Seven-coordinate complexes of molybdenum(II) and tungsten(II) containing pyrazole as a ligand

✍ Scribed by Paul K. Baker; Marit van Kampen; Christina Roos; Julia Spaeth

• Publisher: Springer
• Year: 1994
• Tongue: English
• Weight: 352 KB
• Volume: 19
• Category: Article
• ISSN: 0340-4285
• DOI: 10.1007/bf00161881

✦ Synopsis

Equimolar quantities of [MI2(CO)3(NCMe)2 ] (M = Mo or W) and C3H4N2 (pyrazole) react in CH2C12 at room temperature to give the iodo-bridged dimers [M(#-I)(CO)3(C:~H~N2)]2 (I) and (2). Two equivalents of C3H4N 2 react with [MIz(CO)a(NCMe)2] (M = Mo or W) to give the bis(pyrazole) complexes [MIz(CO)3(C3HgN2)23 (3) and (4) in good yield. Three and four equivalents of pyrazole react with [MoI2(CO)3(NCMe)2] to give the cationic complexes [MoI(CO)3(C:~H~N2)3]I (5) and [MoI(CO)z(C3H4N2)4]I (6), respectively. The mixed ligand complexes [MIz(CO)3(C3HgN2)L-I (M = Mo or W; L = PPh 3, AsPh3 or SbPh 3) (7)-( 12) are prepared by reacting equimolar amounts of [MI2(CO)3(NCMe)2] and L in CH2C12 at room temperature, followed by an in situ reaction with one equivalent of C3H4N 2. The Mo SnC13 complex [MoCI(SnC1o)(CO)3(C3H4Nz) 2] (I3)is prepared in an analogous manner using acetone as the solvent, whilst the mixed ligand compound [MoCI(SnCt3)-(CO)3(C3H4Nz)(PPh3)] ( 14) was prepared by treating the dimeric complex [Mo(#-C1)(SnC13)(CO)3(PPh3)]2 with two equivalents of C3H4N 2. All the new complexes were characterised by elemental analysis (carbon, hydrogen and nitrogen), i.r. and 1H n.m.r, spectroscopy.