Coordination diversity of N-phosphoryl-N′-phenythiourea (LH) towards CoII, NiII and PdII cations:: Crystal structure of ML2-N,S and ML2-O,S chelates

Thiourea, PhNHC(S)NHP(O)(OPri)(2) (LH) chelates of Co-II, Ni-II, and Pd-II ions have been obtained and investigated by single-crystal X-ray diffraction, UV, IR, NMR spectroscopy, and El mass-spectrometry. The unusual 1,3-NS-coordination via sulfur and NP(O) nitrogen atoms has been found in the trans-square-planar NiL2 and PdL2 complexes, whereas the 1,5-O,S-coordination is realized in the tetrahedral CoL2 complex. DFT calculations have revealed significant stabilization of the 1,3-N,S-structures due to stronger crystal field and the NH-O=P hydrogen bonds. (c) 2006 Elsevier B.V. All rights reserved.