Palladium(II), silver(I), and gold(I) complexes of a new class of chiral bicyclic [1,2,3]-triazolooxazine derived N-heterocyclic carbenes (NHCs): Synthesis, structure and application studies

Accessing Heteroannular Benzoxazole and Benzimidazole Scaffolds via Carbodiimides Using Azide–Isocyanide Cross-Coupling as Catalyzed by Mesoionic Singlet Palladium Carbene Complexes Derived from a Phenothiazine Moiety

“…As expected, the molecular structure of 4 (Figure 2 and Supporting Information, Table S1), as determined by the single crystal X-ray diffraction study, exhibited a nonplanar butterfly structure with the S and N heteroatoms occupying the 1,4 apical positions, while the two aromatic rings are pointed outward from the (2,3) and (5,6) positions of a boat confirmation, consistent with commonly observed conformation of a phenothiazine moiety. 42 In agreement with the d 8 35 (Supporting Information, Table S2).…”

“…Furthermore, the characteristic Pd−C carbene peak at δ ca. 139.0 ppm (Supporting Information, Figures S22−S23) in the 13 C{ 1 H} NMR spectra of ( 4) is comparable to that observed for related trans-[1-Ph-3-Me-4-Ph-1,2,3-triazol-5-ylidene]-PdI 2 (NC 5 H 5 ) (δ ca.139.8 ppm), 41 trans-[{(S)-7-CH 2 Ph-2-Me-6,7-dihydro-4H- [1,2,3]-triazolo [5,1-c] [1,4]oxazin-3-ylidene}PdI 2 (NC 5 H 5 ) (δ ca.138.5 ppm) 35 and the other structurally characterized examples known in the literature (Supporting Information, Table S2).…”

“…The Pd–C carbene bond distance of 1.981(8) Å in ( 4 ) compared well with the representative reported analogues, namely trans -[1-Ph-3-Me-4-Ph-1,2,3-triazol-5-ylidene]PdI 2 (NC 5 H 5 ) [1.971(6) Å] 41 and trans -{(S)-7-CH 2 Ph-2-Me-6,7-dihydro-4 H -[1,2,3]-triazolo[5,1- c ][1,4]oxazin-3-ylidene}PdI 2 (NC 5 H 5 ) [1.974(9) Å]. 35 ( Supporting Information, Table S2 ).…”

“…With our interest in exploring the potentials of the transition metal complexes of the heteroatom stabilized cyclic and acyclic singlet carbene ligands in homogeneous catalysis − and in biomedical applications, we study different singlet-carbene ligand classes covering the cyclic normal N-heterocyclic carbenes, abnormal mesoionic carbenes , the acyclic diaminocarbenes , and the fused-cyclic ones of the imidazole, benzimidazole, triazole, ,, oxazolidine, bioxazoline, and triazolooxazine architectures. The mesoionic (MIC) carbenes, featuring less heteroatom stabilization than the more ubiquitous normal N-heterocyclic carbenes, come with specific donors and reactivity properties but surprisingly remain less explored .…”

Syntheses and crystal structure of 4-[(pyridin-3-yl)diazenyl]morpholine and 1-[(pyridin-3-yl)diazenyl]-1,2,3,4-tetrahydroquinoline

“…The N2-N3 double-bond distance of 1.2679 (13) A ånd the N1-N2 single-bond distance of 1.3501 (12) A ˚in EMUDEX are in accordance with those reported for OFUBUO (Mukai et al, 2013), EZEXEN (Gholivand et al, 2010), FUZLUI (Pye et al, 2010). The structures of HAHQOZ (Johnson et al 2016), HUHGEZ (Isovitsch & Fronczek, 2020), IJEVUR (Gangwar et al, 2021), OPAVUX (Chin et al, 2011) and RUJQIX (Chin et al, 2009) feature similar intermolecular hydrogen-bonding interactions to those in I, resulting in supramolecular networks.…”