (m, 7H, ArH), 5.58 (br s, 1H, NH). 13C NMR (75.47 MHz, CDCl3): δ 158.5, 142.1, 138.4, 135.9, 130.2, 129.6, 128.8, 126.3, 123.6s.

N-hexylbenzylamide (14)

Following the general procedure, hexanol (1 mmol) was used as the alcohol species and benzylamine (1.2 mmol) as the amine species. The title compound was recovered as a white solid (61-76 %), after column chromatography eluting with 6:4, hexane: ethyl acetate. TON: 76/61/71.1H NMR (300.13 MHz, CDCl3) δ (ppm) =7.76 (d, J= 8.2 Hz, 2H), 7.45 (t, J= 7 .1Hz, 1H), 7.37 (t, J= 8.2 Hz, 2H), 6.37 (bs, 1H, NH), 3.40 (dt, J= 6.4 Hz,J=7.5 Hz, 2H ), 1.54 (quint, J= 7.4 Hz, 2H), 1.36-1.29 (m, 2H), 1.28-1.21 (m, 4H), 0.94 (t, J= 6.5 Hz, 3H).13C NMR (75.47 MHz, CDCl3) δ (ppm) = 167.5, 135.3, 131.2, 128.4, 126.4, 40.6, 31.5, 29.6, 26.4, 22.2, 14.7.

N-hexylbenzamide (15)

Following the general procedure, hexanol (1 mmol) was used as the alcohol species and aniline (1.2 mmol) as the amine species. The title compound was recovered as a white solid (59-68 %), after column chromatography eluting with 6:4, hexane: ethyl acetate. TON: 68/59/63.1H NMR (300.13 MHz, CDCl3) δ (ppm) = 7.81 (d, J= 8.2 Hz, 2H), 7.41 (t, J= 7 .1Hz, 1H), 6.32 (bs, 1H, NH), 3.43 (dt, J= 6.2 Hz, J=7.4 Hz, 2H ), 1.53 (quint, J= 7.4 Hz, 2H), 1.32-1.24 (m, 2H), 1.22-1.18 (m, 4H), 1.09 (t, J= 6.2 Hz, 3H).13C NMR (75.47 MHz, CDCl3) δ (ppm) = 169.7, 134.8, 130.5, 127.4, 127.3, 31.2, 29.8, 25.8, 22.3, 13.9.

[Ru-NHC] catalyzed amide synthesis from alcohols and secondary amines characterization data

1-Morpholine-2-phenylethanone (2)

Following the general procedure, 2-phenylethanol (1 mmol) was used as the alcohol species and morpholine (1.2 mmol) as the amine species. The title compound was recovered as a yellow solid (79-88 %), after column chromatography eluting with 6:4, hexane: ethyl acetate. TON:88/79/82. 1H NMR (300.13 MHz, CDCl3): δ 7.81-7.73 (m, 2H, ArH), 7.71-7.58 (m, 2H, ArH), 4.51 (d, J = 5.8 Hz, 2H), 3.74 (br s, 4H, 2OCH2), 2.82 (br s, 4H, 2NCH2), . 13C NMR (75.47 MHz, CDCl3): δ 149.9, 130.2, 128.5, 126.3, 120.1, 113.5, 49.2.

N-Benzoylpiperidine (3)

Following the general procedure, benzylalcohol (1 mmol) was used as the alcohol species and piperidine (1.2 mmol) as the amine species. The title compound was recovered as colourless oil (78-84 %), after column chromatography eluting with 6:4, hexane: ethyl acetate. TON: 84/78/821H NMR (300.13 MHz, CDCl3) δ (ppm) = 7.34 (s, 5H), 3.62 (bs, 2H), 3.29 (bs, 2H), 1.41 (bs, 4H), 1.38 (bs, 2H). 13C NMR (75.47 MHz, CDCl3) δ (ppm) = 169.3, 136.2, 128.4, 127.9, 127.2, 48.7, 43.4, 26.7, 25.6, 24.9.

N-Benzyl-N-methyl-2-phenyl-acetamide(4)

Following the general procedure, 2-phenylethanol (1 mmol) was used as the alcohol species and benzylmethylamine (1.2 mmol) as the amine species. The title compound was recovered as a pale yellow solid (68-76 %), after column chromatography eluting with 6:4, hexane: ethyl acetate. TON: 76/68/71. 1H NMR (300.13 MHz, CDCl3) δ (ppm) = 7.33-7.21 (m, 8H), 7.12-7.06 (m, 2H), 2.95(s, 3H), 2.84 (m, 4H). 13C NMR (75.47 MHz, CDCl3) δ (ppm) = 171.54, 171.3, 137.6, 135.3, 129.4, 129.1, 128.9, 128.3, 127.2, 126.5, 51.4, 41.4, 40.3, 35.9, 35.2.

N-Benzyl-N-methyl-benzamide (5)

Following the general procedure, benzyl alcohol (1 mmol) was used as the alcohol species and benzyl methylamine (1.2 mmol) as the amine species. The title compound was recovered as a white solid (73-81 %), after column chromatography eluting with 6:4, hexane: ethyl acetate. TON: 81/73/79. 1H NMR (300.13 MHz, CDCl3) δ (ppm) = 8.12-7.57 (m, 2H), 7.51-7.21 (m, 8H), 4.61 (d, J = 8.8 Hz, 2H), 3.01 (s, 3H). 13C NMR (75.47 MHz, CDCl3) δ (ppm) = 169.1, 138.4, 131.7, 129.4, 128.6, 127.3, 43.1, 35.2.

N-Benzyl-4-methoxy-N-methyl-benzamide (6)

Following the general procedure, p-methoxy benzylalcohol (1 mmol) was used as the alcohol species and benzyl methylamine (1.2 mmol) as the amine species. The title compound was recovered as a white solid (81-93 %), after column chromatography eluting with 6:4, hexane: ethyl acetate. TON: 93/81/89. 1H NMR (300.13 MHz, CDCl3) δ (ppm) = 7.61 (d, J = 8.7 Hz, 2H), 7.38-7.21 (m, 4H), 7.19-7.08 (m, 2H), 4.37 (d, J = 6.9 Hz, 2H), 3.88 (s, 3H), 2.92 (s, 3H). 13C NMR (75.47 MHz, CDCl3) δ (ppm) = 169.8, 142.3, 138.6, 129.1, 128.3, 124.6, 126.7, 56.7, 44.3, 22.8

N-Benzyl-4-fluoro-N-methyl-benzamide (7)

Following the general procedure, p-fluoro benzylalcohol (1 mmol) was used as the alcohol species and benzyl methylamine (1.2 mmol) as the amine species. The title compound was recovered as a white solid (78-88 %), after column chromatography eluting with 6:4, hexane: ethyl acetate. TON: 88/78/81. 1H NMR (300.13 MHz, CDCl3) δ (ppm) = 7.82 (d, J = 8.8 Hz, 2H), 7.74 (t, J = 7.7 Hz, 1H), 7.38 (m, 1H), 7.27-6.81 (m, 5H), 4.37 (d, J = 6.8 Hz, 2H), 2.87 (s, 3H). 13C NMR (75.47 MHz, CDCl3) δ (ppm) = 167.4, 162.1, 160.3, 140.1, 138.3, 134.7, 131.2, 130.2, 127.3, 124.6, 115.7, 44.3.

Selected 1H NMR spectra for amide products

Figure S11:1H NMR spectrum of N-benzylbenzamide

Figure S12:1H NMR spectrum of N-(4-methylbenzyl)benzamide

Figure S13:1H NMR spectrum of N-phenylbenzamide

Figure S14:1H NMR spectrum of 1-Morpholine-2-phenylethanone

Selected 13C NMR spectra for amide products

Figure S15:13C NMR spectrum of N-benzylbenzamide

Figure S16:13C NMR spectrum of N-(4-methylbenzyl)benzamide

Figure S17:13C NMR spectrum of N-phenylbenzamide

Figure S18:13C NMR spectrum of 1-Morpholine-2-phenylethanone