FUNCTIONALIZED PHOSPHINE-PHOSPHINIMINES AS HETEROATOMIC LIGANDS - SYNTHESIS, CHARACTERIZATION, AND REPRESENTATIVE X-RAY STRUCTURES OF THE PHOSPHINE-PHOSPHINIMINES PH(2)PCH(2)PPH(2)=NAR [AR=5-F,2,4-(NO2)(2)C6H2, 4-(CN)C6F4] AND STRUCTURE OF THE RHODIUM(I) COMPLEX CL(CO)RHP(PH)(2)CH(2)PPH(2)=NC6F4-4-CN

Reaction of the (trimethylsilyl)phosphinimine-phosphine Me(3)SiN=PPh(2)CH(2)PPh(2) with nitro-fluoro aromatics and aromatic fluoro nitriles (containing at least one activated fluorine on the position which becomes, as the point of attachment to the imine nitrogen, position 1 of the ring) in refluxing toluene gave the phosphinimine-phosphines RN=PPh(2)CH(2)PPh(2) [R = 2,5-(CN)(2)C6F3, 3,4-(CN)(2)C6F3, 5-F-2,4-(NO2)(2)C6H2, 2,4-(NO2)(2)C6H3] The compounds 2 (R = 4-(CN)C6F4) and 4 (R = 5-F-2,4-(NO2)(2)C6H2) have been structurally characterized. Data for 2 (at 23 degrees C): monoclinic, P2(1)/c (No. 14), a 11.065(4) Angstrom, b = 30.218(10) Angstrom, c = 9.302(4) Angstrom, beta = 115.37(3)(degrees), V = 2810 Angstrom(3), Z = 4, R(1) = 0.070, R(2) = 0.080. The P=N bond is 1.567(4) Angstrom, and the P-V-N-C(phenyl) angle is 132.9(3)degrees. The p(III)-C-P-V angle is 110.9(2)degrees. Data for 4 (at -80 degrees C): monoclinic Cc (No. 9), a = 18.957(5) Angstrom, b = 12.783(8) Angstrom, c 11.607(4) Angstrom, beta = 102.87(3)degrees, V = 2742 Angstrom(3) Z = 4, R(1) = 0.052, R(2) = O.049. The P=N, bond is 1.589(5) Angstrom, and the P-V-N-C(phenyl) angle is 128.8(4)degrees. The P-V-C-P-III angle is 113.2(3)degrees. In both 2 and 4 the fluoro aromatic ring lies in proximity to one of the phenyl rings on P-III and these two rings are eclipsed. These compounds react readily with [Rh(CO)(2)Cl](2) to form the chelated Rh complexes of the form RN=PPh(2)CH(2)PPh(2)Rh(CO)Cl with R as above. The R = 4-(CN)C6F4 derivative, 10, has been structurally characterized. Data for 10 (at 21 degrees C): monoclinic C2/c (No. 15), a = 42.499(4) Angstrom, b = 9.020(1) Angstrom, c = 20.257(2) Angstrom, beta = 111.79(1)0 V = 7210.4 Angstrom(3), Z = 8, R(1) = 0.036, R(2) = 0.056. The complex shows the square planar geometry around Rh-I with the CO cis to the phosphine. Bond angles and lengths are typical for this square planar chelate complex structure. The P(2)-N(1) distance of 1.616(2) Angstrom in the complex (approximately 0.05 Angstrom longer than that in the free ligand) is normal for a coordinated iminophosphoranyl group. The directly bound Rh-P-III distance of 2.2132(8) Angstrom also lies within the range found in many Rh(I) phosphine complexes of the type P2Rh(CO)Cl.