Patent ID: 8273576

Claim:
A method for selective detection and quantification of Cr 6+ in a liquid sample, comprising: (i) exposing a divalent osmium (Os 2+ )-, iron (Fe 2+ )- or ruthenium (R 2+ )-based pyridyl complex capable of changing its oxidation state in response to a reduction of Cr 6+ to said sample, for a sufficient time period at the presence of H + ; (ii) recording absorption spectra of said pyridyl complex at the UV/visible spectral range, and (iii) monitoring the presence of Cr 6+ in said sample and determining its concentration according to the change in the absorption spectra of (ii) compared to a predetermined absorption spectra of said pyridyl complex, wherein said pyridyl complex is a charged tris-bipyridyl Os 2+ , Fe 2+ or R 2+ complex of the general formula I: wherein M is Os, Fe or Ru; n is the formal oxidation state of the osmium, iron or ruthenium, wherein n is 2 or 3; m is the positive charge of the tris-bipyridyl ligand, wherein m is an integer from 0 to 24, X is a counter anion selected from Br − , Cl − , F − , I − , PF 6 − , BF 4 − , OH − , ClO 4 − , SO 3 − CF 3 COO − , CN − , alkylCOO − , arylCOO − or a combination thereof; R 5 to R 28 is each independently hydrogen, halogen, hydroxyl, azido, nitro, cyano, amino, substituted amino, thiol, C 1 -C 10 alkyl, cycloalkyl, heterocycloalkyl, haloalkyl, aryl, heteroaryl, alkoxy, alkenyl, alkynyl, carboxamido, substituted carboxamido, carboxyl, protected carboxyl, protected amino, sulfonyl, substituted aryl, substituted cycloalkyl or substituted heterocycloalkyl, wherein at least one of said R 5 to R 28 is a group A or B: wherein group A is wherein group A is linked to the ring structure of the compound of general formula I via R 4 ; R 4 is cis/trans C═C, C≡C, N═N, C═N, N═C, C—N, N—C, alkylene, arylene or a combination thereof; R 3 is C or N; R 2 is absent or is hydrogen, alkyl, alkylene, aryl, arylene, OH, O-alkyl, O-alkylene or a combination thereof; R 1 is absent or is hydrogen, trialkoxysilane, trihalidesilane, thiol, COOH, COO − , Si(OH) 3 or phosphonate; group B is −O(CH 2 ) p —R 29 linked to the ring structure of the compound of general formula I via the oxygen, wherein p is an integer from 9 to 12; R 29 is hydrogen, trialkoxysilane, trihalidesilane, thiol, COOH, COO − , Si(OH) 3 or phosphonate; and any two vicinal R 5 -R 28 substituents, together with the carbon atoms to which they are attached, may form a fused ring system selected from cycloalkyl, heterocycloalkyl, heteroaryl or aryl, wherein said fused system may be substituted by one or more groups selected from C 1 -C 10 alkyl, aryl, azido, cycloalkyl, halogen, heterocycloalkyl, alkoxy, hydroxyl, haloalkyl, heteroaryl, alkenyl, alkynyl, nitro, cyano, amino, substituted amino, carboxamido, substituted carboxamido, carboxyl, protected carboxyl, protected amino, thiol, sulfonyl or substituted aryl; and said fused ring system may also contain at least one heteroatom selected from the group consisting of N, O and S.