Isomeric clusters [HOs3(CO)10(C18H11N6)] obtained from the reaction of [Os3(CO)10(CH3CN)2] with new tris-pyridyl-1,2,4-triazines

Novel tris-pyridyl-1,2,4-triazines were prepared from the corresponding pyridyl-amidrazone and 2,2′-pyridyl in good yields. Reaction of the triazines with [Os 3 (CO) 10 (CH 3 CN) 2 ] afforded to corresponding orthometallated cluster.► New clusters [HOs 3 (CO) 9 (C 18 H 11 N 6 )] as a way to enhance the potential NLO response of the ligand. ► Two new 1,2,4-triazines were obtained by a modification of the reported method. ► Crystal structures for two new as-triazines are determined. ► Reaction of the new triazines with [Os 3 (CO) 10 (CH 3 CN) 2 ] leads to 3- or 4-pyridyl C–H activation. ► Studies are undertaken to assess the enhancement of the NLO response for the new clusters.