Novel structural arrangement for divalent metal phosphonates: synthesis of tert-butylphosphonates and structure of Co[(CH3)3CPO3]·H2O

Abstract

The synthesis and characterization of new divalent metal tert-butylphosphonates are described: M^II[(CH₃)₃CPO₃]·xH₂O [M^II= Co, Mn (x= 1) M^II= Zn (x= 2/3)] and Cu_1.75O_0.75[(CH₃)₃CPO₃]·H₂O. Co[(CH₃)₃CPO₃]·H₂O crystallizes in the monoclinic space group P2₁/c with a= 12.256(1)Å, b= 17.939(1)Å, c= 10.769(1)Å, β= 93.57(1)°, V = 2363.1 (4)ų, Z= 12, with R= 0.064 and R_w= 0.075 for 1805 observed reflections, according to the criterion I > 3σ(I). The layer arrangement of this new phase is different from that observed in the case of the n-alkyl M^II( RPO₃)·H₂O analogues owing to the steric effect of the bulky tert-butyl group. The structural relationship between the cobalt, manganese and zinc compounds is discussed. The observed magnetic moments are consistent with the presence of high-spin Mn^II or Co^II and with the existence of both octahedral and tetrahedral environments about these metals.