The synthesis, characterization and X-ray crystal structure of the rhenium organodiazenido, organodiazene complex [ReCl2(PPh(3))(N=NC5H4N)(HN=NC5H4N)]

The reaction of the Re(III) complex [ReCl3(N=NC5H4NH)(HN=NC5H4N)] (1) with triphenylphosphine and a proton scavenger in methanol gives the neutral complex [ReCl2(PPh(3))(N=NC5H4N)(HN=NC5H4N)] (2). The neutral, six-coordinate complex contains a singly-bent pyridyldiazenido ligand and a bidentate, organodiazene ligand that is chelated through the pyridine nitrogen atom, The IR spectrum displays a series of strong absorptions in the 1600-1150 cm(-1) region characteristic of the organohydrazide ligands. The FAB(+) mass spectrum displays the protonated parent ion of 733 m/z and the ion [ReCl(PPh(3))(N=NHC5H4N)(HN=NC5H4N)](+) of 697 m/z. The X-ray crystal structure of this complex displays a cis arrangement of chloride ligands with the pyridine nitrogen atom of the organodiazene chelate located in the position trans to the pyridyldiazenido ligand. Crystal data for ReCl2PN6C28H26: monoclinic space group P2(1)/n, a=10.263(2), b=14.938(3), c=19.650(4) Angstrom, beta=97.54(3)degrees with Z=4 to give V=2995.5(15) Angstrom(3). The coordination geometry is distorted octahedral. The Re-N bond length to the pyridine nitrogen atom of the organodiazene chelate is 2.147(15) Angstrom, while the Re-N bond to the diazene-alpha-nitrogen atom is 1.915(21) Angstrom. The N-N bond length of this ligand is 1.340(26) Angstrom, indicative of multiple bonding within the chelated ligand, The Re-N bond length of the pyridyldiazenido ligand is 1.778(14) Angstrom, and the N-N bond length is 1.212(22) Angstrom, again reflecting the multiple bonding throughout the singly-bent, organodiazenido unit. The bond angle of the Re-N-N linkage is 172.8(13)degrees.