Synthesis and characterization of organometallic compounds : I. cyano- and isocyanoarene iron(II) and molybdenum(0) complexes; II. 1,3,5-trimethylcalix[4]arene and its chromium and molybdenum derivatives

Abstract

The synthesis and spectroscopic characterization of a series of mono- and bimetallic complexes containing (╖5-C5H5)Fe(C0)2 and Mo(Ph2PCH2CH2PPh2)2 units and bridging or terminal isocyano and cyano arene ligands, a zerovalent organometallic polymer of molybdenum, and 1, 3, 5-trimethylcalix [4] arene and its chromium and molybdenum derivatives are reported. The mono-iron and di-iron complexes may be prepared via reaction of [(╖^5-C5H5)Fe(CO)2]Cl or [(╖^5-C5H5)Fe(CO)2]2 with p-CNC6H4X or p-NCC6H4X (X= Cn, NC, Cl) in the presences of silver (I) salts. The electron-rich molybdenum complexes are synthesized via replacement of dinitrogen in Mo(N2)2(Ph2PCH2CH2PPh2)2 by isocyanides (e.g., p - CNC6H4NH2, p - CNC6H4Cl). The organometalli polymer [Mo(μ-CNC6H4NC (Ph2PCH2CH2PPh2)2]n, is obtained by the reaction of Mo(N2)2(Ph2PCH2CH2PPh2)2 with p-diisocyanobenzene. The 1 H and 13C NMR and IR spectroscopic data for each complex establishes its structure and suggests that the isocyano and cyano groups bind to the metal centers in the linear terminal coordination mode and that there forms an extended π- conjugation between the bridges and metal centers. The X-ray crystal structures of the complexes [(╖^5-C5H5)Fe(CO)2(p - CNC6H4Cl)]PF6 (C14ClF6FeH9NO2P; a =7.0833(5) A, b = 14.903(1) A, c = 16.591(2) A, ß=98.674(7)°; V =1731.4(3) A3; monoclinic; P21/c; Z = 4) and trans-[Mo( p - CNC6H4Cl)2(Ph2PCH2CH2PPh2)2] (C66Cl2H56MoP4; a =29.182(2) A, b = 12.324(1) A, c = 19.205(2) A, ~=94.77(1)° ; V = 6883(1) A3; monoclinic; C2/c; Z = 4) have been determined and confirm that they have the expected structures including essentially linear isocyanide ligands.1,3,5-trimethylcalix[4]arene was prepared by a tintetrachloride-catalyzed reaction of 2-chloromethyl-1,3,5-trimethylbenzene. The organometallic macromolecules 1,3,5-timethylcalix[4]arenechromiumtricarbonyl and 1,3 5,-trimethylcalix[4]arenemolybendum-tricarbonyl are synthesized by the reaction of 1, 3,5-trimethylcalix[4]arene with the appropriate metal hexacarbonyl in refluxing dioxane. They have been partially characterized by spectroscopic techniques and are shown to contain Cr- or Mo-arene π bonds.