Crystal structures of tris[1-oxopyridine-2-olato(1−)]silicon(IV) chloride chloroform-d₁disolvate, tris[1-oxopyridine-2-olato(1−)]silicon(IV) chloride acetonitrile unquantified solvate, andfac-tris[1-oxopyridine-2-thiolato(1−)]silicon(IV) chloride chloroform-d₁disolvate

Abstract

The homoleptic triply-ligated cation in two silyl chloride salt solvates of 1-oxo-2-pyridinone is found to co-crystallize as a mixture of fac and mer isomers. A related silyl cation of 1-oxo-2-pyridine­thione is found as the fac isomer.

Chelation Equilibria and π-Electron Delocalization in Neutral Hypercoordinate Organosilicon Complexes of Pyrithione

“…Selected bond distances and angles are given in Table S5. Both structures exhibit pseudotetrahedral coordination spheres and form a covalent bond between silicon and the hydroxylamine oxygen, as is also observed in their 1-oxo-2-pyridinone (OPO) analogues . This bonding arrangement contrasts with most known structures of simple hydrocarbon-based OPTO derivatives, which are N -oxides with covalent C–S–C linkages, although one thione derivative structure has been reported .…”

Chelation Equilibria and π-Electron Delocalization in Neutral Hypercoordinate Organosilicon Complexes of Pyrithione

“…Selected bond distances and angles are given in Table S5. Both structures exhibit pseudotetrahedral coordination spheres and form a covalent bond between silicon and the hydroxylamine oxygen, as is also observed in their 1-oxo-2-pyridinone (OPO) analogues . This bonding arrangement contrasts with most known structures of simple hydrocarbon-based OPTO derivatives, which are N -oxides with covalent C–S–C linkages, although one thione derivative structure has been reported .…”

Synthesis and crystal structures of bis[1-oxopyridin-2-olato(1−)]bis(pentafluorophenyl)silicon(IV)–tetrahydrofuran–pentane (2/1/1), bis[1-oxopyridin-2-olato(1−)]bis( p -tolyl)silicon(IV), and dimesitylbis[1-oxopyridin-2-olato(1−)]silicon(IV)

“…As a result, Si OC bond dissociation would be expected to be inhibited as observed, which has been shown as part of the mechanism of isomerization of R 2 Si(OPO) 2 complexes. Similarly, interconversion of fac and mer isomers in the even more strongly chelated [Si(OPO) 3 ] + cation is not observed for likely the same reason (Kraft et al, 2015). Bite angles in homoleptic [Si(OPO) 3 ] + silyl cations range from 87.0-87.…”

“…Bite angles in homoleptic [Si(OPO) 3 ] + silyl cations range from 87.0-87. CN, and [Si(OPO) Structural Database (CSD;Groom et al, 2016), version 5.45, update Nov. 2023; refcodes RUTQUU, RUTRAB (Kraft et al, 2015) and QOXSIF (Tacke, Willeke, & Penka, 2001)], respectively, indicating even stronger chelate interactions in comparison with 1. The presence of only one isomer of 1 in solution is consistent with the crystallographic data having a common disorder ratio of 0.52 (2):0.48 (2) for both C1/N1 and C6/N2.…”

Neutral and Cationic Bis-Chelate Monoorganosilicon(IV) Complexes of 1-Hydroxy-2-pyridinone

“…In 4 – 6 , their OPO ligand disordered structures indicate the presence of two possible isomers, O­(N)- trans -O­(N) and O­(N)- trans -O­(C), with the disorder ratios indicating a slightly greater probability for the latter in each (see the Experimental Section). The OPO ligand bite angles in 4 – 6 (∼87°) are larger than those in 1 – 3 (∼85–86°) and indicate a stronger binding affinity as a likely consequence of the greater electrophilicity of the formed cations; they are comparable to those of the tris-chelate cation [Si­(OPO) 3 ] + , which range from 86.62 to 87.26° . The O 2 Si chelate ring and the OPO ligands form fold angles of 9.67(5) and 11.47(3)° in 4 , 12.39(8) and 12.68(10)° in 5 , and 7.79(5) and 9.32(3)° in 6 with the pyridine rings bending toward the alkyl group .…”

“…X-ray-quality crystals of each complex were obtained by mixing dilute solutions of each reagent in an appropriate solvent and allowing the solutions to stand from several hours to days at room temperature or were otherwise formed as fine white precipitates under more concentrated conditions. An attempt to prepare Si­(OPO) 2 Cl 2 by the reaction of SiCl 4 with 2 equiv of Me 3 Si­(OPO) in acetonitrile resulted in the isolation of the well-known stable tris-chelate [Si­(OPO) 3 ] + Cl – …”

Chelation Equilibria and π-Electron Delocalization in Neutral Hypercoordinate Organosilicon Complexes of Pyrithione

“…Selected bond distances and angles are given in Table S5. Both structures exhibit pseudotetrahedral coordination spheres and form a covalent bond between silicon and the hydroxylamine oxygen, as is also observed in their 1-oxo-2-pyridinone (OPO) analogues . This bonding arrangement contrasts with most known structures of simple hydrocarbon-based OPTO derivatives, which are N -oxides with covalent C–S–C linkages, although one thione derivative structure has been reported .…”

Synthesis and crystal structures of bis[1-oxopyridin-2-olato(1−)]bis(pentafluorophenyl)silicon(IV)–tetrahydrofuran–pentane (2/1/1), bis[1-oxopyridin-2-olato(1−)]bis( p -tolyl)silicon(IV), and dimesitylbis[1-oxopyridin-2-olato(1−)]silicon(IV)

“…As a result, Si OC bond dissociation would be expected to be inhibited as observed, which has been shown as part of the mechanism of isomerization of R 2 Si(OPO) 2 complexes. Similarly, interconversion of fac and mer isomers in the even more strongly chelated [Si(OPO) 3 ] + cation is not observed for likely the same reason (Kraft et al, 2015). Bite angles in homoleptic [Si(OPO) 3 ] + silyl cations range from 87.0-87.…”

“…Bite angles in homoleptic [Si(OPO) 3 ] + silyl cations range from 87.0-87. CN, and [Si(OPO) Structural Database (CSD;Groom et al, 2016), version 5.45, update Nov. 2023; refcodes RUTQUU, RUTRAB (Kraft et al, 2015) and QOXSIF (Tacke, Willeke, & Penka, 2001)], respectively, indicating even stronger chelate interactions in comparison with 1. The presence of only one isomer of 1 in solution is consistent with the crystallographic data having a common disorder ratio of 0.52 (2):0.48 (2) for both C1/N1 and C6/N2.…”

Neutral and Cationic Bis-Chelate Monoorganosilicon(IV) Complexes of 1-Hydroxy-2-pyridinone

“…In 4 – 6 , their OPO ligand disordered structures indicate the presence of two possible isomers, O­(N)- trans -O­(N) and O­(N)- trans -O­(C), with the disorder ratios indicating a slightly greater probability for the latter in each (see the Experimental Section). The OPO ligand bite angles in 4 – 6 (∼87°) are larger than those in 1 – 3 (∼85–86°) and indicate a stronger binding affinity as a likely consequence of the greater electrophilicity of the formed cations; they are comparable to those of the tris-chelate cation [Si­(OPO) 3 ] + , which range from 86.62 to 87.26° . The O 2 Si chelate ring and the OPO ligands form fold angles of 9.67(5) and 11.47(3)° in 4 , 12.39(8) and 12.68(10)° in 5 , and 7.79(5) and 9.32(3)° in 6 with the pyridine rings bending toward the alkyl group .…”

“…X-ray-quality crystals of each complex were obtained by mixing dilute solutions of each reagent in an appropriate solvent and allowing the solutions to stand from several hours to days at room temperature or were otherwise formed as fine white precipitates under more concentrated conditions. An attempt to prepare Si­(OPO) 2 Cl 2 by the reaction of SiCl 4 with 2 equiv of Me 3 Si­(OPO) in acetonitrile resulted in the isolation of the well-known stable tris-chelate [Si­(OPO) 3 ] + Cl – …”

Chelation Equilibria and π-Electron Delocalization in Neutral Hypercoordinate Organosilicon Complexes of Pyrithione

“…Selected bond distances and angles are given in Table S5. Both structures exhibit pseudotetrahedral coordination spheres and form a covalent bond between silicon and the hydroxylamine oxygen, as is also observed in their 1-oxo-2-pyridinone (OPO) analogues . This bonding arrangement contrasts with most known structures of simple hydrocarbon-based OPTO derivatives, which are N -oxides with covalent C–S–C linkages, although one thione derivative structure has been reported .…”

Synthesis and crystal structures of bis[1-oxopyridin-2-olato(1−)]bis(pentafluorophenyl)silicon(IV)–tetrahydrofuran–pentane (2/1/1), bis[1-oxopyridin-2-olato(1−)]bis( p -tolyl)silicon(IV), and dimesitylbis[1-oxopyridin-2-olato(1−)]silicon(IV)

“…As a result, Si OC bond dissociation would be expected to be inhibited as observed, which has been shown as part of the mechanism of isomerization of R 2 Si(OPO) 2 complexes. Similarly, interconversion of fac and mer isomers in the even more strongly chelated [Si(OPO) 3 ] + cation is not observed for likely the same reason (Kraft et al, 2015). Bite angles in homoleptic [Si(OPO) 3 ] + silyl cations range from 87.0-87.…”

“…Bite angles in homoleptic [Si(OPO) 3 ] + silyl cations range from 87.0-87. CN, and [Si(OPO) Structural Database (CSD;Groom et al, 2016), version 5.45, update Nov. 2023; refcodes RUTQUU, RUTRAB (Kraft et al, 2015) and QOXSIF (Tacke, Willeke, & Penka, 2001)], respectively, indicating even stronger chelate interactions in comparison with 1. The presence of only one isomer of 1 in solution is consistent with the crystallographic data having a common disorder ratio of 0.52 (2):0.48 (2) for both C1/N1 and C6/N2.…”

Neutral and Cationic Bis-Chelate Monoorganosilicon(IV) Complexes of 1-Hydroxy-2-pyridinone

“…In 4 – 6 , their OPO ligand disordered structures indicate the presence of two possible isomers, O­(N)- trans -O­(N) and O­(N)- trans -O­(C), with the disorder ratios indicating a slightly greater probability for the latter in each (see the Experimental Section). The OPO ligand bite angles in 4 – 6 (∼87°) are larger than those in 1 – 3 (∼85–86°) and indicate a stronger binding affinity as a likely consequence of the greater electrophilicity of the formed cations; they are comparable to those of the tris-chelate cation [Si­(OPO) 3 ] + , which range from 86.62 to 87.26° . The O 2 Si chelate ring and the OPO ligands form fold angles of 9.67(5) and 11.47(3)° in 4 , 12.39(8) and 12.68(10)° in 5 , and 7.79(5) and 9.32(3)° in 6 with the pyridine rings bending toward the alkyl group .…”

“…X-ray-quality crystals of each complex were obtained by mixing dilute solutions of each reagent in an appropriate solvent and allowing the solutions to stand from several hours to days at room temperature or were otherwise formed as fine white precipitates under more concentrated conditions. An attempt to prepare Si­(OPO) 2 Cl 2 by the reaction of SiCl 4 with 2 equiv of Me 3 Si­(OPO) in acetonitrile resulted in the isolation of the well-known stable tris-chelate [Si­(OPO) 3 ] + Cl – …”