MONO AND DINUCLEAR GOLD(I) COMPLEXES WITH NEUTRAL AND DEPROTONATED 1,4-BENZODIAZEPIN-2-ONES - CRYSTAL AND MOLECULAR-STRUCTURE OF (L-H)AU(PPH3).ET2O, WHERE L=1,3-DIHYDRO-7-NITRO-5-PHENYL-2H-1,4-BENZODIAZEPIN-2-ONE, NITRAZEPAM

The preparation of a series of neutral (L)AuCL (1a-3a) and cationic [(L)Au(PPh3)] [BF4] (1b-5b) gold(I) complexes is described (L = DIAZEPAM, 1; PRAZEPAM, 2; NITRAZEPAM, 3; LORAZEPAM, 4; NIMETAZEPAM, 5). In the presence of alkali, (PPh3)AuCl reacts with 1-unsubstituted 1,4-benzodiazepin-2-ones such as NITRAZEPAM (3) and LORAZEPAM (4) to give neutral gold(I) species (L-H)Au(PPh3) (3c and 4c). The benzodiazepine anion is bonded to Au via the N(1) atom, as shown, in the case of 3c, by X-ray analysis: (L-H)Au(PPh3)·Et2O, C33H25AuN3O3P· C4H10O, monoclinic, space group P21/c, a= 12.717(9), b=19.270(7), c=14.696(3) Å, β= 107.85(3)°, Z= 4. AuP = 2.238(1), AuN = 2.071(3) Å. The crystal structure was determined by standard methods and refined to R = 0.028 and Rw = 0.035 on the basis of 4456 unique reflections. p ]The complex 3c reacts with [(Ph3P)Au(S)][BF4], as obtained from (PPh3)AuCl and AgBF4 in methanol, to give the dinuclear cationic species [(Ph3P)Au{μ(L-H)}Au(PPh3)] [BF4] (3d) where the deprotonated NITRAZEPAM bridges two (Ph3P)Au groups through the N(1) and N(4) atoms. All the new derivatives were characterized by elemental analyses and spectroscopic methods (IR; 1H, 31P NMR).