SQUID Magnetic Measurements on#1 -z+1,x-1/2,-y+1/2 Positional parameters and B(eq) for 2.62(5)2.40(5) 2.1(4) 2.4(4) 2.4(4) 2.3(4) 2.0(4) 2.0(4) 2.1(5) 2.7(6) 2.5(5) 3.2(6) 3.0(6) 3.9(7) 3.1(6) 4.3(7) 2.5(5) 3.7(6) 2.8(6) 3.1(6) 3.8(6) 3.3(6) 2.2(5) 2.2(5) 3.0(6) 2.6(5) 2.9(6) 3.5(6) 3.1(6) 3.7(7) 2.8(6) 3.3(6) 3.0(6) 2.5(5) 2.8(6) 3.0(6) 2.4(5) 2.6(5) 2.9(6) 2.5(5) 3.8(7) 3.3(6) 4.0(7) 3.7(7) 3.2(6) 3.2(6) 2.4(5) 2.9(6) 2.6(5) 0 1996 American Chemical Society J. Am. Chem. Soc. VI 18 Page8623 Laplaza Supplemental Page 9Positional parameters and B(eq) for 0.044(7) 0.038 (7 1.960 (7) 1.964 (7) 1.977 (7) 1.970 (7) 1.968 (7) 1.956 (7) 1.42 (1) 1.50(1)1.42 (1) 1.48 (1) 1.44 (1) 1.49 ( 122.8(9)122 (1) 117 ( 120 (1) 120 (1) 120 (

Cleavage of the relatively inert dinitrogen (N(2)) molecule, with its extremely strong N identical withN triple bond, has represented a major challenge to the development of N(2) chemistry. This report describes the reductive cleavage of N(2) to two nitrido (N(3-)) ligands in its reaction with Mo(NRAr)(3), where R is C(CD(3))(2)CH(3) and Ar is 3,5-C(6)H(3)(CH(3))(2'), a synthetic three-coordinate molybdenum(III) complex of known structure. The formation of an intermediate complex was observed spectroscopically, and its conversion (with N identical withN bond cleavage) to the nitrido molybdenum(VI) product N identical withMo(NRAr)(3) followed first-order kinetics at 30 degrees C. It is proposed that the cleavage reaction proceeds by way of an intermediate complex in which N(2) bridges two molybdenum centers.

Of great si&icance in both biological and synthetic systems are two-electron processes in which a divalent atom such as oxygen is completely transferred between two reaction partners.' Until now, the endogenous three-electron atom transfer process has been limited to examples of intermetallic nitrogen atom transfer as exemplified by the reaction (TTP)Cr + N=Mn(TTP) -(TTP)CFN 4-Mn(TTP).2 In the present work we establish a three-electron redox process in which a nitrogen atom from nitrous oxide is transferred to a molybdenum(II1) coordination complex.The complex Mo(NRAr)3 (1; R = C(CD3)2CH3, Ar = 33-C6H3Me2) was prepared for this work since d3 1 could conceivably engage in three-electron redox processes. Of the various possibilities, N-atom transfer was a particularly attractive target since stable nitrido complexes of the kind N=MoX3 (X = alkyl,3 amide? or &oxide5) are known. In a typical preparation, M o C~~( T H F )~~ (4.164 "01) and Li(NRAr)(OEt2)7 (8.315 m o l ) were added to 70 mL of cold (-100 "C) ether, and the mixture was stirred for 2.5 h after warming to 28 "C. The precipitated LiCl and excess MoC13(THF)3 were removed by filtration. Analysis of the filtrate by 2H NMR spectroscopy showed only one major product, with a relatively sharp (Avll2 = 35 Hz) signal at 64.6 ppm corresponding to the 2H-labeled tert-butyl groups in paramagnetic M O ( N R A~)~.~ The filtrate was concentrated and cooled to -35 "C under an argon atmosphere to produce orange-red, crystalline Mo(NRAr)3 (mp 126-128 "C, yield 70%)? MO(NR&)3 (1) is extremely oxygen-and (1) Holm, R. H.; Donahue,