Synthesis, characterisation and reactivity of group 2 complexes with a thiopyridyl scorpionate ligand

Abstract

Herein we report the reactivity of the proligand tris(2-pyridylthio)methane (HTptm) with various Alkaline Earth (AE) reagents: 1) dialkylmagnesium reagents and 2) AE bis-amides (AE = Mg-Ba). Heteroleptic complexes of general...

Structural Investigation of Magnesium Complexes Supported by a Thiopyridyl Scorpionate Ligand

“…However, it would appear that in the absence of a sixth coordination point, the magnesium adopts a distorted trigonal bipyramidal geometry. The Mg–C distances in 1-X [Cl: 2.427(11); Br: 2.231(11); I: 2.231(10) Å] are similar to the analogous Mg–C bond in 2 [2.303(4) Å] and quite close to that observed for the related [Zn(Tptm)(Cl)] complex prepared by Kinoshita and co-workers [2.19(2), 2.213(6) Å] [ 14 ] and [Mg(Tptm){N(SiMe 3 ) 2 }] [2.303(4) Å] [ 30 ]. The Mg–N py bond distances [Cl: 2.186(11)–2.204(10); Br: 2.155(9)–2.219(9); I: 2.177(8)–2.182(8) Å] also fall within the range observed for analogous complexes [2.203(2)–2.305(2) Å] [ 30 , 31 ].…”

“…The Mg–C distances in 1-X [Cl: 2.427(11); Br: 2.231(11); I: 2.231(10) Å] are similar to the analogous Mg–C bond in 2 [2.303(4) Å] and quite close to that observed for the related [Zn(Tptm)(Cl)] complex prepared by Kinoshita and co-workers [2.19(2), 2.213(6) Å] [ 14 ] and [Mg(Tptm){N(SiMe 3 ) 2 }] [2.303(4) Å] [ 30 ]. The Mg–N py bond distances [Cl: 2.186(11)–2.204(10); Br: 2.155(9)–2.219(9); I: 2.177(8)–2.182(8) Å] also fall within the range observed for analogous complexes [2.203(2)–2.305(2) Å] [ 30 , 31 ]. In all three 1-X complexes, the geometry around the metal atom can be described as mer-mer with the three nitrogen atoms forming one meridional plane and the two halide atoms and methanide carbon forming the other.…”

“…The Mg–C distance [2.265(15) Å] is slightly longer than in unsolvated 1-I , but still within the range of the values above. The Mg–N py bond distance [2.213(13)–2.232(12) Å] is also slightly longer than the dimeric form but within the typical range [ 30 , 31 ].…”

“…The detachment of a pyridyl arm from the Tptm scaffold has been previously observed by Kinoshita and co-workers when HTptm was reacted with FeI 2 in the presence of Et 3 N and subsequent treatment with AgPF 6 , leading to an equilibrium between the carbene complex [Fe{C(S- We then decided to use a different approach for the synthesis of magnesium complexes involving a single-step protonolysis reaction. Protonolysis methodologies involving Grignard reagents are a common synthetic strategy in AE coordination and organometallic chemistry [30]. Hence, HTptm was reacted with selected Grignard We then decided to use a different approach for the synthesis of magnesium complexes involving a single-step protonolysis reaction.…”

“…We then decided to use a different approach for the synthesis of magnesium complexes involving a single-step protonolysis reaction. Protonolysis methodologies involving Grignard reagents are a common synthetic strategy in AE coordination and organometallic chemistry [30]. Hence, HTptm was reacted with selected Grignard reagents (i.e., i PrMgCl, MeMgBr and MeMgI) in diethyl ether at room temperature (Scheme 3), producing the target complexes [Mg(Tptm)(Cl)] (1-Cl), [Mg(Tptm)(Br)] (1-Br) and [Mg(Tptm)(I)] (1-I) with the concomitant formation of propane or methane.…”