A series of half-sandwich ruthenium(H) complexes containing kappa(3) (N,N,N)-hydridotris(pyrazolyl)borate (kappa(3)(NNN)-Tp) and the water-soluble phosphane 1,3,5-triaza-7-phosphaadamantane (PTA) [RuX[kappa(3)(N,N,N)-Tp)(PPh3)(2-n)(PTA)(n)] (n = 2, X = Cl (1), n = 1, X = Cl (2), I (3), NCS (4), H (5)) and [Ru{kappa(3)(N,N,N)-Tp}(PPh3)(PTA)L][PF6] (L = NCMc (6), PTA (7)) have been synthesized. Complexes containing 1-methyl-3,5-diaza-1-azonia-7-phosphaadamantane(m-PTA) triflate [RuCl{kappa(3)(N,N,N)-Tp}(m-PTA)(2)][CF3SO3](2) (8) and [RuX{kappa(3)(N,N,N)-Tp) (PPh3)(m-PTA)][CF3SO3] (X = Cl (9), H (10)) have been obtained by treatment, respectively, of complexes 1, 2 and 5 with methyl triflate. Single crystal X-ray diffraction analysis for complexes 1, 2 and 4 have been carried out. DNA binding properties by using a mobility shift assay and antimicrobial activity of selected complexes have been evaluated. (c) 2007 Elsevier Ltd. All rights reserved.