s-Block metal complexes of PC(H)P-bridged chalcogen-centred methanides: comparisons with isoelectronic PNP-bridged monoanions

This Perspective compares the chemistries of s-block metal complexes of isoelectronic PC(H)P- and PNP-bridged, chalcogen-centred monoanions with a focus on the unique behavior of the C(H)-bridged systems.

PNacPNacE: (E = Ga, In, Tl) – monomeric group 13 metal(i) heterocycles stabilized by a sterically demanding bis(iminophosphoranyl)methanide

Monomeric group 13 metal(i) complexes of gallium, indium and thallium stabilised by a sterically demanding bis(iminophosphoranyl)methanide ligand have been prepared and characterised.

Synthesis of a labile sulfur-centred ligand, [S(H)C(PPh2S)2](-): structural diversity in lithium(i), zinc(ii) and nickel(ii) complexes

A high-yield synthesis of [Li{S(H)C(PPh2S)2}]2 [Li2·(3)2] was developed and this reagent was used in metathesis with ZnCl2 and NiCl2 to produce homoleptic complexes 4 and 5b in 85 and 93% yields, respectively. The solid-state structure of the octahedral complex [Zn{S(H)C(PPh2S)2}2] (4) reveals notable inequivalence between the Zn-S(C) and Zn-S(P) contacts (2.274(1) Å vs. 2.842(1) and 2.884(1) Å, respectively). Two structural isomers of the homoleptic complex [Ni{S(H)C(PPh2S)2}2] were isolated after prolonged crystallization processes. The octahedral green Ni(ii) isomer 5a exhibits the two monoprotonated ligands bonded in a tridentate (S,S',S'') mode to the Ni(ii) centre with three distinctly different Ni-S bond lengths (2.3487(8), 2.4500(9) and 2.5953(10) Å). By contrast, in the red-brown square-planar complex 5b the two ligands are S,S'-chelated to Ni(ii) (d(Ni-S) = 2.165(2) and 2.195(2) Å) with one pendant PPh2S group. DFT calculations revealed that the energetic difference between singlet and triplet state octahedral and square-planar isomers of the Ni(ii) complex is essentially indistinguishable. Consistently, VT and (31)P CP/MAS NMR spectroscopic investigations indicated that a mixture of isomers exists in solution at room temperature, while the singlet state square-planar isomer 5b becomes favoured at -40 °C.

Synthesis and structural characterization of monomeric mercury(ii) selenolate complexes derived from 2-phenylbenzamide ligands

The present work describes the synthesis and structural characterization of mercury selenolate complexes derived from 2-phenylbenzamide ligands and their isolation in monomeric form for the first time.

Instability of metal 1,3-benzodi(thiophosphinoyl)methandiide complexes: formation of hafnium, tin and zirconium complexes of 1,3-benzodi(thiophosphinoyl)thioketone dianionic ligand [1,3-C6H4(PhPS)2CS]2−

The reaction illustrates that the metal centre and ligand substituents are crucial for the stabilization of a C_methandiideHf bond.

Syntheses, structures and flexible coordination of sterically demanding di- and “tri”-lithiated methandiides

Sequential lithiation of a sterically demanding bis(iminophosphoranyl)methane afforded di- and trianionic methandiide lithium complexes and their structures and coordination behaviour have been studied with solid state and solution methods.

Synthesis and stability of Li/Cl carbenoids based on bis(iminophosphoryl)methanes

Bis(iminophosphoryl) substituted Li/Cl carbenoids – accessable via different preparation methods – show high thermal stabilities, which however depend on the N-substituent.