Bis(arylimido) Molybdenum(VI) Amidinate and Guanidinate Complexes; Molecular Structures of [(ArN)2MoMe{N(Cy)C[N(i-Pr)2]N(Cy)}] (Ar = 2,6-i-Pr2C6H3; Cy = Cyclohexyl) and [(2,6-i-Pr2C6H3N)2MoCl2] · [NH=C(C6H5)CH(SiMe3)2]

Abstract

The reaction of [(ArN) 2 MoCl 2 ]´DME (Ar = 2,6-iPr 2 C 6 H 3 ) (1) with lithium amidinates or guanidinates resulted in molybdenum(VI) complexes [(ArN) 2 -MoCl{N(R 1 )C(R 2 )N(R 1 )}] (R 1 = Cy (cyclohexyl), R 2 = Me (2); R 1 = Cy, R 2 = N(i-Pr) 2 (3); R 1 = Cy, R 2 = N(SiMe 3 ) 2 (4); R 1 = SiMe 3 , R 2 = C 6 H 5 (5)) with five coordinated molybdenum atoms. Methylation of these compounds was exemplified by the reactions of 2 and 3 with MeLi affording the corresponding methylates [(ArN) 2 MoMe{N(R 1 )C(R 2 )N(R 1 )}] (R 1 = Cy, R 2 = Me (6); R 1 = Cy, R 2 = N(i-Pr) 2 (7)). The analogous reaction of 1 with bulky [N(SiMe 3 )C(C 6 H 5 )-C(SiMe 3 ) 2 ]Li´THF did not give the corresponding metathesis product, but a Schiff base adduct [(ArN) 2 MoCl 2 ][ NH=C(C 6 H 5 )CH(SiMe 3 ) 2 ] (8) in low yield. The molecular structures of 7 and 8 are established by the X-ray single crystal structural analysis. H 5 (5)) mit fu È nffach koordinierten Molybda È n Atomen. Durch die Reaktion von 1 und 2 mit MeLi wurden die entsprechenden Methylate [(ArN) 2 MoMe{N(R 1 )C(R 2 )N(R 1 )}] (R 1 = Cy, R 2 = Me (6); R 1 = Cy, R 2 = N(i-Pr) 2 (7)) erhalten. In einer analogen Reaktion von 1 mit dem sterisch anspruchsvollen Lithiumsalz des 1-Azaallylliganden [N(SiMe 3 )C(C 6 H 5 )C(SiMe 3 ) 2 ]LiT HF konnte nicht das entsprechende Metatheseprodukt, sondern ein Addukt an die Schiffsche Base in geringer Ausbeute dargestellt werden [(ArN) 2 MoCl 2 ]´[NH=C(C 6 H 5 )-CH(SiMe 3 ) 2 ] (8). 7 und 8 wurden durch Einkristallro È ntgenstrukturanalysen charakterisiert.