Synthesis and conformational features of sym N,N′,N″-triarylguanidines

Gopi, Kanniyappan; Rathi, Brijesh; Thirupathi, Natesan

doi:10.1007/s12039-010-0017-8

Cited by 17 publications

(39 citation statements)

References 48 publications

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“…1.28 Å, known for symmetrical N , N ′, N ″-triarylguanidines, [(ArNH) 2 CNAr] ( LH 2 Ar ), while C1–N2 and C1–N3 distances in 9 (1.377(4) and 1.421(4) Å) and 10 ·H 2 O (1.370(4) and 1.392(4)Å) compare well with the C–N single bond distances known for LH 2 Ar (ca. 1.38 Å) . The bond parameters around the Pd(II) atom in 9 and 10 ·H 2 O compare well with the corresponding bond parameters reported for [6,5] CNN Pd(II) pincer complexes of the type [Pd{κ 3 ( C , N , N )}(L)] (L = MeCN (five examples) and pyridine (one example)). , Thus, the dianionic nature of the guanidinate ligands in 9 and 10 ·H 2 O is evident.…”

Section: Resultssupporting

confidence: 80%

[6,5] CNN Palladium(II) Pincer Complexes Containing N-Substituted Monoanionic and Dianionic Guanidinate Ligands: Syntheses, Structural Aspects, and Their Utility in Suzuki–Miyaura Coupling Reactions

Sinha

Thirupathi

2021

Organometallics

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The reactions of guanidines [(ArNH)(ArN)CN-(H)(C(O)Py-2)] (Ar = 2-RC 6 H 4 ; R = Me (1) and CF 3 (2)) with Pd(OC(O)R′) 2 (R′ = Me, t Bu and CF 3 ) were studied with a view aimed at understanding the influence of substituent effects upon the nature of the resulting products. The reactions of 1 with Pd(OC(O)R′) 2 (R′ = Me and CF 3 ) in toluene at 65 °C afforded [Pd{κ 3 (C,N,N)}(OC(O)R′)] (R′ = Me (3) and CF 3 (4)), while the analogous reaction involving 1 and Pd(OC(O) t Bu) 2 afforded [Pd{κ 3 (C,N,N)}(μ-OC(O) t Bu)Pd{κ 3 (C,N,N)}] (5). The analogous reactions of 2 with Pd(OC(O)R′) 2 (R′ = Me, t Bu and CF 3 ) afforded [Pd{κ 3 (C,N,N)}(μ-OC(O)R′)Pd{κ 3 (C,N,N)}] (R′ = Me (6) and t Bu (7)) and [Pd{κ 3 (C,N,N)}(OC(O)CF 3 )] (8), respectively. Complexes 5−7 were treated with 2 equiv of Lewis bases, L at RT to afford [Pd{κ 3 (C,N,N)}(L)] [L = PPh 3 (9), 4-aminopyridine (10 and 11), and MeCN (12)]. The mechanisms of formation of new complexes were proposed. Complex 3 was treated with 12 in the presence of excess of NaOC(O) t Bu in CHCl 3 under reflux condition to afford a mixed Pd(II) pincer, [Pd{κ 3 (C,N,N)}(μ-OC(O) t Bu)Pd{κ 3 (C,N,N)}] (15), and this observation indirectly supports the mechanism proposed for the formation of 5−7. The mechanisms of formation of 9−12 were verified by in situ reaction involving 7 and PPh 3 (1 and 2 equiv) through 19 F NMR spectroscopy. The new compounds were fully characterized, and molecular structures of 1, 3•C 7 H 8 , 4−6, 8•C 7 H 8 , 9, and 10•H 2 O were determined by SCXRD. The CNN tridentate guanidinate ligands were present in monoanionic (3•C 7 H 8 , 4 and 8•C 7 H 8 ), mono-and dianionic (5 and 6), and dianionic (9 and 10•H 2 O) forms, and hence the structures of 5 and 6 are unprecedented. Complex 3•C 7 H 8 was used as an efficient catalyst in Suzuki−Miyaura reactions involving sterically hindered aryl bromides and aryl boronic acids.

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Section: Resultssupporting

confidence: 80%

[6,5] CNN Palladium(II) Pincer Complexes Containing N-Substituted Monoanionic and Dianionic Guanidinate Ligands: Syntheses, Structural Aspects, and Their Utility in Suzuki–Miyaura Coupling Reactions

Sinha

Thirupathi

2021

Organometallics

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“…The ρ values for new compounds listed in Table 1 are much greater than the ρ value known for the respective free guanidines. 42 The ρ value of 1.00 for [LH 3 2-anisyl ]TFA is as anticipated due to a maximum n−π conjugation, which arises because of the presence of a charge-delocalized Y-conjugated species (angle sum around CN 3 carbon, ∑C ≈ 360°). 45 The amino N atoms of the guanidine moieties are planar (∑N ≈ 360°) in all compounds, further supporting enhanced n−π conjugation in all new compounds listed in Table 1.…”

Section: Resultsmentioning

confidence: 53%

“…38,41 The nonplatinated guanidine in 1 ·1/2CH 2 Cl 2 and 3 revealed anti–anti conformation as reported for free LH 2 2-tolyl . 42…”

Section: Resultsmentioning

confidence: 99%

Critical Role of Anions in Platinum(II) Precursors upon the Structural Motifs of Six-Membered Cycloplatinated N,N′,N″-Triarylguanidines

Mishra

Thirupathi

2018

ACS Omega

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The reactions of cis -[Pt(OAc) 2 (DMSO) 2 ] with 2 equiv of sym N , N ′, N ″-triarylguanidines, [ArN=C(NHAr) 2 ], in toluene under reflux condition for 8 h afforded six-membered cycloplatinated guanidines, [Pt{κ 2 ( C , N )}(OAc){κ 1 N (ArN=C(NHAr) 2 )}] [ sym = symmetrical; Ar = 2-MeC 6 H 4 ( 1 ) and 2,4-Me 2 C 6 H 3 ( 2 )], in 82 and 84% yields, respectively. The salt metathesis reaction of 1 with 1 equiv of AgTFA in CH 2 Cl 2 at room temperature (RT) afforded [Pt{κ 2 ( C , N )}(TFA){κ 1 N (ArN=C(NHAr) 2 )}] ( 3 ) in 94% yield. The reaction of cis -[Pt(TFA) 2 (DMSO) 2 ] with 1 equiv of [ArN=C(NHAr) 2 ] in toluene under reflux condition for 8 h afforded six-membered cycloplatinated guanidines, [Pt{κ 2 ( C , N )}(TFA)(DMSO)] [Ar = 2-MeC 6 H 4 ( 4 ), 4-MeC 6 H 4 ( 5 ), 2,4-Me 2 C 6 H 3 ( 6 ), and 2-(MeO)C 6 H 4 ( 7 )], in ≥73% yields. The reaction of trans -[PtCl 2 (PhCN) 2 ] with 2 equiv of [ArN=C(NHAr) 2 ] in toluene under reflux condition for 48 h afforded trans -[PtCl 2 {ArN=C(NHAr) 2 } 2 ] [Ar = 2-MeC 6 H 4 ( 8 ) and 2,4-Me 2 C 6 H 3 ( 9 )] in 90 and 45% yields, respectively. Complexes 8 and 9 were separately refluxed in MeOH for 8 h to afford six-membered cycloplatinated guanidines, [Pt{κ 2 ( C , N )}(μ-Cl)] 2 ( 10 and 11 ), in 93 and 96% yields, respectively, with concomitant formation of the respective guanidinium salts, [(ArNH) 3 ...

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“…For the structure of the parent guanidine ligand, see: . For a series of related guanidines with varying conformational isomers, see: Gopi et al (2010). For applications of this same ligand with cobalt(II) for catalysis, see: Eichman et al (2011).…”

Section: Related Literaturementioning

confidence: 99%

Tricarbonyl[N,N′,N′′-tris(2,6-diisopropylphenyl)guanidine]molybdenum(0)

Boeré

Masuda

2011

Acta Cryst E

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In the title compound, [Mo(C37H53N3)(CO)3], the Mo atom to ring-centroid distance in the η6-coordinated tricarbonylmolybdenum group is 1.958 (1) Å. The three C O groups are pseudo-octahedrally disposed with C—Mo—C angles ranging from 80.7 (1) to 87.4 (1)°. The two uncoordinated 2,6-diisopropylphenyl-substituted benzene rings form dihedral angles of 75.96 (8) and 78.01 (9)° with the mean plane of the guanidine group. The coordinated benzene ring is in a slight sofa conformation with the N-substituted C atom and the bonded N atom dispaced by 0.090 (3) and 0.458 (4) Å, respectively, from the mean plane of the remaining ring atoms. In the crystal, despite there being two N—H donor groups, no conventional hydrogen bonds are present. This may be because of the steric effects of the bulky diisopropylphenyl groups.

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Synthesis and conformational features of sym N,N′,N″-triarylguanidines

Cited by 17 publications

References 48 publications

[6,5] CNN Palladium(II) Pincer Complexes Containing N-Substituted Monoanionic and Dianionic Guanidinate Ligands: Syntheses, Structural Aspects, and Their Utility in Suzuki–Miyaura Coupling Reactions

[6,5] CNN Palladium(II) Pincer Complexes Containing N-Substituted Monoanionic and Dianionic Guanidinate Ligands: Syntheses, Structural Aspects, and Their Utility in Suzuki–Miyaura Coupling Reactions

Critical Role of Anions in Platinum(II) Precursors upon the Structural Motifs of Six-Membered Cycloplatinated N,N′,N″-Triarylguanidines

Tricarbonyl[N,N′,N′′-tris(2,6-diisopropylphenyl)guanidine]molybdenum(0)

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