SOLID-STATE PHOTOCHEMISTRY AND STRUCTURE OF TRANS-(ET3P)2NI(N3)2 - PHOTODEPOSITION OF NICKEL

The photochemistry and stereochemistry of trans-(Et3P)2Ni(N3)2 have been investigated in the solid state. A single-crystal X-ray diffraction study of trans-(Et3P)2Ni(N3)2 shows that it crystallizes in the orthorhombic space group Pbc2(1) with a = 7.7011 (11) angstrom, b = 15.7112 (22) angstrom, c = 16.7813 (13) angstrom, and Z = 4 at 296 K (R(F) = 0.030 for 1231 data, I(o) greater-than-or-equal-to 2.5-sigma(I(o)); N(var) = 132). The mechanism of this photoreaction has been studied at room temperature, 77 K, and 20 K. Photolysis into the d-d absorption resulted in the formation of ion-paired [(Et3P)2Ni(N3)]+[N3]-. Recoordination was achieved with UV (lambda > 310 nm) photolysis. Excitation of the charge-transfer bands of trans-(Et3P)2Ni(N3)2 resulted in the formation of a species containing both bridging and terminal azide groups, [(Et3P)Ni(N3)2]2. Prolonged photolysis of the surface resulted in the loss of all ligands from the nickel. Analysis of the resultant film by Auger spectroscopy showed the production of nickel covered by a NiO layer and established the loss of all PEt3 and nitrogen from the surface.