SYNTHESIS OF 1-MOLYBDA-2-PHOSPHATRIAZOLINE AND 1-MOLYBDA-2-PHOSPHATRIAZIRIDINE DERIVATIVES VIA 1,3-DIPOLAR CYCLOADDITION OF ARYL AZIDES TO SIGMA(3), LAMBDA(4)-PHOSPHANEDIYL COMPLEXES

The reaction of [(2,4,6-tBu3-C6H2O)(HC=CCH2)]P=MoCp(CO)2 (1; R = 2,4,6 -tBu3C6H2O) with aryl azides R'N3 (2a, R' = C6H5, 2b, R' = 2,4,6-Me3C6 H2) affords the triazoline derivatives [(2, 4, 6 - tB u 3 C 6 H 2 O) ( H C = C C H 2)]-P-N=N-NR'-MoCp(CO)2 (3) via a 1,3-dipolar cycloadditio n reaction. Thermally induced dinitrogen elimination from 3 yields the 1 -molybda-2-phosphaaziridines [(2,4,6-tBu3C6H2O)(HC=CCH2)]P-NR'-MoCp -(CO)2 (4). Compounds 1, 3, and 4 each contain a 2-propynyl unit. Reac tion of each with CO2(CO)8 (5) gives (R)[(eta2-CH2C=CH)Co2(CO)6]P=MoCp (CO)2 (8), (R)-[(eta2-CH2C=CH)Co2(CO)6]P-N=N-NR'-MoCp-(CO)2 (6), and ( R)[(eta2-CH2C=CH)Co2(CO)6]-P-NR'-MOCP(CO)2(7), respectively. Complex 7 is also formed by thermal treatment of 6. The steric influence of the dicobaltatetrahedrane cluster unit in 8 toward the addition of RN3 (2 ) to the P-Mo pi system is discussed. The identities of all new compou nds have been documented by analytical as well as by spectroscopic (IR , MS, and H-1, P-31, and C-13 NMR) data; the X-ray structure of (R)[(e ta2-CH2C-CH)Co2(CO)6]}P-N=N-N(R')-MoCp-(CO)2 (6b; R' = 2,4,6-Me3C6H2) is reported.