Black geyser in deep sea hydrothermal vent. This  serves as the primitive environment on young earth and life still exists in such hostile niche with high hydrostatic pressure and high temperature under anoxic condition in the dark. The extremozymes found there were modeled as:

Functional model of P.furious ferredoxin aldehyde oxidoreductase

A model for formate dehydrogenase

Feed Stock Chemistry

Bacterial Origin:                                                                                                                                    Top

TMNO Reductase

Mo-cofactor from oxidised TMANOR

Nitrate Reductase                                                                                                                                            Top

Chemistry of [Et₄N][Mo^IV(SPh)(PPh₃)(mnt)₂] as an Analogue of Dissimilatory Nitrate Reductase with Its Inactivation Similar to
Single Point Mutation

Polysulfide Reductase                                                                                                                                      Top

Structural and Functional Analogue of the Active Site of Polysulfide
Reductase from Wolinella succinogenes

Mechanism

Eucarial origin:                                                                                                                                                    Top

Hepatic Sulfite Oxidase

How works in mitochondria

Native cofactor in active site                           Supper imposed native and half reduced synthetic model

This reaction follows Michaelis -Menten Kinetics with  sulfate and phosphate inhibition similar to native protein

 Properties  of the synthesized complexes with the understanding of structure-function relationship are subjected to  structural studies like detailed spectroscopic analysis followed by single crystal X-ray crystallography. Detailed redox  reactions are studied to evaluate the basis for atom or electron transfer reactions. A rare  type of induced electron reactions  are also of interest to us. The  kinetics of  reactions with  native substrates or model substrates are followed using  synthesized systems with inhibition studies. Model active site-substrate interactions are correlated with electrostatic potential computations to understand in vivo enzymatic reactions. Current and sustained studies include to model (with the theme: 'stabilization of unusual oxidation states of transition metals' involving green chemistry): nitrogenase, molybdenum and tungsten dependent pterin(cofactor) containing oxido-reductase class of enzymes, non-redox enzyme acetyelene hydratase, hemo-proteins ( heme as prosthetic group) like cytochrome P-450, NO-synthase, cytochrome-c oxidase, nitrophorin, cofactor F430, and methane monooxygenase.

Tetrakis-cyclohexyl porphyrinogen

Tetrakis-cyclohexyl Fe(III)porphyrinogen

Tetrakis-cyclohexyl Fe(II)-Br porphyrinogen                                      Tetrakis-cyclohexyl Fe(II)-I porphyrinogen

Reversible Penta- and Hexacoordination Motifs in [Co(TMPP)] Resulting in Interchange of 1D and 2D Supramolecular Designs

pH Dependent Interconversion of Dimeric and Monomeric Moybdenum(IV) / Tungsten(IV) Bis(dithiolene) Complexes .   

Metal clusters : Synthesis of homonuclear and heteronuclear metal sulfido and oxo clusters. Metal sulfido cuboidal to cubane core conversion  using electron precise rule. Synthesis of water soluble molybdenum and tungsten Keplerate . Copper -molybdenum antagonism in Teart disease, therapeutic use of thiomolybdate in Wilson disease. Structural model,  [PPh₄][Et₄N]₂[S₂MoS₂CuS₂MoS₂]  of the hetero metal sulfido core of the orange protein (ORP) of the sulfate reducing organism, Desulfovibrio gigas :

Structure of native Orange Protein from Desulfovibriogigas

Structural mimicry : Structure of the synthesized  model of Orange Protein

Halogen adduct

                     

 Methanol adduct                                             Ethanol adduct                                                                                             

DMF adduct

DMSO adduct of β-substituted Calix[4] pyrrole

A typical widely used tubewell contaminated with arsenic (Shuklaganj, Kanpur) displaying unhygienic surroundings with waterlogged,

Microorganisms have been implicated in the release of arsenic into drinking water involving bio-electrochemical reactions. Iron reducer has been shown to release captive arsenic from insoluble ferric oxyhydroxide– arsenic oxide adduct. Sulphate reducing bacteria (SRB) and Enterobacteriaceae may play a similar role by releasing hydrogen sulphide. The case of arsenic mobilization in water may be complex and varied. Arsenic contamination in Kanpur, northern India, 1000 km upstream of the Gangetic delta, added a new dimension to understanding the cause of its release in water. We propose that passive arsenic carried by the Ganges in the soil for centuries may be activated by unhygienic use of tubewells during the past three decades. We modelled the soil redox-chemistry prevalent under such conditions. We show that SRB grow in the vicinity of tubewells due to the availability of abundant food as fatty acids and sulphate as electron acceptors from soaps and detergents to release arsenic. In the absence of soap, Enterobacteriaceae play the same role. We also show that 26 commonly used soaps and detergents in India contain alarmingly high concentration of soluble arsenic, contaminating surface water.

Environment: Global warming and erratic rain fall: Besides  green house effect  the second cause is absorption of visible light  by  black carbon (BC) accumulated in aerosol in the atmosphere. Degradation of BC is not easy as these contains very stable carbon nano tube. Deposition of CNT on cobweb narrating the ready dispersion of CNTs in the environment from burning  fossil fuel  including burning of candle, oil lamp or even incense stick.

Metal d-orbital of Fe(III) porphyrinogen

Metal d-orbital of Co(II) porphyrin : left is penta coordinated and right is hexa coordinated