Synthesis and characterization of alkali metal iminophosphoranomethanide complexes

Herein we report the synthesis of three sets of alkali metal complexes with the iminophosphoranomethanide ligands {CH(SiMe 3 )P(Ph) 2 - - NSiMe 3 } - ( TMS NPC-H) and {CH(SiMe 2 t Bu)P(Ph) 2 - - NSiMe 3 } - ( TBDMS NPC-H), the latter of which is first reported here. The compounds of general formula [M( R NPC-H)] ( 3-M and 4-M ; M = Li, Na, K) were obtained via a protonolysis reaction between an alkyl reagent ( n -butyllithium, benzylsodium, or benzylpotassium) and the proligand. All resulting compounds were characterized by multinuclear NMR, IR spectroscopy, elemental analysis and single crystal X-ray diffraction. We also attempted to prepare the separated ion pairs of [M( TMS NPC-H)] with the matched crown ethers, and obtained the 'ate' complexes [Li(12-crown-4) 2 ] + [Li ( TMS NPC-H) 2 ] - ( 5-Li ) and [Na(15-crown-5) 2 ] + [Na( TMS NPC-H) 2 ] - ( 5-Na ), the coordination polymer [{K(18crown-6) 2 }{K( TMS NPC-H)(18-crown-6)}( TMS NPC-H)] infinity ( 6 ) and separate ion pair complex [K(15-crown5) 2 ] + [ TMS NPC-H] - ( 7 ). 5-Li is an unusual lithium-lithiate crown ether species, whilst 5-Na represents the first example of a sodium-sodiate crown-ether complex.