Selenoether macrocyclic chemistry–syntheses and ligand properties of new small-ring Se3- and Se2N-donor macrocycles

The preparations of both open-chain and cyclic mixed-donor Sb/N ligands, MeN(CH2-2-C6H4)2SbMe (1), MeN(CH2-2-C6H4SbMe2)2 (2), CH2{CH2N(Me)CH2-2-C6H4SbMe2}2 (3) and CH2{CH2N(Me)CH2-2-C6H4}2SbMe (4), are described via reaction of chlorostibines with dilithio-reagents, and their spectroscopic properties established. Air-stable stibonium derivatives of (3) and (4) have been isolated by treatment of the compounds with excess MeI, which leads to quaternisation at the Sb atoms exclusively. A crystal structure of a bis(stibonium) derivative of (3), [CH2{CH2N(Me)CH2-2-C6H4SbMe3}2]I2, reveals hypervalency at Sb through long-range Sb...N interactions (ca. 2.87 A), giving pseudo-five-membered rings fused to the aromatic rings, and distorted trigonal bipyramidal coordination at Sb. The coordinating properties of compounds (1) to (4) have been investigated through their reactions with Cu(I), Mn(I), Mo(0) and Pt(IV) reagents, and for (1) and (4) by reaction with Fe(0), giving [Fe(CO)4(L)]. The spectroscopic data (IR, 1H, 13C{1H}, 55Mn, 63Cu, 95Mo and 195Pt NMR), mass spectrometry and microanalyses for this series of complexes confirm that coordination occurs via the Sb donor atoms in all cases, with N-coordination only present in fac-[Mn(CO)3(2)](CF3SO3). Crystal structures of [Cu(2)2]BF4, [Mo(CO)4(2)] and [PtMe3I(2)] confirm the coordination modes, showing (2) functioning as a wide-angle bidentate distibine. The structures also show the amine N-donor atoms in the complexes are involved in a hypervalent SbN interaction (ca. 3.0 A) with one of the coordinated Sb atoms in each ligand, leading to significant differences in the conformations of the carbon backbones linking the Sb and N atoms. Reaction of Na3[RhCl6].12H2O with one mol equiv. of (2), (3) or (4) leads to the bis-ligand complex [RhCl2(2)2]Cl and the 1 : 1 Rh : L complexes [RhCl2(3)]Cl and [RhCl3(4)], both of which involve coordination via the Sb and N donor atoms.

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“…We have recently utilised a similar strategy for the preparation of a range of small ring selenoether macrocycles. 21,22…”

Section: Ligandsmentioning

confidence: 99%

Preparation and properties of cyclic and open-chain Sb/N-donor ligands

et al. 2009

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“…69 Small ring Se 3 -and Se 2 N-donor macrocycle complexes [CrCl 3 (macrocycle)] and [CrX 2 ([16]aneSe 4 )][PF 6 ] (X = Cl, Br) have been prepared, and analysis of their ligand field spectra suggest that the selenoethers are weaker donors than the thioether analogues as expected. 86,89 Homogeneous olefin oligomerisation, especially selective trimerisation of ethene to produce 1-hexene, catalysed by chromium complexes containing tridentate SNS-donor ligands, NH{(CH 2 ) 2 SR} 2 (R = Ph, Cy, n-C 10 H 21 , etc. ), and activated with organoaluminium reagents, has attracted considerable recent research effort.…”

Section: Chromiummentioning

confidence: 99%

Developments in the chemistry of the hard early metals (Groups 1–6) with thioether, selenoether and telluroether ligands

2016

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The coordination chemistry of neutral thio-, seleno-and telluroether ligands towards the hard s-block, f-block and higher oxidation state early d-block metals has developed significantly over the 15 or so years. This has revealed several hitherto unknown classes of complexes and new insights into the chemistries of these hard-soft metal-ligand combinations. This Perspective describes the synthetic routes used to access such complexes and draws out their key structural features and spectroscopic properties. Where appropriate, applications of these species are also highlighted, including their use as single source precursors for the chemical vapour deposition of semiconducting metal chalcogenide thin films and as pre-catalysts for olefin polymerisation reactions. IntroductionThioether and selenoether ligands, which are neutral sulfur and selenium donors respectively, were for many years viewed as modest σ-donor ligands that formed complexes with the softer later d-block elements in low or medium oxidation states, or with post transition metals such as silver or mercury.1,2Complexes of the early d-block metals were mostly limited to low valent organometallics or carbonyls. The chemistry of telluroethers was very little explored, in major part a reflection of their limited availability and, for the alkyl telluroethers in particular, their extremely malodorous nature. 2,3The R2Te ligands are also oxygen sensitive (in contrast to the air stable R2S or R2Se), modest reducing agents and prone to cleavage of the CTe bond upon reaction with some metal centres. Even today, their chemistry remains much less extensive than that of their lighter analogues. 4 Major developments in the syntheses and coordination chemistry of macrocyclic thioethers considerably extended the range and stability of complexes containing metal centres across the d-block. More recent work has resulted in complexes of chalcogenoethers with many of the p-block elements,

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“…132 A range of macrocycles offering Se 3 and Se 2 N donor sets complex Pt II alkyls as well as the harder CrCl 3 moiety. 133 The 12-membered macrocycle [((p-MeOC 6 H 4 ) 2 Te) 2 (m-O)(m-cycPO 2 )(m 4 -Cl)] 2 has been synthesised and underwent halide exchange when reacted with NaI. 134…”

Section: Macrocyclesmentioning

confidence: 99%